THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

PRESENTED BY

PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID

.0 C, GOODY
DICTIONARY

OF

GEOLOGY AND MINERALOGY

COMPRISING SUCH TERMS IN

NATUEAL HISTOEY

AS ARE CONNECTED WITH

THE STUDY OF GEOLOGY

WILLIAM HUMBLE, M.D., F.G.S.

THIRD EDITION, REVISED

XjOlSTDOlST
CHARLES GRIFFIN AND COMPANY

10, STATIONERS' HALL COURT

r ./I

PKEFACE.

Iisr submitting tlie following pages to public approbation, or public censure,
I avail myself of the accustomed privilege to offer a few prefatory obser-
vations ; explanatory, on the one hand, of the motives which led to their
preparation ; and deprecatory, on the other, of severity of criticism.

The labours of the lexicographer greatly differ from those of authors
generally. Dr. Johnson has observed, " every other author may aspire to
praise ; the lexicographer can only hope to escape reproach, and even this
negative recompenee has been yet granted to very few. It is the fate of
those, who toil at the lower employments of life, to be rather driven by
the fear of evil, than attracted by the prospect of good ; to be exposed to
censure, without hope of praise; to be disgraced by miscarriage, or
punished for neglect, where success would have been without applause, and
diligence without reward. Among these unhappy mortals is the writer of
dictionaries ; whom mankind have considered, not as the pupil, but the
slave of science, the pioneer of literature, doomed only to remove rubbish
and clear obstructions from the paths through which learning and genius
press forward to conquest and glory, without bestowing a smile on the
humble drudge that facilitates their escape."

When I commenced collecting materials for the present work, I was
induced to undertake the labour from a conviction that something of the
kind was greatly needed. At entering on the study of geology, scarcely
had I read through a single page, ere I found my difficulties much en-
hanced by the non-existence of a dictionary, containing such technological
terms as are peculiar to this branch of science, and, for a time, I was fre-
quently obliged to pass over words, without any distinct comprehension of
their force or application. Assuredly, some writers on geology have
appended a glossary to their productions ; but, I need scarcely say, these
are, for the most part, necessarily meagre and ineffectual. The very
necessity, also, for their insertion, I may, perhaps, claim as one of the
strongest arguments in justification of my present attempt.

It can hardly, however, be adduced as a charge of inattention to the
wants of the student, against the writers on geology, that no dictionary

IV.

relating to its nomenclature has already appeared. Geology may still be
regarded as in its infancy ; it is, as it were, almost a creation of the pre-
sent century ; it may, not inaptly, be termed a new science ; for, although
Pythagoras, and Aristotle, and Strabo, were, to a certain extent, geologists;
although Ovid puts into the mouth of the Samian philosopher—

"Vidi factas ex aequore terras:
Et procul a pelago conchae jaeuere marinse ;
Et vetus inventa est in raontibus anchora summis;
Quodque fuit campus, vallem decursus aquarura
F«cit ; et eluvie mons est deduetus in aequor:
Eque paludosa siccis humus aret arenis;
Quaeque sitira tulerant, stagnata paludibis hument.'*

although, from time to time, theories of the earth have been published,
and hypotheses the most crude, and fanciful, and illusory have been pro-
pounded ; although men have been found so blind as to argue in favour of
a plastic force ; although, almost even in our own days, Vulcanist would
have submerged Keptunist in his own aqueous deposits, and Neptunist
would have torrefied Yulcanist in the igneous causes which he advocated ;
although, for upwards of two thousand years, geology may be said to have
had its students and its advocates ; yet, till within the last half century, it
has never deserved the name of a science. Mixed up and confounded with
cosmogony, it continued in a state of flux and reflux, at one time making
advances, at another retrograding, till Hutton, in 1795, declared that
"geology was in no ways concerned with questions as to the origin of
things." ISTor was it till, throwing aside all preconceived notions, geolo-
gists determined to found, and gradually advance, step by step, their
theories on sound induction, that geology, in the magnitude and sublimity
of the objects of which it treats, second only to astronomy, assumed its
proper position in the order of scientific pursuits.

"With the great increase of knowledge in geology, there necessarily
sprang up a new nomenclature, and although this particular branch of
technological lexicography may, and does, admit of much modification, it
appears to me that it has at this time become sufficiently established to
warrant, and call for, the issuing of a dictionary of geological terms.

Nomenclature being in itself an important part of science, I trust I may
be excused for offering in this place a few observations on the subject. It
is perhaps a very natural weakness that men should desire to distinguish
things by names of their own appointing ; but, inasmuch as a redundancy

V.

of names is prejudicial to the interests of science ; perplexing, and often
disgusting, to the student ; and, in fact, raises an unnecessary obstruction
in the path of knowledge; it becomes a subject of grave consideration
whether the imposition of a new name, in lieu of one already become con-
ventional, though that which has become conventional may, probably, not
be the best or most appropriate that could have been chosen, be not a
hazardous and injudicious course. It has been remarked by one of the
most scientific men and greatest philosophers of the present day, Sir John
Herschel, " it appears doubtful, whether it is desirable, for the essential
purposes of science, that extreme refinement in systematic nomenclature
should be insisted on. In all subjects where comprehensive heads of
classification do not prominently offer themselves, all nomenclature must be
a balance of difficulties, and a good, short, unmeaning name, which has once
obtained a footing in usage, is preferable almost to any other."

These remarks are the more readily offered, in consequence of a fear,
which I trust is groundless, arising out of, and caused by, the occasional
observations of some of our most able geologists. Thus, I find one author
objecting to the term tertiary, as applied to the supra-cretaceous deposits,
stating it to be exceedingly objectionable: I turn over the pages of another
great luminary, and I find that "the name of tertiary has been given with
much propriety; that the name of super-cretaceous is peculiarly inappro-
priate, and that if a new name were necessary, post-cretaceous should have
been chosen." Every neophyte in geology now knows that the tertiary
deposits have been divided into eocene, miocene, and pliocene, the last being
subdivided into older and newer pliocene : this also is objected to, and it is
said, " if it be considered convenient to divide the supra-cretaceous rocks
of Europe into three or more sub-groups, names which imply their actual
geological position in the series, such as ' superior/ ' medial,' and ' infe-
rior,' 'upper,' 'medial,' and 'lower,' or others of the like kind, would
seem preferable to those derived only from a per-centage of certain organic
contents." To multiply instances of this kind, would, however, be useless,
and the sole motive for adducing the above, springs from a desire of
restraining, as far as may be, a too natural fondness for innovating on
established nomenclature.

It is most desirable that geologists should endeavour to avoid a very
great evil which has gradually obtained in, and now sadly clogs, the pur-
suit of mineralogy. The redundancy of terms there introduced is most
painfully bewildering, as the following instance will illustrate : — " The
nomemclature of most minerals is at present so encumbered with synonyma,

VI.

that it has become exceedingly perplexing to the student. The mineral
which is called epidote by Haiiy, is named pristazit by Werner, thallite by
Lemetherie, akanticone by Dandrada, AelpUniie by Saussure, glassy actinolite
by Kirwan, arendalit by Karsten, glamger strahlstein by Emmerling ; la
rayonnante vitreuse by Brochant, prismatoidischer augit-spath by Mohs,
&c., &c."*

To enter, here, on any defence of geology, against the groundless objec-
tions of weak, but amiable opponents, would be to travel out of the record.
Happily, the mists of delusions, and the prejudices consequent on long-
cherished and preconceived notions, are rapidly clearing away before the
lucid and delightful, and unanswerable statements and views of the galaxy
of learned, and scientific, and pious geologists of the present day. I trust
I may be permitted to quote from one of these a most happily conceived
and beautifully expressed passage: — "How then can they, by whom the
magnificent truths of elapsed time and successive generations have been
put in clear and strong evidence — how can they be expected to yield to
false notions of philosophy, and narrow views of religion, the secure
conviction that, in the formation of the crust of the earth, Almighty
wisdom was glorified, the permitted laws of nature were in beneficent
operation, and thousands of beautiful and active things enjoyed their
appointed life, long before man was formed of the dust of the ancient
earth, and endowed with a divine power of comprehending the wonders of
its construction ? It is something worse than philosophical prejudice, to
close the eyes of reason on the evidence which the earth offers to the eyes
of sense ; it is a dangerous theological error, to put in unequal conflict a
few ill- understood words of the Pentateuch, and the thousands of facts
which the finger of God has plainly written on the book of nature; folly,
past all excuse, to suppose that the moral evidence of an eternity of the
future should be weakened by admitting the physical evidence for an
immensity of the past."f

It remains for me to add a few words only, as deprecatory of severe
criticism. No one can be more aware than myself of the numerous errors
and deficiencies everywhere pervading this small volume : for these I urge
nothing, even in extenuation. For myself, it is sufiicient that I have
derived from its preparation much information, great gratification. I
entertain no morbid sensitiveness respecting the fate that awaits it. "With

Professor Cleavel*nd. f Professor Phillips.

Vll.

our prince of lexicographers I may say, " I dismiss it with frigid tranquil-
lity, having little to fear or hope from censure or from praise."

The necessity created, by preparing such a book for the press, for care-
fully looking into and examining the opinions of various authors on the
same subject, has made me acquainted with many works which, otherwise,
I never might have perused ; and I have, from this circumstance alone,
reaped a rich reward of the purest pleasure ; and, though critics may in
unmeasured terms condemn, it is more than probable that

" Seu ine tranquilla senectus
Exspectat, seu mors atris circumvolat alls;
Dives, inops, Romae, seu fors ita, jusserit, exsul;
Quisquis erit vitae, scribara, color."

PEEFACE TO THE THIED EDITION.

A PEW years since, I was informed by my publisher that every copy of
the two editions of my Dictionary had been disposed of, that the work was
in demand, and urging me to prepare a third edition. Although I had by
me a large mass of additional matter, I was, at that time, so unceasingly
occupied with professional duties, that I had not leisure even to arrange
the collected materials. Subsequently, from an affection of the eyes, I
abandoned all idea of again taking up my pen as an author. A desire to
aid in promoting the spiritual welfare of my fellow creatures, in the
erection of a new church, has now induced me to offer a third edition ;
an edition by no means such as I could have wished, inasmuch as I have
been compelled to abbreviate many portions, and to omit others, lest I
should swell the volume to a magnitude beyond the reach of purchasers
generally.

"With these few prefatory observations I close my lexicographical
labours ; not from disinclination, but from increasing inability consequent
on impaired vision.

Stonelands, February 16th, 1860.

A DICTIONARY

ABU

A. In words of Greek derivation, A
is used privatively, or in a negative
sense ; — as acephalous, without a
head ; acaulous, having no stem ;
apetalous, having no petals; aco-
tyledonous, having no cotyledons,
&c. «

ABARTICTJLA'TION. (from db and arti-
culatio, Lat.) That kind of articu-
lation which admits of manifest
motion ; it is also called diarthro-
sis, from the Greek word SidpOpwai s,
and dearticulation.

ABBREVIATED, (abbreviatus, Lat.)

1 . In botany, an epithet for the
perianth. An abbreviated perianth
is shorter than the tube of the
corolla, as in Pulmonaria maritima.

2. Shorter than a correspondent
part.

ABDO'MEN. (abdomen, Lat. abdomen,
Fr. dbdomine, It.) The large cavity
commonly known as the belly,
containing the organs more imme-
diately concerned in the process of
digestion, as the stomach, liver,
spleen, pancreas, bowels, &c.

ABDO'MINAL. (from abdomen.)

1 . Pertaining to the abdomen or

belly.

2 Fishes belonging to the order

abdominales, or the fourth order of

Linnaeus.

ABDOMINA'LES. The fourth order of
fishes in the arrangement of Lin-
naeus; they have ventral fins be-
hind the thoracic, or fins placed on
the belly, and the branchia ossicu-

lated; they chiefly inhabit fresh
water. The salmon, trout, smelt,
&c., are examples.

ABDU'CENT. (from alduco, Lat.) The
name given to those muscles which
serve to open or draw back parts
of the body; their opposites, or
antagonists, are called adducent.

ABDTTC'TOR. (abducteur, Fr. alduttore,
It.) The same as abducent.

ABERRA'TIOIT. (abberatio, Lat.)

1. A certain deviation in the rays
of light, from the true or geometri-
cal focus of reflection or refraction,
in curved specula or lenses.

2. A deviation from the ordinary
course of nature.

ABNO'RMAL. | abnormis, Lat.) Ir-

ABNO'RHOTJS. j regular; unwonted;
unnatural.

ARNO'RMITY. Departure from natural
formation ; irregularity.

ABRA'NCHIA. (from a, priv. and
(3pd^Wa, Grr.) Animals destitute
of gills, and having no apparent
external organs of respiration.

ABRANCHIA'TA. The third order of
articulata, having no apparent ex-
ternal organs of respiration, but
seeming to respire, some, by the
entire surface of the skin, others,
by internal cavities. The abran-
chiata are divided into two families ;
the - first, Abranchiata setigera,
comprising the Lumbrici and Nai-
des of Linnaeus; the second, Abran-
chiata asetigera, comprising the
Hirudo and Gordius of Linnaeus.

ABE

I 2]

A 0 A

ABRTJ'PT. (abruptus, Lai) Broken ;
craggy; steep; precipitous. In
botany, applied to leaves, when the
extremity of the leaf is, as it were,
cut off by a transverse line.

ABBTJ'PTLY PIN'NATE. Applied to
pinnate leaves, terminated neither
with a leaflet nor a tendril.

ABSO'BBENT. (from absorleo, Lat.)

1. Any substance possessing the
property of absorbing, or sucking
up, fluids, or neutralizing acids;
as the earths, alumina, magnesia,
&c.

2. In anatomy, the absorbents are
small pellucid tubes, which have
been discovered in most parts ef
the body, and are supposed to exist
in all. The absorbents begin by
numberless open mouths, too mi-
nute to be visible to the naked eye;
by the assistance, however, of
glasses, the orifices of the lacteals
have been seen in the human body,
and those of the lymphatics in
certain fishes.

ABSO'BBENT SYSTEM. This consists of
the absorbent vessels and conglo-
bate glands; the former are divided
into lymphatics and lacteals, and
the thoracic duct, or common
trunk, in which they terminate.

ACA'LEPHA. (a/ca\^0iy, a nettle, Gr.)
A class of zoophytes found swim-
ing in the waters of the ocean.
The acalephse are divided in to orders,
namely, the A. simplicia, and A.
hydrostatica. The latter, or hy-
drostatica, are recognized by one
or more bladders commonly filled
with air, by the aid of which they
suspend themselves in their watery
element. "In all parts of the
ocean," says Professor Grant, " are
numerous gelatinous animals, for
the most part of a simple and
transparent texture, such as the
Hedusa and Portuguese man-of-
war, and numerous other genera.
For the most part, those soft gela-
tinous animals (which are entirely
aquatic, and all of them marine)
possess a property by which they

excite inflammation, when they
touch the surface of the skin, like
nettles. The Acalephae scarcely
possess a trace of a nervous system,
and are all aquatic. They float,
for the most part, by the action of
their own muscular power, or by
air-sacs, or by cilia. They feed
upon animals of extreme minute-
ness— for the most part, on the
microscopic crustaceous animals,
which abound in the ocean as in
other waters." Cuvier places the
Acalephse in the third class of the
fourth great division of the animal
kingdom, or Radiata. Linnaeus
placed them in the class Zoophyta,
order Gelatinous zoophytes. See
Malactinia.

ACAI/T'CTNOTJS. A term applied to
plants which want a calyx.

ACA'MAS, A genus of fossil multilo-
cular, straight and conical shells ;
mouth round and horizontal; si-
phuncle central; summit pierced
by eight small tuberculated aper-
tures, disposed round a stelliform
figure ; the septa conical, plaited at
the bottom, and plain at the edge.
The substance spathose, similar to
that of belemnites. Parkinson.

ACANA'CEOTJS. (from a/cai/o?, Gr.)
Armed with spines or prickles.

ACA'NTH. The acanths constitute a
family of ichthyolites, of the Old
Bed Sandstone, rich in genera and
species, forming an intermediate
link between the placoids and the
ganoids.

ACA'NTHA. (axavOa, Gr.)

1 . In botany, the spine or prickle
of a plant.

2. In zoology, a term for the
prickly fins of fishes.

3. In anatomy, the spinous pro-
cess of a vertebra.

ACANTHA'CEOITS. (acanthace, !Fr.)
Possessing spines or prickles.

ACAN'THODES. The name assigned
to a genus of ichthyolites of the
old red sandstone, characterised
by having a spine or thorn on
each fin.

A C A

[3]

A C IT

ACANTHOPTER'YGII. (from uicavda, a
thorn, and irrcpvg, a wing, Gr.)
Thorny-finned fish. Cuvier divi-
ded all recent bony fishes into two
great orders, the Malacopterygii,
and the Acanthopterygii. In the
acanthopterygii the rays are stiff
continuous spikes of bone, each
standing detached as a spear, with-
out joint or branch. The perch
will serve as a familiar illustration
of this order.

ACANTHOPTERY'GIOTJS. (from aicavOa
and Trrcpvg, Gr.) A term applied
to those fish whose back fins are
osseous and prickly. The acan-
thopterygii are the first, and by far
the most numerous division of or-
dinary fishes.

AcANTHoeE'pHALA. (from uKCLvQa and
/ce0aX9J, Gr,) An intestinal worm
belonging to the order Parenchy-
mata, class Entozoa.

ACAN'TICONE. A sub-species of pris-
matoidal augite, occurring princi-
pally in primitive rocks, such as
mica-slate, gneiss, &c. Known
also as pistacite and epidote.

A'CARUS. (uKapi, Gr. animal minu-
tissimum.) The tick or mite. A
genus of insects belonging to the
order Aptera. The Acarus has
eight legs, two eyes, and two
jointed tentacula. The female is
oviparous, and excessively prolific.
Authors estimate tlie number of
species variously; Linnseus enu-
merates 35, and Gmelin 82 species.
Most of these are very small and
almost microscopical. Some are
parasitical, living in the skin of
animals : some of the coleoptera
are found covered with them.

ACATJ'LOTTS. (from a, priv, and KavXbs,
Gr.) A term applied to plants,
the flowers of which have no
pedicle or stalk.

ACCI'PITRES. (Lat. from accipiendo.}
Rapacious birds ; the first order of
birds in the Linnsean system of
ornithology. The Accipitres are
known by their hooked beak and
talons j they feed upon other birds,

as well as upon the weaker quad-
rupeds, and reptiles. They have
been divided into two families, the
diurnal and the nocturnal.

ACCI'PITRINE. Belonging to the order
Accipitres ; rapacious.

ACCLI'MATED. (acclimate), Fr.) Ac-
customed to a climate not natural
to it.

ACCLIMA'TION. Neutralization to for-
eign climate.

ACCLI'MATIZE. (acclimater, Fr.) To
accustom to foreign climate ; to
accustom to the temperature of a
new climate. A term applied both
to persons and things ; to animals
and plants.

ACCRE'TIOST. (accretio, Lat.) Increase,
or growth, by the accession of new
parts. Bacon says, plants do nour-
ish ; inanimate bodies do not ; they
have an accretion, but no alimenta-
tion.

ACCRE'TIVE. Increasing, or growing,
by the accession of new parts.

ACE'PHALA. (a, priv. and Ke0aXi}, the
head, Gr.)

1. A class of animals not having
any head, but merely a mouth,
concealed between, the folds of their
mantle ; the mouth is always eden-
tated : the oyster furnishes an ex-
ample. All the acephalae are aqua-
tic.

2. In entomology, an order of in-
sects.

ACE'PHALOUS. (acephale. Fr. a/ce0aXo9,
Gr.) Headless ; this term was given
by Cuvier to animals not having
any head.

ACE'RB. (acerlus,^ Lat. acerle, Fr.
acerlo, It.) Acid with an addition
of roughness : the taste of an unripe
sloe is a familiar and good illustra-
tion.

ACERBITY, (acerlitas, Lat. acer-
bite, Fr.) Sourness combined with
roughness of taste.

ACERO'SE. V (acerosus, Lat.)

A'cERoirs. j 1. Chaffy, branny.
2. In botany, leaves linear, needle-
shaped, everywhere of an equal
breadth, mostly acute, and rigid.

ACE

A C I

ACEROTHE'EIUM. An extinct genus
of animals, constituting a link con-
necting Palceotherium with Rhino-
ceros.

ACE'SCENT. (adcescens, Lat. acescent,
Fr.) That has a tendency to be-
come sour spontaneously, or by
spontaneous decomposition.

ACETA'BULUM. (Lat.)

1. A cavity in a bone formed for
receiving the head of another bone,
and thus named from its cup-like
shape ; it is more particularly used
for expressing the cavity in the os
innomination, which receives the
head of the femur, or thigh-bone.

2. In botany it is used for the
cotyledon.

ACE'TAET. (from acetum, Lat.) An
acid pulpy substance found in some
fruits, especially the pear, sur-
rounding the core ; it is enclosed
in a congeries of small calculous
bodies towards the base of the fruit.

A'CETATE. Any salt formed by the
union of acetic acid with a salifi-
able base, as acetate of iron, acetate
of potash, &c. The acetates are all
soluble in water; many of them
are deliquescent, and crystallizable
with difficulty ; they are decom-
posed by the sulphuric acid.

ACHA'TES. («xa™/9, Gr.) The agate.

ACEOUS. Terminations in aceous and
icius, express a resemblance to a
material; those in eous indicate
the material itself ; as membrana-
ceous, resembling membrane ; tufa-
ceous, resembling tufa ; membrane-
ous, skin itself.

ACHA'NIA. (from «xo^§, Gr. ab a,
priv. et xa/j/w.) In botany, plants
whose corolla does not open. Order
Polyandria, class Monodelphia ;
natural order Columnifera3.

ACHELOIS. A genus of fossil shells,
described by De Montfort as being
of. a conical form, with conical
septa, but Parkinson considers its
characters not sufficiently ascer-
tained at present to warrant its
being considered a distinct genus.

A'CHTEITE. Emerald malachite.

ACI'CULA. (Lat.) A prickle or fine
spine.

ACI'CTJLAE. In the shape of a needle :
rocks of granite, having sharp,
needle-like summits, are thus
named.

ACI'CTJLAELY. Needle -like.

ACID, (acidum, Lat. acide, Fr.) The
word acid, originally synonymous
with sour, and applied only to bodies
distinguished by that taste, has been
gradually extended in its significa-
tion, and now comprehends all sub-
stances possessed of the following
properties : —

1. When applied to the tongue,
they excite that sensation which is
called sourness.

2. They change the blue colours of
vegetables to a red.

3. They unite with water in almost
any proportion, with a condensa-
tion of volume, and evolution of
heat.

4. They combine with all the alka-
lies, producing effervescence during
the combination, and with most of
the metallic oxides and earths, and
form, with them those compounds
which are called salts.

The acids terminating in ous pro-
duce compounds to which the termi-
nation ite is given, as, e. g. the
combination of sulphurous acid and
potassa is a sulphite of potassa ; the
acids ending in ie form compounds
to which the termination ate is
applied ; the combination of sul-
phuric acid and potassa is a sulphate
of potassa.

ACIDASPIS. (a/«s, cuspis, and ao-?™?, cly-
peus vel scutum, Gr.) The name as-
signed by Sir E. Murchison to a genus
of trilobites, the generic characters
of which he thus describes ; ' ' capitis
scutum marginatum, antice sub-
truncatum, trituberculatum : tuber-
culo media postice in mucronem
desinente." Although, says the
talented author of the Silurian
system, most unwilling to multiply

A C I [

names, the rery remarkable form
of the head or shield of this trilo-
bite, the posterior end of its central
lobe projecting over the body in
the form of a stomacher, and render-
ing it totally distinct from any pub-
lished figure, induces me to propose
it as a new genus." Two species
have been described, namely A.cidas-
pis Brightii and Abispinosus. They
occur in the Wenlock limestone of
the Malvern Hills.

ACI'DIFIABLE. Any substance capable
of being converted into an acid, by
the union of an acidifying princi-
ple without decomposition.

ACL'DULOUS. (acidulus, Lat.) Slightly
acid ; sub-acid ; sourish.

ACINA'CIFORM. (from acinaces and
forma, Lat.) Cimiter shaped; a
term applied to leaves, one edge of
which is straight and thick, the
other curved and thin.

A'CINOSE. Iron ore. A variety of
iron ore found in masses, and com-
monly lenticular. Colour, gene-
ralljT, brownish red : lustre metallic :
texture granular : hardness 5 to 9 :
brittle.

A'CINTJS. (Lat.) Acini PL Each
separate part of a compound berry
containing a seed : compound ber-
ries consist of many simple acini
united together, as the raspberry,
blackberry, &e.

ACOTYLE'DON. (from a, priv. and KOT-
v\^wvf Gr.) A plant whose seeds
have no cotyledon, or side-lobes.

ACOTYLE'DONOTIS. Plants, whose em-
bryos have no lobes, or seminal
leaves ; not having cotyledons, or
seed lobes.

ACROCERAU'NIAN. (from axpo* and
Kepawos, Gr.) A term given to
some mountains, supposed to be
especially subject to the effects of
lightning.

A'CROGEN. (from dV/>o<? and ^ewdw,
Gr.) An acrogen is a cylindrical
plant growing at its point only,
and never augmenting in thickness
after once formed.

]

ACT

ACRO'MIOX. (from anpoa and

Gr.) The humeral extremity of
the spinous process of the scapula ;
situated over the upper end of the
humerus, and contributing to the
protection of the shoulder joint.

A'CROSPIEE. (from a/c/aos and GTrelpa

Gr.) The shoot or sprout of a
seed, also called the plume or
plumule.

ACTEONELLE. A genus of cylindrical
smooth univalves, with elevated
spire, aperture entire, lengthened,
moderately wide anteriorly, narrow
posteriorly ; columella smooth,
rounded ; lip thin. It occurs fossil
in the oolite.

ACTI'NIA. The sea-anemony, a genus
of the order Vermes mollusca. The
fleshy body of the actinia is fre-
quently ornamented with bright
colours, and exhibits numerous ten-
tacula placed round the mouth in
several ranges, like the petals of a
double flower, from which it has
obtained its name of sea-anemony.

ACTINO'CERAS. A genus of chambered
fossil shells belonging to the family
of the Orthocerata, and established
by Brenn ; it is a straight conical
camerated shell with septa, as in
Orthoceras, the siphuncle is external
but divided into chambers, and
within it is a continuous tube which
appears to have been capable of
contraction and expansion, and is
furnished with verticillate radii
which connect the tube with the
walls of the syphon. Lycett.

ACTING COMAX. A genus of fossil
shells, having the form of belem-
nites.

ACTINOLEPIS. An ichthyolite of the
old Red Sandstone.

ACTINOCRINITES. (from 0/CT/J/OJT09,

radiated, and Kplvov, a lily Gr.)
Radiated, lily-shaped animals. A
genus of fossil encrinites established
by Miller. There are many species,
some of which are found in the
Silurian rocks and in the carboni-
ferous limestone. Mr. Phillips says

ACT

ADA

that Mr. Miller himself is in error
when he speaks of the species A.
Moniliformis as belonging to the
Mountain Limestone. The generic
characters of the genus are thus
described by Mr. Miller. A crinoidal
animal, with a round column com-
posed of numerous joints, perforated
by a round alimentary canal. At
the summit of the column is placed
an operculum formed of three plates
on which five first costals and one
irregular costal adhere ; which are
succeeded by the second costals and
intercostals and the scapula, from
whence five arms proceed, forming
two hands, with several tentacu-
lated fingers. Round side arms
proceed at irregular distances from
the column which terminates at the
base in a fascicular bundle or root
of fibres.

ACTI'NOLITE. (from aic-rlv and \lOo$,
Gr.) A variety of hornblende. Its
constituent parts are silica 46 '26,
magnesia 19'03, liine 13'96, alu-
mina 14-48, protoxide of iron 3.43,
protoxide of manganese 0' 36, fluoric
acid 1-60, water, &c. 1'04. This
variety of hornblende rarely occurs
in the secondary rocks, being princi-
pally confined to those of the pri-
mary class. It is of a green colour.
Cleaveland says " this mineral pos-
sesses all the essential characters of
hornblende. In fact common horn-
blende and actynolite insensibly
pass into each other. The actynolite
has usually a greater translucency,
a more lively green colour, arising
from the chrome which it contains,
and differs in the result of fusion
by the blowpipe. Jameson places
actynolite in the hornblende family
but, as a distinct species, divided it
into four subspecies, 1. asbestous
actynolite, 2. common actynolite,
3. glassy actynolite, and 4. granu-
lar actynolite. He remarks "Haiiy
is of opinion that actynolite and
hornblende belong to the same
species, because his observations

ACTJ'LEATE
ED*

shew an identity in their primitive-
forms. Count de Bournon, on the
contrary, proves that their primitive
forms are not the same ; hence he
infers that they are distinct species.
These two minerals are further dis-
tinguished by their colour, fracture,
and crystallizations ; those of acty-
nolite being few in number and
simple ; whereas those of horn-
blende are more numerous and com-
plex; and lastly, they differ re-
markably in geognostic situation."
Phillips places actynolite amongst
the varieties of hornblende, and
divides it into crystallized asbesti-
form, and glassy actynolite.

ACTI'NOLITE-SCHIST. A metamorphic
rock, consisting principally of acti-
nolite, with an admixture of mica,
quartz, or felspar; its texture is
slaty and foliated.

ACTINOLI'TIC. Containing actinolite;
of the nature of actinolite.

(*ad**tw> Lat-)
Prickly; having
spines or prickles.
Applied to leaves armed with
prickles. Used to denote prickles,
fixed in the bark, in distinction
from thorns which grow from the
wood.

ACTJ'LETJS. A prickle or spine, arising
from the bark only,andnot growing
from the wood.

ACTJ'MINATED. (acuminatus, Lat.)
Ending in a point ; sharp-pointed,
the decrease being very gradual.

A'DAMANT. (a&fytas, Gr.) A name
given to different stones of exces-
sive hardness, as to the diamond.

ADAMA'NTINE SPAE. Imperfect corun-
dum; a variety of rhombohedral
corundum, nearly analogous to per-
fect corundum, containing from 3
to 5 per cent, of silica, and 1 to 2
of oxide of iron. 1 1 occurs massive
and in crystals. The crystals brought-
from India are the most pure.

ADA'MIC EARTH. A name given to
red clay.

ADA

D E

A'DAPIS. One of the extinct pachyder-
mata, found in the gypsum quarries
of Montmartre. The form of this
creature most nearly resembled that
of a hedge-hog, but it was three
times the size of that animal : it
seems to have formed a link con-
necting the pachydermata with the
insectivorous carnivora. — Buck-
land.

ADDU'CENT. (from adduco, Lat.) A
name given to those muscles which
bring forward, close, or draw to-
gether, the parts of the body to
which they are attached ; their
antagonists are termed abducent.

ADE'NOID. (from a£i)i>, a gland, and
eidos, form, Gr.) Glandiform ;
having the shape of a kernel, al-
mond, or gland ; glandulous.

ADIPOCERA TION. The process of being
converted into adipocire.

A'DIPOCERE. | (adeps, fat, and cera,

A'DIPOCTBE. j wax, Lat.) A sub-
stance resembling spermaceti, pro-
duced by the conversion of animal
matter exposed to running water ;
in this way animal matter may be
converted into a soft, unctuous, or
waxy substance in the space of a
little more than a month ; but
adipocire has also been produced,
though not so rapidly, by the heap-
ing together large masses of putre-
fying animal matter, as was dis-
covered on the removal of a very
great number of bodies from the
burial ground of the Church des
Innocens at Paris, 1787. Adipocire
possesses many of the properties of
fat combined with a portion of am-
monia. It was first discovered by
Fourcroy.

ADIPOCE'RE MINERAL. A fatty matter
found in the argillaceous iron ore
of Merthyr : it is fusible at about
60°, and is inodorous when cold, but
when heated it emits a slightly
bituminous odour.

A'DIT. (aditus, Lat.) The shaft or
entrance into a mine, usually made
in the side of a hill, for the convey-

ance of ore, and the carrying off of
the water. It is the first object of a
miner, in the working of a mine,
to drive a passage or adit from the
nearest low ground or valley to
meet the shaft, for the purpose of
conveying off the water, which is
raised to the adit level by the
means of the steam engine. It will
therefore be obvious that the depth
of the adit from the surface of the
mine, must depend on the height
of the ground in which the mine
is, and the depth of the neighbour-
ing valley. The depths of different
parts of mines are usually dated
from the adit level.

ADMI'XTION. (admisceo, Lat.) The
union of various bodies, or sub-
stances, by mingling them together.
In admixtion each body retains its
own character, and does not under-
go any chemical change, as in com-
position.

ADNA'TA. (adnatm, Lat.)

1. Those parts of animal, or vege-
table bodies which are natural, as
the nails, hair, &c.

2. Accidental parts, as fungi, misle-
toe, &c.

3. The external coat of the eye.
A'DISTATE. Growing to ; adhering. In

botany, it is used when a leaf ad-
heres to the branch or stem by the
surface or disk itself; applied to
stipules when they are fixed to the
petioles.

ADTJLA'RIA. (from adula, the summit
of a Swiss mountain.) Moonstone ;
a tran spar ent white- coloure d variety
of feldspar, with a silvery, or pearly
opalescence.

JE'DELiTE. A stone found in Sweden,
and thus named by Mr. Kirwan.
Its form is tuberose and knotty.
Texture striated ; sometimes resem-
bles quartz. Lustre from 0 to 1.
Specific gravity 2.515 after it had
absorbed water. Colour light grey.
Before the blow-pipe it intumesces,
and forms a frothy mass. Acids
convert into a jelly. A specimen,

A E L

JE R tr

analysed by Bergman, contained 69
silica, 8 lime, 20 alumina, 3 water.
— Thomson.

AE'LODON. A fossil saurian of the
oolite and lias.

A'ERATE. To combine with carbonic
acid.

A'EEATED. Combined with carbonic
acid, or fixed air.

A'E RATION. The combining with fixed
air, or carbonic acid ; the saturation
of a liquid with air.

AE'EIAL ACID. A name given by
Bergman to carbonic acid or fixed
air ; aerial acid is of greater specific
gravity than atmospheric air, and
extinguishes flame.

AE'ROLITE. (from afjp and X/0os, Gr.)
Called also meteorite. A name
given to meteoric stones, which,
occasionally, fall to the earth. No-
thing is positively known as to the
origin of aerolites : by some authors
they have been supposed to come
from the moon, being projected by
volcanic force beyond the sphere of
the moon's attraction ; by others
they have been thought to be
children of the air, created by the
union of simpler forms of matter.
They do not resemble any other
substance found on the earth, and
it has been indisputably proved that
they are not of terrestrial forma-
tion. The fall of these bodies has
been well ascertained, and has oc-
curred at different times, and in
various parts through many ages.
Some of these aerolites are im-
mensely large, from 300 Ibs. down-
wards. From an analysis of them,
they are found to agree in their
component parts. They are covered
with a thin crust of a deep black
colour, their exterior is roughened
with small projections, and they
are destitute of gloss. Internally
their texture is granulated, and of
a greyish colour. When carefully
examined, they appear to be com-
posed of a number of small spherical
bodies and metallic grains embedded

in a softer matter, composed, accord--
ing to the Hon. Mr. Howard, who
diligently and carefully studied
them, of silica, magnesia, iron, and
nickel. In addition to these sub-
stances, Yauquelin found chrome,
and Stromeyer discovered cobalt,
in aerolites : lime, alumine, and
manganese, have also been detected
in them. Meteoric iron has been
imitated by fusing iron with nickel.
"When it is considered how many
of these bodies have been seen, or
heard, to fall through the air, we
must conclude that they are very
numerous especially when we reflect
on the small proportion which must
be observed, and the small compar-
ative portion of the globe which is
inhabited, or habitable, by man.
The fall of meteoric stones, in the
opinion of some writers, is much
more frequent than is generally
supposed, hardly a year passing
without some instances occurring.

AERO'METER. (from a?}/> and /neTpov,
Gr. acrometre, Fr.) An instrument
for ascertaining the weight, or
density, of the atmosphere.

AERO'METET. (aerometrie, Fr.) The
science which treats of the proper-
ties of the air ; it comprehends not
only the doctrine of the air itself,
considered as a body, but also its
pressure, elasticity, rarefaction, and
condensation.

AERO'SCOPY. (from ar}p and aKOTrew,
Gr.) The observation of the air.

AEB.OSTATION, (from arjp, the air,
and larrffjii to weigh, Gr.) Primarily,
the science of weights suspended
in the air, but in the modern ac-
ceptation of the term, the art of
navigating in the air.

JEfiu'eiNous. (from (eruginosus, Lat.)
Partaking of the nature of the rust
of copper.

JERU'GO. Yerdigrease, or verdigris ;
rust of copper, formed by the com-
bination of an acid with copper.
Impure subacetate of copper. Yer-
digris is inodorous, and when first

A F F

[9]

A G A

applied to the tongue is nearly
insipid, though strongly styptic;
it leaves a metallic taste in the
mouth. It is poisonous ; sugar
acts as a specific against its poison-
ous effects.
.^EsxrvA'TioBr. (astivatio, Lat.)

1. The effect produced by summer
heat.

2. The mode in which the parts of
a flower, taken separately, are ar-
arranged in the bud.

JE'TITES. (aero?, Gr. aetite, Fr.)
Eagle-stone ; a variety of oxide of
iron mixed with clay. It is found
in masses, generally under, the form
of a rounded knob, something re-
sembling a kidney. It prevails in
the coal formations of England,
Wales, and Scotland, has a rough
surface, and is of a brown colour.
Specific gravity 4 to 7. Lustre of
the exterior metallic. It frequently
contains a sort of kernel, which
rattles on being shaken. It was
formerly in repute for several ex-
traordinary magical as well as
medical properties, such as prevent-
ing abortion, discovering thieves,
&c. It derives its name from a
a popular notion that it was found
in eagles' nests, where it was sup-
posed to prevent the eggs from
becoming rotten. See Nodular Iron
Ore.

AFFI'NITY. (affinis, Lat. affinite, Fr. af-
finitd, 1 1) The tendency which bodies,
dissimilar in their composition, have
to unite and form new compounds.
Different bodies are possessed of
different attractive powers, and if
several be brought together, those
which have the strongest mutual
affinities enter first into union.
Affinity, like sensible attraction,
varies with the mass and the dis-
tance of the attracting bodies. That
the course of affinity increases as
the distance diminishes, and the
contrary, is obvious ; for it becomes
insensible when the distance is
sensible, and exceeding great when

the distance is exceedingly dimin-
ished. Affinity agrees with sensible
attraction in every point which it
has been possible to determine.

AGALMA'TOLITE (from u^a\/ma and
\i'0os, Gr.) Figure-stone. A sub-
species of talc- mica, of different
colours, as white, red, brown, green,
and grey. It occurs massive. It
feels greasy, is translucent, and has
a conchoidal fracture. The finest
specimens are brought from China.
It does not contain any magnesia,
but in other respects it has the
character of talc.

A'GABIC. (agaricm, Lat.) The generic
name for the mushroom, a genus
of the order Fungi, class Crypto-
gamia. Gmelin enumerates nearly
400 species.

A'GARIC MINERAL. A variety of soft
carbonate of lime. It is found in
the clefts of rocks, or the bottom of
lakes, in pieces loosely cohering,
and it is so light as nearly to swim
upon water. It obtains its name
from its resemblance to a fungus in
colour and texture.

AGAR'ICIA. A genus of lamellated
stony polypifers, fixed with flat,
subfoliaceous expansions, the upper
surfaces only having stelliferous
grooves: the stars sessile, lamellous,
and in rows. This genus, which
much resembles Pavonia, differs in
having one surface only of its foli-
aceous expansions furnished with
stelliferous grooves.

A'GATE. (achates, Lat. a^ar^s, Gr.
agate, Fr. agata, It.) A siliceous,
semi-pellucid gem, of which there
are many varieties, not of great
value. Agates are principally com-
posed of quartz with various colour-
ing matters. Agates may be arti-
ficially coloured by immersion in
metallic solutions. Mr. Allan says
" Agate is an impure variety of
calcedony, of frequent occurrence in
the vesicular cavities of atnygdaloi-
dal rocks.- It presents the most
brilliant and the most varied colours,

A G G

i a

and, from its hardness and compact
structure, being capable of receiving
a high polish, occupies a distin-
guished position in most collec-
tions." Professor Jameson places
Agate amongst the members of the
Quartz family, constituting it a
distinct species. He says "it is
not, as some mineralogists main-
tain, a simple mineral, but is com-
posed of various species of the
quartz family, intimately joined
together. It is principally com-
posed of calcedony, with flint, horn-
stone, carnelian, jasper, cacholong,
amethyst, and quartz." Professor
Cleaveland says " the calcedony is,
however, the most common and
abundant ingredient, and may fre-
quently be considere'd the base of
the agate ; in fact, some agates are
composed entirely of calcedony dif-
ferently coloured." Werner divided
agates into Ribbon Agate ; Fortifi-
cation Agate; Breeciated Agate;
Moss Agate; Landscape Agate;
Tubular Agate ; and Jasper Agate.
As precious stones, agates are now
less esteemed than formerly: the
most valuable are the oriental.
When cut and polished, agates pre-
sent an appearance of waving lines,
sometimes accurately parallel, some-
times varying in breadth, and some-
times containing a resemblance to
vegetable forms, as mosses, ferns,
&c. Small agates are frequently
found in common gravel.

A'GATY. Of the nature of agate.

A'GGSEGATE. (aggregat, Fr.)

1. The complex, or collective re-
result of the conjunction, or acer-
vation, of many particulars: it
differs from a compound body, in-
asmuch as the union in the last is
more intimate than between the
parts of an aggregate.

2. In botany, a term used to ex-
press flowers composed of many
small florets, having a common
undivided receptacle; tho anthers
separate and distant, the florets

commonly standing on stalks, each
having a single or double partial
calyx. They are opposed to simple
flowers, and are usually divided
into seven kinds.

AGGREGATED. Collected ; accumu-
lated ; heaped together. A rock is
said to be aggregated when the
several parts of which it is com-
posed merely adhere and may be
separated from each other by me-
chanical means : thus in granite,
the several parts of which, quartz,
mica, and felspar, may be mechani-
cally separated, we have an instance
of an aggregated rock.

AGGBEGA'TIOW. (aggregation, Fr. ag-
gregazione, It.) The collection into
one mass of bodies having no natu-
ral connexion, but, by a species of
union, made to constitute one body.

AGSTO'STUS. (a^vica-ro^, Gr.) A fossil
genus of trilobites, established by
Brongniart, the Battus of Dalman.
Agnosti are found in the lower
Silurian rocks, especially in the
Llandeilo flags. In Norway, says
Sir E. Murchison, the Agnosti
occur in millions, but in our
rocks they are much less fre-
quent. Macleay does not consider
Agnostus to belong to the Trilo-
bita. The discovery of an entire one
in Bohemia, by Dr. Beyrich, proves
the agnostus to be a true trilobite.

AGNOTHE'RIUM. An extinct animal
of the miocene period, order Mam-
malia, allied to the dog, but of very
large size. One species only has
been found, at Epplesheim, in
Germany.

AIGUE MAHI'KE. A variety of topaz,
of a blueish or pale green colour.

AIGUI'LLES. (aiguilles, Fr.) The
needle-like points, or tops, of
granitic rocks.

AIGUI'LLB DE DKTT. A pyramidal
granitic mountain, according to
Bakewell, the most remarkable at
present known; the upper part,
or spire, rises above its base nearly
to a point, in one solid shaft, moro

ALA

[11]

ALB

than 4,000 feet; the summit being
11,000 feet above the level of the
sea.
A' LA. (ala, Lat.)

1. In botany, a term used for the
hollow, which either the leaf, or
the pedicle of the leaf, makes with
the stalk; the hollow turning, or
sinus, placed between the stalk or
branch of a plant and the leaf, and
whence a new offspring generally
rises. Sometimes it is used for
those parts of leaves otherwise called
lobes or wings. Those petals of
papilionaceous flowers placed be-
tween those other petals, distin-
guished as the vexillum and carina,
and which constitute the top and
bottom of the flower, are also called
alee.

2. In anatomy, the lobes of the
liver, the cartilages of the nostrils,
and the cartilaginous parts of the
ears, are called alse.

A'LABASTEK. (Alabaster, Lat. aXa-
pciffvpov, Gr.) Granular or massive
sulphate of lime. Alabaster is
found in this country accompanying
the salt deposits in Cheshire. It is
also most abundant at Montmartre,
in the neighbourhood of Paris. At
Hontaiont, in Italy, it is found in
blocks of such magnitude, that
statues of the size of life are occa-
sionally cut from them. Being
semi-transparent, it has sometimes
been employed for windows instead
of glass, and a church at Florence
is still illuminated by alabaster
windows. Instead of panes of glass,
there are slabs of alabaster 15 feet
high, each of which forms a single
window, through which the light
is conveyed. Alabaster may be
turned by the lathe, and is thus
formed into a great variety of orna-
mental articles.

ALAB'ASTBITES. (alalastrites, Lat.
a\af3a<npiTrj?f Gr.) Alabaster stone;
a kind of marble, whereof the
ancients made vessels for ointment ;
by Horace called onyx.

A'LALITE. Called also Diopside,
a variety of augite. It occurs
massive, disseminated, and crystal-
lized, with a vitreous external,
and pearly internal lustre ; it is
translucent, and either white or of
a pale green colour. It was named
by Bonvoison, from his finding a
variety of it near the village of
Ala, in Piedmont.

ALA'SMODOIT. A species of shells of
the genus Unio, having cardinal,
but no lateral teeth.

A'LATE. } (alatus, Lat.) "Winged.

ALA'TED. j In conchology, applied
to shells having an expanded lip,
or when any portion of them is
much expanded.

A'LBITE. Tetarto-prismatic felspar ;
soda felspar. A name given to
felspar, whose alkali is soda
instead of potash. Colour gene-
rally white, sometimes grey, green,
or red. Lustre upon faces of cleave-
age pearly, in other directions vitre-
ous. Albite forms a constituent
part of the greenstone rocks in the
neighbourhood of Edinburgh. It
is composed of silica, alumina, and
soda, with a trace of lime.

ALBI'TIC, Of the nature of albite ;
containing albite.

ALBUGI'NEA. [from dibits t Lai]

1. The fibrous membrane in the
eye, situate immediately under the
tunica conjunctiva.

2. One of the tunics of the testis.
ALBU'GINEOUS. ^albugineus, Lat.]

1 . The aqueous humour of the eye.

2. Resembling the white of an egg.
A'LBUM GB^'CTJM. The excrement of

dogs, wolves, hyenas, &c., feeding
or living on bones. It principally
consists of the earth of bones or
lime, in combination with phos-
phoric acid.

ALBTT'RNTJM. [alburnum, Lat.] Called
also sap-wood ; the interior white
bark of trees : it is this which
yearly becomes new wood ; the last
formed wood of the trunk of trees
and woody plants. It appears pro-

ALE

[12]

A L G

bable, that the new layers of albur-
num and liber, which are produced
each year on the outside of all
that preceded, are formed by the
descending fibres, or roots, of the
leaf-buds.

ALCYO'JSTIUM:. A genus of zoophytes,
the characters of which are, that
the animal grows in the form of a
plant ; the stem, or root, is fixed,
fleshy, gelatinous, spongy, or coria-
ceous, with a cellular epidermis,
penetrated with stellated pores, and
shooting out tentaculated oviparous
hydree. — Encyclop.

From the experiments of Hat-
chett, it appears that these animals
are composed principally of carbo-
nate of lime and a little gelatinous
matter. The alcyonium belongs to
the class Vermes, order Zoophyta.
Guvier places the alcyonium in
the order Coralliferi, class Polypi.
Much obscurity prevails in the
distribution even of the recent
species of the families of alcyonium
and spongia. Ellis makes their
distinction to consist in the presence
of polypi, as inhabitants of the
cells of alcyonia, and believes the
sponges to possess none of these
animalcules, but to be simply in-
vested with a living gelatinous
flesh. Lamark, however, supposes
the sponges to have polypi, like
the alcyonia, differing only in the
greater solidity of the fleshy parts
of the latter, which permit them
to be observed when removed from
the water; while those of the
former dry up instantly on being
taken out of their natural element.

ALCY'ONITE. Alcyonites are fossil
alcyonia, or zoophytes nearly allied
to sponges, the production or habi-
tation of polypi. — BaJzewell.

ALE'MBIC. (alamUc, Fr. lambicco, It.
alenibicum, Lat.) A vessel used in
the process of distillation, usually
made of glass or copper. Of alem-
bics there are two different forms,
the beaked and the blind, the former

having communication with the re-
ceiving vessel, the latter being
without such. The use of the
alembic has yielded to that of the
retort.

ALE'PIDOTE. (from «, priv. and XeTrJ?,
squama, a scale.) Any fish destitute
of scales, as the eel, cod-fish, &c.

A'LGA. (Lat.) Sea-weed.

A'LG^E. An order, or division, of the
Cryptogamas class of plants. It is
one of the seven families, or natural
tribes, into which Linna3us distri-
buted the vegetable kingdom. The
whole of the sea-weeds are compre-
hended under this division. The
plants belonging to this order are
described as having their leaf, stem,
and root all one. The depths at
which, according to Syell, some
of the alga3 live, is extremely
great, being no less than one thou-
sand feet ; " and although in such
situations there must reign dark-
ness more profound than night, at
least to our organs, many of these
vegetables are highly coloured." —
Principles of Geology.

M. Lainouroux states that the
groups of alga3, or marine plants,
affect particular temperatures or
zones of latitude, though some few
genera prevail throughout the
ocean. Some of the algse grow to
the enormous length of several
hundred feet, and are all highly
coloured, though many of them
must grow in the deep caverns of
the ocean, in total, or almost total,
darkness. From the observations
of Humboldt, who discovered green
plants growing in complete dark-
ness at the bottom of one of the
mines of Freyberg, it may be con-
cluded that light is not the only
principle on which the colour of
vegetables depends.

ALGALMA'TOLITE. Figure-stone. A
mineral, the finest varieties of
which we receive from China. A
sub-species of talc-mica. See Agal-
matolite.

ALL

[

A'LGOUS. (algosus, Lat.) Having the
nature, or characters, of sea- weed.

A'LKALI. (from the Arabic word kali,
with the usual prefix al ; the name
given by the Egyptians to the plant
called by us glasswort.) Any sub-
stance which, by uniting with an
acid, neutralizes or impairs its
activity, and forms a salt. Alkalies
possess the property of converting
vegetable blues to green, and yel-
lows to red. There are three kinds
of alkalies: 1. The vegetable alkali,
or potash ; 2. The mineral alkali,
or soda ; 3. The animal, or volatile
alkali.

ALKALI'NITY. The property of chang-
ing vegetable blues into green.

ALKALI'METEK. An instrument for
ascertaining the proportion of alkali
contained in any substance.

A'LKALOID. A body possessing some
of the properties of an alkali.

A'LKANET. The name of a plant the
root of which yields a fine red, and
is much used, by dyers.

A'LLAGITE. A mineral ; colour brown
or green ; massive; semi-opaque;
fracture conchoidal : it is a carbo-
silicate of manganese.

A'LLANITE. An orthitic melane-ore.
The cerium oxyde siliceux of Haiiy.
A mineral brought from Greenland,
and thus named after Mr. Thomas
Allan, of Edinburgh, who first dis-
tinguished it as a peculiar species.
According to the analysis of Dr.
Thomson, allanite was found to
contain silica 3 5 -4, oxide of cerium
33-9, oxide of iron 25-4, lime 9-2,
alumina 4*1, moisture 4.

It is of a black colour, inclining
to grey or brown. It is found
massive, or in acicular crystals.
External lustre imperfect, metallic;
internal, shining. Fracture con-
choidal. Opaque. Streak greenish
or brownish-grey. It is a siliceous
oxide of cerium.

ALLIACEOUS, (from allium, garlick,
Lat.) Resembling garlick ; a term
usually applied to substances which,

; ] ALL

on being heated, emit the odour of
garlick.

A'LLOCHROITE. A mineral variety of
the dodecahedral garnet. It is found
massive, of a green, brown, grey,
or yellowish colour ; lustre glim-
mering. It consists of silica, lime,
carbonate of lime, oxide of manga-
nese, oxide of iron, alumina, and
moisture. Before the blow-pipe it
melts into an opaque black enamel.
It was first discovered and described
by Dandrada, and hitherto it has
only been met with in an iron
mine, near Drammen, in Norway.
Sp. gravity 3'58.

A'LLOPHANE. A mineral of a blue,
green, or brown colour, occurring
massive, or in imitative shapes. It
is rather hard and brittle. It gela-
tinizes in acids. According to the
analysis of Stromeyer, it consists of
alumina, silica, carbonate of copper,
lime, sulphuric acid, and water.

ALL'OTEOPISM. (from aXXorpoTros, Gr.
that can be turned from one thing
into another.) A term in mineral-
ogy, as opposed to isomorphism.
A modification in the properties of
a body, not resulting from chemical
combination.

ALLO'T.

1. A mixture of different metals:
it must however be kept in mind,
that when mercury forms one of
the metals, the mixture is called
amalgam.

2. The metal of inferior value,
which is used to deteriorate, or
give new properties to, another
metal.

ALLU'VIAL. That is carried by water
to another place, and lodged upon
something else.

ALLUVIAL DEPOSITS. These consist
in the accumulation of sand, shingle,
and debris, along the sea-coast ; in
the formation of new lands on the
banks of rivers and lakes by the
alluvial depositions they carry down;
in the growth and increase of tracts
of marsh land; and in the accretion

ALL

t

ALT

of calcareous tufa. " These forma-
tions appear to have proceeded
uninterruptedly, as at present, from
the period when our continents
assumed their present form." — Rev.
J. Conyleare.

ALLUVIAL EPOCH. Some writers have
attempted, says Sir C. Lyell, to
introduce into their classification of
geological periods an alluvial epoch,
as if the transformation of loose
matter from one part of the surface
of the land to another had heen
the work of one particular period.
With equal propriety might they
have endeavoured to institute a
volcanic period, or a period of
marine or fresh-water deposition,
for alluvial formations must have
originated in every age since the
surface of the earth was first
divided into land and sea.
ALLU'VION. | (alluvia, ~L&i. alluvion,!??.
ALLU'VITJM. ) alluvione, It.) Earth,
sand, gravel, stones, or other trans-
ported matter which has been
washed away and deposited by
water upon land not permanently
submerged beneath the waters of
lakes or seas. — Lyell.

Alluvium has been divided into
modern and ancient. The modern,
characterized by the remains of
man, and contemporaneous animals
and plants; the ancient, by an
immense proportion of large mam-
malia and carnivora, both of extinct
and recent genera and species. The
term alluvium has been assigned to
the partial debris occasioned by
causes still in operation; such as
the wear produced by the present
rivers, the more violent action of
torrents, &c. The Hon. W. Fox
Strangways dates the commence-
ment of the alluvium from the
period of the retreat of the last
waters that have covered the earth,
and includes under it

1. Drift sand, marine, or inland.

2. Marsh land, composed of mud
deposited by riyer*.

3. Peat.

4. Calcareous tufa.

To these may be added beds of
gravel, produced locally by torrents
and rapid rivers. All these for-
mations are referable to causes that
are still in daily action, and they
may, by careful investigation, be
always distinguished from the gra-
vel which is strictly diluvian, as
the latter may be distinguished
from those more completely rolled
pebble beds of antediluvian origin
that occur among the regular strata
which compose the crust of our.
globe.

A'LMANDINE. A precious stone, hav-
ing some of the characters of the
garnet. Almandine is much valued
as a precious stone, its principal
colour is red of various shades,
having sometimes a tinge of yellow
or blue, or a smoky aspect. Sp.
gr. 4 '3, and it is fusible into a
black enamel. The most beautiful
are brought from Sirian, the capital
of Pegu.

A'LPINE. (alpinus, Lat.) This term
is not confined merely to the Alps,
and the things therewith connected,
but is applied to any lofty or
mountainous country, and to the
productions of elevated situations.

ALTE'HNATE. (alternus, Lat.) Being
by turns; one after another; re-
ciprocal. In botany, applied to
leaves when they stand singly on
the stem or branches, alternately
first on one side, then on the other;
to branches when placed round the
stem alternately, one above the
other ; to flowers placed in regular
succession, one above another.

ALTI'METEK. (from altus, Lat. and
perpov, Gr.) An instrument by
which the heights of bodies may be
ascertained.

ALTI'METRY. (altimitrie, Fr. alti-
metria, It.) The art of measuring
altitudes or heights, whether ac-
cessible or otherwise.

A L U

A'Luaf . (alumen, Lat. alun, Fr. allume,
It.) A triple sulphate of alumina
and potassa. Alum is both native
and factitious. The common mode
of obtaining alum is by roasting
and lixiviating certain clays con-
taining pyrites ; to the leys a
certain quantity of potassa is added,
and the triple salt is obtained by
crystallization. Alum has a sweet-
ish astringent taste. It dissolves
in five parts of water at a tem-
perature of 60°, and the solution
reddens blues.

A'LTJM-STONE. The shale from which
alum is extracted. An enormous
bed of alum-shale exists near
Whitby, in Yorkshire ; from this
bed, alum has been manufactured
ever since the days of Queen
Elizabeth. The depth to which
this stratum reaches, says Mr.
Winch, has never been ascertained,
but, to give an idea of its thickness,
I need only mention that the cliffs
at Bowdly are 600 feet high, 400
of the lower part being an entire
mass of shale ; and to what depth
it may extend below the level of
the sea, remains to be proved.
ALTJ'HINA. \ This substance obtained
A'LTJMINE. > the name of alumina
A'RGIL. ) from its forming the
base of common alum, and that of
argil from the Lat. argilla, clay, on
account of its being a constituent
of clays ; clays are termed argil-
laceous substances. It is found in
the greatest purity in corundum
and its varieties ; it is a sesqui-
oxide of aluminium. Pure argil-
laceous earth, or alumina, is a
substance which in a mixed state
is well known, but pure and un-
mixed, is one of the rarest sub-
stances in the mineral kingdom.
This earth is soft, smooth, and
unctuous, to the touch. Combined
with other earths, or rocks, it
communicates to them some of
these properties ; such rocks are
termed argillaceous. Alumina con-

L 15 ] A L U

stitues some of the hardest gems,
such as the ruby and sapphire, the
latter being crystallized alumine.
According to the analysis of Kla-
proth, the sapphire contains 95 per
cent, of pure clay. Alumina was
considered an elementary substance
till Sir Humphry Davy's electro-
chemical researches led to the
opinion of its being a metallic
oxide. Next to silicium, aluminum
would appear to be the most im-
portant base of the earths on the
face of the glode. Its collective
amount is by no means so great as
that of silicium, but it is quite as
widely spread. There is scarcely
one among the mechanical rocks
that does not contain alumina. It
constitutes the base of the various
clays, and must be regarded as a
very abundant and important con-
stituent part of rocks. It contains
46-8 per cent, of oxygen. — De la

ALTJ'MINITE. Sub- sulphate of alumine.
A white mineral, dull, opaque, and
having an earthy fracture. This
mineral occurs massive, in veins,
and in tabular and tuberose masses;
the former frequently attaining a
length of several feet, and the latter
a weight equal to three or four
pounds. It appears to have been
of stalactitical origin, and is sup-
posed to result from the decompo-
sition of iron pyrites, and the re-
action of other substances. It is
infusible at 166° of Wedgewood,
but fuses rapidly when exposed to
the stream of the hydro-oxygen
blow-pipe. According to the anal-
ysis of Stromeyer, it consists of
alumine 30, sulphuric acid 25,
water 45.

A'LTJMINOUS. Having the properties
of alum; containing alum; re-
sembling alum.

ALTJ'MINUM. The metallic base of
alumina. The metal itself has not
yet been obtained in a separate
state, but the analyses to which

A M A

alumina has been subjected have
clearly shewn that it is a metallic
oxide.

ALTJ'MOCALCITE. An earthy mineral
consisting of silica 86, alumina 3,
lime 7, and water 4. Spec, gravity
2 • 1 74. It is of a milk-white color,
inclining to blue. Practure con-
ch oidal. It adheres to the lip
when moistened. It is met with
in the clefts of iron-stone veins.

ALVE'OLAR. (alveolus, Lat.) Con-
taining sockets, pits, hollows, or
cavities.

ALVE'OLATE. Pitted or honey-combed.

ALVEOLI'NA. A genus of microscopic
foraminiferous shells.

ALVE'OLITES. (The name given by
Lamarck to a genus of corals. One
species, found in the Upper Ludlow
Rock and Aymestry Limestone, has
been named A fibrosa, by Mr.
Lonsdale.) A lapidaceous polypifer,
either incrusting or in a free mass,
composed of many concentric tables,
involving each other. The tables
are formed of tubulous, alveolar,
prismatic, short, contiguous, and
parallel cellules, connected ex-
ternally in a net- work. — Lamarck.

ALVE'OLUS. (alveolus, Lat. alveole, Pr.
alveolo, It.) A socket for a tooth ;
a small cavity or cell ; the cell of
the honey- comb.

AMA'LGAM. (from a^a, together, and
ryo/iew, to marry.) A compound of
any metal with mercury. When
two or more metals, neither being
mercury, are mixed together, the
compound is termed an alloy, but
when mercury enters into the com-
position it is called an amalgam,
and its derivation has been supposed
to be from yttaXa^/ta, or pakaaaw, to
soften, which derivation appears to
be more correct than that of John-
son, and lexicographers generally.

AMALGAMATE, (amalgamer, Pr. amal-
gamare, It.) •

1. To mix mercury with any other
metal.

16]

A M B

2. To mix any two substances
capable of uniting into one body.
AMALGAMA'TION. (amalgamation, Fr.
amalgamazione, It.)

1 . The act of mixing mercury with
other metals.

2. The act of blending different
bodies.

AMA'LTHTJS. A species of ammonite,
established by Montford.

A'MAZON-STONE. A variety of prismatic
felspar, of a blue or green colour.

A'MBER. (amlar, Arab.) A fossil
resin. For a great length of time,
various were the opinions as to the
nature and composition of amber,
but it is now well ascertained to be
a fossilized vegetable resin. It is
found in similar localities with coal
and jet. It is brittle, easily cut
with a knife, of various shades of
yellow, sometimes nearly white,
and semi-transparent : insects are
frequently found enclosed in it, and
Jussieu states that these are not
European. M. de Prance mentions
a piece of amber, about the thick-
ness of one's thumb, in which
twenty-eight insects were distinctly
to be seen, such as ants, tipula?,
small coleoptera, and a curculio.
Its constituent parts are carbon
70-68, hydrogen 11-62, oxygen
7.77. Amber is found in nodular
masses, which are sometimes eight-
een inches in circumference ; that
which is found on the eastern
shores of England, and on the
coasts of Prussia and Sicily, is
derived from beds of lignite in
tertiary strata. Fragments of fossil
gum were found near London, in
digging the tunnel through the
London clay at Highgate. In the
royal cabinet of Berlin there is a
lump of amber, discovered in Lith-
uania, weighing eighteen pounds.
Amber is one of the most electric
substances known; when submitted
to distillation, it yields an acid
sublimate, which has received the
name of succinic acid. Ten pounds

A M B

[

of ambor yield about three ounces
of purified succinic acid,
AMBERGRIS, (from amber and gris,
or grey.) A concretion from the
intestines of the physeter macro-
eephalus, or spermaceti whale. It
was long doubted of what amber-
gris consisted; and Todd, in his
last edition of Johnson's Dictionary,
retains, without any comment or
observation, the absurd opinions of
former days, stating that "some
imagine it to be the excrement of a
bird, which, being melted by the
heat of the sun, and washed off the
shore by the waves, is swallowed
by whales, who return it back in
the condition we find it." Neu-
mann absolutely denies it to be an
animal substance, as not yielding
in the analysis any one animal
principle. He concludes it to be a
bitumen issuing out of the earth
into the sea ; at first of a viscous
consistence, but hardening, by its
mixture with some liquid naphtha,
into the form in which we find it.
It is stated by Sir E. Home that
this substance is only found in the
unhealthy animal, but whether the
cause or the effect of disease is not
well ascertained. When the pieces
of ambergris are large, they are
found to contain beaks of the sepia
octopedia, or cuttlefish, the usual
food of the spermaceti whale.
Ambergris is a solid, opaque, ash-
coloured, inflammable substance,
variegated like marble, remarkably
light, its specific gravity ranging
from 780 to 926; rugged, and,
when heated, emitting a fragrant
odour. It is sometimes found in
masses of two hundred pounds
weight and upwards. It breaks
easily, but cannot be reduced to
powder; melts like wax, and is
soluble in ether and the volatile
oils, and, assisted by heat, in
alcohol, ammonia, and the fixed
oils. It has been employed in
medicine, but is now quite laid

7 ] A M B

aside. In consequence of its
fragrance, it enters into the com-
position of many articles of per-
fumery.

A'MBIT. (ambitus, Lat.) The compass
or circuit of anything ; the line
that encompasses anything.
2. In conchology, the circumfe-
rence or outline of the valves.

AMBLY'GONITE. An earthy mineral,
so* named from the Greek, in allu-
sion to the obtuse angles of its
prism. It occurs in rhombic prisms
of 106° 10' and 73° 50', rough
externally, and of a greenish white,
or sea-green colour.

AMBLY'PTERUS. A genus of fishes
whose duration was limited to the
early periods of geological forma-
tions; and which are marked by
characters that cease after the de-
position of the magnesian limestone.
This genus occurs only in strata of
the carboniferous order, and presents
four species at Saarbriick, in Lor-
raine; it is found also in Brazil.
The character of the teeth in
Amblypterus shews the habit of
this genus to have been to feed on
decayed sea- weed, and soft animal
substances at the bottom of the
water; they are all small and
numerous, and set close together
like a brush. The form of the
body, being not calculated for rapid
progression, accords with this
habit. The vertebral column con-
tinues into the upper lobe of the
tail, which is much longer than the
lower lobe, and is thus adapted to
sustain the body in an inclined
position, with the head and mouth
nearest to the bottom. This re*
markable elongation of the superior
lobe of the tail is found in every
bony fish of strata anterior to, and
including, the magnesian limestone.
— Buckland.

AMBLYRRHY'NCHUS. (from a^fiXi*?,
blunt, and p^x°9> rhynchus, snout.)
The amblyrrhynchus constitutes a
genus of lizards, established by

A M B

L

A M E

Bell, and so named from their ob-
tusely truncated head and short
snout. " The amblyrrhynchus
eristatus, (says Mr. Darwin) is ex-
tremely common on all the islands
throughout the archipelago. It
lives exclusively on the rocky sea-
beaches : its usual length is about
a yard, but some attain to four feet
long. It is of a dirty black colour,
sluggish in its movements on the
land ; but when in the water, it
swims with perfect ease and quick-
ness, by a serpentine movement of
its body and flattened tail, the legs
at this time being motionless and
closely collapsed on its sides." "On
a comparison of this animal with
the true iguanas, (says Mr. Bell)
the most striking and important
discrepancy is in the form of the
head. Instead of the long, pointed,
narrow muzzle of those species, we
have a short, obtusely truncated
head, not so long as it is broad, the
mouth, consequently, only capable
of being opened to a very short
space. These circumstances, with
the shortness and equality of the
toes, and the strong cur vat are of
the claws, evidently indicate some
striking peculiarity in its food and
general habits." Mr. Barwin says,
" I opened the stomachs of several,
and in each case found it largely
distended with minced sea-weed, of
that kind which grows in thin foli-
aceous expansions of a bright green
or dull red colour. The stomach
contained nothing but the sea-weed.
The intestines were large, as in
other herbivorous animals."

The only existing marine lizard
now known. — Lyell.
AMBLYBBR'YNCHTTS STTBCBISTATUS. A
species of lizard, thus named by
Gray. This is a terrestrial species,
confined, says Mr. Davison, to the
central islands of the Galapagos
Archipelago. "These lizards/' says
that naturalist, "like their brothers
the sea-kind, are ugly animals ; and

from their low facial angle, have a
singularly stupid appearance. The
colour of their belly, front legs, and
head, (excepting the crown, which
is nearly white), is a dirty yellowish
orange ; the back is a brownish
red, which in the younger speci-
mens is darker. In their move-
ments they are lazy and half torpid.
When not frightened, they slowly
crawl along, with their tails and
bellies dragging on the ground.

They inhabit burrows. The in-
dividuals which inhabit the lower
country, can scarcely taste a drop
of water throughout the year ; but
they consume much of the succu-
lent cactus, the branches of which
are occasionally broken off by the
wind. They eat very deliberately,
but do not chew their food. I
opened the stomachs of several, and
found them full of vegetable fibres,
and leaves of different trees, especi-
ally of a species of acacia.

The meat of these animals when
cooked is white, and by those whose
stomachs rise above all prejudices,
it is relished as very good food."
AME'NT. | (amentum, Lat.) A cat-
AME'NTUM. ) kin, one kind of inflor-
escence. "When the bracteaB on the
principal stalk are close, and over-
lap one another, or are imbricated
with the flowers sessile in their
axillae, the spike is termed an amen-
tum, or catkin, and the peduncle is
always articulated with the main
stem of the plant. Aments, or
catkins, are generally pendent,
while spikes are for the most part
erect.

A'METHYST. (apeOvffros, Gr. contrary
to wine, or drunkenness, so called,
from a supposed virtue it possessed
of preventing inebriation.) Called
also, Violet Quartz. The Gemeiner
Amethyst of Werner ; Quartz hy-
alin violet of Haiiy ; Quartz hyalin
Amethyste of Brouginart. Quartz,
coloured by a minute portion of
iron and manganese. The finest

AMI

[19]

A M M

specimens come from India, Spain,
and Siberia, but the amethyst is
commonly found in most countries.
The amethyst is a transparent gem
of a purple or violet-blue colour; it
is sometimes found naturally colour-
less, and may at any time be made
so by putting it into the fire.
When deprived of its colour, it
greatly resembles the diamond.
Some derive the name amethyst
from its colour, which resembles
wine mixed with water ; whilst
others, with more probability,
think it obtained its name from
its supposed virtue of preventing
drunkenness ; an opinion which,
however imaginary, prevailed to
that degree among the ancients,
that it was usual for great drinkers
to wear it about their necks. It
occurs massive, in rolled pieces,
in angular pieces, and crystallized.
In the massive specimens several
colours occur together. Its charac-
ters generally are those of common
quartz. According to Rose, it con-
tains silex 97*50, alumine 0*25,
oxide of iron 0'50, oxide of man-
ganese 0*25. The oriental amethyst
is a sapphire ; the green variety is
the chrysolite of some authors.

AMETHY'STINE. Possessing the pro-
perties of an amethyst ; of the
colour of an amethyst.

A'MIANTH. ] famiante, Fr. ctmianto,

AMIANTHUS, j It.) A variety of as-
bestos, or flexible asbestus ; an
incombustible mineral composed of
very delicata and minute fibres,
which were sometimes, according
to Dioscorides, worked into a cloth
capable of resisting the action of
fire. It is unctuous to the touch ;
has a shining or silky lustre ; and
is slightly translucent. Although
in mass it fuses with difficulty,
when in single fibres it melts in
the flame of a lamp.

AMIA'NTHIFOEM. Having the form or
likeness of Amianthus.

AMIANTHOID. A variety of asbcsti-
form actinolite, so named by Haiiy.
See Asbestiform actinolite.

AMMONA'CEA. According to the ar-
rangement of De Blainville, a
family of the order Polythala-
macea. It embraces the genera
Discorbis, Scaphites, Ammonites,
and Simplegas. In the Lamarckian
system the ammonacea is a family
of the order Polythalamous cephal-
opoda, embracing the genera Am-
monites, Ammonoceras, Baculites,
and Turrilites.

AMMONIA, or Volatile alkali, when
pure, is in a gaseous form. It
consists of hydrogen and nitrogen,
in the proportions of 1-76 of hy-
drogen, and 98*24 of nitrogen,.

AMMONELLIPSI'TES. A genus of fossil,
multilocular, flatly discoidal, and
eiliptically spiral shells ; the turns
contiguous and apparent on both
sides; the chambers separated by
winding septa ; the siphuncle mar-
ginal. Parkinson.

A'MMONITE. (from Jupiter Ammon.}
An extinct and very numerous
genus of the order of molluscous
animals called Cephalopoda, allied
to the modern genus Nautilus,
which inhabited a chambered shell,
curved like a coiled snake. Species
of it are found in all geological
periods of the secondary strata ;
but they have not been seen in the
tertiary beds. They are so named
from their resemblance to the horns
on the statues of Jupiter Ammon.
— Lyell.

One hundred and seventy-three
species are mentioned as having
been discovered in the oolitic group,
and upwards of three hundred have
been described. The ammonites
are a genus of shells of the class
of univalves, the characters of
which are a discoid spiral, with
contiguous turbinations all ap-
parent, and the internal parieties
articulated by sinuous sutures ;
they have also transverse parti-

A M M

r 20]

lions, lobated through their centre,
and pierced by a marginal tube.

The ammonite differs greatly
from the chambered nautilus, the
whorls, or turns, being all distinct,
and in the same plane, and the
cells very small. The family of
ammonites extends through the
entire series of the fossiliferous
formations, from the transition
strata to the chalk inclusive. M.
Brochant, in his translation of De
la Beche's Manual of Geology, enu-
merates 270 species; these species
differ according to the age of the
strata in which they are found, and
vary in size from a line to more
than four feet in diameter. The
geographical distribution of am-
monites in the ancient world, seems
to have partaken of that univers-
ality we find so common in the
animals and vegetables of a former
condition of our globe, and which
differs so remarkably from the
varied distribution that prevails
among existing forms of organic
life. We find the same genera,
and, in a few cases, the same
species of ammonites, in strata
apparently of the same age, not
only throughout Europe, but also
in distant regions of Asia, and of
North and South America. Dr.
Gerard has found at the elevation
of 16,000 feet in the Himalaya
Mountains, species of ammonites,
identical with those of the lias at
"Whitby and Lyme Eegis. The
ammonite, like the nautilus, is
composed of three essential parts :
— 1st. An external shell, usually
of a flat discoidal form, and having
its surface strengthened and orna-
mented with ribs. 2nd. A series
of internal air chambers, formed by
transverse plates, intersecting the
inner portion of the shell. 3rd. A
siphuncle, or pipe, commencing at
the bottom of the outer chamber,
and thence passing through the
entire series of air chambers to the

AMP

innermost extremity of the shell.
The most decided distinction be-
tween ammonites and nautili is
founded on the situation of the
siphon. In the ammonite, this
organ is always on the back of the
shell, but never so in the nautilus.

The opinions of geologists and
conchologists have greatly varied
as to the situation and use of the
shell of the ammonite ; Cuvier,
Lamarck, Bakewell, and others,
have supposed that the shell was
an internal one ; but the reasoning
of Buckland on this subject seems
conclusively and indisputably to
prove that the shell was external.

ADIMONITI'FEROTJS. Containing the
remains of ammonites.

AMMONO'CEEAS. | (from ammon,

AMMONOCE'EATITES. j and /ce/?as-, Gr.)
The shells of this genus resemble
ammonites in their internal struc-
ture, but that they are only curved
instead of being spirally convolute.

A'MPELITE. (from o/wreXos, Gr. a
vine.) A kind of aluminous slate,
belonging to both the fossiliferous
and metamorphic series of rocks.

AMJPHI'BIA. (from a^l and /3/os, Gr.)
A class of animals possessing the
property of living either in the
water or on dry land ; undergoing
a metamorphosis whereby the gills
become obliterated and the lungs
developed, while the heart, from
being bilocular, or possessing two
cavities only, obtains three cavi-
ties, namely, two auricles and one
ventricle.

The fourth class of the sub-
kingdom Vertebrata, kingdom Ani-
malia. In this class are com-
prised four orders, namely, Laby-
rinthodonta, Batrachia, Sauroba-
trachia, and Ophiomorpha. The
lungs of the amphibia differ greatly
from those of animals of the classes
aves and mammalia. Their body
is covered with a shell, or with
scales, or is quite naked. They have

AMP

[21 ]

AMP

neither hair, mammae, feathers, nor
radiated fins : they are oviparous
or viviparous, and are divided into
reptiles and serpents ; or reptilia
pedata, and serpentes apodes, the
former being furnished with teeth,
and the latter being destitute of
them. The amphibia possess the ex-
traordinary property of reproducing
parts, such as their legs, tails, &c.,
if destroyed.

AMpniBioLi'THirs. (from a/ufa'pio*? and
X/0os, Gr.) Fossil amphibia. The
amphibiolithi form a very large
and important class of fossils.

AMPHI'BIOTJS. (a^fa'pios, Gr. amphilie,
Fr. anfibo, It.) That partakes of
two natures, being able to live
either in the air or in the water.

A'MPHIBOLE. (aytt0t'/3*o<?, Gr.) The
name given by Haiiy, and the
French, to hornblende : for particu-
lars see Hornblende.

AMPHI'BOLITE. Any rock whose basis
is amphibole or hornblende.

AMPHIDE'SMA. (from ampJio, both and
desmos, ligament.) A genus of
bivalve shells belonging to the
family mactucea ; it is equivalve,
oval or rounded, nearly equilateral ;
hinge with one or two cardinal
teeth in each valve, and two
elongated lateral teeth distinct in
one valve, nearly obselete in the
other ; ligament separated from the
cartilage, which is elongated and
placed obliquely in an excavation
of the hinge. The separation of
the cartilage and ligament have
given origin to the name, which
signifies double ligament, an arrange-
ment of parts which distinguishes
it from Tellina. The recent species
are few, but upwards of twelve are
enumerated fossil in the British
Isles, viz., four in the crag, one in
the greensand, one in the coral
rag, one in the cornbrash, one in
the inferior oolite, and four in the
carboniferous rocks ; but we may
be allowed to express some doubt
as to the correctness of all these
identifications. — Lycett.

AMPHIPNE'USTA. The second order of
the class Arachnida, comprising
the spiders.

A'MPHIGENE. (from a/ufa and ryeVo?,
Gr.) Trapezoidal zeolite, or leucite.
This mineral, also called Yesuvian,
occurs in embedded grains or crys-
tals, in the more ancient lavas, and
is found mixed with garnet, horn-
blende, quartz, &c. in the ejected
masses of old volcanoes.

A'MPHITHEBE. | The name assign-

AMPSITHE'KITJM. j ed by Professor
Owen to a fossil genus of insectivora
found in the Stonesfield slate. This
genus differs from Didelphys, both
in the number and size of its
teeth, being smaller in size, and in
the lower jaw thirty two in number,

A'MPHISB^NA. (from afKpl <$ and fiai'vw,
Gr. to walk both ways.) The name
• given to a genus of serpents, natives
of South America.

A'MPHITJRITE. A genus of Tubicola,
of the division Articulata.

AMPHO'DELITE. An earthy mineral
described by Nordenskiold and
occurring in the limestone of Fin-
land. Its form is crystalline,
resembling that of felspar. Its
colour is a light red; fracture
uneven and splintery and posses-
sing two cleavages which meet at
an angle of 94° 19'. Specific
gravity 2-76. Hardness 4*4.

AMMPLEXICATJ'LENT. (from amplexus
and caulis, Lat.) Stem- clasping ;
embracing the stem.

AMPLE'XTJS. A singularly - formed
fossil, resembling a coral or mad-
repore, found in the Dublin lime-
stone: it is described as being
nearly cylindrical, divided into
chambers by numerous transverse
septa, which embrace each other
with reflected margins. — Sowerby.

AMPULLA'EIA. (from ampulla, Lat.)
A ventricose, subglobose, univalve,
with an umbilicated base ; tho
opening oblong and entire, with no
thickening on the left lip. The
ampullaria is a river shell of warm
climates. Its spire, which always

[22 ]

slightly projects, distinguishes this
genus from. Planorbis; and there
being no thickening on the left lip
marks it from Natica. — Parkinson.
Lamarck places the genus in the
family Peristomata, order Trachel-
lipoda. There are many species,
as the Ampullaria patula, Ampul-
laria Sigaretina, &c.

AMY'GDALOID. (apv^Sd\rj} an almond,
and eTdos, Gr. amygdalo'ide, Fr.)
A volcanic, or igneous, rock of any
composition, containing nodules of
minerals, scattered through its base,
of a roundish shape ; cellular vol-
canic rock, having its cells, or
cavities, occupied with nodules of
a dissimilar substance.

AHYGBALO'IDAL. Containing rounded,
or kernel-shaped, cavities, filled
with mineral matter of a different
character from the substance gene-
rally.

AMY'GDALYTE. Almond-stone. Of the
nature of, or resembling almonds.

A'NAL. Pertaining to the anus ; the
fin between the vent and the tail.

ANA'LCIME. A simple mineral, a
variety of zeolite, with which it
was formerly confounded ; it is
also called cubizite. It occurs
regularly crystallized in angulo-
granular concretions, and massive.
Specific gravity above 2. "When
rubbed, it acquires only a small
degree of electricity, and with
difficulty. It is composed of silica
55-07, alumina 20-22, soda 14'71,
moisture 8 '2 8. It is found, in
secondary greenstone rocks, in
various parts of Scotland, more
especially near Edinburgh. This
mineral, also called Cubizite, has
been regarded by mineralogists as
having the cube for its primitive
form. Analcime has certainly no
cleavage planes, and it must be
regarded at present as forming in
this respect as great an anomaly
in crystallography as it does in
optics by its extraordinary optical
phenomena. The most common

form of analcime is the solid,
called the icositetrahedron, which
is bounded by twenty-four equal
and similar trapezia ; and we may
regard it as derived from the cube,
by cutting off each of its angles by
three planes equally inclined to the
three faces which contain the solid
angle. The Abbe Haiiy first ob-
served in this mineral its property
of yielding no electricity by fric-
tion, and derived the name of
analcime from its want of this
property.

A'NALOGTIE. (analogue, Pr. On le fait
qutlquefois substantif. Ce sont deux
analogues.} Any body which cor-
responds with, or bears great re-
semblance to, some other body. A
recent shell of the same species
with a fossil shell, is an Analogue
of the latter. — Lyell.

ANA'MESITE. A mineral, a fine-grained
dolerite. Its colour is dark grey,
or greenish or brownish black. It
forms the intermediate step between
dolerite and basalt.

ANANCHY'TES. A helmet - shaped
echinus, a fossil of the chalk form-
ation.— Bakewell. It approaches
near to the form of Spantangus
globosus. Of the genus Ananchytes,
eight species have been determined
as occurring in the chalk deposit :
one species, ananchytes bicordatus,
has been found in the Oxford clay,
a member of the oolitic group.

ANASTOMO'SIS. (anastomose, Pr. anas-
tomoso, It. from ava and oro'^a, Gr.)
The running of vessels one into
another, or communication by in-
osculation, as of the arteries into
the veins.

ANASTOHO'SING. Communicating by
anastomosis. Applied to vessels,
threads, or fibres, which by meeting
or touching in separate points only,
form a sort of net- work, or reticu-
lation.

A'NATASE. (apaToow, Gr. extension.)
Pyramidal titanium; this mineral
is nearly of the same nature as .

AND

Titanite. It is found in Dauphiny,
Bavaria, Norway, Switzerland,
Spain, and Brazil. It is a pure
octahedral oxide of titanium. Its
colours are brown and blue ; struc-
ture lamellar ; lustre splendent and
adamantine ; it scratches glass.
Specific gravity 3-80. The Abbe
JETaiiy states the primitive crystal
of anatase to be an acute octohedron •
the common base of the pyramids
is square: the reflecting goniometer
gives the measurement 136°47'.

ANA'TIFA. A cuneiform multivalve,
composed of several unequal valves,
five or more, united together at the
extremity of a cartilaginous tube,
fixed at its base. The opening
without an operculum. — Parkinson.
The genus comprises several species.
It belongs to the class Cirrhopoda.
The anatifaa are often found ad-
hering to rocks, pieces of wood, the
bottoms of ships, &c.

ANA'TIFEB. (from anas, a duck, and
fero, to bear, Lat.) A name given
to the barnacle, or pentelasmis.
The same as Anatifa.

ANATI'NA. A genus of bivalve shells,
belonging to the family Myaria ; it
is thin, transparent, inequilateral,
transverse; hinge with a spoon-
shaped process containing the carti-
lage, and a small shelly moveable
appendage. — Sowerly. A single
species is recorded fossil in the
Oxford clay and great oolite. —
Lycett.

A^CI'LLA. \ An oblong subcylin-

ANCILLA'BIA. j drical univale, with
a short spire, not channelled : the
aperture effused, and its base slightly
notched. — Parkinson. The ebuana
glabrata, or ivory shell, belongs to
the genus Ancilla. It is found both
fossil and recent.

ANDALU'SITE. A massive mineral of
a red or grey colour ; it occurs also
crystalized. Lustre shining, glis-
tening, and vitreous. Fracture
uneven ; is easily broken. Feebly
translucent. Specific gravity 3-160.

Constituent parts, alumina 52, silica"
32, potash 8, oxide of iron 2. It
was first found in Spain ; it occurs
in gneiss in England, Ireland, and
Scotland.

A'NDESIN. (from Andes, the mineral
having been found in that mountain
range.) A variety of feldspar.

A'NDESITE. "When feldspar is of the
variety called Andesin, and the
rock contains hornblende, some
mica, and a little quartz, it is
called Andesite. — Jukes.

ANDBE'OLITE. Thus named from its
having been first found at Andre-
asberg, in the Hartz; called also
Harmotome, and, sometimes, from
form of its crystals, cross- stones.
Its crystals are two four-sided
flattened prisms, terminated by
four-sided pyramids, intersecting
each other at right angles; the
plane of intersection passing lon-
gitudinally through the prisms.
Texture foliated. Colour milk-
white. Constituent parts, silica
44, alumina 20, barytes 20, water
16. It effervesces with borax and
microcosmic salt, and is reduced to
a greenish opaque mass. With
soda it melts into a frothy white
enamel. When its powder is thro wn
on a hot coal, it emits a greenish
yellow light. — Thomson.

ANDRO'GYNOTJS. | (from avrfp and <yvvij,

ANDRO'GYNAL. j Gr.) Having two
sexes; being both male and female;
hermaphroditical. Plants bearing
male and female flowers on the
same root are thus called.

ANEMO'METEB. (from aW/^os and
peTpov, Gr. anemometre, Fr. anemo-
metro, It.) An instrument for
measuring the strength or velocity
of the wind.

ANEN'CHELUM. A genus of fossil fish,
found in the locality of Glaris, and
described by Blainville.

ANEN'TEKA. The name assigned to a
group of monads from their having
no intestinal canal. In this the
simplest form of animalcules there

H

[24]

A K I

Is but one general orifice to the
alimentary cavities, the several
stomachs opening into the buccal-
orifice.

ANEN'TEEOTJS.

An anenterous monad with a single
cavity presents the simplest form
of the digestive apparatus known
among animals.

ANGIOSPE'EMIA. (from a^ciov, a
receptacle, and ffTrep/aa, seed, Gr.)
In the artificial system of Linna3us,
an order of plants of the class
Didynamia. In a more recent
arrangement, the order Apetalee is
sub-divided into two sub-orders,
the Gymnosperms and the Angios-
perms; of the Angiosperms, the
nettle, spurge, oak, elm, &c., are
examples. In the first order, or
those having naked seeds, the plants
are mostly wholesome and aromatic
In the second, where the seeds are
enclosed in a seed-vessel, we find
the Digitalis, and other poisonous
plants.

ANGIOSPE'EMOTTS. (angiosperme, Pr.)
Belonging to the order Angios-
permia; having the seeds enclosed
in a seed-vessel.

ANGIO'STOMA. "j A family of univalve

ANGYO'STOMA. } shells, in the order
of Siphonobranchiata. It includes
many genera, as the Conus, Cypra3a,
Terebellum, &c.

ANGUI'LLIFOEM. (from anguilla, an
eel, and forma, Lat.) A term
given to fishes having the form of
an eel.

A NGUL'ITHES . A genus of multicocular
shells, possessing many of the char-
acters of nautilus, the mouth being
of a triangular form.

ANGTJ'STATE. (angustatus,~Lo.i.'] Begin-
ning with a narrow base, which
base then dilates and thickens.

A^HT'DEITE. (A substance so named
in consequence of no water enter-
ing into its composition.) The
Count de Bournon has proposed to
substitute the term Bardiglione for
Anhydrite. It is a combination of

lime and sulphuric acid, in the
proportion, according to Vauqeulin,
of 0-40 lime, and 0.60 sulphuric
acid. It has obtained various
names, as Chaux Sulfatee Anhydre,
by Haiiy ; Chaux Sulfatine by
Brongniart ; Anhydrite by Werner;
Muriacite by Poda and Klaproth ;
Pierre de Vulpino by Fleurian, and
Marno Bardiglio di Berganio by
the Italian statuaries. Anhydrous
gypsum. A variety of sulphate of
lime, called anhydrous gypsum, or
anhydrite, in consequence of its
being quite free from water. It is
harder than selenite, and sometimes
contains chloride of sodium, when
it is called muriacite. Its colours
are white, blue, red, and grey. It
occurs both massive and crystallised,.
Lustre alternates from splendent to
glistening, and is pearly. Fracture
splintery and conchoidal. Specific
gravity 2*85. There are six
varieties of this mineral.

ANHY'DEOTJS. (from a priv. and vdwp,
water.) Without water in its com-
position ; containing no water.

ANIMA'LCULE. (animalculum, Lat. ani-
malcule, JY. animaletto, It.) An
exceedingly small animal, scarcely
discoverable by unaided vision, but
which, by the help of the micros-
cope, is found both in solids and
fluids. The simplest gelatinous
animalcules, which possess no in-
ternal cavity, are reduced to super-
absorption, and thus form a transi-
tion to the mode of nourishment of
the vegetable kingdom. — Professor
Grant.

A'NKEEITE. Paratomous limestone, a
species of limestone thus named
after Prof. Anker. It is found in
the mines of Styria.

A'NIMAL KINGDOM. The animal king-
dom comprehends beings the most
diversified as to form, structure,
and the media in which they live.
The great naturalist Cuvier ar-
ranged the animal kingdom under
four great divisions, or sub-king-

A 1ST

[ 251

AND

doms, but recent authorities have
deemed it necessary to divide it
into five, splitting the Eadiata into
two, and re-arranging some of its
constituents. The five sub-king-
doms are : — 1. Yertebrata. 2. An-
nulosa. 3. Mollusca. 4. Cselenterata.
5. Protozoa. 1. Yertebrata, divided
into five classes ; namely, Mam-
malia, Aves, Eeptilia, Amphibia,
and Pisces. 2. Annulosa, divided
into seven classes, Insecta, Myria-
poda, Arachnida, Crustacea, Annu-
lata, Scolecida, and Echinodermata.
3. Mollusca, consisting of three
classes, Cephalophora, Conchifera,
and Molluscoidea. 4. Coslenterata,
comprising two classes, Actiuozoa,
and Hydrozoa. 5. Protozoa, also
containing two classes, Stomatoda,
and Astomata.

ANNE'LIDANS. | (from annellus, a small
ANNELI'DES. ) ring, Lat.) Worms
with, in general, red blood, whose
bodies are composed of rings. An-
nelida, in the classification of some
authors, constitutes the fifth class
of the animal kingdom, and com-
prises three orders, namely, Tubi-
cola, Dorsibranchiata, and Abranch-
iata. Professor Buckland observes,
"We have abundant evidence of
the early and continued prevalence
of that order of Annelidans, which
formed shelly, calcareous tubes, in
the occurrence of fossil serpulae, in
nearly all formations, from the
transition periods to the present
time." The shores of the sea, the
moist sands of coasts, as well as the
soils of all countries, are inhabited
by myriads of worms, which are
found to contain a red-coloured
fluid, circulating in veins and
arteries. These constitute the red
bloody worms of naturalists, the
" vers a sang rouge " of Cuvier.
The term annelida is most fre-
quently applied to them, from their
being surrounded by rings, extend-
ing from the anterior to the posterior
part of the body. — Professor Grant.

"Annelidans," says Mr. MacLeay,
"differ from true annulosa in being
hermaphrodite, and in general red-
blooded." All the annelidans are
not red-blooded. Mr. MacLeay
divides annelidans into two groups,
the first, or normal group, consist-
ing of marine animals, having their
body provided with distinct feet,
contains Nereidina and Serpulina ;
the second or aberrant group, Apoda,
the body being without feet or a
distinct head, comprises Lumbri-
cina, Nemertina, and Hirudina. If
the conclusion of Philippi be correct,
the shells of annelides can have no
palaeontological bearings, further
than as affording indications of the
presence of their order and class.

A'NNOLIS. An American animal, re-
sembling a lizard.

ANNITLA'BIA. A species of phalaena,
of the geometra section.

ANNTJLA'TA. In the classification by
Busk, Annulata forms the fifth
class of the sub-kingdom Annulosa,
and comprises five orders ; namely,
Polychceta, Oligochceta, Discophora,
Tardigrada, and Sagittida.

ANNULOSA. A sub-kingdom of ani-
malia, comprising seven classes,
namely, Insecta, Myriapoda, Ara-
chnida, Crustacea, Annulata, Seole-
cida, and Echinodermata.

A'NNULOSE. Furnished with rings ;
composed of rings. The annulose
animals form two great series ;
those without jointed feet, viz.,
vermes, annulosa, cirripeda ; and
those with jointed feet, namely,
insecta, myriapoda, arachnida,
Crustacea.

ANOCT'STI. The incongruous assem-
blage of fossil substances, termed
echinites, have been arranged by
Leske into two classes : the first
class is that of the anocysti, the
vent of which is in the vertex.
This class is arranged under two
divisions, Cidaris and Clypeus.

ANODO'NTA. A form of bivalvular
mollusc, with a transverse shell,

0

[26]

A K 0

having three muscular impressions ;
the hinge plain, having no appear-
ance of a tooth.

A'NOGENS. A class of plants compris-
ing two orders, the Hepaticse, or
liver- worts, and the musci, or
mosses.

ANO'MIA. A genus of molluscous bi-
valve. The anomiaa are inhabitants
of every sea, and are found ad-
hering to foreign bodies by means
of an operculum, or valve. Recent
and fossil.

ANO'MITE. A fossil shell of the genus
Anomia.

ANOMOBHOMBOI'DA. | (from avopoios,

ANOMOEHOM'BOID. ) irregular, and
pofjifioeiSris, of a rhomboidal figure.)
A genus of pellucid, crystalline
spars, of no determinate, regular,
external form, but always frac-
turing into regular rhomboidal
masses. Of this genus there are
five known species, all possessing,
in some degree, the double refrac-
tion of the island crystal.

ANOPLOTHE'EE. } (from oi/oTrXos,

ANOPLOTHE'EITJM. j unarmed, and
Oypiov, a wild beast. ) A fossil ex-
tinct quadruped, belonging to the
order Pachydermata, resembling a
pig. Five species of Anoplotherium.
have been found in the gypsum of
the neighbourhood of Paris. The
largest (Anaplotherium commune)
being of the size of a dwarf ass,
with a thick tail, equal in length
to its body, and resembling that of
an otter ; its probable use was to
assist the animal in swimming.
The posterior molar teeth in the
genus Anoplotherium resemble
those of the rhinoceros ; their feet
are terminated by two large toes,
like the ruminating animals, whilst
the composition of their tarsus is
like that of the camel. The place
of this genus stands, in one respect,
between the rhinoceros and the
horse ; and in another, between the
hippopotamus, the hog, and the
camel. — Auckland.

Cuvier has shown that the struc-
ture of the hind foot alone is
sufficient to prove, that the Anoplo-
therium was of a species at present
unknown. He divides the genus
into three sub-genera, namely, the
anoplotheria, properly so called, the
xiphodons, and the dichobunes.

The anoplotherium possesses two
characters distinguishing it from
all other animals ; feet with two
toes, in which the bones of the
metacarpus and metatarsus remain
distinct, and are not soldered to-
gether as in the ruminantia ; and
teeth in a continued series, without
any intervening gap. — Griffiths.

Professor Owen says "the anoplo-
therium appears to have been one
of the earliest forms of hoofed
quadrupeds introduced upon the
surface of this earth, and that the
ancient herbivore presents, in com-
parison with living species, no
indications of an inferior or rudi-
mental character in any known
part of its organization, and that,
with regard to its dentition, it not
only possessed incisors and canines
in both jaws, but that those teeth
were so equally developed, that they
formed one unbroken series with the
premolars and true molars, which
character is now manifested only
in the human species."

ANOPLOTHE'EIAN. Relating to the
an oplo there. The Xiphodon is a
long and slender anoplotherian
animal. — Owen.

ANOPLOTHE'EIOID. (from anoplotherium
and et£o9, Gr.) Resembling the
anoplotherium. The animal be-
longed to that group of the Anop-
lotherioid family which includes
the genera dichobune and xiphodon
of Cuvier. — Owen.

ANO'ETHITE. The mineral to which
this name is given is thus called
from the absence of right angles in
its fracture, which circumstance
serves to distinguish it. It is a
variety of felspar, and has been

ANT

[27 ]

ANT

described by Rose. Its specific
gravity is 76'3. Its constituent
parts are silica 44*49, alumina
34-4, lime 15-68, magnesia 5-3,
oxide of iron, under 1.

Anorthite is found at Monte
Somma, the ancient crater of
Vesuvius. Monticelli described
it at the same time with Rose,
under the name of Christianite,
after Prince Christian of Denmark.

ANOETHI'TIC MELANE-OBE. A species
of melane-ore, called also Allan ite,
which see.

ANTA'GONISM. Opposition of action.

ANTAGONIST, (antagonista, Lat. anta-
goniste, Fr. antagonista, It.) A term
applied to such muscles as oppose,
or counteract, others.

ANTA'BCTIC. (from avrl, against, and
a/9/cTos, the bear, or northern con-
stellation.

1. The southern pole, so called as
opposite to the northern.

2. One of the lesser circles, drawn
on the globe, at the distance of
twenty-three degrees and a half
from the antarctic, or south pole.

ANTE'CIAN. (from aWot/co?, Gr. living
opposite.) Those who live under
the same meridian east or west, but
under opposite parallels of latitude
north and south. The word is also
written Antoecian.

ANTEDILU'VIAL. | (from ante, before,
ANTEDILU'VIAN. ) and diluvium, a
deluge.)

1 . Existing before the deluge.

2. Relating to things existing be-
fore the deluge.

ANTEDILU'VIAN. One that lived
before the deluge.

ANTEMTJ'NDANE. (from ante, before,
and mundus, the world.) That
existed before the creation of the
world.

ANTE'NNJE. (antenna, Lat. antennes,
Fr. This word appears by all
lexicographers to be given in the
plural only.) Those delicate move-
able horns with which the anterior
part of the heads of insects are

furnished. These are peculiar to
this order of beings, and are easily
distinguished from the tentaculse
of vermes, in being crustaceous ;
and from the palpi of insects, by
their situation being nearer the
mouth. The antenna rarely ex-
ceed two in number, though in
some insects of the apterous kind
they amount to four, or even six.
Of the uses of the antennae we are
still ignorant.

The antennae are jointed organs,
placed one on either side of the
head between the angle of the
mouth and the eyes ; the variations
in their structure are very great.
Those which consist of equal joints
are called equal ; those whose joints
are dissimilar are called unequal.
The inequality of antennae proceeds
chiefly from the differing form of
their second and last joint. Antennae
which consist of but one joint are
called exarticulate ; those with two
joints, biarticulate ; with three,
triarticulate ; while those whose
joints are numerous are called mul-
tiarticulate. The great majority of
antennae are completely naked ;
others have a clothing consisting of
shorter or longer hair.

ANTE'BIOB. In conchology, the an-
terior of bivalves is the side opposite
to the hinge ; of a spiral univalve,
that part of the aperture most
distant from its apex ; of a sym-
metrical conical univalve, that part
where the head of its inhabitant
lies.

A'NTHER. (antkera, Lat. avOrjpa, Gr.)
That part of the flower which con-
tains the fertilizing dust, pollen, or
farina, which, when mature, it
scatters. The anther forms the
essential part of the stamen. An-
thers differ greatly as regards their
figure, number, and situation. The
most common form of the anther is
that of a grain of corn, only smaller;
it has a crease, or line, down it, as
the grain has, at which it opens

ANT

[28]

A K T

when bursting; this is generally
turned inwards towards the axis of
the flower ; but in some plants, as
the cucumber, iris, ranunculus,
&c., it is turned outwards. The
anther is generally fixed immove-
ably to the filament in various
ways ; but in most of the grasses,
and many other plants, it is at-
tached by its middle, and the
filament being very thin, it is
moved by the slightest air.

AN'THOLITE. | (from uvOos, a flower,

AN'THOLITHE. j and \iOos, a stone.)
The name applied to a fossillized
flower. It has been doubted
whether fossillized flowers are ever
met with, on the ground that the
succulent substance of the stamens
and pistils must be too delicate to
undergo the lapidifying or carbon-
izing process ; but there exist im-
pressions on shale and sandstone in
the British Museum, on viewing
which it is difficult to resist the
conviction that they exhibit some
kind of stellate blossoms. — History
of Fossil fuel.

ANTHOPHY'LLITE. (from avOos, a
flower, and 0vXXo*/, a leaf, Gr. Or,
according to others, from tbe re-
semblance of its colour to that of
the flower Anthophyllum. Its
name was assigned to it by Schu-
macher, who first described it.) A
mineral occurring both crystallized
and massive, of a yellowish grey,
or brownish colour. Its constituent
parts are, silica 54'0; alumina 3'0;
magnesia 23'0; lime 2*0; oxide of
iron 13-0; oxide of manganese
4-0. — Gmelin. Specific gravity 3 -2.
Alone, infusible before the blow-
pipe ; but with borax it yields a
grass-green transparent head. It
is the prismatic schiller-spar of
Mohs. It is found in Inverness-
shire and in Norway.

A'NTHBACTTE. (from avOpag, Gr.,
anthrax, Lat.) A shining substance
like black-lead ; a species of mineral
charcoal ; a mineral approaching to

the state of plumbago ; it consists
nearly of pure carbon, is hard to
ignite, and has frequently a semi-
metallic lustre. The coal in the
extensive coal-formation in Penn-
sylvania is called anthracite, be-
cause it emits but little smoke in
burning ; but it is only a variety
of common coal, containing but
little bitumen, and is not the true
anthracite of mineralogists. From
the same circumstance, also, it has
become a common thing to call the
"Welsh coal anthracite. In the
vicinity of some trap dikes, coal is
found converted into anthracite.
Some anthracite contains 97 per
cent of carbon. Hardness from 2'0
to 2'5. Specific gravity from 1'3
to 1-6.

AN'THBACTTIC. Partaking of the nature
of anthracite.

ANTHBA'COLITE, The same as anthra-
cite.

ANTHEA'CONITE. A variety of calca-
reous spar, of a black colour, with
a compact fracture, of a glimmering
lustre, and which, on rubbing,
yields a sulphureo - bituminous
odour.

ANTHKACOTHE'EIUH. (from avOpaKio<s,
and Orjplov, wild beast, Gr.) A
name given to an extinct mammifer,
thus named by Cuvier, supposed to
belong to the Pachydermata, the
bones of which, changed into a kind
of coal, have been found in the
lignite and coal of the tertiary
strata. This genus was first dis-
covered in the lignite of Cadibona,
in Liguria : seven species are
known, some approximating to the
size and appearance of the hog;
others approaching that of the
hippopotamus. The jaw teeth of
this extinct genus exhibited con-
siderable analogies with those of
the chaeropotamus and the dicho-
bunes. But besides that these molars
presented of themselves specific
distinctions, the large and project-
ing canines with which they were

ANT

[29]

ANT

accompanied left no doubt of the
existence of a new and distinct
genus.

Baron Cuvier considered this genus
to have held an intermediate place
between the palceotheria, anoplo-
theria, and swine.

The anthracotherium has hitherto
been found fossil only, and in strata
more recent than the chalk forma-
tion.

ANTHRO'POLITE. (from avOpwrros, a
man, and \ldos, a stone, Gr.) A
petrifaction of the human body ; a
fossil human skeleton. Several
skeletons of men, more or less
mutilated, have been found in the
"West Indies ; these still retain some
of their animal matter, and all their
phosphate of lime. One of them
may be seen in the British Museum,
and another in the Boyal Cabinet
at Paris.

from avdpwTTos, a man, and fiop<firj,
form, Gr.) Having a form resem-
bling the human : man-like.

A'STICHRONISM. (from avrl, against,
and x/aoi/o?, time.) Deviation from
the right order, or account, of time.

ANTICLI'NAL. If a range of hills, or
a valley, be composed of strata,
which on the two sides dip in
opposite directions, the imaginary
line that lies between them, towards
which the strata on each side rise,
is called the anticlinal axis. In a
row of houses, with steep roofs
facing the south, the slates repre-
sent inclined strata dipping north
and south, and the ridge is an east
and west anticlinal axis. — Lyell.

In most cases an anticlinal axis
forms a ridge, and a synclinal axis
a valley.

ANTIMO'JSTIAL. Made of antimony ;
having the properties of antimony.

ANTINO'NIATE. i A salt formed by the

ANTI'MONITE. j combination of an ti-
monic acid with a salifiable base.

A'NTIMONY. fantimoine, Fr. antimonio,
It. ) The derivation of this word is

not agreed on, some lexicographers
stating it to be from av-rl and ^ovo?,
two Greek words, signifying that
it is never found alone : Dr. John-
son, however, on the authority of
Furetiere, refers it to a ludicrous
story related by Basil Yalentine, a
German, who appears to have been
the discoverer of the metal in 1620.
It is stated that he was a monk,
and practised as a physician, and
having thrown some of it to the
hogs, he observed that after it had
purged them, they immediately
^ fattened ; imagining that the effect
on bipeds would be similar, he
administered a like dose to his
fellow monks. The experiment,
however, proved rather an unfortu-
nate one ; for, in consequence of the
dose being too large, they all died
of it, and the substance thenceforth
obtained the name of Antimoine,
i. e. Antimonk. A metallic ore,
consisting of sulphur combined
with the metal which is properly
called antimony. This metal is of
a blueish-white colour, and con-
siderable brilliancy, with a specific
gravity of 6*712. It fuses at a
temperature of 900, but requires a
greatly increased heat to volatilize
it. It is not malleable, being so
brittle as to be easily reduced to
powder by trituration, and its
ductility is inconsiderable. The
most abundant ore of antimony is
that in which it is found combined
with sulphur, and called sulphuret
of antimony. Antimony combines
with chlorine so rapidly as to
produce a shower of fire, if it be
poured, finely powdered, into a
glass jar filled with that gas. It
unites with many metals, some of
the alloys being useful. That with
lead is used for the plates on which
music is engraved. With tin it
forms a kind of pewter, and with
lead and copper it forms printer's
type metal. Native, or rhombo-
hedral, antimony occurs in metal-

A P A

[30]

A P H

liferous veins in primitive rocks in
Sweden, and in the mountains of
Hanover, Dauphiny, Hungary,
Brazil, and Mexico.

ANTI'PATHES. A genus of fixed, sub-
dendroidal polypifers, composed of
a central axis, and a corticiform,
fugacious, and deciduous crust. The
axis is flattened and fixed at its
base ; it is caulescent, subramose,
horny, solid, flexible, rather fragile,
and mostly set with small spines.
According to Parkinson, seventeen
species have been distinguished.

AN'TIPODE. (aimVoSes, Gr. antipode,
Pr. antipodi, It.) Although this
word is occasionally, and with
propriety, used in the singular,
yet it is more commonly used in
the plural number ; antipodes.

Those people who, from their
situation on the globe, have their
feet opposed directly to each other.

AN'TIQTTATED. In conchology, longi-
tudinally furrowed, but interrupted
by transverse furrows, as if the
shell had acquired new growth at
each furrow.

A'NTRTJM:. (antrum, Lat. antre, Pr.
antro, It.)

1 . A cavern ; a cave ; a den.

2. The maxillary sinus, situate
above the molar teeth of the upper
jaw.

A'NUS. (anus, Lat. anus, Pr. cmo, It.)

1. The termination downwards of
the intestinal canal.

2. In conchology, a depression on
the posterior side near the hinge of
bivalves.

AO'RTA. (aopr^, Gr. aorte, Pr. aorta,
It.) The principal artery of the
body, which arises from the left
ventricle of the heart.

A'PATITE. A genus of calcareous and
brittle earths, composed of lime
55-75 and phosphoric acid 44'25.
Apatites are white, green, blue,
red, brown, and yellow; they
occur both crystallized and massive;
Practure conchoidal and uneven;
lustre resinous. Specific gravity

3*1. The crystals are six-sided
prisms, low, and sometimes passing
into the six-sided table. One set
of varieties, in which the cleavage
is very distinct, is named foliated
apatite; another, in which the
fracture is conchoidal, is called
conchoidal apatite ; and such vari-
eties as display an uneven fracture
have obtained the name of phos-
phorite. The crystallized variety
is found, extremely beautiful, in
Devon and Cornwall.
A'PENNINES. (Apenninus, Lat.) A
chain of mountains extending
through Italy. What now con-
stitutes the central calcareous chain
of the Apennines must for a long
time have been a narrow ridgy
peninsula, branching off, at its
northern extremity, from the Alps
near Savona. This peninsula was
afterwards raised from one to two
thousand feet, by which movement
the ancient shores, and, for a cer-
tain extent, the bed of the con-
tiguous sea, were laid dry, both on
the side of the Mediterranean and
the Adriatic. — Lyell.
APE'TAL^. In botany, an order of
plants belonging to the class Exo-
gens. Apetalse are divided into
Gymnosperms and Angiosperms.
APE'TALOUS. (from a, priv. and
TreTaXoj/, a flower-leaf, or petal,
Gr.) Without flower-leaves, or
petals ; not having petals.
APE'TALOUSNESS. The state of being

without flower-leaves, or petals.
A'PEX. (Lat.) The tip or point of
any thing; the highest point of a
hill or mountain. This word
makes apices in the plural, and not
apexes.

A'PHANITE. (from a, priv. and <fraivta,
Gr., luceo.) A mineral, a variety
of amphibole.

A'PHIS. Plural, aphides. The pu-
ceron, or plant-louse. Class Insecta,
order Hemiptera. The numerous
tribes of this family of insects are
most annoying to the florist, and

API

[31 ]

A P 0

most destructive to the plants.
The best means of destroying them
is either by fumigations of tobacco,
or by watering the plants with a
week solution of the chloride of
lime. They are astonishingly pro-
lific ; they live in society on trees
and plants, of which they suck the
juices with their trunk.

A'PHRITE. (from a0^os, spuma, Gr.)
A species of stone composed of
carbonate of lime, and thus named
from its frothy, silver- white ap-
pearance.

A'pHsizriE. A variety of black
tourmaline.

APHYLLA/NTES. (from a, priv. 0vXXoi/,
a leaf, and avdos, a flower.) An
apetalous flower; a genus of plants,
class Hexandria, order Monogynia.

APHY'LLOUS. (from a, priv. and
0u\Xov, a leaf.) "Without leaves;
leafless.

APIOCKINI'TES ELLIPTICUS. The oval-
columned pear-like encrinite. A
species of Apoicrinites, thus named,
from the elliptical shape of its col-
umnar joints. It has hitherto been
found fossil only, and in a mutila-
ted state, in beds of the chalk for-
mation. Miller thus describes its
specific characters, " a crinoidal
animal, having a column composed
of oval joints articulating by a
transversely-grooved surface; the
two upper joints of the column
enlarged, sustaining the pelvis,
costa3, &c. The columns provided
with auxiliary side-arms. The
base formed by numerous irregular
columnar joints sending off fibres
for adhesion."

APIOCBINI'TES ROTTJNDUS. The round-
columned pear encrinite, so named
from the remains of the animal
possessing a pear-like form. This
Is a species of the genus Apiocri-
nites. Its specific characters are
thus stated by Miller : "A crin-
oidal animal, with a round column
composed of joints adhering by
radiating surfaces, of which from

ten to fourteen gradually enlarge
at its apex, sustaining the pelvis,
costa3, and scapulae, from which
the arms and tentaculated fingers
proceed. Base formed by exuding
calcareous matter, which indurates
in lamina?, and permanently at-
taches the animal to extraneous
bodies. The Apiocrinites rotundus,
or round-columned Pear encrinite,
has been plentifully found in the
neighbourhood of Bradford, near
Bath, and at Pfeffingen, in Ger-
many. In reference to this species
of encrinite, Professor Buckland
thus writes: " When living, their
roots were confluent, and formed a
thin pavement at this place, over
the bottom of the sea, from which
their stems and branches rose into
a thick submarine forest, composed
of these beautiful zoophytes. The
stems and bodies are occasionally
found united, as in their living
state ; the arms and fingers have
almost always been separated, but
their dislocated fragments still
remain, covering the pavement of
roots that overspreads the surface
of the adjacent oolitic limestone
rock."

APLOME. A species of the common
garnet, thus named by Haiiy, but
differing in this respect, that al-
though it commonly occurs in
rhombic dodecahedrons, its planes
are striated parallel with their
lesser diagonal. "W^iss considers
that there is no reason why this
substance should be deemed a
distinct species.

A'PODA. An order of animals be-
longing to the class Echinodermata ;
division Kacjiata. They are dis-
tinguished from Pedicellata by the
absence of the vesicular feet, which
peculiarly belong to animals of that
order.

APOPHY'LLITE. A mineral whose
constituent parts are silica 50 '76,
lime 22-39, potash 4-18, water
17*36, and a trace of fluoric acid.

APS

A R A

This substance is called also Ich-
thyoplithalmite, and Fish-eye stone.
It occurs both massive and regular-
ly crystallized. It is found in
Sweden, in secondary traprocks in
Scotland and the Hebrides, and in
Iceland, whence the finest speci-
mens are obtained.

APO'PHYSIS. (airofaffis, Gr. apophyse,
Fr.) A process of a bone, and
part of the same bone; herein
differing from ephiphysis, which is
a process attached to a bone, and
not a part of the same bone, an
excrescence.

APORRHA'IS. A genus of shells found
fossil and recent. The Aporrhais
first appears fossil in the coralline
crag epoch.

APPE'NDAGE. Something added to
another thing, without being ne-
cessary to its essence. In botany,
applied to additional organs of
plants, which are not universal or
essential ; neither is any one plant
furnished with them all. Botanists
distinguish seven kinds of ap-
pendages, namely, stipules, floral
leaves, thorns, prickles, tendrils,
glands, and hairs.

APPENDI'CULATE. Appendicled, or
appended. Applied to flowers fur-
nished with some addition distinct
from the tube ; to petioles with
leafy films at the base; to seeds
furnished with hooks, scales, &c.

APPRE'SSED. (appressus, Lat.) In
botany, applied to leaves pressed
to the Btem ; also to peduncles.

A'PSIDES. (apsides, Fr. from atyls,
Gr. The plural of apsis,) Those
two points in the orbit of a planet,
one of which is the farthest from,
and the other the nearest to, the
sun. The motion of the apsides
may be represented, by supposing
the planet to move in an ellipse,
while the ellipse itself is slowly
revolving about the sun in the
same plane. This motion of the
major axis, which is direct in all
the orbits except that of the planet

Venus, is irregular, and so slow,
that it requires more than 109,830
years for the major axis of the
earth's orbit to accomplish a side-
real revolution.

A'PSIS. (ai/r/s, Gr. apsis, Lat.) A
term used indifferently for either
of the two points of a planet's
orbit, where it is at the greatest or
least distance from the sun or
earth ; and hence the line connect-
ing those points is called the line
of the apsides. The apsis at the
greatest distance from the sun is
called the aphelion, and at the
greatest distance from the earth is
called the apogee-, while that at
the least distance from the sun is
termed the perihelion, and at the
least distance from the earth, the
perigee.

A'PTER. | (from a, priv. and •n-repbv,

A'PTERA. j a wing.) Insects which
have no wings, forming, according
to the LinnaBan system, the seventh
order of insects.

A'PTEROUS. Destitute of wings, wing-
less.

APTIEN TERRAIN. The continental
name for certain beds contempo-
raneous with the Lower Greensand
of England.

A'PULUM. The name of a metallic
substance obtained from alumina.

API'ROTJS. (from a, priv. and iri>pt Gr.
apyre, Fr.) Capable of resisting
the action of fire.

ARA'CHNIDA. | (from apd^vij and

ARA'CHNIDAN. ) e?£ov, Gr. resem-
bling a spider.) The arachnida are
members of that series of annulose
animals possessing jointed feet, and
belong to the third class of articu-
lated animals. In the animal
kingdom, the third class of annu-
losa, comprising the following
orders, namely, Pulmonata, Am-
phipneusta, Trachearia, and Pycno-
gonida/ The two great families in
the higher order of living arachni-
dans are spiders and scorpions. —
JBuckland. In the arrangement of

ARC

[33 ]

ARE

Cuvier, the arachnidans compose
the second class of articulated
animals provided with moveable
feet. They have no wings, and do
not undergo any metamorphosis,
merely casting their skin. The
majority of the arachnidans feed
on insects; some are parasitical,
living on vertebrated animals ;
others are found in flour, in cheese,
and on vegetables. Cuvier has
divided the arachnidans into two
orders, Pulmoname and Trachearise ;
the former he subdivided into two
families, Araneides and Pedipalpi ;
the latter into three families,
Pseudo-Scorpiones, Pycnogonides,
and Holetra.

AEA'CHNOID.

AEACHNOI'DES.

1. A cobweb-like membrane, form-
ing one of the tunics or coats of
the brain.

2. One of the tunics, or coats, of
the eye.

3. A species of fossil madrepore.
AEB'OEEOTJS. (aboreus, Lat.)

1. Belonging to trees, resembling
trees.

2. A term used to distinguish such
mosses, or funguses, as grow upon
trees, from those that grow on the
ground.

AEB'OEESCENCE. (from arloresco, Lat.)
The likeness of a tree, frequently
observed in crystallizations and in
mineral productions.

AEG or A CIECLE. An arc of a circle
is any part of its circumference;
and the chord, or subtense of an
arc, is a straight line joining the
two extremities of that arc.

A'ECA. A transverse inequilateral
shell: the beaks distinct; the
hinge with many teeth disposed in
a straight line. These are marine
shells. Lamarck particularizes
seven species. Pound recent and
fossil.

AECA'CEA. A genus of shells dis-
tinguished by having numerous
small penetrating teeth disposed on

both valves in a straight or bent
line.

AECA'CEA. A family of bivalve con-
chifera, according to Lamarck,
consisting of shells provided with
a linear series of teeth on the
hinge. In this family Lamarck
places the genera Area, Cucullcea,
Pectunculus, and Nucula; to which
may be added Crenella (Brown),
Solenetta (Sowerby), Myopora
(Lea), Limopsis (Sassi), Byssoarca
(Swainson), andMacroden (Lycett).
— Lycett.

A'ECTIC. | (from M/J/CTO?, ursus;

A'ECTICK. j arctique, Fr. artico It.)
Northern ; lying under the arctos,
or bear.

A'ECTIC CIECLE. One of the lesser
circles of the sphere, twenty-three
degrees and twenty-eight minutes
from the north pole. The circle at
which the northern frigid zone
begins. This and its opposite, the
antarctic, are called the two polar
circles.

A'BCTTAPUEE. The curvature of an
arch.

AEENA'CEOUS. (arenaceus, Lat.)

1. Sandy; having the properties,
or appearance, of sand.

2. Growing in sand, a term applied
to certain plants which are called
arenaceous. " The surface of the
bank is covered with various arena-
ceous plants."

A.EENA'CEOTTS QTJAETZ. Sand. There
are varieties of sand which are of
a pure white, or nearly so, as some
of the sands of Alum Bay in the
Isle of Wight, and which appear
to have resulted from the destruc-
tion of quartz.

AEEN'DALITE. The name given by
Karsten to the mineral more com-
monly known as Epidote. For
description, see Epidote.

AEENILI'TIC. Resembling sandstone;
having the quality of sandstone;
composed of sandstone.

AEEO'METEE. (from apaio<s and ^erpeuj,
Gr. areometre, Fr.) An instrument

AEG

[34]

AEG

for measuring the density or weight
of any liquid.

A'RFWEDSONITE. The name given by
Brooke, in honour of Professor
Arfwedson, to a mineral now
separated from hornblende, of
which it was wont to be deemed a
ferriferous variety. It occurs in
Greenland. Colour black; and
opaque. It contains above 35 per
cent of iron.

A'RGAL. Crude tartar, as deposited
by vinous fermentation.

ARGE'NTAL. (from argentum, Lat.)
Containing silver; combined with
silver.

ARGENTIFEROUS, (from argentum and
fero, Lat.) Producing silver.

ARGENTINA. A genus of fishes of
the order abdominales.

ARGENTINE. Slate-spar; a mineral
of a lamellated, or slaty structure ;
a nearly pure sub-species of carbon-
ate of lime.

A'RGIL. } argilla, Lat. ap^iXXos or

A'RGILL. ) a/>ryt\oe, Gr. argille, Fr.
argilla It. See Alumine.) In
1754, Margraff showed that the
basis of alum is an earth of a
peculiar nature different from every
other ; an earth which is an essen-
tial ingredient in clays, and gives
them their peculiar properties.
Hence this earth was called argill ;
Morveau afterwards gave it the
name of alumina, because it is
obtained in the state of greatest
purity from alum.

ARGILLA'CEOTJS. (argillaceus, Latin.)
Clayey; of the nature of argil;
containing argil. The rocks which
are termed argillaceous have been
all arranged into one suite, and
present the following gradation ;
clay slates, shale of the coal-
measures, shale of the lias, clays
alternating, in the oolite series,
and that of the sand below the
chalk ; and clays above the chalk.

ARGILLA'CEOUS-SCHIST. Clay slate.
An indurated clay, or shale, common
to the fossiliferous and metamorphic
series.

ARGILLIFEROUS. (from argilla and
fero, Lat.) Producing or yielding
clay.

A'RGILLITE. Argillaceous-schist, or
clay-slate. Slate is a very ex-
tensive formation, composing entire
mountains in many alpine districts.
The prevailing colours are bluish,
or greenish grey : it has a silky
lustre.

ARGI'LLOTTS. (argillosm, Lat. argilleux,
Fr . argilloso, It. ) Containing clay ;
of the nature or quality of clay.

ARGONA'UTA. The Paper Sailor ; a
genus of animals ; class Yermes,
order Testacea. An involuted uni-
valve, both recent and fossil, the
spire turning into the opening ;
very thin, with a tubercular double
dorsal keel. There are several
species, but the most remarkable
one is the Argon auta Argo, or Paper
Nautilus. " Doubts still exist
whether the Sepia found within
this shell be really the constructor
of it, or a parasitic intruder into a
shell formed by some other animal
not yet discovered. Broderip, Gray,
and Sowerby, are of opinion, that
this shell is constructed by an
animal allied to Carinaria. — BucJc-
land.

Cuvier placed argonauta among
the subgenera of Sepia, and Dr.
M'Murtrie, in his translation, says,
" These mollusca are always found
in a very thin shell, symmetrically
fluted and spirally convoluted, the
last whorl so large that it bears
some resemblance to a galley, of
which the spine is the poop. The
animal makes a consequent use of
it, and in calm weather whole fleets
of them may be observed navigating
the surface of the ocean, employing
six of their tentacula as oars, and
elevating the two membranous ones
by way of sail. If the sea become
rough, or they perceive any danger,
the argonaut withdraws all its
arms, concentrates itself in its
shell, and descends to the bottom."

ARK

[35]

A E S

ABMADI'LLO. (armaditte, Fr.) The
Dasypus of Linnseus, and placed
by him in the order Bradypoda,
class Mammalia. Cuvier has placed
the armadillo in the order Edentata,
or quadrupeds having no front
teeth, class Mammalia. The arma-
dillo is constructed with unusual
adaptations to the habit of burrow-
ing in search of its food, and
shelter in the sand ; its fore feet
forming instruments of peculiar
power for the purpose of digging ;
and presenting an extraordinary
enlargement and elongation of the
extreme bones of the toes, for the
support of long and massive claws.
The armadillo and chlamyphorus
are the only known animals that
have a compact coat of plated
armour. There are several sub-
genera.

AEI'LLUS. } (arillus, Lat.) A substance

A'EIL. ) enclosing the seed in
some plants : it is either a complete
or partial covering of a seed, fixed
to its base only, and more or less
loosely or closely enveloping its
other parts. Mace is the arillus of
the nutmeg : the red arillus of the
seed of the common spindle-tree is
well known, and is very orna-
mental in our hedges in the au-
tumn.

A'EMATUEE. farmatura, Lat. armature,
Fr.)

1. That by which the body is pro-
tected from injury.

2. Weapons of attack.

3. A piece of soft iron applied to a
loadstone, or connecting the poles
of a horse- shoe magnet,

AEME'NIAN STONE. A blue mineral, or
earth, variously spotted. It much
resembles Lapis lazuli.

AEEA'GONITE. A variety of carbonate
of lime, found originally in Arragon
in Spain, from which circumstance
it has obtained its name. Its colours
are white, grey, green, and blue ;
it is found both crystallized and
massive. It is frequently combined

with a small proportion, about four
per cent, of carbonate of strontites.
Beautiful specimens of this rare
mineral, of a snow white colour
and satin-like lustre, have been
found in the lead- mines of Cum-
berland.

ARSE'NIATE. A compound of arsenical
acid with a metallic oxide ; many
arseniates are found native ; when
heated along with charcoal powder,
they are decomposed, and arsenic
sublimes.

A'ESENIC. (apaavncov, Gr. arsenic, Fr.
arsenico, It.) Native arsenic is a
mineral found in Germany, France,
and England. It occurs generally
in masses of various shapes ; its
colour is that of blue steel ; it is
brittle ; its surface readily tarnishes
on exposure to the atmosphere.
When struck, it gives a smell
resembling garlic ; before the blow-
pipe it emits a white smoke, burns
with a blueish flame, gives a strong
garlicky smell, and deposits a white
powder. This metal and all its
compounds are virulent poisons.
Combined with sulphur it forms
orpiment or realgar, or the yellow
and red sulphurets of arsenic. The
term apaeviicov, from which the
word arsenic is derived, was an
ancient epithet, applied to those
natural substances which possessed
strong and acrimonious qualities,
and as the poisonous quality of
arsenic was found to be remarkably
powerful, the term was especially
applied to orpiment, the form in
which this metal more usually
occurred. Dr. Paris, from whose
work the above is quoted, states
that in the celebrated plague of
London, amulets of arsenic were
worn, suspended over the region of
the heart, as a preservative against
infection ; on the principle, so pre-
valent at one period, that all
poisonous substances possess a
powerful and mutual elective
attraction for each other.

ART

A'BSENITE. A name given by Fourcroy
to the combinations formed between
oxide of arsenic, or arsenious acid,
and the earths and alkalies. Ar-
senite of potassa is the active in-
gredient in Fowler's Ague Drop,
and in the Liquor Potassae Arsenitis
of the Pharmacopoeia.

ARTE'MIS. A genus of fossil shells,
found in the glacial beds of Scotland,
Iceland, the north of England, and
the Isle of Man. Recent, accord-
ing to Adamson, it ranges as far
south as Senegal, and is found,
according to Phillippi, in the Red
Sea.

A'RTERY. (from «?)/>, and ^pew, Gr.
artere, Fr. arterio, It. Thus called
because the ancients thought that
only air was contained in the
arteries.) The arteries are strong
elastic canals, which convey the
blood from the heart to the different
parts of the body, and, during life,
are distinguished from the veins
by their pulsation. The original
trunks of the arteries are two in
number, and from these all the
other arteries are derived.

AHTE'SIAN WELLS. Springs of water,
or fountains, obtained by boring
through strata destitute of water
into lower strata loaded with this
fluid, to sometimes great depths ;
thus named from its having been
first practised at Artois, the ancient
. Artesium, in France. In forming
an Artesian well, if the boring
penetrate a bed containing impure
water, it should be continued
deeper until it arrive at another
stratum containing pure water;
the bottom of the pipe being
plunged into this pure water, it
ascends within it, and is conducted
to the surface through whatever
impurities may exist in the supe-
rior strata. The impure water,
through which the boring may pass
in its descent, being excluded by
the pipe from mixing with the
pure water ascending from below.

The height to which these springs
will rise above the surface must
depend on the quantum of hydros-
tatic pressure from below ; this is
sometimes very great. The water
of an Artesian well in Roussillon
rises from thirty to fifty feet above
the surface. At Perpignan and
Tours, M. Arago states that the
water rushes up with such extreme
force as violently to eject a cannon
ball placed in the pipe. An eco-
nomical and easy method of sinking
Artesian wells has recently been
practised. Instead of the tardy
and costly process of boring with a
number of iron rods screwed to
each other, one heavy bar of cast
iron, about six feet long, and four
inches in diameter, armed at its
lower end with a cutting chisel,
and surrounded by a hollow cham-
ber, to receive, through valves, and
bring up the detritus of the per-
forated stratum, is suspended from
the end of a strong rope, which
passes over a wheel or pulley fixed
above the spot in which the hole is
made. As this rope is moved up
and down over the wheel, its tortion
gives to the bar of iron a circular
motion, sufficient to vary the place
of the cutting chisel at each descent-
"When the chamber is full, the
whole apparatus is raised quickly
to the surface to be unloaded, and
is again let down by the action of
the wheel. — BucUand.

According to the observations of
M. Arago, the greater the depth of
these wells, the higher is the tem-
perature of the waters that flow
from them. In an Artesian well
in Aberdeen, the bore is eight
inches in diameter, and 250 feet
deep, and the temperature of the
water three degrees above the
average temperature of the locality.
ARTI'CULAB,. (articularis, Lat. articu-
laire, Fr. artwolaire, It.) Belong-
ing to the joints.

ASA

[37]

A S B

ARTICTTLA'TA. The first division of
the sub-kingdom Annulosa, com-
prising four classes, namely; ID-
secta, Myriapoda, Arachnida, and
Crustacea.

AETI'CFLATED. Jointed; having joints;
united by joints. In botany, the
term articulated is applied to leaves,
when one leaflet, or pair of leaflets,
grow out of the summit of another,
with a sort of joint; to stems divided
by joints or knots, or divided from
space to space by contractions : to
culm with joints.

ARTI'CTJLATING. Fitting by means of
joints.

AETICULA'TION. (articulatio, Lat.
articulation, Fr. articolamone, It.)
The juncture or joint of bones.
There are three kinds of articulation,

1. Immoveable, called Synarthrosis;

2. Moveable, or Diarthrosis; 3.
Mixed, or Amphi-arthrosis.

ABTIODA'CTYLA. The fourth order of
the class -mammalia, and so named
from having an even number of
toes, two or four. This order
comprizes ron-ruminantia, as the
hippopotamus and pig; andrumin-
antia, as the camel, stag, sheep and
cow.

AHTICTJLO'SA. See Articulata.

ARVI'COLA AGRESTIS. The field vole.
A species of fossil rodentia, dis-
covered in the caves at Torquay
and Kirkdale.

ARVI' COLA AMPHIBIA. Thewatervole.

ABVI'COLA PKATENSIS. The bank vole.
Two species of fossil rodents, found
in Kent's hole.

AETTNDINA'CEOUS. (Lat.) Resembling
reeds.

ASUNDI'NEOTJS. | (arundinem, Latin.)

AKU'NDINOSE. ) Reedy; abounding
in reads.

ARYTJE'KOID. (from dpvraiva, a ewer,
and e^o5, resemblance, Gr.) A
name given to some of the cartil-
ages, glands, and muscles of the
larynx.

A'SAPHUS. (affcKpfc, Gr. obscurus.)
A genus of Trilobites, thus named

by Brongniart. Professor Buckland
observes, in writing of Trilobites,
"Fossils of this family were long
confounded with insects, under the
name of Entomolithus paradoxus;
after many disputes respecting
their true nature, their place has
now been fixed in a separate section
of the class Crustaceans, and al-
though the entire family appears to
have been annihilated at so early a
period as the termination of the
carboniferous strata, they neverthe -
less present analogies of structure,
which places them in near approxi-
mation to the inhabitants of the
existing seas.

The generic characters of asaphus
are thus described by Brongniart.
" Corps large et assez plat ; lobe
moyen, saillant et tres distinct.
Flancs ou lobes lateraux ayant
chacun le double de la largeur du
lobe moyen. Expansions submem-
braneuses depassant les arcs des
lobes lateraux. Bouclier demi-cir-
culaire, portant deux tubercules
oculiformes reticules ? Abdomen
divise* en huit ou douze articles."
Sir R. Murchison's Silurian system.
There are many species ; fourteen
are figured in Sir R. Murchison's
work.

In some parts of Wales, that
species of Asaphus known as A.
Debuchu, is so abundant that the
laminaB of the slates are charged
with them, so that millions of them
have probably lived and died not
far distant from those places where
we now discover them.

ASBE'STINE. Incombustible; partak-
ing of the properties of asbestos.

ASBE'STINITE. A species of asbestos.
This mineral is amorphous. Texture
foliated. Lustre silky, 3. Specific
gravity, 1-880. Colour white, with
shades of red, yellow, blue, and
green. At 150° Wedgewood, it
melts into a green glass.

ASBE'STOID. A mineral, thus called
from its resemblance to Asbestos.

A S B

[38]

ASH

It is amorphous. Texture foliated
or striated. Specific gravity from
3' to 3 '30. Colour olive or green.
It consists of silica 46, oxide of iron
25, lime 11, oxide of manganese 10,
magnesia 8.

ASBE'STOS. j ao-ySeo-ro?, Gr. nomen
ASBE'STUS. j lapidis, unde telse fiunt,
quoa non comburuntur in igni ;
asleste, Fr. asleste, It.) A mineral
of which there are several varieties,
all marked by their fibrous flexible
quality. Asbestos is itself a variety
of hornblende. It was well known
to the ancients, by whom a kind of
cloth was made of one of its varie-
ties, which was esteemed to be
incombustible. It is found abun-
dantly in most mountainous coun-
tries, and in the isle of Anglesea
it lies in considerable quantities
between the beds of serpentine.
Yeins of asbestus may be seen in
almost all the serpentine formation
of the Lizard ; some of them are as
wide as half-an-inch ; but their
width, in general, is that of a line,
running in all directions. Veins
of asbestus occur also in the green-
stone. Although fire acts slowly on
its fibres, yet it will, in the course
of time, consume them. It is
commonly amorphous. Texture
fibrous. Lustre from 0 to 2.
Hardness from 3 to 7 . It absorbs
water. Colours white, green, blue,
yellow, and brown. Its constituent
parts are, silica 60, magnesia 30,
lime 6, alumina 4. It feels soapy
or greasy. For one of its varieties,
flexible asbestos, see Amianthus.
Another variety has obtained the
name of mountain cork, from its
swimming when thrown into water.
This variety has a strong resemb-
lance to common cork. Its fibres
are interwoven. Specific gravity
from 0-6806 to 0-9933. It feels
meagre ; yields to the fingers like
cork, and is somewhat elastic.
Colour white or grey. Its con-
stituent parts are, silica 62, car-

bonate of magnesia 23, carbonate
of lime 12, alumina 2*7, oxide of
iron 2 -3. One variety is called
rigid or common asbestos. Of this
the colours are usually green, and
disposed in straight, pearly, rigid
fibrous concretions. Soapy or unc-
tuous to the feel. Another variety
is known by the names of rockwood,
mountainwood, or ligneous asbestos.
The colour of this variety is brown,
and its general appearance greatly
resembles fossil wood.

ASBE'STIFOKH ACTYNOLITE. j A sub-

ASBE'STOUS ACTYNOLITE. ) species
ofcvariety of the mineral actynolite,
of a green, greenish-grey, or brown-
ish-green colour. It occurs in beds
in gneiss, mica slate, and granular
limestone. Specific gravity 2-5 to
2-8 Those varieties of asbestiform
actynolite which occur in very thin
scopiformly aggregated acicular
elastic flexible crystals, have by
some mineralogists been deemed a
distinct species, and named, by
Saussure, Byssolite, by Haiiy,
Amianthoid, and by others, As-
bestoid.

A'SCARIS. (afficapl?, Gr.) Cuvier
placed the ascaris in the order
Xematoidea, class Entozoa. The
thread- worm.

ASCI'DIA. A genus of animals found
in the sea, adhering to the rocks.
Class Vermes, order Mollusca.

ASCI'DIOIDA. Having the characters
of ascidia; resembling ascidia.
Just as we see the ascidioida and
helianthoida of our seas fixed to the
boulders and rocky skerries. — Hugh
Miller.

Ascidioida, or Tunicata, con-
stitutes the third order in the class
Molluscoidea ; these have EO fossil
representative's, as they have no
hard parts likely to be preserved.
ASCITI'TIOUS. (ascititius, Lat.) Sup-
plemental; additional; not origin-
ally forming part of.

ASHBUENHAM BEDS. The lowest

division of the "Wealden strata,

ASS

[39]

AST

consisting of inferior limestones
and shale. Dr. Mantell states the
Ashburnham beds to consist of a
series of highly ferruginous sands,
alternating with clay and shale,
containing ironstone and lignite;
and shelly limestone, alternating
with sandstone, shale, and marl,
and concretional masses of grit.
The organic remains consist of ferns
and carbonized vegetables ; cypris ;
shells of cyclas and cyrena; and
lignite.

A'SHLAR. A name given to freestone
as it is taken from the quarry.

ASIPHONIBRANCHIA'TA. In De Bj^in-
ville's system, the second order of
the class Paracepholophora Dioica,
comprising the genera Goniostomata,
Cricostomata, Hemicyclostomata,
Ellipsostomata, and Oxystomata.

A'SPHALT. 1 (a<r0a\TosGrr. bitumen,

ASPHA'LTOS. > asphalte, Fr.) A bit-

ASPHA'LTTTM. ) uminous substance,
found abundantly on the shores of
the Dead Sea; in the island of
Trinidad, in China, America, and
various parts of Europe. Its colour
is brown or black; it is lighter than
water, and easily soluble in naphtha,
but quite insoluble in water. Frac-
ture conchoidal. Brittle. Feels
smooth, but not unctuous. Does
not stain the fingers. On the sur-
face of the Dead Sea it is found
floating in a state of liquidity, but
exposure to the air soon renders it
hard. It melts easily when heated,
and, if pure, burns without leaving
any ashes.

ASPEBG'ILLTJM. A genus of bivalve
shells of the order tubicola. The
Serpula penis of LinnaBus.

ASPIDOBHY'NCHUS. The name given
to a fossil Sauroid fish from the
lime stone of Solenhofen. An ex-
ample of this is given by Professor
Buckland in his Bridgewater Trea-
tise, pi. 27 a, fig. 5.

ASSA'Y. The operation of determining
the proportion of precious metal
contained in any mineral or metal-

lic compound, by analyzing a
portion thereof.

A'STACTD. | The craw-fish, or lobster;

A'STACTTE. j a genus of the family
Macroura ; it is divided into four
sections, each consisting of many
subgenera. The lobster, crab, craw-
fish, prawn, and shrimp are in-
cluded.

A'STACTJS. (from a^ra^o?, Gr. astacus,
Lat.) The lobster or craw-fish.

ASTA'COLITE. (from a<rraKo<? and \iOo?f
Gr.) Fossil or petrified craw- fish,
or lobster.

ASTA'ETE. (from the Sidonian god-
dess ; the Crassina of Lamarck.) A
genus of bivalve shells; equi valve,
inequilateral, thick, compressed ;
hinge with two large diverging
teeth in the right valve, one in the
left ; ligament external. The spe-
cies are numerous, more especially
the fossil ones ; forty- six are enu-
merated in Morris's catalogue of
English fossils, and many others
have not been described. — Lycett.

ASTE'EIA. fasterias, Lat. asUrie, Fr.)
A variety of sapphire, or bastard
opal.

ASTE'BIA. (from a<nrfp, Gr. a star.)
The star-fish, or sea-star, a genus
of animals, class Yermes, order
Mollusca. These animals have
their mouth in the centre, and.
placed downwards ; from their
bodies five or more rays, or arms,
are given off, furnished with nu-
merous retractile tentacula. They
have the power of reproducing
their rays if destroyed. They are
all inhabitants of the sea, and they
are frequently found fossil, in great
perfection, in the chalk. Some-
remarkably fine impressions have
been discovered in flint. The whet-
stone of Devonshire affords similar
remains. Linnaaus has placed them
in the order Pedicellata, class Echi-
nodermata.

Two species of this genus of
radiata have been found fossil in
the chalk, one of which has been

A s

[ 40]

AST

named by Goldfuss A. quinqueloba,
the other has not yet been deter-
mined. Eight species found in the
oolite of Germany have been thus
named by Goldfuss, Munstcr, and
Schlotheim, A. arenicula, A.juren-
sis, A. lancelota, A. lumbricalis,
A. prisca, A. scutata, A. stellifera,
A. tabulata. Of the Linnaean
genus Asteria, M. Lamarck has
formed a family to which he has
assigned the name Stellerida, com-
prehending four genera.

ASTE'RIATED. Radiated.

ASTE'RIALITE. (from atnyp, and \i'6o<?,
Gr.) Fossilized, petrified, or silici-
fied asterias, or star- fish.

ASTE'RID^;. ( The fourth order of the

ASTERID'EA. ( class Echinodermata,
comprising the star-fish, &c.

A'STERITE. \ (astroite, Er. Espece de

A'STRAITE. / madrepore ou de corps

A'STRITE. i marin, aur lequel on

A'STROITE. j voit represente la figure
d'une etoile.) Star stone.

This name is also given to certain
varieties of the perfect corundum.

A' STEROID, (from ao-T^/3 andetSo?, Gr.)
The name assigned by Herschel to
some newly discovered planets.

ASTERO'IDAL. Resembling a star-fish.

ASTEROLE'PIS. A genus of ichthyolites
of the old red sandstone, known
also as chelonichthys, which latter
name has now been supplanted by
the former. Many species have
been described by Agassiz.

ASTEROPHY'LLITE. (from a<m}/> and
<fiv\\ov, Gr.) A plant discovered
in the coal formation, and thus
named from the stellated disposition
of the leaves around the branches.

ASTO'MATA. The second class of the
sub-kingdom Protozoa, comprising
the four orders, Spongiadse, Eor-
aminifera, Thalissicolidse, and Gre-
garinidae.

ASTRE'A. A genus of saxigenous
polyi. The appearance of groups
of astrece, and other corals, is de-
scribed as being most beautiful
when viewed with the animals

alive and in activity; looking down
through the clear sea-water, the
surface of the rocks appears one
living mass, and the polypi present
the most vivid hues.

It is stated, by those who have
opportunities of observing, that the
species of saxigenous polypi which
constantly form the most extensive
coral reefs and islands belong to
the genera Meandrina, Caryophyllia,
and Astrea, but especially to the
latter; and that these are not found
at depths exceeding a few fathoms.
M. M. Quoy and Gamard observe,
that neither with the anchor nor
the lead, have they ever brought
up fragments of astrea3, except
where the water was shallow, about
twenty-five or thirty feet in depth,
though they found that the branched
corals, which do not form solid
masses, lived at great depths.

Fifteen species of the genus
Astrea have been determined by
Goldfuss as met with in the mem-
bers of the chalk group : twenty-
four species also are described as
found in the oolite : one belongs to
the muschelkalk, namely, Astrea
pediculata: one species, A. undulata
has been found in the carboniferous
limestone : three species have been
discovered in the grauwacke.

Parkinson thus describes the
genue Astrea : "A stony polypifer,
fixed, conglomerated, incrusting
other bodies, or formed in a sub-
globose but rarely lobated mass.
The upper surface set with sessile,
lamellated, round or subangular
stars, which are circumscribed.
The stars in this genus are circum-
scribed. The substance is never
raised in extended expansions, or
developed in leaves, as in the
Explanarice, or ramified like the
Madrepores" The same author
describes 31 species.
ASTRI'FEROUS. j Bearing stars; having
ASTRI'GEROTJS. } stars; carrying stars.
A'STRITE. See Asterite.

ATM

[41 ]

A T

ASTROITE. See Asterite. A name
given by some writers to corals of
the genus Astrea.

ATA'CAMITE. Prismatoidal green mala-
chite. Native muriate of copper,
of a green colour, occuring both
massive and crystallized. It con-
sists of oxide of copper 76 "6,
muriatic acid 12 '4, water 12. It
has obtained its name from having
been found in alluvial sand in the
river Lipas, in the desert of Atacama
in Peru. It has also been found in
some of the Vesuvian lavas. The
primitive form is an octoedron. It
is the Cuivre muriate of Haiiy.

ATMO'METER. (from ar^o?, vapour,
and yM-fc-Tyoe'o), to measure, Gr.) An
instrument contrived by Professor
Leslie, for ascertaining the quantity
of moisture exhaled from a damp
surface in a given period.

ATMOS'PHKRE. (from ar/to?, vapour,
and a<paipa, sphere, Gr. atmosphere,
Fr. atmosfera, It.) The gaseous
compound which surrounds the
earth : it is a thin, transparent,
invisible, and elastic fluid, essen-
tially composed of oxygen and
nitrogen, yielding by analysis 79
parts of nitrogen to 21 of oxygen,
and containing in every 1000 parts
three or four of carbonic acid gas.
These proportions are found to be
the same at all heights hitherto
attained by man. The atmosphere,
from its powers of refraction, has
been calculated to extend upwards
about forty-five miles. That the
atmosphere is a ponderous bod}^
was first suspected by Galileo, who
found lhat a copper ball, in which
the air had been condensed, weighed
heavier than when the air was in
its ordinary state of tension. The
fact was afterwards demonstrated
by Torricelli, whose attention was
drawn to the subject by the attempt
of a well digger to raise water by a
sucking pump to a height exceeding
33 feet.

The pressure of the atmosphere
is about fifteen pounds on every

square inch ; so that the surface of
the whole globe sustains a weight
of 11,449,000,000 hundreds of
millions of pounds. Shell-fish
which have the power of producing
a vacuum, adhere to the rocks by a
pressure of fifteen pounds upon
every square inch of contact.

When in equilibrio, the atmos-
phere is an ellipsoid flattened at the
poles, in consequence of its rotation
with the earth.

The barometer, by its fall and rise,
indicates a corresponding change in
the density of the atmosphere. At
the surface of the earth the mean
density or pressure is considered
equal to the support of a column of
quicksilver 30 inches high ; at 1000
feet above the surface of the earth
the column of quicksilver is found
to fall to 28*91 inches; at one mile
to 24'67 inches; at two miles to
20*29 inches; at three miles to
16'68 inches; the density decreas-
ing upwards in geometrical pro-
gression. The air even on moun-
tain tops is sufficient to diminish
the intensity of sound, to effect the
breathing,- and to produce a loss of
muscular power. The greatest
elevation attained by man, is 4'36
miles; that height M. M. Gay-
Lussac and Biot ascended in a
balloon, but they suffered severely
from the rarity of the atmosphere.

A'TOLL. The name given to a ring-
formed coral reef.

ATRY'PA. (from a, priv,, and rpwra,
a foramen, Gr.) A genus of fossil
shells found in the Lower Siluvian
Bocks. A sub-division of the
family of Terebratula. "This
genus is divided from Spirifer, and
includes those species which have
a short hinge line without a large
area, and are either destitute of a
foramen or possess only a small
triangular one. They are rounded
shells, and are not furrowed like
the typical species of Spirifer.
The species of this sub-division
have generally been described as

A U R

[42]

A U T

Terebratulse by British authors,
but they have acute, not perforated
beaks." — Sir R. Murchimon. Sil-
urian System.

ATTENUATED, (attenuaius, Lat. attenue,
Fr.) Thin; slender; tapering. An
epithet for a leaf tapering at one or
both extremities.

AU'GITE. (av^rj, Gr. splendour.) A
mineral of a dark green, brown, or
black colour, found in volcanic
rocks. It is the Pyroxene of Haiiy,
the Paratoma augit of Mohs, and
the augit of Werner. Its fracture
is conchoidal and uneven. It gene-
rally crystallizes in six or eight-
sided prisms, terminated by dihedral
summits. It is commonly attracted
by the magnet. Scarcely fusible
by the blow-pipe. With borax it
. melts into a yellowish glass, which
while hot appears red. There are
many varieties of augite, as the
Diopside, Musite, Alalite, Sahlite,
Pyrogome, Fassaite, Malacolite,
Common Augite, Conchoidal Augite,
Granular Augite, Coccolite and
Amianthus. Augite consists of
silica 52, lime 13, protoxide of
iron and manganese 16, magnesia
10, alumina 9.

ATTGI'TIC PO'EPHYEY. A rock with a
dark grey, or greenish, base, con-
taining crystals of augite and
Labrador felspar.

ATJLO'POHA. The name given by
Goldfuss to a genus of corals. Pour
species are described as found in
the Wenlock Limestone. Three of
them have been named by Goldfuss,
namely, A. conglomerata, A. serpens,
and A. tubseformis ; the fourth A.
consimilis has been described and
thus named by Mr. Lonsdale.
Species of the genus Aulopora are
found in other strata.

ATJ'EATED.

1. Resembling gold.

2. Eared ; having ears, as in the
scallop-shell.

ATJEE'LIA. The first change of the
eruca, or maggot, of any kind of

insect; a chrysalis, having a golden
hue, previous to its becoming the
perfect insect.

AU'EICLE. (auricula, Lat.)

1. That part of the ear which is
prominent from the head.
1. A cavity of the heart. The
heart is divided into four cavities,
or chambers, namely, two auricles
and two ventricles.

ATJ'RICLED. Having ears; having
appendages resembling ears; ap-
plied to leaves when they are
furnished with a pair of leaflets,
generally distinct, but sometimes
joined with them.

AUEI'CULA. An ovate or oblong pyra-
midal marine univale, with the
spire extruded : the opening entire,
oblong, and narrowed upwards; the
columella plicated, with different
plicaB in the opposite lip. Lamarck
has placed those shells whose open-
ings are entire, but whose columella3
are plicated, under this genus,
Auricula. — Parkinson. Possil auri-
culaa occur in the chalk marl and
in the Shanklin sand. Seventeen
species have been recorded \)j
Deshayes : of many species re-
corded from the neocomian rocks of
Prance, the genus is doubtful.

ATJEI'CTJLATE. Ear-shaped.

ATJ'EIFOEM. (from auris and forma,
Lat.) Having the form of an ear;
in the shape of an ear; the haliotis
is an example.

ATT'STEAL. } (australis, Lat. austral,

AU'STEINE. j Pr. australe, It.) South-
ern ; southward.

AUTO'MALITE. (Octahedral corundum
of Mohs. Spinelle zincifere of
Haiiy. The Automolith of Werner ;
sometimes also called Gahnite, from
Gahn, its discoverer. The name
automalite was given to it by
Eckeberg.) A variety of corundum
containing oxide of zinc. It occurs
imbedded in talc, and associated
with lead-glance. It is crystallized
in regular octahedrons, or in tetra-
hedrons with truncated

A V E

A X 1

Automalite is placed by some
mineralogists in the ruby family;
by others it is considered to be a
variety of spinel, and from the
large quantity of oxide of zinc
which enters into its composition it
has been termed zinciferous spinel.
Externally it is glistening ; lustre
pearly, inclining to semi-metallic.
Internally it is shining on the
principal fracture, but glistening
on the cross fracture, and the lustre
resinous. Fracture foliated, ex-
hibiting a four- fold cleavage parallel
with the planes of the octahedron.
It is heavier than spinel, its specific
gravity being 4'1 to 4'3, from which
it also differs in being nearly opaque,
and of a dark bluish-green colour
by transmitted light. It is of
sufficient hardness to scratch quartz.
It is brittle and easily frangible.
Before the blow-pipe it is infusible.
It is a non-conductor of electricity.
Its constituent parts are alumina,
ths oxides of zinc and iron, silica,
and sometimes magnesia. It has
been found in America and in
Sweden.

AUTO'MOLITE. See Automalite.

A'VALANCHE. (avdlange, ou avalanche,
Fr.) A mass of snow which,
detached from any mountainous
height, by rolling onwards accu-
mulates frequently prodigious bulk
and acquires great momentum.
Avalanches are in mountainous
countries productive of the direst
misfortunes, sweeping before them
in their irresistible and destructive
progress every impeding object;
breaking off large masses of rocks,
uprooting, or tearing away, the
noblest trees, damming up river
courses, and burying beneath their
volumes villages, with their whole
population.

A v' AN TURIN E. | Quartz Hyalin Aven-

AY'ENTTJRINE. j turine of Haiiy. A
variety or sub-species of quartz,
exhibiting numerous points or spots
that glitter like gold. This appear-

ance is generally owing to the
intermixture of small laminae of
mica; in some instances it is caused
by reflexion from numerous small
rents or fissures, in the stone. The
name is said to be derived from the
French, par avanture ; a workman
having first found it by accident.

AVELL'ANA. A genus of shells for-
merly attributed to Auricula, oc-
curring in the Lower Chalk of
Lyme Regis, the Gault of Folkstone,
and in the Greensand.

A'VES. The second of the sub-king-
dom vertebrata, comprising eight
orders of birds.

AVER'TEBRATE. Having no vertebrae;
destitute of vertebrae.

AVI'CULA. (from avis, Lat.) A genus
of inequivalved, fragile, rather
smooth bivalves; the base trans-
verse and straight, with produced
extremities and caudiform an-
teriorly; the left valve notched;
the hinge linear; with a tooth in
each valve beneath the beaks ; the
ligamental area marginal, narrow
and grooved, not traversed by the
byssus. — Parkinson. Many species
of auricula have been recorded from
the Neocomian rocks of France, but
the genus is doubtful. — Lycett.

AXE-STONE. A mineral found in New
Zealand and the islands of the
Pacific, and by the inhabitants
made into axes and other cutting
instruments, from which circum-
stance it has obtained its name.
It is a sub-species of jade, and in
many respects resembles nephrite,
or nephritic stone. See Jade.

AXI'LLA. (axilla, Lat.)

1. In anatomy, the arm-pit.

2. In botany, the angle formed by-
the stalk of a leaf with the stem.

AXI'LLARY. (axillaris, Lat. axillaire,
Fr.)

1. In botany, applied to peduncles
when proceeding from the angle
made by the leaf and stem, or
branch and stem ; also to flowers,

A X I

[44]

ATM

and to spikes of flowers, proceeding
from either of the above situations.

2. In anatomy, pertaining to the
axilla, or arm-pit.

3. In entomology, applied to parts
which spring from the point of
union of two other parts.

A'XINITE. The thumerstein or thu-
merstone of Werner. It has ob-
tained the name of axinite in
consequence of the axe-like shape
of its crystals. Its colours are
brown, grey, black, and blue. The
name of thumerstein was given to
it by "Werner, from its having been
found near Thum, in Saxony. It
occurs massive, often disseminated,
but most generally crystallized.
Specific gravity from 3-21 to 3-29.
Hardness = 6-5 — 7-0. The
crystals are sometimes tabular, and
are often so arranged as to form
small cells. It is transparent or
translucent, sometimes at the edges
only, or is quite opaque. Some-
times one part of a crystal is violet
and nearly transparent, while the
other is green and nearly opaque.
Texture foliated. Fracture con-
choidal. Before the blow-pipe it
froths like zeolite, and melts into a
hard black enamel. It has been
found sparingly in Cornwall, but
in no other part of Great Britain.
A specimen analysed by Vauquelin
was found to consist of silica 44,
alumina, 18, lime 19, oxide of
iron 14, oxide of manganese 4.

Some of the porphyritic rocks of
Cornwall, says Dr. Boase, are very
beautiful, having a violet coloured
basis, which appears to be occa-
sioned by the compact felspar pass-
ing into massive axinite; for the

• latter mineral, in crystals, fre-
quently occurs in small irregular
veins, which traverse . this rock,
after the manner of calcareous spar
in limestone.

A'XINITIC. (from axinite.} Contain-
ing axinite.

A'XINUS. A fossil genus of bivalve
shells, described by Sowerby as

equivalve, transverse ; posterior
side very short, rounded, with a
long ligament placed in a furrow,
extending along the whole ridge;
anterior side produced, angulated,
truncated, with a fLattish lunette
near the beaks. One species has
been recorded in the London clay,
four in the new red sandstone, one
in the magnesian limestone, and
one in the carboniferous shale. —
Lycett.
A'xis. (axis Lat.)

1. The line, real or imaginary, that
passes through anything on which
it may revolve.

2. In botany, the imaginary central
line of different parts of a plant,
round which leaves, or modified
leaves, are produced. The stem is
also so called, for this reason.

AXO'TOMOUS. (from agtov, and re/ti/w,
Gr.) A mineralogical term, signi-
fying cleavable in one particular
direction.

A'YHESTRY LIMESTONE. So named
from the village of Aymestry,
where it laid open. One of the
sub-divisions (the central) of the
Ludlow rocks. A sub-crystalline
grey or blue argillaceous limestone,
a marine formation.

This sub-division of the Ludlow
rocks, says Sir R. Murchinson, is,
in the neighbourhood of Aymestry,
arranged in beds of from one to
five feet thick, dipping to the south
and south-east at slight angles; the
laminaB of deposit being marked by
layers of shells, and sometimes of
corallines. When quarried into,
the rock is of an indigo or bluish
grey colour, in parts mottled by
the mixture of white carbonate of
lime, both crystalline and compact.
In nearly all the quarries between
Norton Camp and Aymestry, the
rock is charged with a profusion of
that remarkable shell called Penta-
merus Knightii. This species is
confined almost exclusively to the
limestone of this sub-division. The
following fossils also characterise

A Z 0

[45]

BAG

the calcareous zone: Lingula
Lewisii; Terebratula Wilsoni;
Bellerophon Aymestriensis ; Avi-
cula reticulata ; and the coral
Favosites Gothlandica.

The Aymestry Limestone differs
in lithological aspect and useful
properties, from any under or over-
lying calcareous rocks, being much
less crystalline and pure than the
mountain or carboniferous lime-
stone, and inferior in quality to
the lower limestone of Wenlock.
Its earthy character renders it of
very great value as a cement,
particularly in subaqueous opera-
tions, the mortar formed of it
setting rapidly under water. — Sir
R. Murchinson. Silurian System.
Azo'ic. (Destitute of animal remains.)
Those rocks in which no remains of
animal existences have been dis-
covered.

A'ZOTE. (from a, priv. and guy, life,
Gr.) A constituent part of the
atmosphere, receiving its name
from its fatal effects on animal life.
It is now usually called Nitrogen,
which see.

AZO'TIC. Consisting of azote; re-
sembling azote in its properties;
destructive of life.

A'ZUEITE. Another name for Lazulit
or Lazulite ; a combination of
phosphoric acid, alumina, magnesia
and water. Primary form a right
rhombic prism of 121° 3V.

A'ZURE STONE. Lapis Lazuli; the
Lazurstein of Werner, and Lazulite
of Haiiy. A mineral consisting of
silica, alumina, lime, oxide of iron,
soda, magnesia, and sulfuric acid.
Specific gravity 2 95. The finest
specimens come from China, Persia,
and Siberia.

B

B'ABLNGTONITE. An earthy mineral,
so named by Levy, in honour of
Dr. Babington. It occurs in
distinct crystals at Arendal in
Norway. It is of a dark, greenish
black colour.

BA'CCA. (bacca, Lat.) A fruit; a
berry.

B A cci' FERGUS, (from bacca, a berry,
and fero, to bear, baccifere, Fr.)
Berry-bearing ; that produces
berries.

BA'CULITE. (from baculus, Lat. So
named from its resemblance to a
straight staff.) A fossil, straight
chambered, conical, elongated and
symmetrical shell, depressed later-
ally, and divided into numerous
chambers by transverse, sinuous,
and imperfect septa ; the articula-
tions, or sutures, being indented in
the manner of the battlements of a
tower. The external chamber is

considerably larger than the rest,
and capable of containing a con-
siderable portion of the animal.
Five species, namely, Baculites
Faujasii, B. obliquatus, B. verte-
bralis, B. anceps, and B. triangu-
laris, are described as occuring in
the cretaceous group. Sir H. De
La Beche says, it was once con-
sidered that the genus Baculites
was confined to the cretaceous
group, but, though more abundant
in it than in any other series, it is
not thus limited. The remains of
baculites have been hitherto found
in the chalk formation only, and
the baculite appears to have become
extinct simultaneously with the
last of the ammonites, at the
termination of the chalk formation.
This fossil may be seen beautifully
figured in Professor Buckland's
Bridgewater Treatise.

J8 A L

BAB,

BAG' SHOT BEDS. } One of the groups of

BAG'SHOT SAND, j the Eocene deposits
in the London basin. These Eocene
deposits have generally been divided
into three groups, namely, the
plastic clay, the London clay, and
the Bagshot sand. Of these, the
Bagshot sand is the uppermost, in
the order of superposition,: it rests
conformably upon the London clay,
and consists of siliceous sand and
sandstone, without any cement,
with some thin deposits of marl
associated. The sandstone of the
Bagshot sand is so hard as to
require blasting with gunpowder,
and is used for paving and building.
"Windsor Castle is constructed of it
This deposit is destitute of mineral
contents.

BAI'KALITE. A variety of augite, of
a whitish, or yellowish white, and
pale green colour.

B'ALA LIMESTONE. A group of a few
beds found in North Wales, rarely
exceeding twenty feet in thickness.

BA'LANITE. (lalanites, Lat.) A fossil
belonging to the genus balanus.

BAI/ANTJS. (balanus, Lat. fiaKavo^,
Gr.) A sessile, affixed, conical
univalve, the apex truncated; the
base closed by an adherent testa-
ceous plate; the opening subtrigonal
or elliptical, with four moveable
valves, inserted near the inner base
of the shell. The balani are not
to be considered among those fossils
which are frequently found. —
Parkinson.

The recent balanus is observed
on rocks and shells at a depth
ranging to ten fathoms ; and affixed
to bottoms of ships and other float-
ing bodies. — De La Heche,

Balanus is the only genus of
sessile cirrhipedes, the shells of
which consist of six principal
valves, except Coronula, — Sowerby,

BA'LASS. } (Called also Spinel and

BA'LLASS. j Zeilanit by "Werner.) A
sub-species of corundum; it is
found in crystals of a regular

octahedron, composed of two four-
sided pyramids applied base to base.
Colour red. Balass is chiefly found
in Ceylon, and the dark and black
varieties have obtained the name
Ceylanite. It ranks among 'the
precious stones, and when of a
certain size is deemed very valuable.

BALI'STES. The file-fish; a cartila-
ginous fish belonging to the fourth
class. Professor Buckland, in his
chapter on Ichthyodorulites, or
fossil spines, states that the spines
of balistes have not their base, like
that of the spines of sharks, simply
imbedded in the flesh, and attached
to strong muscles; but articulate
with a bone beneath them. The
spine of balistes is also kept erect
by a second spine behind its base,
acting like a bolt or wedge, which
is siinultaneouslv inserted or with-
drawn by the same muscular motion
that raises or depresses the spine.

BA'LKSTONE. A provincial name given
to an impure stratified limestone.

BA'NNER. The upper large petal of a
papillionaceous flower.

BA'OBAL. A stone which has obtained
its name from its resemblance to
the fruit of the baobal tree.

BARB.

1. That which grows in place of a
beard.

2. A sort of pubescence in plants.
BA'RBATE. | (from barlatus, Latin.)
BA'RBATED. J Bearded ; awned.
BA'RBED. Bearded ; awiied.
B'ARDIGLIONE. A name given by the

Count de Bournon to Anhydrite.
See Anhydrite.

BA'RIUM. The metallic basis of
baryta, discovered by Sir II. Davy.

BARK. In botany, the covering of
plants, composed of woody hbres,
situated above the wood and under
the cellular integument, consisting
of from one to many layers, accord-
ing to the age of the plant or
branch, an additional layer being
produced every year.

BAR

L 4V]

B A K

BA'RNACLE. (The Lepas balanus of
LinnEeus. Barnacle, Fr. larnacla,
It.) A species of shell-fish, a
pedunculated cirrhipede, frequently
found adhering to the bottoms of
ships in such prodigious numbers,
and of so great a length, as to
materially impede their progress
through the water. Some very
fine specimens may be seen
in the British Museum The
barnacle is known by the names
Anatifer, and Pentelasmis In the
arrangement of Cuvier the barnacle
is placed in the sixth class, namely,
Cirrhopo^a, of Mollusca. Linnaaus
comprised them all in one genus,
Lepas, which Brugieres divided
into two. The name anatifer,
from the two Latin words anas and
fero, signifying duck-bearing, was
given to the barnacle from a ridicu-
lous notion, formerly entertained,
that they enclosed in an embryo
state the young of the barnacle
duck. Sowerby states that fossil
specimens of this marine genus are
found in the calcaire-grossier, of
Paris, and in other similar beds.
Parkinson observes that anatifa
laevis and anatifa striata are both
said by Bosc to be found fossil;
the latter is also said by Gmelin to
be sometimes found fossil, but that
he believes neither of these state-
ments to be supported by sufficient
authority. He, however, gives a
representation of what he believes
to be a fossil barnacle in a flint
stone which he found in the gravel
pits near Hackney-road, and the
opinion he first formed, not only of
its having derived its figure from
animal organization, but of its
affinity to the barnacle, received
corroboration from different speci-
mens which he subsequently met
with. Large bunches of barnacles
attached to pieces of wood are
frequently thrown up by the waves
upon our coasts.

BA'KOLITE. (from fiapvs, heavy, and
\i'0o<f, a stone, Gr.) Carbonate of

barytes. The Baryte carbonatee
of Haiiy. Barolite is found native,
or it may be artificially prepared.
It was first discovered native by
Dr. "Withering, from whom it was
named Witherite. According to
the analysis of Dr. Withering,
carbonate of barytes consists of
barytes 80, and carbonic acid 20.
It is soluble in dilute nitric acid.
It is poisonous. It occurs abun-
dantly in lead veins, that traverse
a secondary limestone in Cumber-
land and Durham, and at Angles-
ark, in Lancashire.

Barolite or "Witherite occurs in
various forms; it is found in irregu-
lar stalactitical minute crystals,
opaque and white; in dodecahedral
crystals formed of two hexahedral
pyramids, of a pale wine-yellow
colour ; and in elongated hexahe-
dral pyramids or spiculas of a chalk
white colour. It is also met with
incrusting fragments of galena,
blende, and limestone ; sometimes
forming crystallized balls of a dirty
white colour, with a striated frac-
ture ; radiating from a centre. In
irregular six sided prisms without
pyramids, and perfectly transpa-
rent, occurring occasionally in the
centre of the balls above mentioned.

BAROSE'LENITE. (from papvs, heavy,
and selenite.) Heavy spar; native
sulphate of barytes, or boroselenite.
The Baryte sulphatee of Haiiy.
A mineral, found abundantly in
this and other countries. It occurs
both massive and crystallised. The
varieties of its crystals are very
numerous. It is of various colours,
white, grey, yellow, brown, red,
green, blue, and black. It consists
of 66 per cent, of barytes and 34
per cent, of sulphuric acid. Its
texture is generally foliated. "When
heated it decrepitates. It is solu-
ble in dilute sulphuric acid. It is
found in veins, in primary, transi-
tion, and secondary rocks.

BA'ROTE. A name given to barytes
by Morveau. See Barytes.

BAR

[48]

B A S

BABE LIMESTONE. An argillaceous,
concretionary limestone, nodular
and interstratified with beds of
shale. A rock of the Upper Silu-
rian series.

BAEYSTKO'NTIANITE. (from fiapvs,
heavy, and strontian.) This min-
eral has also obtained the name of
Strom nite, from its being found at
Stromness, in the island of Pomona.
Its principal constituent is carbon-
ate of strontia, of which it contains
nearly 70 per cent., combined with
sulphate of baryta and a small pro-
portion of carbonate of lime and
oxide of iron. It occurs massive,
of a greyish colour externally, and
of a yellowish white internally.
BAEY'TA. \ from fiapvs, heavy, Gr.)
BA'EYTE. Barytes has been also

BARY'TES. ) called ponderous spar,
heavy spar, and barote. The first
account of the properties, &c. of
barytes, was published by Scheele
in his dissertation on Manganese.
It has obtained its name from its
great specific gravity, which is
about 4, being the heaviest of all
the known earths. It was called
barote by Morveau, and barytes by
Kirwan. Barytes converts vege-
table blues to green. When ex-
posed to the atmosphere it attracts
moisture, and when water is poured
upon it the same appearances pre-
sent themselves as in the slaking
of lime, with the evolution of great
heat, the process being more rapid,
and the eyolution of heat greater.
Barytes is found in two natural
combinations only, with the sul-
phuric and carbonic acids, forming
sulphate and carbonate of barytes.
The primitive crystal of sulphate
of barytes is, according to Haiiy, a
right prism with rhombic bases;
the measurements by the reflecting
gonionometer, according to Prof.
Phillips, are 10T42' on the one
angle,and 78°ir on the other. It
is a violent poison. Nearly all the
compounds of barytes are poisonous,

the best antidotes being dilute sul-
phuric acid, or sulphate of soda in
solution.

BAEY'TIC. Containing barytes; re-
sembling barytes ; having the pro-
perties of barytes.

BA'SALT. (Said to be derived from
an Ethiopian word, basal, signify-
ing iron.) A variety of trap-rock
of a dark green iron grey or brown-
ish black colour, composed of
augite and felspar with some iron
and olivine, the predominant min-
eral being felspar. Sir H. de la
Beche says that basalt is supposed
to be essentially composed of
augite, and titaniferous iron. Ber-
thier says " mais c'est surtout dans
les roches volcaniques que le titane
abonde ; il y est toujours combine
avec le fer et le manganese."

The following are some of the
usual characters of the basaltic
rocks of this country; considerable
tenacity and hardness, a sharp, and
sometimes conchoidal fracture; a
granular aspect, often reflecting
light from a number of brilliant
spots or striae, some of which seem
to be felspar, others hornblende or
augite ; very subject to superficial
decomposition, in which case the
colour passes to a rusty brown,
often mingled with spots of green,
arising apparently from grains of
hornblende. Basaltic rocks are
fusible at a low degree of heat, and
attract the needle strongly. Sp.
gr. of the basalt of Staffordshire is
2.86.

Basalt occurs, sometimes, in
veins or dykes, which traverse
rocks of all ages, filling up fissures
or crevices, and at others, in layers
spread over the surface of the
strata, or interposed between them.
Many modern lavas differ so little
from basalt, that it is unnecessary
to adduce proof of the volcanic
nature of this rock. It often
occurs in the form of regular pillars,
or columns, clustered together ; or,

B A S

[49]

B A S

In scientific language, has a co-
lumnar structure, a character also
observable in some recent lavas.
The columnar arrangement may be
more or less observed in all the
trappean rocks. Basaltic columns
are often curved, they are also
frequently articulated. This struc-
ture is found, by some highly in-
teresting and philosophical experi-
ments, to have originated from the
manner in which refrigeration took
place. Mr. Gregory "Watt melted
seven hundred weight of basalt,
and kept it in the furnace several
days after the fire was reduced.
H; fused into a dark-coloured vi-
treous mass, with less heat than
was required to melt pig-iron ; as
refrigeration proceeded, the mass
changed into a stony substance,
and globules appeared ; these en-
larged till they pressed laterally
against each other, and became
converted into polygonal prisms.
The articulated structure and regu-
lar forms of basaltic columns have,
therefore, resulted from the crys-
talline arrangements of the parti-
cles in cooling ; and the concavi-
ties, or sockets, have been formed
by one set of prisms pressing upon
others, and occasioning the upper
spheres to sink into those beneath.
— Mantell.

On . examination with a lens,
even the more compact varieties of
basalt are seen to be composed of
minute crystalline grains. Easalt,
in enormous masses, often covers
the primary mountain in the Andes,
and arranged in regular columns,
which to the eye of the traveller
appear like immense castles lifted
into the sky. • Basaltic dykes
intersect both primary and second-
ary rocks. Few countries in the
world present more magnificent
basaltic columnar ranges than the
north part of Ireland, and some of
the Hebrides. The Giant's Cause-
way constitutes a small part of a

vast basaltic range, along the north
coast of Ireland, in the county of
Antrim. The promontories of
Fairhead and Borgue, in the same
range, are situated eight miles from
each other : these capes consist of
various ranges of pillars and hori-
zontal strata, which rise from the
sea to the height of five hundred
feet. — Bakewell.

The ancient inhabitants of Brit-
ain formed the heads of their battle
axes, which the people called celts,
from this stone. These celts re-
semble in shape the tomahawks
brought from the South Sea Islands.
Mr. Powlett Scrope has distin-
guished basalt under the following
arrangement; 1. Common basalt,
composed of felspar, augite, and
iron. 2. Leucitic basalt, when
leucite replaces the felspar. 3.
Olivine basalt, when olivine re-
places the felspar. 4. Hauyine
basalt, when hauyine replaces the
felspar. 5. Ferruginous basalt,
when iron is a predominant ingre-
dient. 6. Augite basalt, when
augite composes nearly the whole
rock. »

BASA'LTIC. Composed of basalt ; re-
sembling basalt ; containing basalt.

BASA'LTIFOBM. Kesembling basalt in
its columnar form, or structure.

BASA'LTIC HOENBLENDE. } Two names

BASA'LTINE. j given to

the same mineral. A variety of
common hornblende to which these
names have been given from its
having been found commonly in
basaltic rocks. The primitive
form of its crystals is a rhomboidal
prism. It has by analysis been
found to consist of silica 58,
alumina 27, iron 9, lime 4, and
magnesia 1. Its colour i§ black,
dark-green, or yellowish- green.
Texture foliated.

BA'SANITE. (fidffavos, Gr. lapis quo
prolatur aurum, la/pis Lydiw.)
Lydian stone, a variety of schistose
hornstone. This stone acquired

B A S

[ 50 ] BAT

its name from its having been for-
merly used as a touchstone in
trying the purity of metals : it also
was called Lydian stone, from its
being found abundantly in Lydia.
According to an analysis of it, its
constituents are, silica 75 per cent. ,
lime, magnesia, carbon, and iron.
See Lydian Stoue.

BASILOSATT'BTJS. The name of an
enormous fossil reptile, described
by Dr. Harlan of Philadelphia.
Neither the relation of the basilo-
saurus to other species, nor its geo-
logical position, has been accurate-
ly determined. — Mantell.

BASE, (from basis, Lat. /3a<rt?, Gr.
lase, Pr. lasa, It.)

1. The bottom, or lowest part, of
any thing.

2. In conchology, that part of the
shell in univalves by which they
are attached to rocks, or other sub-
stances ; in multivalves, the oppo-
site extremity to the apex.

3. The substance to which an acid
is united; as in oxide of copper, the
copper is the base.

BA'SIN. (bassin, Fr. latino, It.) In
geology, large concavities filled
with deposits, as the London basin,
the Paris basin, &c. are called
basins. The surface of the earth
is covered with a series of irregular
depressions or basins, divided from
one another, and sometimes wholly
surrounded by projecting portions
of subjacent strata, or by unstrati-
fied crystalline rocks, which have
been raised into hills and moun-
tains of various degrees of height,
direction, and continuity. This
disposition in the form of basins,
which is common to all formations,
has been more particularly ob-
serve^, in the carboniferous series,
from the beds of coal contained
therein having been wrought
throughout their whole extent. In
consequence of this basin-shaped
disposition of the carboniferous
strata a most beneficial result

obtains, namely, that these strata,
which an uninterrupted inclination
in one direction only would soon
have plunged into depths inacces-
sible to man's greatest efforts, are,
by their being placed around the
circumference of the basin, all
brought sufficiently near the sur-
face to be attainable, and are thus
made subservient to his benefit and
comfort.

BA'SSET. A term, used by miners, to
express an upward slanting direc-
tion of a vein, from below to the
surface.

2. The mergence of strata in suc-
cession from each other.

The angle of inclination between
these planes and that of the horizon,
is called their dip or pitch.

BA'SSETTING. Slanting upwards.

BATH- STONE. A species of limestone,
called also Bath- oolite. This mem-
ber of the oolite formation has
been called the great oolite ; it is
of considerable thickness, and
yields an abundant supply of free-
stone for building. It has obtain-
ed the name of oolite from its
being composed of small rounded
grains, or particles, supposed to
resemble the roe of a fish. Bath-
stone consists of minute globules,
cemented together by yellowish
earthy calcareous matter, and a con-
siderable portion of broken shells.
Each of the little grains, rarely
exceeding the size of a pin's head,
would, if broken open, be found to
be composed of concentric coats or
shells, sometimes hollow in the
centre, sometimes enveloping a
small grain. When these grains
are larger, and of the size of peas,
the rock is called Pisolite, or Pea-
stone. When first quarried, Bath-
stone is soft, but it soon becomes
hard by exposure to the atmosphere.

BATH- OOLITE. See Bath-stone.

BATEA'CHIA. (from fiaT-pa^o?, a frog,
Gr.) The second order of the

BED

[51 ]

BEL

class Amphibia, comprising the
frog, toad, &c.

BA'TRACHITE. (from /3aT/>axe«os, Gr.
batrachites, Lat.) A fossil of the
colour of a frog ; a fossil frog ; a
fossil resembling a frog, either in
form or colour.

Under the name of batrachite or
bufonite, are found figured, in the
works of some ory otologists, a great
number of fossil bodies, more or
less rounded and shining, which
are evidently portions of the teeth,
or deretary palates, of fishes. The
above names were given because it
was imagined that they had been
engendered in the heads of toads or
frogs. See Bufonite.

BEAK.

1. In conchology, the continuation
of the body of univalves in which
the canal is situate.

2. In ornithology, the bill, or horny
mouth of a bird.

3. In botany, applied to an elonga-
tion of the seed-vessel; proceeding
also from the permanent style; also
to naked seeds.

B'EAR. The name given for a block
of sandstone, which, having been
exposed to an intense heat in the
furnace, has become converted into
a substance resembling quartz rock.

BEABD. (from larla, Lat. barle, Pr.
larla, It.)

1. In botany, a bristle-shaped pro-
jection, growing out from the
glume or chaff, in corn and grasses;
called also the awn.

2. In conchology, the process by
which some univalves adhere to
rocks, &c.

BED. A stratum of considerable
thickness. It is desirable that the
geological student should draw a
distinct line between the words
bed and stratum. Whenever a
layer, or stratum, is of the thick-
ness of two yards or more, it should
be denominated a bed, but other-
wise a stratum. There are some-
times found many distinct strata in

the thickness of an inch; to de-
nominate these as beds would be
absurd. Let it therefore be kept
in mind that the words bed and
stratum are not synonymous. By
a led there should be understood a
series of layers, or a succession of
deposits of earthy matter so con-
tinuously formed that the whole
adhere more or less firmly together.

BE'ETLE. A coleopterous insect, the
scarabaeus of Linnaeus. Eemains
of beetles have been found in the
oolite : wing covers of beetles occur
in the shale of the Danby coal-pits,
in the eastern moorlands of York-
shire.

BE'ETLE. To jut out; to hang over:
thus rocks are said to beetle.

BE'ETLE-STONE. A name given to
coprolites, from their falsely im-
agined insect origin.

BEHE'MOTH. A huge animal spoken
of in the Scripture, supposed by
some to mean the elephant, by
others the ox, and by Bochart the
hippopotamus.

BE'LEMNITE. (from /Se'Xe/^oi/, Gr. a
dart.) Belemnite, thunderstone,
or arrow-head. An extinct genus
of chambered molluscous aminals,
having a straight tapering shell.
Belemnites are found in the second-
ary formation only, the lowest
stratum containing their remains
being the muschel-kalk, and the
highest the upper chalk of Maest-
richt. M. Be Blainville has given
a list of ninety-one authors, from
Theophrastus downwards, who have
written on the subject of belern-
nites. The most intelligent of
these agree in supposing these
bodies to have been formed by
cephalopods allied to the modern
sepia. That fossil which is called
a belemnite was a compound in-
ternal shell, made up of three
essential parts, which are rarely
found together in perfect preserva-
tion. The belemnite is one of the
most common fossils of the chalk,*

BEL

[52]

B E

it resembles an elongated conical
stone, of a crystalline, radiated
structure, and is generally of a
brown colour : some limestones on
the Continent of Europe are almost
wholly composed of them. Ink-
bags, resembling those of the Loligo,
have been found in connection with
belemnites in the lias at Lyme
Regis; these, in some instances,
are nearly a foot long, and prove
that the animal to which they
belonged must have been of great
size. The fact of these animals
having been provided with a reser-
voir of ink, affords an a priori
probability that they had no ex-
ternal shell, but recent discoveries
decide the question, two specimens
having been found each containing
an ink-bag within the anterior
portion of the sheath ; and, con-
sequently, all the species of belem-
nites may henceforth with certainty
be referred to a family in the class
of Cephalopods. Eighty-eight
species of belemnites have already
been discovered; and the vast
numerical amount to which indivi-
duals of these species were extended,
is proved by the myriads of their
fossil remains that fill the oolitic
and cretaceous formations. — Buck-
land, £aJcewell, Mantell.

BELE'HNO-SE'PIA. The name proposed
to be given by Professor Buckland,
in concurrence with M. Agassiz, to
a new family of cephalopods, to
which family may be referred
every species of belemnites.

BELLE'ROPHON. An extinct genus of
mollusca, belonging to the order
Heteropoda, found in the Silurian
and Carboniferous rocks, the shell
of which was without chambers.
De Montfort placed the bellerophon
among chambered shells; De Blain-
ville assigned their position next to
Bulla.

BELO'PTERA. A genus of fossil fishes
established by Deshayes, of which
no recent species is known ; Cuvier

considered that the remains thus
placed in a distinct genus were
merely portions of some sepia.

Bi' VALVE, (bivalvis, Lat. bivalve, Er.)
An animal having two valves,
shells, or shutters, as the oyster,
muscle, &c.

BE'MBRIDGE BEDS. These are of the
Eocene period, and consist of the
upper marls, the lower marls, the
oyster-bed, and the limestone bed.

BE'RENICTA. The name given by La-
mouroux to a genus of fossil corals.
One species, B. irregularis, is found
in the Wenlock limestone, at Dud-
ley. It is thus described — "opening
of the cells round, distant where
the surface is flat, generally rear
together where it is uneven ; more
or less regularly disposed from a
centre. — Murchison. Silurian Sys-
tem.

BEBG'MANNITE. A mineral so called
in honour of the celebrated chemist
Bergmann. It occurs massive and
is of a greenish or greyish white :
it has been found in Norway.

BE'RYL. (leryllus, Lat. leryl, Er.)
A crystallised compound of the
earth glucina with silica, alumina,
lime, and oxide of iron. The beryl
is a gem, or precious stone, of the
genus emerald, but less valuable
than the emerald. It differs from
the precious emerald in not possess-
ing any of the oxide of chrome,
from the presence of which the
emerald obtains its splendid green
colour. The aqua-marine is a
variety of the beryl, having a more
transparent texture. The beryl is
of a greyish-green colour, blue,
yellow, and sometimes nearly
white; occasionally different colours
appear in the same stone. Beryl is
found in many parts of the world,
but the finest specimens are
brought from Siberia. Vauquelin
first discovered the earth glucina
from analyzing the beryl. Some
mineralogists consider beryl and
emerald to differ merely in their

B I L

[53]

BIN

colours, presenting, as they state,
an uninterrupted series; others,
however, constituting emerald a
species, divide it into two sub-
species, namely, precious emerald
and beryl. Specific gravity from
2-65 to 2-75. Hardness = 7'5 to
8.

BE'RYX LEWESIE'NSIS. A fossil dis-
covered in the Lewes chalk
quarries, of the length of twelve
inches, greatly resembling the
dory, and by the workmen called
the Johnny Dory. This is the
most abundant of the Sussex ich-
thyolites ; its scales are very
frequent in all the pits of the
South Downs, as well as in those
of Surrey and Kent. — Mantell.
Cuvier places the beryx in the
family Percoides, order Acanthop-
tergii.

BE'EYX EA'DIANS. A fossil fish from
the chalk-marl, of the length of
seven inches. This, like the
Beryx Lewesiensis, last described,
belongs to the family Percoides,
order Acanthoptergii.

BICA'PSULAR. Having two capsules,
or seed vessels.

BICI/PITAL. | (from biceps, Lat.)

BICI'PETOUS. ) Having two heads.
It is a term applied to muscles,
which have two distinct origins*.

BICO'RNUS. (bicornis, Lat.) Having
two horns.

BICU'SPID. (from 'bis and cuspis, a
spear, Lat.) Two pointed; two-
fanged.

BI'FID | (from bifidus, Lat. ) Cleft,

BI'FIDATED j or cloven, into two ;
opening with a cleft ; two-cleft,
but not very deeply divided.

BIGE'MINATE. In botany, applied to
a compound leaf, having a forked
petiole, with several petioles, or
leaflets, at the end of each divsion.

BILA'BIATE. (from bis and Idbium, a
lip, Lat.) Two-lipped ; furnished
both with an outer and inner lip.

BI'LDSTEIN. (from bild, shape, and
stein, stone, German.) A massive

mineral, with sometimes an imper-
fect slaty structure. It is also
called agalmatolite. By M. Brong-
niart it has been named steatite
pagodite, but it is wanting in
magnesia, which is present in all
steatites.

BILO'BED. } (from bis and lobus, Lat.)

BILO'BATE. ) Divided into two
lobes.

BILO'CULAR. (from bis and loculus,
Lat.) Two-celled; divided into
two cells.

BIMA'RGINATE. In conchology, fur-
nished with a double margin as far
as the lip.

BIMA'KA. (from bis and manus,
Lat.) The first order of the class
mammalia ; this order consists of
but one species, viz., man. Some
naturalists, amongst whom are
Ray, Brisson, Pennant, Swainson,
Daubenton, &c., &c., would ex-
clude man from the pale of the
animal kingdom ; others have
regarded him as an example of an
order per se. From one of the
structural peculiarities of the race,
the possessing two hands, Cuvier
has applied to the order the term
Bimana, which is now very com-
monly adopted.

BI'NARY. (binareus, Lat.) Arranged
by twos ; containing two units.

BI'NATE. (from binus, Lat.) Two
and two ; by couples ; growing in
pairs; a fingered leaf of two
leaflets, inserted at the same
point, precisely on the summit of
the petiole.

BIND. Called also clunch; a name
given to the soil on which the coal
strata rest. An argillaceous shale,
more or less indurated, sometimes
intermixed with sand resembling
sandstone, but generally decom-
posing into a clayey soil on
exposure to the atmosphere. — Bake-
well.

BINO'XIDE. — When oxygen combines
with another substance in the
proportion of two equivalents of

BIS

[54]

BIT

oxygen to one of the other, the
result is a binoxide, or dentoxide.

BI'OTITE. A mineral, called also
Magnesia Mica, a variety of mica,
containing from 10 to 25 per cent,
of magnesia, and only 12 to 20 of
alumina.

BIPARTITE, (from Us and partitus,
Lat.) Having two correspondent
parts; an epithet for the corolla,
leaf, and other parts of plants,
when divided into two corres-
pondent parts at the hase.

BIPE'NNATE. j (bipennis, Lat. Having

BIPE'NNATED. ) two wings.

BIPE'TALOTTS. (from Us, Lat. and
TreVaXoi/, Gr.) Consisting of two
flower leaves ; having two petals.

BIPI'NNATE. (lipinnatum, Lat.) Doub-
ly pinnate ; applied to a compound
leaf, having a common petiole,
which produces two partial ones,
upon which the leaflets are inserted.

BIPINNA'TIFID. Having pinnatifid
leaves on each side the petiole.

BIRA'DIATE. j (from Us and radiatus,

BIRA'DIATED. ) Lat.) Consisting of
two rays.

BIBHOMBOI'DAL. Having a surface of
twelve rhombic faces.

BIRO'STRATE. (from binus and rostrum,
Lat.) Having a two-beaked prom-
inence ; two beaked.

BIROSTRI'TES. A fossil bicornuted
bivalve with conical umbones.

BI'SMTJTH. (lismut, German, bismuth
and bismut, Fr.) A metal of a
reddish- white, or cream colour. It
is neither malleable nor ductile, its
specific gravity is 9-8, it fuses at a
temperature of 476 Fahrenheit.
In hardness it is intermediate
between gold and silver. Bismuth
unites with most metals, rendering
them generally more fusible, and
in some cases remarkably so. Eight
parts of bismuth, five of lead, and
three of tin, constitute what has
been called Sir I. Newton's fusible
metal, which liquefies at the temp-
erature of boiling water, 212°, and
may be fused over the flame of a

candle in a piece of stiff paper.
Bismuth was discovered in the
early part of the sixteenth century,
and is mentioned by Bermannus.
It occurs in veins in primitive
rocks, as gneiss, granite, mica-slate,
and clay-slate, in Saxony, Bohemia,
France, Sweden, and Cornwall.
One part of bismuth with five of
lead and three of tin form the soft
solder used by pewterers ; it is also
used in the manufacture of printer's
types. It is with a compound
of two parts of bismuth, one
of lead, one of tin, and four of
mercury, the whole being fusible
at a temperature under that of
boiling water, that glass globes are
silvered on the inside ; a piece of
this compound being placed within
the globe, the latter is plunged
into hot water, the metallic com-
pound readily melts, and the globe
being turned round, the fluid metal
is spread over the internal surface.
BISTJ'LCATE. | (lisulcus, Lat.) Cloven
BISUI/COUS. ) footed, as the ox, or

the pig.

BITTER SPAR. See Lolomite.
BITTJ'ME, i (bitumen, Lat. litume, It
BI'TUHEN, ) Utume, Fr, matiere
liquide, epaisse, noire et inflammable,
qui se trouve dans le seine de la terre,
et dont on pretend qrfon se servoit
autrefois au lieu de ciment.) The
term bitumen is applied to a num-
ber of inflammable substances
found in the earth, or issuing from
the earth's surface, and these are
knownundertheirnamesof naphtha,
petroleum, mineral tar, mineral
pitch or maltha, asphalt, elastic
bitumen, jet, mineral coal, amber,
and mineral tallow. These, how-
ever, may perhaps be more correctly
called bituminous varieties Bitu-
men is a substance of a peculiar
kind, seeming to partake both of
an oily and resinous nature, and is
found either buried in, or proceed-
ing from, different parts of the
earth, in different states of consis-

BIT

[55]

B L A

tence. Bitumen is composed of
carbon and hydrogen. It appears
that formerly bitumen was general-
ly used instead of mortar, and
authors suppose that the tower of
Babel, the walls of Babylon, of
Sodom, and other places, were
built of bricks cemented together
by bitumen, and that the ark of
Noah, and the vessel of bull-rushes
in which Moses was exposed, were
coated with this substance. Bitu-
men, when fluid, has been called
by some Latin writers, oleum vi-
vum. Lyell says that the tar-like
substance, which is often seen to
ooze out of the Newcastle coal
when on fire, and which makes it
cake, is a good example of bitumen.
Mr. Hatchett says "we may, with
the greatest probability, conclude
that bitumen is a modification of
the resinous and oily parts of vege-
tables, produced by some process of
nature, which has operated by slow
and gradual means on immense
masses, so that, even if we were
acquainted with the process^ we
should scarcely be able to imitate
the effects, from the want of time,
and deficiency in the bulk of the
materials. But although bitumen
cannot at present be artificially
formed from the resinous and other
vegetable substances by any of the
known chemical processes, yet there
is every reason to believe that the
agent employed by nature in the
formation of coal and bitumen has
been either muriatic or sulphuric
acid." The varieties of bitumen
will be separately described under
their different names.— Parkinson.
Lyell. Bakewell.

BITU'MINATED. (bitummatus^ Lat.)
Prepared with bitumen; impreg-
nated with bitumen.
BITTTMINI'FEROUS. Yielding bitumen ;

containing bitumen.
BITT/MINISE. To prepare with, or
coat with, bitumen. 2. To convert
into bitumen.

BITUMINISA'TION. The preparing, or
impregnating, with bitumen.

BITTJMINIOTTS SHALE. (The Brands-
chiefer of Werner : le schiste
bitumnieux of Brochant : schiste
argileuxbitumineux of Brongniart.)
An argillaceous shale, much im-
pregnated with bitumen, very com-
mon in the coal measures. A
blackish-brown, or greyish, sub-
variety of shale; fracture slaty;
usually soft and unctuous to the
touch. Specific gravity about
2. When placed in the fire, it
blazes, crackles, and gives out a
black smoke and bituminous odour,
and is converted into a whitish or
reddish ash: it sometimes effer-
vesces slowly with acids.
BITUMINOUS SPRINGS. We are in-
formed by Sir C. Lyell that springs
impregnated with petroleum, and
the various minerals allied to it,
are very numerous, and are, in
many cases, undoubtedly connected
with subterranean fires. The most
powerful yet known, are those on
the Irawadi, in the Burman empire,
which, from one locality, are said
to yield 400,000 hogsheads of pe-
troleum annually.

BLACK CHALK, (the Zeichen scheifer
of Werner ; argile schisteuse gra-
phique of Haiiy ; ampelite gra-
phite of Brogniart; le schiste a
dessiner of Brochant.) A clay of
a bluish black colour, extremely
soft, a quality which it owes to the
presence of about twelve per
cent, of carbon. That most
esteemed is found in Italy and
Germany, and takes its name
from those countries respectively.
It is massive, opaque, soils lightly,
and writes ; retains its colour in
the streak, and becomes glistening ;
is soft, sectile, does not adhere to
the tongue, feels fine, but meagre,
and is infusible. According to
Wiegleb, a variety from Bayreuth
contained silica 64 '50, alumina

B L A

[ 56]

BOG

11-35, oxide of iron, 2'75, carbon
11, water 7.5.

BLACK-JACK. A name given by miners
to a sulphuret of zinc. See Blende.

BLACK-LEAD. The substance about to
be described has been thus named
from its leaden appearance, or
general resemblance to lead, but
it does not in fact contain a single
particle of lead in its composition.
It is the same as plumbago and
graphite. Black-lead is a com-
pound of carbon, with a small
portion of iron, and some earthy
matters. It is of a dark steel-grey
colour, inclining to iron-black ; it
occurs regularly crystallised; in
granular concretions ; massive and
disseminated ; it has a greasy feel,
and blackens the fingers, or any
other substance to which it is
applied ; it is infusible ; and burns
with much difficulty. According
to Yauquelin its constituent parts
are carbon 92., iron 8. ; but
according to Allen and others, it
contains only five parts per centum
of iron. Its nature was first in-
vestigated by Scheele, who, by
combustion, converted nearly the
whole into carbonic acid gas, the
residuum being oxide of iron.
Black-lead, or carburet of iron, is
used for many domestic purposes,
but its principal use is in its manu-
facture into black-lead pencils. It
is found in the primary, transition,
and secondary rocks. Anthracite
resembles and appears to pass into
plumbago, or black-lead ; common
coal, also, according to Bakewell,
sometimes graduates into plumbago.

BLACK- WADD. An ore of manganese,
used as a drying ingredient in
paints.

BLASTOIDE'A. An extinct order of
the class Echinodermata. The
genera, which are all extinct, are
Pentremites, Eleacrinus, Codonas-
ter, Zygocrinus, and Phyllocrinus.

BLA'TTA. (llatta, Lat.) The cock-
roach, placed by Linnseus in the

second order, Hemiptera, of the
seventh class, Insecta.

BLENDE. (from llenden, Germ, to
dazzle, or blind.) Sulphuret of
zinc ; a metallic ore whose con-
stituent parts are zinc, iron, sul-
phur, and a trace of quartz. Blende
is called by the English miners
black-jack; it occurs in the lead
mines. The primitive form of its
crystals is a rhomboidal dodecahe-
dron ; there are several varieties
known, as brown blende, yellow
blende, black blende.

BLOOD-STONE. (See Heliotrope.) He-
matites ; a variety of agate to which
the name bloodstone has been
applied from some absurd notion of
its efficacy in restraining hemor-
rhage.

BLUE-JOHN. A name given by the
miners to fluor spar ; called also
Derbyshire spar, in which county it
occurs in great abundance. It is
manufactured into vases and orna-
mental figures, being capable of
being turned by the lathe. Bake-
well, in describing the blue-John,
or fluor spar mine near Castleton,
in Derbyshire, observes, " the
crystallizations and mineral incrus-
tations on the roof and sides of the
natural caverns which are passed
through in this mine, far exceed in
beauty those of any other cavern
in England ; and were the descrip-
tions of the grotto of Antiparos
translated into the simple language
of truth, I am inclined to believe it
would be found inferior in magni-
ficence, and splendour of mineral
decoration, to the natural caverns
of the fluor mine."

BLUE VITKOIL. Sulphate of copper.

BLUFE. Any high head-land, or
bank, presenting a precipitous front.

BOG-IEON-ORE. ( Iron ore peculiar to

BOG-OEE. ( boggy land. Sir

C. Lyell observes, " at the bottom
of peat mosses there is sometimes
found a cake, or pan, of oxide of
iron, and the frequency of bog-iron

BOB,

[ 57]

B 0 11

ore is familiar to the mineralogist.
From what source the iron is derived
is by no means obvious, since we
cannot in all cases suppose that it
has been precipitated from the
waters of mineral springs. It has
been suggested that iron, being
soluble in acids, may be diffused
through the whole mass of vege-
tables, when they decay in a bog,
and may, by its superior gravity,
sink to the bottom, and be there
precipitated, so as to form bog-iron
ore. Dr. Man tell observes, " the
formation of what is termed bog-
iron ore, found in marshes and peat
bogs, is supposed to have been
derived from the decomposition of
rocks over which water has flowed ;
but the observations of Ehrenberg,
seem to indicate a different ori-
gin." Ehrenberg discovered that
bog-iron consists of innumerable
articulated threads, of a yellow-
ochre colour, composed partly of
flint, and partly of oxide of iron ;
these threads being the cases of a
minute animalcule, termed Gaillon-
ella ferruginea.

BOLE, (from PU)\O$. Gr.) A friable
clay, or earth, often highly coloured
with iron. It occurs in solid
amorphous masses of a yellow red,
or blackish-brown colour, or pitch
black; it is found in wacke, and
basalt, from the decomposition of
which it may arise.

BOLE'TTTS. A genus of mushrooms, of
the order Eungi.

BOLO'GNA STONE. ] A variety of sul-

BOLO'GNIAN STONE, j phate of barytes,
possessing phosphoric properties.
These properties were first dis-
covered accidentally by Yicenzo
Casciarolo, an Italian shoemaker.

BOEA'CIC ACID. A compound of
boron and oxygen, containing
about 26 per cent, of boron and 74
of oxygen. It is found native on
the edges of certain hot mineral
springs in Italy. It occurs in
scaly crusts, or small pearly scales,

and massive. Homberg was the
discoverer of boracic acid. Boracic
acid may be obtained by adding to
a solution of borax half its weight
of sulphuric acid. The term Sas-
solin has been applied to boracic
acid, from its presence in the hot
springs of Sasso.

BO'EACITE. Borate of magnesia; a
combination of boracic acid with
magnesian earth. Boracite is found
imbedded in gypsum, in Hanover
and Holstein ; its colours are white
and greyish ; it is generally of a
cubic form, and possesses, when
heated, strong electrical properties.
Borate of magnesia may be arti-
ficially obtained. Before the blow-
pipe boracite froths, emits a green-
ish light, and is converted into a
yellowish enamel.

BO'EATE. A combination of boracic
acid with any saturated base ; a
salt formed by the combination of
any base with the acid of borax. —
Parties.

BO'EAX. (borax, Lat. lor ax, Er. lor ace,
It.) Subborate or borate of soda ;
a salt of soda formed of the alkali
with boracic acid . It is prepared
artificially by purifying the natural
borate of soda, a mineral found in
Thibet, where it is held in solution
in the waters of a lake, which also
contains common salt. Borax in
its impure state is called tincal-
and is purified by calcination, solu-
tion, and crystallization, after its
importation. Borax is an import-
ant article in the arts, as a flux in
the reduction of many metals,
especially in assaying ; it is also
used in medicine. According to
Berzelius, borax consists of soda
16-31, boracic acid 36-59, water
47-1. Bergmann states the pro-
portions to be boracic acid 34, soda
17, water 49; and Kir wan gives
as his analysis, boracic acid 84,
soda 17, water 47.

BOBE. A violent rush of tidal water.

B 0 V

[58]

BO'BON. The undecomposable base of
boracic acid ; this may be obtained
by heating in a copper tube two
parts of potassium with one of
boracic acid previously powdered
and fused. Boron is a dark olive
coloured substance, having neither
taste nor odour, insoluble in water,
and a non-conductor of electricity.
It is about twice the weight of
water. Its symbol is B.

Boss, (bosse, Fr.) A protuberance
or swelling ; a kind of knob or stud.

BOSSED. Knobbed or studded.

BOTHBTOLE'PIS. The name assigned
to a genus of ichthyolites of the
Old Red Sandstone, and described
by Agassiz in his Poissons Fossiles.

BOTHBODE'NDEON. (from fioOpos and
SevSpov, Gr.) An extinct genus of
coniferge belonging to the coal for-
mation. The bothrodendron has a
stem not furrowed, covered with
dots. Scars of cones, obliquely
oval. The stems are marked with
deep oval or circular concavities,
which appear to have been made
up by the bases of large cones.
These cavities are ranged in two
vertical rows, on opposite sides of
the rock, and in some species are
nearly five inches in diameter. —
Prof. BucUand.

BO'TBYOID. | (from fiorpvs, a bunch

BOTBYOI'DAL. ) of grapes, and e/£os,
form.) Resembling a bunch of
grapes ; clustered like grapes.

BOTBY'OLITE. (from fiorpvs, a cluster
of grapes, and \i'0o<?, Gr.) " A
mineral presenting an aggregation
of large sections of numerous small
globes is termed lotryoidal ; but
when the globes are larger, and the
portions are less and separate, the
appearance is expressed by the
termmammillated." Phillips. Grape
stone ; a variety of prismatic dato-
lite, occurring in mammillary con-
cretions.

BO'VEY COAL. A name given to wood-
coal, from its having been found in
abundance at Bovey Heathfield

B 0 V

near Exeter; called also brown-
coal. In wood-coal we may almost
seize nature in the act of making
coal, before the process is completed.
These formations of coal are far
more recent than those of common
coal, and have been referred to the
first, or Eocene, period of the
tertiary formations. Heat and
pressure appear to be required to
convert wood coal into mineral
coal. Bovey-coal contains carbon
77*19, oxygen 19*34, hydrogen
2 '54, earthy parts 1.

" The precise age of the Bovey
coal," says Sir H. de la Beche,
" cannot at present be well deter-
mined. A body of water has
passed over it, working hollows in
the clay, and leaving a large
deposit of transported substances in
some situations. It also appears
to have been tranquilly deposited
in a previously existing depression.
The area comprising the surface of
this deposit is far more extensive
than is usually given, and it has
certainly once occupied a greater
elevation, as a mass, than it now
does, the upper portion having
been removed by denudation. The
principal deposit of lignite occurs
near Bovey Tracy, in Devonshire,
at the north-western end of the
deposit. Beneath about twenty
feet of what the workmen term
the head, there is an alternation of
compressed lignites; shales or clays.
The lignite is composed of dicoty-
ledonous trees, many of which are
knotted. The most useful product
of this deposit is a clay used in the
potteries, in some cases so fine as
to constitute what is termed pipe-
clay. Lignite more or less ac-
companies the clay throughout,
occurring either in beds or in small
detached pieces. Animal remains
must be rare ; for I could not, after
diligent search, obtain any traces
of them, though I was told some
shells had been seen at Teignbridge.

BRA

[59]

BRA

According to. Mr. Whiteway and
Mr. Kingston, the Bovey deposit
consists chiefly of five clay beds,
and as many of gravel, the latter
varying from 100 to 50 feet in
width. The clay beds are described
as undulating, like the waves of
the sea; and it is stated that
beneath the four more western
beds the Bovey-coal is found."

BOT/LDEE. I Large fragments, or roun-

BO'WLDEE. ) ded masses of any rock
found lying on the surface, or,
sometimes, imbedded in soil, and
differing from the rocks where they
are found ; these fragments, or
outlying boulders, are of no deter-
minate size, they are supposed to
have been transported by the force
of water, and are occasionally
found at very great distances from
their parent rocks. The mass of
rock on which is placed the statue
of Peter the Great at St. Peters-
burgh, is a detached block of
granite, or a boulder, forty-two
feet in length, twenty-seven feet
broad, and twenty-one feet high,
and was removed from the Gulf of
Finland.

The Hon. Fox Strangways says
" the celebrated block out of which
the pedestal which supports the
statue of Peter the Great is cut was
a rolled boulder of the red Finland
granite. It was not brought, as
has been asserted, from Siberia,
nor, by human means at least,
from Finland : but was found,
among many others of smaller size,
in a bog between Petersburg and
Cesterbeck. It was diminished
two thirds, before placing the
statue on it."

BEACHELY'TBA. A family of coleop-
terous insects, having but one
palpus to the maxillaB. It com-
prises only one genus, namely
Staphylinus.

BEA'CTEA. (bractea, Lat.) In botany,
a leafy appendage to the flower or
stalk, differing from the other

leaves of the plant in form or
colour ; the floral leaf. Bracteas
vary greatly in appearance ; most
commonly they are green and her-
baceous. The leaf, in the axilla of
which a flower-bud is produced, is
called a bractea. The most re-
markable sort of bractea is that
called spathe ; the spathe or bractea
of many flowers is membranous.
"When two or more bracteae, instead
of appearing singly on the principal
flower- stalk, are opposite, or ver-
ticillate, they form an involucrum.

BEA'CHIAL. (from brachium, an arm,
Lat. Irachial, Fr. del braccio, It.)
Belonging to the arm.

BEA'CHIATE. (brachiatm, Lat.) Four-
ranked; applied to stems, when
they divide and spread in four
directions, crossing each other.

BEANCHI'FEEA. In the conchological
system of De Blainville, we find
branchifera placed in the order
Cervicobranchiata, and it comprises
three genera, namely, Fissurella,
Emarginula, and Parmophorus.

BBACHTIO'PODA. (from ftpa^ltav, an
arm, and?™*)?, a foot, Gr.) Animals
having arms instead of feet. The
brachiopoda are all bivalves. Bra-
chiopoda forms the first order of
the class Molluscoidea.

BEACHIO'PODOUS. Having arms in
the place of feet and legs; be-
longing to the class Brachiopoda.

BEACKLESHAM BEDS. These beds
constitute a portion of the Bagshot
series, lying between the Lower
Bagshot and the Barton Clay.
They take their name from Brackle-
sham in Sussex, but are best seen
in the Isle of Wight : their thick-
ness in some places is about 110
feet.

BEADFOBD CLAY. A blue unctuous
clay, occurring at Bradford, a
member of the Cornbrash group;
it is full of Apiocrinites Parkinsoni.

BBADY'PODA. Slow-moving animals,
with their bodies generally covered
by a hard crust. Some want the

BRA

[ 60]

B R I

incisor teeth; others want the
incisors and cuspidati; in others,
the jaws are destitute of teeth.
Placed by Linnaeus in the class
Mammalia, and composing the
third order. The order Bradypoda
includes the genera Bradypus, or
Sloth, Mermecophaga, Ant-eaters,
Manis, Scaly Lizard or Pangolin,
Dasypus, Armadillo, and Ornithor-
rhynchus. Duck-billed animal.

BRA'DYPUS. (ppaSinrovs, Gr.) The
sloth, a genus of the order Brady-
poda, class Mammalia. These
animals have no fore-teeth ; they
have six grinders in either jaw;
and their bodies are covered with
hair. There are several species.

BRA'NCHIA. (from ppdy%ia, Gr.)
This word is rarely used substan-
tively ; it makes branchiae in the
plural. Branchiae are filamentous
organs for breathing in water ;
gills. Respiration is effected by
the transmission of water through
the mouth, over the surface of the
fringe-like branchiae; and the
blood is transmitted to the gills
from the ventricle, whence, instead
of returning immediately to the
heart, it is conveyed by the bran-
chial veins to the body ; these
veins after giving branches to the
anterior parts, unite to form the
aorta, which sends the arterialized
blood through the rest of the
system, without the aid of a sys-
temic heart.

BRANCHIO'PODA. (from ppd^xta> an<^
TTOVS, Gr.) The third order of the
class Crustacea.

BBANCHTO'PODOTJS. Gill-footed ; be-
longing to the order Branchiopoda.

BBANCHIO'STEGI. (from ppd^^ia, gills,
and ffre'ryos, or <rre'ryi/, a covering.)
A term used to express one of the
orders of fishes, the characters of
which are, that the rays of the
fins are of a bony substance.

BBANCHIO'STEGOTTS. Having the cha-
racters of the branchiostegi ; be-
longing to the order Branchiostegi ;
having the gills covered.

BRA'NCHIPTJS. The cancer stagnalis
of Linnaeus ; an animal belonging
to the crustaceans, having the legs
reduced to soft paddles, and com-
bining the functions of respiration
with those of locomotion. In the
branchipus, we find antennae, but
no crustaceous legs. The soft
branchiae of branchipus perform
the double office of lungs and feet.

BRAU'NITE. (The Brachytypes man-
ganerz of Mohs.) A mineral of a
brownish black colour, occurring
massive and crystallized, consisting
of protoxide of manganese 87 per
cent. ; oxygen 10 per cent. ; baryta
2.26 per cent. ; and water nearly
1 . It has been thus named after
Mr. Braun of Gotha.

BRE'CCIA. (Ital.) Any rock com-
posed of angular fragments ce-
mented together.

BRE'CCTATED. Composed of angular
fragments united into a mass by
.cement.

BRE'CCTATED AGATE. A beautiful
variety of agate, consisting of frag-
ments of ribbon agate united by a
base of amethyst, it is found in

BEEI'SLAZITE. A Yesuvian mineral,
thus named after Breislak.

BBE'WSTEETTE. An earthy mineral,
so named after Sir D. Brewster.
It occurs in small white, or yel-
lowish coloured crystals, and con-
sists of silica 53 -65, alumina 17'4,
strontia 8'32, baryta 6'75, lime
1-34, water 12-58, oxide of iron
0-29. Sp.gr. 2'1, hardness 5 to 5-5.

BEI'LLIANT. (Irillant, Fr. Irillante,
It.) A diamond cut into angles,
by which the rays of light are
refracted, and a greater brilliancy
is obtained.

] Rock-crystal,
, j or crystallized

BBI'STOL-STONE.

BRISTOL-DIAMOND,

quartz. Very fine specimens are
found in the rocks near Bristol, and
these have thence obtained the
name of Bristol diamonds. They

B E 0

are pure silica, crystallized in six-
sided prisms, terminated by six-
sided pyramids.

BROME. | (from fipw/jios, odour, Gr.)

BRO'HINE. j A simple, or element-
ary substance, being non-metallic.
Bromine exists in sea water, either
as bromine of sodium or bromine
of magnesium ; it was discovered
in 1826 by M. Balard, of Montpel-
lier. At common temperatures it
is liquid, of a dark red colour by
reflected, of a hyacinth- red by
transmitted light. At 116° Fah.
it boils ; between 0 Fah. and — 4
it congeals. The density of its gas
is 5-54 ; its equivalent 126-3 ; its
symbol Br. It acts powerfully on
animal substances, and is extremely
poisonous. It unites with all the
simple bodies, and with the metals,
forming, with the latter, a class of
compounds called bromides. — Phil-
lips. Bromine has obtained its
name from its powerful and un-
pleasant smell ; its odour is suffo-
cating, and its taste pungent.

BRO'NTIA. (from ppovrrj, Gr. thunder,
from its being supposed that these
fossils were thrown to the earth by
thunder.) A fossil echinite of the
family Cidaris.

BRO'NZITE. A mineral called by
Werner Blattriger anthophyllite,
and by Haiiy Diallage metalloide.
It has a yellowish brown colour,
with a semi-metallic lustre. It is
found in serpentine, in Shetland
and in Upper Styria, and in green-
stone in many other places. Ac-
cording to Klaproth, it consists of,
silica 60; magnesia 27'5; oxide
of iron 10*5 ; water 0'5. Hard-
ness = 4 — 5. Specific gravity =
3 — 3-3.

BROWN-COAL. A fresh-water forma-
of the tertiary series, but to which
sub- division of the tertiary period
it may belong is considered un-
certain by Sir C. Lyell, from the
extreme rarity of shells found in it.
Professor Buckland states, " In

[ 61 ] B K 0

some parts of Germany this brown-
coal occurs in strata of more than
thirty feet in thickness, chiefly
composed of trees which have been
drifted, apparently by fresh water,
from their place of growth, and
spread forth in beds, usually
alternating with sand and clay, at
the bottom of then existing lakes
or estuaries." The varieties of
wood found in the brown coal
strata are said to belong entirely to
dicotyledonous trees; but among
the impressions of leaves some have
been referred to a palm, by Prof.
Lindley, and others resemble the
Annamomum dulce, and Podocarpus
macrophylla, all indicating a warm
climate.

" The place in the series of the
supracretaceous rocks," says Sir H.
de la Beche, " to which the brown
coal formation of Germany should
be referred, does not appear to be
as yet well determined. This
deposit is characterized by an
immense quantity of vegetable
remains, and is probably of differ-
ent ages. The brown-coal may be
traced from the environs of Aix-Ia-
Chapelle to the Ehine. It there
occurs in a narrow plateau between
the latter and the Erst, and acquires
a thickness of above 100 feet
between Bonn and Cologne, without
any extraneous bed. The brown-
coal deposit rests on the declivity
of the grauwacke mountains on the
right bank of the Ehine, and is
connected with the trachytic con-
glomerates and basaltic formations
of the Siebengebirge. It extends
to the country around Leipsic, to
the Elbe as far as Eorgan, and
occurs frequently in the low tracts
between Magdeburg and the Hartz.
It is found in the level country
between the Elbe and the Oder.
It generally rests upon a compact
tenacious clay, and is covered by
large masses of sand." — Geological
Manual.

B IT C

[62]

B IT L

In this country the brown-coal
is represented by the strata of
bituminous wood, called Bovey-
coal, which exhibits a series of
gradations from the most perfect
ligneous texture to a substance
nearly approaching the characters
of pit-coal.

BBU'CTTE. Called also Chondrodite
and Hemiprismatic Chrysolite.
This mineral was named Brucite,
after Bruce, an American mineral-
ogist; it occurs massive and in
small grains ; colours from a pale
yellow to a brownish red ; it
possesses a vitreous lustre, is
translucent, with a fracture im-
perfectly conchoidal. It contains
a small portion of fluoric acid, and
scratches glass. It is found in
America, Scotland, and Finland.
It consists of magnesia, silica,
fluoric acid, about four per cent,
oxide of iron, potash, and water.

BRYOZO'A. See Polywa.

BucA'iiDitrM. An acephalous bivalve,
having powers of locomotion.

BT^CCAL. (lucca, Lat. the cheek;
luccale, Fr. as glaudes luccales,
art&re luccale. j. Pertaining to the
cheek.

BU'CCINUM. (buccinum j Lat.) The
whelk. An ovate elongated uni-
valve ; opening oblong, notched in
the lower part, and with no canal ;
columella convex, full and naked.
— Parkinson.

Linnaeus places this genus, the
Buccinum, or Whelk, in the order
Gasteropoda, class Mollusca : it
comprises all the shells furnished
with an emargination inflected to
the left, and in which the columella
is destitute of plicae.. Many fossil
species have been discovered, the
greater number in the crag ; some
in the London- clay; six species
have been found in the environs of
Paris. De Blainville places the
buccinum in the family Ento-
mostomata. The greater part of
this genus may be considered

littoral; they are found however at
depths varying to ten fathoms.

BT/CCINITE. The fossil remains of
the luccinum. The greater part of
the genus buccinum is littoral.

BUCCINOI'DA. The third family in
the order Pectinibranchiata, divi-
sion Mollusca.

B'UCKLANDITE. (So named, by Levy,
after Prof. Buckland.) This rare
mineral, like Babingtonite, occurs
at Arendal, in Norway,- and was
distinguished and described by
Levy. It is of a dark brown or
nearly black colour, opaque, having
a vitreous lustre with an uneven
fracture. It greatly resembles
augite.

BU'FONITE. (from lufo, Lat.) Fossil
teeth of fishes belonging to the
family of Pycnodonts ; they occur
in great abundance throughout the
oolite formation. These bufonites
have been also called Serpent's -
eyes, Batrachites, and Crapaudines,
from the notion of their having
been formed in the heads of ser-
pents, toads, and frogs ; and, from
presumed virtues which it was
thought they possessed, they were
worn in rings and as amulets.

BTJLI'MUS. A fossil ovate or oblong
subturrited shell : the opening
entire, oblong, and longitudinal,
and this is the chief characteristic
of this genus. The bulimus is a
land shell. It is found both recent
and fossil. Many species have
been distinguished. — Parkinson.

BU'LLA. An ovate, gibbous, and
cylindrical univalve : the fossil
occuring in tertiary formations :
the spire not standing out, but
concealed : the opening the length
of the shell : the lip acute. The
recent bull a is marine, and found
in sands and sandy mud, at depths
varying to twelve fathoms. — Par-
kinson. De la Beche.

BU'LLITE. The fossil remains of the
bulla.

BUN

[63]

C A C

BTJMA'STTJS. (from ftov^aa-To-s, ex /3oi>
et /ia<rTos, Gr.) The name given
by Sir K. Murchison to a genus of
trilobites, who describes one species
only, which he has named B.
Barriensis, the specific name being
derived from the locality where it
was found, near Barr, in Stafford-
shire. The generic characters of
Bumastus are thus given by Sir R.
Murchinson in his splendid work
The Silurian System: "Pars ante-
rior capitis rotundato-convexa, sub-
SBqualis : oculis lunatis, glabris,
remotis. Pars costalis s. corpus
sulcis longitudinalibus vix appar-
entibus, costis decem. Pars pos-
terior maxima, rotundato-tumida,
aequalis." This remarkable crus-
tacean, says the same author, has
been hitherto known in England as
the Barr trilobite, having been
found near the village and beacon
of Barr, in Staffordshire. A very
large specimen of it, five inches
long by 3j inches wide, has been
lithographed.

BUNT. In conchology, an increasing
cavity ; a tunnel.

BTTNTEE SANDSTEIN. The name given
by the Germans to an extensive
arenaceous formation of red and
variegated stones, composing one
of the sub-divisions of the Red
Sandstone group. In Germany,
this formation is distinctly separated
from the Keuper by the Muschel-

kalk or shelly limestone. The
Bunter Sandstein of the Germans
is the same as the Gres bigarre
of the French, and the New Red
Sandstone of English geologists.
See New Red Sandstone.

BTJBEH-STONE. This word is some-
times written luJir-stone. Mill-
stone. The substance of burrh-
stone, or mill-stone, when unmixed,
is pure sllex; it has generally a
reddish or yellowish colour, but
that of the best quality is nearly
white; it is full of pores and
cavities, which give it a corroded
and cellular appearance. Burrh-
stone is a vesicular and corroded
variety of common quartz. It has
been hitherto found only in France.

BTSSACAN'THUS. A genus of fossil
ichthyolites of the Old Red Sand-
stone, described by Agassiz in his
Poissons Fossiles.

BYSSOA'ECA. A genus of bivalve con-
chifera, assigned by Swainson,
belonging to the family Arcacea.

BY'SSFS. (from /Jvo-o-os, Gr.) A
beard, as in the mytilus and pinna.
The lyssus is peculiar to bivalves.

BT'SSOLITE. (from fivffcro?, flax, and
\i0os, a stone.) So named by

- Saussure. A rare mineral, occur-
ring massive, in short, delicate,
and stiffish filaments, of an olive-
green, or brownish colour, with a
silky lustre, a variety of asbestiform
actinolite.

C

C'ACHOLONQ. (called also mother of
pearl opal : the quartz-agathe
cacholong of Haiiy ; the silex
cacholongof Brongniart.) A milk-
white variety of quartz, having a
pearly or glistening lustre, a flat
conchoidal fracture, and perfect

opacity. It is found on the river
Cach, in Bucharia, where it occurs
in. loose masses, and obtains its
name from that river, and cholong,
the Calmuc word for stone. It is
said by Brongniart that fas cacholong
has been found in calcareous breccia

C A L

[ 64]

C A L

in France. Prof. Jameson places
cache-long as a sub-species of opal,
stating that it is distinguished from
calcedony by lustre, fracture, hard-
ness, and specific gravity. Prof.
Cleaveland, however, deems it a
variety of calcedony, as do Messrs.
Phillips and Allan. Its specific
gravity is from 2-2 to 2'27. It
is opaque or slightly translucent at
the edges. Fracture flat conchoidal.
Infusible before the blow-pipe.

CA'DMITJM. A metal of a blueish-white
colour, with a specific gravity of
8-6. It is the least malleable and
ductile of all metals which possess
those properties. It was discovered
by Prof. Stromeyer, of Gottingen,
in 1 8 1 7, in some oxide, or carbonate,
of zinc ; it has subsequently been
found in the silicates of zinc of
Derbyshire, and in ores of that
metal found in other situations.
The equivalent number of cadmiun
is 52'5 ; its symbol Cd. Cadmium
has not as yet been usefully em-
ployed in the arts.

CADU'CT-BRAN'CHIATE. (from caducus,
perishable, and Iranchia, a gill.)
A term applied to certain amphibi-
ous animals, as the frog, toad,
newt, &c., who, at a certain period
of their existence, undergo a species
of metamorphosis, their gills, or
branchiae, becoming obliterated, and
their lungs developed.

CADU'COUS. (caducus, Lat.) In
botany, applied to leaves falling
before the end of summer ; to
corollas falling off before the drop-
ping of the stamens ; to perianths
falling before the corolla is well
unfolded.

CAIRN. (Gael.) A name given to a
heap of stones covering a dead body.

y u rf

CAIRN-GORM. j

CA'LATTE. Called also odontalite and
mineral turquoise : the uncleavable
azure spar of Mohs. This earthy
mineral has no cleavage. Hard-
ness = 6. Specific gravity =

2*8 — 3. Massive disseminated;
colour blue or greenish-blue passing
into sky-blue and into apple-green.
Streak white. Feebly translucent
on the edges, or opake. Fracture
conchoidal. The Russian chemist
John states calaite to consist of
alumina 73; oxide of copper 4 -5;
oxide of iron 4 ; water 18.
This mineral may be distinguished
from malachite, with which it has
sometimes been confounded, by its
yielding a white streak, while that
of malachite is green.

CA'LAMAR. A name given to the
cuttle-fish.

CA'LAMINE. (calamine, ^i.giallamina,
It.) Carbonate of zinc. Calamine
is found either loose, or in masses,
or crystallized; colour white, grey,
or yellow. Before the blow-pipe it
decrepitates, but does not melt.
It is used in the manufacture of
brass. It consists of oxide of zinc
65, and carbonic acid 34. It con-
tains also some sesquioxide of iron.

CA'LAMITE. (from calamus, Lat. /ca\a-
ytto5, a reed, Gr.)

1. A genus of fossil equisetacese.
Calamites abound universally in
the most ancient coal formations,
occur but sparingly in the lower
strata of the secondary series, and
are entirely wanting in the tertiary
formations, and also on the actual
surface of the earth. Brongniart
enumerates twelve species of cala-
mites. Calamites are characterized
by large and simple cylindrical
stems, articulated at intervals, but
either without sheaths, or present-
ing them under forms unknown
among existing equiseta ; they
however most differ from equiseta
in their height and bulk, sometimes
exceeding seven inches in diameter,
whilst that of a living equiseta
rarely exceeds half an inch. A
calamite fourteen inches in diameter
has lately been placed in the museum
at Leeds.

C A L

[65]

C A L

2. A mineral variety of hornblende,
called also Actynolite, or Actinolite.
See Actinolite.

CALC-SINTEB. Stalactitical or stalag-
mitical carbonate of lime. This is
so called from the German kalks,
lime, and sintern, to drop. It is
deposited from thermal springs,
holding carbonate of lime in solu-
tion.

CALCAI'BE GEO'SSIEE. (Fr.) A coarse
limestone, often passing into sand,
and abounding in marine shells ; it
contains by far the greater number
of the fossil shells which character-
ize the Paris basin. Kot fewer
than four hundred distinct species
have been found in a single locality
near Grignon. Dr. Berger observes
that this variety of limestone was
thought to be very scarce in
England, but that he is disposed to
believe, upon a further examination,
it will be found to occupy a great
extent of country. To M. Brong-
niart we are indebted for much
valuable information concerning
the calcaire grossier. The mean
specific gravity of specimens of the
calcaire grossier from different
parts of England, Dr. Berger gives
as 2-579, ranging from 2-466 to
2 '666. The calcaire grossier cor-
responds with our Bembridge series.

CALCAI'EE MOELLON. The name given
by M. Marcel de Serres to certain
marine beds of limestone found in
the south of France and comprised
in the supracretaceous group. The
calcaire moellon is commonly work-
ed as a building stone in the south
of France.

CALCAI'EE siLfcEUX. (Fr.) A com-
pact silicious limestone, occupying,
according to the early opinion of
Brongniart, the place of the calcaire
grossier where that is wanting,
who discovered in it the silicate of
magnesia. Like the calcaire gros-
sier, the calcaire siliceux belongs
to the eocene tertiary period ; it
has been found in the Paris basin,

in the Isle of Wight, and in
several parts of France.

CALCA'BEOTJS BOCX. Limestone.

CALCA'BEOUS SPAR. Crystallized car-
bonate of lime. Calcareous spar
occurs crystallized in a vast variety
of forms, but its primitive form is
invariably a rhomboid with obtuse
angles of 105°5', and 74°55', the
crystals break easily with the
stroke of a hammer. It consists of
nearly 57 parts of lime and 43
parts and a fraction of carbonic
acid. The finest specimens are
brought from Derbyshire, but it is
found in almost all parts of the
globe. Calcareous spar is often as
transparent as rock-crystal, but it
is usually coloured of various tints
by the presence of oxide of iron.
All its forms, which amount to
nearly 500, are derived from the
rhomb. When in irregular forms,
it may always be distinguished
from quartz by its admitting of
being scratched with a knife, and
by its effervescing when weak
nitrous acid is applied to it. Ice-
land spar is this mineral in its
purest form, and affords the readiest
means of observing the optical
phenomenon of double refraction.
Its almost universal diffusion is
probably owing to its partial solu-
bility in water ; in this condition
it niters through the crevices
abounding in all strata, and re-
crystallizes as the water evaporates.
When this filtration continues so
uninteruptedly as to prevent by its
mechanical action crystallization
from taking place, and yet so
gradually as to admit of the solid
mineral being deposited from the
water, those curious and beautiful
concretions called stalactites are
produced, which ornament, in so
singular a manner, most caverns in
rocks or mountains formed princi-
pally of limestone.

CALCA'BEOUS TTJPA. Beds of calca-
reous tufa are sometimes formed in

C A L

valleys, and at the bottom of lakes,
by a process which bears some
resemblance to chemical formations.
Springs containing carbonic acid,
that issue from limestone strata,
contain particles of carbonate of
lime chemically dissolved in water;
but on exposure to air and light,
the carbonic acid, which had but a
slight affinity for the particles of
limestone, separates, and the parti-
cles of lime are precipitated, and
form calcareous in crustations : these,
in the course of time, form beds,
and occasionally are of sufficient
hardness to be used for architectural
purposes. Thermal springs holding
in solution calcareous earth, rapidly
deposit beds of calcareous tufa.
At a temperature of 60° Fah., lime
is soluble in 700 times its weight
of water; if to this solution a small
quantity of carbonic acid be added,
a carbonate 'of lime is formed, and
precipitated in an insoluble state.
If, however, the carbonic acid be
in such quantity as to supersaturate
the lime, it is again rendered solu-
ble in water ; and it is thus that
carbonate of lime, held in solution
by an excess of fixed air, not in
actual combination with the lime,
but contained in the water, and
acting as a menstruum, is commonly
found in all waters. Hence it is
obvious, that a deposition of car-
bonate of lime from water may be
occasioned by either an absorption
of carbonic acid, or from the loss of
that portion which exists in excess.
CALC-DIABASE, A finely-grained, or
entirely compact diabase, with round
grains of calc-spar.

CALCE'DONY. } (calcedonius, Lat. calce-
CHALCE'DONY. ) doine, Fr. calcedonia,
It. Sometimes spelt chalcedony.)
The Gemeiner Kalzedon of "Werner.
Quartz agathe calcedoinoe of Haiiy.
Silox calcedoine of Brongniart. A
semi-transparent and translucent
variety of quartz, to which this
name has been applied, from its

[ 66 ] C A L

having been formerly found at
Calcedon. It is a simple, siliceous,
uncrystallized mineral. Flint nod-
ules are frequently calcedonic, the
calcedony occupying the hollows of
such flints, and being either mam-
millated, botryoidal, or stalactitical.
It has been observed that although,
in the present compact state of the
matter of flint, it is not easy,
though possible, to force a fluid
through its pores, yet it is probable
that before its consolidation was
complete, it was permeable to a
fluid whose particles were finer
than its own ; and that the particles
of calcedony, while yet in a fluid
state, being finer than those of
common flint, did thus pass through
the outer crust to the inner station
they now occupy ; and that these
particles of calcedony permitted a
passage through their interstices to
the finer particles of still purer
siliceous matter which, in the form
of crystallized quartz, are often
found crystallized in the centre,
enveloped both by calcedony and
common flint. "When flints contain
calcedony, there may generally be
perceived some small bubbles, or a
mammillated appearance, in some
part of the exterior of the flint:
between calcedony and flint there
is a near resemblance, being only
different modes of the same sub-
stance. Specific gravity 2*56.
There are several sub-species ; the
beautiful apple-green is called
chrysoprase; the grass-green va-
rieties, plasma; those with red,
brown, yellow, and green tints,
carnelian ; others are known as
heliotrope, jasper, onyx, agate, &c.;
these will all be described under
their several names, and in their
proper order. Of common calcedony
the most usual colour is grey, passing
into blue and brown by every in-
termediate variety. It is harder
than flint, and infusible before tho
blow-pipe without addition. When

C A L

[67]

GAL

calcedony is held between the eye
and the light, it is characterized by
a clondy or milky appearance,
resembling milk diluted with water.
Professor Jameson divides calce-
dony into four sub-species, namely,
common calcedony, chrysoprase,
plasma, and carnelian. Calcedony
was first accurately described by
Werner. Phillips says that onyx,
plasma, heliotrope, chrysoprase,
cacholong, carnelian, and agate,
are considered to be varieties of
calcedony.

CALCE'OLA. A fossil genus of bivalve
shells, belonging to the family
Bndistes of Lamark. It is equi-
lateral, very inequivalve, triangular,
the umbones are separated by a
large triangular disk in the lower
valTc; the hinge margin is straight
and dentated; the upper valve is
flat and semi-orbicular, forming a
kind of operculum to the lower,
which is much larger and deep.
Calceola is now generally regarded
to belong to the Brachiopoda.
The C. sandalina is found in the
Devonian system of rocks. — Lycett.

C'ALcrsATB. (calciner, Fr. cdctnarc,
It) To calcine; to burn by fire
to a calx, or friable substance.

CALCIC A'TIOX. (catenation, Fr. caUi-
nazumt, It) The reduction by the
action of fire of any substance to a
condition that it may be converted
into a state of powder.

CA'LCTJTE. (caltiner, Fr. caicinare, It.)
To burn by fire to a calx, or friable
substance.

C ALCITE. Another name for.calc-spar.

C^'Lcrrst. The metallic base of lime;
this metal was obtained by Sir H.
Davy from lime by means of
galvanic agency. Being received
during the process into a vessel
filled with naphtha, it was ex-
cluded from oxygen, and con-
sequently retained its metallic
appearance, which resembles that
of silver. But no further investi-
gations can be made, in the present

state of

perties as a metal,

lie air is admitted

regarding its pro-
U for the instant
to it,

it absorbs oxygen rapidly, bums
with an intense white light, and
re-produces lime, which is a prot-
oxide of calcium.

CALC-TUEF. A deposit of carbonate of
lime from calcareous springs. S«e
Calcareous Tufa.

CA'UX. \ (cvXaf, Gr. calix, Lat calict,

CA'LTX. >Fr. caUc^Ii.) The calyx,
or flower-cup, is the outer expanded
part, or external covering, of a
flower, generally resembling the
leaves in colour and texture; there
are seven kinds of calyxes, or
calyces, namely, periantheum,
amentum, spatha, gluma, iflvo-
lucrum, volva, perichsetium.

The calyx is the outer set of the
floral envelopes, when there are
more than one verticil of these. It
is composed of two at least, but
generally more, leaves, called sepals.
When the sepals are distinct, or
separate from each other, the calyx
issaidtobej»7y*4pa£n«. In many
plants the sepals are joined together,
more or less, by their edges, so as
to form one piece in appearance;
in this case the calyx is said to be
monosepabus. When all the sepals
are alike in size and form, the
calyx is said to be regular. When
the sepals vary in size or form, the
calyxissaidtobetmyidar. When
the calyx has one of its sepals
hollowed out into a long thin tube,
as in the larkspur, geranium, &c.,
it is said to be spurred. When the
calyx dies off soon after or im-
mediately on its expanding, it is
termed deciduous; this is commonly
the case with polysepalous calyces.
When the calyx survives the rest
of the flower, either enclosing or
forming part of the fruit, it is said
tote persistent: most monosepalous
calyces are persistent

GA'IUABD. A provincial name for a
fine grained silicious stone, a mem-

C A L

(.68 ]

CAN

ber of the coal series: it is used
for mending the roads, and often
exhibits films and encrustations of
coal. It is also called ganister and
galliard.

CALO'BIC. (from color, Lat. heat.)
An imaginary fluid substance, sup-
posed to be diffused through all
bodies, the sensible effect of which
is termed heat.

CALOEI'METEB. An instrument for
measuring the degree of caloric.

CALP. A sub-species of carbonate of
lime ; an argillo-ferruginous lime-
stone. The name given to a mem-
ber of the Irish carboniferous series;
it consists of black limestones.

CALY'MENE. (from /ce/caXv/i/ieV?/, Gr.
concealed.) A genus of trilobites,
which appears to have been anni-
hilated at the termination of the
carboniferous strata. Fossils of this
family were long confounded with
insects under the name of Ento-
molithus paradoxus. The following
is M. Brongniart's description of
Calymene : " Corps contractile, en
sphere presque hemicylindrique.
Bouclier portant pulsieurs tubercles
ou plis, deux tubercules oculiformes
reticules. Abdomen et post abdo-
men a bords entiers, T abdomen
divise en douze ou quatorze articles.
Point de queue prolongee." The
Calymene has also been called the
Dudley fossil : several species have
been described ; six are figured in
Sir R, Murchison's Silurian Sys-
tem, namely, C. Elumenbachii, C.
Downingeoe, C. Tuberculata, C.
Macropthalma, C. variolaris, and
C. Punctata. The last of these is
stated to have been found in the
lower, the other five in the upper
Silurian rocks.

CALI'PTRA. (Kakvinpa, Gr. calyptra,
Lat.) The calyx of mosses, accord-
ing to some writers. In the mosses,
the organs of reproduction consist
of sporules, contained within an
urn, or theca, placed at the top of
a thin stalk : this is closed with a

lid, called an operculum, and that
again is covered with a hood termed
a cdlyptra.

CALYPTEE'A. A fossil conoidal uni-
valve, with the apex entire, erect,
and somewhat pointed, the cavity
furnished with a spirally convoluted
lip ; also recent. — Parkinson.

CA'MBIUIT. (cambium, Latin.) In
botany, a juice exuded between the
bark and the alburnum, supposed
to serve the purpose of nourishing
the fibres of the leaf buds.

CA'MBEIAN. (from Cambria, a name
for the principality of "Wales.) A
name given by Professor Sedgwick
to a group of rocks, placed below
the Silurian, from their being
largely developed in Worth Wales ;
they principally consist of slaty
sandstone and conglomerate. The
Cambrian rocks belong to the
Grawacke group, and geology owes
much to Professor Sedgwick for
the valuable information he has
supplied in relation to them. The
Cambrian strata are not only con-
terminous with the Silurian system,
but are in several parts seen to rise
from beneath its lowest beds, and
to unite with them.

CAMPA'NULATE. (from campanula,
Lat.) Bell-shaped; in the form of
a bell. A term applied to the
calyx or corolla.

CAMPANULA'BIA. A zoophyte, found
abundantly on our shores, and thus
named from its bell-shaped cells
placed on footstalks.

CANALI'CTJLATED. (from canaliculatus,
Latin.) Channelled; furrowed;
made like a pipe or gutter. Applied
to any distinct groove or furrow in
shells.

CANCELLA'BIA. A genus of shell com-
prising many species. It is an ovate,
or subturrated univalve, with the lip
internally sulcated; the base of the
opening slightly channelled. The
columella having sharp, but com-
pressed, plicae. Fossils of this genus
have been found in the London

CAP

[69 ]

C A 0

clay and calc-grossier of Paris.
The recent cancellaria is found in
sandy mud at depths varying from
5 to 15 fathoms.

CANCELLATED, (from cancelli, lattice-
work, Lat.) Cross-barred; marked
with lines crossing each other. In
conehology, surrounded with arched
longitudinal ribs.

CA'NDLE-COAL. j Called also splint or

CA'NNEL-COAL. ) parrot coal. (This
substance has probably obtained its
name from the bright flame, un-
mixed with smoke, which it yields
during combustion, lighting a room
as with candles, candle being pro-
vincially pronounced cannel.} Can-
dle, or cannel, coal is a bituminous
substance, next in purity to jet.
It is black, opaque, compact, and
brittle; breaking with a conchoidal
fracture. Cannel-coal does not
soil the fingers when handled, is
susceptible of polish, and is capable,
like jet, of being worked into trin-
kets and ornaments. The difference
between jet and cannel-coal appears
to consist entirely in the presence
or absence of foreign earthy matters.
When these are absent, or exist in
minute proportion only, the bitu-
minous mass is so light as to float
on water, and then the term jet is
properly applicable ; but when the
presence of foreign earthy matters
is considerable, and the mass is
specifically heavier than water, and
dees not readily manifest electric
properties, it is with more propriety
termed cannel-coal. According to
Dr. Thomson, cannel-coal contains
21-56 of hydrogen, whereas New-
castle coal contains only 4*18 per
cent. "Cannel coal never manifests
internally any traces of vegetable
structure, but sometimes bears on
its surface evident marks of im-
pressions formed on it whilst in a
soft state." — Parkinson*

CAPRI'NA. A genus of fossil bivalve
shells belonging to the family
Rudistes of Lamark. M. D'Orbigny

has separated this genus from Di-
ceras (see that genus). One species,
the C. inoequirostratus, is recorded
from the chalk of Norfolk. — Lycett.

CAPHO'TINA. (See Dicer as.} A genus
established by M. D'Orbigny. The
C. Lonsdalei is found in the lower
green sand near Calne, in Wiltshire.
— Lycett.

CAPSA. A genus of transverse, equi-
valved, close shells, of the order
Nymphacece ; the hinge has two
teeth on the right valve, and one
on the left; there are no lateral
teeth ; ligament external.

CA'PSTONE. The name for a fossil
echinite, or that genus of eehinite
known as conulus.

The capstone, thus called from
its supposed resemblance to a cap,
rises from a circular base into a
cone, with an acute or obtuse
vertex, from which five pairs of
punctuated or crenulated lines
pass, dividing the shell into five
large and five small areas, that in
which the anal aperture is placed
being rather the largest. — Parkin-
son.

CA'PSULE. (capsula, Lat. capsule, Fr.)

1. In botany, a membranous or
woody seed vessel, internally con-
sisting of one or more cells, splitting
into several valves, and sometimes
discharging its contents through
pores or orifices, or falling off
entire with the seed.

2. A membranous or ligamentous
bag.

CAOTJ'TCHOTJC.

1. Vegetable caoutchouc, called
also elastic-gum, and India-rubber,
is the milky exudation from certain
trees, more especially the Hsevea
caoutchouc and the latropha elas-
tica, but it is obtained from several
others.

2. Mineral caoutchouc. A bitu-
minous fossil, elastic when soft,
but brittle when hard. It was
discovered in 1786 near Castletown
in Derbyshire. In its appearance

CAR

[70]

CAR

it miich resembles India-rubber,
whence it has obtained its name.

CA'BAPACE. The upper shell of
reptiles.

CAEADOC SANDSTONE, The name given
to a formation constituting the
upper member of the Lower Silurian
Rocks. " The name has been
selected, says Sir R. Murchison,
because the strata of which it is
composed constitute a number of
eminences, which abut against the
remarkable chain of trap hills
called the Caradoc * Unlike the
sandstones of the upper Silurian
rocks, this formation is composed
essentially of sandstones of different
colours, with an occasional subor-
dinate course of calcareous matter.
The Caradoc sandstone formation
is made up of beds of red, green,
and purple sandstones, some of
which it is difficult, upon first
inspection, to distinguish from
strata of the old, or even the new
red sandstone. Its best and clear-
est distinctions consist in its order
of infra- position to the upper Silu-
rian rocks, and in its organic
remains, nearly all of which are
dissimilar from the fossils of the
formations which immediately over-
lie it.

Among the fossils characteristic
of this formation may be enume-
ted Productus sericeus ; Bellero-
phon bilobatus and Bellerophon
acutus ; Littorina striatella ; Orthis
alternata ; Orthis collactis, and
Orthis canalis ; Pentamerus loavis
and Pentamerus oblongus. The
trilobites common to the upper
Silurian rocks are here wanting,
and instead are found other forms,
including the Trinucleus, a genus
not observed in the upper but
abounding in the lower Silurian
rocks : also a large species of
Asaphus, named by Sir R. Murchi-
son Asaphus Powisii. In other
beds of this formation there are
found Avicula orbicularis and

Avicula obliqua ; Orthis actonia,
and Orthis grand is ; Orthis Ano-
mala ; Orthis vecten ; Orthis flabel-
lulum; and Orthis vespertilis; Tere-
bratula anomala, and Terebratula
anguis ; Pentamerus oblongus, and
the plumose coral Calamopora
fibrosa.

Malachite, or the green carbon-
ate of copper, occurs in films and
nests. Thin strings of galena,
with some associated crystals of
blende, have been also found. For
a full description of this formation,
together with illustrations of the
contained fossils, the reader is
referred to SirR. Murchison's splen-
did work on the Silurian System,
from which the above is principally
extracted.

CA'EBON. (ca/rbo, Lat. carlon, Sp.
carlone, It. charlon, Fr.) Caradoc
limestone. The pure inflammable
principle of charcoal. If a piece
of wood, or any vegetable matter,
be placed in a closed vessel, and
kept red-hot for some time, it is
converted into a shining black
brittle substance, possessing neither
smell nor taste, commonly known
as charcoal. Charcoal is infusible,
insoluble in water, is capable of
combining both with hydrogen and
sulphur, is a conductor of electri-
city, and has a powerful affinity
for oxygen. Carbon is obtained
nearly pure in charcoal ; but, what
is astonishing, the diamond appears
to be this elementary substance in
its purest known form. Why it
is, or how it is, that the same
elementary substance can, with
little or no addition, form two
bodies so dissimilar in every re-
spect as charcoal and diamond, the
one a soft, black, brittle mass, the
other the clearest and hardest body
we know of, is a mystery beyond
our weak comprehensions to under-
stand. Carbon enters as a consti-
tuent part into many of the slate
rocks, to which it generally com-

CAB,

[71]

CAB

municates a dark colour : it forms
also regular beds of considerable
thickness, being the principal con-
stituent part of coal. Of Newcastle
caking coal it constitutes 75-28 per
cent., of cannel coal 64' 72 per cent.
The carbon in the atmosphere is
not considerable, but without it
vegetation could not exist. Saus-
sure ascertained that 10,000 parts
of atmospheric air contained, as a
mean, 4.9 of carbonic acid. Com-
bined with oxygen, carbon forms
carbonic acid or fixed air.

CA'RBONATE. A combination of car-
bonic acid with a base. Carbonic
acid is capable of combining with
earths, oxides, and alkalies, and
to these combinations the term
carbonate has been applied ; thus
we have the carbonate of lime,
carbonate of magnesia, carbonate of
lead, carbonate of iron, carbonate
of ammonia, &c., &c., &c.

CA'RBONATE OF LIME. A union of
carbonic acid and lime, consisting
of 57 parts of lime and 43 of
carbonic acid. The form of the
integrant molecule of carbonate of
lime was decided by the Abbe
Haiiy to be an obtuse rhomboid.
This conclusion was implicitly
adopted by mineralogists, till the
Count de Bournon announced the
discovery of cleavages passing
through the long diagonal of its
rhomboidal faces, and maintained
that the form of its integrant
molecule was a trihedral prism with
inclined bases. Dr. Brewster has
since satisfactorily proved that the
cleavages obtained by Co ant Bour-
non exist only in those specimens
which are crossed by interrupting
veins, and therefore that the tri-
hedral prism is not, but that the
obtuse rhomboid is the form of the
integrant molecule of carbonate of
lime. Carbonate of lime, under
the several names of chalk, lime-
stone, marble, &c., is found most
abundantly throughout nature. All

limestones effervesce when a drop
of strong acid is thrown on them,
and they entirely dissolve in nitric
or muriatic acid.

It is a difficult problem, says
Professor Buckland, to account for
the source of the enormous masses
of carbonate of lime that compose
nearly one eigth part of the super-
ficial crust of the globe ; some have
referred it entirely to the secretions
of marine animals ; an origin to
which we must obviously refer
those portions of calcareous strata
which are composed of comminuted
shells and corallines ; but until it
can be shown that these animals
have the power of forming lime
from other elements, we must
suppose that they derived it from
the sea, either directly, or through
the medium of its plants. [The
presence of carbonate of lime in a
rock may always be ascertained by
applying to the surface a drop of
diluted sulphuric, muriatic, or
nitric acids : the lime having a
stronger affinity for any one of
these than for the carbonic acid,
unites itself immediately with
them, and the carbonic acid being
liberated escapes in a gaseous form,
frothing up or effervescing as it
makes its way in small bubbles.]
CARBONIFEROUS GROUP. | Thecarboni-
CA'RBONIFEROUS SERIES, j ferous group
or series comprises the coal mea-
sures, the mountain or carboniferous
limestone, and the old red sand-
stone. The rocks of this group, says
Sir C. Lyell, consist of limestone,
shale, sandstone and conglomerate ;
interstratified with which are large
beds of coal. Several hundred
species of plants have been found
in the shales and limestones associ-
ated with the coal, all of which
are, with few exceptions, of species
differing widely from those which
mark the vegetation of other eras.
It is in this formation chiefly, that
the remains of plants of a former

CAB

[72]

CAR

world have been preserved and
converted into beds of mineral coal.
The most characteristic type that
exists in this country of the
general condition and circumstan-
ces of the strata composing the
great carboniferous order, is found
in the north of England. Accord-
ing to Mr. Forster's section of the
strata from Newcastle-upon-Tyne
to Cross Fall, in Cumberland, it
appears that their united thickness
along this line exceeds 4,000 feet.
This enormous mass is composed of
alternating beds of shale, sandstone,
limestone, and coal.

The above group constitutes in
the Rev. J". Conybeare's arrange-
ment the Medial order ; he says
" this series of rocks is by some
geologists referred to the flcetz, by
others to the transition class of the
"Wernerians; we have preferred
instituting a particular order for
its reception, a proceeding justified
by its proportional importance in
the geological scale, its peculiar
characters, and the many inconve-
niences arising from following
either of the above conflicting
examples."

Sir R. Murchison in his splendid
work " The Silurian System," says
" Being convinced that the Old
Red Sandstone is of greater magni-
tude than any of the overlying
groups, I venture for the first time
in the annals of British geology to
apply to it the term system, in
order to convey a just conception
of its importance in the natural
succession of rocks, and also to
show, that as the carboniferous
system, in which previous writers
have merged it, (but from which it
is completely distinguishable, both
by zoological contexts and litholo-
gical characters) is surmounted by
one- red group, so it is underlaid by
another, this lower red group
being infinitely thicker than the
upper."

Mr. Mushet, from a careful ex-
amination of the Forest of Dean,
has given a list of the various beds
of the coal measures, carboniferous
limestone, and old red sandstone,
constituting a mass of 8,700 feet
in thickness : the coal measures
being 3060 feet in depth. The whole
reposes on the grauwacke limestone
of Long Hope and Huntley.

CAEBONIFEKOTJS LIMESTONE. The name
proposed by Mr. Conybeare to be
given to mountain limestone. See
Mountain Limestone.

CABBO'NIC ACID. A compound of
carbon and oxygen ; it has been
called aerial acid, fixed air, creta-
ceous acid, and mephitic gas.
Carbonic acid is very plentifully
disengaged from springs in almost
all countries, but especially near
active or extinct volcanoes. This
elastic fluid has the property of
decomposing many of the hardest
rocks with which it comes in con-
tact, particularly that numerous
class in whose composition felspar
is an ingredient. In volcanic
countries these gaseous emanations
are not confined to springs, but
rise up in the state of pure gas
from the soil in various places.
The Grotto del Cane, near Naples,
affords an excellent example. The
acid is invisible, is specifically
heavier than atmospheric air, and
on this account accumulates in
any cavities on the surface of the
ground. It may be dipped out of
any excavations in which it has
accumulated, poured into a bottle,
like water, corked, and carried to
any distance. It is fatal to human
life when breathed undiluted, and
by the miners it is called choke-
damp. Carbonic acid gas is evolved
abundantly in coal pits. M.
Bischof calculates that the exhala-
tion of carbonic acid gas, in the
vicinity of the lake of Laach,
amount to 600,000 pounds daily,
or 219,000,000 pounds in a year.

CAR

[ 73]

CAR

CA'EBURET. A compound formed by
the combination of carbon with
any metal, alkali, or earth.

CA'EBUBETTED HYDROGEN GAS. The
fire-damp of miners.

CA'BBUNCLE. (carlunculm, Lat.) A
precious stone, supposed by some
authors to be the ruby, by others
the garnet ; called by the Greeks
anthrax.

CA'BDIAC. j (from Kapdi'a, the heart,

CABDI'ACAL. ) Gr. cardiaqiie, Pr.)
Relating to the heart, as the cardiac
nerves, &c.

CABDIA'CEA. In Cuvier's arrange-
ment a family of bivalves of the
class Testacea, comprising Yeneri-
cardia, Cardita, Cardium, Cypri-
cardia, and Trocardia.

CABDINIA. A genus of fossil bivalve
shells separated by M. Agassiz
from the unios ; Cardinia is thick,
equivalve, inequilateral, rather
compressed, and transverse ; the
hinge is remarkable for the size,
prominence, and lengthened form
of the lateral teeth. The species
of cardinia are numerous, five are
recorded from the coal measures,
nine from the lias, and two from
the inferior oolite in England. —
Lycett.

CABDIOMOBPHA. A genus of fossil
bivalve shells, hitherto found only
in the carboniferous limestone. M.
Koninck describes it as being
equivalve, inequilateral, thin, ob-
lique, and transversely elongated ;
the hinge without teeth, linear,
with a smooth cardinal lamina
extending from the umbones to
the extremity of the margin ; the
ligament linear and external.
Dublin, Holland, Kildare and Yise
are given as the localities. One
species only is known, the
C. oblonga. — Lycett.

CARDI'TA. An inequilateral bivalve,
found at various depths to thirteen
fathoms, in mud and sands ; some-
times attached to stones. The
hinge with two unequal teeth;

the hinge tooth the shortest, be-
neath the beak ; the other longitu-
dinal, beneath the insertion of the
cartilage. Lamarck places Cardium
in the family Cardiacea.

CA'BDIUM:. The cockle ; animal a
tethys. A genus of bivales, the
shells of which are characterised
by the teeth of their hinge, and by
the projection of their beaks ; the
latter giving them a cordiform
appearance. They are generally
ornamented with longitudinal rid-
ges, and frequently with stride,
scales or spines. The different
species are found at depths varying
to thirteen fathoms, in mud, sands,
and gravel. This genus belongs to
the class Yermes, order Testacea.
Many of the species, as the C. acu-
leatum, arcuatum, ciliare, discors,
edule, elongatum, Iffivigatum, no-
dosum, spinosum, &c. &c. are found
on our coasts. The cardium, with
the exception of one species, car-
dium fluviatile, has only been found
to inhabit the ocean; generally
they live just under the surface of
the sand. Fifty-two species have
been described.

CABI'NA. (Lat.) The keel ; a term
applied to two of the petals in
papilionaceous flowers. The ca-
rina is composed of two petals,
separate or united, and encloses the
internal organs of fructification.

CABINA'BIA. A very thin univalve,
in the form of a cone flattened on
its sides, the apex terminating in a
very small convoluted spire, and
the back having a dentated keel.
De Blainville places Carinaria in
the family Wectopoda. It derives
its name from its dorsal keel.
Parkinson states that it has not
been found fossil, nor is its inhabi-
tant known. Sowerby mentions
that this beautiful shell was once
so rare, that a specimen would
fetch one hundred guineas.

CA'BINATED. (carinatus, Lat). Keel-
shaped ; in conchology, having a

CAR

[ 74 ] CAR

longitudinal prominence like the
keel of a vessel.

CAEIN'THINE. A variety of horn-
blende, of a dark green or black
colour. It obtains its name from
being found in Carinthia.
CAEN. ) The name assigned to small
KAEN. j round hills in some parts
of England; in others these are
called tors. Carn-Marth and Carn-
Brea are two small hills near
Eedruth, in Cornwall.
CAENA'EIA. (carnarius, Lat.) Flesh-
eating animals. In Cuvier's ar-
rangement, the third order of
Mammalia.

CAENE'LIAIT. j (cornaline^i.cornalina,
CAENE'LION. j It. The Karneol of
Werner, Quartz-agathe Cornaline
of Haiiy.) A precious stone of
various colours, as red, brown,
yellow, and white. It is a variety
of rhombohedral quartz. The finest
specimens are brought from India.
Carnelian is composed of 94 parts
silica, 3*50 alumina, and a trace of
oxide of iron. Carnelian differs
from calcedony only in being more
or less transparent. It varies in
its constituents from being nearly
pure silex, to a mixture of this
earth with alumine and iron, in
small quantities. Some particulars
relative to the carnelians of Cambay
are given in a memorandum from
the minute book of the Geological
Society. " These carnelians are
all procured from the neighbour-
hood of Broach, by sinking pits
during the dry season in the chan-
nels of torrents. The nodules
which are thus found lie intermixed
with other rolled pebbles, and
weigh from a few ounces to two or
three pounds. Their colour when
recent is blackish olive passing
into grey. The preparation which
they undergo is, first, exposure to
the sun for several weeks, and then
calcination. This latter process is
performed by packing the stones in
earthen pots, and covering them

with a layer five or six inches
thick of dried goats' dung ; fire is
then applied to the mass, and in
twelve hours time the pots are
sufficiently cool to be removed.
The stones which they contain are
now examined, and are found to
be some of them red, others pink,
and others nearly colourless, the
difference depending partly on the
original quantity of colouring mat-
ter and partly on the difference of
heat applied."

CAENI'VOEA. (from caro carnis, and
voro, Lat.) 1. Animals which subsist
solely on flesh. They belong to
the third order, class "Mammalia.
This order is divided into three
families, Digitigrada, Plantigrada,
and Pinnigrada.

CAENI'VOEOFS. (carmvorus, Lat. carni-
vore, Fr.) Living on flesh; de-
vouring flesh.

CA'EOTID. (from Kaptorides, Gr. caro-
tides, Lat. carotides Fr.) The name
given to certain arteries of the neck.

CA'EPAL. (from carpus. Lat. icapi-os,
Gr.) "Relating to the wrist.

CAEPE'LLTJM. (from KapTros, Gr.) In
botany, a leaf in a particular state
of modification. Each modified
leaf which forms the pistil, is called
a carpellum, and has its under side
turned outwards, and its upper
inwards, or towards the centre of
the flower. The carpella are folded
so that the margins of the leaf are
next to the axis, or centre : from
these a kind of bud is produced,
which is the seed. On the form
of the carpella, on their number,
and on their arrangement around
the centre, depends, necessarily,
the form of the pistil.

CA'EPOLITE. \ (from Kap7ros,fructu8,

CA'EPOLITH. and \j6os, lapis.)

CAEPOif THUS. ) Any fruit which
by silification has been converted
into stone.

CABPO'LOGY. (from Kap7rb<$ and Xcfyo?,
Gr.) That branch of the science of
botany which treats of fruits.

CAS

CAT

CA'RTILAGB. (cartilago, Lat. cartilage,
Fr. cartilagine, It.) Smooth,
solid, animal matter, softer than
bone, and harder than ligament;
gristle,

CARTILAGINOUS. (cartilagineux, Fr.
cartilaginoso, It.) Consisting of
cartilage ; resembling cartilage ;
gristly.

2. A name given to all fish
whose muscles are supported by
cartilages instead of bones.

3. A term applied to leaves, the
borders of which are hard and
horny.

CARYOPHY'LLIA. " A stony fixed poly-
pifer, simple or ramified ; the stem
and branches rather turbinated,
and striated longitudinally, each
being terminated by a cell, radiated
in a stelliform figure. — Parkinson.
Lamarck separated Caryophyllia
from Madrepora. In the caryo-
philliae possessing more than one
cell, each receptacle contains a
polypus. A branched madrepore
with a star at the end of each
branch ; each star having a mouth
and tentacula. — Bakewell.

CA'SPIAN. The name given to a large
body of salt water not communi-
cating with the main ocean.
" Masses of salt water are some-
times included in the dry land,
which have been termed Caspians,
from the Caspian Sea, the largest
of them. These bodies of salt
water have been variously accoun-
ted for ; some supposing that they
have been left isolated by a change
in the relative level of land and
water, while others imagine their
saltness to arise from their oc-
currence in countries impregnated
with saline matter." — M. Le Beche,
Geological Manual.

CASSIDA'RJA. A genus of univalve
molluscs found both recent and
fossil. The recent species are
found near the shore, and at small
depths from the surface. The

fossil specimens occur in the terti-
ary strata.
CA'SSIS.

1. The helmet-stone. An echinite,
a section of the class of Catocysti.

2. A gibbose ventricose univalve ;
the aperture longitudinal and sub-
dentated, and terminating in a
short reflected canal. The colu-
mella plicated in its lower part ;
the left lip flattened, and forming
a ridge on the body of the shell. —
Parkinson.

This genus of shells is found
both recent and fossil : the recent
is an inhabitant of tropical seas ;
the fossil occurs in the tertiary
deposits. Some species are figured
in Parkinson's Organic Remains.

CA'SSIDITE. A fossil shell of the
genus cassidaria. The hills of
Tuscany yield these fossils.

CA'TACLYSM. (from /caTa/cXt/<r/tos, Gr.
cataclysmej Fr.) A great inunda-
tion or deluge: used generally to
describe the ^Noaohian deluge.

The sect of Stoics taught that
catastrophes were of two kinds;
the cataclysm and the eepyrosis;
the former sweeps from the face of
the earth the whole of the animal
and vegetable productions; the
latter destroys the globe itself.

CAT'S-EYE. The katzenange of Wer-
ner; quartz agathe chatoyant of
Hau'y ; quartz hyalin chatoyant of
Brongniart. A beautiful mineral,
a variety of rhombohedral quartz,
having an opalescence resembling
the light from the eye of the cat ;
whence its name. The peculiar
play of light arising from the
structure of this stone, is better
known than susceptible of descrip-
tion. The chatoyement of this
mineral ia supposed to arise from
fine fibres of asbestus or amianthus
included in it. This chatoyement,
or opalescence, is increased by the
mineral being cut in a spherical
form. The colours of cat's-eye are
greenish or yellowish-grey, yellow-

CAY

[ 76 ] GEL

ish-brown, reddish-brown, and
greyish-white, with intermediate
shades. The finest specimens are
brought from Ceylon. Cat's-eye is
harder than quartz, and consists of
silex 95, alumine 1'75, lime 1*25,
oxide of iron 0-25.

CATAEHINI. A family of the order
Quadrumana, comprising the mon-
keys of the old world.

CATILLUS. A genus of bivalve couchi-
fera, considered by some authors to
be identical with Inoceramus, but
is separated by M. Deshayes for
reasons apparently conclusive; it
is oval or oblong, nearly equivalve,
inequilateral, the umbones being
more or less prominent, the hinge
is straight, nearly perpendicular to
the longitudinal axis, its border
being furnished with a series of
small cavities; the shell is very
thick, sometimes of enormous di-
mensions, being mentioned as
attaining many feet in length ; the
structure of the test is fibrous. The
white chalk of France and England
has produced all the known species.
— Lycett.

CATO'DON. A name given to the
spermaceti whale. Of the genus
Catodon, Ray mentions a large one
stranded on the coast of Holland.

CATOCY'STI. The second great di-
vision, or family, of Echini. The
catocysti have the opening for the
vent in some part of the base of the
shell ; they are divided into fibu-
lae, cassides, scuta, and placentae.

CAifDA. (Lat.) In conchology, the
elongated base of the ventre, lip,
and columella.

CATT'DEX. (Lat.) The stock or trunk,
the stem or body of a tree.

C'AVEBNOUS (cavernosus, Lat. caver -
nem, Fr. cavernoso, It.) Full of
caverns and hollows.

CAWK. A name for sulphate of
barytes.

CA'YMAN. The name assigned to a
sub-genus of crocodiles. Authors
are not agreed as to the origin of

this name ; Rochefort says it was
original with the native islanders
of the Antilles.

CELA'CANTH. Hollow spine. A family
of fossils of the old red sandstone,
deriving their name of hollow-
spine from this peculiarity. — Hugh
Miller.

CELE'STINE. Sulphate of strontia, or
sulphate of strontites. It has
obtained the name of celestine from
being frequently found possessing
a blue colour ; but as it does not
invariably possess that colour, and
is often found either colourless or
red, the name appears to be inap-
propriate. It occurs both massive
and crystallised. It is composed
of 58 parts of strontia, and 42 of
sulphuric acid. It is found in
Scotland, in Yorkshire, and in
Somersetshire, near Bristol; also
in the neighbourhood of Paris, and
in Sicily, from which last place
we obtain the finest specimens.

CELLEPO'EA. Animals belonging to
the class Yermes, order Zoophytes.
Generic characters : — Animal an
hydra or polype ; coral somewhat
membranaceous, composed of cells.
Species : — The principal species are
the Cellepora pumicosa, annulata,
spongites, &c. — Crall.

CELLEPO'EITE. A fossil cellepora.
Seven species of celleporites have
been determined by Goldfuss as
belonging to the organic remains of
the cretaceous group : two other
species are found occurring in the
oolite, and two distinct species in
the grauwacke. Fossil celleporae
may be distinguished from fossil
flustrae, by their cells being urceo-
lated and irregularly placed, and
by the constricted appearance of
their mouths.

CE'LLULAE MEMBEANE. In anatomy,
that tissue of filmy meshes which
connects the minute component
parts of most of the structures of
the body.

C E

[77]

CEP

CE'LLLUAR INTEGUMENT. In botany,
the succulent pulpy substance
situated immediately under the
cuticle ; the seat of colour, mostly
green, particularly in the leaves or
branches. Leaves consist almost
entirely of this substance, covered
on each side by the cuticle ; the
stems and branches of both annual
and perennial plants are invested
with it. This tissue is membranous
and transparent : in its simplest
state, it appears like a mass of
globules or vesicles, crowded to-
gether ; these, by pressing against
each other, assume a six-sided, or
hexagonal, form. This cellular
tissue allows of the passage of
fluids, and is consequently porous,
but no pores or openings have been
discovered in it. Cellular integu-
ment is in itself colourless, but its
vesicles contain that colouring
matter which gives to the corolla
its brilliant colours, and to the
herbaceous parts of plants their
green.

CEMENTA'TION. (cementation, Er.)
1 . The act of uniting by means of
cement. 2. A chemical process
by which iron is converted into
steel ; glass into porcelain, &c.
This process is effected by surround-
ing the body to be acted on with
some other substance, as iron with
charcoal, and subjecting it to the
action of fire in a closed vessel.

CEMOR'IA. A genus of patelliform
univalve shells, separated by M.
Leach from Fissurella, on account
of its having the fissure placed
behind the apex, which is produced
and incurved. C. novehina has
been found in pleistocene marls at
Dalmuir, and in Sweden and
Norway. — Lycett.

CENTIFO'LIOUS. (from centum and
folium, Lat.) Having a hundred
leaves.

CENTRE OF GRAVITY. A point in
every body, which if supported,
the body will remain at rest, in

whatever position it may be placed.
Above that point, all the Jparts
exactly balance one another. The
centre of gravity of the solar
system is within the body of the
sun, because his mass is much
greater than the masses of all
the planets and satellites added
together.

CENTRIFUGAL, (centrifugo, It. centri-
fuge^?. Terme de Physique. Un
corps qui se meut en rond, d une
force centrifuge.) That power
which bodies in rapid rotatory
motion acquire of flying off from
the centre. The force with which
a revolving body tends to fly from the
centre of motion : a sling tends to fly
from the hand in consequence of the
centrifugal force. The centrifugal
force arising from the velocity of
the moon in her orbit, balances the
attraction of the earth. The di-
mensions of the earth being known,
as well as the time of its rotation,
it is easy thence to calculate the
exact amount of the centrifugal
force, which, at the equator,
appears to be = 2J9th part of the
force or weight by which all bodies,
whether solid or liquid, tend to
fall towards the earth.

CENTRI'PETAL. (centrvp&te, Fr. Qui
tende dpproelier d'un centre. Les
planbtes ont une force centrip&te vers
le soleil.) The contrary power to
centrifugal, for while the one
drives, as it were, the surrounding
bodies from the centre, the other,
the centripetal, attracts and holds
them to it.

CEPHALAS'PIAN. Relating to the ce-
phalaspis ; resembling the cephalas-
pis. "The remains of a large
cuirassed fish of the cephalaspian
type."— Hugh Miller.

CEPHALA'SPIS. (from Ke0aXiJ, a head,
and aairls, a buckler, buckler-head ;
pi. cephalaspides). A fossil fish
of the cornstone formation, so
named by Agassiz, from its head
being covered by a sort of shield,

CEP

[78]

C E R

having the bones united into one
osseous case : in form, this fish
hears a resemblance to the elonga-
ted trilobites of the transition rocks.
Of the genus cephalaspis Agassiz
established four species, namely,
C. Lyellii, C. rostratus, C. Lewissii,
and C. Lloydii. Of these four
species, the first is found most
abundantly in the red sandstone,
both of England and Scotland,
and is constituted the type of the
genus. An entire fish of the ce-
phalaspis Lyellii has been found in
the old red sandstone of Forfar-
shire, the head of this fish is very
large in proportion to the body,
and occupies very nearly one-
third of its whole length. The
outline is rounded, in the form of
a crescent, the lateral horns in-
clining slightly towards each other,
while the anterior and central
parts project much. The middle
of the head, including the region
of the eyes, the cranium, and the
occipital crest, is elevated, whilst
the sides and anterior edge are
considerably dilated and horizon-
tally extended. The eyes are
placed in the middle of the shield
and near each other, but a little
nearer to the end of the snout than
the occipital crest ; they appear to
have been directed straight up-
wards. The posterior and middle
portion of the head is nearly square,
and is edged by the first series of
scales. The C. Lloydii has a head
the least resembling that of a fish,
it occurs in the cornstone of Shrop-
shire, Worcestershire, Hereford-
shire, &c. Cephalaspis appears to
have formed the connecting link
between crustaceans and fishes ;
no existence of the present creation
at all resembles the cephalaspis.
CEPHALOPHOHA. The first class of the
sub-kingdom Mullusca. This class
has usually been called Cephalopo-
da, but, according to the classifica-
tion of Pictet, it is now divided

into six orders, namely, Dibran-
chiata, Tetrabranchiata, Pulmonata,
Pteropoda, Gasteropoda Dicecia,
aud Gasteropoda, Monoecia.
CEPHA'LOPOD. \ (from /ce0a\r}, head,
CEPHALOPODA. > and iro&es, feet,
CEPHALO'PODES. ) Gr.) A term
applied by Cuvier to a large family
of molluscous animals, from their
having the feet placed around their
heads, and walking with their heads
downwards. The feet are lined
internally with ranges of horny
cups, or suckers, by which the
animal seizes on its prey, and
adheres to extraneous bodies. The
mouth, both in form and substance,
resembles a parrot's beak, and is
surrounded by the feet. It is now
well established that the living
species of cephalopods which
possess no external shell, are pro-
tected from their enemies by a
peculiar internal provision, consist-
ing of a bladder- shaped sac,
containing a black and viscid fluid,
or ink, the ejection of which, by
rendering the surrounding water
opaque, conceals and defends them.
The sepia vulgaris and loligo afford
us familiar examples. — Buckland.
According to Prof. Phillips, the
following are the genera of Cepha-
lopoda : Bellerophon, Orthoceras,
Belemnite, Nautilus, Ammonite,
Edomite, Scaphite, Baculite, Num-
mulite. The only living species
belong to the genus Nautilus, of
which there are two.

The Cephalopoda, in the arrange-
ment of Cuvier, form the first class
mollusca, and comprise the follow-
ing genera, which he divided
according to the nature of the shell,
Sepia, Nautilus, Belemnites, Am-
monites, and Nummulites.
CEBAU'NII LA'PIDES. (from Kepawos,
Gr.) A name formerly given to
fossil echinites, from a supposition
that they were formed in the air.
CERATOPHI'TA. In Linnseus's ar-
rangement, an order, the 6th, of

C E

[79]

C E T

the class, Zoophytes, or animal
plants, comprising Gorgonia, Cor-
allium, Pennatula, &c. They have
a horny axis, covered with a fleshy
substance, from the cavities of
which polypi occasionally appear.

CEEEBE'LLUM. (Lat.) Dim. of cere-
brum; the little brain situate
behind the brain, or cerebrum.

CE'EEBETIM:. (Lat.) The brain.

CE'BEBEAI. | (cerebral, Fr. cerebrate,

CE'EEBBINE. ) It.) Belonging to
the brain : relating to the brain.

CEEIOP'OBA. The name assigned to a
genus of zoophytes.

CEEI'OPOEITE. A fossil ceriopora.
Twenty-one species have been de-
termined by Goldfuss, as occuring
in the cretaceous group ; nine
species have been found in the
oolite, and six in the grauwacke
group.

CE'EITE. The siliceous oxide of cerium.

CEEI'THHTM. A turreted or turricu-
lated univalve, with an oblique
opening. Lamarck has discovered
sixty fossil species of the genus
Cerithium in the neighbourhood of
Paris. The recent cerithium is
found at depths varying to seven-
teen fathoms, and it is stated that
so tenacious of life is at least one
species, the cerithium telescopium,
that a specimen sent from Calcutta
in sea water, lived out of water in
a tin-box for more than a week.
The recent cerithium has a veil
on its head, with two separated
tentacula.

CE'BITHITE. The fossil cerithium.

CE^BIUH. A metallic substance dis-
covered by Berzelius and Hissinger
in 1804. It was obtained from a
mineral called cerite, which was
formerly supposed to be an ore of
tungsten; it is also found in
allanite.

CE'EVIX. (Lat.) The neck.

CEBVI'CAL. (cervicalis, Lat. cervical,
Fr. cervicale, It.) Belonging to
the neck, as the cervical vertebra?,

the cervical muscles, the cervical
arteries.

CEBVI'COBRANCHIATA. In the con-
chological system of Be Blainville,
the name given to an order of
shells, comprising the two families
Ketifera and Branchifera, and the
genera Patella, Fissurella, Emar-
ginula, and Parmophorus.

CESTEA'CION. } InAgassiz'sTa-

CESTBA'CIONTS. PL. j bular View
of the Genealogy of fishes, the
Cestracionts, and they only, sweep
across the entire geological scale.
With this family, so far as is yet
known, ichthyic existence first
began. — Hugh Miller.

The Cestracions constitute a
family of fishes of the placoid order.
" It does not appear that on tho
globe we inhabit there was ever
an ocean, tenanted by living
creatures, that had not its ces-
tracion".— Hugh Miller.

The first and oldest sub-family
of sharks. The cestracionts have
only one living representative, the
Cestracion Philippi, or Port Jackson
Shark. The character of this sub-
family of sharks is marked by the
presence of large polygonal obtuse
enamelled teeth, covering the inte-
rior of the mouth with a kind of
tesselated pavement. In some
species, not fewer than sixty of
these teeth occupied each jaw.
They are rarely found connected
together in a fossil state, in conse-
quence of the perishable nature of
the cartilaginous bones to which
they are attached. They are found
abundantly dispersed throughout
all the strata, from the carboniferous
to the most recent chalk series.—
Buckland.

CESTEA'CIONT. Resembling a cestra-
cion; pertaining to a cestracion.
"This fish belongs to the cettraciont
family, of the placoid order." —
Hugh Miller.

CETA'CEA. Vertebral, warm-blooded
animals, living in the sea; they

C E Y

r

have no gills; there is an orifice on
the top of the head through which
they breathe, and eject water; and
they have a flat horizontal tail.
The cetacea breathe by means of
lungs, and this compels them to
rise frequently to the surface of the
water for the purpose of respiration ;
they also sleep on the surface. The
cetacea both bring forth their young
alive, and suckle them. Cetacea
constituted the ninth order of the
class Mammalia, and is divided into
six families, namely Zeuglodontidos,
Delphinidce, Monodontidoe, Hetero-
dontidce, Physeteridce, and Bal-
cenidce.

CETIOSAUBUS. A genus of extinct
reptiles, bearing some resemblance
to the cetaceans. The vertebrae
are almost circular at the ends, and
have a very short body ; the front
articulating surface is nearly flat,
and the other concave, in the dorsal
vertebrae, but in the caudal, both
ends are deeply hollowed; they
are often found eight inches in
diameter. The Cetiosauri must
have equalled the whales in bulk.

CETOSIS. A genus of fossil multilo-
cular shells having a stellated
opening at the pointed termination.

CETOTOLITE. (from K^TOS, a whale,
ws, an ear, and Xttfo's, a stone, Gr.)
The name assigned by Prof. Owen
to a fossil ear-bone of the whale.
" I have proposed to call the bodies
in question cetotolites, as they con-
sist of portions of the ear-bones of
large cetacea." — Prof. Owen.

C'EYLANITE. The pleonaste of Haiiy ;
zeylanite of Werner; ceylanit of
La Metherie ; candite of Bournon.
A dark green or black variety of
dodecahedral corundum. It occurs
in the sand of the rivers of Ceylon,
from which island it obtains its
name. Prom its being found in
the rivers and alluvial country
around Candy in the isle of Ceylon,
Bournon named it candite. Some
mineralogists place Ceylanite in

] C H A

the members of the ruby family.
By some it is regarded as a variety
of spinel, but its specific gravity is
higher, and it differs from spinel
as well in colour as in composition.
Ceylanite is found sometimes in
rounded grains, is often crystal-
lized in octahedrons, sometimes
with truncated edges ; also in
dodecahedrons with rhombic faces,
of which eight solid angles are
sometimes truncated. Specific
gravity, according to Haiiy, is from
3-76 to 3-79. It is of sufficient
hardness to scratch quartz. Struc-
ture indistinctly foliated ; fracture
shining and conchoidal, with large
smooth cavities.

It is nearly or quite opaque, its
common colour being of a dark
blue or nearly black, but its
fragments transmit a dark greenish
light.

It is met with in the drusy
cavities of certain lavas of Somma
and Vesuvius. According to the
analysis of Descotils, it consists of
alumina, 68'0, silica 2-0, magnesia
12'0, oxide of iron 16*0. Laugier
discovered 2'0 of lime in what he
analysed.

When met with in grains it may
be confounded with tourmaline,
but it may be distinguished from
tourmaline by its resinous lustre,
greater specific gravity, and by its
not becoming electric when heated.
La Metherie first established it as
a distinct species, and as such it
was subsequently acknowledged
by Haiiy and Werner.
CHA'BASITE. Ehombohedral zeolite,
The chabasie of Haiiy, and scha-
basit of Werner. A mineral of a
white colour, with sometimes a
rosy tinge. It occurs crystallized
and massive. It is composed of
silica, alumina, lime, potass, soda,
and water, silica forming about
fifty per cent, of the whole.
CHALA'ZA. (xaXa£o, Gr.) In botany,
a small swelling on the outside of

C H A

[ 81 ]

G H A

the seeds of some plants, it is some-
times coloured : the lemon and
orange afford examples of the
chalaza.

CHALCE'DONY. See Cakedony.

CHALK, (balk, Germ., the craie
blanche of the French.) A white
earthy limestone, composed of lime
and carbonic acid; a variety of
carbonate of lime. According to
M. Berthier, the chalk of Meudon,
when the sand disseminated in it
was separated by washing, con-
tained in 100 parts, — carbonate of
lime 98, magnesia and a little iron
1, alumina 1. It has an earthy
fracture, is meagre to the touch,
and adheres to the tongue ; it is
dull, opaque, soft, and light ; its
specific gravity being from 2.30 to
2.80. It contains an inconsidera-
ble proportion of silex and iron.
The harder varieties of this sub-
stance were formerly used for
building, and, when protected from
the influence of the atmosphere by
a thin casing of limestone or flint,
proved very durable. The ruins
of the Priory of St. Pancras, near
Lewes, which have stood nearly
800 years, prove this. — Dr Mantell.
The rock commonly known as
chalk preserves its peculiar mineral
character throughout a considerable
area in Europe, but it is rarely of
such thickness as in many parts of
the south east of England, where
horizontally stratified masses about
one thousand feet thick are compo-
sed of it. In proportion as we
depart from the great central deposit
of Europe, we find the chalk greatly
varying in its texture; in some
parts becoming oolitic.

Yarious conjectures have been
offered respecting the probable
origin of chalk, and the mode 'of its
formation. Patrin supposed that
it was the production of three
different causes. 1. Animal earth,
proceeding from the decomposition
of organic bodies. 2. Calcareous

lava, ejected by submarine volcanos.
3. Detritus of calcareous moun-
tains. Delametheric imagined it
to have been deposited by water in
a state of great agitation. Dr.
Mantell observes that it may have
been precipitated from water hold-
ing lime in solution, from which
an excess of carbonic acid was
expelled. Mr. Bakewell says,
" according to Eerrare, streams of
liquid chalk, or chalk in the state
of mud, were ejected from the mud
volcano of Macaluba, in Sicily, in
1777. If then we allow submarine
aqueous eruption of calcareous
matter, and siliceous solutions from
thermal waters, to have been poured
into a deep ancient ocean, we shall
have all the circumstances required
to form thick beds of chalk, inter-
spersed with nodules of flint. Mr.
Lonsdale, on examining some pieces
of chalk from various parts, found
what appear to the eye simply
white grains, were, in fact, well
preserved fossils. Erom each pound
in weight of chalk, he obtained
about 1,000 of these.
CHALK FOBMATION. This term is
applied in the nomenclature of
geology to a group of deposits
very dissimilar in their lithological
compositions, but agreeing in the
character of the organic remains
which they contain, and referrible
to the same epoch of formation, or
series of strata, of great depth,
which are spread over a large
portion of the eastern and south-
eastern counties of England,
northern Erance, Germany, Den-
mark, Sweden, European and
Asiatic Russia, and the United
States of North America. It
consists of strata that have been
accumulated in the depths of a sea
of vast extent, and affords a striking
illustration of the character of
oceanic deposits. Scarcely a trace
of chalk can be found in Scotland
or Wales, but it occurs in Ireland
M

C H A

on the north coast. The chalk
formation is composed of six di-
visions, namely, 1. The Maestricht
beds; 2. The upper chalk with
flints; 3. The lower chalk without
flints ; 4. The Upper green sand ;
5. The gault ; 6. The lower green
sand. Some authors divide the
chalk formation differently, con-
stituting the grey marl, which lies
between the chalk without flints,
above, and the firestone, or upper
green sand, below, a distinct mem-
ber. Others separate the green
sand formation from the chalk
formation, making the chalk marl
the lowest member of the chalk
formation, and placing the upper
green sand, or firestone, the gault,
and the lower green sand, in the
green sand formation. The whole
of these are marine deposits. It
must however be kept in mind that
this order is far from constant.
The members of the cretaceous
group are ranked as the last of the
secondary period; and, in the order
of superposition, are placed above
the wealden, and below the earliest
of the tertiary period, or eocene.
" In general, an interval seems to
have taken place between the com-
pletion of this formation, and the
deposition of those which repose
upon it; and the surface of the
chalk, at the line of junction,
usually bears marks of having
undergone, during that period, a
partial destruction subsequently to
its consolidation ; a bed of debris
being spread over it, consisting
chiefly of flints washed out of its
mass, and the surface being irregu-
larly worn into frequent cavities,
many of them of considerable depth,
filled with similar debris. On this
debris rests the plastic clay : here,
therefore, the transition from the
chalk to the more recent formations
appears to have been abrupt, not
gradual ; in a few instances, how-
ever, a bed of intermediate character,

[ 82 ] C H A

a cretaceous marie, is interposed at
the junction, which may seem to
countenance this idea, — that where
the series of deposits was permitted,
from the circumstances under which
they have been formed, to proceed
quietly, such a gradation may have
taken place." — fConyleare.j The
greatest thickness of the chalk strata
in England may be estimated at
from 600 to 1,000 feet. The organic
remains in the chalk formation are
exclusively marine. The nodules
and veins of flint which occur in
the chalk, show that water holding
silex in solution must have been
very abundant at the cretaceous
period, although we are ignorant
by what means silex may be dis-
solved in water. Mammalia are
not known in the cretaceous rocks.
The testacea hitherto obtained from
the various members of the cre-
taceous group amount to about one
thousand. The plants found in
the chalk of England and Prance
are principally marine. Sulphuret
of iron is the only metallic sub-
stance, or metalliferous ore, found
in either the upper or lower chalk.
The chalk hills of England are
bounded by a line which stretches
from south-west to north-east, and
they form three principal mountain
ranges. The first, leaving Berk-
shire, runs north through Bucks,
Bedfordshire, and Hertfordshire, to
Gogmagog hills, near Cambridge.
The second, passing from Berkshire
eastward, stretches through Surrey,
where it forms the Hog's Back, a
beautiful ridge extending from
Farnham to Guildford, and then
appears at Boxhill. This branch
forms the hilly country and the
Downs north of Reigate, Bletch-
ingly, and Godstone. It enters
Kent to the north of "Westerham,
and extends to Folkstone and Dover.
One division of this ridge is con-
tinued to the north coast of Kent,
and terminates at the North Fore-

C H A

[83]

C H A

land. The third range, leaving
Wilts and Berks, enters Hants,
and to the south passes round
Petersfield, then, stretching to the
east, forms a barrier against the
sea along the coast from Chiehester,
constituting the South Downs,
ranging from Mapledurham to
Beachy-head. For a description of
the organic remains of the chalk
formation, the reader is referred to
the article Cretaceous group.
CHALK MARL. (Craie Tufau, Fr.
Kreide mergel, Germ.) The beds
of chalk marl, says Mr. Conybeare,
which occur immediately beneath
the chalk, graduate into the lowest
strata of that subtance, in such a
manner that very often no distinct
line of separation can be traced.
On the other hand, the lowest beds
of the chalk marl often pass into
those of the green sand, and it is
sometimes difficult to catch any
precise characters for a formation
which is thus rather intermediate
between two others, than possessed
of independent features. The com-
position of these beds consist appar-
ently of three ingredients, intimately
blended, but in various proportions;
cretaceous matter ; argillaceous
matter; and sand. In the upper
beds, the cretaceous matter is the
most abundant ; and these commonly
have the appearance of chalky beds,
but distinguishable from the true
chalk by a mottled or greyish
character, by a more laminated
texture, and by falling to pieces
when dried, after having been
wetted. When the argillaceous
matter greatly prevails, a tenacious
bluish-grey marl is the result.
When the sand prevails, a fine-
grained grey-coloured sandstone,
having a loose texture, is produced;
and this last is found graduating
into the green sand. The chalk
marls attain a thickness, in some
situations, of from 300 to 500 feet.
The inclination of the strata is

conformable to that of the super-
jacent chalk, being usually nearly
horizontal, but where, as in some
situations, the chalk has been tilted
up, as in the Isles of Wight and
Purbeck, there also will the chalk
marl be found in conformable posi-
tion. The chalk marl has been
called by some authors grey marl.
For further particulars see Grey marl.

CHA'LICO-THEBIUM. An extinct animal,
belonging to the order of Mammalia,
allied to the tapir, and referrible to
the miocene period.

CHAMA. (Animal a chiton.) A genus
of inequivalved adhering bivalves,
with unequal incurvated beaks.
It is placed both by De Blain-
ville and Lamarck in the family
ChamaceaB, together with Diceras,
Etheria, &c. Bruguiere limits this
genus to those shells possessing a
single hinge-tooth only. Many
species have been found fossil,
more particularly in the neighbour-
hood of Paris. The shells of this
genus are inhabitants of the ocean,
and live in deep water. Twenty-
five species have been described;
one only of these has been dis-
covered in our seas, namely, the
Chama Cor.

CHAMA'CEJE. A family of bivalves
placed by Lamarck in the order
Dimyaria, and by De Blainville in
the order Lamelli-branchiata. It
comprises the genera chama, diceras,
etheria, isocardium, trigonia, &c.

CHA'MA GIGAS. (The Tridacna of
Lamarck.) A species of chama
inhabiting the Indian ocean ; it is
the largest and heaviest shell yet
discovered, being sometimes of the
enormous weight of 530 pounds,
and its occupant so large as to
furnish one hundred and twenty
men with a meal ; it is said to be
very palatable. Fossil shells of
the chama gigas are collected by
the inhabitants of the East Indian
archipelago, for the purpose of being
formed into armlets and bracelets.

C H A

[84]

CHE

CHA'MBEEED. (chamlre, Fr.) Divided
into compartments by septa: the
chambered shells have also been
called multilocular. The fossil
chambered shells are exceedingly
numerous, and afford proofs of not
only having performed the office of
ordinary shells, as a defence for the
oody of their inhabitants, but also,
of having been hydraulic instru-
ments of nice operation and delicate
adjustment, constructed to act in
subordination to those universal
and unchanging laws, which appear
to have ever regulated the move-
ments of fluids. The history of
chambered shells illustrates also
some of those phenomena of fossil
conchology, which relate to the
limitation of species to particular
geological formations; and affords
striking proofs of the curious fact,
that many genera, and even whole
families, have been called into
existence, and again totally anni-
hilated, at various and successive
periods, during the progress of the
construction of the crust of our
globe.— Prof. BucUand.

CHAMITE. The fossil shell of the
genus chama. The Hon. Mr.
Strangways, in his description of
the Geology of the environs of
St. Petersburg, says, " There occurs
a bed of yellowish-white sand con-
taining organic remains. These
are only one large species of chamtte,
in very good preservation, usually
of a brownish colour and retaining
the original polish of the shell.
The two beds immediately above
this consist also of a sandstone
containing chamites. The lowest
is usually of a reddish or even rosy
colour, and contains vast quantities
of chamites, or rather fragments of
them, strewed throughout its mass,
in the direction of the planes of
stratification. The upper bed is
^ equally filled with chamites, some
of which have a tendency to
iridescence or metallic lustre. Cha-

mites are found in the supracre-
taceous deposits, in the cretaceous
group, and in the oolite formation.
CHAEA. A genus of aquatic plants
found both recent and fossil. Fossil
chara3 occur in formations of differ-
ent eras. Charae are often of con-
siderable importance to the geologist
in characterizing entire groups of
strata. The seed-vessel of these
plants, says Sir C. Lyell, is re-
markably tough and hard, and
consists of a membranous nut
covered by an integument, both of
which are spirally striated or ribbed.
The integument is composed of five
spiral valves, of a quadrangular
form. The stems of charse are
found fossil in great abundance in
the Scotch marl or travertin, they
are striated, and while the striae of

. the stems turn, like the worm of a
screw, from right to left, those of
the seed-vessel wind from left to
right. "When first these seed-
vessels were discovered, in a fossil
state, they were supposed to be the
shells of an unknown species of
mollusk, and a genus was formed
for their reception, and termed
gyrogonites, or twisted stones, a
name by which they are still often
designated.

CHA'EACEJE. In the vegetable king-
dom, the fourth order of Thalogens,
comprising the chara, &c.

CHARA HISPIDA. A species of the
genus chara, above described. The

. stems of this species are longitudi-
nally striated, possessing at the same
time a disposition to spirality. In
this, and other, species of chara,
the living plant contains so large a
portion of carbonate of lime in its
structure, that when dried it effer-
vesces strongly with acids.

CHATOYANT. | (Fr .Ilseditd'unobjet

CHATOYANTE. j dont la couleur varie,
suivant la direction de la lumiere,
qui le frappe.) A term used to
signify that changeable play of
light observable in certain minerals,

CHE

[85]

CHE

as in moonstone and chrysoberyl,
the opal, labradorite, &c., &c.

CHEIRAC'ANTHTJS. (from xe^> the
hand, and atcavOa, a thorn or spine,
Gr.) The name assigned to a
genus of ichthyolites found in the
lower old red sandstone. The
cheiraeanthus, says Hugh Miller,
must have been an eminently
handsome little fish, slim, tapering,
and described in all its outlines,
whether of the body or the fins,
by gracefully-waved lines. The
body was covered with small angular
scales, brightly enamelled, and
delicately fretted into parallel ridges
that run longitudinally along the
upper half of the scale, and leave
the posterior portion of it a glitter-
ing smooth surface. The tail had
the unequal-sided character common
to the formation. There is a single
dorsal fin placed about two thirds
down the back. But it is rather in
the construction of the fins than
from their position, that the pecu-
liarities of the cheiraeanthus are
most marked. The anterior edge
of each, as in the pectorals of the
existing genera Cestracion and
Chimera, is formed of a strong
large spine. In the Cheiraeanthus,
each fin seems to consist of but a
single spine, with an angular
membrane fixed to it by one of its
sides, and attached to the creature's
body on the other. Its fins are
masts and sails, the spine repre-
senting the mast, and the membrane
the sail ; and it is a curious char-
acteristic of the order, that the
membrane, like the body of the
ichthyolite, is thickly covered with
minute scales.

CHEIROLE'PIS. (from %«/>, a hand or
fin, and XeWs, a scale, Gr.) A
genus of ichthyolites of the old red
sandstone. In this genus we find
a union of the cartilaginous with
the osseous skeleton. The external
skull, the great shoulder-bone, and
the rays of the fins, are all un-

equivocally osseous, while the
internal skeleton is cartilaginous.
The cheirolepis is found from four
to fourteen inches in length. Five
species have been enumerated. —
Hugh Miller.

CHEIRO'PTER. (from xe'P> a band, and
Trrepbv, a wing, Gr.) An animal
having the fingers elongated, for the
expansion of membranes which act a
wings, as in the Yespertilio or bat.
The Cheiroptera form the tenth
order of mammalia, which is sub-
divided into Ch. Frugivora, and
Ch. Insectivora.

CHEIRO'PTEROITS. Furnished with
elongated fingers, or toes, for the
expansion of membranes which
serve as wings; belonging to the
family Cheiroptera.

CHELI'FEROTJS. (from x1?^ ^r- a
claw, and fero, Lat.) Furnished
with claws ; armed with claws .

CHELO'NIA. (from '^eKiavrj, testudo.)
The tortoise tribe. Chelonia, the
first order of Reptilia, is divided
into four families, namely, land
tortoises, testudo; pond tortoises,
emys ; river tortoises, trionyx ; and
sea tortoises, or turtles, chelonia.

CHE'LONICTHYS. The name assigned
by Agassiz, in the first instance, to
an ichthyolite of old red sandstone ;
this name has subsequently given
place to Asterolepis.

CHE'LONITE. A name given to some
fossil echinites, from their resem-
blance, in their sutures, to the shells
of the tortoise. The chelonite
belongs to the family Cidaris, class
Anocysti.

CHELY'OPHORTJS. A genus of icthyo-
lites of the old red sandstone,
described by Agassiz in his Poissons
Fossiles.

CHOSROPO'TAMTTS. } An extinct genus

CHEROPO'TAMTJS. j in the order Pac-
hydermata, or animals having thick
skins. The cheropotamus was an
animal most nearly allied to the
hog ; forming a link between the

CHI

L 86 J

C H I

Anoplotherium and the Peccaryv —
Bucldand.

The remains of the cheropota-
mus have been found in the
gypsum of Paris, and in the eocene
limestone of the Isle of Wight.
From an examination of these,
Cuvier considered that this genus
more nearly approximated to the
genus porous than the anoplo-
therium or palseotherium, and yet
did not resemble the living swine.
In no other part of Great Britain
but in the Isle of Wight, has any
portion of the cheropotamus been
found.

CHEST. (Dr. Johnson deduces chert
from quartz.) A variety of horn-
stone. Chert is also, by some,
called horn-stone. A siliceous stone,
resembling flint, but less splintery
in the fracture, and fusible ; which
latter property is probably owing
to some admixture of calcareous
matter. A gradual passage from
chert to limestone is not uncommon.
Although the words flint and chert
are frequently used indiscriminate-
ly, they are not to be regarded as
synonymous. Chert is not gene-
rally to be found in distinct
globular masses as flint is, but
rather in continuous layers, sepa-
rating thicker strata of rocks.

CHIA'STOLITE. (from ^taa^, decussa-
tionis for mam halens, and X/009.)
A mineral whose crystals are
arranged in four-sided nearly rec-
tangular prisms, presenting a black
cross in their transverse section :
it has obtained its name from being
marked with the form of an X, in
dark lines, visible on the summits
of the crystals. Its constituent
parts are, silica 60-49, alumina
30-17, magnesia 4-12, oxide of
iron 2-7, water 0.27. It is the
Holspath of Werner, and the Made
of Haiiy. It is found in Cumber-
land and Argyleshire, occurring in
clay-slate.

CHIASTOLI'TIC. Composed of chias-
tolitej containing chiastolite. A
mass of chiastolitic and hornblendic
slates forms the base of the clay-
slate system of Cumberland.
CHILA'GNATHA. An order of the class

Myriapoda, which see.
CHILO'PODA. An order of the class
Myriapoda, the centipede is an
example.

CHIM^'EA. (from x^/>«, Or.) A
genus of animals, placed in Cuvier's
arrangement in the order Sturiones,
or Chondropterygii Branchiis Libe-
ris, class Pisces. Professor Buck-
land observes, " The Chimaera is
one of the most remarkable among
living fishes, as a link in the
family of Chondropterygians ; and
the discovery of a similar link, in
the geological epochs of the oolitic
and cretaceous formations, shows
that the duration of this curious
genus has extended through a
greater range of geological epochs,
than that of any other genus of
fishes yet ascertained by Professor
Agassiz. The jaws of four extinct
species of fossil fishes of the genus
Chimeera have been discovered, and
Dr. Mantell states that the jaw,
or mandible, of a Chimera, has been
found in the Kentish Eag. The
only known species is the Chimsera
monstrosa, or Arctic chimera, two
or three feet in length, of a silvery
colour, and spotted with brown.
This species has the first ray of the
dorsal fin enlarged into a strong
bony spine, armed with sharp hooks,
and placed over the pectorals ; like
the Icthyodorulite of the earliest
fossil sharks. ' It produces large
coriaceous eggs with flattened and
hairy borders.

CHINA CLAY. Called also porcelain
earth. The name given to disin-
tegrated protogine ; decomposed
granite. A clay found in some
parts of Cornwall, in pits of the
depth, sometimes, of twenty feet.
This clay when first raised from

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the pits has the appearance and
consistence of mortar : it contains
numerous grains of quartz, which
are disseminated through it in the
same manner as in granite. In some
parts the clay is stained of a rusty
colour, from the presence of veins,
and imhedded portions of shorl
and quartz. By a process of
washing and mixing with water,
the china clay is freed from all
extraneous matters, and is then
allowed to subside ; it is afterwards
cut into pieces, thoroughly dried,
packed in casks, and shipped for
the potteries. The quantity ex-
ported from Cornwall exceeds 7,000
tons a-year. China clay contains
no alkali and is consequently wholly
without felspar.

CHINA STONE." A kind of granite,
(containing talc, hut wholly desti-
tute of mica), the felspar of which
has undergone a partial decompo-
sition. It has obtained its name
from being employed in the
manufacture of English china.
Many thousand tons are annually
shipped from Cornwall for the
potteries.

CHINE. A narrow ravine with
vertical sides. These are numerous
in the Isle of "Wight, and are
objects of curiosity and admiration,
being sometimes of great depth.
The word chine appears to be
synonymous with^w%. In Hamp-
shire, and in the Isle of Wight,
the chasms through which the
rivulets empty themselves into the
sea, are commonly termed chines ;
thus we have Shanklin Chine,
Blackgang Chine, &c.

CHIBOTHE'BTUM. A name proposed to
be given by Professor Kaup to the
great unknown animal whose
footsteps have been discovered in
beds of red sandstone. These
footsteps are beautifully figured in
Professor Buckland's Bridgewater
Treatise. The name proposed by
Kaup is on account of a distant

resemblance, both of the fore and
hind feet, to the impression of a
human hand.

These impressions of feet are
partly hollow, and partly in relief ;
all the depressions are upon the
upper surfaces of slabs or sand-
stone, while the reliefs are only
upon the lower surfaces, covering
those which bear the depressions.
These footsteps follow one another
in pairs, at intervals of fourteen
inches, from pair to pair, each pair
being in the same line. Both large
and small steps, have the great- toes
alternately on the left and right
side; each has the print of five
toes, and the first, or great-toe, is
bent inwards like a thumb. The
fore and hind foot resemble each
other in form, though they differ
greatly in size.

CHI'TON. (from xi™v, Gr.) An
oval convex, multivalved shell,
having eight arcuated valves, partly
lying over each other in a row
across the back of the animal. The
chiton is found both fossil and recent;
recent, attached to rocks in the
southern seas; fossil, at Grignon.
The animal inhabiting the shell, a
Doris. In Turton's Linne, twenty-
eight species of chitons are de-
scribed, seven of which have been
found in the seas of our coasts.

CHLAMI'PHOEUS. (from xXay&vs, and
06/3H?, Gr.) The name it pos-
sesses has been given to this
animal from its being cased in a
coat of armour. The chlamyphorus
and armadillo are the only known
animals that have a compact coat
of plated armour. The chlamy-
phorus lives almost entirely in
burrows beneath the surface of
sandy plains; its scales are of a
dense substance, resembling hard
leather.

CHLOEINE. (from x\ay>o9, green, Gr.)
A yellowish-green coloured gas, of
a pungent smell, and most injurious
to respiration. Chlorine was dis-

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covered by Scheele in 1774. It
is not permanent over water, which
absorbs twice its volume. Specific
gravity 2-47, 100 cubic inches
weighing 75 '67 grains. United
with an equal volume of hydrogen
gas it gives two volumes of hydro-
chloric or muriatic acid. In
nature, chlorine exists most abun-
dantly in chloride of sodium or
common salt. Its equivalent num-
ber is 35-42; its symbol Cl.
Chlorine has never been decomposed.

CHLO'RITE (from %Aw/>o9, green, Gr.)
A. mineral, consisting of silica,
27-43, alumina 17-9, lime 0-50,
oxide of iron 30-63, magnesia
14'56, potash 1-56, water 6*92.
It is a dark green variety of talc ;
has a glistening lustre; minutely
foliated structure ; is soft and
unctuous to the feel; and has
obtained its name from its colour.
There are several varieties of talc
having a dark green colour, and
these are known as compact chlorite,
earthy chlorite, chlorite slate, foli-
ated chlorite, &c. Chlorite and
talc pass by insensible gradations
into each other, and in this state
they supply the place of mica, in
most of the granitic rocks in the
vicinity of Mont Blanc.

CHLORITE ROCK. A name proposed,
by Dr. Boase, to be given to a
genus of rocks found in Cornwall.
The term is synonymous with
Chlorolite, which see.

CHLO'RITE-SCHIST. A metamorphic
rock, of a green slaty character,
abounding with chlorite.

CHLORI'TIC - SAND. Sand coloured
green by an admixture of chlorite.
— Lyell.

CHLOBI'TIC GRANITE. Granite con-
taining particles of chlorite.

CHLOROLITE. (from %Xto/>o9, green,
and X$os, a stone, Gr.) A com-
pound of granular compact-felspar
and a mineral resembling chlorite.
Three species are enumerated by
Dr. Boase, namely, compact, lamel-

lar, and schistose chlorolite. Chlo-
rolite abounds in quartz veins
containing compact and crystalline
chlorite, and which are often very
rich in metallic minerals, particu-
larly in copper ores. Chlorolite is
found in Cornwall and is a primary
rock.

CHLOROPHGEITE. A mineral discover-
ed by Dr. Me Culloch. It was
found imbedded in the amydaloids
of the cliffs of Scuirmore in the
Isle of Rum, and has since been
brought from Iceland.

CHCEROPOTAMUS. j The name assigned

CHEROPOTAMUS. ) by Cuvier to a
genus of fossil quadrupeds of the
hog tribe, the earliest, according to
Professor Owen, of this tribe intro-
duced upon our planet. This qua-
druped, says Owen, must have
resembled the Peccari, but was
about one- third larger. The only
locality in Great Britain where any
portion of the Chceropotamus has
been discovered is in the Isle of
Wight, in the eocene limestone, a
locality corresponding with the
Paris basin in mineral character, as
well as in date of origin.

CHO'ANITE. A zoophyte of the chalk
formation, intermediate between
Alcyonia and Yentriculites. Dr.
Mantell, in his "4 Wonders of
Geology," states, " the choanite,
called petrified sea-anemone by
lapidaries, bears a close resemblance
to the recent Alcyonia. In the
choanite, crucial spines, resembling
those in the recent Alcyonia, may
be detected. The choanite is of a
sub-cylindrical form, with root- like
processes, and having a cavity or
sac, which is deep and small in
comparison to the bulk of the
animal The inner surface is stud-
ded with pores, which are the
terminal openings of tubes, disposed
in a radiating manner, and ramify-
ing through the mass." The beau-
tiful pebbles found on the shores
of Bognor and Worthing owe their

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CHE

markings to the internal structure
of the choanite, and these are
worked into a variety of ornaments,
as brooches, buckles, earrings, &c.

CHOKE-DAMP. A name given by
miners to carbonic acid.

CHO'NDRODITE. Hemiprismatic chry-
solite. Another name for brucite ;
a mineral composed of magnesia
54, silica 32, fluoric acid 4, oxide
of iron 2, potass 1, and water 1.

CHONDROPTER'YGII. One of the two
great divisions in the classification
of fishes, comprising all the cartila-
ginous genera. The cartilaginous
fishes — Chondropterygii of Cuvier.
— Hugh Miller.

CHONDROPTER'YGIAN. Belonging to
the division of fishes named Chon-
dropterygii.

The cartilaginous or chondroptery-
gian fishes. The long-fronted
chondropterygian series of Cuvier.
— Hugh Miller.

CHROMATE. A mineral containing
chromic acid with a base, as chro-
mate of lead.

CHRI'STTANITE. An earthy mineral
so named by Monticelli, after
Prince Christian of Denmark. See
A.northite.

CHROME. | (from x/V*^a> colour,

CnRo'MruM. j Gr.) This mineral
is said to have obtained its name
from the property it possesses of
imparting colour to other bodies in
a very remarkable degree. Chro-
mium was first discovered by
Vauquelin in 1797, after a variety
of discordant analyses made by
Macquart, Bindheim, and others.
Specific gravity about 5-0. Its
principal ore is found in Siberia,
and is a salt of lead, formed by an
acid oxide of chromium. To the
presence of chrome the emerald
and the ruby owe their hues. It
is used in tinting glass of an
emerald green.

CHRYSOBE'RYL. (from x/>v<ros, gold,
and prjpvKkiov, gemma.) The
cymophane of Haiiy. Chrysopal of

Delametherie. Werner first made
the chrysoberyl a distinct species,
and gave it the name which it now
bears. Colour, a light yellowish or
asparagus green. This gem is
found in the Brazils, in Ceylon, in
America, and in Siberia. It occurs
in the alluvial deposits of rivers,
and consequently in rolled and
frequently much worn masses;
also chrystallized. It consists of
alumina 76 -75, glucina 17- 79, and
protoxide of iron 4*50, — according
to Thomson; Klaproth's analysis
gives alumina 71*5, lime 6*0,
silica 18'0, oxide of iron 1*5.
Its specific gravity 3 '6 to 3 -8,
hardness = 8 '5. " The primary
form of its crystal is a right rec-
tangular prism. By friction it
becomes electric. Alone it is
infusible before the blow-pipe, but
with borax it melts slowly, forming
a transparent glass. It displays a
beautifully changeable play of
light. When free from flaws it is
a handsome gem, but not of the
first order in value.
CHRY'SOLITE. (from x/avo-o? gold,
and A/005, a stone, chrysolite, Fr.)
The Peridot of Haiiy, and Kriso-
lith and Olivin of Werner. The
term chrysolite was applied, with-
out any regard to distinction,
or any discrimination, to a great
variety of precious stones, till
Werner defined it accurately, and
confined it to that stone which the
French mineralogists distinguish by
the appellation of Peridot (sorte de
pierre precieuse, peu recherchee,
qui tire un peu sur le vert.) Chry-
solite contains a very large pro-
portion of magnesia, according to
some authorities more than half its
weight, but agreeably to the ana-
lysis of others from forty to fifty
per cent. Chrysolite is of a green
colour, inclining to yellow; its
texture is foliated; fracture con-
choidal. It causes double refrac-
tion. It is infusible at 150°, but

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C I M

at that temperature loses its trans-
parency, and becomes of a dark
grey. With borax it melts, with-
out effervescence, into a transparent
glass of a light green colour. The
chrysolites of commerce come from
Upper Egypt and the Brazils; they
are also found in Ceylon, in South
America, and in Bohemia. The
variety called Olivine is met with
in Scotland ; of this the colour is
olive-green. According to the
analysis of Klaproth, chrysolite
consists of magnesia 43, silica 38,
oxide of iron 19.

CHRY'SOPRASE. (from x/>v<ro9, gold,
and prasinm, green; chrysoprase,
Fr. Pierre precieuse d'un vert clair
meU d'une nuance de jaune.J A
precious stone of an apple-green
colour. It is a variety or sub-
species of calcedony. It owes its
colour to the presence of the metals
nickel and iron, in small quantities.
It is found in different parts of
Germany, particularly in Silesia.
It is always amorphous, and posses-
ses but little lustre. It consists of 9 6
per cent, silica, 1 per cent, oxide
of nickel, with a trace of iron,
alumina, lime, and magnesia.

CHTJSITE. A mineral discovered by
Saussure in the cavities of porphy-
ritic rocks near Limbourg, and in
Switzerland.

CICATRICE. ] (cicatrix, Lat. cicatrix,

CI'CATRIX. j Fr. cicatrice, It.

1. The scar remaining after a wound.

2. In conchology, the glossy im-
pression in the inside of the valves,
to which the muscles of the animal
have been affixed.

CI'DARIS. (cidaris, Lat.) A family
of echinites, characterized by being
hemispherical, globular, or sub-
oval ; with porous ambulacra, di-
verging equally on all sides, from
the vent to the mouth ; vent
vertical ; mouth beneath, and
central. The name cidaris has
been given to them from their
supposed resemblance to turbans.

From other characters, derived
from their spines, they have ob-
tained the names of sea-urchins,
sea-hedgehogs, sea- thistles, &c.,
and those in a petrified state have
obtained various names, according
to the particular, fanciful, and
erroneous notions which have been
entertained respecting their origin.
Thus, they were called ombria,
from ojappos, Gr. signifying the
heavy rain, in which it was sup-
posed they fell ; brontia, from
fipovrjj, from an idea that they
were thrown to the earth by
thunder; ceraunii lapides, from
Kepawos, under an impression that
they were formed in the air and
generated by lightning ; chelonites,
from their resemblance to the shells
of the tortoise; and ova anguina,
from their being supposed to be the
eggs of serpents. — Parkinson.

The species are numerous; eigh-
teen species are described as occur-
ring in the oolite, and nine in the
chalk formation.
CI'LIA. (from cilium, Lat.)

1. The eye-lash.

2. Hair-like vibratile organs. The
organs of motion in the radiated
animals. The cilia resemble very
minute hairs, and are only visible
with the microscope. In the
simpler forms of animals, the cilia
are the organs for motion, respira-
tion, and the obtaining of food.
Dr. Grant has calculated four
hundred millions of them on a
single flustra foliacea.

CI'LIATED. Fringed, or edged, with
parallel hair, bristles, or appen-
dages; occupied with short stiff
hairs.

CTMOLIO'RNIS. (from KipwXia, chalk,
and opvi9, a bird, Gr.) The name
assigned to a fossil bird found in
the chalk formation.

CIMOLITE. (So named from its
abounding in the island of Cimolia,
now called Argentiera, in the
Mediterranean.) A clay of a light

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greyish- white, which, by exposure
to the air, becomes of a reddish
colour. It occurs massive, and
exhibits a somewhat slaty texture.
It consists of silex 63, alumine 23,
water 12, aad oxide of iron 1-25.
It was highly prized as a medicine
by the ancients. It is opaque,
dull, and has an earthy fracture.
Though somewhat difficult to break,
it receives an impression from the
nail. It adheres to the tongue.
Specific gravity 2.

CfNNABAE. (from Kiwafiapt, Gr.
cinabre, Er. cindbro. It.) The
mercure sulphure of Haiiy. Native
cinnabar is a red, heavy, sulphureous
ore of quicksilver, the principal
mines of which are at Idria in
Carinthia, and at Almaden in Spain.
Cinnabar is called "ore of mercury,"
since from it mercury is obtained.
Before the blow-pipe, it is infusible
without addition, but loses its color,
and becomes opaque. Specific gra-
vity from 2-60 to 3 25.

CI'NNAMON-STONE. (The Kanelstein,
or Kaneelstein, of Werner; Hiacint
of Mohs ; Essonite of Haiiy.) So
named from the resemblance of its
colour to that of cinnamon. Cinna-
mon-stone has been hitherto found
in masses only, full of fissures, and
in grains in the mud of rivers. It
is transparent, or only translucent ;
scratches quartz with difficulty.
Fracture imperfectly conchoidal,
with small cavities, and shining.
Specific gravity 3*60. Before the
blow-pipe, it fuses into a brownish-
black enamel. When cut, it has
rather a greasy feel. The Roman-
zovite of Nordenskiold is considered
to be a variety of cinnamon-stone.
A blood-red, or hyacinth-red, variety
of the dodecahedral garnet. It
consists of silica, alumina, lime,
and oxide of iron. The finest
specimens are brought from Ceylon,
where it is found in the sand of the
rivers. It is also called Essonite.

CIPOLI'NO. A granular limestone,
containing mica,

CI'EEHOPOD. (from cirrus, Lat. and
TOUS, Gr.) The cirrhopods, or
cirrhopoda, like theentomostraceous
Crustacea, are articulated animals,
enclosed in shells like those of
mollusca, so that they present both
forms of the skeleton. The cirr-
hopods are almost always enclosed
in multivalve shells, secreted from
the outer surface of a fleshy, thin,
enveloping, mantle, and are attached
to submarine bodies either directly,
by their base, or by means of a
fleshy tubular peduncle. The bar-
nacle is an example of the cirr-
hopoda. In Cuvier's arrangement
the cirrhopoda form the sixth class
of Mollusca. Linnseus comprised
them all in one genus, Lepas; they
have since been divided into two,
and again, by others, subdivided.
Prof. Grant places the cirrhopoda
in the sub-kingdom diplo-neura or
helminthoida. He thus describes
them, " aquatic, sub-articulated,
diploneurose animals, with nu-
merous lateral articulated cirrhi,
distinct branchiaB for respiration, a
pulsating dorsal vessel for circula-
tion, body covered with a fleshy
mantle and fixed inverted in a
sessile or pedunculated multivalve
shell."

C'EEIPEDE. An annulose, articulated,
animal without jointed feet. Cirr-
ipedes are found only in the upper
secondary, and in tertiary deposits.

CIEEIPED'IA. The sixth order of the
class Crustacea.

CI'REUS. (cirrus, Lat.) A genus
of fossil spiral shells of the chalk
deposit. This genus bears great
resemblance to trochus, from which,
however, it may be distinguished
by its deep funnel-shaped umbilicus.

CLADO'DUS. The name assigned by
Agassiz to an ichthyolite of the
old red sandstone formation.

CLATHEA'EIA LYE'LLII. (described in
the Geological Transactions as
Clathraria anomala.) A fossil
plant discovered by Dr. ManteM,
and thus named by him in honour

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of Sir Charles Lyell. The follow-
ing description is extracted from
Dr. MantelTs works. The Cla-
thraria Lyellii bears an analogy to
the yucca, and dracsena or dragon-
blood plant. Stems, with the
markings of the bases of the
leaves, point out the relation of
this vegetable to the arborescent
ferns, while its internal structure
is essentially different. The cla-
thraria has only been found in the
quarries in Tilgate Forest. This
vegetable appears to have possessed
a thick epidermis, or false bark,
formed by the union of the bases
of the leaves, and covered external-
ly with distinct rhomboidal scales,
each scale being surrounded by an
elevated ridge. The form of the
leaves is not positively known,
although, from some imperfect
traces on the stone in a specimen
bearing the impressions of the
cicatrices of the bases of the leaves,
there is reason to conclude that
they were of a lineari-lance olate
form. The axis, or interior part
of the trunk, originally enclosed by
the bark, occurs in the state of
solid subcylindrical blocks of sand-
stone, attenuated at their base, the
surfaces of which are marked with
longitudinal interrupted ridges, and,
in some instances, are deeply
imbricated ; they are generally of
a dark-brown colour.

CLAVAGE'LLA. A genus of bivalves,
of which only one species has been
found recent, in the Sicilian seas.
It has two irregular, flattish valves,
one of which is clasped by the
tube, the other being left free.
Mr. Sowerby observes, " The shells
composing this genus are found in
stones, madrepores, &c. and appear
to form the connecting link between
Aspergillum, which has both valves
cemented into the tube, and Fistu-
lana, which has both free."

CLA'VICLE. (clavicula, Lat. clavicule,
"Fr. clavicula, It.) The collar-bone.

CLAY. When clay is quite pure and
unmixed (and in this state it is one
of the rarest substances in the
mineral kingdom) it is termed
alumina, but under the term clay
is comprehended an«€xtensive class
of compounds, of which silex is a
principal constituent. Clay, then,
may be defined an unctuous and
tenacious earth, capable of being
moulded into form ; any earth
which possesses sufficient ductility,
when kneaded with water, to be
fashioned like paste, by the hand,
or by the potter's lathe. Clays
are firmly coherent, weighty, com-
pact, and hard when dry, but stiff,
viscid, and ductile when moist ;
being smooth also and unctuous to
the touch. Besides alumina and
silica, clays often contain carbonate
of lime, magnesia, barytes, oxide
of iron, &c. When clay is breathed
on, it yields a peculiar smell ; it
has also a strong affinity for
moisture, which is shown by its
sticking to the tongue, when ap-
plied to it. The purest clay is
kaolin, or porcelain clay. All clays
appear to be mechanical deposits,
not one of them occurring crystal-
lized, or with a crystalline structure;
some are found slaty.

CLAY-SLATE. (The argillite of Kir-
wan.) An indurated clay or shale,
common to the fossiliferous and
metamorphic series. Clay-slate is
opaque, of various shades of colour,
and of different degress of hardness,
but easily scratched by iron. It is
composed of about fifty per cent.
of silex, twenty-five of alumine,
and ten or twelve of oxide of iron.
Some varieties are used as whet-
stones. The common hone is a
variety of slate containing a smaller
proportion of alumine and some
lime.

CLA'YSTONE. An earthy stone re-
sembling indurated clay, and gene-
rally of a colour approaching to
purple ; it is a variety of prismatic
felspar.

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CLEA'VAGE. A peculiar fracture, im-
pressed by nature, which is some-
times mistaken for stratification.
This is prettily described by Dr.
Mantell : " If I take a flint and
break it at random, it still preserves
a conchoidal fracture, a sharp
cutting edge ; and sub-divide it as
I may, it still retains the same
character. If I shiver to pieces
calcareous spar, every fragment
presents, more or less distinctly, a
rhomboidal form ; so true is the
remark, that we cannot break a
stone but in one of nature's join-
ings."

The regular partings or cleavages
in many slate rocks which inter-
sect the beds, nearly at right
angles to their dip or inclination,
have often been mistaken for strata
seams, and have led geologists of
some eminence to draw very er-
roneous conclusions.

"Cleavage means the superin-
duced fissile structure of clay-
slate ; cleavage pays no regard to
the laminae of deposition, or original
bedding of the rock, but frequent-
ly cuts right across it." — Jukes.

"Where only part of a bed is
exposed, it is often difficult to
distinguish the lines of cleavage
from the true planes of stratification;
but the doubt may be cleared by
observing the upper and under
surface of the bed at the line of its
junction with its superstratum and
substratum, especially if these be
of a different substance. — Conyleare
and Phillips.

CLEAE'VLANDITE. A mineral, to which
this name has been given after
Professor Cleaveland ; it has been
also called albite.

CLIMATIFS BETICULATTJS. An ichthy-
olite of the old red sandstone, de-
scribed by Agassiz in his Poissons

CLI'NKSTONE. (So named from its
yielding a metallic sound when
struck.) Called also phonolite, a
felspathic rock of the trap family.

In basalt or wacke*, when the
felspar greatly prevails, and the
texture becomes nearly compact,
basalt passes into clinkstone ; again,
when clinkstone has a more earthy
texture, it passes into claystone.
Clinkstone often contains imbedded
crystals of felspar, and then be-
comes a trap-porphyry, varying in
colour according to the prevailing
ingredients of its base. The colour
of clinkstone is grey, of various
shades. According to Gmelin,
natron and potash characterize
clinkstone; iron and magnesia,
basalt.

CLINO'METER. (from K\IVW and juterpov,
Gr.) An instrument, invented by
R. Griffith, Esq., for measuring
the dip of mineral strata. The
following description of the clino-
meter is extracted from a paper by
Lord Webb Seymour, presented to
the Geological Society. The clino-
meter consists of two parts, the
plate and the quadrant. The plate
is circular and of brass ; it is sup-
ported by three feet placed at
equal distances, and made of wood,
with their ends flat and broad.
The clinometer may be used to
determine the position of any plane
surface to which the plate may be
applied so as to admit of obser-
vation with the quadrant.

CLO'VATE. In conchology, thicker
towards the top, elongated towards
the base.

CLO'VEN. In botany, leaves are called
cloven, when the margins of the
segments and fissures are straight.

CLTJNCH. A provincial term for a
sort of indurated clay which is
found dividing the coal seams.
The clunch yields those infusible
kinds of clay which are adapted for
fire-bricks ; it varies in hardness,
and is black, grey, yellow, white,
&c. In the coal series it is gene-
rally found immediately beneath
each bed of coal, and where it
crops out at the surface becomes
soft clay.

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CLYME'NIA. A genus of Ammonites
established by Count Munster, (the
Endosiphonites of Ansted) distin-
guished by having the siphon
placed on the ventral margin or
close to the body whorls. Morris's
catalogue records seven English
species from the Devonian system
in Cornwall. — Lycett.

CLT'PEIFOEM. Of a shield — like shape
or form.

CLY'PEUS. (Lat.) A division of the
first class of echinites. The fossil
echinites of the second division of
anocysti are distinguished as clypei,
from their similitude in form to
the round bucklers of the ancient
foot-soldiers.

COAL. (col, Sax. kol, Germ, hole,
Dutch.) A substance of vegetable
origin, composed of charcoal, bitu-
men, and earthy matter; the
latter forms the ashes which
remain after combustion. Common
coal is a black, solid, and compact
substance, generally of a foliated,
or rather laminated, structure,
whichjiecessarily directs its frac-
ture. Its specific gravity is
1-25 to 1-37. It cakes into
cinders during combustion in pro-
portion to its degree of purity, and
the nature of the earths which
enter into its composition. Coal
has obtained various names from
varieties of appearance, hardness,
situation whence obtained, &c., &c.
The very great improbability of
finding good coal above the chalk
is now acknowledged by all who
have even the smallest acquaintance
with the geological relations of the
English coal mines. The analysis
of coal shews it to consist princi-
pally of carbon, hydrogen, oxygen,
and nitrogen : a specimen of New-
castle coal yielded carbon 75*28,
hydrogen 4-18, oxygen 4*58, ni-
trogen 15-96.

COAL FOEMATION-. The carboniferous
group succeeds the grauwacke in
the ascending series of Europe, and

is so called because the great mass
of European coal is included among
the rocks of which it is composed.
Considered in its greatest gene-
rality? and with reference to where
the masses appear in the greatest
simplicity, the carboniferous sys-
tem consists of three formations,
namely, the coal formation, a mass
1000 yards or more in thickness,
consisting of indefinite alternations
of shales and sandstones of different
kinds, with about fifty feet of coal
in many beds, some ironstone
layers, and (very rarely) thin
layers of limestone ; mountain lime-
stone, a mass of calcareous rocks,
from 500 to 1500 feet in thickness ;
and old red sandstone, a mass of
arenaceous and argillaceous rocks,
varying in thickness from 100 to
10,000 feet. The coal formation
may be understood as applied to
the great and principal formation
of that mineral, interposed between
the newer red or saliferous sand-
stone, and the great carboniferous
limestone and older sandstone for-
mations, or, where these are absent,
resting on transition rocks. This
is the deposit distinguished by the
Wernerians as the independent
coal formation. The total thick-
ness of coal existing in the English
and Scotch fields is generally about
50 or 60 feet, divided into 20 or
more beds, of a thickness of from
six feet to a few inches, alternating
with from twenty to fifty or one
hundred times as great a thickness
of shales and sandstones. Every
coal district has its peculiar
series of strata, unconnected with
any other. A district with its
peculiar series of strata is called a
coal-field. Coal-fields are of limited
extent, and the strata frequently
dip to a common centre, being
often arranged in basin -shaped con-
cavities, which appear to have been
originally detached lakes, that were
gradually filled up- by repeated

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depositions of carbonaceous and
mineral matter. In some of the
larger coal-fields, the original form
of the lake cannot be traced, but
in the smaller ones it is distinctly
preserved. The stratum lying
over a bed of coal is called its roof,
and the stratum under it, the floor.
On the eastern side of England,
the coal strata generally dip to the
south-east point : on the western
side, the strata are more frequently
thrown into different and opposite
directions, by, what are termed,
faults and dykes. A fault is a
break or intersection of strata, by
which they are commonly either
suddenly raised or depressed, so
that in working a coal mine, the
miners come suddenly to its
apparent termination. A dyke is
a wall of mineral matter which,
from igneous or volcanic action, has
been forced upwards through the
strata, cutting them in a direction
nearly vertical. In these cases,
sometimes the coal is reduced to a
cinder for some distance on either
side of the wall or dyke. One of
the green-stone dykes of Ireland,
passing through a bed of coal,
has reduced it to a cinder for the
space of nine feet on each side.
Our ancient coal formation has not
been found in Italy, Spain, Sicily,
or in any of the more southern
countries in Europe. Coal is now
universally admitted to be of
vegetable origin, a question which
was long disputed. It is not
uncommon to find among the
cinders beneath our grates, traces
of fossil plants, whose cavities
having been filled with silt, at the
time of their deposition in the
vegetable mass, that gave origin to
the coal, have left the impression
of their forms upon clay and sand
enclosed within them, sharp as
those received by a cast from the
interior of a mould. Mr. Hutton
has recently discovered the most

decisive and indisputable proof of
the vegetable origin even of the
most bituminous coal ; he has
ascertained that if any of the three
varieties of coal found near New-
castle be cut into very thin slices,
and submitted to the microscope,
more or less of vegetable structure
can be recognised. He says, " each
of these three kinds of coal, beside
the fine distinct reticulation of the
original vegetable texture, exhibits
other cells, which are filled with a
light wine-yellow-coloured matter,
apparently of a bituminous nature,
and which is so volatile as to be
entirely expelled by heat, before
any change is effected in the other
constituents of the coal." The
plants of the carboniferous group
are by no means confined to the
simplest forms of vegetation, as
to cryptogamic plants; but, on
the contrary, belong to all the
leading divisions of the vegetable
kingdom ; some of the more fully
developed forms, both of the di-
cotyledonous and monocotyledo-
nous class, having been already
discovered, in the first three or
four hundred species brought to
light. If violence had attended
the transport of the plants now
converted into coal, or discovered
fossil in the associated beds, the
appearance of those in the latter
would not be as we now find them ;
instead of appearing as if spread
out by the botanist for examination,
we should have had them crushed
and disfigured. Moreover, tran-
quillity seems requisite to explain
the condition of those vertical, or
nearly vertical, stems of plants
discovered in the coal measures of
different situations, where they
have been gradually enveloped by
different beds of sandstone or shale
through which they appear to
pierce. The alternations of lime-
stones containing marine remains,
and of sandstones, shales, and coal-

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beds, with no trace of a marine
auimal in them, are exceedingly
remarkable, and seem difficult of
explanation, without calling in the
aid of oscillations of the solid
surface of the earth, by which very
gradual risings and depressions are
effected.

It is, however, the opinion of
some authors that the alternations
of freshwater shells with marine
remains, do not prove as many
relative changes of sea and land ;
but that the coal-measures were
deposited in an estuary, into which
flowed a considerable river, subject
to occasional freshes; and this
opinion is supported by the fact
of frequent alternations of coarse
sandstones and conglomerates with
beds of clay or shale, containing
the remains of the plants brought
down by the river. The quality
of coal, even in the same district,
very much depends on the nature
of the bed which immediately
covers the coal stratum ; for when
the superincumbent stratum is
sandstone, the coal is greatly dete-
riorated, being, more or less, mixed
with iron pyrites : on the other
hand, if the coal lie immediately
beneath argillaceous shale, its qua-
lity is much better. For economi-
cal purposes, coal may be deemed
more or less valuable, in proportion
to the quantity of bitumen it
contains.

The study of the more ancient
coal deposits has yielded the most
extraordinary evidence of an ex-
tremely hot climate ; for it appears
from the fossils of that period that
the flora consisted almost exclu-
sively of large vascular cryptogamic
plants. M. Ad. Erongniart states
that there existed at that epoch
equiseta upwards of ten feet high,
and from five to six inches in
diameter; tree-ferns, or plants
allied to them, of from forty to
tity feet in height, and arborescent

lycopodiacese, of from sixty to
seventy feet high, exceeding in
their development those now found
in the hottest parts of the globe.
The Newcastle coal-field is supply-
ing rich materials to the fossil
flora of Great Britain. The finest
example of distinctly preserved
vegetable remains is that witnessed
in the coal-mines of Bohemia.
" The most elaborate imitations,"
says Prof. Buckland, "of living
foliage upon the painted ceilings of
Italian palaces, bear no comparison
with the beauteous profusion of
extinct vegetable forms, with
which the galleries of these in-
structive coal-mines are overhung.
The roof is covered as with a
canopy of gorgeous tapestry, en-
riched with festoons of most grace-
ful foliage, flung in wild, irregular
profusion over every portion of its
surface. The spectator feels him-
self transported, as if by enchant-
ment, into the forests of another
world ; he beholds trees, of forms
and characters now unknown upon
the surface of the earth, presented
to his senses almost in the beauty
and vigour of their primeval life ;
their scaly stems, and bending
branches, with their delicate appa-
ratus of foliage, are all spread
forth before him ; little impaired
by the lapse of countless ages, and
bearing faithful records of extinct
systems of vegetation, which
began and terminated in times of
which these relics are the infallible
historians." I can hardly conclude
this article better, than by again
drawing on the composition of the
above quoted elegant and eloquent
author, in transferring to my page
from his delightful work on Geolo-
gy and Mineralogy the following
beautiful passage. " The impor-
tant uses of coal and iron in
administering to the supply of our
daily wants, give to every indi-
vidual amongst us, in almost every

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moment of our lives, a personal
concern in the geological events of
these very distant eras. We are
all brought into immediate con-
nexion with the vegetation that
clothed the ancient earth, before
one-half of its actual surface had
yet been formed. The trees of the
primeval forests have not, like
modern trees, undergone decay,
yielding back their elements to the
soil and atmosphere by which they
had been nourished ; but, treasured
up in subterranean storehouses, have
been transformed into enduring
beds of coal, which, in these later
ages, have become to man the
sources of heat, and light, and
wealth. My fire now burns with
fuel, and my lamp is shining with
the light of gas, derived from coal
which has been buried for countless
ages in the deep and dark recesses
of the earth. We prepare our
food, and maintain our forges and
furnaces, and the power of our
steam-engines, with the remains of
plants of ancient forms and extinct
species, which were swept from
the earth ere the formation of the
transition series was completed.
Thus, from the wreck of forests
that waved upon the surface of the
primeval lands, and from ferrugi-
nous mud that was lodged at the
bottom of the primeval waters, we
derive our chief supplies of coal
and iron ; those two fundamental
elements of art and industry, which
contribute more than any other
mineral production of the earth, to
increase the riches, and multiply
the comforts, and ameliorate the
condition of mankind.
COAL MEASURES. (The Terrain Ho-
uiller of the French, the Steinkoh-
lengebirge of the German geologists.)
The name given to one division of
the carboniferous group. The coal
measures consist of beds of coal,
sandstone, and shale, irregularly
interstratified, sometimes mixed

with conglomerates. ' * The organic
remains discovered in the coal
measures are principally terrestrial
plants ; with these are a few fresh-
water shells, and certain marine
exuvia3, which, for the most part,
would rather appear to occur in
beds alternating with the coal beds
and their accompanying shales and
sandstones, than mingled with the
terrestrial remains." Thirty-five
genera and three hundred and ten
species of plants have been dis-
covered: ten genera and fourteen
species of conchifers : four genera
and fourteen species of mollusks:
and two genera and three species
of fishes. — De la Beche. — Manual
of Geology.

COA'BCTATE. (coarctatus, Lat.) Press-
ed together. A term used in en-
tomology, to express that state
wherein the larva is.

CO'BALT. (The word cobalt seems to
be derived from colalm, or kobold,
the name of a spirit, or goblin,
that, according to the superstitious
notions of the times, haunted mines,
destroyed the works of the miners,
and often gave them much un-
necessary trouble. It was once
customary in Germany to introduce
into the church service a prayer
that God would preserve miners
and their works from kobalts and
spirits.)

This metal is of a gray colour,
with a shade of red, with but little
lustre ; its texture is fibrous ; spe-
cific gravity 8'6, or according to
some 7 '8. Fusible only at a
temperature of 16-677 of Fahren-
heit. When heated, cobalt is
partly malleable; it is permanently
magnetic. The fine blue mineral
called zaffre is an impure oxide of
this metal. The colour of this
oxide is so intense that a single
grain of it will impart a full blue
to 240 grains of glass. An oxide
of cobalt, dissolved in muriatic
acid, forms a sympathetic ink;

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the characters written with it
being invisible when cold, but on
exposure to heat assuming a bright
green colour, which on cooling
they again lose. The principal use
of cobalt is to give to glass and
porcelain a beautiful blue colour.

CO'BBLE. ) A pebble. This

CO'BBLE-STOITE. ) word is given by
Kay as belonging to the northern
counties. Cobble has the same
signification as boulder.

COCCI'FEROTJS. (from KOKKO-S, a berry,
and fero, to bear.) Any plant or
tree bearing berries.

CO'CCOLITE. (from KOKKOS, a grain, and
\t0os, a stone, Gr.) A mineral of a
green colour, a variety of augite :
called also Granular Augite.

COCCO'STETJS. (from KOKKOS, a berry,
and oseoi/, a bone, Gr.) An
ichthyolite of the lower old red
sandstone. Hugh Miller says,
"the figure of the coccosteus I
would compare to a boy's kite.
There is a rounded head, a tri-
angular body, a long tail attached
to the apex of the triangle, and
arms thin and rounded where they
attach to the body. The manner
in which the plates are arranged
on the head is peculiarly beautiful.
There are two marked peculiarities
in the jaws of the coccosteus.
The teeth, instead of being fixed
in sockets, like those of quadrupeds
and reptiles, or merely placed on
the bone, like those of fish of the
common variety, seem to have been
cut out of the solid, like the teeth
of the saw, or the teeth in the
mandibles of the beetle, or in the
nippers of the lobster. The posi-
tion of the jaws is vertical not
horizontal, and yet the creature
belonged to the vertebrata. Four
species are established. The aver-
age length of the coccosteus some-
what exceeds a foot.

CO'CCYGAL. | Pertaining to the coccyx,

COCCYGE'AL. ) or terminating bones
of the spinal column,

COCCYX. The terminating bones of
the spinal column. In the human
subject the coccyx consists of four
caudal or coccygal vertebrae, which,
however, often unite into one
undivided portion. In most mam-
malia, their number is far greater.

CO'CHLEATE. | Twisted like a screw,

CO'CHLEATED. ) or the shell of a
snail ; of a screwed or turbinated
form.

CO'CKLE. A term applied by the
Cornish miners to either schorl or
hornblende.

Co'cos. Petrifactions resembling nuts
of that genus.

COSLENTERA'TA. A sub-kingdom of
the kingdom animalia ; comprising
two classes, Actinozoa and Hydro-
zoa.

CCE'LIAC. Relating or pertaining to
the abdominal cavity, or belly.

COLEO'PTEBA. (from KoXeos, a sheath,
and Tnepov, Gr. a wing.) An order
of insects, having four wings, the
two upper being crustaceous, and
forming a shield. The second order
of the class insecta. This order is
divided into five sub-orders, con-
taining many families and tribes.

COLEO'PTEROUS. Belonging to the
order Coleoptera ; having a horny
hollow case under which the wings
are folded. Coleopterous insects
have four wings, the two superior
resembling horizontal scales, and
joining in a straight line along the
inner margin; the inferior wings
are merely folded transversely, and
covered with cases, commonly called
elytra.

CO'LLYRITE. The name of a hydrated
silicate of alumina, in which there
is one equivalent of silica to two of
alumina.

CO'LOLITE. (from KW\OV, and X/0os,
Gr.) The name given to the fossil
intestines of fishes by M. Agassiz.

CO'LON. (KW\OV, Gr. colon, Lat. colon,
Fr.) One of the large intestines,
and by much the longest. The

COL

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colon commences in the crecum,
and terminates in the rectum.

COLO'PHONITE. (from /co\o0oWa, Gr.

resin.) So named from its resin
colour. The grenat resinite of
Haiiy. Found near Pitigliano, in
Italy, and in Norway. A brown
or red variety of dodecahedral
garnet, having a resino-adamantine
lustre ; it is chiefly found at
Arendal, in Norway. It consists
of silica 37, alumina 13-6, lime 29,
oxide of iron 7'4, magnesia 6f5,
oxide of manganese 4*7, oxide of
titanium 0-5, water I/O. Specific
gravity 3*5.

COLT/MBITE. A mineral ore, the ore
of columbium.

COLU'MBIUM. A metal first discovered
in 1801 by Mr. Hatchett in a
mineral brought from North Ameri-
ca, from which it received its
name. It is of a dark grey colour,
very dense, and difficult of fusion.
This metal takes fire when heated
in contact with air, and burns into
columbic acid, which consists of
85 columbium and 24 oxygen.

COLTJMBE'LLA. A genus of spiral
univalve shells; they are thick,
oval or angular; spire shut, aperture
long and narrow, terminating in
an anterior canal; the outer lip
is thick and dentated, inner lip
crenulated. The C. sulcata is
recorded from the Crag of Walton
on Naze. — Lyceit.

COLUME'LIA. (Lat.) ^Inconchology,
the upright pillar in the centre of
most of the univalve shells.

CO'LTJMN. In botany the central point
of union of the partitions of the
seed-vessel, (that is in a capsule
containing many cells) to which
the seeds are usually attached.

COLTJ'MNAR. Formed in columns ;
having the form of columns ;
having the circumference always
circular, but the thickness indeter-
minate. In this last character
columnar differs from cylindrical;

cylindrical bodies being equally
thick throughout.

CO'MATE. (comatus, Lat.) Hairy. In
entomology, having the upper part
of the head, or vertex, alone covered
with long hairs.

COMA.'TTJLA. An existing genus of
radiaria of the family of Crinoidea.
The comatula presents a conformity
of structure with that of the pen-
tacrinite, almost perfect in every
essential part, except that the
column is either wanting, or at
least reduced to a single plate.
Peron states that the comatula
suspends itself by its side arms
from fuci, and in this position
watches for its prey, and obtains it
by its spreading arms and fingers.
— Miller. Four species of the genus
comatula discovered at Solenhofen,
in the oolite, have been determined
by Goldfuss, namely, C. filiformis,
C. pectinata, C. piunata, and C.
tenella.

COMB. ] These words, thus differently

COMBE. > written, appear to be of

COOMB. ) Saxon origin. Eay gives
the second as a south and east
country word, and defines it to be
a valley, " vallis utrinque collibus
insita." Lyell states it to be a
provincial name for a valley on the
declivity of a hill, and which is
generally without water. Buckland
says, "the term Combe is usually
applied to that unwatered portion
of a valley, which forms its con-
tinuation beyond, and above the
most elevated spring that issues
into it; at this point, or spring-
head, the valley ends and the combe
begins." A narrow undulating
ravine.

COMBU'STION. (combustion, Fr. com-
bmtione, It.) Consumption by fire;
the disengagement of light and heat
which accompanies chemical com-
bination.

CO'MMISSURE. (commissure*, Lat.) A
joint, seam, or suture.

CON

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COMMON OPAL. The Gemeiner opal

. of Werner. L'Opale commune of

Broehant. Quartz resinite commun

of Haiiy. A subspecies or variety

of opal. See Opal.

COMMON GAENET. (The Gemeiner
granat of Werner.) An earthy
mineral of a reddish-yellowish, or
blackish - brown color, differing
from precious garnet only in being
opake or translucent. It occurs in
granular masses, and crystallized
in dodecahedrons. See Garnet.

COMPA'CT. A term used in mineral-
ology when no particular or distinct
parts are to be discerned in a
mineral ; a compact mineral cannot
be cleaved or divided into regular
or parallel portions. It is some-
times confounded with the term
massive. — Phillips.

COMPACT FELDSPAR. The name assigned
to one of the feldspathic trappean
rocks.

COMPEE'SSED. (compressus, Lat.)

1. In botany, leaves are so termed
when flattened laterally.

2. In conchology, having one valve
flatter than the other.

CO'MPTONITE. A mineral thus named
after Lord Compton, who first
brought it to England, it is found in
the erupted matter of Yesuvius.

CONCAMEEA'TION. (concameratio, Lat.)
An arched chamber. In conchology,
concamerations are those small cham-
bers into which inultilocular shells
are divided by transverse septa, as
in the nautilus, ammonite, &c.

CONCE'NTEIC. (concentrique, Fr. con-
centrico, It.) Having one common
centre, as the coats of the onion;
running to a centre. A term
applied to the direction taken by
the lines of growth in spiral bodies.

CONCE'NTETC LAME'LLAE. A term used
to describe the appearance of a
body which being of a spherical
form has received succeesive cover-
ings or depositions.

CO'NCHIPEE. A class of mollusca,
the constructors and inhabitants

of bivalves. All turbinated and
simple shells are constructed by
molluscs of a higher order than the
conchifers, which construct bivalves;
the former have heads and eyes;
conchifers are without either, and
possess but a low degree of any
other sense than touch and taste.
Thus the whelk is an animal of a
higher order than the muscle or
oyster. — BucUand.

CONCHI'FEBA. Constitues the second
class of Mollusca. It comprises
the cockle, oyster, mussel, and all
ordinary bivalve shells.

CO'NCHITE. } (conchytes, Fr. coquittes

CO'NCHYTE. j pttrifies.} A petri-
fied, or fossil, shell.

CO'NCHOID. In geometry, the name
given to the curve invented by
Nicomedes.

CONCHOI'DAL. Shelly; shell-like. The
fracture of flint is said to be con-
choidal, that is to resemble a shell,
having convex elevations and con-
cave depressions.

The surface of fracture is termed
conchoidal when it more or less
resembles the appearance of a shell ;
thus, there are the perfect, imper-
fect, large, small, and flat con-
choidal.

CONCHOIDAL HOENSTONE. The Musch-
licher Hornstein of Werner. A
subspecies of Hornstone, occurring
in metalliferous and agate veins,
also in striped jasper, and in
pitchstone porphyry. See Horn-
stone.

CONCHOLE'PAS. A genus of oval,
vaulted, univalvular mollusks ; one
species only is known, the concho-
lepas Peruviana, brought from Peru.

CONCHO'LOGY. (from KO^XV, concha,
and XoV/os, Gr. conchyliogogie, Fr.)
That branch of natural history
which treats of testaceous animals,
or animals having a testaceous
covering, whether they inhabit the
ocean, or fresh water, or the land.

It is upon the exclusive shape
of the shell, and not the animal

CON

r.

inhabitant, that the arrangement
of conchology is founded. In
early periods, naturalists hesitated
whether to construct the arrange-
ment from the animal or the shell ;
it was, however, very wisely de-
termined that it should be from
the latter. The greater part of
shells are found without the ani-
mal in them, and all fossil shells
can only be determined by their
form. The Linna3an arrangement
of shells consists of three orders,
namely, Univalves, Bivalves, and
Multivales. Univalves consist of
shells complete in one piece, as the
cyprea, bulla, buccinum, &c. Bi-
valves are shells of two parts, or
valves, generally connected by a
cartilage, or ligament, as the oyster,
muscle, cockle, &c. Multivalves
are shells consisting of more parts
than two, as chiton, lepas, and
pholas. Every part of a shell
which is connected by a cartilage,
ligament, hinge, or teeth, is called
a valve of such shell. Of the three
orders of shells, the univalves are
the most numerous, both in genera
and species.

CONCHYLIOLI'THTJS. ) (from Keyx*/* a

CONCHY'LIOLITE. ) shell, and \i0os,
a stone, Gr.) A fossil shell.

CO'NDYLE. (*coV£v\os, Gr. oondylw,
Lat. condyle, Fr.) The condyles
are bony projections, or eminences,
at the ends of bones, as the condyles
of the shoulder-bone at the elbow ;
the condyles of the thigh-bone at
the knee.

CO'NDYLOID. (from icdvSv\o9 and e?£os,
form, Gr.) An apophysis of a bone ;
resembling a Condyle.

CONE. (/oDi/os, Gr. conus, Lat. c6ne,
Fr. cono, It.)

1. A solid figure having a circle
for its base, and terminating in a
point ; a figure resembling a sugar-
loaf.

2. The fruit of the fir-tree; a
catkin hardened, and enlarged into
a seed-vessel.

. ] CON

CONFE'BVA. A genus of plants, class
Cryptogamia, order Algse.

CONFEBVITES. Fossil remains of
plants belonging to the genus Con-
ferva.

CONFIGUBA'TION. (Fr. Forme exU-
rieure, ou surface qui "borne les corps,
et leur donne une figure particuliere.)

1. The form of a body in relation
to its various parts, and their
mutual adaptation.

2. The conjunction, or mutual
aspect of the planets.

CONFO'RMABLE. (conforme Fr. conforme,
It.) A term used in geology to
express parallel strata lying upon
each other, or when their general
planes are parallel to each other :
thus, when several horizontal
strata are deposited one upon
another, they are said to be in a
conformable position, but when
horizontal are placed over vertical
strata, they are said to be uncon-
formalle, so far as regards the
horizontal in relation to the vertical
strata.

CONFORMABLY. In agreement with
one another. Horizontal strata
placed on parallel strata lie con-
formally ; when placed on vertical
strata, or strata having an incli-
nation, or dip, they rest uncom-
formably.

CONFOBMA'TION. (conformatio, Lat.
conformation, Fr. conformazione, It.)
The form, shape, or structure of a
body, as regards the disposition of
the various parts, and their relation
to each other.

CONGE'NEBOTJS. (congenereux, Fr.)
Of the same kind or nature.

1. In anatomy, muscles which act
together to produce the same move-
ment are called congenerous.

2. In botany, plants of the same
genera.

CONGE'BIES. (Lat.) A collection of
many particles into one mass ; an
aggregate, or mass, of particles.

CONGLO'BATE. (conglolatus, Lat.) Ga-

CON

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thered together in a round ball;
conglobate glands are such as are
smooth in their surface, and seem
to be made up of one continued
surface.

CONGLOMERATE, (conglomeratus, Lat.)
This in geology has the same
meaning as breccia, and pudding-
stone. A mass of fragments united
by some cement. Geological
writers have chosen to define the
term variously, and oppositely,
to one another ; thus Lyell states a
conglomerate to be " rounded
water-worn fragments of rock or
pebbles, cemented together by
another mineral substance." Sim-
ply, gravel bound together by a
cement. Man tell defines it " frag-
ments cemented together." Bake-
well "large fragments of stone,
whether rounded or angular, and
imbedded in clay or sandstone."
Ure "a compound mineral mass,
in which angular fragments of rock
are imbedded. The Italian word
breccia has the same meaning."
Mantell in his " "Wonders of Geolo-
gy," p. 417, has " the most inter-
esting beds of these conglomerates,
or breccia, in this country."

CONGLOMERATE GLAND. A gland
composed of several glomerate
glands, whose excretory ducts
unite into one common duct : the
liver, kidneys, pancreas, &c. are
all conglomerate glands.

CONI'FERJE. (from comes and fero,
Lat.) An order of trees bearing
cones or tops, containing the seeds ;
the fifteenth order in Linnseus's
Fragmenta Methodi Naturalis, and
the fifty-first of his natural orders.
The Coniferee are plants whose
female flowers, placed at a distance
from the male, either on the same
or distinct roots, are formed into a
cone.

" The Coniferae," says Professor
Buckland, " form a large and very
important tribe among living plants,
which are characterised not only

by peculiarities in their fructifica-
tion, (having their seeds originally
naked, and not enclosed within an
ovary ; for which reason they have
been arranged in a distinct order,
as Gymnospermous Phanegoramise,)
but also by certain remarkable
arrangements in the structure of
their wood, whereby the smallest
fragment may be identified. The
recognition of these peculiar char-
acters in the structure of the stem,
is especially important to the geo-
logical botanist, because the stems
of plants are often the only parts
which are found preserved in a
fossil state. A transverse section
of any coniferous wood, in addition
to the radiating and concentric
lines, exhibits under the microscope
a system of reticulations by which
coniferse are distinguishable from
other plants. It appears that the
coniferae are common to all fossili-
ferous strata of all periods ; they
are least abundant in the transition
series, more numerous in the
secondary, and most frequent in
the tertiary series. All the trees of
this order secrete resin, have
branched trunks, and linear, rigid,
entire leaves : species are found in
the coldest as well as in the hottest
regions."

CO'NILITE. A genus of molluscous
univalves, placed both by Lamarck
and De Blainville in the family
Orthocerata. It is conical, straight,
or slightly curved.

"The difference between coni-
lites and baculites, is that the
external sheath of the latter is thin,
and not filled up with solid matter,
from the points of the alveole to the
apex, as in the former." — Sowerly.

CONI'STON FLAGSTONE. } The names
CONI'STON LIMESTONE, j assigned
to two divisions of the Upper Cam-
brian rocks. They answer to the
Upper Bala rocks, and Bala lime-
stone.

CON

[103]

COP

CO'NITE. An ash-coloured mineral,
becoming brown by exposure to
the atmosphere.

CONJUGATE, (conjugatus, Lat.) A
pinnate leaf having only one pair
of leaflets; leaves that consist of
one pair of pinnse or leaflets.

CO'NNATE. (connatum, Lat.) Applied
to leaves, when two leaves are so
united at their base as to have the
appearance of one leaf.

CO'NOID. (from KWVOS and e%o?, Gr.)
Resembling a cone in form ; sugar-
loaf shaped.

CONO'VTJLTJS. A genus of fossil ovate
pyramidal univalves occurring in
the Suffolk Crag, and formerly
attributed to Auricula.

CONTEMPORANEITY, (contemporaneity
Pr.) The state of being contempo-
rary with. "It becomes a very
curious problem to determine what
are the lines of contemporaneity in
the oolitic system." — Phillips.

CONULA'EIA. A genus of orthocerata,
of a conical shape, and polythala-
mous, the transverse septa being
imperforate. The conularia has
no siphon, and in this character
differs from orthoceras.

CO'NTTLTTS. A genus of echinites ; in
it are contained those which rise
from a circular base into a cone,
(from which form they obtain
their name,) with an acute or
obtuse vertex, from which five
pairs of punctated or crenulated
lines, or ambulacra, pass ; dividing
the shell into five large and five
small arese, that in which the anus
is placed being rather the largest.
All the species which constitute
the genus are known only as fossils,
and are distinguished by the modi-
fication of their form.

CO'NTJS. (*aui/o5, Gr. conns, Lat.)
Animal, a Limax ; shell univalve,
convolute, turbinate; aperture ef-
fuse, longitudinal, linear, without
teeth, entire at the base; pillar
smooth, This genus is divided by
some into five families. The recent

conus is an inhabitant of the ocean,
and is generally found on rocky
shores. Some of the shells are
very beautiful, and are both rare
and valuable; one species, the
cedo nulli, is valued at one hundred
guineas. The conus does not in-
habit our seas.
COOMB.

COOMBE.

CO'PPEE. (cuprum, Lat. kupfer, Germ.
hoper, Dutch. The word is derived
from the island of Cyprus, where it
was first wrought.) When pure,
copper is of a red colour; its
specific gravity is from 8*6 to 8*9,
or nearly nine times as heavy as
water. Copper is found in primary
and secondary rocks, and is often
native, i. e. in a pure metallic
state ; it is also found crystallized.
In smell and taste copper is exces-
sively nauseous. It is very mal-
leable, next so in degree after
gold and silver, and can be ham-
mered out into extremely thin
leaves, so thin as to be blown
about by the slightest breeze.
In ductility it ranks after gold,
silver, platinum, and iron; while
in tenacity it yields only to iron.
A copper wire one-tenth of an inch
in diameter will sustain a weight
of 385 Ibs. Copper is the most
sonorous of all metals : its fusing
point is 1450 Pah., and it can be
volatilized by an increased tempe-
rature; when allowed to cool
slowly, it assumes a crystalline
form. At common temperatures,
copper is not acted on by water,
but, if long exposed to the action
of the atmosphere and moisture, it
oxidizes; as it does in the air
alone, if heated to redness. It
combines with oxygen in two
proportions. Copper admits of a
greater degree of condensation by
hammering than any other metal.
Copper has been known from the
earliest ages. As stated before, it
occurs frequently in the native

COP

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state, either in masses, grains, or
crystallized in cubes and octohe-
drons. The most abundant, and
most generally diffused ore, and
that from which the metal is chiefly
obtained, is thesulphuret of copper,
termed copper pyrites, composeJd of
copper, sulphur, and a small portion
of iron. Copper has never been
combined with carbon, hydrogen,
or azote ; but it combines readily
with sulphur and phosphorus,
forming with them compounds
called sulphuret and phosphuret of
copper. Copper, having the prop-
erty of increasing the hardness of
gold without injuring its colour, is
used in the making of gold coin ;
that of Great Britain is an alloy of
11 parts of gold and 1 of copper.

COPEPO'DA. The fourth order of the
class Crustacea.

CO'PPEBAS. (copparosa, It. couperose,
Fr. Jcupferwasser, Germ.) Sulphate
of iron; green vitriol. Sulphate
of iron has a fine green colour;
its crystals are transparent rhom-
boidal prisms, the faces of which are
rhombs, with angles of 79° 50' and
100° 10' inclined to each other at
angles of 98° 37' and 81° 23'. It
has a strong styptic taste, and
reddens vegetable blues. It is pre-
pared by moistening the sulphurets
of iron, which are found native in
abundance, and exposing them to
the open air. These are slowly
covered with a crust of sulphate
of iron, which is first dissolved in
water and, subsequently, by means
of evaporation, obtained in crystals.

C'OPPLE-STONES. Boulders ; cobble-
stones, which see.

CO'PROLITE. The petrified fascal
matter of carnivorous reptiles ; the
petrified faecal remains of certain
fishes. The following description of
coprolites is taken from a memoir
on the subject, by Professor Buck-
land, published in the transactions
of the Geological Society, as well
as from his splendid Bridgewater

Treatise : — " In variety of size and
external form, the coprolites re-
semble oblong pebbles or kidney
potatoes. They, for the most part,
vary from two to four inches in
length, and from one to two inches
in diameter. Some few are much
larger, and bear a due proportion
to the gigantic calibre of the largest
ichthyosauri; some are flat and
amorphous, as if the substance had
been voided in a semifluid state ;
others are flattened by pressure of
the shale. Their usual colour is
ash-grey, sometimes interspersed
with black, and sometimes wholly
black. Their substance is of a
compact earthy texture, resembling
indurated clay, and having a con-
choidal and glassy fracture. Their
structure is in most cases tortuous,
but the number of coils is very
unequal ; the most common number
is three. Some coprolites, especial-
ly the small ones, shew no traces
of contortion. The sections of these
fa3cal balls, show their interior to
to be arranged in a folded plate,
wrapped spirally round from the
centre outwards, like the whorls of
a turbinated shell ; their exterior
also retains the corrugations and
minute impressions, which, in their
plastic state, they may have re-
ceived from the intestines of the
living animals. Dispersed irregu-
larly throughout the petrified faces,
are the scales, and occasionally the
teeth and bones, of fishes, that seem
to have passed undigested through
the bodies of the saurians ; just as
the enamel of teeth, and sometimes
fragments of bones, are found un-
digested both in the recent and
fossil album gracum of hyaenas."
On the shore at Lyme Regis, in
Dorsetshire, coprolites are found in
great abundance, lying scattered in
the ground like potatoes. The true
character and real nature of the
coprolite was long misunderstood,
having formerly been called Juli,

COB

[ 105 ]

COR

and believed to be fossil fir cones.
The animal origin of coprolites had
previously been suggested by
M. Konig, but it is to the investi-
gation of these substances by Pro-
fessor Buckland, and to his sa-
gacity, that we owe our present
knowledge of their true nature.
Coprolites are found in all strata
which contain the remains of
carnivorous reptiles. The real
origin of these coprolites is placed
beyond all doubt, by their being
found frequently within the intes-
tinal canal of fossil skeletons of
ichthyosauri. The preservation of
such faecal matter, and its lapidifi-
cation, result from the imperishable
nature of the phosphate of lime,
one of the constituents of bony
matter.

COPEOLI'TIC. Composed of coprolites ;
resembling coprolites; containing
coprolites.

COQUILLA'CEOUS. Containing shells.
A term applied by some authors to
strata abounding in shelly remains.

COEACOID. (from Kopag, a crow, and
etoos, Gr.) Resembling the beak
of a crow. A name given to the
upper anterior point or process of
the scapula.

CO'RAL. (icopa\\iov, Gr. corallium,
Lat. corail, Fr. coralla, It. It is
somewhat marvellous to find Todd
following Johnson in his description
of coral, and stating it to be a
plant.) The red coral is a branched
zoophyte, somewhat resembling in
miniature a tree deprived of its
leaves and twigs. It seldom exceeds
one foot in height, and is attached
to the rocks by a broad expansion
or base. It consists of a bright red,
stony axis, invested with a fleshy,
or gelatinous substance, of a pale
blue colour, which is studded over
with stellular polypi. Coral is
composed of carbonate of lime and
animal matter. The powers of the
organic creation, says Lyell, in
modifying the form and structure

of the earth's crust, which may be
said to be undergoing repair, or
where new rock formations are
continually in progress, are most
conspicuously displayed in the la-
bours of the coral animals. We
may compare the operations of
these zoophytes in the sea to the
effects produced on a smaller scale
upon the land, by the plants which
generate peat. In corals, the more
durable materials of the generation
that has passed away serve as the
foundation on which living animals
are continuing to rear a similar
structure. Of the numerous species
of zoophytes which are engaged in
the production of coral banks, some
of the most common belong to the
genera meandrina, caryophyllia,
millepora, and astrea, but especially
the latter. It has been asked,
" From whence do these innume-
rable zoophytes and molluscous
animals procure the lime, which,
mixed with a small quantity of
animal matter, forms the solid
covering by which they are pro-
tected ? Have they the power of
separating it from other substances,
or the still more extraordinary
faculty of producing it from simple
elements ? The latter I consider
the more probable ; for the polypi
which accumulate rocks of coral
have no power of locomotion ; their
growth is rapid, and the quantity
of calcareous matter they produce,
in a short space of time, can scarce-
ly be supposed to exist in the
waters of the ocean to which they
have access, as sea- water contains
but a minute portion of lime." Le
Sueur, who observed them in the
West Indies, describes these poly-
pes, when expanded in calm
weather at the bottom of the sea,
as covering their stony receptacles
with a continuous sheet of most
brilliant colours. Ehrenberg, the
distinguished German naturalist,
was so struck by the splendid

COR

spectacle presented by living poly-
paria covering every portion of the
bottom of the Eed Sea, that he is
said to have exclaimed. " "Where
is the paradise of flowers that can
rival in variety and beauty these
living wonders of the ocean. —
Lyell. Mantell. BucklanA. Bak&well.

COEALLI'FERI. An order of polypi,
embracing those species which were
so long considered to be marine
plants.

CO'RALLINE. Belonging to the class
Zoophyta, order Eschara, each
polypus being contained in a cal-
careous or horny shell, without any
central axis. The animal which
secretes and inhabits coral. Fossil
corallines abound among the radiata
of the transition series, proving that
this family had entered thus early
upon the important geological func-
tions of adding their calcareous
habitations to the solid material of
the strata of the globle.

CO'EAL-EAG. (So named from an
abundance of fossil corals generally
found in it.) A member of the
middle division of oolite, of the
thickness of about forty feet, in the
Bath district. "The coral-rag of
England, and analogous zoophytic
limestones of the oolitic period in
different parts of Europe, bear a
resemblance to the coralline forma-
tions now in progress in the seas of
warmer latitudes." — Lyell. The
coral-rag comprises a series of beds,
occupying in some places a thick-
ness of from one to two hundred
feet.

CO'EAL EEEF. \ It is a curious, but

CO'EAL ISLAND, j indisputable fact,
that a considerable portion of the
earth's surface is the result of
organic secretion, and the same
process is still going on extensively
in the Pacific and Indian seas,
where innumerable coral islands
rise above, and innumerable reefs
and shoals lie just below, the surface
of the waves. The observations of

[ 106 ] C 0 £

modern voyagers have thrown much
light on the formation of coral is-
lands and reefs ; they concur in the
opinion that these reefs and islands
do not rise from the depth even of
many hundred yards, but commence
on the summit of some volcanic
elevations, or other submarine ridges
and rocks, not far below the surface
of the sea. M. M. Quoy and Gai-
mard observe that the species which
form the most extensive banks belong
to the genera Meandrina, Caryo-
phyllia, and Astrea, but especially
to the latter; and that these genera
are not found at depths exceeding
a few fathoms. The calcareous
masses usually termed coral reefs
are by no means exclusively com-
posed of zoophytes; a great variety
of shells, and among them some of
the largest and heaviest of known
species, contributing to augment
the mass. The reefs, which just
raise themselves above the level of
the sea, are usually of a circular or
oval form, and surrounded by a
deep, and often unfathomable ocean.
In the centre of each, there is
usually a comparatively shallow
lagoon, where there is still water,
and where the smaller and more
delicate kind of zoophytes find a
tranquil abode, while the stronger
species live on the exterior margin
of the isle. When the reef is of
such a height that it remains almost
dry at low water, the corals leave
off building. Fragments of coral
limestone are thrown up by the
waves, until the ridge becomes so
high, that it is covered only during
some seasons of the year by the
high tides. The heat of the sun
often penetrates the mass when it
is dry, and splits it. The force of
the waves subsequently separates
blocks of the coral and throws them
upon the reef. Afterwards the
calcareous sand, removed from the
action of the waves, lies undis-
turbed, and offers to the seeds of

COB

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trees and plants, cast upon it by
the waves, a soil upon which they
rapidly vegetate. Wherever cir-
cumstances are compatible with
vegetable life there we find plants
arise. Islands formed by coral
reefs, which have risen above the
level of the ocean, become, in a
short time, covered with verdure.
The slightest crevice or irregularity
is sufficient to arrest the invisible
germs that are always floating in
the air, and affords the means of
sustenance to diminutive races of
lichens and mosses. These soon
overspread the surface, and are
followed, in the course of a few
years, by successive tribes of plants,
gradually increasing in size and
strength, till, at length, the island
is converted into a natural and
luxuriant garden. Entire trunks
of trees, carried by the rivers from
other countries, find here a resting-
place : with these come small
animals, such as insects, lizards,
&c., as the first inhabitants. Even
before the trees form a wood, the
sea-birds nestle here; strayed land-
birds take refuge in the bushes:
and at a much later period, man
appears, and builds his hut on
the fruitful soil.— Phillips. Lyell.
JZbtzebue. Balcewell.

COEALLI'GENOTJS. Producing coral.
The depth at which the coralli-
genous zoophyta commence their
labour is said not to exceed fifteen
or twenty fathoms.

COEALLINE CEAG. The crag of Suffolk
consists of two portions, namely,
Red crag and Coralline crag. The
coralline crag is the older of the
two, and is a mass of soft marly
sands of a white colour.

CO'EALLOLD. } (from coral and e?£os,

COEALLOI'DAL. j Gr.) Resembling
coral ; having the form of coral.

COEALLO'IDES. (coralloides , Fr. seme
del corallo lianco, It.) Coral- wort;
the clavaria coralloides of Linnaeus.

COBBIS. A bivalve genus of shells
belonging to the family Nymphacea
of Lamark ; it is equivalve, nearly
equilateral, oval, thick, ventricose,
the hinge has two lateral and two
cardinal teeth in each valve. The
only recent species, C. fimbriata, is
an inhabitant of the Indian ocean ;
several fossil species are recorded
from the eocene strata at Crignon,
and upwards of six are known in
the oolitic rocks of England. —
Lycett.

CO'EBTJLA. (corlula, Lat.) A genus
of bivalves belonging to the family
Corbulacea in Lamarck's arrange-
ment, and to that of Conchacea in
De Blainville's. The corbula is a
marine animal, found at depths
varying to thirteen fathoms, in
sandy mud. Some authors place
the genus corbula in Solen, others
in Mya. Corbulse are found both
fossil and recent. Fossil corbulse
occur in the London clay, calcaire
grossier, and Norfolk crag. They
are also found in the Shanklin
sand, at Parham, and elsewhere.

COEBULA'CEA. A family of bivalves
in Lamarck's system, belonging to
the order Dimyaria, and compri-
sing the two genera Pandora and
Corbula.

COEDI'EEITE. A mineral, so named
by Leonhard after Qordier. It is
better known as lolite, or prismatic
quartz, which see.

COE-MAEINTJM. A genus of echinites,
characterized by the bilabiated
mouth being in the third region of
the axis of the base, and the
anus in the side of the truncated
extremity. In this genus, or, as
he terms it, family, Leske, with
Muller, includes spatangus, spata-
goides, brissus, and brissoides, not
considering the absence of the
groove to be a generic distinction.
— Parkinson.

COEI'NDO]*. Another name for corun-
dum or spinel.

con

[ 108]

C 0 K

CO'BXEA. (from cornu, Lat. cornte,
Fr. cornea dell'occhio, It.) The
anterior transparent portion of the
ball of the eye, or that portion of
the front of the eye which allows
the rays of light to pass through,
and permits objects to be reflected
on the retina at the back.

CO'KNEAN. A name applied by De la
Beche to designate a variety of
Trappean rocks met with in Pem-
brokeshire, which rocks may be
divided into felspathic, quartzose,
and hornblendic, as those minerals
prevail in the mass.

CO'ENEANITB. The name assigned by
Dr. Boase to a genus of rocks
having a basis of compact felspar
combined with hornblende, which
latter is generally in a smaller pro-
portion than in greenstone. Cor-
neanite sometimes contains particles,
granules, and minute veins of calc-
spar: sometimes it abounds in
granules and nodules of quartz :
sometimes it contains veins of anti-
mony and lead ; but it more
abounds in manganese.

COBNE'LIAN. For an account of this
sub-species of calcedony, see Car-

CO'BNEAN. The name given to a fels-
pathic trappean rock.

COBNEOC/ALCITE. The name proposed
by Dr. Boase to be given to a dark
limestone, abundantly occurring in
Cornwall. It is composed of
carbonate of lime, with hornblende
and compact - felspar. Of this
genus Dr. Boase enumerates six
species.

CO'ENBEASH. A coarse shelly lime-
stone ; a provincial term. Corn-
brash is a marine deposit, a member
of the oolite ; it occurs in Wiltshire.

CO'RNSTONE. A mottled, red and green
limestone, occurring in the old red
sandstone. The name of this and of
the preceding word may be consider-
ed as provincial, and given to them
from their presumed utility in
producing fertile corn-land. Sir E.

Murohison has divided what he
terms the old red system into three
parts, the central of these is the
Cornstone Formation. He says
"the central masses of this system
are chiefly composed of red and
green argillaceous spotted marls,
affording, on decomposition, the soil
of the richest tracts of the counties

in which it occurs.'

There

is no district in which the nature
and relations of the cornstone can be
better studied than to the north of
Ludlow, where this formation
occupies a distinct range of hills,
rising to the height of four or five
hundred feet above the low country,
and presenting escarpments to the
valley of Corvedale. The spotted
marls can never be distinguished
from those of the new red sandstone,
except, perhaps, when; they are
separated from each other by beds
of hard, micaceous, sandstone.
"Wherever the order of superpo-
sition is not apparent, the fragments
of fossil fishes which occur in
abundance throughout the corn-
stones, and which were first
detected by Dr. Lloyd, of Ludlow,
constitute the best distinction
between this formation and the
lower new red sandstone, which it
so much resembles. These fishes
are of very peculiar forms, and
their fragments being often of
brilliant purple and blue colours,
are excellent points of attraction
for the eye of the geologist; pre-
senting a striking contrast to the
surrounding dull red and green
matrix in which they are enveloped.
The cephalaspis appears to be a
characteristic fossil of the corn-
stone.

COENUB'IANITE. (from Cornubia, the
Latin name for Cornwall.) Dr.
Boase proposes to apply the name
of Cornubianite to the rock hither-
to distinguished by the name of
Killas: he says that the killas
appears to constitute a rock sui

COR

gtneris-, which ought to be dis-
tinguished by a peculiar denomi-
nation; and as it is exceedingly
rich in tin and copper ores (being
the principal seat of the Cornish
mines) the name of cornubianite
might be adopted. Cornubianite
consists of a basis of compact
felspar, coloured by a dark mineral
resembling mica, with which it is
not only intimately combined, but
also contains this mineral in distinct
granules, or scales, variously dis-
posed. This rock always occurs in
contact with granite ; by numerous
beds and veins of which, it is
frequently intersected. Dr. Eoase
enumerates six species of cornubi-
anite, namely, compact, quartzose,
lamellar, striped, micaceous, and
schistose.

COEO'LLA. (Lat.) The corolla con-
sists of the delicate petal, or petals,
forming, what, in common lan-
guage, are termed the blossoms;
and in polypetalous flowers, the
petals are usually called the leaves
of the flower. The corolla consti-
tutes the beauty of the flower, and
the odour and fragrance of the
plant frequently reside therein, as in
the rose, jessamine, violet, &c. The
corolla has a diversity of forms, as
well as of colour, being found of
every shade and variety except
black. It includes two parts, the
petals and the nectary ; the latter
is sometimes a part of the former,
and sometimes separate from it.
The leaves of the corolla are called
petals, and these are either distinct,
when the corolla is termed poly-
petalous, as in the rose, ranunculus,
&c. or they are united by their
edges, in which case the corolla is
said to be monopetalous, as in the
honey-suckle, convolvulus, &c. The
corolla is either regular or irregular ;
when the petals are all alike in
size and form, the corolla having a
symmetrical appearance, it is called
regular ; but when the petals are

[ 109 ] C 0 K

unequal, or unlike each other, it is
termed irregular, as in the pelargo-
nium, violet, &c. A papilionaceous
corolla consists of five petals of
particular forms, of which the
uppermost is turned back, and is
called the vexillum or standard;
the two next resemble each other,
but differ from the first ; they have
their faces towards each other;
they are called the alaB, or wings :
the remaining two, which are
placed below the others, also re-
semble each other, but differ from
the three already mentioned ; they
are usually united by their lower
edge, and form a figure resembling
the keel of a boat, whence they
obtain the name of carina, or keel.
This corolla is the characteristic of
th« Ieguminosa3, a very large order
of plants, of which the broom,
lupin, sweet-pea, vetch, &c. are
examples.

In some plants the corolla has
one or more of its petals spurred,
as in the violet.

In the orchidese, the corolla
consists of three pieces, one differ-
ing very greatly in form and size
from the other two ; it is called the
lalellum or little lip, and is often
spurred. In many species, this
resembles an insect.

The lower part of the single
petal of a corolla, by which it is
fixed to the receptacle, is named
the claw.

The cruciferous plants have four
petals, and these are so arranged as
to resemble a cross, from which
circumstance they have been named
Cruciferas. The stock, radish,
cabbage, mustard, &c. are examples.

The outer part of the heads of
many composite flowers is formed
of the ligulate corollas of the ex-
terior florets, and these are
commonly white, blue, or yellow,
as in the aster, daisy, &c. ; this
part of the head is termed the ray,
the central part being called the

COB

[ 110 ] COR

which disk is composed of
florets, with regular corollas.

A corolla with two lips is called
Ulabiate: when the two lips
present an appearance resembling
the mouth of an animal, the corolla
is called ringent.

The petals of all corollas are
placed alternately with the sepals
of the calyx.

COBO'LLIFLOEJS. In botany, the fourth
order of the class Exogens.

COBO'NA. (Lat.) In botany, an
appendage of the corolla or peri-
anth.

CO'BONXUD. See Coracoid.

CoBo'injLA. A regular subrotund, or
subconical shell, divided into
twelve areas, with an opening both
in the superior and inferior part ;
that in the superior closed by a
four-valved operculum.

CO'BONATED. (coronatus, Lat.) In
conchology, crowned, or girt
towards the apex, with a single row
of eminences.

CO'BPUSCLE. j (corpusculum, Lat.

CoEPifscuLE. ) corpuscule, Fr.
corpuscolo, It.) A minute particle
of a body ; an atom.

COBT/KDUM. (The Korund and
Demant-spath of "Werner : the
Corindon-harmophane of Hatty :
Corindon adamantin of Brongniart :
Adamantine spar of Kirwan.) A
genus of gems comprising four
species.

1. Spinel, or dodecahedral cor-
undum.

2. Automolite, or octahedral cor-
undum.

3. Sapphire, or rhombohedral cor-
undum.

4. Chrysoberyl, or prismatic cor-
undum.

These will ail be described under
their several names.

Some mineralogists constitute
corundum a species comprising
sapphire, corundum - stone, and
emery; others place corundum

amongst the members of the ruby
family, while some consider it to
be a sub-species of sapphire. The
colour of corundum is greenish-
white, sometimes nearly colourless,
passing into greenish-grey, occa-
sionally reddish; sometimes it
possesses a Berlin or azure blue, at
others it is of a cochineal or crim-
son red. Its colours are usually
weakened by exposure to heat.
Before the common blow-pipe it
does not yield but with borax,
but before the compound blow-
pipe, it fuses into a grey globule.
The form of the primitive of
corundum is a slightly acute rhom-
boid. It occurs in crystals as
well as in amorphous masses of a
moderate size, sometimes rolled.
Lustre of the cross fracture shining
and glistening. Fracture perfect,
foliated, with a four-fold cleavage.
Its infusibility and hardness serve
to distinguish it from all minerals
which it resembles in its external
characters. Specific gravity from
3-710 to 3-873. It consists of
alumina 91, silica 5, iron 1-5.
Corundum is found in India,
Malabar, the Carnatic, and other
eastern parts, and in Italy. It
occurs imbedded in primary rocks,
having scales of mica and felspar
frequently adhering to its surface.
It is employed in polishing gems
and other hard substances.

CO'BYMB. (corymbe, Fr. corymlm Lat.)
A kind of efflorescence. A raceme.
A spike of flowers, whose partial
peduncles take their rise from
different heights upon the common
stalk, but the lower peduncles being
longer than the upper ones, they
all form nearly a level surface at
the top.

COYY'HBIATED. Garnished with bun-
ches of berries or blossoms, in the
form of corymbs.

COBYMBI'FEBOTJS. (from corymlus and
feroj Lat.) Bearing berries or
blossoms in the form of corymbs.

COT

C K A

CORY'PHODON. (from Kopvfirj, a point,
and o£ove, a tooth, Gr.) The name
assigned by Prof. Owen to a sub-
genus of extinct fossil tapiroid,
one species of which, Coryphodon
Eocgenus, has been discovered in
the eocene clay, on the coast of
Essex.

COSMACANTHTJS MALCOLMSONI. A fossil

fish of the old red sandstone, de-
scribed by Agassiz in his Poissom
Fossiles.

COSMO'GONY. (/coo-^or/eVem, Gr. cosmo-
gonie, Fr.) The science of the
formation of the universe.

COSMO'GRAPHER. (from cosmographe,
Er. cosmografo, It. /coV/toe and<y/>a0w,
K0ff/u,orypd(fios, Gr.) One who de-
scribes the several parts of the
creation by writing.

COSMO'GRAPHY. (cosmographie, Er.
cosmogrcifia, It. Koafjio^pa^la, Gr.)
The science which describes the
several parts of the creation, de-
lineating them according to their
number, positions, motions, magni-
tudes, figures, &c.

COSMOLO'GICAL. (cosmologique, Fr.
Koa^oKo^iKos, Gr.) Pertaining to
the science of cosmology.

COSMO'LOGIST. A pursuer of the science
of cosmology; one who describes
the several parts of creation.

COSMO'LOGY. (cosmologie, Er. icofffio-
Xory/a, Gr.) The science which
treats of the general laws by which
the physical world is governed;
the study of the world in general.

CO'STA. (costa, Lat. plural costse.)
A rib.

CO'STAL. (costal, costale, Er.) Belong-
ing to the ribs.

CO'STATE. | (from costatus, Lat.)

CO'BTATED. ) Bibbed, or having
ribs.

CO'TTLE. (from Korv\rj, Gr. cotyl, Er.
cwoiti (Pun os dans laquelle un autre
08 s'artieule.) The cavity or socket
of a bone which receives another
bone in articulation, as the socket
of the hip which receives the head
of the femur, or thigh-bone.

CoTYLE/D03f . (KOTv\t]^iav , Gr. cotyledon,
Er.) The side lobe, or seed-lobe of
seeds, furnishing nourishment and
protection to the corculum, and
forming the chief bulk of the seeds:
these lobes swell and expand in the
ground, and as the stem ascends
they are usually raised out of the
ground, assume a green colour, and
perform the functions of leaves until
the young leaves unfold, when they
generally wither. The cotyledon
is found at the point of union of
the radicle and plumule. The
most essential difference in the
structure, mode of growth, and
character of the plants growing
from the seeds, is found connected
with the number or position of the
cotyledons. Those plants, the seeds
of which have only one cotyledon,
or if more, these alternate on the
embryo, are called monocotyledo-
nous. All monocotyledonous plants
can be recognized without any
difficulty, by a characteristic feature
of the leaf, the veins of the leaf
being parallel, and not reticulated ;
all the palms, the tulip, lily, aloe,
&c., are instances. Those plants
which have two cotyledons, and
those opposite, are called dicotyle-
donous; all dicotyledonous plants
have the veins of their leaves
reticulated.

COTYLE'DONOTTS. Having cotyledons.

COT/ZERANITE. A mineral so named
by Leonhard from its having been
found in the country called des
Couzerans.

CO'WBY. The common or familiar
name for shells belonging to the
genus Cypr&a.

CRAG. A tertiary deposit of the
older pliocene period, which has
obtained this name from a provin-
cial term signifying gravel. The
crag is chiefly developed in the
eastern parts of Norfolk and
Suffolk, extending thence into
Essex ; it is seen to rest on the
chalk and on the London clay, but

C R A

L

generally on the chalk. By some
the crag has been divided into two
groups, the lower, or coralline,
which is, in some places, fifty feet
or more in thickness, and the
upper, or red crag, thus named
from its ferruginous colour. The
• fossils of the crag are very nume-
rous. From an examination of a
collection of shells of the crag made
by M. Deshayes, it appears that
out of 111 species, 66 were extinct
or unknown, and 45 recent, the
last, with one exception, being in-
habitants of the German Ocean.
From this result Sir C. Lyell
concludes that the crag belongs to
the olden Pliocene period.

The sands of this formation vary
in colour from white, through
different shades of yellow, up to
orange-red : the colour proceeding
partly from a ferruginous stain, and
partly from the intermixture of
yellow oxide of iron.

CEA'NIA. (from cranium, Lat. a
skull, in consequence of a supposed
resemblance of the interior of the
shells to a skull, arising from some
deep muscular impressions.) A
regular inequivalved bivalve ; the
upper valve very convex, patelli-
form, with the umbo near the
centre, the lower valve flat, and
nearly round, and pierced internal-
ly with three unequal and oblique
holes. The arms of the animal are
ciliated. Cuvier places crania in
the class Brachiopoda, division
Mollusca. By Lamarck this genus
is placed in the family Rudistes,
order Monomyaria ; and by De
Blainville in the order Palliobran-
ehiata. Craniae are found attached
to stones and shells, and are
brought up, probably from great
depths, by cod-lines, off the coast of
Shetland, and with corals in the
Mediterranean. Several species of
fossil cranise are found in the chalk
formation.

CBA'SIDH. (Lat.) The skull.

2 ] ORE

CEASSATE'LLA. (from crassm, thick,
Lat.) A genus of equivalved in-
equilateral close bivlaves. The
hinge teeth two, with an adjoining
fossa; the lateral teeth obsolete.
The cartilage inserted in a pit
formed in the hinge.

As the crassatella advances in
age, the valves become very greatly
thickened, from which circumstance
it obtains its name. Cuvier places
this genus in the family Mytilacia,
order Acephela ; Lamarck, in the
family Mactracea; and De Blain-
ville, in the family Conchacea.

Recent crassatellas inhabit sandy
mud at depths varying from eight
to twelve fathoms. Some species
of fossil crassatellae have been
found in the tertiary formations.

CEA'SSINA. The name assigned by
Lamarck to a genus of shells. See
Astarte.

CRE'NATE. } (crenatus, Lat.) Notched

CEE'NATED. j at the margin ; scol-
loped ; indented.

1. It is applied to leaves when
the notches or teeth on the borders
are rounded, and the notches not
directed to either end of the leaf.

2. In entomology, a margin with
indentations, not sufficient to be
called teeth, the exterior whereof
is rounded.

CBE'NATTTEE. The notch or indenta-
tion of a leaf.

CEEN'ATULA. (from erenatm, Lat.)
This name has been given to a
genus of bivalves from the hinge
showing a row of roundish or oval
pits, making it appear as if crenu-
lated. An irregularly formed flat
bivalve ; closed, not giving passage
to any byssus ; the hinge linear,
excavated, and crenulated ; um-
bones terminal. It is found in
sponges, and moored to coral-lines,
&c. Parkinson, in describing the
crenatula, says, "there are very-
few among the fossil shells of this
or of any other country, which, at
first sight, are more dissimilar

CUE

C

from any of the recent shells, than,
the fossil crenatula" It is very
rarely found.

CRENELLA. A genus of bivalve con-
ehifera belonging to Lamarck's
family Arcacea, and established by
Brown.

CRE'NULATE. } (crenele, Fr.) Indent-

CRE'NTJLATED. ) ed round the mar-
gin with small notches. The fine
saw-like edge of the shell of the
cockle, which so nicely fits into
the opposite shell, is a familiar
example of a crenulated margin.

CRETA'CEOUS GROUP. This group com-
prises the different strata from the
chalk of Maestricht to the lower
green-sand inclusive. In LyelPs
Principles, they are thus arranged :
1. Maestricht beds ; 2. Chalk with
flints; 3. Chalk without flints ; 4.
Upper green sand; 5. Gault; 6.
Lower green -sand. The whole of
these formations are marine.

The cretaceous group are also
divided into Upper Cretaceous,
comprising the Maestricht and
Faxoe beds; white chalk, with
flints ; white chalk, without flints ;
chalk marl; upper green-sand;
and the gault ; and lower creta-
ceous or Neocomian, comprising
the lower greensand, the Speeton
clay, and the Wealden Beds.

CRI'CHTONITE. The name given to a
black, opaque, shining mineral,
after Dr. Crichton.

CRIO'CERATES. A genus of ammonites,
having the whorls disconnected.

CRINO'IDAL. Containing fossil cri-
no'idean remains. The Derbyshire
encrinital marble is composed prin-
cipally of the fossilized remains of
crino'idea, cemented together by
carbonate of lime.

Although the representatives of
crinoi'deans in our modern seas are
of rare occurrence, this family was
of vast numerical importance among
the earliest inhabitants of the
ancient deep. The extensive range
which it formerly occupied among

the earliest inhabitants of our
planet, may be estimated from the
fact, that the crinoi'deans already
discovered have been arranged in
four divisions, comprising nine
genera, most of them containing
several species, and each individual
exhibiting, in every one of its
many thousand component little
bones, or ossicula, a mechanism
which shows them all to have
formed parts of a well- contrived
and delicate mechanical instrument.
— Prof. Bucldand.

CRINO'IDEA. (from icplvov and ef£o?,
Gr.) "I have derived the name
of this family," says Miller, "from
the Greek -ra gwa Kpivoeidea, the
lily-shaped animals, and have used
this word, with another distin-
guishing term prefixed, to form
the name of the genera." Lily-
shaped zoophytes. In the most
modern classification, Crino'idea con-
stitutes the fifth order of the class
Echinodermata, and is divided into
seven families. A name given to the
whole class of encrinites and pen-
tacrinites, from their resemblance
to the head of the lily. " Of more
than thirty species of Crinoi'deans,"
says Prof. Buckland, "that pre-
vailed to such enormous extent in
the transition period, nearly all
became extinct before the deposition
of the Lias. We may judge of the
degree to which the individuals of
these species multiplied among the
first inhabitants of the sea, from
the countless myriads of their
petrified remains which fill so
many limestone beds of the tran-
sition formations, and compose vast
strata of entrochal marble, extend-
ing over large tracts of country in
Europe and America."

The fossil remains of this order
have been long known by the name
of stone lilies, or encrinites, and
have lately been classed under a
separate order by the name of Cri-
no'idea. This order comprehends

C E I

[

many genera and species, and is
ranged by Cuvier after the asterise,
in the division of zoophytes. The
skeleton of the crinoidea is com-
posed of numerous ossicula, the
number of bones in one skeleton
being computed at upwards of
thirty thousand. Mr. Miller, in
his work, entitled " a Natural His-
tory of the Crinoidea," thus defines
them r. " An animal with a round,
oval, or angular column, composed
of numerous articulating joints,
supporting at its summit a series of
plates, or joints, which form a cup-
like body, containing the viscera,
from whose upper rim proceed five
articulated arms, divided into ten-
taculated fingers, more or less
numerous, surrounding the aper-
ture of the mouth, situated in the
centre of a plated integument,
which extends over the abdominal
cavity, and is capable of being
contracted into a conical or pro-
boscal shape."

The existence and preservation
of the muscular portion of the
Crinoidea, have been proved by
Parkinson, who placed well pre-
served portions of columns in
diluted acid, which gradually
removed the calcareous matter,
and left the fine animal pellicle
behind.

The detached ossicula of the
crino'idea occur in myriads in the
mountain limestone and transition
rocks, forming successions of strata,
each many feet in thickness, and
miles in extent; showing how
largely the bodies of animals have
contributed by their remains, to
increase the mass of materials
which compose the mineral world.
If we imagine a star-fish to possess
a long flexible column, the base of
which is attached to a rock, we
shall have a correct idea of the
general character of the crino'idea,
or lily-shaped animals ; which are
so called from their fancied resem-

1 ] C R 0

blance, when in a state of repose,
to a closed lily. The columns and
columnar joints of the crinoidea,
by their frequent occurrence and
remarkable figure, attracted the
attention of naturalists at an early
period. The round columns and
their depressed single perforated
joints, marked upon the upper and
lower surfaces with radiating stria3,
have acquired names founded on
superstitious ideas, their resem-
blance to other bodies, and the use
they were applied to ; as rosary
beads, giant's tears, fairy stones,
wheel stones, trochites, entrochites,
&c. The angular columns, being
generally star-shaped, received the
names, star-stones, asteria3, &c.

The essentially distinguishing
character of the family of Crinoidea,
is the column formed of numerous
joints which separates them from the
Polypi, whilst the arms and fingers
surrounding the mouth, prove their
affinity to them and the Stellerida?.
Miller establishes four divisions
of the family of Crinoidea, namely,
Articulata, comprising the genera
Apiocrinites, Encrinites, and Pen-
tacrinites; Semiarticulata, genus
Poteriocrinites; Inarticulata, gene-
ra Cyathocrinites, Actinocrinites,
Rhodocrinites, and Platycrinites ;
and thirdly Coadunata, genus Eu-
geniacrinites. — BucUand. Mantell.
Miller.

CBINOIDE'AN Belonging to the order
Cirnoi'dea.

CBIO'CEKAS. A genus of Ammonites ;
proposed by M. Leveille, with
disconnected whorls; the Tropaeum
of Mr. J". Sowerby. The C. Bower-
bankii belongs to the lower green
sand of the Isle of "Wight; the
C. Duvalii and the C. Plicatilis to
the Speeton clay of Yorkshire. —
Lycett.

CBO'CODILE. (/c/jo/co'^etXos, Gr. croco-
dilus, Lat. croccodillo, It. crocodile,
Fr.) An amphibious voracious
animal of the order Crocodilia,

C R 0

[

family Reptilia. It is covered with
very hard scales, which can be
pierced with great difficulty,
except under the belly. It has
four feet, and a tail, with five toes
on each of the fore, and four toes
on each of the hind feet, of which
only the three internal ones on
each foot are armed with nails. It
has a wide throat, with several
rows of teeth. The fossil remains
of crocodiles are common and abun-
dant. Crocodiles are omnivorous.
The living species of the crocodile
family are twelve, one Gavial,
three Alligators, and eight true
Crocodiles. Crocodiles, it is said,
continue to grow throughout the
whole of their existence, and
Buckland states their increase to
be no less than four hundred times
their original bulk, between the
period at which they leave the egg
and their full maturity. Crocodiles
are furnished with a frequent suc-
cession of teeth, in order to
maintain a duly proportioned
supply during every period of their
life. The vertebrae of the neck
rest on each other through the
medium of small false ribs, whereby
all lateral motion is rendered
difficult, and the crocodile is unable
to deviate suddenly from his course ;
this renders escape from them
facile, by either running round
them, or pursuing a zigzag course.
The eggs of the crocodile are as
large as those of the goose. They
inhabit fresh water, but they
cannot swallow their food under
water. The remains of crocodiles
occur in all the secondary for-
mations of England, from the lias
to the chalk inclusive, as well as
in the tertiary formations. The
fossil species are numerous, differ-
ing greatly both from each other,
and from existing species.
CHOP-OUT. A. term used by miners to
express the rising up at the
surface of one or more strata. A

U

stratum rising to the surface from
beneath another stratum is said to
crop out. Beds are said to crop-
out when they make their appear-
ance on the surface from beneath
others.

CROSS-STONE. Called also Staurolite,
and Harmotome ; it is the Para-
tomer Kuphonspath of Mohs, and
the Kreutzstein of Werner. Colours
white and grey ; occasionally it is
found with a reddish and yellowish
cast. It is composed of 47 parts
silica, 21 baryta, 15 alumina,
0'88 potash, O'lO lime, 15 water.
It occurs in small quadrangular
prisms terminated by four rhombic
planes, crossing each other. The
surface of the smaller lateral planes
is doubly plumosely streaked. It
is found in galena veins and agate
balls in the mines of Strontian, in
Argyleshire, and in other parts of
Scotland ; also at Andreasburg, in
the Hartz, and in Norway.

CEOWS'NEST. The common name
given to certain fossil cycadeous
plants of the genus Mantellia, from
an idea that they were formerly
built by crows in the fossil trees,
which have become silicified. The
largest specimens are about two
feet high and three feet in circum-
ference.

CEOWSTONE. A hard argillaceous
rock, sometimes found forming the
floor of the coal-beds : it may be
considered to be a highly indurated
variety of clunch.

CEOY'LSTONE. Crystallized cauk. In
this the crystals are small.

CEUCI'FEBOUS. (from crux and fero,
Lat.) The name given to a large
order of plants, whose petals, four
in number, are so arranged as to
resemble a cross. The radish,
cabbage, stock, &c., are cruciferous
plants.

CEU'CIFOEM. (from crux and forma,
Lat.) Cross-shaped; in the form
of a cross. In botany, polypetalous
flowers are so called, when the

C R IT

[ 116]

CRT!

petals are placsd in the form of a
cross ; this is particularly the case
in a very large order of plants,
which have four petals, so arranged
as to resemble a cross.

CRU'CIBLE. (crucilulum, Lat.) A
vessel, or melting-pot, made of
earth, so named, according to some,
from its having been formerly made
in the shape of a cross; but,
according to others, from the
metals being tortured in it by fire
to compel them to become gold.

CRU'RA. (The plural of crus, Lat.)
Applied to parts from their resem-
blance to legs ; the legs.

CRT/RAL (crural, Pr. cruralis, Lat.)
Belonging to the leg.

CRUST, (krusle, Germ, crusta, Lat.
croute, Fr. crosta, It.) Any shell,
hard coat, or external covering.
That portion of our globe which is
accessible to our inspection and
observation is called by geologists,
the earth's crust. It is this crust
which offers proper occupation to
the geologist. The greatest depth
to which he has been hitherto
able to extend his observations,
from the uppermost strata to the
lowest beds, is from eight to ten
miles ; a thickness which, compared
with the bulk of the earth, does
not exceed that of the thickness of
the paper which covers a globe a
foot in diameter. The inequalities
and crevices in the varnish applied
over the surface of such a globe
would fairly represent, and be in
proportion to, the highest mount-
ains and deepest valleys of the
world. The mean density of the
earth's mineral crust has generally
been taken at 2'5 : according to
De la Beche 2'6 would be a nearer
approximation.

" The term is not used with the
intention of conveying an opinion
that the earth consists only of a
crust, or that its centre is hollow ;
for of this we know nothing." —
Phillips.

Mr. W. Hopkins gives 800 miles
as the minimum thickness of the
solid external crust of the earth.
CRTJSTA'CEA. } (from crusta, Lat.)
CRUSTA'CEANS. ) The Crustacea pos-
sess a hard external covering, and
numerous articulated limbs; an-
tennas, and palpi; a heart, with
circulating vessels and gills, and a
nervous system. The crab, lobster,
sea urchin, shrimp, &c., are ex-
amples. Crustaceous animals pos-
sess the most solid form of the
skeleton met with in the articulated
classes. It is found in the larger
decapods to contain nearly half its
weight of carbonate of lime, and
there is also a considerable pro-
portion of phosphate of lime, with
traces of magnesia, iron, and soda.
These substances are exuded from
the surface of the true skin, along
with a tough coagulable animal
gluten, which connects all their
particles, and forms a thin varnish
on the surface. The Rev. J.
Williams suggests, — " instead of
supposing these animals to secrete
the calcareous coverings which
they inhabit, say that they emit or
secrete a gluten, to which the
calcareous particles adhere, and
thus the shells are formed." The
colouring matter is generally be-
neath this varnish, and on the
exterior surface of the calcareous
deposit, but sometimes it pervades
the whole substance of the shell. —
Dr. Rob. Grant. Professors BucTc-
land and Fyfe.

The crustaceae respire by means
of branchiae; these branchiae, some-
times situated at the bottom of the
feet, at others on the inferior ab-
dominal appendages, either form
pyramids composed of lamina in
piles, or bristled with setae ; and
in some cases consist seemingly
wholly of hairs. The crustaceae
differ from the testaceae in one most
striking point of view : lobsters,
crabs, &c., cast their shell or cover-

C R U

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CRY

ing every year, whereas the testa-
ceous animals retain theirs as long
as they exist. The shells of crus-
taceous animals appear to grow all
at once, whereas those of testaceous
animals are evidently formed by
the animal adding gradually to
them, either annually or periodi-
cally, and they are all composed of
layers.

Fossil crustaceans are by no means
rare both in the most recent, as
well as in the most ancient strata,
but they are rarely found in a state
of complete preservation. Crustacea
constituted the fourth class of the
sub-kingdom Annulosa, and is
divided into nine orders, two of
which, Trilobita and Eurypterida,
are found fossil only.

CRTTSTA'CEAN. } (crmtacee, Fr. crust-

CRUST A'CEOUS. ) aceo, It.) Shelly,
with joints. The crustaceous ani-
mals possess a hard shelly covering
divided into parts by joints, while
the testaceous have a continued un-
interrupted shell. The crustaceous
animals are the spiders of the sea.

CRUST ACITE. The name given by
some authors to any fossil crusta-
cean.

CRY'OLITE. (from Kpvo? and \jOos,
Gr.) Ice-stone. A rare mineral
of a white, brown, or red colour,
hitherto found only in Greenland,
at the arm of the sea named Arksut,
where it occurs in gneiss, associated
with iron-pyrites and galena. It
consists of fluoric acid 44, soda 32,
alumina 24.

CRYPTOGA'MIA. (from K/JVTTTO?, con-
cealed, and rya/to<?, nuptials, Gr.)
The 24th class of plants in the
LinnaBan artificial system, com-
prehending those whose fructifica-
tions are concealed, either through
minuteness, or within the fruit.
According to more modern classifi-
cation, the cryptogamia include the
thalogens, the anogens, and the
acrogens. The carboniferous era
abounded in the vascular crypto-

gamia to a degree unexampled at
the present time ; the plants belong
to species and genera now extinct,
but allied to existing types by
common principles of organization.
The numerical preponderance of
the cryptogamia in the coal is
such, that while in the present
order of nature they are to the
whole number of known plants as
one to thirty, at that epoch they
were in the proportion of twenty-
five to thirty. In the saliferous
system, about fifty species have
been ascertained, some of which
differ from any observed in the
coal measures. The class crypto-
gamia contains the ferns, mosses,
funguses, and sea- weeds : in all of
which the parts of the flowers are
either little known, or too minute
to be evident.

CRYPTOGA'MIC. } A term applied to
CRYPTOGA'MOUS. ) plants not bearing
flowers with stamens and ovarium
visible; belonging to the class
Cryptogamia. Ferns, mosses, fungi,
&c., are cryptogamic plants. In
the transition rocks, about thirteen
species of cryptogamic plants, four
of which are alga3, and the re-
mainder ferns, comprise all that is
known of the vegetable kingdom,
anterior to the carboniferous system.
CRY'STAL. (from KpvaraXXos, Gr.
crystallus, Lat. crystal, Fr. cristallo,
It. kry stall, Germ.) A crystal
may be defined as a more or less
symmetrical, geometrical solid, com-
monly bounded by plane surfaces,
which, in mineralogical language,
are termed planes, or faces. There
are many mineral, or inorganic,
substances, which assume certain
regular forms when becoming solid
from a fluid state, or when, after
being dissolved in a fluid, this
fluid is evaporated. These regular
figures are termed crystals. The
cause of a body's possessing this
power, or property, is unknown, but
it is supposed to be connected with

CRY

[118]

CRY

the form of the molecules of which
it is composed. Crystals are sym-
metrical forms. "It hasbeen said of
crystals," says the Abbe Haiiy, "that
they are the flowers of minerals; "
an observation concealing a very just
idea beneath the air of a comparison
which appears to be only ingenious.
The importance of their form will
become more evident if, in pursuing
our enquiries into the niceties of
the mechanism of structure, we
conceive all these crystals as the
assemblages of integrant molecules
perfectly resembling each other,
and subject to the laws of regular
arrangement. Thus although, by
a superficial notice of crystals, we
might adjudge them to be only the
sports of nature, a more intimate
acquaintance with them leads to
this conclusion, — that the Deity,
whose power and wisdom prescribed
the unerring laws of the planetary
motions, has also established those,
which are obeyed with the same
fidelity, by the molecules compo-
sing the various substances concealed
in the recesses of the earth. There
are six primitive forms of crystals.

1 . The regular tetrahedron, having
four equilateral triangles for its
faces.

2. The regular cube of six squares
for its faces.

3. A dodecahedron, or solid of
twelve faces, each being a rhombus.

4. The octohedron, having eight
triangles for its faces.

5. A six-sided prism.

6. A parallelepiped, or a solid of
six faces, each two of which are
parallel and equal, as a cube, a
rhomboid, &c. Prom these six
primitive forms of crystals every
variety may be supposed to be
produced, by cutting away itsangles
or edges in various manners ; or by
additions supposed to be made on
its faces. The regularity of the
figure will be influenced by the
rapidity of the evaporation, as

when the evaporation is hurried
the crystals will be confused, and
wanting in regularity; sometimes
the evaporation must be sponta-
neous, or not assisted by the addi-
tion of heat, for procuring regular
and large crystals. It must not be
supposed that every mineral crys-
tallizes naturally in, or can be cut
into, all the forms which might
be deduced from its primitive form ;
but it never occurs that the same
mineral is found assuming a form,
which cannot be shown on these
principles to be related to its
primitive, or in which primitive
it either is occasionally found, or
to which the other forms in which
it occurs may not be reduced. —
Mm. and Metals.

When bodies dissolved in any
fluid are separated by crystalliza-
tion, they are always found to
retain a part of the fluid. The
water thus retained by saline crys-
tals is called the water of crystalli-
zation. This water appears to be
essential to the transparent crys-
talline form of salts." Most salts
may be deprived of their water of
crystallization by heat ; some lose
it in the common temperature of
the atmosphere, and fall into a
pulverulent mass ; others attract
moisture so strongly that they,
from exposure to the atmosphere,
deliquesce.

CRY'STALLINE HUMOUR. } (KpvaTa\ivo<st
CRY'STALLINE LENS. j Gr. crystal-
linus, Lat.) A solid body of a
lenticular form, being a part of the
eye. It appears most absurd ever
to have given to this solid body the
name of humour. The crystalline
lens is situated behind the aqueous
humour, opposite to the pupil, and
its posterior portion is received into
a depression on the fore-part of
the vitreous humour. It has two
convex surfaces, like a common
lens, the anterior being the less
convex ; the two being formed of

CRY

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cue

segments of spheres of unequal
size.

CRYSTALIZA'TION. ] (crystallisation,

CRYSTALLIZATION. ) Fr. cristalli-
sazione, It.) A methodical ar-
rangement of the particles of
matter according to fixed laws ;
congelation into crystals.

CRYSTALLIZED QUARTZ. See Quartz.

CTENA'CANTHUS. A genus of ichthyo-
lites of the old red sandstone, two
species of which have been de-
scribed by Agassiz; C. Ornatus,
and C. Serrulatus.

CTEN'ODUS. A genus of ichthyolites
of the old red sandstone ; Aggassiz
enumerates six species.

CTENOI'DEAN. Belonging to the third
order of fishes, according to the
arrangement of M. Agassiz.

CTENOI'DIA. (from /crets, pecten, a
comb ; and e?<$os, Gr.) The third
order of fishes in the arrangement
of M. Agassiz. The ctenoidians
have their scales jagged on the
posterior margin, resembling the
teeth of a comb, from which cir-
cumstance they derive their name ;
the perch is an example. The
ctenoidians first appear at the
commencement of the cretaceous
formations, succeeding the placoi-
dean and ganoidian orders. — Prof.
BucUand.

CTENOPTI'CHIUS. A genus of icthyo •
lites of the old red sandstone.

CUBE. (from icv/3os, Gr. cubus, Lat.
cube, Fr. culo, It.) A regular
solid body consisting of six square
and equal faces, with right, and
therefore equal, angles : a die is a
small cube ; a prism contained by
six equal squares.

CUBE-ORE. A name given to the
mineral hexahedral olivenite.

CU'BIT.

1. A measure, according to Dr. Ar-
buthnot, equal to one foot nine
inches, and 888 decimal parts. —
Some.

2. That part of the arm which

extends from the elbow to the
wrist.

CU'BIZITE. A name given by Werner
to analcime.

CUBOI'DES. A bone of the foot, in
shape somewhat resembling a cube ;
it is placed at the fore and outer
part of the tarsus.

CUCULLJEA. A genus of bivalve
equilateral, deep ; hinge straight,
shells; subquadrate, equi valve, sub-
with a series of angular teeth
small near the umbones, larger,
and more oblique towards the
extremities ; the umbones are sepa-
rated by a large flat area ; the
anterior muscular impression is
bordered by a raised, sharp-edged
plate or ledge, projecting from the
side of the shell. The recent
species of Cuculla3a are few, but
the fossil are very numerous;
upwards of 30 are recorded in Mr.
Morris's catalogue from the creta-
ceous, oolitic, carboniferous, and
Devonian systems of rocks, and
additional species are known,
though not described. — Lycett.

CUCU'LLATE. } (cucullatuSyL&i.) Hood-

CUCU'LLATED ) ed ; having the shape
of a hood. Applied to leaves
when their edges meet in the
lower and expand towards the
upper part.

CUCUMERI'NA. (from cucumer, Lat.)
A species of fossil spine belonging
to the echinus, and possessing
something of the form of a cucum-
ber, whence its name is derived.
There are several varieties.

CUCU'MITES. The name given by Mr.
Bowerbank to a genus of fossil
fruits found in the London clay.
The generic characters are thus
given. " Pepo succulent, one cel-
led, many seeded. Seeds ovate,
enveloped in a thin membranous
arillus." All the parts of these
fruits so closely resemble those of
various members of the recent
genus Cucumis, both in their out-
ward form and their internal

C U L

C 120 ]

CUP

structure, that no reasonable doubt
can remain of their being true
Cucurbitacea.
CULM. (Welsh.)

1. A kind of fossil coal, of indif-
ferent quality, burning with little
flame, and emitting a disagreeable
smell.

Culm is also called stone coal.
Between culm or stone coal and
bituminous or common coal there is
no geological difference. They are
mere mineral varieties, which
occur in formations accumulated
at the same period. The coal of
the greater part of the basin of
South "Wales is stone-coal or culm.
Culm generally presents a pure,
clean, and polished fracture. Plants
common in other coal-fields occur
not only in the shale, but in the
culm itself. A numerous collection
of fossil plants from the culm
measures has been submitted to
Professor Lindley, who considers
that they all occur in other coal-
fields. They consist of various
Lepidodendra and Calamites to-
gether with Neuropteris gigantea,
Pecopterisconchitica and Pecopteris
nervosa, Iphenoyhyllum Schloth-
eimii, Stigmaria ficoides, &c., &c.
Prof. Lindley, after examining a
collection of plants from the Devon-
shire culm-measures, states, "I
have looked over them carefully,
and I do not see one single species
which might not have been met
with at Newcastle, with the ex-
ception of two round compressed
bean-like bodies, which, if of vege-
table origin, are unknown to me."

2. An herbaceous stem peculiar to
grasses, rushes, and some other
plants allied to them. Culms are
either hollow or solid, jointed or
without joints, round or triangular,
rough or smooth, hairy or downy,
and bear both leaves and flowers.

CUL'MIFEBOTJS. Containing culm ;
such are the culmiferous rocks of
Devonshire, South Wales, &c.

CUMBRIAN SYSTEM. \ The word Cum-
CU'MBRIAN. brian means

CA'MBRIAX. ) the rocks of

Cumberland ; the word Cambrian
the rocks of Wales. The Cambrian
rocks have been divided into
Upper and Lower ; the upper con-
sisting of the Coniston Flagstone,
the Coniston Limestone, and
Slates and Porphyry ; the lower
comprises the Skiddaw slates. The
Cumbrian or slate system, as
described by Professor Sedgwick,
extends over a large portion of
Cumberland, Lancashire, and West-
moreland, attaining an elevation in
some places of upwards of three
thousand feet, and affording the
splendid scenery of North Wales
and of the lakes. The strata are
of great, but unknown, thickness,
possessing a slaty character, and
nearly destitute of organic remains.
The Cumbrian, or, as it has been
also called, Grauwacke system,
includes the Plynlymmon rocks,
the Bala limestone, and the Snow-
don rocks.

CUNEIFORM. } Having the form of a
CU'NIFORM. j wedge. Three bones
of the foot have obtained the name
of cuneiform bones from their
wedge-like shape; they are situ-
ated at the fore part of the tarsus
and inner side of the os cuboides,
and are applied to each other like
the stones of an arch.
CUPANOIDES. The name given by
Mr. Bowerbank to a genus of fossil
fruits found in the London clay,
from their resemblance to the peri-
carp of Cupania Americana. Eight
species are figured and described in
his admirable work on the Fossil
Fruits and Seeds of the London
Clay.

CUPRESSINITES. The name given by
Mr. Bowerbank to a genus of fossil
fruits found in the London clay,
thirteen species of which he has
described. He says, "the fruits
forming this group are evidently

CUP

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CUT

members of the natural order
Cupressina. I have thought it
advisable to place the whole of
them together, and to term them
Cupressinites, which will allow of
our uniting under one designation,
a greater number of these evidently
very nearly allied fruits, than could
have been done had I attempted to
refer them to M. Adolphe Brong-
niart's genus Cupressites" Mr.
Bowerbank has separated this genus
into four divisions, comprising thir-
teen species ; for a description, the
reader is referred to his admirable
work on the Fossil Fruits of the
London Clay.

CU'PULE. (copula, Lat.) The cup of
the acorn and of similar fruits.

CUBL. The name given by the miners
to a variety of argillaceous lime-
stone, found in connexion with the
iron-stone. Werner gave it the
name of Dutenmergel or funnel marl.
It has been thus described by the
Rev. James Yates. " The name
evidently alludes to the convoluted
form of its distinct concretions,
each of which is either itself a
complete and regular cone, or is
wrapped round part of a cone,
which serves as the basis of its
structure. Each distinct concretion,
on being parted from the conical
surface to which it has been attach-
ed, presents on its concavity a series
of wrinkles, regularly indented, and
always parallel to the base of the
cone. The convex surface is longi-
tudinally striated. The circular
bases of the cones project a little
one beyond another, and thus give
to the external surface of the mass
the appearance of leaves folded over
one another. Hence has arisen
the conjecture, that the mineral in
question is a petrified palm, or
lotus. The fracture of this mineral
is splintery ; its colour greyish-
black. The masses, which are ex-
posed to the weather, soon acquire
externally a yellow rusty aspect,

from the combination of oxygen
with the iron which they contain.
— Geological Transactions.

CURBAGH. The name given in some
parts, as in the Isle of Man, to any
tract of peat bog.

CUBSO'KES. The sixth order of the
class aves, comprising the ostrich,
emu, bustard, &c.

CT/SPATED. (from cuspis, Lat.) Point-
ed ; terminating in a point, as the
leaves of the thistle.

CUSPIDATE. }

CUSPIDATED, j

1. A botanical term, applied to
leaves terminating in sharp ridged
spines.

2. In entomology, having a pointed
process much extended, and nearly
setiform.

CUTA'NEOTJS. (cutante, Er. cutaneo,

It.) Pertaining to the skin.
CifTiCLE. (cuticula, Lat. cuticule, Fr.)

1. The scarf-skin; the outermost
skin. The cuticle is a thin, greyish,
semi-transparent, insensible mem-
brane, which covers the skin, and
adheres to it by small vascular
filaments. It is this which is
separated by the application of
blisters.

2. In botany, the outward covering
of plants. Every plant is covered
by a cuticular expansion, analogous
to the scarf-skin that covers animal
bodies. The cuticle, or epidermis,
of plants varies in thickness, being
extremely delicate on some parts
of a flower, and very thick, hard,
and coarse on the trunks of many
trees.

CU'TIS. (Lat.) The skin, dermis,
or true skin, as distinguished from
the cuticle or scarf-skin. It lies
immediately under the corpus mu-
cosum, and gives a covering to the
whole body. It is formed of fibres
intimately interwoven, and running
in every direction, like the hairs in
the felt of a hat, and is so plentifully
supplied with nerves and blood-

CUT

[ 122 ]

C Y A

vessels, that the smallest puncture
cannot be made in any part of
it, without occasioning pain and a
discharge of blood. It is that part
of quadrupeds of which leather is
made. The cutis can be entirely
dissolved by the action of boiling
water, and consists chiefly of gelatin,
from which circumstance it is a
principal article in the manufacture
of glue.

CU'TTLE. | The sepia of Linn&us.

CU'TTLE-FISH. } A species of Cepha-
lopoda, genus Mollusca. The bone
of the sepia (which is an internal
bone, flat and broad, somewhat
resembling a sole in its appearance,)
is found, commonly, washed up on
our coasts, and when ground into
fine powder is used as pounce, and
is sometimes employed in the mak-
ing of tooth-powder. The sepia
attains to an immense size in the
seas of India and China, and it is
said that its arms, which are eight
in number, are sometimes several
fathoms long, so that it will, by
throwing them around a boat,
endanger the safety of the boat's
crew, and that it is usual to keep
on board a hatchet for the purpose
of severing them on such occasions.
Thecuttle-fishhasno external shell,
but is protected from its enemies
by a peculiar internal provision,
consisting of a bladder- shaped sac,
containing a black and viscid ink,
soluble in water, the ejection of
which, by rendering the surround-
ing water opaque, conceals and
defends the animal. The sepia has
its feet around its head, and walks
along the bottom of the sea with
its head downwards. The feet are
lined internally with little round
serrated cups, or suckers, by which
the animal both seizes its prey
and adheres to other bodies. The
mouth, which resembles a parrot's
beak, or the bill of a hawk, is
placed in the centre of the arms.
The ink of the cuttle-fish is said to

form an ingredient in the composi-
tion of Indian ink.

Professor Buckland states, in
describing the ink found in a fossil
ink-bag of the cuttle-fish, " So
completely are the characters and
qualities of the ink retained in its
fossil state, that when, in 1826, I
submitted a portion of it to my
friend Sir Francis Chantrey, re-
questing him to try its power as a
pigment, and he had a drawing
prepared with a triturated portion
of this fossil substance, the draw-
ing was shown to a celebrated
painter, without any information
as to its origin, and he immediately
pronounced it to be tinted with
sepia of excellent quality."

The common sepia used in draw-
ing is from the ink-bag of an
oriental species of cuttle-fish.

CY'ANITE. (from /oWos, Gr. color
c&ruleus, or sky-coloured.) Called
also Kyanite, and by Saussure,
Sappare, is a mineral of a grey,
blue, and blueish-green colour. It
occurs regularly crystallized, as
well as massive and disseminated ;
the form of the primitive crystal is
an oblique prism. Its texture is
foliated; laminaa long; fragments
splintery. It feels some what greasy.
Before the blow-pipe it becomes
almost perfectly white, but it does
not melt. Its constituent parts
are, alumina 64'30, silica 34'33,
with a trace of oxide of iron and a
very small portion of lime.

CY'ANOGEN". (from KiWos, blue
colour, and ^ewdw, to produce,
Gr.) A colourless gas which burns
with a purple-blue flame. It is the
essential ingredient in Prussian
Blue.

CYA'THIFOBM. (from cyathus and
forma, Lat.) In the form of a cup,
or drinking-vessel ; cup-shaped.

CYATHOCBIHI'TES. (from icvaOos, a
cup, and Kplvov, a lily, Gr.) Cup-
like, lily-shaped animal. The name

C Y A

[ 123 ]

CYC

assigned by Miller to a genus of
crinoidea. There are many species.
Miller thus describes the generic
characters. " A crinoidal animal,
with a round or pentagonal column
formed of numerous joints, having
side arms proceeding irregularly
from it. On the summit adheres a
saucer- shaped pelvis of fine pieces,
on which are placed in successive
series, five costal plates, five sca-
pulaa, and an intersecting plate.
From each scapula proceeds one
arm, having two hands. The
several species of Cyathocrinites
occur in the mountain limestone
and transition strata; no recent
specimen has hitherto been dis-
covered. One species, C. rugosus,
has been mistaken for a species of
Marsupite, but the marsupite pos-
sessed no column, whereas the
Cyathocrinite has one.

CYATHOPHY'LLOTJS. (from waOos, and
0vA\ov, Gr.) Having cup-shaped
leaves.

CYCA'DEA. (from /cvica?, cycas, Gr.)
A genus of plants. The cycader>
hold an intermediate place between
the palms, ferns, and coniferse.
" That curious tribe," says Lindley,
that stands on the very limits of
Monocotyledons and Dicotyledons,
and of flowering and flowerless
shrubs.'* Some species are very
short, as the zamia ; others attain
a height of thirty feet and upwards.
This beautiful family of plants in
their external habit resemble that
of palms, whilst their internal
structure approximates to that of
conifers. The cycadese are natives
of warm climates, mostly tropical,
though some are found at the Cape
of Good Hope. Leaves of cycadese
are of frequent occurrence in the
shale of the oolitic formation near
Scarborough, and they have been
foundin the Stonesfield slate. Cyca-
dese have been found in the coal for-
mation of Bohemia. The trunk of
the cycadese has no true bark, but

it is surronnded by a dense case,
composed of persistent scales,
which have formed the bases of
fallen leaves ; these, together with
other abortive scales, constitute a
compact covering that supplies the
place of bark. The prevalence of
cycadese gives a distinctive charac-
ter to the flora of the upper
secondary formations. The stems
found in the Isle of Portland, and
the leaves and fruits in the oolitic
formations of Yorkshire, show con-
siderable analogy to the existing
forms of the tribe at the Cape of
Good Hope, in India, and Aus-
tralia.

CY'CADITES. A name applied to some
fossil species of cycas. Our fossil
cycadites are closely allied by many
remarkable characters of structure
to existing cycadese. — Bucldand.
CYCA'DEOIDEJB. The name given by
Prof. Buckland to the petrified
remains of certain plants allied to
the natural family of Cycadeae, and
resembling the existing genera
Zamia and Cycas, though still
distinct from both. These fossil
remains were obtained from the
Isle of Portland ; they are now
converted into silex, their substance
varying from a coarse granular
chert to imperfect calcedony :
everything seems to favour the
supposition, that the plants thus
petrified, like those of the analogous
recent genera, were the inhabitants
of a climate much warmer than
that of this country at the present
day. M. Adolphe Brongniart has
assigned the name Mantel] ia to this
new genus.

CY'CAS. (/cv/cae, Gr.) The term Cycas
was first applied by Theophrastus
to a palm tree ; it is now used to
distinguish a natural order of vege-
tables, introduced by botanists and
phytologists as a connecting link
between the ferns and the palms.
A genus of plants belonging to the
first natural order Palmse, according

CYC

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C Y P

to the first arrangement of Lin-
naeus, but subsequently placed
among the ferns.

CY'CLAS. (pi. cyclades.) A genus of
lacustrines, or fresh- water bivalves.
The calciferous grit near Hastings
is full of cyclades, and several
species of cyclas occur, in myriads,
in the shales and clays of the
"Wealden formation. — Mantell.

The clycas is an ovato-transverse
bivalve, not inflected on the fore
part ; the hinge with three hinge-
teeth and two lateral teeth, com-
pressed and rather remote. — Par-
kinson.

"While the clycas of Europe is
described as small, thin, and
horny, abounding in ditches, ponds,
and slow streams, that of Asia is
stated to be very large. The cyclas
is viviparous.

CY'CLE. (from KVK\OS, Gr. cycle, Fr.
ciclo, It.) A round of years which
go on from first to last, and then
return to the same order as before ;
a space in which the same revo-
lutions begin again.
CY'CLOTD. (from icv/cXos, and e$>os,
Gr. cyclo'ide, Fr.) A geometrical
curve ; a figure made by the upper
end of the diameter of a circle,
turning about a right line.
CYCLOI'DIANS. (from KV/C\O?, Gr.)
The fourth order of fishes, according
to the arrangement of M. Agassiz.
Families of thii order have their
scales smooth and simple at their
margin, and often ornamented with
various figures at the upper surface.
The salmon and herring are
examples.

CYCLOI'DEAN. Belonging to the fourth
order of fishes, according io the
arrangement of M. Agassiz. The
cycloidean and ctenoidean orders
succeeded the placoidean and ganoi-
dean.

CY'CLOMTE. (from KVK\OS and \i'0os,
Gr.) Another name for madrepore.
CY'CXOPITE. A sort of zeolite, resem-
bling analcime, found in the pores

of the lava of Etna. The pores of
the lava are sometimes coated, or
entirely filled, with carbonate of
lime, and with a zeolite resembling
analcime, which has been called
cyclopite. — Lyell, Principles of Geo-
logy.

CYCLOP'TERIS. A genus of plants of
the coal series.

CY'LINDER. (icvXivdpos, Gr. cylindrus,
Lat. cylindre, Fr. cilindro, It.) A
solid formed by the revolution of
a rectangular parallelogram about
one of its sides, so that it is ex-
tended in length equally round,
and its ends or extremities are
equal circles.

CYLI'NDBOID. A solid, in many
respects resembling a cylinder, but
having elliptical instead of circular
extremities, yet parallel and equal.

CYLINDBICO'DON. The name given to
a genus of oviparous quadrupeds.

Under this name, Dr. Jaeger, of
Stutgard, has described the remains
of a fossil reptile, of which almost
the entire upper jaw, with the
teeth, has been discovered by him
in the Keuper formation of Ger-
many, near Wurtemburg.

CYME, (cyma, Lat. /a)/*a, Gr.)

1. A form of inflorescence, the
general appearance of which re-
sembles an umbel, and agrees with
it in this respect, that its common
stalks all spring from one centre ;
but differs in having those stalks
alternately and variously divided.
The oleander and elder are ex-
amples.

2. A sprout, as of a cabbage.
CYPERA'CE^. A tribe of plants

answering to the English sedges;
they are distinguished from grasses
by their stems being solid and
generally triangular, instead of
being hollow and round. Together
with graminea3, they constitute what
writers on botanical geography often
call glumacese. — Lyell, Principles of
Geology.

GYM

[ 125 ] C Y B,

CY'MOPHANE. A name given by Haiiy
to the chrysoberyl, which see.

CYMO'S^. Plants whose inflorescence
is disposed in the form of a cyme ;
the sixty-third natural order of
Linnaeus.

CYPB^A. (The cowry.) Animal a
slug; shell univalve, oval, or oblong,
involute, smooth, obtuse at each
end ; aperture long, narrow, ex-
tending the whole length of the
shell, and dentated on each side.
The mantle sufficiently ample to
fold over and envelope the shell,
which at a certain age it covers
with a layer of another colour.
The genus cypraea consists of beau-
tifully coloured shells very highly
polished. They live in sand at the
bottom of the ocean ; the animal is
provided with a membrane, which
it throws over its shell, which not
only preserves the fine polish, but
prevents testaceae from fixing on it.
One hundred and twenty species
have been described, one only of
which belongs to our seas; the
rest are all tropical. In some parts
the shell of this animal is used in
the place of money, and passes
current. By some it is thought
that the cyprsea casts its shell
annually.

CYPKI'FEBOTJS. Containing shells of
the genus Cypris. Entire layers of
stone are sometimes composed of
the consolidated remains of the
cypris; these shells occur in the
Hastings sand and sandstone, in
the Sussex marble, and in the
Purbeck limestone. The cypris
contains -many species of a genus
of crustaceous animalcules formerly
called monoculus, from its single
eye.

CY'PEIS. A genus of animals, en-
closed within two flat valves, like
those of a bivalve shell, inhabiting
the waters of lakes and marshes.
The cypris throws off its integu-
ments every year, which the con-
chiferous molluscs do not. This

circumstance serves to explain the
presence in certain places of the
countless myriads of the shells of
the cypris. The cypris is a micro-
scopic crustacean, with which cer-
tain clay beds of the Wealden are
so abundantly charged, that the
surfaces of many laminae, into which
this clay is easily divided, are often
entirely covered with them, as with
small seeds. The Sussex marble
abounds in the shells of the cypris.

The cypris has two antennae ter-
minated by a pencil of hairs ; one
eye and four legs ; the head con-
cealed, and the tail small. It
inhabits fresh-water only. Three
or four species of cypris have been
discovered in the Wealden group,
but the cypris taba is the most
abundant.

CY'PETNA. Anequivalve, inequilateral,
sub-orbicular, marine bivalve; liv-
ing in sandy mud. Fossil species
occur in the tertiary deposits.

CY'PBINE. Cupreous idocrase. See
Idocrase and Vesuvian.

CYPEICA'BDIA. A genus of bivalve
shells belong to the family Cardi-
acea of Lamarck. Fourteen species
are established as occuring in our
English deposits, namely, five in
the Silurian, three in the Devonian,
four in the carboniferous, one in
the oolitic, and one in the tertiary
system.

CYBE'NA. A genus of small bivalve
fluviatile shells, eight species of
which are recorded as found in the
tertiary series of rocks.

CYETO'CEEAS. (from Kvp-ros, carved,
and Kepas, a horn, Gr.) A genus of
fossil chambered shells established
by Goldfuss, the form is bent,
arched or partially convoluted, the
free end being sometimes elongated
and straight, the siphuncle is sub-
dorsal or marginal, the aperture
nearly orbicular. Cyrtoceras has
been found only in the Silurian
and Devonian systems of rocks; 13

C Y S

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D A V

English species are recorded in Mr.
Morris's catalogue, one only of
which, the C. leeve, belongs to the
Silurian system. — Lycett.

CYSTIDEA. The seventh order of
the class Echinodermata. All the
genera of this class are extinct,
and found fossil only.

CYSTIPHYLLUM. (from /CVST/.S, vesica,
and 0vXXoi/, folium, Gr.) A genus
of corals found in the Silurian
rocks, and thus named by Mr.
Lonsdale. Externally, they are
striated; internally, composed of
small bladder-like cells. From
this internal structure, and from
the absence of a distinct centre,

Mr. Lonsdale has named the genus,
separating it from the Cyathophylla
of Goldfuss.

CYTHER^J'A. A marine bivalve; equi-
valve, lenticular, oval ; hinge with
two cardinal teeth ; one anterior
lateral tooth in each valve, which
distinguishes this genus from Yenus.
It is found in depths of the ocean
varying to fifty fathoms, in mud
and coarse sands. Several species
have been found fossil in the ter-
tiary deposits. Cytheraea nitidula
is mentioned by Dr. Mantell as
occurring in the London clay, and
cythersea convexa in the Plastic
clay.

D

DACHSTEIN BEDS. Beds of the triassic
period. The Dachstein beds attain
in some parts of Germany a thick-
ness of 2,000 feet, they are of white
or greyish limestone. Below, these
beds are unfossiliferous, but above,
they contain beds made up of corals.

DACTYLOPO'BA. A genus of lapideous
free polypifers, of a cylindrically
elevated form, with a perforation
in the narrower extremity. The
surface reticulated with rhomboidal
meshes, the network itself porous.

DA'OTJEITE. The siberite of Lermina.
A variety of the red shorl of Siberia,
called also rubellite. This stone is
found in Siberia mixed with white
quartz. It is composed of silica
56, alumina 36, with some oxide
of manganese, and oxide of iron.
Daourite is another term for ru-
bellite; it is in fact a variety of
tourmaline, of a red colour. It
has obtained a variety of names,
as, rubellite, siberite, daourite,
tourmaline, apyre, red schorl of
Siberia, &c. See Tourmaline.

DA'SYPTTS. (SaavTrovs, from £a<rt>9 and
irovs, Gr.) The armadillo, which
seee

DASYU'KTJS. An animal of the mar-
supial order. The dasyurus is said
to be the largest of the carnivorous
marsupial animals. The head of a
species of dasyurus has been dis-
covered in the Eocene freshwater
limestone of Auvergne.

Dasyurus ursinus is a very fero-
cious creature about the size of a
badger, its actions and habits much
resemble those of a bear.

DA'THOLITE. j The Dystom-spath of

DA'TOLITE. ) Mohs. A sort of
spar-stone; the siliceous borate of
lime. According to Menil, it is a
combination of silica 38f50, lime
35-60, boracic acid 21-30, water
4' 60. Its varieties are named
Botryolite, Earthy Botryoidal Da-
tolite, and Common Datolite. It
has been found principally in
Norway, in beds of magnetic iron-
ore.

DA'VYNE. A earthy mineral, de-

DEB

[127]

DEC

scribed by Monticelli and Covelli
in their Podromo della Mineralogia
Yesuviana, and by them named
after Sir H. Davy. It is of a
white, or yellowish colour ; trans-
parent; translucent, or opaque.
Specific gravity 2-4 ; hardness 5 to
5-5.

DEBA'CLE. (Debacle, Fr. Amas de
glagons qui arrivent avec impttuosite,
dans un dfyel sulit, apr&s qu'une
riviere a eU prise long-temps.} A
violent torrent or rush of waters,
which, overcoming all opposing
barriers, carries with it stones,
rocks, and other fragments, spread-
ing them in all directions.

DEBOT/CHE. (debouche^ Fr. L'ex-
tr6mit& (Fun defile, d'un col de
montagnes.) The outlet of a narrow
pass.

DEBE'IS. (debris, "Fi.) The fragments
of rocks ; the ruins of strata ; the
rubbish, sand, grit, &c., brought
down by torrents.

DECAHE'DRAL. (from Seica, and e£pa,
Gr.) Having ten sides.

DECAHE'DBON-. A figure which hath
ten sides.

DECA'NDEIA. (from £e/ca, and avrjp,
Gr. ) A class of plants characterized
by having ten stamens ; it includes
cassia, ruta, saxifraga, &c.

DECA'NDEIAN. Belonging to the class
Decandria ; having ten stamens.

DECAPHYLLOUS. (from SeW, and
0vXXoi/, Gr.) A calyx which hath
ten leaves.

DECA'PODA. (from &•'*«, ten, and n-ovs,
foot.) The first order of Crustacea.
Having the antenniferous region of
head confluent with the thorax.
This order includes lobster, crab,
craw-fish, shrimp, &c.

DECA'POPAL. Belonging to the order
Decapoda; having ten feet. Sy-
nonymous with decempedal.

DECE'MFID. (from decetn and fasus,
Lat.) Ten-cleft; in botany, a
term for a calyx cleft, or divided,
into ten parts.

DECEMLO'CVLAB. (from decem and

loculus, Lat.) Ten-celled; in bota-
ny, an epithet for a pericarp
divided into ten loculi or cells.
DECI'DUOTTS. (deciduus, Lat.)

1. In botany, falling off; plants
which lose their leaves in autumn
are called deciduous ; applied also
to stipules falling in the autumn ;
to calcyces falling soon after the
expansion of the corolla; and to
the corolla when falling with the
stamens.

2. In conchology, to shells having
a tendency in the apex of the spire
to fall off; to crustaceans, annually
casting their shells.

DECOMPOSE, (decomposer, Fr. Reduire
un corps d ses principes, ou stparer
les parties dont il est compost.) To
resolve a body into its constituent
elements ; to overcome the power
of affinity, and thereby to separate
elementary particles.

DE'COMPOUND. Doubly compound.
Leaves are so called when the
petioles, instead of bearing leaflets,
branch out into other petioles to
which the leaflets are attached.

DE'CREMENT. (decrementum, Lat.)
Gradual waste, or wearing away,
as of rocks by the action of water ;
gradual diminution. In mineral-
ogy, decrement is considered as of
two kinds, single and compound.
When in crystals the planes de-
crease equally to a point, they are
said to arise from simple decrement ;
but when, as in the pentagonal
dodecahedron, the planes do not
decrease equally on all sides, the
decrement is termed compound.

DECEE'SCENT. (decrescens, Lat.) Gra-
dually becoming less.

DECU'BEENT. (from decurro, Lat.)
Running downwards. Applied to
sessile leaves when the base runs
down the stem and forms a border
or wing; applied also to stipules
when extending downwards along
the stem. In some plants, as in
some of the thistles, the margins of
sessile leaves run down on each

DEC

[ 128 ]

DEN

side of the stem, so as to appear to
be of one piece with it ; these
leaves are called decurrent.

DECTT'BSIVELY PINNATE. Applied to
leaves having their leaflets decur-
rent, or running along the petiole.

DECTJ'SSATE. (decusso, Lat.) To in-
tersect at acute angles ; to cross
each other at right angles. Ap-
plied to branches growing in pairs,
and alternately crossing each other
at right angles ; applied also to
leaves alternately opposite. In
conchology, applied to stria3, cros-
sing or intersecting each other at
acute angles.

DEFLE'XED. (deflexus, Lat.) In
entomology, having the sharp edge
bent downwards.

DIGEADATION. (degradation, Fr. H
signifie ddptrissement, etat de dSca-
denoe, de ruine. This term is used
by geologists to signify the lessen-
ing or wearing away of rocks,
strata, &c., by the action of water,
or other causes.

DEHI/SCE»TT. (dehiscent, Lat.) In
botany, fruits which open when
ripe, so as to enable the seeds
to escape, are termed dehiscent.
Gaping; opening.

DELPHI'NULA. (from delphinus, Lat.)
A turbinated, subdiscoidal, um-
bilicated univalve. The aperture
round and pearly; operculum horny.
The delphinula creeps on rocks and
sea-weeds. This genus is formed
of shells formerly included by
Linnaeus in his genus Turbo. La-
marck places delphinula in the
family Scalariana. The fossil del-
phinula occurs in the tertiary
deposits; it is also recent.

DE'LTA. A term applied by geologists
to the alluvial deposits formed at
the mouths of rivers. It has ob-
tained its name from a supposed
resemblance to the Greek letter A.
Deltas are occasionally of immense
size, and they are divided into lacus-
trine, mediterranean, and oceanic,
the first being those formed in lakes,

as the delta at the mouth of the
Rhone, at the upper end of the
lake of Geneva; the second, or
mediterranean, are those formed in
inland seas, as that at the mouth
of the Rhone, where it enters
the Mediterranean; the third, or
oceanic, are those formed on the
borders of the ocean, as the delta
of the Ganges.

DELTHY'EIS LIMESTONE. A shaly
limestone, met with in the Heidel-
berg group.

DE'LTOID. (from delta, the fourth
letter of the Greek alphabet.) The
name of a muscle of the shoulder,
from its supposed resemblance to
the Greek letter A ; triangular.

DE'NDRACHATE. (from SevSpov and
a^ar^s, Gr.) An agate with delin-
eations of trees, ferns, moss, &c.
Some of these are exceedingly
beautiful, and are so elegantly
depicted that they have been erro-
neously taken for real plants, whence
their name. These pebbles are
found abundantly on the shore from
Bognor to Brighton, and, when cut
and polished, are made into very
beautiful necklaces, brooches, snuff
boxes, &c., &c.

DE'NDRITE. (Sevtyi™, Gr.) The
same as dendrachate.

DENDK'ITE AGATE. A species of agate,
thus named from its containing in
its interior brown, reddish-brown,
or blackish delineations of leafless
trees, shruhs, &c. For a descrip-
tion see Mocha stone.

DENDEI'TICAL. Containing the re-
semblance of trees, ferns, or mosses.

DENDR'ODUS. In the transverse
section of these reptile teeth the
cancelli are found to radiate from
the open centre towards the cir-
cumference, like the spokes of a
wheel from the nave ; and each spoke
seems as if it had sprouted into
branch and blossom, presenting the
appearance of a well-trained wall-
tree: hence the generic name
Dendrodus, assigned by Professor

DEN

L 129]

DEN

Owen. The name Dendrodus,
appears to have been supplanted by
that of Cricodus. The Dendrodus
is an icthyolite of the old red sand-
stone, of which six species have
been particularized by Agassiz.

DE'NDKOITE. A fossil resembling the
branch of a tree.

DE'NDEOLITE. (from Sevtyov and
\i0os, Gr.) Fossil wood; the
fossil branch of a tree.

DE'NSITT. (densitas, Lat. densitt, Fr.
densitd,, It.) Closeness; compact-
ness ; that property directly oppo-
site to rarity, whereby bodies con-
tain such a "quantity of matter in
such a bulk. The densities of
bodies are proportional to their
masses, divided by their volumes.
Hence if the sun and planets be
assumed to be spheres, their volumes
will be as the cubes of their diame-
ters. The strata of the terrestrial
spheroid are not only concentric
and elliptical, but the lunar in-
equalities show that they increase
in density from the surface of the
earth to its centre.

The absolute density of, or the
quantity of matter contained in,
the earth, compared with an equal
bulk of any known substance, may
be nearly determined by the attrac-
tive force which any given mass of
matter exerts upon a plummet, when
suspended in its vicinity, to draw
it from a vertical line. By this
method it has been found that the
mean densisty of the earth is about
five times greater than that of water,
or nearly twice the average density
of the rocks and stones on the sur-
face. The mean density of the
ocean is only about one-fifth part
of the mean density of the earth.
More recent observations, by the
astronomer royal, on the pendulum
at the surface and at the bottom
of deep mines, give a mean of
6-809 for the earth's specific
gravity, while those made by the

ordnance survey, on the deflection
of the plumb-line, give it as 5'14.
DE'NTAL. | (from dens, Lat.) A
DENTA'LITTM. ) shell-fish belonging,
according to Linnaeus, to the class
Vermes, order Testaca. The shell
consists of one tubulous arcuated
cone, open at both ends. There
are many species, distinguished by
the angles, striae, &o., of their shells.
The observations of Deshayes
lead to the conclusion that the
genus Dentalium approaches very
closely to the molluscs, if, indeed,
it does not belong to them.
The dentalia are found in deep
water, frequently near the shore,
inhabiting the ocean only; they
are solitary. Captain Yidal drew
up dentalia from the mud of
Galway Bay from a depth of 240
fathoms. The animal is a terebella.
The shells are known commonly
by the name of tooth-shells, or
sea teeth. Twenty-two species
have been described, seven of
which inhabit our coasts.
DE'NTALITE. ] (from dens, a tooth,
DE'KTALITHE. ) and \iOos, a stone.)
A fossil dentalium found in the
tertiary formations, in the gait and
in the lower green sand. Of these
there are many species ; as the Den-
talium planum, D. striatum, D. el-
lipticum, D. decussatum, &c. See
Ditrupa.

DENTA'TA. A name given to the
second vertebra of the spinal
column, from a tooth-like process
which it possesses.

DE'NTATE. } (dentatus, Lat.) Indent-
DE'NTATED. ) ed; jagged; notched;
toothed. In botany, leaves are
called dentated, when the border
is beset with horizontal projecting
points or teeth, with rather a
distant space between each, and of
the same consistence as the sub-
stance of the leaf itself : applied
also to stipules having spreading
teeth about the margin, remote
from each other.

DEN

[ 130]

D E IT

DE'NTATUEE. Pertaining to the teeth
of an animal, to their structure
and character.

DE'NTED. (dente, Er. decoupe en
pointes serrees Us unes contre les
autres.) Notched; indented.

DB'NTICLE. } (denticule, Pr.) A small

DE'NTICULE. j tooth or projecting
point.

DE'NTILE. A small tooth, as that of
a saw : a term used in conchology.

DENTICULATED. (denticulatus, Lat.)
Set with small teeth, as in the
area.

DE'NTOID. (from dens and e?£o§, Gr.)
Of the shape, or form, of a tooth.

DENITBA'TION. (denudatio, Lat. denu-
dation, Pr.) The laying bare ; the
act of divesting of its covering;
the uncovering of strata by the
washing away of their covering ;
the stripping off the superstrata.

DEO'XYDATE. | To reduce from the

DEO'XYDIZE. ) state of an oxyd by
depriving it of its oxygen.

DEO'XIDIZED. j Deprived of oxygen ;

DEO'XTDIZED. f disunited, or sepa-

DEO'XTDATED. ( rated from the oxy-

DEO'XYDATED. / gen with which it
was previously joined.

DEPO'SIT. Matter laid or thrown
down; that which having been
suspended or carried along in a
medium lighter than itself at
length subsides, as mud, gravel,
stones, detritus, organic remains,
&c.

DEPEE'SSED. (depressus, Lat.) Pressed
down ; low ; shallow ; flat. In
botany, leaves are called depressed
when flattened vertically : radical
leaves are thus called when they
are pressed close to the ground.

DEPEE'SSION. (depressio, Lat. depres-
sion, Pr. depressions, It.) The
sinking, or falling in, of a surface.

DEPEE'SSOE. The name given to
such muscles as have the power of
depressing, as the depressor anguli
oris, &c.

DEPUEA'TION. (depuration, Pr. depu-
ramdne, It. depuratio, Lat.) The

action of freeing from impurities,
of cleansing.

DEEA'CINATE. (deraciner, Pr. tirer de
terre, arr etcher de terre un arlre.)
To tear up by the roots ; to
extirpate.

DE'EBYSHIEE SPAE. This beautiful
substance is fluate of lime, a com-
bination of calcareous earth with
fluoric acid ; it occurs in nodular
masses, and in crystals. It is
found in great beauty and abun-
dance in Derbyshire, whence it has
obtained its nama, but it is also
plentiful in other parts of England.
It is also called flour-spar and blue-
John, which latter see.

DE'BMAL. (from Sep^a, Gr.) Be-
longing to the skin; composed of
skin. Thus we read of the dermal
fringe of the iguana ; the dermal
bones of the hylaaosaurus.

DE'EMA. ] (ZePfia, Gr.) The true

DE'EMIS. j skin, as distinguished
from the cuticle, epidermis, or
scarf-skin.

DE'EMOID. (from Seppa., and e^o?,
Gr.) Belonging to the skin; re-
sembling the skin.

DE'SMINE. A mineral found in the
lava of extinct volcanoes accom-
panying spinellane ; its form of
crystallization is in small silken
tufts.

DETEI'TION. The act of wearing away.

DETEI'TAL. Composed of detritus;
consisting of the disintegrated ma-
terials of rocks.

DETEI'TTJS. (Lat.) The worn off,
or rubbed off, materials of rocks.
"Beneath the whole series of
stratified rocks," says Professor
Buckland, " that appear on the
surface of the globe, there probably
exists a foundation of unstratified
crystalline rocks, bearing an ir-
regular surface, from the detritus
of which the materials of stratified
rocks have in great measure been
derived."

DETJTO'XIDE. ) (from £e^Te/>os,Gr. and

DEUTO'XYDE. j oxyd.} Called also

D E V

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D E X

Binoxide. A substance in the
second degree of oxidation, or con-
taining two prime proportions of
oxygen : a protoxide is in the first
or smallest degree ; a tritoxide
denotes a third proportion, and a
peroxide has the greatest degree of
oxidation.

DEVE'XITY. (devexitas, Lat.) De-
clivity ; a bending downwards.

DEVOLUTION, (devolutio, Lat. dtvofa-
tion, Fr. devoluzidne, It.) The act
of rolling down, as the removal of
earth or strata into a valley.

DEVO'LVE. (devolve, Lat.) To roll
down, as " every headlong stream
devolves its winding waters to the
main." In this sense, however,
the word is not modernly used:
in its common acceptation, at the
present day, it signifies to pass
by succession from one person to
another.

DEVONIAN SYSTEM. A term assigned
by Sir R. Murchison to a series of
strata largely developed in Devon-
shire and Cornwall, and belonging
to the Old Red Sandstone. "Though
the term Old Red Sandstone, when
designating great groups of rocks
like the Cornish killas and Devon-
ian slates, should involve no error
of classification, still it would,
mineralogicall y, be most inappro-
priate. We purpose therefore, for
the future, to designate these groups
collectively by the name Devonian
system, as involving no hypothesis,
and being agreeable to analogy.
Thus the terms Carboniferous sys-
tem, Devonian system, Silurian
system, and Cambrian system, will
represent a vast and apparently un-
interrupted sequence of deposits."
— Sedgwick and Murchison.

DEW. A considerable refrigeration
of the surface of the ground below
the temperature of the air resting
upon it, amounting to 10 or 20
degrees, occurs every calm and
clear night, and is caused by the
radiation of heat from the earth

into space. On becoming colder
than the air above, the ground will
condense the moisture of the air in
contact with it, and be covered
with dew. The air, however clear,
is never destitute of watery
vapour, and the quantity of vapour
which air can retain depends on its
temperature ; air at 32° being
capable of retaining 1-1 50th of its
volume of vapour, while at 52° it
can retain as much as l-86th.
That the deposition of dew depends
entirely on radiation is fully estab-
lished by the following circum-
stances : 1st. It is on clear and
calm nights only that dew is
observed to fall : when the sky is
overcast with clouds, no dew falls,
for then the heat which radiates
from the earth is returned by the
clouds above, and prevented from
radiating into space, so that the
ground does not become colder than
the air. 2nd. The slightest screen,
such as a cambric handkerchief,
stretched between pins, at the
height of several inches from the
ground, is sufficient to protect the
objects below it from this chilling
effect of radiation, and prevent the
formation of dew or hoar-frost upon
them. Plants derive a great part
of their nourishment from this
source; and as each possesses a
power of radiation peculiar to itself,
they are capable of procuring a
sufficient supply for their wants.
DEW-LAP. The loose skin which
hangs down under the throat of
the cow and other animals, and
thus called from its licking or
lapping the dew when grazing.
DEX'TER. ) (Latin.) The right, as
DE'XTEAL. ) opposed to the left.
In conchology, shells are divided
into dextral and sinistral. The
more common turn of shells is with
the apparent motion of the sun, or
as the index or hand of a clock
moves. On the contrary, a re-
versed, or sinistral, shell, when

D I A

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D I A

placed in a perpendicular position,
has its spriral volutions in an oppo-
site direction to the motion of the
index of a clock, and resembles
what is called a sinistral, or left-
handed screw. The sinistral shells
are sometimes termed heteroclitical,
and heterostrophe shells. There
has been considerable confusion
amongst conchological writers in
describing the position in which
shells should be held, to ascertain
the right from the left sidfc, &c.
Perhaps, the most simple plan is,
to place the apex of any spiral
shell towards the eye with the
mouth downwards ; dextral shells
will then be found to have their
aperture on the right side of the
axis', sinistral shells, on the con-
trary, will have theirs on the left
of the axit.

DI'ABASE. A crystalline granular,
sometimes porphyritic, or even
a slaty, mixture of augite and
labradorite or oligoclase, mostly
with some chlorite. — Jukes.

DIADE'LPHIA. (from £/? and a

Gr.) The seventeeth class of
plants in the artificial system of
Linnaeus. The stamens are united
into two parcels at the base. This
class has papilionaceous flowers
and leguminous fruits. Familiar
specimens will be found in the
garden pea, bean, &c. &c.

DIADF/LPHOTJS. Having its stamens
united into two parcels at the
base ; belonging to the class Dia-
delphia.

DTA'GONAL. (StaryoWos, Gr. db angulo
ad angulum perductm : diagonius,
Lat. diagonal, Fr. diagondle, It.)
A line reaching from one angle to
another, so as to divide a parallello-
gram into equal parts. Diagonals
principally belong to quadrilateral
figures.

DIA'GONALLY. (diagonalement, Fr.
diagonalemente, It.) In a diagonal
direction.

Di' ALL AGE. Schiller spar ; a variety
of augite or crystallized serpentine.
The colour of diallage is dark-
green.

DI'AMOND. (diamant, Fr. diamante,
It. aSapa*}, Gr. adamas, Lat.) The
hardest and most valuable of all
the precious stones. Some min-
eralogists form a family of the
various sorts of diamond, under
the title Diamond Family, placing
it in the class of earthy minerals :
others place the diamond amongst

~ those minerals termed combustible,
of which the basis is either sulphur
or carbon. Strange as it may
appear, diamond consists of pure
carbon. If the best charcoal be
burnt in oxygen, carbonic acid gas
is formed, the weight of which is
nearly equal to that of the charcoal
and the oxygen, there being a
small residuum of earthy ashes
left after the combustion ; but if,
in like manner, a diamond be
burnt in oxygen, carbonic acid gas
is equally the result, though, in
the latter case, there is no residuum,
and the carbonic acid gas obtained
is precisely equal in weight to the
two elements, the oxygen and the
diamond. Why, or how, it is that
the same elementary substance can,
with little or no addition, form
two such excessively dissimilar
bodies as diamond and charcoal, —
the former the hardest and clearest
body in nature, the latter a mere
black soft, brittle mass, — is a
mystery beyond our finite powers
to comprehend. The primitive
crystal of the diamond is the
regular octahedron, each triangular
facet of which is sometimes re-
placed by six secondary triangles
bounded by curved lines ; so that
the crystal becomes spheroidal,
with 48 facets. When rubbed, the
diamond shews positive electricity.
It reflects all the light falling on
its posterior surface at an angle of
incidence greater than 24° 13',

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D I A

whence its great brilliancy is
derived. Its lustre is brilliant
adamantine ; fracture conch oidal.
Neither acids nor alkalies produce
any effect upon it. The diamond
is hard in the highest degree, and
scratches all other known minerals.
Specific gravity from 3 '5 to 3*6.
It burns when heated to 14° of
"Wedgwood's pyrometer, a point
just below that at which silver
fuses. It is the natural edge of
the diamond only that has the
property of cutting glass, all arti-
ficially formed edges will only tear
or scratch it. Diamonds are found
of nearly every shade of colour ;
those which are colourless are
deemed the most valuable. The
weight and value of diamonds is
estimated in carats, one carat being
equal to four grains, and the
difference between the price of one
diamond and another, all other
matters being equal, is as the
squares of their respective weights,
thus the value of three diamonds of
one, two and three carats weight,
is as one, four, and nine. To
estimate the value of a wrought
diamond, ascertain its weight in
carats, multiply this by two, then
multiply this product into itself,
and lastly multiply this latter sum
by £2. Thus a wrought diamond
of one carat is worth £8, one of
two carats is worth £32, one of
three carats £72, one of four carats
£128; and so on. Zireon is some-
times substituted for diamond.
The largest diamond known is
said to be that which belonged
to the late Emperor of the Brazils ;
it is uncut, and weighs 1680 carats,
or 11 ounces 96 grains. This
magnificent gem would be worth,
supposing the table of rates to be
applicable to stones above a certain
size, £5,645,000, but the highest
price that has ever been given for
a single diamond is £150,000. A
diamond in the possession of the

Great Mogul is of the size of half a
hen's egg. The Pitt diamond,
now the property of the king of the
French, was sold for £100,000.; it
weighs 136 carats, or nearly one
ounce.

Brazil and Hindostan are the
localities where diamonds are prin-
cipally obtained. Those of Brazil
are generally less large, but of the
finest water. Diamonds are cut
and manufactured into what are
termed brilliants and rose-diamonds,
The former being mostly made out
of octahedral crystals, the latter
from the spheroidal varieties. In
the formation of either of these, so
much is cut away, that the weight
of the polished gem does not exceed
the half of the rough crystal from
which it was wrought, wherefore
the value by weight of a cut
diamond is twice that of a rough
diamond, exclusive of the expence
of workmanship.

DI'AMOND SHAPED. Leaves are so
called when approaching to a
square, having four sides, of which
those opposite are equal : the four
angles are generally, two obtuse,
and two acute.

DIA'NCHOBA. A genus of attached
inequivalved bivalves; the attached
valve having an opening instead of
a beak, the other beaked and eared ;
the hinge toothless.

DrA'NDRiA. (from Sis, and dvrjp, Gr.)
The second class of plants in Lin-
naBus' artificial arrangement; they
have two stamens. This is a very
numerous class, consisting of three
orders, and comprehends all herma-
phrodite flowers having two sta-
mens.

DIA'JSTDRIAN. Having two stamens ;
belonging to the class Diandria.

DIA'PHANOUS. (Suxfiavf)?, pellucid,
from Suxfraivw, Gr. diaphane, Fr.)
Which may be seen through ;
transparent; pellucid. That which
allows a passage to the rays of
light.

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DIG

DI'APHRAGM:. (Sutyparffw,, Gr. dia-
pkragma, Lat. diaphragme, Fr.
diafragma, It.) A large transverse
muscle, which separates the chest
from the belly ; the midriff.

DIA'SPORE. (from BiaffTrelptv, Gr. to
disperse.) This name has been
assigned to the mineral from the
peculiarity that when exposed to
heat it decrepitates violently, and
is dispersed in numerous small
spangles. It is a rare mineral and
but little known : it is a combi-
nation of alumina and water, often
mixed with hydrate of iron . Speci -
fie gravity 3 -43.

DlATOMOUS SCHILLER SPAR, (from Sia,

through, and re/ii/a?, to cut, Gr.
from being easily cleavable in one
direction. The schillerstein of
"Werner ; diatomer schiller-spath
of Mohs ; diallage chatoyante of
Broehant.) An earthy mineral, a
combination of bisilicate of mag-
nesia, protoxide of lime and iron,
with hydrate of magnesia. It is
prismatic. Cleavage in two direc-
tions, forming together an angle of
about 135°; one cleavage perfect
and easily obtained, the other ap-
pearing only in traces. Hardness
= 3-5, — 4, Specific gravity =
2-6 — 2-8. Its colours are green,
grey, and brown. Occurs in granu-
lar concretions ; disseminated, and
seldom massive. Lustre shining
or splendent, and metallic pearly.
Opaque, and yields to the knife.
Streak greyish or yellowish white,
dull. Before the blow-pipe it
becomes hard, and assumes a me-
tallic appearance. Occurs in ser-
pentine and greenstone and in
secondary trap rocks. — Jameson.
Phillips.

DIBRA'NCHIATA. The first order in
the class Cephalopora. This order,
called by Pictet Cephalopoda Ace-
tabularia, has been divided by
him into two sub-orders, Octoheda,
and Docanida.

DI'CERAS. (from £«§ and Kcpa?, Gr.)

A genus of fossil shells discovered
in oolitic rocks. At Mount Saleve,
near Geneva, two species have been
discovered, but the genus has not
been met with in England, it is
thus named from possessing two
prominent spiral umbones, which
resemble two twisted horns.

DICHOBTJNE. (from $i'xa) bipartitio,
and powos, collis, Gr.) This genus
was proposed by Cuvier instead of
Anoplotherium minus. It is closely
allied to the Anoplotherioid genus
Xiphodon, the dental formula is
the same, only there is a slight
interval between the canine and
the first premolar in both jaws:
the first three premolars are sub-
compressed, sub-trenchant, but less
elongated from behind forwards
than in Xiphodon. — Owen. The
dichobune has points, arranged in
pairs, on the back molars of the
lower jaw. It has been found
fossil only, and in strata more
recent than the chalk.

DICHO'TOMOTTS. (from £/xa an<^ T6ytn/ftj,
Gr. dichotome, Fr. dicotomo, It.)
Forked ; regularly and continually
divided by pairs from the top to
the bottom : applied to stems divi-
ding into two parts ; example, the
misletoe.

DicfnoDox. The name of a genus
of extinct Artiodactyle Mammals
of the Eocene period. A portion
of the upper jaw of a species Dich-
odon Cuspidatus is in the British
Museum, as also a portion of a
lower jaw.

Dicn'ROigM. A term used in miner-
alogy to express a property
possessed by some bodies of ex-
hibiting different colours, when
examined by transmitted light, in
determinate directions. lolite,
tourmaline, and mica possess this
property.

DI'CHROIT. | (Of Greek etymology,

DI'CHROITE. j implying double co-
lour, because its crystals present a
very deep blue when viewed in a

DIG

[ 135]

DID

direction parallel to their axis,
while they appear of a brownish
colour, when viewed in a direction
perpendicular to this axis. Leon-
hard named this mineral Cordierite,
after Cordier, but Cordier himself
gave it the name of Dichroite.) A
mineral, called also iolite. The
prismatic quartz of Mohs; iolithe
of Haiiy. Dichroite is of a blue
colour, shining lustre, and con-
choidal fracture. It consists of
nearly 50 per cent, of silica, alu-
mina 30, magnesia 11, oxide of
iron 5, with a trace of oxide of
manganese. It occurs in granite
and gneiss.

DICO'CCOTJS. (from fil? and KOKKOS, Gr.)
A capsule which consists of two
cohering grains, or cells, with one
seed in each.

DICOTYLE'DON. (from §l<t and Korv\rj-
£wy.) A plant that has two coty-
ledons or seminal leaves.

DICOTYLE'DONOUS. Every plant the
embryo of whose seed is made up
of two lobes, or which possesses
two cotyledons, or seminal leaves,
is included in this great division
of the vegetable kingdom ; or is a
dicotyledonous plant. The stems
of dicotyledonous plants are all
exogenous, that is, they increase
externally by the addition of con-
centric layers from without ; these
concentric additions being made
annually, a vertical section of a
tree of this division will show, at
once, its age ; the number of rings
or circles marking its number of
years. Dicotyledonous plants may
always be distinguished from mono-
cotyledonous by their leaves : mono-
cotyledonous plants have the veins
of their leaves parallel and not
reticulated, while all dicotyledonous
plants have the veins of their leaves
reticulated.

DICTYO'GENJE. An order of plants,
belonging to the class Exogens,
comprising the yam and smilax.

DIDA'CTYLE. (&<5a/eTvXo9, Gr.) An

animal having two toes only.

DIDA'CTYLOTJS. Two-toed; having two
toes only.

DIDE'LPHIS. | (from &V and £e\0vs,

DIDE'LPHYS. j Greek, having two
wombs.) A genus of animals,
belonging to the class Mammalia,
order Terse. All the animals of
this genus are marsupial, that
is, possess an external abdominal
pouch, marsupium, or sac, in which
the foetus is placed after a very
short period of uterine gestation,
and where it remains suspended
to the nipple by its mouth, until
sufficiently matured to come forth
to the external air. The opossum
and kangaroo are examples. The
didelphys afford the only known
example of mammalian remains in
the secondary formations.

DIDE'LPHOID. Belonging to the genus
didelphys.

DIDY'MIUM. One of the sixty simple
or elementary bodies. Its symbol
is D.

DIDYNA'MIA. (from &? and Svvajus,
Gr.) The name given to the 14th
class in Linnaeus' s artificial arrange-
ment : it has four stamens, two
long and two short. This class is
easily distinguished from the 4th
class, Tetrandria, which has also
four stamens. The flowers of this
class are generally labiate ; corolla
monopetalous. It is divided into
two orders : Gymnospermia, with
four naked seeds in the bottom of
the calyx, and Angiospermia, the
seeds numerous and contained in a
seed-vessel. In the first order,
with the naked seeds, the plants
are mostly aromatic and wholesome,
including the mint, lavender, &c.
In the second, where the seeds are
contained in a seed-vessel, we find
digitalis, and other poisonous plants.

DIDYNA'MIC. ] Belonging to the class

DIDYNA'MOTTS. j Didynamia. Plants
having four stamens, two of which
are shorter than the others, are
called didynamous.

DIE

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D I K

DI'ELECTIC. (from Sta, through, and
ijfXe/cT/x?!/, Gr.) Any body through
which the electric fluid may be
transmitted.

DIGA'STRIC. (from $l<* and
Gr.) Having two bellies.

DI'GITAGRADA. In Cuvier's arrange-
ment, the second tribe of carnivora.
The name digitagrada has been
applied to them from the circum-
stance of the animals which com-
pose this tribe walking on the ends
of their toes. The lion, wolf, and
hyaena are examples.

DI'GITATE. j (digitatus, Lat.) A

DI'GITATED. j sort of compound
leaf, composed of two or more
leaflets. Botanists include under
the name digitate, binate and ternate
leaves, as well as those having more
than five leaflets, as the horse-
chesnut, which has seven leaflets.

DIGY'NIA. (from Sis and <ywrj, Gr.)
The second order in Linnaeus' s
artificial system, comprehending
such plants as have two styles, or
pistils.

DIGY'NIAN. } Having two styles, or

DIGY'NIOTJS. ) pistils ; belonging to
the order Digynia.

Sax. die, Germ. deic\ D. dyJc.

1 . A ditch ; a channel to receive
water.

2. A mound ; defence; wall; for-
tification.

3. Geologists use the word dike to
express a wall of mineral matter,
cutting through strata in nearly a
vertical direction. Trap dykes are
to be found in all parts of the
world, the composition of the rock
varying materially, even in the
dyke itself. Dykes are often of
great extent; one of the longest
with which we are acquainted has
been described by Prof. Sedgwick,
reaching from High Teesdale to
the confines of the eastern coast, a
distance exceeding sixty miles.
The trap dykes of Ireland have
been traced upwards of sixty

miles, and they are found cutting
through all the stratified rocks,
from the gneiss to the carboni-
ferous limestone inclusive. They
are known as greenstone, porphyry,
basaltic or other dykes, according
to the kinds of rock of which they
are composed. Lyell observes,
" That it is not easy to draw the
line between dikes and veins ; the
former are generally of larger
dimensions, and have their sides
parallel for considerable distances ;
while veins have generally many
ramifications, and these often thin
away into slender threads."

In the coal districts, the dykes
are an endless source of difficulty
and expence to the coal-owner,
throwing the seams out of their
levels, and filling the mines with
water and fire-damp. At the same
time they are not without their
use ; when veins are filled, as is
often the case, with stiff clay,
numerous springs are dammed up
and brought to the surface ; and by
means of downcast dikes valuable
beds of coal are preserved, which
would otherwise have cropped out
and been lost altogether. "What-
ever be the throw or difference of
level occasioned in the coal mea-
sures by these dikes, it never
happens, as might be expected,
that a precipitous face of rock is
left on the elevated side; or that
the lower side is covered by an
alluvial deposit, which connects
the inequality of the beds that are
in situ ; but the surface of the
ground covering the vein is rendered
level by the absolute removal of
the rocky strata on the elevated
side. The coal in contact with
the dykes is sometimes charred,
and resembles exactly the coke
obtained by baking coal in close
iron cylinders, in the process of
distilling coal-tar. In some parts
the coal is deteriorated to the
distance of twenty yards from the

D I L

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D I L

dike ; in others, to that of three or
four yards only. Sometimes the
coal first becomes sooty, and at
length assumes the appearance of
coke.

DiLifviAL. (diluvialis, Lat.) Relating
to the deluge. A term introduced
by Professor Buckland to distin-
guish accumulations consequent on
the deluge. " It is always," says
Dr. Mantell, " in diluvial beds
spread over the surface of plains,
or accumulated in the bottoms of
valleys, that the teeth and bones of
mammalia have been discovered in
various parts of England."

DILTT'VIAL DEPOSITS. "Next in order
to the alluvial deposits/' says the
Eev. Dean Conybeare, "we find a
mantle, as it were, of sand and
gravel indifferently covering all
the solid strata, and evidently
derived from some convulsion which
has lacerated and partially broken
up those strata, inasmuch as its
materials are demonstratively frag-
ments of the subjacent rocks,
rounded by attrition. The frag-
mented rocks constituting these
gravel deposits are heaped con-
fusedly together, but still in such
a manner that the fragments of any
particular rock will be found most
abundantly in the gravel of those
districts, where the parent rock
itself appears in titu among the
strata. In these deposits, and
almost in these alone, the remains
of numerous land animals are
found, many of them belonging to
extinct species, and many others
no longer indigenous to the coun-
tries where their remains are thus
discovered."

DILU'VIALIST. One who attributes
certain effects, denied by others, as
consequent on theNoachian deluge.

DILUVIAN. (Lat.) A name applied
by Professor Buckland to the super-
ficial beds of gravel, clay, and sand
which he considers to have been
produced by the Noachian deluge ;

loose and water-worn strata not at
all consolidated, and deposited by
an inundation of water.

The term Diluvium has been
applied to the general covering of
debris indiscriminately thrown to-
gether from all the strata by an
inundation which must have swept
over them universally, which in-
undation, known as the Noachian
deluge, was the last great geological
change to which the surface of our
planet appears to have been
exposed. By this name it is
proposed to distinguish it from the
partial debris produced by causes
now in operation, and to which the
term Alluvium is assigned.

Sir R. Murchison observes
"those coarse and sometimes far
transported fragments, to which
some geologists apply the term
diluvium, to avoid misconstruction,
I call drift. See Drift.

The Hon. Mr. Strangways ob-
serves "I need not say what is
intended by the term Diluvium;
it is meant to express that super-
ficial deposit which covers every-
thing, and is composed of almost
everything. Its composition and
thickness are very various : the
latter amounting to thirty, forty,
or even fifty feet. In some
instances it seems to form entire
hills. It is usually thickest in the
vallies, or on the flat summits
of some of the hills. Its compo-
sition, much as it differs in different
places, may be considered twofold ;
first, as the debris of rocks upon
which, or in the neighbourhood of
which, it is accumulated j secondly,
as that of a set of rocks totally
foreign to the country, the analo-
gies of some of which have been
recognised in situ at a vast distance,
while others remain yet to be
identified."

For the purpose of impressing

DIM

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D I

more strongly the distinction
between diluvial and postdiluvial
deposits, it will be convenient, says
Prof. Buckland, if geologists will
consent to restrict the term diluvium,
to the superficial gravel beds pro-
duced by the last universal deluge ;
and designate by the term al-
luvium those local accumulations
that have been formed since that
period.

"All that transported matter
commonly termed diluvium" says
Sir H. De la Beche, "requires severe
and detailed examination. At the
present time, there would appear
to be three principal opinions
connected with the subject. One,
supposing the transport to have
been effected at one and the same
period ; another, that several catas-
trophes have produced these super-
ficial gravels ; while a third would
seem to refer them to a long
continuance of the same intensity
of natural forces as that which we
now witness. These different
opinions, though they cannot each
be correct in the explanation of all
the observed facts, may each be so
in part ; and it were to be wished
that the phenomena were examined
without the control of a precon-
ceived theory. "

DIMEROCRIBI'TES. (from Sifieprjs, bi-
partite, and Kplvov, a lily, Gr.)
The name assigned by Professor
Phillips to a new genus, or sub-
genus, of encrinites belonging
to the Silurian rocks, he says
"the two following species, D.
decadactylus and D. icosidactylus,
appear to me really different, gene-
rically, from Actinocrinites, both
by the character of the intercostal
plates and the exact bifurcation of
the hands and arms. — Murchison's
Silurian System.

DIMO'RPHISM. In mineralogy, the
property which some substances
have of crystallizing in two differ-
ent forms belonging to two differ-

ent systems of crystallization.

DIMO'RPHOTJS. (from Sis, twice, and
W09), form, Gr.) Having two
forms.

DI'NGLE. A dale; a narrow valley
between hills ; a hollow.

DINOSATJ'RIA. The fourth order of
the class Beptilia; this order
which comprises Megalosaurus, Hy-
Iseosaurus, Iguanodon, Pelorosau-
rus, Regnosaurus, andPlateosaurus,
is altogether extinct.

DINOTHE'RIUM. (from £<Vos, and
Oijptov, Gr.) An extinct genus of
terrestrial mammalia. The dino-
therium may be considered to have
been the largest of terrestrial mam-
malia. The most abundant fossil
remains of this genus have been
found at Epplesheim, in Germany,
where, in 1836, an entire head of
this animal was discovered, mea-
suring about four feet in length by
three feet in breadth. In various
parts of the south of France, large
molar teeth and osseous fragments
of dinotheria have been found
occasionally, and these were refer-
red by Cuvier to a gigantic species
of tapir, and named by him Tapir
giganteus.

Subsequent discoveries have en-
abled Prof. Kaup to place the
dinotherium in a new genus, and
to establish the fact that it was an
herbivorous aquatic animal, in-
habiting marshes and lakes, and
that one species the D. giganteum,
sometimes attained the length of
eighteen feet. The dinotherium
holds an intermediate place between^
the tapir and the mastodon, sup-
plying a link between the cetacea
and pachydermata. The scapula,
or shoulder-blade, is the most re-
markable bone hitherto discovered,
belonging to this animal ; it resem-
bles that of the mole, and seems to
indicate that the fore-leg was
adapted for digging up the earth.
It appears also certain that this
huge creature was furnished with

D I 0

[ 139]

DIP

a proboscis, by means of which it
carried to its mouth the vegetable
food collected by its tusks and
claws. The dinotherium is refer-
rible to the miocene period.

A very remarkable peculiarity of
formation in the dinotherium con-
sisted in the possession of two
immense tusks, which were curved
downwards, and resembled those
of the upper jaw of the walrus,
but in the dinotherium these tusks,
nearly four feet in length, were
placed at the anterior extremity of
the lower jaw. These tusks are
supposed to have served as instru-
ments for raking and grubbing up
by the roots large aquatic vegeta-
bles. It is also thought that these
tusks might have been used by the
animal for the purpose of hooking
itself, as it were, to the bank, and
thereby enabling it to keep its
head above water during sleep ; as
well as for means of defence.
DJL'ODOI*. In Cuvier's arrangement,
a genus of fishes belonging to the
family Gymnodontes, and thus
named in consequence of their
jaws being undivided, and forming
one piece only above and one
below. Their skin is in all parts
so armed with spines, that they
resemble the case of the fruit of
the horse chesnut. Teeth supposed
to belong to diodon hisirix have
been found in the chalk.

"One day," says Mr. Darwin, "I
was amused by watching the habits
of a Diodon which we caught.
This fish is well known to possess
the singular power of distending
itself into a nearly spherical form.
Cuvier doubts whether the Diodon
in this state is able to swim, but
not only can it thus move forward
in a straight line, but likewise it
can turn round to either side.
This Diodon possessed several means
of defence. It could give a severe
bite, and could eject water from
its mouth to some distance. By

the inflation of its body, the
papillae, with which the skin is
covered, become erect and pointed.
But the most curious circumstance
was, that it emitted from the skin
of its belly, when handled, a most
beautiful carmine-red and fibrous
secretion, which stained ivory and
paper in so permanent a manner,
that the tint is retained with all its
brightness to the present day."
Mr. Darwin adds " I am quite
ignorant of the nature and use of
this secretion.'*

DKE'CIA. (from Sis and OIKO*, Gr.)
The twenty-second class of plants
in Linna3iis's artificial system. The
stamens and pistils are in separate
flowers, and situated on two sepa-
rate plants. The orders in this
class depend on the circumstances
of their male flowers.

DIO'PSIDE. (from diotyis, Gr. trans-
pectus, in reference to its trans-
parency.) A mineral known also
as alalite, baikalite, and musite.
It is a white or pale- green variety
of augite. It occurs massive, dis-
seminated, and crystallized. It is
found, generally, imbedded in Ser-
pentine. It consists of more than,
half silica, lime, about eighteen
per cent, magnesia, with a trace of
alumina and protoxide of iron.

The Abbe Haiiy states the prim-
itive crystal of Diopside to be an
acute rhomboidal prism. The mea-
surements of the angles by the
reflecting goniometer are 87° 5'
and 92° 55'. Diopside is con-
sidered by Haiiy to be a variety of
Pyroxene.

DIO'PTASE. (The Cuivre Dioptase of
Haiiy.) Emerald copper -ore, a very
rare mineral of an emerald-green
colour, consisting of oxide of cop-
per and silica in nearly equal pro-
portions, with about eleven per
cent, of water.

DI'ORITE. A variety of greenstone,
composed of hornblende and albite.

DIP. In geology, the downward

DIP

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DIP

inclination of strata. The point of
the compass towards which strata
incline is called their dip, and the
angle of such inclination with the
horizon is termed the dip, or angle,
of inclination. It sometimes hap-
pens that a stratum, without vary-
ing its direction, may be so bent
as to dip two ways in the same
mountain, like the sloping sides of
the roof of a house, or the letter V
reversed A.

DrpE'TALous. (from &V and TreVaXoi/,
Gr.) Having two flower-leaves or
petals.

DIP'LACANTHTJS. (from dta-Xco s, double,
and aicavOa, a spine, Gr.) A genus
of ich thy olites or fossil fishes, found
in the old red sandstone by Hugh
Miller and thus described by him,
"though the smallest ichthyolite
of the formation yet known, it is
by no means the least curious.
The length from head to tail in
some of my specimens does not
exceed three inches; the largest
fall a little short of five. The
scales, which are of such extreme
minuteness that their peculiarities
can be detected by only a powerful
glass, resemble those of the Cheira-
canthus. There are two dorsals,
the one rising immediately from
the shoulder, the other directly
opposite the anal fin. The ventrals
are placed near the middle of the
body. But the best marked char-
acteristic is furnished by the spines
of its fins, which are of singular
beauty. Each spine resembles a
bundle of rods, or rather the sculp-
tured semblance of a bundle of
rods, which finely diminish towards
a point, sharp and tapering as that
of a rush. The rest of the fin
presents the appearance of a mere
scaly membrane, and no part of
the internal skeleton appears. The
spines run deep into the body, as a
snip's masts run deep into her
hulk." Agassiz has enumerated
four species j D. crassispinus, D.

longispinus, D. striatulus, and D.
striatus.

DIPLO-NEFRA. See Helminthoida.

DIPLO'PTEEOTJS. The name given by
M. Agassiz, to a genus of ichthyo-
lites, belonging to the family of
Sauroid fishes, and found in the
old red sandstone. "Like the
genus dipterus, it has two dorsal
opposite two anal fins, but the
caudal fin is of a very peculiar
form ; the throat is very large, and
the jaws are armed with large
conical teeth." — Murchison. Silu-
rian System.

DI'PTERA. (from £ls and Tnepov, Gr.)
The sixth order of insects, or
insects having two wings. The
musca, or common fly ; the culex,
or gnat ; and the oestrus, or gad-
fly, are familiar examples. In
Cuvier's arrangement diptera forms
the twelfth class of insecta, and
their distinguishing characters are
said to be possessing six feet, and
two membranous extended wings,
accompanied generally by two
moveable bodies, called halteres,
which are placed behind the wings ;
the organs of manducation are a
sucker composed of squamous, sec-
taceous pieces, varying in number
from two to six, enclosed in an
inarticulated sheath, most frequent-
ly in the form of a proboscis. In
these divisions almost every ento-
mologist is disposed to make
alterations, and the systems pro-
posed are far too numerous to be
recounted.

DI'PTEROUS. Two-winged insects ;
belonging to the order Diptera.

DIPTERUS. (from £Js, twice, and
trrepov, a wing, Gr. Double wing.)
A genus of ichthyolites, belonging
to the old red sandstone, established
by Cuvier. This genus, says Sir
B. Murchison, was at first separated
by Valenciennes and Pentland into
four species, but after an attentive
examination of a great variety of
specimens, M. Agassiz has con-

DIP

[141 ]

D I S

eluded that although the genus
Dipterus ought to be retained, the
supposed four species are only
differently modified forms of the
same animal. The generic charac-
ter of the Dipterus, as now con-
firmed by M. Agassiz, consists in
" two dorsal fins opposite to two
similar anal fins, with a caudal fin
conforming to that of the genus
Palaeoniscus, in having the verte-
bral column prolonged into the
extremity of the tail." The dip-
terus is a characteristic fossil of
the tilestone. The dipterus differs
from the osteolepis chiefly in the
position of its fins, which are
opposite, not alternate ; the double
dorsals exactly fronting the anal
and ventral fins.

DIPT'BE. (from Svo two, and ?rvp, fire,
indicating the double effect of
fire to produce fire and phosphor-
escence in this mineral. It is
generally classed with scapolite.)
The schmelzstein of Werner,
A mineral, a variety of scapolite
found in the Pyrenees, thus named
by Haiiy. It consisists of silica
60*0, alumina 24-0, lime lO'O, and
some water and loss.

DIRECTION-. In geology, a term
applied to the course which strata
take at right angles to their line of
dip. — De la, JBeche.

Disc. | (diseus, Lat.)

DISK. ) 1. In conchology, the
middle part of the valves, or that
which lies between the umbo and
the margin ; the convex centre of
a valve, or most prominent part of
the valve, supposing it to lie with
its inside undermost.
2. In botany, the central florets of
a compound flower; the whole
surface of a leaf.

DI'SCINA. A genus of recent ovate,
unequal, roundish bivalves.

DISCO'POBA. A genus of cellepora,
found recent only, and differing
from tubulipora in the cells being
more sunk and less free ; and from

cellepora in having no lobated,
convoluted, or ramose expansions.

DISCO'BOLI. The name given to a
family of fishes, in Cuvier's ar-
rangement, from the disk formed
by their ventrals. The fishes of
this family form two genera.

Di' SCOLD. | 1. In the form of a disc.

DISCOI'DAL. ) In botany, plants, the
petals of whose flowers are set so
closely and evenly as to make the
surface plain and flat like a dish.
2. In conchology, when the whorls
are so horizontal as to form a
flattened spire.

DISCOI'DES. A genus of fossil echinus,
one species only of which has been
found, namely discoides subuculus.

DistfopHORA. The third order of the
class annulata.

DISCO'EBIS. A genus of microscopic
spiral discoidal univalves.

These have been thought by some
authors, and the number includes
Lamarck, to be found in a fossil
state only; but Parkinson states
that they are found recent on our
coasts.

DISCOBBI'TES. Fossil shells of the
genus discorbis.

DISCO'POBA. The name given by
Lamarck to a genus of fossil corals.
Three species are described as be-
longing to the Wenlock limestone,
namely, D. antiqua ; D. squamata ;
and D. favosa. The two last have
been thus named by Mr. Lonsdale.

DISI'NTEG BATED. Separated into in-
tegrant parts by mechanical di-
vision.

DISINTEGRATION. The separation of
a body into its integrant parts by
mechanical division ; the wearing
down of rocks ; utter separation of
particles.

DISK. See Disc.

DISLOCATION, (dislocation, Fr. dislo-
gazione, It.) The state of being
displaced; displacement of portions
of the earth's crust. According to
the theory of M. De Beaumont, the
principal dislocations of the earth's

D I S

[ 142]

D 0 D

crust of the same geological age
range in lines parallel to one and
the same great circle of the sphere ;
those of different ages are parallel
to different circles. The geological
era, consequently, of the elevation
of mountains, may be ascertained
from the direction of their axes of
movement.

DISPE'EMOUS. (from £ts, and mrcpfia,
Gr.) Two-seeded ; an epithet for
fruit containing two seeds only;
stellate and umbellate plants are
thus termed.

DISSE'PIMENT. (dissepimentum, Lat.)
In botany, the partition which
divides a capsule into cells. In
many plants the dissepiments do not
reach to the axis or centre, in some
plants the dissepiments are not
formed, or subsequently disappear,
and leave the placenta in the centre
of the ovarium, like a column, with
the seeds adhering to it.

DI'STHENE. | Disthene is the

DI'STHEN-SPATH. ) name given by
Haiiy, and Disthen-spath by Mohs,
to the mineral Kyanite or Cyanite,
which last, see.

DISTICHOPOBA. A genus of fora-
minated polypifers, established by
Lamarck. Mr. Parkinson thus
describes it: "A stony, solid, fixed,
ramose, and rather compressed
polypifer. The pores unequal and
marginal, placed on the two oppo-
site edges, in longitudinal rows,
and in the form of sutures ; stelli-
form, wart-like, projections are
scattered on the surface of the
branches."

DI'STICHOUS. (bla'Ti'xo's, Gr. distichum,
Lat.). Two -ranked ; applied to
leaves occupying two sides of a
branch, but not regularly opposite
at their insertion, as the fir, yew,
&c. ; applied also to branches when
they spread into two horizontal
directions ; and to flowers, placed
in two opposite ranks.

DI'TEUPA PLA'NA. A species of ptero-
podous mollusk, formerly called

Dentalium planum; found in the
lowest tertiary strata, especially
on the western coast of Sussex.

DIVERGING. In botany, applied to
the position of leaves during sleep,
signifying that the leaflets approach
at their base, and are open at their
summits.

DODE'CAGON. (from Su&eica and <yoWa,
Gr. dodecagone, Fr. dodecagono, It.)
A regular polygon having twelve
equal sides and angles.

DODECAHE'DEON. (from SivSeKa, twelve,
and e8pa, base, Gr.) A geometrical
solid, comprehended under twelve
equal sides, each whereof is a
pentagon. It is one of the regular
or plutonic bodies.

DODECAHE'DEAL. Having twelve equal
sides ; relating to a dodecahedron.

DODECAHE'DEAL COEUNDUM. Called
also Spinel ; the Spinelle and Pleo-
naste of Haiiy. There are two
varieties, the Ceylanite and Spinel
Ruby. Colours red, blue, brown,
black, green, and white. It con-
sists of alumina 74, silica 1 6, mag-
nesia 8, oxide of iron one and a
half, and lime 075 per cent.

DODECAHE'DEAL GAENET. A species of
garnet containing ten sub-species
or varieties ; these are the Grossul-
laire, or asparagus-green variety;
the Pyrenaite, or greyish-black
variety ; the Colophonite, or red
variety in granular concretions;
the Precious Garnet, or highly
crystallized and transparent red
variety ; the Topazolite, or yellow
variety; the Melanite, or velvet-
black opaque variety ; the Allo-
chroite, or brown, green, and grey
massive variety; the Pyrope, or
deep blood-red variety ; the Esso-
nite, or hyacinthine and orange-
yellow variety; the Common Garnet,
or brown and green variety, in gran-
ular concretions and translucent.

DODECAHE'DEAL MEECUEY. Called
also native amalgam, the Mercure
Argental of Haiiy. A mixture of
mercury and silver in the propor-

D 0 D

D 0 L

tions of nearly three-fourths of the
former, and rather more than one-
fourth of the latter. It is found in
quicksilver mines together with
cinnabar. It is of the colour of
silver, and regularly crystallized.

DODECA'NDBIA. (from SwSeica and
avrjp, Gr.) The eleventh class
of plants in Linnseus's artificial
system. The plants in this class
have from twelve to nineteen
stamens; the common houseleek
will illustrate it.

DODECA'NDRIAN". Belonging to the
class Dodecandria; having from
twelve to nineteen stamens.

DO'DO. A genus of birds belonging
to the order of galling. The bill
is contracted in the middle by two
transverse ruga3 ; each mandible is
inflected at the point ; and the face
is bare behind the eyes. The dodo
is a case in point serving strongly to
illustrate the views and opinions of
those who argue for the extinction
of species, even in the present day.
Lyell says, " The most striking
example of the loss, even within
the last two centuries, of a re-
markable species, is that of the
dodo, a bird first seen by the Dutch,
when they landed on the Isle of
France, at that time uninhabited,
immediately after the discovery of
the passage to the East Indies by
the Cape of Good Hope. It was of
a large size, and singular form ; its
wings short like those of an ostrich,
and wholly incapable of sustaining
its heavy body, even for a short
flight. In its general appearance
it differed from the ostrich, casso-
wary, or any known bird. Many
naturalists gave figures of the dodo
after the commencement of the
seventeenth century ; and there is a
painting of it in the British Museum,
which is said to have been taken
from a living individual. Beneath
the painting is a leg, in a fine state
of preservation, which ornithologists
are agreed cannot have belonged to

any other known bird. In the
museum at Oxford, also, there is a
foot and a head." "The dodo,"
as Dr. Man tell observes, "has been
annihilated, and become a denizen
of the fossil kingdom, almost before
our eyes. The bones of the dodo
have been found in a tufaceous
deposit, beneath a bed of lava, in
the Isle of France ; so that if the
very few remains of the recent bird,
above alluded to, had not been
preserved, these fossil relics would
have constituted the only record
that such a creature had ever ex-
isted on our planet. Nevertheless,
two centuries since, the dodo formed
the principal food of the inhabitants
of the Isle of France." No living
dodo has been seen since the year
1691.

DOLABE'LLA. A genus of univalvular
molluscs, the known species of
which are found in the Indian
ocean and in the Mediterranean.
They differ from Aplysias only in
the position of their branchia3 and
their surrounding envelope.

DOLA'BRIFOBJI. (from dolabra and
forma, Lat.) Hatchet-shaped; a
term more commonly applied to
leaves, cylindrical at the base and
having the upper part dilated,
thick on one edge and cutting on
the other.

DO'LEBJTE. A crystalline, granular,
distinct mixture of labradorite and
augite, with some titaniferous mag-
netic iron ore, and also with some
carbonate of iron and carbonate of
lime. General colour, dark grey ;
an augitic lava. — Juices.

DO'LITTM. (dotium, Lat. a tub, a tun.)
A subglobular ventricose univalve,
spirally ribbed in the direction of
the whorls; the inferior whorl
ample and ventricose; outer lip
crenated, or dentated, throughout
its whole length. Aperture oblong,
ample, and notched ; epidermis
light and horny.

DO'LOMITE. A variety, or modification,

D OL

[

of limestone, consisting of magne-
sian earth 48 parts, and calcareous
earth 52 parts. It derives its name
from Dolomieu, a French geologist.
There are three sub-species. Von
Buch maintains that limestone has
been converted into dolomite by its
proximity to porphyry in fusion,
and that the magnesia has been
transferred from magnesian miner-
als in the porphyry to the lime-
stone ; the magnesia being reduced
to vapour or gas. — Bdkewell.

The name Zetchstein (from zeche
and stein, Germ.) has also been
given to dolomite or magnesian
limestone. This is a calcareous
deposit, of a somewhat variable
aspect; it is fossiliferous. The
zechstein has not yet afforded any
remains of trilobites. It does not
appear to be a deposit widely spread
over the European area. As yet,
it is principally known in Germany
and England. Dolomite is gene-
rally of a light fawn or yellow
colour, and in some parts of a
crystalline, in others of a concre-
tionary character. It is included
in the new red sandstone group, its
position being immediately above
the coal measures. It is frequently
traversed by veins of carbonate of
lime, and there are sometimes met
with enclosed in it hollow geodes
of calcareous spar, with sulphate of
strontian and sulphate of barytes.

DO'LOMITE MA'BBLE. A variety of
dolomite of a white colour, occur-
ring in small granular concretions ;
these concretions are frequently so
loosely united as to fall apart by
the slightest pressure.

DO'MITE. A variety of trachyte, and
thus named from being found in
the Puy de Dome, in Auvergne, in
Trance. It has the appearance and
gritty feel of sandy chalk.

DO'NAX. (donax, Lat. £oVa£, Gr.)
Animal a tethys; an equivalved
inequilateral bivalve, with a crenu-
late margin, the frontal margin

4 ] DEE

obtuse; hinge with two cardinal
teeth in one valve, one in the
other; the lateral teeth one or two,
rather distant. The shells of this
genus are in general triangular,
inequilateral, flattened, truncated
before, and wedge-shaped. It is
found in sands and sandy mud, at
depths varying to ten fathoms.
Nineteen species have been de-
scribed, six of which have been
found in our seas. Several fossil
species occur in the neighbourhood
of Paris.

DO'EIS, In the Linnsean arrangement,
a genus of gasteropoda, belonging
to the class Mollusca. An animal
inhabiting a shell ; body, creeping,
oblong, and flat beneath; mouth
below, on the fore part; vent
behind, on the dorsum, surrounded
by a fringe ; feelers two and four,
retractile, and placed on the front
of the upper part of the body.
They are all marine, and are found
in every sea. In Cuvier's arrange-
ment doris is placed in the order
Nudibranchiata.

DO'RSAL. (dorsal, Fr. dorsdle, It. from
dorsum, Lat.) Appertaining to the
back, as the dorsal fin, the dorsal
ligaments, &c.

DO'ESUM. (dorsum, Lat.) The back :
the ridge of a hill is sometimes
called the dorsum. In conchology,
it generally means the upper surface
of the body of the shell, when laid
upon the aperture or opening. In
the genera of patella and haliotis,
the dorsum means the upper convex
surface.

DBE'ISSIMA. A genus of bivalve shells
separated from mytilus by Dr.
Vanbeneden; it is regular, equivalve,
inequilateral ; umbo with a septum
in its interior; there are three
muscular impressions. The great
depth of the anterior side, together
with the nearly semilunar figure,
distinguish it from mytilus. It
has been found fossil in the second-
ary and tertiary rocks.— Lycett.

DEI

DUD

DRIFT. " All those coarse and some-
times far transported materials, to
which some geologists apply the
word diluvium, I," says Sir R.
Murchison, " to avoid misconstruc-
tion, designate drift. Diluvium,
as used by M. Elie de Beaumont
and the modern foreign geologists,
means precisely what I term drift.
Geologists having now completely
ascertained that each region of the
earth has its own superficial diluvia,
produced by distinct and separate
action, the unambiguous word drift
is proposed, which when preceded
by the name of the tract whence
the materials were derived, ex-
presses at once the intended mean-
ing. Hence Silurian drift, Northern
drift, Scandinavian drift, &c., &c."
Sir R. Murchison. Silurian System.

DRUPE, (drupce, Lat. £/w7re7n)s, Gr.)
A pulpy pericarp, or seed-vessel,
containing a single hard and bony
nut, to which it is attached : the
epicarp and sarcocarp separable from
each other, and from the endocarp,
which is stony; the nectarine,
peach, apricot, &c., furnish us with
familiar examples.

DRUPA'CEOUS.

1 . Having the characters of a drupe,
as drupaceous fruit.

2. Bearing drupes, as drupaceous
trees.

DRUSE. A hollow space in veins of
ore, generally lined with crystals.

DRUSY. This word says Phillips,
" has been adopted from the Ger-
man term drusen, for which we
have no English word. The sur-
face of a mineral is said to be
drusy when composed of small
prominent crystals, nearly equal in
size; it is often seen in iron
pyrites."

DUCT, (ductusy Lat.) A tube, canal,
or passage through which anything
is conveyed.

1. In anatomy the ducts are very
numerous ; thus we have the cystic

duct, the hepatic duct, the nasal
duct, &c., &c.

2. In botany, ducts are membra-
nous tubes, having their sides dotted
or barred; they are large enough
to be visible to the naked eye, and
are plainly seen when a cane, or
vine-branch, is cut across.

DU'CTILE. (ductilis, Lat. ductile, Fr.
duttile, It.) That may be drawn
out into greater length without
breaking. The term is applied to
metals only, and is sometimes con-
founded with malleable, whereas
the two have very different signifi-
cations ; thus copper is both malle-
able and ductile, but lead is only
malleable and not ductile; some
metals are neither malleable nor
ductile, but brittle, as antimony,
manganese, tellurium, &c., &c.

DUCTI'LITT. (ductilite, Fr. duttilitci,
It.) That property which metals
possess of being drawn out into
greater length with diminished
thickness, without separation of
parts. The French use the word
ductilite to express malleability;
but we do not. "La ductilite est
un synonyme de malleabilite." —
Diet. De 1} Acad. Frangoise.

DUDLEY ROCKS. Called also Wenlock
Rocks. A marine formation, com-
posing one of the divisions of
the Silurian system. The Dud-
ley rocks have been sub -divided
into Dudley limestone, a mass
of highly concretionary grey
and blue subcrystalline limestone ;
and Dudley shale, an argillaceous
shale, of a liver or dark grey
colour, rarely micaceous, with no-
dules of earthy limestones. Amongst
the organic remains contained in
the Dudley rocks may be enume-
rated corals and crinoidea, in great
abundance ; trilobites, &c., &c.

DUDLEY FOSSIL. } Names given to

DUDLEY TRILOBITE. ) that species of
Calymene named by M. Ad. Brong-
niart C. Blumenbachii. This spe-
cies has obtained the name of

DUG

[ 146]

E A K

Dudley fossil in consequence of its
being found in such great abun-
dance in the neighbourhood of
Dudley; it is however by no
means confined to that locality,
but is met with over a considerable
area through England, Germany,
Sweden, and North America.
DTTG. The teat or nipple.
DtfGONG. A species of phytophagous,

or herbivorous, cetacea.
DUJSTE. By geological writers, this
word is used to signify a low hill,
or bank, of drifted sand, and in no
respect is synonymous with down,
as might be inferred from Todd and
"Webster. The downs, both north
and south, are very extensive ranges
of chalk hills, principally covered
with short grass, affording excellent
herbage for sheep, whereas dunes
are banks of drifted sand, scarcely
of sufficient heights to be ranked as
hills.

DUODE'NTJM. (duodenum, Lat. duode-
num, Fr.) The first of the small
intestines, immediately adjoining
the stomach, and called duodenum
from its length, supposed to be
twelve inches.

DUST. In botany, the pollen of the
anther. The pollen or dust is con-
tained in the anther. In dry and
warm weather the anther contracts
and bursts, when the pollen is
thrown out. It is found, from
microscopic examination, that each

particle of dust is generally a mem-
branous bag, either round or an-
gular, smooth or rough, which on
meeting with any moisture instantly
bursts and discharges a subtile va-
pour. To the perfecting the seeds
of plants, it is necessary that the
pistil, or female organ, be impreg-
nated by the pollen of the anther ;
the fluid contained in the pollen,
when the anther bursts, penetrates
the stigma, and is conveyed to the
seeds, whereby they are rendered
fertile, or endued with the property
of growing, and producing a plant
resembling the parent one.

DYKE. See Dike.

DYNAMICS. (from Swapis, force,
power, Gr.) That branch of
mechanical science which treats
of moving powers, and of the
action of forces on solid bodies,
when the result of that action is
motion.

DYNAMICS GEOLOGICAL. These include
the nature and mode of operation
of all kinds of physical agents, that
have at any time and in any manner,
affected the surface and interior of
the earth. — £uckland's Bridgewater
Treatise.

DYSO'DILE. (from dvawfy?, graviter
olens, fotidus, Gr.) A mineral of a
greenish colour found near Syracuse,
which burns like coal, but gives
out during its combustion a most
intolerable odour.

E

EA'GLE- STONE, Called also setites. A
variety of argillaceous iron ore, of
a nodular form, something resem-
bling a kidney in shape, and con-
taining a sort of loose kernel. It
obtained its name from a supposition
that it was either found in, or had
dropped from, the nests of eagles.

EABTH'S CBTJST. That portion of our
planet which is accessible to our
observation and inspection.

" It comprises," says Sir C«
Lyell, " not merely all of which the
structure is laid open in mountain
precipices, or in the cliffs over-
hanging a river, or the sea, or

EAR

[147]

E C H

whatever the miner may reveal in
artificial excavation ; but the whole
of that outer covering of the planet
on which we are enabled to reason
by observations made at or near
the surface."

It has been concluded, both from
astronomical and geodesical obser-
vations, that the figure of the
earth is a spheroid. This spheroid
has been considered as one of
rotation, or such figure as a fluid
body would assume if possessed of
rotatory motion in space. The
amount of the flattening of the
poles, or the difference of the
diameter of the earth from pole to
pole, and its diameter at the
equator, has been variously esti-
mated, the commonly received
opinion is, that the polar axis is to
the equatorial diameter as 304 to
305, the difference in favour of the
equatorial diameter amounting to
26 miles. As regards the density
of the earth, various opinions have
been formed; it however appears
certain, that the internal exceeds
that of the solid superficial density.
Daubuisson infers from the obser-
vations of Maskelyne, Cavendish,
and Playfair, that the mean density
of the earth is above five times
greater than that of water, and
consequently, about twice that of
the earth's mineral crust. Laplace
calculated the mean density to be
1'55, the solid surface being 1.
Eaily, in his astronomical tables,
states the mean density of the earth
to be 3*9326 times greater than
that of the sun, and to that of
water as 11 to 2.

A very great proportion of the
earth's surface bears the most in-
contestible evidence of having been
deposited under water ; of having
been, at one time, not only sub-
merged by the sea, but gradually
accumulated at its bottom. Nearly
ail the strata contain the remains
of shells in great profusion, the

bones and scales of fishes, fragments
or entire trunks of timber, frag-
ments also of stone, very commonly
in the form of pebbles, evidently
worn and rounded by friction
under water.

The term " earth's crust" relates
only to the comparative extent of
our knowledge beneath its surface,
and is not used with the intention
of conveying an opinion that the
earth consists only of a crust, or
that its centre is hollow; for of
this we know nothing. The
nature of the earth's crust is most
readily studied in mountains,
because their masses are obvious;
and also because, as they are the
chief depositories of metalliferous
ores, the operations of the miner
tend greatly to facilitate their
study.

EBOU'LEMENT. (Fr.) Fall of any
detached rock. The fall of parts
of mountains is so common an oc-
currence in the Alps, that it is
expressively called an eboulement,
from the verb ebouler ; tomber en
ruine.

EBU'BNA. (from eburnus, Lat. ivory.)
An oval or elongated univalve with
a deeply umbilicated columella;
the aperture oblong, and notched
at the bottom. The recent eburna
lives in sandy mud. Fossil eburnae
are rarely met with. Parkinson
states that Lamarck does not notice
them among the Paris fossils, but
that a shell exists among the Essex
fossils which he names Eburna
glabrata. Dr. Mantell gives eburna
as a fossil of the chalk marl, but
affixes a note of interrogation to it,
as though doubtful.

ECHI'NIDEA. An order of the class
Echinodermata, and divided into
three families, viz., Spatangoidea,
Clypeasteroidea, and Cidarida3.

ECHIDNIS. A fossil resembling an
orthoceratite, its specific character
being the alternate circular risings
and depressions on its surface. .

E C H

L 148]

E C H

ECHI'NATE. | (echinatus, Latin.)

E'CHINATED. j Bristled like a
hedge-hog; set with spines; having
sharp points or spines.

ECHI'NIDAN. A fossil belonging to
the class Echinoderms. Professor
Auckland states that the family of
echinidans appears to have extended
through all formations, from the
epoch of the transition series to the
present time.

ECHI'NITE. The fossil echinus, or
sea-urchin. Echinites vary greatly
both in form and structure, and are
arranged accordingly into many
sub-genera; they are all marine.
The chalk formation abounds with
these fossil shells, some of which
are exceedingly beautiful from their
elegant and minute decorations.
The Ananchytes cretosus, a sub-
genus, is found in some places in
shoals, and in every condition from
the youngest to the oldest age. The
Spatangus cor-marinum, another
sub-genus, silicified, is frequently
found on our shores and in our
gravel-pits, and the spines of the
different sub-genera, detached from
the shells, are very numerously
dispersed throughout the chalk.
The various opinions entertained
of the real nature of echinites are
curious and amusing. Rumphius
believed that they, as well as belem-
nites, fell from the sky. Monnius
supposed that they were the petri-
fied eggs of serpents. The Romans
imagined they were the eggs of
toads, or petrified toads themselves,
or that they fell from the clouds
during heavy rains and thunder.
Some authors supposed that they
were figured stones, to which
nature had assigned their peculiar
form, and these and various other
absurd notions were entertained
until the time of Aldrovandus, who
asserted the true origin of these
fossil bodies.

ECHI'NTJS. (echinus, Lat. e^u/os,
Gr.) The sea- urchin, or egg. The

echinus is included in the order
Echinodermata, being covered by
a hard and coriaceous skin. The
shell is spherical, and composed of
an immense number of polygonal
plates, closely fitted to each other,
and has attached to it many spines
or prickles, which serve as instru-
ments of motion. The mouth of
the echinus is placed beneath, and
is provided with several triangular
teeth. Some species of the echinus
are edible, more especially the E.
Esculentus. The echinus feeds
principally on small shell-fish,
which it seizes with its tentacula.

ECHI'NODERMS. Simple aquatic ani-
mals, with a radiated, globular, or
elongated body, covered with a
spiny shell or coriaceous skin.
They are entirely marine, slow-
moving or fixed, predaceous, and
commonly provided with a dis-
tinct nervous, muscular, sangui-
ferous and respiratory system, and
organs of sense. They are termed
echinoderms, from the surface of
their skin being covered generally
with calcareous spines, whether
the surface be calcified or calca-
reous.— Prof. Grant.

ECHINODEBMATA. The seventh class
of the sub kingdom Annulosa.
This class comprises seven orders,
namely Holothuridse, Echinidea,
Ophiuridae, Asteridea, Crinoidea,
JBlastoidea and Cystidea; the two
last, in italics, are entirely extinct.

ECHINA'NTHUS. The name given to a
section of Catocysti by Leske. The
genus echinanthus comprises all the
echinites of this section. Of this
genus there are many species. The
echinanthus was named Scutum
by Klein. The shells are of an
irregular figure, resembling a buck-
ler. On the base, which is concave,
five grooves pass from the margin,
and terminate at the mouth in the
centre. Five rays ornament the
upper part. The mouth is placed
in the centre of the base, and is of

E C H

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E G Y

a pentagonal form. The whole of
the surface is marked with very
small depressions, of a circular
form, with central tubercles. —
Parkinson.

ECHINABA'CHNIUS. (from e%u>os and
a pa^yr}, Gr.) A genus of echini
belonging to the class Pleurocysti.
To this genus Klein gave the name
Arachnoides.

ECHINOCO'BYS. A genus of fossil
echini tes, thus named by Leske,
belonging to the class Catocysti.
This genus comprises all those
echinites which Klein divided into
Galeae and Galeolse. There are
several species.

ECHINODI'SCUS. The name given by
Breynius to a section of echini
belonging to the class Catocysti.
The echinodiscus is of a depressed
discoidal figure, whence it has its
name, nearly flat on both sides.
Echinodisci are found both recent
and fossil. There are many species.

ECHTNOPHO'BA. A genus of stony
polypifers, recent, and found in the
sea of New Holland. The Echino-
pJiora is fixed, flat, expanded in a
rounded membrane, free, and bear-
ing the form of a leaf, finely stri-
ated on both sides.

ECPYBO'SIS. The sect of Stoics taught
that catastrophes were of two kinds;
the cataclysm, or destruction by
deluge, which sweeps away the
whole human race, and annihilates
all the animal and vegetable pro-
ductions of nature; and theecpyrosis,
or conflagration, which dissolves the
globe itself. — LyelL

E'CLOGITE. A greenstone rock, com-
posed of green smaragdite and red
garnet.

EDENTA'TA. The twelfth order of
the class mammalia, divisible into
four families ; Tardigradse, Gravi-
grada3, Dasypida3, and Myrmeco-
phagida?.

EDENTA'TED. (edentatus, Lat. edente,
edentato, It.) Without teeth.

EDI'JNGTOIUTE. A mineral, resembling

some varieties of felspar and preh-
nite.

EDMO'NDIA. A genus of fossil bivalve
shells, established by M. Koninck ;
he describes it as convex, equivalve,
inequilateral, transverse, sub-oval,
or rotund, the lunuli gaping, with
no cardinal teeth, with an internal
transvere hinge, the ligament in-
ternal, and very small. One species,
the E. unioniformis, is recorded
from the carboniferous limestone of
Holland. — Lycett.

EDBYOPHTHA'LMIA. The second order
of Crustacea, comprising Laemodi-
poda, Amphiboda, and Isopoda.

EFFLOBE'SCENCE. (effloresce, Lat. efflo-
rescence, Fr. efflorescent, It.)

1 . Production of flowers.

2. Excrescences in the form of
flowers.

3. The pulverescence of crystals on
exposure to the atmosphere.

It is applied, says Phillips, to
such minerals as are found in ex-
tremely minute fibres on old walls,
&c.
EFFLOBE'SCENT.

1. Shooting out in the form of
flowers.

2. Becoming pulverulent on expo-
sure to the atmosphere ; the reverse
of deliquescent.

EFFO'SSION. (from effodio, Lat.) The
digging out of the earth, as of
fossils, &c.

EFFU'SE. In conchology, a term
applied to shells where the aper-
ture is not whole behind, but the
lips are separated by a gap.

E'GEBAN. A variety of idocrase or
vesuvian, occuring near Eger, in
Bohemia, whence its name.

EGE'BIA. A genus of fossil bivalves
belonging to the tertiary formation.

EGYPTIAN JASPER. Called also Egypt-
ian pebble. The Egyptischer jaspe
of Werner. Jaspe Egyptien of
Brongniart and Brochant. Quartz
agathe onyx of Haiiy. A sub-
species of jasper, characterized by
its globular or spheroidal form,

E L A

[150]

E L E

sometimes flattened, and by the
arrangement of its colours. These
colours are brown, of different
shades, yellow and grey, always
arranged in zones, or bands, more
or less concentric, sometimes inter-
mixed with spots and dentritic
marks. According to Dr. Clarke,
Egyptian jasper is found in great
abundance scattered over the sur-
face of the sandy desert eastward
of Grand Cairo, in the sand near
Suez in Egypt, and in the adjoin-
ing deserts ; it forms a constituent
part of extensive beds of a siliceous
breccia, which, by their decompo-
sition furnish these pebbles in a
loose state. — Cleaveland. — Phillips.

ELA'OLITE. (from e'Xata, an olive,
and X/009, a stone.) A sub-species
of pyramidal felspar, known also as
fettstein, or fatstone, a name given
to it from its greasy feel.

ELASMOTH'EEITJM. The name given
by Fischer to what he considered
an extinct genus of fossil pachy-
dermata.

"What," says Griffith, "dis-
tinguishes the elasmotherium from
all known animals is that the
Iamina3 of the teeth form a very
elevated shaft, which grows like
that of the horse, preserving a long
time its prismatic form, and that
they descend vertically through the
entire extent of this shaft, not
dividing into roots until after a
considerable time, while, in other
animals, they unite promptly into a
single osseous body which is itself
speedily divided into roots ; and
also that their section has its edges
festooned like those of the trans-
versal bands of the molars of the
Indian elephant."

The only relic hitherto found
occurred in Siberia.

ELA'STIC. (from e'Xao?, Gr. &lmtiquey
Fr.) Having the power of re-
turning to the form from which
it is distorted or withheld; springy.
It is applied to such minerals as

being bent have the property of
springing back to their original
form, and therein differ from those
that are merely flexible ; thus, talc
is only flexible, mica is elastic.

ELA'STIC MINEBAL PITCH. Called also
elaterite and mineral caoutchouc ;
a brown, massive, elastic variety of
bitumen : it consists of about 52
per cent, of carbon, 40 per cent of
oxygen, 0*15 of nitrogen, and 8
per cent, of hydrogen.

ELA'TERITE. Another name for elas-
tic mineral pitch.

ELE'CTEUM. Argentiferous gold ore,
a variety of hexahedral gold, of a
pale brass-yellow colour. Pliny
informs us that it was a mixture
of gold and silver, and thus writes,
" Omni auro inest argentuin vario
pondere. TJbicunque quinta argenti
portio est, electrum vocatur." It
has been attempted to prove that
platinum is the electrum of the
ancients, but such is not the case.

ELEME'NTAEY. (elementarius, Lat ele-
mentaire, Fr. elementdle, It.) Un-
compounded; uncombined; simple;
primary.

ELEME'NTAET SUBSTANCES. There are
about sixty simple, or elementary
substances at present known, that
is, substances, which, under the
conditions yet applied to them,
are found to be incapable of further
analysis, and are therefore called
simple, or elementary substances.

ELEVA'TION. The question of the
elevation and subsidence of the
earth's surface is one which long
gave rise to controversy, and various
were the arguments adduced in
support of, and in opposition to,
opinions which now are unhesita-
tingly and universally received, and
on which the vitality, as it were,
of geology depends. It may not,
however, be amiss to quote here
some of the views of our best and
soundest geologists, on a point of so
great importance, and one which,
to the Neophyte, seems often so

E L E

C

startling. The fact of great and
frequent alteration in the relative
level of the sea and land is so well
established, that the only remaining
questions regard the mode in which
these alterations have heen effected.
The evidence in proof of great and
frequent movements of the land
itself, both by protusion and subsi-
dence, and of the connection of
these movements with the opera-
tions of volcanoes, is so various and
so strong, derived from so many
different quarters on the surface of
the globe, and every day so much
extended by recent inquiry, as
almost to demonstrate that these
have been the causes by which
those great revolutions were effect-
ed ; and that although the action
of the inward forces which protrude
the land has varied greatly in dif-
ferent countries, and at different
periods, they are now, and ever
have been, incessantly at work in
operating present change, and pre-
paring the way for future alteration
in the exterior of our globe. — 'Dr.
Fitton.

Sir C. Lyell says, "We may
regard the doctrine of the sudden
elevation of whole continents by
paroxysmal eruptions as invalidated.
In 1822, the coast of Chili was
visited by a most destructive earth-
quake; when the district round
Valparaiso was examined on the
following day, the whole line of
coast, for the distance of above 100
miles was found raised -above its
former level. The area over which
this permanent alteration of level
extended was estimated at 100,000
square miles; the rise upon the
coast was from two to four feet,
inland it was from five to seven
feet." The following extracts are
from Mr. Bake well's Introduction
to Geology : " The granite-beds in
the Alps were not elevated till a
late geological epoch, after the de-
position of the oolites and chalk.

] E L E

M. Elie de Beaumont has proved,
that whole mountain-chains have
been elevated at one geological
period, that great physical regions
have partaken of the same move-
ment at the same time, and that
these paroxysms of elevatory force
have come into action at many
successive periods. I agree with
Professor Sedgwick, and M. Elie
de Beaumont, that the elevation of
mountain-ranges, where the beds
are nearly vertical, was effected by
a sudden and violent upheaving,
yet I am persuaded that the eleva-
tion of continents, or extensive
tracts of country, was (as Sir C.
Lyell observes) a long continued
process, and that these operations
were distinct from each other. The
elevation of large continents and
islands, was not effected by the
same operation, which upraised the
primary rocks. I consider it pro-
bable, that all large tracts of coun-
try or continents emerged slowly
from the ocean, forming at first
mountainous islands, before the
lower countries were raised above
the level of the sea. In the Weal-
den beds the strata have been up-
heaved and submerged more than
once. All the coal-basins were
either formed in inland marshes or
lakes, or were surrounded by dry
land ; but a great submergence of
the land took place, and they were
covered in many parts by thick
depositions of marine limestone.
At a subsequent period they again
emerged from the ocean with a
covering of marine secondary strata.
The elevations of limited portions
of the earth's surface, at a distance
from any known volcanic agency,
are not uncommon. Loose stones,
or shingles of an ancient sea-beach,
are found at heights considerably
above the present level of the sea
in many parts of England. The
elevation of extensive islands or
continents was probably always

ELY

[ 152]

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accompanied by the depression of
other portions of the earth's crust."
M. Elie de Beaumont has discovered
probable evidence of no less than
twelve periods of elevation, affect-
ing the strata of Europe. The Isle
of Portland affords us an admirable
example of alternate elevations and
submersions of strata.

1. "We have evidence of the rise
of Portland stone, till it reached
the surface of the sea, wherein it
was formed.

2. This surface became, for a
time, dry land, covered by a tem-
porary forest, during an interval
which is indicated by the thickness
of a bed of black mould, called the
dirt-bed, and by the rings of
annual growth in large petrified
trunks of prostrate trees, whose
roots had grown in this mould.

3. "We find this forest to have
been gradually submerged, first
beneath the waters of a fresh water
lake, next of an estuary, and
afterwards beneath those of a deep
sea, in which cretaceous and ter-
tiary strata were deposited.

4. The whole of these have been
elevated by subterranean violence.
—•Prof. BucUand.

It is now clearly ascertained that
the whole country from Prederick-
shall, in Sweden, to Abo, in
Finland, is slowly and visibly
rising, while the coast of Greenland
is being gradually depressed.
Certain parts of Sweden are being
gradually elevated at the rate of
two or three feet in a century.

ELY'TBA. (from eXvrpov, Gr.) The
hard cases which cover the wings
of coleopterous insects; the wing-
sheaths, or upper crustaceous
membranes, which cover the true
membranous wings of insects of the
beetle tribe.

EL'VAN. The name given to a stone
which frequently occurs in the
mines of Cornwall : it is various in
its appearance and composition as

well as in its relative situation,
and in its apparent effects on
metallic veins and lodes. It occurs
in Cornwall in inclined strata,
which are scarcely sufficiently
horizontal to be called beds : the
miners call these channels or
courses, Elvan courses.

ELV'AN COTJESE. The Elvans all along
the coast of Cornwall occur in beds
and veins of every possible thick-
ness, from forty feet to half an
inch, sometimes overlying, but more
frequently traversing the killas in
various directions, under such
circumstances as are apparently
irreconcilable with any other
theory, than that which supposes
them to be of contemporaneous
formation with the rock containing
them ; the result of some play of
affinities which allowed a part of
the mass to assume a crystalline
texture, while its coarser and more
abundant portions were left to
arrange themselves in the slaty or
tortuous form which characterizes
the killas.

ELVE'KTTE. Quartziferous porphyry.

EHA'EGINATE.

EMA'BGINATED.

1. In botany, applied to leaves
terminating in a small acute notch
at the summit.

2. In conchology, to shells having
no margin; or when the edges,
instead of being level, are hollowed
out.

3. In mineralogy, to minerals
having all the edges of the primi-
tive form truncated, each by one
face.

4. In entomology, when the end
has an obtuse incision.

EMAEGIN'ULA. A genus of obliquely
conical univalves, the vertex in-
clined, and the posterior margin
notched. Pound both recent and
fossil.

E'MBEYO. (fyfipvov, Gr. embryon,
Lat. embryon, Pr.)

J" j (emargino, Lat.)

E M B

[ 153 ]

E M y

1. In botany, the germ, or most
essential part of a seed, and with-
out which no seed is perfect, or
capable of re-production. The
embryo is usually placed within
the substance of the seed, either
central, excentral out of the centre,
or external ; its direction is curved
or straight, and in some instances
spiral. — Flora Medica.

2. The offspring yet enclosed in
the uterus, and in the early stage
only of uterogestation ; it is after-
wards called the foetus.

EMBOUCHU'KE. (Er.) The mouth of
a river, or that part where it
enters the sea.

E'MERALD. (emeraude, Er. smerdldo,
It. fjiapa^o's, Gr. smaragdus, Lat.)
A precious stone of a green colour,
found crystallized. Under the
genus emerald are comprised two
species, the first, the prismatic
emerald, or euclase of Werner and
Haiiy, and prismatischer smaragd
of Mohs ; the second, the rhombo-
hedral emerald, or rhomboedrischer
smaragd of Mohs. This last species
contains two varieties, the precious
emerald and the beryl, or common
emerald. Prof. Jameson places
the emerald amongst the members
of the schorl family, dividing it
into sub-species, namely, emerald
and beryl. He observes, " its
characteristic, and, we may almost
say, its only colour, is emerald
green, of all degrees of intensity
from deep to pale. The deep
sometimes inclines a little to verdi-
gris green, and oftener to grass-
green : the pale varieties sometimes
nearly pass into greenish- white."
Prof. Phillips says "the only im-
portant difference between emerald
and beryl is in their colours ;
which, since they present an
uninterrupted series, is altogether
insufficient for a division of the
species. The emerald and beryl
are crystallized compounds of an
earth called glucina, with silex,

alumine, lime, and oxide of iron
the splendid green of the emerald
is attributed to the presence of
oxide of chromium. The finest
emeralds are brought from Peru.
Vauquelin, in analysing the eme-
rald, first discovered the earth
which he called glycina, or glucina.
Cleaveland says " the emerald is
always crystallized ;" Jameson
states, " it is said to occur masive,
and in rolled pieces," but of such
Werner has seen no specimens ;
Phillips says " it occurs in rolled
masses in secondary depositories."
The primitive form, of which Haiiy
has described six modifications, is
a regular hexahedral prism, whose
sides are squares. The integrant
particles are triangular prisms.
The emerald yields readily to
cleavage, parallel to all the planes
of its primary form. Before the
blow-pipe it fuses into a white, and
somewhat vesicular, glass. Speci-
fic gravity from 2'60 to 2'77.
Hardness from 7'5 to 8\ It
scratches glass easily, quartz with
difficulty.

E'MEKY. (emeri, Fr. pierre ferrugi-
nemefort dure, dont on se sert pour
polir les m&taux et les pier res.)
The schmiergel of Werner; eme-
r'il of Brongniart ; corindon granu-
laire of Haiiy. A massive, nearly
opaque, greyish-black variety of
rhombohedral corundum, consist-
ing of alumina 86, silica 3, oxide
of iron 4. Emery sometimes occurs
in fine granular distinct concretions.
Lustre glistening ; fracture uneven,
and sometimes splintery. It is
sufficiently hard to scratch quartz.
Specific gravity from 3 '6 to 4. It
is found in Europe, Asia and
America. Emery powder is used
for the purpose of polishing metals
and hard stones, and also for
domestic purposes, sprinkled upon,
and fastened to, brown paper;
then called emery-paper.

E'MYS. (from rj /LIVID, Gr.) Emydes,

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pi. The fresh-water turtle or
tortoise. This has five nails to the
fore feet, and four to the hind ones.
Most of them feed on insects,
email fishes, &c. Their envelope
is generally more flattened than
that of the land tortoises. In fresh-
water tortoises all the toes are
nearly equal, and of moderate
length ; in land tortoises the toes
are also nearly equal, but they are
short; in the marine tortoise, or
turtle, the toes are all long, and
the middle toe of the fore paddle is
considerably longer than the rest.
Fossil species of the emys have
been discovered in the "Wealden, as
well as in lacustrine deposits of the
tertiary period.

ENA'LIOSAUB. An extinct genus of
saurians of the old red sandstone.

ENCE'PHALON. (e<y/ce'0aAos, Gr.) The
brain.

E'NCRINAL. Pertaining to encrinites ;
composed of encrinites ; containing
encrinites.

E'NCRINITE. (from Kplvov, Gr. lilium,
Lat; a lily.) A fossil encrinus. A
genus of the order Crino'idea,
known by the name of stone-lily.
Mr. Miller gives the following
description of the genus Encrinites,
or true lily-shaped animal. "A
crinoidal animal with a column
formed of numerous round depres-
sed joints, adhering by a radiating
grooved surface, and becoming sub-
pentangular near the pelvis, which
is composed of five pieces, giving a
lateral insertion to the first series
of costal plates, to which the
second series and scapulae succeed,
whence the tentaculated arms or
fingers proceed, formed by double
series of joints. Dr. Mantell ob-
serves, "there are some kinds
of star-fish which, instead of the
five flat rays of the common species,
have jointed rays, which surround
the body and mouth, like the
tentacula of the polypus. These
arms are composed of thousands

of little bones, or ossicula, and
the whole are inclosed in the
common integument or skin. The
asterias is a free animal, floating
at liberty in the water. Now,
if we imagine a star- fish, like that
which I have described, to possess
a long flexible column, the base of
which is attached to a rock, we
shall have a correct idea of the
general character of the crinoi'dea,
or lily-shaped animals." Prof.
Buckland states, " successions of
strata, each many feet in thickness,
and many miles in extent, are often
half made up of the calcareous
skeletons of encrinites." The en-
crinite differs from the pentacrinite,
another genus of the same order, in
having the bones of its column
circular, or elliptical, whereas those
of the pentacrinite are angular or
pentagonal. In the encrinites mo-
niliformis, a species of encrinite,
Mr. Parkinson states the upper
part of the skeleton to consist of
nearly 27,000 ossicula, or small
bones. Fossil encrinites are so
various that they have been divided
into several subgenera, according
to the formation of the central body.
E'NCRINITES MONILIFOBMIS. The lily
encrinite, or bead columned true
lily-shaped animal. A species of
the genus encrinites. Its specific
characters are thus described by
Miller : "A crinoidal animal with
a column formed of numerous round
joints, alternately, as they approach
the pelvis, larger and smaller, be-
coming subpentangular when nearly
in contact with it. On the pelvis,
formed of five pieces, adhere later-
ally the first series of costa?, on
which the second series of costse is
placed, succeeded by the scapulae
from which the ten tentaculated
arms or fingers proceed. Animal
permanently affixed by exuded
indurated matter. The encrinites
moniliformis has hitherto been
found only in the muschelkalk of

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the new red sandstone group, and
principally in Lower Saxony.

ENCRINI'TAL. Containing the remains
of encrinites. The Derbyshire en-
crinital marble is formed of the
fossilized remains of the crinoidea,
cemented together by carbonate of
lime.

ENCRI'NUS. A genus of the order
Pedicellata, class Echinodermata,
in Cuvier's arrangement.

"The characters of this genus/'
says Pidgeon, "may thus be given :
a stelliform or radiated body, com-
posed of five principal rays, sub-
divided into three or four articulated
branches, pinnated in their entire
length, presenting, at the upper
convave surface, a series of pores.
The body is supported at its ex-
tremity by a long stem, vertical,
polygonous, and articulated, and
furnished in its length with a
variable number of verticillae,
composed of five small simple
branches, equally articulated, and
probably adherent to submarine
bodies."

E'NDOCARP. (from ei/eW, within, and
/ca/>7ro9, fruit, Gr.) The stone or
shell of certain fruits is called the
endocarp, as in the peach, cherry,
&c. ; the outer skin the epicarp ;
the fleshy substance, the sarcocarp.

ENDOGE'NS. The fourth class of the
vegetable kingdom, comprising,
Glumiferae, PetaloideaB, and Die-
tyogense.

ENDOGENOUS. Plants are called en-
dogenous (from two Greek words,
evSov and ryivofiai) the growth of
whose stems takes place by addition
from within, while those whose
growth takes place by addition from
without are named exogenous. The
ferns and equisetacea3 are endo-
genous plants.

ENDOGENI'TES ECHINA'TUS. The name
assigned by M. Brongniart to the

fossil trunk of a tree, nearly four
feet in diameter, obtained from the
calcaire grossier at Yaillet, near
Soissons.

ENDOGENI'TES EEO'SA. A fossil plant
discovered by Dr. Fitton at Hast-
lings, imbedded in clay. The
stems, when cut and polished,
exhibit the monocotyledonous struc-
ture, and were considered related
to the palms. It occurs in the
strata of Tilgate forest. A small
specimen exhibiting that very pe-
culiar eroded appearance of the
exterior, which its specific name
denotes, is beautifully figured in
Dr. MantelPs Geology of the South-
East of England.

Dr. Fitton thus describes some
specimens of this fossil, "all the
specimens lay with their longer
diameter and their flatter surfaces
in the horizontal position. Their
appearance, when first uncovered
by the removal of the rock above,
was that of elongated and flattened
elliptical bodies, tapering at both
extremities. They consist of two
distinct portions ; a stony nucleus,
of a dark brownish grey colour,
with a very slight tinge of purple ;
and a crust or case, in the state of
lignite, which has externally a
nearly uniform surface, and varies
in thickness from about one tenth
to half an inch. The size of the
different specimens varies consider-
ably. The largest that I saw in
its place must have been in the
whole full nine feet long The
width in the middle was 12 inches,
and the greatest thickness four
inches. The original form of this
vegetable was probably cylindrical;
and that shape is still retained in
a large specimen of a nucleus from
Tilgate Forest, now in the British
Museum." Geological Events.

ENDOSI'PHONITE. (from evSov, and
ffttywv, Gr.) A cephalopod, found
in the Cambrian rocks. The si-
phuncle is ventral, differing therein

END

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from the ammonite, in which it is
dorsal, and from the nautilus, in
which it is central.

ENDOSKE'LETAL. Having its skeleton
within.

E'NNEAGON. (from eWea, nine, and
ryuWa, angle, Gr.) A polygon with
nine faces.

ENNEAPE'TALOTTS. (from eWeo, nine,
and TTGTaAoi/, a petal, Gr.) In bo-
tany, a corolla having nine petals.

E'NSIFORM. (ensiformis, Lat.) Sword-
shaped; two-edged; tapering to-
wards the point like a sabre. In
botany, applied to two-edged leaves,
slightly convex on both surfaces,
and gradually tapering to a point
from the base to the apex.

ENTI'RE. (entier, Fr. inUro, It.)
Whole ; undivided ; complete in all
its parts. In botany, a term
applied to leaves when the margins
are devoid of notches, serrations, or
incisions. In conchology, when a
shell is whole and undivided,
neither interrupted nor intermar-
ginated, it is termed entire.

ENTOMO'IDA. The third sub-kingdom
of the animal kingdom, called also
Diplo-gangliata. " This sub-king-
dom," says Prof. Grant, " is chiefly
composed of articulated animals
with articulated members, the
insects of Linnaeus, which have an
elongated, segmented form of the
trunk, with tubular jointed organs
of motion symmetrically disposed
along its sides. Their exterior
covering is more consolidated, and
generally contains phosphate of
lime. Some respire by branchiae,
others by ramified tracheae, and
others by pulmonary sacs. Most
are active, carnivorous, and pre-
daceous." This sub-kingdom com-
prises the following classes, namely,
Myriapoda, Insecta, Arachnida,
and Crustacea.

ENTO'MOLITE. (from eWoytta, an insect,
ans A/tfos, a stone, Gr.) A fossil

insect; a petrified insect. These
are found either in amber or in
fossil stones.

ENTOMOLI'THUS PARADO'XUS. The name
given, erroneously, at one time to
fossil trilobites. Fossil trilobites
were long confounded with insects,
under the name of entomolithus
paradoxus ; after many disputes,
their place is now established in a
separate section of the class Crus-
tacea.

ENTOMO'LOGY. (from eWo/*,a, and
Aoryos, Gr.) That part of the
science of zoology which treats
exclusively of insects, of their his-
tory and 'habits; that branch of
natural history which treats of in-
sects. The object of entomology is,
to investigate the nature of insects ;
its design is to show how the in-
sect is organised and formed, and
why it was obliged to adopt this
particular conformation and inter-
nal structure; and, when this is
accomplished, it proceeds to the
generalisation and development of
the various vital phenomena ob-
servable in the class. Its view,
however, is not limited to show
the mere general form of the body
of the insect, but it also displays
how this general form varies in the
several orders of insects, and how
far this general transformation and
change may extend, without de-
struction to its identification.

ENTOMOSTO'MATA. In the concho-
logical system of De Blainville, the
entomostomata form the second
family of Siphobranchiata, and
include many genera, as the buc-
cinum, dolium, cerithium, eburna,
and other univalves.

ENTOMO'STRACON. i (from
ENTOHO'STRACA PL. j an insect,
and oaTpaicov, a shell, Gr.) Shelled
insects. In Cuvier's arrangement
the entomostraca form the second
section of Crustacea. Entomos-

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traca are both dentated and eden-
tated ; they are mostly microscopic,
they are without exception aquatic,
and they mostly, though not with-
out exceptions, inhabit fresh water.
This order of crustaceans has the
head rarely, if ever, distinct from
the thorax, but provided with
antennae. Feet always distinct.
Animals undergoing metamorpho-
sis. Mr. Rupert Jones first noticed
the occurrence of Entomostraca in
the Permian system of England.
During the Permian period, the
prevailing forms of Entomostraca
seem to have belonged to two
groups, to Bairdia, and to an un-
determined genus. The list of
Permian entomostraca is now
rather extensive ; the Permians of
Durham possess a list of 21 species,
13 of which are peculiar to them.
Five species are peculiar to Ger-
many, and six to Russia.

ENTQMO'TOMY. (from eWo/*a, an
insect, and TG^J/W, to cut, Gr.)
The dissection of insects, by which
we learn their internal construc-
tion, and become acquainted with
the form and texture of their
organs.

ENTOZO'A. (from eVros and £an), Gr.)
Intestinal worms.

E'NTEOCHAL. (from entrochite.) Re-
sembling an entrochite j containing
entrochites.

E'NTROCHITE. (from eV and i-po^os,
Gr.) Wheel-stone ; a name given
to the broken stems of fossil en-
crinites. Some beds of mountain
limestone are almost entirely com-
posed of broken stems and branches
of encrinites, frequently called
entrochites. The detached verte-
bra of the radiaria are known
by the name of trochitaB ; and
when several are united together,
so as to form part of a column, the
series is termed an entrochite. The
perforations in the centre of the
vertebra afford a facility for
stringing them as beads, from

which, in ancient times, they were
used as rosaries, and in the northern
parts of England they still continue
to be known under the name of
St. Cuthbert's beads.

(from j]u><$, aurora, and
os, recens, because, as Sir C.
Lyell observes, the very small
proportion of living species con-
tained in these strata indicates
what may be considered the dawn,
or first commencement, of the
existing state of the animate cre-
ation.) M. Deshayes and Sir C.
Lyell, have proposed a fourfold
division of the marine formations
of the tertiary series, founded on
the proportions which their fossil
shells bear to marine shells of
existing species. To these di-
visions Sir C. Lyell has, with the
soundest judgment, applied the
terms Eocene, Miocene, Older Plio-
cene, and Newer Pliocene, and well
would it be for the advancement of
geology, if its nomenclature were,
in all instances, derived from
some universal language. In fully
explaining the meaning of these
terms, I shall borrow largely from
Sir C. Lyell's Principles of Geology.
In proportion as geological investi-
gations have been extended over a
larger area, it has become necessary
to intercalate new groups of an age
intermediate between those first
examined; and we have every
reason to believe that, as the
science advances, new links in the
chain will be supplied, and that the
passage from one period to another
will become less abrupt. All those
geological monuments are by Sir
C. Lyell called tertiary, which are
newer than the secondary forma-
tions, and which, on the other
hand, cannot be proved to have
originated since the earth was in-
habited by man. All formations,
whether igneous or aqueous, which
can be shewn, by any proofs to be
of a date posterior to the intro-

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duction of man will be called
recent. The European strata may
be referred to four successive periods,
each characterised by containing a
very different proportion of fossil
shells of recent species. These
four periods will be called, Newer
Pliocene, Older Pliocene, Miocene,
and Eocene. In the older groups
we find an extremely small number
of fossils identifiable with species
now living ; but as we approach
the superior and newer sets, we
find the traces of recent testacea in
abundance. The latest of the four
periods before alluded to, is that
which immediately preceded the re-
cent era. To this more modern period
may be referred a portion of the
strata of Sicily, the district round
Naples, and several others. They
are characterised by a great pre-
ponderance of fossil shells referable
to species still living, and may be
called the Newer Pliocene strata.

Out of 226 fossil species brought
from beds belonging to this di-
vision, M. Deshayes found that not
fewer than 216 were of species still
living, ten only being of extinct or
unknown species. Nevertheless,
the antiquity of some Newer Plio-
cene strata of Sicily, as contrasted
with our most remote historical
eras, must be very great, embracing
perhaps myriads of years. There
are no data for supposing that there
is any break, or strongly marked
line of demarcation, between the
strata of this and the recent epoch ;
but, on the contrary, the monu-
ments of the one seem to pass
insensibly into those of the other.

The Older Pliocene strata contain
among their fossil shells a large pro-
portion of recent species, amounting
to nearly one-half. Thus out of
569 species examined from Older
Pliocene strata in Italy, 238 were
found to be still belonging to living,
and 331 to extinct, or unknown,
species.

The next division of the marine
formations of the tertiary period is
the Miocene, from fieiwv, minor,
and Kaivos, recens. In this division
a small minority, less than eighteen
per centum, of fossil shells being
referable to living species. From
an examination of 1021 shells of
the Miocene period, M. Deshayes
found 1 76 only to be recent. As
there are some fossil species which
are exclusively confined to the
Pliocene, so are there many shells
equally characteristic of the Miocene
period. The Miocene strata are
largely developed in Touraine, and
in the South of France, near Bour-
deaux ; in Piedmont ; in the basin
of Vienna, and other localities.

The oldest division of the marine
formations of the tertiary period is
the Eocene, the derivation of which
term is given at the commencement
of this article. To this era the
formations first called tertiary, of
the Paris and London basins, are
referrible. The total number of
fossil shells of this period known
when the tables of M. Deshayes
were constructed, was 1238, of
which number 42 only are living
species, being at the rate of three
and a half per centum. Of fossil
species, not known as recent, forty-
two were found to be common to
the Eocene and Miocene epochs.
Of the present geographical distri-
bution of those recent species which
are found fossil, in formations of
such high antiquity as those of the
London and Paris basins, there is
much of great interest and import-
ance. Of the forty-two Eocene
species, which occur fossil in Eng-
land, France, and Belgium, and
which are still living, about one-
half now inhabit the seas within,
or near the tropics, and almost all
the rest are inhabitants of the more
Southern parts of Europe.

The heat of European latitudes
during the Eocene period, does not

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seem to have been superior, if
equal, to that now experienced
between the tropics.

The English Eocene deposits are
generally conformable to the chalk,
being horizontal where the beds of
chalk are horizontal, and vertical
where they are vertical; so that
both series of rocks appear to have
participated in nearly the same
movements.

As a summary of the preceding,
the numerical proportion of recent
to extinct species of fossil shells, in
the four different tertiary periods,
is as follows : —

Newer Pliocene period 90 to 95
Older Pliocene period 35 to 50
Miocene period . . 18
Eocene period . . 3J
per centum of recent fossils.

In the British Islands, strata
belonging to the Eocene system
are found only in the South Eastern
parts of England, namely, in the
country round London, in the
south of Hants, and in the north of
the Isle of Wight. The Eocene
system consists of the following
groups, Lower Eocene, containing
the Plastic Clay, the "Woolwich
Beds, Thanet Sands, London Clay,
and Bognor Rock, all fresh- water.
The Middle Eocene, the Bagshot
and Bracklesham Sands, the Barton
Clays, marine, and the Headon,
fluvio - marine and fresh - water.
The Upper Eocene, containing the
St. Helen's Sands, the Bembridge
Sands, and the Hampstead series,
principally fresh-water. Of the
Pleiocene group there is a sub-
division, named Pleistocene, or the
maximum proportion of the recent,
containing from 90 to 95 per cent,
of the recent, and after these has
been added the "Post Pleiocene,
or Quarternary," in which all the
fossil shells are still found living,
though not perhaps in the imme-
diate neighbourhood of the places
where they are found fossil.

EPHE'MEBA. (c^fiepla, ex. €W et
yijiepa, Gr.) Insects, so called
from their short term of life in
their perfect state. Their body is
extremely soft, long, tapering, and
terminated posteriorly by two or
three long and articulated seta?.
The antenna? are very small and
composed of three joints, the last
of which is very long, and in the
form of a conical thread. The
ephemera usually appear at sun-
set, in fine weather, in summer
and autumn, along the banks of
rivers and lakes. The continuation
of their species is the only function
those animals have to perform, for
they take no food, and frequently
die on the day of their metamor-

Ehosis. In another condition, as
irvae, their existence is much
longer, extending from two to
three years. In this first state
they live in water.

E'PICABP. (from fVt, upon, and *ra/j-
7T09, fruit, Gr.) In botany, the
outer skin of fruits is called the
epicarp; the fleshy substance, or
edible portion, is termed the sarco-
carp, and the stone is called the
endocarp.

EPIDE'RMAL. } Composed of epidermis;

EPIDE'BMIC. ) relating to the epi-
dermis ; resembling the epidermis.

EPIDE'BMIS. (eirideppls, Gr. epidermis ,
Lat. epiderme, Er. epidermide, It.)
The scarf-skin, or cuticle, of animals.
In conchology, the outer skin or
cuticle, with which the exterior
surface of many of the univalve and
bivalve shells is covered. It is
membranaceous, and resembles the
periosteum which covers the bones
of animals. The skin seems to be
formed entirely by the animal, and
is always met with in some species,
and never in others; those shells
with a ragged surface have almost
always an epidermis. In some it is
laminated, velvety, fibrous, or
rough; in others it is thin and
pellucid, allowing the colours of the

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shell to show through it. It often
falls off of its own accord, and
without any injury to the surface
of the shell ; the beauty of many
shells is hidden by this outer coat.
— In botany, the outward covering
of plants : every plant is covered
by a skin, or membrane, analogous
to the scarf-skin that covers animal
bodies; this epidermis varies in
thickness, being extremely delicate
and diaphanous on some parts of a
flower, and very thick, hard, and
coarse, on the trunks of many trees.

EPIDI'DYMIS. (eVt&dvyue?, from eV*,
and^v/tos-, Gr.) A body principally
composed of minute, tender, elas-
tic tubes, intricately convoluted,
termed tubuli seminiferi, and placed
at the outer and back part of the
testis.

E'PIDOTE. The Prismatoidischer Au-
gitspath of Mohs, and Pistazit or
Pistacite of Werner; the thallite
of Lemetherie; akanticone of Dan-
drada; delphinite of Saussure;
glassyactinolite of Kirwan; aren-
dalit of Karstein ; glassiger strahl-
stein of Emmerling ; and la rayon-
nante vitreuse of Brochant. The
above long array of names assigned
to one mineral by various mineral-
ogists, affords a striking illustration
of the evils arising from ill-arranged
nomenclature, and adds greatly to
the perplexity of the student. A
mineral of a green or grey colour ;
passing on the one hand into
blackish-green, on the other, into
dark olive-green, oil-green, and
siskin-green. It occurs regularly
crystallized, in granular, prismatic,
and fibrous concretions, and is said
to derive its name from the Greek
word eTJdiSwfjLi, from an enlarge-
ment of the base of the prism in
one direction : it is also found
massive and granular. Its lustre
is shining externally, and vitreous;
internally, glistening and resinous.
It is hard, brittle, frangible, and
scratches glass. Specific gravity

3.42. Hardness = 6.0— 7.0. The
primary crystal is a right oblique
angled prism, of about U5°30' and
6 4° 30'. It cleaves with brilliant
surfaces, parallel with the lateral
planes of the prism. Before the
blow-pipe it melts into a dark
brown or blackish scoria ; and this
property, according to Saussure, is
very characteristic. Two varieties
of epidote have been separated ;
one has been named zoisite by
Jameson, after Baron Von Zois, its
discoverer; the other, skorza, by
Brochant. It is found, principally,
in primary rocks, and in many
parts of Scotland, as well as in
England, Norway, France, &c. It
consists of silica 37*0, alumina
27-0, lime 14'0, oxide of iron 17*0,
oxide of manganese 1/5. There
are many varieties.

EPIGA'STRIC. (from eVt, above, and
ryaffTyp, the belly, Gr. tpigastrique,
Er.) Belonging to the upper part
of the abdomen, or epigastric region.

EPIGA'STRIUM. (eTTL^aarpiov, Gr. epi-
gastrium, Lat. epigastre, Er.) The
upper part of the abdomen or belly.

EPIGLO'TTIS. (epiglottis, Lat. epiglotte,
Er. e7ri<y\,wffffl$, vel eVtryXwTTts, Gr.
membranacartilaginosarotunditatis
oblongee gutturi claudendo et rese-
rando.) One of the five cartilages
of the larynx, situated above the
glottis, whose use is to close the
glottis during the act of swallowing,
and thereby to prevent the passage
of food into the trachea, or wind-
pipe.

EPIPHYLLOSPI'BMOUS. (from eV«, <pv\-
\ov and ffTrepjLia, Gr.) A term in
botany, applied to plants bearing
their seeds on the back part of their
leaves; ex. the ferns.

EPIOLI'TIC. A term proposed to be
given to certain rocks by Professor
Catullo. Sir R. Murchison says :
"I hold that the rocks which Pro-
fessor Catullo has termed epiolitic,
when separated from the neoco-
mian, are simply the representatives

E P I

E Q U

of the Oxfordian group," Profes-
sor Catullo divides the Epiolitic
group, which consists of lime
stones, into the upper and lower,
the former composed of the red
lime stones of the Jura range, the
lower, the Epiolitic lime stone of
the Venetian Alps.

EPI'PHYSIS. (eV/<?W/s, from eVt0va>f
Gr.) A process of bone attached
to a bone, but not being a part of
the same bone, as in the case of
apophysis.

Epi'PLOON. (eVfVXooz/, from liriirKeia,

Gr. epiploon, Fr.) The omen turn,
or caul ; that membranous expan-
sion which hangs from the bottom
of the stomach and covers the
intestines.

EPIZOO'TIC. (from ITTI and £woz>, Gr.)
Containing animal remains, as epi-
zootic hills, or epizootic strata.

E'POCH. (eVo^, Gr. epocJia, Lat.
epoqm, Fr. epoca, It.) A term
literally signifying a stop, a fixed
point of time, from which succeed-
ing years are numbered; the period
at which a new computation, or
reckoning, is begun.

EQUA'TOR. (equateur, Fr. cequator,
Lat. equatore, It.) A great circle
of the sphere, equally distant from
the two poles of the world, or
having the same poles with those
of the world. It is called the
equator, because when the sun is
in it, the days and nights are
equal ; whence also it is called the
equinoctial. Every point of the
equator is a quadrant's distance
from the poles of the world ;
whence it follows, that the equator
divides the spheres into two hemi-
spheres, in one of which is the
northern, and in the other the
southern pole.

EQUATO'BIAL. Pertaining to the
equator: the equatorial diameter
of our planet exeeds its polar
diameter by about 26 miles; the
length of the equatorial diameter

being 7927 miles, that of the polar
7900.

EQUIA'NGULAR. (from aquus and an-
ffulus, Lat. equiangule, Fr. equian-
golo, It.) A figure whose angles
are all equal; consisting of equal
angles ; having equal angles.
EQUISETA'CE^. (from equisetum, horse-
tail.) These plants are known in
this country as the horse-tail of
our ditches. EquisetaceaB are found
fossil and recent. H. Ad. Brong-
niart has, in his "Histoire des
VSgetaux Fossiles," divided fossil
equisetacea3 into two genera ; the
one exhibits the characters of living
equiseta, and as a fossil is rare;
the other differs greatly in its form,
frequently attaining an immense
magnitude; these last have been
arranged under the distinct genus
Calamites. Equisetaceae are found
from Lapland to the Torrid Zone ;
the species are most abundant in
the temperate zone : as we approach
a more frigid temperature, they
diminish in size and abundance,
and in the warm and humid re-
gions of the tropics they acquire
their greatest magnitude.
EQUISETUM. (Lat. A genus of the order
Filices, belonging to the Crypto-
gamia class of plants.) Horse-tail.
Of this genus there are numerous
species. The equisetum fluviatile
of our marshes is the largest of all
the species, growing sometimes to
the height of three feet, and nearly
an inch in diameter. It has a
succulent, erect, jointed stem, with
attenuated foliage surrounding the
joints in whorls. In the coal
measures, remains of the equiseta
are in great abundance, and occur
of a magnitude quite unknown at
the present day, some of the stems
being fourteen inches in diameter.
M. Ad. Brongniart enumerates
twelve species of calamites and
two of equiseta found in strata of
the carboniferous series. Equiseta
occasionally occur in the Wealden

an

[ 162]

E K

strata, and where they are found
they are abundant.

EQUISE'TUM LYELLII. The name given
by Dr. Mantell to a distinct species
of equisetum, found in the grey and
blue grit and limestone at Pounce-
ford, in honour of Sir C. Lyell.
"When perfect, it probably attained
a height of two feet or more.

EQUIVALENT, (from aequus and valens,
Lat.) In geology, where one bed
supplies the place of another which,
in that situation, is wanting, such
bed is called the equivalent of the
wanting bed. "When a stratum
suddenly terminates, and its place
is supplied by a stratum of a dif-
ferent character, the latter is called
the equivalent of the former. The
equivalents of compound substances
are the sums of those of their ele-
ments ; thus the equivalent of water
is (8 -fl = 9).

E'auiVALE. (from aquus and valva,
Lat.) In conchology, when the
shells of bivalves are formed exactly
alike, as regards their length, width,
depth, &c. The shells of mya, solen,
tellina, &c., are generally of the
kind called equivalve, while those of
ostrea, pinna, &c., are inequivalve.

E'RA. (<zra, Lat. Written frequently
<era.) A particular account and
reckoning of time and years, from
some remarkable event. Webster
quoting from some encyclopaedia,
says, " it differs from epoch in this;
era is a point of time fixed by some
nation or denomination of men;
epoch is a point fixed by historians
and chronologists. The Christian
era began at the epoch of the birth
of Christ."

EBE'CTILE. (from erigo, Lat.) A
tissue peculiar to certain parts of
the body, as the nipple, &c.

EBE'CT. (erectus, Lat.) In botany,
leaves are so called when they form
a very acute angle with the stem.
The term is also appiiecl to branches
rising in an upright direction, to
petioles rising nearly perpendi-

cularly; and to flowers and pedi-
cles rising perpendicularly.

E'BINITE. A name given to a species
of native arseniate of copper, from
its having been discovered in Ire-
land. It is of an emerald-green
colour; its constituent parts are
oxide of copper, arsenic acid, alu-
mina, and water.

EEO'SE. | (erostis, Lat.) Jagged;

EBO'SUS. ) applied to leaves very
irregularly cut or notched, and
having the appearance of being
gnawed or eaten by insects.

EBO'TYLUS. A genus of insects, be-
longing to the Vivalpi, or the
seventh family of the Tetramera.
In the Erotyli the intermediate
joints of the antennae are almost
cylindrical, and the club, formed
by the last ones, is oblong; the
interior and corneous division of
their maxilla is terminated by two
teeth. They are peculiar to South
America.

ERLNA'CEUS. (Lat.) The hedgehog.

EBPETO'LOGY. (from epTrerb? and XoV/os,
Or.) That branch of natural his-
tory which treats of the structure,
habits, &c., of reptiles.

EBRA'TIC BLOCK GROUP. One of the
sub-divisions of detrital deposits.
Professor Phillips observes, " In
the British islands, very consider-
able tracts of country have been
traversed, since the land had its
present general aspect of hill and
dale and was inhabited by large
quadrupeds, by currents of water
due to some unknown cause, which
transported rock masses with so
great a degree of force, to points
so elevated, in such directions, and
at such distances, that we cannot
avoid feeling extreme astonishment,
and look around in disappoinment
on the physical processes now at
work on the earth, for anything
similar. But it is only in particular
tracts that the magnitude of the
transported rocks is such as to
deserve the name of erratic Uocfo.

E R U

L

It appears to be certain that, in the
dispersion of boulders, the present
physical configuration of the neigh-
bouring regions had great influence ;
they are found to descend from the
Cumbrian mountains northward in
the vale of Eden to Carlisle, east-
ward to the foot of the Penine chain,
southward by the Lune and the
Kent to the narrow tract between
Bolland Forest and the bay of
Morecambe ; and from the vicinity
of Lancaster they are traced at
intervals through the comparatively
low country of Preston and Man-
chester, lying between the sea and
the Yorkshire and Derbyshire hills,
to the valley of the Trent, the
plains of Cheshire and Staffordshire,
and the vale of the Severn, where
they occur of great magnitude." —
Phillips1 Treatise on Geology.

ERUCTA'TION. (eructatio, Lat. Eructa-
tion, Fr.) A violent belching forth
of wind or other matter, as from a
volcano or geyser.

EET/GINOUS. (from terugo, Eat. eru-
gineux, Fr. ruginoso, It.)

1. Of the nature of copper.

2. Of a bright green colour, in-
clining to blue.

EEY'CINA. An equivalved, inequi-
lateral, transverse bivalve. The
hinge-teeth two, diverging up-
wards, with a small intermediate
pit; the lateral teeth compressed
and oblong. The cartilage inserted
in the hinge-pit. Lamarck is of
opinion that the shells of this genus
exist only fossil, and enumerates
eleven species found in the environs
of Paris. He places them in the
family Mactracea.

ESCA'LOP. | Commonly called scollop.

ESCA'LLOP. j A bivalve, whose shell
is regularly indented.

E'SCAE. The name given to certain
glacial deposits, chiefly consisting
of pebbles of carboniferous lime-
stones, heaped sometimes into
ridges from 40 to 80 feet high, and

13 ] ESS

. from one to twenty miles long, these

are called Escars.
ESCA'EPMENT. (escarpement,T?i.) The

steep face of a ridge of high land ;

the escarpment of a mountain range

is generally on that side which is

nearest to the sea.
ES'CHAEA, (eschar a, Lat.)

1. Fishes which are said to chew
the cud.

2. In Linnaeus' s arrangement, es-
chara forms the fifth order of
Zoophytes, each polypus being con-
tained in a calcareous or horny
shell, without any central axis.

3. A genus of zoophytes, ten species
of which have been named by
Gold fuss as occurring in the cre-
taceous group, in the neighbourhood
of Maestricht.

ESCHABI'NA. A genus of corals thus
named by Milne Edwards.

ESO'PHAGUS. (from OKD and (frayeiv,
Gr. esophage, Fr. esdfago, It.) The
canal, or passage, leading from the
pharynx to the stomach, and through
which the food passes from the
mouth to the stomach. It is also
written esophagus.

E'sox (Lat.) The pike, a genus of
fishes of the order Abdominales.
The esox has small intermaxillaries
furnished with little pointed teeth
in the middle of the upper jaw, of
which they form the two-thirds,
those on the sides of the jaw being
edentated. The vomer, palatines,
tongue, pharyngeals, and rays of
the branchiae, bristled with teeth
resembling those of a carp. The
dorsal fin is exactly opposite to the
anal.

ESSENTIAL CHAEACTEE. That single
circumstance which serves to dis-
tinguish a genus from every other
genus.

E'SSONITE. Another name for cin-
namon-stone. A variety of dode-
cahedral garnet, of an orange
yellow, or hyacinth colour. The
finest are brought from Ceylon.
See Cinnamon stone.

E T H

[ 164 ] E X C

ETHE'EIA. A genus of large in-
equivalve molluscs belonging to the
family Ostracea. They differ from
the ostrese in having two elongated
muscular impressions in each valve,
which are united by a slender
palleal impression. The animal is
not known to produce a byssus.

E'THMOID. (from ^fyto<?, a sieve, and
ei£os, like, Gr.) A bone of the
nose to which the name ethmoid
has been given from its being
cribriform, or perforated like a
sieve, for the passage of the olfac-
tory nerves.

E'TITE. See Elites.

E'TTUS. A genus of crustaceans,
some species of which have been
discovered in the gait.

EUCHYSI'DEBITE. A mineral occurring
crystallized. Primary form, an
oblique rhombic prism of the same
cleavage and measurements as
pyroxene. Colour, brownish-black.
Lustre, vitreous; nearly opaque.
Specific gravity 3 -3 4, hardness 6
to 6-5. Streak, yellowish-grey.
Fracture, imperfect conchoidal.
Found in Norway.

EU'CLASE. (from ei>, well, and K\awt
to break, Gr.) The Prismatischer
Smaragd of Mohs ; Prismatic Eme-
rald. This stone has obtained its
name from the ease with which it
is broken. It is a rare and beau-
tiful mineral, and was brought
first from Peru by Dombey ; it was
at first confounded with the eme-
rald, in consequence of its green
colour. The primitive form of its
crystals is a rectangular prism,
whose bases are squares. It is of
sufficient hardness to scratch
quartz. Its constituents are silica,
alumina, glucina, and the oxides of
iron and tin. Euclase has hitherto
only been found crystallised. Spe-
cific gravity 3*06, hardness = 7*5
It is transparent, and possesses
strong double refraction. Before
the blow-pipe it first loses its

transparency, and then fuses into
a white enamel.

EUDI'ALITE. A mineral of a brown-
ish-red colour, having an octohedral
cleavage.

E'UDOSIPHONITES. The same assigned
by Professor Ansted to a genus of
ammonites. See Aymenia.

EUGE'JSTA GEINITES. (So named from
the Eugenia caryophyllata, or clove
tree, the unripe fruit of which it
resembles, and Kpivov, a lily.) A
genus of fossil crino'idea, six species
of which have been determined by
Goldfuss and Munster as occurring
in the oolitic group.

EUKAI'EITE. Cupreous seleniuret of
silver, consisting of silver 39, se-
lenium 26, copper 23, alumina 8.

ET/LISITE. A mixture of olivine-like
oxide of iron, green augite, and
brownish-red garnet. — Jukes.

EUO'MPHALUS. A univalve uncham-
bered fossil shell, found in the
mountain lime-stone.

EU'PHOTIDE. ) Names given by the

EU'PHOTITE. j French mineralo-
gists to Saussurite. A green stone
in which the hornblendic mineral
is diallage, and the feldspar labra-
dorite.

EU'PODA. The name given in Cuvier's
"Begne Animale" to the fifth
family of Tetramerous Coleoptera ;
Eupoda comprises two tribes, Sag-
rides and Criocerides.

EUEYPTE'EIDA. An order of crusta-
ceans, comprising eurypterus and
pterygotus, found fossil only.

EU'EIIE. White-stone, the weiss-
stein of Werner. A variety of
granite in which feldspar predomi-
nates, and named Eurite by the
French mineralogists. It occurs
in beds, in common granite, in
Cornwall. In its most compact
form, it becomes a porphyry, and
is closely allied to volcanic rocks
in Auvergne; felspathic granite. —
JBakewell.

EXCE'BN. (excerno, Lai.} To excrete;

E X 0

[165]

A C

to separate and emit through the
pores.

E'XOGEN. Exogens are plants which
have a pith in the centre of their
stems, not descending into the roots;
or having their woody system sepa-
rated from the cellular, and ar-
ranged in concentric zones. They
increase by additions to the outside
of their wood, as the name implies.

EXOGENOUS, (from e£w and fyeiWu?,
Gr.) Plants in which the growth
takes place by additions from with-
out, or by external increase. Exo-
genous trees augment, both in height
and diameter, by the successive
application, externally, of cone
upon cone of new ligneous matter,
so that if we make a transverse
section near the base of the trunk,
we intersect a much greater number
of layers than nearer to the summit.
"We can ascertain the age of an oak
or a pine, by counting the number
of concen trie rings of annual gro w th,
seen in a transverse section near
the base, so that we may know the
date at which the seedling began
to vegetate. The Baobab- tree of
Senegal is supposed to exceed al-
most every other in longevity.
Adanson was of opinion that one
which he measured, the diameter
of which was thirty feet, had at-
tained an age of 5150 years.

EXO'SSATED. (exossaius, Lat.) De-
prived of bones.

EXO'SSEOTTS. (from ex and ossa, Lat.)
Destitute of bones; animals not

EXOSTO'SIS. (from e£ and oa-reov, Gr.)
A diseased growth of bone.

EXO'TIC. (exoticus, Lat, ll-ionico*, Gr.
exotique, Fr. esotico, It.) In botany,
plants not natives of the countries
in which they are cultivated.

EXPLANA'BJA. A genus of stony
polypifers, fixed, expanded in a
free, foliaceous, undulated, or con-
voluted and sublobated membrane,
with one stelliferous surface.

EXTE'NSOR. (from extendo, Lat. exten-
seur, Fr.) The name of such
muscles as extend or straighten
the parts, and serve as antagonist
muscles to the flexors.

EXU'VI^J. (Lat.) Cast shells; cast
skins; organic remains.

EXTT' VIABLE. That may be cast or
thrown off, as the skeletons of
articulated animals.

EYED AGATE. The name given to
such specimens of agate as have
their coloured zones arranged in
concentric circles. The lapidary,
by cutting and rounding these
agates in a particular manner, is
able to produce a striking resem-
blance to the eyes of certain animals.

FAB'ACEOUS. (fabaceus, Lat.) Of the
nature of a bean; resembling a bean.

FABOIBEA. The name given to a
genus of fossil seeds found in the
London clay, and resembling our
garden beans, whence the name.
Twenty-five species are described
by Mr. Bowerbank.

FACE. (face, Fr. faccia, It. fades,
Lat.) One of the figures which
compose the superficies of a body ;
the surface which presents itself to
the sight. Polyhedrons have se-
veral faces ; a cube has six faces.

FA'CET. (facetta, It. facette, Fr. I'un
des cotes d'un corps qiri a plusieurs

F A C

[ 166]

F A L

petite cdtes.) A superficies cut into
several angles.

FA'CTAL. (from fades, Lai. facial, Fr.)
Belonging to the face, as the facial
nerves, &c.

F'ACIAL ANGLE. An angle composed
of two lines, one drawn in the di-
rection of the base of the skull,
from the ear to the roots of the
superior incisores, the other from
that point to the superciliary ridge
of the frontal bone. The facial
angle of Camper was obtained by
drawing a line from the most pro-
minent part of the forehead to the
edge of the upper incisors, or front
teeth, and then, by making a basi-
lar line from the external aperture
of the ears to the lower edge of the
aperture of the nostrils, so as to
bisect the previous line. Camper
states this angle to be fifty-eight
degrees in the young Orang, seventy
degrees in the young Negro, and
eighty degrees in the European.
In consequence, however, of some
variations in the relative position of
the parts above mentioned, Cuvier
proposed, as a more certain mode
of ascertaining the facial angle, to
draw a basilar line parallel to the
floor of the nostrils, the angle
formed with which, by a facial line
drawn from the anterior convexity
of the forehead to the greatest pro-
minence of the sockets of the front
teeth, he states to be sixty-seven
degrees in the young Orang, seventy
degrees in the adult Negro, eighty-
five degrees in the adult European,
and ninety degrees in the European
child.

F^'CES. (fax, Lat. used plurally only.)
Excrement; sediment. The fossil
faeces of certain fishes are called
coprolites; the excrement of dogs
and wolves, album graecum ; of
mice, album nigrum.

FA'HLTJNITE. (from Fahlun, in Swe-
den, where it is found.) An earthy
mineral, called also Tricklasite ; it
occurs in masses, and in thin layers,

and is of a dark red -brown colour
and opaque. It consists of silex
46'74, alumina 26*73, magnesia
2-97, oxide of iron 5- 11, and water
12-5.

FAIRY-KING. In meadows and grass-
lands, circles of a different hue
from the surrounding grass are
often seen; these are commonly
called fairy-rings, from a vulgar
saying that at night fairies dance
thereon. The true cause of these
appearances, which have excited
the astonishment of many, is as
follows : they are external indica-
tions of the centrifugal growth of
the subterranean stems of certain
agarics, which, originally springing
from a common point, continually
spread outwards upon the same
place, the centres, or first formed
parts, perishing as the circum-
ference, or last formed parts, de-
velope themselves.

FAIET-STONE. A name sometimes
given to the echinite.

FA'LCATE. A figure formed by two
curves bending the same way, and
meeting in a point at the apex,
the base terminating in a straight
margin, resembling a sickle.

FALLING-STONE. } A meteoric body,

FALLING-STAE. j commonly called
an aerolite.

FA'LTTN. ffaluniere, Fr. assemblage de
coquilles Irisees, qu'on trouve en masse
d une certaine profondeur de terre.J
A provincial name given to some
shelly strata in the neighbourhood
of the Loire, and which resemble,
in their lithological characters, what
is denominated the crag. Thefaluns,
or marls of Tourraine and the Loire,
constitute an extensive formation of
marl beds, which are now admitted
to be of later date than the most
recent of the fresh-water beds in
the Paris basin. They are regular
depositions, formed during an epoch
of tranquillity, and subjected to
laws of which the action is con-
tinued on the present shores. The

FAB

[167]

FAS

great mass of fossil shells which
these beds contain, differ from those
of the Paris basin : in nearly 400
species, there are only about 20
identical with the Paris fossils.
The terrestrial and river shells are
in the same state of mineralization
as the marine shells. The bones of
the mastodon, rhinoceros, and hip-
popotamus, are in the same state of
preservation as those of whales, and
other cetaceous animals, with which
they are intermixed. They are
coated with marine polypi and
serpulse, which proves that they
were long covered by a tranquil
and stationary sea. These faluns
are distinct from the tertiary beds
of the Seine, and more recent than
any of them ; but they are them-
selves the lowest term of a new
system, more important, and more
extensive, than the formations of
the Paris or London basins, and
which has been continued to the
present epoch, during all the nu-
merous up-heavings of the ground,
the changes in the relative level of
seas and continents, and the suc-
cessive modifications of organic
beings.

FABCILITE. Farcilite is the prevailing
rock about Manresa in Spain.

FARI'NA. (Lat.) Meal; flour: in
botany, the pollen, or dust of the
anther. The pollen, or farina, is
contained in the anther. In dry
and warm weather the anther con-
tracts and bursts, when the pollen
is thrown out. From microscopic
observation we find each particle
of dust to be generally a membra-
nous bag, either round or angular,
smooth or rough, which on meeting
with any moisture instantly bursts
with great force, and discharges a
subtile vapour.

FA'RINOSE. In entomology, having
the surface covered with dust, re-
sembling flour, which the slightest
touch will remove.

FA'SCIA. (Lat.) The tendinous ex-

pansion of a muscle, inclosing others
like a band.

FA'SCIATED. Filleted, or enclosed with
a band.

FA'SCICLE. (fasiculus, a little bundle,
Lat.) A bundle, or little bundle :
applied to flowers on small stalks,
when many spring from one point,
and are collected into a close and
level bundle at the top; as the
sweet-william.

FASCI'CTJLAB. (fascicularis, Lat.) Uni-
ted, or growing together, in a clus-
ter, or tuft, as the larch, and some
species of pine; applied also to
roots, when many tubes proceed
from the same centre, shooting forth
in an elongated form.

FASI'CULATED. Arranged in small
bundles. In mineralogy when the
crystals are collected, as it were,
into bundles.

FASCIO'LA. The fluke- worm. A genus
of internal worm belonging to the
order Parenchymata, family Trema-
dotea. There are many species;
they are furnished underneath the
body, or at its extremity, with
organs resembling cupping-glasses,
by which they adhere to the viscera.
In this genus is included the Distoma
hepatica, or Fasciola Hepatica of
LinnaBus, which so infests, and is
so common in, the hepatic vessels
of sheep.

FASCIOLA'RIA . A subf usiform univalve,
channelled at its base, without any
projecting sutures, and having two
or three very oblique folds on the
columella. — Parh'nson.

FASCIOLI'TE. Asubcylindrical, shelly,
or bony body, about half an inch in
length, rather tapering at the ends,
and formed by the spiral arrange-
ment of perpendicular, concamer-
ated tubes, the tapering end of
which is obliquely and transversely
folded on that of the preceding one.
The tubes are seen to be distinct,
and, where the outer surface has
been removed, the concamerations
are perceived, resulting from the

PAS

interposition of very numerous and
minute septa, transversely disposed.
The tubes are placed perpendicularly
round the centre, and it appears that
round the first formed tube, or
chamber, successive increasing co-
lumnar tubes were disposed, fold-
ing over each other at their ends.
"Whether these several tubes were
internally connected with each other
or not, or whether the chambers
communicated, or not, with each
other, by a siphuncle, are questions
not yet clearly ascertained. Like
some of the nummulites, this body,
when polished, has more the ap-
pearance of bone than of shell, and
from this and other circumstances,
it seems to approximate nearer to
the nummulite than to any other
fossil.

FA'SSAITE. (from Fassa in the Tyrol.)
Called also Pyrgom. A mineral, a
dark-green variety of augite ; it is
also found in Scotland and Ireland,
in beds of primitive trap, limestone,
and magnetic ore.

FASTI'GIATE. j (fastigiatus, Latin.)
FASTI'GIATED. j Pointed; a term
applied to a stem, peduncles, umbel,
&c.

FAT OJJABTZ. ] (The Quartz hyalin
FETID QTJAETZ. ) gras of Haiiy.)
Quartz, both crystallised and mas-
sive, sometimes exhibits, when
fractured, a greasy polish on the
surface, equal to that which would
be produced by rubbing it with oil :
it sometimes, though not always,
gives out a fetid odour when
struck; from these two circum-
stances the above names have been
given to this variety.
FAULT, (faute, Fr.) A breaker
intersection of strata ; interruption
of the continuity of strata, with
displacement; the sudden interrup-
tion of the continuity of strata, in
the same plane, accompanied by a
crack or fissure, varying in width
from a mere line to several feet,
such fissure being generally filled

[ 168 ] F A U

with fragments, &c. Although the
two sides of a fault often come
into close contact, there is very
frequently a clayey substance in-
terposed which is impervious to
water ; and it rarely happens that
water on one side of a fault passes
to the other side. On the contrary,
the water is usually discharged
along the line of the fissure, par-
ticularly on mountain sides, in the
shape of springs. "When a fault
occurs in strata they are generally
either elevated or depressed, so
that in working a bed or vein there
appears to be a sudden termination
of it. Faults consist of fissures
traversing the strata, extending
often for several miles, and pene-
trating to a depth, in very few
instances ascertained; they are
accompanied by a subsidence of the
strata on one side of their line, or,
which amounts to the same thing,
an elevation of them on the other ;
so that it appears, that the same
force which has rent the rocks thus
assunder, has caused one side of the
fractured mass to rise, or the other
to sink. Of the extent of dis-
placement of strata some idea may
be formed from the following
statement; the old red sandstone
of the Fans, situated in South
Wales, is proved to have been
upcast to an extent of 700 feet.
Mr. Eald mentions that the great
south slip in the Clackmannanshire
coal field throws down the strata
1230 feet. If we suppose a thick
sheet of ice to be broken into
fragments of irregular area, and
these fragments again united, after
receiving a slight degree of irregular
inclination to the plane of the
original sheet, the re-united frag-
ments of ice will represent the
appearance of the component por-
tions of the broken masses, while
the intervening portion of more
recent ice represents the clay and
rubbish that fill the faults. In the

F A TJ

J

F E L

coal-fields, these faults operate as
coffer-dams, and are of the greatest
possible advantage. Faults are of
two kinds, true faults, and Symon
faults. When a stratum of coal
tapers away and disappears amid
the shales and sandstones, it is
locally termed a "Symon" fault.
See Symon Fault.

FA'UNA. (fount, Lat.) As the
plants peculiar to a country con-
stitute its flora, so do the animals
constitute its fauna ; the zoology
of a country.

FATTX. (Fr.) That portion of the
cavity of the first chamber of a
shell which may be seen by looking
in at the aperture.

FAVOSITES. A genus of foraminated
polypifers, resembling the honey-
comb in appearance, from which
circumstances the name has been
applied.

FAVTTLA'RIA. A genus of fossil plants.
Stem-furrowed ; scars of leaves
small, square, and of a breadth
with the ridges of the stem. In
the favularia, the trunk was
entirely covered with a mass of
densely imbricated foliage, the
bases of the leaves are nearly
square, and the rows of leaves
separated by intermediate grooves.
The genus is believed to be extinct,
but is found fossil in the coal
formation.

FEA'THERY. Plumose; applied to

plants furnished with lateral hairs.

FECU'LA. (from fax Lat. fecule, Fr.)

1. The sediment or grounds of any
liquid. The word fecula, says
JDr. Paris, originally meant to
imply any substance which was
derived by spontaneous subsidence
from a liquid.

2. The green matter of plants.
FEE'LEES. In conchology, those

crenated arms, evolved from the
side of the Lepas anatifera, and
other shells of the second division
of Lepas. While the animal is in
the water it continually moves its

feelers, evidently for the purpose
of entangling minute marine insects
as food. — Brown.

FE'LDSPAB. } A mineral which enters
FE'LSPAE. ) into the composition
and, next to quartz, constitutes
the chief material of many rocks.
There are many species and sub-
species, or varieties of this mineral,
though all agree nearly in their
chemical composition, and all are
found both crystallised and massive.
Feldspar is lamellar in its structure,
but not in so great a degree as
mica; it scratches glass, and is
nearly opaque. It is composed of
silex 64, alumina 18, potash. 13,
lime 3, and some oxide of iron.
Common feldspar is perhaps the
most generally diffused mineral,
next to quartz and iron. It is one
of the components of granite,
gneiss, and some other primary
rocks ; and granite owes its variety
of appearance and colour principally
to the abundance, or otherwise, of
the feldspar it contains. In some
kinds of granite the feldspar is in
large whitish crystals of irregular
forms, occasionally of one or two
inches in length. From the lia-
bility of feldspar to be decomposed
by atmospheric action, granite
containing large crystals of it is
less durable than that which is
finer grained, and it is said that
Waterloo-bridge, being unfortu-
nately built of granite containing
large crystals of feldspar, will be
less durable than could be wished
for. Felspar forms, in general,
more than half of the mass of
modern lavas. When it is in
great excess, lavas are called
trachytic; when augite (or py-
roxene) predominates, they are
termed basaltic.

Felspar assumes a considerable
variety of forms, which differ so
greatly from each other, that a
novice finds it difficult to recognise
in them the same substance. In

F E L

[ no]

F E L

an earthy, vitreous, or compact
state, it forms the basis of all lavas,
and of the quarter number of trap
rocks. Associated with augite,
and usually in a vitreous form, it
constitutes some of the well-known
modern volcanic basalts, in which
the greater or less preponderance of
the latter mineral confers the more
or less black, dense, and ferrugi-
nous character, which they often
assume. Mixed with hornblende,
it forms a large class of ancient
rocks, also called basalt when the
minerals are intimately blended,
or greenstone when each is dis-
tinguishable. In another condition,
felspar, in a glossy but loosely
aggregated state, composes a rock
of porous, rough, and earthy aspect,
called trachyte. In a compact
state, the same mineral is the base
of many of the porphyries ; and in
a more or less crystalline form,
associated with quartz, mica, and
other minerals, it composes the
great class of granite rocks. As
felspar is not found in any of the
aqueous sedimentary deposits, ex-
cept in a decomposed or regenerated
state, it may therefore be considered
the most characteristic ingredient
of all igneous rocks. Professor
Jameson divides felspar into five
species, namely, 1. Khombohedral
Feldspar, or Nepheline. 2. Pris-
matic Feldspar, or Common Feld-
spar. 3. Tetarto-prismatic Feld-
spar, or Scapolite. 4. Polychro-
matic or Labrador Feldspar. 5.
Pyramidal Feldspar, or Scapolite.
1. The rhombohedral feldspar,
or Nepheline of Haiiy and Werner,
is of a white or grey colour, and
occurs both massive and crystal-
lised; it is externally splendent,
internally vitreous and shining.
Cleavage fourfold. Fracture con-
choidal, melts with difficulty before
the blow-pipe. Its crystals form
druses. It occurs in drusy cavi-
ties. Its constituent parts are,

according to Gmelin, silica 43-46,
alumina 33*49, soda 13-36, potass
7'13. Other authors, however,
give a different analysis, stating
lime and oxide of iron to form a
portion of its constituents.

2. Prismatic feldspar, or common
feldspar. The prismatischer feld-
spath of Mohs. Potash feldspar.
Of this there are many varieties,
namely, adularia, or moonstone, a
transparent variety with a silvery
or pearly opalescence ; glassy feld-
spar, a translucent variety, with
various shades of colour, such as
white and red, which from its
abundance has obtained its name ;
amazon-stone, a blue or green
variety ; Norwegian Labrador feld-
spar, a dark-green variety with a
beautiful changeableness of colour,
obtained from Frederickswarn, in
Norway ; compact feldspar, a
feebly translucent variety, with a
splintery fracture; slaty feldspar,
or clinkstone, a slaty variety ; por-
celain earth, earthy feldspar, and
claystone, varieties, in a compara-
tively loose state of aggregation,
without lustre or transparency, and
varying in their degree of com-
pactness.

3. Tetarto-prismatic feldspar, or
albite. See AlUte.

4. Polychromatic or Labrador
feldspar. Lime feldspar. The
polychromatischer feldspath of
Mohs. This beautiful mineral
was first discovered on the coast of
Labrador, as a constituent part of
syenite. When light falls on it in
certain directions it exhibits the
most beautiful changeability of
colour. It occurs massive and
disseminated. Cleavage splendent.
Fracture glistening. It has been
subsequently found in different
parts of Europe. It contains about
eleven per cent, of lime and four
of soda. It breaks into rhom-
boidal fragments. In its change-
ability of colour, it exhibits patches

F E L

C

*• ] See Feldspar.

of blue, green, yellow, red, and
grey colour.

5. Pyramidal feldspar, or scapo-
lite. Meionite. Pyramidaler feld-
spath of Mohs. Of this species of
feldspar there are many varieties,
namely, Meionite, Scapolite, Par-
anthine, "Wernerite, Dipyre, and
Schmelzstein. These will be all
described under their several heads.
FE'LDSPARITE. | Names assigned by
FE'LSPAR ROCK, j Dr. Boase to a
genus of primary rocks found in
Cornwall. "All the varieties of
this genus, have, in common, a
basis of compact felspar, (i.e. a
compound of felspar and quartz)
which assumes various characters,
passing gradually from crystalline
felspar into hornstone, and even
into quartz, according as one or
other of its constituents predomi-
nates.

FE'LDSPATH.
FE'LSPATH.
FELSPA'THIC. ) Any mineral in which
FELSPA'THOSE. j feldspar greatly pre-
dominates ; of the nature of feld-
spar.

FE'LDSTEIN. \ The names assigned to
FE'LSTONE. ) a feldspathic granite
rock. A compact, smooth, hard
flinty looking rock. It is probably
a mixture of a feldspar with silica,
in a state of paste. It has two
principal varieties.

FE'LIS. (Lat.) A genus of quadru-
peds belonging to the order of
Ferse, the characters of which are
these : — The fore-teeth are equal ;
the molares, or grinders, have three
points; the tongue is furnished
with rough sharp prickles, pointing
backward ; the claws are sheathed
and retractile, and being raised
perpendicularly, and hidden be-
tween the toes when at rest, by
the action of an elastic ligament,
lose neither point nor edge. The
species of this genus are very
numerous, and various with regard

1 ] FEE

to size and colour, though they are
all similar with respect to form.

FE'MORAL, (femoralis, Lat.) Belong-
ing to the thigh.

FE'MUR. (Lat.) The thigh bone;
the thigh.

FENESTE'LLA. The name given by-
Hugh Miller to a genus of fossil
corals of the Dudley rocks and
mountain limestone. The fenes-
tella is a stony coral, fixed at the
base, and composed of branches,
which unite by growth and form a
cup. " Externally the branches
anastomose, or regularly bifurcate ;
internally they form a net-work,
the intervals being generally oval.
One row of pores on each of the
branches externally, the openings
being circular, and projecting
when perfect." Mr. Lonsdale has
distinguished four species, namely,
F. antiqua ; F. Milleri ; F. prisca ;
and F. reticulata, all of which are
figured and described in Sir E.
Murchison's splendid work, the
Silurian System.

FE'RGTTSONITE. A brownish-black ore,
occurring in quartz ; thus named
after Mr. Ferguson of Eaith.

FERN. (Sax. fearn.} Ferns are dis-
tinguishable from all other vegeta-
bles by the peculiar division and
distribution of the veins of the
leaves ; and in arborescent species
by their cylindrical stems without
branches, and by the regular dis-
position and shape of the scars
left upon the stem, at the point
from which the petioles, or leaf-
stalks, have fallen off. The brake,
or fern, of our commons and waste
lands, is a familiar example of this
remarkable and numerous family
of plants, distinguished by the
peculiar distribution of the seed-
vessels. The family of ferns, both
in the living and fossil flora, is the
most numerous of vascular crypto-
gamous plants. The total number
of living species of ferns is about
1500. The large tree ferns are

F E It

[172]

FIB

confined almost exclusively to the
tropics; an elevated and uniform
temperature and great humidity
being the conditions most favour-
able to their development. The
existence of immense fossil arbo-
rescent ferns, from thirty to forty
feet in height, in the coal formation,
is one of the strongest possible evi-
dences of the great diminution of
temperature and change of climate
which the earth has undergone. In
the coal formation there are not
fewer than 130 known species of
ferns, nearly all of which belong to
the tribe of Polypodiaceae. An
arborescent fern, forty - five feet
high, from Silhet in Bengal, may
be seen in the stair-case of the Bri-
tish Museum. In the strata of the
secondary series there is a consider-
able diminution in the absolute
and relative number of ferns ; and
in the strata of the tertiary series
the ferns seem to bear nearly the
same proportion to other vegetables
as in the temperate regions of the
earth at the present day.— Auck-
land. I/yell. Mantell.

FER'RUGINOUS QUARTZ. (Called also
Iron-flint.) The Eisenkeisel of
Werner; Quartz Bubigineux of
Haiiy. A subspecies of quartz,
opaque, or translucent at the edges
only. Fracture uneven, more or
less conchoidal, but imperfect, shi-
ning, and nearly vitreous. It
occurs massive and crystallized.
Some authors divide ferruginous
quartz into yellow and green
varieties. Cleaveland mentions
two varieties, yellow and red.
Ferruginous quartz consists of sil-
ica 93, oxide of iron 5, oxide of
manganese 1.

FE'TID LIMESTONE. The Stinkstein of
the Germans. A limestone which,
when struck with the hammer,
gives off a fetid smell, like that of
sulphuretted hydrogen gas.

FETUS. (fatus, Lat.) Commonly
written fatus. Of viviparous ani-
mals, the young in utero ; of ovi-

parous, the young in the shell : in
the earliest stages of utero-gestation,
the young is usually called the
embryo, and when fully formed, or
after a certain period, the fetus.

FI'BER. ] (fibra, Lat. fibre, Fr. fibra,

FI'BRE. ) It.) A filament or thread,
whether of animal, vegetable, or
mineral structure.

FI'BRIL. (fibrille, Fr. petite fibre,
fibritta, It.) A small fibre; the
diminutive of fibre.

FI'BROUS. ffibreaux, Fr. fibroso, It.)
Composed of fibres ; containing
fibres.

In botany, a fibrous root consists
of numerous fibres, either simple
or branched; these are the most
simple of all roots, conveying nou-
rishment directly to the stem, or
leaves.

FIBROUS QUARTZ. See Cat's Eye.

FI'BROLITE. (from fibra, Lat. and
\lOo<s, Gr.) A mineral of a white
or grey colour, occurring with
corundum. Cleavage imperfect.
Hardness more considerable than
that of quartz. Consists of alumina
46, silica 33, oxide of iron 13. It
is composed of minute fibres, from
which circumstance it obtains its
name, some of which appear to be
rhomboidal prisms. It is found in
China and in the Carnatic.

FI'BULA. (Lat.)

1. The small bone of the leg, thus
named, according to some authors,
from being placed opposite to the
part where the knee-buckle, or
clasp, was formerly used.

2. A fossil echinite, resembling,
not a buckle, but a button. By
some oryctologists these have been
termed Bufonitse and Scolopendritae,
and by others Pilei; and, by the
English, Capstones. — Parkinson.

FIBULA'RIA. A genus of echinites,
subglobular, ovoid and nearly round,
with no determinate margin; the
ambulacra forming petaloidal, short,
narrow, and circumscribed figures,
the mouth beneath, central; the

FIG

[173]

PIE

vent near to the mouth. Many
species have been described.

FI'GTTRE STONE. Agalmatolite, a va-
riety of talc-mica, of a grey, green,
white, red, or brown colour. The
finest are brought from China.

FI'LAMENT. ffilamenta, Lat. filament,
"Fi.filamtnto, It.

1. A long thread or fibre; a slender
thread-like process.

2. In botany, the long thread-like
part that supports the anther ; the
filament is not essential, being
sometimes wanting; the form is
various, being sometimes short and
thick, or long and slender, or
forked, one point only supporting
the anther ; generally smooth,
sometimes hairy ; the number
varies from one to many. Most
filaments are simple, some are
bifid ; others tricuspidate or broad,
and trifid at the extremity.

FILAMENTOUS, (filamenteux, Fr.fila-
mentoso. It.) Composed of fine
threads or fibres.

FILA'BIA. A genus of nematoidea,
belonging to the class Entozoa.

FILE. A name given by the chalk-
diggers to the striated and prolonged
cucurmerine claviculae of echinites.

FILI'CES. (filix, Lat.) Ferns, the first
order of Cryptogamia, in Linna3us's
artificial system ; the first tribe of
acotyledonous plants. In modern
classification, filices constitute the
fourth order of Acrogens.

FILICITE. A fossil fern.

FILICOIDE'.E. (from Mix, Lat. and
eiSos, Gr.) Fern-like plants.

FI'LIFORM. (from filum, a thread,
and forma, form, Lat.) Thread-
like; thread- shaped; slender, and
of equal thickness. In botany, ap-
plied to peduncles when very fine,
resembling threads; applied also
to the tube of monopetalous flowers
when of a thread-like form; and
also to aments.

FIN. (Sax.) The organ in fishes by
which they steady and keep upright
their bodies in the water; the cau-

dal fin alone assists in progressive
motion. The fin consists of a
membrane supported by rays, or
little bony or cartilaginous ossicles.

FIN-FOOTED. Palmipedous ; having
palmated feet, or feet with mem-
branes between the toes, connecting
them with each other.

FI'ORITE. A siliceous incrustation
deposited by the thermal waters of
Ischia, first noticed by Dr. Thomp-
son ; called also Pearl-sinter. By
some mineralogists, this is con-
sidered to be merely a variety of
siliceous sinter; others constitute
it a distinct sub-species. It occurs
in stalactitical, botryoidal, globular,
and cylindrical masses of a milk-
white, yellowish -white, pearl-grey,
and yellowish-grey colours. It is
less hard than quartz, but suffi-
ciently hard to scratch glass. It
is infusible before the blow-pipe,
without addition. It consists of
silica 96, or, according to some,
94, alumina 2, lime 4. It is re-
garded by some authors as a vol-
canic product.

FIRE-DAMP. Choke-damp. Carbu-
retted hydrogen gas. This is some-
times very abundantly evolved in
coal mines, and is productive of the
most dreadful results, occasionally
nearly all employed in the mines
perishing from its combustion.
When carburetted hydrogen gas
constitutes more than one-thir-
teenth of the volume of the atmos-
phere of pits and mines, the whole
become explosive whenever a flame
is brought into contact with it ; to
prevent the disastrous consequences
which were so frequently resulting,
Sir H. Davy invented a safety-lamp,
which being formed of wire-gauze,
in the form of a cylinder, consumes,
but does not explode, the explosive
mixture. It has been well and
truly observed, "if the genius of
Davy had merely produced his
safety-lamp, it would alone have
entitled him to the applause and

FIR

[174]

F I S

thanks of mankind." Fire-datnp,
or carburetted hydrogen gas, ap-
pears to be generated by the de-
composition of iron pyrites in coal,
and may often be heard issuing
from the fissures in coal-beds with
a bubbling noise, as it forces the
water out with it. In Messrs.
Coriybeare and Phillips' Geology of
England and Wales, it is stated
that the pit-men occasionally open
with their picks, crevices in the
coal or shale, which emit 700
hogsheads of fire-damp in a minute.
These blowers, as they are termed,
continue in a state of activity for
many months together. The after-
damp, or stythe, which follows the
explosions, is a mixture of the car-
bonic acid and azotic gases, re-
sulting from the combustion of the
carburetted hydrogen in atmos-
pheric air, and more lives are de-
stroyed by this than by the violence
of the fire-damp explosions. Sir
H. De La Beche observes, "it
appears very remarkable that in
the coal districts of the British
Isles, where such a large amount
of carburetted hydrogen is annually
produced, means have not been
adopted for making an economical
use of this gas, both as repects
light and heat."

TIRE OPAL. Called also Girasole. The
Feur Opal of Klaproth; Quartz
Besinite Girasol of Haiiy. A sub-
species or variety of opal, according
to some authors, of a hyacinth-red
colour, but according to others pre-
senting bright hyacinth- red and
yellow colours, when turned to wards
the light. It has been hitherto
obtained chiefly from Mexico and
the Faroe Islands. See Girasole
and Opal.

FIRE-STONE. (The craie chloritee, ou
glauconie crayeuse, of the French
geologists.) Known also as the
Merstham beds ; and Upper Green
sand. From the application of the
stone found in some parts of this

deposit in the construction of fur-
naces, ovens, &c., it has obtained
the name of fire-stone. An aren-
aceo-argillaceous deposit of a grey-
ish green colour, composed of marl
and grains of silicate of iron ; in
some places, in a state of sand ; in
others, forming a stone sufficiently
hard for building. The transition
from the marl to the fire-stone is in
many localities so gradual, and the
sandy particles are so sparingly
distributed, that the chalk-marl
may be said to repose immediately
on the gait; in others, however,
the characters of the fire-stone are
very peculiar, and some geologists
have deemed them of sufficient
importance to rank this deposit as
an independent formation. The
fire-stone contains the same fossils
as the grey-marl, and a few species
not found in any other bed. — Dr.
Mantell.

FI'SSILE. ffissilis, Lat.) Capable of
being split, or divided, in the
direction of the grain or cleavage.

FISSIRO'STRES. A family of birds, nu-
merically small, but very distinct
from all others in the beak, which
is short, broad, horizontally flatten-
ed, slightly hooked, unemarginate,
and with an extended commissure,
so that the opening of the mouth
is very large, which enables them
to swallow with ease the insects
they capture while on the wing:
the swallow belongs to this family,
and is an example.

FISSURE'LLA. A gasteropod ; a genus
of the order Scutibrancbiata. A
buckler-formed univalve, without
spire : the vertex perforated by a
small ovate or oblong orifice, which
affords a passage to the water re-
quired for respiration ; this orifice
penetrates into the cavity of the
branchiae, which are situated on
the fore part of the back. The
fissurella has been found in the
Essex cliffs.

FISTULA'.N A. A genus of the family

F I S

[ 175]

F L I

Inclusa, class Acephala, division
Mollusca. Nearly all of the family
Inclusa live buried in sand, stones,
ooze, or wood. The external tube
of fistulana is entirely closed at its
larger end, and is more or less like
a bottle or club. The fistulanae
are sometimes found buried in sub-
merged fragments of wood, or in
fruits, and the animal like the
teredo, has two small valves, and
as many palettes. Recent speci-
mens are only obtained from the
Indian ocean, but flstulance are
found fossil in the Shanklin sand,
where, in some instances, the wood
is studded with the remains of a
small species of fistulana, of a pyri-
form shape, about one-third of an
inch long, to which the name of
Fistulana pyriformis has been given.
Fistulanae personate are found in
the chalk formation, and in the
arenaceous limestone, or sandstone,
of Bognor ; and Fistulana pyri-
formis, at the junction of the Gait
and Shanklin sand, imbedded in
wood.

FI'STTTLIFOEM. (horn fistula and forma,
Lat.) In round hollow columns.

FI'STTJLOTJS. (fistuleux, Fr. infatoUto,
It.) Hollow; tube-like.

FI'XITY. (fixite, Fr. propriete qu'ont
quefyues corps de n'etre point dissipes
par V action du feu.) Coherence of
parts: that property which some
bodies possess of resisting dissipa-
tion by heat.

FLAGSTONE. "When sandstones are
very thin-bedded, or the beds are
easily split along the lines of lami-
nation, they are called flagstones.
Flagstones are not exclusively
areaaceous, but may be argilla-
ceous, or even calcareous. — Jukes.

FLAMMI'VOMOUS. (from flamma and
vomo, Lat.) That vomits forth
flames; volcanoes areflammivomous.

FLE'XIBLE. (flexibilis, Lat. flexibile,
Fr. flessilile, It.) That can be
bent; not brittle; pliable. That
substance is said to be flexible

which, being bent, does not itself
resume its former shape ; but con-
tinues in the form forcibly given
to it. Substances which, being
bent forcibly, spring back to their
former position, are termed elastic.
FLINT. (Sax.) Siliceous earth, nearly
pure. Flint is the commonest form
in which quartz exhibits itself; it
is rather harder than quartz, and
contains a minute portion of alu-
mine, lime, and oxide of iron ; 98
per cent, being pure silex. A
remarkable circumstance attending
flint is, that it is found in masses,
dispersed in regular parallel beds,
in chalk-rocks. This is elucidated,
and partly explained, in a beautiful
manner in the manufacturing of
porcelain. Porcelain is made of
flint and clay, pounded extremely
fine, and mingled together with
water so perfectly, as to form a
smooth fluid, of the consistence and
colour of cream; if this fluid be
left a long time tranquil, the flint
separates from the clay, and collects
in small masses, in a manner anala-
gous to that in which the natural
masses occur in the chalk. "When
flint is first extracted from the
quarry it is much more brittle,
and requires a much lighter blow
to break it, than flint that has been
long exposed. This may perhaps
be owing to the moisture or water
belonging to the flint in its natural
state, but which it loses in great
measure by the joint action of the
sun and air. It has a conchoidal
fracture, and feeble lustre; thin
fragments are translucent. Specific
gravity 2-594. According to Klap-
roth's analysis, it consists of silex
98, lime 0-5, alumine 0-25, oxide
of iron 0-25, water 1. Before the
blow-pipe, flint per se is infusible,
but it whitens and becoms opaque.
"When two pieces of flint are rubbed
together, they emit a peculiar smell,
and phosphorise greatly. The con-
stant occurence of flint in the upper

L I

[176]

F L I

chalk, and the apparent conversion
of animal remains into flint, has
given rise to much speculation
respecting its origin; and it was
at one time maintained, that flint
and chalk were convertible, or
capable of undergoing a mutual
transmutation. One thing appears
very certain, that the veins of flint
so freely distributed throughout
the chalk, are invariably confined
to that formation. I propose to
submit a few observations from the
pens of our first writers on this
interesting and intricate subject,
for after having considered the
matter in every point of view ;
after having carefully read the
opinions of others, and again and
again examined strata of flint
nodules and tabular flints, flints
horizontally and diagonally distri-
buted throughout the numerous
chalks pits in my neighbourhood ;
after having observed their crushed
but not disordered condition, and
having commonly found flints im-
bedded in flints, I am totally
unable to arrive at anything ap-
proaching to a legitimate deduction
from the various phenomena.

"That the beds of chalk and
flint were deposited periodically,"
says Dr. Mantell, "cannot admit
of the slightest doubt. Specimens
are not unusual, in which angular
fragments of black flint, that could
not possibly have been originally
formed in "their present state, are
imbedded in chalk. Sir Henry
Englefield was the first who di-
rected the attention of geologists
to the subject of the shattered
condition of the flints found in
certain strata. In a paper read
before the Linnsean Society, he
notices several beds of shattered
flints, which occur in a chalk-pit
at Carisbrook, in the Isle of "Wight ;
and, after describing their situation
and appearance, proceeds to offer
some conjectures upon the probable

cause of their destruction. This he
supposed might have been occa-
sioned by some sudden shock or
convulsion, which in an instant
shivered the flints, though their
resistance stopped the incipient
motion ; for the flints, though
crushed, are not displaced, which
must have been the case, had the
beds slid sensibly. Chalcedony
is often found occupying the hol-
lows of flints, and on this sub-
ject it has been remarked that
although in the present com-
pact state of the matter of flint,
it is not easy, though possible,
to force a fluid slowly through its
pores, yet it is probable that
before its consolidation was com-
plete, it was permeable to a fluid
whose particles were finer than its
own; and that the particles of
chalcedony, whilst yet in a fluid
state, being finer than those of
common flint, did thus pass through
the outer crust to the inner
station they now occupy; where
they also allowed a passage through
their own interstices to the still
purer siliceous matter, which is
often crystallized, in the form of
quartz, in the centre of the chalce-
dony, and is so entirely surrounded
by it, that it could have no access
to its present place, except through
the substance of the chalcedony,
and the flint enclosing it." In
Professor Buckland's Bridgewater
Treatise we find the following :
" We may in like manner refer
the origin of those large quantities
of silex, which constitute the chert
and flint beds of stratified forma-
tions, to the waters of hot springs,
holding siliceous earth in solution,
and depositing it on exposure to
reduced degrees of temperature and
pressure, as silex is deposited by
the hot waters that issue from the
geysers of Iceland." Again Dr.
Mantell, "the nodular masses of
flint are very irregular in form,

F L I

[177]

F L I

and variable in magnitude ; some
of them scarcely exceeding the
size of a bullet, while others are
several feet in circumference. Al-
though thickly distributed in hori-
zontal beds and layers, they are
never in contact with each other,
but every nodule is completely
surrounded by chalk. Flints so
commonly enclose the remains of
sponges, alcyonia, and other zoo-
phytes, that some geologists are of
opinion that the nucleus of every
nodule was originally an organic
body, and Townsend states, ' so far
as my observation goes, zoophytes
appear universally to have formed
the nuclei of nodulated and coated
flints. The nodules of flint fre-
quently exhibit the internal struc-
ture of the enclosed zoophyte most
beautifully and delicately preser-
ved.'* A theory offered by Profes-
sor Buckland is to this effect : "It
does not appear possible that flints
could have been formed by infil-
tration into pre-existing cavities,
like the regularly disseminated
geodes of the trap rocks. Assuming
that the mass which is now sepa-
rated into beds of chalk and flint,
was, previously to its consolidation,
a compound pulpy fluid, and that
the organic bodies now enveloped
in the strata were lodged in the
matter of the rock, before the
separation of its calcareous from
its siliceous ingredients, the bodies
thus dispersed throughout the
mass would afford nuclei, to which
the flint, in separating from the
chalk, would, upon the principle
of chemical affinity, have a ten-
dency to attach itself. The chalk
and flint proceeded through a
contemporaneous process of con-
solidation; the separation of the
siliceous from the calcareous in-
gredients being modified by
attractions, which drew to certain
centres the particles of the siliceous
nodules, as they were in the act of

separation from the original com-
pound mass. The distances of the
siliceous strata must have been
regulated by the intervals of pre-
cipitation of the matter from which
they are derived ; each new mass,
as it was discharged, forming a
bed of pulpy fluid at the bottom of
their existing ocean, which being
more recent than the bed produced
by the last preceding precipitate,
would rest upon it as a foundation
similar in substance to itself, but
of which the consolidation was
sufficiently advanced to prevent the
ingredients of the last deposit, from
penetrating or disturbing the pro-
ductions of that which preceded it."
The present shape of many chalk
flints being that of organic bodies,
demonstrates the latter to have
existed before the consolidation of
the former; for the fidelity with
which the site has often copied the
organization, and even the accidents
and irregularities of the bodies
enveloped is so accurate, that it is
impossible to attribute the form of
the flint to any other cause than
that of the body on which it was
deposited. Sometimes the organi-
zation is so delicately retained that
it seems not to have undergone the
smallest derangement before the
siliceous cast was taken, and the
model is thus permanently preser-
ved. The organic bodies that
afforded nuclei to these nascent
flints, appear to have been dispersed
pretty uniformly through the origi-
nal compound mass, which is now
divided into beds of chalk and
flints, but it is not easy to deter-
mine what cause it was that regu-
lated the distances at which the
beds of flint have been disposed, or
to say why we sometimes find
organic bodies preserved in flint,
at other times enveloped and filled
only by pure chalk. In many
silicified spunges and alcyonia, the
outer crust being composed of flint

F L I

[ 178 ]

FLU

in its common state, represents
rudely the outline of the body
inclosed. But the internal struc*
ture retains traces of all its tubes
and fibres, most delicately preserved
in a reddish caldedony. Sir H.
Davy found pure flint in the cuticle
of many grasses ; it is also found in
the hollow stems of bamboo ; the
ashes of wheat straw are also found
to contain it.

FLI'NTY SLATE. Flinty slate differs
from common slate, in containing
a large portion of siliceous earth.
Slate and flinty slate not only pass
into each other, but frequently
alternate. When flinty slate ceases
to have the slaty structure, it
becomes hornstone, or, what the
French geologists term petrosilex.
If it contains crystals of felspar,
it becomes hornstone porphyry. —
JBakewett.

FLO'ATSTONE. The white and grey
porous varieties of rhombohedral
quartz. In consequence of their
extreme pourousness they swim on
the surface of water, and have
therefrom been named floatstone,
or spongiform quartz.

FLOETZ. (flotz, Germ.) The name
given by Werner to certain rocks
which were flat, horizontal, and
parallel to each other. Werner
employed this term, in lieu of
secondary, for the rocks reposing
on his transition series, from the
belief that they generally were
stratified in planes nearly horizon-
tal, while those of the older strata
were inclined to the horizon in
considerable angles. This however,
holds good only as regards the
structure of countries comparatively
low ; in mountain ranges Werner's
floetz formations are highly incli-
ned. As therefore vertical floetz
formations imply a manifest con-
tradiction of terms, the use of the
word floetz in the place of secon-
dary is inadmissable.

FLO'BA. (Lat.) As the animals

peculiar to any country constitute
its fauna, so do the trees and plants
itsj#ora; the botany of a country.

FLO'EAL. (floralis, Lat.) An epi-
thet for a bud or leaf; pertaining
to flowers; belonging to the
flower. The calyx is the outer set
of i\iQ floral envelopes.

FLO'BET. (fleurette, petite fleur, Fr.)
A floret is a small monopetalous
flower, many of which, enclosed in
one calyx or perianthium, and
placed sessile on a common un-
divided receptacle, form a species
of compound flower.

FLU' ATE. A compound of fluoric acid
with a salifiable base.

FLTJ'CAN. A provincial name for a
fault or dam ; particularly used by
the Cornish miners. 2. A term
applied by the Cornish miners to
either a white or a greenish clay,
without regard to its composition.

FLTJ'OE. ] (Lat.) Octahedral

FLTJ'OE SPAE. ) fluor. Octaedris-
cbes Flus-Haloide of Mohs. Chaux
Fluate of Haiiy. Fluate of lime ;
consisting of 67*75 lime and 32-25
fluoric acid. If a cube of fluor
spar be split with a knife and a
hammer, it will yield only in the
direction of the solid angles, and
if the division be pursued the
result will be an octohedron. There
are three varieties of fluor spar;
the first, with even fracture and
feeble lustre, is called compact
fluor; the second, in which the
cleavage is distinct, foliated fluor ;
the third, which occurs incrusting
other minerals, earthy fluor. See
also Blue-John and Derbyshire spar.

FLUOE'IC ACID, i An acid first pro-

FLUO'EINE. ] cured by Gay
Lussac, or by Margraff, and called
fluorine by Sir H. Davy. It may
be obtained by putting a quantity
of fluor-spar in powder into a
leaden retort, pouring over it an
equal quantity of sulphuric acid,
and then applying a very gentle
heat. From its exceedingly de-

FLU

[ 179]

F OL

structive properties it has been
called phtore, from (fredpio?, Gr.,
by M. Ampere. It destroys the
skin, almost immediately, if applied
to it, producing very painful
wounds. The most singular pro-
perty which it possesses is that of
corroding glass and siliceous bodies,
especially when hot, and the thick-
est glass vessel can only withstand
its action for a short time.

Fluorine enters into the compo-
sition of some minerals which form
constituent portions of great masses
of rocks. Fluoric acid is found in
mica and hornblende, two minerals
of very great importance, as com-
ponent parts of many rocks.
Fifteen analyses of mica, from
various parts of the world, by
Klaproth, Vauquelin, Kose, and
Bendant, afford as a mean, 1*09
per cent, of fluoric acid; and
Bousdorf s analysis of hornblende,
gives 1.5 per cent, of the same
substance. Calculation affords us
0*36 of fluoric acid in gneiss with
mica, 0'54 in mica slate, 0*75 per
cent, in hornblende rock and green-
stone, 0'18 in granite with mica,
0'5 of the same substance in
sienite, 0*5 per cent, in porphy-
ritic greenstone. Fluor spar is,
however, the mineral in which the
greatest relative amount of fluorine
is detected. — De la Beche. The
symbol of fluorine is F.
FLI/STRA. A genus of polyparia,
class Vermes, order Zoophyta. If
we carefully observe the patches of
white calcareous matter, called
flustrse, that may be seen on every
sea-weed or shell on the shore,
appearing like delicate lace, we
shall discover that these apparently
mere specks of earthy substance
belong to the animal kingdom.
The flustra, when taken fresh and
alive out of the water, presents to
the naked eye the appearance of
fine network, coated over with a
glossy varnish. "With a glass of

moderate powers, it is discovered
to be full of pores, disposed with
much regularity. If a powerful
lens be employed, while the flustra
is immersed in sea- water, very
different phenomena appear; the
surface is seen to be invested with
a fleshy, or gelatinous, substance,
and every pore to be the opening
of a cell or cavity, whence issues
a tube with several long feelers or
tentacula ; these expand, then sud-
denly close, withdraw into the cells,
and again issue forth; and the whole
surface of the fiustra is studded with
these hydra-like forms, sporting
about in all the energy and activity
of life. For a more full account,
see Dr. Mantell's Wonders of Geo-
logy, whence the above is taken.
FLUX, (jluxus, Lat. flux, Fr. mouve-
ment regU de la mer vers U rwage d
certaines heures dujour.J

1. The flow of the tidal wave : the
flux is the rise; the reflux, the
ebb of the tide.

2. Any substance added to facilitate
the fusion of metals or minerals.

F(E'CAL, See Fecal.
FCE'CES. See Feces.
FO'LIATED. (foliatus, Lat.)

1. In botany, leaved or having
leaves.

2. In conchology, in laminae or
] eaves, as when the edges of the
shelly layers are not compact, but
seem to separate from each other.
This may easily be seen in the large
coarse oyster shell.

3. In mineralogy, the term foliated
was used by Werner to express
the structure of such minerals as
may be divided or cleaved regularly,
and were therefore said by him to
consist of folia or leaves.

FOLIA'TION.

1. In botany, vernation or leafing
of trees, &c.

2. In mineralogy, the act of beating
into thin leaves.

3. Mr. Darwin proposes to give the
term foliation to the tendency in

F 0 L

L 180]

FOR

certain rocks to split, foliate^ or
cleave in a certain given direction ;
by foliation is meant, a separation
into layers of different chemical
composition, while cleavage means
only a tendency to split, in a mass
of the same composition.

FO'LKSTONE MAEL. A stiff marl,
varying in colour from a light
grey to a dark blue, more gene-
rally known under the provincial
term Gait. The thickness of this
bed is in some places, in the South
of Sussex, not less than between
two and three hundred feet. It is
a member of the cretaceous group,
lying between the upper and lower
green-sand. Where the Folkstone
marl is exposed, and forms the
surface of the country, the soil is
exceedingly tenacious, and ranks
amongst the finest and most pro-
ductive. The Folkstome marl
abounds in fossils.

FO'LLICLE. (folliculus, Lat. follicule,
Fr.follicoh, It.)

1. In botany, a univalvular peri-
carp, opening on one side longitu-
dinally, and having the seeds loose
in it ; a membranous seed-vessel of
one valve and one cell, bursting
lengthwise, and having no apparent
suture to which the seeds are
attached.

2. In anatomy, a small secreting
cavity.

FONTANE'L. (fontanelle, T?r.fontanella,
It.) An opening left in the skull
at birth, which is subsequently
closed by osseous deposit; there
are two fontanels.

FORA'MEN. (Lat.) A hole ; an
opening ; generally, by which
nerves or blood vessels obtain a
passage through bones. In botany,
the opening in the ovulum. When
the foramen is visible on the seed,
as is the case in the bean and pea,
it is called the micropyU.

FOBA'MINATED. } (from for ammo, Lat.)

FORA'MINOTJS. ) Pierced with small

openings; full of small holes;
porous.

FOBAMINI'FEEA. The second order of
the class Astomata, comprising
Rotalia, Nodosaria, Nummulites,
and Orbitolites. This order has
been constituted a class by Pictet
and D'Orbigny, and divided into
seven families.

FOEAMINI'FEEOUS. Belonging to the
order foraminifera.

FO'ECIPATED. (forcipatm, Lat.) Hook-
ed, or furnished with pincers, as
the claws of a lobster, crab, &c.

FOBMA'TION. (formatio, Lat. forma-
tion, Fr. formazione, It.) Any
assemblage of rocks possessing some
character in common, either as
regards their age, origin, or compo-
sition. When a series of strata
of a similar rock are arranged with
occasional strata intervening, of
rocks of another kind, which recur
in different parts of the series, they
are regarded as having been all
formed nearly at the same epoch,
and under similar circumstances;
and such series are called by
geologists formations. Thus, the
strata of shale, sand-stone, and
iron-stone, that accompany beds of
coal, are called the coal formation.
Strata of different kinds, in which
a gradation is observed into each
other, and which contain similar
species of organic remains, con-
stitute a geological formation. The
chalk with flints above, the lower
chalk without flints, the chalk-
marl, and the green-sand under the
chalk, are all regarded as members
of the chalk formation. — Bakewell.

FO'ENICATED. (fornicatus, Lat.) Con-
cave within, and convex without ;
vaulted; arched.

FO'BNIX. (Lat.) In conchology, the
excavated part under the umbo. It
likewise signifies the upper, or con-
vex shell in the ostrea.

FORTIFICATION AGATE. The name
given to a variety of agate which,
when cut and polished, presents

F 0 S

[ 181 ]

FRO

lines running in such directions as
to resemble a fortification, the
centre being often amethyst, with
jasper, quartz, &c., surrounding.
In composition it resembles other
agates ; it occurs in irregular nod-
ules, commonly in amygdaloid, as
in that of Scotland, called Scotch
pebble.

FO'SSIL. | ffossiliSj from fodio, Lat.

FO'SSILE. ) fossile, Fr. fossile, It.)
Dug out of the earth, as fossil
shells, fossil bones, fossil coal, &c.
The adjective is frequently spelt
fossile.

FO'SSIL. A substance dug out of the
earth. At the present day, the
word fossil is used by geologists to
express only the remains of animal,
or vegetable, substances found buried
in the earth's crust.

Fossil shells of forms such as
now abound in the sea, are met
with far inland, both near the sur-
face and at all depths below it, as
far as the miner can penetrate.
They occur at all heights above
the level of the ocean, having been
observed at an elevation of from
8,000 to 9,000 feet in the Alps and
Pyrenees, more than 13,000 feet
in the Andes, and above 15,000
feet in the Himalayas. — Lyell.

Mr. W. Smith was the first to
notice that certain fossils are pecu-
liar to, and are only found lodged
in, particular strata. The rapid ad-
vances made in geology have taught
the following facts respecting
fossils : that exactly similar fossils
are found in distant parts of the
same stratum, not only where it
traverses this island, but where it
appears again on the opposite coast;
that in strata of considerable com-
parative depth, fossils are found,
which are not discovered in any of
the superincumbent beds: that
some fossils, which abound in the
lower, are found in diminishing
numbers through several of the
superincumbent, and are entirely

wanting in the uppermost strata :
that some fossils, occurring in con-
siderable numbers in one stratum,
become very rare in the adjacent
portion of the next superincumbent
stratum, and afterwards are lost:
that most of the remains which are
abundant in the superior strata, are
not at all found in the lower. —
Geological Transactions.

FRA'GMENTABY. Composed of frag-
ments. Dr. Johnson says, "a word
not elegant, nor in use : " in ele-
gance or euphony it may, or may
not, be deficient, but, at the
present day, it is in use by
geologists.

FKANGIBI'LITY. (In mineralogy, one
of the physical characters of miner-
als.) Capability of being broken.
The degree of frangibility consists
in the ease with which a thing may
be broken. This quality varies
greatly in different substances,
ranging through all the interme-
diate degrees, from very brittle to
very tough. FrangibiUty, strictly
speaking, ought not to be considered
as connected with the ease or diffi-
culty with which minerals yield in
directions parallel to their natural
joints; it is rather applicable to
their property of yielding to me-
chanical force in other directions.

FBEE-STONE. Any kind of stone, the
texture of which is so free or loose
that it may be easily worked.

FB'ESHET. A flood or overflowing of
a river, by means of heavy rains or
melted snow ; an inundation of
fresh-water. Freshets take place,
more or less, in all rivers, greatly
augmenting their velocities and
transporting power, and carrying
forward substances that could not
have been moved under ordinary
circumstances..

FEOND. (from, Lat.)

1. In botany, implies peculiar
union of the fructification with the
leaf and stem, namely, the flowerg

FRO

and fruit are produced from the
leaf itself.

2. The herbaceous parts of flower-
less plants, resembling leaves, are
called fronds ; they differ from true
leaves in their structure in many
respects.

FBONT. (front, Fr. fronte, It.) In
eonchology, when the aperture in
univalves is turned towards the
observer.

FBO'NTAL. ffrontale, Lat. frontal, Fr.
frontale, It.) Appertaining to the
forehead.

FBTJCTIFICA'TION. (fructification, Fr.
fruttificazidne, It.)

1 . The temporary part of a vegeta-
ble appropriated for generation,
terminating the old vegetable, and
beginning the new. It consists of
the following parts; namely, the
calyx, corolla, stamen, pistillum,
pericarpium, semen, and recepta-
culum.

2. The act of bearing fruit; fer-
tility; fecundation.

F'FCHSITE. A variety of mica con-
taining chrome.

FU'COID. (from 0<kos and eidos, Gr.)
A species of fucus. Fucoids are
very abundant in many of the
strata, occurring in the transition
strata of North America in nume-
rous thin layers. An account of
these has been published by Dr.
Harlan, of America, and by Mr.
B. C. Taylor, in London's Magazine
of Natural History. Fucoids are
found in great abundance in the
granwacke slate of the Maritime
Alps, in the lias, and in the chalk.
There is one species, the Fucoides
targionii, that abounds in the
upper green- sand. To a fine
species, discovered in the chalk by
Dr. Mantell, he has given the
name Fucoides Brongniarti.

Fu'cvs. (fucus, Lat. 0t)/co?, Gr.)
A genus of the order of Algae,
belonging to the class Cryptogamia.
This genus comprehends most of

[ 182 ] FUR

those plants commonly called
weed : pi ; fuci.

cfLQOBiTE. (/ulguritm, Lat.) Any-
thing struck by lightning. Rocks,
and the tops of mountains, often
bear the marks of fusion from the
action of lightning ; and occasion-
ally vitreous tubes, descending
many feet into banks of sand,
mark the path of the electric fluid.
Some years ago, Dr. Fiedler exhi-
bited several of the fulgorites in
London, which had been dug out
of the sandy plains of Silesia and
Eastern Prussia. — Mrs. Somerville.
" In a broad land of sand-hil-
locks," says Mr. Darwin, "which
separate the Laguna del Potrero
from the shores of the Plata, at the
distance of a few miles from Mal-
donado, I found a group of those
vitrified, siliceous tubes, which are
generally supposed to have been
formed by lightning entering the
loose sand. These tubes resemble
in every particular those from
Drigg in Cumberland, described in
the second vol. of the Geological
Transactions. The internal surface
is completely vitrified, glossy, and
smooth. A small fragment ex-
amined under the microscope, ap-
peared, from the number of minute
entangled air, or, perhaps, steam
bubbles, like an assay fused before
the blow-pipe. The sand is en-
tirely, or in greater part, siliceous ;
but some points are of a black
colour, and from their glossy sur-
face possess a metallic lustre. The
thickness of the wall of the tube
varies from a thirtieth to a twenti-
eth part of an inch, and occasionally
even equals a tenth. On the out-
side, the grains of sand are rounded,
and have a slightly glazed appear-
ance : the tubes are generally com-
pressed, and have deep longitudinal
furrows, so as closely to resemble a
shrivelled vegetable stalk, or the
bark of the elm or cork tree. Their
circumference is about two incheB;

F U L

[ 183]

F U S

but in some fragments which are
cylindrical and without any fur-
rows, it is double, or four inches.
The compression from the sur-
rounding loose sand, acting while
the tube was still softened from
the effects of the intense heat, has
evidently caused the creases or
furrows. Judging from the un-
compressed fragments, the measure
or bore of the lightning must have
been about one inch and a quarter.
At Paris, M. M. Hachette and
Beaudant succeeded in making
tubes, in most respect similar to
these fulgorites, by passing very
strong shocks of galvanism through
finely powdered glass: when salt
was added, so as to increase its
fusibility, the tubes were larger in
every dimension. They failed
both with powdered felspar and
quartz. One tube formed with
pounded glass, was very nearly an
inch long, namely, -982, and had
an internal diameter of -019. When
we hear that the strongest battery
in Paris was used, and that the
effect on a substance of such easy
fusibility as glass, was to form
tubes so diminutive, we must feel
greatly astonished at the power of
a shock of lightning, which, striking
the sand in several places, has
formed a cylinder, in one instance,
of at least thirty feet long, and
having an internal bore, where not
compressed, of full an inch and a
half; and this is in a material so ex-
traordinarily refractory as quartz !"
Specimens of vitreous sand tubes
or fulgorites are contained in the
Museum of the Geological Society,
and the fifth volume of the Society's
transactions contains an engraving
of them.

FULI'GINOUS. (fuliginosua, (Lat.)/w-
ligineux,-eme, Fr. fulligin6so, It.)
Sooty ; dark ; smoky ; dusky ; of
the colour of soot.

FU'LLER'S-EABTH. A marl of a close
texture, soft and unctuous, con-

taining about 25 per cent, of alu-
mina. It derives ita name from
its being used by fullers to take
the grease out of cloth before they
apply soap. Any clay having its
particles of silica very fine, may be
considered as fuller's earth ; for it
is the alumina alone which acts
upon the cloth, on account of its
strong affinity for greasy substances.

FUNGIA. A genus of stony, free poly-
pifers, simple, orbicular, or oblong;
convex and lamellated in the upper
part with an oblong central groove,
concave and rough beneath. Many
species have been identified.

FU'NGIFORM. Having its termination
resembling the head of a fungus :
certain substances are occasionally
found of this shape, as calcareous
stalactites, &c.

FU'NGUS. (Lat. fungus.'] One of
the orders of the class Cryptogamia,
according to the artificial system of
Linna3us. A mushroom; an ex-
crescence from trees or plants not
naturally belonging to them; any
morbid sponge-like excrescence.

FD'NNEL-SHAPED. In botany, applied
to a monopetalous corolla, having
a conical border placed upon a tube.
A form which gradually increases
in thickness towards its apex, and
scooped out, or hollowed, at its
apical margin.

FtfBCULA. (Lat.) A fork, a peculiar
formation of bone in birds, of a
fork-like shape. Thefurcula, com-
monly known as the merry-thought-
bone, is seldom wanting in birds.
It is in form like a Y, common to
both shoulders, and joined by its
point to the most prominent part
of the crista of the sternum, while
the other extremities are connected
to the humeral end of the clavicles,
and the point of the scapulae, where
these two bones are articulated with
each other, and with the os humeri.
The furcula serves to keep the wings
at a proper distance in flying, and
is strong and expanded in birds

F IT S

[184]

•which fly with great force and
rapidity. In the ostrich and casso-
wary, it is imperfect, the lateral
branches not uniting together.

The ornithorhynchus and ich-
thyosaurus both possess a peculiar
form of sternum, resembling the
furcula of birds. The echidna is
the only known land quadruped
that has a similar furcula and cla-
vicles. A cartilaginous rudiment
of a furcula occurs also in the
dasypus.

FU'SCITE. An opaque mineral of a
greyish or greenish-black colour,
found in Norway, in masses of
granular quartz.

IV SIFOBM. Spindle-shaped, swelling
in the centre with the ends taper-
ing ; intermediate between the
conical and the oval.

GAL

A subfusiform. univalve,
ventricose in its middle or lower
part, with a canaliculated base,
and no varicose sutures j an elon-
gated spire, a smooth columella,
and the lip not slit. The genus
comprises many species. The genus
fusus comprises all shells with a
salient and straight canal, which
are destitute of varices. Pusi are
found at depths varying to eleven
fathoms, in mud, sandy mud, and
sand.

IVsus CONTBA'BIUS. A species of
fusus found in the crag of Suffolk,
a sinister shell. The fusus con-
trarius, or reversed whelk, which
is synonymous with the murex
contrarius of Linna3us, appears to
be a shell characteristic of the crag
deposit.

GA'BBBO. A crystalline granular mix-
ture of labradorite, diallage, and
euphotida.

GA'DOLINITE. A mineral thus named
after Gadolin, who first ascertained
its composition. Its colour is green-
ish-black ; that of its po wder green-
ish-grey. Occcurs massive; in
granular and prismatic concretions.
Eracture conchoidal and glassy.
According to Berzelius its con-
stituent parts are yttria 45*93,
silica 24 '16, protoxide of cerium
16-90, protoxide of iron 11-34.
It was first discovered at Ytterby,
in Sweden, by Capt. Arhenius, in
white felspar ; it is found also in
Ceylon, in granite.

GA'HNITE. Thus named from Gahn ;
another name for automalite.

GAILLONE'LLA FEBBTJGI'NEA. The
name assigned to a minute ani-
malcule, the case of which is found
in bog-ore.

GA'LACTITE. (70X^7/7775, Gr.) Milk-
stone.

GA'LEA. (Lat.) A genus of echini,
found fossil only. They are dis-
tinguished by an oval base, from
which the shell rises in a vaulted,
helmet-like form.

GAL'EOLA. A genus of echinites pos-
sessing the same characters as the
galea, but differing in size. This
circumstance induced Klein to di-
vide them into two genera, but
Leske deeming a mere difference
of size as insufficient to affect the
genus, included them both under
the genus echmocorys. — Parkinson.

GA'LEATED. (galeatm, Lat.) Helmet-
shaped ; covered as with a helmet.
In botany, plants bearing fiowers
of a helmet shape, as the monk's-
hood.

GALE'NA. (galena, Lat.) A shining
metallic ore, composed of sulphur
and lead ; sulphuret of lead j lead-

GAL

L 185

G A

glance. Its colour is bluish-grey,
resembling lead. Occurs regularly
crystallized, frequently in cubes
and cubo-octahedrons. Before the
blow-pipe it decrepitates and melts,
emitting a sulphureous smell. It
is found in every lead-mine. There
are two varieties, common galena
and compact galena.

GALEEI'TES. A genus of Eadiaria :
nineteen species have been deter-
mined, all in a mineralized state,
and they have been distinguished
by various names, as scolopendrite,
bufonite, cap-stones, &c.

GALLINA'CEJE. The fourth order of
the second class Aves. So called
from their affinity with the domes-
tic cock.

GALLING. The fifth order of the
class Aves, comprising the fowl,
grouse, partridge, &c.

GALLIA'ED. } Provincial names for a

CALLIAED. ) trappean sandstone of
a hard, smooth, flinty character.

GALT. j A provincial name for a stiff

GAULT. j marl, varying in colour
from a light grey to a dark blue.
The upper and lower beds of the
green-sand are in many places
separated by the gait ; it has been
also called Folks tone Marl. The
gait abounds in fossil remains, re-
markable for their beauty, the
pearly covering of the shells being
in many instances preserved. The
gait is a member of the cretaceous
group, passing, in its lower parts,
into calcareous marl. The fossils
hitherto found in the gait belong
to forty-three species, among which
are several species of ammonites
and hamites ; nautili and belem-
nites; nuculae andinocerami; cary-
ophilleae, &c. The gait rarely ex-
ceeds 100 feet in thickness; al-
though in some parts of Sussex it
is not less than 250. It is a soil
that must rank, says Mr. Young,
among the finest in this or any
other country, being pure clay and
calcareous earth. The occurrence

of this mud, says Sir H. De La
Beche, marks a modification of the
causes that transported and brought
detrital matter to rest during the
deposit of the sands beneath the
chalk, and the area over which it
took place was considerable. The
gault is frequently composed of
clay in the upper, and marls in the
lower part, containing disseminated
specks of mica. It effervesces
strongly with acids.

GAMOPE'TALOUS. Another term for
monopetalous. Having the petals
united by their edges; a corolla,
the petals of which are all united
by their edges.

GAMOSE'PALOUS. In botany, a term
used for a calyx when the sepals of
which it is composed are all united.

GANGTJE. (Called also Matrix.) The
substance in or on which a mineral
is found.

GANISTEE. (Called also Calliard.)
The provincial name for a fine
grained silicious stone, a member
of the coal series.

GA'NOID. Belonging to the order
Ganoidial.

GANOI'DIA. (from 701/0?, Gr. splen-
dour, from the brightness of their
enamel.) The second order of
fishes, according to the arrangement
of M. Agassiz. The families of
this order are characterized by
angular scales, composed of horny
or bony plates, covered with a
thick plate of enamel. The bony
pike and sturgeons are of this order.
It contains more than sixty genera,
of which fifty are extinct. — Prof.
BucJcland.

GANOIDIAN. Shining scaled. Be-
longing to the order Ganoidia.
The ganoidian order of fishes
with the placoidean prevailed,
exclusively, in all formations till
the termination of the oolitic series,
when they ceased suddenly and
were replaced by genera of new
orders, the Ctenoidean and Cycloi-
B B

GAP

[ 186 ]

G A V

dean, then for the first time intro-
duced.— Ib.

GAP. In conchology, an opening, in
multivalves and bivalves, when the
valves are shut, as in the pholades,
myse, &c.

GARNET, (grenat, sorte depierre pre-
cieuse, $un rouge fonce, comme legros
vin, Fr. granato, It. pietrapreziosa.J
Prof. Jameson, in his system of
Oryctognosy, constitutes a family
of earthy minerals which he deno-
minates the garnet family; this
consists of Leucite, Vesuvian,
Grossular, Melanite, Allochroite,
Garnet, Grenatite, Pyrope, and
Cinnamon Stone. The precious
garnet is found in rhombic dode-
cahedrons, in mica- slate, amongst
the oldest, or primary, rocks, in
many parts of the world. It is of
a beautiful red colour, sometimes
with shades of yellow or blue.
Those from the kingdom of Pegu
are most esteemed, and it is sup-
posed that this was the carbuncle
of the ancients. It is harder than
quartz, and consists of nearly equal
parts of silex, alumine, and oxide
of iron, with traces of manganese.
Common garnets are more opaque,
of a duller colour, and less hard
than the precious garnet, though
harder than quartz. They are
abundant in similar localities in all
countries, sometimes constituting
nearly the whole mass of a rock.

GAS. The name given to all perma-
nently elastic, or aeriform, fluids,
except the atmosphere. The term
was first used by Yan Helmont,
who appears to have intended to
denote by it every thing which is
driven off from bodies in the state
of vapour by heat.

GASTE'EOPOD. Belonging to the order
Gasteropoda.

GASTEEO'PODA. (from ^aa^p, the
belly, and TTOVS, the foot, Gr.)
The third order of Mollusca ; they
have the head free, they crawl
upon the belly, or upon a fleshy

disk, situated under the belly7
which serves them as feet. They
are univalvular or multivalvular,
but in no case bivalvular. The
back is furnished with a mantle
which is more or less extended,
takes various forms, and in the
greater number of genera, produces
a shell. The tentacula are very
small, situated above the mouth,
and do not surround it, varying in
number from two to six; sometimes
they are wanting altogether. The
eyes are very small, and sometimes
wanting. Several are entirely
naked ; others have merely a con-
cealed shell, but most of them are
furnished with one that is large
enough to receive and shelter them.
Most of the aquatic gasteropoda,
' with a spiral shell, have an oper-
culum, a part sometimes horny,
sometimes calcareous, attached to
the posterior part of the foot,
which closes the shell when its
occupant is withdrawn into it and
folded up. The limax or slug is
an example of the class. Cuvier
divides this class of Mollusca into
nine orders.

GA'STBIC. (from ^aa^p, Gr. gastrique,
Pr. gastrico, It.) Belonging to the
stomach or belly.

GAULT. See Gait.

GA'VIAL. A subdivision of the genus
crocodile, characterized by the nar-
row, elongated, almost cylindrical
jaws, which form an extremely
lengthened muzzle. The muzzle
is narrow, cylindrical, extremely
elongated, and a little swelled out
at the ends. The length of the
cranium is scarcely one-fifth of the
entire length of the head. The
teeth are nearly equal, twenty-five
to twenty- seven on each side below.
The first two and fourth two of the
lower jaw pass into notches of the
upper, and not into hollows. The
cranium has large foramina behind
the eyes, and the hind feet are

G E H

[ 187]

G E

indented and palmated, like those
of the crocodiles proper.

The living species of the crocodile
family are thirteen in number.
Teeth of the fossil gavial have been
found in the Tilgate strata. Dr.
Mantell observes, " it appears that
the strata of Tilgate Forest contain
the remains of at least two, if not
four, species of crocodiles : that one
of these (that with slender curved
teeth) resembles the gavial of Caen,
and probably was about twenty-five
feet in length."

GE'HLENITE. A mineral allied to
Vesuvian, and so named after
Gehlen. A combination of silica,
alumina, lime, and oxide of iron.
It occurs in rectangular four-sided
prisms, nearly approaching in their
dimensions the form of a cube;
sometimes isolated, generally in-
vested by calcareous spar, aggre-
gated irregularly in groups, or
massive, including pleonaste. Col-
ours : various shades of grey, green,
and brown. Surface : commonly,
rough and dull ; when sufficiently
brilliant for the use of the reflective
goniometer, the crystals afford
angles of 90° in every direction.
Before the blow-pipe, when alone,
it is but little affected, with borax
it fuses into a glass coloured by
iron. Heated in muriatic acid, it
gelatinizes. — Prof. Phillips.
GE'LATINE. j (gelee, Pr. gelatwa, It.)
GE'LATIN. j A concrete animal sub-
stance ; the principle of jelly. If
a piece of the fresh skin of an ani-
mal, after every impurity is care-
fully separated, be put into a
quantity of cold water, and boiled
for some time, part of it will be
dissolved. Let the decoction be
slowly evaporated till it is reduced
to a small quantity, and then put
aside to cool. When cold, it will
have assumed a solid form, and
precisely resemble that tremulous
substance known as jelly. This is,
what is called by chemists, gelatin.

If the evaporation be carried far-
ther, the substance becomes hard,
semitransparent, breaks with a
glassy fracture, and is, in short,
that substance known under the
name of glue. Gelatine therefore
is the same with glue, only that it
is free from those impurities with
which glue is so often contaminated.
Gelatine is colourless and trans-
parent; when thrown into water
it soon swells, and assumes a gelat-
inous appearance, and gradually
dissolves away. By evaporating
the water it may again be obtained
unaltered in the form of jelly.
Cold water dissolves it slowly, but
water at a temperature of 90° rap-
idly. Gelatin is insoluble in al-
cohol.
GEM. (gemma, Lat.)

1. In mineralogy, any precious
stone. Gems may be divided into
natural and artificial; the latter
are made of what is termed paste,
coloured with different metallic
oxides.

2. In botany, the bud, a small
conoid body, covered with scales,
formed during summer on the
branches of trees, containing the-
rudiments of a future plant, or part
of a plant : some buds produce
flowers and leaves, others leaves
only, and some flowers only.

GE'MINATED. In conchology, marked
with a double elevated strias con-
necting the wreaths.

GE'MINOUS. (geminus, Lat.) Double ;
in pairs.

GE'MMIPAEOTTS. Producing buds, or
gems. The animals forming the
class Poriphora are gemmiparous.

GE'MMULE. A little bud.

GENE'EIC. } (g6n6rique,l?ic.gen6ricot

GENE'BICAL. j It.) That which
comprehends the genus, or distin-
guishes from another genus, but
does not distinguish the species.

GENI'CULATE. } (geniculatus, Lat.)

GENI'CTJLATED. j Knotted ; jointed .

GEN

[ 188 ]

G E 0

applied to culms bent like the knee ;
also to peduncles bent at the joints.

GE'NESSEE SHALE. One of the Devo-
nian rocks of America, it is a black
shale, with flagstones and sand-
stones.

GE'NUS. (Lat.)

1. That which is predicated of
many things, as the material or
common part of their essence.

2. A subdivision of any class or
order of natural beings, whether of
the animal, vegetable, or mineral
kingdoms, all agreeing in certain
common characters.

GE'ODE. (^ea^s, from yea, Gr.) A
roundish piece of mineral matter,
sometimes only an incrustation,
generally more or less hollow,
usually lined with crystals, or in
some cases loose earthy matter.
The geodes found in the greensand
near Sidmouth, says Mr. Bake well,
in his valuable Introduction to
Botany, are composed of opaque
chert on the outside, and contain
within, mammillated concretions of
beautiful chalcedony, and occasion-
ally perfect minute rock-crystals.

GEO' GNOSTIC. | Pertaining to a

GEO'GNOSTICAL. j knowledge of the
structure of the earth.

GEO'GNOSY. (from 7^ and ryz/axm, Gr.)
That branch of natural history
which treats of the structure of the
earth. Werner and his disciples,
as well as some of the French geol-
ogists, have substituted geognosy
for geology, the former derived
from 717 and <yvu)<m, the latter from
777 and Xo'^yos : for this change no
sufficient reason can be asssgned,
and it is contrary to the established
analogies of language. Nothing
can be more unmeaning than the
apologies that have been offered for
substituting ryi>a)<m, knowledge, for
Xo'^o?, reason. By the same rule
we ought to change meteorology,
physiology, &c., into meteorognosy,
physiognosy, &c. Prof. Jukes ad-
vocates the retention of the word

geognosy, and would divide geology
into three heads : — 1. Geognosy, or
the study of the structure of rocks
independently of their arrangement
into a chronological series, and he
would again divide geognosy into
lithology, and petrology. 2. Pa-
laeontology, and 3, Stromatology.
GEO'LOGY. (from 79 and XoVyos, Gr.)
Geology may be denned to be that
branch of natural history which in-
vestigates the successive changes
that have taken place in the organic
and inorganic kingdoms of nature.
It is a science founded in exact
observation and careful induction ;
it may be termed the physical
history of our globe ; it investigates
the structure of the planet on which
we live, and explains the character
and causes of the various changes
in the organic and inorganic king-
doms of nature. It has been em-
phatically termed the sister science
of astronomy, ranking, undoubtedly,
in the scale of sciences, next to
astronomy, from the sublimity of
the objects of which it treats.

Geology is as intimately related
to almost all the physical sciences,
as is history to the moral. As the
historian should, if possible, be at
once profoundly acquainted with
ethics, politics, jurisprudence, the
military art, theology ; in short,
with all those branches of know-
ledge, whereby any insight into
human affairs, or into the moral
and intellectual nature of man can
be obtained ; so is it desirable that
the geologist should be well versed
in chemistry, mineralogy, zoology,
botany, comparative anatomy; in
short, in every branch of science
relating to organic and inorganic
nature. " It was long," says Sir
C. Lyell, " ere the distinct nature
and legitimate objects of geology
were fully recognised, and it was
at first confounded with many other
branches of inquiry, just as the
limits of history, poetry, and my-

G E 0

thology, were ill defined in the
infancy of civilization."

Werner appears to have regarded
geology as little other than a sub-
ordinate department of mineralogy,
and Desmarest included it under
the head of physical geography.
Dr. Hutton, in his treatise, pub-
lished in 1795, first endeavoured to
draw a positive line of demarcation
between geology and cosmogony,
declaring that geology was in no
ways concerned with questions as
to the origin of things ; and, in fact,
geology differs as widely from cos-
mogony, as hypothesis concerning
the mode of man's first creation
differs from history. Philosophers
for some ages past neglected the
examination of the earth, content-
ing themselves with vain specula-
tions respecting its formation ; and
to Strabo, who flourished under
Augustus, and died under Tiberius,
about the year 25, and to the old
philosophers, who studied the local
phenomena of their countries, would
the title of geologists with more
propriety be given than to Burnet
and Buffon, whose systems of cos-
mogony have more the air of a
system of romance, than of a serious
generalization of facts. In tracing
the history of geology from the
close of the seventeenth to the end
of the eighteenth century, we find
the science retarded by the wild
and visionary speculations of a host
of writers ; to enter on these would,
however, far exceed the limits of a
work of this kind, and those desi-
rous of so doing, I would refer to
Sir C. LyelPs admirable work,
Principles of Geology.

Hutton, following the example
of Newton in astronomy, endea-
voured to give fixed principles to
geology; but, at that time, too
little progress had been made in the
science, to enable him to realize so
noble a project. A brighter period
has now dawned, and the following

[ 189 ] G E 0

out the only true method, namely,
that of keeping within the boundary
of inductive philosophy, has led to
the most important results.

Happily, facts have multiplied
so rapidly that geology is daily
emerging from that state when an
hypothesis, provided it were bril-
liant or ingenious, was sure of ad-
vocates and temporary success, even
when it sinned against the laws of
physics and facts themselves.

One of the greatest difficulties
with which geology has had to
contend, is the false notion enter-
tained by many well-meaning but
weak persons, that geology was
opposed to Scripture revelation,
and that geological researches
might prove injurious to religion.
Unfortunately prejudice and ignor-
ance have too frequently called in
the aid of religious feeling to thwart
and oppose the progress of scientific
knowledge ; and it is too much to
be feared that did the same power
now exist, the geologists of the
present day might suffer the same
persecutions that Gallileo Gallilei
did, and that the works of Lyell,
Buckland, De la Beche, Conybeare,
Hurchison, Phillips, Sedgwick,
Mantell, and a host of others, would
swell the catalogue of the forbidden
list.

Why, it may be asked, should
persons whose opinions are founded
on the basis of immutable truth
fear the elicitation of truth? or
what has religion to fear from the
minutest, the most searching, in-
vestigation ? Let it ever be borne
in mind that, on the one hand,
truth can never be opposed to truth,
and, on the other, that error is only
to be effectually confounded by
searching deep and tracing it to its
source.

Nothing can be more unfounded
than the objection which has been
taken against the study of natural
philosophy, and, indeed, against all

G E 0

science, that it fosters in its culti-
vators an undue and overweening
self-conceit, leads them to doubt
the immortality of the soul, and to
scoff at revealed religion. Its
natural effect on every well regu-
lated mind is, and must be, directly
the reverse. Minds which have
long been accustomed to date the
origin of the universe, as well as
that of the human race, from an
era of about six thousand years
back, receive reluctantly any infor-
mation, which, if true, demands
some new modification of their
present ideas of cosmogony, and, as
in this respect, geology has shared
the fate of other infant sciences, in
being for a while considered hostile
to revealed religion, so, like them,
when fully understood, it will be
found a potent and consistent aux-
iliary to it, exalting our conviction
of the power, wisdom, and goodness
of the Creator. The consideration
of the evidences afforded by geolog-
ical phenomena may enable us to
lay more securely the very founda-
tion of natural theology, inasmuch
as they clearly point out to us a
period antecedent to the habitable
state of the earth, and consequently
antecedent to the existence of its
inhabitants. When our minds
become thus familiarized with the
idea of a beginning and first crea-
tion of the beings we see around
us, the proofs of design, which the
structure of those beings afford,
carry with them a more forcible
conviction of an intelligent Creator,
and the hypothesis of an eternal
succession of causes, is thus at once
removed.

" It may fairly be asked," says
Chalmers, "of those persons who
consider physical science a fit sub-
ject for revelation, what point they
can imagine short of a communica-
tion of omniscience, at which such a
revelation might have stopped,
without imperfection or omission,

[ 190 ] G E 0

less in degree, but similar in kind,
to that which they impute to the
existing narrative of Moses. A
revelation of so much only of
astronomy as was known to Coper-
nicus, would have seemed imperfect
after the discoveries of Newton ;
and a revelation of the science of
Newton would have appeared
defective to Laplace. And unless
human nature had been constituted
otherwise than it is, the above sup-
posed communication of omniscience
would have been imparted to crea-
tures utterly incapable of receiving
it, under any past or present moral
or physical condition of the human
race. Does Moses even say, that
when God created the heavens and
the earth he did more, at the time
alluded to than transform them out
of previously existing materials ?
Or does he ever say that there was
not an interval of many ages be-
tween the first act of creation, de-
scribed in the first book of Genesis,
and said to have been performed
* in the beginning,' and those more
detailed operations, the account of
which commences at the second
verse, and which are described as
having been performed in so many
days?

" Let no one, therefore, be check-
ed in his enquiries into the history
of the globe by anything but the
good rules of philosophical induc-
tion, which are essential to the
right use of the intellectual strength
which God has conferred upon
man, to be exercised on the mighty
works of nature ; and least of all
let him be deterred from the pur-
suit of truth by the vain and im-
pious dread that he may go too far,
and penetrate too deeply into those
mysteries, which, among their other
uses have this one, namely, ^that
they continually excite to activity
the soul of man; and, the more
they are studied, lead to deeper
delight, aud mere awful contem-

G E 0

[191 ]

GEY

plation of their glorious and bene-
ficent Author."

Geology reveals to us the extra-
ordinary fact that as the globe
passed from one condition to
another, whole races of animals
perished, and were succeeded by
others with organizations adapted
to the altered state of the planet.
On this phenomenon is based the
fundamental principle of the iden-
tification of strata by their imbedded
remains ; the passage from one
deposit to another being marked by
a change in the animals which
lived and died during the accumu-
lation of each. Thus, although
the fossils of any one great series
of beds possess a common character,
yet those which are found in the
lowest and highest strata of a great
formation are for the most part dis-
similar in species, and often in
genera.

Geology, aided not only by the
higher branches of physics, but by
recent discoveries in mineralogy
and chemistry, in botany, zoology,
and comparative anatomy, is en-
abled to extract from the archives
of the interior of the earth, intel-
ligible records of former conditions
of our planets, and to decipher
documents, which were a sealed
book to our predecessors. Thus
enlarged in its views, and provided
with fit means for pursuing them,
geology extends its researches into
regions more vast and remote, than
come within the scope of any other
physical science, except astronomy.
— Davy. Bucldand. Herschell. Chal-
mers. Lyell. Phillips. Mantell.
Bakewell.

GEOSATJ'ETJS. A fossil saurian of the
oolite and lias formations, discov-
ered by M. de Scemmering in the
environs of Manheim, and interme-
diate between the crocodile and
monitor. Cuvier considered the
geosaurus to constitute a new sub-
genus of the saurian order. The

specimen above mentioned is sap*
posed to have been from twelve to
thirteen feet in length.

GEEM. (germe, Fr. germe, It. germm,
Lat.) 1. In botany, the swollen
base of the pistil, forming the rudi-
ment of the fruit and seed.
2. The embryo; so long as the
offspring has no independent exist-
ence, but participates in that of its
parent, it is called a germ. The
separation of the germ is called
generation.

GEEVI'LLIA. A fossil genus of bivalve
shells; they are subequi valve, ob-
long, oblique, the hinge long,
straight, having small irregular,
transverse, ligamentary pits, and
likewise a series of parallel internal
ribs. The general form resembles
avicula, the umbo having an auricle
on each side. Five species are
known as belonging to the carbon-
iferous, seven to the Jurassic, and
five to the cretaceous strata of the
British Isles. — Lycett.

GET' SEE. The name given to certain
boiling springs or fountains in
Iceland. The water of these
geysers holds a considerable pro-
portion of silex in solution. " These
intermittent hot springs occur in a
district situated in the south-west"
ern division of Iceland, where
nearly one hundred of them are
said to break out within a circle of
two miles. They rise through a
thick current of lava which may,
perhaps, have flowed from Mount
Hecla, the summit of that volcano
being seen from the spot at a dis-
tance of more than thirty miles.
Pew of the geysers play longer
than five or six minutes at a time,
and the intervals between their
eruptions are, for the most part,
very irregular. The great geyser
rises out of a spacious basin at the
summit of a circular mound, com-
posed of siliceous incrustations de-
posited from the spray of its waters.
The diameter of this basin is fifty-

GEY

[ 192 ]

GIL

six feet in one direction by forty-
six in another. In the centre is a
pipe seventy-eight feet in perpen-
dicular depth, and from eight to
ten feet in diameter, but gradually
widening as it rises into the basin.
The circular basin is sometimes
empty, but is usually filled with
beautifully transparent water in a
state of ebullition. During the
rise of the boiling water in the
pipe, especially when the ebullition
is most violent, and when the
water is thrown up in jets, subter-
ranean noises are heard, like the
distant firing of cannon, and the
earth is slightly shaken. The
sound then increases, and the
motion becomes more violent, till
at length a column of water is
thrown up, with loud explosions,
to the height of one or two hundred
feet. After playing for a time like
an artificial fountain, and giving
off clouds of vapour, the pipe or
tube is emptied, and a column of
steam rushing up with amazing
force and a thundering noise, ter-
minates the eruption. If stones
are thrown into the crater, they
are instantly ejected, and such is
the explosive force, that very hard
rocks are sometimes shivered by it
into small pieces," — Lyell.

Sir George Mackenzie thus de-
scribes an eruption of the Great
Geyser, " The eruption commenced
with a sound resembling the distant
discharge of a piece of ordnance ;
the sound was repeated irregularly
and rapidly, and I had just given
the alarm to my companions, (Drs.
Bright and Holland) who were at
a little distance, when the water,
after heaving several times, sud-
denly rose in a large column,
accompanied by clouds of steam,
from the middle of the basin, to
the height of ten or twelve feet.
The column seemed as if it burst,
and sinking down it produced a
wave, which caused the water to

overflow the basin in considerable
quantity. After the first propul-
sion, the water was thrown up
again to the height of about fifteen
feet. There was now a succession
of jets to the number of eighteen,
none of which appeared to exceed
fifty feet in height; they lasted
about five minutes. Though the
wind blew strongly, yet the clouds
of vapour were so dense, that after
the first two jets I could only see
the highest part of the spray, and
some of it that was occasionally
thrown out sideway. After the
last jet, which was the most furious,
the water suddenly left the basin,
and sunk into the pipe in the
centre. The temperature of the
water in the basin was ascertained
to be 209° Fahrenheit." In a sub-
sequent eruption, witnessed by Sir
George, there was a succession of
magnificent jets, the highest of
which was at least ninety feet.

Dr. Black gives the following
analysis of the waters of the geysers
of Iceland. Soda 5*56, alumina
2*80, silica 3 1 -50, muriate of soda
14-42, sulphate of soda 8-57

The siliceous deposits from the
geysers are well known. Sir G.
Mackenzie describes the leaves of
certain trees converted into stone,
every fibre being discernable.
Grasses, rushes, and peat are in
every state of petrifaction.

GI'BBOFS. (gilbus, Lat. gilleaux,
Fr. gibl6so, It.) Bossed; convex;
bunched. In botany, applied to
fleshy leaves having one or both
sides convex, arising from the great
abundance of pulp.

GI'BBSITE. A mineral of a dirty white
colour, found in America, and named
after Mr. Gibbs. Its analysis gives
alumina 64'8, water 34'7. Specific
gravity = 2'4,

GILL. The lung, or respiratory organ
of the fish. The gills, or branchia3,
lie in openings on each side of the
head; their form is semicircular;

GIL

[ 193 ]

GIL

they have a vast number of fibrillae
standing out on each side of them
like a fringe, and very much re-
semble the vane of a feather. There
are, in most fishes, four gills on each
side, resting on an equal number of
arched portions of cartilage or bone,
connected with the os hyoides. In
some cartilaginous fishes there are
five gills on each side ; in the lam-
prey there are seven. The larger
Crustacea have their branchiae situ-
ated on the under side of their
body, not only in order to obtain
protection from the carapace, which
is folded over them, but also for
the sake of being attached to the
haunches of the feet, jaws, and
thoracic feet, and thus participating
in the movements of those organs.
They may be seen in the lobster
and in the crab, by raising the
lower edge of the carapace.

In the greater number of mollusca
these important organs, although ex-
ternal with respect to the viscera, are
within the shell, and are generally
situated near its outer margin. They
are composed of parallel filaments,
arranged like the teeth of a fine
comb; and an opening exists in
the mouth for admitting the water
which is to act upon them. These
filaments appear, in many instances,
to have the power of producing
currents of water in their vicinity
by the action of minute cilia, sim-
ilar to those belonging to the ten-
tacula of many polypi, where the
same phenomenon is observable. In
the Acephala, or bivalve mollusca,
the gills are spread out, in the form
of lamina?, round the margin of the
shell, as is exemplified in the oyster
where it is commonly known by the
name of beard. The aerated water
is admitted through a fissure in the
mouth, and when it has performed
its office in respiration, is usually
expelled by a separate opening.

All the sepise have their gills
enclosed in two lateral cavities,

which communicate with a funnel-
shaped opening in the middle of
the neck, alternately receiving and
expelling the water by the muscular
action of its sides. The forms as-
sumed by the respiratory organs in
this class are almost infinitely di-
versified. In fishes the gills form
large organs, and the continuance
of their action is more essential to
life than it appears to be in any of
the inferior classes. When their
surfaces are minutely examined,
they are found to be covered with
innumerable minute processes,
crowded together like the pile of
velvet ; and on these are distributed
myriads of blood-vessels, spread
like a delicate net- work, over every
part of their surface. A large flap,
termed the operculum, extends
over the whole organ, defending it
from injury, and leaving below a
wide fissure for the escape of the
water, which has performed its
office in respiration. For this pur-
pose the water is taken in by the
mouth, and forced by the muscles
of the throat through the apertures
which lead to the branchial cavities;
in this action the branchial arteries
are brought forward and separated
to a certain distance from each
other, and the rush of water
through them unfolds, and separ-
ates, each of the thousand minute
filaments of the branchiae, so that
they all receive the full action of
that fluid as it passes by them.
When a fish is taken out of the
water, the animal vainly reiterates
its utmost efforts to raise the bran-
chiae, and relieve the sense of suffo-
cation it experiences in consequence
of the general collapse of the fila-
ments of those organs, which adhere
together in a mass, and can no
longer receive the vivifying influ-
ence of oxygen. "It has been
generally stated," says Dr. Roget,
"by physiologists, even of the
highest authority, that the princi-

c c

GIN

L 194]

G L A

• pal reason why fishes cannot main-
tain life, when surrounded by air
instead of water, is that the bran-
chiae become dry, and lose the
power of acting when thus deprived
of their natural moisture. The
rectification of this error is due to
Mourens, who pointed out the true
cause."

GI'NGLYMOID. (from wfavpos and
e$>os, Gr.) Resembling a hinge;
pertaining to that species of hinge-
like joint which admits of flexion
and extension.

GI'BASOLE. (from ^yro, to turn, and
sol, the sun, Lat.) The name
given to a variety of opal. The
silex girasol of Brongniart, and
quartz resinite girasol of Haiiy.
The girasole is of a milk-white
colour, but it possesses a remark-
able property of reflecting a red
colour when turned towards the
sun, or any bright light. From
this peculiar property it obtained
its name. Girasole is sometimes
strongly translucent, and the finest
specimens resemble translucid jelly.

GLA'CIEB. (glacier, Fr. Amas de
montagnes de glace, qui se trouvent
en quelques endroits de la Suisse de la
Savoie ei du Dauphine, au sommet des
montagnes. J Great accumulations or
extensive fields of ice, common
in mountainous countries. The
presence of glaciers depends on the
accumulation of a large mass of
snow, subject to variations of
temperature sufficient partially to
thaw and then to reconsolidate the
mass in its downward course. They
have been compared, aptly enough,
to gigantic icicles. At Mont Blanc,
the glacier of Montanvert is said
to descend 1,200 feet below the
summit of the mountain. " I was
much struck," says Mr. Darwin,
" by observing the great difference
between the matter brought down
by torrents and by glaciers : in the
former case a spit of gravel is
formed, but in the latter a pile of

boulders." Glaciers are instru-
ments of the degradation of land,
inasmuch as they drive before them
and transport such substances as
they may have power to move. In
front of glaciers there is generally
a pile of rubbish, composed of
pieces of rock, earth, and trees,
which they have forced forward,
known in Switzerland by the name
of moraine. If there be a line of
moraine some distance from the
front of the glacier, it is considered
that the glacier has retreated to
the amount of that distance ; but
if there be no other than that
which the glacier immediately
drives before it, it is considered to
be on the increase.

GLA'CIAL DEPOSITS. These consist of
clays, sands, and gravels, sometimes
stratified, sometimes rudely piled
together, and containing great
blocks of rock. These deposits are
generally known as "drift," and
" erratic block groups."

GLANCE, (giants, Germ.)

1 . A name given to some minerals
which possess a metallic, or pseudo-
metallic lustre.

2. An order of minerals, containing
eight genera. — 1. Copper-glance;
2. Silver-glance; 3. Lead-glance;
4. Tellurium-glance ; 5. Moly-
bdena-glance ; 6. Bismuth-glance;
7. Antimony-glance; 8. Melane-
glance.

GLANCE-COAL, (glanzkohle, Germ.) A
variety of coal, known also as an-
thracite. This is the glanzkohle of
Werner, the glance-coal of Jameson,
the native mineral carbon of Kir-
wan, and the blind-coal of some
authors. There are several varie-
ties of the glance-coal, namely, con-
cJioidal glance-coal, or that having
a conchoidal fracture and splendent
lustre; slaty glance-coal, or that
with a slaty structure; columnar
glance-coal, and fibrous glance-coal.
This combustible, at first view,
strongly resembles coal, from which,

G L A

G L A

however, it materially differs. Its
colour is black, or rather grayish
and iron-black, sometimes tinged
with blue or brown. It, perhaps,
never possesses the pure deep black
of coal. Glance-coal, like the dia-
mond, appears to be essentially
composed of pure carbon, but in a
very different state of aggregation.
The glance-coal of Kilkenny con-
tains about 97 per cent, of carbon ;
that of Rhode Island about 94 or
95. It occurs in beds in the coal
formation, in the secondary class of
rocks; it is occasionally found
among rocks of the primary and
transition series. It is sometimes
nearly allied to graphite. It may
be distinguished from coal by the
difficulty with which it burns, by
its greater specific gravity, and by
its composition : it differs from
graphite in being less heavy; its
trace on paper is dull and blackish,
whereas that of graphite is a shin-
ing metallic gray ; and graphite is
unctuous to the feel, whereas
glance-coal is not.
GLAND, (glande, Fr. glandula, It.)
1 . Bodies employed to form or alter
the different liquids in the animal
body. There are two distinct sets
of glands, the conglobate, and the
conglomerate. Great variety is
observable both in the form and
structure of different glands, and in
the mode in which their blood-
vessels are distributed. In some
glands, the minute arteries suddenly
divide into a great number of
smaller branches, like the fibres of
a camel-hair pencil ; this is called
the pencillated structure. Some-
times, the minute branches, instead
of proceeding parallel to each other,
after their division, separate like
rays from a centre, presenting a
stellated arrangement. In the
greater number of instances, the
smaller arteries take a tortuous
course, and are sometimes coiled
into spirals. It is only by means

of microscopic aid that these
minute structures can be rendered
visible.

2. In botany, a small transparent
tumour or vesicle, discharging a
fluid, either oily or watery, and
situated on various parts of plants,
as the stalk, calyx, leaves, &c.
These glands are composed of
closely compacted cells, which
perform the functions of secretion,
or the conversion of the nutritious
juices into particular products
required for various purposes in
the economy of the plant. The
perfume of the flowers and leaves
of plants arises from secretions from
glands.

GLANDI'FEROUS. (from glandifer, Lat.)
Bearing acorns, or fruit resembling
acorns.

GLA/NDULAH. } (glanduleux, Fr. glan-
GLA/NDTTLOUS. ) duloso, It. glandu-
losits, Lat.)

1. Pertaining to glands; contain-
ing glands ; full of glands.

2. In botany, applied to the
margins of leaves having glands.

GLA/NDULOFS GNEISS. A variety of
gneiss, (in which the mica is some-
times arranged in undulated layers,)
presenting numerous small masses
of felspar or quartz, of a globular
or ellipitical form, interspersed like
glands through the mass. From
this circumstance it has obtained
its name.

GLASSY PUMICE. The Glasiger Bim-
stein of Werner and Harsten. A
subspecies of pumice, for a de-
scription see Pumice.

GLAU'BBEITE. An hydrous sulphate
of soda and lime. A mineral of a
white or yellow colour; crystal-
lised in oblique four-sided prisms ;
consisting of 51 parts sulphate of
soda, and 49 parts sulphate of
lime. It is less hard than carbo-
nate of lime, but scratches sulphate
of lime. It is found in New
Castile, in Spain, disseminated in
muriate of soda.

G L A

[ 196 ]

G L U

GLA'UCONITE. Called also firestone.
The Glauconie crayeuse of the
French geologists. This comprises
the chalk-marl, without any inter-
mixture of green particles, as well
as the limestone, called in Sussex
malm-rock, and the sands and
arenaceous marls and limestones
full of green particles of sil-
icate of iron, and termed the
wpper green sand and firestone. —
Mantell.

GLAUCON'OME. A genus of fossil
corals. Under this name Goldfuss
has described five fossils, four of
which, according to De Blainville
and Milne Edwards, belong to the
genus Vincularia, previously estab-
lished by De France. The fifth
species, common at Dudley, pos-
sesses, however, characters essen-
tially different from those of Vin-
cularia, and even from those
assigned by Goldfuss. Instead of
the stem being impressed on all
sides with rows of cells, it has them
only over half the surface, the other
half being striated longitudinally. It
is probable, adds Sir R,. Murchison,
that the position of the fossil in
the matrix prevented that author
from detecting the true characters
of the coral.

GLATJ'COTJS. (glaucus, Lat. azure,

<y\ew«:os, Gr.)

1. Of a sea-green colour ; grey or
blue ; azure.

2. In botany, applied to the leaves
or stems of plants, when covered
with a fine mealiness of a sea-green
colour.

GLI'MMEB. (Germ.) The name given
by Werner to mica.

GLO'BTJLUS. A genus of fossil univalve
shells, belonging to the family of
the NaticaB ; as their name implies,
they are remarkable for their
globose figure and minute spire.
Eight species have been procured
from the English tertiary forma-
tions, and three from the carboni-
ferouslimestone and shale. — Lycett.

GLOM'ERIS. (from glomero, Lat. to
gather into a round heap.) A
myriapod, resembling a wood-louse,
which, like the armadillo, when
alarmed, rolls itself up into a
spherical ball.

GLOSSOPTE'BIA. The name proposed by
Brongniart for a genus of fossil
ferns, whose elongated leaves or
fronds are covered by fine arched
dichotomous, often anastomosing,
nervures. Specimens are met with
in the carboniferous and oolitic
strata.

GLO'TTIS. (from ryA^-ira, Gr.) The
upper opening of the larynx, at the
root of the tongue.

GLTJCI'NA. (from ry\vKv?} Gr. sweet.)
An earth obtainable from the eme-
rald, beryl, and euclase, of all
which it forms a constituent part.
Sir H. Davy discovered that glu-
cina consisted of three parts gluci-
num and one part oxygen. Glucina
is soluble in the liquid fixed
alkalies, in which respect it agrees
with alumina. It is insoluble in
ammonia, but soluble in carbonate
of ammonia. It combines with all
the acids, and forms with them
sweetish salts, from which circum-
stance it obtained its name. It
was first discovered by Vauquelin
in 1798.

GLUCINE. (from 7X^5, sweet, Gr.)
An earth composed of oxygen 30,
and glucinum 70. "When pure it
is a white powder, soft and some-
what unctuous ; specific gravity
nearly 3.

GLUCI'NTTM. The metal which is the
base of the earth glucina ; it has
not yet been obtained in a separate
state.

GLUME. (gluma> Lat.) The husk of
corn ; the chaff ; the outer husk of
corn and grasses ; the calyx of corn
and grasses. In the grasses, and
plants resembling them, the floral
envelopes are not called calyx and
corolla, but bractese. The two
outer bracteae are termed glumes.

G L U

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G

GLTJMI'FERJS. The first order of the
fourth class, Endogens, comprising
the grasses, &c.

GLUTI'NOTTS HAG. Called also the
ramper eel, or poisonous ramper.
The name assigned to a species of
suctorii. "The suctorii, one of
which, the glutinous hag, has
scarcely any brain." This creature
was regarded by Linnaeus as be-
longing to the class vermes.

GLYCE'MERIS. j A transverse bivalve,

GLYCI'MERIS. ) gaping at both ex-
tremities; hinge callous, without
tooth. Fossil and recent.

GLYPTOLE'PIS. (from 7\v7rro<?, carved,
and \c7ri?, scale, Gr.) A genus of
ichthyolites found in the lower old
red sandstone. The characteristic
parts of the creature are its scales,
these are of great size compared
with that of the animal. One
specimen, not more than half afoot
in length, exhibits scales three-
eights of an inch in diameter. In
another specimen there are scales
a full inch across, and yet the
length of the ichthyolite to which
they belonged appears not to have
exceeded a foot and a half. Each
scale consists of a double plate, an
inner and an outer. The structure
of the inner is not peculiar to the
family or the formation ; it is
formed of a num'ber of minute
concentric circles, crossed by still
minuter radiating lines. The outer
plate presents an appearance less
common. It seems relieved into
ridges that drop adown it like
sculptured threads, some of them
entire, some broken, some straight,
some slightly waved; and hence
the name given to this ichthyolite.
There are several species. — Hugh
Miller.

GLYPTO'POMUS. An ichthyolite of the
old red sandstone, known also as
Platygnathus.

GNEISS. The name given by the
German mineralogists to a schistose
or slaty granite, abounding in mica.

It is a member of the metamorphic
rocks. By some geologists, gneiss
has been called secondary granite.
Granite frequently may be observed
passing by scarcely perceptible
gradations into gneiss : when
granite contains but little felspar,
and the proportion of mica is
increased, the mica being arranged
in layers, it becomes schistose, and
we find a true gneiss. Again, when
the mica becomes very abundant,
gneiss passes into mica-slate.
Gneiss occurs in Ireland and Scot-
land ; but it is rarely found in
England or "Wales. It is most abun-
dant in Sweden. Gneiss is com-
posed of the same ingredients with
granite, namely, felspar, quartz,
and mica, its texture being equally
crystalline. According to the Hut-
tonian theory, the materials com-
posing gneiss were originally de-
posited from water, but from the
influence of subterranean heat,
became altered, so as to assume a
new texture. The structure of
gneiss is always more or less dis-
tinctly slaty, when viewed in the
mass, although individual layers
may possess a granular structure.
When this mineral is broken per-
pendicularly to the direction of its
strata, its fracture has commonly a
striped aspect. This rock, though
slaty in its structure, is rarely per-
fectly fissile. Gneiss, like granite,
never contains any fossil remains ;
when it occurs with granite, it
usually lies immediately over the
granite ; or, if the strata be highly
inclined, it appears rather to rest
against the granite than to be
incumbent upon it. Gneiss -is more
or less distinctly stratified, and the
strata are often inclined to the
horizon at a very great angle;
indeed, they are sometimes nearly,
or quite, vertical. Mountains com-
posed of gneiss are seldom so steep
as those of granite, and their sum-
mits, instead of presenting those

G 0 L

r

needle-like points, or aiguilles,
which characterize granite moun-
tains, are usually rounded. It
has been remarked, with much
truth, that abruptly conical hills
are characteristic of the formation
which Humbolt designates as
gneiss-granite. Pew of the primary
rocks are so metalliferous as gneiss.
Its ores occur both in beds and
veins : more frequently in the
latter.

GOLD. (Sax.) A metal, when pure,
of a rich yellow colour : specific
gravity 19-3. It does not readily
combine with oxygen ; hence it
does not rust when exposed to the
air, and it may be melted and re-
melted frequently with scarcely
any diminution of its quantity. : It
is said to have been kept in a state
of fusion for nearly eight months
without undergoing any perceptible
change. In ductility and mallea-
bility it surpasses all other metals,
and it may be beaten into leaves so
exceedingly thin, that one grain of
gold shall cover fifty-six square
inches, such leaves having the
thickness only of one 282,000th
part of an inch. Its tenacity is
inferior to that of iron, copper,
platinum, and silver. Gold is solu-
ble in nitre-muriatic acid, and in a
solution of chlorine. The gold
coins of this country contain one-
twelfth part of copper alloy : jew-
eller's gold is a mixture of gold and
copper, in the proportions of three-
fourths of pure gold and one-fourth
of copper.

GONI'ATITES. A sub-genus of am-
monites, in which the last whorl
covers the spire. Seven species
have been found in the carbonifer-
ous system, and seventeen in the
primary strata.

GONIO'METER. (from ^wvta, an angle,
and fierpov, a measure, Gr.) An
instrument invented by M. Caran-
geau, for the accurate measurement
of crystals. Dr. Wollaston also

8 ] G 0 N

invented a goniometer called the
reflecting goniometer ; this is a very
superior instrument. There are
two kinds of goniometers, the plain
and the reflecting. Of the latter
Mr. Phillips says, " in almost every
instance in which I have tried it
upon the planes produced by good
fractures, the success has been com-
plete. The great value of this in-
strument, which may be used with
readiness and ease, demands the
attention of every one who has the
slightest pretension to crytallo-
graphical research. The reflecting
goniometer is of great use to the
geologist, as well as to the miner-
alogist. He finds those rocks which
are termed primary, and many of
those which are called transition,
to consist, not of one homogenous
mass, but of two or more minerals,
so intermixed and associated that a
reference to the chemist is of little
avail to him : by such means he
may indeed become informed
whether a particular earth or alkali
is to be found in the mass, but the
various substances of which it is
compounded are often too minute,
and therefore too intimately associ-
ated with the others, to allow of a
determination as to which of the
component substances may contain
the earth or the alkali so discovered.
Hence structure, if it exist, becomes
a character of essential importance,
for it will be found that fragments
far too minute for analysis will
often afford brilliant planes, well
adapted to the use of the reflecting
goniometer.

The surfaces produced by cleav-
age are sometimes very small, and
therefore are not adapted to the
common goniometer ; while for the
reflecting goniometer, it matters
not if the surface be small, provided
it be perfect and brilliant ; a sur-
face of the 100th part of an inch in
length and breath will suffice.
GONYLE'PTES. A genus of the second

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order of Pseudorachnidans, the
posterior legs exhibiting a rapto-
rious character.

GORGO'NIA. A genus of Ceratophyta,
of the family Corticati, class Polypi.
These animals have a horny skele-
ton, are carnivorous, feeding upon
living animalcules. The polypi of
several species have been observed,
and they are found to possess eight
denticulated arms, a stomach, &c.
To a species found fossil in the Wen-
lock limestone, Mr. Lonsdale has
assigned the specific name assimilis ;
he says, " it is impossible to deter-
mine if this fossil be a true Gorgo-
nia, but from its great resemblance
to the axis of some existing species,
I have ventured to place it in that
genus." Mr. Lonsdale thus de-
scribes G. Assimilis : — axis round,
branched, striated longitudinally,
branches anastomosed, no project-
ing papilla, or impressed pores. —
Murchison's Silurian System.

GO'SSAN. In mining, a technical term
for an ochreous substance which,
from its appearance, may be termed
an argillaceous oxyd of iron. The
presence of gossan is considered by
the miner to be an indication of
neighbouring riches, and is de-
nominated kindly, or very kindly,
in proportion to the darkness of its
hue, and the loosenesss of its
texture.

GRA'LL^:. j An order of aquatic

GRA'LLATORES. j birds. Waders ;
frequenting marshes and streams ;
having long naked legs ; long neck ;
cylindrical bills. In this order are
included the crane, stork, heron,
bittern, &c. &c.

GRA'MINA. fgramen, Lat.) The
fourth order in Linnasus's division ;
the grasses.

GRAMINIVOROUS, (from gramen, grass,
and voro, to devour, Lat.) Sub-
sisting wholly on grass or vegetable
food. Animals which subsist whol-
ly on vegetable food are called
graminivorous, while those which

live on flesh alone are called carni-
vorous ; those feeding on both are
called omnivorous; while those
feeding solely on fishes are denomi-
nated piscivorous.

GRA'MMATITE. (The name given by
Brongniart to Tremolin.) A min-
eral, a variety of hornblende, con-
fined almost entirely to primary
rocks. Colours white and blue.
Disposed in fibrous, radiated, and
granular concretions.

GRA'NATINE. A name given by Mr.
Kirwan to a granular aggregate
containing three ingredients, but
those differing from the ingredients
of granite. A compound embra-
cing two ingredients only, he
termed a granitell; when three
ingredients are present, but not
the three forming granite, he called
it a granatine; when more than
three ingredients form the com-
pound, he termed it a granilite.

GRA'NATITE. } The Prismatoidischer

GRE'NATITE. j granat of Mohs, Gra-
natit of Werner, Staurotide of
Haliy. A reddish-brown mineral,
occurring in primary rocks in the
Shetland Isles, and in many parts
of Scotland, aud in America. Ac-
cording to Yauquelin, it consists of
alumina 45, silica 33, oxide of iron
13, oxide of manganese 4, and
lime 4. Its form and infusibility
distinguish it from the garnet.
See Staurotide.

GRANI'FEROUS. (fromgranum and/m>,
Lat.) Pods which bear seeds like
grains.

GRA'NILITE. An aggregate containing
more than three constituent parts ;
thus named by Mr. Kirwan.

GRA'NITE. (granito, It. granit, ou
granite, Fr. Pierre fort dure, qm est
composte d'un assemblage d'autres
pierres de differ entes couleurs.) An
aggregate of felspar, quartz, and
mica, whatever may be the size or
figure of the several ingredients, or
their relative proportions, is de-
nominated granite. Felspar is

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generally the predominating, as
mica is "the least considerable in-
gredient of the rock. In some
varieties the quartz is wanting ; in
others the mica; these varieties
have received particular names.
There are many varieties of granite;
as porphyritic granite, in which
large crystals of felspar occur ;
sienitic granite, in which horn-
blende supplies the place of mica ;
chloritic, or talcy granite, composed
of quartz, felspar, and talc or
chlorite, instead of mica ; felspathic
granite, &c. &c. Granite is a
compound plutonic or igneous
rock, unstratified and crystalline,
of a granular structure, whence its
name. Prom its great relative
depth, granite is rarely met with
but in mountainous situations,
where it appears to have been
forced through the more superficial
covering. "It was at one time
supposed that granite was peculiar
to the lowest portions of the rocks
composing the crust of the earth,
and that, in fact, it constituted the
fundamental rock upon which all
others had been formed, and was not
discovered higher in the series. This
opinion has given way before facts,
for we find granitic rocks in situ-
ations where they must have been
ejected subsequently to the period
during which the cretaceous group
was deposited, as also in other
places, into which they must have
been thrust at intermediate periods
down to the oldest rocks inclusive."
Granite is said to contain forty-eight
per cent, of oxygen. Granite being
an igneous rock, no organic fossil
remains could be expected to be
found therein, nor have any
ever been discovered ; nevertheless
granite is occasionally found over-
lying strata containing fossil or-
ganic remains, as in Norway; a
mass of granite has been discovered
superincumbent on secondary lime-
stone, which contains orthocerata,

&c. From these circumstances
there can no longer exist a doubt
but that granite has been formed
at different periods, and is of
various ages. A comparatively
modern granite may be observed in
the Alps penetrating secondary
strata, such secondary strata con-
taining fossils, such as belemnites,
referrible to the age of the English
lias. Although granite has often
pierced through other strata, it has
seldom, or ever, been found to rest
upon them, as if it had overflowed.
Granite almost invariably consti-
tutes the central ridges of mountain
chains, occupying the highest and
the lowest position in their strati-
fication. That it has been forced
up by some violent convulsions of
nature, which have shaken our
planet to its very centre, is beyond
doubt. The indented ridges, the
ragged precipices, the bristling
peaks, by which these chains are
characterised, prove to demonstra-
tion the violence exerted in their
production. In this respect they
present a marked contrast to those
more convex mountains, and undu-
lating ridges of hills, whose mass
was quietly deposited by the last
retiring sea, and has subsequently
remained undisturbed by any violent
revolution. Felspar is by far the
largest constituent of granite, and
in some kinds it is found in large
whitish crystals of irregular forms,
occasionally of one or two inches in
length. Granite of this kind, how-
ever beautiful it may be to the
eye, is not well adapted for
buildings, the felspar being subject
to decomposition from the continued
action of the atmosphere. Water-
loo-bridge is unfortunately built of
this perishable kind of granite. It
may be considered as a general law,
that wherever granite rises to any
height above the surface of the
earth, the strata of other surround-
ing rocks rise towards it. The

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highest point at which granite has
been discovered in any part of the
world is Mont Blanc, 15,683 feet
above the level of the ocean. Saus-
sure, who has published an account
of his ascent of Mont Blanc, infers
from his observations that the
verticals beds of granite were origi-
nally horizontal and have been
upheaved by some violent convul-
sions of nature, and he states that
what now forms the summit of the
mountain must at some former
period have been more than two
leagues below the surface.

GRA'NITEL. j A name given by

GRA'NITELL. j Kirwan to a bi-
nary aggregate composed of any
two of the following ingredients :
felspar, mica, shorl, quartz, garnet,
steatite, hornblende, jade.

GRANI'TIC AGGREGATE. A granular
compound, consisting of two, three,
or four simple minerals, among
which only one of the essential
ingredients of granite is present.
Among the granitic aggregates,
which contain only one of the
essential ingredients of granite,
may be enumerated combinations
of quartz and hornblende, — quartz
and actinolite, — felspar and schorl,
— mica and hornblende, — quartz,
hornblende, epidote, &c. &c.

GRANITI'FEROUS. All rocks admit of
a twofold division, namely, into
the primary or granitiferous, and
the secondary or derivative classes.
The granitiferous rocks comprise
various series of massive and
schistose rocks, which are not
fragmentary, nor fossiliferous, and
which are always inferior, in their
original position, to those of the
secondary class. — Boase.

GRA'NITINE. An aggregate of three
mineral constituents, one or more
differing from those which compose
granite. For example, an aggre-
gate of quartz, felspar, and shorl
is a granitine, as is one of quartz,
mica, and shorl ; or quartz, horn-

blende and garnet; and many
others.

GRANI' VOROTJS. (from granum and voro,
Lat.) Eating grain ; subsisting
on grain.

GRA'NULAR LIMESTONE. A subspecies
of carbonate of lime, the result of
a confused or irregular crystalliza-
tion. Structure foliated and gran-
ular. The grains are of various
sizes, from coarse to very fine,
sometimes, indeed, so fine that the
mass appears almost compact. When
these grains are white and of a
moderate size, this mineral strongly
resembles white sugar in solid
masses. Its fracture is foliated,
and when the structure is very
finely granular, the fracture often
becomes a little splintery. It is
more or less translucent, but in the
dark-coloured varieties, at the ed-
ges only. Its colour is most com-
monly white or gray, often snow-
white, and sometimes grayish black.
Some varieties are flexible when
sawn into thin slabs. Granular
limestone is sometimes a pure car-
bonate of lime. It occurs in very
large masses, and is almost exclu-
sively found in primary rocks;
sometimes it occurs among second-
ary, but then its relative age is
easily determined by the shells it
contains, or the accompanying min-
erals. In the Pyrenees vertical
beds of granular limestone alternate
with granite and trap, or the
limestone is sometimes intermixed
with those rocks.

There are few countries in which
granular limestone is not found.
Italy and Greece furnished the
ancients with valuable quarries.
Both granular and compact lime-
stone furnish numerous varieties of
marbles, but those which belong to
the former exhibit a more uniform
colour, are generally susceptible of
a higher polish, and are consequenty
most esteemed for statuary and
other purposes.

D D

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GEANULA'TION. {granulation, Fr.)

1. The operation by which metals
are reduced into small grains.

2. The act of forming into bodies
resembling aggregates of grains.

GBA'NTJXITE. A crystalline aggregate
of quartz and felspar, in which the
quartz occurs in thin flakes.

GEA'PHIC GEA'NITE. Called also Peg-
matite. A variety of granite, compo-
sed of felspar and quartz, so arran-
ged as to produce an imperfect
laminar structure. When a section
of graphic granite is made at right
angles to the alternations of the
constituent minerals, broken lines,
resembling Hebrew characters, pre-
sentthemselves; hence its derivation .

GEA'PHITE. Another name for black-
lead, or plumbago ; carburet of
iron. Graphite is of a dark steel-
gray, or nearly iron-black. It
leaves on paper a well denned,
shining trace, which has very near-
ly the colour of the mass, and con-
sists of minute grains. It is per-
fectly opaque, easily scraped by a
knife, and soils the fingers. It is
a conductor of electricity, and when
rubbed on sealing-wax till a metal-
lic trace appears, communicates no
electricity to the wax. Specific
gravity from 1-98 to 2'26. Consti-
tuent parts, carbon 92, iron 8.

GEA'PTOLITE. (graptolithus, Linnasus.)
Graptolites form a genus of the
family of sea-pens. " These pen-
like, serrated, fossils have," says
Sir E. Murchison, " a great vertical
range in the older or Protozoic
rocks, being found from the lower
part of the Ludlow formation,
down to very ancient beds in the
Cambrian system." " Very differ-
ent opinions," says the Danish
naturalist, Dr. Beck, "have been
entertained as to the place grapto-
lites hold in the series of living
beings, but that of Prof. Nilsson
may come nearest to the truth,
who conceives the graptolite to be
a polyparium of the ceratophydian

family. Yet I am more inclined
to regard them as belonging to the
group Pennatulinae, the Linnsean
Yirgularia being the nearest form
in the present state of nature to
which they may be compared. I
am now acquainted with six or
seven species of graptolites, all
occurring in the oldest fossiliferoua
strata, where they are associated
with Trilobites, Orthoceratites, &c.
This genus was established by
Linnaeus. The graptolite of the
most ancient fossiliferous rocks
occurs in greatest abundance in a
finely levigated mudstone, for it
too was a dweller in the mud." —
Hugh Miller. A fossil zoophyte,
found in the Silurian shales.
GEAVITA'TION. (gravitation, Fr. gram-
tazione, It.) The difference be-
tween gravity and the centrifugal
force induced by the velocity of
rotation or revolution : the force
which causes substances to fall to
the surface of the earth, and which
retains the celestial bodies in their
orbits; its intensity increases as
the squares of the distance decrease.
' 'Gravitation , ' ' says Mrs Somerville,
" not only binds satellites to their
planets, and planets to the sun, but
it connects sun with sun throughout
the wide extent of creation, and is
the cause of the disturbances, as
well as of the order, of nature;
since every tremor it excites in any
one planet is immediately trans-
mitted to the farthest limits of our
system, in oscillations, which cor-
respond in their periods with the
cause producing them."
GBA'VITY. (gravitt, Fr. gravitti, It.)
The reciprocal attraction of matter
on matter. The force of gravity is
everywhere perpendicular to the
surface, and in direct proportion to
the quantity of matter.
GEA'YWACKE. \ (from grauwacTce,
GEAT/WACKE. f Germ, a com-
GEAFWACKE'. k pound of grau,
GBE'YWACKE. / grey, and ivacke,

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a provincial term used by miners.)
The name given to a group of rocks,
being the lowest members of the
secondary strata. Sir C. Lyell
comprises in this group the Ludlow,
Wenlock and Dudley, Horderly and
May Hill rocks, the Builth and
Landeilo flags, and the Longmynd
rocks. The French have changed
the name grauwacke for traumate, a
word as little euphonic as the one
repudiated. Sir R. Murchison
eays " It would appear that the
Silurian loved to dwell amid the
relics of the old greywacke of
the Scottish region, as well as
along the Welsh border ; and thus
I rejoice in having substituted a
pleasing name, full of glorious
British recollections, for the foreign
term, Grauwacke." Thegrauwacke
group may be regarded as a mass
of sandstones, slates, and conglo-
merates, in which limestones are
occasionally developed. Sandstones
which mineralogically resemble the
old red sandstone of the English,
not only occupy the upper part,
but frequently also other situations
in the series. In the lower portions
of the grauwacke group, stratified
compounds, resembling some of the
unstratified rocks, are by no means
unfrequent. In speaking of ' ' grau-
wacke " Sir R. Murchison says " a
name which, until recently, com-
prehended every rock from the
roofing slates to the beds immedi-
ately beneath the old red sand-
stone. It may indeed be said that
grauwacke was at that time con-
sidered the limit, on reaching
which all stratigraphical and geo-
logical definition ceased. Thia
word should cease to be used in
geological nomenclature, and it is
also mineralogically valueless, be-
cause rocks undistinguishable from
the so called grauwacke occur both
in the old red sandstone and in the
coal measures." Sir R. Murchison
adds "I might, I believe, assert

that rock specimens, which many
mineralogists would term grey-
wacke, may be found in every
stage of the geological series, even
in the tertiary deposits." Mr.
Bake well observes, " Graywacke,
in its most common form, may be
described as a coarse slate contain-
ing particles or fragments of other
rocks or minerals, varying in size
from two or more inches to the
smallest grain." When the im-
bedded particles become extremely
minute, graywacke passes into
common slate. When the particles
and fragments are numerous, and
the slate in which they are ce-
mented can scarcely be perceived,
graywacke becomes coarse sand-
stone, or gritstone. When the
fragments are larger and angular,
graywacke might be described as
a breccia with a paste of slate.
When the fragments are rounded
it might not improperly be called
an ancient conglomerate. The old
red sandstone is a graywack, colour-
ed red by the accidental admixture
of oxide of iron; it possesses all
the mineral characters, and occupies
the geological position, of gray-
wacke. The rock, though composed
of substances of various colours,
usually exhibits some shade of gray
or brown ; it is sometimes of con-
siderable hardness, and susceptible
of a high polish. Graywacke is
often distinctly stratified, but the
strata are not usually parallel to
those of the subjacent rocks. The
common and slaty varieties often
alternate with each other, and both
are traversed by veins of quartz.
This rock is remarkably metalli-
ferous ; and its ores occur both in
beds and veins. Most of the mines
of the Hartz are contained in
greywacke.

Of the fossils of the greywacke^
zoophytes and crinoidea are the
most numerous. The trilobite is
characteristic of this era, and the

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orthocera, of which certain species
are also found in the carboniferous
limestone, but in no deposit more
recent. Some of the shells belong
to more recent genera, as the tere-
bratula. The only vertebrated re-
mains hitherto found are a few
bones of fishes.

The most abundant shells of the
grauwacke belong to Orthoceras,
Producta, Spirifer, and Terebratula.
Some orthoceratites are found of
large size, of a yard or more in
length. Productse are common in
the grauwacke as well as in the
carboniferous group, they are also
found in the zechstein or magnesian
limestone, above which they dis-
appear. Spirifers are found as high
up as the lias, and consequently
continued to exist to a later period
than Products. Terebratulae, how-
ever, have survived all the great
changes which have occurred, and
are to be found amongst existing
genera.

Graywacke abounds in Germany
and in Scotland; indeed, nearly all
the mountains of Scotland north of
the Frith of Forth are chiefly com-
posed of it. In the neighbourhood
of Mont Blanc, and in other parts
of the Alps, it oocurs at a great
elevation, forming large masses in
vertical beds.

GBA'YWACKE SLATE. A variety of
graywacke, in which the grains are
so minute as to be scarcely per-
ceptible by the naked eye.

GEEEN-EAKTH. The Griin Erde of
Werner; the Talc Zographique of
Haiiy; the Chlorite Baldogee of
Brongniart. A variety of talc,
occurring in vesicular cavities in
amygdaloid. Its colour is a plea-
sant green, more or less deep,
sometimes bluish or grayish-green,
and passing to olive and blackish-
green. Its fracture is dull, and
fine-grained earthy, or slighty eon-
choidal. It is somewhat unctuous
to the touch, and adheres to the

tongue. Easily reducible to powder.
Specific gravity 2 '63. — Kirwan.

According to Yauquelin it consists
of silex 52, magnesia 6, oxide of
iron 23 '4, alumina 7, potash 7 '4,
water 4. It is met with in the
mountainous districts of England
and Scotland. It is the mountain-
green of artists ; and, when ground
with oil, is employed as a paint.
GBEEN-SAND. (glauconie sdbletise, Fr.
grunsand, Germ.) A member of
the chalk formation, called also
Shanklin sand. The beds of sand,
sandstone, and limestone, which
form the lowermost strata of the
chalk formation, have obtained the
name of green-sand, from the cir-
cumstance of their containing a
considerable quantity of chlorite, or
green earth, scattered throughout
their substance. "The colouring
matter," says Dr. Turner, " of
green-sand sometimes appears in
the rock of its ordinary green tint,
and sometimes in grains of so deep
a green that they seem black. The
former generally occurs in sand, or
where the sandstone is porous, and
in this state an ochreous appearance
is often observed, due to the green
particles being partially decomposed
and their iron having passed into a
higher state of oxidation ; whereas
the black looking grains are met
with in a highly calcareous sand-
stone, where the texture is too firm
to admit of the percolation of water.
From either kind of rock the green
matter may be obtained by washing
with water and subsidence, since
the colouring matter subsides less
readily than grains of quartz, and
more readily than calcareous and
argillaceous substances. On re-
ducing the samples obtained to
powder, washing away the finer
particles with pure water, and
separating any adhering carbonates
by dilute muriatic acid, the colour-
ing matter is left, mixed only with
small grains of quartz. It then

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always appears in the form of
earthy particles of a deep green
tint. The green matter, when not
previously weathered, is very feebly
attacked by concentrated acids. It
gives out water when heated, and
becomes brown from its iron passing
into the state of peroxide. As it
has been supposed to owe its green
colour to the presence of phosphoric
acid, it was carefully examined,
with the view of detecting that
acid, if present. The result proved
that lime and phosphoric acid are
not essential constituents of the
colouring matter of green- sand, and
their presence must be regarded as
casual. The green particles have
been found to consist of silica 48*5,
black oxide of iron 22, alumina 17,
magnesia 3f8, water 7, and potash
some traces : M. Berthier gives of
potash 10, as found in some green
particles from near Havre." In
describing the group of deposits
to which the name of green- sand,
or Shanklin-sand, is appropriated,
geologists state that they admit of
a triple division ; the first, or
uppermost, consists of sand, with
irregular concretions of limestone
and chert, sometimes disposed in
courses oblique to the general di-
rection of the strata. The second
consists chiefly of sand, but in some
places is so mixed with clay, or
with oxide of iron, as to retain
water. The third, and lowest
group, abounds much more in
stone ; the concretional beds being
closer together and more nearly
continuous. The total thickness of
the green-sand, where it is fully
developed, is more than 400 feet.
The animal remains of the green-
sand are exclusively marine. The
fossils principally hitherto dis-
covered in the green-sand group
are, Inoceramus, Cuculla3a, Pecten,
Vermetus, Solarium, Mya, Nucula,
Natica, Nautilus, Dentalium, Bel-
emnites, Ammonites, Hamites,

Thetis, Siphonia, Corbula, Sphgera,
Trigonia, Diceras, Modiola, Avicula,
Gervillia, Terebratula, Limo, Lito-
rina, Eostellaria, Pusus, &c. The
French have denominated this for-
mation glauconie crayeuse, and
craie chloritee. It is very common
to divide the greensand into the
upper green-sand and the lower
green-sand, the two being separated
by the gault.

GREE'NSTONE. The Griinstein of
Werner; Eoche Amphibolique of
Haiiy ; the diabase of the Prench
geologists. A granular rock com-
posed of hornblende and felspar, in
the state of grains, or sometimes of
small crystals. Greenstone contains
a larger quantity of felspar than
basalt, and the grains both of
hornblende and felspar are less
amalgamated. It is a variety of
trap rock. The hornblende usually
predominates, and frequently gives
to this aggregate a greenish hue,
from which circumstance it obtains
its name. Greenstone occurs in
beds of considerable magnitude,
and sometimes forms whole moun-
tains. It often appears in conical
hills, or presents high, mural
precipices, whose fronts are fre-
quently composed of numerous
columns of various sizes, resemb-
ling basalt. Sometimes it forms
only the summits of moun-
tains. Small veins of actinolite,
epidote, felspar, prehnite, quartz,
&c., &c., frequently are found
traversing greenstone. "When
greenstone is decomposed it pro-
duces a reddish brown soil. The
presence of green-stone, even when
concealed from view, is oftentimes
declared by the reddish brown
colour of the soil, the tint varying
in depth according to the propor-
tion of the hornblende in the rock.

GEEIES-STONE. A rock composed of
quartz and mica in a peculiar state
of aggregation. Greiss-stone occurs
in Cornwall.

GEE

[206 ]

G R E

GEE':N"ATITE. Prismatoidal garnet.
See Granitite and Staurotide.

GEES DE VOSGES. " A very extensive
deposit," says De la Beche, " occurs
in the Yosges, and has thence
obtained its name. A difference
of opinion seems to exist between
M. Elie de Beaumont and M. Voltz
respecting the exact member of the
red sandstone series to which this
rock should be referred ; the former
considering it the equivalent of the
Bothe Todte Liegende, which occurs
beneath the zechstein ; the latter,
that it is the lower portion of the
red or variegated sandstone, which
rests on the zechstein. It is essen-
tially composed of amorphous grains
of quartz, commonly covered by a
thin coating of red peroxide of iron;
among which are discovered others
which appear to be fragments of
felspar crystals. The rock con-
tains quartz pebbles, sometimes
so abundantly as to present a
conglomerate with an arenaceous
cement. It is also often marked
by cross and diagonal laminae.

GEES BIGAEEE. (from two French
words, signifying a stone formed
of grains variously coloured.) The
name given by French geologists
to that member of the red sandstone
group known as the new red sand-
stone ; the hunter sandtein of the
Germans.

GEEY MAEL. (The Craie Tufeau of
French geologists.) One of the
members of the chalk formation,
placed above the firestone or upper
green sand and below the chalk
without flints. Where, as is
sometimes the case, the firestone is
absent, the grey marl is found
reposing immediately upon the
gault. In Sussex, says Dr. Man-
tell, this deposit constitutes the
foundation of the chalk hills, its
outcrop forming a fillet or zone
round their base, and connecting
the detached parts of the range
with each other.

The marl is commonly soft and
pliable, but indurated blocks occur
which possess the hardness of lime-
stone. It is of a light grey colour,
inclining to brown, and frequently
possesses a ferruginous tinge, de-
rived from oxide of iron. It con-
sists principally of carbonate of
lime and alumine, with an inter-
mixture of silica, a very small
proportion of iron, and perhaps of
oxide of manganese.

The mineralogical productions,
says the same talented author, in
his Geology of the South-east of
England, of the grey marl are few,
and offer but little variety : they
consist of various modifications of
sulphuret of iron, and crystallized
carbonate of lime. In organic
remains, the grey marl is very
rich, and these differ both in their
nature, and in the mode of their
preservation, from those of the
lower chalk above, and of the gault
beneath. Ammonites, hamites,
nautilites, turrilites, scaphites,
pectenites, madreporites, inocerami,
rostellarise, and auriculae, together
with the teeth and vertebrae of
sharks, are found in different parts
of this deposit. No parts of England
are supposed to be so rich in the
various species of turrilites as the
marl pits in the neighbourhood of
Lewes. A specimen of turrilites
tuberculata nearly two feet long,
the only instance in which traces
of a siphunculus are visible, was
discovered in the grey marl at
Middleham, near Lewes.

GEE'YSTONE. A rock of greyish or
greenish colour, composed of felspar

" and augite, the former being more
than 75 per cent, of the whole.

GREY-WEATHEES. The name given to
large boulders of siliceous sandstone.
There is a singular assemblage of
these erratic blocks in a field on
the borders of Wiltshire, not far
from Marlborough. The immense
blocks forming, as is supposed, the

G R E

[207]

G R Y

Druidical temple at Stonehenge, are
composed of this siliceous sandstone.
"Boulders of druid sandstone,"
observes Dr. Mantell, " also occur
in the shingle bed, and calcareous
deposit at Brighton, and may be
observed lying on the sea-shore in
considerable numbers, after a recent
fall of the cliff. Upon comparing
the sandstone of Stonehenge with
that of Sussex, no perceptible dif-
ference can be detected.
GKIT. The provincial term for a
coarse siliceous sandstone. Some
of the strata of this description
have been worked for mill- stones,
from which circumstance they have
been called mill-stone grit. The
mill-stone grit is an important
deposit in the north of England,
from the Coquet to the Tyne, and
on the hills between the dales of
Durham and York, from the Tyne
to the Kibble.

GBO'SSTJLAB. (from groseille, Fr. a
gooseberry, thus named from its
gooseberry green colour.) A very
rare mineral. The asparagus green
variety of dodecahedral garnet. It
is found in Siberia. Its constit-
uents are, silica 40 '50, alumina
20-10, lime 33- 80, oxide of iron
5'00, oxide of manganese 0*50.
GBO'WAN. 1. A Cornish name for a
soil formed of disintegrated granite.
The growan occupies a very consid-
erable area of the peninsula of
Cornwall, constituting no less than
three hundred thousand acres. The
fertility of the growan soil varies
greatly, and is in proportion to the
amount of felspar in the subjacent
granite. The hard growan varies
extremely in its hardness, but in
respect to its composition, it is
perfectly like the soft growan.
Some of the hard growan after
being exposed for a few months to
the weather, has dissolved com-
pletely into a soft growan. The
soft growan is nowhere hard enough
to support itself. The hard growan

is jointed in all directions.
2. Those veins that are called lodes
by the miners are divided into two
classes, those formed of granite
being called growan, and those of
porphyry elvan.

GBUM. The name given by the
miners to a dull dark red and green
impure concretionary limestone, in
parts ferruginous, each geode being
enveloped in red shale. It occurs
in the coal measures, and sometimes
attains a thickness of twenty feet.
The productus hemisphsericus and
another species are most abundant
in it, together with the corals
Lithostrotion floriforme, Syringo-
pora reticulata, and Lithodendron
irregulare. — Sir R. MurcMson.

GBYPH^E'A. (fomgryps, Lat. a griffin.)
An inequivalved bivalve ; the low-
er valve concave, terminated by a
beak, and curving upwards and
inwards; the upper valve much
smaller, like an operculum; the
hinge toothless, the pit oblong and
arched: one impression in each
valve. From the curved beak of
the shell, Linnaeus placed it among
the anomise ; but Lamarck placed
it under a distinct genus.

GBY'PHITE. ( gryphites, Lat.) A fos-
sil bivalve belonging to the ge-
nus gryphsea. This deeply-incur-
ved bivalve is so abundant in some
of the beds of lias in France, as to
have occasioned them to be called
Calcaire a gryphites. These shells
are known in this country by the
provincial name of " miller's
thumbs."

GBY'PHITE GBIT. A local term as-
signed by Sir R. Murchison to a
stratum of the inferior oolite of
Gloucestershire : it is thus named
from the prevalence in it of the
Cryphasa Cymbium.

GTTAYACAN'ITE. A newly discovered
mineral from the Cordilleras of
Chili, consisting of copper, arsenic,
and sulphur. Hardness 3*5 to 4.
Specific gravity 4'39.

G u A

[ 208 ]

GYP

GYMNOSPE'EMIA. (from 7^1/09, nudus,
naked, and aTepfia, semen, seed.)
The first order in the fourteenth
class, Didynamia, in Linnaeus's
artificial system ; having four naked
seeds in the bottom of the calyx,
with the exception of one genus,
Phryma, which is monospermous.

GYNA'NDBIA. (from <yw?}, a woman,
and avrjp, Gr. a man.) The name
of the 20th class in Linna3us's
sexual system, consisting of plants
with hermaphrodite flowers, having
the stamens growing upon the
style, or having the stamina united
with, or growing out of, the pistil,
and either proceeding from the
germen or the style. The orders
of this class are taken from the
number of the pistils, but botanists
are not agreed as to the admission
of some of them into the class.

GYNA'NDROUS. A term applied to a
particular class of plants, in which
the stamens and pistils are united.
The orders of this class depend on
the number of the anthers.

GY'PSUM. (<yvyfros, Gr. gypsum, Lat.
gypse, Fr. gesso, It.) The chaux
sulfatee of Brongniart and Haiiy.
Sulphate of lime ; it is composed of
sulphuric acid 46, lime 33, water
21. It is insoluble in acids, and
does not effervesce like chalk and
dolomite, the lime being already
combined with sulphuric acid, for
which it has a stronger affinity
than for the other acids. It pos-
sesses double refraction. There is
one variety known by the name of
anhydrite, or anhydrous gypsum,
which contains no water. Sulphate
of lime is an abundant mineral
salt, presenting itself under various
forms, crystallized or otherwise.
From gypsum is obtained plaster
of Paris, the gypsum being burnt
in a kiln, and the water thereby
driven off. The varieties of gypsum
are numerous ; the crystallized

. transparent varieties are known as
selenite j the fibrous and earthy as

gypsum; and the granular and
massive as alabaster. The salt
mines of this country afford ex-
amples of nearly all the varieties.
The white powder obtained by
exposing gypsum to a strong heat
has obtained the name of plaster of
Paris, from the extreme abundance
of this mineral in the neighbour-
hood of that capital. Its inferior
hardness, together with its chemical
characters, will serve to distinguish
it from the carbonate, fluate, and
phosphate of lime. " The gypsum
formation consists of alternating
beds of gypsum and argillaceous
and calcareous marl, which are
regularly arranged, and preserve
the same order of succession where-
ever they have been examined.
The gypsum forms three distinct
masses. The lowest consists of
thin strata of gypsum containing
crystals of selenite, which alternate
with strata of solid calcareous marl,
and with argillaceous shale. The
middle is like the lowest mass,
except that the strata of gypsum
are thicker, and the beds of marl
are not so numerous ; it is chiefly
in this mass that fossil fish are
found. The uppermost mass is the
most remarkable and important of
all j it is in some parts more than
seventy feet thick ; there are but
few beds of marl in it ; the lower
strata of gypsum in this mass have
a columnar structure. In this
upper mass of gypsum the skeletons
and scattered bones of birds and
unknown quadrupeds are discover-
ed. Remains of turtles and croco-
diles have been also found in the
same strata." For a further and
more interesting detail, see Bake-
well' s Introduction to Geology.

GYROCA'RPTJS. In botany, a genus of
plants containing few species, but
these widely distributed.

GYRO'ETJS. (from ryty>oe, round, and
o$o vs, a tooth, Gr.) A genus of
fossil fishes, established by Agassiz,

G Y E

[ 209 ]

HAL

of the family of Pycnodonts, or
thick-toothed fishes, found in the
oolite of Durrheim, in Baden.
GYRO'GONITE. (from ryv/>oe, curvus,
and 761/09, genus.) Petrified seed-
vessels of the Chara. These bodies
are found in fresh- water deposits,
and were, not very long since, sup-
posed to be microscopic shells, in-

deed they are thus described by
Parkinson, who concludes his no-
tice of them by stating, " Lamarck
observes, that it has the form of a
very small seed of some species of
lucern ; and hesitating at determin-
ing it to be really a multilocular
shell, only assumes it as such for
the present." See Chara.

E

HACKL'Y. A term used in mineralogy
to designate a fracture with a
peculiarly uneven surface, similar
for instance to that of pure copper.
This term, says Mr. Allan, relates
to a fracture which is peculiar to
the malleable metals.

HADE. A term used by miners ; to
dip.

HADE. | The dip from the perpen-

HA'DING. j dicular line of descent;
the angle of inclination of a vein.

HEMATITE. | (at/LLaThps, Gr. hama-

HE'MATITE. ) tites lapis, Lat.)
Blood-stone, an iron ore ; it occurs
in masses of various shapes, both
globular and stalactitic.

HALF-MOON SHAPED. A figure for-
med by the portion of a circle cut
off by the segment of a larger
circle.

HALINI'DA, An order, the lowest, of
the class Poriphera, and thus de-
nominated from the composition of
the skeleton, which consists of
minute silicious crystalline spicula.

HALIO'TIS. (from a\a, mare, and WTO?,
amis, Gr.) The sea-ear. A shell,
both fossil and recent, obtain-
ing its name from the exces-
sive amplitude of its aperture,
and the flatness of its spire,
whence it has been likened to an
ear. The shells of this genus are

said to be among the rarest fossils.
The recent shells are littoral, and
found adhering to roeks ; they are
very beautiful, and are remarkable
for the pearly irridescence of the
inner surface, and for the shell
being perforated along the side of
the columella by a series of holes ;
they are amongst the most highly
ornamented of all the gasteropoda.
The sea-ears protect their open
side by fixing themselves to the
rocks, and preserve a communica-
tion with the atmosphere, or water,
without elevating their shells, by
means of a line of apertures, under
the thickest margin, near the apex :
these apertures begin, when the
animal is young, near the spire,
and as it grows it stops up one
and opens another, as its occasions
require. " I have," says the Kev.
"W. Kirby, " a very large specimen,
in which there are traces of eight-
een apertures, and all but six are
stopped up." The soft parts of
the inhabitant of this shell are
eaten in some places, and are es-
teemed delicious.

HA'LITHEBITJM. The name assigned
to an extinct genus of mammalia
of the Eocene period.

HA'LOIDE. (from «\9, salt, and e?£o?,
Gr. form or appearance.) An order
of earthy and metalliferous mine-

E E

HAL

rals ; tasteless ; specific gravity from
2.2 to 3.3.

HA'LLOSITE. An earthy mineral of a
white colour with a slightly bluish
tinge, occurring with ores of lead,
zinc, and iron. Thus named by
Berthier in honour of M. Omalius
d'Halloy.

HALT'EBES. (aXr^ee, Gr. halteres,
Lat.) The poisers, so named from
their supposed use in balancing the
body, or adjusting with exactness
the centre of gravity when the
insect is flying. In those insects
which compose the order Diptera,
we meet with two organs, con-
sisting of cylindrical filaments,
terminating in a clubbed extremity;
one arising from each side of the
thorax, in the situation in which
the second pair of wings originate
in those insects that have four
wings; these are called halteres.
"Whatever may be their real utility,
they may still be regarded as rudi-
ments of a second pair of wings.
HA'MITE. (from hamus, Lat. a hook.)
A genus of fossil multilocular hook-
formed shells. Parkinson states
that the hamite has no evident
siphunculus, but this is a mistake ;
the siphuncle of the hamite, like
that of the ammonite, is placed on
the back, or outer margin of the
shell, and in some species this
marginal siphuncle has a keel-
shaped pipe raised over it. The
external shell is fortified by trans-
verse folds or ribs, which serve to
strengthen both the outer and the
air chambers. The hamite is
sometimes found of large size, more
especially that species known as
Hamites grandis ; some of them are
of the diameter of a man's wrist.
HAPLACA'NTHTJS. The name assigned
to a fossil fish of the old red sand-
stone, one species of which has been
described by Agassiz, namely, H.
Marginalis.

HAEDNESS. In mineralogy, one of
the physical or external characters

[ 210 ] EAR

used in determining minerals. To
Prof. Mohs we are indebted for a
scale easily formed, and at the
same time distinct and accurate. It
is as follows : —

1. Talc, of a white or greenish
colour.

2. Rock-salt, a pure cleavable
variety ; or gypsum uncrystallized,
and only semi- translucent.

3. Calcareous spar, any cleavable
variety.

4. Fluor spar, presenting good
cleavage.

5. Apatite, the asparagus stone
from Saltzburgh.

6. Adularia, any perfectly cleav-
able variety.

7. Rock crystal, limpid and trans-
parent.

8. Topaz, any simple variety.

9. Corundum stone from Bengal,
which affords a smooth surface
when fractured.

10. The diamond.

In employing this scale, we en-
deavour to find the degree of hard-
ness of a given mineral by trying
which number of the series is
scratched by it ; or, still better, by
passing with the least possible force
the specimens under comparison
over a very fine file. Prom the
resistance these bodies afford to the
file, from the noise occasioned by
their passing over it, and from the
quantity of powder left on its sur-
face, their mutual relations in
respect to hardness are deducible
with great correctness. When,
after repeated trials, we are satisfied
which member of the scale the
mineral is most closely allied to,
we say its hardness is equal to
seven, (suppose it to be rock crys-
tal) and write after it H. = 7*0.
If, however, the mineral under ex-
amination do not exactly correspond
with any one member of the scale,
but is found to be between two of
them, we say H. = 7'5, or 7'75 if
it approximate to the next higher

H A 11

[211]

HAS

number. The file should be cut
fine, and of the hardest steel.

HAR'MOTOME. (from apjws, a joint,
and re/aw, to divide.) The Kreutz-
stein of Werner; Cross-stone of
Jameson ; Pierre cruciform of Bro-
chant ; Staurolite of Kirwan. See
Cross-stone.

HA'BPA. A genus of shells placed by
Cuvier in the family Buccinoida,
order Pectinibranchiata, class Gas-
teropoda. A beautiful genus of
shells, distinguishable from all
others by the regular longitudinal
ribs that mark the external surface,
in some degree resembling a string-
ed instrument, from which the
name is derived. The genus is
both fossil and recent ; the shells
are marine, and are inhabitants of
•warm climates.

HA'KPAX. (Parkinson.) A proposed
fossil genus of bivalve shells found-
ed upon the well known Plicatula
spinosa of the Lower Lias. Harpax
has long since by universal consent
been merged in Plicatula ; recently
however, (1858) M. Eudes Deslong-
champs has proposed to re-establish
Harpax, in an elaborate memoir,
entitled, ' ' Essai sur les Plicatules
fossiles des terrains du Calvados,"
wherein he has figured and describ-
ed many species of Harpax from
the Jurassic rocks of Calvados ;
compared with Plicatula the dis-
tinct ionresides chiefly in the hinge,
and in the figure of the borders of
the fossa which receive the cardi-
nal teeth. — Lycett.

HASTINGS BEDS. } The name as-

HASTINGS SANDS, j signed by Dr.
Fitton to the central group of the
Wealden formation, from their
great development in the neigh-
bourhood of Hastings. The Hast-
ings beds comprise the Horsted
sand ; the Tilgate Forest strata ;
and the Worth sandstone. These
consist of numerous strata of sands
and sandstones, often ferruginous,
and occasionally intermingled with

shales. The organic remains found
in these beds are not numerous as
regards species ; they are, however,
characterized by containing bones
of the Iguanodon. The Hastings
sands attain a thickness in some
places of 400 feet and upwards.
These sandy clays, says Dr. Fitton,
have, in general, great variety of
composition and colour; being in
some places almost totally composed
of sand, — in others of clay, or Pul-
ler's earth, frequently mottled with
various shades of tea-green, and
dark purplish red. The Hastings
sands consist throughout of beds of
sand, calciferous grit, clay and shale,,
with argillaceous iron ore, and
limestone abounding in shells : and
of these, clay intermixed with sand
forms so very large a proportion,
that the name of the stratum,
might, perhaps, with equal pro-
priety, have been taken from the
former substance. Dr. Pitton gives
the following as the order of the
beds of the Hastings sands in
Sussex : —

1. Ferruginous and fawn-coloured
sands, and sand-rock, including
small linear portions of lignite,
with stiff grey loam.

2. Sand-rock, with concretional
courses of calciferous grit.

3. Dark coloured shale, ten to
twelve feet thick.

4. The white sand-rock of the
Hastings cliffs ; about one hundred
feet thick.

5. Clay, shale, thin beds of sand-
stone ; lignite, and silicified wood.

6. Sand-rock, without concretions ;
dividing naturally into rhomboidal
masses; numerous veins of argil-
laceous iron ore and of clay, ap-
proaching to pipe- clay at the lower
part.

7. Dark coloured shale, with round-
ish masses of sand-rock, and several
layers of rich ironstone, thin layers
of lignite, and innumerable frag-
ments of carbonized vegetables.

HAT

[212]

H E L

HA'TCHETINE. A variety of bitumen,
known also as mineral adipocere,
found in the iron ore of Merthyr
Tydvil in Glamorganshire. It is
insoluble in water, but soluble in
alcohol and ether. It fuses at
160°. It is of the hardness of soft
tallow.

HATTSMA'JSTNITE. } Pyramidal manga-

HAUSSMA'NNITE. ) nese-ore. The
Manganese oxyde* hydrate* of Haiiy.
It occurs in porphyry, in veins, in
America and Germany. It is of a
brownish -black colour. It consists,
according to Turner, of 98-10 of
red oxide of maganese, silica 0-34,
oxygen 0'21, baryta O'll, water
0-43.

HATIYNE. Dodecahedral Zeolite, or
Lapis Lazuli.

HEA'VY SPAE. Sulphate of barytes,
baroselenite, or prismatic heavy
spar. The Baryte sulphatee of
Haiiy ; the Schwer spath of Wer-
ner; and Prismatischer halbaryte
of Mohs. There are several varie-
ties of this genus, namely, the
compact heavy spar, having a
splintery and uneven fracture ; the
fibrous heavy spar ; the straight
and curved lamellar heavy spar;
the radiated heavy spar ; the fetid
heavy spar, giving out, on friction
a hepatic odour, whence it is also
called hepatite ; the earthy heavy
spar ; the prismatic heavy spar.

Heavy spar consists of baryta 66
parts and sulphuric acid 34 parts.
It frequently contains a trace of
silex, alumine, oxide of iron, and
sometimes of sulphate of strontian.
It occurs in veins, both massive
and crystallized, in many parts of
England, Ireland, Scotland, and
Germany, being found in primary,
transition, and secondary rocks. It
is of different colours. It strongly
decrepitates when heated, and fuses
into a white enamel, which in the
course of some hours falls into pow-
der. One of the most striking
characters of this mineral is its

great specific gravity, which varies
from 4-29 to 4-50. It is from this
circumstance it has obtained its
name. It is harder than crystal-
lized carbonate of lime, but may be
scratched by fluate of lime. Heavy
spar may be confounded with sul-
phate of strontian, but its specific
gravity is greater. After fusion,
the enamel produced from heavy
spar, if applied to the tongue, pro-
duces a taste similar to that of
rotten eggs, this does not occur in
the enamel of sulphate of strontian.

HEDENBER'GITE. An earthy mineral
so named after Hedenberg, who
first analysed it ; it is a variety of
hornblende, and is found near
Tunaberg, in Sweden.

HE'LICAL. (Mice, Fr. eV£ Gr.)
Spiral ; winding.

HE'LIOLITES. A genus of fossils
found in the Silurian rocks.

HE'LIANTHOIDA. Just as we may see
the Helianthoida and Ascidioida of
our seas fixed to their boulders and
rocky skerries. — Hugh Miller.

HE'LIOTBOPE. (heliotrope,^? eliotropia,
It. heliotropium, Lat.
Gr. from ^Xtos and

1 . A plant, the turnsole.

2. Heliotrop of Werner. Quartz-
agathe vert obscur et ponctue of
Haiiy. Called also Blood-stone. A
variety of rhombohedral quartz, of
a deep green colour, with dissemi-
nated spots of yellow and red jasper.
It is more or less translucent, in
which respect it differs from jasper.
It occurs massive. By some min-
eralogists it is supposed to be cal-
cedony, coloured by chlorite or
green earth. Fracture imperfectly
conchoidal. Specific gravity about
2 -63. It consists of silica with
about seven per cent, of alumina
and five per cent, of iron. It is
infusible before the blow-pipe.
The finest specimens are brought
from Siberia and Bucharia. Like
agate, it is employed in forming

H E L

[213 ]

HEP

ornamental articles, and is much
esteemed.
HE'LIX. (e\tg, Gr.) PI. Helices.

1. The outer bar, or margin, of the
external ear.

2. The snail. A globular or orbi-
cular shell ; spire short, convex or
conoidal, last whorl ventricose;
opening entire, being wider than
long ; no operculum. The helix
aspera, or common snail, is a well-
known illustration. Parkinson ob-
serves of the fossil helix, " Shells
of this genus are rarely found in a
state of petrifaction. The circum-
stances of conservation in which
they are found are, generally, such
as are explicable on the supposition
of their having become involved in
the gradually accreting tufaceous
matter, which is deposited by cer-
tain streams and rivers ; or in the
stalactitic concretions forming in
the cavities of limestone rocks, of
comparatively modern formation."

3. A screw, a spiral.
HELMI'NTHOLITE. The name given to

what have been considered fossil
impressions of earth-worms.

HELMINTHO'IDA. The name given to
the second sub-kingdom of the ani-
mal kingdom, called also Diplo-
neura. This sub-kingdom compre-
hends the classes Polygastrica, Eo-
tifera, Suctoria, Cirrhopoda, and
Annelida.

HE'LVINE. Tetrahedral garnet.

HEMI'PTERA. (from ty/ui and wrepov,
Gr. So called, because their wing-
covers at the base are of a substance
resembling horn or leather, and at
the tip are membranous.) The
eighth order of the class Insecta.
These insects have four wings,
either stretched straight out, or
resting across each other ; the su-
perior are coriaceous at their base,
with a membranous apex. The
mouth of hemipterous insects is
adapted for extracting fluids by
suction only.

HEMISPHERE, (hemisphere, Fr. emzs-

f&ro, It. hemispharium, Lat. rjfua-
(fiaipiov, Gr.) The half of a globe
when it is supposed to be cut
through its centre, in the plane of
one of its greatest circles ; one-half
of the globe, or sphere, when
divided into two by a plane passing
through its centre. The equator
divides the sphere into two equal
parts, called the northern and south-
ern hemispheres. The horizon also
divides the sphere into two parts,
the upper and lower hemispheres.

HENDE'CAGON. (from evfteica, and ^oWa,
Gr.) A figure of eleven faces or
angles.

HEPA'TIC. } (hepaticus, Lat. Jiepati-

HEPA'TICAL. j que, Fr. epdtico, It.)
Belonging to the liver ; pertaining
to the liver; resembling liver in
form or colour.

HEPA'TIC CINNABAR. A dark- coloured,
steel-grey variety of the mercure
sulphure of Haiiy, or cinnabar.

HEPA'TIC^:. The first order of plants
in the class Anogens, comprising
the liver- worts.

HEPA'TIC PYRI'TES. Hepatic sulphuret
of iron. A variety of prismatic
iron-pyrites, of a yellow colour,
which, on exposure to the atmos-
phere, acquires a brown tarnish.
This embraces those varieties of
sulphuret of iron, which are sus-
ceptible of a peculiar decomposition,
by which the sulphur is more or
less disengaged. During this pro-
cess the pyrites is converted, wholly
or in part, into a compact oxide of
iron of a liver- brown colour, from
which circumstance it obtains its
name. The decomposition begins
at the surface, and gradually passes
into the centre.

HE'PATITE. A mineral ; a variety of
heavy spar, or sulphate of barytes.
This variety is distinguished by
its emitting a fetid smell when
rubbed, resembling that of sulphu-
retted hydrogen, arising from its
containing a portion of sulphur.

HE'PATULE. A name given by Kirwan

HEP

[214]

HEP

to certain combinations, called by
others hydrosulphurets.

HEPTACA'PSULAE. (from eWa, Gr. and
capsula, Lat.) Having seven cells.

HE'PTAGON. (heptagone et eptagone,
Er. ettagono, It. eVra and <yaWa,
Gr.) A figure having seven sides
and as many angles.

HEEBA'CEOUS. (herlaceus^at.} Plants
that perish annually down to the
roots, having succulent stems or
stalks. Of herbaceous plants, some
are annual, these perish, stem and
root, every year; some are biennial,
the roots subsisting two years ;
others are perennial, being perpe-
tuated for many years by their
roots, a new stem springing up
every year.

HEEMA'PHEODITE. (from "E/j/wjs, Mer-
cury, and 'A0/)o£/T?y, Yenus, h&rma-
phodite, Er. ermaphrodito, It. A
fabulous name, compounded of those
of Mercury and Yenus, Hermes and
Aphrodite.)

1 . Having both the male and female
parts of generation.

2. In botany, plants are so called
which contain both stamens and
ovarium, in centra-distinction to
monoecious and dioecious plants.

HEEMETIC SEAL, (from Hermes, the
reputed inventor of chemistry.)
When the neck of a glass vessel
or tube is heated to the melting
point and then twisted with pincers
till it become air-tight, the vessel
or tube is said to be hermetically
sealed, or to have received the
seal of Hermes.

HEEPETO'LOGY. (cpTre-ros and Xo'ryoe,
Gr.) That branch of natural his-
tory which treats of reptiles, their
habits, &c.

HE'ESCHELITE. A mineral of a white
colour, found by Herschel in oiivine,
and named after its discoverer.

HETEEOCEECAL. Professor Jukes says,
Eish have two forms of tail, the
one homocercal, that is in which the
caudal fin is equally spread round
the termination of the vertebral

column, as in the cod, perch, &c. ;
and the other heterocercal, where
the vertebral column is, as it were,
continued into the upper lobe of
the caudal fin, the extremity of the
body in reality being slightly bent
up, as in the dog-fish, shark, and
sturgeon. It is a very remarkable
fact, that in all fish, whether osse-
ous or cartilaginous, found in the
rocks more ancient than the lias,
the tails are heterocercal, while in
the lias and more recent rocks, the
majority of fish have homocercal tails.

HETERO'CLITAL. In conchology, re-
versed; a term applied to shells
whose spires turn in a contrary
direction to the usual way ; sinis-
tral. In shells, the axis of revolu-
tion is termed the columella, and
the turns of the spiral are denomi-
nated whorls. In consequence of
the situation of the heart and great
blood-vessels relatively to the shell,
the left side, or the mantle, is more
active than the right side, so that
the lateral turns are made in the
contrary direction. Sometimes, in
consequence of the heart being
placed on the right side the turns
of the spiral are made to the left :
this left-handed convolution seldom
occurs among the shells of land or
fresh-water mollusca.

HETEEO'POEA. The name given by
De Elainville to a genus of corals.
A species established by Mr. Lons-
dale, and by him named H. crassa,
found ia the Wenlock limestone,
is thus described in Sir E. Murchi-
son's Silurian System ; " branched,
the branches thick, tubes small,
radiating from a centre ; transverse
fracture; concentric layers formed
of two systems of tubes, one visible
to the naked eye, the other micro-
scopic, numerous and close together.

HETEEO'STEOPHE. (erepoaTpofai, Gr.
ex credos et ff^po(prj.} A term
applied to reversed shells, or shells
whose spires turn in a contrary
direction to the usual way ; sinis-

H E U

[215 J

H I

tral shells. Synonymous with
Heterocrital.

HETJ'LANDITE. Hemi-prismatic zeo-
lite, or foliated zeolite. A min-
eral thus named after Heuland.
It occurs in drusy cavities, in
secondary trap rocks, in the Hartz
mountains, in Ireland, and in
Scotland. It is of different
colours, white, grey, brown, and
red. Its constituent parts are
silica 59, alumina 16*87, potash 8,
(or, according to others, lime 9,)
water 16 '5. Specific gravity 2 '20.
Hardness 3*5 to 4. It commonly
is found crystallised in right oblique
angled prisms (two of its opposed
lateral planes being longer than the
other two) generally modified on
the angles and one lateral edge. It
also occurs massive, frequently in a
globular form, and is easily frangible.

HE'XAGON. (hexagone, Pr. esdgono,
It. egd^wvos, Gr. from ef six,
and 7wi//o, angle.) A figure of six
sides or angles ; the most capacious
of all the figures that can be added
to each other without any interstice.
The cells of the honeycomb are
hexagons.

HE'XAGYN. (from e£, six, and ^vvrj
Gr. a woman.) A plant having six
pistils.

HEXAGT'ETAN". Having six pistils.

HEXAHE'DRAL. Having six sides
equal to one another ; cubal.

HEXAHE'DRON. (from e£ and efya, Gr.
hexaedre, Fr. esaedra, It.) A cube;
a solid body having six equal faces.

HEXA'NDEB. (from e'£, six, and avrjp,
Gr. a man.) As plants which have
six pistils are denominated hexa-
gyns, so those with six stamens are
termed hexanders.

HEX'ANDRIAN. Having six stamens ;
belonging to the sixth class in
Linnaeus' s sexual method.

HEXA'NGULAR. from eg and angulus.}
Having six angles.

HE'XAPED. } e|fo7ro'&7<?, (from ejf and

HE'XAPOD. ) Trofo, Gr.) An animal
with six feet.

HEXAPE'TALOUS. (from ef, six, and
7reTa\ov, Gr. a leaf.) A plant
having six petals; a corolla con-
sisting of six petals.

HEXAPHY'LLOTJS. (from ejf and 0v\Xoi/,
Gr.) Six -leaved.

HIG'HTEA. The name assigned by
Mr. Bowerbank to a genus of fossil
fruits found in the London clay,
and thus named in honour of an
able botanist, John Hight, Esq.
The following is Mr. Bowerbank' s
description, "pericarp one celled,
valveless. Placenta central, usually
five, rarely four, or six angled, ob-
conical and very large, with one or
more seeds attached to each angle.
Seeds and placenta enveloped in a
mass of downy or filamentous
structure, which fills up the whole
of the remaining space within the
pericarp. Seed about two or three
times its own diameter in length,
angular and somewhat curved.
Testa reticulated. Ten species
have been distinguished by Mr.
Bowerbank, and are beautifully
figured in his " History of the
Fossil Pruits of the London Clay."

HI'LTTM. (Mum, Lat.) In botany,
the small mark on seeds showing
the spot where they were joined to
the fruit.

HINGE. In conchology, the point by
which bivalve shells are united : it
is formed by the teeth of the one
valve inserting themselves between
those of the other, or by the teeth
of one valve fitting into the cavities
or sockets of the opposite valve.

It is on the peculiar construction
of the hinge that the generic
character of bivalve shells is mainly
founded, in connection with the
general form of the shell. Some
hinges have no visible teeth, and
are termed inarticulate ; hinges with
few teeth are termed articulate;
those having many teeth are called
multiarticulale.

HINNI'TES. A genus of eared ir-
regular bivalves, separated from

HIP

[216]

HOG

tho pectens by the irregularity of
surface. Several species are known
in the Jurassic, cretaceous, and
tertiary deposits. — Lycett.

HlPPOPO'TAMUS. (iTrTroTrorafios, Gr.

hippopotame, Fr. ippopotamo, It.)
Bochart conceived this animal to
be the Behemoth of the book of
Job. One existing species only is
at present known, but Cuvier con-
sidered he had discovered four in
thfe fossil state. The first so nearly
resembles the species now existing
that the Baron could at first
scarcely distinguish them. The
second is about the size of the
wild boar; the third was inter-
mediate between the two, and the
fourth about the size of a guinea-
pig. The hippopotamus, or river-
horse, belongs to the order Pachy-
dermata, or thick-skinned animals,
class Mammalia. This genus of
quadrupeds has four fore-teeth in
the upper jaw, disposed in pairs at
a distance from each other ; and
four prominent fore-teeth in the
under jaw, the intermediate ones
being longest. There are two
tusks in each jaw, those of the
under being long, and obliquely
truncated; in both they stand
solitary, and are recurvated. No
other animal has tusks formed
like the hippopotamus. Those of
the elephant are larger, but neither
angular nor striated ; those of the
morse are very much striated
towards the root, but not angular ;
the tusk of the narwhal is straight,
but twisted spirally by the stria3 of
the surface. In the hippopotamus
there are five striaB, concentrical to
the contour of the tooth. The feet
are hoofed on the edges. The head
is of an enormous size, and the
mouth vastly wide. The ears are
small and pointed. The eyes and
nostrils are small. The body is
naked. The tail is about a foot
long, taper, compressed and naked.
The legs are short and thick ; the

belly reaching to the ground. One
species only is known, the hippopo-
tamus amphibius, confined to the
rivers of Africa.

Fossil bones and teeth of the
hippopotamus are abundantly found
in England, France, Germany, and
Italy ; several extinct species have
been determined by Cuvier. The
head of a hippopotamus was found
in Lancashire, under the peat;
bones and teeth are found in large
quantities in the Yal d'Arno, in
Italy, and in alluvial deposites in
the neighbourhood of Home.

HI'PPOPUS. (from fWo?, a horse, and
7ro£9, a foot.) A subtransverse,
equivalve, inequilateral shell; lu-
nule closed with crenulated edges ;
the hinge formed of two long com-
pressed entering teeth in one valve,
and three in the other ; the crescent
closed. Parkinson states that he
does not know of any fossil shells
of this genus having been found,
but Sowerby mentions fossil species.

HIPPOTHE'RIUM. (from ITTTTO?, and
Orjpiov, Gr.) An extinct animal,
allied to the horse, belonging to
the miocene period.

HIPPOPO'DITJM. A fossil genus of
thick, inequilateral, equivalve, bi-
valve shells; the hinge is much
incrassated, with one rugged ob-
lique tooth, One species H. pond-
erosum, is found in the lower lias.
— Lycett.

HI'PPUBITE. A fossil conical shell,
having an under shell of great
depth, with a flat lid or operculum.
This genus is believed to be wholly
extinct. The operculum is some-
times convex, but generally it is
concave. The particular economy
of the inhabitant of this shell is
not known. Lamarck has placed
the hippurite among his chambered
cephalopoda.

HISI'NGEBITE. A mineral of a dark
colour, occurrring massive, found
in the cavities of calcareous spar.

HOG- TOOTH SPAS. A dodecahedral

H 0 L

[ 217 ]

H 0 K

variety of calcareous spar. The
Matastatique of Haiiy.
HOLOPTY'CHIUS. A genus of fossil
fishes, discovered in the old
red sandstone formation. The
name has been assigned to ichthyo-
lites of this genus by M. Agassiz
from the folds of the scales. A
species has been named H. Nobilis-
simus, in honour of the Eev. James
Noble, who discovered a splendid
specimen, measuring two feet four
inches by twelve inches, in the old
red sandstone at Clashbinnie, in
Scotland.

"The generic characters," says
M. Agassiz, "consist in the peculiar
structure of the scales, the enamel-
led surface of which is marked by
large undulating furrows. Another
characteristic feature is in the dis-
tant position of the ventral fins, far
removed towards the tail, and much
nearer the arms and anal fins than
in any other genus of the family of
ganoids." — Murchison's Silurian

The Holoptychius is the most
characteristic and most abundant
ichthyolite of the upper old red
sandstone. Agassiz states that the
Holoptychius of the coal measures
is the largest of all osseous fishes.
— Hugh Miller.

HOLOTHT/BIA. A zoophyte belonging
to the order Pedicellata, class
Echinodermata. The holothuria is
covered with a thick coriaceous
skin, which, by means of longitu-
dinal and circular bands of muscu-
lar fibres, the animal can shorten
or lengthen at pleasure. The body
is oblong, and open at each end;
numerous tentacula surround the
mouth. There are many species.

HO'LMITE. A mineral, a variety of
carbonate of lime, named after Mr.
Holme, who analysed it. Its con-
stituents are lime, carbonic acid,
oxide of iron, silica, alumina, and
water.

HOMACA'NTHUS. A genus of ichthyo-

lites of the old red sandstone, one
species of which, H. Arcuatus, has
been described by Agassiz.

HO'MALONOTUS. The name assigned
by Mr. Konig to a genus of trilo-
bites, in which the longitudinal
division into lobes is scarcely per-
ceptible. Four species have been
described, namely, H. Knightii,
H. Ludensis, H. Delphinocephalus,
and H. Herschelii. These are all
found in the Upper Silurian rocks.

HO'MOCERCAL. See Heterocercd.

HOMOGENEITY. (homogtneite, Fr.
omogeneitd, It.) Of the same
nature; having the same nature
throughout.

HOMOGE'NEAL. } (ojioyevrjs, Gr. homo-

HOMOGE'NEOFS. j gene, Fr. omogeneo,
It. ) Similitude of kind ; sameness
of nature.

HOMO'LOGOUS. (homologue, Fr. omologoy
It. 6,110X0709, Gr.) Having the
same manner or proportions.

HOMOTHO'RAX. A genus of fossil
fishes of the old red sandstone.

HONE, (hcen, Sax.) Whetstone slate.
A variety of talcy slate, containing
particles of quartz : when these
particles are exceedingly minute,
and the slate possesses a certain,
degree of hardness with a uniform
consistence, it yields hones of the
best quality. Kirwan gave to this
mineral the name novaculite, from
novacula, the Latin for a razor.

HO'NEY- STONE. Pyramidal mellite.
The Honigstein of Werner ; Mellite
of Haiiy and Erongniart ; and
Mellilite of Kirwan. It is pyra-
midal, its primitive form being a
pyramid of 118° 4' and 93° 22'.
It was first discovered in Thuringia,
between the layers of wood-coal.
It is of a honey-yellow colour,
sometimes a little tinged with
brown. Transparency considerable.
When heated it whitens, and in
the open air burns without being
sensibly charred. It yields neither
flame, smoke, nor odour. It is

HOB,

[ 218 ]

HOE

composed of alumina, water, and
an acid to which Klaproth gave
the name of mellitic acid : the
latter constitutes 46 per cent, of
the whole. It differs from amber
in its weak electricity, double re-
fraction, and chemical character.
HO'ENBLENDE. The amphibole of
Haiiy. A mineral of a black or
dark green colour, often inter-
mixed : heavier than either quartz
or felspar, but less hard, its specific
gravity being between 3-15 to 3 -38.
It enters largely into the composi-
tion, and forms a constituent part
of several of the trap rocks, and
appears to connect the primary
with the volcanic. "When breathed
on, it yields a peculiarly bitter
smell. Before the blow-pipe it
melts easily into a black or grayish-
black, glass. There are many va-
rieties of hornblende, known as ear-
inthine, tremolite, actynolite, cala-
mite, amianthus, &c. &c. The
constituents of hornblende are, sil-
ica 45 '60, magnesia 18-50, lime
14, alumina 1-18, protoxide of
iron 71 50, fluoric acid 1'50. Mas-
sive hornblende is generally coarse-
ly granular and lamellar; when
intermixed with felspar in large
lamellar grains, it forms sienite.
This very common mineral may,
generally, be easily recognised.
Though sometimes in regular and
distinct crystals, it is more com-
monly the result of a confused
crystallization, and appears in mas-
ses composed of Iamina3, acicular
crystals, or fibres variously aggrega-
ted. Though inferior to schorl in
hardness, hornblende usually will
scratch glass, and, though with
difficulty, will yield sparks with
steel. Its laminated structure, its
inferior hardness, and its inability
of becoming electric by heat, dis-
tinguish it from schorl. It is less
hard and more easily fusible than
augite. It differs from epidote in
hardness, and the results of fusion.

Its powder is not soft to the touch
like that of asbestus.
So' BE BLENDE SCHIST. One of the
metamorphic rocks, composed prin-
cipally of hornblende, with an un-
certain proportion of felspar, and
sometimes grains of quartz : its
colour is usually black. Dr.
M'Culloch observes, " hornblende
schist may at first have been mere
clay, for clay or shale is found
changed by trap into Lydian stone,
a substance differing from horn-
blende schist almost solely in its
compactness and in the uniformity
of its texture. Argillaceous schist,
when in contact with granite, is
sometimes converted into horn-
blende schist, the schist becoming
first siliceous, and, at the contact,
hornblende schist."
HOENE'EA. The name given by
Lamouroux to a genus of fossil
corals. One species, found in the
"Wenlock limestone, has been named
by Mr. Lonsdale, H. crassa, and is
by that gentleman thus described,
"Branches short, thick, flat, dicho-
tomosed; opening of the cells large,
elevated, and irregularly disposed
on one side ; opposite side striated ;
internal structure not ascertained. "
H'OENSTONE. The silex corne of
Brongniart; the quartz agathe
grossier of Haiiy; Hornstein of
Werner. Prof. Jameson divides
Hornstone into three sub-species,
namely, Splintery Hornstone, Con-
choidal Hornstone, and Woodstone.
A siliceous mineral ; a sub-species
of quartz. It has usually a dull
and splintery fracture, but some
times it is conchoidal. In appear-
ance it closely resembles compact
felspar, but it differs from felspar
in being infusible without the addi-
tion of an alkali ; it occurs massive,
and in extraneous external shapes;
lustre dull or glimmering, opaque
or translucent on the edges ; some-
times the whole mass, if thin, has
the strong translucency of certain

HOE

[219]

H Y A

horns. According to Kirwan, its
constituents are, silica 72, alumina
22, carbonate of lime 6. "A speci-
men yielded to Faraday," says
Phillips, "silica 71 '3, alumina
15-3, protoxide of iron 9*3, and a
trace of lime." Its colours are
numerous, and commonly dull. Its
infusibility by the blow-pipe dis-
tinguishes it from petrosilex and
jade. Its translucency serves to
render it distinct from jasper. It
is generally more dull than flint,
and emits sparks more feebly with
steel. It is deficient in lustre in
comparison with quartz.

HO'RXSTONE PORPHYRY. The Horn-
stein porphir of Werner. A variety
of porphyry of a red, brown, pur-
ple or blackish colour. Fracture
splintery and conchoidal. Emits
sparks when struck with steel. Is
susceptible of a fine polish.

HO'RSTED SAND. (So called from Hor-
sted in Sussex.) The Horsted sand
forms one of the members of the
Hastings beds, or central group of
the Wealden formation. It con-
sists of grey, white, fawn coloured,
and ferruginous sands and friable
sandstone, with numerous small
portions of lignite. It has been
found principally in Sussex and
Kent The Horsted sand is char-
acterized by the dissemination
throughout of small portions of
lignite, which appear to have orig-
inated from the carbonization of
plants of the fern tribe. — Mantell.

HO'RTUS SICCTJS. (Lat.) A collection
of dried plants.

HU'MBOLDITE. A rare mineral, thus
named after Humboldt.

HU'MITE. A reddish-brown mineral,
found at Somma, thus named after
Sir A. Hume.

HY'ACINTH. (vaKtvOos, Gr. hyacintfatt,
Lat. hyacinthe, Fr.) The Hiazinth
of Werner; Zircon hyacinthe of
Brongniart. A variety of pyra-
midal zircon, of a hyacinth-red

colour; it occurs also, but more
rarely, of a yellow, grey, and green
colour, and sometimes, though very
rarely, it is found white. It is
crystallized, and when in distinct
crystals its ordinary form is a four-
sided rectangular prism, terminated
by four rhombic planes. Each
plane angle at the summit is 73°
44'. It is found in beds of streams
and rivers along with rubies, sap-
phires, &c., but sometimes it occurs
in the primary rocks. It consists
of, zirconia 70, silica 25, oxide of
iron 0-5. It is considered a gem,
but is little used as such. The
finest specimens are brought from
Ceylon, but it is found in Europe in
many places. It is cut by the
jewellers, like the diamond, into
rose and table forms, and possessing,
as it does, though in an inferior
degree, the play of the diamond it
is frequently sold for that more
precious gem.

HY ACI'NTHINE. A mineral of a brown
or greenish colour, usually crys-
tallized in rectangular eight-sided
prisms. Fracture imperfectly con-
choidal. Transparent. Causes
double refraction.

HYAL^'A. (So named from its semi-
transparent shell.) The Hyalaa
has the appearance of a bivalve
with soldered valves, the upper one
being the largest ; this difference
of size of the seeming valves causes
an aperture through which the
animal sends forth two large yellow
and violet wings, or sails, rounded
and divided at their summit into
three lobes. When its wings, or
sails, are unfolded, it moves with
great velocity on the surface of the
sea. The Pteropods, both from the
beautiful colouring of their filmy
wings, and from their number and
symmetry, are better entitled to
the appellation of the butterflies of
the ocean, than the escalop shells,
which have sometimes been so
called.— .Zfrv. W. Kirby.

H Y A

[ 220 ]

H Y D

HY' ALINE, (from hyalus, Lat. va\os,
Gr.) Transparent.

HY'ALITE. (m\os, Gr.) The Hya-
lith of Werner ; quartz hyalin eon-
cretionne of Haiiy. A yellowish
or greyish variety of uncleavable
quartz or opal. It exhibits the
usual appearance of a concretion,
and differs but little from calcedony,
except in possessing a vitreous
lustre, and sometimes a loose tex-
ture. It is found in secondary trap
rocks; it occurs in grains, fila-
ments, and botryoidal masses. It
is infusible before the blow-pipe.
It is nearly all silica, its component
parts being silica 92-00, water 6'33.
Specific gravity from 2-4 to 2'11.

HYBER'NACLE. | (hilernacula, Lat.) 1.

HIBEB/NACLE. ) The winter dwell-
ing or residence of animals.
2. In botany that part of the plant
which defends the embryo from in-
juries arising from frost.

HY'BODONT. (from £/3o§, Gr. and
dens, Lat.) A sub-family of sharks,
according to the arrangement of M.
Agassiz. They seem to have be-
gun with the coal formation, to
have continued throughout the
oolitic deposition, and to have
ceased at the beginning of the chalk
formation. The teeth of this sub-
family possess characters interme-
diate between the blunt crushing
teeth of cestracionts, and the sharp
cutting teeth of squaloids.

HYB'ODUS. A genus of fishes that
prevailed throughout the oolitic
period. Not a single genus of all
that are found in the oolitic series
exist at the present time.

HY'BRID. (vfipis, Gr. hylrida, Lat.
hydride, Fr.) Mongrel ; a term ap-
plied both to plants and animals,
when of a cross-breed.

HTDA'TID. (v£a™<?, Gr. hydatide, Fr.)
An order of internal worms. In
hydatids there has not been discov-
ered any vascular system. Hyda-
tids, so frequently found in the
liver and other parts of the body in

mammalia, have been considered
by some as animals, consisting
merely of a stomach ; by others, as
a matrix, or womb, from something
like young hydatids being frequent-
ly found adhering to their inner
side. Hydatids immersed in warm
water, immediately after being ob-
tained from a living animal, are
observed to have a contractile
power, but they have no external
opening ; they are pellucid spheri-
cal bodies, of different sizes and
kinds. Each consists of two coats,
the inner of which is extremely
delicate. They do not possess any
visible blood-vessels, though the
sac containing them has abundance
of vessels, nerves, &c., derived from
those of the organ with which it is
connected. Hydatids ought not to
be confounded with watery vesicles,
connected occasionally with the
kidney, &c., which are not enclosed
in cysts, have no small hydatids
adhering to their inner surface, and
want contractility. There are many
genera.

HYDNOPHO'RA. The name given by
M. Fischer to a genus of stony
polypifers, fixed, aud incrusting
other bodies ; either forming a sub-
globose, gibbons, or located mass,
or spread in subfoliaceous lobes ;
the upper surface is set with small
stars raised in pyramids. The stars
project and are conical ; the central
axis is solid, simple, or dilated,
surrounded by radiating adhering
lamellaa. Many species, both re-
cent and fossil, have been described.
Lamarck formed the genus monti-
cularia for their reception.

HY'DBATE. (from vdwp, water, Gr.)
A chemical compound in definite
proportions of a solid body with
water, still retaining a solid form.
It must, however, be borne in mind
that when water in combination
with other bodies contributes (as
in crystailized bodies) to their reg-
ular form and transparency, it is

H Y D

[221 ]

H Y D

then termed water of crystallization.
The hydrates are numerous, as hy-
drates of alumine, baryta, cobalt,
copper, lime, magnesia, potassa,
soda, &c., &c. 2. Any uncrystal-
lized substance which contains
water in a fixed definite proportion.
HYDRAU'LIC \ (vdpavXis, Gr. hy~
HYDRAU'LICAL. > draulicus, Lat. hy-
HYDRAU/LICK. ) draulique, Fr. idrau-
lico, It.) Relating to the convey-
ance of water through pipes. The
siphuncle of the nautilus, ammon-
ite, belemnite, &c., forms a very
beautiful and complete hydraulic
apparatus.

HY'DRAULICS. The science of the
motion of fluids, and the construc-
tion of all kinds of instruments and
machines relating thereto.
HY'DRO. As a prefix, denotes that
hydrogen enters into the composi-
tion of the substance which it sig-
nifies.

HY'DROGEN. (from vSwp and ryeiWw,
Gr.) One of the simple, or ele-
mentary bodies. Inflammable air,
proved by Cavendish to be the
basis of water, from which circum-
stance it has obtained its name. It
is obtained by the action of iron or
zinc on dilute sulphuric acid. Hy-
drogen is colourless, and has com-
monly a slight odour of garlic ; it
is not absorbable by water ; it is
devoid of taste, and is destructive
of life when respired for any time.
It is the lightest body known, 100
cubic inches weighing only 2.25
grains, or being nearly thirteen
times lighter than atmospheric air.
It is combustible, and, when pure,
burns with a yellowish-white
flame. Hydrogen enters into the
composition of all waters, and is
evolved in a compound state from
volcanos, from certain fissures in
the earth, and in districts where
coal is found. Two volumes of
hydrogen unite with one of oxygen
in the production of water. As
far as the superficies of our planet

is concerned, water so predomi-
nates, that, at first sight, hydrogen
might be considered as constituting
a substance of more relative abund-
ance than it really does. The
quantity of hydrogen locked up in
coal is considerable. According to
Dr. Thomson, cannal coal contains
21 per cent, of it, although in the
Newcastle caking coal the propor-
tion is but a trifle more then 4 per
cent. Hydrogen may be considered
as the most important substance of
its class next to oxygen, which
enters into the composition of the
earth* s crust. Symbol H.

HYDRO' GENATED. Combined with hy-
drogen.

HYDRO'GENOUS. (from uftwp. water,
and <yevvdiv, to produce, Gr.) Pro-
duced by the action of water, as
hydrogenous rocks or strata. Among
the older rocks, as among the newer,
two entirely distinct classes occur,
namely, pyrogenous and hydrogenous
deposits.

HYDRO'GRAPHY. (from vScop and
<y/>a0o>, Gr. idrogrqfia, It. hgdro-
graphie, Fr.) Description of the
watery part of the globe ; the art
of measuring and describing the
sea, rivers, canals, lakes, &c. With
regard to the sea, it gives an ac-
count of its tides, counter-tides,
soundings, bays, gulfs, creeks, &c.,
as also of the rocks, shelves, sands,
shallows, promontories, harbours;
the distance and bearing of one
point from another; with every
thing that is remarkable either at
sea or on the coast.

HYDRO'IDA. The second order of the
class Hydrozoa, comprising the
medusa, hydra, &c.

HYDRO'METER. (from v&wp and pA7pov,
Gr. hydrometre, Fr. idrometro, It.)
An instrument for measuring the
extent or depth, gravity, density,
and velocity of liquids.

HY'DROPHANE. (from v8wp and (fiaivw,
Gr.) Called also changeable opal.
Silex Hydrophaue of Brongniart.

H Y D

[ 222 ]

Quartz resinite hydrophane of
Haiiy. A variety of opal which is
opaque and white when dry, but
by immersion in water becomes
transparent. Hydrophanes, or
changeable opals, are highly prized
by collectors. In order, however,
to preserve their beauty, care must
be taken never to immerse them in
any but pure water, and to remove
them from the fluid as soon as they
have acquired their transparency;
otherwise, their pores will soon
become filled with earthy particles,
and their hydrophanous properties
destroyed. "Hydrophane has a
porous structure, and when im-
mersed in water bubbles of air
escape from its pores, while the
water enters, and its weight is in-
creased. When the pores are thus
filled with water, a less portion of
the light is reflected during its
passage through the mineral, than
if the same pores were filled with
air; consequently more light is
transmitted, and the transparency
increased." — Cleaveland.

HYDBO'PHANOTJS. Those substances
are termed hydrophanous which,
when dry, are opaque, but become
transparent on being wetted. This
property especially occurs in some
varieties of common and semi-opal.

HY'DROPHYTE. (from vdiap and 0vrov,
Gr.) A plant which lives and
grows in water. Sir C. Lyell
observes, "the number of hydro-
phytes is very considerable, and
their stations more varied than
could have been anticipated; for
while some plants are covered and
uncovered daily with the tide,
others live in abysses of the ocean,
at the extraordinary depth of one
thousand feet : and although in
such situations there must reign
darkness more profound than night,
at leasA to our organs, many of
these vegetables are highly co-
loured."— Principles of Geology,

HYDBOST'ATICS. (from v£wp and

E Y M

Gr. hydrostatique, Fr.
idrostatica, It.) The science which
treats of the nature, gravity, pres-
sure, and equilibrium of fluids, and
of the weighing of solids in them.

HY'DBIJBET. A compound of hydrogen
with a metal.

HYDBOZ'OA. The second class of the
sub-kingdom Coelenterata, compri-
sing two orders, namely, Lucenna-
roida and Hydroida.

HYGRO'METEB. (from v^pos and /lerpov,
Gr. hygrometre, Fr. igrometro, It.)
An instrument for measuring the
degree of moisture of the atmos-
phere. There are various kinds of
hygrometers; for whatever either
swells by moisture, or shrinks by
dryness, is capable of being formed
into an hygrometer.

HYL^EosAu'Etrs. (from vK^, wood,
weald, or forest, and aavpos, a
lizard, Gr., the Forest Lizard.) A
fossil lizard discovered in the weal-
den formation of Tilgate forest by
Dr. Mantell, in 1832. Its pro-
bable length was about twenty-five
feet. It is characterised by a series
of long, flat, and pointed bones,
which appear to have formed a
large dermal fringe, resembling the
bones on the back of the modern
iguana. In this reptile the osteo-
logy of the lizard seems blended
with that of the crocodile.

HYMENO'PTEBA. (from v/aevdTnepos,
Gr. alas membranaceas habens :
membrane-winged.) The first or-
der of the class Insecta, comprising
the Ichneumon, Saw-fly, &c. It
is divided into six families. They
have four membranous wings, and
the tail of the female is usually
armed with a sting. Though the
insects of this order are included in
the mandibulate section, for their
mouth is furnished with mandibles
and maxillae, yet they do not ge-
nerally use them to masticate their
food, but for purposes usually con-
nected with their sequence of in-
stincts, as the bees in building their

HYP

[ 223 ]

fl Y S

cells ; the wasps in scraping parti-
cles of wood from posts and rails
for a similar purpose, and likewise
to seize their prey; but the great
instrument by which they collect
their food is their tongue ; this the
bees particularly have the power
of inflating, and can wipe with it
both convex and concave surfaces ;
and with it they lick, but not suck,
the honey from the blossoms, for
Keamur has proved that this organ
acts as a tongue, and not as a
pump.

HYPANTHOCEINI'TES. (from VTTO, under,
av6o<$, a flower, and Kplvov, a lily.)
A genus of encrinites belonging to
the Silurian system, and established
by Phillips. The name of this
genus is taken from the floriform
aspect of the basal portion of the
body. In this new genus, says
Prof. Phillips, the lowest plates
clearly seen appear to correspond
to the first costals of the genus
Actinocrinites. One species only
is described, namely, H. decorus,
which is described and figured in
Sir. E. Murchison's Silurian Sys-
tem.

HY'PERSTHENE. \ (from virep; above,

HY'PEESTENE. ) and <r0evos, strength,
Gr., in allusion to its difficult re-
frangibility.) Prismatoidal Schil-
ler-spar. Labrador Schiller-spar.
A mineral of a greenish-black co-
lour, but on the cleavage of a
copper-red. Occurs in granular
and lamellar concretions, and mas-
sive. It is found in Labrador, in
the Isle of Skye, in Banffshire, and
in the Shetland Isles. It is com-
posed of silica, magnesia, alumina,
lime, and oxide of iron, the last of
which is said to form one-fourth of
the whole.

HYPOCRATE'BIFOBM. Salver-shaped ;
a term applied to a monopetalous
corolla, the limb of which being

placed on a tube, spreads out hori-
zontally.

HYPOGA'STBIC. (from v-a-o and <yaffvrjp,
Gr.) Belonging to that region of
the abdomen which is called the
hypogastrium.

HYPOGA'STRITJM. The lower anterior
region of the abdomen, from a
little below the umbilicus, or navel,
to the pubes.

HY'POGENE. (from VTTO, under, and
ftvofjuu, to be born, Gr.) A term
applied to rocks, expressing that
they have assumed their form or
structure, at a depth from the
surface.

Sir C. Lyell, who proposes to
give this term to certain rocks,
observes, "It will appear that the
popular nomenclature of geology,
in reference to the so called * pri-
mary' rocks, is not only imperfect,
but in a great degree founded on a
false theory; inasmuch as some
granites and granitic schists are of
origin posterior to many secondary
rocks. In other words, some pri-
mary formations can already be
shown to be newer than many
secondary groups, a manifest con-
tradiction in terms." To obviate
this difficulty, Sir C. Lyell prefers
the term hypogene, as one not of
chronological import, but implying
the theory that such rocks are
netherforraed, and have not as-
sumed their form and structure at
the surface.

HY'BACOTHERE. } An extinct genus

HYEACOTHE'BIUM. ) of pachydermal
mammalians, remains of which have
been found in the London clay.
Two species, H. Cuniculus, and
H. Leporinum have been described
by Prof. Owen. The nearest exist-
ing ally to the Hyracothere is now
peculiar to America.

HY'STEIX. (&TT/M& Gr.) The por-
cupine.

J A D

[224]

JAN

IJ

JA'DE. The Nephrit of Werner;
Nephrite of Jameson ; called also
nephritic stone, nephrite, and axe-
stone. It was formerly much cele-
brated for its supposed medicinal
properties in nephritic affections,
or diseases of the kidneys. It is
found in Hungary and Siberia,
America, Egypt, and China. The
inhabitants of New Zealand form
it into axes, and other cutting in-
struments, from which circumstance
it has obtained the name of axe-
stone. Its surface is smooth;
fracture splintery. It has a greasy
feel. Colour, dark leek green. In
hardness, jade is, at least, equal to
quartz ; it possesses a peculiar te-
nacity, which renders it difficult
either to break, cut, or polish.
Brochant states its fresh fracture
to present a paler green than that
of its surface. Before the blow-
pipe it fuses easily, and with a
slight ebullition, into a bead of
white semi-transparent glass. Its
analysis is very variously given by
different authors; its constituents
are, according to some, silica, carbo-
nate of magnesia, alumina, and car-
bonate of lime; others add chrome,
oxide of manganese, soda, and po-
tassa. In consequence of its tena-
city, it has been wrought into
chains and other delicate works.

JAMB. A term used by miners for a
thick bed of stone which pre-
vents their pursuing a vein.

JA'MESONITE. A mineral, thus named
after Prof. Jameson, by Haidinger;
axotomous antimony-glance. It
was first discovered in Cornwall,
in clay- si ate, and it has since been
found in Germany and Siberia.
Its colour is steel-grey. It con-
sists of lead, antimony, sulphur,
and iron.

JANTHINE. | (from ianthwn, Lat. a
JA'NTHINA. j violet.) The violet
snail. A purple-coloured univalve
shell, nearly resembling a snail in
its form : it is recent, and com-
monly found in the Mediterranean.
The inhabitant of this shell is said,
when irritated, to discharge a pur-
ple secretion. The Janthina was
considered a helix until the time of
Lamarck, who placed it in a distinct
genus. He ascertained that the
inhabitant of this shell differed es-
sentially from the snail. The organ
which, in the snail, would consti-
tute a foot, is, in the janthina,
formed for swimming, not for
crawling.

JA'NTHINA PEAGILIS. A species of
janthina. Sir C. Lyell remarks,
"janthina fragilis has wandered
into almost every sea, both tropical
and temperate. This common
oceanic shell derives its buoyancy
from an admirably contrived float,
which has enabled it not only to
disperse itself so universally, but
to become an active agent in dis-
seminating other species, which
attach themselves, or their ova, to
its shell. — Principles of Geology.

According to the account given
by Bosc, the janthina exhibits many
remarkable peculiarities. When
the sea is calm, these animals may
be seen collected often in large
bands, swimming over the surface
by means of a floating apparatus
consisting of aerial vesicles pro-
duced by their foot. During this
action their head is very prominent,
and the foot or line of vesicles forms
an angle with the middle of the
shell. When the sea is rough, the
animal absorbs the air from its
vesicles, changes the direction of
its foot, contracts its body, and lets

J A 8

[ 225

ICE

itself sink. It does the same when
in danger from any enemy, and
like the cuttle-fish, has the power
of emitting a coloured fluid, which,
by darkening the surrounding
water, serves to conceal it from
view. If the floating apparatus
be injured or destroyed, there exists
a reproductive power in the foot,
by which it can be restored.

JA'KGON. (jargon, Fr.) The zircon
jargon of Brongniart. A mineral, a
variety of zircon: This variety or
sub-species of zircon is of a grey,
brown, or yellow colour, and is
met with in small transparent or
translucent prismatic crystals. It
is obtained principally from Ceylon:
according to the analysis of Vau-
quelin, it consists of zirconia 66 '0,
silica 31'0, oxide of iron 2'0.

JA'SPEE. (jaspe, Fr. pierre dure et
opaque, de la nature de V agate;
jaspide, It.) "Mineralogists have
not been able," says Prof. Jameson,
" to ascertain the origin of the word
Jasper. We only know that it is
of high authority, because it occurs
in the Hebrew and Greek langu-
ages. We are also ignorant of the
particular stone denominated Jasper
by the ancients." A species or
variety of rhombohedral quartz.
It is an ingredient in the compo-
sition of many mountains. It
occurs usually in large amorphous
masses, and sometimes also crystal-
lized in six-sided prisms. Fracture
conchoidal. It is said to compose
the substance of entire ranges of
the Asiatic mountains. When
quartz is combined with a consid-
erable proportion of iron and alum-
ine, it loses its translucency and
becomes jasper. There are many
varieties of jasper, distinguished
principally by their different col-
ours, and the arrangement of those
colours.

Chemically, jasper differs from
agate solely in containing a larger
portion of iron ; mineralogically, it

may be distinguished by its opaci-
ty. Some mineralogists divide jas-
per into five sub-species, namely,
Egyptian jasper, striped jasper,
porcelain jasper, common jasper,
and agate jasper. Jasper is com-
monly somewhat less hard than
flint, or even common quartz, it
will, however, give fire with steel.
It is entirely opaque, or, some-
times, feebly translucent at the
edges ; it presents almost every
variety of colour. Specific gravity
from 2-30 to 2- 70. It is infusible
before the blow-pipe, but loses its
colours. With the compound blow-
pipe, Professor Silliman says, it
fuses into a greyish-black slag with
white spots. Jasper is often tra-
versed by metallic veins, or by
veins of quartz. It sometimes
contains fossil shells and marine
plants. It is never, says Professor
Cleaveland, porphyritic: the base
of that, which has been called jas-
per porphyry, is fusible, and is
either petrosilex or compact felspar.
By some it has been supposed that
jasper has been formed by the fil-
tration of silex into beds of ferru-
ginous clay.

JA'SPER OPAL. The Opal Jaspis of
Werner. A sub-species of opal of
different shades of red, brown, and
yellow, the colour being often dis-
tributed in spotted, veined, or
clouded delineations. It occurs
massive only, and is found in Sax-
ony, Hungary, Turkey, and Siberia.
Before the blow-pipe it is infusible.
Lustre shining, between vitreous
and resinous. Fracture conchoidal.
Specific gravity from 1-89 to 2'08.
According to Klaproth it consists
of silica 43-5, oxide of iron 47*0,
water 7 '5.

ICE'BEKG. (from ice and lerg, Germ.)
A large mass of ice, met with in
cold regions, floating upon the sea,
sometimes of an enormous magni-
tude and great height. Icebergs
have been seen of the great height

a G

ICE

[226 ]

I C H

t)f 300 feet, and as it has been as-
certained that for every foot above
the surface of the sea- water there
are eight feet below, the whole
thickness must be immense. In a
geological point of view, icebergs
are to be viewed as very important
and powerful agents, inasmuch as
they are the means of transporting
to great distances, animals, plants,
and rocks.

ICE- SPAR. So named from its resem-
blance to ice. A mineral occurring
both massive and in flat crystals.
It is found at Mount Somma, near
Naples.

ICHTHY'ODON. The name used by some
authors to designate a tooth of any
fossil fish.

ICHTHYODO'EULITE. The fossil dorsal
spine of certain fishes, armed with
tooth-like hooks, or prickles. These
were long supposed, says Professor
Buckland, to be jaws, and true
teeth; more recently they have
been ascertained to be dorsal spines
of fishes, and, from their supposed
defensive office, have been named
ichthyodorulites , from the Greek
words txOvs, a fish, Sdpv, a spear,
and X/0os, a stone. The icthyodo-
rulites of the old red sandstone,
observes M. Agassiz, belong to
distinct species of the genera oncTius
and ctenacanthus. These bony
spines are more or less arched, and
grooved by longitudinal furrows,
separated by round ridges forming
ribs. The great distinction between
this genus of Ichthyodorulites, and
the large species of Hybodus of the
lias and new sandstone, to which
they have some resemblance in the
arrangement of their longitudinal
furrows, is, that their posterior
edge has no sharp points or teeth,
while in the genus hylodus there
are on that side strong points which
are arched downwards. — Murchison.
That highly talented, and much
to be lamented author, the late
Hugh Miller, says, " there occa-

sionally turn up, in the sandstones
of Perthshire, ichthyodorulites that
in bulk and appearance resemble
the teeth of a harrow, rounded at
the edges by a few months wear."

I'CHTHYOLITE. (from ixOvs, and \iOos,
Gr. ichtyolite, Fr.) The name given
to any fossil fish ; a petrified fish.
Fossil fishes occur in all the Eng-
lish formations, from the old red
sandstone to the tertiary deposits
inclusive.

ICHTHYOLI'TIC. Pertaining to fossil
fishes, as the ichthyolitic formation.
" In the ichthyolitic formation, im-
mediately over the Silurian, that
of the old red sandstone, the ganoids
first appear." — Hugh Miller.

ICHTHYO'LOGY. (from IxQvs, a ^sn*
and Xo<yo?, Gr. discourse; ichtyo-
logie, Fr. ictologia, It.) That
branch of zoology which treats of
the structure, classification, habits,
and history of fishes. The study
of fossil ichthyology, says Prof.
Buckland, is of peculiar importance
to the geologist, as it enables him
to follow an entire class of animals,
of so high a division as the verte-
brate, through the whole series of
geological formations; and to in-
stitute comparisons between their
various conditions during successive
periods of the earth's formation.
Professor Agassiz has already ex-
tended the number of fossil fishes
to two hundred genera, and eight
hundred and fifty species. No ex-
isting genus is found among the
fossil fishes of any stratum older
than the chalk formation.

ICHTHYO'PHAGOUS. (from /X^S, & fish,

and 0afyo>, Gr. to eat ; ichthyophage,
Fr. colui che non si ciba d'altro
fuorchb di pesci, It.) Feeding on
fish.

ICHTHYOSATJR. ] (fl'Om «X^S» a ^8D>
ICHTHYOSAURUS. ) and ffavpos, Gr.

a lizard.) A fish-like lizard; an
immense fossil marine- saurian or
reptile, having an intermediate
organization between that of a

I C H

[227]

I C H

lizard and a fish. The name ap-
pears to have been given to it by
M. Konig. The genus comprises
many species ; some of these attain
a magnitude not inferior to that of
young whales. The head of the
ichthyosaurus resembled that of a
dolphin, its teeth were conical,
sharp, and striated, and exceeding-
ly numerous, in some cases amount-
ing to nearly two hundred, not
enclosed in separate sockets, but,
as in the crocodile, ranged in one
continuous groove, or furrow, of
the maxillary bone ; as also in the
crocodile, abundant provision was
made for replacing the old teeth,
as they were lost, -by a supply of
new ones. The eye was of enor-
mous magnitude, the orbit in some
instances measuring fourteen inches
in its longer diameter, and Prof.
Buckland states, " We have evi-
dence that it possessed both micro-
scopic and telescopic properties.
The bony sclerotic of the ichthyo-
saurus approaches to the form of
the bony circle in the eye of the
Golden Eagle ; one of its uses being
to vary the sphere of distinct
vision, in order to descry their prey
at long or short distances. The
soft parts of the eyes of the ichthy-
osaurus have, of course, entirely
perished; but the preservation of
this curiously constructed hoop of
bony plates, shows that the enor-
mous eye, of which they formed
the front, was an optical instrument
of varied and prodigious power,
making this marine saurian to
descry its prey at great or little
distances, in the darkness of night
and in the ocean's depths." The
beak was that of che porpoise ; the
teeth, as before mentioned, those
of the crocodile. In order to de-
monstrate the close relation between
the ichthyosaurus and the lacerta
family, it is desirable to state, that
the lower jaw in that family, in-
stead of having, like other quadru-

peds, a single bone on either side,
exhibits not fewer than six of these ;
one called the dental, which carries
the teeth, forms the whole anterior
extremity of the jaw, and continues
to cover the upper portion, and to
lap over the exterior; the rest of
the outer face is formed, in the
posterior part by a second bone,
the coronoid ; the bottom by a
third, the angular ; and the inner
face by a fourth, the opercular : in
addition to these four bones, the
articular, which is placed at the
posterior extremity for the purpose
which its name denotes, and a small
crescent-shaped bone, which some-
times forms the coronoid process,
complete the stated number. Of
these bones, the five first have been
proved to have been possessed by
the Ichthyosaurus, occupying situ-
ations closely corresponding to
those which they possess in the
crocodile. The crescent- shaped
bone is the only one of the series
not yet detected. The vertebrae
nearly resembled those of the shark,
being hour-glass shaped, and hav-
ing both faces of their body deeply
concave as in fishes ; the vertebral
column was composed of more than
one hundred pieces ; the ribs were
slender, and the majority of them
bifurcated, or forked, at the top;
the bones of the sternum were
strong and largely developed, and
combined nearly in the same man-
ner as in the ornithorynchus or
platypus. The ichthyosaurus had
four paddles, the form of its ex-
tremities deviating from the sau-
rians and approaching the mam-
malians, being converted from feet
into fins; these fins, or paddles,
were composed of numerous bones
enclosed in one fold of integument ;
the fore-paddle was composed of
nearly one hundred bones, and like
the mammalians it possessed a hu-
merua, or shoulder bone, a radius
and ulna, or the bones of the fore

I C H

[ 228 ]

I C I

arm, and phalanges; the bones of
the phalanges were polygonal and
exceedingly numerous, as before
stated. The hind-paddles were
Tery much smaller, containing only
from thirty to forty bones. The
general conformation of the ichthy-
osaurus must have greatly resem-
bled that of the porpoise or grampus.
Its teeth would have sufficiently
proved it to have been carnivorous,
but the subsequent discovery of its
faBcal remains, now called copro-
lites, and the finding within the
intestinal canal the half-digested
remains of fishes and reptiles, ren-
der this point quite certain ; like
the crocodile, it must have gorged
its prey entire ; its stomach was
exceedingly capacious, forming a
sort of pouch, or sac, and extending
through nearly the whole body.
The fossil remains of the ichthyo-
saurus have been most abundantly
discovered in the lias formation,
and it appears to have become ex-
tinct at the termination of the
secondary series of geological for-
mations : the debris of ichthyosauri
have been found more abundantly
in England than in any other
country, and they are to be met
with in every formation from the
new red sandstone up to the green
sand inclusive. It is however, the
opinion of Bakewell that the ich-
thyosaurus, or some species of a
similar genus, is still existing in
the present seas, and with his re-
marks the description of the fish-
like lizard will be concluded.
" About sixteen years since, a large
animal was seen for several sum-
mers in the Atlantic, near the coast
of the United States, and was called
the great sea-serpent. I am in-
formed by Professor Silliman, that
many persons who attested the ex-
istence of the sea serpent from their
own observations, were so highly
respectable, both for intelligence
and veracity, that their evidence

could not be disputed. I remember
one of the most particular descrip-
tions of the sea-serpent was given
by an American captain, who saw
the animal raise a large portion of
its body from the water : he rep-
resented it as of great length, and
about the bulk of a large water
cask ; it had paddles somewhat like
a turtle, and enormous jaws like
the crocodile. This description
certainly approaches to, or may be
said to correspond with, the ich-
thyosaurus, of which animal the
captain had probably never heard."
— Bakewell, Cony bear e, De la,
Heche.

ICHTHYOPHTHA'LMITE. (from *x^s>
and o00a\/io9, Gr.) Fish-eye stone;
apophyllite ; pyramidal zeolite ; the
fischaugenstein of Werner; meso-
type epointee of Haiiy. It is of a
white colour, and semi-transparent,
or translucent. Occurs both crys-
tallised and massive. The primitive
form of its crystals is a four-sided
prism, with rectangular bases. It
is easily divisible by percussion
into Iamina3, whose broader surfaces
are splendent and somewhat pearly.
It scarcely scratches glass, and does
not yield sparks when struck with
steel. Specific gravity 2 -46. Before
the blow-pipe it exfoliates, froths,
and eventually melts into an
opaque bead. It is composed of
silica, 50, lime 23, potash 4,
water 18, with a trace of fluoric
acid. It is found in secondary
trap-rocks in the Hebrides and
other parts of Scotland, in Sweden,
and Iceland.

ICHTHYOSPON'DYLE. The name given
by many writers on oryctology to
signify a vertebra of different
species of fossil fishes.

Pcius. The termination of adjectives in
icius and aceous express a resemb-
lance to a material; those in eus and
ous indicates the material itself: thus,
membranaceous, resembling skin ;
membranous, skin itself: cori-

ICO

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JEW

aceous, leathery ; latericious, re-
sembling bricks.

ICOSAHE'DRAL. (from icosahedron.)
Having twenty equal sides or faces.

ICOSAHE'BRON. (elicoffdcdpos, Gr. ico-
sedre, Pr. isosaedro, It.) A regular
solid, consisting of twenty triangu-
lar pyramids, whose vertices meet
in the centre of a sphere supposed
to circumscribe it; and therefore
have their height and bases equal :
wherefore the solidity of one of
these pyramids multiplied by
twenty, the number of bases, gives
the solid contents of the icosahedron.

ICOSA'KDRIAN. (from ei'icoai and avijp,
Gr.) The twelfth class in Linnaeus' s
sexual method, consisting of plants
with hermaphrodite flowers, fur-
nished with twenty or more sta-
mens, inserted into the calyx. The
first order of this class consists of
trees bearing for the most part
stone fruits, surrounded by a pulp,
as the plum, peach, cherry, &c. ;
in the second order we find the
apple, pear, &c. ; in the third
order, the genus rosae. In this
class the stamens grow out of the
sides of the calyx, as in the straw-
berry, and it is important to ob-
serve, that such a mode of insertion
indicates the wholesomeness of the
fruit ; we are not aware that there
is a single exception to this rule,
so that a traveller, who might
meet with an unknown fruit, need
not scruple to eat it if he find the
stamens thus inserted. This cha-
racter of the insertion of the sta-
mens into the calyx holds good in
other classes, as well as in the
class Icosandria ; thus, in the genus
Ribes, including the gooseberry
and currant, which belong to the
class Pentandria, the stamens grow
out of the calyx, and these fruits
are well known to be wholesome,
while many of the berries of the
same class, whose stamens have
not a like insertion, are often yery
deleterious.

FDOCRASE. (from Idea, form, and
icpaffis, mixture, Gr.) The term
idocrase was given to this mineral
by Haiiy in reference to its form,
•which is a mixed figure. Idocrase
is a silicate of lime, combined with
a silicate of alumina. A mineral
found in lava, and formerly mis-
taken for the hyacinth; it is the
Yesuvian of Werner. See Vesuvian.

JE'FFERSONITE. A mineral found in
New Jersey; colour olive-green,
passing into brown. It is named
after Mr. President Jefferson.

JET. (from Gaga, a river of Asia;
jayet, Fr.) The Jayet of Haiiy;
Lignite Jayet of Brongniart ; Pech
Kohle of Werner. A mineral sub-
stance, found in detached kidney-
formed masses in many countries.
It is of a firm and very even struc-
ture, harder than asphaltum, and
susceptible of a good polish. It
becomes electrical by rubbing, at-
tracting light bodies, like amber.
In many respects it resembles can-
nel-coal, its colour is full-black,
and it does not soil the fingers.
It is, however, easily distinguished
from cannel-coal, in being specifi-
cally lighter than water, which
cannel-coal is not, and in possess-
ing electrical properties which can-
nel-coal does not. Some persons
have supposed that jet is a true
amber, differing only in the mere
circumstance of colour. During
combustion it emits a bituminous
smell. It is never found in strata
or continued masses, but always in
separate and unconnected heaps.

It is formed into various trinkets,
and is particularly used for making
mourning ornaments, such as ear-
rings, brooches, bracelets, buttons &c.

JEWS-STONE.

1. An extraneous fossil, being the
elevated spine of a very large egg-
shaped sea-urchin, or echinus.

2. A local term for basalt. In
Salop and Worcestershire this name
is applied to any hard trap-rock.

I'GNEOFS BOCKS. Those rocks are
termed igneous which are con-
sidered to have once been in a
fluid state from the action of heat
upon them, and in that state to
have overflowed, to have been in-
jected among, or to have been pro-
pelled through, other rocks.

IGUA'NA. A species of lizard, a native
of many parts of America and the
"West Indies, rarely met with any
where north or south of the tropics.
It is from three to five feet long,
from the end of the snout to the
tip of the tail. It inhabits rocky
and woody places, and feeds on
insects and vegetables. Cuvier
states that the iguana subsists upon
fruit, grain, and leaves : Eosc, that
it lives principally upon insects.
It nestles in hollow rocks and trees.
The female lays its eggs, which
have a thin skin like those of the
turtle, and are about the size of
those of a pigeon, in the sand.
Though not amphibious, they are
said to be able to remain under
water an hour. When they swim,
they do not use their feet, but place
them close to their body, and guide
themselves with their tails. Capt.
Belcher found, in the Island of
Isabella, swarms of iguanas, that
appeared omnivorous. This state-
ment proves both Cuvier and Bosc
to be correct. The .teeth of the
iguana are not fitted for comminu-
ting its food, and it is said to
swallow it whole.

IGTTA'NODON. An extinct fossil colossal
lizard, discovered in the strata of
Tilgate Forest by that indefatigable
historian of the chalk and Wealden
formation, the late Dr. Mantell.
He observes, " the discovery of the
teeth and other remains of a non-
descript herbivorous reptile in the
strata of Tilgate Forest, a reptile
pronounced by Cuvier to be 'encore
plus extraordinaire quo tous ceux
dont nous avons connoissance,' is
one of the most gratifying results

[ 230 ] I G U

of my labours." The remains of
one of these immense animals have
lately been found in the Kentish
rag, near Maidstone. The Kentish
rag is a grey arenaceous limestone,
belonging to the Shanklin sands.
From the great resemblance in the
dentature, as well as in many other
extraordinary characteristics, of this
immense reptile to that of the igu-
ana, Dr. Mantell determined Jon
naming it the Iguanodon, signify-
ing an animal having teeth like
the iguana. In the perfect teeth,
and in those which have been but
little worn, the crown is somewhat
of a prismatic form; widest, and
most depressed, in front; convex
posteriorly, and rather flattened at
the sides. As soon as the tooth
emerges from the gum it gradually
enlarges, and its edges approach
each other and terminate in a
point, making the upper part of the
crown angular ; the edges forming
the side of this angle are deeply
serrated, or dentated ; and the
teeth exhibit two kinds of pro-
visions to maintain sharp edges
along the cutting surface : the first
the serrated edge already described;
the second, a provision of compen-
sation for the gradual destruction
of this edge, by substituting a plate
of thin enamel, to maintain a cut-
ting power in the anterior portion
of the tooth, until its entire sub-
stance was consumed. These teeth
were sometimes two inches and a
half in length. While the crown
of the tooth was diminishing above,
an absorption of the fang was
proceeding below, caused by the
pressure of a new tooth rising to
replace the old one, until by con-
tinual consumption, both above and
below, the middle portion of the
older tooth was reduced to a hollow
stump, which fell from the jaw to
make room for its more efficient
successor. The size attained by
the iguanodon appears to have been

ILL

[231 ]

I N D

enormous, the average length from
the snout to the tip of the tail
being estimated by Dr. Mantell at
seventy feet, while, he considers,
some may have been one hundred
feet in length. This last calcula-
tion Prof. Buckland deems impro-
bable, but he gives a length of
seventy feet to the iguanodon. A
thigh-bone in the possession of Dr.
Mantell is three feet eight inches
long, and thirty- five inches round,
at its largest extremity. The length
of the hind foot is supposed to have
been six feet and a-half ; the cir-
cumference of the body, fourteen
feet and a-half. A most remark-
able appendage possessed by the
iguanodon was a horn of bone,
placed upon the nose, equal in size,
and resembling in form, the lesser
horn of the rhinoceros ; here was a
further analogy between the extinct
fossil iguanodon and the recent
iguana. The base of this nasal
horn was of an irregular oval form,
and slightly concave. It possessed
an osseous structure, and appears to
have had no internal cavity. It is
evident that it was not attached to
the skull by a bony union, as are
the horns of the mammalia.

ILLJG'NTJS. A genus of trilobites thus
named by Dalman. One species,
Illaeuus perovalis, so named by Sir
R. Murchison, is described by him
as found in the Lower Silurian
rocks. It is of an elongated oval
form ; the central lobe of the body
slightly prolonged into the caudal
portion.

I'MBRICATED. (Mricatus,'L'dt.) Laid
one over the other at the edges, like
the tiles of a house. In botany,
applied to leaves when so placed.

IMPE'EMEABLE. Not admitting the
passage of fluids through its pores
or interstices, as clay or marl,
which are impermeable to water.

I'NCTDENCE. (from in, upon, and cado,
to fall, Lat.) The direction in
which one body falls on or strikes

another : the angle which the mov-
ing body makes with the plane of
the body struck is called the angle
of incidence.

INCI'SOR. (from incisor es, Lat.) A
fore or cutting tooth.

INCRUSTA'TION. (incrustatio, Lat. in-
crustation, Fr. incrostatbra, It.)
An adherent covering ; something
superinduced; a coating of siliceous
matter.

INDECI'DUOTTS. (from in and deciduus,
Lat.) Not falling off; not shed,
as the leaves of trees, but evergreen.

I'NDiANrrE. A whitish or grey
mineral, brought from the Carnatic,
found in masses, of a foliated
structure, and having a shining
lustre.

I'NDICOLITE. (from indigo , and \i'0os,
Gr.) An indigo-coloured mineral
found in Sweden. It occurs crys-
tallised, and is considered a variety
of shorl.

INDIGENOUS. (indigena, Lat. indi-
gene, Fr.) Native to a country ;
originally born, or produced, in a
particular country. The term is
more usually applied to plants than
animals ; thus plants, the natural
produce of any particular country,
are said to be indigenous to that
country.

INDU'CTION. (mductio, Lat. induction,
Fr. induzione, It.) A consequence
drawn from several propositions or
principles first laid down ; reason-
ing from particulars to generals, as
when from several particular pro-
positions we infer one general.
The process by which a new
principle is collected from an
assemblage of facts, has been
termed induction.

INDU'CTIVE REASONING. That kind
of philosophic reasoning which
ascends from particular facts to
general principles, and then de-
scends again from these general
principles to particular applications
and exemplifications.

INDT/SIA. (indmiat Lat.) The case

D

I 232 ]

D

or covering of certain larvae ; gene-
rally used plurally, mdmice.
INDU'SIAL LIMESTONE. A fresh -water
limestone to which the name in-
dusial has been given, from its
containing the indusiae, or cases,
of the larvse of Phrygania.
IN.EQUILA'TERAL. } Having unequal
INEQUILA'TERAL. ) sides ; in con-
chology, when the anterior and
posterior sides make different
angles with the hinge.
INE'QTJIVALVE. j Where one valve
INEOJJIVA'LVULAR. j is more convex
than the other, or dissimilar in any
respect, as in the common oyster.
INFLORESCENCE, (inflorescentia, Lat.)
A word used to express the par-
ticular manner in which flowers
are placed upon a plant ; this by
older writers was denominated the
modus florendi, or manner of
flowering. Botanists distinguish
many kinds of inflorescence, under
the name swhorl, cluster or raceme,
spike, corymb, fascicle, tuft, umbel,
cyme, panicle, bunch, &c.
INFUNDIBTJ'LIFORH. (from infundibu-
lum and forma, Lat.) Funnel-
shaped : in botany, applied to a
monopetalous corolla, having a
conical border placed upon a tube.
INFUSO'RIA. } Beings so

IMFT/SORY ANIMA'LTJLES. j extreme-
ly minute as to be invisible to the
naked eye, and which have only
been discovered since the invention
of the microscope. The infusoria
have been divided into two orders,
the Rotifera and Homogenea. The
order Rotifera comprises many
genera, Brachionus, Furcularia,
Tubicolaria, and Yaginicola : the
Homogenea comprises TJreolaria,
Trichoda, Leucophra, Kerona, Hi-
mantopes, &c., &c. The most
extraordinary genus of all is the
Proteus. It is not possible to
assign to them any determinate
form ; their figure changes momen-
tarily ; sometimes rounded, some-
times divided. The bodies of the

infusoria, are, for the most part,
gelatinous.

When we place a drop of any
infusion of animal or vegetable
matter under a powerful micro-
scope, and throw a light through
that drop, and through the micro-
scope to the eye, we discover in
the drop of water various forms of
living beings, some of a rounded,
some of a lengthened form, and
some exhibiting ramifications shoot-
ing in all directions, but all ap-
parently of a soft, transparent,
gelatinous, and almost homogeneous
texture. These beings constitute
the lowest form of animals with
which we are at present acquainted,
and they were at first considered asto-
matous, that is, without any mouth,
and agastric, or possessing no
stomach, and were called infusoria,
a denomination explanatory merely
of their habitat, but not of their
structure. Upon further exami-
nation, it was discovered that there
existed animalcule of a higher
denomination ; these exist in every
stagnant pool of water, in every
river, and in the ocean. Upon
examining with great care many
years since the effects of coloured
infusions upon these minute ani-
malculae, it was found that they
devoured great quantities of the
coloured matter in which they
were placed, and that they convey-
ed it into internal cavities or
stomachs, which are sometimes
extremely numerous in them.
Those cavities exist in almost every
known genus. Sometimes there
are nearly 200 stomachs in a single
animalcule. Animalcules are found
so exceedingly minute that nearly
five hundred millions are contained
in a single drop of water, that is,
as many as there are individuals of
our own race on the face of the
earth. In those minute beings
which constitute the simplest forms
of animals, there are numerous

INF

[ 233 ]

INS

stomachs, the lowest class is there-
fore called Polygastrica. They are
the food of higher classes, particu-
larly of zoophytes. There is no
proper skeleton in the entire class
of animalcules called Polygastrica.
Some of the polygastrica exude on
their surface a secretion which
agglutinates, and lays hold of,
foreign particles floating in the
waters which surround them, and
thus form for themselves a partial
covering. The earthy matter,
however, is not their own produce.
—Prof. Grant.

Prof. Buckland observes, "We
are more perplexed in attempting
to comprehend the organization of
the minutest infusoria, than that of
a whale ; and one of the last con-
clusions at which we arrive, is a
conviction that the greatest and
most important operations of nature
are conducted by the agency of
atoms too minute to be either
perceptible by the human eye, or
comprehensible by the human un-
derstanding."

Ehrenberg has ascertained that
the infusoria, which have heretofore
been considered as scarcely orga-
nized, have an internal structure
resembling that of the higher ani-
mals. He has discovered in them
muscles, intestines, teeth, different
kinds of glands, eyes, nerves, and
male and female organs of repro-
duction. He finds that some are
born alive, others produced by
eggs, and some multiplied by spon-
taneous divisions of their bodies
into two or more distinct animals.
Their powers of reproduction are
so great, that from one individual
a million were produced in ten
days ; on the eleventh day four
millions, and on the twelfth sixteen
millions. Ehrenberg has described
and figured more than 500 species
of animalcules; he has found
them in fog, in rain, and in
snow.

I'NGTJINAL. (from inguen, Lat.) Per-
taining to the groin.

INK-BAG. A bladder- shaped sac found
in some species of cephalopods,
containing a black and viscid fluid,
resembling ink, by ejecting which,
in case of danger from enemies,
they are enabled to render the sur-
rounding water opaque, and thus
to conceal themselves. Examples
of this contrivance may be seen in
the Sepia vulgaris and Loligo of
our seas. To the late Miss Mary
Anning we owe the discovery of
numerous fossil ink-bags, found in
the lias of Lyme Regis, still dis-
tended, as when they formed parts
of the living animals. The contents
of the ink-bags of cephalopods is
used in drawing, the sort preferred
is from an oriental species of sepia;
some of that extracted from a fossil
ink-bag found in the lias was used
by Sir Francis Chrantrey, on the
request of Dean Buckland, and was
by a celebrated painter, who was
ignorant of the particulars, pro-
nounced to be sepia of excellent
quality. This extreme indestruct-
ibleness of sepia arises from its
being chiefly composed of carbon.

INOCERA'MUS. A genus of fossil bi-
valvular shells of great range, ac-
cording to some authors, extending
from the Silurian to the chalk,
inclusive. Pictet refers the Ino-
ceramus of the Silurian and De-
vonian periods to Posidonomya.

INOSCULATION. "Dm°n ^J junction
of the extremities; the union, or
junction, of the mouths of vessels,
as arteries with veins.

I'NSECT. (insecta, Lat. insecte, Fr.
imitto, It.) The third class of
articulated animals provided with
articulated legs ; they possess a
dorsal vessel analogous to the ves-
tige of a heart, but are wholly
destitute of any branch for the
circulation. Insects breathe at-
mospheric air by means of tracheae,
which are most freely ramified

INS

[ 234]

INT

through all parts of the body;
they possess compound eyes. All
insects, which possess wings, me-
tamorphose, or pass through certain
changes, before they arrive at their
perfect form. In their first state,
after leaving the egg, they form
larvae, or caterpillars. The bodies
of insects are divided into head,
corslet, pectus, abdomen, and mem-
bers. The head is joined to the
body, in some, by ball and socket ;
in others, by plain surfaces ; in
others, after the manner of a hinge.
In some, the connection is entirely
ligamentous, the different motions
corresponding with the nature of
the joint. The corslet or thorax,
is situated between the pectus and
head. The first pair of feet are
joined to this, and it contains the
muscles for moving those and the
head. To the upper and lateral
part of the pectus, the wings, when
present, are fixed, and the four
posterior feet to its under part.
To the upper part a horny process
is frequently fixed, termed scutel-
lum, or escutcheon. The pectus
contains the muscles which move
the wings and four pair of the feet.
-Fyfe.

Cuvier divided insects into twelve
orders, but modern classification
places Insecta as the first class of
the sub-kingdom Annulosa, divi-
ding the class into nine orders.

INSECTI'VORA. (from insect and voro,
Lat.) In Cuvier's arrangement,
a family of animals which lead
a subterraneous life, and having
grinders studded with conical points.
They live principally on insects,
and many of them, in cold climates,
pass the winter season in a state of
torpidity. The hedgehog and mole
are examples.

IN SITU. A mineral is said to be
in situ, when in its natural place
or position.

I'NTEGRAL. (integral, Fr. integrate,
It. integer, Lat.) A portion of a

whole, being similar to the whole
and not an elementary portion.
Thus the smallest portion of car-
bonate of lime is still carbonate of
lime, but if by any means we
separate the carbonic acid from the
lime, we no longer have in these,
separately, integral portions but
the elementary parts.

INTERCO'STAL. (from inter and costa,
Lat. intercostal, Fr.) Anything
between the ribs, as the intercostal
muscles, intercostal arteries, nerves,
or veins.

INTERNO'DAL. (from inter and nodus,
Latin.) Applied to flower-stalks
proceeding from the intermediate
space of a branch between two
leaves.

I'JSTTERNODE. The space between one
knot or joint and another; a term
used both in conchology and botany.

INTERO'SSEAL. | (from inter and os,

INTERO'SSEOTJS. j Latin.) Placed
between bones, as interosseous
muscles, arteries, veins, &c.

INTERRUPTEDLY. In botany, applied
to compound leaves when the prin-
cipal leaflets are divided by intervals
of smaller ones; applied also to
spikes of flowers, when the larger
spikes are divided by a series of
smaller ones.

INTESTI'NA. Linnaeus divided the class
Vermes, or worms, into five orders,
the firstof whichhe named intestina;
these mostly inhabit the bodies of
other animals; they are denomi-
nated the most simple animals,
being perfectly naked, and without
limbs of any kind. Cuvier has
divided them into cavitaria, or
nematoidea, and parenchymata.
The cavitaria or nematoidea are
worms having cavities or stomachs,
or an intestinal canal floating in
a distinct abdominal cavity, such
canal extending from the mouth
to the anus. The parenchymata
comprises those species in which
the body is filled with a cellular
substance, or with a continuous

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235

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parenchyma ; the only alimentary
organ it contains being ramified
canals.

INTO'RSION. ) A twisting or turning

INTO'RTION. j in any particular di-
rection. A term used in botany
and conchology.

I'lnjuN. (from inula.} A vegetable
product, resembling starch, ob-
tained from the roots of the Inula
Hellenium, or elacampane, by
boiling them in water. It was
thus named by Mr. Rose.

INVE'RSION. (inversio, Lat.) Change
of order or position so that the
upper may be lower, or the lower
upper; the first last, or the last
first. In the order of superposition
of the different stratified rocks,
some strata may be wanting alto-
gether, but there will not be found
an inversion of the regular order
of superposition.

INVE'RTEBRAL. (from in and verte-
bral.) Not possessing any vertebral
column, or hard bony tube for the
spinal cord, or medulla spinalis;
not having a back-bone.

INVE'RTEBRATE. } All those animals

INVE'RTEBRATED. ) are invertebrated
which are included in the three
great divisions, mollusca, or cyclo-
gangliata; articulata, or diplo-
neura ; and radiata, or cyclo-neura.
The other great division includes
the vertebrata, or spini-cerebrata.
In the cephalopodes, the invertebrate
form of the lower divisions is
beginning to be lost, and the verte-
brate form of that division, to
which man belongs, to appear.
The first of the true vertebrated
animals, is the class of fishes ; from
this class upwards, including pisces,
amphibia, reptilia, aves, and mam-
malia, all are vertebrated. Prom
the class Pisces downwards, in-
cluding cephalopoda, pteropoda,
gasteropoda, conchiphera, tunicata,
of the division mollusca ; Crustacea,
arachnida, insecta, myriapoda, an-
nelida, cirrhopoda, rotifera, entozoa,

of the division articulata ; echino-
derma, acalepha, polypiphera, pori-
phera, polygastrica, of the division
radiata, all are invertebrated. There
is one remarkable distinction which
separates the vertebrated from the
invertebrated animals, namely,
that in the former, the muscles
have no external points of attach-
ment ; and in the latter, with a few
partial exceptions, no internal ones.

INVE'RTED. (from inverto, inversus,
Lat.) Turned upside down ;
turned inwards ; placed in contrary
order to that which was before, or
which is usual.

INVO'LTJCEL. A small or partial in-
volucre.

INVOLU'CRE. j (involucrum, Lat. cut

INVOLU'CRUM. } aliquid involvitur-)

1. Any membranous covering.

2. In botany, a species of calyx,
remote from the flower, and bearing
a great resemblance to bractese :
the involucre is composed of many
small leaves placed at the foot of
the general umbel ; in umbellifer-
ous plants, the involucre, accom-
panying the partial umbels, is
called the involucella.

INVOLU'CRET. A small, imperfect, or
partial involucre, an involucel.

INVOLUTE. |.(from involve, Lat.

INVOLUTED, j 1. In botany, applied
to leaves, when the margins are
rolled inwards upon each other.
2. In conchology, where the exte-
rior lip is turned inwards at the
margin, as in all the cyprese.

I'ODATE. A compound salt formed by
the combination of iodine, oxygen,
and a salifiable base ; as the iodates
of ammonia, soda, &c.

I'ODIDE. A compound of iodine and
some metallic substance ; as iodide
of iron, iodide of lead, &c. Also a
compound of iodine with a simple
non-metallic substance. When io-
dine combines with metals in more
than one proportion, it forms a
protiodide, or a periodide.

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PODIJT. I (from ioeifys, ex "ov, violet,
I'ODINE. j and eldos, appearance, Gr.)
This substance, which was discov-
ered by Courtois, a manufacturer
of salt-petre, at Paris, in 1812,
obtained its name from the colour
of its vapour, which is a beautiful
violet. Iodine is procured from
sea-water and from marine vegeta-
bles. It is of a greyish-black
colour and shining metallic lustre.
It is crystallizable ; the primitive
form of the crystals being a rhombic
octahedron. Iodine possesses an
extensive range of combination,
forming acids both with oxygen,
hydrogen, and chlorine. Iodine
forms one of the simple or element-
ary bodies, included in those that
are non-metallic.

POLITE, (from I'ov, violet, and X/flos,
a stone, Gr.) A stone of a violet
colour. The Prismatischer Quartz
of Mohs, the lolith of Werner, the
lolithe of Haiiy, the Dichroite of
Cordier, and the Cordierite of
Leonhard. It is found massive
and disseminated, and crystallized,
in Finland, Norway, Greenland,
Switzerland, and Spain ; in gneiss
and granite. It occurs in regular
six and twelve-sided prisms. Its
fracture is conchoidal and uneven.
It is of a deep blue colour when seen
along the axis, and of a brownish
yellow when seen in a direction
perpendicular to the axis of the
prism. When we look along the
resultant axes, which are inclined
62° 50' to one another, we see a
system of rings which are pretty
distinct when the plate is thin;
bnt when it is thick, and when the
plane passing through the axis is
in the plane of primitive polarisa-
tion, branches of blue and white
light are seen to diverge in the form
of a cross from the centre of the
system of rings. It consists of
silica, nearly 50 per cent., alumina,
mangnesia, oxide of iron, and oxide
of maganese. It was first brought

to France by Launoy, from Cape
de Gatte, in Spain. Specific
gravity 2'560. It scratches glass
easily, quartz with difficulty.

IEIDE'SCENE. (from iris, Lat. the
rainbow.) The quality of shining
with many colours, resembling
those of the rainbow.

IEIDE'SCENT. Shining with the col-
ours of the rainbow. Many mem-
branous shells exhibit on several
parts of their internal surface, a
glistening, silvery, or iridescent ap-
pearance. This appearance is caused
by the peculiar thinness, transpa-
rency, and regularity of arrange-
ment, of the outer layers of the
membrane, which, in conjunction
with the particles of carbonate of
lime, enter into the formation of
that part of the surface of the shell.
The surface, which has thus ac-
quired a pearly lustre, was formerly
believed to be a peculiar substance,
and was termed mother-of-pearl;
Sir David Brewster has, however,
satisfactorily proved in the Philo-
sophical Transactions, that the iride-
scent colours exhibited by these
surfaces are wholly the effect of
the parallel grooves, consequent
upon the regularity of arrangement
in the successive deposites of shells.

IEI'DIUM. (from iris, Lat.) An ex-
cessively infusible metal to which
this name has been given from some
of its salts having varied tints like
those of the rainbow, and from the
variety of colours exhibited by its
solution. It was discovered by Mr.
Tennant, in 1 803, who, in examin-
ing the black powder left after dis-
solving platina, found that it con-
tained two distinct metals, which
he named iridium and osmium. It
is of a pale steel-grey colour. It
occurs in grains, in alluvium, in
South, America. From the re-
searches of Berzelius, who estimates
the equivalent of Iridium at 98-8,
it appears to have three degrees of
oxidation ; and it is the rapid tran-

sition of these oxides into each
other, that occasions the variable
tints of iridium.

I'KIS. (iris, Lat. iris, Er. iride, It.
fas, Gr.)

1. The rainbow.

2. The membrane round the pupil
of the eye, deriving its name from
its various colours. The colour of
the iris corresponds in general with
that of the hair, being blue or
grey where the hair is light, and
brown or black where the hair and
complexion are of a dark colour.
It floats in the aqueous humour,
and serves to regulate the quantity
of light sent to the bottom of the
eye.

3. A genus of plants ; order
Monogynia, class Triandria ; the
flag-flower.

I'EISATED. A mineral is described as
irisated which exhibits the pris-
matic colours either externally or
internally ; the latter is generally
the consequence of some injury
sustained by the mineral.

IRON. One of the most generally
diffused of all solid minerals. Of
all the metals, the oxides of which
are neither alkalies nor earths, iron,
geologically considered, is the most
important. " Calculating the
mean," says De La Beche, " of
thirty kinds of rocks, and neglect-
ing iron ores, properly so called, of
every kind, iron constitutes, as an
oxide, 5 '5 of the lowest stratified
rocks, amounting to 14-72 per cent,
in mica slate with garnets, and
15-31 per cent, in chlorite slate.
It forms 12-62 per cent, in hypers-
thene rock, and about 20 per cent,
in basalts. Oxide of iron consti-
tutes about two or three per cent,
of the mass of granites and gneiss,
and between three and four per
cent, of the mass of greenstone and
the more common trappean rocks.
When we consider the large amount
of iron which exists either in the
state of an oxide, a carbonate, a

[ 237 ] I E 0

carburet, a silicate, or a sulphuret,
therein including all iron ores of
importance, we shall probably not
errr greatly if we estimate iron as
constituting about 2 per cent, of
the whole mineral crust of our
globe. There is scarcely a rock with-
out iron. — Geological Researches.

It is to the presence of iron that
rocks and stones most frequently
owe their colour, earths when pure
being white. The specific gravity
of all stones or earthy minerals if
it much exceed 2-5 may be at-
tributed to the presence of iron.

In its natural state iron is very
unlike what we are hourly accus-
tomed to see it. It presents itself
everywhere only as an earthy mass,
a dirty impure rust; and even
when found in the mine with a
metallic lustre, it is still far . from
possessing those qualities which
are necessary to fit it for the endless
uses to which it is applied. Man
has only to purify gold, silver, &c.
but he has, as it were, to create
iron. It does not appear to have
been known so early, or wrought
so easily, as gold, silver, and copper.
For its discovery we must have
recourse to the nations of the East.
The writings of Moses furnish us
with the most ample proof at how
early a period it was known in
Egypt and Phoenicia. He mentions
furnaces for working iron, "and
brought you out of the iron fur-
nace;" the ores from which iron
was extracted, " a land whose
stones are iron;" and he states
that swords, knives, axes, and tools
for cutting stones, were at that
time made of iron, "and if he
smite him with an instrument of
iron, so that he die, he is a mur-
derer," "and his hand fetcheth a
stroke with the axe to cut down
the tree," " thou shalt not lift up
any iron tool upon them." The
knowledge of iron was brought
over from Phrygia to Greece by

IRQ

[ 238 J

IRQ

the Dactyli, according to Hesiod,
as quoted by Pliny, who settled in
Crete during the reign of Minos I.
about 1431 years before Christ.
It would appear that a knowledge
of iron obtained even before the
deluge, for in Genesis we read
" And Zillah, she also bare Tubal-
Cain, an instructer of every artificer
in brass and iron."

Iron forms a constituent part of
many animal and vegetable sub-
stances ; it enters into the compo-
sition of the blood ; and the various
shades of hue of some of the most
delicate flowers are more or less
owing to its presence.

Iron is of a bluish-white colour,
and, when polished, has a consider-
able degree of brilliancy. It has
a styptic taste, and emits a smell
when rubbed. Its specific gravity
is 7-77.

Iron is placed the eighth in order,
as regards its malleability, possess-
ing this quality in a less degree
than gold, silver, copper, tin,
platinum, lead, and zinc. In duc-
tility it ranks fourth, being inferior
only to gold, silver, and platinum,
and it may be drawn out into wire
as fine as a human hair. In
tenacity it ranks first, iron one-
twelfth of an inch in diameter
being capable of supporting 995
pounds without breaking. Iron is
fusible at a temperature of 1797
Fahr. .

Iron is found native, and is then
generally considered to be of
meteoric origin, being alloyed with
nickel and other metals ; these
masses are called meteoric iron,
and it certainly appears that they
have fallen from the atmosphere.
A mass was discovered in Siberia
by Prof. Pallas, weighing 1680 Ibs.
A mass discovered in Bahia, in
Brazil, is estimated to weigh
14,000 Ibs.

A singular structure is frequently
observed in the argillaceous iron

ores of coal districts. The sub-
stance of the iron ore is formed
into conical sheaths, involving one
another, and marked by concentric
undulations aud radiating striae.
Large spheroidal masses of iron
ore, weighing at least a ton, are
thus found, in connexion with the
coal, at Ingleton, in Yorkshire;
and in the coal fields of Stafford-
shire and South "Wales, it is a well
known form of aggregation.

The quantity of iron manufac-
tured in Great Britain is enormous ;
in the year 1827 it was calculated
at 690,000 tons; nearly one-half
of which, or 296,000 tons, was
manufactured in Wales, and up-
wards of 200,000 in Staffordshire.
For the manufacturing of this
immense quantity, three millions
seven hundred and ninety-five thou-
sand tons of coals would be required.

In a supplementary note to
Professor Buckland's Bridge water
Treatise, it is stated, "Ehrenberg
has ascertained that a soft yellow
ochreous substance, Raseneisen,
which is found in large quantities
every spring in marshes about
Berlin, covering the bottom of
ditches, and in the footsteps of
animals, is composed of iron secre-
ted by infusorial animalcules of the
genus Gaillonella. This iron may
be separated from the siliceous
shields of these animals, which
retain their form after the ex-
traction of the iron.
I'BONSTONE. A heavy mineral, pos-
sessing sometimes a specific gravity
of 3*6, and composed chiefly of iron
combined with oxygen, carbonic
acid, silex, and water, with, in
some instances, calcareous earth.
When of a superior quality, it will
yield upwards of 36 per cent, of
iron. Mr. Bake well observes " We
know nothing certain, respecting
the formation of ironstone ; but it
appears to have been deposited in
fresh water, as it occurs in freeh-

I B 0

[ 239 ]

ISO

water strata in the regular coal
formation, and in the coal strata of
the oolites of Yorkshire, and
among the clay and sandstone
strata in the wealds of Kent. Few
geologists have attempted to ex-
plain the formation of ironstone.
The manufacture of iron was
formerly carried on to a consider-
able extent in the county of
Sussex ; Fuller in his "Worthies
observes, " it is almost incredible
how many great guns were made
of the iron of this county."

IRON FLINT. A mineral, thus named
by Jameson.

PEON-GLANCE. Rhombohedral iron-
ore. A peroxide of iron, of a dark
steel-gray colour. There are sev-
eral varieties ; the red varieties are
called red iron ore, and the fibrous,
hematite.

I'RON SAND. A variety of octohedral
iron-ore, in grains.

ISCHIA'TIC. (ischiadicus, Lat. ItrxiaSi-
/co9, Gr.) Pertaining to the ischium,
as the ischiatic notch, &c.

I'SCHIUM. (ischium, Lat. iffxl°v> ^rO
One of the bones of the pelvis,
situated in the lowest part thereof,
and being that bone upon which
we sit. It forms the under, and
largest portion of the acetabulum
or cup which receives the head of
the thigh bone.

I'SEEIN. | (from eisen, Germ.) A

I'SERINE. j mineral of an iron-
black colour, from which it derives
its name. It consists of 48 per
cent, of oxide of titanium, an equal
proportion of oxide of iron and four
per cent, of uranium. It occurs in
small obtuse angular grains, being
a kind of metallic sand. It appears
to differ but little from menachinite.

ISOCA'RDIA. A heart-shaped shell,
with separated involuted and di-
verging beaks. The hinge formed
by two flattened cardinal inserted
teeth, and an isolated lateral tooth
under the cartilage slope.

ISOCHEI'MAL. (from r<ro*; equal, and

winter, Gr.) Of the same
winter temperature : lines drawn
through places having the same
winter temperature are denomi-
nated isocheimal lines.

ISO'CHRONAL } (isochrone, Fr. from

ISO'CHRONOTJS. ) iffo<iy and %/>oVo9,
Gr.) Having equal times ; uniform
in time. The isochronal vibrations
of a pendulum are such as are
performed in the same space of
time ; as all the swings or vibra-
tions of the same pendulum are,
whether the arches it describes are
longer or shorter.

PSOGEOTHE'RMAL LINES. (from 10-09,
777, and 0e/yto9, Gr.) Certain lines
or divisions in the earth's crust
possessing an equal degree of mean
annual temperature. If we draw
lines through all the points which
have the same terrestrial tempera-
ture, these isogeothermal lines re-
semble the isothermal, as they are
parallel to the equator, but diverge
from it in several points.

ISOME'RIC. (from "ao?, equal, and
ytte/309, a part, Gr.) A term applied
to substances which consist of the
same ingredients in the same pro-
portion, and yet differ essentially
in their properties.

ISOMO'EPHISM. (from i'aos and /AO/?^,
Gr.) That quality which a sub-
stance possesses of replacing some
other substance in a compound
body, without any alteration of its
primitive form.

ISOMO'RPHOITS. That has the property
of retaining its primitive form when
united with other substances in a
compound body.

ISOPERIME'TRICAL, (from fo-os, vepi,
and fieTpov, Gr.) Such figures as
have equal perimeters or circum-
ferences, of which the circle is the
greatest.

ISO'PODA. (from "ao? and TTOV?, Gr.)
An order of crustaceans, thus named
from the formation of their feet
which are fourteen in number.

I SO

[ 240 ]

J UK

This order embraces the genus
Oniscus.

ISO'SCELES. (iffoffKeXfo, Gr.) That
which hath only two sides equal.

I'SOPYEE. A mineral of a greyish
or black colour. Occurs massive.
Found in Cornwall, imbedded in
granite.

ISO'THEKAL. (from foos and Oepos,
summer, Gr.) Of the same summer
temperature : lines drawn through
places having the same summer
temperature are denominated iso~
tJieral lines.

ISOTHE'EMAL. (from "ao? and O^p^,
Gr. ) Possessing equal temperature.
Lines drawn upon a map through
a series of places having the same
annual mean temperature are termed
isothermal lines, or lines of equal
temperature. Sir C. Lyell observes,
"it is now well ascertained that
zones of equal warmth, both in the
atmosphere and in the waters of
the ocean, are neither parallel to
the equator nor to each other. It
is also discovered that the same
mean annual temperature may exist
in two places which enjoy very
different climates, for the seasons
may be nearly equalized or vio-
lently contrasted. Thus the lines
of equal winter temperature do not
coincide with the lines of equal
annual heat, or isothermal lines. If
lines be drawn round the globe
through all those places which have
the same winter temperature, they
are found to deviate from the ter-
restrial parallels much farther than
the lines of equal mean annual heat.
The lines, for instance, of equal
winter in Europe, are often curved
so as to reach parallels of latitude
9° or 10° distant from each other,
whereas the isothermal lines only
differ from 4° to 5«."

ISOTHE'EMAL ZONES. As the isothermal
lines are as numerous as the places,
and as diversified as numerous,
geographers have grouped them
into bands or zones. Humboldt

has divided the northern hemi-
sphere into six isothermal zones or
bands.

FSOTOME. Isotomes are those bodies
which have the same crystalline
form, and similar formula, and
equal atomic volumes.

ISTIU'EUS. A genus of that family of
saurians called iguanida, and thus
named by Cuvier. The distin-
guishing character of the genus
Istiurus is an elevated and trench-
ant crest, extending along a portion
of the tail, and supported by spi-
nous apophyses of the vertebra.

ITJ'LUS. ) ,,, , n x

JU'LTTS. jO^Gr-)

1. In botany, a catkin; a species
of inflorescence consisting of chaffy
scales arranged along a stalk ; they
are worm-like tufts, which at the
beginning of the year grow out,
and hang pendular down from the
hazel, walnut, filberd, &c.

2. In zoology, a genus of insects of
the order Aptera. The feet are
very numerous, being on each side
twice as many as the segments of
the body ; the antennas are moni-
liform; there are two articulated
palpi ; and the body is of a semi-
cylindrical form. There are many
species.

I'VOBY. (elur, Lat. ivoire, Pr. avdrio,
It.) A hard, solid, and firm sub-
stance, of a white colour, and ca-
pable of a very good polish. It is
the tusk of the elephant. The
ivory from Ceylon is more valuable
than any other, from its not be-
coming yellow in the wearing, as
nearly all other ivory does.

JT/RA LIMESTONE. fcalcaire de Jura,
Jura kalk.J The name given by
some continental geologists to that
group of rocks comprised in the
oolite. The Jura limestone group
is composed of limestones of various
qualities, clays, sands, and sand-
stone, and contains the same fossils
as those found in the oolitic group
of England. In the range of the

J U R

[241 ]

K A 0

Jura and the outer ranges of the
Alps, the calcareous formations are
of such immense magnitude, and
the beds are often so higly indurated
and crystalline, that it is only from
their relative position and imbedded
fossils, that we can trace their
analogy to the English strata.
JURASSIC, (from Jura.) The name
given to certain strata composing
the mountain-chain of the Jura, or
the fossil remains therein contained;
it is synonymous with oolitic ;
the Jurassic system of rocks consist
of three great divisions, the lower

of which is the Lias formation; the
middle includes the Inferior oolite,
the Great oolite, the Cornbrash, the
Kelloway rock, and the Oxford
clay ; the upper is the Coralline
oolite formation, with its subordi-
nate calcareous grits, and the Port-
landian formation, with its subor-
dinate members of Kimmeridge
clay, Portland oolite, and Purbeck
limestone. — LyceU.
JU'XTA-POSI'TIOX. (juxta-position, Fr.
juxta and.positw, Lat.) The state
of being placed in nearness or con-
tiguity; apposition.

KAINOZ'OIC. A term used by Palaeon-
tologists as applicable to strata
containing recent fossil remains; it
is synonymous with tertiary, and
has been divided into the Human,
Historical, or Eecent period ; the
Pleistocene period ; the Pliocene
period ; the Miocene period ; and the
Eocene period.

KAMM. A provincial term, used in
Cornwall, for that portion which
lies over the bed or principal di-
vision of a mineral deposit. The
mineral deposit may be divided
into two parts, the bed or floor,
and the Kamm or overly er.

KANEELSTEIN. \ Names given by Wer-

KANNELSTEIN. f ner, Haiiy, and
others to Cinnamon Stone. — See
Cinnamon Stone.

KANGAROO'. An animal of the genus
didelphys, the Didelphys gigantea
of Linnseus. It is a native of New
Holland. When of full growth, it
attains the size cf a large sheep.
The fore-legs are short, the
hind legs of considerable length, so
that it advances by leaping rather
than walking or running.

KA'OLIN. (The Porzellan Erde of Wer-
ner; the Argile Kaolin of Brong-

niart ; and Feldspath decompose of
Haiiy.) Porcelain clay. The name
of an earth which is used as one of
the ingredients in the manu-
facture of oriental porcelain. Mr.
Bake well observes, " I believe it is
the soft earthy granite from the
mountains of Auvergne which sup-
plies the kaolin used in the porce-
lain manufacture at Sevres. Mons.
Brongniart shewed me a specimen
of their best kaolin : it contained
crystals of pinite." M. Bromare
says that by analysing some Chinese
kaolin, he found it was a compound
earth, consisting of clay, to which
it owed its tenacity ; of calcareous
earth ; of sparkling crystals of
mica; and of small quartz crystals.
He says that he has found a similar
earth upon a stratum of granite,
and conjectures that it may be a
decomposed granite. The kaolin
used in most countries for the
manufacture of fine porcelain or
china, is generally produced from
the felspar of decomposing granite,
in which the cause of decay is the
dissolution and separation of the
alkaline ingredients. Cleveland
says, "Kaolin is essentially com-

i i

K A K

242 ]

K I I

posed of silex and alumine; the
proportions are variable, but the
silex usually predominates. When
pure kaolin is employed in the
manufacture of porcelain, some in-
gredient must be added as a flux, as,
when pure, it is infusible. There
is satisfactory evidence that kaolin
has, in most cases, if not in all,
originated from the decomposition
of rocks abounding in felspar, more
particularly from graphic granite,
which consists almost entirely of
quartz and felspar. According to
"Werner, it is the carbonic acid
which has changed the felspar in
granite and gneiss into kaolin. The
quantity of kaolin, derived from
the felspar of decomposing granite,
shipped from Cornwall to Worces-
tershire for the china manufactories
amounted, in 1816, to 1775 tons.
Prof. Phillips gives the follow-
ing as the analysis of kaolin: "the
kaolin of China consists of silex
71-15, alumine 15-86, lime 1-92,
water 6*73; the kaolin of Cornwall
is composed of alumine 60 '00, silex
40-00

KA'BPHOLITE. | (from «ra/>0os, straw,
CA'BPHOLITE. j and \i0os, a stone,
Gr.) A straw-coloured mineral,
occurring in thin prismatic concre-
tions, and of a fibrous structure.
According to Stromeyer, it consists
of silica 36-15, alumina 28*60, pro-
toxide of iron 2-29, protoxide of
manganese 19*16, lime 0-27, flu-
oric acid 0-47, water 10-78. It is
found in the tin mines of Schlack-
enwald in Bohemia.
KEEL. (Kiel, Germ, quille, Fr.

1 . In conchology, the longitudinal
prominence in the Argonautae.

2. In botany, the term keel is ap-
plied to two of the petals in papi-
lionaceous flowers : the keel is
composed of two petals, separate or
united, and encloses the inter-
nal organs of fructification.

3. In entomology, a sharp, longi-
tudinal, gradually rising elevation
upon the inferior surface.

KEE'LED. Applied to leaves when the
back is very prominent longitudi-
nally.

KELVE. In the south of Ireland, car-
bonaceous shale is called Kelve.

KENTISH BAG. The name given to a
siliciferous limestone with dissemi-
nated dark green particles : it is
found in the lower green sand.

KEBA'TOPHYTE. A name given to the
horny zoophyte.

KEBATO'SA. One of the three orders into
which the class Poriphera has been
divided. The axis of the animal is en-
tirely composed of horny anastomos-
ing filaments, from which circum-
tance the name has been applied.

KE'BS ANTON. A greenstone rock, com-
posed essentially of hornblende and
mica, in which some felspar is often
mixed.

KE'BOLITE. An earthy mineral occur-
ing in Silesia and in Saxony, asso-
ciated with serpentine. According
to Pfaff, it contains silica 37'95,
alumina 12-18, magnesia 16-02,
water 31-00. It is of a white,
yellow, or green colour, and is
found in kidney shaped masses,
which have a lamellar or compound
structure. Feels greasy, but does
not adhere to the tongue.

KE'UPEB. The name given by the
German geologists to one division
of rocks of the Triassic period. The
Marnes Irisees of the French. It
consists principally of red and green
marl.

KI'LLAS. A provincial name for a
coarse argillaceous schist ; a variety
of slate. Mr. Bakewell, in men-
tioning the Icillas of Cornwall, says,
" perhaps the best designation of
the Icillas rock in this situation is,
that of a minutely grained and
highly indurated gneiss that had
lost its schistoze character." Mr.
Hawkins considers the common
Icillas, or slate of the mining dis-
trict, is an intimate mixture of
quartz, with mica, talc, chlorite,
and, perhaps, in some instances,
with felspar. Mohs saysthat Was

K I L

[243]

K Y A

is an intermediate substance be-
tween mica- slate and clay-slate.
Dean Conybeare states that the com-
mon Ullas has been at last admitted
on all hands to be a genuine clay-
slate. Dr. Boase proposes to apply
to the Jcillas the name of Cornubia-
nite. See Cornubianite. Kir wan
gives the following analysis of
killas : 100 grains contained silica
60, alumina 25, magnesia 9, iron 6.

KI'LLINITE. A mineral of a pale green
colour, occuring in veins of granite
at Killiney, near Dublin.

KI'HMERIDGE CLAY. A blue and grey-
ish-yellow slaty clay of the upper
oolite formation ; a member of the
oolite group, thus called from its
being found abundantly at Kim-
raeridge, in the Isle of Purbeck.
It contains gypsum and bituminous
shale. It is a marine deposit.
Kiinmeridge clay forms the base of
the Isle of Portland. The bitumin-
ous shale found in the Kimmeridge
clay on the coast of the Isle of
Purbeck, has obtained the name of
Kimmeridge coal, and is used as
fuel. The most interesting remains
contained in the Kimmeridge clay
are those of the extinct genera
allied to the order Lacerta,
evidently calculated for a marine
abode; the vertebrae, paddles, &c.,
of a species of Ichthyosaurus diff-
ering from those in the lias; the
vertebrae, phalanges, and head of
another saurian, perhaps a variety
of plesiosaurus, have been found at
Kimmeridge and Headington ;
bones, apparently of cetacea, like-
wise appear.

KING-CRAB, (an entomostracan, or
shelled insect.) The Limnlus
polyphemus, known also as the
horse-shoe. It is very common on
the coast of New Jersey. The
king-crab is placed by Cuvier
amongst the pcecilopods.

KNOB, (knolel, hnopf, Germ.) A
hard protuberance. In conchology,
any part of a shell bluntly rising
above the rest.

KOA'LA. An extraordinary quadruped
inhabiting the continent of Austra-
lia. Cuvier placed the koala in
marsupialia, or the fourth order of
Mammalia. This animal has a
short stout body, short legs, and
no tail : it has the five toes, or
ringers, of the fore-feet divided
into two groups, the thumb and
index forming one group, and the
three remaining toes or fingers the
other. On the hind-feet the thumb
is altogether wanting. Carrying
its young for a long period on its
back, this separation of the toes
of the fore-feet enables it to take
firmer hold of the branches of the
trees, on which it passes a portion
of its time.

KOTH. A name given by the Spaniards
to an earthy slimy substance ejected
from the volcanoes of South Amer-
ica. It is of a blackish brown col-
our, an earthy texture, and is but
slightly coherent. The natives call
it Moya.

KOT/PHOLITH. (from /cov0a<?, light,
and X/009, a stone, Gr.) The preh-
nite koupholite of Brongniart:
prehnite lamelliforme rhomboidal,
of Haiiy; a variety of prehnite. It
occurs in minute, rhomboidal plates,
is of a greenish or pale yellow
colour, glistening, and slightly
pearly. It has been found in the
Pyrenees.

KT^ANITE. (from icvavos, blue colour,
Gr. This is frequently written
Cyanite.) The Cyanit of Werner;
the Disthene of Haiiy, and the
Sappare of Kirwan. Kyanite oc-
curs both massive and crystallized,
the crystals, often very long, are
frequently grouped. Its colour, as
its name imports, is blue, varying
from an intense to a light sky-blue.
It is infusible, except under the
compound blow-pipe. It consists
of alumina 64, silica 34, with a
small quantity of oxide of iron and
a trace of lime. It is found in the
primary rocks in Scotland and in
America.

LAB

[244]

LAC

LABE'LLUM. (labellum, Lat. a little
lip.) A term applied, in botany,
to one of the three pieces forming
the corolla in orchideous plants.
The calyx and corolla consist of
three pieces each, and ODC of those
forming the latter, differs very
much in size and form from the
other two; it is called the labellum,
and is often spurred.

LABIATE. | In botany, plants are so

LA'BIATED. j called which have the
segments or divisions of their co-
rollas resembling the form of lips.

LABIATE. There is a large class of
plants called labiates, which have
irregular monopetalous corollas,
and these, generally, bibaliate and
ringent ; the mint, nettle, &c. are
examples.

LA'BIUH:. (labium, Lat.)

1 . In entomology, the lower lip of
insects is called the labium ; the
upper, the labrum. The lower
pair of jaws are behind the mandi-
bles, and between them is situated
the labium, or lower lip, which
closes the mouth below, as the
labrum does above. The labium of
insects consists of two chief parts,
each of which may be considered
as a separate organ; namely, the
chin and the tongue.

2. In conchology, the inner lip of
the shell.

LA'BRUM. (labrum, Lat.)

1. In entomology, the upper lip of
insects. The labrum is situated
above, or rather in front of, the
mandibles, it is generally of the
form of the segment of a circle, or
a triangular, or quadrangular,
somewhat convex, corneous plate,
which is united posteriorly by a
membranous hinge with the cly-
peus.

2. In conchology, the outer lip ;

that edge of the aperture which is
placed at the greatest distance from
the axis of the shell.

LA'BRADOR FELSPAR. | So named from

LA'BRADOR STONE, j having been
found on the coast of Labrador,

This mineral was at one time
called Labrador Hornblende, but
its present name has been substi-
tuted for what was incorrect.
Labrador felspar has been found
massive and disseminated only. Its
laminaa are slightly curved ; lustre
nearly metallic, and pearly on the
perfect cleavage faces. It is dis-
tinguished by its splendid change-
ability of colour, reflecting very
beautiful colours when the light
falls upon it in certain directions.
This mineral has been also found in
different parts of Europe.

LA'BYRINTH. (labyrinthus, Lat. \afiv-
plvOo-s, Gr. labyrinths, Fr. laberinto,
It.) The name given to several
cavities of the ear, from their flex-
uous position. The internal parts
of the ear compose what is desig-
nated, from the intricacy of its
winding passages, the labyrinth.

LABRYRI'NTHODON. Called also Mas-
todonsaurus. A name proposed to
be given by Prof. Owen to a genus
of reptiles, the remains of which
have been discovered in the War-
wick sandstone. The Labryrin-
thodon belongs to the extinct order
Labyrinthodonta.

LABYRI'NTHODONTA. An extinct order
of the class Amphibia, comprising
Labryrinthodon; Capitosaurus; Me-
topias; Trematosaurus; Zygosau-
rus; Odontosaurus; Archegosaums;
Rhinosaurus ; and Telerpeton.

LACERT'ILIA. The third order of the
class Eeptilia.

LAC'ERTA. (The lizard.) A genus of
reptiles of the order Lacertilia.

LAC

[245]

LAG

LACI'NIATE. } (laciniatus, Lat. lacinie,

LACI'NIATED. j Fr.) Ragged at the
edges; jagged. In botany, applied
to leaves cut into numerous irre-
gular portions.

LA'CBYHAL. (from lachryma, vel la-
cryma, Lat. lacrymale, Fr.) Certain
parts about the eye, connected with
the secretion and passage of the
tears, as the lacrymal glands, the
lacrymal ducts, &c. This word is
also written lachrymal.

LA'CTEAL. (from lac, Lat.) The lac-
teals are numerous minute tubes
commencing, by open and very
minute orifices, from the inner
surface of the intestines, and uni-
ting successively into larger vessels,
till they form trunks of consider-
able magnitude. The office of the
lacteals is to take up the chyle and
transmit it to the heart. It is
only among the vertebrata that
lacteals are met with; in inverte-
brated animals, the absorption of
the chyle is performed by veins
instead of lacteal vessels. The
chyle of the higher orders of ani-
mals often contains a multitude of
globules, which give to it a milky
appearance, from which circum-
stance the vessels containing it have
obtained their name.

LACU'STEINE DEPOSITS. Purely lacus-
trine deposits are almost unknown
among any of the stratified rocks
of a date earlier than the tertiary
period, and it was not until the
publications of Cuvier and Brong-
niart, on the environs of Paris,
that the attention of geologists was
much directed to the study of those
numerous fresh- water deposits from
which we may obtain a knowledge
of the ancient condition of the land.
"If we drain a lake," says Sir C.
Lyell, " we frequently find at the
bottom a series of deposits, disposed
with great regularity one above
the other; the uppermost, perhaps,
may be a stratum of peat, next
below a more compact variety of

the same, still lower a bed of lami-
nated marl, alternating with peat,
and then other beds of marl, alter-
nating with clay. Now if we
sink a second pit through the same
continuous lacustrine deposit, at some
distance from the first, we commonly
meet with nearly the same serie*s
of beds, yet with slight variations ;
some, for example, of the layers of
sand, clay, or marl may be wanting,
one or more of them having thinned
out, and given place to others, or
sometimes one of the masses, first
examined, is observed to increase
in thickness to the exclusion of
other beds. At length we arrive
at a point where the whole assem-
blage of lacustrine strata terminate,
as, for example, when we arrive at
the borders of the original lake-
basin."

LAGA'NUM. A fossil echinite thus
named by Klein, called also pan-
cake.

LAG'OMYS. (from \a<yo<?, a hare, and
/«><?, a rat, Gr.) A rat hare. A
genus of animals forming a link
between the hare and the rat. The
lagomys is placed by Cuvier in the
order rodentia. They have been
found in Siberia, and are described
by Pallas. There are several species.
The lagomys has ears of a moderate
size; legs nearly alike; clavicles
almost perfect ; and no tail. The
Rev. W. Kirby observes of the
lagomys, "it ought rather to have
been called the hay-maker, since
man may, or might, have learned
that part of the business of the
agriculturist, which consists in
providing a store of winter pro-
vender for his cattle, from this
industrious animal. The Tungu-
sians, who inhabit the country
beyond the lake of Baikal, call it
PiJca, which has been adopted as its
trivial name. These animals make
their abode between the rocks, and
during the summer employ them-
selves in making hay for a

LAG

[246 ]

LAM

winter store. About the middle of
August these little animals collect
with admirable precaution their
winter's provender, which is formed
of the choicest grasses and the
sweetest herbs, which they bring
near their habitations and spread
out to dry like hay. In September,
they form heaps or stacks of the
fodder they have collected, under
the rocks, or in other places shel-
tered from the rain or snow. Where
many of them have laboured to-
gether, their stacks are sometimes
as high as a man, and more than
eight feet in diameter. A sub-
terranean gallery leads from the
burrow, below the mass of hay, so
that neither frost nor snow can
intercept their communication with
it. — Bridgewater Treatise.

LAGOO'N. | (laguna, It.) A salt-water

LAGU'NE. j lake. This term is more
particularly applied to those pools
of water which are found in the
centre of coral reefs.

LAMA'NTIN. | ThemanatusofCuvier.

LAMA'NTINE. j A species of herbiv-
orous cetacea, living upon the
plants which grow at the bottom
of the sea. The lamantin appears to
have existed during the miocene
and pliocene periods. Fossil re-
mains have been discovered in
France. The fossil remains of the
lamantin s differ sufficiently from
the analogous parts of existing
species to justify the inference of
specific distinction. It would also
appear that they belonged to a lost
species. The existing species of
the lamantine are found near the
mouths of rivers in the hottest parts
of the Atlantic ocean and in the
torrid zone, and the discovery of
their fossil remains in Europe adds
another link to the long chain of
evidence of a diminished tempera-
ture of the climate of Europe.

LAMBDOI'DAL. (from the Greek letter
\a/ida, and etdos, form.) The name
given to one of the sutures of the

cranium, from its supposed resem-
blance in form to the Greek
letter A.

LA'MELLATED. j Composed of thin

LAMF/LLAR. j plates, layers, or
scales. In conchology, when a
shell is divided into thin and dis-
tinct plates or layers, overlying
each other with the edges produced.

LAME'LLI BRANCHIA'TA. In De Blain-
ville's conchological arrangement,
the third order of Acephalopora,
containing ten families of bivalves.
Lamelli branchiata or Acephala
comprises the cockle, mussel,
oyster, Venus, and all ordinary
bivalve shells.

LAMELLICO'RNES. In Cuvier's ar-
rangement, the sixth family of
pentamerous coleoptera ; they have
foliated horns, from which circum-
stance they obtain their name.

LAMELLI'FEROUS. (from lamella, a
small plate, and fero, to bear, Lat.)
Having a structure composed of
thin layers ; having a foliated
structure.

LAMELLI'FORM. Consisting of lamellae
or regular and parallel plates.

LAMELLIRO'STRES. In Cuvier's ar-
rangement, the fourth family of
the order of Palmipedes. The
lamellirostres have a thick bill, the
edges of which are furnished with
laminae, from which circumstance
they have obtained their name.

LA'MINA. (lamina, Lat.) A thin
plate or scale ; a thin layer of a
stratum.

LA'MINATED. (lamine, Fr.) Disposed
in layers, placed one over another.

LAMINA' TION. Arrangement in layers.
Lamination prevails amongst all
the varieties of gneiss, mica schist,
chlorite schist, hornblende schist,
&c. It is often observable in
primary limestone, and sometimes
in quartz rock. All the members
of the carboniferous series display
lamination, though in unequal
degrees. By laminae and lami-

LAM

[247]

LAP

nation are always meant layers of

deposition.
LAMN'ODUS. A genus of ichthyolites

of the old red sandstone formation,

called also Dendrodus, (but which

latter has been supplanted,) of

which three species have been

described by Agassiz.
LA'NATE. | (from lanatus, Lat.)
LA'NATED. j Woolly; covered with

a sort of pubescence resembling

short woolly hairs.
LA'NCEOLATE. Lance-shaped ; narrow

and tapering.

1. In conchology, applied to a
shell of an oblong shape, and
gradually tapering at each end.

2. In entomology, in describing
the figure of the superficies, when
the base is not so broad as the
centre, and the lateral margins
slightly, but equally swollen,
gradually tapering towards the
apex, where it terminates in a
point, and the longitudinal diameter
more than three times the length
of the transverse. — Burmeister.

3. In botany, applied to leaves of
a narrow oblong form, gradually
tapering towards each end.

LA'NCIFORM. (from lancea and/on/^,
Lat.) Spear-shaped; lance-shaped.

LA'NDSLIP. A portion of land that
has separated from the main body,
in consequence of long- continued
rains, or the expansive powers of
severe frosts, and has fallen to a
lower situation. Landslips must
necessarily be often attended by
fatal consequences, as in the falls
of avalanches. We are informed
that when the mountain of Piz fell,
in 1772, three villages, with the
entire population, were covered ;
and that when part of Mount
Grenier, in Savoy, fell, in 1248,
five parishes were buried, the ruins
ocupying an extent of nine square
miles.

LA'NGOUSTE. (Fr. sorte d?6crevisse de
mer.) The name given by the
French to the Palinurus vulgaris of

Leach; the cray-fish or thorny
lobster.

LA'NTANE. j (from \avdavuo, to con-

LA'NTHANUM. ) ceal, Gr.) One of
the elementary bodies, its symbol
being La.

LANU'GINOSE. | (from lanuginosus,

LANT/GUNOUS. j Lat.) In entomo-
logy, when longish curled hair is
spread over the surface; covered
with soft hair resembling wool.

LA'PIDES JTJDA'ICT. A name given to
certain fossil spines of echinites,
formerly supposed to be petrified
olives.

LAPIDIFICA'TION. (lapidification, Fr.
from lapis, a stone, andyzo, to make
or become, Lat.) The conversion
into stone of some other substance ;
the act of forming stone.

LAPI'LLI. (lapillus, Lat.) Volcanic
cinders, abounding in minute glo-
bular concretions.

LA'PIS LA'ZULT. The Lazurstein of
Werner ; Azure-stone of Jameson ;
Lazulite of Haiiy ; Dodecaedrischer
Kuphon-spath of Mohs. When
lapis lazuli is pure, it is a mineral
of a fine azure-blue colour ; it
occurs in rhombohedral dodecahe-
drons, massive, and disseminated.
Structure finely granular, almost
compact ; fracture uneven or con-
choidal; lustre feeble; a little
translucent at its edges. It scratches
glass, but gives sparks with steel
with difficulty. Specific gravity
about 2*30. Its analysis is very
differently given by different auth-
ors. It contains silica, nearly
fifty per cent, carbonate of lime,
alumina, potash, soda, oxide of
iron, and sulphuric acid. It occurs
associated with primary rocks, es-
pecially granite. It is accompanied
by garnets, quartz, felspar, &c.,
with some of which it is often
intermixed. It is found chiefly in
China, Persia, and Russia. It is
capable of a high polish, and is
much esteemed. Its chief use,
however, is to furnish the ultra-

LAP

[248 ]

LAV

marine blue, used by painters, a
pigment remarkable for the dura-
bility of its colour.

LA'PIS CETI'TES. Eagle- stone. A min-
eral which derives its name from
the ancient belief that it was found
in the nests of the eagle. It is a
variety of iron ore, commonly met
with in the argillaceous mines of
this country. Its supposed virtues
are described by Dioscorides, (Etius,
and Pliny, who assert that if tied
to the arm it will prevent abortion ;
if fixed to the thigh it will facili-
tate delivery.

LA'BYNX. (\dpvyg, Gr.) The upper
part of the wind-pipe or trachea ;
that cartilaginous projection in the
throat known as the pomum
Adami, which strictly is formed
by one of the cartilages of the
larynx only, namely, the thyroid.
The larynx consists of five cartila-
ges, the cricoid, thyroid, two ary-
tsenoid, and the epiglottis.

LA'TERITE. The name given to a
ferruginous clay, mottled red and
yellow. When first dug from its
bed, it is soft and easily fashioned
into the form of bricks or large
square masses for building; it
rapidly indurates on exposure to
the atmosphere, and, as far as is
yet known, is destitute of fossils.

LATIRO'STEOUS. (from latus, broad,
and rostrum , a beak, Lat.) Broad
beaked.

LA'TITUDE. (latitude, Lat. latitude, Fr~
latitudine, It.) The latitude of a
place on the earth's surface is its
angular distance from the equator,
measured on its own terrestrial
meridian : it is reckoned in degrees,
minutes, and seconds, from 0 up to
90°, and northwards or southwards
according to the hemisphere the
plane lies in. Thus the observa-
tory at Greenwich is situated in
51° 28' 40" north latitude. Lati-
tude may also be thus defined, the
angular distance between the di-
rection of a plumb-line at any

place and the plane of the equator.

LA'TROBITE. A mineral, thus named
after Latrobe, having been found
by him on the coast of Labrador.
Colour, pale pink ; specific gravity
2 -8. Occurs massive and crys-
tallized.

LA'TTICED. In conchology, shells
having longitudinal lines or furrows
decussated by transverse ones, re-
sembling lattice-work.

LA'RVA. (larva, a mask, Lat.) An
insect in its caterpillar state, before
it has attained its winged or
perfect state. Some insects, as the
butterfly, moth of the silkworm,
&c., pass through four distinct
states, namely, the egg ; the larva,
or caterpillar ; the pup% or chry-
salis; and the imago, or perfect
insect. The egg, which is de-
posited by the perfect insect, gives
birth to a caterpillar, or larva ;
an animal, which, in outward
shape, bears not the slightest re-
semblance to its parent, or to the
form it is itself afterwards to
assume. It has, in fact, both the
external resemblance, and the
mechanical structure, of a worm.
The same elongated cylindric
shape, the same annular structure
of the denser parts of the integu-
ment, the same arrangements of
longitudinal and oblique muscles
connecting these rings, the same
apparatus of short feet, with claws,
or bristles, or tufts of hair, for
facilitating progression ; in short,
all the circumstances most charac-
teristic of the vermiform type are
equally exemplified in the different
tribes of caterpillars, as in the
annelida. These external invest-
ments, which hide the real form of
the future animal, have been
compared to a mask; so that the
insect, while wearing this disguise,
has been termed larva, the Latin
name for a mask. — Roget.

LA'VA. (This word, according to
Kirwan, is derived from the Gothic,

LAY

[249 ]

LAV

lopa or lauffen, to run, and is applied
to the melted and liquified matter,
discharged from the mouths of
volcanoes.) The matter which
flows in a fused, or melted, state
from a volcano.

Lava, whatever be its chemical
composition, puts on very different
appearances, according to the cir-
cumstances which accompany its
consolidation, hence by some au-
thors it has been divided into
compact lava, cellular lava, and
cavernous lava. The mineral called
felspar forms, in general, more than
half of the mass of modern lavas.
When this is in great excess, lavas
are called trachytic ; when, on the
other hand, augite prevails, they
are called basaltic. Lavas occur
of an intermediate composition,
and these, from their colour, have
been called gray-stones. When
lava is observed as near as possible
to the point whence it issues, it is
found to be, for the most part, a
semi-fluid mass of the consistence
of honey, but occasionally so
liquid as to penetrate the fibre of
wood. It soon cools externally,
and consequently exhibits a rough
uneven surface ; but, from its
being a bad conductor of heat,
the internal mass remains liquid
long after that portion which
is exposed to the air has become
solid. That of 1822, some days
after it had been ejected, raised the
thermometer from 59° to 95°, at a
distance of twelve feet ; at a dis-
tance of three feet, the temperature
greatly exceeded that of boiling
water. The temperature at which
lava continues in a state of fluidity
is sufficiently great to melt glass
and silver ; even stones are said to
have been fused when thrown into
the lava of Etna and Vesuvius.
The length of time during which
streams of lava retain their heat is
quite astonishing : the current of
lava which flowei from Etna in

1669 retains a portion of it to the
present time. That which was
poured from Jorullo, in Mexico, in.
the year 1759, was found to retain
a high temperature half a century
afterwards. Sir W. Hamilton
lighted small pieces of wood in the
fissures of a current of Vesuvian
lava four years after it had been
ejected. The streams of lava often
become solid externally, even while
yet in motion, and their sides may
be compared to two rocky walls,
which are sometimes inclined at an
angle of 45°. Of the immense
bodies of lava thrown out during
volcanic eruptions, few persons en-
tertain a just idea. Etna, which
rises upwards of 10,000 feet in
height, and embraces a circumfer-
ence of 180 miles, is composed en-
tirely of lava. " In the structure
of this mountain," says Dr. Dau-
beny, " every thing wears alike
the character of vastness." The
products of the eruptions of Vesu-
vius may be said almost to sink
into insignificance, when compared
with these coulees, some of which
are four or five miles in breadth,
fifteen in length, and from fifty to
one hundred feet in thickness. Still
the eruptions of Etna are nothing
when compared with that of Skap-
tar Jokul. " On the llth of June
Skaptar Jokul threw out a torrent
of lava which flowed down into
the river Skapta, and completely
dried it up. The channel of the
river was between high rocks, in
many places from four hundred to
six hundred feet in depth, and
near two hundred in breadth. Not
only did the lava fill up these great
defiles to the brink, but it over-
flowed the adjacent fields to a
considerable extent. The burning
flood, on issuing from the confined
rocky gorge, was then arrested for
some time by a deep lake, which
it entirely filled. The current
then again proceeded, and reaching

LAV

some ancient lava, full of subter-
raneous caverns, penetrated and
melted down part of it. On the
18th of June, another ejection of
liquid lava rushed from the volcano,
which flowed down with amazing
velocity over the surface of the first
stream. After flowing for several
days, it was precipitated down a
tremendous cataract called Stapa-
foss, where it filled a profound
abyss, which that great waterfall
had been hollowing out for ages,
and again the fiery current pursued
its onward course. On the 3rd of
August, fresh floods of lava still
pouring from the volcano, a new
branch was sent off in a different
direction. "When the fiery lake
which filled up the lower portion
of the valley of the Skapta had
been augmented with new supplies,
the lava flowed up the course of
the river to the foot of the hills
whence the Skapta takes its rise.
This eruption did not entirely cease
till the end of two years, and al-
though the population of Iceland
did not exceed fifty thousand, not
fewer than twenty villages were
overwhelmed, besides those inun-
dated by water, and more than
nine thousand human beings per-
ished, together with an immense
number of cattle. Of the two
branches of liquid lava, which
flowed in nearly opposite directions,
the greater was fifty, and the lesser
forty miles in length. The extreme
• breadth which the Skapta branch
attained in the low countries was
from twelve to fifteen miles, that
of the other about seven. The
ordinary height of both currents
was one hundred feet, but in nar-
row defiles it sometimes amounted
to six hundred." The sources
from which lava ascends are deeply
seated beneath the granite ; but it
is not yet decided whether the
immediate cause of an eruption be
the access of water to local accu-

[ 250 ] L A U

mulations of the metalloid bases of
the earth and alkalies ; or whether
lava be derived directly from that
general mass of incandescent ele-
ments, which may probably exist
at a depth of about one hundred
miles beneath the surface of our
planet. — Lyell.

LATJ'MONITE. Diatomous zeolite. Lo-
monit of "Werner : Mesotype Lau-
monite of Brongniart : Zeolite eff-
lorescente of Brochant : Diatomous
Kouphone Spar of Mobs. A miner-
al long known under the name of
efflorescent zeolite, and to which
its present name has been assigned
by Werner, in honour of M. Gillet
de Laumont, to whom we are in-
debted for our first knowledge of it.
It is of a white, or grayish- white
colour, sometimes tinged with red.
It occurs regularly crystallized, and
in distinct granular concretions.
Its crystals are four- sided prisms,
slightly oblique, sometimes termi-
nated by dihedral summits, some-
times truncated on their lateral
edges. The height of the prism is
to the edges of the terminal faces,
in the ratio of eight to seven. This
prism divides in a direction parallel
to all its planes, but much more
easily longitudinally than on its
terminal surfaces ; this division
takes place also with greater faci-
lity on two of the opposite sides
than on the two others. "When
Laumonite has not been altered by
exposure to the atmosphere, it cuts
glass easily. By exposure to the
air, Laumonite disintegrates, and
is at length reduced to a white
powder. If, however, recent spe-
cimens be immersed for two or
three hours in a strong mucilage of
gum, the action of the atmosphere
upon them, and their efflorescence,
will be prevented. By the action
of acids, Laumonite is reduced to a
state of jelly. Under the blow-pipe
it fuses, with a slight degree of
ebullition, and affords a perfectly

L A

[251 ]

LEG

opaque and beautifully white ena-
mel. Specific gravity 2 '23. Lau-
monite consists of silica 52, alumina
21-20, lime 10-50, and water about
14. It occurs in secondary trap-
rocks in France, Scotland, Iceland,
and America.

LA'ZULITE. A mineral of a light blue
colour, supposed by some mineralo-
gists to be a sub-species of lapis lazuli.

LEAD, (lad, Sax.) Lead is of a bluish-
grey colour, with considerable lus-
tre, but soon tarnishes by exposure
to the atmosphere. By friction,
this metal exhales a peculiar, and
somewhat disagreeable odour. Its
specific gravity is 1T35, or nearly
eleven and a-half times heavier than
water. It is soft and easily melted,
being fusible at about 600° Fahren-
heit. It is the softest of all the
durable metals; it can be scratched
by the nail, and is easily cut by a
knife. Its elasticity, ductility, and
tenacity are comparatively low ; it
cannot be drawn into wire thinner
than a line in diameter. Lead is
very malleable, and can be beaten
into thin leaves; but these, from
its imperfect tenacity, are easily
torn. All the salts of this metal
are highly poisonous ; they are,
however, most shamefully employed
by unprincipled persons to correct
or conceal the acidity of cider and
wines. The presence of lead in
these liquors may be detected by
the following means. Dissolve 120
grains of sulphuret of lime, and
180 grains of supertartrate of po-
tash in 16 ounces of distilled water,
by repeatedly shaking the mixture;
when perfectly dissolved, leave the
mixture to settle, and pour off the
clear liquid into clean phials, adding
about twenty drops of hydrochloric
acid to each. A small quantity of
this poured into a wine-glass of the
suspected wine, will detect the
smallest quantity of lead, if any be
present, by producing a black pre-
cipitate.

Several instances of the occur-
rence of native lead have been
mentioned, though in few of them
does the fact appear to be well
established. In the island of Ma-
deira, it is found in small masses,
in lava, and has undoubtedly been
reduced to its present state by vol-
canic fire. Next to iron, lead may
be considered the most abundantly
diffused of all the metals; it has
been known from the earliest ages.
The lead of our mines is in a state
of combination with sulphur, form-
ing a sulphuret of lead; this is
called galena, or lead-glance. By
exposure to a strong heat, the sul-
phur is driven off and pure lead is
obtained: the average produce of
metal from the Derbyshire ore is
about 66 per cent. The present
annual produce of lead in the "Uni-
ted Kingdom may be computed at
from 47,000 to 50,000 tons.

LEE'LITE. (thus named after Dr. Lee,
of Cambridge.) An earthy mineral,
first noticed by Dr. Clarke, is found
at Gryphitta, in Sweden. It is
compact and massive, of a deep
flesh-red colour. Texture wax-like,
with the lustre and transparency of
horn. Fracture resembling that of
flint. Specific gravity 2- 71. Its
constituents are silica 75, alumina
22, manganese 3, or manganese
2-50, and water 0-50.— Phillips.

LEGU'ME. flegumen, Lat. legume, Fr.
legume, It.) A species of fruit;
a pod; a seed vessel peculiar to
leguminous plants, formed of two
oblong valves having no longitu-
dinal partition; the seeds are at-
tached to one of its margins only ;
the bean, pea, vetch, and all the
natural order of Ieguminosa3 furnish
examples.

LEGUMINO'S^J. An order of plants,
calyx five -toothed, inferior, the odd
segment anterior, or farthest from
the axis; corolla papilionaceous,
rarely regular ; stamens definite or
indefinite, perigynous, either dis-

LEG

[ 252 ]

L E

tinct, monadelphous or diadelphous;
ovarium superior, one-celled, many
seeded, style and stigma simple;
fruit a legume, or, rarely, a drupe;
seeds occasionally with an arillus ;
embryo, exalbuminous; cotyledons,,
either remaining under ground, or
appearing above, in germination ;
leaves compound, stipulate, alter-
nate; leaflets stipulate; inflores-
cence usually axillary, but various.
One genus of this order, Deta-
rium, has a drupe for its fruit, and
Mimosa has a perfectly regular
corolla.

The order Leguminosae is most
important to man both for its beauty
and utility. The pea, bean, harico,
vetch, liquorice, clover, sainfoin,
lucerne, tamarind, indigo, gum
arabic, &c., &c., belong to it. Gen-
erally, the order is innocent, if not
wholesome; but some few genera
are poisonous.

LEGUMINOSI'TES. The name given by
Mr. Bowerbank to certain fossil
seeds found in the London clay.
He describes them as seeds of true
Leguminosa, the pericarps of which
are not known. These seeds pre-
sent, both in form and structure,
all the characteristic features ob-
servable in numerous recent genera
of true leguminous fruits. Mr.
Bowerbank has described eighteen
species, and says it would, however,
- be extremely difficult, if not im-
possible, to identify these seeds
with those of existing genera, sup-
posing them to belong to such,
without the assistance of their per-
icarps.

LEGU'MINOUS. Belonging to the order
Leguminosas; bearing pods; hav-
ing a legume for a pericarp.

LEHM. A German word, being another
name for the deposit now common-
ly known as loess. See Loess.

LE'MMING. The Lapland marmot.
The lemming has short ears and a
tail, with the toes of its fore-feet
peculiarly adapted for digging.

Cuvier places the lemming in the
order Ilodentia, class Mammalia.
Bones of the lemming have been
found fossil in a breccia at Cette.

LE'MNIAN EAETH. A mineral found
in the island of Lemnos, in the
Egean Sea, whence its name. It
is also called Sphragide, from
a(f)pa^, sigillum, a seal. It is of a
reddish colour and has a soapy feel.
It is dug once a year, with much
ceremony, in the Isle of Lemnos.
It was formerly used in medicine ;
when impressed with the seal of
the Grand Seignior, it was sold
under the name of terra sigillata.

LENS, (lens, a lentil, Lat. lentille,
Fr. lente, It.) So named from its
resemblance to a seed of the lentil.
A transparent substance having its
two surfaces so formed that the
rays of light, in passing through it,
have their direction changed. Of
lenses there are various sorts; a
spherical lens, is a sphere, all the
points in its surface being equally
distant from the centre. A double
convex lens, is a solid formed by two
convex spherical surfaces, having
their surfaces on opposite sides of
the lens. When the radii of its two
surfaces are equal, it is said to be
equally convex; when the radii are
unequal, it is said to be unequally
convex. A plano-convex lens, is a
lens having one of its surfaces con-
vex and the other plane. A double
concave lens is a solid, bounded by
two concave spherical surfaces, and
may be either equally or unequally
concave. A plano-concave lens, is a
lens one of whose surfaces is con-
cave and the other plane. A men-
iscus, is a lens one of whose surfaces
is convex and the other concave,
and in which the two surfaces meet
if continued. A concavo-convex lens,
is a lens one of whose surfaces is
concave and the other convex, and
in which the two surfaces will not
meet if continued.

LENTICE'LL^:. The name given by

L E N

253 ]

L E P

DeCandolle to certain points, which
appear as dark spots, on the surface
of the bark of plants.

LENTI'CULAB. (lenticular is, resembling
a lentil, Lat. lenticulaire, Fr.) Ha-
ving the form of a lens.

In entomology, a round body,
with its opposite sides convex,
meeting in a sharp edge. In con-
chology, doubly convex shells.

In mineralogy, crystals nearly
flat, and convex above and beneath.

LENTI'CTJLAK ORE. The name given
by Jameson to obtuse octahedral
arseniate of copper ; called also len-
ticular arseniate of copper.

LENTICULI'NA. A sublenticular, mul-
tilocular, spiral univalve ; a genus
of microscopic foraminifera. Dis-
tinguished from Nautilus by having
no syphon.

LENTI'CTJLITE. A fossil shell of a
lenticular form.

LE'NZINITE. A mineral found in Ger-
many, and thus named after Lenzi-
us, a German mineralogist. There
are two kinds of lenzinite, the opa-
line and the argillaceous ; the for-
mer of a milk-white, the latter of
a snow-white colour.

LE'PADITES. The goose-barnacle. An
order of Cirripedes, the species of
which are distinguished by a ten-
dinous, contractile, and often long
tube, fixed by its base to some
solid marine substance, supporting
a compressed shell, consisting of
valves united to each other by
a membrane ; and by having six
pairs of tentaculated arms. They
are usually found in places exposed
to the fluctuations of the waves. —
Kirby.

LE'PAS. (\67ras, Gr. lepas, Lat. lepas,
Fr.) LinnaBus included under the
name lepas all the cirripedes or
multivalves. These animals are
known in this country by the name
of Barnacles. The lepas, or barna-
cle, constitutes a connecting link
between molluscous and articulated
animals ; the gills are attached to

the bases of the cirrhi, or jointed
tentacula. In the Linnaaan system,
the lepas constitutes the second
genus of multi valve shells. The
animal a tritonj shell affixed at
the base, and consisting of many
unequal erect valves. They are
without eyes, or any distinct head
have no powers of locomotion, but
are fixed to various bodies. Their
body, which has no articulations,
is enveloped in a mantle: their
mouth is armed with transverse
toothed jaws in pairs, and furnished
with a feeler. This genus consists
of two families, or divisions, very
different in their form, the first of
which is the Balanites, or Acorn-
barnacles, having a shelly instead
of a tendinous tube, with an oper-
culum or lid, consisting generally
of four, but sometimes of six valves,
and being of a sub-conic form. The
second family consists of the Lepa-
dites or Goose- barnacles, the species
of which are distinguished by a
tendinous, contractile, and often
long tube or pedicle, which, being
of a flexible nature, allows the
animal, fixed by its base to some
solid marine substance, to writhe
about in quest of food. The ani-
mals of this genus have only been
found in the ocean.
LEPIDODE'NDEON. (from Xe7r«s, a scale,
and SevSpov, wood, Gr.) An ex-
tinct genus of fossil plants, of very
frequent occurrence in the coal for-
mation. Count Sternberg has thus
divided the Lepidodendra : —
Tribus 1. (Lepidotae) squamis
convexis.
a. Scutata3.
I. Escutata3.

Tribus 2. (Alveolariaa) squamis
subconcavis.

It is stated by Lindley and Hut-
ton that plants of this genus are,
next to the calamites, the most
abundant of the fossils in the coal
formation of the north of England.
Lepidodendra are sometimes found

E P

[254]

L E P

of enormous size, fragments of
stems occurring upwards of forty
feet in length. Their internal
structure has been ascertained to be
intermediate between coniferse and
Iycopodiacea3. In some points of their
structure they resemble coniferse,
but in other respects, setting aside
their great magnitude, they may be
compared to lycopodiaceas. To bot-
anists, this discovery is of very
high interest, as it proves that those
system atists are right, who contend
for the possibility of certain chasms
now existing between the grada-
tions of organization, being caused
by the extinction of genera, or even
of whole orders, the existence of
which was necessary to complete
the harmony which it is believed
originally existed in the structure
of all parts of the vegetable king-
dom. By means of Lepidodendron,
a better passage is established from
flowering to flowerless plants, than
by either equisetum or cycas, or any
other known genus. — Lindley and
Button.

LE'PIDOIDS. A family of extinct fossil
fishes, found in the oolitic series ;
they were remarkable for their
large rhomboidal bony scales, which
were of great thickness, and cov-
ered with enamel. The scales of
lepidoids had a remarkable struc-
ture in being furnished on their
upper margin with a hook-like pro-
cess, placed like the hook or peg
near the upper margin of a roofing
tile ; this hook fitted into a depres-
sion on the lower margin of the
scale placed immediately above it.

LEPI'DOLITE. (from XeTrte, a scale,
and X/0os, a stone, Gr.) The Lep-
idolith of "Werner ; Hemiprismat-
ischer Talk-glimmer of Mobs. A
mineral of a peach-blossom, red,
and sometimes grey colour, occur-
ring massive and in small concre-
tions. This mineral, at first view,
appears to be composed of small
grains, sometimes extremely mi-

nute ; but these grains, among
which little pearly scales are often
interspersed, are themselves com-
posed of a great number of minute
folise or spangles, like those of mica,
from which circumstance it has
obtained its name. Its constitu-
ents have been variously stated.
According to some authors, it con-
tains silica 50-36, alumina 28-32,
potash 9-0, oxide of manganese
1'25, fluoric acid and water 5 '40,
lithia 5'50. It exhibits two axes
of double refraction, from which
circumstance it has been called
Di-axial mica. Prom the beauty
of its colour it has been cut into
snuff-boxes.

LEPLDO'PTERA. (from XeTm-, a scale,
and Tnepov, a wing, Gr.) Scaly-
winged insects. Lepidoptera form
the tenth order of insects in Cuvier's
arrangement; they have four wings,
both sides of which are covered
with small coloured scales, resem-
bling farinaceous dust. This order
comprises butterflies, moths, and
sphinxes. The scales are attached
so slightly to the membrane of the
wing as to come off when touched
with the fingers, to which they
adhere like fine dust. When ex-
amined with the microscope, their
construction and arrangement ap-
pear to be exceedingly beautiful,
being marked with parallel and
equidistant stria?, often crossed by
still finer lines. The former of
these scales are exceedingly diver-
sified, not only in different species,
but also in different parts of the
same insect The proboscis of the
Lepidoptera is a double tube. In
the classification of the most mod-
ern naturalists, Lepidoptera consti-
tutes the fifth order of the class
Insecta ; sub-kingdom Annulosa.
LEPIDO'PTEEAL. } Belonging to the
LEPIDO'PTEKOUS. ) order Lepidoptera ;

having wings covered with scales.
LEPIPO'STETJS. | (The Lepisosteus of
LEPISO'STETJS. j Lacepede. A genus

L E P

[255 ]

L I A

ofiishes inhabiting the rivers of
North America, one of the two
living representative genera of
Sauroid fishes. Teeth of a fish
related to Lepidosteus, or Lepisos-
teus, have been found in the Til-
gate beds and in those of Stones-
field.

LEPIDO'STEOBUS. | A genus of extinct
LEPIDO'TUS. j fresh water fishes,
with very thick, enamelled, rhom-
boidal scales, and obtuse hemi-
spherical teeth; the latter are
called fishes' eyes by the common
people who collect them.
LEPTJE'NA. (from XeTrros, tenuis, Gr.)
A sub-division of the family of Te-
rebratula, established by Dalman.
The name Leptsena may be deemed
synonymous with Productus or
Producta, but the latter being ob-
jected to, it has been thought de-
sirable to adopt that of Leptaena
instead. Some authors separate
Leptsena from Productus from the
character of the hinge, which is
compressed and rectilinear, fre-
quently exceeding the width of
the shell. — See Producta.
LET/CIN. | (from \CVKOS, white, Gr.)
LET/CTNE. ) The name given by M.
Braconnot to a white substance
obtained from muscular fibre, by
treating it with sulphuric acid, and
subjecting it to a peculiar process.
LEI/CITE. (from XevAcos, white, Gr.)
A mineral of a white colour, found
in volcanic rocks. Notwithstand-
ing its name, leucite is not always
white, its common colours are
yellowish and greyish white, but it
is occasionally of a reddish white,
and translucent. Before the blow-
pipe it is infusible, a circumstance
which serves to distinguish leucite
from garnet and analcime ; when
mixed with borax it fuses into a
brownish diaphanous glass. Its
constituents are silex 53'75, alu-
mine 24*62, potash 21'35; specific
gravity from 2'45 to 2-49 ; hard-
ness = 5-5. It scratches glass

with difficulty. It occurs regularly
crystallized ; in granular concre-
tions, and in roundish grains. It
is often embedded in lava and in
basalt. All lavas do not contain
crystals of leucite. In the lava of
Vesuvius they are abundant, but in
that of Etna they are rarely found.

LEFCO'NIDA. An order of the class
poriphera, thus named from the
body being of a white colour, the
spicula of the skeleton being also
calcareous.

LEU'TTRITE. A mineral found in
Leuttra, in Saxony, and thus named
from that circumstance. Colour,
grayish-white, tinged in places
with an ochreous brown.

LI'AS. A provincial name, now be-
come conventional amongst geolo-
gists, for a kind of limestone, which,
with its associated beds, form a
particular group of the secondary
series. The name of lias has been
very generally adopted for a forma-
tion of argillaceous limestone,
marl, and clay, usually found in
comformable stratification to the
rocks of the oolite group. Mr.
Bake well considers that the name
lias was probably given to this for-
mation by the provincial pronunci-
ation of the word layers, as the
strata of lias limestone are generally
very regular and flat, and can easily
be raised in slabs from the quarry.
" The great bed of dark argillaceous
limestone, divided into thin strata,
called lias, is the best characterized
of all the secondary strata, (except
chalk) both by its mineral charac-
ters and the fossil remains imbedded
in it. The lias cannot be mistaken
for any of the lower strata; it
serves as a key to the geology of
the secondary formations in Eng-
land ; and the first enquiry which
the student should make, when he
is in doubt respecting the position
of any of the secondary beds, should
be, does it occur above or below the
lias *'

L I A

[ 256 ]

L I G

The upper portion of the deposits
constituting the lias, including
about two thirds of their total
depth, consists of beds of a deep
blue marl, containing only a few
irregular and rubbly limestone
beds. In the lower portion, the
limestone bedsincreasein frequency,
and assume the peculiar aspect
which characterises the lias, pre-
senting a series of thin stony beds,
separated by narrow argillaceous
partings ; so that quarries of this
rock at a distance assume a striped
and riband-like appearance: in the
lower beds of this limestone, the
argillaceous partings often become
very slight and almost disappear,
as may be seen in the lias tract of
South Wales: beds of blue marl,
with irregular calcareous masses,
generally separate these strata from
the red marl belonging to the ad-
jacent new red-sandstone forma-
tion. The blue lias, which contains
much iron, affords a strong lime,
distinguished by its property of
setting under water; the white
lias takes a high polish, and may
be employed for the purposes of
lithography.

The lias, which may be regarded
as the base of the oolitic system,
may be traced on the south-west
to Lyme Regis, in Dorsetshire, and
on the north-east to "Whitby, in
Yorkshire. Near the latter place,
it is more fully developed than in any
other part of the kingdom, and has
been divided by Prof. Phillips into
three parts.

The building stone obtained from
the lias is, in general, when first
taken from the quarry, dressed with
great ease, but on exposure to the
atmosphere it parts with the moist-
ture which it possessed when under-
ground, and becomes much harder.

The lias group is placed below
the oolite, and above the variega-
ted sandstone, in this country ; in
Prance and Germany, below the

oolite, and above the Muschelkalk.
It is in the lias that the petrified
ink-bags of Loligo have been found.
Proofs are not wanting of intervals
between the depositions of the
component strata of the lias. Gry-
phites are so abundant in it, that
in Prance it has obtained the name
•of Calcaire a Gryphites; and, in-
deed, the Gryphite appears peculiar
to, and characteristic of, the lias
formation.

LIA'SSIC. Belonging to the lias. The
remains of reptiles, those of sau-
rian s in particular, are very common
in the liassic rocks in certain parts
of England.

LI'BER. In botany, a layer on the
inner surface, or that which is
contiguous to the wood, or the
bark of trees ; the innermost layer
of the bark. The liber appears to
be formed from the cambium.

LI'CHENS. The third order of the
class Thalogens, in the vegetable
kingdom.

LIE'VEITE. An earth mineral, called
also Yenite ; Lievrite after Le Lie-
ore, and Yenite, in commemoration
of the battle of Jena. Lievrite is
of a brown, or brownish-black co-
lour, sometimes dull externally,
but the crystals are often brilliant,
and opaque ; it scratches glass, but
is scratched by adularia. It occurs
amorphous, acicular, and also crys-
tallized. Analysis, silex 29-278,
lime 13-779, alumine 0-614, black
oxide of manganese 1'587, water
1-268. Specific gravity 3-8. It
is found in Elba, and also in Sibe-
ria and Norway.

LI'GAMENT. (ligamentum, Lat. liga-
ment, Er. ligamento, It.) A strong,
flexible, tough, compact, membrane,
serving to keep together certain
parts.

"Nothing," says Dr. Eoget,
" can be more artificially contrived
than the interweaving of the fibres
of ligaments ; for they are not only
disposed, as in a rope, in bundles

L I G

[257]

L I L

placed side by side, and apparently
parallel, to each other; but, on
careful examination, they are found
to be tied together by oblique
fibres curiously interlaced in a way
that no art can imitate. It is only
after long maceration in water,
that this complicated and beautiful
structure can be unravelled."

In conchology, the membrana-
ceous substance which connects the
valves together; the true ligament
is always external.
LI'GNIN. } Lignin is deposited, du-
LI'GNINE. ) ring the growth of the
plant, with the intention of forming
a permanent part of the vegetable
structure, constituting the basis of
the woody fibre, and giving me-
chanical support and strength to
the whole fabric of the plant.
LI'GNITE. (from lignum, Lat.) Wood-
coal. Lignite is brown or black.
Some lignite has the appearance of
jet, is of a velvet-black, does not
soil the fingers, is very brittle, and
burns with a bright flame. Lignite
is a much more recent formation
than that of common coal. By
some, lignite is considered to be
an imperfect coal, as wood not yet
mineralized, or passed into a state
of coal ; while o thers doubt whether
lignite ever becomes true coal. Lig-
nite, like coal, is of vegetable origin,
but it differs in many respects from
common coal. There are several
varieties of lignite; these mostly
burn with flame, but they neither
swell nor cake like coal.

"Lignites," says Dr. Tire, "which
are manifestly bituminized wood,
hold an intermediate place in the
gradation between vegetable matter
and pit coal. They have the fibre
of the former, with the jetty lustre
and fracture of the latter. Some
lignites closely resemble peats in
their chemical characters; others
seem to graduate into perfect coal.
Lignite has generally a woody as-
pect; coal always that of a rock."

"I may remark," says Hugh
Miller, " that independently of
their well-marked organisms, there
is a simple test by which the lig-
nites of the newer formations may
be distinguished from the true coal
of the carboniferous system. Coal,
though ground into an impalpable
powder, retains its deep black color,
and may be used as a black pigment;
lignite, on the contrary, when fully
levigated, assumes a reddish, or
rather umbrey hue."

Lignite consists of carbon 69*3;
hydrogen 6-6; and oxygen and
nitrogen 25 '3.

LI'GIJLATE. | (from ligula, a strap,
LI'GULATED. j Lat.) Strap-shaped.
A term applied to the radical florets
of compound flowers, when shaped
like a strap or ribbon. The pro-
jecting parts of the limb of an
irregular corolla are called lips;
when one lip is very long and
narrow, compared to the length
of the tube, the corolla is called
ligulate, or strap-shaped.
LI'GTJBITE. (from liguria, Lat.) A
mineral of an apple-green colour,
occasionally speckled. It ranks as
a gem.
LI'LALITE. Another name for the

mineral lepidolite.

LILIA'CEOTJS. (liliacem, Lat.) Ee-
sembling a lily ; lily-like. A co-
rolla having six regular petals is
termed a liliaceous corolla.
LI'LY E'NCBZNITE. (The encrinites
moniliformis.) So called, because
the arms, when folded, resemble
the head of the lily. This is one
of the most beautiful of the fossil
crinno'idea, hitherto found only in
the muschelkalk of the new red
sandstone group. Mr. Parkinson
states that, independently of the
number of pieces which may be
contained in the vertebral column,
and which, from its probable length,
may be very numerous, the fossil
skeleton of the superior part of the
lily encrinite consists of at least

L L

L I L

[258]

L I M

twenty-six thousand six hundred
pieces. The body is supported by
a long vertebral column attached
to the ground by an enlargement of
its base. It is composed of many
cylindrical thick joints, articulating
firmly with each other, and having
a central aperture, like the spinal
canal in the vertebrae of aquadruped,
through which a small alimentary
cavity descends from the stomach
to the base of the column. Prom
one extremity of the vetebral column
to the other, and throughout the
hands and fingers, the surface of
each bone articulates with that
adjacent to it, with the most per-
fect regularity and nicety of ad-
justment. So exact and metho-
dical is this arrangement, even to
the extremity of its minutest ten-
tacula, that it is just as improbable,
that the metals which compose the
wheels of a chronometer should for
themselves have calculated and
arranged the form and number of
the teeth of each respective wheel,
and that these wheels should have
placed themselves in the precise
position, fitted to attain the end
resulting from the combined action
of them all, as for the successive
hundreds and thousands of little
bones that compose an encrinite,
to have arranged themselves, in a
position subordinate to the end
produced by the combined effect
of their united mechanism; each
acting its peculiar part in harmo-
nious subordination to the rest, and
all conjointly producing a result
which no single series of them
acting separately, could possibly
have effected. The pelvis of the
lily encrinite resembles in shape a
depressed vase, and, by some, it is
supposed that its upper part was
closed by an integument, in the
centre of which was placed the
mouth. The encrinite differs from
the pentacrinite in having its plates,
or vertebra, rounded, whereas in

the pentacrinites they are penta-
gonal.

LI'MA. (lima, Lat. a file.) A genus
of bivalve shells placed by Lamark
in the family Pectinides. The limse
are nearly equivalve, inequilateral,
compressed, oblique, and auricu-
lated, the anterior auricle being
smaller than the other ; the hinge
consists of a triangular disk sepa-
rating the umbones, divided in the
centre by a triangular ligamentary
pit without teeth; the anterior
border has an hiatus more or less
wide, a feature which, together
with the triangular disk and ob-
lique form, distinguishes them from
the pectens. The Limse are found
in the shallows among corals and at
small depths, they swim freely and
rapidly, or rather flutter through
the water, working the valves of
their shell like fins or paddles.
M. Deshayes in his tables records
13 species fossil in the tertiary for-
mations, other species occur in the
cretaceous and oolitic systems of
rocks; in the latter more especially,
the number of species exceeds that
recorded from the tertiary series.
Some species spin a byssus, others
are free. — Lycett.

LIMAX. (Umax, Lat. a snail.) The
cochlea terrestris, or snail, so called
from its sliminess.

LIMAX. The Latin name for those
air-breathing naked gasteropodous
mollusks, vernacularly known by
the name of slugs. Linneeus em-
ployed the term Umax as a generic
appellation for the naked slugs,
and thus defines them ; body ob-
long, repent, with a fleshy shield
above and a longitudinal flat disk
below. A dextral lateral foramen
for the genitals and excrements.
Pour tentacles above the mouth.

LIMB, (from limbus, Lat.)

1. An edge or border, as the sun's
limb, the moon's limb, &c.

2. An extremity of the body, as
the arm or leg.

L I M

[259 ]

LI M

3. In botany, the outer spreading
portion of a monopetalous corolla.

LI'MBILITE. (from Limbourg, in
Swabia.) A compact mineral of a
honey-yellow colour, supposed to
be a decomposed olivine. On ex-
posure to the action of the blow-
pipe, it fuses into a compact,
shining, black enamel.

LIME. The protoxide of calcium, one
hundred parts consisting of 72 of
calcium, its metallic basis, and
28 of oxygen. Lime does not exist
in a pure state in nature, it has so
strong an affinity for carbonic acid
as to absorb it from the atmosphere,
when it becomes converted into
carbonate of lime, constituting the
different kinds of marble, chalk,
and limestone, and forming exten-
sive strata, and the largest moun-
tain ranges. Lime is a white or
light grey earth, fusible only by
the heat of a galvanic battery, or
of a gas blow-pipe ; it is exceeding-
ly caustic, and if water be sprinkled
upon it, great heat is produced, the
water unites with the lime, forming
a hydrate of lime. Lime is
partially soluble in water, and
there is a singular circumstance
connected with this, namely, that
cold water dissolves a larger pro-
portion than hot water. Specific
gravity 2 '3.

LI'MESTONE. A genus of minerals
comprising many species. How-
ever various in external appear-
ance limestone may be, it is, if
pure, essentially composed of 57
parts of lime and 43 carbonic acid ;
but in some rocks the limestone is
intermixed with magnesia, alumine,
silex, or iron. The specific gravity
ef limestone varies from 2-50 to
2.80. All limestones may be scra-
ped with a knife. They are infu-
sible ; but when impure, by an in-
termixture with a portion of other
earths, they vitrify in burning.
All limestones effervesce when a
drop of strong acid is applied on

the surface ; and they dissolve
entirely in nitric or muriatic acid.
The specific gravity, hardness, and
effervescence with acids, taken
collectively, distinguish limestone
from all other minerals.

The whole of the limestone de-
posits have been arranged into the
following suite. In the inferior or
primary order, crystalline marbles ;
in the transition and carboniferous
orders, compact and sub-crystalline
limestones; in the secondary, less
compact limestone, calcareous free-
stone, and chalk; in the tertiary
or supracretaceous order, loose
earthy limestones.

Primary limestone has always a
granular structure ; but the size of
the grains is variable, and seems,
in some degree, to correspond with
the relative age of the mineral.
Thus the limestone, which occurs
in beds in gneiss, and which is
supposed to belong to the older
formations, has usually a coarse
texture, and large granular concre-
tions. But when its beds exist in
mica slate, or argillite, its texture
becomes more finely grained, and
its colour less uniform. Transition
limestone has a texture more or less
compact; its colours are much
variegated; and it often contains
petrifactions. Secondary limestone
has a compact texture, a dull frac-
ture, and usually contains shells,
and sometimes other organic re-
mains. It is always stratified;
bat the strata are sometimes in-
clined, sometimes horizontal.

Sir H. Be La Beche states the
quantity of lime in granite com-
posed of two-fifths quartz, two-
fifths felspar, and one-fifth mica, to
be 0-37 ; and in greenstone, com-
posed of equal parts of felspar and
hornblende, to be 7'29.
LIMN^J'A. j (from Tu/tj/as, a marsh, or
LIMNE'US. ) pool, Gr.) A genus of
fresh water univalves, placed by
Cuvier in the order Pulmonea, class

L I M

Gasteropoda ; and by Lamarck in
the family Limnacea. The Limnea
is an ovate-conical, or turretted
univalve, it has an oblong spire,
and the aperture higher than it is
wide ; it may be distinguished
from the lulini by the very oblique
fold on the columella. The Limnea
has been found fossil in the neigh-
bourhood of Paris. The recent
Limnea inhabits our lakes and
pools ; its shell is of a light amber
colour.

LIM'NITE. A fossil limnea.

LIM'OPSIS. The name assigned by
Sassi to a genus of bivalve conchi-
fera, belonging to the family
Arcacea.

LI'MULUS. The Molucca crab. A
genus of crustaceans, or entomos-
tracans, having a distinct carapace
or buckler, with two eyes in front
of the shield. The limulus appears
to approximate towards the trilo-
bite, and Buckland says, " the
history of this genus is important,
on account of its relations both to
the existing and extinct forms of
crustaceans ; it has been found
fossil in the coal formations of
Staffordshire and Derbyshire, and
in the Jurassic limestone of Aich-
stadt, near Pappenheim; a small
fossil species is found in the iron-
stone nodules of Coalbrook Dale.
Of the tail of the recent limulus,
savages form a point to their
arrows; and, when thus armed,
they are much dreaded. The eggs
of the limulus are eaten by the
Chinese.

LINE OF BEAMING. | Strata almost al-

LINE or DIP. j ways decline,
or dip down, to some point of the
horizon, and, of course, rise towards
the opposite point. A line drawn
through these points is called the
line of their dip. If a book be
raised in an inclined position, with
the back resting lengthwise upon
the table, the leaves may be sup-
posed to represent different strata,

[ 260 ] LIE

then a line descending from the
upper edges to the table, will be the
line of dip, and their direction
lengthwise will be their line of

LINES OF GBOWTH. In conchology,
those concentric lines or markings
in a shell, formed by successive
layers of shelly matter, which mark
its growth. The external layer is
always the most recent.

LINEAR, (linearis, Lat.)

1. In entomology, a figure having
the lateral margins very close
together, and parallel throughout.

2. In conchology, composed of
lines ; being marked with lines.

3. In botany, a term applied to
narrow leaves, when they are of
equal breadth throughout, the two
edges being straight, and equi-dis-
tant from each other.

LI'NEATE, (lineatus, Lat.) Marked
with lines; marked with longitu-
dinal depressions.

LI'NGULA. A genus of bivalve shells
composed of two valves, nearly
equal, truncated anteriorly; the
hinge having no teeth : the beak
of the valves pointed, and united
to a tendinous tube, serving for a
ligament ef attachment. This is
the only bivalve shell which is
pedunculated. The recent lingula
inhabits the Indian ocean ; it has
thin, horny, and greenish valves.
It is also found fossil in the Ludlow
limestone, and in the oolitic rocks
of Yorkshire.

LI'NGULATE. (lingulatm, Lat.)
Tongue-shaped ; an epithet for
leaves shaped like a tongue.

LIQTJEFA'CTION. (liquefactio, a melt-
ing, Lat. liquefaction, Fr. liquefa-
zi6ne, It.) The act of melting;
the state of being melted. This
word is sometimes used synony-
mously with fusion, sometimes
with deliquescence, and at others
with solution.

LI'BICONITE. (from \eipos, pale, and
sand or dust, Gr.) A name

LIT

261

LIT

given to arseniate of copper. It is
of a blue or green colour, and
occurs in copper mines.

LI'THIA. A new alkaline substance,
discovered by M. Arfwedson, a
Swedish cbemist, in 1818, in the
mineral called Petalite : in its ob-
vious properties, lithia approaches
to potassa and soda, but it posses-
ses a greater neutralizing power.
It has subsequently been obtained
from lepidolite, spodamene, and
some kinds of mica. It is composed
of lithium 56-50, and oxygen
43 '50. It received its name from
having been discovered in a stony
mineral.

L'ITHTTJM. The metallic base of
Lithia, discovered by Sir H. Davy.
This metal is obtained from lithia
by de-oxidising processes ; but if
placed in contact with the atmos-
phere, it returns to the state of
lithia too rapidly to admit of an
accurate examination.

LI'THOCAEP. (from \i'0o?, a stone,
and KapTros, fruit, Gr.) Petrified,
or fossil fruit.

LITHODE'NDRON. (from Xt0o?, a stone,
and Sevftpov, a tree, Gr.) A name
given to coral, from its likeness to
petrified wood.

LITHO'DOMTTS. (from \j0oe, a stone,
and Sefua, to build, Gr.) A
transverse, elongated, cylindrical,
marine equivalve. Affixed at first
by byssus to rocks, which it subse-
quently penetrates, and remains
ever after in the cavity. It is a
littoral shell, found at depths vary-
ing to ten fathoms. »

LITHO'GENOUS. (from X/<9o9, stone,
and fyej/i/aw, to produce, Gr.)
Belonging to the class of animals
which form coral.

LITHOI'DAL. (from \j0os, a stone,
and e?&>9, resemblance, Gr.) Ke-
sembling stone; of a stony struc-
ture.

LITHOLO GICAL. (from Xe!0o9, and
\oyiK09, Gr.) Eelating to the
science of stones ; in geology, a

term used to express the stony
character or structure of a mineral
mass.

LITHO'LOGY. (from \t0os, a stone,
and Xo'ryo?, discourse, Gr. lithologie,
Fr.) That branch of natural his-
tory which treats of stones. "By
lithology," says Prof. Jukes, "I
would mean the study of the in-
ternal structure, the mineralogical
composition, the texture, and other
characters of rocks, such as could
be determined in the closet by the
aid of hand specimens."

LI'THOMABGE. (Tho steinmark of
Werner : argile lithomarge of
Haiiy.) Called also stone-marrow ;
a variety of talc. It has commonly
a fine grain, of a white, gray,
yellow, red, or brown colour, these
colours being sometimes disposed
in spots, clouds, veins, or stripes ;
unctuous or greasy to the touch,
and adheres to the tongue. In
water it falls to powder, and does
not form a paste. Specific gravity
2-4. It is infusible before the
blow -pipe. It occurs massive,
disseminated, globular, and in ir-
regular lumps, in gneiss, porphyry,
serpentine, &c. Jameson divides
lithomarge into two sub-species,
friable lithomarge and indurated
lithomarge : the friable is charac-
terised by its scaly particles, soiling,
and low degree of coherence; the
indurated, by fracture, streak, soft-
ness, and sectility. The Chinese
are said to use it, when mixed
with the root of veratrum album,
instead of snuff.

LITHO'PHAGI. (from \i0os and <fra<yeiv,
to eat, Gr. lithophage, Fr.) Mol-
luscs which eat holes in stones and
rocks. While the lithodomi pene-
trates rocks by chemical action,
dissolving the stony matter, litho-
phagi mechanically perforate, or
bore into them. They belong to
Lamarck's family of Lithophagidae.

LITHOPHA'GID^. A family of tere-
brating bivalves.

LIT

[ 262 ]

LOB

LI'THOPHYTE. (from \i0os, a stone,
and 0vTov, a plant, Gr. Uthophyte, Fr)

1. A stony plant ; a coral.

2. The animal which secretes coral.
LITHO'BNIS. (from \iOos, a stone,

and opvi9f a bird, Gr.) The name
assigned by Prof. Owen to a sub-
genus of fossil birds of the vulture
kind, one species of which, Lithor-
nis Yulturinus, he has described.

LITHO'XYLE. (from \i'0osf stone, and
gv\ov, wood, Gr.) Silicified wood.

LITTO'BNIA. A genus of turbinated
univalve shells, they are thick,
have few whorls with a short spire,
the aperture is large, entire,
rounded anteriorly, the outer lip
thickened and the columella rather
excavated, the operculum is horny
and spiral ; this latter character
separates it from the Turbo. The
species are numerous, both recent
and fossil. — Lycett.

LI'TTJITE. A fossil shell found in the
transition limestone together with
the Orthoceratite. The lituite is a
chambered shell, partially coiled up
into a spiral form at its smaller
extremity, its larger end being
continued into a straight tube of
considerable length, separated by
transverse plates, outwardly con-
cave, and separated by a siphuncle.

LITTJ'OLA. A multilocular univalve ;
a genus of microscopic foraminifera,
partly spiral, the last turn being
straight at the end: found both
recent and fossil.

LI'ZARD. (lezard, Fr. lacertm. Lat.)
In Cuvier's arrangement the lizards
form the second genus of Lacerti-
nida. They are distinguished by
the tongue, which is thin, extensi-
ble, and terminating in two threads.
The extremity of the palate is
armed with two rows of teeth,
which are generally either recur-
vated or conical. Lizards have
usually a single perforated eye-lid,
which, when closed by its orbicular
muscle, exhibits merely a horizon-
tal slit. The body is naked, with

four feet and a tail ; and they
possess the property of reproducing
the tail should it be lost.
LLANDEI'LO FLAGS. The name given
to the lower member of the lower
Silurian rocks, forming the base of
the Silurian system. "They
have been named," says Sir R.
Murchison, "after the town of
Llandeilo, in Caermarthen shire,
where they are largely developed.
They consist of hard, dark-coloured
flags, sometimes slightly micaceous,
frequently calcareous, with veins
of white crystallised carbonate of
lime, and are especially distinguish-
ed by containing the large trilobites,
Asaphus Buchii and Asaphus ty-
rannus ; Agnostus M'Coyii, Tri-
nucleus fimbriatus, &c."
LOAM. (leTim, Germ.) An earthy
mixture, in which sand and clay
form large proportions : when the
compound contains much calca-
reous matter it is usually called
marl. Any soil which does not
cohere so strongly as clay, but
more strongly than chalk, is desig-
nated loam. Loam may be denned,
a soft and friable mixture of clay
and sand, enough of the latter
being present for the mass to be
permeable by water, and to have
no plasticity.

LO'BATE. \ 1. In entomology, when

LO'BATED. > the margin is divided

LO'BED. ) by deep undulating,

and successive incisions.

2. In botany, applied to leaves,

when the margins of the segments

are rounded; according to the

number of lobes, the leaf is termed

bilobate, trilobate, &c.

LOBE, (lolus, Lat. lole, Fr. lolo, It.)

1. A rounded portion of certain
bodies, as the lobes of the brain,
the lobe of the ear, the lobes of the
lungs, liver, &c.

2. In botany, the cotyledon of the
seed is also called the lobe.

LO'BULE. The diminutive of lobe;
a little lobe.

LOG

[263]

L 0 N

LOCOMO'TION. (from locus and motio,
Lat.) The power of moving at
will from one place to another ; of
transferring the whole body from
one place to another. The power
of locomotion constitutes the most
general and palpable feature of
distinction between animals and
vegetables. Excepting a few among
the lower order of creation, such
as molluscs and zoophytes, all
animals are gifted with the power
of spontaneously changing their
situation.

LOCTTLI'CTDAL. In botany, a par-
ticular kind of dehiscence. Some
fruits open by the dividing of each
carpellum at its midrib, so that
the dissepiments stick together,
and to two halves of contiguous
carpella; this is called loculicidal
dehiscence.

LODE. (a mining term.) A word
used to signify a regular vein or
course, whether metallic or not;
but most commonly it signifies a
metallic vein. When the substances
forming the lodes are reducible to
metal, the lodes are said to be
alive ; otherwise, they are termed
dead lobes.

Loess. (Germ.) A provincial German
term for an alluvial tertiary de-
posit of calcareous loam, occurring
in detached patches throughout
the valley of the Rhine. In Alsace
the loess is termed lekm. It
encloses freshwater and land shells,
as well as some mammiferous
remains. Sir C. Lyell observes,
"the loess is found reposing on
every rock, from the granite near
Heidelberg to the gravel of the
plains of the Rhine. It overlies
almost all the volcanic products,
even those which have the most
modern aspect; and it has filled
up, in part, the crater of the
Rodenberg, at the bottom of which
a well was sunk in 1833, through
seventy feet of loess.

LOLI'GO. (loligo, Lat.) A genus of

the family of Sepise. In the loligo
is found that peculiar provision for
defence, the ink-bag, a bladder-
shaped sac, containing a black and
viscid ink, the ejection of which,
by rendering the surrounding
water dark and opaque, defends
the animal from the attacks of its
enemies. In the lias of Lyme
Regis, ink-bags of the fossil loligo
are preserved, still distended, as
when they formed parts of the
organization of living bodies, and
retaining the same juxta-position
to an internal rudimentary shell
resembling a horny pen, which the
ink-bag of the existing loligo bears
to the pen within the body of that
animal.

LO'MONITE. Diatomous Geolite. So
named after its discoverer, Gillet
Laumont. See Laumonite.

LONCHO'PTERIS MANTE'LLI. A species
of fossil fern found in the shales
and clays of Tilgate Forest, and
thus named after Dr. Mantell. It
is characterised, by the distribution
of the nervures of the leaves.
This fern probably did not exceed
a few feet in height.

LONDON CLAY. (The name London
Clay has been assigned to this
great argillaceous formation from
the circumstance of its forming
the general substratum of London
and its vicinity, occurring imme-
diately beneath the vegetable soil,
excepting when occasional deposits
of alluvial, or diluvial, gravel, sand,
&c., intervene.) This formation
consists of a bluish or blackish
clay, including, in some localities,
beds of grey limestone and sand-
stone, lying immediately over the
plastic clay and sand, and is an
upper member of the arenaceous
and argillaceous formation that
covers the chalk. Its thickness is
very considerable, sometimes ex-
ceeding 700 feet. It contains lay-
ers of ovate, or flattish masses of
argillaceous, limestone. These

L 0

[ 264]

L 0 N

masses, called septaria, are some-
times continued through a thick-
ness of two hundred feet ; of these,
Parker's cement is made. The
septaria lie horizontally, and are
disposed at unequal distances from
each other in seemingly regular
layers. They frequently include
portions of wood pierced by tere-
dines, nautili, and other shells ;
and it is a curious fact that septa
of calcareous spar frequently inter-
sect the substances contained in
the septaria. These septaria were
at one time deemed characteristic
of the London Clay, but they have
been found in other formations,
more particularly in the upper
parts of the "Wealden. Sulphuret
of iron, phosphate of iron, and
selenite are found interspersed
throughout the London Clay ; on
which account the water issuing
from it is not fit for domestic pur-
poses. Amber and fossil copal or
resin have been found in this
deposit. From the London Clay
three or four hundred species of
testacea have been procured, but
the only bones of vertebrated
animals are those of reptiles and
fish. Remains of turtles have
been dug out of this deposit at
Highgate and Islington, and some
bones of a crocodile were discovered
by Mr. Parkinson ; nautilites also
are found in it. The shells of the
London clay mostly belong to gen-
era inhabiting our present seas.
The following is principally ex-
tracted from Conybeare and Phil-
lips's Geology of England and
Wales.

An idea of the nature and com-
position of the London Clay forma-
tion may be arrived at by the fol-
lowing section afforded by a well
sunk at Tottenham, in Middlessex.
1. Immediately below the sur-
face was found brick earth and
coarse yellow sand, stiff «lay,
and marl. 20

2. Blue clay of various inten-
sity of colour and degrees of
stiffness, adapted for tile-ma-
king. It effervesced slightly,
and enclosed hard and irregular
masses of a lighter colour, full
of minute appearances of char-
red vegetable matter, and sep-
taria, which also effervesced. 60

3. Blue clay of a greasy aspect
and somewhat greasy to the
touch ; it did not effervesce. 20

4. Purple, blue, red and brown
clay mixed, having greatly the
appearance of some varieties of
lithomarge; it did not effer-
vesce. 10

5. Blue, white, and brown clay
mixed, much heavier than the
preceding : it contained very
compact, hard, and nearly
cylindrical masses, six to
twelve inches long, and of a
yellowish- white colour : it effer-
vesced strongly. 10

6. Yellowish white clay, fre-
quently compact and hard, and
equally heavy with the prece-
ding : it effervesced strongly. 3

7. Rock bored through. 2

Feet, 125

There are very few genera of
recent shells which have not some
representative imbedded in this
formation, but the specific charac-
ter is usually different; on the other
hand but few of the extinct genera,
so common in the older formations,
occur in this, so that it seems to
hold a middle character in this
respect between the earlier and
more recent beds. Thus though
nautilites resembling those of the
Indian seas are common, specimens
of the cornu ammonis and the
belemnite are so rare, that it is
very doubtful whether they have
ever been found. Echinites, so
common in the chalk, are very rare
in this formation.

The most interesting facts con-

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nected with the vegetable remains
found in the London clay, are
those which have been observed in
the Isle of Sheppey : the quantity
of fruit or ligneous seed vessels is
extraordinary. Mr. Crowe, of
Faversham, has procured from this
productive situation a very large
collection, from which he has
selected 700 specimens, none of
which are duplicates, and very few
of which agree with any known
seed-vessels. Among these are
many which appear to belong to
tropical climates. Mr. Bowerbank
observes, " among the numerous
and highly interesting fossils found
in the London clay, none are more
abundant than the remains of fruits
and seeds." He also states that
during a few years 120,000 fruits
and seeds have passed through his
hands. In these beautiful remains
of an extinct flora, the minute and
delicately formed vegetable tissues
are preserved in the most perfect
manner. As regards the extent of
the London clay deposit, it forms
the superior stratum of the chalk
basin of London, except where it is
partially covered by the sands of
the upper marine formation, or by
alluvial sands, gravel, and loam.
It extends uninterruptedly and in
a south-westerly direction from
Orford, on the coast of Suffolk,
about 20 miles north-east of Har-
wich, and a little to the north of
Ipswich, in that county ; to the
south of Coggeshall, and thence to
Eoydon, in Essex ; from this place
it turns nearly south, extending to
a little on the west of Edmonton,
in Middlesex, and thence in a
north-westerly direction by Chip-
ping Barnet and South Mims to the
north of Eidge Hill ; here it turns
suddenly southward, and afterwards
south-west by Harfield and Ux-
bridge to the eastward of Colebrook ;
it then passes away nearly west,
crosses the Thames by Windsor

and Twyford, and passes to about
three miles south-west of Beading,
which is its most western point.
It then turns to the south-east, in
an irregular line, to within a very
short distance of Farnham and
Guildford, in Surrey, and on by
Epsom, and a little to the north of
Croydon to Deptford, in Kent.
The London clay, therefore, con-
stitutes a very large part of the
soil of Suffolk, nearly the whole of
Essex, quite to the sea, the whole
of Middlesex, and portions of Berk-
shire, Surrey, and Kent. In this
last county it shows itself on the
northern side of the Medway; it
constitutes the whole of the Isle of
Sheppy, rapidly disappearing under
the force of the waves, the cliff
from Whitstable to Reculver, and
extends nearly to Canterbury, and
thence to Boughton Hill. In the
chalk basin of Hampshire this
deposit is also extensively devel-
oped, forming the whole line of
coast from Worthing in Sussex to
Christchurch in Hampshire, ex-
tending thence inland by Eing-
wood, Eomsey, Fareham, and to
the southward of Chichester to
Worthing. It is found also in the
Isle of Wight, thrown with the
subjacent chalk into a nearly verti-
cal position. With this exception,
the beds of the London clay are
nearly horizontal.

It has been remarked, that if
the description of the Paris rocks
had not preceded that of the coun-
try round London and of the Isle
of Wight, it never would have been
considered that the Plastic clay was
separated from the London clay,
but rather that they constituted
different terms of the same series.
The London clay belongs to the
eocene period.

LONGICO'BNES. (from longus and cornu,
Lat. long horned.) A family of
insects in Cuvier's arrangement,
and so named from the length of

1C 1C

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their antennae, which are filiform
and cetaceous, and usually as long,
often longer, than the body of the
insect.

LONGIP'ENNES. (from longus an&penna,
Lat. long wings.) A family of
birds in Cuvier's arrangement, in-
cluding those birds, which, from
the great strength of their wings,
whence they derive their name,
are to be met with in all latitudes :
the bill, in some genera is hooked
at the end, in others simply pointed.

LONGIEO'STEES. (from longus and ros-
trum, a beak, or bill, Lat.) A
family of birds comprising the
waders, or birds with long bills.

LO'NGITTTDE. (longitudo, Lat. longitude,
Fr. longitudine, It.) The distance
of any part of the earth to the east
or west of any place. The meridian
passing through the observatory at
Greenwich is assumed by the British
as a fixed origin, whence ter-
restrial longitudes are measured.
As each point on the surface of the
earth passes through 360°, or a
complete circle, in twenty -four
hours, at the rate of 15° in a hour,
time becomes a representative of
angular motion. Hence, if the
eclipse of a satellite happens at
any place at eight o'clock in the
evening, and the nautical almanack
shows that the same phenomenon
will take place at Greenwich at
nine, the place of observation will
be 15° of west longitude. In the
case of stations differing only in
latitude, the same star comes to
the meridian at the same time, but
at different altitudes. In that of
stations differing only in longitude,
it comes to the meridian at the
same altitude, but at different times.
Supposing, then, that an observer
is in possession of any means by
which he can certainly ascertain
the time of a known star's transit
across his meridian, he knows his
longitude; or if he knows the
difference between its time of

transit across his meridian and
across that of any other station, he
knows the difference of longitudes
between those two places.

LOPHI'ODON. (from Xo0«s and oSov?,
Gr.) A fossil genus of mammalia,
now entirely extinct, allied to the
tapir, rhinoceros, and hippopotamus,
and connected with the Anoplo-
therium, and Pala3otherium ; so
named from certain points, or
eminences, on the teeth. Although
this genus is not widely removed
from the tapirs, Cuvier thought it
desirable to separate it. Like the
tapirs the Lophiodon has six in-
cisors and two canines in each jaw.

LOWEE CHALK. The chalk formation
or series is generally divided into
six distinct members, namely, the
lower green- sand ; the gault ; the
upper green -sand ; the chalk without
flints, or the lower chalk; the chalk
with flints, or the upper chalk, and
the Maestricht beds. This arrange-
ment is, however, altered by some
writers, inasmuch as a more minute
subdivision of some of the members
is concerned, depending on local
appearances. Generally speaking,
the lower chalk may be distinguished
from the upper by the absence of
flints, and by the superior hardness
of the chalk, which is sometimes
used for building-stone. The lower
is regularly stratified. In the north
of England, Professor Phillips
states, " The lower chalk is of a red
colour, and flints are found in it.
The only mineral found in the
lower chalk is sulphuret of iron.
The fossil remains are very numer-
ous aud all of them marine."

LOWEE SILUEIAN ROCKS. In this di-
vision of the Silurian rocks, Sir E.
Murchison places the Caradoc sand-
stones and the Llandeilo flags ; these
are described under their particular
names.

LOWEE NEW RED SANDSTONE. (The
Rothe-todte-liegende of the Ger-
mans ; the Gres des Yosges— cou-

LOW

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L TJ D

ches inferieures, of the French.
The lowest subdivision of the New
Bed System. For a description
see Rothe-todte-liegende. It being
now fully proved by Sir R. Mur-
chison that the lower new red
sandstone graduates into the coal-
measures, a practical acquaintance
with this division of the new red
system becomes a matter of great
national importance. The maxi-
mum thickness of the lower new
red sandstone hitherto observed is
1000 feet; this formation is inter-
polated between the magnesian
limestone and the coal-measures.

LOWER OLD RED SANDSTONE. This
formation found in Scotland is the
representative of the Tilestone of
the Old lied System of England,
but in extent of vertical develop-
ment it far exceeds it. The tile-
stones compose the least of the
three divisions in England; their
representative in Scotland forms
by much the greatest of the three.
— Hugh Miller.

LOWER LUDLOW ROCK. The name
given to the third or lowest sub-
division of the Ludlow formation.
The strata of the lower differ from
those of the upper Ludlow rock in
being more argillaceous, less sandy
and calcareous, with rarely a trace
of mica. They constitute, in fact,
says Sir R. Murchison, a great
argillaceous mass strictly entitled
to the provincial name of mudstone.
The organic remains of the lower
Ludlow rock are upon the whole
very different from those of the
upper, as well as the Aymestry
limestone : for although some spe-
cies of shell are common to the
whole formation, the lower Ludlow
rock is characterized by many pe-
culiar remains, including two new
genera which have not been ob-
served in any overlying stratum;
namely, the conchifer Cardiola, and
the chambered shell Phragmoceras.
These, with the Orthoceras filosum

and Orthoceras pyriforme ; the Li-
tuites giganteus, and the Grapto-
lites Ludensis, are peculiar and
distinguishing fossils.

LO'ZENGED. In entomology, of a
quadrangular shape, with two op-
posite angles acute, and two obtuse.

LTTCERNAHO'IDA. The first order of
the class Hydrozoa, comprising
sertularia, and similar zoophytes.

LTTCI'NA. A genus of equivalve bivalve
shells belonging to the Nymphacea
of Lamark. They are orbicular,
flattened, andradiately striated; the
hinge has usually two small cardi-
nal teeth, and two lateral teeth on
each side of the umbo in one valve,
and one in the other; the ligament
is external, which distinguishes it
from Amphidesma. The species
are numerous, both living and
fossil, more especially the latter.

LTTCTT'LLITE. (from Lucius Lucullus,
a celebrated Roman, who is said
greatly to have admired it.) A
black variety of transition lime-
stone, a black marble.

LTJDLOW FORMATION. ) The term has

LUDLOW ROCKS. j been selected

because the town of Ludlow is built
upon the upper beds. The Ludlow
rocks form one of the four divisions
of the Silurian system, and have
been sub-divided into the Upper
Ludlow rocks, the Aymestry lime-
stone, and the Lower Ludlow rocks.
They consist of beds of sandstone,
shale and limestone. The upper
Ludlow rocks of slightly micaceous,
gray-coloured, thin-bedded sand-
stone: the Aymestry limestone of
sub-crystalline grey or blue argil-
laceous limestone ; the lower Lud-
low rocks of sandy, liver and dark
coloured shale and flag, with con-
cretions of earthy limestone. These
rocks are developed principally in
Shropshire, Herefordshire, Wor-
cestershire, Staffordshire, and Glou-
cestershire, in England, and in Rad-
norshire, Brecknockshire, Montgo-
meryshire, Glamorganshire, and

L U

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Caermarthenshire, in Wales. Or-
ganic remains are found in all
three sub-divisions. The Ludlow
formation, says Sir E. Murchison, is
the key which accurately reveals
to us the relations of the inferior
masses to the overlying strata.

LUXATED. j (lunatus, Lat.) Cres-

LI/NULATED. ) cent-shaped ; formed
like a half-moon.

LTJ'NTJLE. In conchology, a crescent-
like mark or spot, situated near
the anterior and posterior slopes in
bivalve shells.

LU'NULET. In entomology, a half-
moon shaped spot in insects, of a
different colour from the rest of the
body.

LUNTTLI'TES. A genus of foraminated
polypifers. A free, stony, circular
polypifer, with one side convex,
the other concave. The convex
side striated in rays, with intersti-
cial pores; the concave side radiated
with diverging rugae and grooves.

LU'STBE. In mineralogy, one of the
physical characters by which mi-
nerals may be recognized. It is
of several kinds, as metallic and
pseudo-metallic,adamantine,pearly,
silky, resinons, vitreous, waxy, &c.
In the absence of lustre, a mineral
is said to be dull.

LTTTRA'EIA. A genus of bivalves,
placed by Lamarck in the family
Mactracea. A thin, transverse,
inequilateral shell, gaping at the
extremities; two oblique and di-
verging hinge-teeth accompanying
a large pit for the cartilage. No
lateral teeth, in which feature it
differs from Mactra.
LYCOPODIA'CEJG. The first order of the
class Anogens. The club-mosses;
or club-moss tribe. Plants of an
inferior degree of organization to
conifera3, some of which they greatly
resemble in their foliage. This tribe,
at the present day, contains no
species more than three feet high,
while many of the fossil species are
as large as recent coniferse, having

attained to the size of forest trees.
The affinities of existing lycopodiacea
are intermediate between ferns and
conifera3 on the one hand, and ferns
and mosses on the other. They are
related to ferns in the want of sexual
apparatus, and in the abundance of
annular ducts contained in their
axis ; to conifers in the aspect of
their stems ; and to mosses in their
general appearance. The leaves of
existing lycopodiacea are simple,
and arranged in spiral lines around
the stem, and impress on the surface
scars of rhomboidal, or lanceolate
form, marked with prints of the
insertion of vessels.
LYCOPODI'TES. 1. Fossil plants of the
genus Lycopodium.
2. A genus of plants of the club-
moss tribe.

LY'DIAN STONE. The Lydischer-stein
of Werner; La pierre de Lydie
of Brochant ; Basanite of Kirwan ;
Lydian stone of Jameson. A variety
of siliceous slate ; a black siliceous
flint-slate, called by some black
jasper. It differs but little from
the common variety of siliceous
slate. Colour grayish or bluish-
black, sometimes quite black. Prof.
Jameson constitutes Lydian stone a
sub-species of flinty- slate. Specific
gravity from 2 -5 8 to 2 -62. It is
employed as a test or touchstone to
determine the purity of gold and
silver, whence its name Basanite,
given to it by Kirwan, from fidaa-
i/o?, Gr. the trier. It obtained its
present name from having been first
noticed in Lydia. It is described
by Pliny and Theophrastes.
LYMPH, (lympha, Lat. water.) A
colourless liquid, found in the lym-
phatics.

LYMPH OF PLANTS. During the vege-
tation of plants, there is a juice
continually ascending from their
roots. This is called the sap, or
lym/ph of plants. From experiments
made by Yauquelin, it was ascer-
tained that the lymph of the com-

L Y At

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MAC

mon elm consisted as follows :— Of
1039 parts, 1027'904 water and
volatile matter, 9-240 acetite of
potash, 1-060 vegetable matter,
0-796 carbonate of lime.
LYMPHA'TICS. Minute vessels per-
vading every part of tbe body,
absorbing and conveying the ab-
sorbed matter into the thoracic
duct, to be afterwards conveyed

into the blood. The lymphatics
are supplied within with valves,
and without with glands.
LY'EATE. (from lyra, a harp, Lat.)
Lyre-shaped; a term applied to
leaves divided transversely into
several segments, the segments
gradually increasing in size as they
approach the extremity of the
leaf.

M

MAC'ACUS. The fossil monkey, of
which two species are described by
Professor Owen, namely, M.
Eocoenus, and M. Rhesus. " Cuvier
says, our great comparative anato-
mist had met with no evidence of
any species more highly organized
than a bear or a bat, in the fossili-
ferous strata which formed the
theatre of animal life anterior to
the record of the human race. I
have been so fortunate, in my re-
searches of the fossil mammalia of
Great Britain, as to determine not
only the remains of extinct pachy-
dermal animals (Lophiodon and
Hyracotherium) in the Eocene
beds called the London clay, but,
likewise of a Quadrumane, or mon-
key, in a sandy stratum of the
same formation."

MACHAI'HODUS. The name assigned
by Dr. Kaup to an extinct genus
of carnivorous mammalia, distin-
guished by their falciform teeth,
and found in the newer tertiary
deposits of Italy, Germany, France,
and Great Britain. Prof. Owen, in
describing one species, the M. La-
tidens, says, it was a feline animal
as large as the tiger, and, to judge
by its instruments of destruction,
of great ferocity. The canines
curved backwards, in form like a
pruning knife, having the greater
part of the compressed crown pro-

vided with a double-cutting edge of
serrated enamel ; that on the con-
cave margin being continued to the
base ; the convex margin becoming
thicker there, like the back of a
knife, to give strength. Thus each
movement of the jaw with a tooth
thus formed, combined the power
of the knife and saw.

MACHAI'KODTTS. An extinct animal
of the order Mammalia, referrible
to the Miocene period, and allied
to the bear.

MACI'GNO. The Italian word for a
kind of stone, a siliceous sandstone
sometimes containing calcareous
grains, &c. Macigna pietra, a very
hard stone ; an eocene rock of
Italy.

MA'CLE. The Hohl spath of Werner ;
Hollow spar of Jameson. Made
occurs only in crystals, the form of
which is a four-sided prism. But
each crystal, when viewed at its
extremities, or on a transverse sec-
tion, is obviously composed of two
very different substances ; and its
general appearance is that of a
black prism, passing longitudinally
through the axis of another prism,
which is whitish. These crystals,
often long, are sometimes very
minute; in some instances their
edges are rounded. The crystals
of Made present a considerable
number of natural joints, which

MAC

[270]

MAC

lead to an octohedron for their
primitive form. Made scratches
glass ; its powder is soft and unc-
tuous. It is opaque, or sometimes
translucent. Colour, white or gray,
often shaded with yellow, green, or
red. Specific gravity 2*94. It is
found, generally, imbedded in
black argillaceous slate.

MACLT/EEA. A genus of fossils of the
Silurian formation.

MACLU'EEITE. Called also Brucite
and Chondrodite. A mineral occur-
ring in imbedded grains in small
massive pieces, and in longish
granular concretions. Colours yel-
low, straw-colour, orange, red, and
brown ; translucent ; scratches
glass ; fracture imperfectly con-
choidal. Specific gravity 3-15 to
3*50. It consists of magnesia 54*0,
silica 36-60, fluoric acid 4-0, oxide
of iron 2*30, potash 2-0, manganese
a trace.

MACEOPO'MA. The name given by M.
Agassiz to a genus of sauroid fishes,
the fossil remains of which have
been discovered in the chalk for-
mation. The scales of the Macro-
poma are studded with hollow
tubes, through which, it is stated,
there flowed a fluid which served
to lubricate the surface of the
body.

MACEODA'CTYLTJS. (from fuucpo?, long,
and ^aKTvXos, finger, Gr.) The
name given to a family of birds in
Cuvier's arrangement, having very
long toes. The coot, rail, &c., are
examples.

MA'CEODON. (Lycett.} Figure resem-
bling Byosoarca, with a similar
aperture in the lower border;
several teeth placed at the anterior
extremity of the hinge plate are
parallel and directed obliquely
downwards and backwards ; one or
two elongated teeth or plaits,
occupy the length of the hinge
plates. Macrodon Hirsonensis oc-
curs in the great and inferior oolite
of the Cotteswolds.

MACEOSPO'NDYLTJS. A fossil saurian
found in the oolite and lias forma-
tions.

MACEOSTO'MATA. (from /ta/^os, long,
and <7To/ta, mouth, Gr.) A family
of univalves, belonging to the order
Trachellipoda, comprising the gen-
era Stomata, Stomatella, and
Haliotis.

MACEOT/EA. (from [icucos, long, and
ovpa, a tail.) A family of crus-
taceans, including the lobster,
prawn, shrimp, &c. They are so
named from their having a long
tail, which is, at least, as long as
the body, and provided at its termi-
nation with appendages which
most frequently form a fin on each
side. This tail is always com-
posed of seven distinct segments.
Fossil genera of the family Ma-
croura have been found in the
Muschelkalk and in the lias.

MA'CTEA. (/xaKT/>a, Gr. mactra, Lat.
a kneading-trough.) A genus of
equivalve, inequilateral, transverse
bivalves, slightly gaping at the
extremities; the hinge, or middle
tooth, complicated ; lateral teeth
rather remote, compressed, and in-
serted. Shells of this genus have
only been found to inhabit the
ocean, at depths varying from ten
to twelve fathoms, in sands and
sandy mud. The French natural-
ists divide Mactra into two genera,
Mactra and Lutraria. In Turton's
Linne twenty- seven species are de-
scribed ; twelve are inhabitants of
our seas. The fossil species belong
to the tertiary formations.

MACTEOMY'A. A genus of fossil
bivalve shells found in the Jurassic
rocks, they are equivalve, rather
globose and rugose ; the hinge is
without teeth, on the posterior
side of the umbo is an hiatus
surrounded by a thickened laminal
plate to support the ligament. Qne
species occurs in the Lias, two in
the Inferior and Great Oolite in
England.— Lycett.

MAD

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MAG

MA'DKEPOEE. (madrepore, Fr. corps
marin pierreuX) qui resemble a des
rameaux, d une vegetation.) "A
stony polypifer, fixed, subden-
droidal, ramified ; the surface fur-
nished on every part with project-
ing, muricated cells : the interstices
porous. The cells scattered, dis-
tinct, cylindrical, tubular, and
prominent, hardly any stella ; the
lamellae of the internal parietes
very narrow." — Parkinson. In a
living state, the stony matter is
covered with a skin of living gela-
tinous matter, fringed with little
bunches of tentacula ; these are the
polypi: the skin and the polypi
contract on the slightest touch.
Madrepores are sometimes united
and sometimes detached ; where
the lamina take a serpentine di-
rection they are called meandrina,
or brain-stone.

The term Madrepore is generally
applied to all those corals which
have superficial star-shaped cavities.
Madrepores raise up walls and
reefs of coral rocks with aston-
ishing rapidity, in tropical cli-
mates.

MA'DBE'POEITE.

1. Fossil madrepore.

2. A variety of limestone, found
in large rounded fragments, com-
posed of numerous, small prisms,
nearly cylindrical. Opaque; surface
dark brown; fracture conchoidal
and black. Constituent parts, car-
bonate of lime 63, silex 13, alu-
mine 10, oxide of iron 11.

MAE'STRICHT BEDS. The name given
to the uppermost member of the
cretaceous group, from Maestricht,
a town of the Netherlands. The
Maestricht beds are marine, and com-
posed of a soft yellowish-white lime-
stone, resembling chalk, and con-
taining siliceous masses, ammonites,
hamites, hippurites, baculites, &c.
The siliceous masses found in these
beds are not composed of black
flint, but of chert and calcedony.

The Maestricht beds repose on the
upper chalk with flints. Similar
beds occur also at Faxoe, in
Denmark. Some of the fossils are
cretaceous, but none are tertiary.
Deshayes has been unable to
identify any of the shells of the
Maestricht beds with those of
the tertiary deposites.

M'AGAS. A genus of Brachipodous
shells. They are equilateral, in-
equivalve, one valve convex with
a triangular area, divided by an
angular sinus in the centre. The
other valve flat, with a straight
hinge line and two small projections,
a partial longitudinal septum with
appendages attached to the hinge
within. Two species are recorded
from the chalk of Norfolk. —
Lycett.

MA'GILTJS. A genus of univalve shells
belonging to the family Cricosto-
mata, according to the arrangement
of De Blainville, and to the order
Tubulibranchiata of Cuvier. The
shell is thick, tubular, and irregu-
larly contorted, having a longitudi-
nally carinated tube, at first regu-
larly spiral, and then extending
itself in a line more or less straight.
The young of the genus Magilus
has a very thin shell of a crystal-
line texture, but, when it has
attained its full size, and has
formed for itself a lodgment in
a coral, it fills up the cavity of
the shell with a glassy deposite,
leaving only a small conical space
for its body ; it continues to accu-
mulate layers of this material, so
as to maintain its body at a level
with the top of the coral to which
it is attached, until the original
shell is quite buried in this vitreous
substance. — Eoget. Cuvier. Sow-
erly.

MAGNESIA, (magnesie, Fr.) An earth
with a metallic basis called magne-
sium. Magnesia consists of mag-
nesium 61-4, oxygen, 38-6. Mag-
nesia is rarely found pure in a na-

MAG

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MAG

tive state. It enters into the compo-
sition of some of the primary rocks,
to which it usually imparts a sap-
onaceous feel, producing also a
striated texture, and frequently a
greenish shade. Magnesia first
became known ahout the begin-
ning of the eighteenth century.
Little, however, was known con-
cerning its nature, till Dr. Black
published his celebrated experi-
ments on it 1755. Magnesia may
be thus prepared : sulphate of
magnesia, a salt, composed of mag-
nesia and sulphuric acid, is to be
dissolved in water, and half its
weight of potass added. The potass
having a stronger affinity for the
sulphuric acid than the magnesia
has, seizes the sulphuric acid, and
the magnesia is precipitated. Mag-
nesia is often present in chalk;
some of the strata in Prance are
said to contain ten per cent, of
magnesia. Magnesia is present
in all the inferior stratified rocks,
with the exception of quartz rock,
(without mica,) and certain eurites,
or compact felspars. In the de-
trital rocks it is also common,
particularly when mica forms any
considerable portion of them.
There are few limestones which do
not contain magnesia. It is an
essential ingredient of dolomite,
carbonate of magnesia constitutes
more than 40 per cent, of that
rock. Magnesia is also dissemi-
nated through the waters of the
ocean, muriate of magnesia form-
ing from -004 to -005 of their
mass.

MAGNE'SIA MICA. Called also Biotite.
See Biotite.

MAG^E'SIAN LI'MESTONE. (The Zech-
stein of the German, the Calcaire
Alpin of the French geologists.)
The Magnesian limestone, though
somewhat extensively deposited in
England and Germany, appears but
little known in France. A marine
deposit, belonging to the new red

sandstone group. It lies above the
red conglomerate and below the
variegated sandstone. It is com-
posed of carbonate of magnesia, the
proportion of the latter amounting
to nearly one half in some instances.
It effervesces much more slowly
and feebly with sulphuric, nitric,
or muriatic acids than does the
common limestone. The magnesian
limestone of this country is a
dolomite of a yellow or yellowish-
brown colour ; it is distinctly
stratified, the strata varying from
a few inches to several feet in
thickness. This deposit is fossili-
ferous, and certain shells, products,
appear for the first time in the
magnesian limestone. Magnesian
limestone forms the most durable
building-stone, and it is of this that
the two new houses of parliament
are built. It is to be lamented
that Waterloo Bridge was not built
of magnesian limestone instead of
felspathic granite, a very perishable
kind of stone. Where the mag-
nesia is in excess the land is sterile,
but when it is not in excess, the
soil is fruitful, and, as a subsoil,
healthful.

MA'GNESITE. A mineral of a white
or yellowish-white colour. It
occurs massive, tuberose, reniform,
and versicular : fracture is con-
choidal : opaque : sp. gr. 2 '881 :
infusible, and before the blow-pipe
becomes so hard as to scratch glass.
It is composed of one equivalent of
carbonic acid and one of mag-
nesia.

MAGNE'SIUM. The metallic basis of
magnesia.

MAGNETIC IEOJT QBE. The Fer oxy-
dule of Haiiy ; Magnet eisenstein
of Werner. A black ore, possess-
ing a slight metallic lustre. Occurs
regularly crystallized; in granular
concretions ; massive and dissemi-
nated. It is magnetic, sometimes
sufficiently so to take up a needle.
It occurs in beds in primary and

MAG

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M A L

transition rocks. This ore is very
common in Sweden.

MA'GNETISM. (magnttisme, Fr.) The
tendency of the iron towards the
magnet, and the power of the
magnet to produce that tendency ;
the power of attraction. Very
delicate experiments have shewn
that all bodies are more or less
susceptible of magnetism. Many
of the gems give signs of it ; tita-
nium and nickel always possess
the properties of attraction and
repulsion. But the magnetic agen-
cy is most powerfully developed in
iron, and in that particular ore of
iron called the loadstone, which
consists of the protoxide and per-
oxide of iron, together with small
portions of alumina and silica. A
metal is often susceptible of magne-
tism if it contain only the 130,000th
part of its weight of iron, a quantity
too small to be detected by any
chemical test. One of the most
distinguishing tests of magnetism is
polarity, or the property a magnet
possesses when freely suspended, of
spontaneously pointing nearly north
and south, and always returning to
that position when disturbed. In-
duction is the power which a mag-
net possesses of exciting temporary
or permanent magnetism in such
bodies in its vicinity as are capable
of receiving it. By this property
the mere approach of a magnet
renders iron or steel magnetic, the
more powerfully the less the dis-
tance. Iron acquires magnetism
more rapidly than steel, yet it loses
it as quickly on the removal of the
magnet, whereas the steel is im-
pressed with a lasting polarity.

MAJO'LICA. A local name for a variety
of white compact limestone.

MA'LACHITE. (malachite, Fr malachite,
It.) Green carbonate of copper.

M'ALACOLITE. A variety of augite, of
a darkish green colour.

MAXACOPTE'EYGII. (from /iaXa/co?,
soft, and Tnepov, a wing or fin, Gr.)

One of the two great orders into
which Cuvier divided all bony
fishes. The rays of the fins are thin,
flexible, articulated, and branched;
each ray somewhat resembles a
jointed bamboo, with this difference,
that what veins a single ray at
bottom, branches out into three or
four rays atop. The gold-fish
serves as a familiar illustration of
this order.

MALACOPTE'BYGIONS. Soft finned ;
belonging to the order Malacop-
terygii.

MALACO'STRACAN". An order of Crus-
taceans, distinguished by having
sessile eyes, imbedded in the
substance of the head.

MALACTI'NIA. The name of a class of
animals belonging to the order
Cyclo-neura or radiata. These are
soft, free, aquatic animals, of a
simple structure, entirely marine,
generally of a transparent gela-
tinous texture, and radiated struc-
ture or form, luminous, and
emitting an acrid secretion from
their surface, which is capable of
irritating and inflaming the human
skin like the sting of a nettle.

MALLEABILITY. (malleabiliU, Fr.)
The property or capability of being
hammered into different forms with-
out breaking.

MA'LLEABLE. (malleable, Fr. malled-
lile, It.) That may be spread out
by hammering. Of all the metals,
the most malleable is gold, five
grains of which may be hammered
out so as to cover a surface of 273
square inches, the thickness of the
leaf not exceeding 282020^- of an inch.

MA'LLEUS. (malleus, Lat. a hammer.)

1. One of the bones of the ear,
' thus named from its supposed re-
semblance to a hammer.

2. A bivalve shell of the family
Malleacea.

MALM KOCK. The name given to a
variety of firestone, a member of
the chalk series.

MA'LTHA. A variety of bitumen j

N N

MAM

[274]

MAM

called also mineral pitch, from its
resemblance to pitch. Colour black
or dark brown. Specific gravity
from 1-45 to 2-07.

MA'MMA. (mamma, Lat.) The breast.

MA'MMAL. An animal belonging to
the class mammalia.

MAMMA'LIA. (from mamma, Lat. the
breast.) The highest class of ani-
mals is that which comprehends
man, and animals, which, like
man, possess a viviparous mode of
generation. The class mammalia
is divided by some authors on
natural history into two principal
sections, namely, Placentalia and
Marsupialia, or Implacentalia.
These animals have a heart con-
sisting of four cavities, two auricles
and two ventricles ; they have hot
and red blood. Their most essen-
tial character is that of their being
viviparous, and suckling their
young on milk, secreted in mam-
mary glands, which open by ducts
or teats, and they are thence called
Mammalia. The mammalia are
placed at the head of the animal
kingdom, not only because it is the
class to which man himself belongs,
but also because it is that which
enjoys the most numerous faculties,
the most delicate sensations, the
most varied powers of motion, and
in which all the different qualities
seem combined in order to produce
a more perfect degree of intelligence
— the one most fertile in resources,
most susceptible of perfection, and
least the slave of instinct. The
muscular system and the living
movements of mammalia are more
varied than in any other vertebrated
class, for some are organized to
plough the deep, or to clamber on
the rocky coasts ; some to burrow
in the e'arth, or to bound over the
plains; some to gambol on lofty
trees or cliffs, or to wing their way
through the air, and these different
conditions affect more especially the
organs of motion. The bones of

all the mammalia are nearly of the
same colour and general appearance
as those of man ; they are covered
with a periosteum, and contain
marrow, which in the whale tribe
is fluid. The skeleton of mammalia
is divided into head, trunk, and ex-
tremities. Next to man, the ape
tribe is found to have the largest
skull in proportion to the face, but,
even in the ape, it is found to be
small when compared with that of
man. The facial angle, which in
the adult European is about 85°, is
in the ourang outang 67°, gradually
descending in some of the monkeys
as low as 30°, till among the other
genera of quadrupeds it does not
sometimes exceed 20°. It may be
mentioned, that the cerebral system
not only exhibits an ascending series
of advances, from the lowest fish up
to the highest mammal, but that,
in the highest mammal, a parallel
series of advances obtains, from the
fish-like condition of the brain, at
an early fa3tal age, up to its com-
plete development. Among the
vertebrate classes, the brain is the
most completely developed in the
mammalia, and, among the mam-
malia, in man. The characters
which serve to distinguish the brain
of mammalia from that of other
vertebrated animals consists, ac-
cording to Cuvier, in the existence
of a corpus callosum, a great comis-
sure, fornix, cornu ammonis, and
tuber annulare ; in the situation of
the tubercula quadrigemina; in the
absence of ventricles, or cavities, in
the thalami nervorum opticorum;
in the position of the above men-
tioned thalami within the hemis-
pheres, and in the alternate lines of
grey and white within the corpora
striata. The young of mammalia
are nourished for some time after
birth by milk, a fluid peculiar to
animals of this class, which is pro-
duced by the mammas at the time
of parturition, and remains as long

MAM

[275 1

MAM

as it is necessary. Mammalia con-
stitutes the first class of Spini-
Cerebrata or Yertebrata, and this
class has been divided by some into
ten orders.

1 . Bimana, or two-handed ; the
thumbs separate on the superior
extremities only. Example, man.

2. Quadrumana, or four-handed;
the thumb, or great toe, capable of
being opposed to the other fingers
or toes on each of the four extrem-
ities. The ape is an example.

3. Bradypoda, or slow moving
animals, with their bodies generally
covered by a hard crust. The
armadillo is an example.

4. Cheiroptera, wing-handed, or
animals having their fingers elon-
gated for the expansion of mem-
branes, which serve as wings.
This membrane commences at the
side of the neck, extends between
the feet and toes, serves to support
them in the air, and enables such
of them to fly as have their hands
sufficiently developed for that pur-
pose. The bat is an example.

5. Glires, or Eodentia. Gnaw-
ing animals, having large incisors
in each jaw, separated from the
molars by an empty space, by which
they divide hard substances. They
have no canine teeth ; they cannot
seize living prey nor tear flesh;
they cannot, even with their teeth,
cut their food, but they gnaw or
file it, hence their name. The
squirrel, mouse, hare, &c., are
familiar examples.

6. Ferae, or predaceous and
carnivorous animals. They have
large canine teeth, the molares
forming pointed prominences for
tearing and cutting the food. The
bear, hedge-hog, &c., are examples.

7. Solidungula, or Solipeda.
Animals having a single toe, or
hoof, on each foot. These have
six incisor teeth in each jaw, and
are all of them herbivorous. The
horse is an example.

8. Ruminantia, orPecora. The
term ruminantia indicates the
peculiar property possessed by
these animals of chewing the cud,
that is, of masticating their food a
second time, by bringing it back
to the mouth after having swallowed
it. This property depends upon
the structure of their stomachs, of
which they have four, the three
first being so disposed that the food
may enter into either of them, the
oesophagus, or gullet, terminating
at the point of communication.
They have two toes on each foot,
and no incisors in the upper jaw.
The sheep, goat, ox, &c., are fam-
iliar examples.

9. Pachydermata, or Belluae.
Thick-skinned animals. Animals
of unshapely form and a thick tough
hide. They have more than two
toes on each foot, some having
three, four, or five ; some of them
have large tusks, and a proboscis.
The elephant, rhinoceros, hippopo-
tamus, &c., are placed in this order.

10. Cetacea. These are mam-
miferous animals, destitute of hind
feet; their trunk terminates in a
thick horizontal tail with a cartil-
aginous fin. They live in the sea,
and their external form is that of
fishes, the fin of the tail excepted,
which in cetacea is horizontal,
while in fishes it is always vertical.
Their respiring by lungs, instead
of gills ; their possessing warm
blood ; their viviparous production ;
and their having mammas with
which they suckle their young, all
entitle them to be placed in the
class to which they belong. The
arrangement of mammalia by
Cuvier somewhat differs from the
above, and is as follows : — 1. Bi-
mana ; 2. Quadrumana ; 3. Carna-
ria; 4. Marsupialia; 5. Rodentia ;
6. Edentata; 7. Pachydermata; 8.
Ruminantia; 9. Cetacea.

Mammalia have been by a more
recent author divided into two

MAM

sub-classes, Placentalia and Impla-
centalia ; Placentalia comprising
13 orders, namely, Bimana, Quad-
rum ana, Carnivora, Artiodactyla,
Perissodactyla, Proboscidea, Toxo-
dontia, Sirenia, Cetacea, Cheirop-
tera, Insectivora, Bruta, Edentata,
and Rodentia; and Implacentalia
comprising 2 orders, mamely,
Marsapialia and Monotremata.

MAMMA'LIAN. Belonging to the class
Mammalia.

MAMMALI'FEROTJS. (from mammalia
and/6T0, to produce, Lat.) A- term
applied to strata containing mam-
miferous remains. As the mam-
maliferom crag of Norfolk, &c.

MA'MHAKY. Pertaining to the mam-
ma?, as the mammary glands, the
mammary arteries, &c.

MA'MMIFEB. (from mamma, a breast,
and fero, to bear.) All animals
having breasts and suckling their
young are included amongst the
mammifers. To these Linnaeus
assigned the name Mammalia.
Cuvier, however, called them
Mammifera\ but, as has been ob-
served, there appears no good rea-
son for altering the original term.

MA'MMILLAEY. Having small rounded
prominences, or projections some-
thing resembling teats or nipples ;
studded with rounded projections.

MA'MMILLATED. A term, like the one
immediately preceding it, applied
to certain minerals, which have
the appearance of small bubbles, or
rounded protuberances. Flint con-
taining calcedony, is generally
mammillated.

In conchology, the apex of a
shell when rounded like a teat, is
termed mammillated.

MA'MMOTH. (The etymology of this
word does not appear quite agreed
on ; some state it to be from a
Russian word, mamant ; some, that
it is of Tartar origin ; others, that
it is derived from Behemoth, an
Arabic word, signifying elephant.
Mammut, Germ.) The mammoth

276 ] MAM

appears to be quite extinct ; from
the fossil remains of it which have
been discovered, it appears to have
had the feet, tusks, trunk, and
many other particulars of confor-
mation in common with the ele-
phant ; but it differed from the
elephant in its grinders. Five
species have been distinguished.
The bones of the mammoth are
found in great abundance in Siberia,
and not only the bones, but por-
tions of the flesh and the skin, and
even whole animals have been
found in icebergs and in frozen
gravel. Towards the close of the
last century, the entire carcase of
a mammoth was exposed, and at
length fell to the ground from a
cliff of ice and gravel, on the banks
of the river Lena. This animal
was nine feet high, and about six-
teen feet in length ; the tusks were
nine feet long. The skin was
covered with hair, and it had a
mane upon the neck.

The mammoth appears to have
survived in England when the tem-
perature of our latitudes could not
have been very different from what
it now is ; for remains of this animal
have been found in a lacustrine for-
mation at North Cliff, in Yorkshire,
in which all the land and fresh-
water shells can be identified with
species now existing in that county.
We have no great certainty at what
period the mammoth ceased to exist;
it is commonly supposed that it be-
came extinct previous to the com-
mencement of the modern group,
but of this there is no good proof.
It is supposed, from the prodigious
number of bones found in certain
places, that the mammoth must
have existed in herds of hundreds,
or even thousands. According to
Pallas, there is scarcely a river,
from the Don, or the Tanais, to the
extremity of the promontory Tchus-
koinosa, in the banks of which the
bones of the mammoth are not most

MAM

[277]

MAN

abundant. There are two large
islands near the mouth of the river
Indigerska, which are said to be
entirely composed of bones of the
mammoth, intermixed with ice and
sand. Remains of the mammoth
have been found from Spain to the
coasts of Siberia, and throughout
all North America.

The grinders of the mammoth
are formed of two substances only ;
an internal bony substance, and a
thick covering of enamel. The
form of their crown is generally
rectangular, the crown being divided
by spreading grooves into a certain
number of transverse risings, each
of which is divided, in the contrary
direction, into two large obtuse,
and somewhat quadrangular and
pyramidical points ; the whole
crown, when not worn, being beset
with large points, arranged in pairs.
In consequence of several of these
teeth being much worn down, not
only to the base of the pyramids,
but even so low as only to leave one
square surface edged with enamel,
it has been concluded that they were
used in the trituration of vegetable
food. M. Cuvier particularizes
three sorts of these grinders; nearly
square, with three pairs of points,
generally much worn ; rectangular,
with eight points, less worn ; and
others with five pairs of points, and
a single smaller one, scarcely the
least worn. Cuvier considered
he had distinguished five different
species.

MANA'TTJS. A genus of herbivorous
cetacea, placed by Cuvier in the
family Cetacea herbivora. The
manatus appears to have inhabited
the seas of our latitude during the
Miocene and Pliocene periods. The
recent species are now found near
the coasts and mouths of rivers, in
the torrid zone. They have an
oblong body, terminated by an
elongated oval fin : the grinders
have a square crown, marked with

two transverse elevations; they
are eight in number throughout.
Lamantin, a name often given to
manatus, is said to be merely a
corruption of Manatus.

MA'NDIBLE. (mandibulum, Lat. ajaw.)
In insects, the upper jaws are called
mandibles; the under jaws, maxillae.
The mandibles of insects are two
strong, corneous, somewhat bent
hooks, the inner margin being more
or less dentate ; they articulate with
the cheeks at their broad basis, move
by ginglymus, and are opposed to
each other like the blades of scissors.

MAKDI'BULAB. Pertaining to the
jaw.

MANQANE'SE. (manganese, Fr. manga-
nese, It.) A metal but little known
in its pure or metallic state, to
which it is reduced with much
difficulty, in consequence of its
great affinity for oxygen. It was
first obtained in a metallic form by
Gahn, from the black oxide of
manganese, a substance first in-
vestigated by Scheele. When pure,
it has a grayish- white colour, with
some lustre. Its texture is granu-
lar; hardness, nearly that of iron.
Specific gravity from 7'0 to 8'0.
It has little or no malleability, and
is difficult of fusion. It absorbs
oxygen by exposure to the atmos-
phere, and its melting point is
about 160° "W.

In its metallic state, manganese
is not applied to any use. It is
obtainable in small quantities from
the black oxide by heating it in an
intense furnace, with charcoal and
a little oil.

The common ore of manganese
is the black, or peroxide, a valuable
substance to chemists, as that from
which oxygen is most easily ob-
tained ; it consists of 27'7 manga-
nese, and 16 oxygen. When added
in small quantities to glass, it
removes the greenish or yellowish
tinge which arises from iron or
other impurities ; but if added in

MAN

[278]

MAE

considerable quantity, it communi-
cates to glass or enamel a violet or
purple colour. The ores of man-
ganese present much diversity in
their external characters. All min-
erals containing any considerable
quantity of this metal, when melted
with borax and a little nitre, yield
a violet glass. One of the ores of
manganese, known by the name of
Slack Wadd, is remarkable for its
spontaneous inflammation when
mixed with oil.

MA'NON. A genus of zoophytes, found
in the cretaceous group and deter-
mined by Goldfuss.

MANGANE'SIAN GAENET. Grenat man-
ganesie of Brongniart ; Spessartine
of Beudant. A species of garnet
occurring massive and in dodeca-
hedral crystals variously modified.
Colour, a deep hyacinth or brown-
ish red : edges slightly translucent.
Fusible before the blow-pipe, and
when fused with borax and nitre
the borax is violet. According to
Klaproth it contains protoxide of
mangane 35-00, silica 35 '00 alu-
mine 14-25, protoxide of iron 14'00.
It occurs in granite.

MANTE'LLIA. A genus of fossil ani-
mals belonging to the chalk deposit.
This genus is thus described, " an
animal with a fusiform or ramose,
root-like pedicle, a stem and body
formed of tubuli, anastomosing in
a basket-like, texture, with open-
ings on the internal surface." The
name Mantellia has also been given
by Adolphe Brongniart, to a genus
of cycadeous fossil plants found in
the petrified forest of the Isle of
Portland.

MA'EBLE. (ma/rlre, Fr. marmo, It.
marmor, Germ, marmor, Lat.) Any
limestone possessing sufficient hard-
ness to take a polish may be called
marble. Many of these are fossil-
iferous; but statuary marble, which
is also called saccharine limestone,
from its possessing a texture re-
sembling that of loaf-sugar, ' is

devoid of fossils, and belongs to the
metamorphic series of rocks.

MA'EGAEATE. A compound of mar-
garic acid with potash, soda, or
some other base, and so named
from its pearly lustre.

MAEGA'EIC ACID. An oleaginous acid,
formed from different animal and
vegetable fatty substances.

MAEGAEITA'CEOTTS. ^Reflecting the pris-
matic colours like mother-of-pearl.
— Shuckard.

MA'BGAEITE. A mineral, of a grayish-
white colour, occurring massive
and in thin crystalline laminae,
intersecting each other in all direc-
tions. It bears some resemblance
to silvery mica.

MA'EGAEODITE. A mineral which is
described as forming the matrix of
black tourmaline.

MA'EGIN. (marge, Fr. mdrgine, It.)
The border or edge. In conchology,
the whole circumference or outline
of the shell in bivalves.

1. In conchology, having a promi-
nent margin or border.

2. In entomology, when the sharp
edge is margined, and surrounds
the surface with a narrow border.

MAEGINE'LLA. An ovato-oblong,
smooth univalve, with a short
spire. The lip thickly marginated
on the outside. The base of the
aperture slightly notched; the
columella plicated. Marginella
differs from Yoluta in the reflection
of its outer lip. Eecent Margi-
nella3 are found in sand and sandy
mud. Several fossil species have
been discovered in the calcaire
grossier.

MA'EINE'ALLTT'VIIJM. Shingle thrown
up by the sea ; materials cast upon
the land by a wave of the sea, or
those which a submarine current
has left in its track.

MAEI'NE VEGETA'TION. The marine
vegetation, says Sir C. Lyell, is
less known; but we learn from

MAR

[279]

MAE

Lomouroux, that it is divisible
into different systems, apparently
as distinct as those on the land,
notwithstanding that the unifor-
mity of temperature is so much
greater in the ocean. The number
of hydrophytes, or plants growing
in water, is very considerable, and
their stations are found to be in-
finitely more varied than could
have been anticipated ; for while
some plants are covered and uncov-
ered daily by the tide, others live
in abysses of the ocean, at the ex-
traordinary depth of one thousand
feet ; and although in such situa-
tions there must reign darkness
more profound than night, at least
to our organs, many of these vege-
tables are highly coloured.

MARL, (mergel, mar gel, Germ.) A
combination of common clay and
calcareous earth ; a mixture of clay
and lime.

MARL SLATE. A brown indurated
fossil shale, with occasional beds of
thin compact limestone : a rock of
the Permian period.

MARLSTONE. The name given to a
member of the lias which (the lias)
Sir E. Murchison states to be capa-
ble of a four-fold division. This
member of the lias, he says, is well
exposed in the hill on which the
church of Prees is built, both in
quarries and by the sides of the
rocks, dipping to the NYN.E. at low
angles. The upper beds are com-
posed of yellowish and greenish
thin-bedded sandstone, slightly mi-
caceous, and in parts calcareous;
the middle, of other yellowish
sandstones, some of which are more
calcareous ; and the lowest beds, of
sandy, dark-coloured slaty marl,
and shale with flattened spheroids
of impure lias limestone, which are
undistinguishable from the cement-
stone of the Yorkshire coast. The
marlstone is a well marked division
of the lias, being more arenaceous,
though still fine-grained, and often

bound by calcareous or ferruginous
cement into a hard stone. In
Gloucestershire it is divisible into
the "hard rock bed" above, and
the sands below. — Jukes.

MA'RLY. Composed of marl; con-
taining marl ; resembling marl.

MA'RTSTES IRISEES. The French geolo-
gists designate by this term the
upper party-coloured marls or clays
of the new red formation. They
are the same as the keuper-marls of
the Germans, and the gypseous and
saliferous marls of Cheshire, "Wor-
cestershire, &c., of England.

MA'RSIPOBRANCHII. The fifth order
of fishes, comprising the lampreys,
&c.

MARSTJ'PIAL. (from marsupium, a
pouch, Lat.) Having a pouch;
belonging to the order Marsupialia.
New Holland is known to contain a
most singular assemblage of mam-
miferous animals, consisting of more
than forty species of the marsupial
family.

MARSITPIA'LIA. (The term Marsupialia
is derived from the presence of a
large marsupium, or pouch, fixed on
the abdomen, in which the faatus
is placed after a very short period
of uterine gestation. Foetus ad
uterum maternum haud intermedio
placenta vera3 annexus.) Animals
possessing abdominal pouches. The
marsupialia form the fourth order
of Mammalia, in Cuvier's arrange-
ment. The economy of marsupialia
is in many respects most singular.
One most striking peculiarity is the
premature production of the foetus,
whose state of development at birth
is extremely small. Immediately
on their birth they pass into a sort
of second matrix. Incapable of
motion, and scarcely displaying
any germs of limbs or external
organs, these diminutive beings
attach themselves to the mamma?
of the mother, where they remain
fixed by the mouth, until they have
acquired a growth and development,

MAE

[ 280 J

MAR

resembling that of other newly-born
animals. The skin of the animal
is so arranged round the mammaB
as to form a pouch in which not
only the imperfect foetus, attached
to the nipple by its mouth, re-
mains till fully developed, but
into which, long after it is able
to run about, it leaps when
alarmed, or when wishing to
couceal itself. The order Marsu-
piala holds an intermediate place
between viviparous and oviparous
animals, forming a link, as it were,
between Mammalia and Reptiles.
The order Marsupialia contains
many genera, both herbivorous and
carnivorous. The kangaroo and
opossum are familiar examples.
Another peculiarity in these ani-
mals consists in this ; that the
members of two litters are some-
times sucking at the same time.
The New Holland opossums are
very voracious, and devour carcas-
ses as well as insects ; they enter
into the houses, where their vora-
city is very troublesome. That
most common, the Didelphys Vir-
giniana, attacks poultry in the night,
and sucks their eggs. It is said to
produce sixteen young ones in one
litter, which, when first born,
do not weigh more than one grain
each; though blind and almost
shapeless, when placed in the
pouch they instinctively find the
nipple, and adhere to it till they
attain the size of a mouse, which
does not take place till they are
are fifty days old, at which period
they begin to see. The discovery
of marsupials, both in the secondary
and tertiary formations, shows that,
so far from being of more recent
introduction than other orders of
Mammalia, this order is in reality
the first and most ancient condition,
under which animals of this class
appeared upon our planet, and as
far as our present discoveries go, it
was their only form during the
secondary period.

MAESUPIOCETNI'TES. (from

Gr. marsupium, Lat. a purse, and
Kplvov, Gr. a lily.) The name
given by Mr. Phillips to a genus of
encrinites belonging to the Silurian
rocks.

MA'ESUPITE. (from marsupmm, a
purse, Lat.) The name given by
Dr. Mantell, from their resemb-
lance to a purse, to a genus of
Crinoidea found in the chalk. The
marsupite was a molluscous animal,
of a sub-ovate form, having the
mouth in the centre, and surrounded
by arms, or tentacula. The skel-
eton was composed of crustaceous,
hexagonal plates : the arms, sub-
divided into numerous branches of
ossicula, or little bones : the whole
invested with a muscular tissue, or
membrane. When floating, the
creature could spread out its tenta-
cula like a net, and by closing
them, seize its prey, and convey it
to its mouth. Fossil remains of
this zoophyte have been found in
the upper chalk of Sussex, Wilt-
shire, and Yorkshire. The name
of 'cluster-stones,' given to them
by the quarry- men of Sussex, con-
veys an idea of their general ap-
pearance. They may, however, so
far as their body is concerned, be
compared to the fruit of the pine.
The body is orbicular, contained in
a pelvis composed of sixteen con-
vex, radiated, angular, crustaceous
plates. The marsupite was once
placed among the encriuites, from
which it differs most essentially,
inasmuch as it possesses neither a
vertebral column nor any processes
of attachment : from which cir-
cumstances it is clearly manifest
that it was not attached to one
place or point, but floated about in
the surrounding sea. The marsu-
pite may be considered as forming
a link between the Crino'idea and
the Stellarida3.

MABSU'PITTM. The name given to a
dark-coloured membrane situated
in the vitreous humour of the eye

MAS

[281 ]

M E A

of birds. The use of the marsupium
is not ascertained, but it is present
in almost every bird having ex-
tensive powers of vision.

MA'SCAGNINE. A native sulphate of
ammonia, found, by M. Mascagni,
near the warm spring of Sasso, in
Tuscany, and named after its dis-
coverer. It has also been called
Sassolin, from the place near which
it was found.

MA'SSETER. (from fjiaaaao^ai, Gr. to
chew.) A muscle connected with
the under jaw of insects, and which
assists in masticating.

MA'SSIVE. A term used in mineral-
ogy to describe a substance of no
determinate form, whatever its
internal structure may be : it is,
however, generally applied to
minerals possessing regular internal
structure, but having no character-
istic external form.

MA'STODON. (from ^CUTTO?, a breast or
udder, and oSovs, a tooth, Gr.) A
name given by Cuvier to a genus
of fossil mammalia. The remains
of the mastodon were first dis-
covered at Albany, near Hudson
river, about the year 1711. The
first specimens brought to Europe
were obtained from the neighbour-
hood of the Ohio, from which
circumstance the French called the
mastodon the animal of the Ohio.
Several species have been dis-
tinguished. "The Great Masto-
don," says Griffith, "is one of the
most remarkable and apparently
the most enormous of all the fossil
species. Bones of this species are
found in abundance over all North
America, from the 43rd degree of
north latitude, as far south as
Charlestown, in Carolina, in thirty-
three degrees, and, as far as we
at present know, do not exist in
any other country of the globe.
They are found at moderate depths,
exhibiting few marks of decompo-
sition, and none of detrition."
The great mastodon was very

similar to the elephant in the tusks
and entire osteology, the cheek-
teeth excepted. It is supposed
to have possessed a trunk ; its
height, about which very false and
exaggerated notions once prevailed,
does not appear to have exceeded
ten or twelve feet, but its body
was longer than that of the recent
elephant, its limbs were thicker,
and its belly less bulky. The
structure of its molars, is sufficient
to constitute it a different genus.
" Two dental characters exist
which distinguish, in a well-marked
and unequivocal manner, the genus
Mastodon from the genus Elephas.
The first is the presence of two
tusks in the lower jaw of both
sexes of the mastodon, one or both
of which are retained in the male,
while both are early shed in the
female. The second character is
equally decisive ; it is the displace-
ment of the first and second molars,
in the vertical direction, by a tooth
of simpler form than the second, a
true dent de r emplacement, developed
above the deciduous teeth in the
upper, and below them in the
lower jaw." — Prof Owen.

MA'STOID. (from /uurros, the breast,
and ef<5o9, likeness, Gr.) Shaped
like the breast, or like a nipple.
Applied to some prominences of
bones ; to a foramen ; to a muscle ;
and to cells in the ear.

MA'TRIX. (matrix, Lat. matrices, pi.)
In mineralogy, the earthy or stony
matter in which a fossil is im-
bedded. Called also gangue.

MAXI'LLA. (maxilla, Lat.) The jaw.
The lower jaws of insects are cal-
led maxillae ; they are placed be-
hind the mandibles, and between is
situated the labium, or lower lip.
The maxillaa are employed princi-
pally for holding the substances on
which the grinding apparatus of
the mandible is exerted.

MEAN QUANTITIES. Such as are inter-
mediate between others that ar

o o

M E A

L 282

MED

greater and less. The mean of any
number of unequal quantities is
equal to their sum divided by their
number. For instance, the mean
between two unequal quantities is
equal to half their sum. — Mrs.
Somerville.

MEAG'BE. A term used in mineralogy
relating to the touch or feel of a
mineral. Chalk is said to be
meagre.

MEANDBI'NA. Brain-stone ; brain-
coral. Madrepores in which the
laminae assume a meandering di-
rection are called meandrinae. Me-
andrinae are large hemispherical
corals, having their surface covered
with serpentine ridges and de-
pressions, resembling the convo-
lutions of the cerebrum, or brain,
from which circumstance they have
been called brain- stone. " On the
convex side," says Mr. Parkinson,
"are excavated, open, winding,
ambulacrae, lamellated on each
side. The lamellae are transverse
and parallel, adhering on each side
of hillock-shaped ridges. The la-
mellated ridges occupy the inter-
stices of the tortuous vallies which
hold the polypes and thus separate
them. Fossil meandrinae are found
both in the cretaceous and oolite
series."

(Lat.) A passage, as that
leading to the ear, called the
meatus auditorius, &c.
MEDIAL ORDEE. A term proposed by
the Rev. J. Conybeare for that
assemblage of rocks which contains
not only the great coal deposit
itself, but also the limestone and
sandstone on which it reposes.
" This series of rocks," says Dean
Conybeare, " is by some geologists
referred to the flcetz, and by others
to the transition class of the
Wernerians. We have preferred
instituting a particular order for
its reception, a proceeding justified
by its proportional importance in
the geological scale, its peculiar

characters, and the many incon-
veniences arising from following
either of the above conflicting
examples. For this order we have
proposed the name of Medial,
wishing to adopt an appellation
entirely free from theory ; and
indicating only the central position
of this groupe in the five-fold
division of the geological series
which results from assigning to it
a separate class."

MEDTJ'LLA. (medulla, the marrow,
Lat.)

1. In botany, the pith of plants.

2. The marrow in the cavities of
bones.

ME'DTTLLARY. (medullaris, Lat.)

1. Eclating to the brain, or to the
marrow. The medullary substance
composes the greater part of the
brain, spinal marrow, and nerves.

2. In botany, relating to the pith
of plants.

MEDTJ'LLIN. A name given by Dr.
John to the porous pith of the sun-
flower.

MEDT/SA. A genus of marine mol-
luscous animals belonging to the
class Acalepha. The medusce ap-
proach nearly to the fluid state,
appearing like a soft and transpa-
rent jelly, which by spontaneous
decomposition after death, or by
the application of heat, is resolved
almost into a limpid watery fluid.
The usual form of a medusa is that
of a hemisphere, with a marginal
membrane, like the fold of a man-
tle, extending loosely downwards
from the circumference.

Medusce are met with of very
various sizes; the larger abound
in the seas around our coasts, but
immense numbers of the more
minute, and often microscopic,
species occur in every part of the
ocean. In some parts of the Green-
land seas the number of Medusae is
so great, that in a cubic inch, taken
up at random, there are not fewer
than 64. In a cubic foot this will

MEG [ 283 1

amount to 110,592 ; and in a cubic
mile, the number is such, that
allowing one person to count a
million in a week, it would have
required 80,000 persons from the
creation of the world, to complete
the enumeration.

MEGA'CEBOS. A sub-genus of the
genus cervus, and so named from
the immense size of its antlers; the
Megaceros Hibernicus, or Irish
fossil elk, is a species of this sub-
genus. The first tolerably perfect
specimen of the Irish elk was found
in the Isle of Man. A very com-
plete and well articulated skeleton
is in the British Museum, another
in the "Woodwardian Museum, at
Cambridge, and a third in the
Hunterian Museum, at the College
of Surgeons.

MEGALO'NYX. (from /ueyas, great, and
owgt a claw, Gr.) A huge fossil
mammalian, of the order Edentata,
and thus named from the great size
of its unguical, or claw, bones.
The remains of the Megalonyx
were discovered in the floor of a
cavernr in the limestone of Vir-
ginia, in America. Cuvier approx-
imated the Megalonyx to the
Megatherium, considering that
these two animals must have con-
stituted an intermediate genus
between the bradypi and the ant-
eaters. He concludes that they
were both herbivorous. The Meg-
alonyx has hitherto been found
fossil only.

MEGALI'CHTHYS. (from //^a?, great,
and /x^s/ a fish, Gr.) The name
given to a fossil sauroid fish, first
discovered, by Dr. Hibbert, in the
limestone near the bottom of the
coal formation, near Edinburgh.

MEGALO'DON. A genus of fossil bivalve
shells, found hitherto only in the
Devonian system of rocks ; they
are equi valve, longitudinal, thick,
the hinge forming an incrassated
septum across the cavity of the
shell, with a large compressed bifid

MEG

tooth in the right valve, and one
irregular and pointed tooth in the
left. Two species are described. —
Lycett.

MEGALO'SAUB. } (from pe^a<?, great,

MEGALOSAU'BUS. ) and aavpos, a liz-
ard, Gr.) A genus of fossil am-
phibious animals, of great size,
belonging to the saurian tribe ;
holding an intermediate place
between the crocodiles and mon-
itors. Cuvier concludes, from a
comparison of the fossil bones with
those of existing lizards, the mega-
losaurus to have been an enormous
reptile measuring from forty to
fifty, or even seventy, feet in length,
and partaking of the structure of
the crocodile and monitor, but more
nearly approximating the latter.
Remains of the megalosaurus have
been found in the Oolite and in the
"Wealden. This huge creature
appears to have been carnivorous,
from the form of its teeth, and its
head terminated in a straight and
narrow snout.

MEGAPHY'TON. (from ^'(yasr, great,
and 0vToi/, a plant.) An extinct
genus of plants belonging to the
order Conifera. In the genus
Megaphyton the stem is not fur-
rowed, and the leaf scars are very
large, resembling the shape of
horse- shoes, and arranged on each
side of the stem in two vertical
rows. It is found in the coal
strata.

MEGATHERIUM, (from /^e'r/as, great,
and Oypiov, a beast.) An extinct
animal, of great size, of the family
tardigrada, belonging to the order
Edentata, nearly allied to the sloth,
and, like the sloth, presenting an
apparent monstrosity of external
form, accompanied by many singu-
lar peculiarities of internal struc-
ture. Fossil remains of the mega-
therium have been discovered in
South America, in the alluvial
deposites of the Pampas. The
megatherium was about eight feet

M E I

[ 284 ]

MEL

high, its haunches five feet wide,
its feet a yard in length, and its
body twelve feet long : it united
part of the structure of the arma-
dillo with that of the sloth. The
relative proportions of the extremi-
ties of the megatherium differ
greatly from those of the sloth,
and indeed from those of any known
animal. Its teeth prove that it
lived on vegetables, and its fore-
feet, robust, and armed with sharp
claws, show that roots were its
chief objects of search. Its hide
appears to have been covered with
a bony coat of armour of consider-
able thickness, the use of which
was probably defensive, not only
against the sharp claws of beast of
prey, but also against the myriads
of insects that surrounded it. Its
tail was long, and composed of
vertebra of enormous magnitude,
the body of the largest being seven
inches in diameter, and the hori-
zontal distance between the ex-
tremities of the two transverse
processes, being twenty inches. If
to this be added the thickness of
the muscles and tendons, and of
the shelly integument, the diameter
of the tail, at its largest end must
have been at least two feet; and
its circumference, supposing it to
be nearly circular, about six feet,
secure within the panoply of his
defensive armour, where was the
enemy that would dare encounter
this behemoth of the Pampas? a
creature whose giant carcase was
encased in an impenetrable cuirass,
and who, by a single pat of his
paw, or lash of his tail, could in an
instant have annihilated the couguar
or the crocodile. The genus me-
gatherium comprehends two species,
the megatherium, properly so called,
and the megalonyx.
MEI'ONITE. (from peiwv, less, Gr.)
The Meionit of Werner. A mine-
ral, thus named from its termina-
ting pyramids being lower than those

of similar forms in other minerals.
Meionite is a prism ato-pyramidal
felspar. It occurs in grains, or
small crystals, whose more common
form is an eight-sided prism, trun-
cated on its lateral edges, and ter-
minated by four low-sided pyramids.
It is of a greyish- white colour;
translucent, and sometimes trans-
parent. It scratches glass, and
before the blow-pipe readily melts
into a white spongy glass. It
is found at Mount Somma, near
Vesuvius.

MELA'NIA. (from /ieXas, black, Gr.)
A genus of univalve fresh-water
shells belonging to the order Pec-
tinibranchiata, class Mollusca. The
melania is a turreted univalve ; the
aperture entire, ovate, or oblong,
and spread out at the base of the
columella, which is smooth. Recent
melania3 are found in rivers and
estuaries. Fossil melaniae are found
in the environs of Paris.

ME'LANITE. (from yiieXas, black, Gr.)
The Melanit of Werner; Grenat
noir of Haiiy ; Grenat melanit of
Brongniart. A velvet black,
opaque, dodecahedral variety of
garnet. It occurs in crystals,
which are dodecaedrons, with trun-
cated edges. Fracture conchoidal.
Specific gravity 3 '73. Its con-
stituents are silex 3Sf5, lime 32*5,
oxide of iron 25'25, alumine 6,
oxide of manganese '04. It is
found at Frascati, near Mount
Vesuvius, in Bohemia, and in
JSTorth America.

MELANO'PSIS. A genus of oval or
oblong, fusiform, univalves, be-
longing to the family Melaniana,
in Lamarck's arrangement. M^ela-
nopsides are found both recent and
fossil ; they are distinguished from
Melanias by a notch in the aperture.
Fossil melanopsides are found in
the shale of the Wealden, at
Pounceford.

ME'LAPHYB. j A compact, fine-

ME'LAPHYBE. j grained, dark

MEL

[285]

MEM

grey, brown, or black rock, con-
sisting apparently, of a feldspathic
mineral intimately mixed with
augite, hornblende, magnetic iron,
&c. It is sometimes vesicular,
amygdaloidal, or porphyritic, and
and is said to be sometimes slaty.
— Juices.

MELA'STOMA. (from ^e\as, black,
and ffTopa, mouth, Gr.) A name
given to a genus of plants, belong-
ing to the order Melastomacea,
from the fruit staining the lips of
a black colour.

MELEAGRI'NA. A genus of bivalve
molluscans, known as the pearl-
oyster. MeleagrinaB inhabit the
Persian Gulf, the coasts of Ceylon,
the sea of New Holland, the Gulf
of Mexico, and the coasts of Japan.
It attains perfection nowhere but
in the equatorial seas ; in the pearl
fishery of the island of Ceylon it is
the most celebrated and productive.
The pearls are situated in the
fleshy part of the oyster, near the
hinge. For one pearl that is found
perfectly round and detached be-
tween the membranes of the
mantle, hundreds of irregular ones
occur attached to the interior of the
shells, like so many warts: they
are sometimes so numerous, that
the animal cannot shut its shell,
and so perishes.

ME'LILITE. (from [neXi, honey, and
X/009, a stone, Gr.) The name
given to a rare mineral, from its
honey colour. It occurs only in
very minute crystals, perfectly
regular and well defined, but not
larger than a grain of millet- seed.
These grains are of a cubic or
prismatic form ; their surface is
often coated with an oxide of iron.
They are glistening, semitrans-
parent, and will scratch glass.

MELI'TA. (from met, honey, Lat.)
Honey-cake. A genus of echinites,
belonging to Catocysti.

ME'LLATE. The name given to a
salt, in which mellitic acid is

combined with any salifiable base.

ME'LLITE. (from met, honey, and
X/0os, a stone.) Honey- stone. The
Honigstein of "Werner ; La Pierre
de miel of Brochant ; Pyramidales
Melichron-Hartz of Mohs. This
mineral was first observed in Thu-
ringia, where it occurs associated
with brown-coal. It is of a honey-
yellow colour, whence its name,
and is usually crystallized in small
octahedrons, whose angles are often
truncated. Fracture conchoidal.
Lustre shining or splendent. By
friction the crystals acquire a weak
negative electricity. They are
more or less translucent, or even
transparent, and exhibit double
refraction. Mellite may be distin-
guished from amber by its weak
electricity, and double refraction.
It consists of mellitic acid 41 -0,
alumina 14*10, water 44'8.

MELOCRINI'TES. A genus of encrinites
established by Goldfuss. It is
found in the mountain limestone.

MEMBBANA'CEOTJS. (memlranaceus,
Lat.) Resembling membrane. In
botany, a membranaceous leaf has
no distinguishable pulp between
the two surfaces.

MEMBEA'NEOUS. (membraneus, Lat.)
Consisting of membrane. In this
and the preceding word may be
observed the difference between
words ending in aceous and eous :
those ending in aceous express a
resemblance to a material, those
ending in eous indicate the material
itself.

ME'MBEANE. (membrana, Lat.) The
membranes of animals are thin
semitransparent bodies, which en-
velope certain parts of the body, to
which they furnish a covering for
their support and protection. Mem-
branes are modifications of cellular
texture, the surfaces of the plates
cohering so as to obliterate all the
cellular interstices, and being im-
pervious to fluids. Membranes
also line the interior of all the

MEN

[ 286 ]

M E R

large cavities of the body : these
membranes, after lining the sides
of their respective cavities, are
reflected back upon the organs
which are enclosed in those cavities,
so as to furnish them with an ex-
ternal covering. Thus the bowels
are covered by the peritoneum, the
lungs by the pleur® ; nevertheless,
. in consequence of these membranes
being reflected, the lungs and
bowels may be said to be external
to their investing membranes.

ME'NACHINE. (from Menachan, a val-
ley in Cornwall.) The name given
to a metal, to which the name
titanium is now more generally
applied. The menachine of Gregor
and the titanium of Klaproth are
the same substance, and to Gregor
is owing the merit of the discovery.

ME'NACHANITE. (from Menachan, or
Menaccan, in Cornwall.) An oxide
of titanium, or menachine, com-
bined with iron. It is of a greyish-
black colour, and occurs in small
grains resembling gunpowder, of
no determinate shape, and mixed
with a fine grey sand. Specific
gravity 4'4. Before the blow-pipe
it neither decrepitates nor melts.
According to the analysis of Klap-
roth, it consists of oxide of iron
51-00, oxide of titanium 42'45,
silica 3 '50, oxide of manganese
0-25.

ME'NILITE. (from Menil-montant,
near Paris, where it is found.) The
Menilit of Werner ; Silex meni-
lite of Brongniart ; Quartz resinite
subluisant of Hau'y. A brown or
yellowish-grey tuberose variety of
uncleavable quartz. By some
authors this mineral is placed as a
variety of semi-opal. From its
only having been found at Menil-
montant, near Paris, and from the
resemblance of some of its darker
varieties to pitch, it is sometimes
called Pitch-Stone of Menil-mon-
tant. Hoffmann divided Menilite
into two subspecies, namely, Brown

Menilite and Grey Menilite. Meni-
lite occurs in small irregular or
roundish masses, often tuberose, or
marked with little ridges on its
surface. It is translucent, often
only at its edges. Structure rather
slaty ; fracture conchoidal or splin-
tery. It scratches glass. Specific
gravity 2-18. Infusible before the
blow-pipe. Constituents, silica
85-5, alumine 1, lime 0-5, oxide of
iron 0'5, water and carbonaceous
matter 11.

MENI'NGES. (from ^v^g, Gr., a
membrane.) A name given to the
membranes which cover the brain.

MENI'SCUS. (from ytn/wWos, Gr. A
lens, one of whose surfaces is
convex and the other concave, and
in which the two surfaces meet if
continued. As the convexity
exceeds the concavity, a meniscus
may be regarded as a convex lens.

MEPHI'TIC A'CID. Another name for
carbonic acid.

MEPHI'TIC AIE. Another name for
nitrogen gas.

MEECTJEY. (mercure, Fr. mercuric, It.)
One of the sixty simple or elemen-
tary bodies. This metal is of the
same colour as burnished silver;
when pure and fluid, it is still
opaque, and nearly silver-white,
with a strong lustre. Its specific
gravity is 13-56, or thirteen times
and a-half heavier than water, its
density being next to those of plat-
inum and gold. Mercury freezes at
a temperature of 39° or 40° below
the zero of Fahrenheit, that is, at
a temperature of 71° below the
freezing point of water ; under
common circumstances we always
find it fluid, and in this respect it
remarkably differs from all the
other metals. It has obtained its
name from its fluidity and colour.
The boiling point of mercury is
somewhere about 680°, at which
temperature it is converted into
vapour of a highly expansive
power j this vapour may be again

M E H

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M E 8

condensed into the fluid metal, by
being received into cold vessels.

Mercury has less affinity for
oxygen than most other metals ; it
may be distilled over five hundred
times, without loss of quantity.
It combines, however, with oxygen
in two proportions, forming a red
and a black oxide. By merely
heating these in a retort the oxygen
may be driven off, and the metal
once more obtained in its pure state.

The existence of mercury, even
in small quantities, in any of its
ores, may be ascertained by ming-
ling the ore with iron filings, and
heating this mixture to redness
under any cold body, as a plate of
polished copper ; the mercury is
volatilized, and condensed in mi-
nute globules on the plate. In
consequence of the volatility of
mercury, it is usually purified by
distillation.

Two of the combinations of mer-
cury with chlorine form most
valuable and important medicines ;
the one called chloride of mercury,
or calomel, the other bichloride of
mercury, or corrosive sublimate.
From the fluid state in which
mercury exists, it readily combines
with most of the metals, to which,
if in sufficient quantity, it imparts
a degree of fusibility or softness :
these compounds are termed amal-
gams. An amalgam of mercury
and tin is employed for silvering
the backs of looking glasses, and
an amalgam of four parts of mer-
cury, two of bismuth, one of lead,
and one of tin, is used for silvering
the inside of glass globes, the
amalgam fusing on the globe being
placed in hot water. The ready
combination of mercury with gold
or silver, and the facility with
which it may be again separated
from them by heat, renders it of
great value in the obtaining those
metals from their ores and alloys
in the operations of mining.

Mercury is also most useful in
the construction of barometers and
thermometers. It was known in
the remotest ages, and seems to
have been employed by the an-
cients in gilding, and in separating
gold from other bodies, as in the
present day. It possesses neither
taste nor smell. Native mercury
occurs in small globules, dissemina-
ted in other metals. These glo-
bules are but feebly united to their
gangue, and may be liberated by
striking or heating the substance
which embraces them. It is from
the sulphuret of mercury that the
metal is principally obtained.
Sulphuret of mercury occurs in
beds, or large irregular masses, and
sometimes in veins. The mines
which furnish the ore, sulphuret of
mercury, are by no means common;
Spain, Germany, and Peru possess
the most important. In Spain, at
Almaden, these mines are in a
mountain of argillaceous slate or
shale. The most celebrated, how-
ever, are at Idria; these are situ-
ated partly in gray compact lime-
stone, and partly in shale. The
working these mines is exceedingly
injurious to the health and life of
those employed. Criminals, and
those convicted of political offences,
are sent hither to eke out a miser-
able existence. They soon lose
their teeth, and are subject to
paralysis, convulsions, and prema-
ture old age. It is said that the
surrounding district is so affected
by the noxious vapours, that cattle
cannot be reared there, and that
fruit and grain do not come to
maturity.

MERE. A deep pool of fresh water.

ME'BOE. In malacology, the name
given by Schumacher to certain
co wry- shells.

MERSTHAM BEDS. See Firestone.

ME'SENTERY. (pecrevrepiov, Gr. from
fieffos, middle, and zvvepov, bowel.)
A fatty membrane formed of folds

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MET

of the peritoneum. This is a fine
and delicate membrane which con-
nects the intestines to the spine,
and to each other, and which ap-
pears to be interposed in order to
allow to the intestines that freedom
of motion which is so necessary to
the proper performance of their
functions.

MESENTE'BIC. Pertaining to the me-
sentery, as the mesenteric glands,
&c.

MESOTHO'BAX. (from ^teo-o?, middle,
and Owpag, chest.) In entomology,
the mesothorax gives origin to the
second pair of legs, and also the
first pair of wings, or to the elytra,
of insects.

ME'SOTYPE. (from ^e'<roe, middle, and
TV?™?, form.) Prismatic zeolite ;
a simple mineral of the zeolite
family, occurring in drusy cavities,
or in veins in secondary trap rocks.
Mesotype is of a white, red, yellow,
or yellowish-brown colour. It
occurs regularly crystallized. It
consists of silica 54' 40, alumina
19-75, soda 15-05, lime 1'60, water
9-80. Specific gravity 2-3.

MESOZ'OIC. A palseontological term,
corresponding to, or synonymous
with, secondary. The Mesozoic, or
secondary, epoch comprises the cre-
taceous, the oolitic, and the triassic
periods.

METACA'BPAL. Belonging to the wrist ;
as the metaca/rpal bones, &c.

METACARPUS, (from /tera, with, and
Kapiro-s, the wrist.) That part of
the superior extremity which con-
nects the wrist with the fingers ;
commonly known as the hand, but
not including either the wrist or
the fingers.

METABO'LIANS. (from fjucT-apaXXw, Gr.
to change.) That sub-class of in-
sects which undergo a metamor-
phosis, and are usually fitted with
wings in their final state.

ME'TAL. (/uera\\ov, Gr. metattum,
Lat. metal, Fr. metdllo, It. metall,
Ger m . ) "A metal may be described

as a shining opaque body, a good
conductor of heat and electricity,
insoluble in water ; capable, when
in a state of oxide, of uniting with
acids, and of forming with them
metallic salts." — Phillips. Metals,
as presented by nature, are some-
times pure, or combined with each
other only, and are said to exist in
a metallic state. But more fre-
quently they are combined with
oxygen, sulphur, &c., by which
their peculiar metallic properties
are more or less disguised ; in this
case the metal is said to be mine-
ralized, and the oxygen, or sulphur,
is called the mineralizer. All the
individuals of the class of metals,
with the exception perhaps of iron,
are perfectly inert and harmless;
even arsenic, lead, copper, and
mercury, which in certain states
of combination constitute some of
the most virulent of known sub-
stances, exert no action upon the
living system, unless they be in
union with some other body ; but
when so united, how valuable do
they become, and what various
medicinal effects may they not be
made to produce ! The metals at
present known are forty-four in
number. Of these, seven were
known in the earliest ages, and, in
consequence of a superstitious belief
in the influence of the stars over
human affairs, were first distin-
guished by the names and signs of
the planets ; and as the latter were
supposed to hold dominion over time,
so were astrologers led to believe
that some, more than others, had
an influence on certain days of the
week; and, moreover, that they
could impart to the corresponding
metals considerable efficacy upon
the particular days which were
devoted to them. As regards the
ages of metals, tin, molybdena,
tungsten, and wolfram, are ranked
as the most ancient ; uranium and
bismuth succeed. Gold and copper

MET

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are deemed relatively and compara-
tively as new metals. Iron is of
all ages. The specific gravity of
metals, if we exclude those recently
discovered by Sir H.Davy, is always
greater than that of minerals ; tellu-
rium, the lightest metal, being above
6'0, while the heaviest earthy body
is less than 5'0. Metals are opaque;
they possess a peculiar lustre, which
has been termed metallic lustre,
retaining it even when reduced to
powder. They are mostly malle-
able, or capable of being hammered
into various orders and thin leaves ;
and ductile, or capable of being
drawn into wires of greater or less
fineness. They are not soluble in
water. They all unite with oxygen,
and, probably, all with chlorine.
They are fusible, or capable of being
rendered fluid by a heat attainable
by artificial means ; becoming again
solid on cooling. They are elastic,
hard, heavy, and, generally, sono-
rous. Some of the metals possess a
degree of taste and smell. All the
metals are expansible by heat, and
their degree of expansibility appears
to bear a relation to their fusibility.
Two or three of the metals occur
in small quantities in the masses of
some of the earlier rocks, but in
general the metals are found in
veins ; some in veins traversing the
older rocks, and rarely or never in
those of a more recent description ;
others most abundantly, or only in
those of newer formation.

METALLIC LTJ'STRE. One of the most
conspicuous properties of metals is
a particular brilliancy which they
possess, and which has been called
the metallic lustre. There are other
bodies which apparently possess this
peculiar lustre, as, for example,
mica, but in them it is confined to
the surface, and accordingly dis-
appears when they are scratched,
whereas it pervades every part of
metals.

META'LLIC QBE. Metals existing in

the state of an oxide, or a salt,
or united with a combustible, are
called ores ; and this term is, by
analogy, extended to the native
metals and alloys. They appear to
be the production of every period,
but more frequently exist in pri-
mary and transition, than in secon-
dary rocks, or than in alluvial
earths.

META'LLIC O'XIDE. A metal combined
with any proportion of oxygen, is
called a metallic oxide, provided it
does not possess the properties of an
acid.

META'LLIC SALTS. Those salts which
have a metallic oxide for their base;
carbonate of lead is an example.

METALLIC VEINS. "Perhaps," says
Mr. Bake well, " the reader may
obtain a clearer notion of a metallic
vein, by first imagining a crack or
fissure in the earth, a foot or more
in width, and extending east and
west on the surface, many hundred
yards. Suppose the crack, or fis-
sure, to descend to an unknown
depth, not in a perpendicular direc-
tion, but sloping a little to the
north or south. Now, let us sup-
pose each side of the fissure to
become coated with mineral matter,
of a different kind from the rocks
in which the fissure is made, and
then the whole fissure to be filled
by successive layers of various
metallic and mineral substances ;
we shall thus have a type of a
metallic vein. Its course from
east to west is called its direction,
and the dip from the perpendicular
line of descent, is called its hading"
" There is a remarkable circum-
stance," says Prof. Phillips, " in
the distribution of metallic veins
in the same class of stratified rocks,
— a peculiarity depending on local
influences; such, that while the
slates of Cornwall near the granitic
eruptions, yield tin and copper, and
the Snowdonian slates, and those
of Coniston Water Head yield

MET

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•copper ; those of Loweswater, Bor-
rowdale, Patterdale, and Caldbeck
fells yield lead, or lead and
copper."

METALLI'FEEOUS. (from metallum,
metal, and/m>, to produce.) Yield-
ing metal; as metalliferous deposits,
metalliferous districts, metalliferous
veins, metalliferous dykes, &c.

META'LLUEGY. (from fj^Ta\\ov, a
metal, and ep<yov, a work, Gr.
mbtallurgie, Pr.) Some authors
comprehend under this term, the
whole art of working metals, from
the glebe, or ore, to the utensil ;
in which sense assaying, smelting,
refining, parting, smithery, gilding,
&c., are only branches of metal-
lurgy. Others restrain metallurgy
to those operations required to sep-
arate metals from their ores.

METAMO'BPHIC. (from fie™, trans,
and popcjtri, forma, Gr.) A term
proposed for such hypogene rocks
as are stratified, or altered by strat-
ification ; any stratified primary
rock may be termed metamorphic.
By some authors the metamorphic
rocks have been divided into two
groups ; namely, those which pre-
sent traces of stratification, and,
secondly, those which present no
appearance of regular arrangement,
but occur in amorphous or shape-
less masses. The term metamor-
phic has been assigned by Sir C.
Lyell to a certain division of rocks
comprising the crystalline strata or
schists, called gneiss, mica schists,
clay slate, chlorite schist, marble,
and the like, the origin of which is
more doubtful than that of the
other divisions. The metamorphic
rocks are either those in which the
original structure and composition
are still obvious, or those in which
those characters are altogether
obscured and replaced by others,
produced either by heat, or pressure,
or both conjoined. The metamor-
phic rocks may be divided into two
sub-groups, those in which the

original mineral structure is still
recognizable, the particles, however
altered, not having entered into
new combinations, and those where
such new combinations have been
effected. — Jukes.

METAMO'RPHOSIS. (fierafiop^wffi^, Gr.
change into another form, metamor-
phose, Fr. metamdrfosi, It.) Trans-
formations which insects undergo
previously to their arriving at their
state of perfection. The progress
of metamorphosis of insects is most
strikingly displayed in the history
of the Lepidopterous, or butterfly
and moth tribe. The egg, which
is deposited by the butterfly, gives
birth to a caterpillar; an animal
which, in outward shape, bears not
the slightest resemblance to its
parent, or to the form it is itself
afterwards to assume. It has, in
fact, both the external appearance,
and the mechanical structure, of a
worm. But these vermiform in-
sects contain in their interior the
rudiments of all the organs of the
perfect insect. These organs are,
however, concealed from view by a
great number of membraneous cov-
erings, which successively invest
one another, like the coats of an
onion, and are thrown off, one after
another, as the internal parts are
gradually developed. These suc-
cessive peelings of the skin are but
so many steps in preparation for a
more important change. A time
comes when the whole of the cover-
ings of the body are at once cast
off, and the insect assumes the
form of a pupa or chrysalis ; being
wrapt as in a shroud, presenting no
appearance of external members,
and retaining but feeble indications
of life. In this condition it re-
mains for a certain period, its
internal system continuing in secret
the farther consolidation of the
organs, until the period arrives
when it is qualified to emerge into
the world, by bursting asunder the

MET

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MIC

fetters which had confined it, and
to commence a new career of
existence. The worm, which so
lately crawled with a slow and
tedious pace along the surface of
the ground, now ranks among the
sportive inhabitants of the air ; and
expanding its newly acquired
wings, launches forward into the
element on which its powers can
be freely exerted, and which is to
waft it to the object of its gratifica-
tion, and to new scenes of pleasure
and delight. — Dr. Eoget.

METATA'RSAL. Belonging to the foot,
as the metatarsal bones, &c.

METATA'RSUS. (from /tera and rapao?,

. Gr. mttatarse, Fr.) That part of
the foot which lies between the
ankle and the toes, corresponding
to the metacarpus of the superior
extremities. The bones of the
metatarsus in the most complete
forms of development are always
five in number, in each limb.

METATHO'BAX. (from ^era, beyond,
and 0u>paj~, the chest.) In ento-
mology, the third and last segment
of the thorax, resembling the
second in being of a more united
structure than the first. The
second and third segments are
closely united together, but the
original distinction into two por-
tions is marked by a transverse
line. To the second and third seg-
ments are attached both wings and
legs, whereas the first segment has
legs alone. The third segment
consists of seven pieces, which are
similar to those of the second. The
posterior wings are placed at the
anterior angles, and often occupy
the whole sides of the metattiorax.
A pergamenteous partition at the
posterior margin, which descends
in a perpendicular direction, bow-
ing in its middle towards the abdo-
men, separates the metathorax from
the abdomen.

METEO'RIC IRON. Colour pale steel-
grey ; occurs ramose, and dissemi-

nated in meteoric stones. Native,
or meteoric iron, is composed of
iron and nickel, the proportion of
nickel varying from one to nearly
ten per cent. In some specimens a
trace of cobalt has been discovered.
Pallas found a mass of native
iron 1680lbs. in weight, in Siberia,
which tradition stated to have
fallen from the air. Meteoric iron
is assuredly unlike any iron of
earthly origin, but it has been im-
itated by fusing iron with nickel.
METEO'RIC STONE. ) „ A 7.,
METE-OBITE. j See AerMe'
METEORO'LOGY. (from perewpa, mete-
ors, and \o<yos, a description, Gr.)
The study of the phenomena of the
atmosphere. It was not till the
17th century that any considerable
progress was made in investigating
the laws of meteorology. Previ-
ously to that period, the want of
proper instruments precluded the
cultivation of this science ; but the
discovery of the barometer and
thermometer in the 17th, and the
invention of accurate hygrometers
in the 18th century, supplied the
pre-existing defects, and enabled
philosophers to enter on meteorolo-
gical observations with accuracy
and facility.

MI'CA. (from micot to glisten.) This
mineral appears to be always the
result of crystallization, but is
rarely found in regular, well-defined
crystals. Most commonly it ap-
pears in thin, flexible, elastic
laminae, which exhibit a high pol-
ish and strong lustre. These
laminae have sometimes an extent
of many square inches, and, from
this, gradually diminish till they
become mere spangles, discoverable,
indeed, by their lustre, but whose
area is scarcely perceptible by the
naked eye. Mica is said to contain
forty-four per cent, of oxygen.
The laminae of mica are easily sep-
arated, and may be reduced to a
thickness not much exceeding the

MIC

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MIC

millionth part of an inch. Mica is
easily scratched with a knife, and,
commonly, even by the finger-nail.
Its surface is smooth to the touch ;
its powder is dull, usually grayish,
and feels soft. Its colours are
silver- white, gray, green, brown,
reddish, and black, or nearly black.
Specific gravity from 2 '50 to 2 '90.
"When rubbed on sealing-wax, it
communicates to the wax negative
electricity. Before the blow-pipe,
it fuses into a grey or black enamel.
Its constituents parts are, according
to Klaproth, silex 48*0, alumine
34-20, potash 8'75, oxide of iron
4'5, oxide of manganese 0'5. Ac-
cording to others, it is a compound
of silicium, potassium, magnesium,
calcium, &c., combined with oxy-
gen. Mica is one of the component
parts of granite, gneiss, and mica-
slate ; it occurs also in syenite,
porphyry, and other primary rocks.
To quartz and limestone it fre-
quently communicates a slaty
texture. It may always be dis-
tinguished from talc by the elasti-
city of its plates, talc being only
flexible and not elastic ; in its want
of unctuosity, and by its communi-
cating negative electricity to seal-
ing-wax. There are several varie-
ties, or sub-species; Jameson enu-
merates ten. Mica has been
employed, instead of glass, in the
windows of dwelling-houses. In
lanterns it is superior to horn,
being more transparent, and not so
easily injured by the flame. Mica
is a doubly refracting substance,
with two optic axes, along which,
light is refracted in one pencil.
MICA'CEOUS IKON OEE. A variety of
oxide of iron. This occurs generally
in amorphous masses, composed of
thin six-sided laminae. Colour
iron-black, or steel-grey. Lustre
metallic. Opaque. Feel greasy.
Hardness 5 to 7. Specific gravity
from 4'5 to 5'7. It is said to yield
nearly 70 per cent, of iron.

MI'CA SCHIST. | A metamorphic rock,

MI'CA SLATE, j composed of mica
and quartz ; it passes by insensible
gradations into clay-slate, and its
texture is slaty. Sometimes the
mica and quartz alternate, though
commonly they are more or less
intimately mingled, the mica
usually predominating.

MI'CAKELLE. The Finite of Kirwan.
See Finite.

MICROCHO'NCHAS CARBON A'RIUS. A mi-
croscopic spiral shell with but few
volutions, which when young touch
one another, but when old are
extended into a free tube, resem-
bling vermetus or vermillia. The
shell is sinistral. The lines of
growth are strong, somewhat irreg-
ular, deficient in parallelism, and
oblique to the axis of the tube.
Spiral striae may be perceived,
though but faintly. The Microchon-
chas Carbonarius is a fossil shell of
the coal measures.

MfcROpYLE. (from juicpos, small,
and 77-vXos, gate, Gr.) A botanical
term for the foramen in the perfect
seed ; this foramen is often visible,
as in the pea and bean.

MI'CROSCOPE. (from ytu/c/>o?, small,
and ffKOTrew, to behold, Gr. micro-
scope, Fr. microscopic, It.) A mi-
croscope is an optical instrument for
examining and magnifying minute
objects. Jansen and Drebell are
supposed to have separately in-
vented the single microscope, and
Fontana and Galileo seem to have
been the first who constructed the
instrument in its compound form.
The single microscope is nothing
more than a lens or sphere of any
transparent substance, in the focus
of which minute objects are placed.
The best single microscopes are
minute lenses ground and polished
on a concave tool ; but as the per-
fect execution of these requires
considerable skill, small spheres
have often been constructed as a
substitute. The most perfect single

MIC

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MIL

microscopes ever executed, of solid
substances, are those made of the
gems, such as garnet, ruby, dia-
mond, &c. Garnet is the best
material, as it has no double re-
fraction, and may be procured
perfectly pure and homogeneous.
When a single microscope is used
for opaque objects, the lens is
placed within a concave silver spec-
ulum, which concentrates parallel
or converging rays upon the face
of the object next the eye.

When a microscope consists of
two or more lenses, or specula, one
of which forms an enlarged image
of objects, while the rest magnify
that image, it is called a compound
microscope. The ingenuity of phil-
osophers and of artists has been
nearly exhausted in devising the
best forms of object-glasses and of
eye-glasses for the compound mi-
croscope.— Dr. Brewster.

MICROSCO'PIC. That may be seen only
by the aid of a microscope.

MICROSCO'PIC SHELLS. These are found
in prodigious abundance and of
such extreme minuteness, that in
their examination, and in the con-
sideration of them, our mental,
like our visual faculties, begin
rapidly to fail us when we attempt
to comprehend the infinity of little-
ness towards which we are thus
conducted. Of several species of
microscopic shells, five hundred
scarcely weigh a single grain, and
some are so exceedingly minute
that one thousand would scarcely
weigh a grain. In one ounce and
a half of stone from the hills of
Casciana, in Tuscany, Soldani ob-
tained 10,454 microscopic shells,
the remainder being principally
composed of comminuted fragments
of shells and spines of echini.

MICROTHE'RIITM. The name assigned
to a fossil genus of small anoplo-
therioid herbivores. Entire crania
of the Microtherium, from the
lacustrine calcareous marls of the

Puy- de-Dome are in the British
Museum.

MI'EMITE. A mineral, thus named
from having been found at Miemo,
in Tuscany. A green variety of
Dolomite, occurring in crystals,
and in masses with a radiated
structure.

MILK QUARTZ. The Milch Quartz of
Werner ; quartz hyalin laiteux of
Haiiy. A milk-white sub-species
of quartz, and distinguishable only
by its colour. It occurs massive.
Milk-quartz and rose-quartz are
considered by some mineralogists
as one and the same sub-species,
distinguished merely by their
colour, the one presenting a milky
appearance, while the other,
coloured by a minute quantity of
manganese, possesses a rose-red
colour, sometimes passing into a
flesh-red or crimson-red.
MI'LLEPEDE. } (millepeda, Lat. from
MILLIPEDE. ) miHet a thousand, and
pes, a foot.) Insects whose body
is generally cylindrical ; segments
half membraneous and half crusta-
ceous, each half bearing a pair of
legs; antenna3 seven-jointed, fili-
form, often a little thicker towards
the end. These are called milli-
pedes. The millipedes belong to the
necrophagous tribe, or those which
devour dead animals, or any
other putrescent substances. —
jffirby.

MILLE'PORA.. | (from mills, a thousand,
MI'LLEPORE. ) and porus, a pore.)
A genus oflithophytes or zoophytes
of various forms, having the surface
perforated with numerous small
pores or holes. A stony, internally
solid, polymorphous, ramose or
frondescent polypifer, pierced by
simple, not lamellated pores. The
pores cylindrical, and perpendicular
to the axis, or to the expansions of
the polypifer; for the most part
small, and sometimes not apparent.
— Parkinson. In millepores the
cells are more minute and close

MIL

[ 294 ]

M I

than in madrepores, and do not
exhibit any star-like radiations.

MILLE'POEITE. A fossil millepore.

MILI'OLA. | A genus of microscopic

MILLI'OLA. ) multilocular univalves,
not larger than a millet seed, with
transverse chambers, involving the
axis alternately, and in three
directions ; the opening small and
circular, or oblong, at the base of
the last chamber. Several species
are found to exist on our shores.

MI'LIOLITE. \ The fossil Miliola. So

MI'LLIOLITE. ) numerous are these
minute fossils in the neighbourhood
of Paris, that some species of them
form the principal part of the
masses of stone in some of the
quarries. The remains of such
minute animals as the milliola,
have added much more to the mass
of materials forming the earth's
crust than the bones of the mam-
moths, whales, and hippopotami.

MI'LLSTONE. Called also Burrhstone.
The Quartz .agathe molaire of
Haiiy; Silex meuliere of Brong-
niart. The exterior aspect of this
mineral is somewhat peculiar, being
full of pores and cavities, which
give it a corroded and cellular
appearance. It occurs in amor-
phous masses, above the marine
sand and sandstone. Sometimes
the mass is comparatively compact,
and the cavities small and not
numerous; but in all specimens
these cavities or cells are to be
found. Millstone is of a white or
greyish colour; sometimes with a
tinge of blue or yellow ; when
unmixed it is pure silex. It con-
tains no organic remains, and in the
order of superposition of the for-
mations in the neighbourhood of
Paris, it constitutes the ninth hor-
izontal bed, counting from the chalk
upwards. It is of great use for
making into millstones,, from which
circumstance it has obtained its
name.

MI'LLSTONE GRIT. The name given to

a silicious conglomerate, composed
of the detritus of primary rocks.
It has been thus named from some
of the strata having been worked
for millstones. It constitutes one
of the members of the carboniferous,
or mountain limestone group. The
millstone grit forms a bed of con-
siderable thickness in some situa-
tions, amounting to three or four
hundred feet; in others, it is of
very limited extent; and sometimes
it is wholly wanting. The mill-
stone grit is most commonly seen
under the form of a coarse-grained
sandstone, consisting of quartzose
particles of various sizes, (often
sufficiently large to give the rock
the character of a pudding-stone,)
agglutinated by an argillaceous
cement. This sandstone differs
from those which accompany the
coal measures, principally by its
greater induration. It sometimes
assumes a finer texture, in which
the mechanical structure becomes
less evident, and even passes into
a hard and solid cherty rock.

MI'LOSCHINE. The name given to a
hydrated silicate of alumina.

MIMOSI'TES. The name given to fossil
fruits belonging to the natural order
Mimosese.

MINERAL ADIPOCI'RE. A fatty bitu-
minous substance occurring in the
argillaceous iron ore of Merthyr,
in Wales. It is insoluble in water,
and fuses at a temperature of 160°.
When cold, it is inodorous; but on
being heated, gives out a bituminous
odour.

MI'NEHAL CAOU'TCHOUC. A variety of
bitumen, intermediate between the
harder and softer kinds. It some-
times much resembles India rubber
in its softness and elasticity, from
whence it derives its name, and,
like that, removes the traces of the
pencil, but, at the same time, it
soils slightly the paper. Colour
brown, reddish-brown, or hyacinth-
red. Specific gravity from 0.90 to

M I N

[295 ]

M I

1 '23. It burns with a bright flame,
emitting, during its combustion, a
bituminous odour. It occurs near
Castleton, in Derbyshire.

MI'NERAL CHA'RCOAL. A fibrous vari-
ety of non-bituminous mineral coal.

MiirEBALiZA'Tioff. The process of
converting into a mineral some
body not previously such.

MI'NEBALIZEB. That which converts
a substance into a mineral. Metals
are combined with oxygen, sulphur,
&c., by which their peculiar metal-
lic properties are more or less dis-
guised; in this case, the metal is
said to be mineralized, and the
oxygen or sulphur is termed the
mineralizer.

MI'NERALS. (minera, Lat. mineral,
Fr. minerdle, It.) Those bodies
which are destitute of organization,
and which naturally exist within
the earth or at its surface. The
term fossil is usually appropriated
to those organic substances which
have become penetrated by earthy
or metallic particles.

Minerals have been divided into
two kinds; simple, or homogeneous,
and compound, or heterogeneous.
Simple minerals appear uniform
and homogeneous in all their parts.
They do, in fact, usually contain
several different elementary sys-
tems; but these are so intimately
combined, and similarly blended,
in every part, as to exhibit a
uniformity of appearance.

Compound minerals more or less
evidently discover to the eye, that
they are composed of two or more
simple minerals, which either merely
adhere to each other, or, as is some-
times the case, appear imbedded
one in the other. Compound mi-
nerals are frequently aggregates or
rocks.

The description of minerals, and
their arrangement in systematic
order, must result from an investi-
gation of their properties. These
properties consist in certain rela-

tions which minerals bear to our
senses, or to other objects. Some
of them are discoverable by mere
inspection, or, at most, require
some simple experiment to be made
upon the mineral to ascertain its
hardness, structure, gravity, &c.,
while others cannot be observed
without a decomposition of the
mineral. All these properties are
usually called characters. We
hence have a twofold division of
the properties or characters of mi-
nerals into chemical and physical.
— Cleaveland.

MI'NERALOGY. That science, says
Cleaveland, which has for its object
a knowledge of the properties and
relations of minerals, and enables
us to distinguish, arrange, and
describe them.

Jameson defines mineralogy to
be that part of natural history
which makes us acquainted with
the properties and relations of mi-
nerals. It is divided, according
to that professor, into two grand
branches, namely, mineralogy, pro-
perly so called, and geology. Mi-
neralogy treats of the properties
and relations of simple minerals;
while geology considers the various
properties and relations of the at-
mosphere, the waters of the globe,
the mountain rocks, or those mi-
neral masses of which the earth is
principally composed, and the form,
density, heat, electricity, and mag-
netism of the earth.

The history of the materials of
the crust of the globe, their pro-
perties as objects of philosophical
enquiry, and their application 'to
the useful arts and the embellish-
ments of life, with the characters
by which they can be certainly
distinguished one from another,
form the object of mineralogy,
taken in its most extended sense.

Mineralogy is a science of such
interest, that it would be much to
be regretted if its real objects and

M I N

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M I

tendency were misunderstood, or
suffered to degenerate into an avi-
dity merely for the collecting of
what is brilliant or rare. To the
attainment of the science of geology,
which is intimately connected with
agriculture and the arts of life, that
of mineralogy is essentially requisite.
The study of mineralogy, therefore,
does not include only a knowledge
of the more rare and curious mi-
nerals : there is nothing in the
mineral kingdom too elevated or
too low for the attention of the
mineralogist, from the substances
composing the summits of the lofti-
est mountains, to the sand or gravel
on which he treads.

Ey the study of what, in oppo-
sition to the term aggregated rocks,
may be termed simple minerals,
the mineralogist becomes enabled
to detect the substance with which
he holds acquaintance by itself,
when aggregated with others in a
mass ; and thus he becomes qualified
for the more difficult and more im-
portant study of the science of geo-
logy, which embraces a knowledge
of the nature and respective posi-
tions of the masses and beds com-
posing mountains, and, indeed, of
every description of country, whe-
ther mountainous or otherwise.

There is no branch of science
which presents so many points of
contact with other departments of
physical research, and serves as a
connecting link between so many
distant points of philosophical
speculation as this. Nor, with the
exception of chemistry, is there
any which has undergone more
revolutions, or been exhibited in a
greater variety of forms. To the
ancients it could scarcely be said to
be known at all, and up to a compar-
atively recent period, nothing could
be more imperfect than its descrip-
tions, or more inartificial or un-
natural than its classification. The
Arabian writers, however, in the

middle ages appear to have culti-
vated mineralogy with some suc-
cess; the first foundation of a
rational arrangement of minerals
was laid by Avicenna at the close
of the tenth century. It was only
when chemical analysis had ac-
quired a certain degree of precision
and universal applicability, that
the importance of mineralogy as a
science began to be recognized, and
the connection between a stone and
its ingredient constituents brought
into distinct notice. The arrange-
ment of simple minerals has always
been a subject of controversy with
mineralogists ; and the discussions
to which it has given rise have
materially contributed to the ad-
vancement of our knowledge of the
natural and chemical history of
minerals. Eerzelius contends for
the chemical arrangement, accord-
ing to which the species are grouped
in conformity with their chemical
composition and characters. Wer-
ner rejects the pure chemical, and
adopts the mixed method, in which
the species are arranged and deter-
mined according to the conjoined
external and chemical characters.
The writers of the Wernerian school
usually divide mineralogy into the
five following branches; namely,
oryctognosy, chemical mineralogy,
geognosy, geographical mineralogy,
and economical mineralogy. Of
late years, the arrangement accord-
ing to external characters alone
(named the natural history system)
has been advocated by Mohs.
Among the external characters of a
stone, none were, however, found
to possess that eminent distinctness
which the crystalline form offers ;
a character in the highest degree
geometrical, and affording the
strongest evidence of its necessary
connection with the intimate con-
stitution of the substance. The
full importance of this character
was, however, not felt until its

M I

[297 ]

MIT

connection with the texture or
cleavage of a mineral was pointed
out, and, even then, it required
numerous and striking instances
of the critical discernment of Baiiy,
and other eminent mineralogists, in
predicting from the measurements
of the angles of crystals which had
heen confounded together, that
differences would be found to exist
in their chemical composition, all
which proved fully justified in their
result before the essential value of
this character was acknowledged.
The invention of the goniometer
by Carangeau, and subsequently
the reflecting goniometer by Dr.
"Wollaston, which last has been
improved by Sang, gave a fresh
impulse to that view of mineral-
ogy which makes the crystalline
form the essential or leading char-
acter, by putting it in the power of
every one, by the examination of
even the smallest portions of a
broken crystal, to ascertain the
character on which the identity of
a mineral in the system of Hauy
was made to depend. Mineralogy,
however, as a branch of natural
history, remains still distinct from
either optics or crystallography.
But whatever progress may have
hitherto been made in mineralogical
pursuits, every new advance has
opened a wider and more interesting
prospect. Mineralogy is in reality
essential to the geologist; it is
the very alphabet to the older
rocks, and it is probably to be at-
tributed in great measure to the
want of due preparation for the
study of these rocks, by an intimate
acquaintance with minerals in the
simple state, that the primary and
transition tracts have been investi-
gated in a far less degree than
those of a newer origin. The
science is still in its infancy,
and in many of its paths can
proceed only with a faultering
and uncertain step. — Herschell.

Jameson. Cleaveland. Phillips.

MI'NITJM:. (minium, Lat.) A red
oxide of lead. Minium is of a
bright scarlet ; it occurs in a loose
state, or in masses, composed of
flakes with a crystalline texture.
It is found in the lead mines of
Westphalia. It is used in glass-
making, enamelling, and some
other arts.

MI'OCENE. | (from yiietW, less, and

MEI'OCENE. j KCLIVOS, recent, Gr.)
The name given by Sir C. Lyell to
a subdivision of the tertiary strata.
He says, " the European tertiary
strata may be referred to four suc-
cessive periods, each characterized
by containing a very different pro-
portion of fossil shells of recent
species." These four periods he
names, Newer Pliocene, Older Plio-
cene, Miocene, and Eocene. The
Miocene period has been found to
yield from eighteen to twenty-five
per cent, of recent fossils. This
was the result of an examination
of 1021 fossil species by M. De-
shayes. Many shells belong ex-
clusively to the Miocene period.
The Miocene strata are largely
developed in Touraine, and in the
South of France near Bordeaux, in.
the basin of Vienna, and other
localities. The miocene strata con-
tains an admixture of the extinct
genera of lacustrine mammalia of
the Eocene series, with the earliest
forms of genera which exist at the
present time. In regard to the
relative position of the strata, they
underlie the older Pliocene, and
overlie the Eocene formations,
when any of these are present.

MI'TRA. A genus of shells belonging
to the Columellaria in Lamarck's
arrangement. It is a subfusiform
univalve, with a long, pointed, tur-
retted apex, a notched base, and
no canal. Covered with an epi-
dermis of a light brown colour.
The columella is plicated ; the
inferior plicee being the smallest.

Q Q

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[ 298 ]

M 0 L

Mitres are found both fossil and
recent.

MO'CHA STONE. (from Mocha, in
Arabia.) The quartz agathearboris£
of Hau'y; called also dendrite
agate. A variety of agate, con-
taining in its interior very beautiful
delineations of leafless shrubs, trees,
&c., of a brown or dark colour.
These dendritic appearances are
supposed to be produced by the
nitration of the oxides of iron
and manganese into the fissures of
the agate. Mocha stones resemble
those agates which are found on
the Sussex coast called dendracliates.

MODI'OLA. (from modulus, Lat. a
little measure.) A genus of shells
belonging to the family Mytilacea.
A transverse inequilateral bivalve.
The modiola is a littoral shell,
moored to rocks, stones, and shells.
One species, modiola discors, floats
free, enveloped in its own silky
byssus. Fossil species have been
found in the neighbourhood of
Paris, and in this country.

MO'LAB. (from mola, a mill, Lat.
molai/re, Fr.) A grinder- tooth.
The large double teeth are called
molar teeth, or grinders ; these are,
however, subdivided according to
their different forms ; thus, those
with two fangs are called bicuspid,
or false molar teeth. The posterior
molar teeth are differently shaped
in carnivorous animals, being raised
into sharp, and often serrated,
edges, having many of the proper-
ties of cutting teeth. In insecti-
vorous and frugivorous animals,
their surface presents prominent
tubercles, either pointed or round,
for pounding the food; while in
graminivorous quadrupeds they are
flat and rough, for the purpose
simply of grinding.

MOLA'SSE. (from mollis, soft, Lat.)
The name given to a soft green
sandstone found in Switzerland ;
one of the most recent of the ter-
tiary deposites. In the Molasse of

Switzerland there are many depo-
sites affording sometimes coal of
considerable purity.

Until the place of the molasse in
the chronological series of tertiary
formations be more rigorously de-
termined, the application of this
provincial name to the tertiary
groups of other countries must be
very uncertain, and it will be desi-
rable to confine it to the tertiary
beds of Switzerland. — Lycett.

MO'LECULE. (moUcule, Fr. petite partie
d'un corps.) A minute particle of
a mass or body, differing from
atom, inasmuch as it is always a
portion of some aggregate. The
ingredients of granite, and of all
other kinds of crystalline rocks,
are composed of molecules which
are invisibly minute, and each of
these molecules is made up of still
smaller and more minute molecules,
every one of them combined in
fixed and definite proportions, and
affording, at all the successive
stages of their analysis, presump-
tive proof that they possess deter-
minate geometrical figures.

MoLLifscA. (mottusca, a nut with a
soft shell, Lat.) According te the
arrangement of Cuvier, the second
great division of the animal king-
dom. This he subdivided into six
classes, namely, Cephalopoda, Pter-
opoda, Gasteropoda, Acephala, Bra-
chiopoda, and Cirrhopoda. A vast
multitude of species, possessing in
common many remarkable physio-
logical characters, are comprehended
in this great division. In all, as
their name imports, the body is of
soft consistence ; and it is enclosed,
more or less completely, in a mus-
cular envelope, called the mantle,
composed of a layer of contractile
fibres, which are interwoven with
the soft and elastic integument.
Openings are left in this mantle
for the admission of the external
fluid to the mouth and to the respi-
ratory organs, as well as for the

M 0 L

protrusion of the head and the
foot, when these organs exist. But
a large proportion of animals com-
prised in this class are acephalous,
that is, destitute of a head, and the
mantle is then often elongated to
form tubes, occasionally of consi-
derable length, for the purpose of
conducting water into the interior
of the body.

The general form of the body,
and the kind of motions it performs,
vary more in the molluscous than
in the articulated classes of animals,
and we observe a corresponding
diversity in their active organs of
motion. The whole skeleton, the
solid frame-work of the body, de-
stined to give strength, form, and
support to the entire machine, dis-
appears in the class of mulluscous
animals. In the molluscous clas-
ses there appear much greater
variety, diversity, and want of
symmetry in the whole muscular
system. Many of the lower mol-
luscs are fixed by long peduncles
at the bottom of sea; some, as the
Km aces, creep on the surface of the
dry land ; the pteropods swim at
the surface of the ocean, where the
janthinse hang suspended by floats ;
the naked cephalopods bound from
the surface, and the pholades are
fixed deep in cavities of rocks at
the bottom ; the oyster is fixed to
the rock, while the clam skips
to and fro by the flapping of
its shells; the pinna is anchored
to the bottom by its strong
byssus, while the cardium swims
along the still surface, suspended
by its concave expanded foot.
So that altthough none of these
animals have wings to fly through
the air, or jointed legs to creep
upon the earth, or spines to oar
them through the sea, they possess
the means of almost every kind of
motion, from the vibratile cilia of
the fixed corals to the hands and
feet of the finny tribe. The circu-

[ 299 ] M 0 L

lation of the mollusca is always
double; that is, their pulmonary
circulation describes a separate and
distinct circle. Their alimentary
canal hardly ever passes straight
through their body; nor is the
anus terminal, as in most of the
articulata. Their digestive cavities
are more numerous and capacious,
the intestine is more lengthened
and convoluted, and all the as-
sistant glandular organs are de-
veloped on a higher plan, and are
more constant throughout the
classes. The lowest of the mol-
luscous classes, the tunicated
animals, shut up in the interior of
a cartilaginous, more or less elastic,
and biforate tunic, have no pre-
hensible or masticating organs con-
nected with their mouth. The
mouth, in fact, is placed at the
bottom of the respiratory sac, and
appears to be destitute even of those
tentacula, appendices, or lips,
which are so much developed, and
so various in their forms, in the
conchiferous animals.

In the mollusca we have the only
instance in creation, of a unvpede
structure, but this one foot answers
every purpose of a hand or leg ; it
spins for the bivalves their byssus,
is used by others as a trowel, by
others as an augur, and by others
for other manipulations, and is
generally their sole organ of loco-
motion ; from its soft and flexible
substance, it can adapt itself to the
surfaces on which it moves, and by
the slime that it copiously secretes
lubricates them to facilitate its
progress. It is probable that the
foot may be also employed by these
animals as an organ of touch. In
the nervous system of mollusca, the
ganglia have a circular arrange-
ment. The transition series afford
examples of several families and
many genera of mollusca, which
appear at that period to have been
universally diffused over all parts

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L 300 ] M 0

of the world. Some of these, as
the orthoceratite, spirifer, and pro-
ducta, became extinct at an early
period in the history of stratified
rocks, whilst others as the tere-
bratula and nautilus, have con-
tinued through all formations to
the present time. — Cumer. Grant.
Kirty. Roget.

MOLLTJSCOID'EA. The third class of
the sub-kingdon Mollusca : this
class comprises three orders, name-
ly, Brachiopoda, Polyzoa, and
Ascidioida, or Tunicata.

MOLLTJ'SCOUS. Animals belonging to
the division mollusca, or soft, in-
vertebral, inarticulate animals ;
often protected by a shell.

MOLLTJ'SKITE. The soft bodies of the
testaceous mollusca often occur in
a fossil state, changed into a brown
carbonaceous substance, to which
Dr. Mantell assigned the above
name.

MOLY'BDATE OF LEAD. The plomb
molybdate of Haiiy; pyramidaler
blaibaryt of Mohs. Yellow lead
ore. It is of a yellow colour,
varying from lemon yellow to yel-
lowish brown. Occurs crystallized
and massive. Its specific gravity
from 6-5 to 6-9. Fracture uneven,
or imperfectly conchoidal. Slightly
translucent, especially at the edges.
Before the blow-pipe it decrepitates,
and fuses into a dark coloured mass.
It consists of oxide of lead 58,
molybdic acid 38, oxide of iron, 2.
It is found at Bleyberg, in Car-
inthia, and in Mexico, in compact
limestone.

MOLYBDE'NA. A mineral of a lead-
grey colour, occurring in thin flexi-
ble leaves.

MOLYBDE'NTTM. (from fiokvpSaiva, Gr. )
A metal discovered by Hielm in
1782; externally of a whitish yel-
low colour ; fracture whitish grey :
sp. gr. about 8-6. It is nearly
infusible. It is obtained from the
mineral molybdena in small grains,

agglutinated together in brittle
masses.

MO'NAD. (from povas, Gr. an atom,
monade, Fr.) The recent observa-
tions of Professor Ehrenberg have
brought to light the existence of
monads, which are not larger than
the 24,000th of an inch, and which
are so thickly crowded in the fluid
as to leave intervals not greater
than their own diameter. Hence
he has made the computation that
each cubic line, which is nearly
the bulk of a single drop, contains
500,000,000 of these monads; a
number which equals that of all
the human beings on the surface
of the globe in one drop of fluid.
Monads, which are the smallest of
all visible animalcules, have been
spoken of as constituting "the ulti-
mate term of animality."

MoNA'tfPKiA. (from /AoVos, one, and,
avfjp, a man, Gr.) The first class
of plants in Linnasus's artificial
system. The plants of this class
have only one stamen; it is a small
class, and contains only two orders.

MONI'LIFORM. (from monile, a neck-
lace, and forma, form, Lat.) Ee-
sembling a necklace

MO'NITOB. (monitor, Lat.) A genus
of lizards or saurians, species of
which are found both fossil and
recent; the recent inhabit the
tropics. Cuvier places this genus
in the family Lacertinida. The
monitors frequent marshes, and the
banks of rivers, in hot climates;
they have received their name from
a common but silly notion that
they give warning of the approach
of crocodiles and caymans by a
whistling noise. One species, the
Lacerta nilotica, devours the eggs
of crocodiles. Fossil remains of
the monitor have been discovered
in the strata of Tilgate Forest, in
Sussex.

MONOCOTYLE'DON. (from /toVos, one,
and Korv\r]Swv, a seed lobe, Gr.)

M 0 IT

301

MOB.

A plant which has only one coty-
ledon or seed-lobe.

MONOCOTYLE'DONOUS. Plants, the seeds
of which have either only one
cotyledon, or if more, those alter-
nate on the embryo, are called
monocotyledonous ; grasses, lilies,
aloes, and palms, are examples.
Monocotyledonous plants may be
at all times recognised, from the
circumstance of the veins of their
leaves being parallel, while those
of dicotyledonous plants are reti-
culated.

MONOS'CIA. (from povos, one, and
oiKia, a house, Gr.) The twenty-
first class of plants in the ar-
tificial system of Linnaaus. In
this class of plants the stamina
and pistils are in separate flowers,
but growing on the same individual
plant. The orders in this class
depend upon the circumstances of
their male flowers, and are nine or
ten in number.

MONOB'CTOTJS. Plants belonging to the
class Monoecia.

MO'NODON. (from /tovd^ove, Gr. hav-
ing one tooth.) The sea unicorn,
or narwhal ; distinguished by its
long tusk, or tusks, for there are
sometimes two, extended in a hori-
zontal direction. The Monodon
belongs to the order Cetacea, class
Mammalia.

MONODO'NTA. A genus of univalve
shells separated from Trochus on
account of a tooth-like process
which it forms at its base. Several
fossil species are known in the
oolitic formations of England. —
Lycett.

MONOPE'TALOUS. (from ^toVos, one,
and 7rera\ov} a petal, Gr.) Flowers
are so called which consist of only
one leaf or petal; or when the
leaves whieh compose the corolla
are united by their edges ; the con-
volvulus, honeysuckle, &c., are
examples.

MONOPHY'LLOUS. (from /toVos, sole,
and 0v\Xoj/, a leaf, Gr.) Having

one leaf only, or formed of one
leaf; applied to calices consisting
of not more than one leaf.

MONOSE'PALOTJS. A term applied to the
calyx of a flower, when the sepals
which compose it are united by
their edges : the pink, convolvulus,
henbane, &c., are examples.

MONOTHA'LAMOUS. (from ^oVos, single,
and tfaXayttos, a chamber, Gr.)
Shells whose chamber is undivided
by partitions; these are termed
unilocular, or monothalamous : the
argonaut is an example.

MO'NOTREME. The Monotremes form
Cuvier's third tribe of Edentata,
comprising two genera, namely,
Echidna and Ornithorhynchus.
They are foand only in New Hol-
land. The Monotremes seem con-
nected with the birds ; one genus,
the ornithorhynchus, having a
mouth resembling the bill of a duck,
and being almost web-footed; it
has also been stated to be oviparous.
The Monotremes have no marsupial
pouch. They suckle their young
from a mammary orifice. In the
classification of some authors, Mon-
otremata constitutes the second
order of the sub-class Implacen-
talia.

MOO'NSTONE. A variety of felspar,
called also adula/ria, possessing a
silvery or pearly opalescence.
Moonstone is transparent and trans-
lucent : colour white, with some-
times a tinge of yellow, green, or
red. When held in certain posi-
tions, its surface is iridescent. It
occurs massive, and in crystals. It
is found in the fissures and cavities
of granite, gneiss, &c.

MORA'INE. An accumulation of sand,
stones, or debris, found upon ice-
bergs, glaciers, &c. In front of
glaciers there is usually a pile of
rubbish, composed of pieces of rock,
earth, and trees, which they have
forced forward, known in Switzer-
land by the name of moraine. If
there be a line of moraine some

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302 ]

M 0 U

distance from the front of the gla-
cier, it is considered that the glacier
has retreated to the amount of that
distance ; but if there be no other
than that which the glacier imme-
diately drives before it, it is con-
sidered to be on the increase.
HORO'XITE. A sub-species of apatite,
occurring in crystals, of a brownish
or greenish-blue colour : found in
Norway, in primary rocks.

\ "The Mososaurus,"
> says Buckland, "has
) been long known by
the name of the Great Animal of
Maestricht, occurring near that
city, in the calcareous freestone,
which forms the most recent deposit
of the cretaceous formation. A
nearly perfect head of this animal
was discovered in 1780, and is now
in the museum at Paris. This
celebrated head, during many years,
puzzled the most skilful naturalists;
some considered it to be that of a
whale, others of a crocodile; but
its true place in the animal king-
dom was first suggested by Adrian
Camper, and, at length, confirmed
by Cuvier. By their investigations,
it is proved to have been a gigantic
marine reptile, most nearly allied
to the monitor. Some vertebrae of
the mososaurus have been disco-
vered in the upper chalk near
Lewes, in Sussex ; these have the
body convex posteriorly, and con-
cave anteriorly, and were one hun-
dred and thirty-three in number.
It had four paddles instead of legs.
Teeth of the mososaurus have been
discovered in the green-sand of
Virginia. Portions of jaws, with
teeth of the mososaurus, may be
seen in the British Museum.
The mososaurus was a reptile,
holding an intermediate place
between the monitor and iguana,
about twenty- five feet long, and
furnished with a tail of such con-
struction as must have rendered it
a powerful oar, enabling the animal

to stem the waves of the ocean, of
which Cuvier supposes it to have
been an inhabitant."

" From the lias upwards, to the
commencement of the chalk forma-
tion, the ichthyosauri and plesiosauri
were the tyrants of the ocean ; and
just at the point of time when their
existence terminated, during the
deposition of the chalk, the new
genus mososaurus appears to have
been introduced, to supply for a
while their place and offices, being
itself destined, in its turn, to give
place to the cetacea of the tertiary
periods."

Moss A' GATE. A kind of agate which
on being cut and polished, presents
delicate vegetable ramifications of
different shades, resembling small
filaments of moss, or fibres of roots,
irregularly interwoven. It has
been suggested by some authors
that these filaments may be really
mosses enveloped in the agate.

Moss FIR. The name given to a
certain kind of wood frequently
found in peat mosses or bogs. It
much resembles in its colour and
general external appearance, ordi-
nary decayed fire- wood; but on
examination it appears that the
fibre of the wood is strongly im-
bued with resin, and that all its
interstices are filled with resinous
matter. It is so highly inflam-
mable as to be employed not only
as fuel but as torches.

MOTHER OF COAL. In many coals
little flakes of mineral charcoal
occur, retaining that part of the
vegetable structure called the vas-
cular tissue. They are called by
the colliers " mother of coal."

MOULD. (muld, Goth, mold, Seel.
mold, Sax. mul, Dan. mull, Germ.
Dr. "Webster says the orthography
of this word is incorrect, and that
it should be written mold : so far
as the etymology of the word is
concerned, perhaps Webster is cor-
rect, but, assuredly, custom war-

M 0 U

303

M 0 IT

rants our writing it mould.) The
name given to that superficial ac-
cumulation of various substances
which lies upon the surface of the
dry land, and covers the rocks
below.

"The process," says Dr. Buck-
land, " is obvious whereby even
solid rocks are converted into soil
fit for the maintenance of vegetation,
by simple exposure to atmospheric
agency; the disintegration produced
by the vicissitudes of heat and cold,
moisture and dryness, reduces the
surface of almost all strata to a
comminuted strata of soil, or mould,
the fertility of which is usually in
proportion to the compound nature
of its ingredients."

MOUNTAIN COEK. (The Berg kork
of Werner; Suber montanum of
Kirwan ; Asbeste suberiforme of
Brongniart.) A white or grey
variety of asbestos, to which the
name of mountain cork has been
given from its extreme lightness;
sp. gr. from 0'68 to 0*99, con-
sequently so light as to swim in
water. Its structure is fibrous;
the fibres promiscuous and inter-
woven. Its constituents are silex
56-2, magnesia 26-1, lime 12'7,
iron 3*0, alumine 20. It occurs
in Prance and Saxony.

MOU'NTAIN BLUE. A species of blue
malachite or blue copper. The
Cuivre carbonate bleu of Haiiy;
Kupfer lazur of "Werner. Carbon-
ate of copper. The characteristic
colour of mountain blue is azure-
blue, often exceedingly beautiful
and splendent. Occurs regularly
crystallized in scopiform and stel-
lular concretions, radiated, and also
curved lamellar. When rubbed on
paper, it leaves a light blue streak.
Sp. gr. from 3'20 to 3*60. It dis-
solves with effervescence in nitric
acid. It is scarcely fusible alone,
but with borax, to which it com-
municates a fine green, it yields a
globule of copper. Its constituents

are copper 66, carbonic acid 18,
oxygen 8, water 2.
MOU'NTAIN LI'MESTONE. (The Calcaire
carbonifere, Calcaire anthraxifere,
and Calcaire de transition of the
French ; the Kohlenkalk, and
Ueberganskalk of the Germans.
Conybeare proposed to designate
this rock "Carboniferous Limstone."
By some authors it has been termed
metalliferous limestone, from its
mineral riches; by others, entro-
chal or encrinal limestone, from its
organic remains : it has also been
proposed to designate it by the
Wernerian name, "first flcetz for-
mation.") A series of marine
limestone strata, whose geological
position is immediately below the
coal measures and above the old red
sandstone. To this formation the
French have given the name of Cal-
caire de transition. Mountain lime-
stone is one of the most important
calcareous rocks in England and
Wales, both from its extent, the
thickness and number of its beds,
the quantity and variety of its
organic remains, and its richness
in metallic ores, particularly of
lead. ID Derbyshire, where the
different beds of limestone have
been pierced through by the mi-
ners, the average thickness of the
three uppermost is about 160 yards;
the series is said to exceed, in some
instances, 1000 feet: the beds are
separated by beds of trap or basalt,
resembling ancient lavas. The
limestone is generally sufficiently
hard to bear a polish, and forms
what is denominated marble, of
considerable beauty. The moun-
tain limestone formation occupies
an immense tract in Northumber-
land, Durham and Yorkshire, from
which country it runs out into a
curve to encircle on the north, and
partially on the south, the group of
Cumbrian slate mountains. It also
appears in great force in Derby-
shire, ranges through Flint and

M 0 U

[304]

M

Denbigh, to St. Orme's head and
Anglesea; shows slightly round
the Clee hills in Shropshire; and
presents picturesque cliffs on the
Wye, near Monmouth. The moun-
tain or carboniferous limestone may,
according to Mr. "Weaver, be con-
sidered as the prevalent rock in
Ireland ; all its counties, with the
exception of Antrim, Derry, and
Wicklow, being more or less com-
posed of it, and in some instances
it attains a thickness of 1700 feet
and upwards. The prevailing char-
acteristic organic fossils are madre-
pores and encrinites ; of the latter,
some of the upper beds appear to be
almost entirely composed. Moun-
tain limestone is generally almost
a pure carbonate of lime; its purest
beds appearing to contain about 96
per cent, of calcareous matter ; but
by the admixture of other ingre-
dients, it often passes into magne-
sian limestone, ferruginous lime-
stone, bituminous limestone, and
fetid limestone. It is a prevailing
character of the mountain limestone
to be full of caverns and fissures.

MOT/NTAIN LEATHER. (Bergleder ;
corium montanum; cuir de mon-
tagne.) A variety or sub-species
of asbestus, the same as Mountain
Cork, which see.

MOTJ'NTALN MEAL. (The Bergmehl of
Eabbroni.) This singular mineral,
says Phillips, was found in the
form of a bed by Fabbroni, at Santa
Piora, between Tuscany and the
Papal dominions ; it is manufac-
tured into bricks, so light as to
swim in water. Klaproth gives
as its analysis, silica 79, alumina
5, oxide of iron 3, water 12.

MOU'NTAIN SOAP. A mineral, a variety
of bole, of a black or blackish-brown
colour. It is massive, dull, smooth
and soapy to the touch, and adheres
strongly to the tongue. It writes
on paper. Its constituents are si-
lex 44, alumine 26-2, oxide of iron
8, lime 0.5, water 20-10. It

occurs in secondary rocks of the
trap formation in the Isle of Skye,
and in Poland.

MOUNTAIN WOOD. The berg-kolz of
Werner; asbesteligniformofHaiiy;
le bois de rnontagne of Brochant.)
A subspecies of asbetus of a wood-
brown colour, occurring massive
and in plates : it has somewhat the
aspect of wood, and is occasionally
so hard and compact as to resemble
petrified wood. It is infusible
before the blow-pipe, according to
Jameson, but Phillips states that it
fuses into a black slag, and is about
twice the weight of water.

MT/CRONATE. (mucronatus, Lat.
pointed.)

1. In entomology, when from an
obtuse end a fine point suddenly
proceeds.

2. In botany, when a small point
terminates an entire leaf, aa in the
vetch, house-leek, &c.

3. In conchology, when a shell
terminates in a sharp rigid point.

MO'YA. The name given by the na-
tives of South America to the mud
and slime ejected from volcanos
during the eruptions.

MTJLA'TTOE. An arenaceous stone,
with a calcareous cement, deriving
its name from its speckled appear-
ance, which is caused by numerous
disseminated spots of green earth.
It occurs in Ireland, and agrees
altogether in its characters and
fossils with the green sandstone.

MTJLTISPI'RAL. (from multus, many,
and spira, a spire, Lat.) In con-
chology, a term for a shell whose
spire consists of many whorls; also
an operculum of many volutions.

MULTILO'CTJLAR. (from multus, many,
and loculus, a chamber or shell,
Lat.) A term applied to shells
containing partitions, which divide
them into several chambers. Or-
thoceratites, baculites, hamites,
scaphites, belemnites, &c., are all
multilocular shells; the argonaut, or
paper natilus, is a unilocular shell.

M U L

[ 305 ]

M Y A

MU'LTIVALVE. (from multus, many, '
and valvce, valves, Lat.) Some of
the mollusca have, in addition to
the two principal valves, small
supplementary pieces of shell ;
these have been comprised in the
order of multivalves.

MU'NDIC. Iron or arsenical pyrites,
which strike fire with amazing
facility. The term, says Dr. Paris,
seems to be derived from this
quality.

MT/RCHISONIA. A genus of fossils of
the Silurian formation.

MU'RCHTSONITE. A mineral, thus named
by Mr. Levi, in honour of Sir R.
' Murchison. Its constituents are
silica 68*10, alumina 16*6, potash
14-8. It occurs near Dawlish ; it
is a variety of felspar.

MtfREX. (murex, Lat. murex, Pr.)
A genus of shells. Animal a
limax: shell univalve, spiral, rough,
with membraneous sutures ; aper-
ture oval, ending in an entire
straight, or slightly ascending
canal. The murex is an inhabitant
of the ocean, found at depths
varying from five to twenty-five
fathoms, on different bottoms.
These shells, besides their long chan-
nelled beaks, are remarkable for the
beauty and variety of their spines.
Murices, or rock-shells, were in high
esteem from the earliest ages, on
account of the dye that some of
them yielded ; cloths dyed with it
bearing a higher price than others.
More than one species yielded a
dye; one, according to Bochart, a
glaucous or azure colour ; the
other, a purple. Different species
of fossil murex are found in the
London clay andintheBognor sand-
stone, and Lamarck describes many
species found in the neighbourhood
of Paris.

MTJ'REX CONTRA'RIUS. The reversed
whelk, now more commonly known
as Fusus contrarius, is a sinistral
shell, and is found most abundantly

in the crag formation, of which it
appears characteristic.

MTfRiAdTE. A name given to anhy-
drite, by Klaproth. See Anhy-
drite.

MTT'BICA.TED. (murwatus,~Lat.) Clothed
with sharp rigid points ; beset with
short erect spines.

MTJ'RICITE. The fossil murex.

MFSA'CEA. A family of tropical mon-
ocotyledonous plants, including the
banana and plaintains.

MT/SCLE BAND. The name given to a
bed of ironstone, found about the
middle of the coal series in Derby-
shire, and thus named from its
containing a very large number of
different species of mytili.

MTJ'SCHEL-KALK. (from muschel, shell,
and Icalk, lime or chalk, Germ.) A
compact hard limestone, of a grey-
ish colour, found in Germany. It
belongs to the red sandstone group.
The muschel- kalk of Germany
cannot be considered to have any
precise equivalent among the Eng-
lish strata, and indeed would appear
to be unknown in England and the
north of Germany. It occasionally
is met with of sufficient hardness
to be employed as marble. In
Bavaria and Wurtemburg the mus-
chel-kalk is interposed between the
red sandstone, on which it rests,
and the variegated marls which lie
over it, and with which, at the
junction, it alternates. The mus-
chel-kalk abounds in organic
remains.

MUSCLE-BIND. The name given to a
stratum of imperfect ironstone and
indurated shell, found in the
Derbyshire and Yorkshire coal
fields.

MU'SITE. | A mineral, thus named

MtfssiTE. ) from Mussa, in Pied-
mont, where it occurs. It is a
white, or pale green, variety of
augite.

MY' A. (from fwtav, a muscle, Gr.)
A genus of bivalves belonging to
the family Myacidse. Animal an

M Y A

306 ]

M T T

ascidia. Shell transverse, oval,
thick, gaping at both ends; liga-
ment internal. Hinge with broad,
thick, strong, patulous tooth, sel-
dom more than one, perpendicular
to the valve, and giving attachment
to the ligaments.

MY'LIOBATES. A genus of fossil Rays.
They are abundant in the London
clay and in the crag.

MT'OLOGY. (from fiv$, '[wo?, a mus-
cle, and \oryov, discourse.) A
description of the muscles.

MYO'POBA. A genus of bivalve con-
chifera, established by Lea, belong-
ing to the family Arcacea.

MYBIAN'ITES. A genus of the !N"erei-
dina of Mac Leay; body linear,
very narrow, and formed of very
numerous segments, with indistinct
feet and short cirri. One species,
Myrianites Mac Leaii, so named by
Sir E. Murchison, and described in
his Silurian system, has been
found in the older rocks.

Mroco'NCHA. A genus of fossil bi-
valve shells, belonging to the
Cardiacea ; they are oval, equi-
valve, oblique; the umbones are
terminal, the hinge has an external
ligament, and an oblique elongated
tooth in the left valve, the general
form of this shell is that of My tilus ;
the only known species is the M.
Crassa of the Great and Inferior
Oolite.

MTETA'PODA. } (from fivpia, ten thous-

MY'RIAPODS. ) and, and TTOVS, nodo?,
a foot, Gr.) A class of insects,
commonly called Centipedes, pos-
sessing a number of feet, from six
to some hundreds. The Myriapoda,
in general, resemble little serpents,
or Nereides, their feet being closely
approximated to each other through-

out the whole extent of the body.
Myriapods exhibit the following
general characters. Animal under-
going a metamorphosis by acquir-
ing in its progress from the egg to
the adult state several additional
segments and legs. Body without
wings, divided into numerous pedi-
gerous segments, with no distinc-
tion of trunk and abdomen. Head
with a pair of antennae ; two com-
pound eyes ; a pair of mandibles ;
under-lip connate with the maxillaD.
Myriapoda constitutes the second
class of the sub-kingdom Annulosa,
and comprises two orders, Chilopoda
and Chilagnatha.

MYTILA'CEA. In Cuvier's arrange-
ment, the second family of the
order Acephala Testacea. All be-
longing to this family are bivalves,
having a foot which they use in
crawling. Mytilacea comprises,
in Lamarck's system, Modiola,
Mytilus, and Pinna.

MI'TILUS. (mytilw, Lat.) A genus
of the family Mytilacea. The
muscle. A rough, longitudinal,
bivalve; with equal, convex, anil
triangular valves; the anterior, and
longest side of the shell, allowing
passage of the byssus. The Mytilus
is a littoral shell, moored to rocks,
stones, crustaceans, &c. The foot
of the Mytilus edulis, or common
muscle, can be advanced to the
distance of two inches from the
shell, and applied to any fixed
body within that range. By at-
taching the point to such body, and
retracting the foot, this animal
drags its shell towards it ; and by
repeating the operation successively
on other points of the fixed object,
continues slowly to advance. Some
Mytili produce pearls.

NAG

[307 J

A R

N

NA'CRB. (nacre, Fr. ndcchera, It.)
A sort of mother-of-pearl. The
fossil ink-bags of belemnites found
in the lias are surrounded by nacre.

NA'CREOTJS. Glistening; silvery; ir-
ridescent. Having the appearance
of mother-of-pearl. Many mem-
braneous shells exhibit a nacreous
appearance on their internal surface,
as the Haliotis, or sea-ear ; Anodon,
or fresh-water muscle, &c.

NA'CRITE. (from nacre.) A mineral
so called in consequence of its
pearly lustre. The Talcite of Kir-
wan. Nacrite occurs in reniform mas-
ses, composed of extremely minute
spangles, or glittering scales. Colour
pearly grey, with a tinge of red or
green. It fuses easily before the
blow-pipe. When rubbed between
the fingers it leaves a pearly gloss.
Unctuous to the touch. Its con-
stituents are, silex 56 '0, alumine
18-25, potash 8 -50, lime 3'10, iron
4-20, water 6-0.

N'AGLE-FLTJE. The name given to a
conglomerate of great thickness,
occuring in Switzerland.

NA'IAS. A genus of plants of the
order monandria, class dioscia, and
in the natural method ranking with
those of which the order is doubtful.
The male calyx is cylindrical and
bifid ; the corolla quadrifid ; there
is no filament, nor is there any
female calyx or corolla ; there is
one pistil ; the capsule is ovate and
unilocular. To this genus belong
the several species of zosterites,
found fossil in the cretaceous group.

NA'KED. (nackt, Germ.)

1. In botany, applied to flowers
having no calices ; to stems without
leaves; also to leaves when perfectly
smooth, and quite destitute of hairs.

2. In zoology, applied to molluscs,

when the body is not defended by a
calcareous shell.

NA'PHTHA. (vatfrda, Gr. naptha, Lat.
naphte, Fr.) A variety of bitumen,
thin, volatile, fluid, and inflamma-
ble; unctuous to the touch, and
constantly emitting a strong odour.
Colours yellowish- white and yel-
lowish-grey; transparent. Specific
gravity from 0- 70 to 0-85. It is
highly combustible, igniting even
on the approach of a lighted taper.
It burns with a white or bluish
flame, produces a dense smoke, and
yields no residuum. It is insoluble
in alcohol. When long exposed to
the air, it becomes yellow and then
brown; its consistence is increas-
ed, and it passes into petroleum.
Naphtha consists of carbon 82 '2,
hydrogen 14-8. Springs of it exist
in many countries, particularly in
the neighbourhood of volcanoes.
The finest varieties of naptha are
found on the shores of the Caspian.
The soil is sandy and marly, and
the surrounding minerals are cal-
careous. The naptha is constantly
rising in the state of an odorous
inflammable vapour. The inhabi-
tants of the town of Baku, a port on
the shores of the Caspian sea, are
supplied with no other fuel than
that obtained from the naphtha and
petroleum with which the neigh-
bouring country is highly impreg-
nated. Mr. Coxe estimates the
produce of the naphtha springs at
Rangoon, Pegu, at 92,781 tons per
annum. Naphtha is burnt in lamps
instead of oil.

NARC/ODES. The name assigned to a
genus of ichthyolites of the old red
sandstone.

NA'RWAL. | (narwhal, narwatt, Germ.

NA'KWHAX. ) the seauni«orn.) The

A S

[ 308 ]

N A U

Mbnodon monoceros of Linnaeus.
Placed by Cuvier in the family
Cetacea ordinaria, order Cetacea.
The tusk of this animal is some-
times ten feet long, and spirally
furrowed. Portions of the skull of
the narwahl have been found in
the Lewes levels, in Sussex.
NA'SSA. A genus of fossil univalve
shells separated from Buccinum by
the tooth-like projection which
terminates the columella ; ten fossil
species are recorded in the English
tertiary deposites, and two from the
green sand of Black Down, but the
genus of the latter is perhaps rather
doubtful.

NA'TATOEY, (from natator, Lat. a
swimmer.) Enabling to swim.
Certain organs possessed by many
animals are natatory organs. Seve-
ral of the cephalophods and ptero-
pods, and other molluscans, have
natatory appendages.
NA'TICA. A genus of nearly globose,
umbilicated, univalves, belonging
to the family Neritaeea. Aperture
entire and semicircular ; columella
transverse, without teeth, and
callous externally. These shells,
though strongly resembling Neri-
tse, may be distinguished from
those of that genus by their being
always umbilicated, and the colu-
mella never dentated. The recent
Natica is found in estuaries and
tidal rivers, in mud and sandy mud,
at depths varying to forty fathoms.
It is also found fossil.
NA'TEOLITE. The Natrolith of Wer-
ner; Natrolithe of Hau'y; con-
sidered by some mineralogists to be
a variety of prismatic zeolite.
Occurs in small, reniform, rounded,
or irregular masses, composed oi
very minute fibres ; the fibres are
divergent, or even radiate from a
centre, and are sometimes extreme-
ly minute and close. Colours
yellow, yellowish brown, and
brown, with striped-colour deline-
ations. Translucent at the edges

Sp. gr. 2*16, to 2-20. Before the
blow-pipe it fuses readily into a
white glass. In nitric acid it is
reduced, without any effervescence,
into a thick jelly. It derives its
name from containing soda. Its
constituents are silex 48 '20, alu-
mine 24-50, soda 16-10, oxide of
iron 1*75, water 9'0. It occurs
principally at Roegau, in Suabia,
imbedded in amygdaloid.
NA'TRON. (natron, Fr.) The Soude
carbonatee of Haiiy ; L'alkali min-
eral natif of Brochant ; the Natron
of Kir wan. A carbonate of soda
occurring massive and crystallised,
the principal supplies coming from
lakes in Egypt and Hungary. In
Egypt, the lakes which yield
natron abundantly are called the
Lakes of Natron. These are six in
number, to the westward of the
Nile, not far from Terrana, in a
valley, surrounded by limestone.
NA'TUEAL HISTOEY. This extensive
science has for its object the
enquiry into the being of natural
bodies, and their thorough investi-
gation in reference to their various
qualities, and the relative functions
of their component parts. Under-
stood in this extent, it presents us
with a distinct unique entirety,
which treats the natural body as
complete, but gradually perfected ;
and at the same time seeks to dis-
cover the means whereby it at-
tained its completion and perfection.
Natural history, therefore, is no
mere description of form, — no
description of nature, as it has been,
latterly, very incorrectly considered,
but a true and pragmatical history,
developed from its own funda-
mental principles. — Burmeister.
NAU'LAS. A genus of ichthyolites of

the old red sandstone.
NATJTILA'CEA. A family of Polytha-
lamous cephalopods, in the arrange-
ment of Lamarck. This family
comprises Discorbites, Nautilus,

N A U

Nummulites, Polystomella, Side-
rolites, and Verticialis.

NAUTI'LIDJB. A family of chambered
shells belonging to the order Tetra-
branchiata ; of this family the
nautilus is a genus.

NAU'TILITE. A fossil nautilus.

NATJ'TILFS. A genus of shells belong-
ing to the family Nautilida3. A
spiral, polythalamous, discoidal
univalve with smooth sides. The
turns contiguous, the outer side
covering the inner. The chambers
separated by transverse septa,
which are concave outwards, and
perforated by a tube passing through
the disk. Three or four recent
species are known. " It is a curious
fact," says Dean Buckland, "that
although the shells of the nautilus
have been familiar to naturalists,
from the days of Aristotle, and
abound in every collection, the only
authentic account of the animals
inhabiting them, is that by Rum-
phius, in his history of Amboyna."
At the present day the nautilus is
an inhabitant of tropical seas, but
its fossil remains are found in for-
mations of every age. The organ
of locomotion in the nautilus appears
to have been a foot, resembling that
of the snail. This organ is ex-
pansive, and surmounts the head.
The oral organs are much more
complicated and numerous than
those of the cuttle-fish, and are
furnished with no suckers. Its
tentacles are retractile within four
processes, each pierced by twelve
canals protruding an equal number
of these organs, so that, in all, there
are forty-eight. In fact, the whole
oral apparatus, except the mandi-
bles and the lip, is formed upon a
plan different from that of the
cuttle-fish, as likewise from that of
the carnivorous trachelipod mollus-
cans, and indicate very different
modes of entrapping and catching
their prey ; being deprived of suck-
ers, they seem destitute of any

309 "I N A U

powerful means of prehension and
detention. The eye, also, is reduced
to the simplest condition that the
organ of vision can assume, without
departing altogether from the type
of the higher classes, so that it
appears not far removed from that
of the proper molluscs. The nau-
tilus has only a single heart, the
branchial one being absent. The
nautilus resides in the capacious
cavity of its first, or external,
chamber ; and it is now well ascer-
tained that this animal is not a
piratical parasite, occupying the
shell of another animal, which it
has murdered, but that it lives, and
sails, in a skiff of its own building.
A siphuncle connects the body of
the nautilus with the air chambers,
passing through an aperture and
short projecting tube in each trans-
verse septum, till it terminates in
the smallest chamber at the inner
extremity of the shell. These in-
ternal chambers contain only air,
and have no commnnication with
the outer chamber but by one small
aperture in each septum through
which the siphuncle passes. No
water can by any possibility pass
into these chambers, between the
exterior of the siphuncle and the
siphonic apertures of the transverse
plates, because the entire circum-
ference of the mantle in which
the siphuncle originates, is firmly
attached to the shell by a horny
girdle, impenetrable by any fluid.
The number of chambers varies
greatly, according to the age of the
animal. Dr. Hook states that he
has found in some shells as many as
forty. The siphuncle, as appears from
Prof. Owen's statement, terminates
in a large sac surrounding the heart
of the animal; if we suppose this
sac to contain a pericardial fluid,
the place of which is alternately
changed from the pericardium to
the siphuncle, we shall find in these
organs an hydraulic apparatus for

A U

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E M

varying the specific gravity of the
shell; so that it sinks when the
pericardial fluid is forced into the
siphuncle, and becomes buoyant,
when the same fluid returns to the
pericardium. The substance of the
siphuncle is a thin and strong
membrane, surrounded by a coat of
muscular fibres, by which it could
contract or expand itself, in the
process of admitting or ejecting
any fluid to or from its interior.
When the arms and body are ex-
panded, the fluid remains in the
pericardium, and the siphuncle is
empty, and collapsed, and sur-
rounded by the portions of air
that are permanently confined
within each chamber ; in this state
the specific gravity of the body and
shell together is such as to cause
the animal to rise, and be sustained
floating at the surface. When, on
any alarm, the arms and body are
contracted, and withdrawn into the
shell, the retraction of these parts,
causing pressure on the pericar-
dium, forces its fluid contents into
the siphuncle, and as the quantity
of matter within the shell is thus
increased, without any increase of
magnitude, the specific gravity of
the entire animal is increased, and
it begins to sink. Rumphius states
that, at the bottom of the sea, the
nautilus creeps with his boat above
him.

Fossil remains of the nautilus
are found in strata from the moun-
tain limestone upwards. In some
of these the siphunculus is beauti-
fully preserved. But while, as a
genus, the nautilus occurs in for-
mations of every age, from the
transition series upwards, yet cer-
tain species appear limited to par-
ticular geological formations. The
eocene, miocene, and pliocene has
each its particular nautili. — Buck-
land) Kirby. Owen. Parkinson.
Sowerly.
NAUTILUS SY'FHO. The name given

to a very beautiful, camerated,
siphuncled fossil shell, found in the
tertiary strata at Dax, near Bour-
deaux. This fossil presents devia-
tions from the usual characters of
the nautilus, whereby it approxi-
mates to the ammonite.

IsTAu'TiLtrs zic ZAC. A fossil, camera-
ted, siphuncled shell, found in the
London clay. This and the naut-
ilus sypho appear to form connect-
ing links between the genera Naut-
ilus and Ammonite.

NECRO'PHAGOUS. (from veKpo?, dead,
and (pa^etv, to eat, Gr.) Animals
which devour dead substances.
The unclean animals, with respect
to their habits and food, were
divided into two classes ; namely,
zoophagous animals, or those which
attack and devour living animals;
and necrophagous animals, or those
which devour dead ones, or any
other putrescent substance.

NE'CROMITE. (from veKpo?, dead, Gr.)
A mineral occurring in small mas-
ses in limestone ; found near Balti-
more. When struck, it exhales a
fetid odour, resembling that of
putrid flesh ; from this quality it
obtained its name.

NE'CTARY. That part of a flower
which secretes and contains the
honey, (an almost universal fluid
in flowers) and is either a part of
the corolla, or an organ distinct
from it, and variously formed, as in
the monks'-hood, black hellebore,
&c. ; or it is a tubular elongation
of the calyx, or of a petal ; or, an
assemblage of glands.

NEE'DLE ORE. rlhe Nadelerz of Wer-
ner. Colour steel-gray. Amor-
phous, or in acicular hexaedral
prisms, which are occasionally in-
vested with a yellowish or greenish
crust. Fracture uneven and me-
tallic. Specific gravity 6*8. Con-
stituents, bismuth 43-6, lead 24-50,
copper 12-1 2, sulphur 11 '60, nickel
1-58, tellurium 1'32.

NEMATOIDE'A. The fourth order of

E E

[311 ]

NEE

the class Scolecidee; the thread-
worm.

NEE'DLE STONE. A variety of zeolite,
of a yellowish- white colour, found
in Iceland.

NEMATU'RA. A genus of shells be-
longing to the family Turbinacea.
Recent, and fossil.

NEMERTI'NA. The name assigned by
Dr. Mac Leay to an order of anne-
lida of the group apoda. He thus
describes them ; " animals aquatic,
without eyes or antennae. Body
not externally setigerous. Articu-
lation indistinct. The nemertinse
are white-blooded animals, like
some of the leeches."

NEMERTI'TES. A genus of nemertina,
thus named by Mr. Mac Leay.

NEOCO'MIAN. (from Neocomiensis, the
Roman name for Neufchatel.) The
name given by the French geolo-
gists to a formation synchronic
with the Wealden. Dr. Fitton
considers that the Neocomian strata
are but the equivalents of the
English greensand system.

N'EOLOGY. The introduction of a new
word or words, or of new names
into a language. Dr. Me. Culloch
has, notwithstanding his great dis-
like to neology, enriched our no-
menclature more than any other
British geologist, with new names.
— Dr. JBoase.

NEOZO'IC. A term proposed by Prof.
Forbes to include the Mesozoic and
Kainozoic epochs ; or to group the
whole of the great series of strati-
fied rocks, and divide the whole
lapse of past geologic time into
two great epochs only, namely
Palaeozoic and Neozoic.

NE'PHELINE. (from i/e^e'Xiy, a cloud,
Gr.) The Sommite of Jameson;
Nephelin of "Werner. A mineral
found only in the cavities of lava at
Mount Somma, from which circum-
stance it has been called Sommite.
Occurs generally in small, regular,
six-sided prisms, associated with
mica, hornblende, and idiocrase.

Specific gravity 3 '27. Colour grey-
ish-white, or greenish-grey. It is
translucent, and sometimes trans-
parent. Before the blow-pipe it
fuses, with difficulty, into a trans-
parent glass. Its constituents are
silex 46, alumine 49, lime 2, ox-
ide of iron 1.

NE'PHBITE. (from i/e0/a/T^?, ab i>e0/jo?,
a kidney, Gr.) A mineral, formerly
worn from an absurd notion that
diseases of the kidney were relieved
by so doing. It is a sub-species of
jade, possessing the hardness of
quartz, combined with a peculiar
tenacity which renders it difficult
either to break, cut, or polish. It
is unctuous to the touch ; fracture
splintery and dull ; translucent.
Colours green, grey, and white.
Sp. gr. from 2'9 to 3-1. Constitu-
ents, silex 53-80, lime 12-75, soda
10-80, potash 8-50, alumine 1'55,
oxide of iron 50, oxide of manga-
nese 2-0, water 2'30. Nephrite is
brought from India, China, and
Persia ; it is found also, in primary
rocks, in Germany and Egypt. It
is worked into handles for sabres,
knives, daggers, &c.

NEPTUNIAN THE'ORY. That theory
which attempted to prove that all the
formations have been precipitated
from water, or from a chaotic fluid.

NE'PTTJNISTS. The supporters of the
Neptunian theory ; they were op-
posed by the Yulcanists. Werner
taught that all the various for-
mations had been, each in succes-
sion, precipitated over the whole
earth from a common menstruum,
or elastic fluid. His disciples
supported his opinions to their full
extent, maintaining that even ob-
sidian was an aqueous precipitate.

NEREIDI'NA. Red-blooded, many-
legged worms, resembling elon-
gated centipedes. According to
Mr. Mac Leay, animals belonging
to the class Annelida, having a
distinct head, provided with either
eyes or antennee, or both. Mr. Mae

NEE

[ 312 ]

NEW

Leay observes, "these are the most
perfect in their structure of all
Annelida, as they possess numerous
organs, and have a distinct head.
Some of them, after the manner of
Serpulina, inhabit tubes, which
tubes are membranaceous, and
formed by a transudation from their
body; but in general, the Nerei-
dina are naked, and they are al-
ways agile animals freely moving
about in search of prey."

NEEEI'TES. A genus of Nereidina,
which, says Mr. MacLeay, " comes
very near to Savigny's genus Ly-
coris in its external appearance,
only the segments of the body are
here perhaps more slender and in
proportion longer than usual."
Sir E. Murchison has established
two species, namely, N. Cam-
brensis, and N. Sedgwickii, both
discovered in the older rocks of the
Silurian system.

NEEITA'CEA. A family of Tracheli-
pods, including the genera Natica,
Nerita, Neritina, Navicella, and
Janthina.

NEEITI'NA. A genus of fresh- water
univalves, belonging to the family
Neritacea. Shell thin, semiglobose,
obliquely oval, smooth, flattish in
front ; spire short ; aperture semi-
circular; outer lip thin; colum-
ella lip broad, flat, denticulated.
Differs from Nerita in the minute-
ness of the denticulation of the
columella.

NEEI'TA. A genus of marine univalves,
included in the family Neritacea.
The Nerita is a littoral shell, creep-
ing on rocks and sea-weeds. A
semi-globose univalve, depressed
beneath, and having no umbilicus ;
aperture entire and semicircular.
The aperture is generally large in
comparison with the shell, but it is
furnished with an operculum which
completely closes it.

NEEINEA, A genus of fossil turricated
univalve shells consisting of nu-
merous whorls ; the aperture has a

fold upon the columella, one on the
outer lip, and one on the inner lip
at the edge of the body whorl. A
longitudinal section of one of these
shells has a singular appearance
produced by the three folds; the
oolitic formations contain numerous
species. — Lycett.

NEEITO'PSIS. A genus of univalve
shells, separated from nerita by
the character of the columella lip,
which is smooth, flat, with a notch
in the centre of its inner edge.
The oolitic formations contain
several species.

NEUEO'PTEEA. (from vevpov, a nerve,
and Trrepov, a wing, Gr.) Nerve-
winged insects. Neuroptera, in
Cuvier's arrangement, constitutes
the eighth order of Insecta. The
Neuroptera have four membranous
wings, usually reticulated by nu-
merous nervures, but having no
sting, or ovipositor. The Neurop-
tera are mostly bold, rapacious, and
sanguinary ; perpetually chasing
and devouring other insects. The
libellula, or dragon-fly, is a familiar
example.

NETJEO'PTEEIS. A genus of fossil ter-
restrial plants found in the coal
measures.

EED SANDSTONE. (Called also
Eed Marl, Eed Eock, and Eed
Ground. The Gres Bigarres of the
French, and Bunter Sandstein of
the Germans.) A member of the
red sandstone group, lying between
the variegated marls and muschel-
kalk, and above the magnesian
limestone, or zechstein : sometimes
called variegated sandstone. The
marl and sandstone are often red,
but vary in their hue from chocolate
to salmon colour; they are not
unfrequently variegated, exhibiting
streaks of light blue or verdigris,
buff, or cream colour ; this forms so
prominent a character, that "Werner
denominated the formation "bunter
sandstein," variegated sandstone.
It is principally silicious and argil-

NEW

[313 ]

NEW

laceous, and is sometimes found to
contain mica, and masses of rock-
salt and gypsum. It affords a good
and handsome stone for building
purposes in some parts, when but
slightly coloured. It does not
abound in organic remains; among
its conchifera? may be enumerated
Plagiostoma, Avicula, Mytilus, Tri-
gonia, and Mya. Natica, Turritella,
and Buccinum may be included in
its genera of molluscs. By some,
the new red sandstone has been
divided into three series; the upper,
the middle, and the lower beds. Sir
R. Murchison proposes a four-fold
division of what he terms the new
red system, namely: 1. Saliferous
marls, &c. 2. Red sandstone and
quartzose conglomerate. 3. Cal-
careous conglomerate = magnesian
limestone. 4. Lower red sandstone.
Over a large part of England the
new red sandstone rests unconform-
ably upon the carboniferous group,
showing that the latter was dis-
turbed, dislocated, and partially
removed, before the former was
accumulated upon it ; there is,
however, reason to believe that in
other parts of the European area
deposits still continued quietly to
be thrown down upon undisturbed
parts of the carboniferous series, so
that no real line of separation can
be well established between them.
It is a very extensive deposit,
stretching, with but little interrup-
tion, from the northern bank of the
Tees, in Durham, to the southern
coast of Devonshire. It is almost
needless to observe, when we con-
template the red sandstone series
as a whole, and consider that it is
in great measure composed of matter
which must have been deposited
from water, where it was, for the
time, mechanically suspended, that
great variations should be expected
at the same geological levels ; here
clay or marl being found, there
sandstone or conglomerate, while,

occasionally, calcareous matter
should be dispersed among it, under
favourable circumstances, in suf-
ficient abundance to constitute nu-
merous beds of limestone.

When this deposit appears as a
sandstone, its characters differ
greatly in different places; it is
occasionally calcareous, and some-
times of a slaty texture. Above
all, this extensive deposit is re-
markable for containing masses of
gypsum, and the great rock-salt
formation of England occurs within
it, or is subordinate to it.
" Whether considered in its central
or in its lower member," says
Sir R. Murchison, " there is no
system of rocks, which occasionally
offers greater difficulties for deter-
mining its real laminse of deposit
than the new red sandstone. Besides
the joints or fissures, the diagonal
lines of false stratification are some-
times so prevalent, that is only by
tracing at wider intervals the true
laminee of deposit as marked by
herbage or moss, that we can
correctly ascertain the real dip of
the strata."

A very remarkable discovery was
made in 1828 of the foot-marks of
some unknown quadruped in strata
of new red sandstone, three miles
from Lochmaben in Dumfries- shire.
They were found forty-five feet un-
der the present surface ; the strata
are inclined thirty-seven degrees.

RED SANDSTONE GEOUP. This

includes all those deposits found
below the lias group, and above
the carboniferous group. It con-
tains the red or variegated marls
(marnes irisees, keuper), the mus-
chelkalk, the new red or variegated
sandstone (gres bigarre, bunter
sandstein), the zechstein or mag-
nesian limestone, and the red con-
glomerate (rothe todte liegende,
gres rouge). The whole is con-
sidered as a mass of conglomerates,
sandstones, and marls, generally of

• n

NEW

[314]

KIT

a red colour, but most frequently
variegated on the upper parts.

NEWEB PLIOCENE PEKTOD. The term
"Newer Pliocene" has been sup-
planted by that of Pleistocene, but
as many readers may find in works
on geology, written only a few years
since, the term " Newer Pliocene,"
I have retained it in this edition.
Lyell refers the European tertiary
strata to four successive periods,
each characterized by containing a
very different proportion of fossil
shells of recent species. These
four periods he termed Newer Plio-
cene, Older Pliocene, Miocene and
Eocene ; the etymology of these
terms will be fully explained under
the several words. The Newer
Pliocene period is the latest of the
four periods, and immediately pre-
cedes the recent era. Nevertheless,
the antiquity of some Newer Plio-
cene strata, as contrasted with our
most remote historical eras, must
be very great, embracing perhaps
myriads of years. Out of 226
fossil species brought from the
Sicilian beds, M. Deshayes found
that no fewer than 216 were of
species still living.

NI'CZEL. (nickel, Germ.) A metal
of considerable hardness, nearly
equal to that of iron, of a colour
intermediate between silver and
platina. When polished, it has a
high lustre. Specific gravity 8*93.
It is both ductile and malleable,
and may be hammered into very
thin plates. It is difficult to be
purified. In common with iron,
it is magnetic, capable of acquiring
polarity, and may be formed into
permanent magnetic needles ; this
property is destroyed by an alloy
with arsenic. Nickel unites in
alloys with gold, copper, tin, and
arsenic, which metal it renders
brittle. With silver and iron its
alloys are ductile.

Nickel was discovered as a dis-
tinct metal by Cronstadt, in 1751.

Its solution in nitric acid is nearly
grass green. Nickel is found in all
meteoric stones.

NI'GETNE. (from niger, Lat. black.)
A variety of ferruginous oxide of
titanium, occurring in grains, or
rolled pieces. Colour black, or
brownish black. It consists of
titanium 84, oxide of iron 14,
oxide of manganese 2.

NIO'BIUM. One of the sixty simple
or elementary bodies, its symbol
being N B.

NIPADI'TES. The name given by Mr.
Bowerbank to a group of fossil
fruits of the London clay. Brong-
niart had named them Pandano-
carpum, but Mr. Bowerbank ob-
serves " the resemblance existing
between the whole of the species of
Nipadites, both as regards their
external form and their internal
structure, with those of Nipa, is so
close as to leave scarcely a doubt
of their being members of the same
genus. I have therefore thought
it advisable to reject M. Adolphe
Brongniart's name of Pandano-
carpum, and to apply that of
Nipadites, as more expressive of
their true relation to their recent
analogue." These fossil fruits are
found in great abundance in the
Isle of Sheppey, and are known,
by the women and children who
collect them, by the name of figs.
Many species have been distin-
guished.

NI'TRATE. A compound of nitric acid
with a salifiable base.

NI'TRE. (vlvpov, Gr.) Nitrate of
potash ; saltpetre. The potasse
nitratee of Haiiy ; natiirlicher sal-
peter of Werner. Nitre, or nitrate
of potash, is found native in all
countries, where there are circum-
stances favourable to its production.
It frequently effloresces on the soil ;
but never exists at a greater depth
than that of a few yards beneath
the surface. It occurs, naturally,
either in masses, or in thin ir-

KIT

[315 J

NIT

regular crystals ; it is white, semi-
transparent, and brittle ; salt and
cold in taste. When thrown on
hot coals, it burns with a sparkling
bright light, and with a crackling
noise. It crystallizes in six-sided
prisms, terminated by a dihedral
summit, and retains no water of
crystallization. The crystals are
permanent, and soluble in seven
parts of water at 60°, and in less
than their own weight at 212°.
The principal supply of nitre is
from India. One of the most re-
markable localities of nitre in
Europe, is in the Pula, or cavity of
Molfetta, in the kingdom of Naples.
This cavity, which is about one
hundred feet deep, contains several
grottoes or caverns, in the interior
of which is found nitre in crusts,
attached to compact limestone.
"When these crusts are removed,
others appear in about a month.
The various sources of native nitre
not being sufficient to supply the
great demand there exists for it, it
is manufactured wholesale, in the
following manner. Rubbish, con-
sisting of lime, mortar, plaster, and
earth, is mixed up in heaps, under
sheds, with decaying vegetables
and refuse matter, and left to rot;
the masses being occasionally
moistened with animal fluids, as
urine, blood, &c. The nitrogen,
disengaged from the corrupting
mass, unites with the oxygen of
the atmosphere, and forms nitric
acid ; this, combining with the
potash furnished by the vegetable
substances, produces an impure
nitre. The salt is collected, and
afterwards washed and purified.
NI'TROGEN. (from vhpov, nitre, and
yewdu), to produce, Gr.) Called
also azote. Nitrogen was disco-
vered in 1772 by Prof. Rutherford,
of Edinburgh : it may be obtained
by several processes, the object of
most of which is to take away
the oxygen gas from atmospheric

air, of which nitrogen constitutes
above four-fifths, or eighty per cent.,
the rest being principally oxygen.
In its pure state, nitrogen is re-
markable for its negative qualities ;
that is to say, for the difficulty
with which it enters into combi-
nation with other matters. Thus,
it is neither combustible, nor a
supporter of combustion ; it is
neither acid, nor alkaline; pos-
sesses neither taste, colour, nor
smell ; nor does it directly combine
with any known substance. Yet
when made by peculiar manage-
ment to unite with oxygen, hy-
drogen, or carbon, nitrogen forms
some of the most energetic com-
pounds we possess; thus, mixed
with oxygen, it forms atmospheric
air ; united with oxygen, it forms
aquafortis, the most corrosive of
liquids ; united with hydrogen, it
forms the volatile alkali, or am-
monia, likewise an energetic com-
pound, but of an opposite nature ;
while united with carbon and
hydrogen, it forms prussic acid, the
most virulent poison in existence.

The absorption of nitrogen during
respiration, was one of the results
Dr. Priestley deduced from his
experiments ; and this fact, though
often doubted, appears, on the
whole, to be tolerably well as-
certained by the inquiries of
Davy, Pfaff, and Henderson.
With regard to the respiration
of cold blooded animals, it
has been satifactorily established
by the researches of Spallanzani,
and more especially by those of
Humboldt and Proven9al, on fishes,
that nitrogen is actually absorbed.
A confirmation of this result has
been obtained by Macaire and
Marcet, who have found that the
blood contains a larger proportion
of nitrogen than the chyle, from
which it is formed.

Nitrogen has been recently found,
by Dr. Daubeny, to be contained

N 0 A

[316 ]

N 0 M

Yery generally in the waters of
mineral springs. The king's bath,
at Bath, evolves 96*5 per cent, of
nitrogen, 3'5 oxygen, and some
carbojiic acid. The hot-well at
Bristol evolves 92 per cent, nitro-
gen, and 8 oxygen. The springs
at Buxton, Bakewell, and Stony
Middleton, Derbyshire, evolve ni-
trogen only. Those of the Spas
in Germany, yield various propor-
tions, as do the other thermal
springs in other parts of the globe.
Its specific gravity is 0*9722.
The combining power of nitrogen
is variously estimated, some chem-
ists making it 14*15, while others
consider it to be only half of that
number. Its symbol is N.

NOA'CHIAN. Pertaining to the great
deluge related by Moses, from
which Noah and his family were
saved, and thus called after Noah.
Cuvier says " that if there be any
one fact thoroughly established by
geological investigations, it is the
certainty of the low antiquity of
the human race, and present state
of the surface of the earth, and the
circumstance of its having been
recently overwhelmed by the waters
of a transient deluge."

NODE, (nodus, a knot, Lat. nodus,
Fr. nado, It.) 1. A hard knot or
swelling, a bump, or rising.
2. In astronomy, the nodes of a
satellite's orbit are the points in
which it intersects the plane of the
orbit of a planet. The ascending
node is the point through which
the body passes in rising above the
plane of the ecliptic, and the de-
scending node is the point through
which the body passes in sinking
below the plane of the ecliptic.

NOCTI'VAGANT. j (from nox, the night,

NocTi'vAGous. j and vagor, to wan-
der, Lat.) A name given to such
animals as wander, in search of
prey, during the night.

NODOSA'BIA. A genus of orthocerata,

found only fossil. They are poly-
thalamous univalves.

NO'DTTLAR. In the form of a nodule
or small lump ; having irregularly
globular elevations.

NO'DULAK IKON ORE. A variety of
argillaceous oxide of iron ; occur-
ring in masses, varying from the
size of a walnut to that of a man's
head. Their form is spherical,
oval, or nearly reniform, or some-
times like a parallelepiped with
rounded edges and angles. They
have a rough surface, and are essen-
tially composed of concentric layers.
These nodules often contain, at the
centre, a kernel or nucleus, which
is sometimes moveable, and always
differing from the exterior in colour,
density, and fracture. The texture
of the exterior is compact and solid ;
but the density gradually dimin-
ishes to the centre, which has an
earthy texture. Specific gravity,
about 2'57. Its constituents are
oxide of iron 77'0, silex 6-0, oxide
of manganese 1-0, alumine 0'5,
water 13*5. These nodules have
also been called (Etites and Eagle-
stones, from an opinion that they
were found in eagles' nests, where,
it was supposed, they prevented the
eggs from becoming rotten.

NO'DULE. (from nodulus, a little knot,
Lat.) A rounded, irregular-shaped
mineral mass. Ironstone forms
regular layers of round nodules,
sometimes as much as a foot or
eighteen inches in diameter. These
nodules, when broken open, are
often found to be traversed by
cracks in all directions, more or
less filled up with crystalline spar,
together with crystals of galena,
blende, iron pyrites, and other
minerals. — Jukes.

NO'GBOBS. A fossil resembling a
belemnite.

NOMENCLATURE, (nomenclatures, Lat.
nomenclature, Fr. collection des mots
qui sont propres aux differentes par-
ties d'une science ou d'un art.) The

N 0 M

names of things in any art or science,
or the whole vocabulary of tech-
nical terms which are appropriated
to any particular branch of art or
science.

The imposition of a name on any
subject of contemplation is an epoch
in its history of great importance.
It not only enables us readily to
refer to it in conversation or wri-
ting, without circumlocution, but,
what is of more consequence, it
gives it a recognized existence in
our own minds, as a matter for
separate and peculiar consideration.
How important a good system of
nomenclature is, may at once be
seen, by considering the immense
number of species presented by
almost every branch of science of
any extent, which absolutely re-
quire to be distinguished by names.
Thus, the botanist is conversant
with from 80,000 to 100,000
species of plants ; the entomologist
with, perhaps, as many, of insects.
And the same as regards chemistry,
astronomy, &c.

Nomenclature, then, is, in itself,
an important part of science, as it
prevents our being lost in a wilder-
ness of particulars, and involved in
inextricable confusion. Happily,
in those great branches of science,
where the objects of classification
are more numerous, and the neces-
sity for a clear and convenient
nomenclature most pressing, no
very great difficulty in its estab-
lishment is felt. The facility with
which the chemist, the botanist, or
the entomologist, refers by name
to any individual object in his
scinece, shows what may be effected
in this way when characters are
themselves distinct.

Nomenclature, in a systematic
point of view, is as much, perhaps
more, a consequence than a cause
of extended knowledge. Any one
may give an arbitrary name to a
thing, merely to be able to talk of

[ 317 ] N 0 M

it ; but to give a name which shall
at once refer it to a place in a
system, we must know its proper-
ties ; and we must have a system,
large enough, and regular enough,
to receive it in a place which
belongs to it and to no other.

There is no science in which the
evils resulting from a rage for
nomenclature have been felt to such
an extent as in mineralogy. The
nomenclature of most minerals is
at present so encumbered with
synonyma, that it has become ex-
tremely perplexing to the student.
This may be illustrated by the
example of Epidote. This mineral,
which is called epidote by Haiiy, is
named pistazit by "Werner, thallite
by Lemetherie, alcanticone by Dan-
drada, delphinite by Saussure, glassy
actinolite by Kirwan, arendalit by
Karsten, glassiger strahlstein by
Emmerling, la rayonnante vitreuse
by Brochant, prismatoidischer augit-
spath by Mohs, &c., &c.

In all subjects where compre-
hensive heads of classification do
not prominently offer themselves,
all nomenclature must be a balance
of difficulties, and a good, short,
unmeaning name, which has once
obtained a footing in usage, is pre-
ferable to almost any other ; Fab-
ricius maintained " optima nomina,
quce omnino nil significant."
When the composition is unknown,
those names, which are altogether
unmeaning in regard to any pro-
perty of the thing, are, perhaps,
the least objectionable ; at all
events, they cannot lead to error.

Linnaeus was the first to intro-
duce systematic names into natural
history. By the introduction of
these scientific, fixed, and univers-
ally valid names, Linnaeus has
undoubtedly acquired his greatest
merit in science, and if every thing
else which he has done should be
forgotten, this, which ie wholly his
work,, will secure his name from

0

forgetfulness. — SerscheL
land. Burmeister. Lyell.

NON'ETJMINANTIA, The order artio-
dactyla, or those animals possessing
an even number of toes, is divided
into two families, nonruminantia
and ruminantia ; the hippopotamus,
pig, &c., are examples.

NO'RKA. The name given by Cron-
stadt to an aggregate of quartz,
mica, and garnet. This aggregate
is included by Kir wan in the gran-
atines.

NO'RFOLK CRAG. An English tertiary
formation belonging to the older
pliocene. It is observed to rest on
the chalk and on the London clay.
It consists of irregular beds of fer-
ruginous sand clay, mixed with
marine shells. According to an
account of Mr. S. Woodward, if a
line be drawn from Cromer, on the
northern coast of Norfolk, to Way-
burn, about six miles west, and
from thence extending in a southerly
direction towards Norwich, about
18 miles, it will comprise all the
regular beds of Norfolk crag.

NO'RITE. The name assigned by
Esmarck to a rock not yet deter-
mined; some of its characters
appear to belong to diorite, and
some to gabbro.

NOTHO'CERAS. M. Barrande has lately
established a new genus of Cepha-
lopod under this designation. It
is intermediate between Nautilus
and Goniatite, and is of the Upper
Silurian age.

NOTHO'SAURTJS. A reptile of lacertian
or lizard-like character, of the new
red sandstone era.

NOVA'CULITE. (from novacula, a razor,
Lat.) The Wetz schiefer of Wer-
ner; argile schisteuse novaculaire
of Hauy. Honestone. See Hone.

NI/CLEOLI CES. A genus of radiaria,
twelve species of which have been
determined as occurring in the
chalk formation, and six species as
occurring in the oolite.

NU'CULA. A genus of marine bivalve

[ 318]

IS" U M

shells belonging to the family
Arcacea. An inequilateral, equi-
valved, transverse, subtrigonal bi-
valve ; covered with an epidermis.
The hinge linear, bent at an angle
formed by numerous, alternately
inserted teeth ; muscular impres-
sions, two, simple; beaks approxi-
mating, and turned backwards.
The recent species of this genus
are found in estuaries, and in the
ocean, at depths varying to sixty
fathoms, in mud and sand. Several
fossil species are described.

NU'DIBRANCHIATA. The second order
of the class Gasteropoda. The nu-
dibranchiata have no shell what-
ever; neither are they furnished
with any pulmonary cavity, their
branchiaa being exposed on some
part of their back, from which cir-
cumstance they have obtained their
name. The triton, doris, &c., are
examples.

NT^MMULITE. (from nummuSf money,
Lat. and \i0os, a stone, Gr.)
The nummulites compose a fossil
extinct genus of multilocular ce-
phalopods, presenting, externally,
a lenticular figure, without any
apparent opening, and, internally,
a spiral cavity, divided by septa
into numerous chambers ; they do
not possess a siphuncle, but their
chambers communicate by means
of small foramina with each other.
They have obtained their name
from their supposed resemblance to
pieces of money. It is of stone
composed of Nummulites that the
pyramids of Egypt are constructed.
Nummulites have been named He-
licites, from their spiral structure ;
Phacites, from their resemblance
to a lentil ; and Salicites, from the
supposed resemblance of their sec-
tions to the leaf of the willow.
Pliny is supposed to refer to them
under the name of Daphnias when
he mentions that Zoroaster em-
ployed these substances for the cure
of epilepsy. They have been also

U M

[319]

0 B L

termed Lentes lapidese, Lapides
cumini, circulares, numismales, &c.

Nummulites vary in size from
less than an eighth of an inch, or
even microscopic minuteness, to an
inch and a half in diameter. Their
surface is, in some, nearly smooth,
in others rough and scabrous, with
numerous small projecting knobs,
or undulating lines. Their colour
varies from nearly white to brown
and red, and sometimes nearly blue.
The number of spiral turns seems
to depend on the age and size of
the animal; in those of a quarter
of an inch in diameter, being three
or four, while in those of the largest
size the number of whorls is fre-
quently upwards of twenty.

Nummulites occupy an important
place in the history of fossil shells,
on account of the prodigious extent
to which they are accumulated in
the later members of the secondary,
and in many of the tertiary strata.
They are often piled on each other
nearly in as close contact as the
grains in a heap of corn. Entire
calcareous hills are, in some in-
stances, composed of fossil nummu-
lites.

NTTMMTJLI'TIC. Containing nummu-
lites; composed of nummulites.
The nummulitic limestone of the
Alps, a formation which extends
through all the countries surround-
ing the Mediterranean, and thence
through Lower Asia into India, and
which is many thousands of feet in
some places, has been shown by
Sir B. Murchison to be clearly

referrible to the eocene period.—
Jukes.

NUTA'TION. (from nutatio, a nodding,
Lat. nutation, Fr.) A tremulous or
vibratory motion of the earth's axis,
by which its inclination to the plane
of the ecliptic is continually vary-
ing, being, in its annual revolution,
twice inclined to the ecliptic, and
as often returning to its former
position. Both the celestial lati-
tudes and longitudes are altered to
a small degree by nutation. In
consequence of this real motion
in the earth's axis, the pole-star,
forming part of the constellation of
the Little Bear, which was formerly
12° from the celestial pole, is now
within 1° 24' of it, and will con-
tinue to approach it till it is within
J°, after which it will retreat from
the pole for ages ; and 12,934 years
hence, the star a Lyrae will come
within 5° of the celestial pole, and
become the polar star of the north-
ern hemisphere.

NUT-GALL. An excrescence which
grows on some species of oaks.
These excrescences are produced
by the Cynip quercus folii, of Lin-
naeus, a small insect which deposits
its egg in the tender shoots of the
quercus infectoria, a species of oak
abundant in Asia Minor. When
the maggot is hatched, it produces
a morbid excrescence of the sur-
rounding parts, and it ultimately
eats its way out of the nidus thus
formed, and makes its escape. The
best galls are imported from Smyrna
and Aleppo.

0

OB'CONTCAL. Of the shape of a re-
versed cone.

OBCO'BDATE. In botany, an epithet
for an inversely heart-shaped leaf,
petal, or legume.

O'BLATE. (ollatus, Lat.) Flattened
or depressed at the poles ; generally
applied to spherical bodies, flattened
at the poles; of the shape of an
orange.

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L 320 ]

0 C E

OBEA'TE SPHE'KOID. A spheroid flat-
tened at the poles is called an oblate
spheroid : such is the form of the
earth and planets. When, on the
contrary, a spheroid is drawn out
at the poles instead of being flat-
tened, it is called a prolate spheroid.

OBLI'QUE. (olliquus, Lat. oblique, Fr.
olll'icOj It.) Not direct; not per-
pendicular ; not parallel.

In botany, applied to the position
of leaves, and implies that one part
of the leaf is horizontal and the other
vertical.

In conchology, applied to the
whorls of spiral univalves which
commonly are in an oblique direc-
tion in reference to the axis of the
shell. The term is also applied to
bivalves when they slant off from
the umbones.

OBLONG, (ollongus, Lat. oblong, Fr.)
Having greater length than breadth;
longer than broad.

In botany, applied to leaves
several times longer than broad.
The term is chiefly used to dis-
criminate a leaf whose form does
not accurately come under the de-
nominations oval, linear, or round.

O'BLONG O'VATE. Oblong egg-shaped ;
between oblong and egg-shaped.

OBO'VATE. In botany, applied to leaves
having the form of an egg, with the
broad end forming the base, and the
pointed the apex of the leaf.

OBSI'DIAN. The Obsidienne of Brong-
niart; Lave vif reuse obsidienne of
Haiiy. Vitreous lava, a volcanic
production, of a dark green colour
approaching to black. An analysis
of obsidian from Mount Hecla, by
Yauquelin, gives the constituents
as follows, silica 78, alumina 10,
potash 6, lime 1, soda 1*6, oxides
of iron and manganese 1 .

Obsidian has been divided into
two kinds, the vitreous and pearly ;
these may be distinguished by their
fracture, which is either vitreous
or pearly. Professor Jameson di-
vides obsidian into two subspecies,

namely, transparent obsidian and
translucent obsidian.

Vitreous obsidian bears a strong
resemblance to the glass of wine-
bottles. Its fracture is conchoidal,
showing frequently large cavities.
Lustre vitreous. Specific gravity
from 2-34 to 2-90. It generally
occurs in large amorphous masses,
when it appears almost black ; it is
sometimes found in rounded grains.
Pearlstone, the Obsidienne perlee
of Brongniart ; this variety has a
granular structure, and is traversed
by fissures in all directions. It is
consequently very brittle. Its frac-
ture is uneven or granular, and, as
before mentioned, pearly. When
moistened by the breath it fre-
quently returns an argillaceous
odour. It occurs amorphous only.
Before the blow-pipe both varie-
ties intumesce, but the vitreous
alone fuses into a globule. Obsi-
dian bears indisputable characters
of having once been in a state of
fusion.

OBTTJ'SE. (obtusus, Lat. obtus, Fr.)
An angle which is more than ninety
degrees, or that of a right angle.

O'BVOLTJTE. In botany, applied to
leaves, when their margins alter-
nately embrace the straight margin
of the opposite leaf.

OCCI'PITAL. (from occiput, Lat.)
Pertaining to the back part of the
head.

O'CCIPTJT. (occiput, Lat.) The back
part of the head : the fore part is
called sinciput.

O'CEAN. (wKeavos, Gr. oceanus, Lat.
octan, Fr. ocedno, It.) That vast
body of water which covers more
than three-fifths of the earth's
surface. The average depth of the
ocean has been very variously esti-
mated. Laplace considered, in
order to account for the height of
the tides according to the laws of
gravitation, the depth to average
ten miles ; others rate it at five
miles. The present cannot be con-

0 C E

LS21 ]

0 C T

sidered as having always been the
bed of the ocean ; on the contrary,
what are now the most elevated
portions of the earth's crust were
once submerged, and over them the
ocean for ages rolled its majestic
waves. This is not an invention
of modern geologists, Ovid declares
the same : —

Vidi factas ex sequore terras ;
Et procul a pelago concha) jacuere marines ;
Et vetus inventa est in montibus anchora summis ;
Quodque fuit campus, vallem decursus aquarum
Fecit; et eluvie mons est deductus in a>quor :
Eque paludosa siccis humus aret arenis ;
Qusequesitimtulerarit.stagnatapaludibushument.
Metamorph. lib. xv.

OCEA'NIC DE'LTA. A delta formed at
the mouth of rivers where they
enter the ocean, as distinguished
from either lacustrine or mediter-
ranean deltas.

OCELLA'RIA. A genus of fossils, thus
described by Mr. Parkinson : " a
lapideous polypifer, expanded in a
membranous form ; variously con-
voluted and rather infundibuliform,
with an arenaceous surface, porous
on both sides; pores cylindrical,
in quincunx order, with a solid
axis in a raised centre."

O'CELLATED. (pcellatus, Lat.) In con-
chology, applied to shells, when
marked with little eye-like spots.

OCHRA'CEOUS. Of a brown yellow
colour, resembling ochre. Alter-
nating with an orchraceous iron-
stone.

O'CHRE. (w'xipa) Gr. ocJira, Lat. ocre,
Fr.) Bed iron ore ; it yields good
malleable iron. Colours red, yel-
low, and brown. It occurs in dull
earthy masses, nearly or quite
friable, which soil the fingers. Its
constituents are oxide of iron 83,
silex 4, water 12.

OCRY'NIAN. The Ocrynian formation
is not only distinguished by con-
taining shorl, but also by a great
excess of felspar, which forms the
principal constituent in nearly all
its rocks.

OCTAC'DEAL. } Having eight sides

OCTJLHE'DRAL. j all equal.

OCTACDRITE. | Octaedral oxide of ti-
OCTOCDRITE. j tanium ; the Titane
anatase of Brongniart ; Octaedrit
of Werner ; Octaedrite of Jameson ;
the Oisanite of Lameth. A pure
oxide of titanium, crystallized in
acute, elongated octaedrons, con-
sisting of two pyramids, whose
faces are isosceles triangles, and
whose bases are squares. Colours
blue, blackish-blue and brown.
Lustre splendent and adamantine
Fracture foliated ; easily broken.
It scratches glass. Specific gravity
3 -8. Before the blow-pipe it is
infusible by itself, but with borax
it fuses into a glass. It occurs in
veins in Dauphiny, Norway, Spain,
and Brazil.

OcTAe'DRON. } (o/cTaefy>os, from o/rra>,

OCTAHEDRON, j eight, and edpa, a
side, Gr. octa&dre, Fr.) The solid
angles of an octaedron are formed
by four equal and equilateral plane
triangles ; consequently it is formed
by two equal spare pyramids joined
together at their bases, the sides
whereof are equilateral triangles.
The octahedron (unlike some forms
which are not susceptible of varia-
tion, as the die or cube, a solid
invariably bounded by six square
surfaces or planes) is susceptible of
variation ; it is sometimes flat and
low, and, at others, acute and high.

O'CTOPUS. (from OKTW, eight, and
TTOV^, a foot, Gr.) A genus of
sepiae. The octopus was the animal
denominated polypus by Aristotle.
It has eight arms, all of equal
length, and contains in its interior
two very small rudimental shells,
formed by the inner surface of the
mantle.

O'CTODENTATE. (from octo, eight, and
dentatus, toothed, Lat.) Having
eight teeth, and no more.

O'CTOFID. (from octo, eight, andjindo,
to cleave, Lat.) Eight-cleft. In
botany, an epithet for a calyx di-
vided into eight segments.

OCTOLO'CULAE. (from octo, eight, and

0 C T

[ 322

OLD

kcuhist a cell or pocket, Lat.) Eight-
celled.

OCTONO'CULAB. (from octo, eight, and
oculus, an eye, Lat.) Having eight
eyes.

OCTOPE'TALOUS. (from OKTW, eight,
and TreTrtXoi/, a petal, Gr.) Having
eight petals or flower-leaves.
OCTOSPE'BMOFS. (from OKT-W, eight,
and aTrep/Lui, seed, Gr.) Eight-
, seeded ; having eight seeds.
ODONTACA'NTHUS. A genus of ichthy-
olites of the old red sandstone for-
mation, previously known as C ten-
op tychius, but for which Odonta-
canthus has been substituted. Two
species have been described by
Agassiz.

(Eso'pHAGUS. (cesophage, Fr.) The
gullet, or passage leading from the
mouth to the stomach, through
which the food passes. In the
structure of the oesophagus, we
may trace an adaptation to the
particular kind of food taken in by
the animal. When it is swallowed
entire, or but little changed, the
oesophagus is a very wide canal,
capable of being greatly dilated.
Serpents, which swallow animals
of greater circumference than them-
selves, have an oesophagus admit-
ting of great dilatation ; the food
in such cases remaining a long time
in the canal, before it reaches the
stomach. Grazing animals, who
carry their heads close to the ground
while feeding, have the oesophagus
strengthened by thick muscular
coats, whereby the food is propelled
towards the stomach, the direction
being contrary to that of gravity.
OGY'GIA. The name given by Brong-
niart to a genus of trilobites; he
thus defines the generic characters :
"Corps tres deprime*, en ellipse
allonge*e, non contractile en sphere.
Bouclier horde* ; un sillon peu pro-
fond, longitudinal, partant de son
extre'mite' ante*rieure. Pointd'autres
tubercules que les oculiformes.
Lobes longitudinaux peu saillans.

Huit articulations a 1'abdomen."
In establishing this genus, M.
Brongniart observes that although
its appearance is very different
from that of most other genera of
the family of trilobites, yet it is
not always easily separated from
them.

OGY'GES. The name given by Guet-
tard to a species of trilobite, from
its being found among the most
ancient rock formations, containing
vestiges of organic life.
O'KENITE. A bi-silicate of lime, with

two equivalents of water.
OLD EED SANDSTONE. (The Gres rouge
intermediare of the French; the
Jiingeres Grauwackengebirge, and
Alter rother sandstein of the Ger-
man geologists.) The lowest mem-
ber of the carboniferous group,
extensively developed in the coun-
ties of Shropshire and Hereford-
shire, in England ; Brecknockshire,
in Wales; and Dumfriesshire and
Forfarshire, in Scotland. The old
red sandstone strata lie between
the carboniferous series and the
silurian rocks, or grauwacke group.
It consists of many varieties and
alternations of silicious sandstones
and conglomerates of various colors,
red predominating. The old red
sandstone of some countries gradu-
ates into grauwacke, and it is the
opinion of most continental geolo-
gists that it should be considered as
forming the upper portion of the
grauwacke series. The old red
sandstone is a course-grained, mi-
caceous sandstone, evidently of
mechanical origin, constituted ap-
parently of abraded quartz, felspar
and mica, and containing fragments
of quartz, clay-slate, flinty-slate,
&c. ; sometimes passing into the
state of a quartzose conglomerate,
sometimes possessing a structure
coarsely schistose, and sometimes,
particularly towards its lower re-
gions, becoming finely schistose,
and passing into a fine-grained

OLD

[ 823 ]

0 L I

micaceous sandstone slate. In
some situations the old red sand-
stone attains a thickness of 2000
feet and upwards.

" It was a prevalent belief among
geologists," says Sir E,. Murchison,
"that few or no animal remains
existed in the old red sandstone of
England. I first undeceived myself
on this point by observing shells in
the lower group, or tilestones, in
Caermarthenshire. I afterwards
discovered similar fossils in the
great outlier of Clun forest. The
old red system may now fairly be
said to be characterized throughout
by ichthyolites peculiar to it. The
rocks known to English geologists
under the name of the old red
sandstone, consist of various strata
of conglomerate, sandstone, marl,
limestone, and tilestone, the young-
est beds of which dip conformably
beneath the carboniferous deposits,
whilst the oldest repose upon and
pass into certain grey-coloured rocks.
These last form the upper part of
the Silurian system."
OLD EED SYSTEM. Sir R. Murchison
has applied this term to what has
heretofore been known as the old
red sandstone. ' ' Being convinced, ' '
he says, "that the old red sandstone
is of greater magnitude than any of
the overlying groups, I venture for
the first time, in the annals of
British geology, to apply to it the
term system, in order to convey a
just conception of its importance in
the natural succession of rocks, and
also to show, that as the carboni-
ferous system, in which previous
writers have merged it (but from
which it is completely distinguish-
able, both by lithological characters
and zoological contents,) is sur-
mounted by one red group ; so it is
underlaid by another, this lower
group being infinitely thicker than
the upper." Sir R. Murchison
proposes to divide the old red system
into — 1, Quartzose conglomerate

and sandstone. 2. Cornstone and
marl. 3. Tilestone. He considers
the united thickness of the old red
system, at a moderate calculation,
to amount to nine or ten thousand
feet.

" It will be found," says Hugh
Miller, "that this hitherto neg-
lected system yields in import-
ance to none of the others, whether
we take into account its amazing
depth, the great extent to which it
is developed both at home and
abroad, the interesting links which
it furnishes in the zoological scale,
or the vast period of time which it
represents. There are localities in
which the depth of the old red
sandstone fully equals the elevation
of Mount Etna over the level of the
sea, and in which it contains three
distinct groups of organic remains,
the one rising in beautiful progres-
sion over the other." See Tilestone.

OLDEE PLIOCENE. Sir C. Lyell has
sub- divided the tertiary epoch into
four periods; namely, the newer
pliocene or pleistocene, the older
pliocene, the miocene, and the
eocene. The term pliocene he
derived from the two Greek words
ir\eiicv, more, and, KCUVO?, recent.
The older pliocene formations lie
between the miocene and the newer
pliocene or pleistocene. Of fossil
shells examined by M. Deshayes,
the older pliocene contained from
thirty- five to fifty per cent, of recent
fossils.

OLE'CRANOBT. (o\eicpavov, Gr. from
u>\wrjt the ulna, and Kapyvov, the
head.) A process of one of the
bones of the fore arm, the ulna,
forming part of the elbow joint.

OLE'FIANT GAS. (from oleum, oil, and
fio, to become, Lat.) A gas devoid
of colour and taste, deriving its
name from the property it possesses
of forming an oil-like liquid with
chlorine.

O'LIQOCLASE. Soda Spodumene. A
feldspathic mineral, whose const!-

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[324]

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tuents are silica 63-37, alumina
25-86, soda 11'77.

O'UVA. (olwa, an olive, Lat.) So
named from the oblong and ellip-
tical shape of the shell. A marine
suhcylindrical univalve; aperture
narrow, long, and emarginated
opposite to the spire, which is
short ; the plicae of the columella
are numerous, and resemble striae ;
whorls sulciform. The shells of
this genus are very beautiful, and
display a great variety of rich
markings and splendid colours.
Recent olivae are found at depths
varying to twelve fathoms, in mud,
sandy mud, coarse sand, &c. They
are also caught by fishing lines.
Fossil olivae are found in the cal-
caire grossier, and London clay.
Several species have been described.

OLI'VENITE. An ore of copper of an
olive-green colour. It consists of
oxide of copper 63 '0, phosphoric
acid 28-6, water 8-4.

O'LIVINE. The prismatischer chryso-
lithe of Mohs; peridot of Haiiy;
olivin of Werner. A mineral,
generally of an olive-green colour,
from which circumstance it obtains
its name : it is sometimes of an
asparagus green, or yellowish green.
Occurs in distinct granular concre-
tions, or in rounded masses.
Structure foliated. Fracture im-
perfectly conchoidal. Lustre shin-
ing, translucent, and, sometimes,
transparent. Its constituents are,
silex 50-0, magnesia 8 7' 5, oxide
iron 12-0, lime 0*5. It is found
in basalt, and is a constituent of
many lavas.

O'MBRIA. (from opppio*, rain, Gr.)
Fossil echini, to which the name of
ombria has been given, from a sup-
position that they fell from heaven
in the midst of heavy rain ; they
are of a rounded form, and have
been compared to turbans.

OME'NTUH. (omeutum, Lat.) The
caul.

OMNI'VOEOUS. (from omnis, all, and

voro, to devour, Lat.) Animals
which eat food of all kinds.

O'MOPLATE. (from w^o?, the shoulder,
and TrXaTi*?, broad, Gr.) The scap-
ula, or shoulder-blade.

O'NCHVUS. A genus of sharks, belong-
ing to the sub-family of Hybodonts.
The genus onchus, says M. Agassiz,
is easily distinguished. It em-
braces certain cartilaginous fishes,
the dorsal spines of which only
have been discovered. The dorsal
fins are large at their base, very
much bent backwards, narrowing
rapidly towards the superior end,
furrowed along the whole of their
surface by grooves parallel to the
posterior margins, between which
pretty strong ribs rise up, which so
terminate as to give the anterior
edge a toothed aspect. The onchus
arcuatus is the species thus de-
scribed, and is the largest species
of the old red system, though in-
ferior in size to some species of the
carboniferous limestone. — Murchi-
son. Teeth of the onchus have
been found in the lias, at Lyme

ONTO'LOGY. The science of organic
beings; divided into zoology, the
science of animals; botany, the
science of vegetables ; or again
specifically divided into Cainon-
tology, the science of now living
organic beings, and Palaeontology,
the science of extinct organic bodies.
— Jukes.

O'NYX. (from oWg", Gr. a nail, onyx,
Fr.) The quartz agathe onyx of
Hatiy. A variety of calcedony
having different colours arranged
in distinct parallel stripes or zones,
and consisting of alternate layers
of white and brown calcedony.
The onyx is used by lapidaries in
the formation of cameos.

O'OLITE. (from woi>, an egg, and
X/009, a stone, Gr. oolites, Fr.) The
Calcaire de Jura, Calcaire Juras-
sique of the French ; the Oolithen-
bildung, Jurakalk of the Germans.

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A group of strata, whose order of
superposition is below the Purbeck
and above the lias : called also the
Jura limestone from the extensive
chain of the Jura mountains being
principally composed of lias and
the oolitic series. The two lowest
members of this group, or those
immediately above the lias, are
called the great oolite, and the
inferior oolite. All the members
of the group are marine deposites.
The oolite has been thus named
from its being composed of spherical
granular concretions, supposed to
resemble the roe, or eggs, of a fish :
it is a mere term of convenience,
like those of carboniferous, red
sandstone, &c., for many limestones
in other groups are oolitic, while,
on the other hand, this mineralogi-
cal character is found only in an
insignificant part of the rocks
known as the oolite formation in
England and France. The oolite
is an accumulation of sands, sand-
stones, marls, clays, and limestones,
ranging across our island from
Dorsetshire on the south-west, to
Yorkshire on the north-east. The
central members of this group
occupy the high districts of Oxford-
shire and Gloucestershire. A very
striking zoological feature of this
group is the immense abundance of
ammonites and belemnites which
must have existed previous to, and
during its deposit; for, notwith-
standing the usual chances of de-
struction to which we may suppose
they were exposed, myriads of
their shells have been found en-
tombed entire, and not unfrequently
the animal must have been in them.
One hundred and seventy-three
species of ammonites, and. sixty-five
species of belemnites have been
enumerated as discovered in the
polite. There can be little doubt
that this group, greatly expanded
in thickness, and mixed with sand-
stones, marls, and slates, possessing

[ 325 ] 0 0 L

a very different aspect from the
equivalent rocks in a large portion
of Western Europe, extends over
various parts of Eastern Europe.
The aggregate average thickness of
the oolite may be estimated at 1200
feet. In some instances, the spher-
ical granular concretions, which are
imbedded in many of the strata,
attain the size of a pea, and this
variety has obtained the name of
pisiform oolite. Some oolites have
been used for building-stone, but
they are said not to be durable.
Somerset House is built of oolite.
The vertebrated animals, whose
remains are found in oolite, are
fishes and reptiles of the same
genera as those discovered in the
lias. Mammalia have been found
at Stonesfield in Oxfordshire, where
there are the remains of more than
one species of Didelphis. Ptero-
dactyles have been discovered at
Solenhofen (where there would
appear to be many species), at
Lyme Eegis, in Dorsetshire, and
at Banz, in Bavaria. Some strata
of this group are composed, almost
entirely, of madreporites, and these
have been called " coral ragg."
Other strata abound in the remains
of fossil alcyonia and sponges, and
with congeries of minute millepores
and madrepores. In England, the
limestone of the oolite has a yellow-
ish-brown, or ochreous colour, by
which it may at once be distin-
guished from the lias ; and the
fossils partaking of the colour of
the limestone, renders it easy to
separate them from the fossils of
the lias. The oolite has been
divided into three formations, the
upper, the middle, and the lower.
These formations, in England,
occupy a zone having nearly thirty
miles in average breadth, extend-
ing across the island from Yorkshire
on the north-east, to Dorsetshire on
the south-west. Between the lower
and the middle division of oolites,

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there occurs a bed of dark blue
clay, called Oxford, or clunch, clay,
the thickness of which has been
stated to be 200 feet. Between
the middle and upper also, there is
found a thick bed of clay, called
Kimmeridge clay, of a thickness
exceeding, in some parts, 100 feet.
The uppermost members of the
oolite group are the Portland beds,
lying immediately under the Pur-
beck beds.

Oolite has been also called roe-
stone, from a supposition of the
older geologist that the globules
contained in it were the petrified
roes of fishes. In the lithographic
limestone of Solenbofen, belonging
to one of the upper members of the
oolite, a great variety of organic
remains is found ; and in the
museum of Count Munster, there
are not fewer than seven species of
flying lizards, six saurians, three
tortoises, sixty species of fishes,
forty-six species of Crustacea, and
twenty-six species of insects, taken
from that deposit.

The oolitic tracts of England
present a broad band of dry lime-
stone surface, rising westward to
elevations of from 800 to 1,400
feet, with escarpments commanding
very extensive prospects over the
undulating plains of lias and red
marl. The whole tortuous line of
oolitic escarpment from the Humber
to the Avon, may be regarded as
the wasting effects of water on the
subjacent red marls and lias clays.
— BakewelL De la Beche. Lyell.
Cleaveland. Mantell. Phillips.
Conybeare.

OOLIT'IC. Composed of oolite ; re-
sembling oolite. The name of a
large group of strata commencing
with the Portland beds above, and
terminating in the inferior oolite
below.

OOLI'TIC PEB'IOD. Called also the
Jurassic period. The Oolitic period ,
i« comprised in the secondary or

Mesozoie epoch, and is placed
between the cretaceous and triassic
periods. The series of rocks de-
posited in the British isles during
the Oolitic period is so complete
both petrologically and palaeonto-
logically, that they serve for a
type for those known all over the
world.

OOLITI'FEROTJS. Producing oolite, or
roe-stone.

OPA'CITT. (opacitas, darkness, Lat.
opacite, Fr. opacitd, It.) Opaque-
ness; darkness. The quality of
opacity is not a contrary or antago-
nist quality to that of transparency,
but only its extreme lowest degree.

OPAL. The quartz resinite of "Werner ;
untheilbarer quartz of Mohs; a
sub-species of indivisible quartz.
Of this there are many varieties,
the principal of which are, —
1. The precious opal, a milk-white
variety, with a beautiful play of
various rich colours. The play of
colours is supposed to be caused by
numerous minute rents that tra-
verse this mineral ; thin layers
being contained in them, which
have the property of reflecting the
prismatic colours. The precious
opal is sometimes imperfectly imi-
tated by artificial glasses ; and
substances which resemble the opal
in its play of colours are said to
opalesce. 2. Fire -opal ; a trans-
parent variety, brought from Mexi-
co, with a carmine-red and apple-
green iridescence of great beauty.
Found also in Hungary and Corn-
wall. 3. Common opal; a variety
differing but little from the precious
opal in many of its characters, but
not presenting that effulgence, or
play of colours, by which the
precious opal is distinguished. Its
colour is white, shaded with grey,
green, or yellow, sometimes milk-
white. WTien viewed by trans-
mitted light, the milk-white and
greenish varieties often change
their colours. These varieties con-

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stitute the Opal resinite Girasol of
the French mineralogists. 4. Semi-
opal ; a feebly translucent variety,
having a conchoidal fracture ;
colours white, grey, and brown.
Prof. Ehrenberg states that nodules
of semi-opal, which occur in the
Poliers-chiefer, are composed of
silex derived from infusorial re-
mains that have been dissolved and
formed into silicious concretions,
having dispersed through them
numbers of infusorial shields, par-
tially dissolved, together with
others that are unaltered. Ehren-
berg also thinks that he has found
indications of microscopic organic
bodies of a spherical form in semi-
opal from Champigny, and also in
semi-opal from the dolerite of Stein-
heim, and in precious opal from
porphyry of Kaschan. 5. Menilite;
a variety occurring in small, irreg-
ular, roundish masses, often tuber-
ose, or marked with little edges on
the surface. The exterior is often
bluish or striped, but the interior
has a brown or dark grey appear-
ance. Fracture conchoidal. It is
translucent. 6. Mother of pearl
opal or Cacholong. 7. Jasper opal.
8. Wood opal. For details of these
varieties, see the several words.
These varieties consist of silex in
various proportion, from 86 to 95
per cent., combined with oxide of
iron and water. Specific gravity
2-09. Not sufficiently hard to
give fire with steel. The semi-opal
contains about 3 per cent, of
alumina.

OPALE'SCENT. Resembling opal ; ex-
hibiting a play of various colours ;
displaying iridescence.

O'PALIZED. Converted into a sub-
stance resembling opal.

O'PALIZED WOOD. This has the form
and texture of wood ; the vegetable
matter having gradually given
place to a silicious deposite posses-
sing the characters of semi- opal.
Its texture is fibrous j fracture con-

choidal, with a moderate lustre,

It does not strike fire with steel.

Specific gravity between 2-0 and

2*6. Colours white and grey, often

shaded with yellow or red, and

passing into yellow or brown.

Translucent at the edges.

OPAQUE. ") Not transparent ; not per-

OPAKE. j mitting the passage of

rays of light.

OPE'BCULAR. Having a lid, or cover,
or operculum.

1. A lid, by means of which many
of the molluscous animals close the
aperture of their shells. It is in
some animals testaceous ; in others,
horny or cartilaginous. It is af-
fixed to the animal. The opercu-
lum of multivalves is composed of
two or four pieces. The operculum
is calculated for the protection of
the animal when it retires within
its dwelling, of which it may be
termed the door ; it is adapted to
the shape of the aperture, which it
closes completely. The cartilagi-
nous operculum of the common
periwinkle is a familar example.

2. The flap which covers the gill,
or organ of respiration in fishes.

OPHI'DIA. (from o'0ts, a serpent, Gr.)
The third order in the class Repti-
lia, in Cuvier's arrangement, com-
prising three families, Anguina,
Serpentia, and Nuda. In the
structure of the skeleton of the ser-
pents, the first of the true reptiles,
we may observe a beautiful illus-
tration of the simple means employ-
ed in organic structures to accom-
plish the most numerous and diver-
sified ends, and of the resources of
nature in adapting the forms of
bones, in all their essential and
common parts, to the various uses
the animal is to make of them in
the living state. "We have here
animals destitute of anterior and
posterior extremities, destitute of
arms and legs, of handi and feet ,

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L

yet capable of a great variety of
those active movements which we
see in animals the most gifted
with those parts. We see them as
if running on all fours, pursuing
their prey, rapidly winding through
the turf, and through the low
vegetables that cover extensive
plains. If the prey, to escape
from danger, betake itself to the
trees, imagining there to be in
safety, we find these serpents wind-
ing round the tree, and almost
without any apparent motion of
any portion of their trunk, gliding,
as if they were sticking by suckers,
up the trunks of the trees they
climb, till within reach, and then
with a velocit)7, like an elastic
spring let loose, they dart forward
and twine round their prey. If
their prey should even rise from
the ground into the air, we see
these serpents, as if they were
gifted with wings, spring with
velocity from the ground, dart
upon the bird and seize it, or if the
animal be a quadruped, and plunge
for safety into the water, the ser-
pents still pursue it in that
element, swimming like fishes.
Yet, when we examine the condi-
tion of the skeleton, we find it
simply to consist of a vertebral
column and ribs ; and with that
simple condition of the solid in-
ternal frame-work, we see all those
varied movements effected. The
spine of serpents is formed of a
great number of vertebrae ; in the
rattle-snake there are about two
hundred, and in the coluber natrix
above three hundred have been
counted. These vertebrae are all
united by ball and socket joints,
the posterior rounded eminence of
each vertebra being received into
the anterior surface of the next.
Serpents swallow their prey entire ;
and it is well ascertained that they
will swallow animals having ten
times the diameter of that of their

5 ] 0 P H

own neck. The loose connexion
of all the bones surrounding the
mouth of serpents, enables them to
distend their jaws and mouth to
receive undivided prey, and thus,
so far as food is concerned, to dis-
pense with arms to grasp it, and
assist in its sub-division. Neither
are their teeth suited for mastica-
tion, being conical, slender, sharp,
osseous, and recurved.

Venomous serpents, or those with
isolated fangs, have their organs of
manducation constructed on a very
peculiar plan. Their superior max-
illary bones are very small, at-
tached to a long pedicle, and are
very moveable ; in them is fixed
a sharp-pointed pervious tooth,
thro ugh which flows a liquor which,
poured into the wound made by
the tooth, produces effects according
to the species of the reptile se-
creting it. This tooth, when the
animal does not wish to use it, is
concealed in a fold of the gum, and
behind it are several germs desti-
ned to replace it, in the event of
its being broken.

All those venomous serpents,
whose mode of production is well
ascertained, bring forth living
young ones, as their eggs are
hatched without being laid. In
more modern classification ophidia
constitutes the seventh order of
Reptilia, comprising Coluba, and
the extinct genera Palaeophis and
Paleryx.

OPHI'DIOUS. Belonging to the order
Ophidia.

OPHI'OLITE. (from o'0ts, a serpent,
and X/0os, a stone, Gr.) Another
name for mineral serpentine.

OPHIOMO'RPHA. The fourth order of
the class Amphibia, comprising
Cecilia, or the blind worm.

O'PHITE. (o'^rnys, lapis in modum
serpentis maculosus, db o'0ts, a
serpent, Gr.) Green porphyry, or
serpentine. A green-stone, vary-
ing from blackish-green to pistachio

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[S29 ]

ORC

green. It contains greenish -white
crystals of felspar, which on the
polished surface often shew them-
selves in parallelograms, and are
sometimes cruciform. It occurs
massive and disseminated. Lustre
glistening and resinous. Fracture
conchoidal, and often splintery.

OPHITJ'EA. A genus of fossil radi-
aria, of the order Ophiuridse, found
in the lias of Yorkshire and in the
inferior oolite sands near Bridport;
in the oolite of Germany, in the
muschel kalk, in the red sandstone
group, in the upper lias, and in
the upper chalk.

OPHUI'BIDJE. The third order of the
class Echinodermata.

OPI'STHOBRANCHIATA. The sixth order
of the class Cephalophora, com-
prising Tornatella, Bulla, Doris,
Aplysia, &c.

OPO'SSUM. A genus of quadrupeds
belonging to the order Marsupialia.
The opossums are peculiar to
America, and are remarkable for
their number of teeth, amounting
in all to fifty. They approach the
quadrumanes, by having the thumb
of their hind foot opposed to the
fingers, whence they have been
called pedimanes : the thumb is
not armed with a nail.

OBBI'CULA. (from orlis, an orb, Lat.)
A genus of bivalve shells, fossil
and recent, belonging to the family
Brachiopoda. The orbicula is a
very small inequivalved flat bi-
valve; the lower valve very thin,
and adherent to other bodies.

OBBI'CFLAB. (orbiculaire, Fr. orbico-
Idre, It.) Spherical; circular;
roundish and flat. In botany,
leaves are so called when their
length and breadth are equal, and
their form nearly circular.

O'BBIT. (orlita, Lat. orlite, Fr. drbita,
It.) The line described by the
revolution of a planet ; the path of
a planet, or of a comet. The mean
distance of a planet from the sun
is equal to half the major axis of

its orbit. A planet moves in its
elliptical orbit with a velocity
varying every instant, in conse-
quence of two forces, one tending
to the centre of the sun, and the
other in the direction of a tangent
to its orbit, arising from the primi-
tive impulse, given at the time
when it was launched into space.

OEBTJLI'TES. A genus of foraminated
polypifers, differing from lunulites
in having pores on both sides. Mr.
Parkinson thus describes the genus:
*' a free, circular, stony polypifer;
flattish ; pores on both sides, or at
the margin ; resembling nummu-
lites. Set with minute pores,
sometimes scarcely visible, regularly
disposed, but not in spiral order."
The species are nearly all fossil
but some are recent."

OBCHI'DE^. (from o'/>Xts> Gr. orchis,
Lat.) An order of monocotyle-
donous plants. Perianth superior,
sepals three, usually coloured, the
odd one uppermost, from the twist-
ing of the ovarium ; petals three,
usually coloured, of which two are
the uppermost, while the third,
called the labellum, is usually lobed,
and differs in figure, colour, or size,
from the other two, and is often
spurred; stamens three, united in
a central column, the two lateral
generally abortive, the central one
perfect; anther persistent or decid-
uous; pollen either powdery or
cohering in granular or waxy
masses; ovarium one-celled, with
three parietal placenta ; style
forming part of the column of the
stamens ; stigma a viscid space in
front of the column ; fruit usually
a capsule, dehiscing by three valves,
sometimes baccate ; seeds numer-
ous, testa loose and reticulated, no
albumen, embryo a solid undivided
fleshy mass; herbaceous plants,
either stemless, or forming a kind
of tuber above ground; or some-
times with a true stem; leaves
fiimple and entire, sometimes artic-

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ulated with the stem ; inflorescence
terminal or radical spikes, racemes
or panicles, occasionally solitary.

Natives of all countries, except
very cold or very dry. There are
thirty-seven British, and, probably,
altogether not fewer than fifteen
hundred species.

The flower of the orchidese is very
peculiar; the calyx and corolla
consist of three pieces each, and
one of those forming the latter,
differs very greatly in size and form
from the other two; it is called
the labellum, or little lip, and is
often spurred. In many species,
this resembles an insect, and hence
they have received the name of bee,
fly, spider, &c., &c.

OECHI'DEOTJS. Belonging to the order
Orchideae ; parasitical plants.

O'EDEE OP STJPEEPOSI'TION. That ar-
rangement of strata in which they
are invariably found. The order
of superposition is never inverted.
Strata are frequently absent, but
the order of superposition of such
as are present is invariably the
same.

OEE. (erz, Germ.) A metallic com-
pound. Metals are found usually
combined with other substances :
the compounds they thus form are
called Ores, when the metal exists
in them in sufficient quantities to
form a considerable portion of the

OEGA'NIC. (opyaviicos, Gr. organicus,
Lat. organique, Fr. orgdnico, It.)
Consisting of various^parts co-oper-
ating with each other; consisting
of natural instruments of action or
operation.

OEGA'NIC BO'DIES. Such as possess
natural instruments of action; on
the action of each, and their co-
operation together, depend the
growth and perfection of the body.

OBGA'NIC BEMAI'NS. The relics of what
were once living bodies : generally
applied to the fossil remains of
animals or plants.

" Chemical analysis," says Mr
Parkinson, " has been called in to
the aid of the naturalist, in order
to account for the perfect state of
preservation observable in remains
organized with the most exquisite
delicacy, and which there is every
reason for supposing to have been
decomposable in their recent state.
From this investigation we learn
the manner in which these memo-
rials of the old world, so interesting
and so frail, have been preserved.
Some have been impregnated with
calcareous matter, others with sili-
cious, and others with iron and
copper pyrites."

OEISK'ANY SANDSTONE. A member of
the North American Devonian
rocks, attaining a thickness of 200
feet, and by its fossils proved to be
contemporaneous with the Lower
Devonian group of the Rhine.

OEISMO'LOGY. (from qpto/to?, defini-
tion, and Ao'ryos, discourse, Gr.)
Called also terminology. In ento-
mology, orismology contains the
various technical terms used in
explaining the perceptible differ-
ences in the body of an insect, and
at the same time acquaints us with
its exterior visible parts in the
several periods of its existence,
until its full and perfect develop-
ment. It is the very first requisite
of a precise orismology to apply an
exclusively proper term to each
constantly distinct and peculiar
part.

OENITHI'CKNITES. (from opvis, a bird,
and 0/70), to touch, Gr.) The
footmarks of birds found in differ-
ent formations. Some recent dis-
coveries of ornithicknites are very
remarkable; the footsteps appear
in regular succession, on the con-
tinuous track of an animal in the
act of running or walking, with
the right and left foot always in
their relative places. An account
of these has been published by Prof.
Hitchcock, in the American Jour-

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nal of Arts and Sciences : they
were discovered in the new red
sandstone of the valley of Connecti-
cut. The most remarkable were
those of a gigantic bird, twice the
size of an ostrich, whose foot mea-
sured fifteen inches in length, ex-
clusive of the largest claw, which
measured two inches. The dis-
covery of these ornithicknites is
exceedingly interesting to the pal-
aeontologist, as proving the exist-
ence of birds at the early epoch of
the new red sandstone formation.

OBNI'THOLITE. (from opvn, a bird,
and \j0os, a stone, Gr.) A fossil
bird. Stones of various colours
and forms, bearing the figures of
birds. Specimens of this kind may
be obtained at Matlock, in Derby-
shire, and at other places where the
water is surcharged with lime.
The gypsum quarries of Paris con-
tain the debris of birds in great
abundance. The feet are the most
remarkable part in all the ornitho-
lites, the feet of birds being com-
posed in a peculiar way, not
resembling those of any other
animals.

OBNITHO'LOGY. (from opvis, a bird,
and XJcyos, discourse, Gr.) That
department of natural history which
treats of birds; describes their
structure, external and internal ;
and teaches their economy and
their uses.

OBNITHO'LOGIST. One versed in that
branch of natural history which
treats of the habits, structure and
uses of birds.

OBNITHORHY'NCHUS. (from opvi?, a

- bird, and pvy-xps, a beak, Gr.)
The platypus of Shaw. The duck-
bill ; an animal indigenous to New
Holland, and found in no other
country. In this anomalous ani-
mal, we have a quadruped clothed
with fur, having a bill like a duck,
with four webbed feet, suckling its
young, and most probably ovo-
viviparous : the male is furnished

with spurs. The mouth of the
ornithorhynchus has a form of con-
struction between that of quadru-
peds and birds, being furnished,
like the former, with grinding teeth
at the posterior part of both the
upper and lower jaws, but they are
of a horny substance; the mouth
is terminated in front by a horny
bill, greatly resembling that of the
duck, or the spoon-bill. It has
also small cheek-pouches. Mem-
branes unite the toes of the fore
and hind- feet; in the fore-feet it
extends beyond the nails, in the
hind-feet it terminates at the root
of the nails. It has also a flattened
tail. It inhabits the rivers and
marshes.

O'RPIMENT. (from auripigmentum, Lat.
orpiment, Pr. orpimento, It.) The
Arsenic sulfure jaune of Hauy;
Arsenic sulfur^ orpiment of Brong-
niart. Yellow sulphuret of arsenic,
an ore of arsenic combined with
sulphur. Its colour is usually
lemon-yellow, which is often shin-
ing and beautiful. It occurs in
laminated or lamellar masses ; in
concretions; and sometimes in
minute crystals. It is principally
volatilized before the . blow -pipe,
with a white smoke, and with the
odour of both sulphur and arsenic,
leaving a small earthy residue.
According to Thenard it is composed
of arsenic 57, sulphur 43.

O'BTHIS. (from opQos, straight, Gr.)
A genus of fossil shells, constituting
a division of spirifer, but distin-
guished from spirifer by the long
narrow hinge and circular flat form
of the striated shells. Twenty-six
species of the genus orthis are
enumerated by Sir R. Murchison
as occurring in the Silurian rocks.

O'BTHITE. A mineral found in the
mine of Finbo, in Sweden, and
thus named from its being always
found in straight layers.

OBTHO'CERAS. } (opOos, straight,

OBTHOCE'BATITE. ) and *£/>«?, a horn,

GET

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OSS

Gr.) An extinct genus of poly-
thalamous, or many chambered,
cephalapods, which inhabited
straight shells. The orthoceratite
resembles an ammonite unrolled,
having its chambers separated by
transverse septa, concave externally,
and convex internally ; the septa
being pierced by a siphuncle.
Orthoceratites are abundantly found
in the transition strata, appearing
to have been early called into
existence, and at an early period to
have been consigned to almost total
destruction. At the close of the
Triassic period the Orthoceras ap-
pears to have become extinct. It
is regarded as characteristic of the
Palceozoic strata. Part of the
pavement of the palace at Hampton
Court, and that of the hall of Uni-
versity College, Oxford, are com-
posed of marble containing remains
of orthoceratites. Some species,
found in the carboniferous limestone
of Closeburn, in Dumfries-shire,
are nearly the size of a man's
thigh.

OBTHOCOS'L A. A group of animalcules,
thus named from the straight
course of the intestine.

O'BTHOCLASE. Called also potash-
feldspar; a mineral consisting of
silica 65*35, alumina 18'06, pot-
ash 16-59.

OETHO'PTEEA. (from opOos, straight,
and Tnepov, a wing, Gr.) An order
of insects, the sixth in Cuvier's
arrangement. The coverings of the
wings, instead of being of a horny
texture, are soft and flexible. The
wings themselves, being broader
than their coverings, are, when not
in use, folded longitudinally like a
fan.

O'ETHOSE. The name of a feldspathic
mineral.

OEYCTOLO'GICAL, (from opvieros, a
fossil, and XoVyos, discourse, Gr.)
Pertaining to that part of physics
which treats of fossils.

OEYCTO'LOGIST. One who studies, or

is versed in, that part of physics
which treats of fossils.

OEYCTO'LOGY. (from opvicros, a fossil,
and Xo<yos, discourse, Gr.) Oryc-
tology is that branch of mineralogy
which has for its object the classifi-
cation of fossils ; or, in other words,
it consists in the description of
fossils, the determination of their
nomenclature, and the systematic
arrangement of their different
species. Oryctology has also been
defined as the science which en-
quires into the nature, origin, and
formation of those bodies which
possess the figures, markings, or
structure of vegetables, or animals,
whilst their substance evinces their
having been preserved through
many ages, by certain changes
effected in subaqueous or subterra-
nean situations.

OSCILLATION, (oscillatio, Lat. oscilla-
tion, Fr. oscillazione, It.) Vibra-
tion ; the act of swinging to and
fro ; a movement to and fro, like
the swinging of the pendulum of a
clock, or waves in water. The
tides are oscillations of the sea.

OSMEEO'IDES MANTE'LLII. The name
given by Dr. Mantell to an ichthy-
olite of the chalk formation discov-
ered in the Lewes chalk-pits. It
is closely related to the smelt.

O'SMITTM. (from oefir), odour, Gr.)
A metal discovered by Tennant in
crude platinum, and deriving its
name from the strong odour emitted
by some of its compounds. Its
symbols are 0. S. ; specific gravity
10-00.

O'SSEOTJS BEE'CCIA. A mass of frag-
ments of the bones of animals, ce-
mented together by a calcareous
gangue, and commonly found in
fissures and caves.

O'SSICLE. (pssiculum, a little bone,
Lat.) A small bone.

OSSI'FEEOUS. (from os, a bone, and
feroy to produce, to bear, or contain,
Lat.) Yielding bones or fragments
of bones ; containing bones. Thus

0 S T

[ 333 J

OVA

we have ossiferous gravel, ossiferous
clay, ossiferous strata, ossiferous
caves, &c., &c.

OSTEOCO'LLA. (from cxneov, a bone,
and Ko\\a, glue, Or.) Vegetables
of the most delicate texture, when
immersed in waters containing car-
bonate of lime, become incrusted,
still preserving their form even to
their most delicate ramifications.
These incrustations somewhat re-
semble the bone of an animal, and
the property has been absurdly at-
tributed to them of facilitating the
union of fractured bones.

OSTEOLE'PIS. (from osreoi/, a bone,
and XeTrts, a scale, Gr.) The name
assigned by Mr. Pentland and M.
Valenciennes to a genus of fossil
fishes, found in the old red sand-
stone of Scotland. Six species
have been described. Sir R. Mur~
chison states that this genus has
not hitherto been discovered in the
old red sandstone of England. The
osteolepis had a shell as naked as
its teeth, the bone being merely
covered by a hard shining enamel ;
its toes also were of bare enamelled
bone. The enamelled teeth were
placed in jaws which presented
outside a surface as naked and as
finely enamelled as their own. The
entire head was covered with enam-
elled osseous plates, furnished in-
side, like other bones, with their
nourishing blood vessels. The fins
had a sort of bird-wing construction.
The mouth opened below the snout,
but not so far below it as in the
purely cartillaginous fishes. It was
thickly furnished with slender and
sharply-pointed teeth. The gills
opened, as in the osseous fishes, in
continuous lines, and were covered
by large bony opercules. "While
the head and its appendages re-
sembled, in some points, the bony
fishes, the tail differed in no respects
from the tails of cartilaginous ones.
In size, the osteolepis varied from
six to twelve inches.

OSTEO'LOGY. (from ooreoi/, a bone,
and Xo'709, discourse, Gr.) A des-
cription of the bones ; that part of
anatomy which treats of the bones.
That branch of science named fossil
osteology has assumed a most im-
portant character, for which we are
mainly indebted to the labours of
Cuvier. From a single fragment
of a bone, certainly of a character-
istic part, the order and genus of
the animal may be determined with
a precision amounting almost to
mathematical certainty.

OSTEO'LOGICAL (from Osteology.)

OS'TRACITE. A fossil oyster.

OSTRA'CODA. The fifth order of the
class Crustacea, comprising Cypris
and Cythere.

OSTRJS'A. j The oyster. A rough,

OS'TREA. ) adherent, inequivalved
bivalve ; the hinge without a tooth.
One muscular impression in each
valve. The oyster is found both
fossil and recent. Of this genus,
one hundred and thirty-seven spe-
cies have been described in Turton's
Linne. The most extraordinary
shell of this genus for size, says
Mr. Parkinson, is the large fossil
oyster, the recent analogue of which,
from Virginia, appears to be de-
picted by Lister. Some attain to
the length of twenty inches. An
under valve in Mr. Parkinson's
possession weighed four pounds,
being thirteen inches in length and
three in thickness.

OUTCROP. A term, used by miners, to
express the exposure at the surface
of a stratum or strata.

OU'TLIEK. A portion of a stratum
detached from the principal mass,
and lying detached at some distance
from it.

O'VA ANGTJI'NA. A species of fossil
cidaris or echinus.

O'VAL. (from ovum, an egg, Lat, ovafo,
Fr. ovdle. It.) A rounded surface,
its two right-angular diameters be-
ing of an unequal length, so that
its longest transverse diameter does

OVA

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0 X Y

not pass through the centre of its
longitudinal diameter, but lies
nearer to one end : egg-shaped.

OVA'RIUM, ) (ovaire, Fr. ovaja, It.)

O'VARY. ) That part of the body
which contains the ova, and in
which impregnation is performed.
In animals, it is only in the
organs termed ovaries, that ova are
formed.

In botany, that part of the flower
which ripens into the fruit, and
contains the seed.

O'VATE. (ovatus, made like an egg,
from ovum, Lat.) Of the shape of
an egg ; egg-shaped.

OVIDTTCT. (from ovum, an egg, and
ductus, a passage, Lat.) A canal,
or duct, through which the ova
pass, after impregnation, from the
ovary to the uterus. In the human
subject the oviducts are called the
Fallopian tubes.

O'VIFORM. (from ovum, an egg, and
forma, shape, Lat.) Of the form
or shape of an egg.

OVI'PAROUS. (from ovum, an egg, and
pario, to produce, Lat. ovipare, Fr.
oviparo, It.) All animals which
lay eggs, enclosed in a calcareous
shell, are called oviparous. Ovi-
parous production is thus charac-
terized; the young animal is not
attached to the parieties of the ovi-
duct, but remains separated from it
by its external envelope ; its aliment
being enclosed in a sac, which
is attached to its intestinal
canal.

OVO'-VIVIPAROUS. Producing young
in an egg, which is hatched inter-
nally, and previously to exclusion
by the parent. Some animals,
such as the salamander and the
viper, never lay their eggs, but
these are hatched within the body
of the parent; so that although
originally contained in eggs, the
offspring are brought forth in a
living state. Such animals are
termed ovo-viviparous.

OVIPOSITOR, A name given to the

terminal apex of the abdomen of
insects.

O'VULE. } (dim. of ovum, an egg,

O'VULUM. ) Lat.) In botany, the
seed before it is perfected. The
small bodies produced on the mar-
gins of the carpella in the pistil,
are called ovula, or ovules ; when
perfected, they become the seed of
the plant. The ovule is generally
attached to the placenta of the
ovarium by a very small stalk.

OVULI'TES. A genus of foraminated
polypifers, said to be known only
as fossil, of minute size, not ex-
ceeding two millimetres in length.
Ovulites is a stony, free, oviform,
or c}7lindrical, polypifer ; hollow
within; the extremities generally
perforated, having minute pores
regularly diffused over the surface.

O'XFORD CLAY. Called also ciunch clay.
A bed of dark blue clay, sometimes
nearly six hundred feet in thick-
ness, interposed between the lower
and the middle oolites.

OXIDA'TION. That process by which
metals, and other substances, are
converted into oxides by their com-
bination with oxygen.

O'XIDE. | A substance combined with

O'XYDE. ) oxygen, without being in
the state of an acid.

O'XIDIZED. Converted into an oxide,
by combination with oxygen.

O'XYGEN. (from o£i>9, acid, and
ryei/vau;, to produce, Gr.) So called
from its property of forming acids.
One of the simple or elementary
substances, and one of the five
which exist as gas. So generally
does oxygen enter into combination
with metallic and non- metallic
bodies, and in such large propor-
tions, that it has been computed
that one-half of the ponderable
matter of the globe is composed of
oxygen gas. Oxygen constitutes,
by measure, 21 per cent, by weight
23 per cent, of the volume of the
atmosphere ; it forms a third part,
by measure, of the gasses composing

PAG

C 335 ]

P A C

pure water; and is locked up to
an immense amount in the various
rocks, which are little else than a
mass of oxidized substances. Plants
give out oxygen, animals absorb it.
It is to Dr. Priestley we owe the
knowledge of the former of these
two facts ; and he it was who first
discovered oxygen, in 1774. Oxy-
gen has neither taste nor smell. It
is a trifle heavier than atmospheric
air, 100 inches weighing 33.88
grains. The combining proportion,
or equivalen number of oxygen,

that of hydrogen being taken as
unity, is 8 ; its symbol, 0.

OXYQENA'TION. "This word," says
Dr. Tire, "is often used for oxi-
dation, and frequently confounded
with it ; but it differs, in being of
more general import, as every union
with oxygen, whatever the pro-
duct may be, is an oxygenation;
but oxidation takes place only when
an oxide is formed."

O'YSANITB. A name given by Lameth
to pyramidal titanium, or ana-
tase.

PACHYDE'EMATA. (from va^vv, thick,
and Seppa, skin, Gr.) Thick-skinned
animals. The seventh order of the
class Mammalia, in Cuvier's ar-
rangement. This order Cuvier di-
vided into two families, namely,
Proboscidian a, or those pachyder-
matous animals, which have tusks
and a proboscis, as the elephant
and mastodon; and pachydermata
ordinaria, in which are included
the hippopotamus, anoplotherium,
palaeotherium, tapir, &c.

Several genera of the order Pa-
chydermata have become extinct,
their fossil remains alone proving
that such ever existed. Amongst
these are the mastodon, the ano-
plotherium, the palaeotherium, the
lophiodon, the anthracotherium,
the cheropotaraus, adapis, &c. Of
these there are about forty species,
all extinct, and to which there are
none analogous in the living world,
except two tapirs and a daman.
Of the existing genera of pachyder-
mata, many species which existed
during the older and newer pliocene
periods also seem to have become
extinct, and, in fact, the living
species bear no sort of proportion

to the extinct. Those shades which
approximate genera to each other,
those intermediate forms, those
steps from one genus to another,
so common in the other families of
the animal kingdom, are here
wanting. It was reserved for the
science of fossil osteology to recover
them from the entrails of the eatth,
among the races which completed
the grand system of animated na-
ture, and whose destruction has
produced such wide and striking
intervals.

The pachydermata appear to be,
as it were, only the remnants of a
very extensive order, which for-
merly inhabited the earth, but have
now almost entirely disappeared.
They feed upon grass, but they do
not ruminate. They are, for the
most part, huge and unwieldly
animals, with thick integuments;
solidity and strength appear to be
the objects chiefly regarded in their
construction.

PACHY'MIA. A genus of fossil bivalve
shells described by Mr. Sowerby
as obliquely elongated, equivalve,
thick, sub-bilobed, with beaks near
the anterior extremity; the liga-

P A C

336 ]

PAL

ment partially immersed, attached
to prominent fulcra. Its place in
the conchological system has not
been determined with certainty ;
the P. gigus is found in the green
sand of Lyme Regis. — Lycett.

PACHYBI'SMA. A fossil genus of
thick equivalve, inequilateral bi-
valves, belonging to the Cardiacese
of Lamarck ; the figure is trans-
verse, oblong or cardiform, the
umbones are large and incurved,
the ligament external, placed upon
prominent fulcra, the hinge is
massive, having a large sub-conical
prominent tooth in each valve, and
a small accessory tooth in the right
valve. — Lycett.

PACHYDERMATOUS. Thick - skinned ;
belonging to the order Pachyder-
mata.

PA'DDLE. The swimming apparatus
of the chelonian reptiles and of the
marine saurians, has obtained the
name of paddles.

P^JCILO'PODA. (from TTOWC/XOS, and
TTOW, Gr. various footed.) The
second order of the class Crustacea ;
it comprises two families, Xyso-
plmra and Siphonostoma.

PALA'GONITE. A mineral; an amor-
phous highly hydrated scapolite.

PAL^O'LOGY. (from n-aXatos, ancient,
and Xo'fyos, discourse, Gr.) The
study of ancient things. This word
is commonly written paleology.

PALEONI'SCUS. The name assigned
by De Blainville to a genus of
fossil fishes or ichthyolites, ap-
proximating to the sturgeons. The
name has also been given to a
genus of insects, and in order to
avoid confusion this latter should,
as applied to insects, be altered.

PAL.&ONTO'LOGIST. (from paleontology . )
One who studies, or is versed in,
the history of fossil plants and
animals.

PALSONTO'LOGY. (from TmXruo*, an-
cient, wv, being, and XoV/os, dis-
course, Gr.) The history of fossil
plants and animals; that branch of

natural history which treats of fos-
sil and extinct animals and plants.

PAL^OSAU/BTJS. (from[7raXcuos, ancient,
and <ravpo<st a lizard, Gr.) A genus
of fossil saurians, now extinct, found
in the magnesian limestone.

PAL^OTHE'EITJM. } (from TraXeuo?, an-

PAL^EOTHE'BE j cient, and Oypt'ov,
a wild beast, Gr.) An extinct
genus of fossil quadrupeds, belong-
ing to the order Pachydermata,
having six incisors in each jaw,
ranged in one and the same line ;
four canines, two in each jaw,
conical, and so distant as to cross
each other when the mouth was
closed ; fourteen molars in each
jaw, the upper of a square form,
with four roots and three crests on
the outer side, leaving between
them two channels ; a furrow on
the inner side ; their coronal nearly
anologous to that of the upper
molars of the daman and rhino-
ceros. The lower molars show
their enamelled outlines in the
form of a double crescent. The
general form of the head is
like that of the tapirs, the
nasal bones, short and slender.
It possessed three toes to each foot,
and had a short fleshy probocis.
"The place of the genus Palaeo-
therium," says Buckland, " is in-
termediate between the rhinoceros,
the horse, and the tapir. Some of
the discovered species were as large
as a rhinoceros, others were from
the size of a horse to that of a hare.
These animals probably lived and
died upon the margins of the then
existing lakes and rivers."

PALJEOTHE'EIAN. Belonging to the
genus Palseotherium, as palaeo-
therian remains, &c.

PAL^O'SPALAX. (from TraXatos, ancient,
and <T7raXa£, a mole, Gr.) " An
extinct genus of insectivore, refer-
able, says Prof. Owen, to the mole
tribe, but as large as a hedgehog.
The only specimen hitherto dis-
covered is in the British Museum,

PAL

[357]

PAL

and was met with in the lacustrine
formation at Ostend, near Bacton,
in Norfolk.

PAL^OTHBI'SSTJM. The name assigned
to a genus of fossil fishes discovered
in the metalliferous schists of
Mansfield, Thuringia, &c. This
genus comprises several species, as
the P. macrocephalum, P. magnum,
P. parvum, and P. ina3quilobum.
Hitherto this genus has been found
fossil only, and in strata anterior
to the chalk.

PALAEOZOIC. Formerly termed pri mary .
The palaeozoic or primary epoch
comprises six periods, namely,
the Cambrian, the Lower Silurian,
the Upper Silurian, the Devonian,
the Carboniferous, and the Per-
mian.

PA'LEA. (palea, chaff, Lat.) In bot-
any, a term applied to the inner
bracteae of grasses : the palese are
membranous or chaffy in texture.

PALLA'DIFM. (from the planet Pallas.)
A metal of a greyish or bluish-
white colour, discovered by Dr.
"Wbllaston in 1803, in platinum.
It is malleable, ductile, and flexi-
ble, but does not possess much
elasticity. In hardness it sur-
passes all other metals, with the
exception of tungsten, which it
equals. Specific gravity 11*8. It
is not oxidated by the action of the
atmosphere. It is fusible only at
a very high temperature. Symbols
Pd.

PA'LLEAL. (from pallium, a mantle,
Lat.) In conchology, the name
given to the mark or impression
observed in bivalves, formed by the
muscular attachment of the mantle.

PA'LLIOBRANCHI'ATA. The same as
-Brachiopoda.

PALM, (from palma, Lat.) The palms
constitute a natural order of mono-
cotyledonous, or endogenous, plants.
The flowers are hermaphrodite, or
polygamous. Perianth six- par ted,
persistent. Stamens inserted into
the base of the perianth, definite or

indefinite. Ovary three-celled, or
deeply three-lobed, with an erect
ovule. Fruit baccate or drupaceous,
with fibrous flesh. Albumen car-
tilaginous ; embryo in a cavity at
a distance from the hilum. Leaves
terminal, large, pinnate, or flabelli-
form, plaited in vernation. Spadix
enclosed in a valved spatha. Flow-
ers small.

A palm tree affords an example
of the mode of growth in endo-
genous plants. The stem of this
tree is usually perfectly cylindrical,
attains a great height, and bears
on its summit a tuft of leaves. It
is composed of an extremely dense
external cylindric layer of wood;
but the texture of the interior
becomes gradually softer and more
porous as it approaches the centre.
It has neither medullary rays, nor
central pith, nor true outward
bark. The first stage of its growth
consists in the appearance of a
circle of leaves, which shoot up-
wards from the neck of the plant,
and attain during the first year, a
certain size. The following year
another circle of leaves arises ; but
they grow from the interior of the
former circle, which they force
outwards as their vegetation ad-
vances, and as ligneous matter is
deposited within them. As soon
as the outer layer has become too
hard to yield to the pressure from
within, the growth of the inner
layers is immediately directed up-
wards; so that they rise in suc-
cession by distinct stages, always
proceeding from the interior; a
mode of development which has
been compared by De Candolle to
the drawing out of the sliding
tubes of a telescope. The whole
stem, whatever height it may
attain, never increases in diameter
after its outer layer has been con-
solidated. A circle of leaves
annually sprouts from the margin
of the new layer of wood ; these,
x x

PAL

[ 338

P A IT

when they fall off, leave traces,
consisting of a circular impression
round the stem. By the number
of these circles the age of the tree
may be ascertained. The existing
family of palms is supposed to
consist of nearly a thousand species,
of which the greater number are
limited to peculiar regions of the
torrid zone.

PA'LMATE. | (palmatus, Lat.) Web-
PA'LMATED. ) bed, like the feet of
some water-birds ; deeply divided
into lobes like the fingers on
the hand ; resembling a hand ;
palmed or hand like. Applied
to leaves which are divided,
half-way, or more than half-way,
down the middle, into several
nearly equal segments, having a
space between each.
PALMI'PEDES. (from palmipes, that
hath its feet closed with a film or
web, Lat.) The sixth order of
birds in Cuvier's arrangement.
The goose and duck are familiar
examples.

PA'LPI. In entomology, the palpi, or
feelers, are the auxiliary organs of
a masticating mouth. Those upon
the maxillae are termed the palpi
maxillares, or maxillary feelers;
those placed laterally upon the
labium, are designated the palpi
labiales, or labial feelers.
PALTJDI'NA. A genus of fresh-water
univalves, belonging to the family
Peristomata. Remains of paludinse
are very abundant in the Sussex
marble, and the P. fluviorum is its
common and characteristic fossil.
PAMPHBA'CTUS. A genus of ichthyo-
lites of the old red sandstone, two
species of which have been de-
scribed by Agassiz. It appears to
have become extinct at the close of
the Devonian period.
PA'NCAKE. The name given by Klein
to the Echinodiscus laganum, a
species of fossil echinus, belonging
to the division Catocysti.

PANDA'NEA. } (frompandus, Lat. crook-
PANDA'NTJS. ) ed.) The screw-pine,
so named from the spiral arrange-
ment of its leaves, is a monocoty-
ledonous tree, growing only in the
warmer zones, and principally near
the sea. The pandanea, like the
cocoa-nut palm, is generally the
first vegetable colonist of the newly-
raised coral islands. Its appearance
is that of a gigantic pine-apple
plant, with arborescent stems. The
pandanus bears a large spherical,
drupaceous fruit : the seed within
each drupe being enclosed within
a hard nut. From the pandanus
growing near to the sea, its fruit
frequently drops into the water,
and is drifted by the waves and
winds to distant shores : thus the
elements of vegetation are trans-
ported to the emerging coral islands,
where it vegetates. A fossil fruit
of the pandanus was found by Mr.
Page in the inferior oolite, and is
in the Oxford museum. It is of
the size of a large orange, and is
covered by a stellated rind, or epi-
carpium, composed of hexagonal
tubercles, forming the summits of
cells, which occupy the entire
surface of the fruit. Fruits of a
genus, to which M. Adam Brong-
niart has given the name of Pan-
danocarpum, occur, together with
cocoa-nut fruit, at an early period
of the tertiary formations, in the
London clay of the Isle of Sheppey.
PA'NGOLIN. A species of manis, or
scaly lizard ; called also the scaly
ant-eater. Its armature is com-
posed of separate, horny, moveable
scales. It is destitute of teeth, has
a very extensile tongue, and lives
on ants and termites.
PA'NICLE. (panicula, Lat. a bunch
or cluster.) A species of inflo-
rescence, in which the flowers are
scattered on peduncles, variously
subdivided without any order, and
more or less close. The oat affords
a familiar example. "When the

PAN

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middle branches of a panicle are
longer than the others, it is termed
a thyrsus.

PANNI'CULUS CAENO'SUS. (from pan-
nioulm, a cloth, and carnosus,
fleshy, Lat.) A peculiar set of sub-
cutaneous muscular bands which
serve to erect the bristles, or
armour of certain animals ; as in
the hedge-hog, porcupine, &c.

PANOPJE'A. A genus of bivalve shells
of the family Solenacea. The
Panopaea is a transverse inequilat-
eral bivalve, gaping at both extre-
mities. The hinge similar in both
valves, with an acute cardinal
tooth in each, and, on the right
valve, a little pit, which receives
the tooth of the opposite valve.
It is found both recent and fossil.

PA'PEE COAL. A bituminous shale,
to which the name has been given
from its divisibility into extremely
thin leaves.

PA'PEE NAU'TILTJS. Called also the
Paper Sailor. See Argonauta.

PAP^LIO. (papilio, Lat. a butterfly.)
A genus of the family Diurna.
belonging to the order Lepidoptera,
The butterfly. The species are
numerous. It has been well ob-
served that the chrysalis is the
tomb of the caterpillar, and the
cradle of the butterfly.

PAPILIOKA'CEOUS. Kesembling a but-
terfly. In botany, the corolla is
called papilionaceous when it con-
sists of five petals of particular
forms, of which the uppermost is
generally the largest, and turned
back ; the two next resemble each
other, and are called the alae ; the
two lowermost are generally united
by their lower edge, and form a
keel-like figure, and are, from that
circumstance, called the carina or
keel; the two last, so united,
contain, and protect, the internal
organs.

PAPI'LLA. (papilla, Lat.) This word
is generally used in the plural,
papillae. Malphigi first discovered

this structure in the foot of the
pig, and gave to it its name. The
external surface of the skin presents
a great number of minute pro-
jecting filaments; these are the
papillae. " It is probable," says
Dr. Eoget, " that each of these
papillae contains a separate branch
of the nerves of touch, so that we
we may consider these papillae as
the principal and immediate organs
of touch. The papillae are much
more easily perceived on some
parts than others, but no where
are they more perceptible than on
the tongue, where, more especially
in a morbid condition of the body,
they are frequently much elevated."

PAPI'LLOSE. In botany, a term applied
to stems covered with soft tubercles;
also to leaves covered with fleshy
dots or points.

PA'PPUS. (pappus, Lat. thistle-down,
TraTrTra?, GT.) The feathery appen-
dage that crowns many seeds which
have no pericarpium ; a particular
form of calyx, of which we have a
familiar example in the dandelion.

PAEA'BOIA. (parabola, Lat.) One of
the five conic sections : thus, if a
cone be cut by a plane parallel to
one of its sloping sides, the section
will be a parabola.

PAEADO'XIDES. The name given by
Erongniart to a genus of trilobites.
The Olenus of Dalman. "This
genus," says Sir E. Murchison,
" may always be recognised by the
ends of all the lateral ribs termi-
nating in deflected points, some of
which extend in spikes beyond the
tail." In Pictet's system, Parad-
oxides constitutes a family com-
prising the genera Remopleurides,
Paradoxides, Hydrocephalus, Jao,
Arionellus, Ellipsocephalus, Olenus,
Conocephalites, Peltura, and Tri-
arthrus.

PARALLE'LOGEAM. (from Tra/mXXi/Xo?
and ^pdfifjLa, Gr. paralUlograme, Fr.
par allelogr ammo, It.) In geometry,
a right-lined quadrilateral figure,

PAR

[ 340 ]

P A It

whose opposite sides are parallel
and equal.

PARALLEL'OPIPED. (parallelipipede, Fr.
terme de giombtrie. Corps solide
termini par six parallelogrammes
dont les opposes sont paralleles entre
eux.j A solid figure contained under
six parallelograms, the opposites of
which are parallel and equal ; or it
is a prism whose base is a parallelo-
gram; it is always triple to a
pyramid of the same base and height.
The term parallelepiped includes, in
mineralogy, all those solids whose
bounding planes are parallel two
and two; as for instance, all the
varieties of the rhomboid ; and all
the prisms of which the terminal
planes are rhombic; and all the
square and rectangular prisms which
do not possess the precise proportions
of the cube.
PABALLELO'PIPEDAL. Having the figure

of a parallelepiped.
PARALLELISM. Nothing is more re-
markable in volcanic dikes than the
parallelism of the opposite sides,
which usually correspond with as
much regularity as the two opposite
faces of a wall of masonry.
PABAMO'UDEA. (The derivation of this
word, says Buckland, I could trace
to no authentic source, but shall
adopt because I find it thus appro-
priated.) A singular fossil body,
found in the chalk of the North of
Ireland. Among the organic
remains of the chalk in the north
of Ireland, are large silicious bodies
of a very peculiar character. These
singular fossils are found in many
of the chalk pits from Moira to
Belfast and Larne, but are most
numerous at Moira. They have,
I believe, never yet been found in
the chalk of England, except at
Whitlingham, near to Norwich,
and at some other places in the
same neighbourhood, whence there
is a good specimen in the collection
of the Geological Society, about
two feet long and one foot in

diameter. The length of these
bodies varies from one to two feet,
their thickness from six to twelve
inches. Their substance in all
cases is flint. The termination of
of these silicious bodies is distinct,
and the separation of the flint from
its matrix ©f chalk always clear and
decided. Their outer covering has
the appearance of a thin epidermis,
smooth externally, and whiter than
the mass of flint enclosed, which is
usually of a dark grey colour.

In all cases these bodies seem to
have had a central aperture passing
into and generally through their
long diameter. The breadth of
this aperture varies in different
specimens.

PAKAMO'BPHISH. The name given to
a particular kind of pseudo-mor-
phism.

PABA'NTHINE. A rare mineral, thus
named by Haiiy, more commonly
known as Scapolite.
PABASI'TA. fparasita, Lat. irapaffno?,
Gr.) In Cuvier's arrangement, the
third order of Insecta; they have
six legs and are apterous. The Rev.
Mr. Kirby observes, "the order of
parasites, consisting of the most
unclean and disgusting animals of
the whole class, infest man,
beast and bird, no less than four
species being attached to man,
may be divided into two sections,
namely, those that live by suction,
and those that masticate their food.
To the first of these belong the
human and the dog-louse, and to
the other the various lice that
inhabit the birds, of which almost
every species has a peculiar one."
PAEASI'TIC } 1. In botany, applied
PABASI'TICAL. j to plants which fix
their roots into other plants, and
from them, instead of from the
earth, derive their nourishment:
the mistletoe is a familiar example.
2. In zoology, a name given to
certain insects which live upon the
animals they infest.

PAR

PARENCHY'MA. (Trapi<yxypa, Gr.paren-
chyme, Fr.)

1. A spongy or porous substance
forming the bulk of some of the
viscera, as the parenchyma of the
liver, &c.

2. In botany, a fine, transparent,
membranous tissue, lying imme-
diately beneath the epidermis of
plants; it is of a deep green
colour, very tender, and succulent.
When viewed with a microscope,
it seems to be composed of fibres
which cross each other in every
direction. In its simplest state, it
appears like a mass of globules or
vesicles, crowded together ; these,
from pressure, assume a six-sided,
or hexagonal figure.

PARENCHY'MATOUS. Consisting of pa-
renchyma; spongy; porous.

PA'EGASITE. The name given to a
variety of actinolite, from its being
found in the Isle of Pargas, in
Finland. Colour forms the princi-
pal difference between hornblende
and pargasite, the latter being
somewhat translucent and of a
lighter green, or more generally of
a bottle-green hue.

PAEIE'TAL. (from paries, a wall, Lat.)

1. The name given to certain bones
of the skull, from their serving as
walls to the brain.

2. In botany, a term used to ex-
press an adhesion of some part to
the inner side of an organ ; as
when the seeds are attached to the
placenta, the latter are termed
parietal.

PA'KTS BA'SIN. A large area, to
which the name of Paris Basin
has been given, about 180 miles
in length, from north-east to south-
west, and about ninety miles wide,
from east to west. The country
in which the capital of France is
situated, is perhaps the most re-
markable that has yet been obser-
ved, both from the succession of
different soils of which it is formed,
and from the extraordinary organic

[ S41 ] PAR

remains which it contains. Bones
of land animals, of which the
genera are entirely unknown, are
found in certain parts ; other bones
remarkable for their vast size, and
of which some of similar genera
exist only in distant countries, are
found scattered in the upper beds.
Millions of marine shells, which
alternate regularly with fresh-water
shells, compose the principal mass.
The strata composing the Paris
basin rest upon chalk, lying, as it
were, in a depression of the chalk.
The depth of these strata varies
from one to five hundred feet.
MM. Brongniart and Cuvier di-
vided the strata into the five
following formations, commencing
with the undermost. 1. First
fresh- water formation ; consisting
of plastic clay, lignite, and first
sandstone. 2. First marine for-
mation ; comprising the calcaire
grossier. 3. Second fresh- water
formation ; containing silicious
limestone, gypsum, with bones of
animals, and fresh-water marls.
4. Second marine formation ; con-
sisting of gypseous marine marls,
upper marine sands and sandstones,
and upper marine marls and lime-
stones. 5. Third fresh- water for-
mation ; containing silicious mill-
stone with shells, and upper fresh
water marls. Subsequent obser-
vations have proved that this
division, as well as many of the
views entertained by MM. Brong-
niart and Cuvier, is not in accor-
dance with facts with which they
were unacquainted, and much
modification of the above arrange-
ment has been the consequence.
The silicious limestone, with fresh
water and terrestrial shells and
plants, and the calcaire grossier, or
first marine formation, often al-
ternate, and are deemed by M.
Constant. Prevost to be contempo-
raneous formations ; and it is not
improbable that while the wateri

P A E

[ 342]

PEA

in one lake or basin might be
marine, those in another might be
fresh, and thus two formations
containing different organic remains
might be deposited contempora-
neously. However the rocks of
this group may be eventually dis-
covered to differ from this type,
the labours of MM. Cuvier and
Brongniart on the rocks of the
Paris basin will not the less retain
that place in the annals of geology,
which by common consent has been
assigned them. Nor will the zoo-
logical discoveries of Cuvier, con-
stituting as they did such a
brilliant epoch in the history of
geological science, the less claim
the gratitude of geologists in suc-
ceeding ages.— De la Beche. Lyell.
Bakewell.

PA'ETICLES ELEME'NTAEY. The final
results of chemical analysis. Ele-
mentary particles are those of
which integrant particles are com-
posed ; thus, while the latter
remain invariable in the same
body, the former must vary with
the progress of chemistry. In
bodies really simple, the integrant
and elementary particles must be
the same. — Cleaveland.

PA'ETICLES I'NTEGEANT. These are
the smallest particles into which a
body can be reduced without de-
stroying its nature, or, in other
words, without decomposing it.
Only three forms of integrant
particles have hitherto been dis-
covered. They are the three most
simple, geometrical solids ; namely,
a tetraedron ; a triangular prism ;
and a parallelepiped, including" all
solids of six sides, parallel two and
two.

PAE'TICLES OF MATTEB. The indefi-
nitely small or ultimate atoms into
which matter is believed to be
divisible. Their form is unknown ;
but though too small to be visible,
they must have magnitude. — Mrs.
Somerville.

PA'ETITE. (partitus, Lat.) Divided,
In botany, a partite leaf is one
separated to the base.

PA'SSEEES. The third order of the
class Aves, or birds. The thrush,
warbler, sparrow, swallow, crow,
and lark, are comprised in this
order.

PATE'LLA. (patella, Lat. a little deep
dish with a broad brim.) That
bone of the leg commonly known
as the knee-pan.

PATE'LLA. In conchology, the limpet
shell. Animal a Umax. A marine
shell, univalve, subconic, shaped
like a basin ; without a spire.
The patella is found both recent
and fossil. Many species have
been found fossil in the neighbour-
hood of Paris. Patellae have also
been obtained from the Shanklin
sand, and from the Harwich cliffs.

PATE'LLIFOEM. (from patella, a dish,
and forma, form, Lat.) Of the
form of a small dish.

PATE'LLITE. A fossil patella.

PA'TULOTJS. fpatulus, from pateo, Lat.
to be open.) In botany, spreading,
as a patulous calyx. In conchology,
gaping ; with a spreading aperture.

PAVO'NIA. (from pavo, Lat. a pea-
cock.) "A genus of stony poly-
pifer, fixed and frondescent; the
lobes flat, subfoliaceous, erect or
ascending, with stelliferous rugge
or grooves on each side. The stars
lamellated, in rows, sessile, and
rather imperfect." — Parkinson.
There are several known species.
A coral with a deep and isolated
cell, such cell containing a large
depressed polypus, very similar to
the actinia, as regards both its
structure and appearance.

PEA OEE. | The Pisiform iron-ore

PEA IBON OEE. ) of Kirwan. Masses
of pea iron ore are found on the
sea beach near Scarborough. This
species of ore, which is met with
in Germany, Era-neb, Switzerland,
&c.} yields from thirty to forty per
cent, of iron. Its colour is bluish-

PEA

[ 343 ]

PEA

grey, and the grains or globules of
which the mass is composed, vary
from the size of mustard seed to
that of large peas.

PEA GEIT. A member of the inferior
oolite ; a pisolitic limestone, made
up of flattened oval concretions
rather larger than peas ; it occurs
near Cheltenham, and attains a
thickness of forty feet.

PEACH. A provincial term for either
chlorite or mica, if the latter have
a tinge of green.

PEAE E'NCEINITE. The Apiocrinites
rotundus, or Bradford encrinite. A
species of crino'idea abounding in
the oolitic limestone in the neigh-
bourhood of Bradford, near Bath.
When living, their roots were con-
fluent, and formed a thick pavement
over the bottom of the sea, from
which their stems and branches
rose into a thick submarine forest,
composed of these splendid zoo-
phytes. This bed of beautiful
remains has been buried by a thick
stratum of clay. The body of the
pear encrinite was of a pyriform
shape, from which circumstance it
has been thus named. The pear
encrinite is confined to the middle
oolite.

PEAEL. (perle, Germ . per k, Pr. ptrla,
It.) A spherical concretion con-
sisting of concentric coats of the
same substance as that which forms
the mother-of-pearl of the shell.
It is produced by the extravasation
of a lapidifying fluid, secreted in
the organs of the animal, the pearl
oyster, and filtered by its glands.
The animal that produces pearls in
the greatest abundance, of the
purest nature, and of the highest
value, has been formed by Lamarck
into a genus named Meleagrina;
Linne classed it with the muscles.
It inhabits the Persian gulf, the
coast of Ceylon, &c. It attains
perfection no where but in the
equatorial seas. The pearl fishery
off the island of Ceylon is the most

productive of any ; the oyster-beds
extending over a space thirty miles
long by twenty-four broad. The
oysters at the greatest depths yield
the largest pearls, which are situated
in the fleshy part, near the hinge.
For one pearl that is found per-
fectly round and detached between
the membranes of the mantle,
hundreds of irregular ones occur
attached to the mother-of-pearl;
these are sometimes in such numbers
as to prevent the animal from closing
its valves, and thereby cause its
destruction.

The pearl is supposed by some
writers to be the effect of disease ;
it is a formation forced upon the
oyster by some extraneous sub-
stance within the shell, which it
covers with mother-of-pearl. Sir
Everard Home considered that the
abortive eggs of the animal were
the nuclei upon which the pearls
were formed.

To collect the pearl oysters,
divers are employed; these men,
provided with baskets, descend to
the bed at the bottom of the sea,
and during their stay there, which
does not exceed two minutes, gener-
ally a minute and a- half, collect
into their baskets every thing they
can grasp, when they are rapidly,
at a signal given, hauled up to the
surface. When the bed is richly
stored, a diver will collect 150
oysters at one dip, and a single
diver will, in one day, bring up
from 1000 to 4000 oysters. — Kirby.

PEAEL SI'NTEE. Called also fiorite.
A variety of silicious sinter of a
white or grey colour, found in vol-
canic tuff.

PEA'ELSTONE. An igneous or volcanic
rock with a mother-of-pearl lustre.
The Perlstein of Werner ; Obsidi-
enne perlee of Brongniart; Lave
vitreuse perlee of Haiiy. Pearl-
stone is a variety of obsidian, occur-
ring in globular and concentric
lamellar, irridescent, translucent

PEA

[344]

PEC

concretions. It scratches glass.
Specific gravity from 2 '20 to 2-55.
"When breathed upon, it frequently
gives out an argillaceous odour.
Its constituents are silica 77*0,
alumina 13'0, lime and natron 2*6,
potash 1*4, oxides of manganese
and iron 2-0, water 4-0.

PEA STONE. A variety of limestone,
called also pisolite.

PEAT, (derived by some from the
German word pfutze, a pool, or
standing water.) An intermediate
substance between simple vegetable
matter and lignite, the conversion
of peat into lignite being gradual,
and brought about by the action of
water. This substance, arising
sometimes from the subversion of
forests covered by the sphagnum
palugtre, and other mosses, and
sometimes from the growth of
various maritime and semi-mari-
time plants on the marshes border-
ing the coasts, is found among the
most modern alluvia, generally
covering them; often containing
works of human art imbedded, and
in many instances still in the act of
progressive increase. Peat is com-
posed of the remains of many
different plants, but generally a
great portion is derived from the
Sphagnum palustre, and the pro-
cess by which these vegetables are
thus converted is clearly seen in
the sphagnum palustre. As the
lower extremity of the plant dies,
the upper sends forth fresh roots,
thus furnishing a perpetual supply
of decomposing vegetable matter.
Dr. Maculloch states, " where the
living plant is still in contact with
the peat, the roots of the rushes,
and ligneous vegetables, are found
vacillating between life and death,
in a spongy half decomposed mass.
Lower down, the pulverized car-
bonaceous matter is soon mixed
with similar fibres, still resisting
decomposition. These gradually
disappear, and at length a finely-

powdered substance alone is found,
the process being completed by the
total destruction of all the organised
bodies. The generation of peat,
when not completely under water,
is confined to moist situations,
where the temperature is low, and
where vegetables may decompose
without putrifying." While in the
upper portions of a peat bed we
may perceive the fibres of the vege-
tables, whence it has originated, in
an almost unchanged state ; in the
middle portions the texture presents
itself gradually obliterated, and the
mass is found passing into a com-
pact peat ; in the lowest part this
change is carried still farther, and
substances analogous to jet are met
with : in some instances beds of
peat alternate with beds of mud or
sand deposited in lakes, or of silt
and sand formed in the estuaries of
rivers ; in these cases they repre-
sent an imperfect and unmatured
coal formation.

Sir H. Davy states that one
hundred parts of dry peat contain
from sixty to ninety-nine parts of
matter destructible by fire. One-
tenth of the whole of the surface of
Ireland is stated to be peat. At
the bottom of peat-mosses there is
occasionally found a cake or pan of
oxide of iron ; whence this is de-
rived does not appear to be clearly
understood. The preservative pro-
perty of peat is very remarkable ;
bodies of persons who have perished
in peat-bogs have been kept free
from putrefaction for many years.

PECOP'TEBIS. A genus of fossil terres-
trial plants found in the coal mea-
sures.

PE'CTEN. (pecten, Lat. a comb.) A
genus of marine bivalves, belonging
to the family Ostracea. The pecten
is a fossil as well as a recent shell,
many species being found in our
seas. It is a regular, eared, longi-
tudinally ribbed, inequivalved bi-
valve, with contiguous beaks,

P E B

[345 ]

PEL

having a triangular auricle on each
side of the umbones. Hinge tooth-
less ; pit trigonal. One muscular
impression. Fossil pectens are
found in the neighbourhood of
Paris, and in many parts of Eng-
land ; in the Harwich cliff; in the
green-sand of "Wiltshire; near
Thame in Oxfordshire ; in Glouces-
tershire ; and in Sussex.

PEBBLE. j A roundish stone of

PEBBLE STONE. ) any kind from the
size of a small nut to that of a
man's head. A general term for
water-worn minerals. A mineral
distinguished from a flint by its
variety of colours.

PE'CTINATE. | (from pecten, a comb,

PE'CTINATED. j Lat.)

1. In conchology, resembling a
comb ; cut into regular, straight
segments like a comb.

2. In botany, applied to a pinna-
tifid leaf, whose segments are
extremely narrow, resembling the
teeth of a comb.

PECTINIBRANCHIA'TA. The sixth or-
der of mollusca, in Cuvier's arrange-
ment.

PE'CTOLTTE. A mineral, a silicate of
lime and soda.

PECTTJ'NCULITS. A genus of orbicular
sub-equilateral marine bivalves,
with an arched hinge ; numerous
teeth, alternately inserted in a
single row; of the family Arcadidoa.
Pectunculi are easily recognized by
their rounded or lenticular form.
Muscular impressions two, and
strongly marked. Recent pectun-
culi are found at depths varying
from five to seventeen fathoms, in
sandy mud and sands. Fossil pec-
tunculi are met with in the London
clay and calcaire grossier, and in
the Bognor sandstone.

PE'DATE. (pedatm, Lat. frompes, a
foot.) In botany, applied to leaves
in which a bifid petiole connects
several leaflets on the inside only ;
also to a peculiar kind of ternate
leaf, its lateral leaflet being com-

pounded in the fore part : the black
hellebore is an example.

PE'DICEL. In botany, a partial flow-
er-stalk, or a subdivision of the
general one, each subdivision being
termed a pedicel.

PEDIPA'LPI. The second family of
Arachnidans. They have very
large palpi terminated by a forceps
or claw. The principal animals
among the pedipalps are the scor-
pions, possessing powerful organs
for seizing their prey, and having
a tail terminating in a deadly sting.
The other pedipalps are not armed
with a sting.

PE'DUM. (pedum, Lat. a shepherd's
crook.) A genus of marine bival-
vular shells, found attached by a
byssus to rocks. It is an eared
inequivalved bivalve, gaping at the
lower valve, and having its beaks
separated : hinge toothless ; liga-
ment exterior; inferior notch
grooved.

PE'DUNCLE. (pedunculus, Lat. from
pedo, a splay foot.)

1. In botany, the stalk that bears
the flower and fruit.

2. In conchology, a sort of stem
by which the shells of the second
division of lepas are attached to
wood, &c.

PEDTJ'NCULATE. } Attached to objects

PEDlfNCULATED. ) SUCh as WOod,

rocks, &c., by a peduncle; having
a peduncle.

PE'GMATITE. A name given by the
French mineralogists to a variety
of granite composed of granular
quartz and felspar. When in
granite, the mica disappears, and
only quartz and feldspar are left,
we have Pegmatite, or Graphic
Granite.

PELA'GIAN. ) (pelagus, Lat. the sea.)

PELA'GIC. j Belonging to the sea.
Lyell says, "belonging to the deep
sea."

PELA'GIAN FOBMATIONS. Oceanic accu-
mulations ; deposits by currents, or

T T

PEL

L 346 3

PEN

from other causes, at the bottom of
the sea.

PEL'DON. "We can sometimes trace
sandstone becoming finer and finer,
till we arrive at a rock for which
•we have no very accurate or dis-
tinctive name, — a flinty or silicious
rock, with a perfectly smooth com-
pact texture, a conchoidal fracture,
without anything we could call a
grain. A rock of this kind, when
. met with in the coal-measure of
S. Staffordshire, is there called a
peldon, and I venture to propose
that designation for the acceptance
of my brother geologists. — 'Jukes.
PE'LIOM. (from ire\itofiMt Gr. blue-
ness, or of a lead colour.) A blue
coloured mineral resembling iolite,
of which it is a variety. It is
found in Bavaria.

PE'LLICLE. (from pellicula, Lat.) A
film ; a thin crust or covering.

In botany, a membranous or
mucilaginous covering, closely ad-
hering to the outside of some seeds,
so as to conceal their proper surface
and colour.

PELTA'TE. (from pelta, Lat. a target.)

In botany, a term applied to leaves

which have their footstalk inserted

in the middle of the leaf, and not

joined to the edge ; the nasturtion

is a familiar example.

PE'LVIS. (pelvis, Lat. from we'Xvs,

Gr. a basin.) The lower part of

the trunk of vertebrated animals.

PE'NCIL. A name given to the belem-

nite.

PE'NNATE. j (pennatus, Lat. from pen-
PE'NNATED. j nat awing.) Winged;

feathered.

PENNA'TITLA. Called, commonly, the
Seapen. A polypus with a calca-
reous axis or stem, having a double
set of branches extending in the
same plane from both sides, like
the vane of a quill. Pennatula3 are
not fixed by any attachment to
the ground, but float about in the
waters of the ocean, carried hither

and thither as the current may
direct them.

PE'NNIFORM. (from penna, a feather,
and. form.) Having the form of a
feather or quill. In anatomy,
muscles in which the muscular
fibres pass obliquely outwards on
either side from a tendinous centre,
are termed penniform. The rectus
femoris affords an illustration of a
penniform muscle.

PENTACA'PSULAE. (from TreVre, Gr.
five, and capsular, Lat. a cell or
capsule.) Having five cavities,
capsules, or cells.

PENTA'CEROS EETICTJLA'TTJS. A fossil
species of asteria, or stella marina.

PENTA'CEROS DENTIGINO'SUS. A fossil
species of asteria or stella marina,
found in the chalk and in the Lon-
don clay.

PENTACRI'NEA. A tribe of stone-lilies,
comprising the living genus Penta-
crinus (including Chladocrinus and
Extracrinus) and the extinct genus
Isocrinus.

PENTA'CRINITE. The fossil Pentacrinus.

PENTACRI'NTJS. (from TreWe, five, and
encrinite.) The five angled lily-
shaped animal. A genus of the
family Crino'idea. Miller thus de-
scribes the generic character of
pentacrinus. " An animal with a
column formed of numerous pent-
angular joints, articulating by sur-
faces with pentapetalous semi-
striated markings. Superior colum-
nar joint supporting a pelvis of
five joints, on which five first
costals rest, succeeded by five
second costals and five scapula,
from which ten arms proceed,
having each two hands, composed
of several tentaculated fingers.
Column long, having numerous
auxiliary side arms. Base unas-
certained." The arms, when ex-
panded, resemble a star of five (or
six) rays ; and when they converge,
a pentapelous or hexapetalous flow-
er. The whole animal, when alive,
is supposed to be invested with a

PEN

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PEN

gelatinous muscular integument.
From the circumstance of penta-
crinites abounding in the lias and
lower strata of the oolite, and dis-
appearing entirely in the upper-
most strata, geologists were dis-
posed to limit their existence to
certain periods, and to conclude
that the pentacrinite furnished the
remains of an extinct genus. Sub-
sequent discoveries, however, prove
that the pentacrinus does still exist,
and thus, probably, it may be with
many genera which, in ignorance,
geologists describe to be extinct,
merely because they have not met
with living or recent specimens.
The calcareous joints which com-
pose the fingers of the Pentacrinus
Europaeus, are capable of expansion
and contraction in all directions ;
now spreading outwards, like the
petals of an expanded flower, and
again rolled inwards towards the
mouth in the form of a closed bud.
These organs serve to seize, and
convey to the mouth, the food of
the animal. The number of bones
in each animal is computed at thirty
thousand. Dr. Buckland says that
the number of bones in the Briarean
Pentacrinite exceeded a hundred
and fifty thousand. The number
of bones in the fingers and tenta-
cula amount at least to a hundred
thousand, and fifty thousand more,
(which is considerably under the
real number), may be added for the
ossicula of the side arms. Each
bone requiring at least two fasciculi
of fibres, one for expansion, the
other for contraction, the Briarean
Pentacrinus must have had three
hundred thousand fasciculi of fibres
equivalent to muscles.

" The pentacrinites differ consid-
erably," says Mantell, "in their
form and structure from the encri-
nites, the name of encrinite being
given to the species in which the
bones of the column are circular or
elliptical, that of pentacrinite to

those which have an angular er
pentagonal stem. The lias of Lyme
Regis abounds in the remains of
these animals; and large slabs often
have the whole surface covered
with the plumose tentacula of pen-
tacrinites, converted into pyrites."
" There are instances," says
Miller, "of the column of this
genus having sometimes a tetra-
gonal, or hexagonal form, these I
consider as monstrous varieties."

PENTADA'CTYL. (from TreWe, five, and
£a/cTt/\o9, a finger, Gr.) Having
five fingers. Applied also to leaves.

PE'NTAGON. (from TreWe, five, and
7oWa, an angle, Gr.) A figure
having five sides and five angles.

PENTA'GONAL. Having five angles
and five sides ; quinquangular.

PENTAGONA'STEE SE'MILUNATUS. A fos-
sil species of the stella marina.

PENTAGOSTA'STEE EEGULA'EIS. A fossil
asterite, or species of the stella
marina.

PE'NTAGYN. (from TreVre, five, and
yvvYj, a woman, Gr.) A plant
which has five pistils.

PENTAHE'DEAL. Having five equal
sides.

PENT IHE'D EON. (from TreW, five,
and edpa, a base, Gr.) A figure of
five equal sides.

PENTA'MERTJS LIM'ESTONE. The name
assigned to a rock of the Helderberg
group. The Upper Pentamerus
beds, or May Hill sandstone, or
Upper Llandovery beds, attain a
thickness of 1000 feet, being a
formation of the Upper Silurian
period.

PENTA'MERUS. A genus of fossil Bra-
chiopodous shells, described as
equilateral, inequivalve, one valve
being divided by a central septum
into two parts, the other by two
septa into three parts; the umbones-
are incurved and imperforate ; five
species of Pentamerus are found in
the Silurian system of rocks in
England and "Wales. — Lycett.

PENTA'NDEE. (from TreVre, five, and

PEE

[ 348 ]

PER

avY]py a man, Gr.) A plant having
live stamens.

PENTA'NDEIAN. Having five stamens.

PENTAPHYLLOI'DAL. (from vevre, five,
<frv\\ov, a leaf, and e?e>os, resem-
blance, Gr.) Appearing to have
five leaves ; resembling five leaves.
The Placentae are all ornamented
with a pentaphylloidal flower.

PENTELA'SMIS. (from TreVre, five, and
eXafffia, a plate, or layer, GF.) A
species of Anatifa, or of the Lepas
of Linnaeus.

PE'NTEEMITES. An extinct genus of
fossil encrinites, established by
Say, of the order Blastoidea.

PEPEBI'NO. The name given by
Italian geologists to a particular
form of volcanic tuff, composed of
basaltic scoria.

PEEA'MELES. A genus of marsupiala.
The following description is from
Col. Mitchell's Australia. " The
most remarkable incident of this
day's journey was the discovery of
an animal, of which I had seen
only the head amongst the fossil
specimens of Wellington valley.
This animal was of the size of a
wild young rabbit, and of nearly
the same colour, having a broad
head, terminating in a long and very
slender snout, like the narrow neck
of a wide bottle ; and no tail. The
feet, and especially the fore legs,
were singularly formed, the latter
resembling those of a hog, and the
marsupial opening was down-
wards, and not upwards, as in the
kangaroo and others of that class
of animals."

PEEE'NNIAL. fperennis, Lat. perenne,
It.) In botany, applied to plants
that live many years, bearing
flowers and fruit frequently.

PEEFO'LIATE. In botany, applied to
leaves when the stem appears to
pass through their substance. The
common hare's-ear is an example.

PE'RIANTH. (from Trepl, about, and
tti/009, a flower, Gr.) The calyx is
BO called when it is united with

the corolla, so as to form only one
floral envelope.

PEEICA'EDITJM. (from Trepl, round,
and Kap&a, the heart, Gr.pericarde,
Pr. pericardia, It.) The membrane
which envelopes the heart.

PE'EICAEP. (from Trepl, round, and
KapTros, fruit, Gr. pericarpe, Fr.)
The ovarium, when ripened into
fruit, is called the pericarp; this
consists of three parts, which in
some fruits, as the peach and plum,
are easily separable. The outer
skin is called epicarp ; the fleshy
part, the sarocarp; the stone, or
shell, the endocarp. There are ten
different kinds of pericarps, namely,
drupe, pome, berry, follicle, silique,
silicle, legume, capsule, nut, and
strobile.

PE'EICHLIN. A feldspathic mineral,
an albite, in which part of the soda
has been replaced by potash.

PEKICLI'NITJM. The name given by
foreign botanists to a kind of
involucre.

PE'EIDOT. The name given by Haiiy
to prismatic chrysolite.

PEEIGE'E. (from Trepl, round, and <y§,
the earth, Gr. perigee, Fr.) A
term used to denote that point
where the sun is nearest to the
earth. The perigee of the lunar
orbit is the point where the moon is
nearest to the earth.

PEBI'GYNOUS. (from Trepl, about, and
ryvvjj, a woman, Gr.) Inserted
around the pistil. When the
stamens grow out of the corolla,
calyx, or perianth, or are not in any
way joined to the seed-vessel, they
are said to be perigynous.

PEEIHE'LION. The point of an orbit
nearest to the sun.

PEEISSODA'CTYLA. Odd-toed ; having
one or three toes. This order of
mammalia is divided into two
families, namely, Solipedia, com-
prising the horse, and Pachyder-
mata.

PEEIO'STEUM. (from Trepl, around,
and eoTsov, a bone, Gr. perioste, Fr.)

OTA

[349]

0 X Y

The membrane which covers the
bones ; that, however, which covers
the bones of the skull is called
the pericranium.

PEHIPHOKA/NTHITTM. When bracts are
collected into a whorl, as in um-
belliferous plants, they are said to
form an involucre, which, if very
small, receives the diminutive
name of involucel. This kind of
organ is very remarkable in com-
pound-flowered plants, appearing
as if it constituted a calyx common
to many flowers ; and hence it
used to be called a common calyx.
It, however, does not differ from
the involucre in any thing more
than its bracts being more nu-
merous, more closely packed, and
parallel with each other, instead
of diverging. Foreign botanists
have given the names Periphoran-
ihium and Peticlinium to this kind
of involucre.

PER'MEABLE. fpermeo, Lat. from
per through, and meo to pass or
glide ; permeable, Fr.) That may
be passed through without rupture
or displacement of its parts. Ap-
plied to substances that admit the
passage of fluids. All permeable
strata receive rain-water at their
surface, whence it descends until
it is arrested by an impermeable
subjacent bed of clay, causing it to
accumulate, and to form extensive
reservoirs, the overflowing of which
on the sides of valleys constitute
the ordinary supply of springs and
rivers.

PER'MIAN. The newest of the primary
or palaeozoic formations, consisting
of the following deposits in ascend-
ing order. 1. Red sandstone and
marl. 2. Conglomerates and brec-
cia. 3. Lower red sandstone and
marl. 4. Magnesian limestone.
The term Permian is derived from
the district of Perm in Russia,
where the formation in question
is very extensively developed. —
Lycett.

PE'RNA. A genus established by
Bruguie*res. A flat, irregular, sub-
equi valve, compressed, foliaceous,
marine, bivalve. Several parallel
cavities across the hinge opposed
to each other in the two valves,
and lodging as many elastic liga-
ments : anterior margin with a
passage for a byssus. Recent and
fossil.

PE'EOXIDB. When oxygen is com-
bined with any substance, in the
highest proportion it is capable of,
whatever that may be, it is called
a peroxide.

PERSI'STENT. (from persisto, Lat. to
abide.) In botany, opposed to
deciduous. Not withering and
falling; remaining. 2. Unbroken;
continuing. In almost every for-
mation the individual strata are
rarely persistent for a great distance.

PE'RSONATE. A term applied to a
monopetalous flower of an irregular
form, the border of the corolla
having an oral appearance with
the labia closed.

PE'TAL. (TreVaXoi/, Gr. p&tale, Fr.)
The name given to each leaf of the
corolla, or flower of a plant.

PE'TALITE. (from Treraw and .\t0os,
Gr.) A mineral, of a reddish, or
greyish-white colour, which has
only been found in Sweden. It
consists of silica 7 7*0, alumina 17fO,
lithia 6*0 ; or according to others,
of silica 76-21, alumina 17'22,
lithia 5*76. It occurs in a mine of
black iron ore, associated with
spodumene, felspar, tourmaline,
mica, and quartz. Its fracture is
foliated; scratches glass; brittle,
and translucent at the edges.
Specific gravity 2-62.

PETALO'IDE^E. In botany, the second
order of the class Endogens, com-
prising the banana, orchis, palms,
lilies, &c.

PE'TIOLE. (from petiolus, Lat. the
stalk of fruits.) In botany, a foot
stalk; the stalk, or stem, whiclj
connects the leaf with the branch.

PET

[ 350 ]

PET

PETE'AIA. A genus of fossils found
in the Silurian formation, of which
many species have been described.

PETRI'COLA. (from TTGT/JO?, a stone,
Gr. and colo, to inhabit, Lat.) A
genus of transverse, inequilateral,
bivalve, marine shells, belonging
to the family Lithophagi. Two
muscular impressions ; two hinge-
teeth on one valve, and a bifid one
on the other ; anterior side rounded,
posterior side more or less slightly
gaping ; ligament external. Petri-
colse are found at depths varying
to ten fathoms ; they inhabit cavi-
ties, of their own working, in rocks
and shells. They may be distin-
guished from saxicava by the regu-
larity of their form, and by the
teeth on the hinge, which in saxi-
cava become obsolete when the
animal is full grown.

PETEIFA'CTION. (petrifaction, Fr.)

1 . A substance converted into stone.
Substances, either animal or vege-
table, converted into stone by the
infiltration, or incrustation, of sili-
cious matter.

2. That process by which organic
remains are mineralized, and their
external form, and more or less of
their internal structure, preserved.

PETEE'SCENT. (from petrescens, Lat.)
Becoming stone; growing into stony
matter.

PE'TEIFIED KAIL. A local name given
to a bone of the Asterolepis, a gi-
gantic ganoid of the old red sand-
stone. This nail-like bone formed
a characteristic portion of the As-
terolepis.— Hugh Miller.

PETRO'LEUM. (petr6le,'Fr.) A mineral
oil, rather thicker than tar, and of
a reddish-brown colour ; it has
obtained its name from the circum-
stance of its oozing out of rocks
like oil. In the East it is burnt as
oil. It is unctuous to the touch,
and exhales a strong and unpleasant
odour. It is lighter than water,
its specific gravity being 0'87. In
the island of Zante, petroleum is at

the present time obtained from the
same spot, and in the same manner,
as in the days of Herodotus. The
most powerful springs producing
petroleum are on the Irawaddi, in
the Burman empire. In one lo-
cality there are said to be 520
wells, yielding annually 400,000
hogsheads of petroleum. It occurs
in most countries where coal is
found.

In describing the coal-field of
Coal Brook Dale, Sir R. Murchison
says, "Petroleum is of constant
occurrence in the upper as well as
lower measures; the chief source
of this mineral at Coal Port, which
formerly afforded one hogshead a-
day, being in a thick-bedded sand-
stone of the upper measures. This
supply has, however, much de-
creased with the opening of new
coal works. Other wells have
been discovered in the lower coals
at Prior's Lee. In some pits, the
petroleum exudes in such quantities
that the works are necessarily
boarded up to prevent its infiltra-
tion upon the workmen."

PETEO'LOGF. The study of rock
masses ; or the examination of
those characters, structures, and
accidents of rocks which can only
be studied on the large scale, and
only be observed in the field. —
Jukes.

PETEO-PHILOIDES. The name assigned
by Mr. Bowerbank to a genus of
fossil fruits found in the London
clay : he thus describes the generic
characters. "Fruit, a strobilus.
Squamae usually confluent, rarely
separate. Seed bilobate, without
a comose or foliaceous appendage."
Mr. Bowerbank describes seven
species, and in speaking of the
genus he says, alluding to their
approximation to Petrophila, "I
have thought it better to call them
Petro-philoides, rather than desig-
nate them by any other name
which would not serve as an indi-

PET

[351 ]

P H 0

cation of their nearest affinity with
genera existing at the present
period."

PETROSI'LEX. A fusible variety of
hornstone ; according to some au-
thors, the same as clinkstone; to
others, compact felspar.
PETTJ'NSE. | The felspathe petuntze
PETU'NTZE. > of Brongniart. A
PETU'NZE. ) variety of felspar, used
in the manufacture of porcelain.
It is called Petuntze by the Chinese.
PE'T WORTH MA'RBLE. Called also Sus-
sex marble, occurs in layers varying
from a few inches to a foot and
upwards in thickness, separated
from each other by seams of clay.
The Petworth or Sussex marble is
a limestone of various shades of
colour, occurring in the Weald
clay; it is composed of the remains
of fresh-water univalves, shells of
the paludina, and crusts of the
cypris faba, united into a compact
marble by a gangue of calcareous
cement. The more compact varie-
ties bear a beautiful polish, and are
elegantly marked, when cut into
slabs, by the section of the con-
tained shells.

PHA'COPS. A genus of fossils found
in the Silurian rocks, of which
there are many species.
PHANEROGA'MIC. ) (from (fravepos,
PHANEROGA'MOUS. j manifest, and
fya/«>?, marriage, Gr.) Plants in
which the stamens and ovarium are
distinctly visible ; plants having
the reproductive organs visible.
In all the phanerogamous plants, the
whole of the double apparatus re-
quired for reproduction is contained
in the flower. The term is used
in contra- distinction to crypto-
yamous.
PHARMA'COLITE. The name given by

Brochant to arseniate of lime.

PHASCOLOTHE'RE. | An extinct genus

PHACOLOTHE'RIUM. ) of entomopha-

gous marsupials, discovered in the

Stonesfield slate. I am indebted to

my friend, Mr. Lycett, of Minchin-

hampton, for the following obser-
vations : — In remarking upon the
little Marsupial Mammal Phascolo-
theriumBucldandi, portions of which
have occurred in the great oolite of
Stonesfield, Oxon, Hugh Miller
speculates upon the possibility of
there having existed along with
them extinct species of Thylacinas
and Dasyurus, (two recent genera
of Australian carnivorous Marsu-
pials) being led to such a train of
thought by the analogy which the
fauna and flora of recent Australia
presents to those of the ancient oolitic
formations, but no fossil Thylacin us
or Dasyurus has been found in
Britain. Bones of extinct species
of Dasyurus, Macropus, Phasco-
lomys, Phalangista, Diprotodon,
(N. G. Owen) and Hypsiprymnus
were collected in the bone caves of
Wellington Yalley, Australia, by
the late Sir Thomas Mitchell.

PHASIANE'LLA. (from phasianus, Lat.
a pheasant.) A genus of shells
belonging to the family Trochoida ;
or, according to Lamarck's arrange-
ment, Turbinacea. It is a solid
ovate or conical univalve ; opening
longitudinal, ovate, and entire ; lip
thin ; columella smooth, with an
attenuated base. Recent phasia-
nellae are inhabitants of the Indian
ocean ; they are found on the coasts
and in estuaries, at small depths
only.

PHI'LLIPSITE. A mineral, found ac-
companying Herschelite. It is a
species of Harmotome or cross-
stone, containing lime and potash
instead of baryta.

PHO'LAS. (0w\as, from <j)w\etD, Gr.
to lie concealed.) A genus of
marine bivalves, belonging to the
family Inclusa ; or, according to
Lamarck's arrangement, the family
Pholadaria. A transverse gaping
shell, composed of two principal
valves, with several small accessory
pieces placed on the ligament, or at
the hinge. A long curved tooth

P H 0

[352]

PHY

protrudes in each valve from beneath,
the umbones. Pholades are found
at depths varying to nine fathoms ;
they pierce wood, rocks, indurated
clay, &c. They are much sought
for in consequence of their delicious
flavour.

PHO'LADITE. A fossil or petrified
pholas.

PHO'NOLITE. (from 0oj^, sound, and
X/00S, a stone, Gr.) Another name
for clinkstone. A felspathic rock,
sonorous when struck with a ham-
mer, from which circumstance it
derives its name.

PHO'SPHATE. A salt formed by the
union of phosphoric acid with a
salifiable base.

PHO'SPHATE OF LIME. This is found
in the bones of animals, and consti-
tutes their base ; as well as in the
mineral kingdom. It consists of
lime 59*0, phosphoric acid 41'0.
It is destitute of taste, insoluble in
water, and not affected by exposure
to the atmosphere. Exposed to
a very high temperature it becomes
soft, and is converted into a white
semitransparent enamel, or rather
porcelain. Human bones, accord-
ing to Berzelius, contain 51*04 of
phosphate of lime, and the enamel
of teeth, according to Mr. Pepys,
is composed of 78 per cent, of it.
Sulphuric, nitric, muriatic, fluoric,
and several vegetable acids are
capable of more or less decomposing
phosphate of lime.

PHOSPHORESCENCE or THE SEA. This
luminous appearance of sea-water
arises from the presence of immense
numbers of microscopic niedusaB
which people every region of the
ocean, and, being specifically lighter
than the sea-water, float in incal-
culable multitudes on its surface.

PHOSPHORE' SCENT. Emitting light in
the dark without sensible heat.

PHO'SPHORITE. Amorphous phospate
of lime. The chaux phosphate e
terreuse of Haiiy; phosphorit of
Werner ; phosphorite of Jame-

son. A variety of apatite,
with commonly an earthy aspect :
it occurs in masses whose surface
often displays mammillary projec-
tions. Fracture dull and earthy.
Colour white or grey, often marked
with spots or zones of a brownish
tinge. Specific gravity from 2-8
to 3-2. Before the blow-pipe it is
infusible, but its powder thrown
upon live coals emits a yellowish-
green phosphorescent light. In
Spain it forms whole mountains;
it is also met with in Germany.
According to Pelletier, it contains
lime 59, phosphoric acid 34, and
the remainder consists of the car-
bonic, fluoric, and muriatic acids,
with a trifling portion of silex and
oxide of iron.

PHO'SPHORTJS. (0wo-0o/9V9, Gr. phos-
phorus, Lat. phospkore, Fr.) One
of the simple or elementary sub-
stances, and belonging to that sub-
division termed non-metallic. Phos-
phorus is principally known as
entering into the chemical com-
position of animals. As a com-
ponent part of minerals, phosphorus
is rare; but there must be some
amount of it entombed in fossili-
ferous rocks. Phosphorus is never
found pure in nature, and is only
to be obtained from organic matter
by elaborate chemical processes. It
is yellow, and semi-transparent;
resembling wax in softness, but
more cohesive and ductile. Specific
gravity 1*77. Its affinity for oxy-
gen is so great that it burns spon-
taneously in the atmosphere. It
should always be kept in bottles
filled with water, and well corked.

PHOTO'METER. (from 0£>s, gen, 0u>ros,
and fierpov, measure, Gr.) An
instrument for measuring the in-
tensity of light.

PHYLLA'DE. The name given by
D'Aubuisson, and the French geol-
ogists, to clay-slate. Under the
name of Phyllade, Dr. Boase in-
cludes a genus of rocks comprising

PHY

[ 353 J

P I

four species. Phyllade is largely
found in Cornwall and Devon. The
rocks comprised in this genus con-
sist in great measure of very thick
beds, which are closely lamellar,
and even compact and jointed, like
the felspar rocks ; indeed, they
seem to be principally composed of
felspar, the most compact and sili-
cious becoming weathered on ex-
posure to the atmosphere. Phyllade
differs from corneanite in having a
granular instead of a compact basis,
and it always contains minute
spangles, like scales of mica.

PHY'SALITE. A variety of prismatic
topaz, of a greenish-white colour.
It occurs in coarse granular con-
cretions, having a low degree of
lustre. Edges feebly translucent.
It consists of alumina 57*75, silica
34-30, fluoric acid 7'81.

PHY'LLITE. (from 0vX\oj/, a leaf, and
7u'0os, a stone, Gr.) A petrified
leaf.

PHYLLO'PHAGOTTS. An animal that
feeds on leaves ; the silk-worm is
an example.

PHYLLOLE'PIS. The name assigned
to a genus of ichthyolites of the
old red sandstone.

PHY'SICAL. (physique, Fr. fisico, It.)
Relating to nature or to natural
philosophy ; not moral ; pertaining
to material things.

PHY'SICS. (from 0tW, nature, Gr.)
Taken in its most enlarged sense,
comprehends the whole study of
nature ; but in the usual accepta-
tion of the word, that branch of
science which treats of the proper-
ties of natural bodies, and includes
natural history and philosophy.

PHYTI'VOEOUS. (from 0vroi/, Gr. a
plant, and voro, Lat. to devour.)
Feeding on plants.

PHY'TOLITE. (from 0tn-oj/, a plant,
and X/005, a stone, Gr.) A petri-
fied or fossilized plant.

PHYTO'LOGY. (from 0vroi/, a plant,
and Xo'ryos, discourse, Gr.) That
department of science which treats

of the nature, habits, qualities, &c.,
of plants.

PHYTO'PHAGOUS. (from 0m-oi/, a plant,
and 0a<yetV, to eat, Gr.) Feeding
on plants; devouring plants ; feed-
ing on vegetable substances.

PHYTOSAT/RUS. A fossil saurian dis-
covered in the saliferous formation,
and thus named by Jaeger.

PHYTOZO'A. (from 0vroi/, a plant,
and %wov, an animal, Gr.) Plant-
like animals. Another, and more
modern, as well as appropriate
name for zoophytes.

PI'CROSMLNE. A silicate of magnesia,
having nearly the same composition
as serpentine.

PIGME'NTTTM NI'GRUM. A dark brown,
or nearly black substance, which
covers the surfaces of the choroid
membrane of the eye, and gives to
it its colour.

PI'LETJS. The name given to a genus
of fossil echini ; pileus is another
name for conulus.

PI'LLAR. In conchology, the colum-
ella, or perpendicular centre,
which extends from the base to
the apex, in most of the spiral
shells.

PI'LLAR- LIP. In conchology, a conti-
nuation of the glossy process with
which the aperture of shells is
lined, expanded on the columella.

PI/LOSE, (pilosus, Lat.) In entomo-
logy, covered with dispersed, long,
and bent hairs.

PI'MELITE. A variety of steatite,
coloured by chrome or nickel.

PI'NEAL GLAND, (frompineus, Lat. a
pine.) The name given to a gland
of the brain from its supposed re-
semblance to a pine. This gland
was at one time supposed to be the
seat of the soul.

PI'NNA. (pinna, Lat. the fin of a
fish.) A genus of marine bivalves,
belonging to the family Mytilacea.
A cuneiform, longitudinal bivalve,
with an acute base, the upper part
gaping; hinge without a tooth,
lateral, and very long ; valves co-
z z

I N

[ 354 J

P I

alescent. Recent pinna? are found
in the ocean at depths varying to
seventeen fathoms; they are moored
by a long silky byssus, which has
been manufactured into stockings
and gloves. Pinnse have been found
fossil in the limestone of Gloucester-
shire, "Wiltshire, and Somersetshire.

PI'NNTGRADA. A division of the order
Oarnivora, of which the Seal and
Morse are examples.

PI'NITE. A silicate having one equi-
valent of silicate of potash, or pro-
toxide of iron, to one of bisilicate
of alumina, and also containing
water. Sp. gr. 2'8. Slightly
translucent ; colourless before the
blowpipe, and fuses at the edges to
blistered glass.

PI'NNITE. A fossil pinna.

PI'NNATE. \fpinnatus, Lat. winged.)

PI'NNATED. ) In botany, applied to
compound leaves, composed of many
leaflets, placed on each side of the
petiole ; these are placed in pairs
opposite to each other, and in some
cases, an odd leaflet at the termina-
tion, or, in others, a tendril: of
the former the rose furnishes an
example ; of the latter, the vetch.

PINNA'TIFID. In botany, applied to
leaves cut transversely into several
deep, oblong, parallel segments,
the incisions reaching nearly to the
midrib, and dividing the leaf into
irregular forms, termed lobes. The
groundsel affords a familiar illus-
tration.

PIPE-CLAY. The Pfeifenthon of Wer-
ner. This is the purest kind of
potter's clay, and is called pipe-
clay, from its being manufactured
into tobacco pipes. It is of a grey
or greyish white colour ; is infusi-
ble ; and on exposure to a strong
heat becomes white. It is abun-
dant in Devonshire and Stafford-
shire; a stratum, in a horizontal
position above the chalk, extends
from Headfast Point to beyond
Corfe Castle in Dorsetshire. It

forms the basis of the Queen's
ware pottery.

PISCI'VOROTJS. (from piscis, a fish,
and voro, to devour, Lat.) Feeding
on fishes ; devouring fishes ; sub-
sisting on fishes.

PI'SIFORM. (frompisum, a pea, and
forma, form, Lat.) Of the form of
a pea ; having a structure resem-
bling peas.

PI'SIFORM IRON ORE. j The pea ore

PISIFORM IRON STONE. ) of Jame-

son ; pisiform iron stone of Kirwan.
A variety of argillaceous oxide of
iron, occurring in small masses or
grains, nearly or quite spherical,
and often equal in size to a pea, or
even larger. These globules are
composed of thin, concentric layers,
which decrease in density as they
approach the centre. The exterior
layers are compact, and present an
even, glistening fracture with a
resinous lustre, whereas the centre
of the grain is almost always
friable, and has a dull earthy
fracture. They are easily broken,
and may be cut by a knife. Spe-
cific gravity 3.40. These grains,
sometimes solitary, are generally
united by a ferruginous cement,
either calcareous or argillaceous,
which adheres to their surface.
This variety is composed of oxide
of iron 71'5, water 14-5, silex 7'5,
alumine 3*5, oxide of manganese
0*5. It is abundant in France,
Switzerland, and Germany : oc-
curring in secondary rocks.
PI'SOLITE. (from TTIOOV, a pea, and
X/009, a stone.) So called from its
resembling an agglutination of
pease. The pisolithe of Brongniart ;
the peastone of Jameson. Pisolite
is nearly or quite opaque, and
consists of small rounded masses,
composed of concentric layers, each
concretion having a grain of sand
for its nucleus, or centre. These
concretions, agglutinated by a cal-
careous cement, form masses of

PIS

[ 355 J

considerable magnitude, and some-
times continuous beds.

PISOLI'TIC. Composed of pisolite ;
containing pisolite ; resembling pi-
solite.

PI'STACITE. | Another name for epi-

PI'STAZITE. } dote.

PI'STIL. (from pistillum, Lat. pistil,
Fr.) In botany, the female organ
of the plant ; situated in the centre
of the flower, and forming the
rudiments of the fruit. A perfect
pistil is composed of three parts,
the ovarium, the style, and the
stigma. Each modified leaf which
forms the pistil, is called a car-
pellum : the carpella are so folded
that the margins of the leaf are
next to the axis, or centre; and
from these a species of bud is pro-
duced, which is the seed. The
form of the pistil must depend on
that of the carpella, on their
number, and on their arrangement.

PITCH-STONE. A vitreous lava, of a
blackish-green, or a nearly black
colour; a semi- vitreous substance
having the lustre and appearance
of pitch, and containing a portion
of bitumen. Specific gravity from
2-29 to 2-64. Before the blow-
pipe it whitens, tumesces, and
fuses into a porous, whitish enamel.
It consists of silex 73, alumine
14-5, soda T75, lime 1, oxides of
iron and manganese !•!, water
8'50. Pitch-stone occurs in veins
and in beds, sometimes forming
whole mountains.

PIT COAL. The coal usually con-
sumed in our houses, and thus
called from its being dug out of
pits.

PLACE'NTA. (placenta, Lat. a cake,
placenta, Fr.)

1. In anatomy, the medium of
communication between the mother
and the foetus.

2. In botany, that part of the
ovarium to which the seeds are
attached.

3. In fossilogy, the name given by

Klein to a section of catocysti,
from the shells being flat, like a
cake. They are all ornamented
with a pentaphylloid flower. The
mouth is in the middle of the base,
and the anal orifice near the
margin. Placenta are divided
by Klein into three genera, mellita,
laganum, and rotula.

PL'ACENTALIA. (from placenta, a cake,
Lat.) The name given to one of
the two great sections into which
the class mammalia is divided.
The orders comprised in this
section have been thus named from
a predominating feature in the re-
productive system of the animals
comprehended in them. Feetus
ad uterum maternum annexus per
medium placentas vera3, diverse*
conformatae, diversis mammalibus j
vel, inloco illius, membrana villosa,
et vasculari, x^/j/oi/ dicta. — Martin.

PLACOI'DEA. (from 7r\ag, a broad
plate, and eloo-s, form, Gr.) One
of the orders into which M. Agas-
siz divides the class of fishes. The
placoidians are distinguished by
their skin being irregularly co-
vered with plates of enamel. In
this order are comprised all the
cartilaginous fishes of Cuvier, the
sturgeon only excepted.

PLACOTHO'EAX. A genus of ichthyo-
lites of the old red sandstone.

PLAGIA'ULAX. (an abbreviation for Pla-
giaulacodon, from TrXafytos, oblique,
and av\a%, a groove, having re-
ference to the diagonal grooving of
the premolars.) The name as-
signed to a genus of fossil herbi-
vorous marsupials, found in the
Purbeck series.

PLAGIO'STOMA. (from TrXa^os, oblique,
and a-rofia, a mouth, Gr.) A genus
of bivalve shells, first named by
LI why d and established by Mr.
Sowerby in his mineral conchology
for a generic form presumed to be
known only in a fossil state.
Certain differences of aspect in-
duced Mr. Sowerby to divide them

L A

L 356 J

P L A

into two sections, one of which has
been shewn by M. Deshayes to
pertain to the Lima, the other,
from which have been constructed
the three genera Podopsis, Pachy-
tes, and Dranchora, has likewise
been proved by M. Deshayes to be
live spondyli; the genus Plagios-
toma is therefore useless and should
expunged. The well known Pla-
giostoma Spinosune of the chalk is
a Spondylus. — Lycett.

PLANO'BBIS. (from planus, flat, and
orlis, an orb, Lat.) A genus of
discoidal, fresh-water univalves,
resembling the ammonite, but not
chambered. Planorbis belongs to
the family Pulmonea in Cuvier's
arrangement, and to Lymnacea in
Lamarck's and Blainville's. Pla-
norbes may be distinguished from
Helices by the slight increase of the
whorls of their shell, by the con-
volutions being nearly in one plane,
and by the aperture being wider
than it is high. All the shells of
this genus are reversed : they
abound in pools and ditches.

PLAN'TIGEADE. A term applied to the
feet of animals when so constructed
as to allow the sole, from the heel
to the toes, to be fairly applied to
the surface of the ground.

PL'ANULITE. The name assigned by
Lamarck to a genus of univalve
fossils formerly considered as a
species of ammonites. The planu-
lite differs from the ammonite in
not being articulated.

PLA'SMA. (from TrXao/ia, Gr. image,
this stone having been formerly
used for engraving.) A grass-green
variety of rhombohedral quartz.
Fracture conchoidal ; lustre feeble
and resinous. It occurs in beds
associated with common chalcedony.
It is brought from Italy and the
Levant : it was worn by the
Romans, and formed into orna-
mental articles of dress. By some
mineralogists, plasma is considered
to be a variety of calcedony. Spe-

cific gravity 2*55. Before the
blow-pipe it is infusible, but parts
with its colour, and becomes
whitish. According to Klaproth,
it consists of silica 96-75, alumina
0-25, iron 0'50.

PLA'STER OF PA'RIS. A sub-species
of gypsum. See Gypsum,.

PLA'STIC CLAY, (from 7r\affTiicb<?, Gr.
fit for the art of fashioning,
plastique, Fr.) The argille plas-
tique of the French geologists. A
name given to one of the beds of
the eocene period, from its easily
receiving and preserving the forms
given to it. The plastic clay
comprises the lowest formation of
deposits of the Eocene period. The
plastic clay of the Paris basin is
described as sometimes consisting
of two beds, separated by a bed of
sand. The lower bed is properly
the plastic clay. It is unctuous,
tenacious, contains some silicious
but no calcareous matter, and is
absolutely refractory in the fire,
when it has not too great a portion
of iron. It varies much in colour,
being very white, grey, yellow,
grey mixed with red, and almost
pure red. This clay is employed,
according to its quality, in making
a coarse and fine pottery and
porcelain. The French sands are
of great variety of colours. A

ries of imperfect coal occurs in
lower strata of the Paris basin.
The sands of the formation in this
country are of almost every variety
of colour, and this is more particu-
larly seen at Alum Bay, in the
Isle of Wight, where they are
employed in forming ornamental
articles resembling landscapes, by a
tasteful arrangement of them in
glass cases. The plastic clay and
the London clay are deemed by
some geologists as one formation,
and, although separated by others,
the line of separation appears to be
quite arbitrary. In some parts of
England, more particularly the

P L A

[357]

P L E

western, the plastic clay has suffered
considerable destruction. Two iso-
lated patches of it may be observed
near Weymouth. one on Came
Down, on the Ridgeway, and the
other at Black Down. Viewed on
an extended scale, the plastic clay
is composed of an indefinite number
of sand, clay, and pebble beds,
irregularly alternating, the distri-
bution of the organic remains, like
the alternation of the strata, being
exceedingly variable : sometimes
they occupy the clay ; at other
times the sand or pebbles; and
very frequently are altogether
wanting in both.

The Druid sandstones, grey
weathers, sarsenstones, and pud-
dingstones, scattered in loose blocks
over many of the chalk downs
around the London Basin, are be-
lieved by Mr. Prestwich to be con-
solidated portions of the sands and
gravels of the plastic clay series.

PLA'STEON. (plastron, Fr.) A name
given to the sternum of reptiles.

PLATE. A provincial term for shale,
or slate clay. This plate or shale
is found in the coal and associated
beds, intercalated with them.

PLA'TINA. | (platina, Spanish, from

PLA'TINUM. ) plata, silver.) A metal;
one of the simple or elementary
bodies. Platinum was not known
in Europe till Mr. Wood brought
some of it from America in 1741.
"W hen pure, it is of a white colour,
like silver, but not so bright. It
has neither taste nor smell. It is
exceedingly malleable and ductile ;
it may be hammered into plates of
extreme thinness, and Dr. Wollas-
ton succeeded in drawing out a
wire of this metal to the fineness
of l-10,000dth of an inch. Plati-
num is one of the most infusible of
metals, not yielding before the
utmost heat of the furnace ; it is
soluble in chlorine and nitro-muri-
atic acid. It was first obtained
from Choco and Santa Fe, in South

America ; it has since been discov-
ered in the Brazils, Spain, and in
the Ural mountains, in Siberia. In
the ore of platinum four new
metals have been discovered, name-
ly, iridium, palladium, osmium,
and rhodium.

PLATYCEINI'TES. (from TrXartW, broad,
and icplvov, a lily, Gr.) A genus
of the family crino'idea, of the
division, according to Miller's
arrangement, crinoidea inarticulata.
That author thus describes the gen-
eric characters of Platycrinites : —
"A crinoidal animal, with an
elliptic, or (in one species) penta-
gonal column, formed of numerous
joints, having a few side arms at
irregular distances. Pelvis, saucer-
shaped, formed of three unequal
pieces, from which five large plate-
like scapula proceed. Base pro-
vided with numerous fibres for
attachment. The want of costae,
supplied by the large plate-like
scapulae, gives the superior part of
these animals a pentagonal appear-
ance, and furnishes so conspicuous
a character, that they are readily
distinguished from all other
genera."

PLATYGNA'THUS. A genus of ichthy-
olites of the old red sandstone. A
jaw, in the possession of Dr. Traill,
that of an Orkney species of Pla-
tygnathus, does not exceed in bulk
the jaw of a full grown cod fish. —
Hugh Miller.

PLEC'TEODTTS. The name given by M.
Agassiz to a genus of fossil fishes
discovered in the Upper Ludlow
rock. The name has been chosen
from the circumstance of the teeth
being bristled with sharp points,
like the spurs of a cock. The teeth,
says M. Agassiz, cannot be referred
to any species already known, and
constitute a genus, the fishes of
which were without doubt the
pirates of the seas of that period.
If there is but one species, it might
be named Plectrodus mirabilis ; if

P L E

[ 358 ]

P L E

there are two, that with the greatest
number of points may be Plectro-
dus pleiopristris. — Murchison's

PLEISTO'CENE. A sub-division of the
Pleiocene division, implying that
it contains the maximum proportion
of the recent organisms, being from
90 to 95 per cent, of existing forms.
The Pleistocene deposits may be
defined as those in which more
then three-fourths of the fossils are
of existing species.

PLEROSA'URTJS. A fossil saurian of
the lias and oolite.

PLESIOSAT/RUS. (from TrK^alo^, near
to, and ffavpa, a lizard, Gr.) We
are indebted to the researches of the
Rev. "W. Conybeare for our earliest
acquaintance with the plesiosaurus.
A genus of extinct amphibious
animals, nearly allied to the Ich-
thyosaurus. Cuvier says this in-
habitant of the ancient world, is
perhaps the most heteroclite, and
appears to merit the name of mon-
ster above all others. " Get habit-
ant de 1'ancien monde est peut-
etre la plus heteroclite et celui de
tous qui paroit le plus meriter le
nom de monstre." It united the
teeth of a crocodile to the head of a
lizard; its neck was of enormous
length, exceeding that of its body,
and resembling the body of a ser-
pent ; it possessed a trunk and tail
of the proportions of an ordinary
quadruped ; to all these were added
the ribs of a cameleon, and the pad-
dles of a whale. The teeth were
conical, very slender, curved
inwards, finely striated on the
enamelled surface, and hollow

, throughout the interior. Five or
six species of the plesiosauri are
known ; they appear to have lived
in shallow seas and estuaries, and,
in the opinion of some, they swam
upon or near the surface, having
the neck arched, like the swan, and
darting it down at the prey within
reach. Prodigious numbers of re-

mains are found in the lias. Ver-
tebra and teeth are found in the
Hastings beds. Some of the plesi-
osauri were upwards of twenty feet
long. The plesiosaurus is supposed
to have been oviparous. Of all the
species yet discovered the most
extraordinary is the plesiosaurus
dolichodeirus, or long-necked plesi-
osaurus : the neck of this animal is
equal to half the entire length of
the body and tail united, and is
composed of 35 vertebrae ; the back
of 27, and the tail of 28 ; altogether
90 vertebras. The head does not
exceed one-fifth of the neck in
length. — Geological Transactions.

PLE'TA. An orthocerite limestone, of
a dull red and dingy-grey ; an
earthy and slightly consolidated
limestone ; with thin seams of clay.
It is placed amongst the lower
silurian rocks of Russia.

PLEFROCY'STI. The third class of
echini.

PLETJRO'TOMA. A genus of spiral
univalves, which have a narrow
aperture and long channel: the
outer lip is distinguished by a
transverse slit, about the middle or
upper part. Many species have
been found fossil in the tertiary
deposits, more especially in the
Paris basin, and in the London
clay.

PLEUROTOMA'RIA. A fossil genus of
turbinated, spiral, univalve shells
belonging to the family Turbinacea.
They are found only fossil, and
•ccur in the inferior oolite.

PLI'CATED. (from plica, Lat. to fold.)
Plaited; folded.

PLI'OCENE. | (from TrXetW, more, and

PLBI'OCENE. ) KCHVOS, recent, Gr.)
The name given by Sir C. Lyell to
a division of the supracretaceous
group, or tertiary strata. The
tertiary series Sir C. Lyell divided
into four principal groups, namely,
the eocene, the miocene, the older
pliocene, and the newer pliocene,
each characterized by containing a

L U

[ 359 ]

E

Tery different proportion of fossil
recent species. The newer pliocene,
the latest of the four, contains from
ninety to ninety-five per cent, of
recent fossils; the older pliocene
contains from thirty-five te fifty
per cent, of recent fossils ; the
miocene contains eighteen per cent,
of recent fossils ; the eocene contains
only three and a-half per cent, of
recent fossils. The newer pliocene
period is that which immediately
preceded the recent era ; the older
pliocene period is that which inter-
vened between the miocene and the
newer pliocene. The newer plio-
cene formations occur in Sicily and
Tuscany; the older pliocene at Nice,
Perpignan, Norfolk, Suffolk, and
near Sienna. Both the newer plio-
cene and the older pliocene exhibit
marine as well as fresh-water de-
posites.

PLUMB A.' GO. (plumbago, Lat.) Gra-
phite. Commonly called black-lead.

PLU'MULE. (from plumula, Lat. a
little feather.) In botany, that part
of the seed which grows into the
stem and axis of the future plant.
In the bean, horse-chesnut, &c.,
the plumule is distinctly visible,
but in plants generally, it is scarcely
perceptible without the aid of a
magnifying glass ; and in many it
does not appear till the seed begins
to germinate. The first indication
of development is the appearance
of the plumule, which is a collec-
tion of feathery fibres, bursting from
the enveloping capsule of the germ,
and which proceeds immediately to
extend itself vertically upwards.

PLTJTO'NIC. (from Pluto, one of the
heathen deities.) A name given
to certain rocks elaborated in the
deep recesses of the earth, from
the opinion they were formed by
igneous action at great depths;
whereas the volcanic, although they
may have risen up from below,
have cooled from a melted state
upon or near the surface.

PLTJTO'NTC EOCKS. TJnstratified crys-
talline rocks, such as granites,
greenstones, and others, of igneous
origin, formed at great depths from
the surface. Plutonic rocks are
distinguished from those which are
called volcanic, although they are
both igneous; Plutonic rocks having
been elaborated in the deep recesses
of the earth, while the volcanic are
solidified at or near the surface.
Plutonic rocks differ from volcanic,'
not only by their more crystalline
texture, but also by the absence of
tuffs and breccias, which are the
products of eruptions at the earth's
surface. They differ also by the
absence of pores or cellular cavities,
which the entangled gases give rise
to in ordinary lava. — Lyell.

PNETJMA'TICS. (from Trvevpcnucj), Gr.)
That branch of science which
relates to the equilibrium or move-
ments of aerial fluids under all
circumstances of pressure, density,
and elasticity. The weight of the
air, and its pressure on all the
bodies on the earth's surface, were
quite unknown to the ancients,
and only first perceived by Galileo,
on the occasion of a sucking-pump
refusing to draw water above a
certain height. The manner in
which the observed law of equilib-
rium of an elastic fluid, like air,
may be considered to originate in
the mutual repulsion of its particles,
has been investigated by Newton,
and the actual state of the law
itself, as announced by Mariotte,
" that the density of the air, or the
quantity of it contained in the same
space, is, caeteris paribus, propor-
tioned to the pressure it supports,"
has been verified by direct experi-
ment. This law contains the
principal of solution of every dy-
namical question that can occur re-
lative to the equilibrium of elastic
fluids, and is therefore to be re-
garded as one of the highest axioms
in the science of pneumatics.

P 0 C

[ 360 ]

POL

POCILLO'PORA. A genus of stony
polypifers, thus named from the
pocilliform shape of the cells, from
which shape, as well as the margins
having little or no projection, this
genus is separated from madrepora.
Pocillopara is plant-formed, ramose
or lobated; the surface set with
deep cellules, with porous inter-
stices. There are several species,
found principally in the South sea
and Indian ocean.

PODOPHTHA'LMIA. The first order of
the class Crustacea, comprising the
lobster, crab, crayfish, &c.

PODOPHTHA'LMA. The name assigned
by Leach to a group of crustaceans
comprising the orders Decapoda and
Stomatopoda. The animals of this
group have their eyes supported on
moveable peduncles.

POIKILITIC. (from 77-ot/aXos, Gr. va-
rious, variegated.) To the new
red sandstone group, M. Brongniart
has applied the name of Terrain
Pcecilien. Conybeare has proposed
to extend the term Pcecilitic to the
entire group of strata between the
coal formation and the lias, com-
prising the new red conglomerate,
the magnesian limestone, the varie-
gated sandstone, the shell limestone,
and the variegated marl. Some
common appellative, says Buckland,
for all these formations has been
long a desideratum in geology ; but
the word pcecititw is, in sound, so
like pisolite, that it may be better
to adhere more literally to the
Greek root, and apply the common
name of Poikilitic group to the
strata in question.

POLAEIZED LIGHT. Light which by
reflection or refraction, at a certain
angle, or by refraction in certain
crystals, has acquired the property
of exhibiting opposite effects in
planes at right angles to each other.

POLISHING SLATE. (Poherschiefer of
Werner.) A variety of tripoli.
Colour white, yellowish- white, or
yellow. Structure slaty. Cross-

fracture dull and earthy. It is
very light, so as sometimes to swim
on water, strongly adheres to the
tongue, and is easily reduced to a
fine dry powder. Before the blow-
pipe it hardens, but does not fuse.
It principally occurs at Bilin, in
Bohemia, and is regarded as a
volcanic production.

PO'LLEN. fpollen, Lat. fine flour.)
In botany, the fecundating powder
or dust contained in the anther.
In dry and warm weather the
anther bursts, and the pollen is
thrown out.

POLTCH'(ETA. The first order of the
class annulata, comprising the
Nereis, serpula, and lob- worm.

POLYGA'STKICA. (from TroXvs, many,
and <ya<nrjp, a stomach, Gr.) So
named from their possessing numer-
ous internal digestive cavities. The
lowest class of animals, belonging
to Diploneura, or Helminthoida.

When we place, says Professor
Grant, a drop of any decayed infu-
sion of animal or vegetable matter
under a powerful microscope, and
throw a light through that drop,
and through the microscope to the
eye, we discover in the drop of
water various forms of living
beings ; some of a rounded, some
of a lengthened form, and some
exhibiting ramifications shooting
in all directions, but all apparently
of a soft, transparent, gelatinous,
and almost homogeneous texture.
In these minute animals there are
numerous cavities or stomachs, in
some of them being two hundred
in number. There is every reason
to believe that polygastrica exist
in every drop of water. They
form the food of other classes, more
especially the zoophytes. Almost
all the known genera of polygastric
animalcules possess eyes : they are
also found to possess an acute sense
of taste ; they distinguish, pursue,
and seize their prey, and, although
so excessively minute that five

POL

[361 ]

POL

millions have been calculated as
being contained in one drop of
water, they avoid infringing on
one another while swimming. All
their movements appear to be as
well directed, regular, methodical,
and spontaneous, as those of the
higher classes of swimming animals.
These movements are effected by
means of very minute, hair- like,
tapering, transparent, vibratile fila-
ments disposed frequently around
the mouth, where they are gene-
rally largest and longest. There is
no proper skeleton in the whole
order polygastrica, nor any secre-
tion of shell on the surface, yet
there are parts destined to give
support : no nervous system has
hitherto been detected in the poly-
gastric animals. Some of the
poly gastric animals exude on their
surface a secretion which aggluti-
nates foreign particles floating in
the waters which surround them,
and thus form for themselves a
partial covering. In the majority
of polygastric animals there is an
alimentary canal, with an oral and
an anal orifice, which traverses the
body ; in the simplest forms of
animalcules, however, there is but
one general orifice to the alimentary
cavities, which is placed at the
anterior extremity of the body, and
is surrounded with long vibratile
cilia, which serve both as organs of
motion and tentacula. No teeth
for mastication, nor any glandular
organs to assist in digestion, have
been discovered in them. Not-
withstanding their extreme minute-
ness, they appear to be the most
numerous, the most prolific, the
most active, and the most voracious
of all living beings. Some natu-
ralists, like Lamarck, believed that
these animals were without a
mouth or any internal organs, and
were nourished by superficial ab-
sorption, like marine plants.
Lewenhoeck and Ellis, however,

observed that they possessed an in-
ternal cavity, and devoured each
other. Spallanzani perceived them
swallowing each other so avari-
ciously that their bodies became
distended with their prey. — Lec-
tures on Comp. Anatomy, passim.

POLYHA'LLITE. A mineral found at
Ischel, in Austria. It occurs in
masses of a fibrous texture. Lustre
pearly. Specific gravity 2'76.

POLYME'KIC ISOMORPHISM. The re-
placement of an equivalent by a
multiple of another, is termed poly-
meric isomorphism. — Jukes.

POLYMI'GNITE. (from TTO\VS, many,
and fijywjii, to mix, Gr.) A min-
eral, thus named in consequence of
the variety of its constituent parts.
It consists of titanic acid, zirconia,
lime, yttria, the oxides of iron,
cerium, and manganese, with mi-
nute portions of magnesia, potash,
silica, and oxide of tin. It is of a
black colour ; crystallized in small
prisms ; scratches glass ; specific
gravity 4-8. Fracture conchoidal.
Lustre almost metallic.

PO'LYPE. The name given to each
tube, surrounded with its tentacula,
of the Polypus.

POLYPA'KIA. } The fourth class of Ea-

PO'LYPI. ) diata or Zoophytes;
thus named from a supposed re-
semblance to an Octopus, called
Polypus by the ancients, this re-
semblance arising from the arrange-
ment of the tentacula around the
mouth.

The polypi constitute the second
class (the Infusoria forming the
first) of Lamarck, and form a large
family of animals, in which we
trace a gradual process to a more
complicated organization. They,
according to Lamarck, have a gela-
tinous, contractile body, a distinct
mouth, surrounded by tentacula, or
branching arms, and a simple ali-
mentary canal or stomach, showing
no vents; they increase by separa-
tion, or internal spontaneous pro-
2 A

POL

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POL

•duction, and show no generative
organs. The greater part of the
species adhere one to another, and
may be considered as animals de-
pending on mutual support. Some
of them approach closely to the
Infusoria, as the Polypi Ciliati,
whilst others are capable of attach-
ing themselves by means of a pedi-
cle, and in many instances are able
to detach and affix themselves to
new spots.

These animals are commonly
known as Corals. From an idea
which long prevailed that these
animals are allied to marine plants,
they also obtained the name of
Zoophytes. The body is cylindri-
cal or conical, sometimes possessing
no viscus but its cavity ; at others
possessing a stomach, which is vi-
sible, and other organs. The
greater number of Polyparia are
inhabitants of the ocean, and from
the ocean's depths they raise those
immense reefs that at some future
period may form a communication
between the inhabitants of the
temperate zones. Although Polypi
abound in every part of the ocean,
still it is in the warmer regions
that they grow in greatest luxuri-
ance. The tentacula of Polypi are
exquisitely sensitive, and are fre-
quently seen, either singly or alto-
gether, bending their extremities
towards the mouth when any mi-
nute floating body comes in contact
with them. A question arises,
says Dr. Eoget, with regard to the
constitution of these Zoophytes,
similar to that which has been
proposed with regard to trees,
namely, what limit should be as-
signed to their individuality ? Is
the whole mass, which appears to
grow from one root, and which
consists of multitudes of branches,
proceeding from a common stem,
to be considered as one individual
animal, or is it an assemblage, or
aggregation of smaller individuals ;

each individual being characterised
by having a single mouth, with its
accompanying tentacula, and yet
the whole being animated by a com-
mon principle of life and growth ?
The greater number of naturalists
have adopted this latter view, re-
garding each portion as provided
with a distinct circle of tentacula,
as a separate animal, associated
with its neighbours in the con-
struction of a common habitation,
and contributing its quota to the
general nourishment of this animal
republic.

POLYPHRA'CTUS. A genus of ichthyo-
lites of the old red sandstone.

POLYPI'FERA. j That class of animals

POLYPI'PHERA. j commonly known
by the name of Zoophytes. They
are carnivorous, feeding upon living
animalcules. These animals preci-
pitate immense quantities of carbo-
nate of lime, especially in tropical
seas.

" These," says Prof. Grant, " are
soft aquatic animals of a plant-like
form, generally fixed, and supported
by an extra- vascular axis of a cal-
careous or horny texture. Instead
of the pores of the poriphora, the
common fleshy mass of the body
here developes small tubular di-
gestive sacs called polypi, the
margins of which are furnished
with sensitive tentacula, and the
sides of the tentacula are almost
always furnished with sensitive, or
prehensile, or vibratile cilia."

POLYPI'FEROTJS. Animals which have
polypi ; zoophytes.

POLYPE'TALOUS. (from TTO\VS, many,
and Tre-raXov, a leaf of the corolla,
Gr.) In botany, a term applied to
a corolla which has the petals sepa-
rate.

POLYSE'PALOFS. (from 7ro\i><?, many,
and sepal, the name given to the
parts of which the calyx is compo-
sed.) In botany, a term given to
a calyx which has its sepals sepa-
rate from each other.

POL

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P 0 R

POLYPOTHE'CIA. A genus of spongeous
zoophytes found in flints, and thus
named by Miss Bennett, of Korton
House, near Warminster.

POLY'PTERUS. A genus of fishes found
in the Nile and in the rivers of
Senegal. The Polypterus and Le-
pidosteus are the only known
genera of living representatives of
the sauroid fishes.

POLYSP'ERMOUS. (from TroXvs, many,
and mrepfia, seed, Gr.) In botany,
a term applied to the ovarium and
fruit, when they contain many
seeds.

POLYTHA'LAMOUS. (from TTO\VS, many,
and 6d\afio<s, a chamber, Gr.)
Having many cells or chambers,
as polytJialanwus shells ; multilo-
eular; camerated.

POLYZO'A. Called also Bryoza: the
second order of the class Mol-
luscoidea, comprising flustra, rete-
pora, eschara, and other zoophytes.

PO'RCELAIN EARTH. | For a descrip-

PO'RCELAIN CLAY. ) tion of this,
See China Clay.

PO'RCELAIN JAS'PER. A variety of
jasper ; called also Porcellanite.
see Porcellanite.

PGRCELANA'CEOUS. | Resembling por-

PORCELA'NEOUS. ) celain. Shells
have been divided into two classes.
The first are of a compact texture,
have an enamelled surface, and are
generally beautifully variegated ;
the shells of this class have been
termed porcelanaceous, or porcela-
neous shells; they contain but a
small proportion of soft animal
matter.

PORC'ELAINOTJS. The name given to a
species of protogine. Porcelainous
Protogine, or China Stone, is com-
posed of felspar quartz and talc,
and is of a greenish-yellow colour.
It affords, by decomposition, the
china clay of commerce.

PORCE'LLANITE. The Porzellan Jaspis
of Werner; Thermautide porcel-
lanite of Haiiy; Porcellanite of
Kir wan. This is a variety of

Jasper, according to some miner-
alogists ; Prof. Jameson places
it as a sub-species. Mr. Allan,
however, says "it is merely clay
indurated by heat ;" and according
to Werner, it is siate-clay converted
into a kind of porcelain by the
action of the heat of the volcano.
"A mineral of various colours,
from grey to nearly black, occur-
ring in amphorous masses or frag-
ments, which are often rifted.
Porcellanite sometimes resembles a
brick which has undergone a slight
vitrification. Its fracture is im-
perfectly conchoidal or uneven,
more or less glistening, and often
has the aspect of certain porcelains.
It is opaque, very brittle, and less
hard than quartz. An analysis, of
of it yielded silex 60 '75, alumine
27'25, potash 3 66, magnesia 3,
oxide of iron 2 '50. It is most
likely an alteration of some variety
of argillaceous slate by pseudo-
volcanic fires : it does not con-
stitute a distinct species. It is
found in large masses near the
pitch-lake in Trinidad, and occurs
usually in the vicinity of coal
mines." — Cleaveland.
POR'CELAIN SPAR. A mineral combi-
nation with a chloride, consisting
of four equivalents of the double
silicate of lime and alumina with
one of chloride of sodium.
PORI'FERA, | (from porus, a pore,
PORI'PHERA. ) and fero, to bear.)
A classs of animals belonging to
Cyclo-]X"eura, or Radiata. Pori-
phera constitutes the second lowest
class of animals, coming between
PolypipheraandPolygastrica. They
form the various species of sponge
which are met with in such mul-
titudes on every rocky coast of the
ocean, from the shores of Greenland
to those of Australia. Their sur-
face is porous ; those pores lead to
canals which ramify through all
parts of their texture ; and those
canals anastomosing into larger and

P 0 R

[ 364

P 0 R

larger trunks, lead, again, to ori-
•fices on the surface, from which
there issues constant streams of
water. The poriferous animals
present various and remarkable
forms in the skeleton ; and the
simple gelatinous body of the
animal is supported by a skeleton
composed of different kinds of
earth : in one group the earth is
silica; in another it is the carbonate
of lime ; in another it is a horny
substance. The skeleton, thus
composed, has been called the axis
of the animal. The material of
which the fleshy portion is com-
posed is of so tender and gelatinous
a nature, that the slightest pressure
is sufficient to tear it asunder, and
allow the fluid parts to escape,
and the whole soon melts away
into a thin oily liquid.

The surface of a living sponge

E resents two kinds of orifices ; the
irger of a rounded shape with
raised margins, which form pro-
jecting papillae ; the smaller, mi-
nute and numerous, constituting
the pores of the sponge. TJie
porifera present a digestive system,
which, by its form and simplicity,
approaches the nearest to that of
plants. The cellular tissue of their
body is permeated in all directions
by anastomosing and ramifying
canals, which begin by minute
superficial pores, closely distributed
over every part, and terminate in
larger orifices variously placed,
according to the form of the entire
animal. The pores are provided
with a gelatinous network and pro-
jecting spicula, to protect them
from the larger animalcules and
floating particles. The internal
canals, like the venous system,
leading from capillaries to trunks,
are bounded by a more condensed
portion of the general cellular sub-
stance of the body, and are inces-
santly traversed by streams of
water, passing inwards through

the minute pores, and discharged
through the larger orifices or vents,
but no polypi or cilia have been
discovered in those parts, although
from analogy we might consider
them necessary. From the inces-
sant streams that are conveyed
through the bodies of these animals,
it appears that all parts of these
interior perforations, as well as the
general external surface of this
cellular structure, serve for the
conveyance of nutritious matter
into the interior substance of the
body. On watching the streams of
water which issue from the foecal
orifices, there may be seen minute
flocculent particles that are inces-
santly detached and thrown out,
which appear as if they were the
residue of digestion, or pellicles
excreted from the body, and thrown
off from the surface of internal
canals.

No nervous filaments have been
detected in the soft gelatinous
bodies of poriphera. Their ciliated
gemmules, however, are endowed
with remarkable living properties,
and powers of spontaneous motion.
They have an evident object in
their motions ; they can accelerate,
retard, or cease, at pleasure, the
vibrations of their cilia ; they can
change the direction of their course
in the water, perceive each other's
vicinity, revolve round each other,
distinguish the most suitable place
for the fixing of each species, or
bound forward suddenly from a
state of rest. They appear in this
state of freedom to be sensible to
light, and to shun it.

Although sponges, or poriferous
animals, are permanently attached
to rocks, and other solid bodies in
the ocean, and are consequently
destined to an existence as com-
pletely stationary as that of plants,
yet such is not the condition of the
earlier, and more transitory stages
of their development. On the

r o E

gemmule the power of locomotion
is conferred, until it has found for
itself a proper habitation ; this
chosen, it there fixes itself and
there continues for the remaining
period of its existence.

POEI'PHEEOTJS. Possessing pores ;
animals belonging to the class pori-
phera. The alimentary apparatus
of poripJierous animals approaches
the nearest to that of plants.

PO'BPHYEY. (from tropcfrvpa, purple,
Gr.) Porphyry has been so called
in reference to the purple, or
reddish, colour so commonly per-
ceptible in it. Generally, any form
of rock in which one or more
minerals are scattered through an
earthy or compact base. Porphyry
has generally a compact texture.
Sometimes it is composed of tabu-
lar, columnar, or globular distinct
concretions ; and not unfrequently
it is traversed by numerous seams
and rents. There are many va-
rieties of porphyry, named accord-
ing to the base of each, as Petro-
siliceous Porphyry, Felspar Por-
phyry, Clinkstone Porphyry, Ar-
gillaceous Porphyry, &c. Porphyry
occurs in enormous masses ; at the
head of Glen Ptarmagan, a cliff of
porphyry fifteen hundred feet in
height, in shape resembling an
oblique truncated pyramid, passes
through granite. In some in-
stances porphyry is, beyond all
question, a volcanic formation.
Near Christiana, in Norway, an
immense mass of porphyry, from
1600 to 2000 feet in thickness,
covers beds of gneiss, limestone,
and greywacke. Dykes of por-
phyry cutting through the sub-
jacent rocks indisputably prove the
volcanic character of this immense
mass.

POEPHYEI'TIC. } Resembling por-

PORPHYKA'CEOTTS. ) phyry; contain-
ing porphyry ; composed of a
compact homogeneous rock, in
which distinct crystals or grains

L 365 ] POT

are imbedded : the compact stone
is called the base, and sometimes
the paste. The base, or paste, is
generally felspar.

POEI'TES. A genus of stony polypi-
fers, fixed; ramified; or lobated
and obtuse; the outer surface
everywhere stellated.

PO'ETLAND BEDS. A marine forma-
tion, occurring in the Isle of Port-
land and in Wiltshire. These beds
consist of coarse shelly limestone,
fine grained white limestone, and
compact limestone, all possessing
an oolitic structure ; and beds of
chert. The Portland beds lie im-
mediately under the Purbeck beds,
and above the Kimmeridge clay.
They constitute the uppermost
members of the oolite group, and
abound in ammonites, trigoniae, &c.

PO'ETLAND L'IMESTONE. ") One of the

PO'ETLAND OOLITE. j members of
the Portland beds ; a marine oolitic
formation, obtained principally
from Portland, whence the name,
and used in building. The Port-
land limestone abounds in trigoniae,
ammonites, pernae, pleurotomarias,
and other marine shells.

PO'ETLAND SANDS. A name given to
one of the divisions of the Portland"
oolite. These beds consist of white
and green sand and sandstone, with
concretionary masses of grit ; the
lower strata argillaceous. — Mantell.

POST. A north of England term for
any bed of firm rock; generally
applied to sandstone.

POST PLF/IOCENE. See Quaternary.

PO'TASH. An alkali obtained by the
incineration of vegetables, or the
woody parts of plants that do
not grow near the sea. The water
in which the ashes are washed is
evaporated in iron pots, from which
circumstance it was called potash.
There are few, if any, of the inferior
stratified rocks without potash ;
and, viewing them in the mass,
potash may be considered as con-
stituting five or six per cent, of

POT

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P R E

the whole. Potash may he re-
garded as constituting between six
and seven per cent, of granites,
greenstones, and rocks of that class.

POTA'SSITJM. A metal discovered by
Sir H. Davy in 1808. At a tem-
perature of 32° potassium is hard
and brittle, with a crystalline tex-
ture ; at 50° it becomes malleable,
with a lustre like that of polished
silver; and at 150° it fuses. Po-
tassium is lighter than water, its
specific gravity being 0'85 ; to
preserve it unchanged, it should be
kept in a phial with pure naptha.

POTEEIOCEINI'TES. (from TroTrjpiov,
a cup, and Kplvov, a lily, Gr.)
Vase-like, lily-shaped animal. A
genus of Crino'idea, belonging to
the division crinoi'dea semiarticu-
lata, according to Miller's arrange-
ment. That author thus describes
the generic characters of Poterio-
crinites. " A crinoidal animal,
with a round column composed of
numerous thin joints, having in
their centre a round alimentary
canal, and articulating by surfaces
striated in radii. Hound auxiliary
side arms, proceeding at irregular
distances from the column. Pelvis
formed of five pentagonal plate-
like joints, supporting five hexa-
gonal intercostal plate-like joints,
and five plate-like scapulae, having
on one of the intercostal s an inter-
scapulary plate interposed. An
arm proceeding from each of the
scapulae. Base, probably fascicular,
and permanently adhering."

PO'TSTONE. The Lapis ollaris of Pliny.
A variety of steatite, nearly equal
in hardness to common steatite ; it
is, however, more tenacious, and
though it may be turned with the
lathe, it breaks with difficulty. It
is smooth and unctuous to the
touch. It is usually of a greenish-
grey colour, with various shades,
and often spotted. Its fracture
curved, and, sometimes, almost
foliated. Specific gravity from

2-8 to 3-2. It emits an argillaceous
odour when breathed on. From
its being formed into culinary
vessels it has obtained its name.
From an analysis by "Weigleb, the
potstone of Corno, in Lombardy,
where it occurs in great abundance,
consists of magnesia 38, silica 38,
alumina 7, iron 15, carbonate of
lime 1, fluoric acid 1.

PO'TTEES' CLAY. A variety of clay,
of a reddish or grey colour, which
becomes red when heated. That
used in our potteries for making
coarse red ware comes chiefly from
Devonshire. It is exceedingly
infusible, and contains a large
proportion of alumine. Potter's
clay, mixed with ground flints, is
employed in the manufacture of
the finer kinds of pottery in
Staffordshire.

POZZUOLA'KA. Scoriae or volcanic
ashes, brought from Pozzuoli, a
town in the bay of Naples, and
named therefrom. Pozzuolana is
used, mixed with lime, for making
Roman, or water-setting, cement.

PEASE, (from irpaaov, Gr. a leek;
so called from its colour.) The
Prasem of "Werner ; Quartz hyalin
vert obscur of Haiiy ; Quartz prase
of Brongniart. A leek-green trans-
lucent variety of rhombohedral
quartz ; lustre vitreous ; fracture
splintery. Specific gravity 2'5.
Prase appears to be common quartz,
coloured by actynolite or epidote.

PBA'SINOUS. (prasinus, Lat.) Of a
light green colour, inclining to
yellow.

PEE'HNITE. A mineral thus named
after Colonel Prehn, who brought
it from the Cape of Good Hope.
Prehnite is of a green, grey, or
white colour. It occurs crystal-
lised ; in granular, scopiform, and
stellular fibrous distinct concretions;
massive and reniform. Its texture
is foliated. Fracture uneven. In-
ternal lustre pearly. It scratches
glass, though feebly, and gives

P E I

[367]

P E I

sparks with, steel. Specific gravity
from 2-60 to 2*94. Hardness 6
to 7. Veins of prehnite occur in
Cornwall ; they are very irregular,
both in size and direction. As-
bestus and stilbite have been found
in the veins with the prehnite.

PRIMARY. 1 . In astronomy, the planet
about which a satellite revolves.
The planetary bodies which revolve
round the sun, and not round any
other body, are called primary
planets, or primaries. Some of
the planets are accompanied by
satellites or moons, which revolve
round their primary, in a manner
similar to the revolution of our
moon.

2. A term applied to rocks or
strata, because it was supposed,
from the absence of fossil remains,
that they were formed before ani-
mals and vegetables ; as well as
that they were the first rocks
formed. Sir C. Lyell proposes to
substitute the word hypogene for
primary.

PRIMARY FORM. In mineralogy, that
form to which minerals may be
reduced by cleavage, and which is
no longer changed by continued
cleavage. If a mineral can be
cleaved in directions which produce
only one particular form that form
is denominated its primary. The
whole number of primary forms
are comprised in the regular tetra-
hedron, the cube, the rhombic do-
decahedron, the octahedron, the
six-sided prism, and the parallele-
piped.

PRIMARY LIMES'TONE. This, says
Jukes, instead of primary, ought to
be simply called altered limestone.
It is always highly crystalline,
generally has lost all appearance of
bedding, and is a granular crystal-
line carbonate of lime.

PRI'MARY STRATA. The primary strata
are defined above by the old red
sandstone ; and when that is absent,
by the carboniferous limestone;

below, they usually rest, but some-
times unconformably, upon granite.
They consist, in a great measure,
of mechanical aggregates, compara-
ble with sandstones and clays, but
yet generally distinguishable by
superior hardness, and somewhat
of a crystalline structure in mass,
or texture in detail, from the se-
condary rocks. In the secondary
rocks there is more variety of aren-
aceous and calcareous members.
In the tertiary strata loose sands,
marls, and clays abound, while
these scarcely occur at all among
the primary rocks. — Prof. Phillips.

PRIMITIVE. A term applied to cer-
tain rocks, from the circumstance
of no fossil remains of animals or
vegetables, nor any fragments of
other rocks, being found in them.
The term has given way to what is
considered a more appropriate one,
namely, primary, and primary has
given way to Palaeozoic.

PRISM. (Trpiffjua, Gr. prisme, Pr.
prisma, It.) A solid figure, the
ends whereof are parallel, equal,
and similar plane figures, and the
sides which connect the ends are
parallelograms. Prisms take par-
ticular names from the figure of
their bases or ends, namely, triangu-
lar, square, rectangular, pentagonal,
hexagonal, &c.

" A prism is rarely found having
only three, very commonly four,
six, eight, or even more sides ; the
sides, or lateral planes, surround
its axis, which is an imaginary
line passing down the middle of
the prism, from the centre of the
upper terminal plane to the centre
of the lower ; the terminal planes
being also called the bases. But
prisms are found both very long
and very short; when long, and
the crystals slender and curved,
they are termed capillary, when
straight, acicular ; when the prism
is short, the crystal is said to be
tabular"— Phillips.

P R I

[_ 368 ]

PRO

PIU'STIS. The fossil saw-fish.

PROBOSCI'DIA. A family of quadru-
peds belonging to the order Pachy-
derm ata, or, according to more
recent classification, the sixth order
of the sub-class Placentalia, class
Mammalia. The proboscidians have
five toes to each, foot ; they possess
no canine teeth, but two tusks,
which project from the mouth, and
frequently attain to an immense
size. The nostrils are continued
out into a proboscis, which is ex-
ceedingly flexible, possesses great
sensitiveness, and terminates in a
finger-like appendage. The pro-
boscis may be considered as the
hand of the elephant.

PBOBO'SCTS. (jrpopoGia<$, Gr. from
/3o5/cw, to feed, and Trpo, before.)
A lengthened tube, snout, or trunk
belonging to certain animals. The
proboscis of the elephant is of
great length, serving the purposes
of a hand, conveying to the mouth
anything it desires to swallow. It
is an instrument of most delicate
touch, of scent, and breathing, and
of prehension as adroit as that of a
hand. In insects, when the in-
strument for suction extends for
some length from the mouth, it is
called a proboscis ; such is the ap-
paratus of the butterfly, the moth,
the gnat, the house-fly, &c.

PEODTJ'CTA. j An extinct genus of

PEODTJ'CTTJS. j equilateral inequivalve,
striated bivalves. The name Pro-
ducta has been, by some, objected
to, and that of Leptsena has been
assigned by Dalman. The genus
Producta has not hitherto been
found in any deposit more recent
than the magnesian limestone or
zechstein.

PEOTE'OLITE. (from irpunews and \iOos,
Gr.) The name assigned by Dr.
Boase to a genus of schistose rocks.
He says, " in many parts of Corn-
wall, the schistose rocks adjoining
the granite, have a basis more
granular than that of cornubianite j

are much softer, and more prone to
disintegrate : following, therefore,
the plan adopted in the instance of
eurite and felsparite, these may be
referred to a distinct genus which,
on account of the various appear-
ances it assumes, may be called
proteolite. It may be divided into
two families; mica being the ac-
cessory mineral in the one ; shorl
in the other. Proteolite, like cor-
nubianite, consists of a basis of
compact felspar with mica or shorl,
but its ingredients are differently
aggregated, and its felspathic basis
is softer, granular, and more prone
to disintegration."

PEO'TEUS. (w/oorevs, Gr. proteus, Lat.)
The name given to a genus of the
order Batrachia. One species only
has been hitherto discovered, name-
ly, the Proteus Anguinus. A sub-
terranean saurian, which never
makes its appearance on the earth's
surface, but is always concealed at
a considerable depth below it, being
found in subterraneous lakes and
caves two or three hundred feet
below the surface of the ground.
The following particulars are ex-
tracted from Sir H. Davy's Conso-
lations in Travel : — " Independent-
ly of the natural beauties found in
Illyria, and the various sources of
amusement which a traveller, fond
of natural history, may find in this
region, it has a peculiar object of
interest in the extraordinary ani-
mals which are found in the bottom
of its subterraneous cavities, namely
the Proteus anguinus, a far greater
wonder of nature than any of those
which the Baron Yalvasor detailed
to the Royal Society a century and
a half ago, as belonging to Carniola.
At first view, you might suppose
this animal to be a lizard, but it
has the motions of a fish. Its head,
and the lower parts of its body,
and its tail, bear a strong resem-
blance to those of the eel ; but it
has no fins ; and its curious bron-

PRO

L 369 1

PRO

chial organs are not like the gills
of fishes; they form a singular
vascular structure, almost like a
crest, round the throat, which may
be removed without occasioning
the death of the animal, who is
likewise furnished with lungs.
"With this douhle apparatus for
supplying air to the blood, it can
either live below or above the
water. Its fore feet resemble
hands, but they have only three
claws or fingers, and are too feeble
to be of use in grasping or support-
ing the weight of the animal ; the
hinder feet have only two claws or
toes, and in the larger specimens
these are found so imperfect as to be
almost obliterated. It has small
points instead of eyes, as if to
preserve the analogy of nature. It
is of a fleshy whiteness or trans-
parency in its natural state, but
when exposed to light, its skin
gradually becomes darker, and at
last gains an olive tint. Its nasal
organs appear large and it is
abundantly furnished with teeth,
from which it may be concluded
that it is an animal of prey ; yet in
its confined state it has never been
known to eat, and it has been kept
alive for many years by occasionally
changing the water in which it is
placed. The proteus was first
discovered in Illyria by the late
Baron Zois ; but it has been re-
ported that some individuals of the
same species have been recognized
in the calcareous strata in Sicily."
The proteus has been found of
various sizes, from that of the
thickness of a quill to that of the
thumb, but its form of organs has
always been the same. It is a
perfect animal of a peculiar species,
and it adds one instance more to
the number already known, of the
wonderful manner in which life is
produced and perpetuated in every
part of the globe, even in places
which seem the least suited to

organized existences. And the
same Infinite Power and Wisdom
which has fitted the camel and the
o.strich for the deserts of Africa,
the whale for the Polar seas, and
the morse and the white bear for
the Arctic ice, has given the
proteus to the deep and dark sub-
terraneous lakes of Illyria, — an
animal to whom the presence of
light is not essential, and who can
live indifferently in air and in
water, on the surface of the rock,
or in the mud. The organization
of the spine of the proteus is analo-
gous to that of one of the sauri,
the remains of which are found in
the older secondary strata. The
problem of the reproduction of the
proteus, like that of the eel, is not
yet solved, but ovaria have been
discovered in animals of both
species.

2. This name is also given to a
species of infusoria. Of these, the
most singular, says Dr. Roget, is
the Proteus, which cannot, indeed,
be said to have any determinate
shape ; for it seldom remains the
same for two minutes together. It
looks like a mass of soft jelly,
highly irritable and contractile in
every part ; at one time wholly
shrunk into a ball, at another
stretched out into a lengthened
riband; and again, at another
moment, perhaps, we find it
doubled upon itself like a leech.
If we watch its motions for any
time, we see some parts shooting
out, as if suddenly inflated, and
branching forth into star-like radi-
ations, or assuming various gro-
tesque shapes, while other parts
will, in like manner, be as quickly
contracted. Thus the whole figure
may, in an instant, be completely
changed, by metamorphoses as rapid
as they are irregular and capricious.
PEOTHE'EITE. A mineral species, oc-
curring in the valley of the Ziller-
thal, in the Tyrol.

PRO

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P S E

PBOTOCO'CCUS NIVA'LIS. The name
given to an extremely minute plant
which grows upon the surface of
the snow in certain regions, im-
parting to the snow a red appear-
ance, from which circumstance it
was at first supposed that the snow
itself was red. Mr. Darwin, in his
account of his passage of the Cor-
dillera of the Andes, thus describes
it: "On several of the patches of
perpetual snow, I found the Pro-
toccocus Nivalis, or red snow, so
well known from the accounts of
Arctic navigators. My attention
was called to the circumstance from
observing the footsteps of the mules
stained a pale red, as if their hoofs
had been slightly bloody. I, at
first, thought it was owing to dust
blown from the surrounding moun-
tains of red porphyry, for from the
magnifying power of the crystals
of snow, the groups of these atom-
like plants appeared like coarse
particles. The snow was coloured
only where it had thawed rapidly,
or had been accidentally crushed.
A small portion of it rubbed on
paper communicated a faint rose
tinge, mingled with a little brick-
red. I placed some of the snow
between the leaves of my pocket-
book, and a month afterwards ex-
amined with care the pale disco-
loured patches on the paper. The
specimens, when scraped off, were
of a spherical form, with a diameter
of the thousandth of an inch. The
central part consists of a blood-red
substance, surrounded by a colour-
less bark. "When living on the
snow they are collected in groups,
many lying close together. The
dried specimens placed in any fluid,
as water, spirits of wine, or diluted
sulphuric acid, were acted on in
two different ways : sometimes an
expansion was caused, at others a
contraction. The central part after
immersion invariably appeared as
a drop of red oily fluid, containing

a few most minute granules ; and
these probably are the germs of
new individuals."

PKO'TOGINE. A term applied by the
French to the talcose granite of
the Alps. The name given to a
granite composed of felspar, quartz,
and talc or chlorite ; the talc sup-
plying the place of mica. Protogine
is distinguished from granite not
only in the substitution of talc for
mica, but also in its great tendency
to disintegration. Dr. Boase di-
vides protogine into five species,
namely, porcelainous, shorlaceous,
fluoric, porphyritic, and quartzose.
These are all found in Cornwall.

PBOTOZO'A. A sub-kingdom of ani-
mals comprising the two classes,
Stomatoda and Astomata.

PBOTOZO'IC. (from Trpwros, first, and
£uW, animal, Gr.) A name pro-
posed by Sir E.. Murchison to be
given to those rocks which are
supposed to contain the remains of
the first formed animals or vegeta-
bles ; the first or lowest formations
in which animals or vegetables
occur. " That there is a limit in
the descending scale of formations,
beneath which no traces of life
have been discovered, is now pretty
generally recognized ; and looking
merely to this fact, geologists may
agree to use the term Protowicy
however they may differ in their
interpretation of the phenomenon."
— Sir It. MurcJdson.

PBI/INOSE. (from pruina, Lat. a
frost, or rime.) In entomology,
applied to the clothing of insects
when covered with a minute dust,
scarcely discoverable by the lens.

PSAMMO'BIA. A small bivalve found
in the cyclas limestone of Burwash.

PSAHMO'STEUS. A genus of ichthyo-
lites of the old red sandstone, of
which Agassiz, in his Poissons
Fossiles, describes four species.

PSEU'DO. (^e££o9, Gr. false.) A
term generally used as a prefix to,
and in composition with, other

P S E

[ 371 ]

P T E

words ; it implies a sense of spuri-
ousness, as, for example, a pseudo-
tuber is a false tuber; pseudo-
galena is false galena; a pseudo-
volcano is a coal mine in a state of
combustion.

PSEUDOMO'RPH. (from tyevSos, false,
and floppy, form, Gr.) A Pseudo-
morph is one mineral occurring in
the crystalline form of another.

PSEUDOMORPHISM. That process by
which the constituents of minerals
are changed, and the place of the
removed constituent is supplied by
the presence of another of the same
form.

PTERA'SPIS. A generic name proposed
by Dr. R,. Kner, and accepted by
Mr. Salter, for certain species of
Cephalaspis, namely C. Lewisii,
and C. Lloydii.

PTERIC'HTHYS. (from Tnepvg, a wing,
and i'xQvs, a fish, Gr.) The winged
fish, an ichthyolite of the lower
old red sandstone. Hugh Miller
thus graphically describes the pte-
richthys, "on a ground of light
coloured limestone, lay the effigy
of a creature fashioned apparently
out of jet, with a body covered
with plates, two powerful-looking
arms articulated at the shoulders,
a head as entirely lost in the trunk
as that of the ray or the sun-fish,
and a long angular tail. This ich-
thyolite in my large specimens
does not much exceed seven inches
in length." Agassiz has distin-
guished nine species.

PTERO'CERES. A genus of- winged
zoophagous univalves; they are
turrited, oval, ventricose, and tuber-
culated, the spire is short, the
aperture oval, terminating in a
lengthened canal at both extremi-
ties ; the outer lip is thickened,
expanded into horn-shaped, hollow,
thickened spines with an anterior
sinus apart from the caudal canal.
Several fossil species are recorded
from the Jurassic and Cretaceous
rocks of Franco and Germany.

PTESODA'CTTLE. ) (from Tnepov, a

PTERODA'CTYLTJS. j wing, and
TvX.o?, a finger, Gr.) An extinct
genus of winged reptiles, belong-
ing to the family Iguanida. It is
found fossil in the Jura limestone
formation, in the lias at Lyme
Regis, and in the oolitic slate of
Stonesfield. "The structure of
these animals," says Buekland, "is
so exceedingly anomalous, that the
first discovered pterodactyle was
considered by one naturalist to be
a bird; by another, a species of
bat ; and by a third, a flying rep-
tile. The form of its head and
length of neck, resembled that of
birds, its wings approached to the
proportion and form of those of
bats, and its body and tail approxi-
mated to those of ordinary mam-
malia. The pterodactylus forms
an extinct genus of the order Sau-
rians, in the class of reptiles;
adapted by a peculiarity of struc-
ture to fly in the air." The ptero-
dactyles are considered by Cuvier
to rank among the most extraordi-
nary of all the extinct animals that
have come under his consideration.
Species have been discovered, of
sizes varying from that of a snipe
to that of a cormorant. They had
a short tail, an extremely long
neck, and a very large head ; their
eyes were of enormous size, appar-
ently enabling them to fly by night;
the beaks were long, like those of a
crocodile, and furnished with sixty
sharp-pointed teeth. Their most
remarkable character consisted in
the excessive elongation of the se-
cond toe of the fore-foot, which
was more than double the length
of the trunk, and, in all proba-
bility, served the purpose of sup-
porting some membrane which en-
abled the animal to fly. The fingers
terminated in long hooks, like the
curved claws of the bat. The form
and size of the foot, leg, and thigh,
show that this extraordinary ani-

P T E

[372]

P U M

mal was capable either of standing
firmly on the ground, or of perch-
ing upon the branches of trees. It
is deemed probable that the ptero-
dactyle had the power of swimming.

PTE'EOPOD. } (from Tnepov, a wing,

PTEEO'PODA. j and TTOW, a foot, Gr.)
The second order of the class
Cephalophora. A class of molluscs
possessing organs adapted for either
swimming or sailing. The genera
belonging to this class have the sac
formed by the mantle closed on
every side ; a structure rendering it
necessary that the gills should be
placed externally, as regards the
sac ; and they are found spreading
out like a pair of wings on each
side of the neck. This position of
the gills, causing them to resemble
the wings of an insect, suggested
to Cuvier the name which he
assigned to the class.

PTERO'PODOTJS. Belonging to the class
Pteropoda ; wing-footed.

PTEEYG'OTTJS. The name given by
M. Agassiz to a genus of fossil
fishes discovered in the Upper
Ludlow Rock. These singular
winged bodies have been called
Sera^hims by the Scotch quarry-
men. M. Agassiz says, "the more
I know of this creature, the more
I am tempted to believe that it was
a fish ; but how absolutely decide
upon it, when we have neither
discovered head nor tail, but only
large wings." — Murchison. Silu-
rian System.

PTILO-DI'CTTA. (from TTTI'XOV, pluma,
and SIKTVOV, rete, Gr.) The name
assigned by Mr. Lonsdale to a
genus of corals found in the Silu-
rian rocks, from the feather-like
arrangement of the middle and
lateral cells, and their net-like
union. "This fossil," says Mr.
Lonsdale, "is considered by Gold-
fuss to be ajlustra, but it is placed
by Milne Edwards among the
doubtful species of that genus. It
differs essentially from Flustra in

the thickening of the external crust.
Prom JSschwra it differs in not
having a central partition, and in
the surface of the cells not being
convex, but depressed as in Plus-
tra." For a description of the
generic characters the reader is
referred to Sir R. Murchison's
Silurian System. One species, P.
lanceslata, has been established by
Mr. Lonsdale.

PTYCHACA'NTHUS. The name of a genus
of ichthyolites of the old red sand-
stone.

PFBE'SCENCE. (from pubesco, Lat. to
grow mossy, or hairy.) The downy
substance on plants, resembling
fine silken short hairs.

PUBE' SCENT. Clothed with fine short
hairs or down.

PU'DDING-STONE. A conglomerate
composed of rounded stones im-
bedded in a paste. Pudding-stone
is distinguished from breccia by the
form of the contained pebbles : in
the latter they are sharp angular
fragments ; in the former they are
rounded nodules.

PULVINI'TES. (from pulvinus, Lat. a
cushion.) A fossil bivalve found
in the baculite limestone of Nor-
mandy.

PU'MICE. } (pumex, Lat. pomice,

PI/MICE -STONE. ) It.) The Bim-
stein of Werner : Ponce of Brong-
niart : La pierre ponce of Brochant :
Lave vitreuse pumicee of Hau'y.
A light, spongy, fibrous lava, pro-
duced by the action of gases on
trachytic and other lavas. The
island of Lipari contains a moun-
tain entirely formed of white pum-
ice : when viewed from a distance,
the appearance is that of a moun-
tain completely covered with snow;
it is called II Campo Bianco. Klap-
roth gives the analysis of a speci-
men from Lipari as follows : silex
76-5, alumine 17' 5, soda and potash
5*0, iron 1§75. Immense quanti-
ties of pumice are sometimes ejected
from volcanoes. "Werner and Kar-

PUN

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P TT K

sten have divided pumice into three
sub- species, namely, Glassy pumice,
Common pumice, and Porphyritic
pumice. Glassy pumice is dis-
tinguished from the other sub-
species by its darker colours, its
vitreous and conchoidal cross-frac-
ture, and its greater hardness and
translucency. Porphyritic pumice
is distinguished by its containing
crystals of felspar, quartz, and
mica, thus forming a sort of por-
phyry. Abich divides pumice into
two groups; the cellular being
dark green, poorer in silica and
richer in alumina, derived from
clinkstone, trachyte, or andesite;
the filamentous white, containing
more silica, and derived from tra-
chytic porphyry. — Jukes.

PU'NCTATED. (from pungo, Lat. to
prick.) Marked with small dots
or punctures ; full of small holes.

PU'NCTTJLATED. Some of the ganoid
scales of Burdie House present
surfaces similarly punctulated.—
Hugh Miller.

PtfpA. ($upat Lat.)

1. In conch ology, a genus of cy-
lindrical univalve land shells, be-
longing to the family Colimacea.

2. In entomology, the chrysalis;
one of the states of existence of
such insects as undergo metamor-
phoses.

PU'RBECK BEDS. (The Calcaire Luma-
chelle Purbeckien of Brongniart.)
A fresh-water deposit, consisting
of various kinds of limestones and
marls. The Purbeck beds consti-
tute the lowest members of the
Wealden group, lying below the
Hastings sands, and immediately
above the Portland beds. The
Purbeck limestone abounds in or-
ganic remains, and the marble is
a congeries of small fresh-water
snail-shells (paludina), intermixed
with the minute crustaceous cover-
ings of a species of cypris. The
Purbeck beds consist of many thin
strata of argillaceous limestone,

alternating with schistose marls,
and forming an aggregate of up-
wards of 300 feet in thickness.

PU'RBECK STRATA. The lowest de-
posits of the Wealden group.

PI/RPLE CO'PPER ORE. The Cuivre
pyriteux hepatique of Haiiy; the
buntkupfererz of Werner. A spe-
cies of sulphuret of copper. This
ore occurs in masses, or plates, or
disseminated; it is characterized by
its lively and variegated colours,
from which circumstance it is fre-
quently called variegated pyritous
copper.

PU'RPURA. (purpura, Lat. the shell-
fish from which purple cometh.)
A genus of marine univalves be-
longing to the family Purpurifera.
The shells of this genus are found
at depths varying to twenty-five
fathoms, and the greater number
of the species are littoral. The
Purpura is an ovate univalve, its
surface being rather rough with
spines or tubercles; aperture notch-
ed, and slightly channelled in the
lower part ; the columella naked,
flat, depressed, and terminating in
a point at the base. The animal
resembles that of a true buccinum.
The species are very numerous;
the animal secretes a purple liquor,
which was formerly used in dyeing.
Fossil and recent.

PURPURI'FERA. A family of Tracho
lipoda in Lamarck's system, com-
prising the genera Buccinum, Gas-
sidarea, Cassis, Concholesas, Do-
Hum, Eburna, Harpa, Monoceros,
Purpura, Bicinula, and Terebra.

PURPURO'IDEA. A genus of turbinated
and tubercolated univalves found
in the great oolite ; it is ventricose,
with one or more circles of spines
or tubercles : the aperture is large
ovate, the base widely notched, the
columella is smooth, rounded and
curves upwards at its base : three
species are found at Minchinhamp-
ton. — Lycett.

PUT

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P Y K

PFTA'MEN. (putamen, Lat. a shell of
a nut.) In botany, another name
for the endocarp, stone, or shell of
certain fruits.

PJCNODO'NTID^. According to some
naturalists, a family of extinct
fishes of the order Ganoidea Rhom-
bifera. This family comprises
many genera, namely, Pycnodus,
Gyrodus, Phyllodus, &c., &c.

PY'CITODONTS. (from TTVKVO-S, thick,
and 080 v?, a tooth, Gr.) Thick-
toothed fishes. An extinct family
of fishes which prevailed exten-
sively during the middle ages of
geological history. Their leading
character consists in a peculiar
armature of all parts of the mouth
with a pavement of thick, round,
and flat teeth, the remains of which,
under the name of bufonites, occur
most abundantly throughout the
oolite formation.

PYCNO'DTJS TRIGONUS. A genus of
thick-toothed fishes, belonging to
the family of Pycnodonts.

PY'CNITE. A mineral of a yellowish-
white colour, found principally at
Altenberg, in Saxony.

PYBA'LLOLITE. (from Trvp, fire, aXXos,
and X/009, a stone, Gr., in allusion
to its change of colour when ex-
posed to the action of fire.) An
earthy mineral discovered by Nor-
denskiold in the lime quarries, at
Pargas, in Finland. It is a tri-
silicate of magnesia mixed with
hydrate of the same. Its analysis,
according to Nordenskiold, gives
silica 56-62, magnesia 23-28, alu-
mina 3'41, lime 5*56, proxide of
iron 0'99, protoxide of manganese
0'99, water 3'58. Specific gravity,
2'55; hardness, 3*5. It occurs mas-
sive, and crystallized in flat rhombic
prisms, much resembling those of
tremolite, and is divisible parallel
to the planes of a rhombic prism :
the prisms are generally above an
inch in length, have occasionally
a greenish tinge, but by exposure
become of a pale yellow, and are

then soft and friable. — Phillips.

PY'RAMTD. (w^o/us, Gr., from irvp,
fire ; pyr amide, Fr. pyr amide, It.)
The name given to a certain figure,
from its resembling the shape of
flame. A solid figure, whose base
is a polygon, and whose sides are
plain triangles, their several points
meeting in one. In mineralogy,
a pyramid is formed by the meeting
of three or more planes at a point,
which is termed the apex, each
plane being bounded by edges ;
considered separately, a pyramid
is supposed to have a base, which
is the case in regard to the tetra-
hedron; but in respect of such
other forms, it is only imaginary,
as in the instance of the octahedron,
which is often termed a double
four-sided pyramid; and also the
dodecahedron with triangular faces,
which is frequently denominated
a double-sided pyramid.

PYBAMIDE'LLA. A genus of marine
univalves, belonging to the family
Plicacea. It is found on coral reefs,
sands, and sandy mud, at depths
varying to twelve fathoms. The
pyramidella is a turriculated uni-
valve ; opening entire and semi-
oval; columella projecting, with
three transverse folds, and perfo-
rated at its end.

PY'RENAITE. | A greyish -black dode-

PY'BENEITE. ) cahedral, opaque va-
riety of dodecahedral garnet. It
consists of silica 43, alumina 16,
lime 20, oxide of iron 16, water 4.
It is found in the Trench Pyrenees,
from which circumstance it has
obtained its name, in limestone.

PY'RGOM. (Called also Fassaite.) An
earthy mineral of a dingy green
colour ; a variety of augite.

PYRI'TES. (irupiTijs, Gr. pyrites, Lat.
pyrite, Fr.) Sulphuret of iron.
The fersulfure of Haiiy, who has
described sixteen modifications of
the primitive form of its crystals.
The colour of pyrites is usually
bronze yellow, passing to brass

P Y E

[375 ]

P Y B

yellow, and sometimes to brown.
It possesses the hardness of quartz,
striking fire with steel, and emitting
an odour of sulphur. Specific
gravity from 4*10 to 4'80. Before
the blow-pipe it exhales a strong
odour of sulphur, and yields a
brownish. globule. It is composed
of sulphur and iron; iron 47-85,
sulphur 52 '15. It occurs in almost
every rock, stratified or unstratified.
The shining yellow streaks so com-
mon in our coals afford familiar
examples of pyrites.

PYRI'TIFEROTJS. Yielding or contain-
ing pyrites (sulphuret of iron).
"These beds are underlaid by
sandy pyritiferous shale." — Murchi-
son.

PY'ROCHLORE. The pyrochlor of Wer-
ner. Octahedral titanium ore.

PYRO'GENOTJS. (from Trvp, fire, and
ryej/i/aw, to produce, Gr.) Pro-
duced by fire, as rocks of igneous
origin.

PYROLU'SITE. Another name for the
common ore of manganese, as pris-
matic manganese ore.

PYRO'METER. (from irvpt fire, and
/merpov, measure, Gr.) An instru-
ment for measuring intense degrees
of heat. The most celebrated
pyrometer is that invented by Mr.
Wedgewood, the extremity of his
scale reaching to 240° Wedgewood,
or 32277° Fahrenheit.

PYRO'PE. (from TrvpwTros, Gr. pyropas,
Lat.) The Pyrop of Werner;
Grenat, rouge de feu, granuliforme,
of Haiiy ; Grenat pyrope of Brong-
niart ; Bohemian garnet of some
authors. A deep blood-red variety
of dodecahedral garnet. It consists
of silica 40-0, alumina 27'6, oxide
of iron 16'0, magnesia lO'O, lime
3-5, chromic acid 2-6, oxide of
manganese 0*3. It occurs in small
masses or grains. It is generally
transparent, with a splendent, vi-
treous, conchoidal fracture. Specific
gravity from 3-7 to 3 §9. It refracts
double, and is sufficiently hard to

scratch glass. Its fine blood- red
colour is supposed to be owing to
the presence of chromic acid. It
is found imbedded in serpentine,
wacke, and trap-tuff in Ceylon,
and different parts of Germany. It
is also found in some alluvial soils,
accompanied by sapphires and
hyacinths. As a gem it is highly
prized.

PYRO'PHORTJS. (from 7rvp, fire, and
and 0o/)09, bearing, Gr. pyrophore,
Fr.) A substance which has the
property of igniting merely on ex-
posure to the air. It is an artificial
production, and may be variously
prepared. M. Gay Lussac formed
a pyrophorus of one part of lamp-
black and two parts of sulphate of
potash.

PYROPHY'LLITE. An earthy mineral,
described by Hermann of Moscow,
occurring in the Ural mountains.
It is of a light green colour, has a
pearly lustre, and may be divided
into thin and transparent laminae.
It is found in fibrous radiating
masses, and small elongated prisms,
sometimes with terminations, whose
form is not however ascertained.

PYROPHY'SALITE. A variety of topaz.
The Pyrophysalith of Hisenger.
This mineral which some authors
consider to be intermediate between
topaz and schorlite occurs princi-
pally at Finbo, near Fahlun, in
Sweden. It is of a greenish- white
and mountain green colour, trans-
lucid or opaque, and sometimes
prismatic. On burning coals it
phosphoresces, in consequence of
the fluate of lime with which it is
mixed ; from this property it has
obtained its name, which is derived
from the Greek. It occurs massive
and crystallised, and may be regarded
as a coarse opaque variety of topaz.
Specific gravity 3-451. It scratches
glass, but is itself scratched by
quartz. It contains alumina,
silica, fluoric acid, and a trace of
lime and iron.

P Y E

[ 376]

QUA

PTBOSO'MA. (from irvp, fire, and
aw pa, a body, Gr.) From the
phosphorescent character which
they possess they have obtained
their name. A floating polyp,
differing from the coral in being
locomotive. Peron observed that
when irritated its phosphorescence
was augmented.

PYEOXE'NE. (from rrvp, fire, and £eVos,
a stranger, Gr.) The name given
by Haiiy and Brongniart to augite.

PI'EITLA. (frompyrum, a pear, Lat.)
A genus of marine univalves, be-

longing to the family Canalifera.
Eecent pyrulsB are found at depths
varying to nine fathoms, in mud
and sand sand. The pyrula is a
somewhat pyriform univalve, swell-
ing in the upper part, with no
variciform sutures, caudated, cana-
liculated, spire short, aperture
wide, outer lip thin, and not slit,
columella smooth. Six species
have been found fossil by Lamarck.
Pyrula3 are also found in the
London clay, and in the Bognor
sandstone.

Q

QUA'DEATE. (quadratus^at.) Square;
having four equal and parallel
sides.

QUADEICA'PSULAE. In botany, having
four capsules to a flower.

QTJADBIDE'NTATE. Four- toothed.

QTTADBILO'BATE. (from quatuor, four,
and lolus, a lobe, Lat.) A term
applied in botany to a part having
four lobes ; as a quadrilobate leaf.

QUADBILO'CTTLAB. (from quatuor, four,
and loculus, a cell, Lat.) Four-
celled ; having four cells.

QUADBIPHY'LLOTJS. (from qmtuor,
four, Lat. and 0vX\oi/, a leaf, Gr.)
In botany, having four leaves;
four-leaved.

QIJADBIPLI'CATED. (from quatuor ', four,
and plica, a fold, Lat.) A term in
eonchology ; having four plaits or
folds.

QUADEIVA'LVULAB. (from quatuor,
four, and valva, a valve, Lat.) A
term in botany ; having four
valves.

QUADETJ'MANA. (from quatuor, four,
and manus, a hand, Lat.) The
second order of Mammalia, in-
cluding the monkeys, lemurs, and
onisites. All the animals of this
order have the toes of the hind feet

free and opposable to the others,
and all the toes are as long and
flexible as the fingers. The great
character which distinguishes the
members of this order is the pos-
sessing a moveable thumb on their
lower extremities opposed to the
fingers.

QUADBTJ'MANOUS. Having four hands ;
four-handed.

QUA-QTJA-VE'BSAL. (quaqud, Lat.) on
every side, and versus, inclined,
Lat.) Inclined towards every
side ; facing all ways : a term
applied to the dip of a bed which
is inclined, facing all sides.

QUABTZ. (quarz, Germ, quartz, Fr.
mot emprunte de VAllemand. The
meaning of the word quartz does
not appear to be known.) Silex in
its purest form. Quartz is a
hydrate of silicon, or silex with
some water of crystallization ; it is
a compound of a metallic basis,
silicium, and oxygen. The usual
colours of common quartz are white
and grey. Quartz is found in
every variety of form, although in
its composition it varies but
slightly. When crystallised, it
usually occurs in six-sided prisms,

QUA

[ 377 ]

QUA

terminated by pyramidal points ;
but it also occurs in many deriva-
tive forms, its primitive being a
rhomboid. The primitive crystal
of quartz, says Phillips, is con-
sidered to be an an obtuse rhomboid,
of which the angles are given by
Haiiy in his Tableau Comparatif,
as being 94° 24' and 85° 36'. A
minute examination of several
specimens afforded perfect coinci-
dences of 94° 15' on the one angle,
and 85° 45' on the other, the
former differs from that given by
Haiiy, in being 9' less; the latter
in being 9' more. It scratches
glass, of which it is an essential
ingredient ; it gives sparks with
steel in great abundance. Hard-
ness = 7. Specific gravity = 2-5,
to 2 %7. Its lustre ranges from
splendent to glimmering, and is
vitreous. Fracture conchoidal.
Brittle, and easily frangible. It
exhibits double refraction, which
must be observed by viewing an
object through one face of the
pyramid and the opposite side of
the prism. It is infusible before
the blow -pipe, even when the flame
is excited by oxygen. Before the
compound blow-pipe a fragment of
rock crystal fuses instantly into a
white glass. Quartz is very gene-
rally distributed, and,, as far as our
knowledge extends at present,
appears to be the most abundant
mineral in nature. It occurs in
every rock, from granite to the
newest secondary formation ; it is
found in every district of the globe.
"When mixed with alkalies quartz
melts easily, and forms glass. It
is not acted upon by any acid but
the fluoric. Quartz often encloses,
or is mixed up with, foreign sub-
stances, from which circumstance
it assumes great varieties of colour.
Many of the precious stones consist
of simple quartz combined with
some colouring matter. Among
these we may place the amethyst,

cats' -eye, opal, Bristol diamond,
Scotch topaz, &c. Professor Jame-
son divides quartz into six sub-
species, namely amethyst, rock
crystal, "rose or milk quartz,
common quartz, prase, and cats3-
eye. Quartz exists in veins inter-
secting mountains, and it some-
times forms large beds, and even
entire mountains, which are com-
posed of this mineral in grains
united without a cement, called
granular quartz. Combined with
alumine and iron, quartz loses its
translucency and passes into jasper.
When rubbed, quartz yields a
peculiar odour, and a phosphores-
cent li}*ht. Quartz is a constituent
of granite.

QFA'RTZOSE. } Containing quartz; com-
QUA'RTZY. j posed of quartz ; re-
sembling quartz ; having the
properties of quartz.
QTJAET'ZOSE CONGLOMERATE. | The
OLD RED CONGLOMERATE. j name
given to the upper division of the
]N"ew Eed System of Murchison.
When the coverings of turf or bog
are removed from the old red sand-
stone, "a conglomerate," says Sir
E. Murchison, "composed of peb-
bles of white quartz in a red matrix,
forms the upper member of the
old red sandstone, or substratum
of the carboniferous limestone."
QUARTZ ROCK. ) A compact, fine-grain-
QUART'ZITE. J ed but distinctly
granular rock, very hard, frequently
brittle, and often so divided by
joints as to split in all directions
into small angular but more or less
cuboidal fragments. — Juices.
QUATE'RNART. (quaternarius, Lat.
quaternaire, Pr.) Consisting of
four ; the number four. In
geology, a term applied to the
upper tertiary strata, or those
which are supposed to be of later
formation than any of the strata in
the Paris or London basins. The
faluns, or marls of Tourraine and
the Loire, are quaternary formations.

2 c

Q U I

[ 378 ]

HAD

A group of rocks more recent than
the Pleistocene, and by some
authors called " Post-pleiocene,"
in which all the fossil shells are
still found living on the globe,
though not always in the immediate
neighbourhood of the places where
they are found fossil. The quater-
nary, or Post-pleiocene formations
consist of irregular deposits of clay,
sand, and gravel, with which, in
many cases, are associated huge
blocks of rock, that have been
transported sometimes from vast
distances.

QUI'CKLIME. This may be obtained
by exposing chalk, limestone, or
any calcareous substance, for a
length of time, to a full red heat,
whereby the carbonic acid and the
water, which were previously in
combination, are expelled.

QUI'NATE. In botany, applied to
compound leaves when composed
of five leaflets.

QUINQTTA'NGULAR. (from quinque, five,
and angulus, an angle, Lat.)
Having five corners or angles.

QUINQUECA'PSULAR. (from quinque,
five, and capsula, a capsule, Lat.)
In botany, applied to a flower
having five capsules.

QUINQUEDE'NTATE. (from quinque,
five, and dens, a tooth, Lat.) Five-
toothed.

QTJINQUEFO'LIATED. (from quinque,
five, and folium, a leaf, Lat.)
Having live leaves.

QUINQUELO'BATE. | (from quinque, five,

QTJINQUELO'BED. ) and lobus, a lobe,
Lat.) In botany, applied to parts
which are divided to the middle
into five distinct parts or lobes.

QUINQUELO'CTTLAII. (from quinque, five,
and loculus, a cell, Lat.) Five-
celled ; having five cells.

QUINQTJEVA'LVTJLAR. (from quinque,
five, and valves, doors or valves,
Lat.) Having five valves.

KACE'ME. (racemus, Lat. a bunch of
berries.) A term used in botany
to express a kind of inflorescence,
when all the buds of a newly-formed
axis unfold into flowers, each having
stalk ; a raceme consists of nume- a
rous flowers, rather distant, each
on its own proper stalk, and all
connected together by one common
peduncle.

EADIA'TA. The name given to the
fourth great division of the animal
kingdom, in consequence of the
radiated form of the body which
is so apparent in some of the classes
which compose it. This division
comprises five classes, namely,
Echinoderma, Acalepha, Polypi-
phera, Poriphera, and Polygastrica.
The radiata are amongst the most

frequent organic remains in the tran-
sition strata, and they presentnume-
rous forms of great beauty. Eadiata
have also been called zoophyta.
They form the lowest division of the
animal kingdom, having skeletons
as various as the forms of the
animals. " The muscular system,
so essential to all the voluntary
and involuntary movements of the
higher classes, entirely disappears
in the class of radiated animals,
and with it every trace of nervous
system, which we are apt to suppose
essentially connected with all the
motions and functions of animals.
In the majority of radiated animals
the blood-vessels also cease to exist,
and with them all circulating
motion of the blood. "

RAD

[ 379 ] BAM

" In the lowest tribes of animals
the internal organization relates
almost solely to digestion, and the
food consists almost entirely of
the simplest forms of animal
matter. The alimentary canal has
often but one orifice, it is seldom
provided with masticating organs,
and scarcely a trace of any glandu-
lar organ is yet observed to assist
in the process of assimilation." —
Prof. Grant.

BA'DIATE. In botany, a corolla con-
sisting of a disk, in which the
corollets are tubular and regular,
and of a ray, in which the florets
are irregular.

BA'DIATED. (radiatus, Lat.)

1 . Adorned with rays.

2. Belonging to the division Had iata.

3. In mineralogy, when the fibres
are broad and flat, and diverging
as from a centre.

BA'DIATED IRON PYRI'TES. A variety
of sulphuret of iron of a pale bronze
yellow, more or less inclining to
steel-grey, or to brass-yellow.
When its form is spherical, the
fibres diverge from the centre ;
when nearly cylindrical, from the
axis. Its constituents are iron
46-03, sulphur 53'97. It occurs
more particularly in the chalk
deposit.

BA'DIATED QUA'RTZ. A variety of
common quartz occurring in masses
having a crystalline structure and
composed of imperfect prisms,
closely applied to each other, and
sometimes terminating in pyramids
at the surface.

RA'DICATED. (radicatus, Lat.) In
conchology, when the shell is fixed
by the base, or by a byssus, to
some other body.

BA'DICAL. (from radix, Lat. a root.)
Primitive ; original. In botany,
radical leaves are such as spring
from the root ; the dandelion is a
familiar example.

BA'DICLE. (radicula, a little root,

from radix, Lat. radicule, Fr.) In
botany, that part of the embryo
which grows downwards and be-
comes the root. The primary ob-
ject of vegetable structures appears
to be the establishment of the
functions of nutrition; and we
find that while the plumule, burst-
ing from its enveloping capsule,
proceeds to extend itself vertically
upwards, at the same time, slender
filaments, or radicles, shoot out
below to form the roots.

BA'DII VECTO'RES. Imaginary lines
joining the centre of the sun and
the centre of a planet or comet,
or the centres of a planet and its
satellite.

RADIOLI'TES. A genus of irregular
inequivalved fossil shells obtained
from that part of the Pyrenees
which is named Les Corbieres.
They are striated externally. The
inferior valve is in the form of a
reversed cone ; the superior valve
convex. They have neither hinge
nor cartilage.

BA'DITTS. (radius, Lat.)

1. The semi- diameter of a circle.
The mean radius of the earth is
intermediate between the distances
of the centre of the earth from the
pole and from the equator.

2. One of the bones of the fore-
arm, or that part of the upper
extremity which extends from the
elbow to the wrist : the fore-arm
contains two bones, the radius and
the ulna.

RAGG. | Called also Bowley ragg,
BA'GSTONE. j or Dudley basalt. A
fusible silicious stone, of a dark
grey colour, occurring near Dudley.
BA'MOSE. | (from ramus, a branch,
BA'MOUS. j Lat.) Branched ; full
of branches. Applied also to flowers
growing on the branches ; to pedun-
cles proceeding from a branch ;
and also to leaves growing on
branches when they differ from
those on the stems. Minerals

E A

[ 380 ]

EEC

having a branched appearance are
described as ramose.

EANE'LLA. A genus of marine uni-
valves, belonging to the family
Canalifera. E-ecent ranellae are
found principally in the Indian
seas, at depths varying to eleven
fathoms. Some fossil species have
been discovered in the London clay.

EAPTO'JJES. The first order of the
class Aves, or birds : this order
comprises the eagle, hawk, vulture,
and owl.

EAPTO'BIOUS. (from rapio, Lat. to
snatch.)

1. The name given to animals
which dart upon and seize their
prey.

2. The name given to certain parts
of insects. The legs are called
pedes ; when adapted to the seizing
of prey, they are called pedes rap-
torii, not arms.

EA'VIN. ) (ravin, Fr.) A deep, hol-
EA'VINE. ) low, narrow excavation
formed by the force of running
water. The French use the two
words ravin and ravine in different
significations. The word ravin is
used to express a place which has
been hollowed out by a stream of
running water, as "passer un ravin
profond" Ravine is employed to
denote a torrent of water, " espece
de torrent forme d'eaux qui torn-
bent subitement et impetueusement
des montagnes, ou d'autres lieux
eleves, apres quelquegrande pluie."
Sometimes, however, ravine is used
to signify the place worn by the
torrent.

EAT. (from raja, Lat. raie, Fr.) A
sea fish. The rays form a genus
of the order Chondropterygii ; they
may be known by their flattened
body, which is in the form of a
disk, from the union of the body
with the very broad and fleshy
pectorals, which are joined to each
other before or on to the snout, and
which extend behind the two sides
of the abdomen as far as the base

of the ventrals. The rays have no
ribs. The phalanges of the carpus
are very numerous, and each is
subdivided into several pieces by
regular articulations ; they are ar-
ranged close to one another in one
plane, and form an effectual base
of support to the integument which
covers them. Both the anterior
and posterior extremities are sup-
ported by arches of bones, forming
a sort of belt. In this genus are in-
cluded the skate, torpedo, and sting-
ray. Kirby, quoting from Lacepede,
says, an individual of a species of this
tribe, called by the sailors the sea-
devil, taken at Barbadoes, was so
large, as to require seven pairs of
oxen to draw it on shore ; he very
judiciously, however, adds two
notes of admiration to this marvel-
lous story. Fossil rays are abun-
dant throughout the tertiary for-
mation , they occur also in the
Jurassic limestone.

EAT. 1. A name given to the fins
of certain fishes. 2. In botany,
the florets composing the margin
of a compound flower.

EE'ALGAR. (realgar, Fr.) Eed sul-
phuret of arsenic. Arsenic com-
bined with sulphur forms realgar
and orpiment, which are found as
natural ores; the realgar is of a
beautiful and variable red. Eeal-
gar is a bi-sulphuret of arsenic,
consisting of arsenic 69, sulphur
31. Specific gravity 3-27. It
occurs in regular crystals, in com-
pact masses, in concretions, or in
crusts, which are sometimes earthy.
Before the blow-pipe it melts
easily, burns with a blue flame and
garlic smell, and soon evaporates.
^Nitric acid deprives it of its colour.
It occurs in veins in primary,
transition, secondary, and volcanic
rocks; in Sicily, Germany, America,
and other parts.

EE'CENT FOEMA'TION. Any formation,
whether igneous or aqueous, which
can be proved to be of a date

EEC

[381 ]

B E F

posterior to the introduction of
man is called recent.

EE'CENT PE'RIOD. That period of
time commencing with the intro-
duction of man upon this earth.

BECE'PTACLE. (receptaculum, Lat.) In
botany, the basis or point, upon
which all the parts of the fructifica-
tion rest. The receptacle is distin-
guished into receptaculum proprium,
or receptacle appertaining to one
fructification only; and receptaculum
commune, or common receptacle,
connecting several distinct fructifi-
cations.

BECLI'NED. In botany, applied to
leaves when the point is lower
than the base ; also to stems when
curved towards the ground.

BED CO'RAL. A branched zoophyte,
somewhat resembling in miniature
a tree deprived of its leaves and
twigs. It seldom exceeds one foot
in height, and is attached to the
rocks by a broad expansion or base.
It consists of a bright red, stony
axis, invested with a fleshy, or
gelatinous substance of a pale blue
colour, which is studded over with
stellular polypi.

BED CRAG. The Crag of Suffolk con-
sists of two groups, the Bed Crag
and the Coralline Crag. The Bed
Crag, which is the later formation,
is composed of red quartzose sand,
and accumulations of rolled shells.

BED MARL. Another name for the
new red sandstone,

BED OR VARIEGATED MARLS. The

uppermost division of the red
sandstone group. The Marnes
Irisees of the French, the Keuper,
Bunte Mergel of the German geol-
ogists.

BED SNOW. See Protococcus Nivalis.

BE'DDLE. The roethel of Werner;
the crayon rouge of Brochant ; the
argile ocreuse rouge graphique of
Haiiy. Bed chalk; a species of
argillaceous iron-stone ore. The
best specimens are brought from
Germany. It occurs in opaque

masses, having a compact texture.
In hardness, it differs but little
from chalk. It is dry, and rough
to the touch, adhering to the tongue,
and yielding an argillaceous odour.
Specific gravity from 3-10 to 31 90.

BED SANDSTONE GROUP. This group
is placed below the oolitic group,
and above the carboniferous group ;
and in Sir H. De la Beche's table
constitutes the sixth group of the
superior stratified or fossiliferous
rocks. The red sandstone group
comprises — 1. The variegated or
red marl; 2. The muschelkalk ;
3. The red sandstone ; 4. The
zechstein or magnesian limestone ;
5. The red conglomerate.

BEEF, (riff, Germ.) A range of
rocks lying generally near the
surface of the water.

BEFLEC'TING GONIO'METER. An in-
strument invented by Wollaston,
and improved by Sang, for mea-
suring the angles of crystals.
By the reflecting goniometer the
smallest crystals may be accurately
measured, for, provided the surface
be perfect and brilliant, the 100th
part of an inch in length and
breadth will suffice.

BEFLE'CTION. The act of throwing
back; the act of bending back;
that which is reflected. By the
laws of optics, the angle of reflection
is equal to that of incidence, what-
ever the reflecting surface may be,
and however obliquely the light
may fall upon it.

BEFRA'CTION. (refraction, Fr. refra-
zi6ne, It.) The incurvation, or
change of determination in the
body moved, which happens to it
whilst it enters or penetrates any
medium ; in dioptricks, it is the
variation of a ray of light from that
right line, which it would have
passed on in, had not the density
of the medium turned it aside.
"When light passes through a drop
of water or a piece of glass, it
obviously suffers some change in

B E F

[382 J

B E P

its direction. These bodies have
therefore exercised some action, or
produced some change upon the
light, during its progress through
them. The power which thus bends
or changes the direction of a ray of
light is called refraction, and the
amount of this refraction varies
with the nature of the body. All
the celestial bodies appear to be
more elevated than they really are ;
because the rays of light moving
through the atmosphere in straight
lines, are continually inflected to-
wards the earth. Light passing
obliquely out of a rare into a
denser medium, as from vacuum
into air, or from air into water, is
bent or refracted from its course
towards a perpendicular to that
point of the denser surface where
the light enters it. The denser the
medium the more the ray is bent.

BEFBA'CTION DOUBLE. When a ray
of light passes obliquely from one
medium to another of a different
density, it is refracted, or bent
from its original direction. Still,
the image of any object, seen
through a refracting medium, usual-
ly appears single. There are, how-
ever, some transparent minerals,
which have the remarkable pro-
perty of causing objects to appear
double ; that is, they present two
images of any object seen through
them. In this case it is evident
that the ray must be divided into
two portions after entering the
refracting medium, and that each
portion presents an image of the
object. This is a distinctive cha*
racter of very considerable value in
some minerals, not depending on
any accidental circumstances, but
on the nature of the mineral.
Double refraction is exhibited most
strikingly in Iceland spar.

BEFEA'CTOEY. A term applied to
minerals when they possesss the
property of resisting the application
of strong heat ; it is also used for

such as are so tough as to with-
stand repeated blows.

BEFEIGEEA'TION. (refrigeration, Fr.)
The act of cooling down ; the state
of being cooled

It is the opinion of some geolo-
gists that the whole of this planet
was formerly in an incandescent
state, and that the process of refri-
geration has been constantly pro-
ceeding ; that the crust of the
earth has cooled down to its present
temperature, but that the centre of
the earth is still a molten mass.
Professor Whewel, speaking of
Fourier's arguments on the subject,
says, " it results from Fourier's
analysis that at a depth of twelve
or eighteen miles the earth may be
actually incandescent, and yet that
the effect of this fervent mass upon
the temperature at the surface may
be a scarcely perceptible fraction of
a degree. The slowness with which
any heating or cooling effect would
take place through a solid crust is
much greater than might be sup-
posed. If the earth below twelve
leagues depth were replaced by a
globe of a temperature five hundred
times greater than that of boiling
water, 200,000 years would be
required to increase the temperature
of the surface one degree."

BE'NIFOBM. (from ren, a kidney, and
forma, form, Lat.) Kidney- shaped.

BE'PTILE. (reptilis, Lat. reptile, Fr.
rett'ile, It.) A vertebrated, cold-
blooded, animal. The body covered
with a shell, or with scales, or
entirely naked. Possessing neither
hair, mammaB, feathers, nor radi-
ated fins; breathing through the
mouth and nose by means of lungs ;
oviparous, but never hatching its
eggs, and amphibious.

BEPTI'LIA. Beptiles form the third
class of vertebrated animals, which
is subdivided into four orders, name-
ly, Chelonia, or tortoises, Sauria,
or lizards, Ophidia, or serpents,
and Batrachia, or frogs. Beptilia

REP

[ 383

RET

have red and cold blood, with true
lungs ; they are oviparous ; the
heart is trilocular, that is possesses
three cavities, namely, two auricles
and one ventricle. The brain of
reptiles is characterized by the
position of the thalami behind the
hemispheres ; neither is there any
arbor vitae in the cerebellum. Some
naturalists divide the class reptilia
into seven orders, namely, Chelonia,
Crocodilia, Lacertilia, Ophidia,
Dtnosauria, ~Enaliosauria, and J*te~
rodactylia, the three last being ex-
tinct, and found fossil only.

REPU'LSION. (repulsion. Fr.) That
property possessed by bodies which
causes their particles to recede from
one another, or to avoid coming in
contact. In air and in liquids, the
most perfect freedom of motion of
the parts among each other subsists,
and from this, and other considera-
tions, it has been concluded that
the several parts do not touch, but
are kept asunder at determinate
distances from each other, by the
constant action of the two forces of
attraction and repulsion, which are
supposed to balance and counteract
each other.

RE'SIN. (resina, Lat. resine, Fr.)
Called also rosin. A yellowish-
white coloured substance, which
exudes from many trees, more
particularly the different species of
fir. It is somewhat transparent,
is hard and brittle, of a disagreeable
taste, and may be collected in con-
siderable quantities. Resin may
be distinguished from other sub-
stances by the following properties.
It is more or less concrete, and
possesses a certain degree of trans-
parency. Its taste is sometimes
hot and disagreeable, but not un-
frequently it is tasteless, or nearly
so. Colour generally between pale
yellow and brown. Specific gravity
from 1-0 to 1.3. It is electric and
a non-conductor of electricity. It
is insoluble in water, and by this

may be distinguished, as well as
separated from gum. It is soluble
in alcohol, ether, and in the volatile
oils. There is scarcely a plant
which does not contain some kind
of resin.

RESPIEA'TION. (respiratio,~La,i.} The
function of breathing; the act of
inhaling air into and exhaling it
from the lungs. Respiration con-
sists of two parts, inspiration,
which, in a healthy condition,
takes place about twenty-six times
in a minute, thirteen cubic inches
of air being the average quantity
taken in at each inspiration ; and
expiration, which alternates with
inspiration. It is by respiration
that the blood becomes freed of its
carbon and, at the same time,
obtains fresh supplies of oxygen.

REST/PI^ATE. (resupinatus^ Lat.) In
botany, a term applied to leaves,
when the under surface is turned
upwards.

RE'TE MUCO'SUM. (from rete, a net,
and mucosum, mucous, Lat.) A

• tissue lying immediately under the
epidermis, or scarfskin, and above
the eutis vera, or true skin. The
colour of negroes depends upon a
black pigment, situated in this
substance.

RETEPO'EA.. The name given by
Lamarck to a genus of fossil corals.

RE'TINA. (from rete, a net, Lat.)
The net-like expansion of the optic
nerve placed at the back of the
eye, and which has been called one
of the membranes of that organ.
Tli3 retina is an exceedingly thin
and delicate layer of nervous mat-
ter, supported by a fine membrane.
]STo nerve but the optic nerve, and
no part of that nerve but the retina,
is capable of giving rise to the
sensation of light.

RE'TINASPHALTTJM. A sub-species of
bitumen. An opaque, ochre-yellow,
and brittle substance found in
Bovey coal and fossil wood. Frac-
ture vitreous, and imperfectly con-

K E T

[384]

B H 0

choidal. Specific gravity 1-13.
It consists of resin 55, asphaltum
41, earthy matter 3.

BETEOELEC'TED. (from retro, back,
au&jlecto, to bend, Lat.) Bent in
different directions, usually in a
distorted manner.

BETEOMI'NGENTS. In zoology, a class
of animals, whose characteristic is,
that they void their urine back-
wards.

BETTJ'SE. (retusus, Lat. blunted.)

1. In conchology, a shell ending in
an obtuse sinus is termed a retme
shell ; bluntly notched.

2. In botany, leaves are called
retuse, when ending in a broad
shallow notch, or sinus.

3. In entomology, when the ter-
minal margin has an obtuse im-
pression.

BEVE'ESED. (reversus> Lat.) Turned
upside down ; turned side for side.
1. In conchology, a reversed shell
is one, the volutions of which are
the reverse way of the common
corkscrew.

*2. In botany, when the upper lip >
of the corolla is larger and more
expanded than the lower.

BE' VOLUTE. (revolutus, Lat.) In
botany, applied to leaves, when
the margins are rolled backwards
towards the under surface.

BE'YGATE STONE. } (So named

BE'YGATE FIEE-STONE. j from ha-
ving been formerly quarried almost
exclusively at, or in the neighbour-
hood of, Beygate, in Surrey. Web-
ster says that Beygate stone is
identical with the green sandstone.
The Reygate stone is situated
below the chalk marl and above
the ferruginous sand. It is now
procured principally at Merstham,
three miles from Reygate.

BHACHEOSATJ'ETJS. A fossil saurian of
the lias and oolite,

BHINO'CEEOS. (ptvoicepws, Gr. from
plv, a nose, and Kepa<s, a horn.) A
genus of thick-skinned mammalia
included by Cuvier in the family

Pachydermata Ordinaria. The
rhinoceros is found, at the present
day, in India, Java, Africa, and
Sumatra. It is a large animal,
having three toes, but the feet not
cloven. The bones of the nose
support a solid horn in two species
of this genus ; but the other
species possess two horns.

Fossil remains of the rhinoceros
are found in Siberia and Germany.
The entire carcass of a fossil rhi-
noceros was discovered, in frozen
sand, on the banks of the Wilaji,
in Siberia. Bones and teeth of the
rhinoceros are found in this coun-
try in superficial gravel and loam.

BHIPI'PTEEA. A new order of insects,
established by Kirby under the
name of Strepsiptera (twisted
wings), named Bhipiptera by La-
treille, includes only two genera,
namely Stylops and Xenos. These
insects are remarkable for their
anomalous form, and the irregu-
larity of their habits. The tegmina
are fixed at the base of the anterior
legs ; they are both long and
narrow, and appear to be incapable
of protecting the wings. The
wings are large, membranous, di-
vided by longitudinal and radiating
nervures, and fold longitudinally,
after the manner of a fan.

BHIZO'MA. (pi^wfia, a root, Gr.) A
species of creeping stem which
grows under-ground.

BHIZO'PODES. A class of animals of
lower degree than the Badiata,
possessing a power of locomotion
by means of minute tentacular
filaments ; comprising the animals
whichconstruct the miliola, and some
microscopic foraminiferous shells.

BHO'DLUM. A metal of a white colour,
having a metallic lustre, brittle
and hard: specific gravity 11.
Discovered by Wollaston in 1803,
in the native ore of platinum.

BHODOCBINI'TES. (from podov, a rose,
and Kpivov, a lily, Gr. So named
from the rose-like figure of its ali-

E H 0

[_ 385 ]

E 0 C

mentary canal.) A genus of fossil
crinoidea occrring in the mountain,
limestone.

RHOMB. (/>o/*/3o<?, Gr. rhombus, Lat.)
In geometry, an oblique-angled
parallellograra, or quadrilateral
figure, whose sides are equal and
parallel, but the angles unequal,
two of the opposite sides being
obtuse, and two acute.

RHO'MBOJD. (from popfios, a rhomb,
and eTdos, form, Gr.) A figure
which has its opposite sides equal
to one another, but all its sides are
not equal, nor are its angles right
angles.

RHOMBOHE'DEON. A solid contained
by six plane surfaces, thfc opposite
planes being equal and similar
rhombs parallel to one another;
but all the planes are notnecessarily
equal or similar, nor are its angles
right angles.

RHOMBOI'DAL. Having the form of a
rhomboid.

RHOMB SPAE. Called also bitter spar,
a variety of magnesian carbonate
of lime. This variety occurs crys-
tallised, most of its crystals being
rhombs, sometimes truncated, and
sometimes with rounded edges.
Fracture foliated, the folia) having
a shining or splendent lustre, more
pearly than that of calcareous spar.
Specific gravity from 2*48 to 3.
It is generally of a greyish colour
to pale yellow, or yellowish brown.
It appears to pass by imperceptible
shades into dolomite.

RIBB'ON JAS'PEE. A variety of jasper,
presenting green, red, and yellow co-
lours, of various shades.

RIBBON AGATE. Called also Striped
Agate. A kind of agate which,
on being cut at right angles with
the layers of which it is composed,
presents alternate colours, some-
times straight, at others curved,
but always parallel with each other.
For a description see Agate.

RI'MA. In conchology, the interstice

between the valves, when the hy-
men is removed.

BI'MULA. A genus of small patelliform
shells separated from Emarginula
on account of the position of its fissure
which approaches the margin but
does not reach it. The great and
inferior oolite of Gloucester have
species. — Lycett.

RI'NGENT. (from ringo, to grin, Lat.)
In botany, applied to a monopeta-
lous corolla, the border of which
is usually divided into two lips,
which gape like the mouth of an
animal. A corolla with two lips
is called bilabiate; when these
present an appearance like the
mouth of an animal, the corolla is
called rinyent.

RINGI'CULA. A genus of fossil uni-
valves ; a species of which occurs
in the Suffolk Crag, and also at
Bordeaux, and which was formerly
attributed to Auricula.

RI'SSOA. A genus of small turrited
univalve shells, placed by Sowerby
near to the ScalariaB. The aperture
is expanded anteriorly, and the
outer lip thickened. FOU? species
are known fossil in the great and
inferior oolite of Gloucestershire,
and in the great oolite at Ancliff.
Lycett.

RO'ACH. A provincial term given to
the upper bed of the Portland oolite,
" it is," says Mantel], " a congeries
of casts of trigonise, pernae, terebrse,
ammonites, lucinaD, &c."

ROCK, (roc and roche, Fr. rocca, It.)
Rocks, and the substances they
enclose, lie beneath the superficial
accumulations, and constitute the
crust of the earth. The term
" rocks" is apt to mislead begin-
ners ; for under this title geologists
rank clay, sand, coal, and chalk, as
well as limestone, granite, slate,
and basalt, and other hard and
solid masses, to which the use of
the term is generally restricted.

The rocks of which the mineral
crust of the globe is composed are

2 D

ROC

[ 386

BOD

divided into those of aqueous and
igneous origin, from the two agents
known to us as capable of their
production. Bocks are also divided
into primary, transition, secondary,
tertiary, &c.

BOCK BTJ'TTEK. Native alum. It
occurs in the cavities or fissures of
argillaceous slate in soft masses ; it
is of a yellowish- white colour; a
little unctuous to the touch ; mas-
sive, tuberose, or stalactical. It is
mingled with clay and oxide of
iron.

BOCK CBT'STAL. Called also Moun-
tain Crystal. The Berg Crystal of
Werner. This, which is only the
most perfect variety of quartz, has,
when crystallized, received the
name of rock crystal: the same
name has been extended to coloured
crystals, when transparent. Bock
crystal is usually limpid, colour-
less, and as transparent as glass;
it is, however, occasionally met
with coloured, passing from white
into yellow, brown, red and brown-
ish black. The finest specimens
of rock crystal are found in Dau-
phine, in the Alps, in Madagascar,
&c. ; but it abounds in every coun-
try, in all parts of the world, in
chasms or clefts of the oldest rocks.
The primitive form is a rhomboid
of 94° 15' and 85° 45'; the second-
ary forms are an equiangular six-
sided prism, rather acutely acumi-
nated on both extremities by six
planes, which are set on the lateral
planes ; a double six-sided pyramid ;
an acute simple six-sided pyramid,
and acute double three- sided pyra-
mid. Splendent ; fracture perfect
conchoidal; gives double refraction
when viewed through a pyramidal
and lateral plane at the same time.
It is perfectly infusible before the
blow-pipe, and is sufficiently hard
to scratch glass. Its specific gra-
vity is from 2-5 to 2*8. By fric-
tion it exhales a peculiar odour,
and some varieties also phospho-

resce in the dark. An analysis by
Bergman gave silex 93, alumine 6,
lime 1 . Bucholz states it to con-
sist of silica 99|, with a trace of
ferruginous alumina.

BOCK WOOD. A variety of asbestus
of a brown colour ; in its general
appearance greatly resembling fos-
sil wood.

BOCK CORK. Called also Mountain
cork ; a white or grey-coloured
variety of asbestus. Its specific
gravity varies from 0-68 to 0.99 :
this, and its fibrous structure, have
obtained for it the name of cork.
Its constituents are silex 56-3,
magnesia 26-2, lime 12 '4, alumine
2, iron 31. It occurs in Prance,
Germany and some other countries.

BOCK SALT. Common salt. This is
found in vast solid masses or beds,
in different formations, but most
extensively in the new red sand-
stone formation. Although rock
salt, salt mines, and salt springs
are most frequently found to occur
in the new red sandstone formation,
(from which circumstance many
geologists have applied to it the
name of saliferous formation) yet
are they not confined to them.
The salt mines of Wieliezka and
Sicily are in tertiary formation ;
those of Cardona are in the chalk
series ; some are in the oolitic de-
posits ; and in the county of
Durham salt springs occur in the
carboniferous series.

The saliferous strata of North-
wich, form two beds of great
thickness, one being 120, the other
110 feet in thickness. The origin
of these beds does not appear, to
the present time, to be satisfactorily
understood or explained.

BODE'NT. An animal belonging to
the order Bodentia, or gnawers.

BODE'NTIA. (from rodo, Lat. to gnaw.)
The fifth order of Mammalia : call-
ed also Gnawers. The order contains
many genera, some of which are
familiar to us, namely, the squirrel,

B 0 E

[ 387 ]

EOT

the rat, the mouse, the hare, the
rabbit, &c., &c. From the charac-
ters of their teeth, which are
adapted neither for seizing nor
tearing their food, but merely to
nibble and gnaw it, they have
received their name of Rodents, or
gnawers.

HOE STONE. A name given to the
oolite, a variety of limestone, from
its being]composed of small rounded
particles, resembling the roe or
eggs of a fish.

BOMA'NZOVITE. A mineral of a brown,
brownish yellow, and blackish-
brown colour, named after Count
Bomanzoff. According to the anal-
ysis of M. Julin, it consists of
silica 41-22, lime 24- 78, alumine
24-08, oxide of iron 7'02, magnesia
and oxide of manganese 0-92.

The name given by Nordenskiold
to a variety of cinnamon-stone,
occurring at Kimito in Finland.
See Cinnamon- stone.
ROSA'CEJE. An order of plants, inclu-
ding the genera potent ilia, fragaria,
rosa, rubus, spiraea, brayera, dryas,
&c., &c. The whole order is inno-
cent.

BOSA'CEOUS. Belonging to the order
BosaceaB. Applied to polypetalous
corollas, consisting of four or more
petals, spreading like a rose.
ROSE QUARTZ. (The Quartz hyalin
rose of Haiiy.) A subspecies of
quartz of a rose-red colour, as its
name implies. This mineral occurs
massive only ; it differs from quartz
only in its colour, which colour is
attributed to the presence of man-
ganese. See Milk quartz.
ROSTELLA'EIA. A genus of marine
univalves, recent and fossil. A
slightly turretted or fusiform uni-
valve, terminating at its base in a
lengthened canal, similar to a sharp
beak- The lip whole or dentated,
and dilated with age; with a
groove contiguous to the canal. Re-
cent RostellariaB are found in the
Indian seas.

RO'STEATED. (restrains, Lat. beaked.)

1. In botany, a term applied to
plants when the fruit has a beak-
like proccess.

2. In conchology, applied to shells
having a beak-like extension of the
shell, in which the canal is situated.

BO'STKUM. (Lat.) A beak or bill ;
the beak or bill of a bird.

ROTA'LIA. A genus of microscopic
shells found in flint and in chalk.

BOTALI'TES. A genus of shells exist-
ing only in a fossil state, and found
at Grignon. The shells of this
genus are convex, conical, spiral,
multilocular univalves, slightly
radiated beneath ; aperture mar-
ginal, trigonal, and inclined down-
wards.

BOTHE TODTE LiEGE^DE. The name
given by the Germans to the lowar
beds of the new red sandstone
group.

BOT^FEEA. The first order of the
class Infusoria. "Minute, trans-
parent, soft, aquatic animals with
distinct muscular and nervous sys-
tems, provided with eyes, lateral
maxillae, an intestine with distinct
buccal and anal openings." — Prof.
Grant. The researches of Ehren-
berg show that a group, formerly
believed to belong to the class of
the most minute animalcules, pos-
sess an organization extremely
complex. Ehrenberg has called
them "rotatoria," but the term
rotifera is more generally used.
They are distinguished by their
circles of cilia, sometimes single,
sametimes double, which, through
the microscope, appear like re-
volving wheels.

The object of the rapid gyration
of this wheel or wheels is to create
a vortex in the water, whose
centre is the mouth of the ani-
mal; a little charybdis, bearing with
it all tho animalcules or molecules
that come within its sphere of
action.

ROT

[ 388 ]

BUT

BO'TTEN STONE. Another name for
Tripoli. See Tripoli.

BU'BELITE. j The Tourmaline rubel-

BU'BELLITE. j lite of Brongniart;
Tourmaline apyre of Haiiy. Bed
tourmaline. A mineral of a red
colour, of various shades; in the
form of its crystals it resembles
schorl, as well as in its power of
acquiring opposite electricities by
heat. It is translucent, semetimes
transparent. Specific gravity 307.
Its crystals are cylindrical or acicu-
lar, and aggregated in groups.
Before the blowpipe it becomes
white, but does not fuse. Its con-
stituents are silex 42-0, alumine
40 0, soda 10-0, oxides of manga-
nese and iron 7*0. In the British
Museum there is a specimen of
Bubellite, from the kingdom of
Ava, valued at £1000. Some
mineralogists deem rubellite to be
merely a variety of tourmaline, it
was however arranged as a distinct
subspecies by Karsten and Steffens.
Bubellite has also obtained the
names of Daourite and Siberite.

BTJ'BBLE. A term applied to loose
angular gravel, or a slightly com-
pacted brecciated sandstone.

BU'BY, (from rubeo, Lat. to be red,
rulis, iY. rulino, It. rulm, Germ.)
The Spinell of Werner; Spinelle
rubis of Brongniart. A transparent
red variety of rhombohedral corun-
dum. The ruby is a variety of the
same mineral genus as the sapphire,,
but differs from it in containing
rather more silex, and in being less
hard. Bubies are found in alluvial
soil in Ceylon, Pegu, and other
conntries in the East. The ruby
ranks next to the diamond in value.
When a specimen is fine, and free
from flaws, a ruby of large size
will sell for from ten to fifteen
thousand pounds.

BUD'ISTES. A family of the order
Conchifera M'onomy aria of Lamarck,
containing the genera Crania, Pis-

cina, Birostrites, Badiolites, Sphce-

rulites and Calceola. — Lycett.
BUGO'SA. The name of an extinct

order of four- starred corals, of the

class Actinozoa.
BTJGO'SE. )
Ito-wim. j

1. In concholegy, applied to shells
which are rugged and full of
wrinkles.

2. In botany, applied to leaves
when the veins are more contracted
than the disc, so that the disc rises
into little inequalities; the prim-
rose and sage afford examples.

3. In entomology, when longitu-
dudinal elevations are placed irre-
gularly on the surface, resembling
coarse wrinkles.

BTTMINA'NTIA. j The eighth order of

BU'MINANTS. j Mammalia, or those
animals that chew the cud. These
animals possess the singular pro-
perty of returning the food to the
mouth after it has been swallowed,
that it may undergo the process
of a second mastication. This
property depends upon the struc-
ture of the four stomachs which
these animals possess, the three
first being so arranged that the
food may pass from the oesophagus
into either of them. Cuvier divides
this great order into those that have
horns, and those that have none.
" Fossil ruminantia," says Pid-
geon, " are found in the depo-
sitions of many different eras. The
ruminants were clearly coeval with
the other mammifera of the ancient
world ; and they existed in a nu-
merical proportion sufficiently great
to produce an abundance of their
bones in various depositions."

BT/FCINATE. (from runcina, a saw,
Lat.) In botany, a term applied
to leaves whose edges are cut into
teeth turning backwards, like a
scythe.

BUTHE'NEUM. One of the noble
metals, its symbols being Bu.
Specific gravity 8f60.

BUT

[ 389 ]

SAL

RU'TILE. Red oxide of titanium.
The titane oxyde, of Hau'y ; titane
ruthil of Brongniart ; rutil of
"Werner; peritomes titan-erz of
Mohs. A brown, red, yellow, and
sometimes nearly velvet-black ore.
Occurs regularly crystallised, mas-
sive, disseminated, in angular
grains, and in flakes. External

lustre considerable, and sometimes
metallic. Opaque or translucent.
Scratches glass. Specific gravity
= 4-2 to 4-4. It is infusible
before the blow- pipe unless a flux be
employed. It is found in Scotland,
in the granite of Cairngorm.
RYA'KOLITE. A name given to glassy
felspar.

SACCHA'BINE LIMESTONE. "When lime-
stone is fine-grained and regular,
it resembles the crystalline struc-
ture of loaf sugar; it is hence
called saccharine limestone, or
marble.

SA'CCIIAEOID. (from ad/c^ap, sugar,
and et£os, form, Gr.) Resembling
white, loaf, or crystallized sugar.
A term applied to rocks which
have a texture resembling that of
loaf-sugar.

SA'CBUM. (Lat.) The bone which
forms the basis of the vertebral
column.

SADDLE-SHAPED STRATA. "When strata
are bent on each side of a mountain,
without being broken at the top,
they are called saddle-shaped.

SA'GENITE. Another name for rutile,
or red oxide of titanium.

SAGI'TTATE. (from sagittatus, Lat.)
Arrow-shaped.

SAH'LBANDE. } By this word is under-

SAALB'aNDE. ) stood a slip or band
interposed between the veins and
the rock which forms the body of
the mountain. The saalbande is
generally of a different nature from
the substance to which it is con-
tiguous. It is not found in all
veins, and those from which it is
absent are said to be adherent. The
term saalbande, for which we have
no corresponding scientific expres-

sion, is frequently denominated in
some of the mining districts of this
country, pasting or sticking. — Geo-
logical Transactions.

SA'HLITE. (The sahlit of Werner:
the malacolith of Brongniart.) A
variety of augite, discovered in a
silver mine at Sahla, in Sweden,
from which it takes its name. It
is of a green or greenish-grey
colour of various shades. It occurs
in straight, lamellar, and granular
concretions sometimes crystallized
with a shining, vitreous, or pearly
lustre; translucent at the edges.
It is soft to the touch, scarcely
scratches glass, and is easily
scratched by a knife. Specific
gravity 3 '2. Before the blow- pipe
it melts, with some ebullition, into
a porous glass. It consists of silica
53, magnesia 19, lime 20, alumina
3, iron and manganese 4.

SALAMA'NDEE. (<ra\a/aai'£/>a, Gr. sala-
mandra, Lat.) A genus of reptiles
belonging to the order Batrachia.
The salamander possessses the ge-
neral form of the lizard, and is
placed by LinnaBus among the
lizards ; but its characters are those
of the Batrachians. Its body is
elongated ; it has four feet, and a
long tail. When arrived at an
adult state, its respiration is per-
formed in the same manner as in

S A I

[ 390

SAL

frogs and tortoises. Aristotle and
Pliny state that if the salamander
passes through fire, the fire is
immediately extinguished, and that
it emits a milky saliva which is
depilatory. Bosc says that it emits
from its skin a milky fluid when
annoyed, and when put into the
fire, it sometimes happens that this
fluid sufficiently extinguishes it to
permit the animal to escape. This
secretion of a milky fluid appears
to be exceedingly acrid ; produces,
if applied to the tongue, a very
painful sensation ; is an excellent
depilatory, and destroys small ani-
mals. Spallanzani has discovered
-that the salamander has the power
of reproducing lost or mutilated
organs, so that if its legs or tail be
cut off, or its eyes plucked out,
these organs will, in the course of
a few months, be reproduced. It
has been found fossil.

ST. CASSIAN BEDS. A large mass of
beds occurring in the Austrian
Alps: called also Hallstatt Beds.
In these beds are found fossils of
an intermediate character between
those occurring in the paleozoic
and mesozoic rocks.

SA'LIENT A'NGLE. A projecting angle.
In a zig-zag line the upper are the
salient, a the lower the re-entering
angles. *

SALI'FEBOUS. (from sal, salt, and
fero, to bear, or produce, Lat.)
Containing salt ; yielding salt.
Thus, in geology, we have sali-
ferous deposites ; saliferous rocks ;
saliferous strata, &c. &c.

SALI'FEEOUS SYSTEM. The JSTew Red
Sandstone system of some jauthors ;
the Poikilitic system of Conybeare.
The saliferous system comprises the
new red sandstone and the mag-
nesian limestone formations. In
Germany and France there is
added to the series of strata which
we possess in this country, a
member which is called muschel-
kalk j ttiis, though extensively

developed in Germany, has never
been discovered in England. Or-
ganic remains of this system, says
Prof. Phillips, though few in
number, are exceedingly interesting
to the naturalist and geologist,
from the strong testimony they
offer of the successive changes of
the living creation, according to
the new circumstances of the land
and sea. The fossil plants, shells,
fishes, and reptiles of the saliferous
system, appear to partake both of
the character of those in the older
carboniferous, and the newer ooli-
tic, deposites. Calamites, resem-
bling those of the coal formation,
are mingled with cycadese, like
those of the oolites. .Fishes of the
genus palseoniscus are here found
for the last time ; while the re-
mains of oviparous quadrupeds, the
phytosaurus and protorosaurus, are
first discovered. Regarding it ac-
cording to its mineral characters,
it forms one great series of deposites,
which were thrown down at a
period when a decided change in
the conditions of the globe was
taking place. The manner in
which the group rests upon the
carboniferous group in England is
such as to show that the latter was
disturbed, dislocated, and partially
removed before the former was
accumulated upon it ; nevertheless,
in other parts of the European area,
there is reason for supposing that
the new red sandstone was quietly
deposited upon the carboniferous
series, no real line of separation
being established between them.
The saliferous system, commencing
with the keuper, or variegated
marls, lies immediately under the
lias, and, terminating in the red
conglomerate, rests upon the car-
boniferous series. Its depth in
some parts has been estimated at
eight or nine hundred feet.
SALIFI'ABLE. (from sal, salt, and fio,
to become, Lat.) That may become

SAL

L 391 ]

SAP

a salt by combination with some
other body ; capable of combining
with an acid to form a salt.

SA'LIVABY GLANDS. Organs which
secrete the saliva. All aniiaals
that masticate their food are pro-
vided with salivary glands, which
pour the saliva into the mouth as
near as possible to the grinding
surfaces of the teeth. Pishes and
the cetacea, performing no masti-
cation, have no salivary glands.

SALT, (sal, Lat. safe, Germ.) In
an impure state, one of the most
abundant productions of nature. It
occurs in two forms, either as a
solid mineral, or in solution, in the
waters of the ocean, and of lakes
and springs in inland districts. The
waters of the ocean contain about
one-thirtieth of their bulk in solu-
tion. The uses of salt are nume-
rous, putting aside its great im-
portance, or absolute necessity, as
a matter of food. It is employed
in glass-making, enamelling, glaz-
ing, and bleaching. It is a valuable
manure ; and is used in the making
of bread. Although the most fre-
quent position of rock-salt is in
strata of the new red sandstone
formation, yet it is not exclusively .
confined to them. The salt mines
of Wieliezka and Sicily are in ter-
tiary formations ; those of Cardona
in cretaceous; some are found in
the oolite; while others occur in
the coal formation.

SAND, (sand, Germ.) Flint or quartz
broken fine by the action of water,
but not reduced to powder. Yery
small particles of silicious matter
not cohering together, nor softened
by water.

SA'NDSTONE. An aggregate of sili-
cious grains. Any stone composed
of grains of sand agglutinated
together. The grains of sandstone
are sometimes so fine as scarcely to
be distinguished by the unaided
eye ; at others their magnitude is
equal to that of a walnut or an egg,

as in the coarse sandstones known
as conglomerates, pudding-stones,
breccias, &c. The cement which
agglutinates the silicious particles
of sandstones may be calcareous,
argillaceous, or silicious : when
silicious the sandstone sometimes
resembles quartz. Sandstones are
close, porous, and vesicular, with
every intermediate gradation, from
perfectly loose sand to the hardest
sandstone. They vary in colour,
from white to red or * brown, but
their most common colour is grey
or greyish white : sometimes their
colour is uniform, at others it is
variegated.

SA'PPAHE. A mineral first described
by Saussure. The Cyanit of Wer-
ner, and Disthene of Haiiy.

SA'PPHIEE. (from acnrfaipo's, Gr. sap-
phirus, Lat.) A precious stone,
exceeding all others in hardness
except the diamond. It occurs
crystallized, in six-sided prisms
variously terminated ; the crystals
yield readily to cleavage in one
direction, presenting a most bril-
liant surface ; cleavage fourfold ;
fracture conchoidal. It consists of
nearly pure alumina, with a little
oxide of iron, with some silex or
lime; but the sapphire contains
upwards of ninety- eight per cent,
of alumina. Its specific gravity is
from 3-70 to 4'30. It possesses
double refraction, and varies from
opaque to transparent. Its colours
are blue, red, green, white, grey,
yellow, brown, and black. There
are several varieties of the sapphire,
as the white, blue, or oriental sap-
phire, the oriental amethyst, the
oriental topaz, and the oriental
emerald. Some varieties of sap-
phire exhibit particular kinds of
opalescence, and these have obtained
the name of girasol sapphire, cha-
toyant or opalescent sapphire, and
asteria or asteriated sapphire, the
last, when cut en cabochon, presents
a silvery star of six rays, in a

SAB

[392]

S A U

direction perpendicular to the axis.
The finest sapphires are found in
alluvial soil in Ceylon and Pegu.
Lately the sapphire has been em-
ployed in the formation of small
lenses for microscopes; it is also
employed, in addition to its use as
an ornament, for jewelling the
pallets of escapements, and the
holes of wheel pivots in astrono-
mical clocks and watches. The
red sapphire is the most highly
esteemed, its value being sometimes
equal to that of a diamond of the
same size : a single stone has been
estimated at the value of one thou-
sand guineas.

SAECI'NTJLA. A genus of lamellated
polypifers, thus described by Par-
kinson. "A stony polypifer, form-
ed in a free, simple, thick mass, by
tubes united together. The tubes
numerous, cylindrical, parallel, and
vertical, accumulated in bundles
by intermediate and transverve
septa. Kadiated . lamellse within
the tubes." Sarcinula differs from
Tubipora in its tubes being lamel-
lated, and from Stylina in having
no central style.

SA'ECOCAEP. The fleshy part of cer-
tain fruits, placed between the
epicarp and the endocarp. That
part of fleshy fruits which is usually
eaten.

SA'ECOLITE. (from <ra/>£, flesh, and
X/009, stone, Gr.) A variety of
analcime, found at Mount Somma,
and obtaining its name from the
flesh colour of ts crystals, which
are cubo-octahedral.

SAED. The best specimens are brought
from Sardinia, whence its name.
A variety of chalcedony, of a deep
rich reddish-brown colour.

SA'EDONYX. (aap%6w%, Gr. sardonyx,
Lat.) The Quartz agathe sardoine
of Haiiy ; Silex sardoine of Brong-
niart. A Variety of calcedony
differing from carnelian only in
its colour, which is reddish yel-

low, or nearly orange, with oc-
casionally a tinge of brown.

SA'SSOLIN. | So called from having

SA'SSOLOE. ) been found near the
warm spring of Sasso, in Tuscany.
Native boracic acid.

SA'TIN SPAE. A fibrous variety of
calcareous spar. It is susceptible
of a fine polish, and exhibits the
lustre of satin, from which circum-
stance it has obtained its name.
Its colours are grey and pale rose-
red. Tery fine specimens are met
with in Cumberland.

SATJ'EIA. (from aavpos, a lizard, Gr.)
The second order in the class Rep-
tilia. This order, according to
Cuvier's arrangement, includes six
families, namely, Crocodilia, Lacer-
tinida, Iguanida, Geckotida, Cha-
mffileonida, and Scincoide.

SAT/EIAN. A reptile belonging to
the order Sauria. The species of
fossil saurians are exceedingly nu-
merous, attaining in-many instances
a magnitude unknown among the
living orders of that class, and
which seems to have been peculiar
to those middle ages of geological
chronology that were intermediate
between the transition and tertiary
formations. It is in the oolitic
period, between the eras of the red
sandstones and the greensands, that
the gigantic saurians existed in
greatest abundance about the shores,
in the rivers, and on the land, in
these now cold regions of the globe.
Some of the saurians were exclu-
sively marine ; others amphibious ;
others were terrestial, ranging in
marshes and jungles, or basking on
the margins of estuaries, lakes, and
rivers. Even the air was tenanted
by flying lizards, under the dragon
form of pterodactyles.

SAtfEOBATRACHiA. The third order
of the class Amphibia, comprising
the proteus, siren, &c., and the
extinct genus Andrias.

SAUEOCE'PHALUS. A fossil saurian,
found in the oolite, and by Agassiz

S A U

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S C A

ranked among fishes. Its form
was adapted for swimming.

SAI/BOID. (from tmvpa, a lizard, and
ei8o?, form, Gr.) The name given
to a group of fishes found in great
abundance in the carboniferous and
secondary formations. The sauroid
fishes occupy a higher place in the
scale of organization, than the or-
dinary forms of bony fishes. In the
tertiary strata the sauroids almost
disappear, and are replaced by less
complex forms. The sauroid, or
lizard-like fishes, combine in their
structure, both in the bones and some
of the soft parts, characters which
are common to the class of reptiles.

SATJ'SSTJRITE. A combination of crys-
tallized serpentine with jade or
felspar. The jade de Saussure of
Brongniart. In its external cha-
racters it differs but little from
nephrite, but in its composition it
by no means resembles it. It was
first noticed by Saussure near the
lake of Geneva, scattered about in
rounded pieces and loose blocks.
Its colours are green, greenish
grey, or white with a slight tinge
of green or blue. Its specific
gravity is about 3*35. Before the
blow-pipe it fuses. It consists of
silex 49-0, alumine 24'0, lime 10'5,
soda 5*5, magnesia 3'75, oxide of
iron, 6*5. By many mineralogists,
Saussurite is included under ne-
phrite.

SAXICA'VA. A genus of bivalves, be-
longing to the family Lithophagi,
or stone-eaters.

SAXICA'VOTTS. Animals which make
holes in the rocks, either by boring
them, by means of some auger-like
process they possess; or by dissolv-
ing the rock, by some acid which
they secrete.

SAXIGENOTJS. Producing stone. This
term is more particularly applied
to those polypi which produce the
reefs and islands of coral, so abun-
dant in the Pacific Ocean and
Indian seas.

SCA'BROTTS. (from scabrosus, Lat.)

1. In entomology, applied to the
surface of an insect when covered
with small and slight elevations.

2. Applied to shells, when rough,
rugged, harsh, or like a file.

3. In botany, applied to stems that
are rough, from any little inequali-
ties or tubercles.

SCA'GLTA. (Ital.) A kind of chalk,
of a red colour. In an interesting
paper, by Prof. Sedgwick and Sir
E. Murchison, published in the
Philosophical Magazine for June
1829, on the relations of the secon-
dary and tertiary strata on the
southern flanks of the Tyrolese
Alps, the tertiary strata are
described as forming a vast series
of beds resting on scaglia or chalk.
The scaglia occurs in beds nearly
vertical; the upper ones contain
nodules and layers of flints ; their
colour is red, and their structure
fissile. The scaglia contains in some
parts ammonites and belemnites.

SCALA'BIA. A genus of marine tur-
reted univalves, with acute longi-
tudinal raised ribs. The aperture
nearly circular ; the margins unin-
terrupted, bordered, and reflected.

SCA'NDENT. (from scandens, climbing,
Lat.) A term applied to plants
which climb upon some support,
attaching themselves by fibres or
tendrils.

SCANSO'RES. The second order of the
class aves, or birds; the woodpecker,
cuckoo, and parrot are examples.

SCAPE. (from scapus, Lat.) In
botany, an herbaceous stalk, spring-
ing from the root, and bearing the
flower and fruit, but not the leaves.
The hyacinth is an example.

SCA'PHITE. (from scapha, a boat.)
So named from its supposed resem-
blance to a boat. The scaphite
resembles an ammonite partly un-
rolled, Scaphites are found in the
chalk, and in the greensand ; they
are believed to be altogether
extinct.

2 E

S C A

[394]

C H

SCAP'HOID. (from oicafai, a boat, and
et&>s, form, Gr.) The name given
to one of the carpal bones, from
its fancied resemblance to a boat,
or hollow oblong vessel.

SCA'POLITE. Pyramidal felspar. The
scapolith of Werner ; scapolithe of
Brochant ; paranthine of Haiiy. A
rare mineral, occurring massive,
and in long prismatic crystals. It
consists of silica 43 '83, alumina
35-43, lime 18-96. It is of a grey,
yellowish, greenish- white, or silver
white colour. Specific gravity from
3-68 to 3-71. Before the blow-
pipe it intumesces, and fuses into
a shining, white enamel. It is
found in beds of magnetic ironstone
and iron pyrites, at Arendal, in
Norway. Jameson divides this
species into three subspecies,
namely, radiated scapolite, foliated
scapolite, and compact scapolite.
Its name is derived from the pris-
matic form of its crystals.

SCA'PULA. The shoulder-blade.

SCA'PTTLAB. Pertaining to the shoul-
der-blade or scapula.

SCABF-SKIN. The cuticle or external
covering of the body ; called also
the epidermis.

SCA'BBBOITE. An earthy mineral oc-
curring near Scarborough, whence
its name, of a pure white colour,
consisting of alumina, silica, perox-
ide of iron, and water.

SCHAA'LSTEIN. Shell stone. The
schaal- stone of Jameson; pierre
calcaire testace*e of Brochant ; spath
en table of Haiiy. Called also
tabular spar or table spar. A
substance of a grey or pearly- white
colour, usually occurring in masses,
composed of thin laminee, collected
into large prismatic concretions.
It is very rare, and has been found
chiefly at Dognatska, in the Bannat.

SCELIDOTHE'BIUM. (from <r/ce\*s, hind
leg, and Orfplov, beast, Gr.) A
genus or subgenus distinct from
Megatherium and Megalonyx, but
of the same natural family; dis-

covered by Mr. Darwin in Patago-
nia, and so named by Prof. Owen.
The characters of this genus are
taken from the modifications of the
teeth and of the bones of the extre-
mities, especially of the astragalus.

SCHEE'LIUM. Another name for Tung-
sten.

SCHI'LLEE SPAB. (from scMlerm,
Germ.) The schiller spath of
Mohs. A genus of spars compri-
sing four varieties, namely, com-
mon schiller spar ; bronzite, or
hemiprismatic schiller spar; hy-
persthene, or prism atoidal schiller
spar; and anthophyllite, or pris-
matic schiller spar. The characters
of the genus are, the cleavage mo-
notomous, perfect. Metallic pearly
lustre. Hardness 3*5 to 6-0. Spe-
cific gravity 2-6 to 3*4.

SCHIST. (<rx*0ro9, Gr.) A term sy-
nonymous with slate. A rock, of
a fissile character, which may
easily be split.

SCHISTO'SE MI'CA. The name given
by Kirwan to mica slate,

SCHKEIDE'BIAN MEMBBANE. Thus na-
med from Schneider, who first de-
scribed it. The lining membrane
of the nostrils.

SCHOBL. (from Schorlan, a village
in Saxony.) Some mineralogists
comprise in one family, which they
term the Schorl family, topaz
schorlite, pyrophysalite, euclase,
emerald, iolite, schorl, epidote,
zoisite, and axinite. Others con-
sider tourmaline and schorl as one
mineral. Under the word schorl
we shall describe, not the family,
but the mineral known as the Schorl
of Werner, Le Schorl of Brochant,
the Tourmaline of Haiiy. Jameson
divides schorl into Precious Schorl
and Common Schorl. It is a
mineral, in general, easily recog-
nised. It most frequently occurs
in long prismatic crystals, more or
less regular, whose lateral faces

S C H

[ 395 ]

SCO

are almost always longitudinally
striated. These prisms usually
present six, nine, or twelve sides,
and are terminated at both ex-
tremities by three principal faces.
The principal form, not easily
obtained by mechanical division,
is an obtuse rhomb of which the
plane angle at the summit is
115° 34', or according to some an
obtuse rhomboid of 133Q 50' and
46° 10'. Phillips terms it a com-
bination of silica, alumina, oxide
of iron, and lime, with small pro-
portions of magnesia, potash, soda,
and boracic acid, and the analysis
of Gmelin give all these constitu-
ents. An attention to its electric
powers, its vitreous, conchoid al
fracture, and fusibility into an
enamel, will generally prevent it
from being confounded with other
minerals, more particularly from
hornblende, which it most resem-
bles.

SCHOBLA'CEOTJS. Eesembling schorl ;
containing schorl. The granite of
Dartmoor is very frequently por-
phyritic from the presence of large
crystals of felspar, and here and
there shorlaceous. The schorl not
unfrequently occurs in radiating
nests of variable size and abundance.

SCHOEL EOCK. A binary compound
of schorl and quartz, in which the
first considerably predominates.
The schorl rock of Cornwall, says
Jameson, is probably very inti-
mately connected with topaz rock ;
its geognostic relations and char-
acters are not well ascertained.

SCHO'ELITE. The Pycnite of Haiiy
and Brongniart; the Schorlous
beryll of Jameson. A mineral of
a straw colour, occurring at Alten-
burg, in Saxony, in a rock of
quartz and mica.

SCI'ENCE. (from scientia, knowledge,
Lat. science, Fr. sienza, It.) The
knowledge of many, orderly and
methodically arranged and digested,
so as to become attainable by one.

The knowledge of reasons and
conclusions constitutes abstract,
that of causes and their effects,
and of the laws of nature, natural
science.

SCITAMI'NE.E. One of Linnaeus's
natural orders of plants ; they are
all natives of warm climates : the
ginger, plantain, &e. are examples.
Scitamineous plants have been
found fossil in the strata of the
Isle of Sheppey.

SCLEE'OBTJS. (from oTcXiy/^os and o£ov?,
Gr. rough-tooth. A genus of fossil
fishes, discovered in the upper
Ludlow rock, and thus named by
M. Agassiz. It may be distin-
guished from Psammodus by the
raised pustules on the surface of
the teeth.

SCLEEO'TICA. | (from ovcX^os, hard,

SCLEBO'TIC. ) Gr.) The outermost
coat, tunic, or membrane of the
eye. It is exceedingly dense and
firm, and does not pass over more
than about four-fifths of the ball of
the eye, its place in front being
supplied by a transparent mem-
brane, the cornea, to permit the
passage of light.

SCO'LEZITE. A mineral haying one
equivalent of hydrated silicate of
lime, to one of silicate of alumina,
and two of water.

SCO'PIFOEM. (from scopa, a besom,
and forma, form, Lat.) Of the
form of a besom or broom. In
mineralogy, if a number of minute
crystals or fibres be closely aggre-
gated into a little bundle, with the
appearance of diverging slightly
from a common centre, they are
said to be scopiform.

ScoEBfcuLATE. In conchology, pit-
ted ; having the surface covered
with hollows.

SCO'EIA. (ffKwpt'a, Gr. scoria, Lat.)
The dross or scum of metals ; the
cinders of volcanic eruptions (then
used plurally, scoria) ; the recre-
mentitious matter of metals in a
state of fusion.

SCO

396 ]

SEC

SCOEIA'CEOTTS. Kesembling scoria ;
containing scoria.

SCO'EIOTIS. Drossy ; cindery ; excre-
mentitious.

SCORPION". (ffKopTrios, Gr.) A genus
of arachnidans, belonging to the
family Pedipalpi, order Pulmonarise.
The scorpion is remarkable, not
only for the powerful organs by
the aid of which it is able to seize
its prey, but also for its jointed
tail, terminating in a deadly sting.
The palpi are very large, with a
forceps at the extremity resembling
a hand ; the tail is composed of
six joints, the last joint terminating
in an arcuated and exceedingly
acute point or sting, which allow
the exit of a poisonous fluid, con-
tained in an internal reservoir.
The scorpion is provided, on each
side of the thorax, with four pul-
monary cavities, into each of which
air is admitted by a separate exter-
nal opening. The eyes are com-
pound, accompanied by stemmata.
A fossil scorpion has been dis-
covered by Count Sternberg in the
ancient coal formation at Chomle,
near Kadnitz.

SCEEW STONE. The name of a fossil
resembling, at first sight, a screw ;
if, however, the marks be care-
fully examined they will be found
to be circular, and not spiral.

SCEOBI'CULATED. (scroliculus, from
scrols, a furrow, Lat.) Furrowed ;
having small ridges and furrows.

SCETJ'BSTONE. A provincial term for
a species of calciferous sandstone.

SCY'PHIA. A genus of zoophytes.
Fossil scyphise occur in the oolitic
and cretaceous groups. In the
oolitic, forty one species have been
determined by Goldfuss and Mun-
ster ; in the cretaceous" group
twelve species have been deter-
mined by Goldfuss. Five species
are mentioned as having been found
in the grauwacke.

SEAM. A term used to designate a
thin stratum ; as a seam of coal.

SCTJ'TTJM. (scutum, Lat. a shield or
buckler.) A species of Echinite.
The name given by Klein to the
third section of the class Catocysti ;
the scutum of Klein is the Echin-
anthus of Leske.

SEA PEN. A purple-coloured zoophyte.
SE'CONDAEY FOEMA'TION. \ By se-
SE'CONDAEY STEATA. > condary

SE'CONDAEY EOCKS. ) rocks are

meant those stratified rocks older
than the tertiary, which contain
certain distinct organic remains,
and are now commonly called Meso-
zoic. The principal groups of the
secondary formations are as follows :
— 1. The cretaceous group, begin-
ning with the Maestricht beds, and
terminating in the lower greensand.
2. The Wealden group, commen-
cing with the Weald clay, and
closing with the Purbeck beds. 3.
The oolite, or Jura limestone group,
beginning with the Portland beds,
and ending with the inferior oolite.
4. The lias group. 5. The new
red sandstone group, commencing
with the Keuper and ending in the
red conglomerate. 6. The carbon-
iferous group, comprising the coal
measures, the mountain limestone,
and the old red sandstone. 7. The
graywacke group.

The secondary strata cover a
large portion of the habitable globe,
and are the immediate subsoil of
the most fertile districts of Europe.
The secondary strata are composed
of extensive beds of sand and sand-
stone, mixed occasionally with
pebbles, and alternating with de-
posits of clay, marl, and lime-
stone. The materials of most of
these strata appear to have been
derived from the detritus of primary
and transition rocks; and the
larger fragments, which are pre-
served in the form of pebbles,
often indicate the sources from
which these rounded fragments
were supplied. Six substances are
interstratified in this system : aron-

SEC

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SEC

aceous, argillaceous, and calcareous
rocks form the principal masses,
and are associated with beds of
chert, iron-stone, and coal.

It is in the strata belonging to
the secondary formations that the
bones of enormous reptiles are first
discovered. The peculiar feature
in the population of the whole series
of secondary strata, was the pre-
valence of numerous and gigantic
forms of Saurian reptiles.

"From the examination," says
Mantell, "of the organic remains
of the secondary formations, we
arrive at the following results :
that the seas, lakes, and rivers,
during the geological epoch termed
secondary, were peopled by fishes,
mollusca, Crustacea, radiaria, poly-
paria, and other zoophites; all of
extinct species, and presenting as
a whole, a greater discrepancy with
existing forms, than those of the
tertiary."

The commencement of the secon-
dary epoch is a marked one, depend-
ing on a great change having taken
place in the character of animal
and vegetable life, in the interval
between the formation of the last
of the primary, or paleozoic rocks,
and the first of the secondary.
The discovery, however, of the St.
Cassian beds, in the Austrian Alps,
has tended to lessen that great
interval, and to diminish the extent
of the change ; those beds having
been found to contain fossils of an
intermediate character.

With the cretaceous system ends
the long series of deposits which
are, by general consent, ranked
as strata of the secondary periods
of geology. Prof. Phillips says,
" turning to the organic remains of
the several secondary systems, it is
apparent that, within the period of
time which elapsed between the
deposition of the primary and ter-
tiary strata, two very distinct as-
semblages of terrestrial plants had

flourished, and become extinct. The
ancient and abundant flora of the
carboniferous era, with its lepido-
dendrae, sigillaria3, and calamites,
had been replaced by new races of
zamiaa and cycadse, which, in their
turn, vanished from the northern
zones of the globe before the cre-
taceous system. The marine zoo-
phyta were changed. One total
change had come over the Crustacea,
—not a single trilobite being known
in the strata more recent than coal :
the brachopodus conchifera, the
gasteropodous and cephalopous
mollusca were equally altered.
Two large assemblages of fishes
had vanished before the deposition
of the chalk ; and both on the land,
and in the sea, gigantic reptile
forms had come into being, re-
produced themselves to a marvel-
lous extent, and then all perished
with the close of the secondary
period."

" How, then, can they, by whom
the magnificent truths of elapsed
time and successive creations have
been put in clear and strong evi-
dence,— how can they be expected
to yield to false notions of philo-
sophy, and narrow views of religion,
the secure conviction that, in the
formation of the crust of the earth,
Almighty "Wisdom was glorified,
the permitted laws of nature were
in beneficent operation, and thou-
sands of beautiful and active things
enjoyed their appointed life, long
before man was formed of the dust
of the ancient earth, and endowed
with a divine power of compre-
hending the wonders of its con-
struction ? It is something worse
than philosophical prejudice, to
close the eyes of reason on the
evidence which the earth offers to
the eyes of sense ; it is a dangerous
theological error to put in unequal
conflict a few ill- understood words
of the Pentateuch, and the thousands
of facts which the finger of God

SEC

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SEP

has plainly written in the book of
nature ; folly, past all excuse, to
suppose that the moral evidence of
an eternity of the future shall be
weakened by admitting the physical
evidence for an immensity of the
past."

SE'CTILE. (from sectilis, that may
be easily cut, Lat.) A term in
mineralogy, applied to minerals,
when, being cut with a knife, the
separated particles do not fly away,
but remain on the mass. Sectile
minerals are those which are mid-
way between malleable and brittle.
"A slice or portion cut from a
sectile mineral is fragile, and the
new surface on the mass is smooth
and shining." — Phillips.

SECT/RIFORM. (from securis, a hatchet,
Lat. and form.) Hatchet-shaped :
a term applied to shells and to
leaves.

SEDIMENTARY ROCKS. Rocks which
have been deposited by water.

SEED VE'SSEL. In botany, the pericarp.

SE'LENITE. ftffcXifvrnf*, Gr. selemte,
Pr.) Sulphate of lime, or crystal-
lized gypsum. A transparent and
highly crystallized variety of gyp-
sum. The crystals of selenite are
frequently united, or collected into
groups of various forms. Selenite
consists of lime 33-0, sulphuric
acid 44'8, water 21-0. It is found
abundantly in the gypsum and salt
formations. The primitive form of
its crystal is a dodecahedron, which
may be conceived as two four- sided
pyramids, applied base to base, and
which, instead of terminating in
pointed summits, are truncated
near the bases ; so that the sides of
the pyramids are trapeziums, each
terminating in a rhomb. It causes
double refraction. Before the blow-
pipe it melts into a white enamel.

SELE'NIUM. (from ffeXyvrj, the moon,
Gr.) One of the simple or ele-
mentary bodies, and a non-con-
ductor of electricity. According to
Prout, it appears to constitute the

connecting link between sulphur
and the metals. When in mass,
selenium has the aspect of lead and
a metallic lustre, but pulverized it
displays a deep red colour. Speci-
fic gravity 4-3. Its equivalent is
39-6 : symbol Se.

SE'MI-O'PAL. A variety of opal. The
Halbopal of Werner; La demi-
opale of Brochant ; Quartz resinite
commune of Haiiy. The colours
of semi-opal are white, grey, green,
red, brown, and blue. Fracture
imperfectly conchoidal. Specific
gravity 2 to 2'5. It is infusible
before the blow-pipe. It consists
of silica 85, alumina 3, oxide of
iron 1'74, carbon 5, ammoniacal
water 8, with a fracture of bitu-
minous oil : or, according to
another analysis, of silica 82*7,
water 10, oxide of iron 3, alumina
3-5.

SENSO'RIUM. (sensorium, Lat. sen-
sorium, Pr.) That part of the
brain where the senses transmit
the impressions or perceptions to
the mind.

SE'PAL. This word was invented by
botanists to distinguish the several
parts of the calyx from those of
the corolla.

SE'PIA.

1. The name given by Linnaeus to
the cuttle-fish. See Cuttle-fish.

2. The ink of the cuttle-fish. This
has been found in a beautiful state
of preservation in fossil ink-bags of
sepiaB in the lias at Lyme Regis.
The common sepia used in drawing
is from the ink-bag of an oriental
species.

SEPIOSTA'IRE. The name given by
Blainville to the internal bone of
the sepia or cuttle-fish. The ab-
sence of a siphuncle renders the
sepiostaire an organ of more simple
structure, and of lower office, than
the more compound shell of the
belemnite.

SEPTA'RIA. (from septa, partitions,
Lat.) Spheroidal concretions, va-

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SEE

rying from a few inches to a foot in
diameter, and divided into cells or
chambers of irregular form ; some-
times they are nodules of clay,
having the chambers filled with
spar; they are usually found, in
argillaceous strata. Masses of ar-
gillaceous limestone, traversed in-
teriorly by cracks passing in
different directions, and containing
calcareous spar. Septaria were at
one time considered to be confined to
the London clay deposit, and to be
characteristic of it, but subsequent
discoveries have proved the in-
correctness of that opinion.

SE'PTHM:. (septum, Lat.) A partition.
The plates dividing the chambers
of multilocular shells are termed
septa; a partition separating cer-
tain portions of the brain is called
the septum ; and the cartilaginous
partition of the nostrils is called
the septum of the nose.

SE'EAPHIM. The name given by the
workmen to impressions of a sort
of fossil lobster or gigantic crus-
tacean in the old red sandstone.

SE'BOLIS. A genus of crustaceans,
affording the nearest approach
among living animals to the ex-
ternal form of the trilobite. The
greatest difference between the
serolis and trilobite consists in the
former possessing a fully developed
series of crustaceous legs and
antennae, whilst the trilobite does
not display any traces of either of
these organs.

SE'BPENTINE. A mineral substance
deriving its name from its spots
and variegated colours, supposed
to resemble the skin of the serpent ;
its colours and their peculiar ar-
rangement are in great measure
characteristic. It sometimes forms
whole rocks. It differs from horn-
blende in containing a larger por-
tion of magnesia and a smaller
quantity of iron. There is, how-
ever, an intimate connection be-
tween serpentine and hornblende,

as the latter is observed, in some
situations, to be changed into ser-
pentine by contact with limestone.
Specific gravity from 2-5 to 2*7.
Before the blow-pipe it hardens
but does not fuse. Its constituents
are magnesia 34*5, silex 28'0,
alumine 23-0, lime 3-5, water 10-5,
oxide of iron 4-5 = 101. There
are two varieties, the precious and
the common serpentine. When
serpentine is found intermixed
with patches of crystalline white
marble, it constitutes a stone deno-
minated verde antique. Some crys-
tallised varieties have obtained the
name of diallage, or Schiller spar.

SE'BPTTLA. A genus of the order
Tubicola, class Annulata. The
animal a terebella ; shell univalve,
tubular, generally adhering to
other substance; often separated
internally by septa at uncertain
distances. Serpulas are generally
littoral, attached to rocks, stones,
shells, crustaceans, corals, and
other marine bodies; sometimes
several species are found on one
stone or shell. Scapulae may com-
monly be seen upon the shells of
lobsters, crabs, oysters, &c., to
which they adhere by the lower
surface, looking like small worms
creeping upon them. Wherever
the sea is or has been, they abound
either in a recent or fossil state.

SEBPULI'NA. An order of the anne-
lida of MacLeay, who thus describes
them " sedentary animals without
eyes or antennae. They live in
tubes which are either a natural
transudation of their body, and are
membranaceous or calcareous, or
the tubes are semifactitious, compo-
sed of agglutinations of sand, &c."

SEBPULI'TES LONGI'SSIMUS. The name
assigned by Sir K. Murchison to a
fossil shell of the Upper Ludlow
Rock. The following description
is taken from his Silurian System.
" Very long, hardly diminishing
in diameter, compressed, smooth,

SEE

[ 400 ]

H A

slightly tortuous, composed of nu-
merous thin layers of shell contain-
ing much animal matter. In
structure, this fossil resembles the
Serpula compressa, but it does not
diminish so rapidly. "Width half
an inch. It is found near Ludlow
very abundantly, and generally
throughout the Upper Ludlow B-ock
of Salop, Hereford, Radnor, &e."

SE'EEATE. | (serratus, Lat.) Jagged ;

SE'EEATED. ) notched.

1. In botany, applied to leaves,
the margins of which resemble a
saw, the teeth pointing towards
the extremity of the leaf.

2. In entomology, applied to the
bodies of insects, the margins
having jagged incisions, like the
teeth of a saw.

SE'EETJLATE. } (from serrula, a little

SE'EEULATED. ) saw, Lat.) When
the edges of leaves or margins of
shells are very finely jagged or
notched, they are said to be ser-
rulated, and not serrated.

SEETULA'EIA. A genus of aborescent
corals belonging to the family Tu-
bularii.

SE'ETJM. (serum, Lat. serum, Fr.)
The thin, watery, transparent part
of the blood.

SE'SAHOID. (from <rc<rap/, an Indian
grain, and et£ov, resemblance, Gr.
sesamoide, Fr.) The name of some
exceedingly small bones found at
the root of the thumb or great-toe.
It is the opinion of some naturalists
that sesamoid bones are rather to
be regarded as depositions of bony
matter, in parts disposed to its
reception, as ligament, cartilage,
&c., than as intrinsic portions of
the skeleton ; they are larger and
more numerous in the hands and
feet of such as take laborious
exercise.

SE'SQTJI. (A contraction of semisque,
Lat. signifying and a half.) A
prefix to many words signifying
the quantity and a half more. A
sesqui-oxide is therefore a combi-

nation with one equivalent and a
half of oxygen.
SE'SSILE. (from sessilis, seated, Lat.)

1. In botany, applied to flowers
when placed directly on the branch
or stem ; also to leaves when they
grow directly from the stem,
branch or root, without any foot-
stalk : any part of a plant which
commonly is borne on a stalk, is
said to be sessile when it has no
stalk.

2. Applied to animals. No truly
sessile animal is provided with sight.

SE'VEEITE. An earthy mineral con-
sisting of alumina, silica, and
water. It is found in small mas-
ses, white, without lustre, and
slightly translucent. It was dis-
covered near St. Sever, in Prance,
whence its name.

SETA'CEOUS. (from seta, a bristle,
Lat.) Bristle-shaped; bristly.

SHALE, (schale. Germ. Schiefer Thon
of Werner : argile schisteuse of
Brochant.) Shale occurs masive
only; its usual colour is grey,
sometimes blueish, blackish or yel-
lowish. Often easily cut by the
knife. Specific gravity about 2-64.
Adheres to the tongue, yields an
argillaceous odour when breathed
upon, absorbs water considerably,
and often falls gradually to pieces
in that liquid, but never forms a
paste. Slatezclay ; indurated slaty
clay.

Fracture slaty, sometimes nearly
earthy, and is dull unless it con-
tains casually imbedded mica,
which renders it glimmering. It
is fusible before the blow-pipe. It
is found resting upon, as well as
interposed between, beds of coal,
which it invariably accompanies.
Some shales are highly bituminous
and burn with a bright flame.
Shales frequently contain impres-
sions of fishes, reeds, and ferns.

SHA'NKLIN-SAND. (The Glauconie
Sableuse of the French geologists.)
Called also the lower green sand.

S H A

[ 401

A marine deposit of silicious sands
and sandstone of various shades of
green, red, brown, yellow, ferugi-
nous, grey, and white, with subor-
dinate beds of cherts and silicious
limestones, constitute the formation
called the Shanklin sand, or the
lower green sand. It is the lowest
member of the . cretaceous group,
intervening between the gault
above and the weald clay below.
The beds consists of an aggregation
of sand, with comminuted shells
and fragments of corals, impreg-
nated with iron, and containing the
remains of myriads of shells, poly-
paria, &c. Dr. Fitton divided the
Shanklin sand into three distinct
parts : the first or uppermost con-
sisting of sand, with irregular con-
cretions of limestone and chert,
sometimes disposed in courses
oblique to the general direction of
the strata.

The second consists chiefly of
sand, but in some places is so mixed
with clay, or with oxide of iron, as
to retain water: it is remarkable
for the great variation in its colour
and consistency.

The third and lowest group
abounds much more in stone ; the
concretional beds being closer
together and more nearly continu-
ous. The Shanklin, or lower green,
sand, is separated from the upper
by the gait or Folkstone marl.
SHARK, (from icap^apla^, Gr.) The
squalus of Linnaeus. A genus of
fishes belonging to the family
Selachii, order CJiondropterygii
Branchiis Fixis. The shark is a phos-
phoric fish. That tribe of sharks,
called by the French Eeguins,
which is thought to be synonymous
with the carcharias of the Greeks,
and one of which was probably the
monster that swallowed Jonah, are
stated to exceed thirty feet in
length. The genus of sharks may
be considered as one of the most
universally diffused, and most vora-

] S H A

cious, of modern fishes. Several
rows of teeth are lodged in each
jaw, but one only of these rows
projects, and is in use at the same
time ; the rest lying flat, but ready
to rise in order to replace thoee
that have been broken off, or worn
down. The shark is oviparous or
ovo-viviparous, according to cir-
cumstances. The vertebral column
is prolonged into the upper lobe of
the tail, and the tail is of great
service in enabling the shark to
turn its body so as to bring the
mouth, which is placed downwards
beneath the head, into contact with
its prey. Sharks appear to have
existed throughout every period of
geological history. M. Agassiz
has separated the sharks into three
sub-families, each containing forms
peculiar to certain geological epochs,
and which change simultaneously
with the other great changes in
fossil remains. The first of these
sub-families, or the Cestracionts,
commence with the transition
strata, appearing in every subse-
quent formation till the commence-
ment of the tertiary. Of the Ces-
tracionts, one representative only
now remains, namely, the Cestra-
cion Philippi, or Port Jackson
shark. The Cestracionts possessed
large polygonal, obtuse, enamelled
teeth, covering the interior of the
mouth with a kind of tesselated
pavement. The second sub-family,
or Hybodonts, commenced with
the muschel-kalk, is found through-
out the whole of the oolitic deposits,
and disappears at the commence-
ment of the cretaceous group. The
teeth of the Hybodonts were inter-
mediate between the blunt polygo-
nal teeth of the Cestracionts and
the sharp-edged cutting teeth of
the Squaloids. The third sub-
family, termed Squaloids, appeared
at the commencement of the chalk
deposits, and continues downwards
to the present period. In the
2 F

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[ 402 ] 8 H 0

Squaloids, the teeth are smooth on
the outer side, and plicated on the in-
ner ; sometimes the edge is serrated.
SHELL, (schah, Germ.) The hard
covering of anything ; the covering
of a testaceous or crustaceous ani-
mal. The crustaceous coverings ef
animals, as of echini, crabs, lobsters,
cray-fish, &c., are composed of the
same ingredients as bones ; but the
proportion of carbonate of lime far
exceeds that of phosphate of lime
in shells.

The process employed by nature
for the formation and enlargement
of the shells of the mollusca was
very imperfectly understood prior
to the investigations of Reaumur.
His experimental enquiries have
established these two general facts ;
first, that the growth of a shell is
simply the result of successive
additions made to its surface, and,
secondly, that the materials consti-
tuting each successive layer are
supplied by the organized fleshy
substance called the mantle, and
not by any vessels belonging to the
shell itself. The connexion be-
tween the animal and the shell
may be regarded as mechanical
rather than vital; for whatever
portion of vitality it might have
possessed when first deposited, all
trace of that property soon dis-
appears.

Shells are found fossil in the most
ancient strata of the transition
period that contain any traces of
organic life, and many of these
agree so closely with the existing
species, that we infer their func-
tions to have been the same, and
that they were inhabited by ani-
mals of form and habits similar to
those which fabricate the living
shells most nearly resembling them.
The most prolific source of organic
remains has been the accumulation
of the shelly coverings of animals
which occupied the bottom of the
sea during a long period of conse-

cutive generations. A large pro-
portion of the entire substance of
many strata is composed of myriads
of these shells, reduced to a commi-
nuted state by the long-continued
movements of water. Minute ex-
amination discloses occasionally
prodigious accumulations of micro-
scopic shells, no less surprising by
their abundance, than their extreme
minuteness; the mode in which
they are sometimes crowded to-
gether, may be estimated from the
fact, that Soldani collected from
less than an ounce and a half of
stone, found in the hills of Tus-
cany, ten thousand four hundred
and fifty-four microscopic cham-
bered shells. Of several species of
these shells, four or five hundred
weigh but a single grain ; of one
species, a thousand individuals
would scarcely weigh one grain;
and great numbers of them will
pass through a paper in which
holes have been pricked with a
needle of the smallest size.

SHELL MAEL. A deposit of calcareous
earth and clay containing shells.

SHI'NGLE. fscJiindel, Germ.) The
loose, water-worn, pebbles on the
sea- shore.

SHOKLA'CEOUS. A name given by Dr.
Boase to certain primary rocks
which contain shorl; containing
shorl.

SHORL BOCK. A genus of primary
rocks. Dr. Boase says, " Shorl-
rock is composed of quartz and
shorl, with the occasional addition
of a third mineral. Its species
generally possess the structure of
granite: but sometimes the con-
stituents are so intimately blended
that they cannot be distinguished,
forming homogeneous m asses which,
however, are so well characterized,
that they cannot easily be mistaken
for any other rock. Shorl-rock
occurs in distinct beds, but more
commonly in immense veins; in
both forms it is found in granite

SIB

[405 ]

S I L

and protogine, and also among the
schistose rocks. The following
species are enumerated : granular ;
large grained; fine grained; gra-
nitic; quartzose; compact; zoned;
agate-like ; porphyritic. They all
occur in Cornwall.

SI'BERITE. Another name for Rubel-
lite, or red tourmaline.

SI'DERO-CA'LCITE. The name given by
Kir wan to brown spar ; the braun
spath of Werner.

SI'ENITE. ) (from Syene, a city of

SY'ENITE. ) Egypt, where this rock
occurs in abundance, and whence
the Eomans obtained it for archi-
tectural and other purposes. ) Wer-
ner gave the name of sienite to
aggregates composed of felspar,
hornblende, and quartz ; or of fel-
spar, hornblende, quartz, and mica.
Sienite is the roche feldspathique
of Haiiy. It often bears the ge-
neral aspect of a granite. Felspar
and hornblende may be deemed its
two constant and essential ingre-
dients, but it frequently contains
quartz and mica, and occasionally
talc and epidote. It is the presence
of hornblende, as a constituent
part, which distinguishes this rock
from certain granites, that acci-
dentally contain hornblende. The
structure of sienite is sometimes
slaty, commonly granular. Green-
stone and sienite are essentially
composed of the same ingredients,
namely, felspar and hornblende ;
from granitic greenstone there is a
transition to sienite, and from sie-
nite to true granite. The colour
of sienite is usually grey, but this
is affected by the ingredients en-
tering into its composition. Prof.
Delesse says, "the rose-coloured
syenite of Egypt is formed of
quartz, orthose, oligoclase, mica,
and frequently also of hornblende."

SIEXI'TIC. Containing sienite; re-
sembling sienite; possessing some
of the characters of sienite. Sie-
nitic granite contains hornblende.

Sienitic porphyry is fine-grained
sienite containing large crystals of
felspar.

SIGAEE'TTJS. A genus of marine uni-
valve shells belonging to the family
Macrostomata. It is a depressed,
oval, nearly auriform shell, with a
short spiral columella : the aper-
ture entire, wide, spread out to-
wards the summit of the right lip,
and longer than wide. It is a
Tuscan fossil, and exceedingly rare.
The living sigaretus is found in
sand at depths varying from five to
fifteen fathoms.

SIGILLA'BIA (from aigillum, Lai)
The name given by Brongniart, to
certain large, and, in modern vege-
tation, unknown forms of plants
discovered in the coal formation:
the name has been assigned from
the peculiar impressions on the
stems. The stems are of various
sizes from a few inch s to upwards
of three feet in circumference, and
of great length. A stem found in
Craigleith Quarry, near Edinburgh,
was forty-seven feet in length, the
bark being converted into coal.
Stems nearly as long, .and four feet
and a half in diameter, have some-
times been found in the coal series
in the north of England. They are
scattered throughout the sandstones
and shales that accompany the coal,
and may occasionally be seen in the
coal itself. These stems are in-
clined in all directions, and some
of them are nearly vertical : they
are supposed to have been hollow,
like the reed, and with but little
substance. Brongniart has enume-
rated nearly fifty species.
SI'LEX. (silex, Lat. flint.) An oxide
of silicon, constituting the greater
part of all the rocks of which the crust
of the earth is composed. Pure silex
is perfectly white, it has neither
taste nor smell, and its spec. gr. is
2'26. Silex consists of oxygen
in the proportion of 50 per cent,
united with the base silicium ; it

I L

404 ]

S I L

is found in the greatest purity in
quartz or rock crystal.
SI'LICA. A peroxide of Silicon. One
hundred parts of silica contain
48-4 of silicium, and 51'6 of oxy-
gen. It is white ; specific gravity
2-6 ; it is fusible.

SI'LTCATE. A union of silica with
some other substance as a base,
and by uniting in a double or treble
proportion, becomes a bisilicate or
trisilicate. The principal silicates
are those of alumina, potash, soda,
magnesia and lime.
SILICIC A'LCE. The quartz agathe cal-
cifere of Haiiy : silex silicicalce of
Brongniart. A substance occur-
ring in amorphous masses, in thin
beds, under strata of compact lime-
stone in Provence. It is of a grey
or brown colour, sometimes nearly
black. It effervesces with nitric
acid, and before the blow-pipe
fuses into a white scoria. It is a
mixture of flint and carbonate of
lime.

SILICIOUS SINTER. The Kiesel-sinter
of Werner and Klaproth. Quartz
agathe concretionnee thermogene of
Haiiy. Quartz hyaline concretionee
of jBrongniart. An earthy mineral,
arranged by some mineralogists as
a subspecies of quartz. Its usual
colours are white, greyish-white,
reddish- white, yellowish- grey, and
yellow. According to the analysis
of Klaproth it consists of silica 98,
alumina 1'5, iron 0'5. Specific
gravity 1 '8 1 . It is infusible before
the blow-pipe. It is found in the
neighbourhood of thermal springs
containing silex in solution, and is
deposited from them ; more espe-
cially by the hot springs of Iceland.
SILIC'IFEROUS. (from z%lext flint, and
fero, to bear, yield, or contain,
Lat.) Yielding or containing
silex ; as the pink siliciferous oxide
of manganese.
SILI CIFY. To convert into flint ; to

petrify.
SILICIFI'CATION. Called also petri-

faction. The conversion of any
substance into stone by the infil-
tration of silicious matter.
SILI'CIUM. | Silicon was discovered by
SI'IJCON. j Berzelius in 1824. It
is of a dark nut-brown colour,
without any metallic lustre ; in-
combustible in air or in oxygen
gas ; but oxidizable by certain
methods, by which it is converted
into silica or silicic acid. Its
equivalent is 7*5 ; its symbol Si.

" Silicon is now shown not to
be a metal, but to be nearly allied
to carbon in some of its properties.
It will combine with the metals
like carbon, especially with alumi-
num, forming cast aluminum, as
carbon and iron form cast iron." —
Jukes. The hitherto undecomposed
base of silica or silex. Of the
metallic bases of the alkalies and
earths, silicium is the most abun-
dant on the surface of our planet,
silica entering so largely into the
composition of both chemical and
mechanical rocks.

SILI'CTJLOTJS. Having small pods or
husks.

SI'LIQUA. (Lat.) A pod ; a long
seed vessel of two valves, separated
by a linear receptacle, on whose
edges the seeds are ranged alter-
nately.

SILIQUA'RIA. A genus of marine uni-
valves, found both fossil and recent.
It is a tubular shell, spiral at its
beginning, continued in an irregular
form ; divided laterally, through
its whole length, by a narrow slit,
and formed into chambers by entire
septa. Recent siliquariaB have been
found in sponges ; they may be
distinguished from serpula3 by the
longitudinal slit. Cuvier places
the genus in the order Tubulibran-
chiata.

SI'LIQTJOSE. } Bearing pods. A term

SI'LIQUOUS. j applied to plants hav-
ing that sort of pericarp denomi-
nated a pod or legume.

SILL. A provincial term signifying

S I L

[ 405 ]

I L

a bed or stratum ; as the whinstone
sill. The great bed of basalt in
Northumberland is called the
Whinstone Sill.

SI'LLIMANITE. A dark grey or brown
mineral, composed of silica 42'6,
alumina 54'1, oxide of iron 1*9,
water 0-5, discovered at Say brook,
in Connecticut, and named after
Prof. Sillirnan.

SILT. The deposit of running water ;
mud.

SILT. To silt up, to fill with mud,
sand, or other matter deposited by
running water. The verb is com-
monly used with the word up im-
mediately following, as the silting
up of rivers ; estuaries known to
have been silted up, &c.

SI'LVAN. The name given by Werner
to the metal tellurium.

SI'LVEE. (silber, Germ.) One of the
simple or elementary bodies, and
included in the subdivision termed
metals. When pure, it is nearly
white. It is superior to gold in
lustre, and inferior to it in malle-
ability ; it is however so malleable
that it may be beaten out into
leaves not exceeding 100,000th of
an inch in thickness. It is very
ductile, surpassing gold in tenacity,
but inferior to iron, copper, and
platinum. It may be drawn out
into wire of greater fineness than
human hair. It is harder than
gold, but softer than copper, and
may be easily cut by a knife. Its
specific gravity is 10'47. Silver
fuses at a temperature of about
1,000 degrees Fahr. It is not
oxidated by exposure to the atmos-
phere, but becomes tarnished by
sulphureous vapours. It is taste-
less, and free from smell. It is
soluble in nitric acid. Silver for
domestic purposes, as well as that
made into coin, is rendered harder
by an alloy of copper. The stand-
ard silver of this country consists
of eleven ounces two pennyweights
of pure silver and eighteen penny-

weights of copper. Silver has been
known from the earliest ages. It
is found native and in ores of
several kinds. The ores of silver
occur in metallic veins, traversing
primary rocks. There are many
ores which yield silver that are not,
strictly speaking, ores of silver.
Although the mines of Europe yield
considerable quantities of silver,
yet it is to Mexico and Peru that
we are indebted for the main sup-
plies. The mines of Potosi have
paid a royal duty on silver valued
at £234,700,000 sterling.
SILU'EIAN. The name given by Sir
R. Murchison to an upper subdi-
vision of the sedimentary strata
found below the old red sandstone.
He assigned this name to these
strata from their being best de-
veloped in that portion of England
and Wales formerly included in the
ancient British kingdom of the
Silures. The Silurian rocks are
divided into upper and lower : the
upper Silurian rocks comprise the
Ludlow formation and the Wenlock
formation ; the Ludlow formation
consisting of the upper Ludlow
rock, the Aymestry limestone, and
the lower Ludlow rock ; the Wen-
lock formation consisting of the
Wenlock limestone and the Wen-
lock shale : the lower Silurian
rocks are subdivided into the
Caradoc formation and the Llan-
deilo formation ; the Caradoc for-
mation consisting of flags, sand-
stones, grits, and limestones ; the
Llandeilo formation, of calcareous,
dark-coloured flags, with sandstone
and schist. The whole of the
Silurian rocks attain a thickness
in some parts of seven thousand
five hundred feet. They are all
marine deposites. The Silurian
rocks, though ancient, are not the
most ancient of the fossiliferous
strata. They are but the upper
portion of a succession of early
deposits, which it may hereafter be

SIM

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SIP

found necessary to describe under
one comprehensive name. For
this purpose Sir R. Murchison pro-
poses the term Protozoic, thereby
to imply the first or lowest forma-
tion in which animals or vegetables
occur. "Acting upon the principle
which guided "William Smith in
subdividing the oolitic system of
our island, I have named the rocks
of the Silurian system from places
in England and Wales, where their
succession and age are best proved
by order of superposition and im-
bedded organic remains, and have
termed them, in descending order,
the Ludlow, Wenlock, Caradoc,
and Llandeilo formations. Each
subdivision is characterized by a
corresponding suite of organic
remains, while the whole was for-
merly considered to be one assem-
blage, without definite sequence,
and was included under the names
greywacke or transition limestone"
The Silurian rocks consist of a
complete succession of fossiliferous
strata, interpolated between the old
red sandstone and the oldest slaty
rocks. In the lower or Cambro-
Silurian rocks we know of no
plants, with the exception of a few
sea-weeds : the animal remains are
those of zoophyta, polyzoa, brachi-
opoda, conchifera, gasteropoda,
cephalopoda, echinodermata, anne-
lida, and Crustacea (chiefly trilo-
bites). JS"o unquestionable remains
of any higher order of animals have
as yet been discovered. In the
upper Silurian rocks, many generic
forms make their appearance, not
met with in the lower series, and
many appear to have existed during
that period only. Two genera offish
have also been discovered, Onchus
and Plectrodus ; of the latter, three
species have been distinguished ;
the Plectrodus disappears with this
period. — Jukes.

SI'HPLE. (simplex, Lat. simple, Er.
semplice, It.)

1. In botany, applied to roots,
when undivided; to a leaf, when
consisting of only one leaf, and not
divided into leaflets, &c., &c.

2. In mineralogy, a term applied
to elementary, or undecomposed
substances : these are about 60 in
number, and are described under
the article " elementary substances."
The mineralogist and the geologist
consider those minerals as simple
and homogeneous, which present
no difference of qualities to our
senses throughout the mass, al-
though the chemist may discover
that such minerals are composed of
two or more elementary substances.

SINI'STBAL. A term applied to shells,
where, in consequence of the heart
being placed on the right side, the
turns of the spiral are made to the
left. These shells are termed sm-
istral, or reversed.

SI'NTEE. (sinter, Germ.) Calcareous
sinter is a variety of carbonate of
lime, and may be either stalactical,
tuberose, reniform, globular, cylin-
drical, tubular, branched, or in
large undulated masses. It is
composed, whatever may be its
form, of a series of successive layers,
concentric, plane, or undulated,
and nearly or quite parallel.

Silicious sinter is an opaline
silica, deposited on the margins of
some hot springs. Some mineralo-
gists have established three sub-
species, namely, common silicious
sinter, opaline silicious sinter, and
pearly silicious sinter.

SI'NTJATE. j (sinnatus, Lat.) In bot-

SI'NUATED. j any applied to leaves
when the margins are cut into wide
rounded openings, as in the leaf of
the oak.

SI'NUS. (sinus, Lat. a bag, sinus, Er.)

1. In anatomy, a cavity or cell; a
narrow passage.

2. In conchology, a groove or
cavity.

SI'PHON. | (siphon sm&siphunculus,
SI'PHTJKCLE. j Lat.) An hydraulic

SIP

[407]

fi L 0

apparatus belonging to chambered
or polythalamous shells, passing
through the several chambers, and
terminating in a large sac, which
surrounds the heart of the animal.
The use of the siphunculus appears
to be the enabling the animal to
rise to the surface, or descend to
the bottom of the water, by in-
creasing its specific gravity.

SIPHO'NIA. A genus of zoophytes,
species of which have been discov-
ered in the chalk and in the green-
sand. One species also has been
found in the oolite. "A fossil
animal, with a polymorphous body,
supported by a stem proceeding
from a fusiform or ramose root-
like pedicle ; the original substance
spongeous, and pierced by a bundle
of tubes derived from the pedicle,
passing through the stem, then
ramifying and terminating on the
surface of the body." — Parkinson.

SI'PHTJNCLED. Possessing a siphuncle ;
formed with a siphuncle.

SI'TU. (situs, Lat.) " In situ " is a
term used in mineralogy, when a
mineral is in its natural position or
place ; in its native site.

SKI'DDAW SLATE, (from Mount Skid-
daw.) The Skiddaw slates form
the lower division of the Cambrian
group. They are of a thickness of
6,000 feet.

SKO'LEZITE. An earthy mineral, nearly
allied to Thomsonite. It occurs at
Pargas, in Finland.

SKO'EODITE. (from GicopoSov, garlick,
Gr.) A mineral of a leek-green or
brown colour ; an arseniate of iron.
Before the blow-pipe it fuses, giving
out a smell of garlick, from which
circumstance it has obtained its
name.

SKO'KZA. The epidote skorza of Brong-
niart ; epidote arenace of Haiiy. A
variety of epidote. See Epidote.

SLAG, (schlacke, Germ, slagg, Dan.)
The drop or recrement of metal.

SLATE. A kind of clay, of a structure
termed schistose, which admits of

being split into thin layers of con-
siderable extent. Slate is commonly
of a bluish or greenish colour, with
a silky lustre. It consists of silex
50'0, alumina 25*0, oxide of iron
11-3, manganese 1-6, potash 4-8,
carbon 0*3, water 7*5. It is opake ;
may be scratched by the knife ; and
fuses into a blackish slag.

SLATE CLAY. See Shale.

SLA'TY. Kesembling slate ; containing
slate; composed of parallel thin
plates which admit of being sepa-
rated by splitting.

SLATE SYSTEM. This group is sub-
divided into, 1st, the Plynlymmon
rocks, consisting of grauwacke and
grauwacke slate, with beds of con-
glomerates, the thickness of the
whole being estimated at several
thousand yards. 2nd, The Bala
limestone, a dark limestone asso-
ciated with slate, containing shells
and corals. 3rd, The Snowdon
rocks, consisting of fine-grained
slates, of various shades of colour,
and of fine and coarse grauwacka
and conglomerate. In the strata
of the slate system are found the
most ancient organic remains.

SLI'CKENSIDES.

1. A provincial name for a variety
of galena.

2. "It sometimes happens," says
Mr. Phillips, " that the vein- stuff
of each wall of a vein is nearly
compact, both so completely occu-
pying the vein, that they meet
together in close contact in the
middle. The two faces in contact
appear as though they had been,
polished, and are ribbed, or rather
fluted, horizontally ; and the face of
each is sometimes covered by a
remarkably thin coating of lead ore;
these planes, when separated, are
the slickensides of the mineralogist.
The edges of the strata on the sides
of faults frequently present that
polished appearance known to miners
under the name of * slickensides.' "

SLOTH. The Bradypus of Linnasus,

S M A

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SOL

the only existing genus of Tardi-
grada.

SMALT, (smalto, It. schmalte, Germ.)
Powder-blue, a vitreous substance
obtained by melting zaffre, silex,
and potash together,
SMAKA'GDITE. The name given by
Saussure to diallage, from its eme-
rald-green colour.

SMA'HAGD. | (from fffidpa^Sos, Gr.)
SMA'BAGDUS. j The emerald. See

Emerald.

SOAP EOCK. | Names given to a kind
SOAP STONE. ) of steatite, in conse-
quence of its soapy feel. Soap rock
is so tender that it may be cut as
easily as new cheese. Its colour is
a pearly white or grey with red and
blue veins, and when pure is semi-
transparent. On coming out of the
quarry, it may be kneaded like a
lump of dough, but after having
been exposed to the air for some
time, it becomes friable ; it possesses
the soapy feel in the highest degree.
It is used in the manufacture of
porcelain. Klaproth gives the fol-
lowing as the analysis of soap rock:
silica 48-00, magnesia 20-50, alu-
mina 0'14, iron 0-01, water 15-50.
SO'DA. (soda, sode, soude, Germ.)
Mineral fixed alkali, found native
in some situations, but generally
obtained from the combustion of
marine plants, more particularly of
the salsola soda. " Soda," says De
la Beche, "is found in schorl, and
certain hypersthene rocks, in some
eurites, in trachytes, pitchstones,
basalts, and some diallage rocks.
It is found in greatest abundance
diffused through the waters of the
ocean."
SO'DA FE'LSPAB. Another name for

albite. See Allite.
SO'DALITE. (from soda, and X/0os,
Gr. stone.) A sub species of lapis
lazuli. The name sodalite has
been given to this mineral from the
large proportion of soda which it
contains, being 25 per cent. Its
constituents are silex 36 %0, alumine

32-0, soda 25'0, muriatic acid 6-7,
oxide of iron 0-2. It is found in
Greenland and Vesuvius. It occurs
massive, and in dodecahedrons with
rhombic faces. Colour green, of
different shades. Structure foli-
ated; fracture conchoidal. Specific
gravity 2'37. It is infusible.
SO'DIUM. One of the simple or ele-
mentary bodies. Sodium is the
metallic basis of soda, and, like
potassium, was discovered by Sir
H. Davy in 1807. It has the
appearance of silver, or of lead,
and is both ductile and malleable.
Its specific gravity is 0'97, conse-
quently it is lighter than water.
When united with oxygen in the
proportion of 23-3 by weight to 8
oxygen, it constitutes soda.
SOIL, (sol, Fr. souk, It.) The name
given to that superficial accumu-
lation of various substances which
lies upon the surface of the globe,
and covers the rocks below ; it is
also called earth, mould, loam, &c.
Its depth is irregular, from a few
inches to several feet.
SOLA'NOCRINITES. A genus of Kadi-
aria, three species of which have
been determined by Gold fuss and
Munster; these have been found
in the oolitic group of Germany.
SOLATIUM. A genus of fossil and
recent depressed, conical, nearly
discoidal, umbilicated, marine, uni-
valve shells, belonging to the
family Turbinacea. Recent solaria
are littoral shells, found on rocks
and weeds, and belong to tropical
seas.

SO'LEN. A genus of marine bivalves,
found on sandy beaches, wherein
it burrows vertically, and lies con-
cealed at a depth of about six
inches, when the tide leaves the
beach dry. The shell is bivalve,
oblong, equi valve, inequilateral,
open at both ends ; hinge with a
subulate reflected tooth, often
double, and not inserted in the
opposite valve.

SOL

[ 409 ]

SPA

SOLENE'LLA. A genus of bivalve con*
chifera, established by Sowerby,
belonging to the family Arcacea.

SO'LENITE. A fossil solen. Fragments
of solenites are found in the Essex
cliffs.

SOLE^TES. A genus of plants of the
Algae tribe, found fossil in the
Jurassic or Oolitic rocks.

SOLFATA'RA. The name of an extinct
volcano near Puzzuoli, which con-
stantly emits aqueous vapour, and
sulphureous and muriatic exhala-
tions. The word solfatara is now
applied to any volcanic vent emit-
ting sulphureous, muriatic, and
acid vapours or gases. Solfataras
are usually considered as semi-
extinct volcanoes, emitting only
gaseous exhalations and aqueous
vapours; but there can be no
certainty that they may not again
become active. According to Dr.
Daubeny, sulphuretted hydrogen
and a small quantity of muriatic
acid are contained in the steam
which rushes out of the fumeroles
at the solfatara near Naples. Sol-
fataras, variously modified, are by
no means rare in volcanic countries.

SOLIDU'NGULOUS. (from soltdus, solid,
and ungula, a hoof, Lat.) Having
the hoof whole and undivided, as
in the horse.

SO'LITABY. (sotitarius, Lat.)

1 . In botany, applied to peduncles
when there is only one on the
same plant, or when they stand
singly in the same place ; to seeds,
when there is only one in a pericarp.

2. In conchology, applied to a
single tooth.

SO'MMITE. The name given by Jame-
son to the mineral called by Haiiy
Nepheline,

SO'RDAWALITE. An earthy mineral of
a greyish or bluish-black colour,
massive, and without any traces of
cleavage. It was first discovered
by Nordenskoild, near the town of
Sordawala in Finland, whence its
name.

SPALACOTHE'EITTM. A genus of fossil
mammifers, of the upper oolite
beds, and so named by Prof. Owen.

SPAR, (spathy Germ, spath, Fr. terme
de mineralogie, emprunte de VAlle-
mand. Quelques uns disent,^ spar.}
In mineralogy, a name given to
those earths which easily break
into rhomboidal, cubical, or lami-
nated fragments with polished sur-
faces. Spar constitutes the sixth
order of the second class in the
natural history system of mineral-
ogy. Spar is not metallic; its
streak is white, grey, brown, or
blue. Hardness from 3*5 to 7*0.
Specific gravity from 2-0 to 3'7. As
the term spar is applied to stones of
different kinds, without any regard
to the ingredients of which they
are composed, an additional term
must necessarily be employed to
express the constituent parts as
well as the figure; for instance,
calcareous spar, gypseous spar,
adamantine spar, cubic spar, brown
spar, &c. &c. The term spar is
sometimes applied to quartz.

SPA'RRY I'RON. The fer oxide car-
bonate of Haiiy ; spath eisenstein
of Werner; fer spathique of
Brongniart; sparry iron-stone of
Jameson; sparry iron-ore of Kir-
wan. Carbonate of iron. It is
of a yellow, grey, brown, or black
colour; occurring crystallised in
rhombohedrons, or in laminated
and lamellar masses. It is found
in metalliferous veins, as well as in
common veins, in primary, transi-
tion, and secondary rocks. It con-
sists principally of protoxide of
iron and carbonic acid ; some spe-
cimens yielding manganese and
lime; others, magnesia, oxide of
manganese, and lime, but in very
small proportions. Sparry iron is
a valuable ore, from the facility
with which it may be converted
into excellent steel. It is, from
the last circumstance, sometimes
called steel ore.

2 G

SPA

[410]

S P E

SPATA'NGUS. A genus of echini^ of
the section Cor marinum, belonging
to the class Pleurocysti. It is
characterised by the bilabiated
mouth being in the third region of
the axis of tho base, and the anus
in the side of the truncated ex-
tremity. There are a great many
species of the genus. The shell of
the spatangus is oval, possessing
a great number of spines, by the
action of which it buries itself in
the sand. Fossil spatangi are very
abundant in the chalk formation.

SPATHE. (spatTia, Lat.) In botany,
a kind of bractea ; a large coloured
bractea which envelopes the princi-
pal axis of sessile flowers ; it forms
a sort of hood or sheath, opening
longitudinally, at some distance
from the flower ; the arum, calla,
&c. are examples.

SPA'THIC. In mineralogy, lamellar ;
foliated.

SPA'TTTLATE.

1. In botany, applied to leaves
shaped like a spatula or battledore,
having the upper part of a roundish
figure, the base tapering and
linear.

2. In conchology, applied to shells
which are rounded and broad at
the top, and becoming narrower
below.

3. In entomology, applied to the
figure of insects, when commencing
with a narrow base, gradually
widening by the lateral margins
sloping out, and terminated at the
extremity by a sudden straight
line.

SPE'CTES. (species, Lat.)

1. That which is predicated of
many things as the whole of their
essence.

2. In mineralogy, a species may
be defined, a collection of minerals,
which ^ are composed of the same
ingredients, and combined in the
same proportions.

3. In entomology, a group of
natural bodies which agree together

in all their essential, unchangeable
characters. The idea of species
comprises in it a congruency, that
is to say, not a mere conformity,
but also a resemblance of its indi-
viduals. Species is the lowest of
all the systematic groups, and con-
sequently, the most fixed and
conformable.

4. In botany, according to Jussieu
and others, a species is a combi-
nation of individuals alike in all
their parts. De Candolle makes it
" a collection of all the individuals
which resemble each other more
than they resemble any thing else ;
which can by mutual fecundation
produce other individuals; and
which reproduce themselves, by
generation, in such a manner that
we may from analogy suppose them
all sprung originally from one
single individual."

"What is a species? has long
been a questio vexata among biolo-
gists. If, however, we adopt the
idea of a species being the descen-
dants of a single pair, successive
generations of their species being
possible among those descendants,
and them only, we shall find the
facts of the distribution of species
harmonize well with this idea."—
Jukes.

SPEC'IFIC GRA'VITY. As this is a term
extremely common and in constant
use in mineralogy, it may be de-
sirable to define it. " The specific
gravity of a body is its weight,
compared with that of another
body of the same magnitude. Thus,
if a cubic foot of water weigh 1000
ounces, and a cubic foot of iron
7000 ounces, their comparative
weights or specific gravity are as
1000 : 7000, or as 100 : 700 or as
10 : 70, or as 1 : 7."— Phillips.

SPHA'GNOUS. Mossy.

SPE'ETON CLAY. A member of the
Lower Cretaceous or Neocomian
series. Its exact position is re-
garded as still uncertain. Prof.

S P E

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S P I

E. Forbes placed it at or below
the base of the Lower Greensaud.

SPECULAR, (speculum, Lat. a mirror.)
Any body which presents a smooth
and brilliant surface, and which
reflects light.

SPHAGO'DUS. (slaughtering or mur-
dering tooth, from ff^aryrj and oSovs
Gr.) The name given by M.
Agassiz to a genus of ichthyolites
found in the Tipper Ludlow rocks.

SPHA'GNUM PALTJ'STRE. A species of
moss, generally constituting a large
portion of the entire mass of peat
bogs. The sphagnum palustre has
the property of throwing up new
shoots in its upper part, while its
lower part decays, and from this
circumstance it mainly contributes
to the formation of beds of peat.

SPHERE, (sphc&ra, Lat. o-0a?/>a, Gr.)
A solid, generated by the revolu-
tion of a semicircle abont its dia-
meter, which remains fixed; a
globe ; an orbicular body ; a body
of which the centre is at the same
distance from every point of the
circumference; such a solid body
that all lines drawn from its centre
to its surface are equal. The lines
are called radii.

SPHE'RICAL. (sjpherique, Pr. sferico,
It.) Round; orbicular; globular;
Having all its diameters equal.

SPHERI'CITY. Roundness; globosity.

SPHE'ROID. (from afia'ipa, a sphere,
and etdoe, likeness, Gr.) A solid
body approaching to the form of a
sphere. A spheroid may be either
oblate or prolate ; an oblato sphe-
roid resembles an orange, having
its poles flattened, such is the form
of the earth and planets ; a prolate
spheroid has its poles drawn out,
and its form somewhat resembles
an egg.

SPHERO'IDAL. Having the form of a
spheroid, whether oblate or prolate.

SPHENO'PTERIS. A very beautiful and
delicate subgenus of fossil ferns or
filicites, described by Brongniart.

SPHE'RTJLE. (spharula, Lat.) A little
globe ; a globule.

SPHI'NCTER. (from <r0/7<yw, Gr. to
contract.) The name given to
certain muscles whose office it is to
contract the part in all directions,
drawing it together as the mouth
of a purse is contracted by a cir-
cular string.

SPI'DER. The different species of spi-
ders compose the genus Aranea, or-
der Pulmonariae, class Arachnides.
The male spider possesses four pairs
of legs, the female five, the addi-
tional pair enabling her to carry
her eggs. The legs are composed
of seven joints, the two first form-
ing the hip, the third the thigh,
the fourth and fifth the tibia, the
sixth and seventh the tarsus. The
feet are spread out in diverging
rays, so as to include a wide circle,
and afford an extensive base of
support ; they terminate in two,
or, sometimes, in three hooks. In
front of the head are placed mem-
bers resembling feet, having affixed
to them, or terminating in, a move-
able hook, or pincers, flexed infe-
riorly, underneath which is a mi-
nute opening that permits exit to
a venomous fluid contained in an
adjoining gland. By the injection
of this poisonous fluid the common
spider of this country is able to kill
a fly in a few minutes, and the
large spider of South America can,
by the same means, destroy the
smaller vertebrated animals, and
produce, even in man, severe con-
stitutional disturbance. The greater
number of species possess a curious
apparatus for spinning threads, and
for constructing nets, for the entan-
glement of flies and small insects.
This net, or web, is as various as
the species, each species construct-
ing its own peculiar form of net;
in addition to the principal web,
which is spun out for the capture
of small insects, the spider fre-
quently constructs a smaller one,

p I

[412]

S P I

both as a residence and a place of
ambush. Between these two con-
structions there is placed a thread
of communication, and no sooner
is the struggling insect involved in
the meshes of the larger net than
the vibrations of this communica-
ting thread afford information to
the concealed spider, who instantly
rushes towards his victim and en-
deavours to destroy it, by piercing
it with his dart and infusing into
the wound his poisonous fluid. The
web is produced by a double series
of spines, opposed to each other,
and planted on a prominent ridge
of the upper side of the metatarsal
joint, or that usually regarded as
the first joint of the foot of the
posterior legs next the abdomen.
These spines are employed as a
carding apparatus, the low series
combing, or extracting the ravelled
web from the spinneret, and the
upper series, by the insertion of its
spines between those of the other,
disengaging the web from them.

Fossil remains of spiders exist in
strata of very high antiquity.

SPIKE, (spica, Lat.) In botany, a
species of inflorescence, in which
the flowers stand sessile along a
common peduncle, and are either
placed alternately and crowded to-
gether, or in separate groups ; the
plantain, lavender, corn, &c., afford
examples.

SPI'KELET. In botany, the term ap-
plied to a subdivision of a spike,
forming, as it were, a small spike.

SPINE, (spina, Lat. epine, Fr. sp'ma, It. )

1. In anatomy, the vertebral co-
lumn or back-bone of vertebrated
animals.

2. In botany, a sharp point, or
thorn; the spines of plants differ
from prickles, inasmuch as they
proceed from the wood of the plant,
whereas a prickle comes from the
bark only, and they are distin-
guished by their woody vascular
centre.

3. In zoology, a thin pointed spike.
Some of the spines of fishes are
simply imbedded in the flesh of
the animal, and attached to mus-
cles; others are articulated with
bones which lie beneath them.

4. The word spine is occasionally
used to signify a ridge.

The fossil spines of various fishes
are found in strata from the grey-
wacke series to the chalk inclusive ;
they have obtained the name of
ichthyodorulites.

SPI'NELLE. } (spinelle, Fr.) A species
SPI'NEL. ) of corundum both of an
octahedral and dodecahedral form.
Some mineralogists place spinel in
the Ruby family. Its colours are
red, black, blue, brown, yellow,
and white. It occurs in regular
crystals, and, occasionally, in
rounded grains : when crystallized,
it is found either in regular octa-
hedrons, occasionally having their
edges replaced, or in macles, pre-
senting very different forms. It
scratches quartz, its hardness being
= 8. Its structure is usually fo-
liated, with laminae parallel to the
faces of the octahedron. Specific
gravity from 3*5 to 3*8. It is in-
fusible before the blow-pipe, and
intense heat does not even deprive
it of its colour. It consists of
alumina 82-47, magnesia 8'78,
chromic acid 6.18, loss 2 '5 7.
Sometimes its colouring matter is
oxide of iron instead of chrome;
the red specimens containing chro-
mic acid; the blue, protoxide of
iron. The spinelle ruby is a sub-
species, of a scarlet colour; the
rose-red specimens are termed Ba-
las rubies ; the yellow, or orange-
red, spinel is called Rubicelle; and
the violet coloured, Almandine
ruby. Spinel ranks as a precious
stone, and is worked by the lapi-
dary for ornamental purposes. As
a species, spinel was first estab-
lished by Rome de Lisle and Wer-
ner, and by them separated from

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sapphire, with which it had pre-
viously been confounded. It is
principally met with in Ceylon,
Siam, Pegu, and other eastern
countries ; it also occurs in drusy
cavities, together with Ceylanite,
Vesuvian, &c.

SPINE'LLANE. A variety of dodeca-
hedral zeolite. A mineral of a
plum-blue or blackish- brown co-
lour, found on the banks of the
river Laach, near Andernach. It
occurs in hexahedral prisms, ter-
minated by three-sided summits,
whose faces stand on alternate, but
different, lateral edges at each ex-
tremity.

SPI'NY. } Having spines, thorns, or

SPI'NOTJS. j points.

1. In botany, applied to plants
possessing thorns or spines ; also to
leaves, the margins of which are
beset with thorns.

2. In anatomy, applied to certain
processes of bones.

SPIRE, (spira, Lat.) That part of a
body which shoots up to a point.
In conchology, the spire of uni-
valve shells consists of all the
whorls except the lower one, which
is termed the body. The spire is
a prominent feature in univalve
shells, and upon its being elevated,
depressed, &c., depends much of
the generic and specific definition.
There are several kinds of spire;
the depressed spire, when the spire
is very flat; the involuted spire,
when the whorls are concealed in
the inside of the first whorl, as in
the nautilus; the reversed spire,
when the whorls turn in the con-
trary direction to a right-handed
screw, &c.

SP^IFEK. ) (from spira, a spire, and
SPIIU'FERA. ) fero, to bear, Lat.) A
genus of bivalve shells, distin-
guished from terebratula by its
very extraordinary internal spiral
processes or cones, of which there
were two, and from which it ob-
tains its name. The genus spirifer

appears to be met with, in the
descending series, first in the lias.
It is in the carboniferous limestone
that Spiriferae most abound, not
fewer than twenty species having
been determined as occuring in
that deposit. Deshayes recom-
mends the entire suppression of the
genus Spirifer, stating that all the
species may be referred either to
Producta or Terebratula. Spiriferse,
which are met with in great abun-
dance in the grauwacke and car-
boniferous series, appear to have
become extinct during, or immedi-
ately after, the deposition of the
lias, above which not any have been
discovered.

SPIEOLI'NA. A genus of microscopic
foraminiferous multilocular uni-
valves, described by Lamarck, who
discovered several species of them
in the fossils of Grignon.

SPIRO'RBIS. A genus of shells belong-
ing to the family of the Serpulacea.
A familiar example of spirorbis is
afforded in the common, small,
white, coiled shell so frequently
seen upon the shell of the lobster.
The spirorbis is found on sea- weed,
shells, &c.

SPI'RULA. (from spira, Lat.) Both
a recent and a fossil shell. A genus
of multilocular shells, partly spiral
and partly straight, the whorls
being arranged in a discoidal form,
and separate from each other ; the
last turn being elongated, and con-
tinued in a straight line. The si-
phunculus, instead of being mem-
branous, is formed by one con-
tinuous shelly tube. It appears
that the spirula, notwithstanding
it possessed a siphuncle, was, alto-
gether or in part, an internal shell.
The living spirula is an inhabitant
of tropical seas; it floats on the
surface of the ocean.

SPI'RULITE. A fossil spirula. Spiru-
lites are sometimes termed lituites,
from their supposed resemblance to
a bishop's pastoral staff.

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SPLE'NDENT. (splendens, shining, Lat.
splendente, It.) 1. In mineralogy, a
term applied to metals as regards
their degree of lustre. A mineral
is splendent when perceptible in
full day-light at a great distance,
as in highly polished metals.
2. Applied to any colour which
possesses a metallic splendour.

SPLENT COAL. } An impure variety of

SPLINT COAL. ) cannel coal, occur-
ring in Scotland.

SPLI'NTEEY. In mineralogy, a term
applied to a particular fracture of
minerals. The fracture is called
splintery when the surface, pro-
duced by breaking a mineral, is
nearly even, but exhibits little
splinters or scales, somewhat thick-
er at one extremity than the other,
and still adhering to the surface by
their thicker extremities.

SpLfNTEEY HOENSTONE. The Splittri-

ger Hornstein of Werner. Splin-
tery hornstone is a subspecies of
hornstone, occurring both massive
and crystallized. It is infusible,
per se, before the blow-pipe. Its
colours are various, principally
grey, red, and green. For a fur-
ther description, see Hornstone.

SPO'DTJMENE. (from O-TTO^OW, Gr. in
cinerem redigo.) The Triphane of
Haiiy ; Spodumene of D' Andrada.
A rare mineral of a greenish-white
or gray colour ; occurring massive,
and in large granular concretions.
Spodumene has been found in the
iron-mine of TJton, in Sweden, and
in primary rocks in Ireland. Ac-
cording to the analysis of Yauque-
lin, it consists of silica 64 '4, alu-
mina 24'4, potash 5, lime 3, oxide
of iron 2'2.

SPO'NDYLTJS. A genus of rough,
slightly- eared, inequivalved, ma-
rine, bivalves, with unequal beaks ;
hinge with two recurved teeth, se-
parated by a small hollow. Spon-
dyli are found only in the ocean,
attached to rocks, corals, &c. : they
are remarkable for their spines, and

the richness of colouring of the
shells. They are eaten like oysters.
Lamarck has described one spe-
cies as occurring fossil in the neigh-
bourhood of Paris, and very fine
fossils are found in Tuscany.

SPONGE, (anoxia, Gr. spongia, Lat.
eponge, Fr. spiigna, It.) This word
is pronounced, and frequently writ-
ten, spunge. A porous marine
substance found adhering to rocks,
formerly supposed to be a vegetable
production, but now classed among
the zoophytes: it is soft, light,
porous, and easily compressible,
readily imbibing fluids, and there-
by distending. " The existence of
fossil sponge in the transition or in
the mountain limestone," says Par-
kinson, "has not been ascertained,
or in the different beds of the lias
formation ; but the tenuity, in ge-
neral, of its substance^ and the
nature of the matrices in which it
has been sought, may perhaps oc-
casion its concealment."

SPO'NGIFOEM QUAETZ. The name given
to a white or grey, porous, variety
of quartz, so light as to swim on
water, and called also Floatstone.

SPONG'IADJE. An order of the class
Astomata, sub-kingdom Protozoa,
and divided by Pictet into three
families; Spongidse, Clionidse, and
Petrospongidas.

SPO'NGIOLE. In botany, an organ
situated at the extremity of the
root, and thus named from its
peculiar texture. It is by the
spongioles that plants are enabled
to absorb. They are constructed of
common cellular spongy tissue, and
they imbibe the fluids which are
in contact with them, partly by
capillary action, and partly, also,
by a hygroscopic power.

SPO'EULE. (from aTropa, a seed, Gr.)
The organ of reproduction in cryp-
togamic plants. Ferns are increased
by minute bodies, called sporules ;
these are produced either on the
backs, or in the axillse of the fronds,

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and on other parts. The organs of
reproduction in mosses consist of
sporules, contained within an urn
or theca, placed at the top of a thin
stalk. In lichens, the organs of
reproduction are sporules.

SPRINGS OF WA'TER. All permeable
strata receive rain-water at their
surface, whence it descends until it
is arrested hy an impermeable
subjacent bed of clay, causing it to
accumulate throughout the lower
region of each porous stratum, and
to form extensive reservoirs, the
overflowings of which on the sides
of valleys constitute the ordinary
supply of springs and rivers. The
water, however, which descended
from the atmosphere in the form of
rain, having passed through the
various strata, does not re-issue in
the same condition. Rain-water
contains carbonic acid ; in passing
through the strata it absorbs oxide
of iron, lime, &c., and on issuing in
the form of springs it loses its
excess of carbonic acid, and again
deposits carbonate of iron, &c.
" Springs are seldom or ever quite
pure, owing to the solvent property
of water, which percolating through
the earth, always becomes more or
less charged with foreign matter.
Carbonate, sulphate, and muriate
of lime, muriate of soda and iron,
are frequently present in spring
waters. Some are more highly
charged with these and other sub-
stances, such as carbonate of mag-
nesia and even silica, than others,
and have hence obtained the name
of mineral springs. Many thermal
springs contain silica, though this
substance is of exceedingly difficult
solution. Springs usually possess
one particular average temperature,
generally identical with that of
the ground through which the
particular spring passes."

SQUA'LOID. (from squalus, a shark,
Lat. and e?£o<?, resemblance, Gr.)
The squaloid, or third division of

fossils of the family of sharks,
appears for the first time in the
chalk formations, and extends
through all the tertiary deposits to
the present period.

SQTJA'LUS. The name given by Lin-
na3us to the true shark.

SQUA'MOSE. ') (sguamosus, Lat.) Sca-

SQTJA'MOTJS. j ly ; covered with scales.

SQA'RROUS. (from squarra, roughness
of skin, Lat.)

1. In conchology, consisting of
scales spreading every way, or
standing upright, and not parallel
with the plane.

2. In botany, applied to parts with
scales widely divaricating.

STAGONOLE'PIS. A genus of ichthyo-
lites of the old red sandstone.

STA'LACTITE. (oraXa/cT^, from ora-
Xa^w, Gr. to drop or distil ; statac-
tite, Pr.) A concretion of carbo-
nate of lime pendent from the roof
of a cavern, and produced by the
percolation and dripping of water,
holding in solution, or super-satu-
rated with, carbonate of lime. The
mode of formation of a stalactite
resembles that of an icicle j the
water, as it slowly drips from the
roof, continually deposits upon the
pendent stalactite a small quantity
of its carbonate of lime, and thus
the stalactite increases in length
and bulk.

STA'LAGMITE. (from o-TaX^/io?, Gr.
stalagmite, Pr.) A concretion of
carbonate of lime produced by the
dripping of water holding in solu-
tion carbonate of lime. The dif-
ference between a stalactite and a
stalagmite is this: the former is
attached to, suspended from, and
formed at, the roof of a cave or
grotto ; the latter is formed upon
the floor : the stalactite generally
resembles a large icicle ; the stalag-
mite is an unshapen mass upon the
floor. It sometimes happens that
from the stalactite lengthening
downwards, and the stalagmite
increasing upwards, the two be-

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come united, and thus form a
column extending from the roof to
the floor.

STA'HEN. (stamen, Lat.) A consti-
tuent part of a flower, situated
within the corolla, consisting of
two parts, the filament and the
anther. The stamens are the male
organs of the plant. In the plural
the word is written either stamens
or stamina.

STA'NDARD. In botany, the upper
large petal of a papillionaceous
flower ; also called the banner.

STANNI'FEROTJS. (from stannum, tin,
and/m?, to bear, Lat.) Containing
tin; yielding tin; producing tin.

STAT/ROLITE. The name given by
Kirwan to the harmotome of Haiiy,
the cross-stone of Jameson ; kreutz-
stein of Werner. The composition
of staurolite, as described byCleave-
land, differs entirely from that of
staurotide. Staurolite contains,
according to some analyses, upwards
of twenty per cent, of baryta, and
no oxide of manganese ; whereas
staurotide contains no baryta, but
four per cent, of oxide of manganese.
Prof. Cleaveland assuredly does not
intend the same mineral in descri-
bing Staurotide and Staurolite,
nevertheless, I find most mineral-
ogists giving these two words as
synonymous. The reader, however,
must bear in mind that Harmotome,
or Cross-stome is not to be con-
sidered as Staurotide, although by
some authors Staurotide is regarded
as synonymous with Staurolite.

SiAtfBOTiDE. The name given by
Haiiy to prismatoidal garnet or
grenatite. The prismatoidischer
garnet of Mohs; the granatit of
Werner ; the grenatite of Jameson
and Brochant. This mineral, of a
reddish-brown colour, occurs crys-
tallized, in'^ four and six-sided
prims, sometimes intersecting each
other at right angles. Its primitive
form, under which it sometimes
appears, is a four- sided prism,

whose bases are rhombs with
angles of 129° 30' and 50° 30':
the reflection goniometer gives the
measurement of the angles 129° 20'
and 50° 40'. Its integrant parti-
cles are triangular prisms. Its
colours are reddish-brown to black-
ish-brown. Specific gravity from
3-3 to 3-9. Hardness from 7 to
7 §5. It feebly scratches quartz,
but does not yield sparks with
steel. Fracture uneven or imper-
fectly conchoidal. It consists of
silica, alumina, lime, and the oxides
of iron and manganese. It is found
in primary rocks only. It may be
distinguished from garnet by its
form and infusibility.

STEA'RIN. | (from aireap, Gr.) The

STEAEI'NE. j solid part of oil and
fatty matter. Fat is composed of
two constituent principles, which
Chevreuil distinguished by the
terms stearine and elaine.

STEAT'ITE. Veins of Steatite are very
plentiful in the serpentines of the
Lizard. Their colour varies from
white to yellow, green, and purple.
The veins of steatite have distinct
walls, and are as regular as most
true veins. Fragments of serpen-
tine and calcareous spar are some-
times found in them. Dr. Berger
considered steatite to bear the same
relation to serpentine that kaolin
bears to granite. Dr. Thomson
considers steatite to be a portion of
serpentine altered by the action of
water, or some other body. Sir
H. Davy regarded the veins of
steatite as mechanical deposits.
Steatite has four equivalents of
silica to three of magnesia.

STEEL. (stahl, Germ. From the
Chalybes, who had considerable
iron and steel works, has steel
derived its Greek name of ^aXu^
though some have thought to de-
rive the name of the people from
their works. The word chalybs
was adopted by the .Romans from
the Greeks, and is has passed into

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our own language in the adjective
chalybeate.) Iron combined with
carbon. The proportion of carbon
has, perhaps, never been accurately
ascertained ; but steel containing
one-sixtieth of its mass of carbon
is said to have the maximum degree
of hardness. The following are
some of the properties of steel: —
It is so hard as to be unmalleable
when cold ; it is brittle, resists the
file, cuts glass, affords sparks with
flints, and retains the magnetic
virtue for an indefinite length of
time. By being ignited, and after-
wards slowly cooled, it loses its
hardness. It fuses at 130° Wedge-
wood. When red-hot it is malle-
able. It is more sonorous than
iron, and may be hammered out
into much thinner plates. The
conversion of iron into steel is
effected by combining it with
carbon. This combination is per-
formed in three ways, by three
different processes, and the products
are distinguished by the names of
natural steely steel of cementation,
and cast-steel. Of these, the most
valuable is cast-steel, its texture
being the most compact, and it
admitting of the finest polish. The
manufacture of articles of steel,
says Mr. Babbage, affords a most
striking example of the value con-
ferred by human labour on the raw
produce of nature. The value of a
pound of crude iron is twopence.
This pound of iron, after having
been converted into steel, is manu-
factured into balance-springs for
watches. One of these springs
weighs ^ of a grain and sells for
twopence. After deducting for
waste, a pound of iron will make
fifty thousand springs, and the
twopennyworth of iron becomes
worth £416 13s. The value of
the charcoal is too minute to be
taken into the calculation.
STEL'NIIEILITE. A variety of iolite, a
mineral of a blue colour.

STE'LLA MARI'NA. The name employed
by Linck, on the authority of
Pliny, to signify the asteria or
star -fish.

STE'LLATED. (from stetta, Lat. a star.)
Having the fibres diverging all
round a common centre.

STELLE'RID-E. The name assigned by
Lamarck to the Linnsean genus
Asteria; of this genus Lamarck
has formed a family comprehending
four genera.

STELLE'EIDAN. An animal resembling
an asteria. Fossil stelleridans have
not been discovered in strata more
ancient than the muschel-kalk.

STE'LLITE. A fossil asteria or star-
fish.

STELLI'FE-ROUS. (from stella, a star,
and fero, to bear, Lat.) Having
stars, as some of the corallines.

STE'LLULAE. Having markings re-
sembling stars. The surface of the
tubipora, or organ-pipe coral, is
covered with a green fleshy sub-
stance, studded with stellular polypi.

STENEOSAU'ETJS. A genus of fossil
Saurians, with long and narrow
beaks ; thus named by M. Geoffrey
St. Hilaire. In the Steneosaurus
the arrangement of the nostrils was
nearly the same as in the gavial,
opening upwards, and of nearly a
semicircular form on either side.

STE'ENAL. (from sternum, the breast-
bone.) Pertaining to the sternum
or breast-bone.

STE'ENUM. (<rrepvov, Gr. sternum,
Lat.) The breast-bone. In the
human subject the sternum is di-
vided into three parts; in some
vertebrated animals it is formed of
nine elementary species, each pro-
ceeding from a separate centre of
ossification. "Few subjects in
comparative osteology," says Dr.
Roget, " are more curious and in-
structive than to trace the develop-
ment of these several elementary
parts in the different classes of
animals, from the rudimental states
of this bone as it occurs in fishes,
2 H

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to its greatly expanded conditions
in the tortoise and the bird, which
severally exhibit the most opposite
proportions of these animals."
STI'GMA. (a^ifia, Gr. stigma, Lat.)
In botany, the apex of the pistil ;
the stigma is variously formed,
being either a fine point, a round
head, or lobed; generally downy,
often hollow and gaping, and more
or less moist. Sometimes, though
there is only one style, there are
two or more stigmas ; when there
is no style, the stigma is sessile on
the ovarium.

STIGMA'BIA. A family of extinct fossil
plants of the coal formations. The
stigmaria was an aquatic plant,
inhabiting swamps or lakes, and,
as regards its external structure,
resembled the euphorbiaceaB. Frag-
ments of stigmariaB occur abundantly
in the coal shales. It appears to
have been dicotyledonous.

"Authors are by no means
agreed," says Sir H. De la Beche,
" as to what families certain genera
of fossil plants should be referred.
Thus M. Ad. Brongniart refers the
genus Stigmaria, very common in
the coal measures, to the family of
Lycopodiacea3 ; while Lindley and
Hutton consider that, if any exist-
ing analogy must be found, it is
with greater probability of accuracy
referrible to the Euphorliacece or
Cacte®, most probably to the for-
mer; a difference of considerable
importance, as upon it depends
whether the genus in question
belongs to the class cellurares, or to
the class vasculares. This difference
of opinion arises, no doubt, from
the obscurity of the subject, fossil
botany being beset with very great
difficulties; difficulties far beyond
those which attend the study of
fossil zoology, though the latter are
by no means either small or rare."
STI'GMATA. Spiracles from which the

tracheaa of insects commence.
STI'LBITE. (from <rnX/3w, to shine,

Gr.) Prom the degree of lustre
which it possesses. The radiated
zeolite of Jameson ; strahl- zeolite of
Werner ; prismatoidischer kuphon-
spath of Hohs. Stilbite is of a
white colour generally, sometimes
pure, at others shaded with grey,
yellow, or red. It occurs both
crystallized and massive. It is
splendent externally ; internally
shining and pearly. Translucent,
and sometimes transparent. Specific
gravity 2-2. Hardness 3-5 to 4'0.
It does not scratch glass. It con-
sists of silica 52*5, alumine 17*5,
lime 11-5, water 18'5. It occurs
in secondary trap rocks, in Scotland,
Norway, and in the Faroe islands.

STINK STONE. (Called also Swine-
stone.) The name given to a va-
riety of limestone, from the fetid
odour which it gives out on friction ;
a smell resembling rotten eggs. It
is the chaux carbonate e fetide of
Haiiy; the stinkstein of Werner.
It occurs in masses, either compact,
or having a granular or foliated
structure, frequently forming large
beds, or even whole mountains.

STIPE, (stipes, Lat.) In botany, the
stem or base of a frond ; a species
of stem passing into a leaf, or not
distinct from the leaf; the name
given to the stem of palm trees ; it
differs essentially in form, struc-
ture, and mode of growth, from
the trunk, increasing in length
only, and not in thickness. The
stem of a fungus is also called a
stipe, as is the thread, or slender
stalk, which supports the down,
and conncts it with the seed.

STI'PULA. | (from stipula, Lat.) In

STI'PULE. j botany, a membranous
leafy appendage, placed at that part
of the stem whence the leaf or
footstalk arises. Stipules vary Jin
number, being solitary or in pairs ;
in situation, being either external
with regard to the leaf or footstalk,
or internal, the internal sometimes
embracing the stem in an undivided

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tube ; in form, linear at the base,
or crescentic ; in attachment, con-
nected directly with the stem, or
with the petal; in direction, erect,
or variously reflected. Stipules
serve to protect the nascent leaves.

STOMATO'PODA. An order of the class
Crustacea; the animals belonging
to this order have the antenniferous
region of the head distinct from
the thorax.

STONE GALL. The name given by the
workmen to an oval or round mass
of clay, occurring in variegated
sandstone.

STONE-BOBEE. The name for a mollus-
cous bivalve which mechanically
perforates, or bores into, rocks.

STONE COAL. Another name for culm.
See Culm.

STEAMI'NEOUS. Straw-coloured; of a
yellow colour resembling that of
straw.

STEATIFICA'TION. The arrangement
of substances in strata or layers,
like the leaves of a book, one upon
another.

STBA'TIFIED. Arranged in layers or
strata, one upon another, like the
leaves of a book.

STEA'TTJM. (stratum, Lat. from ster-
no, to lay out, to spread.) A layer
of any deposited substance. The
term stratum is of general signifi-
cation, and independent of the
absolute thickness of the mass ; it
need never be used as a special
term of definition, but reserved for
general reasoning. Bakewell ob-
serves, " though the word stratum,
in its original language, and by
general acceptation in speaking of
rocks, denotes a bed, it is conve-
nient to restrict the term bed to a
stratum of considerable thickness ;
for such fyds are often subdivided
into several distinct minor strata,
and we cannot well describe a stra-
tified stratum." The true thickness
of a stratum is measured by a line
perpendicular to the upper and

under surface, let its inclination
be whatever it may.
STBEAK. (strich, Germ.) In miner-
alogy, that appearance of a mineral
which arises from its being scratched
by a hard sharp instrument. The
streak is said to be similar when the
colour of the powder produced by
scratching the mineral is the same
with the colour of the mineral itself;
when the colour varies, the streak
is said to be dissimilar. Streak
forms one of the physical or exter-
nal characters of minerals, and by
no means an unimportant one. The
particular hue of the powder of a
mineral is most easily obtained by
rubbing or streaking the specimen
on a slab of porcelain biscuit.
STUEPSI'PTEEA. (Kirby.) An order
of insects, parasitic animals, that
have two ample wings, forming the
quadrant of a circle, and of a sub-
stance between coriaceous and mem-
branous ; and two elytriform sub-
spiral organs, appendages of the
base of the anterior legs. Latreille
has given to this order the name
Rhipiptera.

STEEPTOSPO'NDYLTTS. (Reversed spine.)
The name assigned to an extinct
crocodilian reptile, and so named
because the vertebrae are arranged
in the spiral column in a position
the reverse of that which obtains
in all other reptiles of the same
osteological type; the convexity of
the vertebras being placed anteriorly,
whereas in the crocodile, &c., it is
in the opposite direction. — Mantell.
STBI'ATED. (strie, Fr.) Arranged in
fine lines running parallel to each
other, let the direction of the lines
be what it may. Marked with fine
thread-like lines, running parallel
to each other.

STRIKE, (slreich, Germ.) The line
of bearing of strata. The strike or
direction of strata is always at right
angles to their dip; if a bed dip
due north or south, its strike will
be due east and west.

S T R

[ 420

S T U

STEPPED AG'ATE. (See Ribbon Agate.}

STR'IPED JA'SPEB. The Band jaspis
of Werner. Quartz-jaspe onyx of
Haiiy. Called also Kibbon jasper.
This is a variety differing from
common jasper principally in the
arrangement of its colours, which
are various, and arranged in stripes,
veins, rays, and in curved, con-
centric zones. It occurs massive,
in whole beds. Specific gravity
from 2-44 to 2-55. Fracture flat
conchoidal. Opake. Being sus-
ceptible of a high polish, this variety
of jasper is used for ornamental
purposes. It is found principally
in the Uralian mountains of Siberia,
in Saxony, in Devonshire, and in
the neighbourhood of Edinburgh.

STRO'BIL. } (from strolilus, Lat.) In

STRO'BILE. ) botany, a pericarp formed
from an ament by the hardening of
the scales ; a catkin hardened and
enlarged into a seed-vessel; a seed-
vessel composed of ligneous scales.

STEOMA'TETJS. An ichthyolite, exhi-
biting much analogy with Zeus or
Chsetodon, and met with in the
metalliferous schists of Mansfield,
Thuringia, &c.

STRO'MBITE. A fossil strombus; a
petrified strombus. Strombites are
very rare: in the mountains of
Arragon, and in the Veronese, some
specimens beautifully preserved
have been discovered.

STRO'MBUS. The name given by Lin-
n&us to a genus of univalve, spiral,
marine, shells : aperture much di-
lated: lip expanding and produced
into a groove. Lamarck has divi-
ded this genus into two subgenera,
Strombus and Pteroceras. In some
of the shells of this genus the spines
are of great length, and are arranged
round the circumference of the base,
being at first tubular, and after-
wards solid, according to the period
of growth. In Turton's Linne,
fifty-five species of strombi are
described.

STEO'NTIA. } A mineral sometimes

STBO'NTIAN. ) transparent and co-
lourless, but generally with a tinge
of yellow or green. Hardness =
5. Specific gravity from 3*4 to
3-9. Texture, generally fibrous;
sometimes it occurs crystallized in
slender prismatic columns of va-
rious lengths. Its taste is acrid
and alkaline ; it converts vegetable
blues to green. The principal use
of strontian is to communicate a
beautiful red colour.

STEO'NTIANITE. Carbonate of stron-
tian. The Strontian carbonatee
of Haiiy ; Strontianit of "Werner ;
Strontiane of Jameson; Stronthi-
anite of Kirwan. A mineral first
brought to Edinburgh from the
lead-mines of Strontian, in Argyle-
shire, in the year 1787. It greatly
resembles carbonate of barytes, but
it is not poisonous.

STBO'NTIUM. The metallic base of
strontia. Strontium greatly re-
sembles barium in its appearance,
although it is, indeed, a very dif-
ferent substance. Strontium is
harmless, but barium and all its
salts are poisonous. The salts of
strontium communicate to flame a
fine red tinge ; those of barium, a
yellow.

STETJ'CTURE. (structura, Lat.)

1. A term used, in mineralogy,
to denote one of the characters of

-minerals. The structure of a min-
eral depends on the shape, size,
and arrangement of the minute
parts of which it is composed. It
is sometimes used synonymously
with fracture, but it is not correct
so to do, there existing a consider-
able difference between the two
terms.

2. The manner of organization of
animals and vegetables. The man-
ner in which the parts of an orga-
nized body are arranged among
themselves.

STU'FA. (stufa, It.) A jet of steam
issuing from a fissure of the earth.

STY

[421 ]

sue

In volcanic regions stufas are by
no means uncommon. The name
is taken from the Italians, who
thus apply it.

STYLE, (stylus, Lat.) In botany,
that part of the pistil which ele-
vates the stigma above the germen.
The style is not absolutely essen-
tial, and is sometimes wanting.
The style is a continuation of the
midrib, and constitutes a portion
of the pistil.

STYLI^A. The name of a genus of
lamellated polypifers, thus de-
scribed by Parkinson, "A stony
polypifer, formed of simple thick
masses echinated in the upper
part. Numerous cylindrical fasci-
cular tubes containing radiating
lamellae, with a solid axis ; the
solid styliform axes projecting be-
yond the tubes."

STYTHE. The name given by the
colliers to fire-damp.

SUB-A'PENNINE. A term applied
geologically to a series of strata, of
the older pliocene period. The
beds which have been termed sub-
apennine are composed of sand,
clay, marl, and calcareous tufa;
they are all tertiary deposites, and
abound in marine shells, of genera
and species which prove some of
them to be contemporaneous with
the crag deposit, and others of a
more ancient epoch : they rest un-
conformably upon the inclined beds
of the Apennine range. Brocchi,
an Italian geologist, gave to this
group the name it bears. The sub-
appenine beds have resulted from
the waste of the secondary rocks
which now form the Apennines,
and which had become dry land
before the older Pliocene beds were
deposited.

SUBLIMATION, (sublimation, Fr. sub-
limazione, It.) That operation by
which solids are, by the aid of
heat, brought into a state of vapour,
and again condensed into a solid
form. One of the hypotheses

proposed to explain the filling of
chasms in solid rocks with metallic
ores, is by a process of sublimation
from subjacent masses of intensely
heated mineral matter.

SUBSE'SSILE. In botany, applied to
leaves having very short footstalks.

SU'BSTANTIVE CO'LOTJES. Dr. Bancroft
divides colours into substantive and
adjective: those which he termed
substantive colours, communicate
their colour without the interven-
tion of some other substance : those
which he called adjective, require
the aid of a mordant or basis.

STJBTEBPOSI'TION. The order of ar-
rangement in which strata or rocks
are placed below each other, as
superposition is the order in which
they are arranged above one
another. Subterposition in the
plutonic, like superposition in the
sedimentary rocks, being, for the
most part, characteristic of a newer
age.

STJ'BTJLATE. (from subula, an awl,
Lat.) Awl- shaped.

1. In botany, applied to leaves,
when thickest at the base, and
gradually tapering towards the
point.

2. In conchology, applied to shells
tapering gradually to a point.

3. In entomology, a long thin cone
softly bent throughout its whole
course.

SU'CCLNITE. (from succinum, amber,
Lat.) A mineral of an amber-
yellow colour, thus named by
Bonvoisin. It occurs in small
rounded masses about the size of a
pea. Some mineralogists refer
succinite to the idocrase; others, to
the garnet ; by some it is deemed
an amorphous variety of topazolite.

SU'CCTJLENT. (succulentus, Lat. succu-
lent, Fr. sug6sa, It.) Juicy ; full
of juice. A term applied to plants
with a soft and juicy stem, as
distinguished from those called
ligneous.

SFCTO'BIA. A class of animals belong-

S U D

[ 422 ]

S IT P

ing to the sub-kingdom Diplo-
neura or Helminthoida. Cuvier
placed Suctoria in his placoid order,
but by the more recent classification
of Muller and Owen they have been
removed from that high order and
carried down to the lower point in
the scale, which their inferior
standing so obviously renders the
natural one.

ST/DES. (sudes, Lat. a spear.) A
class of spines comprising several
genera, as Sudes villarum, Sudes
for tali tiorum, &c.

SUFFOLK CEAG. A marine deposit of
the older pliocene period. It con-
sists of beds of sand and gravel,
abounding in shells and corals.

SU'LCATED. (from sulcus, a furrow,
Lat.) Furrowed ; grooved.

1. In botany, applied to stems
marked with broad deep lines;
also to leaves having broad, deep,
parallel lines.

2. In conchology, applied to shells
that are deeply furrowed, or marked
with ridges or broad furrows.

S'ULCUS. Plural sulci. A broad
furrow or groove.

SULPHATE, (from sulphur.) A com-
bination of sulphuric acid with any
salitiable base.

SULPHITE. A combination of sul-
phurous acid with any salifiable
base.

SU'LPHUR. (sulphur, Lat. sou/re, Pr.
%6lfo, It.) One of the simple or
elementary substances, and a non-
conductor of electricity. It is of
different shades of yellow, and
occurs either in masses or crystal-
lized. Specific gravity from l-9
to 2'1. By friction it acquires
negative electricity. It is very
brittle and friable. Its equivalent
number is 16'1 ; its symbol, S.

SU'LPHURET. A combination of sul-
phur with a metallic base ; as sul-
phuret of iron.

SU'LPHUBET OF IRON. Iron pyrites.
This is very commonly found in
irregular and subglobular nodules

and masses, in the chalk formation.

SU'MMIT. (summitas, Lat. sommet, Pr.)
In conchology, the most elevated
point of the shell in which the
hinge is placed.

SUPERFI'CIES. (superficies, Lat. super-
fide, Pr. c'est lonyeur ei largeur sans
profondeur.) The surface only of a
body; the exterior part.

STJP'ERIOR ORDER. By some geolo-
gists it has been proposed to place
all the formations above the chalk
in an order to be named the " Su-
perior Order." The superior order
may be deemed synonymous with
the tertiary, or newest floetz rocks.
In the arrangement thus proposed
the division of all the formations
will be as follows.
1. Superior order ; the same as the
tertiary. 2. Supermedial order,
comprising the chalk and all other
formations downwards to the mag-
nesian limestone inclusive. 3.
Medial order, comprising the coal
measures, the carboniferous lime-
stone, and the old red sandstone.
4. Submedial order, synonymous
with the transition, comprising the
roofing slate, &c. 5. Inferior or-
der, consisting of mica, slate, gneiss,
granite, &c., &c.

SUPERME'DIAL ORDER. This class in-
cludes, generally, all the secondary
formations more recent than the
great coal deposit, and between it
and the tertiary, supra-cretaceous,
or newest floetz class. This series
of strata comprises distinct groupes
well marked from each other, and
therefore entitled to the name of
separate formations. The super-
medial order admits of four prin-
cipal divisions. 1 . The chalk for-
mation. 2. The series of ferrugi-
ginous sands, including, and divided
by, theWealden. 3. The series of
oolites, including and terminating
with the lias. 4. Prom the lias
downwards to the coal, comprising
the new red sandstone and the
magnesian limestone.

SUP

1423 ]

S

SUPERPOSITION. The order in which
bodies are placed upon or above
other bodies, as more recent strata
upon those that are older ; second-
ary rocks upon primary; tertiary
upon secondary, &c., &c. The
order of superposition of rocks is
never reversed, unless it be by
volcanic agency, when rocks may
be forced from below and thrown,
as it were, upon those which, in
the usual order of superposition,
would be above them. Beds, or
strata, may be altogether wanting,
but whereever similar beds occur
together, the order of superposition
is never inverted. Thus the Wealden
deposites are never found above the
chalk ; the chalk is never found above
the London clay; the London clay
is never found above the crag: nor
do we meet with the chalk under
oolite, the lias under the red sand-
stone, or the coal under the grey-
wacke. The order of superposition
alone does not form a certain cri-
terion of the ages of rocks, but
when coupled with their zoological
contents, the two connected may be
considered the only safe criterion.

SUPRA-CRETA'CEOUS. (from supra, above,
and cretaceus, chalky, Lat.) Above
the chalk ; formations more recent
than those of the chalk. The
supra-cretaceous deposites are very
commonly termed tertiary. This
is, however, a name exceedingly
objectionable, as it would imply
that there were three great classes
of rocks possessing marked charac-
teristic distinctions, and that the
deposites above the chalk consti-
tuted the third of such classes.
The supra- cretaceous rocks consti-
tute a large portion of the dry land
of Europe, among the lowest of
which, in Western Europe, are those
of the London and Paris basins.
Bakewell considers the term supra-
cretaceous, or, as he writes it,
super- cretaceous, to be peculiarly
inappropriate, and adds, " if a new

name were necessary, post-creiace-
ous should have been chosen."
The supra-cretaceous rocks are ex-
ceedingly various, and contain an
immense accumulation of organic
remains, terrestrial, freshwater, and
marine. This group has lately
been shown to approach, more
closely than was supposed, to the
existing order of things on the one
side, and to the cretaceous group
on the other.

SU'RTURBRAND. A name given to
Bovey coal, or brown coal.

SU'SSEX MA'RBLE. A member of the
Wealden group; occurring in
layers varying from a few inches
to upwards of a foot in thickness,
the layers being separated by seams
of clay, or loose friable limestone.
It is a fresh-water deposit, and
contains in great abundance shells
of paludinse, a genus of fresh-water
univalves. It is of various shades
of grey and bluish-grey, mottled
with green and yellow ; it bears a
high polish, and is used extensively
for architectural and ornamental
purposes. There is historical proof,
says Dr. Mantell, of its having been
known to the Romans, and in the
early Norman centuries it was
much sought after, and applied,
when cut into small shafts of pillars,
which were placed in the triform,
or upper arcades, of cathedral
churches, as at Canterbury, Chi-
chester, &c. The archiepiscopal
chair of Canterbury cathedral is
formed of Sussex marble.

SU'TURE. (sutura, a seam, Lat.) A
seam ; the junction of the bones of
the head by an irregularly jagged
zig-zag line.

SWAL'LOW. The name given to a
chasm or hollow, commonly occur-
ring in the mountain or carbonifer-
ous limestone, in which a stream of
water is engulphed. The stream
or river reappears after a certain
subterranean course.

SWI'LLEY. A provincial term for a

S

L

SYS

coal-field of very limited extent.

SWINE-STONE. The name given by
Earwan to fetid carbonate of lime,
or stink-stone.

SY'LVANITE. Native tellurium.

SY'MON FAULT. A local term applied
to the tapering off of coal seams.
The coal not unfrequently tapers
away and disappears amid the
shales and sandstones, constituting
what are locally termed "Symon"
faults.

SY'MPHYSIS. (o-v/ix^Wt?, Gr. from
avfji^via to grow together.) A term
used in anatomy to denote a parti-
cular form of union of two bones.
Bones united by symphysis have no
manifest motion.

SY'NCHRONAL. } (from avv, the same,

SYNCHRONOUS. ) and ^p6vo<s, time
or age. Gr.) Occuring at the same
period of time; simultaneous; of
the same age.

SY'NCLINAL LINES. Lines which form
ridges and troughs running nearly
parallel to each other.

SYNGENE'SIA. (from avv, with, and
rycWfft?, generation, Gr.) In botany,
the nineteenth class of plants in
Linnaeus' s artificial system. The
orders of this large class, five in
number, are founded on the cir-
cumstance of the florets of the
capitule being hermaphrodite and
unisexual, variously combined in
the disk and ray. The anthers are
united into a tube, and the flowers
are compound. The following are
the five orders composing the class
Syngenesia; they are determined
by the arrangement of their flowers,
and by the sex of their florets.

1 . Polygamia aequalis, where each
floret is perfect, being furnished
with stamens and pistils, and capa-
ble of bringing its seed to maturity :
the leontodon taraxacum, or dan-
delion, is a familiar example. 2.
Polygama superflua. The florets
of the disk perfect, those of the
margin having pistils only: the
anthemis nobilis, or chamomile, is

an example. 3. Polygamia frus-
tranea. Florets of the disk perfect
or united, those of the margin
neuter, or destitute of pistils as
well as of stamens. 4. Polygamia
necessaria. The florets of the disc
are male, of the ray female : the
garden marygold affords an illus-
tration. 5. Polygamia segregata.
Several florets, either simple or
compound, but with a proper calyx,
included within one common calyx :
the globe-thistle is an example. To
these five orders, some authors add
a sixth, namely, Monogamia, which
has the flowers separate, and not
crowded in heads.

SYNO'VIA. (from avv, with, like, and
wov, an egg, Gr. synovie, Fr.) A
glairy lubricating fluid contained
within the capsular ligament of
joints, serving the purpose of pre-
venting friction, and resembling the
white of an egg, whence its name.

SYNTHESIS, (avvdeai-s, Gr. from aw-
7101} pi, to join together; synthese,
Fr.) The act of joining; opposed
to analysis. Water is proved to
consist of oxygen and hydrogen by
analysis, that is, by decomposing
water and ascertaining its consti-
tuents; it may however be proved
to consist of oxygen and hydrogen
by synthesis, that is, by uniting the
relative proportions of oxygen and
hydrogen.

SYRINGODE'NDEON. The name given
by Count Sternberg to many species
of sigillaria, from the parallel pipe-
shaped flutings that extend from
the top to the bottom of their
trunks. These trunks are without
joints, and many of them attain
the size of forest trees.

SYSTE'MIC CLRCULA'TION. The circu-
lation of the blood through the
body generally, as distinguished
from that other circulation which
is confined to the respiratory organs
and the heart, or the respiratory
circulation.

SY'STOLE. (<™<7ToXr}, Gr. contraction,

SYS

[ 425 ]

T A L

systole, Fr.) A term used to signify
the heart's contraction. The two
movements of the heart are its
systole and diastole; by the systole
of the heart, or its contraction, the
blood is pressed out of the heart
and forced into the arteries; by
its diastole, the blood is received
from the veins into the heart.

SY'ZIGY. (from avfy<ytat Gr. con-
junction; syzygie, Fr.) A term
applied to the conjunction or oppo-
sition of a planet with the sun.
The syzygies of the sun and moon
occur at the time of full and new
moon; the tides are much increased,
and are called spring tides, in the
syzygies.

T

TABASHEE'E. A silicious secretion,
or concretion, found in the joints
of the bamboo : by some it has
been supposed to be the juice of
the plant inspissated and hardened.
It is remarkable on account of its
peculiar optical properties ; its re-
fractive power is between air and
water, namely 1*111. The finest
varieties reflect a delicate azure
colour, and transmit a straw-yellow
tint, which is complemental to the
azure. When it is wetted slightly
with a wet needle or pin, the wet
spot instantly becomes milk-white
and opaque. The application of a
larger quantity of water restores
its transparency. The word is
from the Persian. The tabasheer
found in the green bamboo is per-
fectly translucent, soft, and moist ;
but on exposure to the atmosphere
its moisture evaporates, and it
becomes opaque, hard, and of a
white or grey colour.

TA'BTJLAR. (from tabularis, Lat.)
Formed in lamina or plates ; hav-
ing a flat or square surface ; in
large plates.

TA'BULAR STETJ'CTTJEE. This form of
structure consists of parallel plates,
separated by regular seams ; it is
the consequence of crystallization,
and though closely allied to the
columnar structure, is not uncom-

monly confounded with stratifica-
tion.

TA'BTJLAR SPAR. (The schaalstein of
Werner ; spath en tables of Haiiy ;
prismatischer augit-spath of Mohs.)
Called also Wollastonite. A grey-
ish-white mineral, occurring mas-
sive, and in granular concretions.
Lustre pearly ; fracture splintery ;
translucent. Specific gravity 2-7
to 3-2. Its constituents are silica
51 '40, lime 45'0, oxide of iron a
trace, water 4-0. It occurs in pri-
mary rocks in Norway, and other
places.

TJENI'ADA. The second order of
Scolecida, according to Busk; it
comprises the tape- worm.

TALC. | (talk, Germ, talc, Fr.) A

TALCK. ) somewhat fibrous and very
commonly foliated mineral, resem-
bling mica in its lamellar structure,
its laminaB not being elastic as
are those of mica, but only flexi-
ble. Its colours are white, pale
yellow, or greenish. Both its sur-
face and powder are unctuous to
the touch. It is so soft as to be
easily, scratched with the finger-

. nail. Its lustre is often pearly, or
inclined to metallic. It is trans-
lucent, and, when divided into thin
laminaB, transparent. Specific gra-
vity from 2.58 to 2-90. Before
the blow-pipe it whitens, its lamina

2 i

T A L

[426]

TAP

separate, and their extremities fuse
into a white enamel. Its consti-
tuents are principally silex and
magnesia, with small quantities of
potash, alumine, oxide of iron, and
water. Talc and chlorite are nearly
allied, and pass, by insensible gra-
dations, into each other. Talc is
sometimes used as a substitute for
glass, and windows are formed of
its Iamina3, which are sometimes
obtained of the size of twelve inches
square. There are two varieties of
talc, namely, fibrous talc and in-
durated talc.

TA'LCTTE. The nacrite of Brongniart ;
talc granuleux of Hatly ; erdiger
talc of Werner. A rare min-
eral, occurring in coats or reniform
masses, composed of very minute
shining spangles or scales. "When
rubbed between the fingers, it
leaves a pearly gloss.
TALCOCA'LCTTE. A name proposed, by
Dr. Boase, to be given to a genus
of rocks. Talcocalcite is a com-
pound of granular felspar and talc :
its species all effervesce with dilute
muriatic acid. The genus is divided
into four species, namely, compact,
schistose, lamellar, and silicious :
these all possess, more or less, a
silky texture.

TALC-SCHIST. A genus of minerals in
the classification of Dr. Boase, and
thus described by him : "A basis
of granular felspar, intermixed
with, and laminated by, talc." It
is a glossy slate, having the pecu-
liar saponaceous feel of magnesian
minerals. Dr. Boase enumerates
four species : T. foliated ; T. lamel-
lar; T. crenulated; T. schistose.
Talc-schist is intimately connected
with euphotide and serpentine, by
the change of diallage into talc.
TA'LTJS. (talus, Lat. talus, Fr. incli-
nation que Von donne d la surface
laterale et exterieure d'un mur, de
telle sorte que de haut en las il aille
toujours en s1 epaississent. 11 se dit
aussi d'une terrasse sans rnurs, lors-

que ses faces laterales £ elargissent dc
Jiaut en las.}

1. A sloping heap. "When, from
disintegration, the fragments of a
face of rock accumulate at its base
and form a sloping heap, the heap
is called a talus.

2. In anatomy, a name sometimes
given to one of the bones of the
tarsus, the astragalus.

TA'NTALITE. Called also Columbite.
The ore of tantalum or columbium.
When recently broken, tantalite is
of a dark bluish-gray, or nearly
iron-black colour. It occurs in
octohedral crystals, and in small
masses. Its specific gravity is
from 5-9 to 7-9 It consists of
oxide of columbium 80, oxide of
iron 12, oxide of manganese 8.
TA'NTALTJM. A metal extracted from
tantalite; it appears to be the same
substance as columbium, and iden-
tical with it. It is one of the
simple or elementary bodies.
TA'PIK. A genus of mammalia, be-
longing to the family Pachyder-
mata Ordinaria. The nose of the
tapir may be compared to a small
fleshy proboscis, the snout being
lengthened and moveable. There
are several species of this genus
still surviving, but they are all
natives of tropical climates. The
general appearance of the tapir is
that of a pig, but some of the spe-
cies are as large as the ass. The
fore feet have four toes each, all of
equal size ; the hind feet have only
three each. The skin is of a dark
colour, nearly black, with but few
hairs.

Fossil tapirs are found in differ-
ent parts of Europe. They appear
to have far exceeded in size any of
the living species. They belonged
to the same era as the fossil ele-
phants and mastodons ; lived with
them, and were destroyed by the
same catastrophe ; their bones be-
ing found in the same strata.
TAP-BOOT. In botany, the main root

TAR

[427]

TAX

of a plant, which passes directly
downwards.

TARDIGRA'DA. | (from tardigradus,

TA'HDIGRADE. ) slow-paced, Lat.)
A family of quadrupeds of the
order Edentata. These animals
have obtained their name from the
extreme slowness of their motions.
The only existing genus is the
Bradypus or sloth. Their nails
are enormously long, compressed,
and crooked. The molars are
cylindrical ; the canini sharp, and
longer than the molars. They live
in trees, and so great is their in-
disposition to locomotion, that they
continue on the same tree till they
have devoured every leaf to be
found thereon. Some authors state
that, to avoid the trouble of a
regular descent, they tumble them-
selves down from the branch they
happen to be on. When they have
eaten their full, they can roll them-
selves into a ball, and take a long
and reckless sleep.

TAR MINERAL. A variety of bitumen,
bearing a great resemblance to
petroleum, but more viscid, and of
a darker colour.

TARN. A bog; a fen; a marsh; a
pool; a lake basin. This word
appears to be of Icelandic origin.

TA'RSAL. Pertaining to the tarsus or
instep, as the tarsal bones, &c.

TA'RSFS. (Ta/><ro$, Gr. tarse, Er.)
1. The instep, or that part of the
foot situated between the bones of
the leg and the metatarsus. In
the human subject the tarsus is
composed of seven bones, namely,
the astragalus, the os calcis, the os
naviculare, tbe os cuboides, and
three cuneiform bones. In the
lower mammalia, the number of
bones forming the tarsus, and the
general figure of this part of the
foot are very variable. In the
simiaD, as in man, the number of
the tarsal bones is seven ; in the
solidungulous anminals it is six;
in the ruminants generally five,

although in the giraffe it is four,
and in the camel six.
2. In entomology, the tarsus, or
foot, of insects is the last division
of the limb : it is divided into
several joints, which have been
supposed to represent the toes of
quadrupeds.

TAX'ODOIT. The name given by Prof.
Owen to a fossil animal discovered
in South America, in consequence
of the curvature of its teeth. He
says, " judging from the portion of
the skeleton preserved, the Taxodon,
as far as dental characters have
weight, must be referred to the
rodent order. But from that order
it deviates in the relative position
of its supernumerary incisors, in
the number and direction of the
curvature of its molars, and in
some other respects. It deviates
also, in several parts of its structure,
from the Eodentia and the existing
Pachydermata, and it manifests an
affinity to the Dinotherium and the
Cetaceous order. From the deve-
lopment of the nasal cavity and the
presence of frontal sinuses, it is
extremely improbable that the
habits of the Taxodon were so ex-
clusively aquatic as would result
from the absence of hinder extre-
mities, and Prof. Owen, therefore,
concludes that it was a quadruped
and not a cetacean; and that it
manifested an additional step in
the gradation of mammiferous forms
leading from the Rodentia, through
the Pachydermata, to the Cetacea ;
a gradation of which the water-
hog of South America (Hy drochaerus
capybara) already indicates the
commencement amongst existing
Eodentia, of which order it is in-
teresting to observe this species is
the largest, while at the same time
it is peculiar to the continent in
which the remains of the gigantic
Taxodon were discovered."

TAXO'NOMY. (from -rdgis, order, and
, law, Gr.) The classification

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or arrangement of animals or plants,
according to certain principles, in
divisions and groups.

TE'GMEN-. (tegmen, any sort of cover-
ing, Lat.) A covering of the body,
as the cuticle, &c. : used in botany
to denote one of the coats of the
seed; in entomology, applied to
the coverings of the wings of the
order Orthoptera, or straight- winged
insects.

TELEOSA'URTTS. A genus of fossil sau-
rians, thus named and arranged by
M. Geoffroy St. Hilaire. The tele-
osauri have long and narrow beaks,
the nostrils forming almost a ver-
tical section of the anterior extre-
mity of the beak. " One of the
finest specimens of fossil teleosauri
yet discovered was found in the year
1824, in the alum shale of the lias
formation at Saltwick, near Whitby ;
its entire length is about 18 feet, the
head one foot in breadth, the snout
was long and slender, as in the
gavial, the teeth one hundred and
forty in number. Some of the
ungual phalanges show that the
extremities were terminated by
long and sharp claws, adapted for
motion upon land, from which we
may infer that the animal was not
exclusively marine."

TELEO'STI. The fourth order of the
class Pisces, comprising the perch,
cod, salmon, and other ordinary
osseous fishes.

TELLI'NA. (tellina, Lat.) A genus
of orbicular, or ovate transverse,
equivalved, marine bivalves, with
a fold on the anterior part, and
short beaks, found in sands, at
depths varying to fifteen fathoms.
Hinge with usually three teeth,
the lateral ones smooth on one
side. The shells of this genus are
chiefly known by the inflection, or
irregular fold, on the fore part; in
the one valve the fold is convex,
in the other, concave. There are
three families of tellinaB : ovate and
thickish; ovate and compressed;

suborbicular. Some conchologists
have divided Tellina into three
genera ; Tellina, Cyclas, and Pan-
dora. Many species of this genus
are found fossil.

TELLI'NIDES. A genus of sub-equi-
valve, inequilateral, transverse,
marine bivalves, found in sandy
mud at depths varying from five to
fifteen fathoms.

TE'LLINITE. A fossil tellina.

TELLTJ'BIUM. The name given by
Klaproth to a metal first discovered
by him or by Miiller in 1 782, from
an ore of gold, with which metal it
is found combined in the Transyl-
vanian mines. Its colour is nearly
a tin white, with a shade of blue.
Structure foliated. Specific gra-
vity 6'1. Before the blow-pipe it
fuses easily, and is very volatile,
giving out a pungent odour, com-
pared by some to that of a radish.
Tellurium is not used in any form.
Symbols Te.

NA'TIVE TELLT/RITTM. Rhombohedral
Tellurium. The tellure natif auro-
ferrifere of Haiiy ; gediegen silvan
of Werner; tellure natif ferrifere
of Brongniart. This ore is never
perfectly pure. It always contains
a greater or less quantity of gold,
and sometimes silver, lead, copper,
and sulphur. It is found in Tran-
sylvania only, in veins, traversing
grey wacke. It is of a white colour ;
of a shining and metallic lustre;
brittle and frangible. Its constitu-
ents are tellurium 92 '6, iron 7%
gold 0-2.

TE'MPERATUEE. (temperatura)'L^t. tem-
perature, Fr. temperatura, It.) Con-
stitution of nature; the constitution
or state of the atmosphere, whether
it be hot or cold, humid or dry ;
the condition of a body, as mani-
fested by its influence on the ther-
mometer.

A question of great importance,
in the study of geology, arises as
regards the existing and the former
temperature of this planet. Whether

T EM

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TEN

the nebular hypothesis be correct, or
otherwise, it certainly does appear
that a very high temperature did
once exist on this planet; and that
such temperature has been gradu-
ally diminishing. "Whether also
the nucleus of the globe be in a state
of incandescence or fusion is a ques-
tion which probably never will be
solved, till the heavens shall be
rolled away as a curtain, and the
elements shall melt with fervent
heat. Still we well know that the
temperature of the earth does
increase in a fixed and certain
ratio as we descend into its depths.
The following are general results
from the various facts observable
on the earth's surface, and such
depths thereof as man has hitherto
been able to penetrate. 1 . Nume-
rous experiments in mines shew an
increase of temperature from the
surface downwards, that is, from
those depths where the action of
the solar rays ceases to produce a
variable heat. 2. Thermal springs
occur in all parts of the world,
and among all varieties of rock.
3. The temperature of the water
in Artesian wells is found to in-
crease with the depth. 4. Terrestial
temperature, at small depths, does
not coincide with the mean tem-
perature of the atmosphere above
it. 5. Igneous matter has been
ejected at all periods from the inte-
rior of the earth. 6. Active vol-
canoes occur widely spread over the
surface of the world, and so closely
resemble each other, that they may
be considered as produced by a
common cause, and that cause
deep-seated. 7. Geological phe-
nomena attest a great decrease of
temperature on the surface of the
globe. 8. A decreased tempera-
ture of the earth would, by radia-
tion, produce the various mountain
ranges and fractured strata found
on the surface of our planet.
When all these circumstances are

taken into consideration, and we
add the probability that heat coun-
teracts the effects of gravity in the
sun and certain planets, and that
the free passage of the particles of
terrestrial matter among each other
was necessary to produce the figure
of the earth, the evidence in favour
not only of a central heat at pre-
sent, but also of a heat of far
greater intensity at remote geolo-
gical epochs, becomes exceedingly
strong; so strong, indeed, that
there is some difiiculty in resisting
the impression that we have, by
various means, made as fair an
approximation to the truth, as the
nature of the subject will admit.
If the theory of central heat be
founded on probability, the very
general occurrence of tilted and
fractured rocks is of easy explana-
tion. From a series of experiments,
it appears that the temperature of
the earth's crust increases at the
rate of 1° Fahrenheit for every
forty-five feet of perpendicular
descent.

TE'NDKIL. (tendron, Fr.) In botany,
a spiral appendage to certain plants,
its use being to clasp and wind
round other bodies, by which means
weak and climbing stems support
themselves, and rise to a great
height.

TE'NNANTITE. A variety of sulphuret
of copper, of a lead-grey or blackish
colour, thus named by Prof. Phil-
lips. It occurs in copper veins in
some of the mines of Cornwall. Its
constituents are, according to the
analysis of Prof. Phillips, copper
45-32, arsenic 11'84, iron 9-26,
sulphur 28-74, silica 5'00. Hard-
ness 4-0. Specific gravity from
4'3 to 4-4. It occurs massive, and
crystallized in rhomboidal dodeca-
hedrons, cubes, and octohedrons.

TE'NTACLES. j Feelers ; exploring or-

TENTA'CULA. j gans. In its most
restricted sense this term is under-
stood to signify organs, appendages

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of the mouth, which have no arti-
culations; but, in a larger sense, the
term has been applied also to all
jointed organs in its vicinity, and
used for a similar purpose, which
indeed are the precursors of feelers
and antenna?. It is to these organs
that polypes are indebted for what
constitutes their principal orna-
ment, that resemblance of a plant
or shrub in full blossom, adorned
with crimson or orange-coloured
flowers. In the fixed polypes, the
tentacles are the only motive organs.
The tentacles of the fresh-water
polypes, forming the locomotive
genus hydra, are not, as those of
the fixed marine ones, shaped like
the petals of a blossom, but are
long hair-like flexible arms, some-
what resembling the branches of a
chandelier. Amongst the Radiaries,
tentacles exist in some genera, and
not in others. In the Stelleridans
and Echinidans, there are no ten-
tacles, but the Fistulidans present
a floriform coronet of tentacles.
Tentacles as exploratory, prehen-
sory, and locomotive organs, exist
in several other classes of animals.
In none, however, are they more
remarkable than in the Cephalo-
poda: in tbese animals they are
used as arms for prehension, as
legs for locomotion, as sails for
wafting their possessors over the
boundless deep, as oars for passing
through its waves, as a rudder for
directing their course, and as an an-
chor for fixing themselves. — Kirby.

TE'RBIUM. A metal having an earthy
oxide. Symbols Tb.

TEKEBE'LLA. A genus of Annelidans,
or annulose animals, placed by
Cuvier in the order Tubicola. They
are inhabitants of the sea, and are
met with generally in shallow
water, on the coasts* and on shells,
&c. The body is oblong, creeping,
naked, often enclosed in a tube,
furnished with lateral fascicles, or
tufts, and small branchias ; mouth

placed before, furnished with lips
without teeth, and protruding a
clavate proboscis; feelers numerous,
ciliate, capillary, seated round the
mouth. Terebellae not being pro-
vided by nature with any external
shell, endeavour to furnish them-
selves with an armature. For this
purpose they collect grains of sand,
or fragments of decayed shells, or
other substances, which they agglu-
tinate together by means of a viscid
exudation, so as to form a firm
defensive covering, like a coat of
mail.

TE'REBRA. A genus of turreted subu-
lated marine univalves : the open-
ing short, and notched in the lower
part. The basis of the columella
twisted : found fossil in the envi-
rons of Paris.

TE'REBRATESTG. A term applied to
shells which form holes in rocks,
wood, &c., and reside therein.

TEREBRA'TTTLA. A genus of the class
Brachiopoda. TerebratulaB are ma-
rine'Jbivalves found moored to rocks,
shells, &c., at depths varying from
ten to ninety fathoms. The valves
are unequal and united with a
a hinge, but having no ligament :
the summit of one, more salient
than the other, is perforated to
permit the passage of a fleshy
pedicle, by means of which the
animal attaches itself to rocks,
shells, &c. The recent species are
few, but the fossil are very numer-
ous, lu the fossil shell, the oper-
culum which serves for the attach-
ment of the animal to the object to
which it is moored, can rarely be
traced. The casts of some species
of fossil Terebratulae are of a most
extraordinary form. These casts
are said to have been first noticed
by Pliny, who describes certain
stones, some of which were white
and others brown. Agricola next
noticed these bodies, as having been
found whilst digging near the fort-
ress of Ehrenbreitstein, in Treves.

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After various opinions had been
offered respecting the true origin
and nature of these fossils, Woifart
advanced the opinion that they
were the casts of marine shells.
"While spiriferaB and orthoceratites
have disappeared, Terebratulse ap-
pear to have existed through all
the changes which have affected
our planet. They form, an abun-
dant genus discovered in the grau-
wacke series, not fewer than thirty
species having been already deter-
mined by Sowerby, Goldfuss, and
others, as contained therein. Among
the organic remains of the carbon-
iferous limestone, twenty-one
species of Terebratulse are enumer-
ated. From the red sandstone
group nine species have been ob-
tained. From the oolite, including
the lias, the immense number of
sixty species have been determined.
From the cretaceous group fifty-four
species have been extracted.
TEREBRA'TTJLITE. A fossil terebra-

tula.

TEBEDI'NA. (from teredo, Lat.) A
genus of acephalous testacea, be-
longing to the family Inclusa, or,
according to Lamarck, Tubicolaria.
The valves are equal and inequi-
lateral, with a little hollow on the
inside of each valve, and a small,
free, shield-shaped piece on the
hinge.

TERE'DO. (teredo, Lat. a little worm
that eateth wood; re/w^wi/, from
re/jew, to bore, Gr.) A genus of
marine bivalves, belonging to the
family Inclusa, in Cuvier's ar-
rangement, and to Tubicolaria, in
Lamarck's. The Teredo is con-
tained in the lower end of a cylin-
drical tubular shell, generally open
at both ends, two opercula being
adapted to the upper end: it is
capable of penetrating wood. One
species, Teredo gigantea, has been
found in mud at the bottom of the
ocean ; it attains to a great size,
one specimen measuring five feet

four inches in length, with a cir-
cumference, at the base, of nine
inches.

TERE'DO NAVA'LIS. The ship-worm.
The name given to a species of
Teredo from the circumstance of its
insinuating itself into the timbers
of the bottoms of ships, even
although the oak is perfectly
sound : it very soon completely
destroys the timbers it attacks.
This destructive creature was
brought originally, by our ships,
from tropical climates, but it has
now become an inhabitant of most
of the harbours of this country.
The teredo navalis, or ship-worm,
will destroy every thing constructed
of timber that is under the surface
of the water. Their object is not
to devour the wood, but to make
for themselves a cell, in which they
may be safe from their enemies.
They bore in the direction of the
grain of the timber, deviating only
to avoid the track of others. For-
tunately these animals cannot exist
in fresh water.

TE'RMINAL. (from terminalia, Lat.)
In botany, applied to flowers and
umbels proceeding from the ex-
tremity of the stem or branches.
TE'RNA FO'LIA. In botany, leaves
growing three together in a whorl.
This term, it must be remarked, is
very different in its signification
from ternate.

TE'RNABY. (ternarius, Lat.) Pro-
ceeding by threes; consisting of
three. Applied to things arranged
in order by threes : thus, in botany,
a flower is said to have a ternary
division of its parts when it has
three sepals, three petals, three
stamens, or twice or thrice as many.
TE'RNATE. (from ternus, Lat.) A
term in botany, applied to com-
pound leaves that consist of three
leaflets on a petiole : the leaf of
the strawberry affords a familiar
example of a ternate leaf.

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TERO'XIDE. } "When oxygen is cora-

TRITO'XIDE. j bined with any sub-
stance in the proportion of three
equivalents, it is called a teroxide,
or tritoxide.

TE'RRA SIE'NNA. The name given to
an ochreous earth from its being
brought from Sienna : it is a sort
of brown bole, and is used as a
pigment.

TE'RRAIIS- TERTIA'IRE. The name
given by the French geologists to
the tertiary strata. The Germans
call these, Tertiargebile.

TE'RRE VERTE. Green earth. The
grim erde of Werner ; talc zogra-
phique of Hau'y ; chlorite baldog^e
of Brongniart. An earth of a
green colour, sometimes passing to
olive. It consists, according to
Klaproth, of silex 53, magnesia 2,
potash 10, oxide of iron 28, water
6. Yauquelin states that it con-
tains 7 '00 of alumine. It is found
in Germany, France, Italy, and
North America. It is ground with
oil, and used as a pigment.

TERRE'STIAL REFRA'CTION. The power
which air possesses, in common
with all transparent media, of re-
fracting the rays of light, or
bending them out of their straight
course, rendering a knowledge
of the constitution of the atmosphere
important to the astronomer. When-
ever a ray of light passes obliquely
from a higher level to a lower one,
or vice versa, its course is not rec-
tilinear, but concave downwards ;
and of course any object seen by
means of such a ray, must appear
deviated from its true course,
whether that object be, like the
celestial bodies, entirely beyond
the atmosphere, or, like the sum-
mits of mountains, seen from the
plains, or other terrestial stations,
at different levels, seen from each
other, immersed in it. Every
difference of level, accompanied, as
it must be, with a difference of
density in the aerial strata, must

also have, corresponding to it, a
certain amount of refraction. This
refraction bet ween terrestial stations
is termed terrestial refraction. The
refraction of a terrestial object is
estimated differently from that of
a celestial body. It is measured
by the angle contained between
the tangent to the curvilineal path
of the ray where it meets the eye,
and the straight line joining the
eye and the object. The quantity
of terrestial refraction is obtained,
by measuring contemporaneously
the elevation of the top of a moun-
tain above a point in the plain at
its base, and the depression of that
point below the top of the mountain.
The distance between these two
stations is the chord of the hori-
zontal angle ; and it is easy to
prove that double the refraction is
equal to the horizontal angle, in-
creased by the difference between
the apparent elevation and the
apparent depression. Whence it
appears that in the mean state of
the atmosphere, the refraction is
about the fourteenth part of the
horizontal angle. — Mrs. Somerville.

' Sir John Herschel.

TER'TIARY. Third, a term applied to
those formations which have been
deposited subsequently to the chalk
formation.

TE'RTIARY STRA'TA. A division of
sedimentary formations called ter-
tiary, as being of newer origin
than the secondary, and character-
ized by distinct species of fossil
animals and plants. They present
a most decided contrast with the
secondary and older strata in most
of their essential characters. The
most striking feature of these for-
mations consists in the repeated
alternations of marine deposites
with those of fresh water. We
are indebted to Cuvier and Brong-
niart, for the first detailed account
of the nature and relations of a
very important portion of the ter-

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T E S

tiary strata, namely, those which
occur in the neighbourhood of
Paris. These were found to fill a
depression in the chalk, and to be
composed of different materials,
sometimes including the remains of
marine, sometimes of fresh-water
animals. The first discovery of
the tertiary strata in the Isle of
"Wight and south-east of England,
we owe to Mr. Webster. The
whole of the tertiary accumulations
are stratiform deposites, exhibiting
various kinds of lamination and
bedding. Previously to the com-
mencement of the present century,
the true nature of the tertiary for-
mations was unknown, the chalk was
considered the highest known rock,
and the tertiary deposites as mere
superficial sands, gravels, or clays.

The organic remains of the ter-
tiary deposites of England agree
with those of the Paris basin, but
the mineral character of these de-
posites is extremely different, those
rocks, in particular, which are com-
mon to the Paris basin and central
France being wanting, or extremely
rare, in England.

The tertiary system may be said
to constitute a series of formations
which link together the present
and the past ; while the more an-
cient tertiary deposites contain or-
ganic remains related to the se-
condary formations, the most re-
cent contain many existing species
of animals and plants, associated
with forms now extinct. The term
tertiary has been altogether dis-
approved of by some geological
authors.

The tertiary strata have been
sub-divided by Sir C. Lyell and M.
Deshayes into four principal groups,
to which Sir C. Lyell has assigned
the terms eocene, miocene, pliocene,
and pleistocene ; each group being
characterized by the relative pro-
portion of recent and extinct spe-
cies of shells therein contained.

Commencing from below up wards,
we find included in the tertiary
series. 1. The eocene, comprising
marine and fresh-water deposits,
including in the former, the cal-
caire grossier and the London clay ;
in the latter, the calcaire silicieux.
2. The miocene, comprising the fa-
luns of the Loire, marine deposits,
and sands, clays, lignites, &c., &c. ;
fresh- water deposits. 3. The plio-
cene, consisting of sub-apennine
marl, sub-apennine yellow sand*
English crag, marine deposits ; and
sands, clays, lignites, &c., fresh-
water formations. 4. Pleistocene,
in this, the most recent of the ter-
tiary deposits, we have limestone,
sand, clays, conglomerates, marls,
&c., containing marine fossils, be-
ing marine stratifications; and
sands, clays, sandstones, lignites,
&c., containing fresh-water fossils,
being fresh- water deposits.

TE'SSELATED. (tesselatus, Lat. wrought
in chequer- work.) Chequered, like
a chess board. In conchology, ap-
plied to shells that are coloured iu
regular and defined patches.

TE'SSULAK. A term applied to a sys-
tem of crystallization, not suscep-
tible of variation. The cube, te-
trahedron, and several other forms
belong to the tessular system.

TE'STA. (testa, Lat. a shell.)

1. Commonly applied to the shelly
covering of testaceous animals.

2. In botany, the outer coat of the
seed. The seed, or ripened ovulum,
consists of coverings called integu-
ments or seed- coats, the outer of
which is called the testa.

TESTA'CEA. (from testa, Lat. a shell.)
In the Linnaen system of natural
history, the third order of Vermes.
This order comprises all shell-fish,
arranged by Linnaeus under thirty-
six genera. The testacea differ
from the Crustacea in their compo-
sition; the calcareous part of the
shells of testacea being carbonate
of lime, whereas in the shells of

2 K

T E S

[434]

THE

Crustacea it is phosphate of lime.
The testacea also retain their shells
as long as they live ; the Crustacea
cast them annually, or, at least,
periodically.

TESTA'CEOUS. (testaceus, Lat. testacee,
Er. testaceo, It.) Belonging to the
the order Testacea ; having a strong
thick shell, the calcareous portion
of which consists of carbonate of
lime.

TESTU'DINATE. (testudinatus, Lat.)
Arched ; vaulted j resembling the
back of a tortoise.

TESTU'DO. (testudo, Lat.)

1. A genus of the order Chelonia;
the tortoise. This genus has been
divided into five subgenera.

2. The land tortoise, a sub-genus
of the genus above mentioned.

TE'TRABRANCHIA'TA. The second order
of the class Cephalaphora, compri-
sing the nautilus, ammonite, &c.

TETRACAU'LODOF. An extinct animal
of the order Mammalia ; allied to
the mastodon, and referrible to the
miocene period.

TETRADA'CTYLOUS. (from TerpaSdicTv-
Xo?, Gr.) Having four toes.

TETRADYNA'MIAIT. | A term applied to

TETRADYNA'MOTJS. j plants that have
six stamens, four of which are
longer than the other two: the
wall -flower is a familiar example.

TE'TRAGYN. In botany, a plant that
has four pistils.

TETRAHE'DRAL. Having four triangles,
equal and equilateral.

TETRAHE'DRON. | (from rerpa, four,

TETRAC'DRON. j and etya, side, or
base, Gr. Utraedre, Er.) The solid
angles of a tetrahedron are formed
by three equilateral plane triangles,
and the solid is bounded by four
equal and equilateral plane tri-
angles, therefore it is a pyramid ; a
four-sided solid contained by four
equal- sided triangles ; a solid con-
tained by four triangular surfaces.

TnAi/icTRUM. } The name

THALICTRO'IDES WEBSTERI. j given to
a fossil plant resembling the mea-

dow-rue, and found in the London
clay.

THA'LLITE. The name given by Leme-
therie to the Epidote of Hau'y, or
Pistazit of Werner.

THA'LLUS. (from 0a\\os, a green
leaf, Gr.) In botany, a name given
to the frond, or leaf-like part, of
certain plants. Lichens, are stem-
less, leafless plants, consisting of a
tough wrinkled substance, called a
thallus,

THA'LOGEN. The thalogens constitute
a class of plants comprising four
orders; algas, fungi, lichens, and
characese.

THE'CA. (from Ofay, Gr. theca, Lat.)
A case or sheath. The sporules of
plants are contained within thecae.

THECODONTOSAU'RTJS. A genus of fos-
sil saurians, found in the magnesian
limestone : the vertebrae are deeply
concave at each end.

THELO'DUS. (from #17X1), mamilla,
and o£ovs, dens, Gr. mammillated
tooth.) A genus of ichthyolites
discovered in the Upper Ludlow
rock, and thus named by Agassiz.
The teeth of the Thelodus resemble
in some respects those of the Lepi-
dotus. One species only is descri-
bed, namely, Thelodus parvidens.

THE'RMAL. (thermal, Fr. Oep/ib<t,
warm, Gr.) A term applied prin-
cipally to warm springs and waters.
The temperatures of different ther-
mal springs vary greatly from each
other, but the same spring is found
to be of a uniform temperature at
all seasons of the year. Thermal
waters are found to be, on the aver-
age, neither more nor less pure
than springs of common tempera-
ture. It appears, from Dr. Dau-
beny's researches, that nitrogen
gas is very common in hot springs,
and, perhaps, very rare in cold
waters. Thermal waters prove the
extensive effects of subterranean
heat, deriving their temperature
from a deep-seated internal source
of heat, and not from any local

THE

I 435 ]

TIB

cause, or from chemical changes.
Some thermal springs have flowed
without any known diminution of
temperature for nearly two thou-
sand years. The evidence that
many springs rise from considerable
depths, and possess a temperature
independent of solar influence, rests
on their great heat, which varies
from the boiling point of water
downwards, to ordinary tempera-
tures. It is impossible to account
for this, otherwise than by suppo-
sing such heat communicated to
the water in parts of the earth far
beneath the surface, and removed
from atmospheric influence. Many
thermal springs contain silica,
though this substance is of exceed-
ingly difficult solution. Dr. Tur-
ner found that some of the thermal
springs of India which yielded
twenty-four grains of solid matter
in a gallon, contained 21 -5 percent,
of silica, 19 of chloride of sodium,
19 of sulphate of soda, 19 of carbo-
nate of soda, 5 of pure soda, and
15*5 of water. Dr. Back gives the
following as an analysis of the
thermal waters of the geysers of
Iceland : soda 5*56, alumina 2*80,
silica 31*50, muriate of soda 14*42,
and sulphate of soda 8 '57.

THEK'MOSCOPE. (from 0e/ytos, heat,
and aicoTreui, to explore, Gr.) An
instrument for measuring the
degrees of heat.

THIN OUT. This is a term used by
geological writers to express the
appearance of a stratum which
gradually becomes thinner, till it
wholly disappears.

THO'MSONITE. A mineral, thus named
after Dr. Thomson, a variety of
zeolite, crystallized in rectangular
prisms. It is found near Dumbar-
ton, in Scotland, in trap.

THORA'CIC. (thorachtque, Fr. from
thorax, Lat.) Pertaining to the
chest. The name given to the duct
into which the absorbents empty
themselves, namely, the thoracic

duct, and which terminates in the
left subclavian vein.

THO'RAX. (thorax, Lat. Oupa%, Gr.
thorax, Fr.) The cavity of the
chest, containing the heart, lungs,
&c., &c.

THORI'NA. An earth discovered by
Berzelius, in Gadolinite. It bears
a strong resemblance to zirconia,
but differs from it in many particu-
lars. After being heated to redness
it is soluble in acids. No precipi-
tate is caused by the addition of
sulphate of potash to a solution of
it. Thorina is colourless, and infu-
sible after ignition. Dr. Ure states
that a strong solution of the sul-
phate becomes a thick mass by
boiling, but it is soluble in cold
water; a property which particu-
larly characterizes it.

THORI'NUM. \ The metallic base of the

THORI'UM. j earth thorina.

THO'RITE. A mineral discovered in
Norway, by Esmark, and named
thorite by Berzelius. It is com-
pact; of a black colour; brittle.
Specific gravity 4-8. It is rare,
and not used.

THU'LITE. A mineral of a peach-
blossom colour, occurring in Nor-
way ; it is very rare, and considered
to be a variety of epidote.

THTJ'MERSTQNE. j A mineral, thus

THT/MMERSTONE. j named, by Kir-
wan, from its being found, in
masses, near Thum, in Saxony.
It is the Axinite of Hau'y and
Brongniart ; the Axinit of Werner ;
La pierre de Thum of Brochant.
See Axinite.

THYRSE. } (thyrsus, Lat) In botany,

THY'RSUS. j a kind of inflorescence,
as when the middle branches of a
panicle are longer than the others.
The horse-chesnut, lilac, &c., afford

TI'BIA. The name given to the shin-
bone, or large bone of the leg. It
is said to have received its name
from a supposed resemblance to a
pipe or flute.

T I D

[436]

TIL

TIDE, (eble and fluth, Germ, flusso
del mare, It.) The flow of the
water in the ocean ; the alternate
rise and fall of the sea twice in the
course of a lunar day, or in 24h.
50m. 28s. of solar time. The
tides are a subject on which many
persons find a great difficulty of
conception. As the tides depend
upon the action of the sun and
moon, their rise and fall are classed
among astronomical problems, of
which they are the most difficult,
and their explanation the least
satisfactory. That the moon, by
her attraction, should heap up the
waters of the ocean under her,
seems to most persons very natural,
— that the same cause should, at
the same time, heap them up at
the opposite, appears to many a
palpable absurdity. Yet nothing
is more true, nor indeed more evi-
dent, when we consider that it is
not by her whole attraction, but by
the differences of her attractions, at
the two surfaces and at the centre,
that the waters are raised. In the
semi-diurnal tides there are two
phenomena particularly to be dis-
tinguished, one occurring twice in
a month, and the other twice in a
year. The first phenomenon is
that the tides are much increased
in the syzigies, or at the time of
new and full moon. In both cases
the sun and moon are in the same
meridian: for when the moon is
new they are in conjunction ; when
she is full they are in opposition.
In each of these positions, their
action is combined to produce the
highest or spring-tides under that
meridian. The neap-tides take
place when the moon is in quadra-
ture. The higher the sea rises in
full tide, the lower it is in the ebb.
The second phenomenon is the aug-
mentation in the tides occurring at
the time of the equinoxes, when
the sun's decimation is zero, which
happens twice every year. The

greatest tides take place when a
new or full moon happens near the
equinoxes, while the moon is in
perigee. The height to which the
tides rise is much greater in narrow
channels than in the open sea, on
account of the obstructions they
meet with. The tides in the Brit-
ish channel sometimes, in some
parts, rise as high as fifty feet;
whereas on the shores of some of
the islands near the centre of the
Pacific ocean, they do not exceed
one or two feet. Theoretically,
all bodies of water, even large
fresh water lakes, have tides ; but
they are so insignificant that in-
land seas, such as the Mediter-
ranean and Black Seas, are gene-
rally termed tideless. One of the
most remarkable circumstances in
the theory of the tides is the as-
surance, that in consequence of the
density of the sea being only one-
fifth of the mean density of the
earth, and the earth itself increasing
in density towards its centre, the
stability of the equilibrium of the
ocean can never be subverted by
any physical cause. A general
inundation arising from the mere
instability of the ocean is therefore
impossible. — HerscMl.
TIL'ESTONE. The name given to that
formation which constitutes the
third or lowest division of Sir
R. Murchison's Old Red system.
The tilestone, though of much
smaller dimensions than the over-
lying formations, has very marked
characters both in structure and
fossil contents, and is very clearly
defined by occupying a position in
which it "passes upwards into the
cornstone and marls, and down-
wards into the Silurian rocks.
The beds are finely laminated,
hard, reddish or green, micaceous,
quartzose sandstones, which split
into tiles. Although the greenish
colours prevail, these beds are
usually associated with reddish

TIL

[437]

TIN

shale, and the decomposition of the
mass uniformly produces a red soil,
by which character alone the out-
line of the division is easily defined ;
being always clearly separable from
the upper beds of the Silurian
system, which decompose into a
grey surface. Organic remains are
abundant, and indicate clearly the
lines of deposit. The fossils consist
of unpublished species of the fol-
lowing genera : Area, Avicula,
Bellerophon, Cucullcea, Lingula,
Orthoceras, Terebratula, Turbo,
Turritella, Trochus. This assem-
blage furnishes convincing proof
that certain genera of molluscs,
which have hitherto been supposed
to be confined to the tertiary and
secondary deposits, have co- existed
with the genera Orthoceras, Tere-
bratula, and Bellerophon, which
peculiarly characterize the older
strata.

The fact may now be regarded
as established, that the Tilestones
of England belong to a deposit
contemporaneous with the ichthy-
olite beds of Caithness and Cro-
marty. — Hugh Miller.

The tilestones of England com-
pose the least of the three divisions
of the Old Red Sandstone system ;
their representative in Scotland
forms by much the greatest of the
three, and there seems to be zoo-
logical as well as lithological
evidence that its formation must
have occupied no brief period.
The same genera occur in its upper
as in its lower bed, but the species
appear to be different. — Hugh
Miller.

TIL'GATE BEDS, OR STRATA OF TILGATE
FOREST. These form the central mem-
bers of the Hastings beds, one of
the three divisions of the "VVealden
• formation. The Tilgate strata or
beds consist of sand and friable
sandstone, of various colours ; of a
compact bluish or greenish grey
grit, in lenticular masses, its

surface often covered with mamil-
lary concretions, the lower beds
frequently conglomeritic, and con-
taining large quartz pebbles ; and
clay or marl, of a bluish grey
colour, alternating with sand,
sandstone, and shale. Its organic
remains consist of bones and shells,
rarely occurring, ferns and stems
of vegetables. The Tilgate beds
are met with in Sussex and Kent.
TIN. (zinn. Germ.) A metal of a
white brilliant colour, slightly
tinged with grey, being one of the
simple or elementary bodies. Its
specific gravity is 7'0 to 7'9. It
fuses at a temperature of 442°
Fahrenheit. It is of greater hard-
ness than lead, but not so hard as
gold. It is very malleable, and
may be beaten out into leaves
one two- thousandth of an inch in
thickness. It is more tenacious
than lead, and a wire of tin one-
tenth of an inch diameter will
sustain a weight of forty-seven
pounds. It is very flexible, and,
while being bent, it causes a crack-
ling noise. Tin unites with many
metals, forming valuable alloys.
Its symbol Sn, from its Latin name
Stannum. The bronze of the
ancients consisted of 88 or 90 parts
of copper, with 10 or 12 parts of
tin. Bell metal consists generally
of one-fifth of tin to four- fifths of
copper. The gongs of the Chinese
are formed of one-fifth of tin and
four-fifths of copper.

Tin is mentioned repeatedly in
the Pentateuch. It is generally
believed that the Phoenicians came
to Britain for tin, and, from the
importance of the trade, that they
concealed the situation whence it
was obtained; it is certain that
before the time of Herodotus tin
was obtained from Cornwall. The
period at which Cornish tin was
first worked and exported would
appear to be lost in the obscurity
of past ages. Mr. Hawkins con-

TIN

[ 438 ]

TOR

siders that the Phoenician colony
of Gades, on the western coast of
Spain, was the medium or entrepot
of the commercial intercourse be-
tween Phoenicia and Cornwall.
Diodorus says, " we will now give
an account of the tin which is
produced in Britain."

Tin occurs in rocks of granite,
gneiss, &c., in veins or fissures,
called lodes ; also in horizontal
beds termed floors ; and it is also
found loosely scattered among
pebbles.

TINSTONE. Oxide of tin; an ore
containing tin. Tinstone sometimes
yields nearly 80 per cent, of its
weight in tin.

TI'TANITE. The ore or oxide of ti-
tanium ; it is nearly a pure oxide,
is of a brown colour, and is met
with in granite and quartz.

TITANIUM, (from T/TOI/OS, Gr.) One
of the substances commonly known
as metals. Titanium was first
discovered by the Rev. Mr. Gregor
in 1789 ; it is of a dark, copper-
red colour, with a strong metallic
lustre, which tarnishes by exposure
to the atmosphere. Werner gaVe
the name of Menak to titanium,
from the circumstance of its having
been first found at Menachan, in
Cornwall.

TOAD-STONE. A provincial term for
a species of wack, or basaltick rock,
found in Derbyshire. Toad-stone
is a pyrogenous or volcanic pro-
duction that has been erupted in a
fluid state. Its ordinary colours
are brownish grey, purplish brown,
bluish, or greenish; and its vesicles
are either empty, or filled with
carbonate of lime. Toadstone is
found abundantly in Derbyshire,
lying between beds of limestone ;
in some instances, beds of toadstone
and limestone are found alternating
with each other.

TONGUE- SHAPED. In botany, applied
to leaves of an oblong, blunt, thick
form, being generally of a cartila-

ginous substance at the edges.

TO'PAZ. (from TOTTCL^IOV, Gr. topaz,
Fr.) A precious stone or gem,
generally of a yellow colour. It
is the silice fluatee alumineuse
of Haiiy ; the topaze of Brongniart
and Brochant. It is harder than
quartz, hardness = 8, with a
specific gravity of from 3*4 to 3'6.
Is massive, in rounded pieces, and
crystallised ; most frequently crys-
tallised. According to Haiiy the
primitive form of topaz is a rec-
tangular octahedron. Mr. Allan
says " its structure is lamellar at
right angles to the axis of the
prism ; it also cleaves, though
with difficulty, parallel to the
sides of a right rhombic prism of
about 124° 22' and 55° 38'; and
it appears to yield to mechanical
division on all the angles of the
prism. There are many varieties
of topaz, differing greatly in form
and colour. The highly crystal-
lised and transparent varieties are
named precious topaz. In some
places, as in Scotland, the topaz is
found in alluvial earths. The
Scotch pebble, called cairn-gorum,
is a topaz. Generally, the topaz
occurs in primary rocks, the finest
specimens being obtained from the
mountains of Brazil, and from the
Uralian mountains of Asiatic Russia.
Other minerals are sometimes sold
for topaz, but it may generally
be distinguished by the rhombo-
hedron base of its crystals, straight
foliated cross fracture, and longitu-
dinally streaked lateral planes. The
precious topaz consists of alumina,
silica, and fluoric acid, with, some-
times, a small quantity of iron.

TOPA'ZOLITE. A pale yellow, nearly
transparent, sub-variety of garnet,
found in Piedmont. Its constitu-
ents are, silex 37, alumine 2, linffc
29, glucine 4, iron 25, manganese
2.

TOR. A small round hill; called
also Cam, or Kara.

TOR

[439 ]

TEA

TOENATE'LLA. A genus of oval, spi-
rally grooved, marine, univalves,
belonging to the family Plicacea.
Eecent tornatellffi are found in
shallow water, creeping on sands,
and leaving furrows. Several spe-
cies are found in the oolite and
super] acent strata.

TOEO'SE. | (torosus, Lat.) Swelling

TO'EOUS. j into knobs or protuber-
ances. A term used both in botany
and conchology.

TOBPE'DO. (torpedo, Lat. from torpeo,
to benumb.) A subgerms of ashes,
belonging to the genus Raia. The
torpedo is found fossil in the ter-
tiary formations. The torpedo is
furnished with an electrical appa-
ratus, resembling the voltaic bat-
tery, which it has the power of
charging and discharging at plea-
sure. The benumbing effect pro-
ducible by the torpedo depends on
certain singularly constructed or-
gans composed of membranous
columns, filled from end to end
with laminae, separated from each
other by a fluid.

TO'ERELITE. A new mineral brought
from the United States, and thus
named after Dr. Torrey.

TO'ETOISE. (tortue. Pr.) An order
of the class Reptilia, or reptiles ;
tortoises are also termed Cbelonians.
The chelonians, or tortoises, were
all included by Linnaaus in one
genus, namely, testudo ; they are
now divided into five subgenera.
1. Testudo, or land- tortoise ; 2.
Emys, or fresh- water tortoise; 3
Chelonia, or sea- tortoise ; 4. Che-
lys; 5. Trionyx, or the tortoise
with a soft shell.

The Testudo Indicus, a species
of land tortoise, sometimes attains
to an immense size, so as to require
six or eight men to lift it from the
ground, and affording as much as
two hundred pounds of meat.

This order of reptiles, geologists
inform us, began to exist at about
the same period with the order of

Saurians, and has continued from
that time to the present. No fossil
remains of the tortoise have been
discovered in any strata not more
recent than the coal formations.

TO'EALOSE. In entomology, a surface
with but few elevations, scattered
about, but these of considerable
size.

TOU'EMALINE. } A mineral divided by

TOT^EMALIN. j some mineralogists
into two sub-species, schorl and
tourmaline ; by others, tourmaline
is regarded as a sub-species, or va-
riety of schorl. The tourmalin of
"Werner ; the tourmaline verte of
Hany ; the schorl electrique of
Brochant. — It is of various colours,
the shades of some of which are so
dark as to approach nearly to black :
hardness about 7*5. Sp. gr. from
3-0 to 3-2. By friction it yields
vitreous electricity ; by heating,
vitreous electricity at one extrem-
ity and resinous electricity at the
other, the termination, according
to Haiiy, which presents the
greatest number of planes, exhibit-
ing the positive, or vitreous, elec-
tricity, the termination which con-
sists of the smaller number of
planes exhibiting the negative, or
resinous, electricity. It occurs but
seldom massive, most frequently
crystallized; its primary form is
an obtuse rhomboid of 133° 50',
and 46° 10'. It occurs imbedded
in granite, gneiss, mica slate, &c.,
in Scotland, Sweden, America,
Spain, and other parts.

TBA'CHEA. (trachea, Lat. from rpa^v^
Gr. rough.)

1. The windpipe, or that canal
which leads from the throat to the
lungs.

2. In botany, the vessels of plants
in which the internal fibres run in
a spiral direction; they are also
called air-tubes.

TEACHEA'ETA. The third order of the
class Arachnida : the acarus is an
example.

TEA

[ 440

TEA

TRACHE'LIPODS. (from r/ja^Xov, the
neck, and TTOVS, a foot, Gr.) In
Lamarck's arrangement, the third
order of Molluscans : they have the
greatest part of the body spirally
convolved, always inhabiting a
spirivalve shell ; the foot free, at-
tached to the neck, formed for
creeping. Trachelipods may be
divided into herbivorous and car-
nivorous, the latter possessing a
respiratory siphon, which the her-
bivorous have not. This order
contains fourteen families, and up-
wards of seventy genera.

TBA'CHYTE. (from rpaxvs, Gr. rough.)
A kind of volcanic porphyry, usu-
ally containing crystals of glassy
felspar, and excessively rough to
the touch. It is found in the
neighbourhood of all volcanic cra-
ters. Trachyte sometimes possesses
a columnar structure ; it is gener-
ally of a coarse grain, and with a
degree of porosity. From this
latter circumstance it easily breaks
down, and forms frequently a con-
glomerate with other substances.
It sometimes is found to contain
augite and hornblende. In some
districts trachyte seems little else
than granite which has been again
fused, and, having been exposed to
different conditions, no longer pre-
sents the appearance of granite.
Mr. Poulett Scrope proposes to
divide trachyte as follows: — 1.
Compound trachyte, with mica,
hornblende, or augite, sometimes
both, and grains of titaniferous
iron. 2. Simple trachyte, without
any visible ingredients but felspar.
3. Quartziferous trachyte, when
containing numerous crystals of
quartz. 4. Silicious trachyte, when
apparently much silex enters into
its composition.

TRACHYDO'LERITE. A sort of inter-
mediate lava. The name trachy-
dolerite is proposed by Abich to be
given to certain lavas where the
minerals pass into one another, or

are so intimately blended that they
cannot be distinguished.
TRANSITION ROCKS. \ The name

TRANSITION SERIES. > transition

TRANSITION TORMA'TIONS. ) given by
Werner, has been applied to certain
rocks, from an opinion that they
had been formed at a period when
the globe was undergoing a great
change, fitting it for the reception
of organized beings : or it was
adopted to express the theory that,
at this period, the causes which
had given rise to crystalline forma-
tions were still in action ; while
those which produced stratified
sedimentary rocks, including or-
ganic remains, were only beginning
to operate. The term, though no
longer applicable in its original
signification, is still retained. The
rocks usually included in the tran-
sition* series are the Dudley lime-
stone, the Caradoc sandstones, and
the British and Llandilo rocks ; the
whole possessing a thickness of up-
wards of two thousand four hundred
yards, and containing, throughout,
organic remains. The transition
rocks rest upon the rocks called
primary, and are themselves cov-
ered by the old red sandstone for-
mation. Buckland observes, "it
is most convenient to include
within the transition series, all
kinds of stratified rocks, from
the earliest slates, in which we
find the first traces of animal or
vegetable remains, to the termi-
nation of the great coal formation.
Upwards of six hundred species of
fossils have been discovered in the
transition rocks. They are mostly
peculiar to these rocks, though
some occur also in the carbonifer-
ous system, and are nearly all
marine. About 66 per cent, belong
to genera supposed to be extinct.
The mineral character of the tran-
sition formations present alterna-
tions of slate and shale, with slaty
sandstone, limestone, and conglo-

TEA

[441 ]

TEA

merated rocks ; the latter bearing
evidence of the action of water in
violent motion ; the former show-
ing, by their composition and
structure, and by the organic re-
mains which they frequently con-
tain, that they were for the most
part deposited in the form of mud
and sand, at the bottom of the sea."

TRANSI'TION LIME' STONE, (calcaire de
transition, calcaire intermediare, Pr.
ueleryangskalkstein, Germ.) A
member of the Grauwacke group,
called also Grauwacke Limestone.

TBANSLT/CENCY. (from trans, through,
and luceo, to shine, Lat.) A term
used in mineralogy, to express the
property which, some minerals pos-
sess, of permitting the passage of
rays of light, but without sufficient
transparency to perceive objects
through the mineral.

TRANSLUCENT. A mineral is said to
be translucent when light evidently
passes, but objects cannot be dis-
tinguished through the mineral.

TRAP. | (trappa, a stair, Sw.

TRAP ROCKS. } trapp, a step, Germ,
probably from -rpaire^a, Gr. a table.)
Bergman gave the name of trap to
basalt, which he divided into two
families, namely, Common Trap,
and Pigurate Trap. The word
trap is usually employed to desig-
nate certain volcanic rocks, fre-
quently occurring in large tabular
masses at different heights, forming
a succession of terraces or steps.
The term is applied to various
igneous rocks without any regard
to their constituent parts, but
merely in reference to their form.
Great alterations are produced on
stratified rocks by the introduction
of trap rocks ; these consist in some
cases in the greater degree of in-
duration, by which loose grits pass
into compact quartz rock, and shale
into flinty slate ; coal is converted
into coke, or becomes charred,
forming an ash-grey porous mass,
which breaks into small columnar

concretions, exactly resembling the
coak obtained by baking coal in
close iron cylinders. Limestone is
often rendered highly crystalline
and unfit for lime, when in the
vicinity of trap-rock; and slate
clay is turned into a substance
resembling flinty slate or porcelain
jasper. Many of the trap-rocks,
like some lavas, afford on decompo-
sition one of the most fertile soils
with which we are acquainted. A
slight acquaintance, says Sir E.
Murchison, in his splendid work,
" The Silurian System," with vol-
canic phenomena teaches us that
they are the results of some general
and deep-seated cause, which occa-
sions eruptions of gaseous and
earthy matters, or of lava, both
under the atmosphere and beneath
the ocean. It is perhaps to sub-
marine volcanoes that all our Brit-
ish trap-rocks are referable. The
most common ingredient in trap as
well as in granitic rocks, is felspar.
TRAPE'ZIUM. (from rpairegiov, a little
table, Gr.)

1. In anatomy, the name given to
one of the bones of the carpus, or
wrist.

2. In geometry, a quadrilateral
figure, whose four sides are not
equal, and none of its sides parallel.

TRAPEZOI'DAL. In mineralogy, when
the surface is composed of twenty-
four trapeziums, all equal and
similar.

TRASS. The name given to a tufa-
ceous alluvium of the Ehine vol-
canoes. Lyell says, * ' this trass is
unstratified; and its base consists
almost entirely of pumice, in which
are included fragments of basalt
and other lavas, pieces of burnt
shale, slate, and sandstone, and
numerous trunks and branches of
trees."

TRAU'MATE. The name given by the
French geologists to grauwacke, a
term about as euphonious as that
they have substituted it for.

2 L

T E A

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TEE

TBA'VEETIN. (Lapis Tilurtinm, Lat.
travertino, It.) An Italian name
for a concretionary limestone or
calcareous precipitate, deposited by
water holding in solution a consid-
erable quantity of carbonate of lime.
The water parting with some of its
carbonic acid gas, which rises in
bubbles to the surface, the lime be-
comes deposited. Thermal springs,
in volcanic districts, are found to
issue from the earth, so highly
charged with carbonate of lime, as
to overspread large tracts of country
with beds of calcareous tufa, or
travertin. Deposits of travertin
are by no means uncommon from
cold springs in the Apennines, par-
ticularly near the volcanic region
of Southern Italy. In Italy, im-
mense masses of travertin are being
constantly formed from waters
copiously charged with carbonate
of lime. At the baths of San
Fillippo a manufactory of medal-
lions in lasso-relievo is carried on.
The water is first conducted into
pits, where it frees itself from its
grosser parts ; it is then conducted
by a tube to the top of a small
chamber, and made to fall through
a space of ten or twelve feet in
height. The stream is broken in
its descent by means of numerous
sticks placed across, by which the
spray is dispersed upon moulds,
which are slightly soaped, and the
result is a cast of the figures formed
in the mould, of a solid, marble-
like substance. The waters of the
lake of the Solfatara, between Eome
and Tivoli, are so supersaturated
with carbonic acid gas, that they
appear in a constant state of ebul-
lition, from the extrication of the
gas. The Coliseum, and the ma-
jority of the public buildings of
Home, are composed of travertin.
The usual explanation of the depo-
sition of travertin seems very pro-
bable. It supposes the carbonic
acid to be derived from the volcanic

regions beneath, which, passing
with the water through the calca-
reous strata, dissolves as much lime
as it can take up, giving off the
excess of carbonic acid under di-
minished pressure in the atmos-
phere, and causing the carbonate
of lime to be deposited. The car-
bonic acid found so abundantly in
acidulous springs is ascribed by
Von Buch, Brongniart, Boue, Von
Hoff, and other geologists, to vol-
canic or igneous action at various
depths beneath the surface. Masses
of travertin are very abundant in
districts which have been, or still
are, subjected to volcanic action;
they are, however, almost equally
abundant in countries where there
are no distinct appearances of vol-
canic action near the surface. All
that seems necessary for their pro-
duction is, that a spring, should
hold in solution a sufficient quan-
tity of carbonate of lime, which,
upon the escape of the excess of
carbonic acid gas into the atmos-
phere, deposits its earthy residuum
on any object over which it flows.
TBE'MOLITE. (from Tremola, a valley
of St. Gothard, where it was first
found.) A nearly white, grey, or
bluish, variety of hornblende or
hemiprismatic augite. It occurs
in crystals, but most commonly in
fibrous or radiated masses, composed
of minute, imperfect prisms or fibres.
There are several sub-varieties of
tremolite, namely, common tremo-
lite, glassy tremolite, fibrous tremo-
lite, and Baikalite. Tremolite is
found almost exclusively in primary
rocks, but it sometimes occurs in
secondary. Specific gravity from
2-9 to 3-2. Hardness from 5'0 to
6-0. Before the blow-pipe, tremo-
lite fuses into a white glass, full of
pores. Its consituents are silex,
lime, magnesia, water and carbonic
acid, and oxide of iron. Very dif-
fering analyses are, however, given
by different chemists and mineralo-

T R I

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T R I

gists ; some describe it as contain-
ing fluoric acid and alumina.
TEIA'NDEIA. (from rpci?, three, and
avrjp, a male, Gr.) The name of
the third class in Linnasus's sexual
system, consisting of plants with
hermaphrodite flowers, having three
stamens or male organs. This class
is divided into three orders: — 1.
Monogynia. 2. Digynia. 3. Tri-
gynia.

TEIAS, OE NEW RED SANDSTONE. (Some-
times called l Poikilitic? from the
prevalence of a variegated character
in its sandstones, and marls.) On
the continent where its several
members are better developed than
in England it has received the name
of 'Trias,' as divisible into three
great sub-divisions. The lowest
sub-division is the Bunter sand-
stone ; the second, or Muschelkalk,
is deficient in England ; the upper
is the Keuper marls, which contain
our great deposits of salt. Upon
the northern and southern flanks
of the Austrian Alps, at Hallstatt
and St. Cassian, are deposits of great
thickness, which are superimposed
upon the upper members of the
Trias, and are regarded as forming
a passage between the Trias and
the Lias ; the bone beds upon the
banks of the Severn at Westbury
and Aust are believed to be the
reduced equivalents of these great
deposits. — Lycett.

TEIA'SSIC. " This," says Mr. Jukes,
"is a very badly chosen name. The
triassic formation consists of the
Bunter sandstein, the Muschelkalk,
and the Keuper. In the British
Islands it is not easy to draw any
boundary lines in the Trias, or New
Red Sandstone."

TEICA'PSULAB. A plant that has three
capsules to each flower.

TEICHI'TES. The name assigned by
Mr. Lycett to a genus of fossil
inequivalve bivalves, whose struc-
ture is fibrous, the substance of the
test being of great thickness. The

hinge is without teeth or hinge-
plate, and the anterior extremity
of the shell, which is pointed, forms
an aperture ; the general figure is
sub-quadrate, the valves being ir-
regular and undulated, but closing
all round. This singular genus
occurs in the oolitic system of rocks :
the absence of teeth, and the char-
acter of the terminal extremity
distinguish it from Catillus.

TEICU'SPIDATE. Three-pointed.

TEIDA'CNA. A genus of subtransverse
inequilateral, equi valve, marine,
bivalves, belonging to Lamarck's
family of Tridacnacea, and found
both recent and fossil. Recent
tridacna3 are found at depths vary-
ing to seven fathoms, moored by a
byssus to rocks, and on coral reefs.
The shells of this genus are ex-
ceedingly beautiful, being radiately
ribbed, the ribs adorned with vaulted
foliations, and waved at the margins.
The hinge is formed of two com-
pressed and entering teeth. One
species, the tridacna gigas, is met
with of immense size. Fossil shells
of this genus are very rare ; it is
said some large specimens have
been obtained from the neighbour-
hood of Yerona.

TEIDA'CTYLOTJS. Having three toes.

TEIGONELLI'TES. A genus of shells
described, and thus named, by Mr.
Parkinson. A slightly rounded,
trigonal, thick shell, gaping on
each side. The anterior margin
nearly on a straight line ; the pos-
terior in a gently waving, and the
upper side in nearly a circular
direction. The outer surface of
each valve thickly pierced by
foramina, which, passing nearly
through its substance, give it the
cancellous appearance of bone : the
inner surface smooth, but marked
with striaB, concentric with the
upper margin. Tlte hinge com-
pletely linear, without teeth ; there
being only an appropriate surface
on the anterior margin of each

T E I

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T E I

valve for the attachment of the
cartilage externally.
TRIGO'NIA. \ (from Tpi^wvov, triangu-
TRI'GON. lar, Gr.) A genus of

TEY'GON. ) marine bivalves, found
both fossil and living, belonging to
the family Ostracea. The trigonia
is a triangular or suborbicular, in-
equilateral, equivalve, transverse
bivalve. One valve has two oblong,
flat, diverging, hinge teeth, trans-
versely grooved on each side ; the
other "has four flat, oblong, di-
verging, hinge teeth, transversely
grooved on one side only, disposed
in pairs, receiving between their
grooved sides the two hinge teeth
of the opposite valve. Eecent
trigoniae have hitherto been dis-
covered near Australia only, in
sandy mud. They are nearly
related to the cardium, or cockle,
the foot of the animal being bent,
like that of the cockle, at an acute
angle, so as, upon pressure, to form
a very elastic organ.
TRILO'BATE. (from ires, three, and
lobus, a lobe, Lat.) Divided into
three lobes ; having three lobes.
TEI'LOBITE. (So named from its
being divided into three lobes or
principal parts.) A family of fossil
marine crustaceans, which appear
to have become extinct at the close
of the period during which the
carboniferous series was formed,
no traces of their remains having
been discovered in any strata of a
more recent period. For a long
time, fossil trilobites were con-
founded with insects, under the
name of Entomolithus paradoxus :
several names have also been given
to them, derived chiefly from the
three lobular divisions, by which
they are so characteristically mark-
ed, as well as from their being found
sometimes in a coiled, sometimes
in an extended state. By Bromel,
the trilobite was named Lapis in-
sectiferus; by Wolsterdorf, Con-
ehitus trilobus; by Hermann,

Pectunculites trilobus imbricatus ;
by Da Costa, Pediculus marinus;
by LinnaBus, Entomolithes para-
doxus ; by Baumur, Trigonella
striata; and by Wilke, Entomo-
lithus cancriformis marini. The
trilobite is often called the Dudley
fossil, from its having been first
noticed in the transition limestone
near that town. "The great
extent to which trilobites are dis-
tributed over the surface of the
globe, and their numerical abun-
dance in the places where they
have been discovered, are remark-
able features in their history.
They have been found throughout
all northern Europe, and in nu-
merous localities in Worth America,
in the Andes, and at the Cape of
Good Hope. The anterior segment
of the trilobites is composed of a
large semi- circular, or crescent-
shaped shield, succeeded by a body
composed of numerous segments
folding over each other, like those
in the tail of a lobster, and gene-
rally divided by two longitudinal
furrows into three ranges of lobes.
The nearest approach among living
animals to the external form of
trilobites is that afforded by the
genus Serolis, in the class Crus-
tacea."

TRILO'CTJLAR. (from tres, three, and
loculus, a partition, Lat.) A term
applied in botany to seed-vessels
divided into three portions or cells.

TRINU'CLETJS. The name given by
Lhwyd to a genus of trilobites
found in the Caradoc sandstone and
Llandeilo Elags.

TRI'ONTX. (trionices, pi.) A sub-
genus of fresh water testudo, be-
longing to the order Chelonia.
The soft-shelled tortoise. Several
species are mentioned. The soft-
shelled tortoises have no scales, the
shell and sternum being merely
enveloped in a soft skin ; many of
the pieces that are bony in the
tortoise being replaced by a simple

T B I

[445]

T B 0

cartilage or membrane. Fossil
remains of trionices are found in
the fresh water Wealden formations
of the secondary series. Eemains
also are abundantly found in the
lacustrine deposits of the tertiary
formations.

TBI'POLI. An admixture of silex
and clay. It has obtained its name
from having been originally brought
from Tripoli, in Barbary. It is a
mineral of a dull argillaceous ap-
pearance, occurring usually in
friable or earthy masses. Its
powder is fine, but dry and rough
to the touch, and sufficiently hard
to scratch metals, glass, &c. It is
employed for the polishing of
metals and stones. Kotten-stone
and polishing slate, the Polier-
chiefer of "Werner, appear to be
varieties of Tripoli. By recent
discoveries made by Prof. Ehrenberg
it is ascertained that tripoli is en-
tirely composed of millions of the
skeletons or cases of microspic ani-
malcules. At Eilin, in Bohemia
a stratum of tripoli extends over a
considerable space, being in some
parts fourteen feet thick. This
stone, when examined through a
powerful microscope, is found to
consist of the silicious cases of
infusoria united together without
any visible cement. From a cal-
culation made by Ehrenberg, it
would appear that in the Bilin
tripoli there are 41,000 millions of
individuals of the Gaillonella dis-
tans in every cubic inch.

TBISE'PALOTTS. (from tres, three, and
sepal.) A term used in botany for
a calyx that has three sepals.

TEI'TO^. A genus of the molluscous
order of Nudibranchiata, inhabiting
an oblong, thick, ribbed, or tuber-
culated spiral shell. The body is
oblong; mouth with an involute
spiral proboscis ; tentacula twelve,
six on either side, divided nearly
to the base, the hind one cheliferous.

TBOCHI'TA. A detached vertebra of a

radiated animal. When several
trochitse are united, so as to form
part of a column, the series is
termed an entrochite.

TKOCHO'TOMA. A genus of fossil
trochiform univalves, distinguished
from Trochus and Pleurotomaria
by having a fissure upon the last
whorl, which approaches the outer
lip but does not reach it. Six
species have been procured in the
Great Oolite near Minchinhampton,
and four in the Inferior Oolite of
the same locality, one species is
likewise recorded from the Lias of
Normandy. — Lycett.

TEO'CHUS. (trochus, Lat. a top.) A
genus of conical, spiral, thick, stri-
ated, marine, univalves, found both
fossil and recent. Aperture trans-
versely depressed, and somewhat
quadrangular ; columella oblique ;
operculum horny, with numerous
whorls. Eecent trochi are found
in the ocean at depths varying to
forty-five fathoms ; they most com-
monly, however, are met with
near the shore, creeping on rock's,
sands, and gravel. One hundred
and thirty-three species are descri-
bed in Turton's Linne. Lamarck
has separated from the genus tro-
chus of Linnaeus certain shells
possessing peculiar characters,
which he has arranged under
two new genera, namely, Solarium
and Monodonta. These genera, as
well as trochus, are comprised in
the family Turbinacea.

Very large casts of trochi are
found in Oxfordshire, Gloucester-
shire, and Sometshire.

TRONGOTHE'EIUM. The name assigned
to an extinct species of beaver,
larger than any now known, whose
fossil remains have been found in
Eussia.

TKOGONTHE'RIUM. An extinct fossil
genus of Eodents, nearly allied to,
but much exceeding in size, the
beaver. A relic of Trogontherium,
discovered by the Eev. Mr. Green,

T H 0

[446 ]

T U F

of Barton, in the lacustrine forma-
tion at Ostend near Bacton in Nor-
folk, is now in the British Museum.

TEO'PHI. The name given by Kirby
and Spence to the elementary parts
which enter into the composition
of the mouth of an insect.

TETJNCA'TION. A term used in miner-
alogy, implying that a segment is
cut off or separated from the pre-
dominant form. The term may be
applied either to an edge, or a
solid angle of a crystal, and will
leave a face more or less large in
place of the edge or angta A
truncation is said to be oblique,
when the face does not make equal
angles with all the contiguous faces.

TTJ'BER. In botany, a fleshy irregu-
lar stem produced under ground,
and distinguished from a root by
its having eyes or buds, which
the true root never possesses : the
potatoe is a familiar example.

TUBER'CULAR. In mineralogy, a term
applied to those minerals whose
unevenness of surface arises from
small and somewhat round eleva-
tions.

TUBICINE'LLA. (from tulicen, Lat. a
trumpeter.) A genus of multi valve
tubular shells, not spiral. Tubici-
nella is placed by Lamarck in the
order Sessile cirripedes. The tube
is cylindrical, and composed of six
elongated valves, laterally united.
The aperture circular, with a four-
valved operculum.

TUBI'COLA. (from tufais, a tube, and
cola, an inhabitant, Lat.) An order
of Artie ulata, comprising Serpula,
Sabella, Terebella, Amphitrite, Sy-
phostoma, and Dentalium.

TTJBI'PORA. } Organ-pipe coral, con-

TU'BIPORE. ) sisting of tubes of a
stony substance, each containing a
polype. This genus is thus de-
scribed by Parkinson: "a stony
polypifer formed by cylindrical or
oval tubes, communicating laterally
with each other." A genus of corals
or zoophytes belonging to the class

Polypifera; subregnum Cyclo-neura
or Radiata. There are several spe-
cies. In one species, Tubipora mu-
sica, the tubes are placed parallel
to each other, like the pipes of an
organ, with transverse partitions at
regular intervals : in another spe-
cies, Sertularia, the tubes are joined
together endwise, like the branches
of a tree, leaving lateral apertures
for the protrusion of the tentacula of
each separate polype. Lamarckpro-
posed to separate one species, name-
ly, Tubipora catenulata, or chain
coral, from the genus Tubipora, and
to place it in a distinct genus,
Catenipora. Tubipores are found
among the earliest traces of organic
bodies in the ancient strata. " The
principal generic character of Tubi-
pora as derived from their ascer-
tained structure, is, that the animal
substance contained in each tube so
communicates with the whole mass
by an intercurrent organization, as
to render it one connected system."

TUBI'PORITE. A fossil tubipore. Many
marbles and pebbles are beautifully
marked by sections of the inclosed
tubiporites.

TTJ'BULAR. In the shape of a hollow
tube. In botany, applied to the
florets of a compound flower, when
they form a cylindrical tube, and
are five-cleft.

TUBTJLA'RTA. (from iululus, a hollow
pipe, Lat.) A genus of corals be-
longing to the class Polypifera.
Simple or branched tubes of a horny
substance, each tube containing a
polype. Tubularias are both fresh-
water and marine.

TUBULA'RII. (tulularius, Lat.) A
family of the order Coralliferi, class
Polypi. The tubularii inhabit tubes
of which the common gelatinous
body traverses the axis, like the me-
dulla of a tree, the tubes being open,
either at their sides or summits, to
allow the passages of the polypi.

^ (tuf, Fr. thfo, It.) An earthy
precipitate deposited from water.

T U F

[ 447

T U K

TUFF. | A name applied to

TT/FA, VOLCA'NIC. j several different
substances the production of volcanic
eruptions. Generally, an aggregate
of sand, volcanic ashes, and frag-
ments of scoria and lava, united by
an argillaceous or muddy cement.
Sometimes it is composed of vol-
canic ashes and sand, transported
and deposited by rain water.

Tuff, or volcanic tufa, as dis-
tinguished from calcareous tufa,
presents various shades of grey,
brown, red, yellow, &c., or it is
sometimes spotted. Hardness mo-
derate ; fracture dull and earthy.

TUFA'CEOUS. Having the appearance
or texture of tufa.

TU'NGSTEN. (from tung, heavy, and
sten, stone, Dan.)

1. A greyish white metal, brittle,
and very hard. Specific gravity
17'4. Fusible in the most intense
heat only, its infusibility equalling
that of platinum. It has been
obtained only in the form of grains
of extreme hardness. It was dis-
covered by Scheele, and by "Werner
has been named Scheel ; by Haiiy,
Scheelin.

2. A mineral, of a grey or yellow-
ish-grey colour, occurring in Bohe-
mia, Sweden, and Cornwall, mas-
sive and disseminated. Its external
lustre is shining and splendent;
internal lustre shining and resinous.
Specific gravity from 5-57 to 6 '06.
It can be scratched with a knife,
and is easily broken. It is infu-
sible, but before the blow-pipe it
becomes opaque, and decrepitates.
By digestion in nitric acid it is
converted into a yellow powder,
which is the oxide of tungsten. It
consists of oxide of tungsten 77*75,
lime 17.60, silex 3-00, according
to Klaproth : Berzelius gives its
analysis as consisting of oxide of
tungsten 80 '24, lime 19-40. It is
the Scheelin calcaire of Haiiy and
Brongniart; the schwerstein of
Werner ; the tungsten of Kirwan.

TTTNICA'TA. (tunicatus, coated, Lat.)
The tunicated animals have no ex-
ternal shell nor internal solid parts,
but are covered with a tough, elas-
tic, homogeneous tunic, in the form
of an enveloping sac with a respi-
ratory and an anal orifice. This
exterior sac is the analogue of the
valves of conchifera, and has the
muscular fibres of the lining mantle
inserted into its inner surface.

TTJ'NICATED. Covered with one or
more tunics or membranes.

TUBBKLLA'RIA. According to Busk,
the sixth order of the class Scole-
cida.

TU'BBINATED. (turbinatus, Lat.) Of
a spiral oblong form; in conchology,
applied to shells, broad at the base,
and becoming gradually narrower
till they are pointed at the apex.

TURBINO'LIA. A genus of lamellated
stony polypifers ; free, (and in this
differing from the genus caryophyl-
lia, which is fixed,) simple, turbi-
nated or cuneiformed; longitudi-
nally striated on the exterior ; the
base pointed, the terminating cell
stelliformly lamellated and some-
times oblong.

TU'RBO. (turbo, a top, Lat.) Plural,
turbines. A genus of marine uni-
valves, found on rocks and sea-
weeds, at depths varying to ten
fathoms.

The turbo is a conoidal or slightly
turreted shell, the aperture com-
plete, rounded, and not toothed;
the margins disjoined in the upper
part ; the columella smoothed at
the base. In Turton's Linne one
hundred and fifty-one species of
tubines are described, sixty-nine of
which are indigenous to Britain.
Many species of turbines have been
described as found fossil.

TTJRKO'IS. j (twquom, Fr.) A gem

TuRQjro'isE. j of a blue or greenish
colour, and opaque, found in round-
ish masses, from the size of a pea
to that of an egg. The finest spe-
cimens are brought from Persia^

TUB

[448 ]

U M B

where they occur in small veins in
slate-clay.

TU'RBJLITE. (from turns, a tower,
Lat. and X/009, a stone Gr.) A
spiral, turriculated, multilocular
shell ; the turns contiguous, and all
visible. The chambers divided by
sinuous septa, pierced by a siphun-
cle in their disks. The mouth
round. The shells of this genus
abound in the chalk marl, gait,
and Shanklin sand. They are
extremely thin, and their exterior
is adorned and strengthened with
ribs and tubercles. The outer
chamber, which contained the ani-
mal, is large. Buckland states
that turrilites do not appear until
the commencement of the cretaceous
formations, and that having thus
suddenly appeared, they become as
suddenly extinct, at the same period
with the ammonites. De La Beche

says "aturrilitehasbeen mentioned,
though with doubt, as occurring in
the coral rag of the north of France.
Several species are enumerated as
having been discovered in the cre-
taceous group."

TUBEITE'LLA. A genus of turreted,
elongated, marine univalves, of the
family Turbinacea, found both re-
cent and fossil. Turritellae are
commonly known by the name of
screw- shells. Eecent turritellse are
found in sandy mud, at depths
varying from five to twenty fath-
oms. Fossil turritella3 are found
in the tertiary and secondary de-
posits.

TY'MPAN. ) (tympanum, Lat.) A
TY'MPANUM. ) cavity or chamber of
the ear. It is sometimes also ap-
plied to a membrane that stretches
across the cavity of the ear, called
the drum of the ear.

U

U'LNA. (ulna, Lat. from u>XeV?/, Gr.)
The cubit or large bone of the
fore-arm.

ULTBAMAEI'NE. Azure-stone ; lapis
lazuli. A pigment remarkable for
the durability of its colour. See
Lapis Lazuli.

U'MBEL. (umlella, Lat.) In botany,
a peculiar form of inflorescence:
an umbel consists of several flower-
stalks or rays, nearly equal in
length, which spread from one
common centre, and the summits
of which form a regular surface,
either level, convex or globular;
sometimes, but rarely, concave.
An umbel is either simple or com-
pound: a simple umbel has the
stalks springing from the same part
of the principal one, and each bears
but one flower. A compound um-
bel has each ray or stalk termina-

ting in another set of rays: the
carrot, parsnip, parsley, &c., fur-
nish familiar examples of compound
umbels.

UMBELLA'T^!. One of Linnaeus' natural
classes or orders of plants. The
umbellatse are plants whose flowers
grow in umbels, with five petals,
and two naked seeds, joined at top
and separated below. The parsley,
fennel, &c., are examples.

UMBELLI'FEILE. A large order of
plants, characterized by their flowers
being in umbels. Calyx entire or
five-toothed. Petals five, usually
inflexed at the point. Stamens
five, alternate with the petals.
Ovary two -celled. Fruit consisting
of two carpels, separable from a
common axis. Seed pendulous.
Herbaceous plants with fistular
stems.

U M B

[449 ]

UNI

UMBI'LICATED. (umlilicatus, Lat.) In
conchology, a term applied to such
shells as have a depression in the
centre, like a navel. Univalves
that have the umbilicus covered in
a greater or less degree by a thin
process, are termed sub-umbili-
cated.

UMBILI'CUS. (umbilicus, Lat.) The
navel. In conchology, a circular
perforation in the base of the lower
whorl, or body, of many spiral
univalves, and common to most of
the Trochi, in some of which it
runs from the base to the apex.

U'MBO. (umlo, Lat.) A boss or pro-
tuberance. In conchology, that
point of a bivalve shell situated
immediately above the hinge. This
word makes umbones in the plural.

U'MBONATED. Bossed ; knobbed in the
centre.

UNCONFO'RMABLE. In geology, a term
applied to a stratum or strata lying
in a different plane from the sub-
jacent strata upon which they rest.
Strata not lying parallel with those
beneath them. Supposing certain
strata to have been upheaved, so
that their inclination is at an angle
with the horizon, or even vertical,
such strata may all be, notwith-
standing, conformable one with
another; if, however, upon these
tilted strata, fresh strata be depo-
sited, the more recent strata lying
horizontally upon the subjacent
vertical or inclined strata, then the
superjacent strata are termed un-
conformable.

UNCONFO'RMABLY. Not being in the
same plane with those upon which
they are deposited. Strata lie
unconformably when placed upon
others having a different line of
direction or inclination.

U'NCTUOUS. (unctus, Lat.) Greasy;
soapy to the touch. In mineralogy
certain minerals are said to be
unctuous ; soap-stone is a good
example.

UNCTUO'SITY. Greasiness. A character

belonging to certain minerals,
which is very useful in assisting to
distinguish them. Some minerals,
when the finger is passed over their
surface, or their powder is rubbed
between the finger and thumb, feel
as if they were coated with some
greasy matter. The sensation is
different from that produced by
mere smoothness of surface.

UNDERLIE. A term used in mining,
or by miners. In speaking of the
inclination of a fault it is better,
says Jukes, not to use the term
"dip" as if it were a bed, but to
adopt that of "hade," or "un-
derlie."

U'NGUAL. (from unguis, a nail or
claw, Lat.) A name applied to
such bones of the feet as have
attached to them a nail, claw, or
hoof.

U'NGUICAL. The name given to the
claw-bone of certain animals.

UNGUI'CULATED. Clawed; possessing
claws.

U'NGTTLATE. (from ungula, a hoof,
Lat.) Shaped like the hoof of a
horse.

U'NGULITE GRIT. A member of the
Eussian Lower Silurian rocks, and
so named from a peculiar fossil it
contains: it is a white or ferru-
ginous sandstone, not much ex-
ceeding 100 feet in tfiickness.

UNICA'PSULAR. (from unus, one, and
capsula, a capsule, Lat.) Having
one capsule only to each flower.

UNILO'CTJLAR. (from unus, one, and
loculus, a cell or partition. ) Having
one chamber or cell only. In con-
chology, applied to shells which
are not divided by septa into cham-
bers. In botany, applied to seed
vessels not separated into cells.

U'NIO. (unio, Lat. a pearl.) A genus
of freshwater bivalve shells, placed
by Lamarck in the family Nayades,
and by Cuvier in the family Myti-
lacea. Uniones are equivalve, in-
equilateral, transverse, internally
pearly, externally covered with an

2 M

UNI

[450]

U P P

epidermis, bivalves ; they are com-
monly called freshwater muscles.

UNIVALVE, (from unus, one, and
vaka, a shell, Lat.) A shell which
is complete in one piece. The Lin-
nasan arrangement of shells consists
of three orders, namely, multi valves,
bivalves, and univalves. Univalves
are far more numerous than either
multivalves or bivalves, both in
genera and species.

UNMA'LLEABLE. That cannot be ex-
tended by hammering; that cannot
be hammered out into plates or
laminae.

UNORGANIZED. Having no parts in-
strumental to the motion or nour-
ishment of the rest.

UNSTRA'TIFIED. A term applied to
rocks that are not stratified, or not
arranged in strata. "When no traces
of beds can be detected, and the
rock merely forms a great mass of
mineral matter, without other lines
than those of cleavage, it is said to
be unstratified. De la Beche ob-
serves, "the terms stratified and
unstratified have been commonly
considered as respectively synony-
mous with aqueous and igneous.
Practically, this division is highly
valuable; but theoretically, it is
not so satisfactory, at least, if we
are to infer that all rocks divided
into tabular masses, one resting on
another, must have been deposited,
either chemically or mechanically,
from water. We should be careful
not to couple too far stratification
with aqueous deposition, as sheets
of igneous rocks may cover pre-
existing sheets of similar rocks,
and the result be stratification."

UPPER GREENSAND. (Glauconie Cray-
erne, Fr. (Moritische Kreide, Germ.)
A member of the cretaceous group.
An arenaceous rock, for the most
part very calcareous, containing
grains of silicate of. iron. The
upper greensand is a marine deposit,
consisting of marly stone and sand,
with numerous green particles, fre-

quently including concretions of
chert, and, in some places, beds of
stone. From the application of
portions of this deposit in the con-
struction of ovens, furnaces, &c.,
it has obtained the name of Fire-
stone. The situation of the upper
greensand is between the chalk
without flints above, and the gault
below. Its thickness is about 100
feet.

UPPER LUDLOW ROCK. A sub- division
of theLudlow formation, thus named
by Sir R. Murchison. This great
explorer of the silurian rocks says,
"this sub-division of the Ludlow
formation consists essentially of
thin bedded, lightly coloured, and
very slightly micaceous sandstones,
in some parts highly argillaceous,
and in others so calcareous as to
assume the character of impure
limestones. When deeply cut into,
these beds are of greenish-grey or
bluish-grey tints, but they rapidly
weather to an ashen or, more rarely,
to a rusty-brown colour."

UPPER SILURIAN ROCKS. Sir E. Mur-
chison divides the Silurian rocks
into upper Silurian and lower Silu-
rian. The upper Silurian comprise
the Ludlow formation, sub-divided
into the upper Ludlow, the Aymes-
try limestone, the lower Ludlow,
the Wenlock limestone, and the
"Wenlock shale : the lower Silurian
rocks comprise the Caradoc sand-
stones and the Llandeilo flags.
" The two formations," he says, "of
Ludlow and "Wenlock, possess so
much of a common lithological
aspect, and offer such intimate
passages from one to the other in
the distribution of the organic
remains, that they form a very
distinct natural sub-group, which
I have termed upper Silurian."

U'PPER TE'RTIARY STRA'TA. These
strata are considered to be of more
recent origin than those usually
denominated tertiary, and, by some
geologists, have been termed qua-

U E A

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V A L

ternary. They are supposed to be
of more recent origin than any of
the strata composing the formations
of the London and Paris basins.

U'KANITE. An ore of Uranium of a
black or green colour, called also
Pechblende.

URA'NIUM. A metallic substance of a
grey colour, obtained with great
difficulty from a mineral called
pechblende. It is infusible. Spe-
cific gravity 9'0 to 9 "50. It is
found in Saxony and in Cornwall.
It imparts a deep orange colour to
the enamel of porcelain.

UECE'OLATE. (from urceolus, Lat. a
water-pitcher.)

1. In conchology, a term applied
to a shell that swells in the middle,
and is therefore supposed to bear a

resemblance to a water-pitcher.
2. In botany, applied to a calyx or
corolla swelling out like a pitcher.

U'BCHIN. The hedgehog. The name
of sea-urchin has been given to the
echinus.

U'TBICLE. (utriculus, Lat. a little
bottle.) In botany, a term applied
to a species of capsule resembling a
small bladder, or a capsule of one
cell, which never opens by valves,
and drops with the seed. It is
thin and transparent, and is more
frequently considered to be the
external coat of the seed than a
real capsule.

UTEI'CTJLAR. Resembling a utricle in
form or shape. The pelvis of
apiocrinites is of a tumid utricular
form.

YA'GTNATED. (from vagina, a sheath,
Lat.) A term used in botany,
sheathed.

VAGINOPE'NNOUS. (from vagina, a
sheath, and penna, a wing, Lat.)
Sheath-winged ; having the wings
covered with hard cases.

VAGI'NTTLA. A genus of minute pyra-
midal shells, known only as fossils,
and found in the tertiary strata
near Bordeaux.

VAI/LEY OF ELE'VATION. This name
is given by geologists to a valley
which seems to have originated in
a fracture of the strata, and a
movement of the fractured part
upwards, so that the strata dip
from the valley on either side.
Probably a very large proportion
of mountain valleys might be ar-
ranged under this head; but, at
present, geologists seem to have
confined the application of the term
to those which are bounded by hills
of moderate height.

VAI/LEY OF DENUD'ATION. A name
given by geologists to any valley
where the strata are not far re-
moved from the horizontal position
on either side, and of which the
former continuity cannot be
doubted.

VALVA'TA. A genus of small fresh-
water univalves belonging to the
family Peristomata. Yalvatae are
found both recent and fossil.

YALVE. (valva, Lat. valve, Pr. valva,
It.)

1. In conchology, the shell. When
the whole shell of the animal is in
one piece, it is called a univalve ;
when there are two shells, or the
shelly covering consists of two
pieces, as in the oyster, muscle,
&c., they are called bivalves; and
when the covering consists of more
than two pieces, multivalves.

2. In anatomy, a folding door or
lid attached to a hollow vessel by
means of a hinge, which allows the

VAN

[452]

V E I

valve to open in one direction only
for the passage of fluids, and pre-
vents their retrograde motion, or
regurgitation. Thus there are
valves in the heart ; valves in the
veins; valves in the lympha-
tics, &c.

VA^A'DIUM. A metal discovered by
Sefstrom, in Sweden, and thus
named after Vanadis, a Scandina-
vian deity. Its properties are not
yet known.

VA'BIEGATED SAND'STONE. The New
Ked Sandstone of the English ; the
Gres Bigarre of the French, and
the Bunter Sandstein of the German
geologists. For a description see
New Red Sandstone.

VAEI'ETY. (varietas, Lat.) A sub-
division of species, arising from
accidental, or unimportant and
trifling, differences.

VAEI'OLITE. (from variolw, Lat.) The
name given to an amygdaloidal or
porphyritic rock, merely in conse-
quence of its spotted appearance.

VA'SCULAE. (from vasculumt Lat. a
little vessel.) Containing vessels
or tubes ; full of vessels within
which the fluids are confined, and
by which their course and their
velocity are regulated.

VEGETABLES. The first appearance of
vegetable existence may be discov-
ered in the transition slate, which
contains impressions of algse or
sea- weeds. A few fronds of ferns
have been found in some of the
transition rocks. "It appears,"
says Buckland, " that nearly at the
same points in the progress of
stratification, where the most stri-
king changes take place in the
remains of animal life, there are
found also concurrent changes in
the character of fossil vegetables."

VEIN, (vena, Lat.)

1. In anatomy, elastic tubes perva-
ding every part of the body, and
conveying dark or venous blood
from the arteries to the heart.
The veins are larger and more

numerous than the arteries, and
may be compared to rivers, which,
collecting all the water that is not
imbibed by the soil, and reconvey-
ing it into its general receptacle,
the ocean, perform an analogous
office in the economy of nature.
2. In geology and mineralogy,
fissures in rocks filled up by
mineral or metallic substances dif-
fering from the rocks in which
they are situated. Mineral reposi-
tories of a flat or a tabular shape,
which in general traverse the
strata of mountains, crossing the
strata, and having a different di-
rection from them, and filled with
mineral matter, differing from the
nature of the rocks in which they
occur. Bakewell says, " perhaps
the reader may obtain a clearer
notion of a metallic vein, by first
imagining a crack or fissure in the
earth a foot or more in width, and
extending east and west on the
surface, many hundred yards.
Suppose the crack or fissure to
descend to an unknown depth, not
in a perpendicular direction, but
sloping a little to the north or
south. Now, let us again suppose
each side of the fissure to become
coated with mineral matter of a
different kind from the rocks of
which the fissure is made, and then
the whole fissure to be filled by
successive layers of various me-
tallic and mineral substances ; we
shall thus have a type of a metallic
vein. Its course from east to west
is called its direction, and the dip
from the perpendicular line of
descent its hading. Thus it is said
to hade or dip to the north or
south."

Veins occur principally in the
primary and transition rocks, but
they are also found in the lowest
of the secondary series.

As regards the geographical dis-
tribution of mineral veins, it is an
established fact, that while exten-

V E I

[453 ]

V E N

sive plain countries are totally de-
stitute of them, there are few
mountainous districts in which
they are not abundantly found.
It has been very generally ob-
served that the character of metal-
liferous veins changes with the
structure of the rock through
which they pass. If the direction
of a vein approaches to a vertical
plane, it is called a rake vein, if to
the horizontal, a pipe or flat vein.

The depth to which the metallic
veins descend is not known, all
large veins continuing beyond the
reach of the deepest mine. They
frequently contain totally different
ores at different depths.

Veins vary in width from less
than an inch to thirty feet and
upwards ; sometimes the same vein
at one part contracting, so as to
be almost lost, and then expanding
to an immense width.

Werner supposed that veins had
become filled by matter descending
into them from above, in a state of
aqueous solution : Hutton, on the
other hand, imagined that their con-
tents were injected from below, in a
state of igneous fusion. A third
hypothesis refers the filling of veins
to a process of sublimation from
subjacent matters of intensely
heated mineral matter, into aper-
tures and fissures of the superin-
cumbent rocks. A fourth hypo-
thesis attributes these metallic
collections to segregation, or in-
filtration. Buckland says, " What-
ever may have been the means
whereby veins were charged with
their precious contents ; whether
segregation or sublimation were
the exclusive method by which the
metals were accumulated ; or,
whether each of the supposed
causes may have operated simul-
taneously or consecutively in their
production ; the existence of these
veins remains a fact of the highest
importance to the human race :

and although the disturbances, and
other processes in which they
originated, may have taken place
at periods long antecedent to the
creation of our species, we may
reasonably infer, that a provision
for the comfort and convenience of
the last, and most perfect creatures
He was about to place upon its
surface, was in the providential
contemplation of the Creator, in
His primary disposal of the phy-
sical forces, which have caused
some of the earliest and most
violent perturbations of the globe.' '

YEIN-STONE. 1. The earthy, stony,
saline, or combustible substance,
which contains the ore, or is
mingled with it, without being
chemically combined, is called the
gangue, or vein-stone.
2. Vein- stones are the different
stony substances with which the
ore is intermixed, and which as a
whole constitute the vein. Werner
was of opinion that in the same
vein the parts of the vein-stone
nearest to the Saalbande are the
oldest, those in the middle the
most modern, and the intermediate
parts of a middle age.

YENERICA'RDIA. A genus of equi-
valved, inequilateral, marine, ob-
long bivalves; ribbed longitudinally
on the outside; two thick hinge-
teeth disposed obliquely, and in
the same direction : muscular im-
pressions two. Venericardia3 are
found recent and fossil. The
recent are met -with at depths
of the ocean varying to fifty
fathoms, in mud and sands. Fossil
venericardia3 are found in the se-
condary and tertiary formations.

VE'NTEICLE. (from ventriculus, Lat.)
A chamber or cavity ; the stomach.
A term applied to different cavities
of the body. The heart contains
two chambers distinguished as the
right and left ventricles, as well as
two others, termed auricles. Cer-

YEN

C 454]

V E R

tain cavities found in the brain are
also called ventricles.

VE'NTEICOSE. } 1. In botany, applied

VE'JSTTEICOTJS. j to parts of plants
which are distended, bellied, or
swelling out in the middle.
2. In conchology, applied to shells,
inflated, or swelling in the middle.

VENTEI'CTTLITE. A zoophyte found
fossil in flints and in the chalk.
The ventriculite, when living,
must have been of a cyathiform
figure, and composed of a tough,
jelly-like substance, capable of ex-
pansion and contraction. The gen-
eral form of the animal appears to
have been that of a hollow inverted
cone, having numerous ramose
fibres proceeding from the base, by
which it was attached to other
bodies. Externally, it was compo-
sed of a reticulated integument,
which seems to have been capable
of expanding and contracting ac-
cording to the impressions it re-
ceived ; and, internally, it posses-
sed a surface covered with the
apertures of numerous tubuli ; in
all probability the openings of
vessels, by which nutrition was
effected. The smaller extremity
was attached to the rock by root-
like processes; the outer tissue
consisted of a net work of cylindri-
cal, perhaps tubular, fibres ; the
inner surface of the funnel-like
cavity was studded with polypi-
ferous cells or openings. The spe-
cimens enveloped in flint are usually
of a cyathiform or turbinated shape,
while those imbedded in chalk are
more frequently expanded into a
broad circular disk. When con-
tracted into a cylindrical form, the
ventriculite is from one to six
inches in length : when expanded,
its diameter generally exceeds nine
inches : the thickness of its sub-
stance is rarely more than 0'2 inch.

VE'NTJS. (from Venus, the goddess of
beauty.) A genus of exceedingly
beautiful marine bivalves. Equi-

valve, inequilateral, subglobose,
transverse shells, the frontal mar-
gin flattened, with incumbent lips;
hinge with three teeth, all of them
approximate, the lateral ones di-
vergent at the tip. The middle
tooth, which is sometimes bifid, is
placed straight, and the one on
each side obliquely.

Cuvier places Venus in the family
Cardiacea. The common clam is a
true Venus.

VEBDE-ANTI'Q.UE. A very beautiful
marble, highly prized, and used
for ornamental purposes. It is an
aggregate of serpentine and white
crystallized marble, irregularly
mingled.

VE'EETJCOSE. j (yerrucosus, full of warts,
VE'EETJCOTJS. ) from verruca, Lat.)

1. In entomology, applied to the
surface of insects, when studded
with large smooth elevations, re-
sembling warts.

2. In conchology, applied to shells
beset with excrescences resembling
warts.

3. In botany, applied to the surface
of stems, beset with hard tubercles
or warts.

VEBSICO'LOUEED. Displaying different
colours, indeterminately restricted.
VE'ETEBEE. } (vertebra, Lat.) A bone
VE'BTEBBA. ) of the spinal column,
or back-bone. The different ver-
tebras composing the back-bone are
distinguished into curvical, dorsal,
and lumbar. The vertebral column
or spine, from the constancy with
which it has been found in all
animals of this type, and from the
uniformity of plan with which,
amidst endless variations, it is mo-
delled, has been chosen as the dis-
tinctive character of all that greal
assemblage of individuals denomi-
nated Vertebrata. In man, the
number of vertebra is twenty-four,
namely, seven curvical, twelve dor-
sal, and five lumbar. In differenl
animals the number of vertebras
varies exceedingly; the vertebra]

YE £

[455 ]

YES

column of the Ichthyosaurus con-
sisted of more than one hundred
joints. The cervical vertebrae alone
of the Plesiosaurus were about
thirty-three in number. In birds
the number varies from nine to
twenty- three, and in living reptiles
from three to eight. In the Moso-
saurus, the whole number of verte-
brae amounted to one hundred and
thirty- three.

YEETEBEA'TA. The whole animal
kingdom has been distributed into
four great divisions, namely, Yer-
tebrata, Mollusca, Articulata, and
Radiata. The vertebrate section
of the animal kingdom contains
five great classes, all agreeing in
these seven particular points: first,
in the possession of a brain and a
spinal chord, and these enclosed in
a skull and vertebral column ; se-
condly, in the possession of an in-
ternal bony skeleton; thirdly, in
the number of their limbs not ex-
ceeding four; fourthly, in the
possession of organs serving the
purposes of hearing, seeing, smell-
ing, and tasting; fifthly, in having
a mouth with two jaws, placed one
above the other, and not on oppo-
site sides; sixthly, in having a
muscular heart, and circulating red
blood ; seventhly, in the individual
distinctiveness of the sexes. In
the ascending series, the first of
the true vertebrated animals is the
class of Fishes ; then follows Am-
phibia, comprehending the various
forms of frogs, toads, and tritons;
the third class is the Reptiles. These
three classes are all cold-blooded.
The fourth class comprises the
birds ; these form the first class in
the ascending series of hot-blooded
animals; the fifth, or highest class,
comprehends Mammalia, and in-
cludes man.

VE'ETEBRATED. } (vertebratus, Lat.)

VE'RTEBEATE. ) Possessing an osse-
ous spinal column.

YE'ETEX. (vertex, Lat.) The crown,

or top of the head; the summit.
In conchology, in some shells the
most prominent part, in others the
apex.

VE'ETICIL. (vertillum, Lat. a whirl.)
In botany, a little whorl; thus
when, instead of two opposite
leaves, three or more are produced
from points forming a ring on the
stem, such ring is termed a verticil.

VEETICI'LLATE. ] (verticillatus, Lat.)

YEETICI'LLATED. j "Whorled; grow-
ing in rings or whorls. Leaves
produced from three or more points,
forming a ring on the stem, are
called verticillate leaves. Yerti-
cillate leaves are considered as
being produced by the non-deve-
lopement of several adjacent inter-
nodia.

YE'SICLE. (vesicula, a little bladder,
Lat.)

1. A small bladder filled with serum.

2. A small membranous cavity,
either in animals or vegetables.
The simplest and apparently the
most elementary texture met with
in vegetables is formed of exceed-
ingly minute vesicles, the coats of
which consist of transparent mem-
branes of extreme tenuity. These
vesicles vary from the one- thou-
sandth to the thirtieth of an inch
in diameter.

YESI'CULAB. Consisting of vesicles;
containing vesicles; full of small
cavities, hollows, or interstices.

YE'STIBULE. (vestilulum, Lat.) The
name given to a cavity of the
internal ear.

YESTJ'VIAN. (from Vesuvius.} The
Idocrase of Haiiy ; the Yesuvienne
of Brochant. Pyramidal garnet.
A mineral of different shades of
green, brown, red, and sometimes,
though rarely, of a blue colour,
occurring in granular distinct con-
cretions, crystallized, and massive.
The primitive form is a four-sided
prism with square bases, and one
side of the base is to the height
nearly as 13 to 14; hence it differs

VEX

[456 ]

VOL

but little from a cube, and is divi-
sible into triangular prisms, for the
integrant particles. It yields to
cleavage readily, parallel to all its
planes, with sufficient brilliancy to
obtain incidences of 90' by the
reflective goniometer in every di-
rection. Haiiy has described eight
modifications of its primitive form.
It is somewhat harder than quartz.
Specific gravity from 3 '2 to 3-4.
It is often translucent, sometimes
transparent, and sometimes nearly
or quite opaque. It possesses dou-
ble refraction. Fracture uneven,
inclining to small conchoidal. Be-
fore the blow-pipe, it fuses easily
into a yellowish translucent glass,
which afterwards becomes black.
Its constituents vary, in some de-
gree, according to the localityjwhence
it has been obtained. Klaproth
obtained from a specimen from the
neighbourhood of Vesuvius, silex
35-50, lime 33-00, alumine 22-2,
oxide of iron 7-50, oxide of manga-
nese 0'25. It is found abundantly
in the vicinity of Mount Vesuvius,
in the ejected masses, where its
crystals line the cavities of volcanic
rocks, accompanied by garnet, horn-
blende, melanite, mica, and icespar,
from which circumstance it has
obtained its name, and in primary
rocks in Ireland, Scotland, and
other parts of Europe.
VEXI'LLTJM. i (vexillum, a standard, or
VE'XIL. j banner, Lat.) In bo-
tany, the upper large petal of a
papilionaceous flower.
VI'LLI. (from viUus, a hair, Lat.)

1. In anatomy, fine small fibres,
resembling a covering of down.

2. In botany, fine downy hairs,
covering fruits, flowers, and plants.

VI'LLOTTS. (villosm, Lat.) Downy;

pubescent; shaggy.
VIO'LET QUARTZ. See Amethyst.
VI'SCID. } (viscidus, Lat.) Glutinous;
Vi'scous. ) tenacious; clammy.
Vi'scus. (yiseus, Lat.) In the plural,

viscera ; this term is generally ap-

plied to the organs connected with
digestion; sometimes to the bowels
only. Any organ of the body may
be denominated a viscus.
VI'TREOUS. (vitreus, Lat.) Glassy;
resembling glass.

1. In mineralogy, a term used to
denote a particular lustre of some
minerals, resembling that of glass.

2. In anatomy, a term applied to
one of the humours of the eye.
The vitreous humour occupies more
than three-fourths of the globe of
the eye ; it is contained in an ex-
ceedingly delicate texture of cellular
substance, and is situated behind
the crystalline lens.

VI'TREOUS SAND TUBES. See Fulgorite.

VI'VIANITE. The Vivianit of Werner ;
the Per Phospate of Haiiy. Phos-
phate of iron. A mineral of a green
or blue colour. Its constituents
are, protoxide of iron 47 -5, phos-
phoric acid 32, water 20.

VIVI'PAEOUS. (viviparus, Lat. from
vivus, alive, and pario, to bring
forth; vivipare, Fr.) Animals are
termed viviparous in which no egg,
properly so called, is formed, but
bring forth their young alive and
perfect.

VOLCA'HTC PRODUCTIONS. These are
numerous and diversified. Lava,
scoria, enamel, and glass, comprise
by far the most important and
interesting volcanic productions.
The different states of lava, whether
vitreous, compact, or scoriaceous,
depend on the different circum-
stances under which it has cooled.
Aqueous vapour is in general very
abundant. Volcanic products are
naturally divisible into two great
classes; sub-aerial, and sub-aque-
ous. The first, being in many
respects open to our investigation,
is to a considerable extent under-
stood. The second, for the most
part hidden from examination, is
necessarily but little known, though
recent observation has thrown some
light upon it. " Various classifi-

VOL

[457]

VOL

cations of mineral volcanic pro-
ducts have been proposed, among
which the division into Trachytic
and Basaltic seems to be that most
commonly adopted ; trachyte being
considered as essentially composed
of felspar, and containing crystals
of glassy felspar; while basalt is
supposed to be essentially composed
of felspar, augite, and titaniferous
iron. Lavas, however, present such
various mixtures of different mine-
rals, that exact classifications of
them would appear exceedingly
difficult." — De la Beche. The
principal gases hitherto detected
consist, according to Dr. Daubeny,
of muriatic acid gas, sulphur com-
bined with oxygen or hydrogen,
carbonic acid gas, and nitrogen.
The sublimations of Vesuvius are,
according to Sir H. Davy, chloride
of sodium, chloride of iron, sulphate
of soda, muriate and sulphate of
potash, and a small quantity of
oxide of copper. The principal
metallic substances in volcanic rocks
are iron and titanium ; but ores of
antimony, copper, and manganese,
have sometimes been found in the
craters of volcanoes. Tellurium,
gold, and mercury are also said
to occur in some volcanic rocks.
The island of Ischia, which is
entirely volcanic, contains a mine
of gold.

VOLCA'NIC BOCKS. These are not
deemed synonymous with Plutonic
rocks. While the Plutonic rocks
are supposed to have been formed
by igneous action at great depths,
the Volcanic have risen up from
below, and have cooled from a
melted state upon or near the sur-
face. Volcanic rocks belong to
every period.

VO'LCANITE. Another name for augite.

VOLCA'NO. (from Vulcan, the god of
fire.) An opening in the earth's
surface made by internal fire. Vol-
canoes exist in all quarters of the
globe, and, according to Jameson,

about one hundred and ninety-three
active volcanoes have been observed ;
of which 13 belong to Europe and
its islands, — 66 to Asia and its
islands, — 8 to the islands of Africa,
— and 106 to America and its is-
lands. Volcanoes have been long
considered in the light of safety
valves, and this was the opinion
entertained of them by Strabo, and
it can scarcely be doubted that the
tranquillity of the incandescent fluid
mass, composing the earth's centre,
is owing to these numerous vents
for the passage of steam, &c. Al-
though volcanoes generally exist
in the neighbourhood of the sea,
yet this is not invariably the case,
as was once supposed. In central

• Asia there is a volcanic region with
an area of 2500 square geographical
miles, at a distance of upwards of
300 leagues from the ocean.

VO'LVA. (volva, Lat.) In botany, a
species of calyx. A term applied
to a membranous wrapper or cover-
ing of the fungus tribe, which
conceals their parts of fructifica-
tion: in due time it bursts, and
forms a ring upon the stalk.

VOLVA'RIA. A genus of cylindrical
convoluted shells known only in a
fossil state. The spire is not ex-
truded; aperture narrow, extending
the length of the shell : the colu-
mella plicated at its base: outer
lip dentated. Volvaria approaches
very near to Bulla cylindrica.

VOLU'TA. A genus of simple marine
univalves, found in sands and mud
at depths varying from seven to
fourteen fathoms. Two species of
voluta, V. luctator and V. bicorona
are described as occurring in the
London clay ; one species V. lucta-
tor in the Bognor sandstone ; and
one species, V. ambigua, in the
chalk marl.

VOLITION. A spiral wreath or turn.
The wreaths or turnings of the
shells of univalves are termed vo-
lutions.

VOL

[458]

WAR

VO'LVOX. (volvox, Lat. from voho, to
roll.) A genus of globular animal-
cules. To the presence of one
species of volvox, the volvox glo-
bator, a loricated animalcule, and
to its great abundance in such situ-
ations, pools of stagnant water owe
their green colour.

YI/LCANIST. One who supports the
Vulcanian theory, namely, that all
rocks are of igneous production.
The Yulcanists were opposed to the

Neptunians, who, on the other
hand, maintained that all rocks
were of aqueous origin.

YUL'CANIAN THE'OEY. That theory
which explained the formation of
all rocks by the agency of fire.

YTJ'LPINITE. A mineral of a greyish-
white colour; thus named from its
being found at Vulpino, in Italy.

YULVA. (Lat.) In conchology, a
spatulated mark in shells of the
Yenus tribe.

W

WACKE. | A name given by the Ger-
WACKE'. ) mans to a soft earthy
basalt, to which it is nearly allied,
and of which it may be deemed a
variety. Its colours are greenish
grey, sometimes passing into black-
ish green, brown, and greyish
black, with sometimes a shade of
yellow or red. It is invariably
opaque. It occurs in amorphous
masses, compact or vesicular.
Fracture uneven, or slightly con-
choidal. Hardness moderate. It
is easily broken, and may be cut
by a knife. Specific gravity from
2-5 to 2-8. Before the blow-pipe it
fuses into an opaque, porous mass.
It appears to be intermediate be-
tween clay and basalt, often passing
into basalt. It does not adhere to
the tongue, which circumstance
distinguishes it from clay, nor will
it form a paste with water. It
does not, as does marl, effervesce
with acids. Wacke is included
among the trap rocks. When
wacke, being vesicular, contains
within its cavities calcedony,
agates, &c. it forms a variety of
amygdaloid. It is found more
abundantly in Germany than any
other country, but it is not confined
to Germany.

j Another name for black-

WADD. ) lead.

WADD BLACK. A name given to the
earthy manganese of Devonshire:
it is a hydrate of manganese, and
has the peculiar property of taking
fire when dry, moderately heated,
and mixed with linseed oil.

WAEM-BLOODED ANIMALS. In the as-
cending series of the four great
divisions of the animal kingdom,
the highest, or vertebrata, alone
contains what are called warm-
blooded animals. Of this division,
consisting of five classes, two classes
only, namely, aves, or birds, and
mammalia, are warm-blooded ; the
remaining three are cold-blooded.
In warm-blooded animals the cir-
culation is two-fold, there being, in
fact, two hearts, perfectly distinct,
and separated by thick partitions,
which do not permit any direct
transmission of fluid from one to
the other. These two hearts are
joined together, and enclosed with-
in one capsule or envelope. The
following is the course of circula-
tion in warm-blooded animals.
From the left ventricle the blood
is propelled into the aorta, the great
artery of the body, to be by it for-
warded into all the arterial ramifi-

WAT

L 459 ]

W E A

cations of the whole system ; from
these arteries it passes on through
the veins into the vense cavse, and
by them is carried into the right
auricle; from the right auricle it
passes into the right venticle, and
by the right ventricle is propelled
into the piilmonary arteries, to be
conveyed through the lungs, in its
passage through which it becomes
aerated, loses its dark and assumes
a florid colour, and is once more
arterial blood ; it then passes into
the pulmonary veins, and is con-
veyed into the left auricle, whence
it is forced into the left ventricle,
and once more into the aorta.

WA'TER. (wasser, Germ.) When
pure, water is transparent, and
destitute of colour, taste and smell.
The specific gravity of water is
always supposed = 1*000, and it
is made the measure of the specific
gravity of all other bodies. When
water is cooled down to 32° Fah.
it assumes the form of ice. When
heated to the temperature of 212°
Fah. it boils, and is converted into
steam. Pure water consists of
two parts of hydrogen and one of
oxygen.

WA'VED. Variegated; undated.

1. In botany, applied to the mar-
gins of leaves, when bordered alter-
nately with numerous minute seg-
ments of circles and angles.

2. In entomology, applied to insects
when the margin of the body is
marked with a succession of arched
incisions.

WA'VELLITE. A rare mineral, first
discovered in Devonshire by Dr.
Wavell, and named after him. Its
colours are either pure white or
white tinged with grey, green, or
yellow ; lustre silky. Specific gra-
vity from 2-25 to 2'70. It consists
essentially of alumine, being com-
posed of alumine 71 '5, water 28*0,
oxide of iron 0'5. Sometimes a
trace of silex and lime is present,
and Sir H. Davy discovered in

Wavellite the presence of fluoric
acid.

WEALD, (from wold, Germ, a wood.)
The name given to a valley, or
tract of country, lying between the
North and South Downs of Kent
and Sussex. In some of the older
publications the Weald is called
the Wild. At the close of his
account of the organic remains of
Tilgate Forest, Dr. Mantell says,
"it may be remarked that the
vast preponderance of the land and
freshwater exuvia3 over those of
marine origin, observable in these
strata, warrants the conclusion that
the Hastings or Wealden beds were
formed by a very different agent
from that which effected the depo-
sition of the Portland limestone
below, and the sands and chalk
above them. Whether the land of
that time were an island or a con-
tinent, may not be determined ;
but that it was diversified by hill
and valley, and enjoyed a climate
of a higher temperature than any
part of modern Europe, is more
than probable. Several kinds of
ferns appear to have constituted
the immediate vegetable clothing
of the soil. But the loftier vege-
tables were so entirely distinct from
any that are now known to exist
in European countries, that we
seek in vain for anything at all
analogous, without the tropics. The
forests of Clathraria and Endogenitae
(the stems of which, like some of
the recent arborescent ferns, pro-
bably attained a height of thirty or
forty feet,) must have borne a much
greater resemblance to those of tro-
pical regions, than to any that now
occur in temperate climates. Turtles
of various kinds must have been
seen on the banks of its rivers and
lakes, and groups of enormous cro-
codiles, basking in the fens and
shallows. The gigantic Megalo-
saurus, and yet more gigantic Igu-
anodon, must have been of such

W E A

prodigious magnitude, that the ex-
isting animal creation presents us
with no fit objects of comparison.
Imagine an animal of the lizard
tribe, three or four times as large
as the largest crocodile, having
jaws, with teeth equal in size to
the incisors of the rhinoceros, and
crested with horns; such a creature
must have been the Iguanodon !"
WEALD-CLAY. (Argile veldienne of
Brongniart ; Wealdthon, Germ.)
A tenacious blue clay, containing
subordinate beds of sandstone and
shelly limestone, with layers of
septaria of argillaceous ironstone,
forming the subsoil of the wealds
of Sussex and Kent, and separating
the Shanklin sand from the central
mass of the Hastings beds. — Dr.
ManteWs Geology of the South- east
of England.

The "Weald-clay contains argil-
laceous iron-stone, occurring in
regular beds. This ore of iron
was so valuable, when it was the
practice to use wood-charcoal for
smeltiDg, that furnaces were for-
merly numerous along the verge of
the Weald. The thickness of the
Weald-clay is estimated at 150 or
200 feet in Western Sussex.
WEA'LDENFOEM'ATION. } TheWealden
WEA'LDEN STB' ATA. ) formation,
group, or strata, have been sepa-
rated into three principal divisions.

1. The Wealden clay, above de-
scribed.

2. The Hastings sands: grey, white,
yellow, and reddish-brown sands,
and friable sandstone, passing into
limestone.

3. The Purbeck beds, called also
Asburnham beds, consisting of grey
limestone, alternating with blue
clay and sandstone shale. The
whole of these are freshwater or
fluviatile deposits. The wealden
is covered by the marine cretaceous
system, and reposes upon the upper-
most member of the oolite, which
is also a purely marine deposit.

[ 460 ] W E A

This intercalation, says Sir C. Lyell,
of a great freshwater formation be-
tween two others of marine origin
is a remarkable fact, and attests, in
a striking manner, the great extent
of former revolutions in the position
of sea and land. From these and
other data, he says, it seems a legi-
timate deduction that the marine
formations of an antecedent period
(that of the oolite) had become
land throughout a portion of the
space now occupied by the South
of England and the opposite coast
of France ; and that this land then
sunk down, with its forests, and
became submerged beneath the
waters of a great river. The
country may then have continued
to subside, until a thickness of two
thousand feet of fluviatile sediment
had been gradually accumulated;
and this deposit, or delta, by a
continuation of the same depressing
operations, may, in its turn, have
become buried deep beneath the
ocean of the chalk. Dr. Mantell
may be considered the great geo-
logical champion and hero of the
Wealden, for to his indefatigable
exertions in that field, are owing
some of the most splendid disco-
veries in paleontology. Until the
appearance of Dr. Mantell' s works
on the Geology of Sussex, the pe-
culiar relations of the sandstones
and clays of the interior of Kent,
Sussex, and Hampshire, were en-
tirely misunderstood. No one sup-
posed that these immense strata
were altogether of a peculiar type,
and interpolated amid the rest of
the marine formations, as a local
freshwater deposit. — Prof. Phillips.
Dr. Mantell observes that the
Wealden may be considered as
covering an area 200 miles in
length, from west to east, and 220
miles from north-west to south-east,
the total thickness averaging about
2000 feet. Of this series of deposits,
clays, or argillaceous sediments,

W E A

[461

W E K

with limestone almost wholly com-
posed of freshwater snail- shells,
occupy the uppermost place ; sand
and sandstones, with shales and
lignite, prevail in the middle;
while in the lowermost, argillaceous
beds, with shelly marbles or lime-
stones, again appear; and, buried
beneath the whole, is a petrified
forest, in which the trees are still
standing, and the vegetable mould
undisturbed. The organic remains
of the "Wealden consist of leaves,
stems, and branches of plants of a
tropical character ; bones of enor-
mous reptiles of extinct genera ; of
crocodiles, turtles, flying reptiles,
and birds ; fishes of several genera
and species, and shells of a fluvia-
tile character. The vegetable re-
mains belong, some of them, to
plants which appear to have held
an intermediate place between the
Equiseta and Palms, as the Clath-
raria ; while others approach to
arborescent ferns, the species being
very peculiar, and not known in
any other deposit, whether of
higher or inferior antiquity. For
a knowledge of that enormous rep-
tile, the Iguanodon, we are entirely
indebted to the indefatigable and
scientific researches of Dr. Man tell.
WEA'THERING. A term used to ex-
press the action of the atmosphere,
rain, &c., on the surface of rocks.
There is no rock, even the hardest,
that does not bear some marks of
what has been termed weathering.
The amount of surface-change, so
produced, is exceedingly variable,
depending much on local causes.
The tors of Dartmoor, Devon, may
be referred to as excellent examples
of the weathering of a hard rock.
The weathering of these tors is so
exceedingly slow, that the life of
man will scarcely enable him to
perceive a change; therefore the
period requisite to produce their
present appearances must have been
very considerable. Variations in

temperature much assist the chem-
ical decomposing power of the
atmosphere.

"WEDGE-SHAPED. In botany, applied
to leaves that are broad at the
summit and gradually taper toward
the base.

WEIGHT OP THE ATMOSPHERE. The
air is an elastic fluid resisting pres-
sure in every direction, and is sub-
ject to the law of gravitation. The
pressure of the atmosphere is cal-
culated to be about fitteen pounds
to every square inch, so that the
surface of the globe sustains a
weight of 11,449,000,000 hundreds
of millions of pounds.

WE'NLOCK FORMATION. The lower for-
mation of the upper Silurian rocks,
comprising the Wenlock limestone
and Wenlock shale.

WE'NLOCK LIMESTONE. The upper
subdivision of the Wenlock forma-
tion. The Wenlock limestone,
says Sir E. Murchison is in every
respect identical with the well
known rock of Dudley, and con-
tains the same organic remains.
The colour of the rock is usually
grey, but the crystalline varieties
are sometimes dark blue, and more
rarely pink, the mass being freckled
with veins and strings of white
crystallized carbonate of lime. The
simple minerals hitherto observed
in the Wenlock limestone of Shrop-
shire, consist of crystallized car-
bonate of lime in various forms,
sulphate of barytes, sulphurets of
iron, peroxide of manganese, crys-
tals of copper pyrites and bitumen.
As regards the organic remains
hitherto discovered, the most strik-
ing zoological feature consists in
the vast number of contained corals.
The most prevalent of these are
Heliopora pyriformis ; Catenipora
escharoides ; Stromatopora concen-
trica ; Pavosites gothlandica ; Cya-
thophyllum turbinatum; Limaria
clathrata, &c. Among the mollusks
and conchifers may be enumerated

WEN

[ 462 ]

WIN

Euomphalus discors, Euomphalus
funatus, and Euomphalus rugosus;
Productus euglyphus and Productus
depressus; Atrypa aspera and
Atrypa tenuistriata ; Terebratula
imbricata and Terebratula cuneata ;
Nerita, Haliotis, &c. Orthocerata
are also found. Trilobites are most
abundant, the prevailing species
being Asaphus caudatus and Caly-
mene Blumenbachii. Some other
species of trilobites appear to be
peculiar to the Wenlock formation,
as the Calymene variolaris, Caly-
mene macrophthalma ; Asaphus
Stokesii, and the genus Acidaspis,
so named by Sir R. Murchison.

WENLOCK SLATE. Called also Wen-
lock shale. An argillaceous, dark-
grey or liver-coloured shale, con-
stituting the lower member of the
Wenlock formation, and containing
nodules of sandstone. The Wen-
lock shale, or lower member of the
Wenlock formation, is characterized
by certain species of shells, the
most abundant of which are Pro-
ductus transversalis ; Spirifer car-
diospermiformis ; and Spirifer tra-
pezoidalis ; Terebratula breviostra,
Terebratula imbricata, and Tere-
bratula interplicata ; Asaphus lon-
gicaudatus ; and Orthoceras atten-
uatum." — Sir R. Murchison.

WE'BNE.RITE. A rare mineral of a
greenish grey, olive green, or,
sometimes, white colour, occurring
in eight- sided prisms, terminated
by four-sided summits, whose faces
form with the alternate lateral
plates, on which they stand, an
angle of about 121°. It is found
at Arendal in Norway, and in
Sweden and in Switzerland, and
named after Werner. It consists
of silex 45-5, alumine 33-5, lime
13-22, oxide of iron 5'75, oxide of
manganese V47.

WHEEL-SHAPED. In botany, a term
applied to a corolla of a salver-
shaped form, having scarcely any
tube.

WETHEEE'LLIA. The name given
by Mr. Bowerbank to a genus of
fossil fruits found in the London
clay. He says " it is perhaps the
most abundant of all the fruit
found in the Isle of Sheppey, and
is well known throughout the
island by the name of Coffee, to
which some of the sections of the
fruit, when separated from each
other, bear a very strong resem-
blance."

WHET SLATE. | The Novaculit®

WHET- STONE SLATE, j of Kir wan.
Por a description, see Hone.

WHI'NSTONE. A provincial term ap-
plied to some of the trap rocks.
In the western parts of Sussex,
says Dr. Mantell, layers of chert
or hornstone, provincially termed
whinstone prevail in the sand near
Petworth, &c. This stone is a
compact mass of quartz, but not
homogeneous, for it contains iron,
and perhaps some other substance.

WHITE-STONE. Pelspathic granite,
called by the French Eurite, and
by Werner Weiss-stein.

WHOKL. In conchology, a wreath,
volution, or turn of the spire of a
univalve; the axis of revolution is
termed the columella, and the turns
of the spiral are denominated
whorls.

2. In botany, a species of inflores-
cence, in which the flowers sur-
round the stem in the form of a
ring ; also applied to leaves, when
they arise in a circle round the
stem.

WING.

1. The limb of a bird or insect by
the aid of which it is able to fly.

2. In botany, a membranous appen-
dage to some seeds, serving to waft
them along in the air; applied
also to the two side petals of a
papilionaceous corolla.

WINGED. Having wings. In botany,
applied to stems, when the angles
are extended into leafy borders;

WIT

[463]

WOO

also to petioles having a leafy
border on each side.

WI'THAMITE. A mineral, so named
by Sir 1). Brewster, in honour of
its discoverer, H. Witham, Esq.
It occurs at Gleneo, in Argyleshire,
in minute translucent, brilliant
carmine red crystals, in form re-
sembling epidote. Specific gravity
= 3-1-3-3. Hardness == 6-0-6-5.
— Allan.

WI'THERITE. So named after Dr.
Withering, its discoverer. Carbo-
nate of Barytes. The Baryte car-
bonatee of Haiiy ; the Witherit of
Werner; the Barolite of Kirwan.
Witherite, or native carbonate of
barytes, is one of the rarer produc-
tions of the mineral kingdom. At
Anglesark, in the county of Lan-
caster, it is found in veins travers-
ing the independent coal formation,
and accompanied by blende, galena,
calamine, and heavy spar. It
occurs also in Shropshire, in the
lead mines, where it is met with
in irregular masses, weighing from
forty pounds to two or three hun-
dred weight, imbedded in heavy
spar. The name given to this sub-
stance by the miners is yellow spar,
not that this is its real colour by
day-light, but its transparency is
so considerable that if a lighted
candle be placed behind a mass of
it, the whole will glow with a yel-
lowish light, a circumstance by
which the miners distinguish it
from heavy spar. The colour of
witherite is white with the slightest
possible, if any, tinge of yellow;
its fracture is broad striated, ap-
proaching to straight foliated ; it is
for the most part massive. The
Anglesark witherite, according to
Klaproth, contains, besides carbo-
nate of Barytes, above two per
cent, of carbonate of strontites, and
a scarcely appreciable quantity of
oxide of copper. A specimen
analyzed by Mr. Aiken, gave, car-
bonate of barytes 96-3, carbonate

of strontites 1*1, sulphate of barytes
0'9, silex 0*5, alumine and oxide
of iron 0'25.

WOLF. (wolf, Germ.) The wolf
affords an excellent illustration of
the complete extinction of species.
Wolves were formerly exceedingly
numerous in Great Britain, and
were met with in Ireland even so
late as the beginning of the 18th
century. At the present day,
unless seen in a menagerie, or read
of as still existing in other count-
ries, and formerly in this, the
natives of these islands might be
perfectly unaware that the wolf
ever had any existence.

WO'LFEAM. The name given by
Werner to the ferruginous oxide of
tungsten.

WO'LLASTONITE. A mineral, thus
named in honour of Dr. Wollaston.
Prismatic augite.

WOOD-COAL. Another name for brown
coal.

WOOD-OPAL. Opalized wood. The
Holz-opal of Werner ; the Quartz
re*sinite xylo'ide of Haiiy : Ligni-
form opal of Kirwan. A variety
of opal, occurring in various vege-
table forms, and being in reality
opalized vegetable matter. Wood
changed by silicious infiltration, in
which the original structure is still
preserved, often in its minutest
parts, and the woody fibres appear
rather masked by its silicious in-
vestment than destroyed. Wood
opal is of various colours, white,
grey, brown, and black. In frac-
ture, lustre, and translucency, it
scarcely differs from semi-opal ; it
may be regarded as intermediate
between common opal and semi-
opal. Prof. Jameson relates that
many years ago, the trunk of a tree
penetrated with opal was found in
Hungary, which was so heavy that
eight oxen were required to draw
it. It is found in Hungary, the
Faroe Islands, and Van Diemen's
Land.

woo

[464 ]

X I P

WOOD-STONE. The Holstein of Wer-
ner ; Quartz agathe xylo'ide of
Haiiy ; Le bois petrifi e of Brochant.
Wood petrified with hornstone.
Prof. Jameson places wood- stone as
a subspecies of hornstone ; Prof.
Cleaveland terms it agatized wood,
and says this substance appears to
have been produced by the process,
commonly called the petrifaction
of wood. It is essentially composed
of silicious earth, which, it is
highly probable, has been gradually
deposited, as the vegetable matter
was decomposed and removed.
Both its form and texture indicate
its origin. Thus it presents, more
or less distinctly, the form of the
trunk, branches, roots, or knots,
which once belonged to the vege-
table. The colour of wood-stone
is generally grey, shaded with blue,
yellow, &c. The colours are often
with spots, sometimes striped.
Hardness nearly that of common
quartz. Specific gravity 2*67. It oc-
curs in sandstone or sandy loam, and
is capable of being highly polished.

WOOD-TIN. The Etain oxide concre-

tione* of Haiiy. The Kornishches
Zinnerz of Werner. A variety of
oxide of tin ; fibrous oxide of tin.
This has been hitherto found only
in Cornwall and Mexico. It occurs
in fragments which are generally
rounded. Its colours are light or
chesnut brown, reddish brown, and
yellowish grey. It is opaque ; of
a fibrous texture; easily broken.
Specific gravity from 6'4 to 6*7.
It is infusible before the blowpipe,
and irreducible. It consists of
oxide of tin 91 '0, oxide of iron 9.

WORTH SANDSTONE. So named from
its being fully developed at Worth,
near Crawley, in Sussex. A series
of white and yellow sands, consti-
tuting the lowermost member of
the Hastings beds. Its organic
remains are principally ferns and
arundinaceous plants.

WOE'THITE. The name assigned to
an earthy mineral, occurring in
boulders in Sweden, and Finland.
It is met with in foliated crystal-
line masses of a white colour;
transparent ; lustre vitreous ;
scratches quartz. — Allan.

X

XA'NTHITE. An earthy mineral, con-
sisting of a congeries of small
rounded grains, easily separable
and may be crushed by the nail.
Colour greyish or yellow. It has
been found only at Amity, in
Orange County, United States.

XI'PHIAS. (Wia?, from £/0o9, a
sword, Gr.) The sword-fish.

XI'PHODON. (Sword- tooth.) The name
assigned by Cuvier to a sub-genus
of Anoplotheria. In the xiphodon
the anterior molars are slender and
trenchant, and the posterior ones
below have, opposite the concavity
of each of their crescents, a point

which, in the course of wear, also
takes the form of a crescent, so that
then the crescents are double, as in
the ruminants. — Pidgeon. The
xiphodon has been hitherto found
fossil only, and in post-cretaceous
strata. It is a small and delicate,
long and slender limbed anoplo-
therian animal. A second species,
Xiphodon Geylensis, has been
added by M. Gervais to the type
species, Xiphodon Gracilis. The
existence of the Xiphodon is con-
sidered to have been limited to the
Eocene period.
XI'PHOID. (from |f/0o9; a sword, and

X I P

[465 ]

Y T T

a<$o<?, form.) Resembling a sword :
a term applied to the cartilage
placed at the lower extremity of
the sternum or breast-bone.

XIPHOS'URA. The seventh order of
the class Crustacea, comprising the
king-crab, or limulus, and the
extinct genera Halycina and Belli-
nurus.

XULINOSPBIONI'TES. The name given
to a genus of fossil fruits found in

the London clay. Mr. Bowerbank
describe them thus : " legumes
valveless, woody, two-seeded," and
observes " the pericarp of the fruits
of this genus unites, in a singular
manner, the characters of the
legume and the drupe."
XYLO'PHAGI. (from gv\ov, wood,
and 0a7etV, to eat, Gr.) A family of.
coleopterous insects, comprising
several genera.

YA'NOLITE. The name given by
Lametherie to the Axinite of Haiiy
and the Thummerstone of Kirwan.

YE'LLOW-QUARTZ. (The Quartz hyalin
Jaune of Haiiy.) A variety or
sub-species of quartz, of various
shades of yellow, and nearly trans-
parent. It has been also called
citrine and false or Bohemian topaz.
In Scotland it has obtained the
name of Cairn-gorm.

YE'NITE. So named from Jena.
Called also Lievrite. It is found
in the Isle of Elba and in Norway.
A mineral of a black or blackish-
green colour, occurring crystallized
and massive. It is opaque; scratches
glass; gives sparks with steel.
Specific gravity from 3§8 to 4,
Longitudinal fracture foliated ;
cross fracture conchoidal or uneven :
lustre resinous. Before the blow-
pipe it fuses into a dull, opaque,
black globule, strongly attracted
by the magnet. It consists of silex
30-0, lime 12-5, oxide of iron 57'5.

YU'CCITES. A genus of plants, thus
designated by Dr. Martins, and
which, he says, constitutes a series
allied to the palms, differing in

structure from most of the monoco-
tyledons, in having the stem
broadly expanded above by a more
or less perfect dichotomy.

Y'TTRIA. A name given by Ekeberg
to a new earth discovered by Gad-
olin, in 1797, in the quarry of
Yetterby, in Sweden. It has also
been named Gadolinite, after
Gadolin. The equivalent of Yttria,
according to Berzelius, is 40*2.

Y'TTRITJM. The name given by Eke-
berg to a metal forming the basis
of Yttria. In that mineral it is
combined with the oxides of iron
and manganese, and a small portion
of lime, and silica. "When separ-
ated from these substances, it has
the appearance of a fine white
powder, without either taste or
smell. It is infusible, and is inso-
luble in water. Its equivalent,
according to Berzelius, is 32-2.

YTTROTA'NTALITE. The name given
by Brochant to Ittrious oxide of
Columbium. Yttrotantalite, like
like Yttria, is found in the quarry
of Ytterby, in Sweden. It is of a
dark grey colour ; shining, metallic
lustre ; found in reniform masses.

2 o

Z A F

[ 466 ]

E C

ZA'FFEE. An impure oxide of cobalt,
obtained by roasting the ore of
cobalt, by which process the arsenic
and sulphur contained in the ore
are driven off. Zaffre melted with
silex and potash, and reduced to
powder, constitutes the article
known under the name of powder
blue. So intense is the blue
afforded by Zaffre, that one grain
will give a full blue to 240 grains
of glass.

ZA'MIA. A genus of the class Appen-
dix palmse, Dioecia, order Polyan-
dria, natural order of Palmse, Fili-
ces (Juss). Generic character:
Male, — calyx ; ament strobile-
shaped, ovate, obtuse ; scales hori-
zontal, pellate, obovate, very blunt,
one-flowered, thickened at the top,
permanent. Corolla none. Sta-
mina : filaments none. Anthers
subglobular, clustered, accumulated
in the lower surface of the scales,
sessile, two-valved, opening above
by a longitudinal cleft. Pollen,
farinaceous. Female, — calyx ;
ament strobile- shaped, larger, ovate,
imbricate; scales pedicelled, pellate,
angular, finally distant, permanent.
Corolla none. Pistil : germs two,
irregular, angular, inserted into the
margin under the pelta of the scales,
solitary on each side, nodding.
Style none. Stigma obtuse, ob-
scurely cloven at the side. Peri-
carp: " berries to each scale two
ovate, barked at the base, fleshy,
one-celled. Seed one in each berry,
ovate. Essential character: Male,
ament strobile-shaped, scales cov-
ered with pollen underneath.
Female, ament strobile-shaped,
with scales at each margin ; berry
solitary.
Fossil zamise have been disco-

vered in the coal formation, and in
the Wealden formation at Yaver-
land, on the south coast of the Isle
of Wight.

ZA'MITE. A fossil zamia. M. Ad.
Brongniart has referred the zamite,
or fossil zamia, to a new genus, to
which he has assigned the name of
Mantellia nidiformis.
ZECH-STEIN. | (The Magnesian Lime-
ZETCHS*EIN. j stone of English; Cal-
caire Alpen of French ; the Alpen-
kalkstein of German Geologists.
The name Zechstein was given to
this formation by Humboldt.) The
second member of the red sandstone
series, in the ascending order. The
zech-stein is a calcareous deposit,
or magnesian limestone, of a some-
what variable aspect ; it is fossili-
ferous, and in it, as far as observa-
tions have yet gone, are found,
for the first time, those shells known
by the name of Products; Spirifera
also now are found, for the first
time, in the descending series;
these and Productse both abound-
ing in the Carboniferous Limestone.
The organic character of the zech-
stein, as far as the researches of
geologists have hitherto gone, near-
ly approaches that of the carboni-
ferous group, a circumstance which
will greatly tend to add to the
difficulty of determining between
the zechstein and the carboniferous
limestone, when their geological
position cannot be ascertained with
certainty. Some geologists are of
opinion that the connection between
the two formations of red sandstone
and zech-stein is so intimate, that
the latter may be regarded as a
subordinate formation to the former.
The zech-stein lies immediately
under the new red sandstone and

Z E 0

[ 467 ]

Z E U

above the marl slate, or kupfer
sehiefer, of the magnesian lime-
stone formation. It is a deposit
not widely spread over the Euro-
pean area, and is principally known
in Germany and England. Some
authors comprise a series of depo-
sits, formerly known to the German
miners under a variety of terms,
under the name of zechstein, these
were the Asche, Stinkstein, Rauch-
wacke, Zechstein, and Kupferschie-
fer. The Magnesian Limestone of
England may be regarded as the
equivalent of the Zechstein of Ger-
many.

ZE'OLITE. (from £e'w, to swell or foam,
and \i'0os, a stone, Gr.) The Me-
sotype of Haiiy : Kouphon Spath
of Mohs.

1. Under this name, some miner-
alogists comprise eleven subgenera
of the mineral genus zeolite.

2. A translucent and, sometimes,
transparent mineral of a white,
yellow, or brownish- yellow colour,
exhibiting double refraction. Zeo-
lite is rendered electric by heat,
one summit of its prisms becoming
positive and the other negative;
the latter is usually that summit
which was connected with the
gangue. It is found in distinct
crystals, whose surfaces have a
strong lustre, slightly pearly ; and
in masses composed of several fas-
cicular groups of minute crystals;
and in each group the crystals or
fibres diverge, or even radiate, from
one point, and at the surface fre-
quently appear distinct from each
other, or exhibit pyramidal termi-
nations. Some zeolites phosphor-
esce by friction. Before the blow-
pipe, zeolite fuses with much ebul-
lition or intumescence into a whitish
spongy enamel, and it is from this
property that it has obtained its
name. When reduced to powder
and thrown into nitric acid, it is
converted into a jelly in the course
of a few hours. This property of

becoming gelatinous, as well as
that of becoming electric by heat,
sufficiently distinguish zeolite from
stilbite, analcime, chabasite, har-
motome, and prehnite. Zeolite
most frequently occurs in amygda-
loid, basalt, greenstone, and clink-
stone poryhyry. It is also found
in granite and gneiss.

ZE'KO. (zero, Fr. zero, It.) This
word is of Italian derivation, and
means a cipher or 0. The expres-
sion is used to denote a certain
point or mark on the thermometri-
cal scale. In the thermometers of
Celsius and Reaumur, zero is the
point at which water congeals. In
Wedgewood's pyrometer, zero cor-
responds with 1077° of Fahrenheit's
scale. The question has been pro-
pounded, "at what degree would a
thermometer stand (supposing the
thermometer capable of measuring so
low) were the" body to which it is
applied totally deprived of caloric ?
or what degree of the thermometer
corresponds to the real zero?" This
question does not appear to have
ever been satisfactorily answered.
Dr. Crawford placed the real zero
1268° below 0. Mr. Kirwan fixed
the real zero at 1048° below 0.
Lavoisier and La Place placed the
real sero at 2736° and 5803°
below 0.

ZE'THUS. The name given by Pander
to a genus of trilobites, added by
himself to those previously des-
cribed.

ZE'TJS. (zeus, Lat.) A genus of fishes
of the thoracic order, having the
head compressed and sloping, the
upper lip arched, the tongue subu-
lated, the body compressed, thin,
and shining, and the rays of the
first dorsal fin ending in filaments.
In Dr. Mantell's Geology of the
South-East of England, a species
of Zeus, found in the chalk, the
Zeus Lewesiensis, is beautifully
figured. This ichthyolite is from
six to eight inches long, and its

Z I

[468]

Z 0 D

width is nearly equal to the length
of the body. — Dr. Maniell.

ZINC. ] (sink, Germ.) A metal of a

ZINK. ) bluish-white colour, with a
fine granular fracture. Zinc was
not obtained in its metallic form
till the sixteenth century, though
its ores were known to the ancients,
and used by them in the formation
of their brass or bronze. It does
not occur native ; its most abundant
ore is the sulphuret, called Blende,
common in most veins which con-
tain sulphurets of iron, lead, copper,
&c. in every country. The structure
of zinc is foliated. As regards its
hardness, it may be easily cut with
the knife. Specific gravity from
6-9 to 7-2. It is malleable, but its
malleability is greatly increased by
heating it to a temperature of 300
Fahrenheit. By exposure to the
air it tarnishes and loses its lustre,
but it is but little oxidated. Uni-
ted with copper it forms brass. The
ores of zine are few. Its presence
may be determined by roasting the
ore, and then fusing it by the
blow-pipe on charcoal with filings
of pure copper. If zinc be present,
the copper will be converted into
brass. The ore called calamine is
a carbonate of zinc.

ZI'PBTTJS. The name assigned by
Cuvier to a genus of cetacea; it
contains three species, and appro-
ximates lo the cachalots and hy-
peroodontes. The head differs from
that of the hyperoodon, in the
maxillary bones not forming verti-
cal partitions on the sides of the
muzzle, and in the partition behind
the nostrils not only rising verti-
cally, but also curving, so as to
form a kind of half cupola over
these cavities. — Pidgeon.

ZI'RCON. (By some the word zircon
is deemed of Indian origin, others
derive it from the French word
jargon, esp&ce de diamantjaune.J A
mineral occurring in rounded grains
or fragments, or in regular crystals.

The primitive crystal of zircon is,
according to Haiiy, an obtuse octo-
hedron; the common base of the
pyramids is square. The measure-
ments, as afforded by the reflecting
goniometer, are 84° 20' by 95°
40'. It is harder than quartz, and
possesses double refraction in a
high degree. It is transparent, or
sometimes only translucent. Spe-
cific gravity from 4-3 to 4*7 Before
the blow-pipe it is infusible, but
loses its colour. It may be dis-
tinguished from garnet, idocrase,
staurotide, &c., by its infusibility,
specific gravity, and strong double
refraction. There are two varieties
of zircon, called zircon jargon and
zircon hyacinth. Zircon jargon
consists of zirconia 69, silica 26'5,
oxide of iron 0'5. Zircon hyacinth
of zirconia 70, silica 25, oxide of
iron 0'5 Some mineralogists divide
zircon into three subspecies, name-
ly, zirconite, hyacinth, and jargon.
The finest specimens are brought
from the island of Ceylon. It
occurs in primary and transition
rocks, but is usually obtained from
the sand of rivers.

ZIRCO'NIA. An earth, when pure,
white and tasteless, supposed to be
a compound of zirconium, its me-
tallic basis, and oxygen. An oxide
of zirconium.

ZIBCO'NITE. A subspecies of zircon,
consisting, according to the analy-
sis of Klaproth, of zirconia 69,
silica 26-5, oxide of iron 0'5* It
occurs in reddish-brown and nearly
opaque prismatic crystals. Itishard-
er than quartz, but softer than dia-
mond. Sp. gr. from 4'5 to 4*7.

ZIECO'NIUM. The metallic base of
zircon.

ZOANTHA'RIA The third order of the
class actinozoa, comprising six-star-
red corals, sea-anemone, beroe, &c.

ZO'DIAC. (zodiaque, Fr. zddiaco, It.
zodiacus, Lat. gwdicuco?, Gr.) A
broad circle or region in the hea-
vens, remarkable, not from any thisg

Z 0 D

peculiar in its own composition,
but from its being the area within
which the apparent motion of the
sun, moon, and all the great pla-
nets are confined. The centre of
the zodiac is the ecliptic, which is
inclined to the equinoctial at an
angle of about 23° 28', intersecting
it at two opposite points, called
the equinoctial points. The zodiac
extends 9° on either side of the
ecliptic.

ZODI'ACAL. Pertaining to the zodiac,
as the zodiacal constellations, &c.

ZOI'SITE. | A mineral, thus named from

ZOI'ZITE. ) Baron Yon Zois, its dis-
coverer. A variety of Epidote, of
a grey, brown, or yellowish colour.
Prof. Jameson constitutes zoisite a
species, which he divides into two
subspecies, namely, common zoisite
and friable zoisite: he adds, "it
would probably be an improvement
to arrange zoisite as a subspecies of
epidote."

ZOO'LOGY. (from %£ov, an animal,
and XoV/o?, discourse, Gr.) That
branch of natural history which
treats of animals, their habits,
structure, classification, &c.

ZOO'LOGY FOSSIL. That division of
zoology which treats of fossil ani-
mals. The examination of the
fossil remains of a former state of
creation has demonstrated the ex-
istence of animals far surpassing in
magnitude those now living, and
brought to light many forms of
being which have nothing anala-
gous to them at present, and many
others which afford interesting con-
necting links between existing ge-
nera.

ZOO'PHAGA. (from £woi>, an animal,
and 0a<yeti/, to eat, Gr.) A tribe
of animals which attack and devour
living animals. The animals of this
tribe have three kinds of teeth,
namely, cutting teeth, canine teeth,
and grinders; their paws are armed
with claws ; their muzzle is often
set with whiskers, usually called

[_ 469 ] ZOO

smellers; their mammary organs
are dispersed ; their intestines are
less voluminous than those of her-
bivorous animals.

ZOO'PHAGOTJS. Attacking and devour-
ing living animals.

ZO'OPHYTE. (gwofora, from £oW,
and 0vw, Gr. qua media sunt na-
tura inter animalia et plantas.)
Animal plants, corals, sponges, and
other aquatic animals which have
obtained the name from an opinion
formerly entertained that they were
intermediate between animals and
vegetables. In consequence of their
aggregation, which produces trunks
and expansions of various forms,
together with the simple nature of
their organization, and the radia-
ting disposition of their organs,
resembling the petals of flowers,
these animals owe their name of
zoophytes or animal plants. But
possessing the power of voluntary
motion, enjoying the sense of touch,
feeding on matters which they have
swallowed, and digesting these in
an internal cavity, they must, in
every point of view, be considered
to be animals. Many of the lowest
zoophytes, which have no digestive
sac, and no polypi, absorb their
whole nourishment by the surface
of their body, or by the parieties
of canals which traverse their in-
interior. Zoophytes present to the
physiologist the simplest indepen-
dent structures compatible with the
existence of animal life; the means
of their propagation and increase
are the first of a series of facts on
which a theory of generation must
rise. Zoophytes are either free in
the sea, or are attached for life
after a very early period of growth.
"We may compare," says Lyell,
" the operation of zoophytes in the
ocean to the effects produced on a
smaller scale upon the land by the
plants which generate peat. In
corals, the more durable materials
of the generation that has passed

zoo

[470]

Z U It

away serve as the foundation on
which living 'animals are continuing
to rear a similar structure.

ZOOPHYTO'LOGY. (from ^wo^vra, a
zoophyte, and Xo'fyo?, discourse,
Gr.) That branch of natural his-
tory which treats of the structure,
habits, &c. of zoophytes.

ZOO'TOMY. (from %&ov, an animal,
and -refiveiv, to cut.) A term em-
ployed to express the knowledge
acquired by dissecting the bodies of
animals. This science makes us
acquainted with their organization,
or with the structure and form of
all their internal parts and organs.
It points out the connections which
subsist between the different parts
of the animal machine, by which
they are all enabled to co-operate
towards the same great objects —
the preservation of the individual,
and the continuance of the race.

It examines the changes which the
organs undergo at different periods
of life. It traces the modification
of form and structure presented by
the different organs and parts of
the machine, in all the inferior
tribes of animals, by which the
whole organization of the species
is always admirably adapted to the
circumstances in which they are
placed. — Prof. Grant.

ZO'STEEA. A genus of plants growing
by the sea-side, belonging to the
class gynandria, order polyandria.

ZOSTEKI'TES. Fossil plants of the genus
zostera. Pout species have been
determined by Ad. Brongniart,
namely, Z. bellovisana, Z. caulini-
sefolia, Z. elongata, and Z. lineata:
these have all been found in the
chalk of the Isle d'Aix.

ZTJ'BLITE. The name given to a Ve-
suvian mineral.

E Y D E 1

JAMES BEIDDON, PRINTER,
CKOSS STREET.

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A DICTIONARY

DOMESTIC "MEDICINE

AND

HOUSEHOLD SURGERY

BY

SPENCER THOMSON, M. D. EDIN., F. R. C. S.

WITH ONE HUNDRED AND FIFTY ILLUSTRATIONS

From the Author's Prefatory Address.

WITHOUT entering upon that difficult ground which correct professional
knowledge, and educated judgment, can alone permit to be safely trodden,
there is a wide and extensive field for exertion, and for usefulness, open to
the unprofessional, in the kindly offices of a true Domestic Medicine; the
timely help and solace of a simple Household Surgery, or better still, in the
watchful care, more generally known as " Sanitary Precaution," which tends
rather to preserve health than to cure disease, "the touch of a gentle hand'1
will not be less gentle, because guided by knowledge, nor will the safe domes-
tic remedies be less anxiously or carefully administered. Life may be saved,
suffering may always be alleviated. Even to the resident in the midst of
civilization, the ** knowledge is power" to do good; to the settler and the
emigrant, it is invaluable.

I know well what is said by a few, about injuring the medical profession,
by making the public their own doctors. Nothing will be so likely to make
" long cases " as for the public to attempt any such folly ; but people of
moderate means — who, as far as medical attendance is concerned, are worse
off than the pauper — will not call in and fee their medical adviser for every
slight matter, and in the absence of a little knowledge will have recourse to
the prescribing druggist, or to the patent quackery which flourishes upon
ignorance, and upon the mystery with which some would invest their calling.
And not patent quackery alone, but professional quackery also, is less likely to
find footing under the roof of the intelligent man, who, to common sense and
judgment, adds a little knowledge of the whys and wherefores of the treat-
ment of himself and family. Against that knowledge which might aid a
sufferer from accident, or in the emergency of sudden illness, no humane
man could offer or receive an objection.

NOTICES OP THE PRESS: —

The London Journal of Medicine says, — "The best and safest book on
Domestic Medicine and Household Surgery which has yet appeared."

The Dublin Journal of Medical Science says, — "Dr. Thomson has fully suc-
ceeded in conveying to the public a vast amount of useful professional know-
ledge."

The Christian Witness says, — "The best production of the kind we possess."

The Medical Times and Gazette says, — "The amount of useful knowledge
conveyed in this work is surprising."

CHARLES GRIFFIN & COMPANY, LONDON.

THE

BOOK OF DATES

A Treasury of Universal Reference

Comprising the Principal Events of all Ages, from the Earliest Periods
to the End of 1861, arranged Chronologically and Alphabetically, with
Index of Names, in one large volume, post 8vo, cloth gilt, antique
bevelled, price 7s. 6d.

From the Preface.

THE great objects in view in this work are to present simultaneously
to the eye of the reader the chief contemporaneous events in the
history of the world, divested, as much as possible, of reflection and
inference, yet clearly showing the tendency and progress of each
nation in connection with all ; to give a full and fair record of facts,
so arranged that the widening circle of their effects might be readily
traced by a thinking mind ; to furnish the well-read historian with
a remembrancer, and the unread student with a book of reference,
wherein he could, at a moment's notice, ascertain the events amid
which an individual life was passed — the circumstances which ren-
dered a particular era remarkable — the date of any important or
curious fact in War, Statesmanship, Science, Art, Religious develop-
ment, &c., — wherein, too, he could trace their antecedents and se-
quences, though his memory might afford but a slight clue to the
discovery of those precise periods, acts, or dates.

The work consists of two parts: in the first of which are exhibited,
in synchronistic order, the principal events that have occurred in the
several countries of the world ; in the second is given an alphabetical
arrangement of all the curious or important facts of history, so clas-
sified that, with a very small expenditure of time and care, the work
may be used as a comprehensive guide to universal history.

The publishers have great confidence that they are giving to the
scholar a vade mecum of considerable value — to the man of business
a "ready reckoner" in history — to the general reader a treasury of
facts — and to the man of letters a complete book of reference.

From the Spectator. — " A storehouse of facts and dates."

From the Literary Gazette.—11 Admirably adapted for a work of reference

CHARLES GRIFFIN & COMPANY, LONDON.

THE

HAND-BOOK OF BIOGRAPHY

Biographies of the most Distinguished Persons of all Times

A Complete Series of Original Memoirs of the most Remarkable Indi-
viduals of all Times and Nations, by Alison, Brewster, Burton, Creasy,
Eadie, Knight, Nichol, Spalding, Wornum, and other Contributors.
Third editiqn, revised and enlarged, with 100 engraved portraits, and
150 illustrations of Birthplaces, &c., in one thick volume, 8vo, half-
bound B/oxburghe style, gilt top, price 10s. 6d.

The Critic says, — " Messrs. GRIFFIN & Co.'s * Hand-book of Biography ' is, we
believe, the most carefully compiled and satisfactory of this class of books which
have of late years issued from the press. It differs from all popular biographical
dictionaries in this — that the principal lives of each class of remarkable men have
been entrusted to practical writers, who have cultivated the corresponding depart-
ments of learning. The result is, not only an eminently trustworthy, but an
unusually interesting volume. It extends to nearly 900 pages, and has some 150
or more illustrations of birthplaces, monuments, and other memorials of departed
greatness, and is a wonderful instance of cheapness, completeness, and excellence."

The Art Journal says, — "The 'Hand-book of Biography' now before us is in
many respects a remarkable book. The best authorities have been chosen, and the
most eminent of our living writers in art, science, and literature, have been secured
to write these biographies. The names of Alison, of Brewster, of Nichol, with
numerous others of equal standing in the walks of history and science, are a
sufficient guarantee for the excellency of their biographies."

The Spectator says, — " This work differs from all single volumes of biography
in several remarkable features. The great number of subjects which it contains,
the variety, and indeed, the celebrity of the writers engaged, and the original
character imparted to the larger notices. The first, and for the purposes of reference
the most useful feature, is the number of persons noticed ; the men engaged on the
biographies are numerous and respectable, as may be seen from the enumeration on
the title, and each writer takes that class of lives with which his studies have made
him most familiar: Alison and Creasy, for example, undertake naval and military
men."

CHARLES GRIFFIN & COMPANY, LONDON.

Second Edition, in crown Svo, price 7s. 6e?., clot ft.

PROFESSOR CRAIK'S

MANUAL OF ENGLISH LITERATURE

THE HISTORY OF THE ENGLISH LANGUAGE
FROM THE NORMAN CONQUEST.

iiumeroug Specimen*.

CONTENTS :

Introduction — The Languages of Mo-
dern Europe — Original English (Saxon
or Anglo-Saxon) — Second English (Semi-
Saxon) — Third English (Mixed or Com-
pound English) — Chaucer, Spenser,
Shakespeare, &c., &c. — Middle and Lat-
ter Part of the Seventeenth Century;
Milton, Butler, Dryden, &c.— The Cen-

and the French Revolution : Swift,
Pope, Addison, Defoe, Goldsmith, John-
son, &c., &c.— The Latter Part of the
Eighteenth Century; Cowper, Burns,
&c. — The Nineteenth Century ; Words-
worth, Scott, Shelley, Byron, Crabbe,
&c., &c. — Literature of the Present
Day ; Browning, Tennyson, Hood, &c.

tury between the English Revolution

In this volume, and in the larger work of which it is an abridgment, an
attempt has been made to interweave with the history of our national Litera-
ture such an exposition of the revolutions and more gradual changes which
the Language has undergone as may suffice to present at least a correct general
view of the subject. It is shown that the English Language has assumed
successively only three distinct constitutions or forms ; and while each of them
is precisely defined both in the principle of its structure and in its limits as
to time, the simplest explanation is given of the causes which appear to have
produced the conversion of the first into the second and of the second into
the third.

In the survey that is taken of our Literature, it is believed that no writer
of any considerable note has been passed over, and as full accounts have been
given as the space at command would permit of all those of the highest rank,
and of their lives as well of their works, from Chaucer down to our own day.
Many more names, indeed, have been introduced than can, on the most liberal
construction, be held to belong to what is properly to be called the Literature
of the language ; but much necessarily enters into the history of every thing
which makes no part of the thing itself. All care has been taken throughout
to be accurate in the important point of dates. Nor in the critical apprecia-
tion of the authors that come under review will there be found, it is hoped,
any want of a sufficiently catholic spirit. Finally, large extracts have been
given from many of our great writers both in verse and in prose ; and here
every possible aid has been contributed by glossarial foot-notes to the easy
understanding of all obsolete or dialectic words and forms.

The Spectator says, — " The present volume is particularly adapted for the use of
Students going up to competitive examinations. Numerous illustrations of the
progress and development of the English Language are introduced, beginning with
King Canute and ending with Thomas Hood."

The Saturday Review says, — " Professor Craik is always clear and straightforward,
and deals not in theories but in facts ; all that he says is sound and practical and
eminently distinguished by good sense. We have philological books treating of our
earliest Literature, and we have critical books treating of our latest Literature, but
we do not know of any book which, like the present, embraces both."

CHARLES GRIFFIN & COMPANY, LONDON.

*>

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