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Pillished by A.Tilloch, Care Street, Fuly 1803

THE

PHILOSOPHICAL MAGAZINE:
COMPREHENDING
THE VARIOUS BRANCHES OF SCIENCE,
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BY ALEXANDER TILLOCH,

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CONTENTS

OF THE

SEVENTEENTH VOLUME.

tT. ON the Modifications of Clouds, and on the Principles
of their Production, Suspension, and Destruction; being
the Substance of an Essay read before the Askesian Society
in the Session 1802-3. By Luxn Howarp, Esq. Page 5
1I. Account of the Kookies or Lunctas: written by Jou
Macrae, Esq. and communicated to the Asiatic Society

by J. s HARRINGTON PESG! EL SS 1k
Il. An Essay on the Fecula of Green Plants. By Pro-
PpCseON AION Nils Oh aa Maislecaaly aiz'sl Wagan a DOR 22

IV. Account of a “Journes y to the Summit of the Peak of
Teneriffe: in a Letter from L. Corpier, Engineer of
Mines, to C. DEVILLIERS, junior..... Ad hath: ORS 3h

V. On Mr. ArtHur Wootr’s improved Apparatus, ap-
plicable to Steam Engines and other Purposes of Art and
Manufacture : including a Description of two Boilers now
erecting at Messrs. Mrvx’s Br CUTE? WM DEOL 40

VI. On the Motion of Bodies affected by Friction. By
the Rev. Samuet Vince, A.M. of Cambridge .... 47

VII. Observations on the Process of Tanning. By Hum-
pHrEY Davy, Esq., Professor of Chemistry in the. Royal
Prsertiemaesl ys ABB I Ee. Wo OPO RII IA. ok 58

VU. An Account of some Experiments and Observations
on the constituent Parts of certain astringent Vegetables ;
and on their Operation in Tanning. By Humpurey
Davy, Esq. Professor of Chemistry y in the Royal: ae
OPTRA AR: chs OD AFCO LE I

IX. Extract from - the third Volume of the ‘Anal; Ses o
Rk MiuwENOTH oo PA eRe FOI es OA. 76

X. Analysis of Ambergris. By BovurLton-LAGRANGE 88

XI Proceedings of Learned and, Economical Societies .. 92

XII. Intelligence and Miscellaneous Articles .......... g4

XII. Essay on the Franklinian Theory of Electricity. By
Samurt Woops, Esq. Read before the Askesian Society

AMINE Besson BOWS. asc cciccevd desde gee cis vs 97
XIV. On the Motion of Bodies affected by Friction. By the
Rev. SAMUEL VINCE, A. M. of Cambridge. ...... 113

XV. Copy of a Letter to the Rev. SAMUEL Vincr, Plumian
Professor of Astronomy, 8c. &§c., Cambridge, from
Joun Soutnern, Engineer, dated Birmingham, Janu-
ary 97 LEO RAI... Pieters GOR). He dO
Vou. XVII. No. 68. a XVI. On

CONTENTS.

XVI. On the Bite of a Snake cured by Volatile Alkali. By
DXA Waiarde SAY 5 IVER. Navcis declare + «e's aaj Page \25
XVII. Letter to Dr. Ramsay, in consequence of his Ob-
servations on the Bite of a Snake, cured by Volatile Al-

kali.’ By Bensamin Barron, M-D. .' . t 128
XVIII, Analysis of Ambergris, By Bourtton-LAGRANGE

131

XIX. Observations on the Employment of Platina in Porce-
lain Painting. By Professor Kuarrorny, of Berlin: 135
XX. Advantageous Method of preparing Red Oxide of
Quicksilver... By. J.W.C.\ FISCHER o. 6... ess 44 139
XXII. 4 Memoir concerning several indigenous Plants, which
may serve as a Substitute for Oak Bark, and for certain
foreign Articles in the Tanning of Leather... .... 140
AAIT. Process for Dyeing Nankcen Colour. By Mr. RicHARD
PMN Ons dibate davsasc'sly- yh fue xtc: aie ee 149

Fo “\os eanagi'd wlio uun- eandae(al nenat? -otéabtais 156
XXV. Description of a New, Safety-Piston for ,Papin’s
Digester, with the Application of it to the, Boilers of
Stcam-Engines, and also of an Apparatus for regulating
the Heat of Furnaces, By A. N. Ennicrantz, Knight
of the Swedish Order of the Polar Star, and Member of

several. Academies and Learned Societies... 64. s+ 6. 162
AXVI. Description of Mr. Anraur Woour’s. Sleam-
FHA wi) «wan + etaioe Wire e* einod “ky Jarman “athe 2 4 6¢
XXVII.. Deseriptian of a Portable Chamber Blast-Furnace.
By Go RAAIKIN, deiguy' Ss oa aaiiweAd edt -no doqhOG
XXVIIL. On the Preparation of the Fulminating Mercury
of Mr. Howann, ly Mr. A. S. BuRKITT .... oa 169

XXIX. Tenth Communication,from Dr. THORNTON’. 17%
XXX. Mr. Crose’s Communication to the Board of Agri-
Clbien > x. A kod WA « . inarcaden oe ieee 278
XXXI. Proceedings of Learned Societies... 4.04 «04+ 186
XXXIT. Intelligence and Miscellaneous Articles \.....188
AXNXUT, On Gems. By WH, Pepys, jun. Esq..P. RoI
Member of the Askesian Society. Read in Session
EO a. 5 fa war cays Ya aera es (al ve ah ee eee aE Gear, td 193
KXXILV, Of the general Relation between the Specific Gra=
aities qnd the Strengths and Values of Spirituous Liquors,
and the Circumstances by which the former are influenced
204

XAXY.On the Preparation of Indian Ink ; presenting an
easy and expeditious Method of providing a Substitute

| 2 possessing

CONTENTS.

possessing all its valuable Properties. By THomas Gitt,
ESET eB cieERE e athe cee ace. an ayo ed SERENE Page 210
XXXVI. An Account of some Experiments and Observa-
tions on the constituent Parts of certain astringent Vege-
tables ; and on their Operation in Tanning. By Hum-
pHrey Davy, Esq. Professor of Chemistry in the Royal

STAR TASH OO eA LM PENT aD irk SER IR ES 212
XXXVI. Of the Herring Fishery. Translated from the
French of M. Dunamen and others .....-..4..44- 218
XXXVIII. Lnproved Method of preparing Black Oxide of
Mercury... By M. Scuuuze, of Kiel... oc .0.s5-- 225
XXXIX. On the Stones said to have fallen from the At-
_, mosphere.» By J. DELALANDE(S. «0 dees eee s 83 298
XL. Extracts ae the Third Volume of the Analyses of
MM. KiLApROTH ..... rhino MDI Se MR? PPA nat RRR | 230

XLI. Examination of the Red coloured Water of a Lake near
Lubotin, in South Prussia. By Professor KLaPKorn 243
XLU. Explanation of the Inscription on a Brick from the
Site of antient Babylon. By the Rev. Samury HEn-
PGBs Mpa UP, ee an hs US Sete eats ate at RAE 250
XLUI. Eleventh Communication from Dr. THORNTON 254
XLIV. A Contribution towards the assaying of Coins. By
hE CSOR MD DEROTI A ceil AY An wager AEC Oy a 1258
XLV. On Cinis; a Kind of Alkaline. Earth formed during
the Incineration of Wood, not yet noticed by Chemists in
their Nomenclature. Addressed to GrorGE Pranson, ©
M.D. F.R.S. &c. by Samus, L, Mircsirt, M.D.
Member of Congress, &c. in a Letter, dated New York,
September 20, 1803, and communicated to Mr. TinL0cH
at the particular request of the Author .......2..+.. 267
XLVI. Account of a Shower of Stones; in a Letter from
the Prefect of the Department of Vaucleuse to the French
Minister of the Interior, dated November 10, 1803 ..271
XLVI. An improved Method of heating Boilers ; being an
Account of the Way in which the Fire is applied to one of
the large Boilers in Messrs. Meux’s Brewery ...... 5275
ALVUI. Account of the Metcor scen on the Evening of
Sunday, November. 13th. 1803; wilh some Observations
on the best Means of ascertaining the Altitude, Bearing,
Jagnitude, Distance, and Velocity of such Phenomena.

Oey PoP WAMINGER 66 0 ee co ka ye os ea 279
XLIX, Account of New Publications .........0..%- 284
L.» Proceedings of Learned and Economical Societies . . 285
LI. Intelligence.and Miscellaneous Articles ........ : 286
LI. Chemical Examination of an antient Speculum. By

Professor Kuarrotu, of Berlin ..........0.6005 289

LIL. An Account of some Experiments and Observations
on

CONTENTS.
on the constituent Parts of certain astringent Vegetal les ;
‘and on their Operation in Tawrting. ° By Huweunry
Davy, Esq., Professor of Chemistry in the Royal Tir-
stitution’ ..... 1 eT BE Sadi rhea eal a Page 295
LIV.’ Letter from J. Hume, Esq. on the Formation of
Nitrous Ether, by Means of Nitrate of Mercury, and on
ee Discoveries supposed to be modern .......« ‘np OD
LV. A Method of affording Relief to Persons injured ty
Lightning. Communicated in a Letter “from Mr. Isatan
© Gripent to the Rev. Mr. STECLE .. 0... 6.3... 306
LVI. Extracts from the Third Folame of the Analy yses va
AER EREMOTE cs Soon) DE ZAC ONC, SUE AD See
LVI. Analysis of the Human Teeth. By W: Bi. Bai.
juny Esq., P.R.I., Meniber of the Askesian and British
Mineralogical Societies AEB ies seen cra ter 313
EVI. On Sharks. By Witiram Taruam, Esq. . - 317
LEX. On Vegetation; extracted from C. FIASSENFR ATZ’S
Paper on that Sulject.. By G. J. Wricut, Esq... 318
EX. Observations on the Use of STAHL’s dlkalived Daiite of

Tron im Calico Printing. By J. M. Hausman ..... 323
EXI. On an npr ovement in the Form of Spectacle Glasses,
By We. Hypt Worrastox, M.D. FLRLS.. ..".' 327

LXIE. Of the general Relation letween the Specific Gravi-
ties and the Strengths and Values of Spirituous Liquors;
and the Circumstances by y whieh’ the former are influenced

329

EXIT. Extract of a Memoir read in the French National
fistitute, on the Strength of the Flax of New Zealand,
_ compared with that of the Filaments of the Aloe, of Hemp,

Flax, and Silk: By C. LaBicLARDIERE '... 1.22. 341,
EXIV.. Sketch of a Geological Delineuticn of South Ame~
rica. By F. A, Von Humpoupr........... pinoy 3 44

LY. Description of Mr, Ricuarp Knicut’s Apparatus
Sor preparing Fluoric Acid, and for Etching one Glass

ao7

EXVI. Description of the Vulture of Pondicherry. By
BRP Datre? .'F))? | SIA SEO SO ee 359
EXVHE. Twelfth Communication from Dr: THORNTON, on
Prenmatie’ Veticine 2500 VO Ge 890 Shy M66
LXVEI. Notices respe cling New Publicttions and the Fine
LWAS Er ostste tc beébeacen eee ort Ss ay tspe ieee '.. 364
LXIX. Proceedings of Tiss ned and Beowpiiiel ‘Societies :
row hg ag

LXX. Intelligence and- Miscellaneous Articles 00. oe. 374

70 [THE PUBLIC.

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and render it still more worthy of protection,

THE

THE

PHILOSOPHICAL MAGAZINE.

I. On the Modifications of Clouds, and on the Principles
of their Production, Suspension, and Destruction; being
the Substance of an Essay read before the Askesian Society
in the Session 1802-3. By Luke Howarp, Esq.

[Continued from vol. xvi. p. 357. ]
Of the Formation of the Cirrus.

i. must have been owing entirely to the want of distinc-
tive characters for clouds, and the consequent neglect of
observing their changes, that the nature of this modification
more especially has not engaged the attention of electri-
cians, Theattraction of aggregation operating on solid par-
ticles diffused in fluids does indeed produce a great variety
of ramifications in the process of crystallization: but these
are either uniform in each substance, or haye a limited
number of changes; and in no instance do we see the same
substance separating from the same medium, and, uncon-
fined in its movements, rival the numerous metamorphoses
of the cirrus.

The great elevation of these clouds in their ordinary mode
of appearance has been ascertained both by geometrical ob-
servations * and by viewing them from the summits of the
highest mountains, when they appear as if. seen from the
plain. A more easy and not less convincing proof may be
had by noting the time during which they continue to re-
flect the different coloured rays after sunset, which they do
incomparably longer than any others. The same configura-
tion of cirrus has been observed in the same quarter of the
sky for two successive days, during which a smart breeze
from the opposite quarter prevailed below.

it is therefore probable that this modification collects its
water in a comparatively calm region, which is sometimes
incumbent on the current next the earth, and almost out of
the reach of its daily variations in temperature and quantity

* «« The small white sireaks of condensed vapour which appear on
the face of the sky in serene weather I have, by several careful obser-
vations, found to be from three to five miles above the earth’s surface.”

pl aellil
Vor. XVIT. No. 65. A3 of
October 1803.

6 On the Modifications of Clouds, and

of vapour; but at other times is interposed between the
latter and a supervening current from another climate, in
which case it may be affected by both currents.

The cumulus has been just now considered as an insu-
lated body, consisting of perfectly moveable parts which
accommodate themselves to the state of redaining electricity,
We shall attempt to explain the nature of the cirrus by
comparing it to those imperfect conductors, which being
interposed between electrics and conductors, or between the
latter in different states, serve to restore by degrees the equi-
librium of the electric fluid.

If a lock of hair be properly fixed on the prime conductor
and electrified plus, the hairs will be separately extended at
as great a distance from each other as possible ; in which
gtate they will continue some time. The reason appears to
be, that the contiguous air is then minus ; and consequently
these two moveable substances put themselves into the state
most favourable to a communication which is but slowly
effected between bad conductors.

The same appearances will take place if the lock be elec-
trified minus, the contiguous air being plus; and in each
case the hairs will move from a body similarly electrified
and brought near them, and towards one contrariwise elec-
trified, &c. Moreover, if we could insulate such a charged
lock in the midst of a perfectly tranquil atmosphere of
sufficient extent, in which particles of conducting matter
were suspended, the latter would be attracted by it so long

. ‘ 7]
as the charge continued ; after which they would be at large

as before.

Dry air being an electric, and moist air but an indifferent
conductor, it is reasonable to suppose that an immediate
communication of electricity between masses of air differ-
ently charged can scarcely happen to any great extent, ex-"
cept by the intimate mixture of such masses ; an occurrence
which may possibly result in some such cases, and occasion
strong winds and commotions in the atmosphere. If we
consider how frequently, and to what an extent, the elee-
tricity of the air is disturbed (as appears from numerous
experiments) by evaporation, by the formation and pas-
sage of clouds, by elevation or depression of temperature,
(by friction upon surfaces of ice?) it seems probable that
the particles of water floating in a calm space may be fre-
quently converted into conductors, by which the equilibrium
is in part restored after such disturbance.

Viewing the cirrus in this light, it becomes important for
those who are well yersed in electricity to study its appear-

: . ances,

their Production, Suspension, and Destruction. 7

ances, and compare them with the changes that ensue in
the atmosphere. A number of observations, made hitherta
chiefly in one place, and without system or aid from con-
current ones in other places, haye furnished the preceding
data (see vol. xvi. p. 100), which may serve as hints for fu-
ture investigation.

At present we can only conjecture that the local detached
cirri which ramify in all directions are collecting particles
of water from the surrounding space, and at the same time
equalizing their own electricity with that of the air or va-
our.
: That when numerous oblique short tufts appear, they are
conducting between the air above and that below them.

That a decided direction of the extremities of pendent
or erected cirri from the mass they join towards any quar-
ter, is occasioned by the different electricity of a current of
air which is pressing upon the space they are contained in
from thence. This is the most important point to attend
to, as these ¢ails sometimes veer half round the compass
in the course of a few hours; and many observations have
confirmed the fact that they point towards the coming wind,
and are larger and lower as this is about to be stronger.

Lastly, that cirri in parallel lines stretching from horizon
to horizon denote a communication of electricity carried
on through these clouds over the place of observation; the
two predisposing masses of atmosphere being very distant,
and the intermediate lower atmosphere not in a state to
conduct it. It is at least a circumstance well deserving in-
quiry, by what means the clouds in stormy seasons become
arranged in these elevated parallel bars, which must be at
least 60 miles long, and are probably much more, considering
their elevation, and that both extremities are often invisible.

Of the Nature of the intermediate Modifications.

The conversion of the cirrus into the cirro-cumulus is 4
phenomenon which at some seasons may be daily traced,
and serves to confirm the opinion that there exists some-
what of the same difference between the cumulus and the
cirrus, as between a charged and a transmitting or an in-
fluenced conductor among solid bodies. On this supposi-
tion, the orbicular arrangement of the particles ought to take
place as soon as the mass has ceased to conduct from par-
ticle to particle, or to be so acted on by a contiguous con-
ductor as to have a plus and minus state within itsclf at the
same time: and as this sort of communication in a cloud
may he as slow as in other imperfect conductors, the equi-

A4 librium

i)

8 On the Modifications of Clouds, and

librium among the particles may be restored at one extre~
mity some time before the other has ceased to transmit 5
whence a visible progtess of the change which may be traced
in acirrus of sufficient length. :

That an extensive horizontal cirrus should become divi-
ded across its ramifications, and that these divided parts
should assume more or less of a round form, is also con-
sistent with the idea of a change of this sort*. It is not
‘so easy to give a reason why these small orbicular masses
should remain in close arrangement, or even in contact, for
several hours, forming a system of small clouds which yet
do not interfere with each other or run together into one,
but remain as it were in readiness to reform the cirrus,
which sometimes happens very suddenly, though they more
frequently evaporate by degrees. i

Fhe same remark must be applied to the curious and
as it were capricious divisions and subdivisions, both lon-
gitudinal and transverse, which happen in the cirro-stratus
when this cloud is verging towards the cirro-eumulus. In
general, nevertheless, its appearance is sufficiently distinct
from that of the cirrus and cirro-eumulus. The cirrus by

“its great extent in proportion to its mass, its distinct lines -

and angular flexures in all directions, and the cirro-cumulus
by the roundness and softness of its forms, indicates an €3-
sential difference in the state of the containing atmosphere.
The cirro-stratus appears to be always in a subsiding state,
slowly diminishing by evaporation or dispersion, and at the
saine time more feebly acted upon by electricity than the
preceding modifications. Indeed, the lower atmosphere 1s
usually pretty much charged with dew or haze at the time
of its appearance, and therefore in a state to conduct it to
the earth.

Of the Nature of the Compound Modifications, and of the
Resolution of Clouds into Rain, ec.

From the theory of evaporation it appears that no per-
manent cloud can bé formed’ in the atmosphere, however
low the temperature, without a sufficient pressure from va-
pour previously diffused. Hence, although in cold weather
the breath and perspiration of animals, as also water at a
certain excess of temperature, occasion a visible cloud, and,

* A quickly evaporating cumulus sometimes leaves a regular cirrns’
behind, formed out of the remnant of the cloud which in the interme-
diate state, and just when it begins to show the sky through it, ex-
actly represents the pores and fibre of sponge. This may be attributed
to the quantity of elsctrioity passing into or from the cloud at that time.’

. im

their Production, Suspension, and Destruction. 9

in fact, from the same cause as heretofore stated, (the water
first condensed being followed by undiffused vapour ;) yet
this cloud speedily evaporates again at all times, except when
precipitation is actually going on at large in the atmosphere
next the ground; when it 13 only dvspersed therein. By
comparing the different effects of a clear frosty air, and of a
misty though much warmer one, on the perspiration and
breath of horses warmed by labour, we may be assisted in
reasoning on the great case of evaporation, which, im some
sense, is the perspiration of the earth.

The most powerful predisposing cause of evaporation
appears to be a superior current in the atmosphere coming
from a region where the low temperature of the surface, or
its dry state, occasions a comparative deficiency of vapour.
Hence, after heavy rain in winter, we see the sudden evapo-
ration, first of the remaining clouds, then of the water on
the ground, followed by a brisk northerly wind and sharp
frost.

The very snow which had fallen on its arrival is some~
times totally evaporated again during the prevalence of such
awind. On the contrary, the first appearance of clouds
forming in cold weather gives us to expect a speedy remis-
sion of the frost, although the cause is not generally known
to be a change to a southerly direction already begun in
the superior atmosphere, which consequently brings on an
excess of vapour. é

This excess of vapour, coming with a superior current,
may be placed next to‘depression of temperature among the
causes of rain. *The simultancous decomposition of the
higher imported vapour, and of that which is formed on the
spot, or already diffused in the inferior current, would ne-
eessarily produce two orders of cloud, differing more or
less in electricity as well as in other respects. To the slow
action of these upon each other, while evaporation conti-
nues below, may be attributed the singular union which
constitutes the cumulo-stratus. [t is too early in the pre-
sent state of the subject to attempt to define the precise
mode of this action, or to say by what change of state a
cumulus already formed is thrown into this modification.
That the latter phenomenon is an clectrical effect, no one
who has had opportunity to see its rapid progress during
the approach of a thunder storm can reasonably doubt.

To assert that rain is in almost every instance the result
of the electrical action of clouds upon each other, might
appear to many too speculative, were we even to bring the
authority of Kirwan for it, which is decidedly in aes

this

10 On the Modifications of Clouds, &&c.

this idea: yet it is in a great measure confirmed by ob-
servations made in various ways upon the electrical state of
clouds and of rain, not to insist on the probability that a
thunder storm is only a more sudden and sensible display
of those energies which, according to the order observable
in the creation in other respects, ought to be incessantly
and silently operating for more general and beneficial pur-
poses.

In the formation of the nimbus, two circumstances claim
particular attention: the spreading of the superior masses
of cloud in all directions until they become, like the stratus,
one uniform sheet; and the rapid motion and visible de-
crease of the cumulus when brought under the latter. The
cirri, also, which so frequently stretch from the superior
sheet upward, and resemble erected hairs, carry so much
the appearance of temporary conductors for the electricity,
extricated by the sudden union of its minute drops into the
vastly larger ones which form the rain, that one is in a
manner compelled, when viewing this phenomenon, to in-
dulge a little in electrical speculations. By one experiment
of Cayallo’s, with a kite carrying three hundred and sixty
feet of conducting string, in an interval between two
showers, and kept up during rain, it seems that the su-
perior clouds possessed a positive electricity before the rain,
which on the arrival of a large cumulus gave place to a very
strong negative, continuing as long as it was over the kite.
We are not, however, warranted from this to conclude the
cumulus which brings on rain always negative, as the same
effect might ensue from a positive cumulus uniting with a
negative stratus. Yet the general negative state of the lower
atmosphere during rain, and the positive indications com-
monly given by the true stratus, render this the more pro-
bable opinion. It is not, however, absolutely necessary to
determine the several states of the clouds which appear
during rain, since there is sufficient evidence in favour of
the conclusion, that clouds formed in different parts of the
atmosphere operate on each other, when brought near
enough, so as to occasion their partial or entire destruction 5
an effect which can only be attributed to their possessing
beforehand, or acquiring at the moment, the opposite elec-
tricities.

{t may be objected that this explanation is better suited
to the ease of a shower than to that of continued rain, for
which it does not seem sufficient. If it should appear,
nevertheless, that the supply of each kind of cloud 1s by
any means kept up in proportion to the consumption, the

objection

Account of the Kookies or Lunctas. 11

objection will be answered. Now, it is a well-known fact,
that evaporation from the surface of the earth and waters
often returns and continues during rain, and consequently
affords the lower clouds, while the upper are recruited from
the quantity of vapour brought by the superior current, and
continually subsiding in the form of dew ; as is evident both
from the turbidness of the atmosphere in rainy seasons, and
the plentiful deposition of dew in the nocturnal intervals of
rain. Neither is it pretended that electricity is any further
concerned in the production of rain than as a secondary
agent, which modifies the effect of the two grand predis-
posing causes—a falling temperature and the influx of va-
pour.

The theory of rain, however, was not intended to be dis-
cussed in the present essay, which has already been ex-
tended to the usual limits. We may therefore conclude
with requesting, that those who possess the means, and
have acquired the habit of experimental observation, will
take suitable opportunities to submit to this test the pre-
ceding conjectures on the nature of several clouds. These
might haye been extended further, but that the author was
unwilling to go beyond the line which the experiments
of several eminent philosophers, and a few of his own,
seemed to point out as safe in the present state of the
subject.

The author thinks he cannot more properly terminate
this essay than in publicly acknowledging the obligation he
lies under to his friend Silyanus Bevan jun. for his frequent
and zealous aid in his observations and drawings.

I. Account of the Kookies or Lunctas: written by Joun
Macrar, Esq. and communicated to the Asiatic Society
by J. H. Harrincton, Esq.*

Tae Kookies are a race of people that live among the
mountains to the north-east of the Chittagong province,
at a greater distance than the Choomeeas from the inhabi-
tants of the plains ; to whom therefore they are little known,
and with whom they very rarely have any intercourse, ex-
cept when they occasionally visit the hauts, or markets, on

* From the Asiatic Researches, vol. vii. Mr. Macrae, author-of this
paper, is a surgeon in the honourable East India company’s service at
Chittagong, and received his information from a native of Runganeeah
who had long resided among the Ciicis as their captive.

the

12 Account of the Kookies or Lunctas.

the borders of the jungles in the Runganeeah and Aurunga=
bad districts, to purchase salt, dried fish, and tobacco.

The followmg account of then was taken from a native
of the Runganeeah district, who, when a boy, was carried
away, in one of their predatory excursions, and, after a
captivity of twenty years, found means to return to his
family.

The Kookies, or Lunctas (as they are also called), are the
least civilized of any of the people we as yet know among
these mountains : like all mountaineers, they are of an ac-
tive, muscular make, but not tall; they are stouter, and of
a darker complexion than the Choomeeas *, and, like them,
have the peculiar features of all the natives of’ ‘the eastern
parts of Asia, namely, the flat nose, small eye, and broad

round face.

The tradition of the Kookies respecting their origin is,
that they and the Mugs are the offspring of the same pro-
genitor, who had two sons by different mothers. The
Mugs, they say, are the descendants of the eldest, and the-
Kookies of the youngest son. The mother of the voungest
having died during ‘his infancy, he was neglected by “his
step-mother, who, while she clothed her own son, al-
lowed him to go naked; and this partial distinction being
still observed, as he grew up, he went by the name of
Luncta, or the naked. Upon the death ‘of their father, «
quarrel arose between the brothers, which induced the
Luncta to betake himself to the hills, and there pass the
remainder of his days. His descendants have continued
there ever since, and still go by the name of Lunctas ;
though, properly speaking, the term is only applicable to
the male part of them, as the females wear a short apron
before, made of cloth of their own manufacture, and which
falls down from the loins to the middle of the thigh; and
both sexes occasionally throw a loose sheet of cloth over
their bodies to defend them from the cold.

This tradition of their origin receives much support from
the great similarity of the Mug and Kookie languages, many
words of which are exactly the same, and their general re-
semblance is such that a Mug and Kookie can make them-.
selves understood to each other.

The Kookies are all hunters and warriors, and are divided
into a number of distinct tribes totally independent of each

‘* Choomeeas are the inhabitants of the first range of hills bordering
ov the plains to the north and east of the province of Chittagong, and
ave tributary to the honourable company ; their villages are called chsoms.

other,

Account: of the Kookies or Lunctas. 13

other, though all of them acknowledge, more or less, the
authority of three different rajahs, named Thandon, Man-
kene, and Halcha, to whom the various tribes are attached,
but whose power over them is very limited, except in that
tribe with which the rajah lives, where he is absolute. The
rajahships are hereditary, and the rajahs, by way of distine-
tion, wear a small slip of black cloth round their loins;
and, as a further mark of superior rank, they have, their
hair brought forward, and tied in a bunch, so as to over-
shade the torehead, while the rest of the Kookies have theirs
hanging loose over the shoulders. The females also of the
rajah’s family wear an apron of black cloth with a red bor-
der, which falls down to the knee,—a colour and fashion
paainiied to the rest of the sex, black being the royal co-
our.

The rajahs receive a tribute in kind from the tribes to
support their dignity ; and, in cases of general danger, they
¢an summon all the warriors to arms; but each tribe is
under the immediate command of its own particular chief,
whose word is a law in peace and war, and who has the
power of life and death in his tribe. The chieftainship is
not hereditary like the rajahship, but elective, though in
general the nearest relation of the Jast chief succeeds him,
if deemed by the tribe a proper person for the trust; and
the rajah cannot remove a chief once elected, should he dis~
approve of him.

The Kookies are armed with bows and. arrows, spears,
clubs, and daws, an instrument in common use among the
natives of this province, as a hand hatchet, and exactly re-
sembling the knife of the Nyars on the Malabar coast, which
is a most destructive weapon in close combat. They use
shields, made of the hide of the gyal, a species of cow pe-
culiar to their hills; and the inside of their shields they or-
nament with small pendulous plates of brass, which make
a tingling noise as the warriors toss about their arms either
in the fight or in the dance. They also wear round their
necks large strings of a particular kind of shell found in
their hills; about their loins, and on their thighs imme-
diately above their knee, they tie large bunches of long
pote hair, of a red colour; and on their arms they have

road rings of ivory, in order to make them appear the
more terrific to their enemies,

The Kookies choose the steepest and most inaccessible
hills to build their villages upon, which, from being thus
situated, are called parahs, or, in the Kookie language,
k-hooah, Every parah consists of a tribe, and has scldom

fewer

14 Account of the Kookies or Lunctas.

fewer than four or five hundred inhabitants, and sometimes
contains one or two thousand. Towards our frontiers, how=
ever, where there is little apprehension of danger, a tribe
frequently separates into several smal! parties, which form
so many different parahs on the adjoining hills as may best
suit their convemence. To give further security to the
parahs, m addition to their naturally strong situation the
Kookies surround them with a thick bamboo pallisade ; and
the passages leading into them, of which there are com-
monly four or five in different quarters, they strictly ouard
day and night, especially if there is any suspicion of dan-
ger; but, whether there is or is not, they are at all times
extremely jealous of admitting strangers within the parah :
they build their houses as close to each other as possible,
and make them spacious enough to accorimodate four or
five families in every house. They construct them: after
the manner of the Choomeeas and Mugs, that is, on plat-
forms or stages of bamboo, raised about six feet from the
ground, and enter them by ladders, or, more frequently, by
a single stick, with notches cut in it, to receive the foot:
underneath the stages they keep their domestic animals.
Ail these precautions of defence strongly indieate the con-
stant state of alarm in which they live, not only from the
quarrels of the rajahs with each other, but also from the
hostile feuds of the different tribes, not excepting those who
are attached to the same rajah. Depredations on each other’s
property, and the not giving up of such refugees as may fly
from one parah to another, are the most frequent causes of
quarrel; when they carry on a most destructive petty warfare,
in which the several tribes are more or less involved accord=
ing as the principals are more or less connected among them.
On these occasions, when an enterprise is not. of sufficient
importance to induce the chief to head all the warriors of
the parah, he always selects a warrior of approved yalour
and address to lead the party to be detached.

They always endeavour to surprise their enemy, in pre-
ference to engaging him in open combat, however confident
of superiority they may be. With that view, when on any
hostile excursion, they never kindle a fire, hut carry with
them a sufficiency of ready-dressed provisions to serve dur=
img the probable term of their absence ; they march in the
night, preceeding with the greatest expedition, and observ-
ing the most profound silence ; when day overtakes them,
they halt, and lie concealed in a kind of hammoe, which
they fasten among the branches of the loftiest trees, so that
tlrey cannot be perceived by any person passing undermeath.

From

Account of the Kookies or Lunctas. 15

From this circumstance of ambuscade, the idea has origin=
ated of their living in trees instead of houses. When they
have in this manner approached their enemy unperceived,
they generally make their attack about the dawn, and com-
mence it with a great shout, and striking of their spears
against their shields, If they are successful in their onset,
they seldom spare either age or sex : at times, however, they
make captives of the children, and often adopt them into
their families, when they have none of their own 3 and the
only slaves among them are the captives thus taken.

The heads of the slain they carry in great triumph to
their parah, where the warriors are met, on their arrival,
by men, women, and children, with much rejoicing ; and
they have the peculiar privilege of killing any animal in the
place they may choose (not excepting the chief’s), to be
given as a feast in celebration of their victory: but, should
the party have been unsuccessful, instead of being thus met
with every-demonstration of Joy, and led into the parah
amidst the exultations of its friends, it enters in the greatest
silence, and as privately as possible; and all the warriors
composing it remain in disgrace until such time as they
retrieve their characters, either jointly or individually, by
some act of valour.

The Kookies are often attacked by the Banjoogees, who,
though not so numerous a race of people, yet, from being
all united under one rajah, always prevail, and exact an
annual tribute of salt from the two Kookie rajahs Than-
don and Mankene, who, from having a greater intercourse
with the Choomeeas, receive a larger supply of this article
from the plains below than their more remote neighbours.
Salt is in the highest estimation among them all; when-
ever they send any message of consequence to each other,
they always put in the hand of the bearer of it a small
quantity of salt, to be delivered with the message, as €x-
pressive of its importance. Next to personal valour, the
accomplishment most esteemed in a warrior is superior ad-
dress in stealing: and if a thief can convey undiscovered to
his own house his neighbour’s property, it cannot after-
wards be claimed ; nor, if detected in the act, is he other-
wise punished than by exposure to the ridicule of the parah,
and being obliged to restore what he may have laid hold of.

This must tend to encourage the practice of thieving;
which, no doubt, is considered in such high estimation,
because the same sagacity and address necessary to give
success to the thief qualifics the warrior, in an eminent de-
gree, to steal unperceiyed upon and surprise his enemy, a

thus

16 Account of the Kookies or Lunctas. .

‘thus ensures him victory. So thought the antient warriors
of Sparta, who, like the Kookies of the present’ day, held
im estimation the man who could steal with superior ex-
pertness.

The Kookies, like all savage people, are of a most vin-
dictive disposition ; blood must alw ays be shed for blood;
if a tiger even kills any of them near a parah, the antislé
tribe is up in arms, and goes in pursuit of the animal;
when, if he is killed, the family of the deceased gives a
feast of his flesh in revenge of his having killed their rela-
tion. And should the tribe fail to destroy the tiger in this
first general pursuit of him, the family of the deceased must
still continue the chace; for, until they have killed either
this or some other tiger, and have given a feast of his flesh,
they are in disgrace in the parah, and not associated with by
the rest of the inhabitants. In like manner, if a tiger de-
stroys one of a hunting party, or of a party of warriors on
a hostile excursion, neither the one nor the other (what-
ever their success may have been) can return to the parah,
without being disgraced, unless they kill the tiger. A more
striking instance still of this revengeful spirit of retaliation
is, that “if a: man should happen to be killed by an accidental
fall from a tree, all his relations assemble and cut it down}
and however large it may be, they reduce it to chips, w hich
they scatter in the winds, for having, as they say, been the
cause of the death of their brother. They employ much of
their time in the chace, and, having no prejudice of cast,
or sect, to restrain them in ‘the choice of their game, no
animal comes amiss to them. An elephant ts an immense
prize for a whole parah. They do not remove their parahs
so frequently as the Choomeeas do their chooms: the
Choomeeas seldom remain — than two years on the
same spot, whereas the Kookies are usually four or five ;
and when they migrate they burn their parah, Jest the gyals
should return to it, as they are frequently known to do if
the huts are left ‘standing. The Kookies never go to a
greater distance from their old ground than a journey of
twelve hours, unless compelled to proceed further from
some. particular cause, such as the fear of an enemy, or the
want of a proper spot to fix upon.

Their great object in selecting a place to settle on, is
natural strength of situation, with a sufficiency of good
ground near the parah on which to rear the different grains,
roots, and vegetables they wish to cultivate. They cultivate
the ground as the Choomeeas do; and in this, as in every
other domestic occupation, the female sex bears the Yr

3 re)

Account of the Kookies or Lunetas. 17

of the labour, and no rank exempts them from it; the wife
of the chief and the wife of his vassal work alike in the
same field.

A proper spot being found on the declivity of some hill
contiguous to the parah, the men cut down the jungle upon
it in the month of March, and allow it to remain there
until sufficiently decayed. to burn freely ; when they set it
on fire, and thus at once perform the double purpose of
clearing away the rubbish, and of manuring the ground with
its ashes. The women now dig small holes, at certain di-
stances, in the spot so cleared, and into-each hole they
throw a handful of different seeds they intend to rear, which
are all jumbled together in a basket slung over the shoulder:
the seeds are then covered with earth, and left to their fate ;
when in due time, according to their various natures, the
plants spring up, ripen, and are reaped in succession: rice,
Indian corn, and the mustard plant, are thus seen in the
same field. Of rice they have a great variety, and two or
three kinds peculiar to the hills: one of these, the chereh,
is uncommonly fine, and has the peculiar quality of affect-
ing, as a laxative, persons not in the habit of eating it. The
other sorts are called beh, deenghroo, roomkee, sepooee, Lang~
soo, and boulteh; but it is not exactly ascertained, whether
or not these are different species of grain, or the same kind
receiving different names from the season of reaping it.
The leh is reaped in July, the chereh in August, the deeng-
kroo in September, the roomkee in October, and in Novem-
ber the seepooee, Langsoo, and loulteh. They have another
small grain called cutchoo, and a variety of beans, as the
harass, burguddee, and tooraee: the seed of the mustard
plant they cat, but express no oil from it. Of the gourd
and cucumber plants they have several kinds ; and turmeric,

ams, and tobacco, they cultivate; but the latter they have
in sinal] quantity, though very fond of it. |
In their forests they have abundance of honey, but are
ignorant of the method of separating it from the wax of the
comb.
Their domestic animals are gyals, goats, hogs, dogs, and
fowls; and of these the gyal is by much the most valued,
both on account of its milk and its flesh. As already men-
tioned, it is a species of cow peculiar to these hills, where
it is met in its wild state: in shape it resembles the heavy
strong make of the wild buffalo, but has much shorter
horns: its colour is brown, acquiring a lighter shade to-
wards the belly, which, as well as the legs, is often white:
its milk is nearly as rich as the cream of common cow milk,
«Vou, XVII. No. 65, By” and.

18 Account of the Kookies or Lunctas.

and its flesh constitutes the first luxury at a Kookie feast,”
and, except on very.extraordinary occasions, is never given.
The goats are larger and more hairy than those of the-plains.
In the other animals there is nothing peculiar. Notwith-
standing that the Kookies have such a number of different
articles of food, yet a-scarcity of provisions frequently pre-
vails among the tribes, when those upon a friendly footing
always assist each other ; and whatever may have been thus
amicably given is rigidly repaid, in more favourable times,
by the tribe which received it. A scarcity may be occa-
sioned either by the irrecularity of the season im a failure
or excess of the periodical rains; or else by the incursions
of enemies, who never fail to lay waste and destroy, if they
can, every thing to be found without the parah. And the
parah itself, in a fatally unguarded hour, is often destroyed
also; when the helplesssurvivors, if any, of such a calamity
are thrown upon the humanity of their neighbouring friends.

In the parahs they cook their victuals in earthen pots of
their own manufacture resembling those of the Bengalees,
but much stronger and thicker in substance. The hunter,
however, in his excursions through the forests, boils his
food in a particular kind of hollow bamboo. From the
ashes of a different species of the same plant he extracts a
substitute for salt to eat with his victuals; and with equal
simplicity and readiness he kindles his fire by the friction
of one piece of dried bamboo upon another. The Kookies
have but one wife; they may, however, keep as many con-
eubines as. they please. Adultery may be punished with in-
stant death by either of the injured parties, if the guilty are
caught by them in the fact; it may otherwise be compromised
by a fine of gyals, as the chief may determine. The frailty
of a concubine is always compromised in this way, without
disgrace to the parties. Fornication is punished in no other
manner than by obliging the parties to marry, unless the
man may have used violence; in which case heis punished,
generally with death, either by the chief or by the relations
of the mjured female. Marriage is never consummated
among them before the age of puberty. When a young
man has fixed his affections upon a young woman either of
his own or some neighbouring parah, his father visits her
father, and demands her in marriage for his son: her fa-
ther, on this, inquires what are the merits of the young
man to entitle him to her favour, and how many he can
afford to entertain at the wedding feast: to which the-father
of the young man replies, that his son is a brave warrior, @
good hunter, and an expert thief; for that he cam produce

Account of the Kookies or Lunctas, 19

so many heads of the enemies he has slain, and of the game
he has killed; that in his house are such and such stolen
goods; and that he can feast so many (mentioning the num-
ber) at his marriage. On hearing this, the father of the girl
either goes himself, or sends some confidential friend, to
ascertain the facts; which if he finds to be as $tated, he
consents to the marriage, and it is celebrated by a feast
given by him to the bridegroom and all their mutual friends,
At night the bride is led by her husband from her father’s
house to his own, where he next day entertains the com-
" pany of the preceding day, which is more or less numerous
according to the connections and circumstances of the par-
ties. When a chief marries, the whole parah is entertained
by him; and should his bride be from another parah, as
often happens, the two parahs feast and carouse with each
other alternately. At these, and all.their festivals, there is
much drinking of a liquor made of the rice called deengkroo,
of which the Kookies are very fond. There are two kinds
of this liquor; the one pure and limpid, and the other of a
red colour, from an infusion of the leaf of a particular tree
called bangmullah, which renders it highly intoxicating.
They indulge very freely in the use of both kinds, except
when they go on hostile-excursions: they then rigidly ab-
stain from them. In January and February they -usually
marry, because they have provisions in the -greatest plenty,
and it is their most idle time.

When any person dies in a parah, the corps¢ is conveyed
by the relations of the deceased, and deposited upon a stage
_ raised under a shed erected for the purpose at some distance
from the dwelling-house. While it remains there, it is
carefully guarded day and night from the depredations of
dogs and birds by some one of the family, and a regular
supply of food and drink is daily brought and laid before it.
Should more than one casualty occur in a family, the same
ceremony is observed with respect to each corpse; and at
whatever time of the year persons may happen to die in the
parah, all the bodies must be kept in this manner until the
11th of April, called by the Bengalees Beessoo. On that
day all the relations of the deceased assemble, and convey
their remains from the sheds to different funeral piles pre-
pared for them on a particular spot without the parah, where
they are burnt; as are also the several sheds under which
the bodies had lain from the period of their decease. After
this melancholy ceremony is over, the whole party repairs
to the house of him in whose family the first casualty oc-
curred in that year, and partakes of an entertainment en
by him in honour of the dead. On the following day a

Ba similar

20 Account of ‘the Kookies or Lunctds,

similar feast is given by him in whose family the next ca
sualty of the season had happened; and thus the feast goes
round in succession until one is given for each of the dead.

In this pious preservation of the dead till a certain day in
the year, when only the last solemn funeral rites can be
performed to their remains, there is a singular coincidence
in the practice of the Kookies with that of some of the
tribes of the North American Indians, as related in Ber-
tram’s Travels ; and it must appear.a curious fact, that in
so very particular an instance there should be this similitude
in the customs of two savage people placed in such oppo-
site parts of the world; where the climate, and other pecu-
hiar local. circumstances, are so totally different.

’The Kookies have an idea of a future state, where they
are rewarded or punished according to their merits m this
world. They conceive that nothing is more pleasing to the
Deity, or more certainly ensures future happiness, than de-
stroying a number of their enemies. The Supreme Being
they conceive to be omnipotent, and the Creator of the.
world and all that it contains. ‘The term in their language
for the Supreme Being is Khogein Pootteeang. They also
worship an inferior deity under the name of Sheem Sauk,
to whom they address their prayers, as a mediator with the
Supreme Being, and as more immediately interesting him-
self in the concerns of individuals. To the Supreme Being
they offer in sacrifice a gyal, as being their most valued ani-
mal; while to Sheem Sauk they sacrifice a goat only. In
eveyy parah they have a rudely formed figure of wood of
the human shape representing Sheem Sauk; it is generally
placed under a tree, and to it they offer up their prayers
before they set out on any excursion or enterprise, as the
deity that controls and directs their actions and destiny.
Whenever, therefore, they return successful, whether from
the chace or the attack of an enemy, they religiously place
before Sheem Sauk all the heads of the slain, or of their
game killed, as expressive of their devotion, and to record
their exploits. Each warrior has his own particular pile of
heads, and according to the number it consists of his cha-
yacter as a humter-and warrior is established in the tribe.
These piles are sacred; and no man dares attempt to filch
away his neighbour’s fame, by stealing from them to add
to his own. They likewise worship the moon, as conceiv-
ing it to influence their fortunes in some degree. And in
every house there is a particular post consecrated to the
deity, before which they always place a certain portion of
whatever food they are about to eat. In the month of Ja~
nuary they -haye a:solemn sacrifice and festival in honour

of

-

all

Avcount of the Kéokies or Lunctas. 2}

of the deity ; when the inhabitants of several neighbouring
parahs (if on friendly terms) often unite, and kill eyals and
all kinds of animals, on which they feast, and dance and
drink together for several days. They have no professed
ministers of religion, but each adores the deity in such
manner as he thinks proper. They have no emblem, as
of Sheem Sauk, to represent the Supreme Being.

The Kookies having no coms among them, but such ag
find their way from the plains, for the few necessaries they
want they barter their produce with the Choomeeas, who are
the medium of commerce ; and on these occasions the Choo-
meeas are never allowed to enter their parahs, but are obliged
to remain at a certain distance, whither. the articles of ex-
change are brought: such is their extreme jealousy of ad-
mitting any strangers within their parahs, as already no-
ticed. They frequently visit a Mug chief, commonly known
by the name of the Comlahpore rajah, who is settled among
the hills in the southern parts of this district, and to whom
they make themselyes understood from the similarity of lan-
guage. They can give no account of the country to the
eastward of their hills; but they have a tradition that it is
an open level country, like the plain of Chittagong. The
Kookies are a great terror to the Bengalces settled on the
borders of the jungles in the Runganeeah and Aurungabad
districts ; and a particular annoyance to the wood-cutters,
whose business leads them far into the forests, and whom
they have frequently surprised and cut off. Whenever an
unfortunate event of this nature has occurred, it has always
been remarked, that the Kookies carry nothing away from

-the slain but their heads, and such salt as they may have

with them. They stand so greatly in awe of fire-arms, that
the report of a single musket will put a whole party to flight:
on this account the rajah of the Choomeeas, who is so im-
mediately in their neighbourhood, keeps in his service a
number of Pehluwans, or men with fire-arms: but, not-
‘withstanding, his people have been obliged to abandon se-
veral places by the depredations committed by the Kookies.
Though the rajah is upon terms of friendship with some of
the tribes, yet, in the course of their migrations, these are
succeeded by others that he knows nothing of, and of whose
approach even he is ignorant until his people are cut off:
he is therefore under the necessity of being constantly pre-
pared to repel these attacks, which, from being always made
jn the night, it is impossible to guard against.
- The following is a specimen of the Kookie language ;
MORDRTT T s;\kn's; va LA,
B3 Noonaoo

22 On the Fecula of Green Plants.. G

Noonaoo ............ Woman.
IViRIO oie etgteetalicte sk 'oAehild.
Meepa Naoot’he ...... A male child.

Noonaoot’he ...... ... A female child,
BEE te cwisjsitays, ciate: MOtHET,
MEN viet sqscint « 92 .. Mother.
Chopooee ............+. Brother.
CREPMOO: < o50v 0 os wwe. SISter.
PPROO. 6 os cccevee veee Grandfathers
RNG ie ack" Y pite « 1 Siaisigces Grandmother.
Their numbers are reckoned thus: ,
WGRG aiding at lasorns. Ones
DBR, Pe des ald ath hiv biter Two.
TOQUE vtginl's '4\ Gxcniis .. Three.
Deekd. sidutesh awatd«s .. Four.
PUNTERS since ge A S016 Five.
HOORG: «aad hairs yank antes
SErCeRG asda -n nieie! les aie s Seven.
RG wndscereel Maan’ Eight. ‘
MROGRA cha Ris Manin uss ve Nine.
Son hat sie. wad eshte Ten.

By combining the first syllable of soomka with every in~
termediate number, as soomkatha, soomneka, soomtoomka,
and so on, they reckon to twenty, which is roloka.. The
same combination now takes place with roboka, the final
syllable ka being struck off; it goes on rolokatka, rolo-
neeka, &c., to thirty, which is expressed by soomtoomkay
or three tens. Forty is soomleeka, or four tens; fifty soom-
rungaka, or five tens; and so on to.a hundred, which is
expressed by rezaka. From vexzka the tinal syllable ka
being struck off, a similar combination, as above, takes
place with neeka, toomka, &c., to one thousand, called
saungka, The preceding rule of striking off the final ka is
observed with saungka ; and thus they go on to hundreds
of thousands, beyond which their ideas of numbers do not
extend, as far as could be understood, from their having nao,
terms to express them,

III. 4n Essay on the Fecula of Green Plants, By Pro-
fessor Proust. .

[Concluded from our last volume, p..128.]
VI. On Putrefaction.

Bor what then is putrefaction? A change’ respecting
which we haye yery few correct ideas,
When

On the Fecula of Green Plants. 23

When fecula, curd, flesh, or organized matters in general
have passed a certain period of that change which we are
accustomed to call putrefaction, they suddenly stop at a
permanent state, where unknown combinations seem to wait
for them, as if to salt and embalm them, as if to ensure
their duration in this new state, and to secure them from
further destruction.

When, for example, curd, fecula, gluten, flesh, have
passed through the stages of an infection often destructive,
and those derangements of colour and form which disfigure
them, and have at length attained, some to the caseous state,
vegetables and dunghills to that of mold, turf, poudrette,
and meat to such a state as not to be annihilated after fifteen
years of an ichorous stagnation, they all stop at that point
without being able to pass beyond it, and without ever
reaching, at least in our observation, that. final solution
which ought to terminate their existence, or reduce them to
an earthy inert matter,—zon absimile cineribus, as Stahl ex-
presses it; in a word, to a state where no trace is observed
of the radicals which organized them.

A putrefaction of this kind, strictly speaking, no where
takes place. But we no sooner perceive derangements in
the organization of an animal or vegetable matter, lividity
and bad smell, than we immediately imagine it is com-
mencing ; and we confound, without perceiving that we do
so, these appearances or phenomena which belong to a kind
of fermentation little known, with the effects of that de-
composition which alone ought to be accounted putrefac-
tion,—if its end accords with the ideas we entertain of it,
and if it be really that operation which nature has established
to analyse, or resolve into their ultimate elements, those
beings subjected to it.

Let us thence conclude that absolute putrefaction is 3
thing with which we are entirely unacquainted. But let us
return to fecula; it is time to review that which is sufh-
ciently divided to pass through the filter.

VII. Weshall take, for example, the filtered juice of cab-
bage, one of those which furnish fecula in the greatest
abundance; and the better to show the difference which
there is between this second fecula and albumen, we shall
subject the latter to the same tests. The white of an. egg
beat up in a pound of water, and filtered, will furnish the
liquor of comparison we require, é
| Ist. Immerse into water heated to 145 degrees two ma-
trasses, one with filtered juice and the other with albumen,
The juice a moment after becomes turbid, by caseous flakes

B4 which

24 On the Fecula of Green Plants.

which fall to the bottom. Albumen at that temperature
does not experience the slightest change.

ad. Place over a furnace two matrasses, one with juice
diluted in twenty parts of water, and the other with albu-
men. * But the fecula, however much diluted it may be,
will still be entirely separated by the heat. It is here that
it clearly shows its insolubility. In regard to the water of
the albumen, in proportion as it is heated it becomes opa-
lised without ceasing to be transparent: it boils and is
concentrated, without depositing flakes or any thing that has
a resemblance to fecula.. And if the evaporation be then
completed in an open vessel, it leaves nothing but a varnish
of white of egg. Darcet had before informed us that al-
bumen diluted with a large quantity of water is no longer
separable by heat. - Albumen is a soluble mucilage, fecula
is not; and the temperature which coagulates the latter
makes no change in the state of the former.

3d. Water of albumen may be kept several days without
alteration : on the other hand, the juice of plants is in a con~
tinual state of change, which always disturbs its transpa-
rency. When a juice is filtered it becomes turbid, and it
does not cease to deposit white fecula.

4th. Albumen makes the juice of violets incline to a
green colour, and reddens turnsole to blue. White fecula
when washed produces none of these changes: and how
should it? The juice of cabbages, hemlock, and many
other plants, makes turnsole red. Albumen however has
not the property of communicating a green of itself: we
know that it is indebted for it to a mixture of alkali.

5th. Alcohol separates from the water of albumen light
transparent shining flakes, which on the filter retain the ap-
pearance of baked white of egg. The juice of plants with
alcohol gives only an opake whitish powder, which spee-
dily falls to the bottom of the vessel.

6th. All acids, hydro-sulphurated water, and ammonia,
precipitate the fecula dissolved in juices; but these re-agents
make no change in water of albumen.

Oxygenated muriatic acid precipitates and oxidates white
fecula. The same acid first oxidates and then precipitates
albumen.

7th. Crystallized carbonate of potash, magnesia, muriate
of soda, muriate of potash, muriate of ammonia, nitrate
‘of potash, &c. when thrown into filtered juice force the
fecula, which is naturally very little soluble, to be precipi-
tated as it is dissolved. Water of albumen is not rendered
turbid by any of these salts,

Conse~

On the Fecula of Green Plants. 25

Consequences.

White fecula deposited spontaneously, or by alcohol, by
acids, salts, &c. is insoluble in water: on the other hand,
acids which precipitate fecula do not alter solution of albu-
men.

No salt is capable of separating albumen from water; but
the contrary is the case with fecula : it adheres so weakly to
water that there is not one of them which does not separate
it, and consequently oblige it to be deposited.

White of egg dried and eit to soften returns to the same
volume, opacity and whiteness, as baked albumen. The
case with white fecule is different: they acquire a strong
brown colour. The greater part even become entirely black
in drying, as those of cresses, cabbage, the solanum Licoper-
sicum, &c.; and if they become soft in water they never
assume the appearances observed in white of egg. Ina
word, this fecula is nothing else than a part of the gluten
which forms the base of green fecula. Thus, for example,
if the fecula.of white cabbage, separated by the filter, be
compared with that which the juice of it gives by heat, both
deprived of colouring matter, the smallest difference will
not be found. But it is the white fecula in particular which
dissolves easiest, because it 1s not, like green fecula, mm a state
of combination, which opposes its solution. All plants
contain a portion of giuten, which not having been vivified
by the light remains colourless.

Cabbage, succory, escarolle, and plants blanched by the
art of the gardener, give also white fecula, but in much
Jess quantity than when they remain green. The stem of
the cabbage and that of hemlock give pale fecula in com-
parison of that produced by their leaves. But vegetables
in general have not always need of being highly coloured
externally-to announce their abundance in gluten. The
small joubarbe gives abundance of well coloured fecula,
which is parcietarly rich in wax, as will be seen here-
rad

VIII, But it may be said, As albumen is the only product
which has been remarked to possess the property of coagu-
lating by. heat, it seems natural thence to conclude, &c.
But milk of almonds curdles also by heat, by alcohol, acids,
&c. This isa fact well known in apothecaries’ shops; and
yet it has never been concluded from this appearance that
emulsions contain white of egg ; because, even if characters
of animalization were observed in the principles of emul-

sion,

26 On the Fecula of Green Plants:

sion, it ought to exhibit other traits of a very striking na-
ture before it could be treated as aloumimous*.

It is under this point of view also that .we ought to con+
sider the gluten of fecula, since it is neither tenacious nor
elastic, nor susceptible of fermentation like that of wheat f.
Rouelle, in announcing it to chemists as a product analo-
gous to that of wheat, wished only to exhibit a part of the
characters which give them a similarity, those only which
belong to the nature of their constituent principles, since ex-
ternal characters of resemblance do not exist: my object
therefore, in defending the labours of that great master, is
much rather to maintain in the catalogue of his discoveries
that of an animalized matter found particularly in leaves,
than gluten properly so called, because this indeed is the
discovery which the author of the System of Chemical
Knowledge has rendered problematical in his work, Destroy
the aggregation in animalized matters ; deprive silk, horn,
wool, feathers, &c. of their form; it is evident then that,
considered in their constituents alone, they will be albumen,
gluten, febrine matter, any, every thing you please ; because,
if these constituents are every where the same, which has
never yet been examined, and what would be the only means
to establish the difference between them, would be to fix
the proportions according to which nature has united them
to give them existence.

But it may be added, If albumen does not issue from
juices with characters so striking as you desire, we must
pay attention to the extract, the salts and the acids, which
are always found along with it, and which must disguise
it a little: it is particularly in the water with which the
farina has been washed that you ought to search for it, to
find it in that state of purity which will leave no doubt in
regard to its nature. Let us see then what the washing of
the farina will exhibit.

* The comparison which Rouelle made of the green juice of plants ta
an emulsion rests on a much better foundation than he imagined. The
cheese separated from the milk of almonds by one of these means, when
washed and dried, gives-oil by expression, and then all the products of
caseum by distillation, This no doubt is the reason why almonds and
all kinds of nuts give by nitric acid so large a quantity of azote. ‘

The whey of almonds contains gum, a little extractive matter, and
sugar, which is either of the kind obtained from the sugar cane, or of
that which I discovered in grapes, and which I shall describe in speak-
ing of fermentation, :

+ The gluten of wheat is susceptible of a fermentation peculiar to it.
The gases thence disengaged in abundance are, the carbonic acid, and

hydrogen pretty pure, ae
TX. Water

On the Fecula of Green Plants. 27

IX. Water employed in washing’ farina, like the juice
recently filtered, is in a state of alteration, which continually
increases, and which does not stop till the acid which arises
from the fermentation of the saccharine principle has
finished the precipitation of the gluten.

All the acids and all the salts which we have: applied to
juices operate-in the same manner on the water of farina.
Alcohol produces the same effect: but vinegar does not,
because it dissolves the gluten. In aword, it is not by
coagulation that acids separate gluten from juices and from
the water of farina, since ammonia and salts do the same5
but rather by seizing on the solvent of a substance which
seems to derive its solubility from a pure and simple division,
and not from an afhinity comparable to that which unites
gums, sugar, and albumen to water.

Water of farina exposed to a heat of 145 degrees aban-
dons the gluten as it does the juice of plants. To dilute it
in a very large quantity of water is not sufficient to give
solubility to gluten: on the least exposure to heat it falls of.
itself.

I have» collected so much as an ounce of gluten which
heat separated from washings. Kept in its own moisture
it fermented, produced vinegar and ammonia. It is now
atter two years an obscure cellular mass, odorous and savoury
in the same degree as the cheese of gluten.

Let us then conclude that albumen has not’yet appeared
in vegetables. But we shall not therefore say that 1t cannot
be formed there as well as in animals. The age in which
we live, being more abundant than ever in- observations,
daily proves that there are but few products in either king
dom which can be considered as really exclusive.. It will
however be allowed, that to establish: the existence of al-
bumen by excluding the gluten of green plants, the learned
author of the System-of Chemical Knowledge has trusted
too much to the slender support of mere appearance. Before
he announced albumen he ought, in my opimon, to have
strengthened his first observation by more conclusive facts
than that of concrescibility alone. But let us not forget that,
in so vast an enterprise as this, it is difficult for an author
. cut out with equal.precision all the materials of his edi+

ce.

It will be with the same view that I shall extend these
conclusions to other products which Fourcroy, without suf
ficient examination, has placed among the glutinous sub-
stances of vegetables,

¢« There

28 On the Fecula of Green Plants.

<¢ There exists,’’ says he, ‘* anobservation more exact and
‘more positive than that of Rouelle in regard to the presence
of this glutmous matter im the vegetable tissue which forms
flax and paper,” &c.* To call the author’s attention to this
passage 1s sufficient. More details on my part would have
too much the appearance of censure. Fourcroy no doubt
will suppress it in a new edition, as well as that of the paste
of the mallows. If the paste of the mallows had a right
to assume a place among the animalized products of vege-
tables, we ought to place there also the paste of almonds,
paste of eggs, of marmalade, &c.

In regard to glue, which is found in the same chapter,
every bedy knaws that it is merely a kind of turpentine, an
inflammable aromatic resin, soluble in aleohol, which vege-
tation forms in the filamentous tissue of the holly; in the
fruit of the elder tree, its bark perhaps, and that of other
individuals, but under no point of view a glutinous sub-
stance.

X. Potash readily dissolves green fecula and divides it into”
two parts: one attaches itself to the solvent, and the other
separates itself under the form of a green powder which
cannot be attacked by new potash. This powder, when
washed and dried, gives by distillation the products of white
wood and of flax: that is to say, nothing ammoniacal.
This is the ligneous part, which is generally mtroduced into
fecula by trituration.

This solution has all the characters of an animal solution :
it exhales ammonia; it blackens the silver pan; and, by the
action of acids, emits effluvia which darken traces made by
white metals.

But here, as in soap from wool, a great part of the fecula
experiences a Sh eecianct which deranges the mode and pro-
portion of its radicals. Acids separate from it but very little
tecula: the rest assumes an extractive character which dis-
poses it.to unite with water. Neither alcohol nor acids can
separate this new extract from salts. It is of a fawn colour,
and muriate of tin precipitates from it an obscure lake. In
regard to the other, when collected and washed on a filter
it exhibits this singularity, that it has not lost the property
of crisping by the heat of boiling water,

Alcohol extracts from precipitated fecula a green colour
more charged than from that which ‘is fresh. This arises
from the resin, which is not destructible like gluten, at-

* Vol, yii. p. 296. :
taching

On the Fecula of Green Plants. 29

taching itself in greater quantity to that which has saved
itself trom destruction. In a word, this fecula gives by
distillation ammoniacal products.

XI. An acid of eighteen or twenty degrees of the areo-
meter disengages in abundance the azote from green fecula.
A stronger acid dissolves it with facility, and separates from
it a little of the powder, which is the ligneous remains of
the plant. With whatever ceconomy the nitric acid is ma-
naged, the oxalic acid is rarely obtained crystallized. It re-
solves itself into water and carbonic acid.

Solution of fecula always contains the bitter yellow of
Welter, sulphuric acid, benzoic acid, oxalate of lime and
tallow. If the solution of fecula charged with iron, that
of solanum licopersicon, be precipitated with acetite of
lead, a powder composed of oxalate and phosphate of lead
and of oxide of iron is obtained. By heating it with the
blowpipe the lead is burnt and even dissipated, and nothing
remains but a globule of phosphate of iron.

When a vegetable product contains azote, sulphur, phos-
phorus, benzoic acid, tallow, bitter yellow and iron in
abundance, one may rest assured that it belongs to the class
of animalized substances.

Of Wax.

XII. Wax is the work of vegetation, and not of bees.
{t is, in my opinion, by nourishing themselves with the
gluten, which accompanies it in the farina of the stamina,
that they effect a separation of it. This farina gives abun-
dance of ammonia, which induces me to believe that it
eontains gluten ; and at present, since J have discovered wax
in certain fecule, T presume that if this farina were treated
with nitric acid wax might be found in it.

Fecula of the small joubarbe gave me a quantity which
surprised me. This wax is white, dry and brittle, and has
no smell: it cannot be confounded with the schaceous pro-
ducts given by other feculze, those of hemlock and of the
solanum. Messrs. Fernandez and Chabancau, to assure
themselves of it, examined it, chewed it, and were ccnyinced
that this product ts nothing else than perfect wax.

The fecula ef green cabbage gave me some of it also, but
much less. Wax appears to mé ro be the varnish which
vegetation extends over plants to secure them no doubt
from the effects of mouldiness, which might injure their
health. It is this varnish which divides rain and dew into
pearly drops on the cabbage leaves, those of the poppy, and
many others which exhibit to us that agrecable spectacle in

. 3 our

30 On the Fecula of Green Plants.

ourgardens. It is this wax that the curious gardener, when
he presents a plum, a fig, or a bunch of grapes, is so de-
sirous of preserving, that he avoids touching them as much
as possible with his fingers.

At Paris, when an orange is taken from the paper cover=
ing in which it has been conveyed from Portugal, it 1S seen
covered with a farinaceous coating, which may be removed
by the blade of a knife, and applied to a taper to melt it
and ascertain its nature.

The fecula of opium contains also akind of tallow which
approaches near to wax by its strong consistence, and which
several apiologists have mentioned.

Raw silk also is covered with wax, which alcohol removes
from it along with its colour, and which.is separated from
it by cooling.

Of some Fecule less known.

XIII. When five or six pounds of saffron are treated to-
gether, to obtain from it the volatile oil and extract, there is
observed in the decoction a fine dust which renders it turbid,
deposits itself, and may be separated by straining through a
eloth. This powder when washed shrinks on drying, and
becomes grained like green fecula in summer: it speedily
becomes putrid, and filled with worms, if not carefully pre-
served. This fecula’by heat gives all the products of gluten.
With alkalies and lemon juice it communicates to silk a
very brilliant yellow dye.

Borage.

A plant may contain gluten in two states; one in the fe-

cula, and the other dissolved in its juice by means of pot-

ash: of this kind is the juice of borage: when clarified it
is thick and of a sea-green colour; some drops of acid se-

parate from it a cascous curd, which is collected by the filter, -

and which is nothing else than gluten.

Elder.

Elder berries, amidst a juice strongly coloured, exceedingly
gummy, and slightly saccharine, contain a fecula as green
as that of spinach. When it has been well freed from the
red colour, alcohol extracts from it a green tincture: the
rest is gluten, which is in nothing different from that of
fecula. «

When these berries are bruised their glue adheres to the
fingers ; it has the same consistence as that of holly. Their
juice left to ferment gives a verysmall quantity of spirit,

which

Journey to the Summit of the Peak of Teneriffe. 31

which has a disagreeable odour. It is followed by an asto- —
nishing quantity of very good distilled vinegar.

Buck-thorn.

The juice of buck-thorn, which contains a bitter nauseous
extract, gum, and a little sugar, is thickened by a greenish
dirty matter, which is separated from it by heating it and
leaving it to ferment. This pulp when well washed is of a
bright green colour: it is gluten mixed with a little febrine
matter: it gives carbonate of ammonia, &c.

Rose.

Its petals triturated furnish fine fecula slightly coloured,
which gives the same products as gluten.

Grapes.

, Feeula is found in great abundance in grapes: it forms
the lees in wine: but to speak of this product would
be anticipating what I have to say on fermentation.
Gluten is found also in quinces, apples, and no doubt in
other fruits ; 1t is found in the acorn, chestnut, horse-chest-
‘nut, rice, barley, rye, pease and beans of all kinds. I[
shall resume the subject hereafter, on the difference between
wheat which has germinated and that which has not under-
gone this operation.

IV. Account of a Journey to. the Summit of the Peak of
Teneriffe: in a Letter from L. Corpier, Engineer of

_ Mines, to C. DEVILLIERS junior *.
Santa-Cruz, in Teneriffe,

MY DEAR FRIEND, May 1, 1803.

T wave terminated my seventh geological campaign by a
most interesting excursion. I had examined, with Neer-
gard, the extinguished volcanoes in the centre of France.
In the Pyrenees and Catalonia we discovered the immense
remains of the antient strata of the globe, and the manner
in which they have been covered by modern strata, which
contain vestiges of an antique organization having no re-
semblance to that of the present age. I followed these ob-
servations in the interior of Spain, in the Sierra-Morena, as
far as the famous Strait of Gibraltar, where my conjectures
on the forces which determined the ultimate form of the
continents received a new degree of probability. I had met

* From the Journal de Physique, Messidor, an. 11, +e
with

32 Account of a Journey to the

with almost all the species of strata which enter into the
composition of the globe, including rock salt, bitumen, and.
sulphur. In the last place, I had conceived an idea of some
of those memorable epochs when Nature exercised the ener-
getic power she formerly possessed of creating and destroy-
mg, of raising or depressing, in order to bring our planet to
its present state. It remained for me to go to one of those
sanctuaries to which she in some measure retired after finish-
ing her labour, where her activity is from time to time
awakened, and gives proofs of existence which are sufficient
to occasion terror and desolation among us. Do you not
agree with me in opinion, that it is there only that one can
be able to conceive by analogy the kind and the energy of
the means which she must have displayed tm the earliest pe
riods? The hope of acquiring some ideas in regard to the
Atlantide fixed my determination. And, indeed, could I
venture to form conjectures respecting the existence of that
country so celebrated and so problematical, but on the peak
of Teneriffe ?

We left Cadiz on the 4th of April, and had a pleasant
passage: ashark, two tortoises, and a kind of spermacett
whale, were the only living objects we met with. I made
some researches, but without success, in regard to those
phosphorescent bubbles which appear in the sea water during
the dark. On the 11th I traversed with eagerness a soil al-
most unknown to the naturalist. I beheld with pleasure
the palm tree, the cotton shrub, the cactus, the coffee, and
the banana tree, amidst a variety of others with which I
was entirely unacquainted. The olive tree of Madeira, olea
madeirensis ; the tree which produces dragon’s blood, dra-
cena draco; the lignum rhodium, and convolvulus floridus
which produces the rose wood so valuable, and an immense
quantity of large euphorbias, among which were the eu-
phorbiq canariensis and the euphorbia mauritanica, attracted
my attention as much as the broad triangular faces and yel-
Tow complexion of the inhabitants of the country. It is
easily perceived that their blood is mixed with that of the
antient islanders. I have since thought that it might be a
punishment of nature, who took advantage of the inconti-
nence of the conquerors to preserve the remembrance of
their ferocity, by imprinting on the figure of their descend-
ants the features of the Guanches, whom they cruelly de-
stroyed, and with so little advantage. ;

On the 15th J was on the northern coast of the island:
my instruments were repaired at nine in the morning, and
I had removed the obstacles which ill-founded opinion had
i. opposed

Summit of the Peak. of :Tenexiffe. 33

opposed to my enterprise of ascending the peak so early in
the season. It is to be remembered that two gentlemen in
the suite of lord.Macartney were not able to succeed in the
month of October 1792; on account of the,cold and snow ;
and that at a later period captain Baudin was in danger of
perishing there in the month of December. No person,
therefore, was tempted to accompany. me;

At six o’clock in the morning of the 16th’I left the port
of Orotava, trusting to the fine weather, and still more to
my being accustomed to the snow and ice in the high moun-
tains. I had with me a guide, a mule laden with water and
provisions, and a mule driver. The peak stands in the
southern part of the island, on an eminence which rises |
more than 1100 toises above the level of the sea. -The day
was employed in ascending to the bottom of this colossal
peak.

Less time could not be employed in passing from the
tropic to the polar ice. We travelled for five hours over
gentle acclivities covered with the richest and most luxu-
rlant vegetation. All the flowers in bloom exhaled the
most delicious perfume, and the mildness of the tempera-
ture was equal to the sweetness of the-air. On this occa~
sion I could not help calling to mind Tasso, Armida, and
the delights of the Fortunate Islands of antiquity. We
were a long time in the middle of an immense wood of lau-
rels, and a tall kind of heath, the elegant stems of which
were covered with white blossom. Pines then announced
to us a soil more ungrateful, because more elevated. The
lava of currents, hitherto concealed by vegetation, began to:
appear in all their aridity and confusion. The pines were
soon succeeded by a large species of broom, spartiwm su-
pranubium, which extends to the eminence, where its dis-
mal bushes, scattered over heaps of scoriz or plains of vol-
canic sand, participate only with some lichens, the property
of the driest and most arid desert that can be imagined.

We halted on a small sandy plain of pumice stone, bor-
dered by two enormous currents of vitreous lava: some.
blocks of this lava, ranged in a semicircle, form here what
is called stanza de los Ingleses, where we reposed. for the
night under a most beautiful sky. The barometer stood at
19 inches 9*5 lines, and the thermometer at 4°9 degrees.
According to a corresponding observation made at the port,
we were 1529 toises above the level of the sea. I was much
astonished to see the broom, but indeed stunted, live at that
elevation. A good fire which we made defended us from
the intenseness of the cold.

_ Vou. XVII. No. 65. C The

34 Account of a Journey to the”

The night was deljghtful, without a cloud, and scarcely
a breath of air stirrmg. The colour of the sky appeared to
be a very intense black: the stars sparkled with an exceed-
ing bright light, by the help of which we faintly perceived
the obscure vapours that veiled every thing below us.
Every time I rose to observe the thermometer, I employed
a considerable time in enjoying the charms of so rare and
so beautiful a situation. Raised to that height in the at-
mosphere, seated quietly on that enormous mass of smok-
ing ruins insulated in the ocean, being alone awake amidst
the silence of nature, I admired with religious awe the ma-
jesty of its sleep; I recalled past events, and waited with-
out impatience for the hour when I[ was going to satisfy the
euriosity which had brought me so far to visit one of the
oldest volcanoes of the earth.

At a quarter before five the thermometer fell to three
degrees below zero: It was now day-light, and I set out
with my guide. The acclivities are rapid, and formed by
heaps of ruins which cover the currents. We had always to
clamber up Jarge masses of scoriz and vitreous lava ex-
eeedingly sharp and rough. The snow retained in the fur-
rows formed by the currents was fortunately solid. I took
advantage of it to ascend from time to time in a less paintul
manner. ‘Towards the summit we no longer found any
thing but pumice stones, exceedingly fatiguing by their in-
elination and mobility. Without advancing too fast, we
arrived at the end of three hours at the summit of the peak.
To look to the bottom of the crater then behind me, and to
survey the ummensity of the horizon, was the affair of a
Moment; to enjoy the accomplishment of a project which
1 had long formed, was the affair of a second. The former,
my dear Devilliers, was certamly worth the latter.

When my first eagerness was satisfied, I ensured my po-
sition on the most elevated edge. It is impossible to walk
round the crater: it is necessary to remain on the northern
part by which you have ascended. It appeared to me proper
to place my mstruments a little lower, to shelter them from
the sulphureous vapours which the wind agitated above the
erater before it carried them away. When I returned to my
post I hoisted a flag; to announce my success to my good
friends at the port of Oratava, and I quietly communicated
to them the observations IT had made. A line of vapour
marked out on the horizon the separation of the sea and the
air, forming aa immense and perfect circle. On the smooth
surface of this truly boundless plain arose the isles of Ferro,
Canary, Gomera, and Palino, which seemed to crowd rise

at

Summit of the Peak of Teneriffe. 33

that awful mass which hangs over them. Each of them
was ornamented with a band of light clouds, which extended
several leagues in the north-east in a direction contrary to
that of the trade wind. The sun, now near the tropic, dif-
fused in tranquillity a most splendid light over the waters
of the ocean. The atmosphere was as pure and as ttans-
parent as it was calm: My sight; however, was not suffi-
ciently strong to distinguish the islands of Fuerte-Ventura
and Lanzarotta, the profile of which was designed in the
horizon at the moment of sun-rise: but I saw distinctly
every thing around me; and, with the famous passage of
Plato in my hand, I was able to examine whether I wag
standing on the remains of the Atlantide.

This research was naturally connected with the most ge-
neral observations ; but I soon found that it ought only to
be aconsequence of them. I obtained in succession all the
proofs I could desire of the distinction which I had already
made of two orders of volcanic matters: The modern lava
has been thrown up ‘amidst the ruins of an antient system
of ejected matter much older, the immense fragments of
which form the skeleton of the island, and sustain the emi-
nence on which the peak is raised. ‘Their greatest ridges,
turned towards the summit, rise to more than 300 toises
above all the new products. heir torn flanks exhibit 2
series of thick strata, almost all declining towards the sea,
and composed alternately of ashes, volcanic sand, pumice
stone, and compact lava often prismatic, porous lava and sco-
riz. An innumerable quantity of new currents, which have
flowed down from the peak, or which have issued from its.
sides, mark out a multitude of irregular furrows, which turn
round or pass along the edges of these antique masses, and
lose themselves in the sea on the western and northern side.
More than eighty craters are dispersed throughout these cur-
rents, and increase with their remains the confusion which
seems every where to prevail: in a word, the subterranean
agents have not even respected the evidences and remains of
their antient energy; they haye pty in many places the
shreds of the antient strata, and new ejected matters have
freely extended themselves over their declivities.

This antient volcanic system extended much further be~
fore its destruction: several of its enormous fragments
insulated in the sea are a proof of it. It has been de-
stroyed by forces similar to those which have opened the
last valleys on the continents: this is proyed by the form

apd respective position of the ruins. But is its destruction

C2 te

36_ Account of a Journey fo the ~

to be ascribed to one and the same period? I am inclined
to think it is but in consequence of probabilities deduced
from all the facts which relate to that grand epoch.

I shall not speak in detail of all those observations which
cannot appear insulated; such as the existence of obsidian
stone and petro-silex in currents, the incontestable transi-
tion of obsidian stone to pumice stone, &c. My position
was too favourable not to take advantage of it in every man-
ner possible. I rectified by the compass the large chart
published by Lopes; and I several times repeated the only
experiment I could make on the magnetic needle, namely,
that on its inclination I always found it more than five de-
grees towards the south pole. At the height at which I was
placed, the solar rays had not yet traversed two-thirds (in
weight) of the atmosphere. I shall add some remarks to
those I have already made on the origin and distribution of
free heat in the atmosphere, in regard to the intensity of the
rays, the density of the strata, and the height above the
earth. :

The puffs of vapour which warmed me from time to
time, at length attracted me into the crater. One can de-
scend into it only by three indentations: its edges are per-
fectly steep in the inside, and highest towards the north:
it is of an elliptic form, and may be about 1200 feet in
circumference and 110 in depth. Proceeding from the steep
edges, the declivities consist of a snow-white earth, which
forms a contrast with the beautiful orange colour and the
bright splendour of the crystals of the sulphur which cover
. all the still solid masses. This earth results from the de-
composition of the blackest and hardest vitreous and por-
phynitic lava: it is continually softened by a very hot mois-
ture; one therefore glides rather than descends to the bot-
ton of the crater. The whole, however, is solid; and the
lowest part is occupied by blocks, which crumble down from
the steep edges according as these matters are decomposed,
and sink into the interior of the gulf.

. The vapours, which issued in abundance from among
_these blocks and an infinite number of crevices, certainly
came from.the depth of several leagues, and retained a great
intensity of heat. The thermometer exposed in a crevice
speedily rose to 80-degrees, and no doubt would have risen
higher had the tube been longer. To my great astonish-
ment, I found that this scorching vapour was composed
only of sulphur and water perfectly insipid. I searched, but
in vain, for traces of sulphureous acid, soda, and hydrogen

fag.

Summit of the Peak of Teneriffe. 37

was. What surprised me most, was to find close to the in-
crustations of sulphur, which it forms in a short time, real
opal in thin mamellous plates.

Having ascertained the discovery of a formation so sin-
gular, I ascended, to terminate by barometric observations.
I shall here mention only the first, because the rest cave me
the same results in the calculation, a few differences more
or less excepted. At eight o’clock, at the distance of a
toise and a half from the summit, the barometer was at
18 inches 4 lines, and Reaumur’s thermometer at 6°9 de-
grees. At the same hour, Mr. Little, an Englishman, who
observed at the port with excellent instruments, the preci-
sion of which J had verified, found the barometer at 28
inches 5°6 lines, and the thermometer at 19-9 degrees:
the station was seven toises above the level of the sea. The
result of these data, corrected according to Deluc’s method,
and then increased: by eight toises and a half, makes the
height of the peak to be 1901-2 toises above the level cf
the sea.

This is far from the height of ten Italian miles, assigned
to it by Ricciolo and Kircher; and the latter is nothing in
comparison of che 15 marine leagues ascribed to it by Tho-
mas Nicols. Why then should people convert into fabu-
lous wonders every thing great and curious produced by
nature? Do they imagine that by every thing they add in
their extravagant accounts they increase the feeble merit of
having seen them ?

What has been said in regard to the intensity of the cold,
the weakness of spirituous liquors, and the difficulty of re-
spiration on the peak, is not more correct. Ina word, I
haye several times found by experience that the opinion
generally received in this respect is more than exaggerated.
{ assure you that the cold was very supportable ; that liquors
had Jost none of their force; that the hydro-sulphureous
vapours* were not injurious to respiration; and that we
suffered no inconvenience from the rarity of the air, though
it obliged us to make frequent pauses on approaching the
summit. In the last place, what has been said, and often
repeated, in very modern works respecting the appearance

* The author means aqusso-sulphureous, since he says that the vapours
are composed only of pure water and sulphur. ‘This proves, as 1 have
already observed in the preliminary discourse in the Journal de Physique,
year 9, that when we wish to express the combinations of inflammable
gas with sulphur and other substances, we ought not to say bycdio-sulphu-
reous but hydrogenn- sulphureous, according to the principles of tue new

r

nomenclature.— Nore of Delametherie. ,
C3 a

38 Account of a Journey to the

of the sun’s disk as seen from the summit of the peak, is
absolutely false.

The enjoyment of three hours and a half soon elapsed.
This was littlé, no doubt, in comparison of the eight hun-
dred leagues which I had travelled to procure it; but these
hours, such as I spent them, were and always will be to
me of infinite value. I had scarcely time to arrive at the
port of Orotava with day-light; and I had still to make spe-
cimens of all the different kinds of lava, I was obliged to
quit for ever one of the most beautiful scenes in nature ;
and [ quitted this famous summit, bidding it, with regret,
an eternal farewell.

We descended very speedily: the lava, which had ren-
dered our efforts exceedingly laboricus, crumbled to pieces
under our feet. We therefore soon passed das norices deb
pico, two small spiracles at the bottom of the pap, which
continually throw up water and vapour. The snow soft-
ened by the sun was less dangerous, but [ often sunk into
ii up to the knees; which was not very tempting to my
guide, who had not ventured to trust himself to it in as-
cending, and who was afraid of sinking into it altogether.
We stopped for a moment near la cuvea eel gelo. This
is one of those wonders to the vulgar, respecting which so
many fables are told by travellers, You will have an idea
of it, if you imagine one of those vaults which the liquid
lava forms above itself to have burst exactly over a large
cavity, the bottom of which is filled with snow abundantly
impregnated with water: in summer it is sometimes dry,
At a quarter before one we arrived at La Stauze, somewhat
fatigued with the carriage of my valuable and heavy collec-
tion.

Our small caravan soon set out, but at a slower pace. Till
that moment, the rapidity of our march and the multitude
of observations had scarcely permitted me to breathe. In
descending I had time to reflect on every thing by which I
had been most interested, and it was then only that I began
to enjoy what I had seen. In this satisfactory account
which I gave to myself, I soon discovered an error, which .
was, that I had not attempted to ascertain whether there
existed any thing remarkable at the bottom of the peak to-
wards the south-west, This fault could not be remedied.
You will soon see that it was a great one, and whether it
was properly repaired eight days after.

The state of the atmosphere had changed since the morn~
ing. The clouds, now united, formed only a moveable stra-
tum on a level with the heights, and which the trade-wind
4 carried .

Summit of the Peak of Teneriffe. 39

earried before it without breaking: we had not time to tra-
verse it before sun-set. The declivity of the ground, and
the darkness, rendered our march excéedingly painful till
we reached the first habitations ; where our guide soon kin-
died some pieces of split fir-woed, by the light of which
we continued our route; and arrived at the port of Orotaya
at nine in the evening. I found my friends uneasy at my
long delay: they had distinctly observed the flag which I
hoisted in the morning.

I have not time to add any thing further to this sketch of
one of the most interesting journeys that those who occupy
themselves with the structure of the globe can undertake.
Since that time I have not neglected any opportunity of
multiplying or verifying my observations. I have collected
the most singular notions in regard to the internal compo-
sition of more than 600 medern currents of lava. What
would become of our numerous systems in regard to yolca-
noes, if it be true that we have hitherto been acquainted
only with the superficial part of their productions, scorize
tae porous lava? This is as if we were to judge of different
liquors without seeing any part of thei but the foam.

The eruption which choked up the port ef Guarachice
in 1706 was attended with this peculiarity, that the current
traversed sixteen leagues in five hours: the extremity of it
has been carried away by the sea. One may observe that it
is composed of prismatic basaltes, black and somewhat
porous, with large crystals of augite and olivin.

The last eruption took place in 1798. New mouths,
three in number, were opened on the declivity of an enor-
mous prolongation of the base of the peak towards the south-
west, 1270 touises above the level of the sea. As the form of
the mountains on this side justified my regret, I made every
effort to repair my fault; and I can now say, that of all the
travellers who preceded me, I ascended quietly for three
hours along the ‘declivities of the prolongation. When I
reached the height of 1600 toises -I found myself on the
edges of a vast crater, to which none of those we are ac-
quainted with can be compared: it is nearly a league and a
half in circumference. Though very old, it is exceedingly
steep in the jnside, and still exhibits the image of the most
dreadful violence of the subterranean fires. The peak has
been raised on the edges of this immense mouth. The im-
possibility of walkimg round the summit of the peak, or
rather the custom which travellers have of exactly following
the traces of their predecessors, is no doubt the cause of
‘this curiops fact haying hitherto remained unknown,

C4 My

40 On Mr. Arthur Woolf’s improved Apparatus,

My second:ascent of the peak was not only a lesson: it
furnished’ me, as well as my researches respecting an erup-
tion which took place in 1705 at Guimar, with a number
of facts, of which I wish I were able to give you an ac-
count. But I must be contented with assuring you that
few of my journeys have afforded me so much satisfaction
as the present. I had every assistance and aid J could de-
sire, both from individuals and from the Spanish govern-
ment. I shall never forget the reception I met with from
the marquis de Perlasca, the governor-general of the islands ;
and from the marquis de Casa Cajigal, who commands under
him,

V. On Mr. Antuur Woo r’s improved Apparatus, ap-
~ plicable to Steam Engines and other Purposes of Art and

Manufacture: including a Description of two Boilers now
. erecting qt Messrs. Meux’s Brewery.

Ma. Wootr’s improved apparatus consists, First, of two
er more cylindrical vessels properly connected <ogether, and
so disposed as to constitute a strong and fit receptacle for
water, or any other fluid intended to be converted into steam,
whether at the usual heats or at temperatures and under pres-
sures uncommonly high; and also to present an extensive
portion of convex surface to the current of flame, or heated
air or vapour from a fire: Secondly, of other cylindrical
receptacles placed aboye these cylinders, and properly con+
nected with them, for the purpose of containing water and
steam, and for the reception, transmission, and useful ap-
plication of the steam generated from the heated water or
other fluid; and, Thirdly, of a furnace so adapted to the
eylindrical parts just mentioned, as to, cause the greater part
of the surface of all and each of them, or as much of the
said surface as may be convenient or desirable, to receive
the direct action of the fire, or heated air and vapour.
That our readers may be able fully.to comprehend the
way in which Mr. Woolf constructs his apparatus, we shall
present some plans and views, with such a description as
will, we hope, convey a pretty correct idea of their nature.
Ng. 1. (Plate I.) represents one. of his boilers in its most
simple form, It consists of eight tubes marked a, made of
cast iron or any other fit metal, which are each connected
with the cylinder A placed above them, as shown in the
side view fig. 2, in which the same letters refer to the same
parts,

applicable to Steam Engines, &c. | 4)

parts as in fig. 1. In fig. 2. 1s also shown the way in which
the fire is madeto act. The fuel rests on the bars at B, and
the flame, heated air and vapour, being reverberated from
the part above the two first smaller cylinders, goes under
the third, over the fourth, under the fifth, over the sixth,
under the seventh, and partly over partly under the eighth
small cylindric tube. The direction of the flame, till it
reaches the last-mentioned tube, is shown by the dotted
curved line and arrows. When it has reached that end of
the furnace it is carried by the flue C to the other side of a
wall, built under and in the direction of the main cylinder A,
and then returns under the seventh smaller cylinder, over
the sixth, under the fifth, over the fourth, under the third,
over the second, and partly over partly under the first; when
it passes into the chimney. The wall before mentioned,
which divides the furnace longitudinally, answers the dou-
ble purpose of lengthening the course which the flame and
heated air have to traverse, giving off heat to the boiler in
their passage, and of securing from being destroyed by the
fire the flanges or other jomings employed to unite the
smaller tubes to the main cylinder. The ends of the smaller
cylindric tubes rest on the brick-work which forms the sides
of the furnace, and one end of each of them is furnished.
with a cover, secured in its place by screws or any ether
adequate means, but which can be taken off at pleasure, to
alloy, the tubes to be freed, from time to time, from any
incrustation or sediment which may be deposited in them:
‘To any convenient part of the main cylinder A, a tube is
afhxed, to convey the steam to the steam-engine, or to any
vessel intended to be heated by means of steam. -

. When yery high temperatures are not to be employed,
the kind of boiler just described is found to answer very
well; but where the utmost force of the fire is desirable,
Mr. Woolf, for a reason which shall be afterwards men-
tioned, combines the parts in a manner somewhat different,
though the same in principle. Having been permitted to
inspect two boilers of this kind which he is now erecting
in Messrs. Meux’s brewery, and even to take copies of such
parts of the plans as were necessary for our present ptirpose,
we persuade ourselves a short description of an apparatus so
curious, aud at the same time so useful, will prove highly
acceptable to our readers,

In fig. 3, A is the main cylinder crossing the smaller cy-
Jinders a,a.a, half way between their middles and ends, but
not joined to them at the points at which it crosses them.
ft is put in this place that it may come oyey that part of the

| ' furnace

42 On Mr. Arthur Woolf’s improved Apparatus,

furnace S,S,S, through which the flame first passes, and re-
ceive its direct action, which it does over nearly a half of
its surface, as may be seen by looking at the vertical section
A SS, fig. 6. The smaller cylinders have a communication
with the main cylinder in the following manner :—Three
cylinders, CCC, are placed parallel to the main cylinder A,
over the part of the furnace by which the flame returns, in
such a manner that each of the cylinders C CC takes in three
of the smaller cylinders aaa, being united to and con-
nected with them as shown in fig. 4, which is a longitu-
dinal vertical section of that part of the apparatus. The
cylinders CCC have a direct communicat.on with the main
cylinder A by the pipes or tubes PPP, as may be better
seen by the cross vertical section, fig. 6, in which the same
parts are marked with the same letters as in figures 3 and 4.
The three tubes C CC are preferred to one long tube, to pre=
vent any derangement taking place in the furnace or in the
tubes, by the expansion and contraction, occasioned by
changes of temperature, which is more considerable in one
tube of the whole length cf the furnace than when divided
into three portions; and it is for the same reason that the
tube A is not made to communicate directly with the smaller
tubes aaa, but mediately by means of the tubes marked
C and P.—N.B. The two outermost of the tubes marked P,
instead of going parallel to the middle tube P, may both be
inclined towards it, as one of them is from m, so as to join
the cylinder A near the middle; or any other direction may
be given to them, to prevent derangement by expansion.
The tubes C and a@ are kept from separating by boits from
the inside of a passing through the top of C, whcre they
are secured by nuts screwed on to them (see fig. 5.); and
these parts of C are so contrived, that by taking off any of
the nuts a cover may be removed, and a hole presented
Jarge enough to admit a man’s hand into C to clean it out.
Fig. 5 is a longitudinal vertical section of the boiler and
furnace, through the centre of the axis of the main cylin-
der A, showing the course which the flame and heated air
are forced to take. The first three small cylinders are com-
pletely surrounded with flame, being directly over the fire ;
the flame is stopped by the brick-work W over the.fifth, and
forced to pass under it, and then over the sixth, where it
again meets with an interruption, which forces it to go under
the seventh, over the eighth, and partly over partly under
the ninth, It then turns round the end of the longitudinal
wall which divides the furnace, and passes over the eighth
smaller cylinder, under the seventh, and so on alternately
over

applicable to Steam Engines, €c. 43

over and under the other tubes, till it reaches the chimney B,
fig. 4. The wall that divides the furnace may be seen in fig. 3,
N,N, and in fig. 6, at N.

To secure a free communication between the different
parts of the boiler, the three tubes of the middle cylin-
der C are connected with those of the two exterior C’s by
two pipes oo. The other ends of the tubes aaa are each
fitted with a cover properly secured and bolted, but which
can be taken off occasionally to clean out the boiler.

In working with such boilers, the water carried off by
evaporation is replaced by water forced in by the usual
means ; and the steam generated is carried to the place in-
tended, by means of tubes connected with the upper part of
the cylinder A.

Mr. Woolf has taken out a patent for this very valuable
contrivance. In the specification he has lodged of bis in-
vention, means are pointed out for applying it to the boilers
of steam-engines already in use, by ranging a row of cy-
linders below the present boiler, and connecting them with
each other and with the boiler. Directions are also given
for constructing boilers composed of cylinders disposed ver-
tically ; but as we consider such an arrangement inferior to
the horizontal, and as being introduced, perhaps, chiefly for
the purpose of preventing his patent from being infringed
by evasion, we shall not give any further description of it.
We cannot, however, dismiss this article without quoting.
some of Mr. Woolf’s remarks, which may prove very
useful.

_ © Tt may not be improper (says he) to call the attention
of those who may hereafter wish to construct such apparatus
to one circumstance, namely, that in every case the tubes
composing the boiler should be so combined and arranged,
and the furnace so constructed, as to make the fire, the flame
and heated air to act around, over and among the tubes,
embracing the largest possible quantity of their surface. It
must be obvious to any one that the tubes may be made of
any kind of metal ; but I prefer cast iron as the most con-
venient... The size of the tubes may be varied : but in every
case care should be taken not to make their diameter too
great; and it must be remembered, that the larger the dia-
meter of any single tube in such a boiler the stronger must
it be made in proportion, to enable it to bear the same ex~-
pansive force as the smaller cylinders. It is not essential,
Soweven, to my invention that the tubes should be of dif-
ferent sizes ; but I prefer that the upper cylinders, especially
the one which } call the main cylinder, should be Meaty

l ; than

44 On Mr. Arthur WVoolf’s improved Apparatus,

_ than the lower ones, it being the reservoir as it were into
which the lower ones send the steam, to be thence conveyed
away by the steam pipe or pipes.. The following general
direction may be given respecting the quantity of water to
be kept in a boiler on my construction :—it ought always to
fill not only the lower tubes, but the main cylinder A and
the cylinder C to about half their diameter; that is, as high
as the fire is allowed to reach—and in no case ought it to
be allowed to get so low as not to keep full the necks or
branches which join the smaller cylinders, marked with the
letter g, to the cylinders A or C3 for the fire is only bene-
ficially employed when applied, through the medium of the
interposed metal, to water, to convert it into steam: that
is, the purpose of my boiler would in some measure be de-~
feated, if any of the parts of the tubes exposed to the direct
action of the fire should present in their interior a surface
of steam instead of water, to receive the transmitted heat,
which must more or less be the case if the lower tubes,’
and even a part of the upper, be not kept filled with the
liquid.

«* As to the construction of the furnaces, though that.
must be obvious from the drawings, it may not be improper
here to remark that they should always be-so built as to
give a long and waving course to the flame and heated air,
or vapour, forcing them the more effectually to strike against
the sides of the tubes which compose the boiler, and so to
give out a large portion of their heat before they reach the
chimney: unless this be attended to, there will be a much
greater waste of fuel than necessary; and the heat commu-
nicated to the contents of the boiler will be less from a
given quantity of fuel.

«¢ My invettion is not only applicable to all the uses to
which the boilers in common use are generally applied, but
to all of them with much better effects. than the latter, and
can besides be applied to purposes in which boilers, con-'
structed as they have hitherto been, would be of little or no’
use. The working of all kinds of ‘steam engines is one:
important application of my invention ; for the steam may’
be raised, in a boiler constructed in the manner before de-!
scribed,-to such a temperature, and consequently to such:
an expansive force, as to work an-engine even without con.
densing the steam, by simply allowing it to escape into:
the atmosphere after it has done its office, as proposed by’
Mr. James Watt, in the specification of his patent, dated.
January 5, 1769: where he says, engines may be worked:
by the force of steam.only, by discharging the steam@into’

the

applicable to Steam Engines, @c. 45

the open air. In all cases where it is desirable to heat or
boil water, or other fluids and substances, without the di-
rect application of fire to the vessel or vessels containing
them, which in such cases become secondary boilers, the
use of my apparatus will produce effects superior to any
obtainable by other means,—no more being necessary than
to make the vessel, or secondary boiler, containing the
waier or other fluids, and the substances immersed or dis-
solved in, or blended or mixed with the water or other
fluid, to communicate, by means of a tube or tubes, with
the prime boiler, constructed in the manner before described.
In such cases, as in making extracts of every kind for the
various purposes of arts and manufactures, and for the
simple boiling of water or watery fluids, the steam should
go directly into the vessel, or secondary boiler, whose con-
tents are to be heated or boiled; and the orifice or orifices of
the pipe or pipes through which the steam is conveyed
should go toa considerable depth in the fluid, that the steam
may be the better able to give off its heat and be condensed
before it can reach the surface: and in every such case, an
allowance should be made for the increase which will be made
to the quantity of liquid in the vessel to be heated, by the
quantity of steam which will be condensed in the same be-
fore the process be ended. The vessels into which the steam
is thrown may be either open or close, as the nature of cir-
cumstances may require: but where extracts are to be made
from vegetable or other matters from which extracts are or
may be made, as from hops, bark, drags and dye-stuffs, for
brewing, tanning, dyeing and other processes, the materials
will be much more completely exhausted of all their valuable
parts ; and in many instances they will be completely dis-
solved by employing close vessels, which im that case must be
made very strong,—a thing not difficult to be accomplished,
when it is recollected that they may be at a distance from,
and consequently out of the power of being deranged by, the
fire, and that they may be surrounded with, and as it were
buried in, massy stone or brick-work, in addition to other
and obvious means of securing them. My apparatus so
employed becomes, in fact, an improved Papin’s digester
on a large scale. Ido not wish to be understood as claim-
ing the merit of having been the first who applied steam in
the manner just described to boil water and other fluids,
but merely as pointing out an important use to which my
apparatus is applicable, and in which the effect obtained

will be much greater than by any other means.
«< Another important use to which my invention can be
applied with better effect than the means now in Dae 2
; that

~

46 On Mr. Arthur Woolf’s improved Apparatus, 8c.

that of distillation on the large scale, and that by either
sending the steam directly into and among the contents of
the still or alembic, or by imclosing the still in another
vessel, and making the steam of a high temperature, to cir-
culate in and to occupy the space between the exterior sur-
face of the still and the interior surface of the containing
vessel. In either case, all danger of burning or singeing
‘the materials operated upon is done away, and a much more
pleasant and pure spirit will be obtained than by the methods
now in common use. [ need not stop here to show the
reason why, even in the case of throwing the steam directly
into the still, the spirituous part will be the first to rise and
pass over into the receiver.

*< T might mention many other useful applications that
ynay be made of my invention ; but I shall only state one
more, namely, to the drying of gunpowder, and lessening
the danger of explosions in the manufacture of that article.
By means of my invention, any desired temperature, ne-
cessary for that purpose, may be produced where the powder
is to be dried, without the necessity of having fire in, or so
near the place as to endanger its safety ; eee employing
steam only, conveyed through pipes, and properly applied
and directed, without allowing any of it to escape into the
room or apartment where the powder is, any competent
workman can produce a heat equal to that found necessary
for drying gunpowder, or much higher if required. Nor
is the lessening of the danger of explosions the only ad-
vantage which this way of drying gunpowder holds out—it
presents another and an essential one for the goodness of
the article—the heat can be completely regulated so as to
prevent, or at least lessen, the partial decomposition of the
powder by the sublimation of the sulphur, which is found
to take place by the methods at present in use.”

In every case Mr. Woolf uses two sufety valves, at least,
in his apparatus, to are accidents: a precaution which
cannot be too strongly enforced; as it may happen, when
but one is employed, it may by some accident get locked,
and the works and people about them be exposed to the
danger of an explosion.

Besides the common safety valves, Mr. Woolf has also
introduced a valve, of a new construction, into the steam-

ipe itself, to regulate the quantity that shall pass from the
Lailée. Tn fact, it is a self-acting regulator ; and being ex-
tremely ingenious, we think we shall be gratifying our
readers by laying a description of it before them, which we
shall in our next, with an accurate engraving.

The two boilers now constructing for Messrs. Meux will

not

On the Motion of Bodies affected by Friction. 47

not be the least curious part of the immense collection of in-
genious mechanism of which their premises can boast. They
are not intended for the steam engine, but to supersede the
necessity of applying fire directly to their two large boilers,
each of which are of the contents of about 800 barrels.
They are in future to be heated by steam, sent into them
from these new boilers; which will not only prevent the
wear to which the coppers are exposed by the usual practice,
which costs a large sum of money yearly, but, it is ex-
pected, will produce a large saving in fuel.

We understand also, that when these boilers are finished
Messrs. Meux mean to have one constructed for their steam
engine. Indeed, if these boilers shall. be found to answer
the purposes expected from them, and we can see no reason
to induce us to doubt of their success, it will occasion a
complete change in numerous departments of arts and
manufactures, in which steam and the heat that may be ob-
tained from it are, or may be, advantageously employed*.

VI. On the Motion of Bodies affected ly Friction. By the
Rev. SaMuEL Vince, A. M. of Cambridge. _Communi-
cated by ANTHONY SHEPHERD, D. D. P. R.S. Plumian
Professor of Astronomy and Experimental Philosophy at
Cambridget. Read Novemler 25, 1784.

Tue subject of the paper which I have now the honour
of presenting to the Royal Society, seems to be of a very
considerable importance both to the practical mechanic and
to the speculative philosopher; to the former, as a know~-
ledge of the laws and quantity of the friction of bodies in
motion upon each other will enable him at first to render
his machines more perfect, and save him in a great measure
the trouble of correcting them by trials ; and to the latter,
as those Jaws will furnish him with principles for his the-
ory, which when established by experiments will render
his conclusions applicable to the real motion of bodies upon
each other. But, however important a part of mechanics
this subject may constitute, and however, from its obvious
uses, it might haye been expected to have claimed a very
considerable attention both from the mechanic and philo-
sopher, yet it has, of all the other parts of this branch of
natural philosophy, been the most neglected. The law by

* Mr. Woolf has adopted for the door of his furnace Mr. Roberton’s
invention for consuming smoke, which we have therefore not described,
having given a ful] account of it in our eleventh volume.

4 From the Philosophical Transactions, vol, Ixxv. ict

which

48 On the Motion of Bodies affected by Friction.

which the motions of bodies are retarded by friction has
never, that { know of, been truly established. Musschen-
broek says that in niall velocities the friction varies very
nearly as the velocity, but that in great velocities the friction
increases : he has also attempted to prove that, by1 increasing
the weight of a body the friction does not 5 a s increase
exactly in the same ratio; and that the same body, if by
changing its position you change the magnitude of the sur-

face on which it moves, will “have its quantity of friction .

also changed. Helsham and Ferguson, from the same kind
of experiments, have endeavoured to prove that the friction
does not vary by changing the quantity of surface on which
the body moyes ; and the latter of these asserts that the
friction increases very nearly as the velocity; and that by
increasing the weight, the friction is increased in the same
ratio. These different conclusions induced me to repeat
their experiments, in order to see how far they were con-
elusive in respect to the principles deduced from them:
when it appeared that there was another cause operating
besides friction, which they had not attended to, and which
rendered all their deductions totally inconclusive: Of those
who have written on the theory, no one has established it
-altogether on true principles. Euler (whose theory is ex-
tremely elegant, and which, as. he has so fully considered
the subject, would have precluded the necessity of offering
any thing further, had its principles been founded on ex-
periments) supposes the friction to vary in proportion to the
velocity of the body, and its pressure upon the plane, neither
of which are true: and others, who have imagined that
friction is a uniformly retarding force (and which conjecture
will be confirmed by our experiments), have still retained
the other supposition, and therefore rendered their solutions
not at all applicable to the cases for which they were intended.
I therefore endeavoured by a set of experiments to deter-
mine,
ist. Whether friction be a uniformly retarding force.

Qdly, The quantity of friction.

sdly, H’hether the friction varies in proportion to the pres-
sure or weight.

4thly, Whether the friction be the same, on whichever of
its surfaces a body moves.

The 5 in which T was assisted by my ingenious
friend the Rey. Mr. Jones, Fellow of Trinity college, were
made with the uimost care and attention; and the several
results agreed so very exactly with each other, that I do not
somes io pronounce them to be conclusive.

g. A plane was adjusted parallel to the horizon, at the

extremity

On the Motion of Bodies affected ly Friction, 49

extremity of which was placed a pulley, which could be
elevated or depressed in order to render the string which
connected the body and the moving force parallel to the
plane. A scale accurately divided was placed by the side of-
the pulley, perpendicular to the horizon, by the side of which
the moving force descended ; upon the scale was placed a
moveable stave, which could be adjusted to the space through
which the moving force descended in any given time, which
time was measured by a well-regulated pendulum clock vi-
brating seconds. Every thing being thus prepared, the fol-
lowing experiments were made to ascertain the Jaw of fric-
tion. But let me first observe, that if friction be an uniform
force, the difference between it and the given force of the
moying power must be also uniform ; and therefore the
moving body must descend with an uniformly accelerated
velocity, and-consequently the spaces described from the
beginning of the motion must be as the squares of the times,
just as when there was no friction, only they will be dimi-
nished on account of the friction.

3. Exp. 1. A body was placed upon the horizontal plane,
and a moving force applied, which from repeated trials was
found to descend 524 inches in 4”, for by the beat of the
clock and the sound of the moving force when it arrived at
the stage, the space could be very accurately adjusted to the
time: the stage was then.removed to that point to which
the moving force would descend in 3”, upon supposition
. that the spaces described by the moving power were as the
‘gquares of the times; and the space was found to agree very

accurately with the time: the stage was then removed to
that point to which the moving force ought to descend in
2”, upon the same supposition; and the descent was found
to agree exactly with the time: lastly, the stage was adjusted
to that point to which the moving force ought to descend
in 1”, upon the same supposition; and the space was ob-
seryed to agree with the time. Now in order to find whether
a difference in the time of descent could be observed, by
removing the stage a little above and below the positions
which corresponded to the above times, the experiment was
tried, and the descent was always found too soon in the
former, and too late in the Jatter case; by which I was as-
sured that the spaces first mentioned corresponded exactly
to the times. And, for the greater certainty, each descent
was repeated eight or ten times; and every caution used in
this experiment was also made use of in all the following.

Exp. 2. A second body was laid upon the horizontal plane,

and a moving force applied which descended 413 inches in
Vou. XVII. No. 65. D } 3”:

50 ~ On the Motion of Bodies affected ly Friction.

ie the stage was died adjusted to the space corresponding

to 2”, upon supposition that the spaces descended through
were as the squares of the times ; and it was found to agree
accurately with the time : the stage was then adjusted to » the

space corresponding to 1”, upon ‘the same supposition ; and
it was found to agree with the time.

Exp. 3. A third body was laid upon the horizontal plane,
and a moving force applied, which descended 59; inches in
4”; the stage was then adjusted to the space corresponding
to 3”, upon supposition that the spaces descended through
were as the squares of the times, and it was found to agree
with the time : the stage was then adjusted to thé space cor-
responding to 2”, upon the same supposition, and it was
found to agree with the time: the stage was then adjusted
to the space corresponding to 1”, and was found’ to agree
with the time.

Exp. 4. A fourth body was then taken and Jaid upon the
horizontal plane, and a moving force applied, which de-
scended 55 inches in 4”: the stage was then adjusted to the
space through which it ought to ‘descend in 3”, upon sup-
position that the spaces descended through were as_ the
squares of the times, and it was found to_ agree with the
time : : the stage was then adjusted to the space Corresponding
to 2”, upon the same supposition, and was found to agree

_with the time: lastly, the stage was adjusted to the space
corresponding to 1”, and it was s found to agree exactly with
the time.

Besides these experiments, a great number of others were
made with hard bodies, or those whose parts so firmly co-
hered as not to be moved inter se by the friction; and in

each experiment bodies of very different degrees of friction
were chosen, and the results all agreed with those related
above: we may therefore conclude “that the friction of hard
bodies in motion is an uniformly retarding force.

Sut to determine whether the same was true for bodies’
when coyered with cloth, woollen, &c. experiments were
made in order to ascertain it; when it was found in all

cases, that the retarding force increased with the velocity ;
but, upon covering bodies with paper, the consequences
were found to agree with those related above.

4. Having proved that the retarding force of all hard
bodies arising from friction is uniform, the quantity of fric-
tion, Considered as equivalent to a weight without inertia
drawing the body on the horizontal plane backwards, or
acting “contrary to the moving force, may be immediately
deduced from the foregoing experiments, For let M=the

moving

On the Motion of, Bodies affected by Friction. 51

moving force expressed by its weight; F=the friction; W
= the w eight of the body upon the horizontal plane; S=
the space through which the moving force descended in the
time ¢ expressed i in seconds 3 7 = 16, +z feet; then the whole
accelerative force (the force ‘of gravity being unity), will be

MF
hence, by the laws of uniformly accelerated mo-

M+W Ww ;

—F Ww 55
tions -< rik? = S, conse seul Rem Saw ‘
2 ivi + \ q 24 ore
To Merk chit this, Ict us ant the case of the last po

‘pent, where M’= 7, W = 953,'S = 4 feet, ¢ =+4’
1 din 3
322 X 477 . :
1 pe oe = 6.4175 consequently the AS SR
was to the weidhrz aie

And the great “accurabe rubbing body as 6.4167 to 25.75.
method is manifest from hentermining the friction by this
had been made in the descent (ariif : an error of one inch
made may always determine the. space ements carefully
exactness), it would not have affected the concluh greater
part of the whole. .dth
5. We come in the next place to determine whcethe,
friction, ceteris paribus, varies in proportion to the w eight
or pressure. Now if the whole quantity of the friction of
a body, measured by a weight without inertia equivalent to
the friction drawing the body backwards, increases in pro-
portion to its weight, it is manifest that the retardation of

the velocity of the body arising from the friction will not
Quantity of friction ,

be altered; for the retardation varies as ;
Quantity of matter
hence, if a body be put in motion upon the horizontal plane
by any moving force, if both the weight of the body and
the mnoving force be increased in the same ratio, the acce-
Jeration arising from that moving force will remain the same ;
because the accelerative force varies as the moving force di-
vided by the whole quantity of matter, and both are In-
creased in the same ratio; and if the quantity of friction
increases also as the weight, then the retardation arising
from the friction will, from what has been said, remain the
same; and therefore the whole acceleration’ 6f the body will
not be altered: consequently the body ought, upon this
supposition, still to describe the same space in the same
time. Hence, by observing the spaces described in the same
time, when both the body and the moving force are increased
in the same ratio, we may determine whether the friction
- increases in proportion to the weight. The following ex-
D2 periments

52 On the Motion of Bodies afected by Friction.

periments were therefore made in order to ascertain this
matter.

Exp. 1. A body weighing 16 oz. by a moving force of
4 oz. described in 2 a space of 51 inches; by loading the
body with 10 oz. and the moving force with 4 02, it de-
scribed 56 inches in 2” ; and by loading the body again ‘with

10 oz. and the moving force with 4 oz. it desenbed 63
inches in 2”. :

Exp. 2. A body, whose weight was 16 02. by a moving
force of 5.02. described a space of 49 inches in 3”; and by
loading the body with 64 0z. and the moving foree with
20 oz. the space ‘described in the same time was 64.urce of

Exp. 3. A body weighing 6 oz. by a mang the body
21 oz. described 28 inches m 2”; an‘10 oz. the space de-
with 24 oz. and the moving fe4 inches.
scribed in the same timaing 8 oz. by a moving force of 4

Exp. 4. A bog-inches in 2”; and by loading the body
oz. descrikmd the moving force with 4 oz. the space de-
within the same time was 47 inches.
~ Exp. 5. A body whose weight was 9 oz. by a moving

force of 43 oz. described 48 inches in 2”; and by loading
the body with 9 oz. and the moving force with 45 oz. the
space described in the same time was 60 inches.

Exp. 6. A body weighing 10 oz. by a moving force of 3
oz. described 20 inches in 2”; by loading the body with 10
oz. and the moving force with 3 oz. the space described in
the same time was 31 inches; and by loading the bedy again
with 30 oz. and the moving force with 9 oz. the space de-
scribed was 34 inches in 2”.

From these experiments, and many others which it is not
necessary here to relate, it appears that the space described
is always increased by increasing the weight of the body
and the accelerative force in the same ratio: and as the ac-
celeration arising from the moving force continued the
same, it 1s manifest that the retardation arising from the
friction must have been diminished ; for the whole accele-
rative force must have been increased on account of the in-
crease of the space described in the same time ; and hence,

Quantity of =)
Quantity of matter
the quantity of friction increases in a less ratio than the
quantity of matter or weight of the body.

6. We come vow .to the last thing which it was proposed
to determine, that is, whether the friction varies by varying
tig surface on which the body moves. Let us call two of

the

(as the retardation from friction varies as

On the Motion of Bodies affected by Friction. 53

the surfaces A and a, the former being the greater, and the
latter the less. Now the weight on every given part of a is
as much greater than the weight on an equal part of A, as
A is ereater than a; if therefore the friction was in propor-
tion to the weight, ceteris pariius, it is manifest that the
friction on @ would be equal to the friction on A, the whole
friction being, upon such a supposition, as the weight on
any given part of each surface multiplied imto the number
of such parts, or into the whole area; which products, from
the proportion above, are equal. But from the last experi-
ments it has been proved that the friction on any given
surface increases in a less ratio than the weight; conse-
quently the friction on any g given part of a has a less ratio
to the friction on an equal part of A than A has to a3 and
hence the friction on a is less than the friction on A, that
is, the smallest surface has always the least friction. But
-as this conclusion is contrary to the generally received opi-
nion, I have thought it proper to confirm the same by a set
of experiments. But before I proceed to relate them, I
will beg leave to recommend to those, who may afterwards
be induced to repeat them, the following cautions, which
are extremely necessary to be attended to. Great care must
be taken that the two surfaces have exactly the same degree
of roughness ; 1m order to be certain of w hich, such bodies
must be chosen as have no knots in them, and whose grain
is so very regular, that when the two surfaces are planed

. ° .
with a fine rough plane their roughness may be the same,

which will not be the case if the body be knotty, or the
grain irregular, or if it happens not to run in the same di-
rection on both surfaces. _When you cannot depend on the
surfaces having the same degree of roughness, the best way
will be to paste some fine “rough paper on each surface,
which perhaps will give a more equal degree of roughness
than can be obtained by any other method. Now as the
proof which I have already given depends only on the mo-
tion of the body upon the same surface, it is not liable to
any inaccuracy of the kind which the preceding cautions
have been given to avoid, nor indeed to any other, and
therefore it must be perfectly conclusive. In the following
experiments the cautions mentioned above were carefully
attended to.

Exp. 1. A body was taken whose flat surface was to its
edge as 22 : 9, and with the same moving force the body
described on its flat side 33) inches in 2”, and on its edge
47 inches in the same time.

Exp. 2. A second body was taken whose flat surface was

D 3 to

54 On the Motion of Bodies affected ly Friction.

to its edge as 32 : 3, and with the same moving force it
described on its flat side 32 inches in 2”, and on its edge it
deseribed 37. inches in the same time.

Exe. 3 a took another body and covered one of its sur-
faces, w Hast length was g inches, with a fine rough paper,
cos by applying a moving force, it described 25 inches in

; I then took off some paper from the, middle, leaving
sit tbree-eighths of an inch at the two ends, and withthe
same moving : force it described 40 inches in a same time.

Exe. 4. Another body was taken which had one of its
surfaces, whose length was g inches, covered with a fine
rough paper, and by ‘apply’ ing a moving force it described 42
inches in 2”; some of the paper was then taken off from
the middle, leaving only 1} inches at the two ends, oo
with the same moving force it described 54 inches in 2”; I
then took off -more paper, leaving only one-fourth» of eft
inch at the two ends, and the body then descr ibed, by the
same moving force, 60 inches im the saine time.

In the two last experiments the paper w hich was taken off
the surface was laid on the body, that its weight might not
be altered.

EPs 5. HAs sme was taken whose flat surface was to its

edge as 30: 17; the flat side was laid upon the horizontal
plane, a neni force was applied, and the stage was fixed
im order to stop the moving force, in consequence of which
the body would then go on with the velocity acquired until
the friction had destroyed all its motion; when it appeared
from a mean of 12 trials that the whole body moved, after
its acceleration ceased, 5} imches before it stopped. The
edge was then applied, nee the moving force descended
through the same space, and it was found, from a mean of
the same number of trials, that the space ‘desexibed was 7}
inches before the body lost all its motion, after it ceased to
be accelerated.

Exe. 6. Another body was then taken whose flat surface
was to its edge as GO : 19, and, by proceeding as before,
on the flat sarface it described, at a mean of 12 trials, 54
inches, and on the edge 644 inches, before it stopped, after
the acceleration ceased.

Exp. 7. Another body was taken whose flat surface was
to its edge as 26 ;: 3, and the spaces described on these
two surfaces, after the acceleration ended, were, at a mean
of 10 trials, 4, and 72 inches respectively.

From all these different experiments it appears. that the
smallest surface had always the least friction, which agrees
with the consequence deduced from the consideration that

the

On the Motion of Bodies affected by Friction. 55

the friction does not increase in so creat a ratio as the weight:
we may therefore conclude that éhe friction of a body does
not continue the same when it has different surfaces applied
to the plane on which it moves, but that the smallest surface
will have the least friction.
7. Having thus established, from the most decisive ex-
periments, -all that I proposed relative to friction, I think
it proper, before I conclude, to give the result of my ex-
amination into the nature of the experiments which have
been made by others ; which were repeated in order to see
how far they were conclusive in respect to the principles
which have been deduced from them. The experiments
which have been made by all the authors that I have seen
have been thus instituted. —To find what moving force would
just put a body at rest in motion: and they concluded from
thence, that the accelerative force was then equal to the
friction; but it is manifest that any force which will put
a body in motion must be greater than the force which op-
poses its motion, otherwise it could not overcome it; and
hence, if there were no other objection than this, it is evi-
dent that the friction could not be very accurately obtained :
but there is another objection which totally destroys the ex-
periment so far as it tends to show the quantity of friction,
which is the strong cohesion of the body to the plane when
it lies at rest; and this is confirmed by the following ex-
periments. ist, A body of 123 0z. was laid upon an hori-
zontal plane, and then loaded with a weight of 8 lb. and
such a moving force was applied as would, when the body
Was just put In motion, continue that motion without any
aeceieration, in which case the friction must be just equal
to the accelerative force. The body was then stopped; when
it appeared that the same moving force which had kept the
body in motion before would not put it in motion, and it was
found necessary to take off 44 oz. from the body before the
same moving force would put it m motion: it appears,
therefore, that this body, when laid upon the plane at rest,
acquired a very strong cohesion to it. 2dly, A body whose
weight was 16 oz. was laid at rest upon the horizontal plane,
and it was found that a moving force of 6 oz. would just
put it in motion; but that a moving force of 4 oz. would,
when it was just put in motion, continue that motion with-
out any acceleration, and therefore the accelerative force
must then haye been equal to the friction, and not when
the inoving force of 6 oz. was applied.
lrom these experiments thercfore it appears, how very
my Dive con-
I

56 On the Motion of Bodies affected by Friction.

considerable the cohesion was in proportion to the friction,
when the body was in motion; it being, in the latter case,
almost one-third, and in the former it was found to be very
“nearly equal to the whole friction. All the conclusions,
therefore, deduced from the experiments which have been
instituted to determine the friction from the force necessary
to put a body in motion (and I have never seen any described
but upon such a principle), have manifestly been totally
false ; as such experiments only show the resistance which
arises from the cohesion and friction conjointly.

8. I shall conclude this part of the subject with a remark
upon Art. 5. It appears from all the experiments which I
have made, that the proportion of the increase of the fric-
tion to the increase of the weight was different in all the
different bodies which were made use of: no general rule
therefore can be established to determine this for all bodies s
and the experiments which I have hitherto made have not:
been suflicient to determine it for the same body. At some
future opportunity, when I have more Icisure, I intend to
repeat the experiments in order to establish, in some par-
ticular cases, the law by which the quantity of friction in-
creases by increasing the weight. Leaving this subject,
therefore, for the present, I shall proceed to establish a the-
ory upon the principles which we have already deduced from
Our experiments.

PROPOSITION I.

_ Lete, f, g, (fig. 1. Plate If.) represent either a cylinder,
or that circular section of a body on which it rolls down the
inclined plane CA, in consequence of its friction, to find the
time of descent and the number of revolutions.

As it has been proved in Art. 5. that the friction of a
body does not increase in proportion to its weight or pres-
sure, we cannot, therefore, by knowing the friction on any
other plane, determine the friction on CA; the friction
therefore on CA can only be determined by experiments
made upon ¢hat plane, that is, by letting the body descend
fromi rest, and observing the space described in the first
second of time: call that space a, and then, as by Art. 3.
friction is an uniformly retarding force, the body must be
uniformly accelerated, and consequently the whole time of
=. Now to determine

descent in seconds will be =

the number of revolutions, let s be the center of oscillation
to

On the Motion of Bodies affected by Friction. 57

to the point of suspension a*; then, because no force
acting at @ can affect the motion of the point s, that point,
notwithstanding the action of the friction at a, will always
have a motion parallel to CA uniformly accelerated by a
force equal to that with which the body would be accelerated
if it had no friction; hence, if 2m= 32¢ feet, the velo-
city acquired by the point sin the first second will be =
2mxCB,
; >
that of r (r being the center) is manifestly the velocity with
which s is carried about 7 ; hence the velocity of s about

now the excess of the velocity of the point s above

2mxCB 2m x CB—2axCA
the center = ——_—- —2a= consequent!
CA CA ie Ics SOA
gee 2mxCB—2axCA | 2m xraxCB—2axraXCA

CA Tyee Vile ee on

= the velocity with which a point of the circumference 18
carried about the center, and which therefore expresses the
force which accelerates the rotation ; now as 2a expresses
the accelerative force of the body down the plane, and the
spaces described in the same time are in proportion to those
2mKraxCB—2axraXKCA

ESOS

forces, we have 2a : CA ::

SAr ence a the space which any point of the
aARKrs

circumference describes about the center in the whole time
of the body’s descent down CA ; which being divided by
the circumference p x 7 @ (where p= 6.283, &c.) will
mXBC—aXAC
pKaxrs

give for the whole number of revolutions
required.

Cor. 1. If ax CA =m x BC, the number of revolu-
tions = 0, and therefore the body will then only slide;
consequently the friction vanishes.

Cor.2. Let a'r’ s’ (fig. 2.) be the next position of ars,
and draw tr’ d parallel to sa, then will st represent the
retardation of the center 7 arising from friction, and ab
will represent the acceleration of a point of the circumfe-
rence about its center; hence the retardation of the center :
acceleration of the circumference about the center :: sé :
al :: (by sim. A’s) tr’: br s: rs ra.

Cor. 3. If d coincides with a, the body does not slide,
but only roll; now in this case ss’ : ry” i: as : a7; but

,
* aand s are not fixed points in the body, but the former always re-
presents that point of the body in contact with the plane, and the latter

the corresponding center of oscillation,
as

58 Oliservations on the Processes of Tanning.

as ss’ and 1?” represent the ratio of the velocities of the

points s and r, they will be to each other as ux : 2a

or as m x CB: ax CA; hence, when the oe rolls
without sliding, as : ar :i mx CB: ax CA.

Cor. 4. The time of descent down CA is = A But

by the last Cor. when the body rod/s without sliding, a=
mer ax KC ic
sax RGU

fa

m X aXBe

, hence the time of descent in that case = AC
; now the time of descent, if there were no

friction, would be = Wee Te hence the time of descent,

Xu

when the body rods without sliding : time of free descent
t: Vsa: ./ra.

Cor. 5. By the last Cor. it appears, that when the body
just rolls without sliding,.or when the friction is just
equal to the accelerative force, the time of descent = AC
ot iT, ag now it is manifest that the time of descent

Km aK BCI :
will continue the same, if the friction be increased; for the
body will still freely roll, as no increase of the fric fon acting
at a can affect the motion of the point s.

If the body be projected from C with a velocity, and at
the same time have a rotatory motion, the time of descent
and the number of revolutions may be determined from the
common principles of uniformly ‘accelerated motions. As
we have already investigated the accclerative force of the
body down the plane, and of its rotation about its axis, it
seems therefore unnecessary to lengthen out this paper w ith

the investigations.
[ To be continued. }

VIE. Observations on the Processes of Tanning: By Uom-
pury Davy, Esq., Professor of Chemistry in the Royal
Institution, ~

{Concluded from our last volume, p. 85. ]

¥. On the Impregnation of Skin with the Tanning Principle.
ren
ue tanning lixivium or ooze is generally made in this
country, by infusing braised or coarsely’ powdered oak bark
in water,
Skins are tanned by being successively immersed in lixi-
: i ; yiuils,

Oliservations on the Processes of Tanning. 59

viums, saturated in different degrees with the astringent
principles of the bark. The lixiviums first employed are
usually weak; but for the completion of the process they
are made as strong as possible.

In the process of tanning, the skin gains new chemical
properties; it inereases in weight, and becomes insoluble in
boiling water.

The infusions of oak bark, when chemically examined,
are found to contain two principal substances; one is pre-
eipitable by solution of gelatine, made from glue or isin-
glass; and gives a dense black with solution of common
sulphate of iron. The other is not thrown down by solu-
tion of gelatine; but it precipitates the salts of iron of a
brownish black, and the salts of tin of a fawn colour.

The substance precipitable by solution of gelatine is the
tanning principle, or the tannin of: Seguin. It is essential
to the conversion of skin into leather, and in the process of
tanning it enters into chemical union with the matter of
skin, so as to form with it an insoluble compound. The
other substance, the substance not precipitable by gelatine,
is the colouring or extractive matter; it 1s capable of enter-
ing into union with skin, and it gives to it a brown colour;
but it does not render it insoluble in boiling water.

It has been usually supposed that the infusion of oak bark
contains a peculiar acid, called gallic acid; but some late
experiments render this opinion doubtful: and this prin-
ciple, if it exists in oak bark, is in intimate combination
with the extractive or colouring matter.

In the common process of tanning, the skin, which is
chiefly composed of gelatine, slowly combines in its or-
ganized form with the tannin and extractive matter of the
infusions of bark; the greater proportion of its increase of
weight is however owing to tannin, and it is from this sub-
stance the leather derives its characteristic properties ; but
its colour, and the degree of its flexibility, appear to be in-
fluenced by the quantity of colouring matter that it contains.

When skin, in large quantity, is suffered to exert its full
action upon a small portion of infusion of bark, containing
tannin and extractive matter, the fluid is found colourless.
it gives no precipitate to solution of glue, and produces very
little effect upon the salts of iron, or of tin.

The tanning principle of oak bark is more soluble in
water than the extractive matter: and the relative propor-
tion of tannin to extractive matter is much greater in strong
infusions of oak hark than in weak ones ; and when strong
) infusions

60 Olservations on the Processes of Tanning.

infusions are used for tanning, a larger proportion of tan-
nin is combined with the matter of skin.

For calf skins, and light. cow skins, which are usuaily
prepared 1 in the grainer, w weak lixiviums are used in the first
part of the process; but thick ox hides, for the purpose of
stout sole leather, are generally kept in a strong 002e, pre-
served constantly in a state approaching to saturation, by
means of strata of bark

Calf skins, and light cow skins, in the usual process,
require for their full: impregnation with tannin from two
to four months; but thick ox hides demand from ten to
eighteen months. F

“In any case the state of the skin with regard to impreg-
nation with tannin may be easily judged of, if it be cut
transversely with a sharp knife: in this case the tanned
part appears of a nutmeg colour ; but the unimpregnated
skin retains its whiteness.

The tanned hides designed for sole leather, are, v while
drying, generally smoothed with a stout steel pin, and beat
with a mallet. By this process they are rendered denser,
firmer, and less permeable to water: calf skins are not sub-
jected to the operation of beating; and they are treated in
different ways by the currier, according as they are needed
for different purposes.

III. General Remarks relating to the Processes of Tanning.

A very great number of vegetable productions, besides
oak bark, contain the principle essential to the conversion of
skin into leather: galls, sumach, the bark of the Spanish
chesnut, of the elm, of the commion willow, and of the Lei-
cester willow, the branches of the myrtle, tormentil, and
heath, have all been used in the processes of tanning.

Different methods have been proposed for estimating the
quantity of tannin in different vegetable productions. Pane
nin, by being dissolved in water, increases its specific gravi-
ty, and the “hy drometer has been used for estimating the
strength of the tanning ooze. The results given by this in-
strument are, however, often fallacious in comparative ex-
periments, in consequence of the presence of extractive
matter, and of saline substances; and the action of the so-
lution of gelatine affords the best indication of the quantity
of the tanning principle.

The solution of gelatine most proper for the general pur-
poses of experiments, is made by dissolving an ounce of
glue, or of isinglass, in three pints of boiling \ water.

The:

Observations on the Processes of Tanning. 61

The substance to be examined as to its tanning ha
may be used in the quantity of two ounces ; It a re 7.
a state of coarse powder, or In small fragments: quart o

re 5 ae aissolye its astringent
boiling water will be sufficient to “5° g
principles.

oe « egie, OF gelatine, must be poured into the
he solutionsion, till the effect of precipitation is at an end.
astTye turbid liquor must then be passed through a piece of
blotting-paper, which has been before weighed.

When the precipitate has been collected, and the paper
dried, the increase of its weight is determined ; and about 2
of this increase of weight may be taken as the quantity of
tannin in the ounce of the substance examined.

When solution of gelatine cannot be obtained, a solution
of albumen may be used. It is made by agitating the white
of an ege in apint of cold water. It does not putrefy nearly
so readily as the solution of glue, and it may be employed
with equal advantage in experiments of comparison ; but the
composition of the precipitates it forms with tannin, has
not as yet been ascertained.

The tanning principle in different vegetables is possessed
of the same general characters; but it often exists in them
in states of combination with other substances.

In galls it is in union with the gallic acid. In sumach it
is mixed with saline matter, particularly sulphate of lime ;
and in the greater number of barks it is in combination with
mucilage, and different extractive and colouring matters.

Leather tanned by means of different astringent infu-
sions, differs considerably in its composition ; but it seldom
contains more than 1-8d of its weight of vegetable matter.

Gallic acid, and saline matters in general, m cases when
they are combined with tannin, are not absorbed with it by
skin; but they remain in their primitive forms.

The leather made from infusions of Aleppo galls, and
of sumach, is composed probably of pure tannin and the
matter of skin. Its colour is very: pale, and the increase of
weight is greater than in most other cases.

Extractive, or colouring matters, in cases when they exist
in astringent infusions, as in the instance of oak bark al-
ready mentioned, are wholly or partly absorbed with the
tannin by the skin. The leather from barks im general is
coloured, and contains different proportious of extractive
matter. .

Of all the substances that have been examined as to their
tanning properties, catechu or terra japonica, is that which
is richest in the tanning principle. This substance is the

3 extract

62 Observations on the Processes of Tanning.

extract of the wood of a
abundantly in India ;
the quantitice jy whic
reason to believe visy
commerce.

In a paper published in the Phuc. .;; iT
for 1803 *, a statement is given of the comipa. Transactions,
different astringent substances, oak bark being “oyalue of
as the standard. m5

The attraction of tannin for water is much stronger than
that of any other of the principles usually found in astrin-
gent vegetables ; and the saturated infusions obtained from
substances containing very different proportions of astrin-
gent matters, are usually possessed of the same degree of
stre1 neth with regard to their tanning powers.

When saturated solutions of the tanning principle are
used in the process of manufacture, the leather is tanned in
a much shorter time than in the common operation with
weaker infusions. The rapid method of tanning has been
recommended by Mr. Seguin; and is ably described, in a
pamphlet published by Mr. Desmond.

It has however been generally observed, that leather too
quickly tanned is more rigid, and more liable to crack than
leather slowly tanned. And there is every reason to be-
lieve that its texture must be less equable, as the exterior
strata of skin would be perfectly combined with tannin be-
fore the interior strata were materially acted upon; and the
want of colouring or extractive matter in the strongest lixi-
vium, in many cases must affect the nature of the leather.

The substances used for tanning should, in all cases, be
preserved in as dry a state as possible before they are used.
When they are exposed to moisture and air, the tanning
principle by degrees is destroyed in them, and for the most
part converted 1 into insoluble matter.

The process of drying bark by heat, when carefully con-
ducted, must, as there is great reason to believe, on the
whole be advantageous. The tanning principle is not de-
composed at a temperature below 400°. And in fresh ve-
getable substances, tannin appears to be sometimes develop-
ed or formed by aie long application of a low heat: this
fact I observed with my frend Mr. Poole in September
1802, with regard to acorns; and I have since made the
sami¢ remark upon the horse chesnut.

species of the mimosa, which grows
and calculating on. its price, and on
*h it may be procured, there is great
it may be made a valuable article of

* See our next articl:.

VII. An

dine:

[ 63 }

VIII. An Account of some Experiments and Olservations
on the constituent Parts of certain astringent Vegetables ;
and on their Operation in Tanning. By Humpury Davy,
Esq., Professor of Chemistry in the Royal Institution.*

Tue discovery made by M. Seguin, of a peculiar vegetable
maiter which is essential to the tanning of skin, and which
is possessed of the property of precipitating gelatine from
its solutions, has added considerably to our knowledge of the
constituent parts of astringent vegetables.

Mr. Proust has investigated many of the properties of
this substance ; but though his labours, and those of other
chemists, have Jed to various interesting observations, yet
they are far from having exhausted the subject. The affi-
nities of tannin have been hitherto very little examined ;
and the manner in which its action upon animal matters is
modified by combination with other substances, has been
scarcely at al] studied.

At the desire of the managers of the Royal Institution, I
began, in September 1801, a series of experiments on the
substances employed in the process of tanning, and on the
chemical agencies concerned in it. These experiments have
occupied, ever since, a considerable portion of my leisure
hours; and I now presume to lay before the Royal Society
an account of their general results. My chief design was, to’
attempt to elucidate the practical part of the art: but in pur-
suing it, 1 was necessarily led to general chemical inquiries,
concerning the analysis of the different vegetable substances
containing tannin, and their peculiar properties.

I. Observations on the Analysis of astringent Vegetable
Infusions.

The substances that have been supposed to exist most ge~
nerally in astringent infusions are, tannin, gallic acid, and

extractive matter.

The presence of tannin in an infusion, is denoted by the
precipitate it forms with the solution of glue or of isinglass.
And, when this principle is wholly separated, if the remain-
ing liquor gives a dark colour with the oxygenated salts of
iron, and an immediate precipitate with the solutions of
alum and of muriate of tin, it is believed to contain gallic
acid and extractive matter. L

The experiments of MM. Fourcroy, Vauguelin, and Se-

* From Philosophical Transactions for 1803. ,
guin,

64 Experiments and Observations on the

guin, have shown that many asiringent solutions underge
a change by exposure to the atmosphere ; an insoluble mat-
ter being precipitated from them. A precipitation is like-
wise occasioned in them by the action of heat; and these
circumstances render it extremely difficult to ascertain, with
any degree of precision, the quantities of their constituent
parts, as they exist in the primitive combination.

After trying several experiments on different methods of
ascertaining the quantity of tannin in astringent infusions,
{ was induced to employ the common process of precipita-
tion by gelatine, as being the most accurate.

This process, however, requires many precautions. The
tanning principle in different vegetables, as will be seen
hereafier, demands for its saturation different proportions
of gelatine; and the quantity of the precipitate obtained
by filtration is not-always exactly proportional to the quan-
tities of tannin and gelatine im.solutions, but is influenced
by the degree of their concentrations Thus I found that
10 grains of dry isinglass, dissolved in two ounees of di-
stilled water, gave, with solution of galls in excess, a pre-
cipitate weighing, when dry, 17 grams; whilst the same
quantity, dissolved in six ounces of water, produced, all
other circumstances being similar, not quite 15 grains.
With more diluted solutions, the loss was still greater ;
and analogous effects took place, when equal portions of
the same solution of isinglass were acted on by equal por-
tions of the same infusion of galls diluted in different de-
grees with water; the least quantity of precipitate being
always produced by the least concentrated liquor. In.all
cases, when the weak solutions were used, it was observed
that the residual fluid, though passed two or three times
through the filter, still remained more or less turbid and
opaque ; so that it is most likely that the deficiency arose
from the continued suspension of some of the minutely di-
vided solid matter in the liquid mass,

The solutions of gelatine, for the purposes of analysis,
should be employed only when quite fresh, and in as high
a state of saturation as is compatible with their perfect flu-
idity. 1 have observed that, in cases when they approach
towards the state of jelly, their power of acting upon tannin
is materially altered, and they produce only a very slight
precipitation. As the degree of fluidity of solutions of ge-
latine is influenced by their temperature, I have found it
expedient, in all comparative experiments, to bring them,
and the astringent infusions on which they are designed to
act, as nearly as possible to a common degree of heat. My

. standard

constituent Parts of astringent Vegetables. 0s

standard temperature has’ been between 60° and 70° Fah-’
renheit ; and the solutions of gelatine that [have used were
made by dissolving 120 grains of isinglass in 20 ounces of
water.

In ascertaining the proportions of tannin in astringent
infusions, great care must be taken to prevent the presence
of any excess of gelatine; for when this excess exists, I
have found that.a small portion of the solid compound
formed is redissolved, and the results of the experiment
otherwise affected. It is not difficult to discover the precise
point of saturation, if the solution of isinglass be added only

- in small quantities at a time, and if portions of the clear

liquor be passed through a filter at different periods of the

i process: The properties of these portions will indicate the

quantities of the solution of gelatine required for the com-
pletion of the experiment.

That the composition of any precipitate containing tan-
nin and gelatine may be known with a tolerable degree of
precision, it is necessary that the isinglass employed in the
solution; and the new compound formed, be broucht as
nearly as possible to the same degree of dryness. For this
purpose I have generally exposed them, for an equal time,
upon the lower plate of a sand-bath, which was seldom.
heated to more than 150°. This miethod I have found much
better than that of drying at the temperatures of the atmo-
sphere, as the different states of the air, with regard to
moisture, materially influence the results.

Mr. Hatchett has noticed, in his excellent paper on Zoo-
phytes, &c.*, that isinglass is almost wholly composed of
gelatine. I have found that 100 grains of good and dry isin-
glass contain rather more than 98 grains of matter soluble in
water. So that when the quantity of isinglass, in any so-
lution employed for acting upon an astringent infusion, is
compared with the quantity of the precipitate obtained, the
difference between them will indicate the proportion of tan-
nin, as it exists in the.combination.

After the tannin has ‘been separated from an astringent
infusion, for the purpose of ascertaining its other compo-
nent parts, [have been accustomed to evaporate the resi-
dual liquor very slowly, at a temperature below 200°f; In

. . this.

* Philosophical Transactions for 1800, p. 327.

+ M. Deyenx has shown (Ainales de Chimie, tome xvii. p. 36), that in
the process of evaporating solutions of galls, no gallic acid is carried over
by the water at a temperature. below that of ebuilition. Many astyin=

ent infusions, however, lose a portion of their aromatic principle even
in casés when they are not made to boil; but this substance, though evi-

VoL XVII. No. 65. E , dent

6s Experiments and Observations on the

this process, if it contains extractive matter, that substance
is in part rendered insoluble, so as to tall to the bottom of
the vessel. When the fluid is reduced to a, thick consist-
ence, I pour alcohol upon it. If any gallic acid or soluble
extractive matier be present, they will be dissolved, after a
little agitation, in the alcohol; whilst the mucilage, if any
exist, will remain unaltered, and may be separated from the
insoluble extract by lixiviation with water.

‘I have made many experiments with the hope of disco-
vering a method by which the respective quantities of gallic
acid and extractive matter, when they exist in solution in
the alcohol, may be ascertained, but without obtaining suc-
cess in the results. It is impossible to render the whole of
any quantity of extractive matter insoluble by exposure to
heat and air, without at the same time decomposing a por-
tion of the ga'lic acid. That acid cannot be sublimed with-
out being in part destroyed; and, at the temperature of its
sublimation, extractive matter is wholly converted into new
products.

Ether dissolves gallic acid ; but it has comparatively little
action upon extractive matter. I have been able, in exa-
mining solutions of galls, to separate a portion of gallic
acid by means of ether. But when the extractive matter
is in large quantities, this method does not succeed, as, in
consequence of that affinity which is connected with mass*,
the greatest part of the acid continues to adhere to the ex-
tract.

Alumine has a strong attraction for extractive matter, but
comparatively a weak one for gallic acidf. When car-
bonate of alumine is boiled for some time with a solution
containing extractive matter, the extractive matter is wholly
taken up by the earth, with which it forms an insoluble
compound; but into this compound some of the gallic
acid appears likewise to enter; and the portion remaining
dissolved in the solution is always combined with alumine.

I have not, in any instance, been able to separate gallic
acid and extractive matter perfectly from each other; but I
have generally endeavoured to form some judgment con-
cerning their relative proportions, by means of the action
of the salts of alumine and the oxygenated salts of iron.
‘Muriate of alumine precipitates much of the extractive
cent to the smell, in the water that comes over, cannot be detected by
chemical reagents.

© See Bertholiet, Récherches suv les Lois del Affinité. Mem. de !' Ins
stitute National, tome ii. p. -

+ See Fiedler, ‘Journal de Chimie, par J. B, Van Mons, tome i. p. 5¢-
4 matter

constituent Parts of astringent Vegetables. 67

matter from solutions, without acting materially upon gallic
acid; and, after this precipitation, some idea may be formed
concerning the quantity of the gallic acid by the colour it
gives with the oxygenated sulphate of iron. In this pro
cess, however, great care must be taken not to add the so-
lution of the sulphate of iron in excess; for in this case
the black precipitate formed with the gallic acid will be re-
dissolved, and a clear olive-coloured fluid only will be ob-
tained.

The saline matters in astringent infusions adhere so
strongly to the vegetable principles, that it is impossible
to ascertain their nature, with any degree of accuracy, by
means of common reagents. By incineration of the pro-
ducts obtained from the evaporation of astringent infusions,
I have usually procured carbonate of Jime and carbonate of
potash.

In the different analyses, as will be seen from the results
given in the following sections, I have attended chiefly to
the proportions of the tanning principle, and of the prin-
ciples precipitable by the salts of iron, as being most con-
nected with practical applications.

With regard to the knowledge of the nature of the dif-
ferent substances, as they exist in the primitive astringent
infusion, we can gain, by our artificial methods of exa-
mination, only very imperfect approximations. In acting
upon them by reagents we probably; im many cases, alter
their nature ; and very few of them only can be obtained in
an-uncombined state: The comparison, however, of the
products of different experiments with each other is always
connected with some useful conclusions; and the accumu-
Jation of facts with regard to the subject must finally tend
to elucidate this obscure but most interesting part of che-
mistry.

II. Experiments on the Infusions of Galls.

I have been very much assistedsin my inquiries concern-
ing the properties of the infusions of galls, by the able me~
moir of M. Deyeux on Galls*.

The strongest infusion of galls that I could obtain at 56°
Fahrenheit, by repeatedly pouring distilled water upon the
best Aleppo galls broken into small pieces, and suffering it
to remain in contact with them till the saturation was com-
plete, was of the specific gravity 1068. Four hundred
grains of it produced, by evaporation at a temperature be-

* dnnales de Chimie, ome xvii. p. i
~

a

low

68 Experiments and Observations on the

low 200°, fifty-three grains of solid matter ; which, as well
as I could estimate by the methods of analysis that have
been just described, consisted of about nine-tenths of tan-
nin, or matter precipitable by gelatine, and one-tenth of
gallic acid, united to a minute portion of extractive matter.

100 grains of the solid matter obtained from the infusion
left, after incineration, nearly 43 grains of ashes; which
were chiefly calcareous matter, mixed with a small portion
of fixed alkali. The infusion strongly reddened paper tinged
with litmus. It was semitransparent, and of a yellowish-
brown colour. Its taste was highly astringent.

When sulphuric acid was poured into the infusion a dense
whitish precipitate was produced ; and this effect was con-
stant, whatever quantity of the acid was used. The residual
liquor, when passed through the filter, was found of a shade
of colour deeper than before. It precipitated gelatine, and,
gave a dark colour with the oxygenated sulphate of iron,

The solid matter remaining on the filter slightly reddened
vegetable blues ; and, when dissolved in warm water, co-
piously precipitated the solutions of isinglass. M. Proust*,
who first paid attention to its properties, supposes that it is
a compound of the acid with tannin: but I suspect that it
also contains gallic acid, and probably a small portion of
extractive matter. This last substance, as is well known,
is thrown down from its solutions by sulphuric acid; and
I found, in distilling the precipitate from galls by sulphuric
acid, at a heat above 212°, that a fluid came over of a light-
vellow colour, which was rendered black by oxygenated
sulphate of iron, but which was not altered by gelatine.

Muriatic acid produced, in the infusion, effects analogous
to those produced by sulphuric acid; and two compounds
of the acid and the vegetable substances were formed: the
one united to excess of acid, which remained in solution ;
. the other containing a considerable quantity of. tannin,
which was precipitated in the solid form.

When concentrated nitric acid was made to act upon the
infusion, it was rendered turbid ; but the solid matter formed
was inumediately dissolved with effervescence, and the liquor
then became clear, and of an orange colour. On examining
it, it was found that both the tannin and the gallic acid
were destroyed; for it gave no precipitate either with gela-
tine or the salts of iron, ‘even after the residual nitric acid
was saturated by an alkali. By evaporation of a portion of

** The fact of the precipitation of the solution of galls by acids was
noticed by M. Dizé: See Annales de Chimie, tome Xxxy. Pp» 37+

the

constituent Parts of astringent Vegetables. 69

‘the fluid a soft substance was obtained, of a yellowish-
brown colour, and of a slightly sourish taste. It was soluble
in water, and precipitated the nitro-muriate of tin, and the
nitrate of alumine; so that'its properties approached to
those of extractive matter; and it probably contained oxalic
acid, as it rendered turbid a solution of muriate of lime.

When a very weak solution of nitric acid was mixed with
the infusion, a permanent precipitate was formed; and the
residual liquor, examined by the solution of gelatine, was
found to contain tannin.

A solution of pure potash was poured into a portion of
the infusion. At first a faint turbid appearance was per-
ceived; but by agitation the fluid became clear, and its
colour changed from ‘yellow-brown to brown-red; and this
last tint was most vivid on the surface, where the solution
was exposed to the atmosphere. The solution of isinglass
did not act upon the infusion modified by the alkali till an
acid was added in excess, when a copious precipitation was
occasioned.

The compound of potash and solution of galls, when eva~
porated, appeared in the form of an olive-coloured mass,
which had a faint alkaline taste, and which slowly deli-
queseed when exposed to the air.

Soda acted upon the infusion in the same manner as pot-
ash; and a fluid was formed of a red-brown colour, which
gave no precipitate to gelatine.

Solution of ammonia produced the same colour as potash
and soda, and formed so perfect an union with the tannin
of the infusion that it was not acted upon by gelatine,
When the compound liquor was exposed to the heat of
boiling water, a part of the ammonia flew off, and another
part reacted upon the infusion so as to effect a material
change in its properties. A considerable quantity of inso-
luble matter was formed, and the remaining liquor con-
tained little tannin and gallic acid, but a considerable por-
tion of a substance that precipitated muriate of tin and the
salts of alumine. ,

When the experiment on the ebullition of the compound
of the infusion and ammonia was made in close vessels, the
Jiquor that came over was strongly impregnated with am-
monia; its colour was light yellow, and, when saturated
with an acid, it was very little altered by the salts of iron.
The residual fluid after the process had been conti:med for
some time, as in the other case, precipitated gelatine slightly,
but the salts of alumine copiously ; and it gaye a tinge of
red to litmus paper, ;

E3 When

jo Experiments and Olservations on the

When solution of lime, of strontia, or of barytes, was
oured in excess into a portion of the infusion, a copious
olive-coloured precipitate was formed, and the solution be-
came almost clear, and of a reddish tint. In this case the
tannin, the gallic acid, and the extractive matter, seemed
to be almost wholly carried down in the precipitates ; as the
residual fluids, when saturated by an acid, gave no precipi~
tate to gelatine, and only a very slight tint of purple to oxy-
genated sulphate of iron. 2

When the solutions of the alkaline earths were used only
in small quantities, the infusion being in excess, a smaller
quantity of precipitate was formed, and the residual Lquor
was of an olive-green colour; the tint being darkest in the
experiment with the barytes, and lightest in that with the
lime. This fluid, when examined, was found to hold in
solution a compound of gallic acid and alkaline earth. It
became turbid when acted on by a little sulphuric acid ;
and, after being filtrated, gave a black colour with the solu-
tions of iron, but was not acted upon by gelatine.

When a large proportion of lime was heated for some
time with the infusion, it combined with all its constituent
principles, and gave, by washing, a fluid which had the
taste of lime water, and which held in solution only a very
small quantity ef vegetable matter, Its colour was pale
yellow ; and, when saturated with muriatic acid, it did not
precipitate gelatine, and gave only a slight purple tinge to
the solutions of the salts af iron. The lime in combination
with the solid matter of the infusion was of a fawn colour.
It became green at its surface, where it was exposed to the
air; and, when washed with large quanties of water, it-con-
tinued to give, even to the last portions, a pale yellow tinge.

Magnesia was boiled in one portion of the infusion for a
few hours ; and mixed in excess with another portion, which
was suffered to remain cold. In both cases a deep green
fluid was obtained, which precipitated the salts of iron but
not the solutions of gelatine ; and the magnesia had acquired
a grayish-green tint. Water poured upon it became green,
and acquired the properties of the fluid at first obtaimed.
After long washing the colour of the magnesia changed ta
dirty yellow; and the Jast portions of water made to act
upon it were pale yellow, and altered very little the solu-
tions of iron.

When the magnesia was dissolved in muriatic acid, a
brownish and gurbid fluid was obtained, which precipitated
gelatine and the oxygenated salts of iron. So that there is
every reason to believe that the earth, in acting on the

; astringent

constituent Parts of astringent Vegetables. 71

astringent infusion, had formed two combinations; one
containing chiefly gallic acid, which was easily soluble in
water; the other containing chiefly tannin, which was very
difficultly soluble.

Alumine boiled with the infusion became yellowish-gray,
and gave a clear white fluid, which produced only a tinge
of light purple in the solutions of iron. When the earth *
was employed in a very small quantity, however, it formed
an insoluble compound only with the tannin and the ex-
tract, and the residual liquor was found te contain a gal
late of alumine with excess of acid.

The oxides of tin and of zinc, obtained by nitric acid,
were boiled with separate portions of the infusion for two
hours. In both cases a clear fluid, which appeared to be
pure water, was obtamed; and the oxides gamed a tint of
dull yellow. A part of each of them was dissolved in mus
riatic acid. The solution obtained was yellow ; it copiously
precipitated gelatine, and gave a dense black with the salts
of iron. Mir. Proust +t, who first observed the action of
oxide of tin upon astringent infusions, supposes that pors
tions of tannin and gallic acid are decomposed in the pro*
cess, or converted, by the oxygen of the oxide, into. new
substances. These experiments do not, however, appeat
to confirm the supposition.

M. Deyeux observed that a copious precipitation was
occasioned in infusion of galls, by solutions of the alkalis
combined with carbonic acid. Mr. Proust has supposed
that the solid matter formed is pure tannin, separated from
its solution by the stronger affinity of the alkali for water ;
and he recommends the process as a method of obtaining
tannin.

In examining the precipitate obtained by carbonate of
potash fully combined with carbonic acid, and used to sa+
turation, I have not been able to recognise in it the proper
ties which are usually ascribed to tannin: it is not possessed
of the astringent taste, and it is but slightly soluble in cold
water or in alcohol. Its solution acts very little upon ge-
Jatine, till it is saturated with an acid; and it is not posses*
sed of the property of tanning skin,

In various cases in which the greatest care was taken to
use no excess, either of the astringent infusion or of the
alkaline solution, I have found the solid matter obtained
possessed of analovous properties ; and it has always given,

* Mr. Fiedler, L believe, first observed the action of alumine upon
tannin, —Van Mon’s Journal, vol, i. p. $6.

+ danales de Chimie, tome ee 69.

4

hy

72 - Eaperiments and Observations on the

by incineration, a considerable portion of carbonate of pot-
_ash, and a simall quantity of carbonate of lime.

_ The fluid remaining after the separation of the precipi-
‘tate was of a dark brown colour, and became green at the
suriace when it was exposed to the air. It gave no preci-
pitate to solution of gelatine, and afforded only an olive-
coloured precipitate with the salts of iron,

. When muriatic acid was poured into the clear fluid, a
violent ‘effervescence was produced; the fluid became tur-
-bid ; a precipitate was deposited; and the residual liquor
acted upon gelatine and the salts of iron in a manner si-
milar to the primitive infusion.

M. Deyeux, in distilling the precipitate from infusion
of galls by carbonate of potash, obtained erystals of galli¢
acid. In following his process, I had similar results; and
.a fluid came over which reddened litmus paper, and pre-
cipitated the salts of iron black, but did not act upon gela-

tine.

» When the precipitate by carbonate of potash was acted
upon by warm water, applied in large quantities, a consi-
derable portion of it was dissolved; but a. part remained
which could not in any way be made to enter into solution,
and iis properti¢s were yery different from those of the en-
tire precipitate. It was not at all affected by alcohol: it
was acted on by muriatic acid, and partially dissolved ; and
the solution precipitated gelatine and the salts of iron. It
afforded, by incineration, a considerable portion of lime,
but no alkali. ‘eed :

"In comparing these facts it would scem that the preci-
pitate from infusion of galls consists partly of tannin and
gallic acid united to a small quantity of alkali, and partly
of these vegetable matters combined with calcareous earth ;
and it will appear probable, when the facts hereafter detailed
are examined, that both the potash and the lime are con-
tained in these compounds in a state of union with carboni¢

- acid.

The solutions of carbonate of soda and of carbonate of
ammonia, both precipitated the infusion of galls in a man- —
ner similar to the carbonate of potash; and each of the pre-
cipitafes, when acted on by boiling water, left a small quan-
tity of insoluble matter, which seemed to consist chiefly of
tannin and carbonate of lime.

The entire precipitate by carbonate of soda produced,
when incinerated, carbonate of soda and carbonate of lime.
The precipitate by carbonate of ammonia, when exposed to
a heat suflicient to boil water, in a retort haying a receiver

we oe Si ih ele attached

constituent Parts of astringent Vegetables. 73

attached to it, gave out carbonate of ammonia, {which was
condensed in small erystals in the neck of the retoit,). and
a yellowish fluid, which bad the strong smell and tasie of
this volatile salt. After the process of distillation, the solid
ynatter remaining was found of a dark brown colour; a part
of it readily dissolved in cold water, and the solution acted
on gelatine.

The residual fluid of the portions of the infusion which

had been acted on by the carbonates of soda and of ammo-
nia, as in the instance of the carbonate of potash, gave no
precipitate with gelatine, till they were saturated with an
acid; so that in all these cases the changes are stnetly
analogous.
_ The infusion of galls, as appears from the analysis, con-
tains in its primitive state calcareous matter.. By the action
of the mild alkalis, this substance is preciptated in union
with a portion of the vegetable matter, in the form of an
insoluble compound. The alkalis themselves at the same
time enter into actual combination with the remaining
tannin and galiic acid; and a part of the compound formed
is, precipitated, whilst another part remains in solution.

When the artificial carbonates of lime, magnesia, and
barytes, were separately boiled with the portions of infu-
sion of galls for some hours, they combined with the tan-
nin contained in it so as to form. with it insoluble com-
pounds; and in each case a deep green fluid was obtained,
which gave no precipitate to gelatine even when an acid
was added, but. which produced a deep black colour in the

solutions of the salts of iron.

Sulphate of lime, when finely divided, whether natural
or artificial, aiter having been long heated with a smal}
guantity ot the infusion, was found to have combined with

fe tanuin of it, and to have gained a faint tinge of light

brown. The liquid became of a blue-green colour, and
acted upon the -salts of ivon, but not upon gelatine; and
there ‘is every reason to suppose that it held im solution a
triple compound, of yallic acid, sulphuric acid, and lime.
Ve owe to Mr. Proust the discovery that different solu-
tions of the neutral salts precipitate the infusion of galls
and he supposes that the precipitation is owing to their

‘combining with a portion of the water which held the ve-

gctable matter in solution. In examinine the solid matters

' thrown down from the infusion by sulphate of alumine,

jutrate of potash, acetite of potash, muriate of soda, and
muriate of barytes, I found them soluble, to a certain ex-
tent,

T4 Experiments and Observations on the

tent, in water, and possessed of the power of acting upon
gelatine. From the products given by their incineration
and by their distillation, I am, however, inclined to believe
that they contain, besides tannin, a portton of gallic acid
and extractive matter, and a quantity of the salt employed
in the primitive solution.

It is well known that many of the metallic solutions oc
casion dense precipitates in the intus.on of galls; and it has
been generally supposed that these precipitates are composed
of tannin and exiractive matter, or of those two substances
and gallic acid united to the metallic oxide; bui from the
observation of different processes of this kind, in which the .
salts of iron and of tin were employed, I am inclined to
believe that they contain also a portion of the acid of the
saline compound. :

When the muriate of tin was made to act upon a portion
of the infusion, till no more precipitation could be produced
in it, the fluid that passed through the filter still acted upon
gelatine, and seemed to contain no excess of acid; for it
gave a precipitate to carbonate of potash without producing
effervescence. The solid compound, when decomposed by
sulphuretted hydrogen, after the manner recommended by
Mr. Proust, was found strongly to redden litmus paper, and
it copiously precipitated nitrate of silver; whereas the pri-
mitive infusion only rendered it slightly turbid; so that
there is every reason to believe that the precipitate contained
miuriatic acid.

By passing the black and turbid fluid, procured by the
action of solution of oxygenated sulphate of iron in excess
upon a portion of the infusion, through finely-divided pure
flint, contained in four folds of filtrating paper, I obtained
a light olive-green fiuid, in which there was no excess of
sulphuric acid, and which [I am inclined to suppose was a
solution of the compound of gallic acid and su!phate of iron,
with superabundance of metallic salt. I have already men-
tioned that gallic acid, when in very small proportion, does
not precipitate the oxygenated salts of iron ; and Mr. Proust,
in his ingenious paper upan the Difference of the Salts of
Iron, has supposed that, in the formation of ink, a portion
of the oxide of iron in union with gallic acid is dissolved
by the sulphuric acid of the sulphate. This comes near to
the opinion that they foym/a triple compound ; and, in rea=
soning upon the general phenomena, it seems fair to con-
clude that, in the case of the precipitation of tannin by the
salts of tin and of iron, compounds are formed of oa

: aly

constituent Parts of astringent Vegetables. 75

and the salts; and that, of these compounds, such as con~
tain tin are slightly soluble in water, whilst those that con-
tain iron are almost wholly insoluble.

_ In examining the action of animal substances upon the
infusion of galls, with the view of ascertaining: the compo-
sition of the compounds of gelatine and of skin with tan-
nin, I found that a saturated solution of gelatine, which
contained the soluble matter of 50 grains of dry isinglass,
produced from the infusion a precipitate that weighed nearly
91 grains; and in another instance, a solution containing
30 grains of isinglass gave about 56 grains; so that, taking
the mean of the two experiments, and allowing for the small
quantity of insoluble matter in isinglass, we may conclude
that 100 grains of the compound gelatine and tannin, formed
by precipitation from saturated solutions, contain’about 54
grains of gelatine, and 46 of tannin.

A piece of dry calf-skin, perfectly free from extraneous
matter, that weighed 180 grains, after being prepared for
tanning by long immersion in water, was tanned in a por-
tion of the infusion, being exposed to it for three weeks.
When dry, the leather weighed 295 grains; so that, con-
sidering this experiment as accurate, leather quickly tanned
by means of an infusion of galls consists of about 61 grains
of skin, and 39 of vegetable matter, in 100 grains.

After depriving a portion of the infusion of all its tanning
matter, by repeatedly exposing it to the action of pieces of
skin, I found that it gave a much slighter colour to oxy-
genated sulphate of iron than an equal portion of a similar
infusion which had been immediately precipitated by solu-
tion of isinglass ; but I am inclined to attribute this effect,
not to any absorption of gallic acid by the skin, but rather
to the decomposition of it by the long continued action of
the atmosphere ; for much insoluble matter had been pre-
cipitated during the process of tanning, and the residuum
contained a small portion of acetous acid.

In ascertaining the quantity of tannin in galls, I found
that 500 grains of good Aleppo galls gave, ‘by lixiviation
with pure water till their soluble parts were taken up, and
subsequent slow evaporation, 185 grains of solid matter.
And this matter, examined by analysts, appeared to consist

Of tannin . - - - - 130 grs.

Of mucilage, and matter rendered insoluble by
evaporation - - - - 12

Of gallic acid, with a little extractive matter - 31

Remainder, calcareous earth and saline matter 12
The fluid obtained by the last lixiyiation of galls, as:
M. Deyeux

76 Extract from the third Volume of

M. Deyeux observed, is pale green; and I am inclined ta »
believe that it is chiefly a weak solution of gallate of lime.
The ashes of galls, deprived of soluble matter, furnish a
very considerable quantity of calcareous earth. And the
property which M. Deyeux discovered in the liquor of the
Jast lixiviations, of becoming red by the action of acids, and
of regaining the green colour by means of alkalis, I have
observed, more or less, in all the soluble compounds con-
taining 2 eallic acid and the alkaline earths,

[To be continued. ]

IX. Eatract from the third Volume of the Anah ses of
M. Klaproth.

[Continued from our last volume, p. 344.]
Anaiysis of the natural Muriate of Ammonia of Vesuvius.

Pawn the eruption of Vesuvius in the year 1794, which
continued several weeks, the vapours of ‘the burning lava
became in part condensed into concrete salts, which were
found under different forms in the crevices and hollows of
the upper scoriz of the lava after it had cooled. The prin-
cipal products of this natural sublimation are sal ammo-
niac and muriate of soda.

The sal ammoniac is sometimes pure, sometimes rian
yellow, and for the most part crystallised in prisms of four
planes a little inclined, exceedingly brilliant and tranispa-
rent.

Muriate of soda forms almost always shapeless strata of
salt fibrous in their fracture: it is rarely pure, and for the
most part mixed with an oxide of copper which commu-
nicates to it a green colour more or less intense, and be-
sprinkled in many places with small brilliant leaves of sparry
iron.

The sublimated sal ammoniac ought, without doubt, to
be considered asa product of the decomposition of water
and atmospheric air in this grand chemical operation of
nature.

Ii is not necessary to make a similar supposition to ex
plain the formation of the muriate of soda. The sea water
which penetrates to the facus af the volcano and concurs to
its eruption contains it ready formed, while the decompo-
sition of a part of.this salt furnishes ‘the free muriatic acid
which forms muriate of ammonia.

M. Klaproth found 3 in his analysis that_ this eras

pertectly

t
4
J

the Analyses of M. Klaproth. 77

perfectly pure, and that it contains only one-half per cent.
of muriate of soda. _He found a little more in that of a
variety the crystallisation of which was less regular.

The yellow variety has crystals of the same form: they
have a beautiful topaz colour which arises from the com-
bination of one-eighth per cent. at most of iron.

M. Klaproth’ was the more surprised at not finding sul-
phate of ammonia, as the muriate of that base was formed
in an atmosphere impregnated with sulphureous vapours.

Analysis of the Sal Ammoniac of Bucharia,

Bucharian Tartary furnishes an ammoniacal salt which
differs in its external characters from that of the lava of
Vesuvius. We have not yet obtained sufficient ideas re-
specting its formation and natural history. . {

M. Model is the first person who made mention of it:
he assures us that several quintals of it are annually trans-
ported to Russia and Siberia, which gives reason to presume
that it-is very abundant in Bucharia. The opinion he
forms, in regard to the rocks, is the more probable, as the
fragments of rock, which seem to be composed of argilla-
ceous schist or compact argil, are very often covered with
sal ammoniac. It is to be remarked, that among the grains
of this salt there are found also small insulated fragments
of yellow sulphur. M. Karsten has described it under the
name of conchoid sal ammoniac.

It is grayish white, has a rough surface, is not very bril-
liant on the outside, and has a vitreous splendour on its
fracture, which is perfectly conchoid. Its fragments are
irregularly angular; it varies from semi-transparency to
Opacity ; it is pliant, tender, light, of a pungent taste of
urine, and contains

Muriate of ammonia = < 97°50
Sulphate of ammonia - - 2°50
100

Analysis of Sassolin.

Natural sedative salt, known under the name of sassolin,
is a white salt interspersed with some spots of an isabella
colour, grouped in stalactites, soft and saponaceous to the
touch, easily pulverised, and composed, in a great measure,
of free boracic acid.

M. Hoefer first made known at Florence the boracic acid,
which he found in the waters of the lake Cherchiaso and
in those of the lake of Castel-Nuoyo.
od) Pro-

78 Extract from the third Volume of

Professor Mascagni found it concrete on the borders of
the warm spring of Sasso near Sienna, and gave it the name
-of sassolin.

A hundred parts of sassolin, dissolved in boiling water
and spint of wine, gave in their analysis

Boracic acid . - - - - 86
Sulphate of magnesia, containing alittleiron 31
Sulphate of lime - - ~ - 3

100

Supplement to the Article on Sassolin.

M. Klaproth joins to this analysis of natural boracic acid
that of a gray sandy powder mixed with fragments of mica,
which are colJected in the lagunas, and which was sent to
him under the name of loto.

ist. A small quantity of that powder communicated a
slight redness to water coloured by tincture of turnsole.

2d.. Four ounces of alcohol put to digest over 100 grains
of this powder, and filtered, gave no indications of boracic
acid: on the contrary, they gave reason to suspect sulphate
of lime.

3d. Water boiled with this powder acquires a taste of
sulphurated hydrogen, and strongly blackens a silver spoon.
It gave, by evaporation, sulphate of lime in fine needles
which, joined to that dissolved by the alcohol, weighed 5
grains.

4th. The powder, dried in a gentle heat, weighed 84
grains. Being spread out on a small capsule, and gently
heated, sulphur was dissipated: it lost eight grains of its
weight.

5th. The residuum roasted, with double the quantity of
potash, saturated afterwards with muriatic acid, evaporated
to dryness, redissolved in water and filtered, gave silex
which, when dried, weighed 54.

6th. The solution well neutralized was precipitated by
the succinate of soda; the roasted precipitate contained
three grains of oxide of iron.

7th. The remaining liquor then gave a precipitate by
caustic potash, which, added in excess, redissolved it.
Being saturated by an acid, and precipitated by carbonate of
soda, it deposited alumine which, when calcined, weighed
16 grains.

The

the Analyses of M. Klaproth. 79

The sandy substance, or loto, contained then in 100 parts

Silex - - - - - 54
Alumine - - - - 16
Oxide of iron - - - 3
Sulphur - - - - 8
Sulphate of lume - - - 5

The quantity of sulphurated hydrogen being very incon-
siderable, the greater part of the loss arises, no doubt, from
the water.

Analysis of the Salt of Idria with capillary Filaments.

The capillary salt of Idria (Holotricum Scopopolii) which
is found in fissures of the argillaceous schecferthon schist,
mixed with the aluminous schist of the mines of Idria, is
of a silver-white colour, and forms needle-like or capillary
crystals, which sometimes are more than two inches in
Tength. Hitherto they have been considered to be teathered
alum, composed of sulphurie acid, alumine, lime, and iron,
according to Scopoli. But the analysis of Klaproth has
shown the falsity of this opinion.

The result of this analysis proves that the salt of Idria
with capillary filaments contams neither alumine nor lime,
but that it is a natural compound of sulphate of magnesia,
containing a small quantity of the sulphate of iron.

Analysis of the Feathered Alum of Frayenwald.

The feathered alum, which is formed in part in the quar-
nies of argillaceous schist of Frayenwald, and particularly
by their Roce aon in the open air, has a white colour
inclining to gray. It is composed of capillary filaments
often crooked, united sometimes in bundles not very close,
and sometimes cemented, and forming a crust: it has a
moderate silky splendour.

A hundred parts of this feather alum contain

Alumine ~ . - - - - 15°25

Oxidulous iron - - - - ~ 7°50

Potash, sulphuric acid, and water of crystallisation 75-00

100

Analysis of Melilite.

It is to the celebrated mineralogist of Freiberg that we
have been indebted upwards of ten years for the knowledge
of this fossil, The constituent principles of it haye been

too

89 Extract from the third Volume of

too little known to enable us to assign to it, with precision,
a place 1 in the classification of minerals. On account of its
colour, which resembles that of honey, M. Klaproth calls
it melilite.

Mehlite is found at Arten in Thuringia, but ingulated and
in small quantity in strata of. turf:

The external characters by which it is known are as fol-
lows: It is generally of a honey colour, more or less dark,
and sometimes of a straw yellow. It has always been found
crystallised in octaédra: it is however rare that the crystals
are entire, and for the most part they have the form of py=
ramids with four faces more or less distinct. .They are

seldom found of a moderate size, being always for the most
part small.

The surface of them is generally smooth and brilliant,
sometimes rough and as if gnawed, but they have always
internally a vitreous splendour; their fracture is conchoid,
and the fragments are irregularly angular.

The ery stals are rarely perfectly diaphanous : : in general,
they are semi-transparent, and in the variety, which is of a
yellow colour, scarcely pellucid. Melilite is tender, fragile,
and easily pulverized. Reduced to powder, it is of a grayish-
yellow colour. Its specific gravity is 1550.

There are found also sometimes in the same coal mines
small pale yellow crystals of native crystal, which have a
resemblance to the straw coloured var tety bf melilite.

It was at first believed that melilite is a combusttble fos-
sil, similar to amber. Its exterior characters seemed also to
confirm it. But if the character of a non-metallic com-
bustible fossil is to feed the flame which consumes it, .this
is not the case with melilite: when burnt it. simply be-
comes white without being able to maintain combustion
of itself. ;

M. Gilet Lamont has besides proved, in the Journal de
Chimie for 1791, that melilite 1s not crystallized amber as
baron de Born supposed,

Other mineralogists have supposed that this fossil is sul-

hate of lime impregnated with oil of petroleum, from
which its yellow colour arises. This opinion arose probably
from the white colour which this fossil acquires by com-=
bustion. It is however possible, considering its rarity, that
it has been imitated by selenite coloured and cut artificially
into crystals of the same fori.

It was only from chemical analysis that a more.correct
knowledge of this fossil could be obtained. Messrs. Lam~

padius and Abich undertook this labour and published an,
account

> a

the Analyses of M. Klaproth. 81

account of it almost at the same time. But their results ex-
hibit very considerable differences :

For melilite, according to Mr. Lampadius, is composed
of

Carbon - - - - 85'5

Oil of petroleum - - 13°5

Silex - - - - 20

Water of crystallization - 5:0

96°0

According to Mr. Abich, it contains

Benzoic acid - mye [hh 5
Carbon ~ - - - 40

Water of crystallization = 28
Carbonate of alumine - - 16.
Benzoate of alumine - - 5

Oxide of iron - ~ - 3

Resin - - - - - 2

100

The striking difference between these two analyses in-’
duced M. Klaproth to repeat them. He made his experi-
ments on a pretty large quantity of melilite. The details
are as follows:

Preliminary Trials.

1st. Melilite placed on burning coals, or well exposed to
the flame of a taper, loses its transparency and yellow co-
lour. It becomes white, punctured with black, and at
length altogether white, like chalk. In this operation nei-
ther smoke nor sensible light is perceived.

2d. If melilite, reduced to a powder, be boiled with a
sufficient quantity of water, this fossil becomes decomposed ;
the water acquires the properties of an acid, and suffers to

be deposited a gray flaky earth.

3d. The entire crystals of melilite immersed in nitric acid
dissolve completely, without heat, in the course of a.few
minutes. The liquor always remains clear till they are
entirely dissolved. This process exhibits a sure and easy
means of distinguishing real melilite from adulterated sub-
stances with which it might be confounded. .
. 4th. If the crystals be put into muriatic acid, ‘the acid
does not remain clear like the nitric acid ; it becomes whitish
Vou. XVII. No. 65. F and

BE" Extract from the third Volume of

and nebulous : the crystals even are not entirely dissolved at
the end of some days.

_ 5th. In concentrated sulphuric acid, fragments of mililite
do not fall to the bottom but float at the surface. They are»
gradually converted into white flakes, without giving clear
solutions : this, however, takes place when the acid is di-
hated with water.

6th. Acetic acid exercises no action on melilite,

7th. Solution of caustic soda converted fragments of this
fossil into white flakes, and dissolved them almost entirely.

8th. Solution of caustic ammonia changed them also at
Jengtlr into white flakes, but without dissolving them. \

Meliiite thrown on,saltpetre in a state of fusion, pro-
duced no real detonation, The morsels of this fossil burn
merely with a faint and transient light, and become mixed
with the fused saltpetre under the form of a white earth.

M. Klaproth then analyzed them in the dry and in the
moist way.

Pst. Fifty grains of pulverized melilite, mixed with 75
grains of crystallized carbonate of soda, were boiled in a phial
with a sufficient quantity of water. There was a reciprocal
action between. these two substances, with a disengagement
ef the carbonic acid of the seda. After the decomposition
of the melilite effected by the soda, the earthy part depesited.
on the filter, when washed and dried, weighed 83 grams, —
and was found to be alumine.

The soda in solution was in a great measure neutralized :
Mr. Klaproth completed the saturation of it with acetous
acid, and evaporated the liquor gently to dryness. The
acetite of soda thence resulting was separated from the
saline mass by small quantities of alcohol poured over it
at several times. The residuuin was then dissolved in water,
from which were precipitated crystals of a neutral salt, the
acid of which had consequently been furnished by the me-
hihite.

It results from this analysis that melhiite is composed of
alumine and an acid.

ad. Fitty grains of pulverized melilite put into a stopped
flask, containing a coid selution of caustic ammonia, and
frequently stirred, were decomposed ; and twenty-four hours
after the bottom of the giass was lined with a multitude
of small crystals of a neutral salt, formed by the acid of
the melilite and.ammonia: they were covered with a slight
brown stratum of alumine, arising from the decomposition
of that fossil. The liquor was heated, and diluted with a
% : sufficient

aw

the nalyses of M. Klaproth. — 83

sufficient quantity of water to dissolve the crystals, after
which it was filtered: it then deposited, by evaporation,
small prismatic crystals with six planes.

3d. Fifty grains of melilite coarsely pulverized, and on
which weak sulphuric acid was poured, were soon com-
pletely dissolved, without heat, except some carbonaceous
parts and a few grains of quartz accidentally adherent. The
solution filtered, and then concentrated, coagulated into a
soft mass, ramified by small crystals in needles, without
giving any appearance of real crystals of alum, which proves
that melilite contains no potash.

In the decomposition of 100 parts of melilite in the dry
way, a great deal of carbonic acid and hydrogen gas, &c.
was disengaged.—These Mr. Klaproth collected under bells
filled with mercury, and prove that the acid of melilite
is analogous to vegetable acids ; that it is composed of car-
bon, hydrogen, and oxygen, and consequently decompo-
sable by fire. The residuum in the retort was black and
brilliant. The fragments had lost nothing of their form or
volume. They weighed 5 grains. When calcined in the
open air, they gradually lost their black colour and their
carbon: they became yellowish-blue : they weighed 16
grains. When dissolved in sulphuric acid they gave, by
the addition of acetite of potash, crystals of alum.

A hundred parts of melilite, analyzed in the dry way,
gave
34 inches in a line of carbonic acid gas
25 ——_—_-—_——. of hydrogen gas
38 grains of acidulous and aromatic water

2 of aromatic oil
9 of pure carbon
16 of alumine, combined with a little silex.
Decomposition of Melilite by Water.

Four hundred grains of melilite boiled for two hours
with 60 ounces of water were decomposed: the decompo-
bition when filtered to separate the alumine gave, by eva-
poration, crystals in needles, and an acid mass of small balls
formed of diverging radii proceeding from one center. It
remained to be known whether this acid of two radicals
could belong to any of the known vegetable acids, or whe-
ther it had characteristic properties which ought to make
it be considered as a particular acid.

_ The properties by which it is distinguished from all the
other vegetable acids ‘are as follows :

Ist. Melitic acid crystallizes into fine needles, or globules,

Fo formed

84 Extract from the third Volume of

formed by the union of its needles, or in small hard prisms.
This acid, however, does not seem at first to possess the
property of crystallizing. It is probable that it gradually
acquires it by the absorption of the oxygen of the atmo-
sphere.

ed. This acid, when put upon the tongue, has at first a
sweetish-sour taste, and then leaves a bitter savour.

_. $d. If put upon a warm plate of metal it is readily de-
composed: itis dissipated in abundant gray fumes which,
however, do not affect the smell. There remains a small
quantity of ashes, which produce no change in red or blue
tincture of turnsole.

4th. When neutralized by potash it crystallizes into long
prisms grouped together.
5th. When saturated by soda it crystallizes into cubes
or triangular plates, sométimes single, and sometimes in
groupes.
6th. When saturated by ammonia it crystallizes in beau-
tiful prisms with six planes, which soon lose their transpa-
rency in the air: they have then a silvery-white eolour.
7th. Melitic acid dissolved in lime water, into which a
solution of barytes or of calcined strontian is poured, drop
by drop, produces a white precipitate; but which, if mu-
ratic acid be poured into it, becomes redissolved.
sth. When poured into a solution of acetite of barytes
it produces, in like manner, a white precipitate capable of
being redissolved by the addition of nitric acid.
gth. It produces no cloud, or precipitate, in solution of
muriate of barytes; but some time after very fine crystals
in transparent needles are deposited.
10th. Solution of nitrate of silver remains clear, and ex-
periences no change by the addition of melitic acid.
11th. Melitic acid poured into a solution of nitrate of
mercury, prepared either hot or cold, produces in it a very
abundant white precipitate, which is immediately redissolved
by the addition of a new quantity of nitric acid.
_ }9th. When poured into a solution of nitrate of iron it
gives a very abundant precipitate of an isabella colour, ca-
pable of being redissolved by the addition of muriatic acid.
. 13th. Poured into a solution of acetite of lead it gives,
in like manner, a very abundant precipitate, which is im-
mediately redissolved by the addition of nitric acid.
14th. Poured into a solution of acetite of copper, it gives.
a grayish-greew precipitate.
15th. But a solution of muriate of copper experiences
na change.

6th. It

the Analyses of M. Klaproth. 85

16th. It has never yet been possible to convert it into
oxalic acid by means of nitric acid. The only change which
M. Klaproth remarked was, that its brownish colour be-
came a straw-yellow.

The precipitate of lime water-by this acid immediately
redissolves by the addition of nitric acid.

These first trials, in regard to the affinities of melitic
acid, are sufficient, however, to prove that it is susceptible
of combining with several earths and metallic oxides ; and
that its affinity is stronger than that of the acetic acid and
Jess than that of the mineral acids. This acid, composed
of carbon, hydrogen, and oxygen, which is susceptible of
decomposition by heat like the vegetable acids, participates
then in their nature; but differs irom them by its proper-
ties as well as by the proportion of its principles. ‘This
induced M. Klaproth to consider it as a particular vegetable
acid, to which he has given the name of melitic acid.
Acidum melilithicum.

What place will be now assigned in the methodical clas-
sification of fossils to that which affords the first instance of
alumine, combined with a vegetable acid? Melilite belongs
to the mineral kingdom by its base, and to the vegetable by
the constituent principles of its acid, and by the origin of
its formation amidst beds of coal: but coals being con-
sidered as fossils, though they arise from vegetable remains,
mineralogists will have a right to class melilite among the
fossils with a base of alumjne.

The following is the proportion of the principles of which
it is composed : oat

Melitic acid - - - 46
Alumine ~ - : 16
Water of crystallization - 38

100

Analysis of the muriated Lead Ore of Derlyshire.

The regular crystals of this muriate of lead, already de~
eribed by Mr. Karsten in his mineralogical tables, are formed
of cubes of from four to six lines, with blunted edges ; the.
decrements on the edges produce a great many varieties in
their exterior form. Murjate of lead exposed on charcoal,
at the extremity of the flame of the blow-pipe, immedi-
ately fuses into an opake globule of a beautiful orange-
colour, which becomes lemon-yellow, and then white, by
covling; and the surface of th: button seems to be shehtly

F 3 striated,

86 - Exiract from the third Volume of

striated. When the charcoal inflames at the place where the
globule adheres to it, the latter breaks in pieces, the mu-
rlatic acid escapes in white vapours, and the charcoal is
covered with grains of metallic lead. YS
M. Klaproth has found in the crystals of muriate of lead
treated by potash in a platine crucible, and by nitric acid,
Oxide of lead - - ~ 85°50
Muriatic acid - - - 8°50
Carbonic acid, witha little water 6

100

Astificial muriate of lead contains 13 or 14 per cent. of
concrete muriatic acid, while natural muriate of lead is not
completely saturated ; which explains why the carbonic acid
may be found there at the same time as muriatic acid.

Analyses of the Green Phosphate of Lead of Zschopan.

This ore is composed of hexaédral prismatic crystals, ter-
minated by planes perpendicular to the axis. They are
sometimes single, and sometimes formed into groupes; some
of them are two inches in length. They are of an olive or
green, sometimes inclining to meadow-green, and often
to pale yellow ; when pounded, they give a straw-coloured
powder. The crystals, when very pure, have a smooth
surface and a greasy polish; they are generally covered with”
a stratum of ochre which renders them rugged. The matrix
from which they are extracted is white sulphate of barytes.
The specific gravity of this substance is 6°270.

This phosphate of lead, when exposed on charcoal to the
flame of the blow-pipe, fuses into an almost transparent
globule; but it becomes opake by cooling, and soon cry-
stallizes under the form of a polygonal garnet, with brillant
facets on the side which touches the charcoal. There are
generally found small grains of lead reduced to the metallic
state, but it is never entirely reduced without a flux. It
participates in this property of crystallizing, by cooling, with
all the ores of phosphate of lead hitherto known, as well
as with artificial phosphate of lead. This observation had
before been made by Cronstedt.

To fuse this ore a very strong heat is required; for M.
Klaproth extracted it without its having experienced any al-
teration except at its edges, which were a little blunted by
the muffle of a cupelling furnace, in which he had effected
exceedingly well the separation of gold; but it fused
completely in a blast-furnace, and crystallized in radu by

cooling,

ihe Analyses of M. Klaproth. aT

eodling, nearly in the same manner as sulphur of which its.
crystals assume also the colour.

The phosphate of lead of Zschopan reduced by black
flux, and treated by the nitric and sulphuric acids to obtain
phosphoric acid, is composed of

Oxide of lead - - = 73°40
Phosphoric acid - - 18°37
Muriatic acid = - - 1:70
Oxide of iron - - - 0:10

98°57

_ That of Hoffsguind, near Fribourg, in the Brisgaw, con-
tains

Oxide of lead - - - 77°10
Phosphoric acid - - 19
Muriatic acid - - - 1°54
Oxide of iron - - - O10
O7T°T4

The brown ore of phosphate of lead of Huelgoet in Brit-
tany contains

Oxide of lead - > - 78°58
Phosphoric acid - - 19°73
Muriatic acid - - - 1°65

99°96

The crystals subjected to this analysis were composed of
hexaédral prisms agglutinated together, of the size of a
goose’s quill, and half-an-inch in length. Their specific
gravity, according to M. Klaproth, is 6-600.

The lemon-coloured ore of phosphate of lead of Wan-
Jochhead in Scotland fuses, on coals, inte a whitish green
epake globule with some large brilliant facets, or facets the
surface of which is covered with radii that cress each ether.
it contains

Oxide of lead ~ - - 80

Phosphoric acid stad 18
Muriatic acid - - - ° 1.62
99°62

The yellow colour of this ore seems tg arise merely from
F4 a greater

88 Analysis of Ambergris.

-4@ greater oxidation of the lead. If pulverized, and if a
solution of muriate of tin be poured over it, in a close yes~
sel, it loses its yellow colour and becomes white.

[To be continued. ]

X. Analysis of Ambergris. By Bourtton-LaGRANcE*.

I, is is now almost generally admitted that ambergris is
found in the stomach of the cachelot, called by naturalists
Physeter macrocephalus, and that it seems to be the product
of its digestion.

Dr. Swediaur has proved in his Researches on the Nature
and Origin of Ambergris, that the beaks of the sepia, with
which large pieces of ambergris, both those found on the
coasts or at the surface of the sea, and those taken from the
bellies of these whales, are mixed, belong to that species to
which Linnzus has given the name of Sepia octopoda. The
existence of these beaks and of other foreign bodies in am-
bergris is a convincing proof that it has been once in a state
of softness or liquidity. M. Swediaur says, that the kind of
whale which contains ambergris in its belly is that species
from which spermaceti is extracted, which seems to be the
Physeter macrocephatus of Linnezus, and which feeds chiefly
on the large species of sepia. It is in the intestinal canal
of this whale that the ambergris is found: to the animal it
is a source of disease: this matter when it issues from the
bag which contains it gradually acquires that solidity which
it 1s observed to possess.

Ambergris is found in the Indian seas, near the Moluc-
cas, the Maldives, and Madagascar, and on the coasts of
China and Japan, and from Iolo to the Manillas. It is
often picked up on the coasts of Maragnon, or of Brasi!,
but more commonly on those of Africa towards Cape Blanc,
the Gulf of Arguin, the Bay of Portendia, and in some
other islands which extend from that of Mosambique to
the Red Sea.

According to the accounts of several travellers the inha-
bitants of the isles of Sanballat search for it in a very sin-
gular manner. After storms they proceed along the shore,
and if there be ambergris on it they perceive it by the smell.
There are certain birds and other animals on these shores

-which are fond of ambergris; and as they discover it at a

* From the Aunales de Chimic, No.1 3y ;
eo distance

Analysis of Ambergris. 89

distance by the smell, they go in search of it in order to
eat it. pee

There can be no doubt that ambergris is an animal pro-
duction. Several substances approach very near to it in
smell, such as the excrements of some of the mammalia,
and particularly those of oxen and pigs. I found that cows’
dung dried in the sun has an odour very analogous to am=
bergris, and even to musk ; and hence the name of zndige-
nous musk given in some countries to this substance pre-
pared in this manner. '

Ambergris (ambrea grisea) is a light substance which
floats on the water, solid, opake, of an ash colour, veined
with white and yellowish-brown, slightly odoriferous, but
the odour of which develops itself as it grows old, or when
it is. mixed with musk or other aromatous substances, as it
is prepared for perfumes or smelling waters.

Good ambergris in its natural state may be known if
when scraped with the blade of a knife it adheres to the
knife like wax, if it retains the impression of the nails and
that of the teeth, and if, when pricked with a hot needle,
it emits a fat odoriferous juice. Though solid, and in ge-
neral brittle, it is not sufhciently hard to bear polishing, but
rubbed with the nail it becomes smooth like hard soap.

Geoffroy, Neumann, Grim, and Brow, have classed am-
bergris among the bitumens. The analysis made of it by
chemists is nut sufficient to determine the nature of this
substance. Ambergris fuses in the fire, says Geoffroy, intoa
resin of a yellow or gold colour; when applied to a flame it
kindles and burns; spirit of wine does not dissolve it en-
tirely, there remains a black matter like pitch on which it
has no action. When dissolved it leaves some time after
a white nebulous sediment, which gradually coagulates and
becomes thicker and thicker; this coagulum being dried
changes into a brilliant foliated earth, and which is not
different from spermaceti.

In distillation, according to the same chemist, ambergris
gives first an insipid phlegm, then an acid liquor or spirit, -
and a highly odorous yellow oil, with some portion of acid.
and volatile dirty salt: in the last place there remains at
the bottom of the retort a brilliant, black, and bituminous
matter. It is here seen that this analysis, which does not
differ from that given by all chemists, deserves to be re-
examined in order to give us correct ideas respecting the
nature of this singular substance. ;

I think it my duty to acquaint those who may be desirous
of repeating these experimentsy to be very careful in Pees

choice

90 Analysis of Ambergris.

ehoice of the ambergris, Several varieties are common itt
eommerce, the price of which establishes different species.
There is no doubt that this substance is fabricated, as cas-
torium, is made.in some countries of Germany. Bayen as=
sured me that he saw it made at Irankiort. ‘This tather of
ehemistry found that his memory did not deceive him; and,
what is rare among travellers, he told the truth.

I have examined several kinds of ambergris used in com-
merce. Some of them vary in specific gravity, have a co-
Jour more or less dark, with very little odour, and are flexi-
ble; others are of an ash-gray colour, pretty hard: in the
last place, others are almost stony, are scarcely soluble in
alcohol, and have no odour.

The ambergris which I analysed was not purchased. I
compared it with that in the cabinet of the Museusn of Na-
tural History, and found no difference either in the colour
er odour,

Physical Properties.

It is of an ash-gray colour, interspersed in the inside
with some yellow striz ; has a sweet mild odour, and grows
soft between the fingers. When reduced to a fine powder
it acquires a darker colour; pounded in a glass mortar it
becomes agglutinated and adheres to the pestle.
__ Its taste 1s dull and almost insipid, and when put between

the teeth it exhibits the same phenomena as wax.

Its specific gravity is from 844 to $49: that of water
being 1000.

According to Brisson the specifie gravity of ambergris is
9263. The weight of the cubic inch 4 gros 58 grains ;
that of the cubic foot 64 pounds 13 ounces 3 gros 47 grains,

The specific gravity of blackish ambergris 1s 7803. The
weight of the cubic inch 4 gros 3 grains; that of the cubic
foot 54 pounds 9 ounces 7 gros 35 grains.

Chemical Properties.

Exp. 1. Ambergris, when placed on burning charcoal,
burns, and becomes entirely volatilized: it then leaves an
agreeable odour.

If this combustion is effected more slowly in a platina
crucible it fuses, emitting the same odour; that of a fat
body is also distinguished.

Nothing remains in the crucible but a black greasy spot.

Fifty degrees of heat (Reaumur’s thermometer) are suffi-
cient to fuse it. A brown brilliant liquid is thus obtained.

At 80 degrees it is volatilized under the form of white
yapours. :

ea , Exp.

Analysis of Ambergris. ’ $1

Exp. H. The odour developed during its volatilization,
having made me suspect the presence of an acid analogous
to that of balsams, an experiment was made to ascertain
it.

_ A bit of ambergris was placed in a porcelain capsule co-
vered by-a bell, in which was suspended a paper tinged with
turnsole. The apparatus being placed on a sand-bath, the
temperature was raised to the écgres necessary io volatilize
the ambergris: the paper speedily assumed a red colour.
Nothing was now necessary but to discover the nature of
this acid ; and with this view Scheele’s process for extract-
ing acid of benjamin was employed.

The product was examined, and left no doubt in regard
to its analogy.

Exp. Ill. The analysis with the retort added nothing to
the knowledge already acquired in regard to the nature of
ambergris.

A gentle temperature makesit fuse: in a more elevated one
it is “ae and a whitish acid liquor and a light oil
soluble in part in alcohol, which gives it a yellow colour,
pass over into the receiver. There remains in the retort a
light and very voluminous charcoal.

_ Exp. IV. Ambergris floats on water, and does not suffer
itself to be penetrated by that liquid cold: it acquires nel- |
ther odour nor savour. Boiling water produces no alteration
on it. At that degree the ambergris dissolves and appears
under the form of a brownish oily liquid : a small quantity
of a black matter insoluble in alcohol is separated. The
filtered liquor had neither odour nor colour, and only a slight
bitter savour.

It is only in the ratio of the temperature, then, that am-
bergris dissolves, since in proportion as it is lowered it is
found to have the same properties.

Exp.V. Acids in general have very little action on am-
bergris. It has not yet been possible by the aid of these
agents to discover the constituent parts of this compound.

Weakened sulphuric acid makes it experience no change.
If concentrated, it lays bare little of the oxide of carbon.

The same phenomena are exhibited by the muriatic and
oxygenated muriatic acids.

Nitric acid raised to 18 degrees, and distilled from off
that substance, in a pneumatic apparatus, gives for result
nitrous gas, carbonic acid, and azotic gas.

The latter arises, no doubt, from the decomposition of
some animal matters accidentally mixed with the ambergris,

as

92 Royal Academy of Madrid.

° may be observed in the examination of some fragments
of it.

There is found in the retort, after the elastic fluids are
extracted, a thick liquid inclining to yellow: when brought
to a soft consistence the matter swells up a little, and when
evaporated to dryness in a porcelain capsule there remained
a dry brittle matter of a golden-yellow colour, brilhant and
transparent, which exhibited characters analogous to resins.

[To be continued, ]

——— Ss = oe

XI. Proceedings of Learned and Giconomicat Societies.
ROYAL ACADEMY OF MADRID.

fe learned body, in its sitting of August 19th, admitted
among the number of its corresponding members John
Baptiste Leonard Durand, author of a voyage to Senegal,
and sent him a diploma. It transmitted to him also at ‘the
same time the following observations on the solar eclipse,
made at Tangiers by Ali Beik Abdallah, a young Moor,
educated in Europe, who has already distinguished hunself
by his talents, his love for science, and the” service he en-
deavours to render to it.

Olservations.

The sun appeared eclipsed above a hall which intersected
the horizon at 17° 24".13°. A large spot which was situ-
ated near the sun’s centre emerged from the shadow at 18*
28" 25°. End of the eclipse, exterior contact 19 14™ 155,

The observer employed a small telescope, by Dollond,
which he calls a military one, of a foot focus, the eye- lass
of which he smoked; the time was given by his chrono-
meter, which he _ compared with the heavens, by the mean
of 40 altitudes of the sun taken on the 16th and 17th with
his pocket sextant and a glass horizon.

The part eclipsed seemed to be about eight digits, Wich
shows the great influence of parallax.

He propuses to determine the longitude and latitude, of |
which, as yet, he has had only an approximation,

M. Delalaade, who observed this eclipse at Paris, has
deduced from it, that the difference of meridians between
Pangiers and Paris is 33" 12° in time, which is only 32 se
conds more than it was supposed to be before, but which
stood in necd oi this confirmation. ;

SOCIETY

Society of National Giconomy, Haarlem. 93

SOCIETY OF NATIONAL GECONOMY, HAARLEM.

This society has published the following
Prize Questions :

1. What species of nettiec can be employed in making
yarn? The memoir must state what country produces it;
the proper season for gathering, and the manipulations ne-
cessary in preparing it for use. Twenty-five pounds of the
yarn must be produced with’ the paper. The prize is 25
ducats, which will be augmented 1f 50 pounds be sent in.

2. Can the acorn be employed for making oil, as a sub-
stitute for coffee, or other purposes of domestic aeconomy ?
and what are the best methods for doing so? The prize is
six ducats.

3. What is the present state of public and private ceco-
nomy in Holland ?

4. What is the best method of preventing or curing the
rot in sheep? Fifty ducats to. the person who shall point
out the cause of the disease, and an effectual method of pre-
vention ; twenty-five ducats to the one who shall point out
a cure.

The answers to the above questions must be sent to the
secretary of the society before the 30th of September 1804.

5. Millet being little cultivated in Holland, and no good
method known for separating it from the chaff, the society
offers a premium of twenty-five ducats to the person who
shall invent a machine by which that can be effected as
completely as in the millet imported from other countries.
The competition for this prize will be open till the 3eth of
September 1805.

CCONOMICAL SOCIETY, ST. PETERSBURGH.

This society has offered several premiums for encouraging
industry among the peasants and the poor in hospitals ; also
for a good method, suited to the capacity of the Russian
peasant, for the preservation of health, enabling him to
apply remedies, especially from indigenous plants, with
the manner of employing them. The prize for the latter
is a gold medal of fifty ducats.

XII. Jn-

{f 9 ]

XII. Intelligence and Miscellaneous Articles.
VACCINATION A PREVENTATIVE OF THE PLAGUE.

Extract of a Letier from J. pe Carro, M.D. of Vienna,
éo Dr. C. F. Haue, of Rastadt.

August, 23, 1803.

Wuat will excite your admiration, as well as that of thé
whole world, is a new discovery made by two physicians,
namely, Dr. Aubon, of Constantinople, and Dr. Lafond,
of Salonica, in Macedonia. The experiments of these two
physicians, who never have had any intercourse, confirm
that the vaccine is a preservative against the plague. The
proofs of the former are, that of 6,000 persons inoculated
with the vaccine at Constantinople, not one of them was at-
tacked by the plague; that children subjected to the vac-
cihe imoculation were made to suck mothers attacked by
the plague without any of them being infected; that an
Italian physician, who devoted himself in Turkey to the
study of the plague, being fully convinced of the property
which the vaccine has of preserving from this malady, took
every opportunity of coming into contact with persons in-
fected by the plague, im an hospital destined for patients
afflicted with that disease: that in consequence of accurate
researches the vaccine pustules have been found on the teats
of the cows, and the hands of those who milk them, in
the villages around Constantinople: that it results from the
account of persons worthy of credit, that in their country
neither the plague nor the small-pox have ever prevailed
epidemically, even when these scourges made the greatest
ravages im the neighbourhood: that when an imhabitant of
these villages has been infected with the plague in distant
countries, and returns with that malady, he has either died
or been cured without the disorder spreading: in the last
place, that the confidence of several classes of men, and
chiefly of the Armenians, in the preventive quality of the
vaccine against the plague, is so great, that a number of
people are inoculated every year with it to preserve them
from this malady The physicians of Constantinople ‘have
begged me to contribute towards the promulgation of this
new discovery, &c.

PRUSSIC ACID. ;
Dr. Schaub, of Cassel, in a letter to Mr. Parkinson, has
given a new process for obtaining this acid in a state of ab-
or : solute

Phosphate of Soda.—Sulphate of Soda, &e. 95

solute purity. It consists in pouring upoh one patt of
Prussian blue half a part of sulphuric acid, diluted with aft
equal quantity of wate*, and subsequent distillation. The
prussic acid passes over in the alcohol*. Its odour sreatly
resembles the water of the Lauro-cerasus. It is 4 deadly
poison io animals,

PHOSPHATE OF SODA.

M. Funcke, a German apothecary, gives the following
as amore ceconomical, expeditious, and easy process for
preparing this substance than any in common use:

Saturate the excess of lime contained in calcined bones.
with dilute sulphuric acid, and dissolve the remaining phos-
phate of lime in nitric acid. To this solution add a like
quantity of sulphate of soda, and then recover the nitrieé
acid by distillation. The phosphate of soda is then to bé
separated from the sulphate of lime by affusion with water
and crystallization in the usual manner.

SULPHATE OF SODA.

The same chemist has published a new method of pre-
paring sulphate of soda from sulphate of lime. It consists
in making into a paste, with a sufficient quantity of water,
eight parts of burnt gypsum (sulphate of lime), five of clay,
and five of common salt. This mixture is burnt in a kiln
or oven, and then ground to powder, diffused in a sufficient
quantity of water, which, after being strained and eva-
porated, is suffered to crystallize.

POTASH.

The ashes of vegetables in general contain only from
18 to 20 per cent.; these of buck-wheat, according to
some experunents of Vauquclin, about 33 of this alkali.

’ s ‘

GALVANISM.
Professor Tromsdorff has announced that metals may be

deflagrated by means of the Galvanic fluid, in hydrogen,
ammonia, nitrogen, nitrous and carbonic acid gases.

TITANIUM.

: Professor Lampadius has succeeded in reducing to the
metallic state, by means of charcoal only, the oxide of

* We have copied this from Mr. Nicholson's valuable Journal, but
there is some inaccuracy in it. If water only was employed there could
be no alcohol produced; ‘if the latter was empioyed in place of water
then cither might pass into the receiver,

titanium

96 Tungsten.—Stencilling.

titanium, obtained by decomposing the gallate of that metal
by potash or soda. The metallic titanium is of a dark
copper colour, has much brilliancy, is brittle, but possesses,
in small scales, a considerable degree of elasticity: it tar-
nishes on exposure to the air, “and is easily oxided by heat,
which gives it a blueish aspect: it detonates with nitrate of
potash and is highly infusible. All the dense acids act upon
it with considerable energy.

TUNGSTEN.

Richter, the German chemist, has published the follow-»

ing method of obtaining tungsten:

Expose equal parts of tungstic acid* and dried blood for
some time to a red-heat in acrucible; put the black powder
which is formed into a smaller crucible, and expose it again
to a violent heat in a large fire for at least an hour. The
result is tungsten in its metallic state.

STENCILLING.

On this process,’ which is employed in different manu-
factures, we have received a communication from Mr. T.
Gill, which we think furnishes a very useful hint, and may
possibly lead to an extension of the use of stencils :

“* Wishing,” says he, “* to produce some copies of a
miniature profile, lately taken by Mr. Hawkins’s patent
method (viz, by a machine, which being traced over the face
itself, at the same time draws the outlines of the profile on
a reduced scale), which was cut in thin wove post paper; I
coated it pretty thick on both sides with the cement No. xvil.
described in the Philosophical Magazine, vol. xiv. p. 122;
which dried instantly, and rendered it perfectly impervious
to- oil and water, aud sufficiently stiff. . In short, the paper
became a very excellent stencil, with which I was enabled
_ to multiply the profiles with as muclr facility as if it had
been a brass impression plate. I think the above informa-
tion may be useful to manufacturers of paper hangine’>
cards, floor cloths, and in short to all who employ stencils;
asa method of preparing them, far superior to that in gene-
ral use ; which consists in coating them with boiled linseed
oil, as the.oil, requires much time to become dry, and, [be-
lieve, would never render the stencil so firm and durable, as
by this new process.”

* Or more properly tungstic oxide; tungsten, by some late experiments,
appearing not to be acidifiable. '

SESS

es

E 97]

NIL. Essay on the Franklinian Theory of Electricity. By
SamMuEL Woops, Esq. Read before the Askesian So-
ciety in the Session 1802-3.*

< eae science of electricity offers an extensive and interest-
iug field of inquiry to the curious and speculative mind:
the diligence of observation and experiment has collected
an almost unlimited variety of facts, which it is often diffi-
cult to refer by any perspicuous classification to a few sim-
ple and general principles ; and notwithstanding the endea-
vours of philosophers well qualified by their situation,
talents and pursuits, to examine the effects, ascertain the
properties, and investigate the laws of this singular fluid, it
is still an arduous task to discover the connecting links
which unite the numerous phenomena in one luminous and
consistent system. Those striking appearances which ar-
rest attention and create astonishment, are perhaps less cal-
culated to convey substantial information than an accurate
and repeated scrutiny into the minuter effects and operations.
‘The recent and surprising discoveries in Galvanic electricity
may convince us that our knowledge hardly penetrates be-
neath the surface. We know, indeed, that by rubbing a
piece of glass or sealing-wax particular signs and actions
are produced, which may be communicated to, and in cer-
tain circumstances retained by, other bodies ;: and we im-
pute these signs and actions to the influence of a peculiar
fluid, which we denominate electricity. But we are yet
unable to conceive the reason or the means by which fric-
tion generates this power, or how its passage is obstructed
or impeded by some particular substances : vapours, clouds,
fogs, rain, and even the atmosphere, almost universally
and uniformly indicate, when examined by delicate instru-
ments, the presence of electricity ; and though it is reason-
able to conclude its agency of great extent’and importance
4m our system, we are still ignorant what office is assigned
to this subtile fluid in the ceconomy of nature. ,
It has justly been observed that the effects of electricity
are in many instances rit mechanical, producing local
motion like gravitation, and therefore a proper subject. of
mathematical investigation. The establishment of electrical
science on such principles has been attempted by several :
in the opinion of the ingenious editor of the Supplement

* Copied by permission from the records of the society,

~. Vor. XVII. No. 66. G to
November 1803.

8 On the Franklinian Theory

to the Ency clopzedia Britannica, Mr. AZpinus and his fol-
lowers, Messrs. Cavendish and Coulomb, have framed &
perspicuous and demonstrable theory. The work of Epi-
nus [ have not yet been able to procure; but, perhaps, at
some future period I may be tempted to offer to the society
a seneral view of the AZpmian theory, combined with the
illustrations of hig disciples.

I have undertaken on the present occasion to exhibit a
succinct but, 1 trust, an intelligible view of that theory,
respecting the operations of the elcetric fluid, which
ascribes all electrical phenomena to the passage of this fluid
from one body to another, disturbing from various causes
that equilibrium which it is the constant tendency of nature
to preserve, producing an increase or diminution of quan-
tity, and a consequent effort to recover its original state:
a theory which, though not originating with Dr. Franklin,
owes its present adoption and celebrity to the discoveries
and illustrations of that ingenious electrician. The redun-
dancy and deficiency of the electric fluid form the corner
stone of Dr. Franklin’s theory ; and the- greatest part of
what has been since added is a more distinct explanation of
the mode of action by which such redundancy and defi-
ciency produce the observed phenomena, i shall waive for
the present any examination into the nature of electricity
in the abstract, and assume its materiality asa subtile and
most commonly an invisible fluid, which, in certain cases,
becomes obvious to our senses ; sometimes amusing us by
the singularity of its action ; at ‘other times, by its stupen-
dous effects, evincing itself one of the most powerful agents
in nature.

In order to place the advantages and defects of this theory
in the most perspicuous point of view, I shali endcavour
to arrange the subject under a few general heads or propo-
sitions ; “by which means we shall be enabled to cxamine
with more facility the dependence and connection of these
propositions with each other, and the degree of proof by
whieh they are individually and unite dly supported ; but
before we enter more particularly upon this examination it
will be proper to premise a few observations respecting the
terms in common use.

The term electricity is used too often in a vague and in-
definite sense, sometimes for the fluid or cause of action,
and at others for its perceptible effects : there is no single
word yet intreduced which bears the same relation to elec-
tricity as caloric to heat ; and at appears, at LB esent, most

1 philo«

of Electricity. 99

philosophical to apply the electric fluid as the cause or
power, and elcctricity to the effect.

Electricity is found to be of two kinds; one produced
by the excitation of glass, and formerly called vitreous: the
other by the excitation of resin, and called resinous :—
whether we impute these different phenomena to the action
of one or of two fluids, it is convenient to adopt some terms
which shal] distinguish these different states, if of one
fluid; or the different fluids if two; as a mean of such
distinction, the terms positive and negative may be safely
acquiesced in by all parties, without any precise definition
of the sense in which they ought to be received. The ad-
herents of Dr. Franklin consider positive as denoting re-
dundancy,—and negative, deficiency.

When electrical appearances, viz. the attraction of light
bodies or sparks, are induced by friction upon any body,
such body is said to be excited.

Electricity may be produced four ways :—1. Friction; 2.
Heating and cooling, as is particularly remarkable in the
tourmalin ; 3. Melting, or pouring one melted substance
into another ; 4. Evaporation: perhaps all these modes may
be justly deemed mechanical, and resolve themselves into
‘friction. When electricity is communicated from an excited
electric to another body, that body is said to be electrified.
I shall first state the series of propositions which I conceivé
comprises the most prominent and leading features of the
Franklinian theory ; and shall then consider them sepa-
rately, adverting to the proofs by which they are supported,

Prop.i1. That the phenomena of clectricity are impu-
table to the operations of one fluid, peculiar in its nature
and properties; generally invisible; extremely subtile and
elastic ; universally and plentifully diffused through the at-
mosphere and other terrestrial substances.

Prop. 2. That the particles of which this fluid is com-
posed have a strong attraction to other matter, and a strong
repulsion between themselves.

Prop. 2, That this fluid, pursuant to the general law of
hydrostatics, will, in a state of rest, be uniformly diffused
in proportion to the capacity of bodies, and in this state of
uniform distribution will produce no effect cognizable by
our senses; but that this state of equilibrium is frequently,
and may easily he, disturbed by natural or artificial causes,

Prop. 4. That this fluid moves with various degrees of
facility through the pores of different kinds of matter in
a certain class of bodies which are capable of transmitting
phis fluid with facility,.and for that reason called conduc-

: iQ tors,

106 On the Franklinian Theory

tors, such as metals, water, &c., it moves without any per-
ceivable obstruction; but that in another class denominated
electrics, such as class, sealing-wax, &c. which on frictior

produce signs of clectricity, it either moves with extreme:

difficulty, or is entirely immoveable.

Prop. 5. That though electrics. are subdivided into two
classes :—1. Glass, &e. which on excitation have a general
tendency to emit the electric fluid by disturbing the equili-
brium, collecting it, by means of the rubber, from the
surrounding bodies and conveying it to some other body,
producing the negative or minus state in those bodies, and
the Bees or plus state in the body to which it is so con-
veyed: 2. Resin, sulphur, &c. whose effects are precisely
the reverse of the other class, having a general tendency on
excitation to receive the electric fluid from any body with
which it is immediately connected, producing a negative
state in that body, and, by transmission through the rubber,
a positive state in the surrounding bodies—yet that this af-
joie no presumption of the existence of more than a single
fluid.

Prop. 6. That any excited electric is capable of com-
municating, by contact with other bodies, an electricity si-
milar to its own; and by proximity without contact, of in-
ducing an opposite state of electricity without losing any
part of its own possessions.

Prop. 7. ‘That the two different states of positive and
negative electricity may be easily and universally distin-
guished from each other by certain constant and invariable
indications.

Prop. 8. That to electrify a body, the natural or propor-
tionate quantity of this fluid must either be augmented or
lessened in that body, and that the positive state “consists in
an accumulation or excess of electric fluid; and the nega-
tive state in a diminution or deficiency of natural quan-
tity.

‘Let us now proceed to examine separately the different
assertions comprehended in the above propositions.

The first proposition comprises three positions respecting
the phzenomena of electricity, which are not immediately
obvious: that they are imputable to one fluid, elastic, and
universally diffused. Besides the want of simplicity which
characterizes the hypothesis of two fluids, it does not ap-
pear to me that any advantage is obtained by it, or that the
“most perplexing facts are more satisfactorily explained.
‘Two fluids existing in chemical combination could not so
easily be separated by causes strictly mechanical: the mere

act

*of Electricity. 101

act of breaking a stick of sealing-wax will produce the two
contrary electricities in the two contiguous extremities: if,
two different substances be rubbed together when insulated;
unless the conducting powers of these substances be pre-
cisely similar, they will exhibit opposite signs of electricity:
the mere contact between two bodies in different states pro-
duces an apparent equilibrium, and cach ceases to be cha-
racterized by any peculiar properties—Another circum-
stance which renders the theory of two fluids improbable
is, that the quality produced depends not only en the na-
ture of the electric, but on that of the rubher. Those
electrics which with some rubbers produce positive, with
others produce negative electricity ; and almost every elec-
tric may be made to produce, at pleasure, either positive or
negative electricity by the adaptation of proper rubbers.
The visible electric atmosphere may be adduced, as another
proof, in favour ef the homogeneity of the electric fuid.
#f a ball, at the termination of a brass rod whose upper
end is connected with the prime conductor, be inserted in
an exhausted receiver at a sufficient distance from another
ball to prevent a spark from passing between them, the
upper ball will have a lucid atmosphere extending itself
towards the lower ball, while the latter is destitute ef any
such appearance. If the upper ball be kept negatively elee-
trified by connecting it with the rubber instead of the prime
conductor, the effects will be reversed, and the lower ball
distinguished by a lucid atmosphere: thus we have an
ocular demonstration of the unity of the fluid; for, if there
were two fluids, both should have atmospheres : underthese
various considerations I think we may be justified in ascribing
all electrical appearances to the action of a single fluid.

With respect to the elasticity of this fluid, [ much doubt
whether it is susceptible of proof: as, however, its elasti-
city 1s inferred from its repulsive property, it will come
under our notice in the next proposition.

The universal diffusion of this fluid may be presumed
from our experience : no place kas yet been found where,
by the usual means of excitation, electricity cannot be ob-
tained; and no reason can be assigned for any partial ot
focal confinement when moisture and other conductors are
at hand to convey it over the whole earth. It will on the
present oecasion be superfluous to examine the identity
of lightning and electricity ; it will be sufficient to observe
that, by the proper management of the electrical kite, it
may at alj times be collected from the atmosphere.

G 3 The

102 On the Franklinian Theory

The second proposition contains two positions: the ate
traction of this fluid.to other matter, and the repulsive ac-
tion between its particles. That cxcited electrics will ine
fluence light bodies at a considerable distance, by attracting
such towards them, is a fact too common to be controverted ;
this property of attraction dees not appear to be the result
of any affinity between the electric fluid ‘and matter in ge-
neral, but to proceed from its tendency to equilibrium, and
its disposition or power to make use of other substances as
common carriers to restore it ; for light substances insulated
cannot act in this capacity, and will not be attracted by the
conductor.

The repulsive action of the particles of the electric fluid
between themselves is a question involved in considerable
difficulty : the experiments in an exhausted receiver do not
indicate any analogy to air or other elastic fluids; for, in-
stead of spreading wider and evincing its elasticity in pro-
portion as the resistance is diminished, the fluid passes in
an uninterrupted stream. There are, however, other cir-
cumstances which favour a repulsive quality. Thus, light
bodies after they become saturated are driven off: if a con-
ductor be brought near an excited cylinder, yet too distant
to receive a spark, and an index be placed at each end and
in the middle, the near end will be found negative, the re-
mote end positive, and the middle neuter,—proving that a
portion of electric matter has been driven off, by the action
of the excited cylinder, from the nearer to the remoter end;
and if a conducting body be presented to the remoter end
a spark may be obtained, and on removing the cylinder the
whole conductor will be found in a minus or negative state :
this repulsive quality is, too, much more subtile than the
fluid, and can act like gravitation, through substances which
the fluid itself is unable to penetrate.

The repulsion between two pith balls negatively electrified
has received many mysterious solutions, none of which, as
far as I am acquainted, are at all satisfactory. Without en-
tering into any obscute inquiry about repulsive qualities,
may we not refer the divergence of two pith balls, both in
cases of positive and negative electricity, to one simple and
general principle of attraction? When two pith balls are
artificially surcharged with the electric fluid, its endeavour
to escape, or its attraction to the surrounding particles float-
ing in the atmosphere, would impel the balls to expose the
utmost extent of their surface to discharge the superfluous
quantity ; and as the most contiguous particles become sa-

turated,

—<—SaE-

of Electricity. 103

turated, the balls will diverge, to find fresh particles capable
of relieving them, in exact proportion to the degree of their
charge. ‘Tbe same reasoning m an inverted order applies
to the negative divergency: the particles immediately con-
tiguous are deprived of their natural share of the electiic
fluid to restore the equilibrium; and in proportion as these
are insufficient to supply the demand, the balls wiil diverge
to obtain it from the next and succeeding ranges of parti-
cles. The air is probably a very good electric; and as no
actual and continuous communication subsists between the
heterogeneous conducting particles floating in the atmo-
sphere, the transmission of the electric fluid to and from
the balls, by a conveyance between such conducting but
insulated substances, must be too slow and gradual to pre-
vent the divergency alluded to. This hypothesis seems (I
mean to myself) both simple and probable: I have en-
deavoured to illustrate by a figure the detail of this diver.
gency.

Let A,B, (fig. 1. Plate IJI.) represent two pith balls sus-
pended from a point C by the threads AFC, BGC, and let
the semicircles concentric to each represent particles floating
in the atmosphere: the mutual attraction between these par-
ticles and the electric fluid contained in the balls A,B, when
positively electrified, will draw the ball A from the ball B
towards « in the line AD; and, when a particles are satu-
rated, to 1, c,d, e,f, g,h, successively in the ratio of the
charge till the redundant quantity is discharged, or, as may
be supposed the common case, till the powers of attraction
and gravitation are balanced, and the balls rest in equilibrio.
In the same manner and upon the same principles B will
recede to P, and both balls will cease to recede whenever
their gravity balances the attractive power between the fluid
and the atmosphere; in the same manner, in the case of
negative electricity both balls require an additional partion,
and, unable to obtain a sufficient quantity from a, 7, traverse
successively to h,p, till the equilibrium of the fluid is re-
stored, or a balance produced between the attractive and
gravitating powers, ea

The third proposition respects the inaction of the elec-
tric fluid in a state of uniform diffusion, and the facility
with which its natura] equilibrium is destroyed. The first
position is supported by the general analogy of fluids ; all
of which have a tendency to difluse themselves in confor-
inity to some general laws, and at a certain period become
stationary, producing no cognizable effects. We have
every reason to belicye that the clectric fluid, as well as ca-

G4 loric,

104 On the Franklinian Theory

loric, is always present in greater or smaller quantities in
the composition of bodies, and we have a right to conclude
that when its existence is not manifested by its action it
must be in a.comparative state, at least, of rest and uni-
form diffusion, since otherwise its passage would be indi-
cated by external signs or sensations.

The facility with which the equilibrium is destroyed is
very striking; the fracture of sealing-wax, the fall of me-
tallic powders, the mere operation of pressure, are suffi-
cient for this purpose. Mr. Adpinus pressed two plates of
glass close together :—when separated and insulated, each
acquired a strong electricity, one positive, the other nega-
tive; and upon reunion, the electricity of both disappeared; -
it is obvious that these modes are inferior soris of excita-
tion; but it is difficult, if not impessible, to offer any so-
lution how excitation produces these effects: the means
seem to paint out a cause merely mechanical, but the pre-
sence of oxygen for some reason seems from experiment
to be requisite for their preduction. It is remarkable that
heat destroys the power of excitation, and dry cold aug-
ments It,

The fourth proposition is a very important one, and. upon
which a large proportion of electrical science depends—I
mean the distinction between conductors and electrics—in
which it is assumed, that in conducting substances the elec-
tric fluid moves without obstruction ; and in electrics has -
a very slow and difficult, if any, passage. When we speak
hypothetically of conductors and electrics, we suppose them
to be perfect in their kind, but practically we are ignorant
of any such perfection, In metals which approach the
nearest to excellence, as conducting substances, there is
often a very obvious resistance to the passage of the fluid,
which is particularly remarkable in the destruction of small
wires by the charge of a battery, and the heating of their
substance even to redness and fusion; though the most ac-
curate experiments have been hitherto insufficient to detect
any delay af motion by such resistance, or to perceive the
Japse of any the least time during its passage for several
miles, It has been much controverted whether the fluid is
conveyed along the surface or through the substance of con-
ductors ; but it does not appear to be a point of much con-
sequence, or which at all affects the consistency of the the-
ory. Ifa wire be coated with some electric substance,
such as wax, resin, &c. it will be found to conduct a charge
with as much facility as before; and hence it is inferred
that the fluid myst pass through the substance of the wires

3 this

rede

of Electricity. 103

this proof can hardly be deemed conclusive, since it is, at
least, doubtful whether the wire and its coating ought to be
gonsidered as in actual contact; and if not so, a fluid sa
extremely subtile nght easily pass between them. That
the fluid may be forced through the substance of wire is
more susceptible’ of proof from the instances of fusion ;
but that its tendency 1s superficial may be interred froin the
superior strength of “sparks derived from conductors of lar ge
surface, extended in length in preference to breadth, when
compared with solid eouslistox’ :—in short, it is found that
the prime conductor of an electrical machine is equally, if
not more, effectual when hollow than when solid. In
some experiments made by Dr. Priestiey, the excoriation of
metallic chains resulting from a strong discharge also de-
notes some determination towards the surface.

It a perfect electric were in our possession, this hypo-
thesis requires us to conceive of it as absolutely impermeable
to the electric fluid: but as the qualities of conducting and
non-conducting substances coalesce sometimes to a very ¢x~
traordinary degree, even in glass, which we consider the best
electric—I must state that [mean by impermeability, that
power of preventing the escape of the fluid which is pecu-
liar to electrics, which power is ascribed to the great diffi-
culty experienced by the electric fluid in obtaining admis-
sion into the pores of such bodies, and the extreme slow=
ness of its progressive motion over their surface or through
their substance. This power of confining the fluid ts proved
by the charge of a Leyden phial, by the well-known in-
stances of insulation, and by the durability of electrical
properties. Mr. Henley (Phil, Trans. vol. Ixvii,) mentions
a small bottie which retained its electricity for seventy days
after charging, and remained during that time in an open
cupboard: he had a cylinder siariahled in the duration of its
cleciricity : once, after excitation, it showed strong signs
of electricity for thirty-three days: means were repeatedly
and successfully resorted to, to remove these appearances ;
but after a short pause they constantly returned without
fresh excitation, alicrnately became stronger and weaker,
vanished and returned without any visible cause; he ob-
served that the electricity was generally weak with a fire in
the room, or the door open; during a northerly wind vigo-
rous :—the cylinder did not uniformly retain this power ; :
it would often Jose all signs of clectricity in 12 hours after
excitation ; at other times it would remain a fortnight.

The different results of communicating electricity to con-

ductors, or electrics, afford another proof of the difficult

passage

106 On the Franklinian Theory

passage the last-mentioned bodies afford to this fluid: in
the first case, it finds an easy passage to any conducting
substance presented at a convenient distance, and becomes
immediately discharged; but in the latter case, it acquires
any electricity with considerable difficulty, and, in order to
imduceé it, must be touched several times and in different
parts by an electrified body. A curious experiment of pro-
fessor Lichtenberg, of Gottingen, deserves to be cited
upon this occasion (Cavallo, 72): he first excited an elec-
tric plate, upon which he placed some metallic body of a
convenient shape, and to this he communicated an eleetri-
city contrary to the one excited : then removing the metallic
body by means of an electric, he shook some finely pow-
dered resin over the electric plate, which. fell over those
parts only which had been in contact with the metallic body,
forming radiated appearances. This description accords with
a plate excited negatively, and a body positively electrified :
but if the electricities are changed, the circumstances will
be reversed also, and the powdered resin instead of seeking
those parts touched by the metallic body will obviously
avoid them.—At first sight, no reason appeared for this
variation, since both electricities attract an unelectrified
body ; but, upon more accurate examination, Mr. Cavallo
found that the mere action of falling produced a degree of
excitation inthe powdered resin, which of course became
negatively electrified, and could in that state be attracted
only by the contrary electricity. Thus, im the first instance,
where the plate was negatively electrified and the parts in
contact with the metal positive, the powder also in a nega-
tive state attached itself to the positive :—in the latter m-
stance, the plate being positive, and the parts in contact
negative, the powder also negative would attach itself to
the plate, and avoid those parts endued with an electricity
similar to its own.

Thus far the path we have trodden does not seen encum-
bered with any serious difficulties, but the observed phae-
nomena require an addition to this hypothesis which is not
very easily explicable : in charging a Leyden phial it 1s ob-
vious, from various experiments,’ that while one side is re-
eciving the other is emittmg. Let a phial be insulated,

and the knob of a second phial placed at a short distance

from its external coating ; every spark from the prime con-
ductor to the knob of the first phial will be fellowed regu
Jarly by another spark from its outside coating to the knob
of the second phial, having to the senses all the appearance
ot a free passage through the glass: but if there er a

ree

—ee ee

of Electricity. 107
_ free passage there could be no charge, and on the contrary,
both phials are found charged; and upon this principle a
battery 1s easily constructed: hence it becomes necessary to
assume that clectrics contain a Jarge and equal quantity of
the electric fluid at all times; that no real accumulation of
quantity can take place; but that by affording an oppor-
tunity to one side for the escape of this fluid, it is possible
to transfer an equal quantity to the other, while the defi-
ciency is balanced by an occult principle of repulsion.

It is certainly very difficult to imagine the existence of a
substance capable of yielding a large supply of a peculiar
fluid, and into which an additional quantity may be poured

on one side while it is abstracted from the other, when,
at the same time, it refuses a passage to this fluid through
its pores: this, however, is presumed to be the case in elec-
tricity. Dr. Franklin once imagined that, in the process
of cooling, the middle of a glass plate or jar might become
condensed, and its particles so much concentrated, that,
while it admitted a circulation of electric fluid on its sur-
face, it refused it through its substance. Dr. Franklin as
usual reduced his conjecture to experiment, by grinding a
thick glass plate away beyond the middle, and found that it
received a charge with as much facility as before, and im-
mediately acknowledged the fallacy of this opinion, I
should feel exceedingly gratified to afford the society some
light upon this curious circumstance; but as my own con-
ceptions are involved in profound obscurity, it would be a
vain and fruitless attempt to offer a fancitul solution un-
supported by experiment or by probability.

The division between the two species of electrics is so
fully detailed in the body of the fifth proposition, that it
will be unnecessary to support it by any other consideration
than an appeal to facts which are generally known. The
construction of Mr. Nairne’s machine 1s an ingenious ex-
emplification of its truth; but with respect to the reason
which determines these bodies in one instance to receive
from, and in other circumstances to yield to, the rubber a
supply of electric fluid, we pretend not to assign any. We
have examined in the first proposition the presumption
which these phenomena afford of the existence of two fluids,
and endeayoured to show that such presumption was over-
thrown by the possibility of producing either negative or
positive phates by the adaptation of proper rubbers. The
following table of excitation 1s extracted from Encyclopedia
Britannica,

TABLE

108 On the Franklinian Theory

TABLE OF EXCITATION.

Electrical Substances. Rubber. : Quality.
Back of acat ~ Every substance - - pos.
Glass—smooth Ditto - - - - pos.
rough Silk, sulphur, or metals = - __—pos.
ditto Woollens, paper, wax, hand — neg.
Tourmalin - Amber or air blown upon it pos.
Ditto - Hand ~ - - - neg.
Hareskin - Metals, silk, leather, hand - pos.
Ditto - Fine furs - - - -~ neg.
Silk—black - Sealing-wax - - - pos.
. Skins, metals, hand - ="nes.
white - Black silk or cloth, metals - pos.
Paper, skins, hand ehh Bee.
Sealing-wax Metals - - ~ - pos.
Skins, hand, woollens - - neg.
Baked wood Silk - - - - pos.
Flannel = - - - - neg.

The sixth proposition comprises another material source
of electrical knowledge. It states, in the first place, that
an excited electric is capable of communicating, by contact
or by such proximity as shall permit the free passage of the

electric fluid through the air, an electricity producing upon °

other bodies precisely the same effects as such excited elec-
tric. From this principle is derived the utility of what is
called the prime conductor of an electrical machine. This
conductor receives, and retains by its insulation, the electric
fluid from the excited cylinder, which by this. means we
have the advantage of obtaining in a more powerful and
concentrated state, since by its facility of transmission over
the whole surface of such conductor the quantity collected
from its various points, on presenting to it another con-
ducting substance, passes off in a single spark, not in mi-
nute portions as it was received. This proposition states
in the second place, that an excited electric, whose position
is such with respect to another body that no spark or other
passage of the fluid can take place, will induce upon that
body an opposite state of electricity. If an excited tube be
brought near any substance communicating with the ground
(but prepared for insulation), this substance when insulated
will be found to indicate the negative state of electricity:
if, on the contrary, an excited stick of sealing-wax be pre-
sented, the positive stzie will be induced. This cireum-
stance appears to be owing to the repulsive quatities imputed
to the electric fluid, so often nviiced in the course of our
inquiry: the fluid in the excited tube is supposed to repel

a quantity

Shine ices

a

of Electricity. 109

“ quantity of the fluid residing in the substance to which it
is presented, and to drive it off into the earth, in the same
manner as the fluid in an insulated conductor is repelled
from the nearest to the remotest end by the action of a
machine, as we have attempted to prove under the second
proposition; in this situation the substance mentioned will
have Jess than its natural share, and of course indicate ne-
gative electricity. If we reverse the picture, the excited
wax, by its opposite qualities, enables the substance to re-
ceive from the earth an additional quantity, which under
insulation appears in the form of positive electricity.

The seventh proposition assumes an universal and uniform

distinction between the two states of electricity. If no

means are discoverable by which these states can be ascer-
tained, it is sufficiently obvious that all reasoning respect-
ing their particular situations and circumstances must be
vague and nugatory: the certainty and facility of this di-
stinction 1s an essential prop to the whole theory ; let us
therefore examine evidence. The proofs of this distinction
are referable to two classes : one derived from the appearances
of electric light ; the other from the phenomena of attraction
and repulsion. - If a point be presented to the insulated
rubber of a machine, which by Proposition 5. receives the
fluid from such point, a diverging luminous stream will
become apparent, which resembles a pencil of rays centring
at the point, and darting through the air towards the rubber
with a crackling noise, conformably to the expectations we,
should form of the emission of a fluid resisted equally in its
motion by the surrounding atmosphere: but if the needle
be transferred in contact with the rubber, its point out-
wards, which by Proposition 5. then becomes the recipient
instead of emitting the electric fluid, the appearance will
be changed: when the fluid is collected from the circum-
jacent air towards a point, it is natural to conceive it slowly
and invisibly percolating from all parts in an equal propor-
tion, till it approaches sufficiently near to break through the
intermediate space ; and as this space will be equal on every
side, the negative electricity will become visible in the form
of a steady, luminous globule on the point, accompanied
with little noise: and this is consonant with experience,
The different effects of the two electricities may be adyan-
tageously observed by receiving the stream upon the flat
ie of a picce of paper: a strong plus stream forms a beau-
tiful star about four inches in diameter, consisting of very
distinct radii not ramified ; the minus stream forms no star,

while many pointed brushes centre towards the paper (Ca~
vallo),

110 On the Franklinian Theory

vallo). The appearances in an exhausted receiver, men-

tioned under Proposition 1. may be adduced as additional —

proofs. Mr. Cavallo mentions a curious though delicate
experiment as a further corroboration. After moistening
the outside of a small phial he charged it at the prime con-
ductor, and while the machine is acting a beautiful brush
becomes visible, turning downwards towards the outside
coating: if the outside be charged positive, the brush will
appear directing its course inwards, The variation in the
sensations of receiving a spark affords another collateral tes-
timony to these distinctions, the negative sparks being much
more pungent than the positive. The repulsion of two pith
balls, or gold leaf, connected with the known property of
certain substances to produce on excitation the same clec-
trical quality, affords another and a more delicate and useful
means of detecting minuter portions. If an electrometer
be brought into contact with any electrified body, the balls
or leaf will immediately separate; but we wish to ascertain
with which electricity: upon exciting a piece of sealing-
wax and presenting it to the instrument, its divergency will
either increase or diminish; if it increases, it may be con-
cluded similar to that of the excited substance ; if it con-
verges, the contrary. If you are desirous to obtain still
more accuracy of examination to determine the quality,
electrify two similar electrometers, one with some excited
body, the other with the body you wish to examine, till
the balls indicate equal degrees of divergency: then bring
together the two electrometers: if they repel, their clectris
city may be deemed similar ; if they attract, opposite.

The concurrence therefore of these two modes of exa-
mination by clectric light and electric attraction and repul-
sion, if uniform and invariable, as they are asserted to be,
affords a satisfactory criterion of the quality.

We are now arrived at the cighth and last proposition,
which states in what the qualities of positive and negative
electricity consist, viz. in accumulation and deficiency. It
has been objected, and I think with some degree of justice,
that this position is wholly hypothetical; that no direct and
unequivocal proof can be adduced; and that the arguments
commonly urged in its support are included in what logi-
cians denominate a vicious circle. Thus it is said a body
positively electrified will attract another body negatively
electrified, because the one is redundant, the other is defi-
cient. But how is this known? They attract each other.
Again, in charging a phial, there is as constant a stream of
clectric fluid frém the outside coating as from the condyctor

; to

of Electricity. 11t

to the inside; whence it follows, that while the outside has

-too little, the inside has too much. Why so? Because the

glass is impermeable. How is that proved? Because in
the experiment above recited the fluid is accumulated on
one side, while it is abstracted on the other. It is evident
that under this representation every argument returns into
itself, and is merely a play upon terms. I shall however
endeavour to show that this statement is neither perfectly
candid nor correct, and that the opinion alluded to is sup-
ported by more probability than these objectors are willing
to admit.

In many instances we can form conclusions only from
the effects. If two basons separated by a mound were filled
with water, the pressure on all sides being equal, the mound
would be likely to maintain its situation. If we suppose
one full and the other empty, with a slight communication
between them, the effort to restore the level would endanger
the safety of the mound; and if such mound were destroyed,

‘ we should instantly conclude that it was occasioned by an

accumulation of water on one side and a deficiency on the
other. May we not extend the analogy to the electric fluid?
it becomes visible only by the air’s resistance to its passage;
and if its effects are similar to those of water, may we not
impute it to the same cause? By the impervious nature of
those substances called electrics we are enabled to produce
a change, which by effects similar to those above alluded to
induces the conclusion, that they are occasioned by an ac-
cumulation of the fluid on one side, and its subsequent ef-
forts to restore an equilibrium. If the fluid as it entered
on one side passed through to the other, no change could
be effected in the glass: if the glass plate be too thin, and
the charge too high, the fluid will force a passage, leaving
a small hole or bur in the glass, sometimes cracking the
phial all round, and in either case incapacitating it from
receiving another charge. It is singular, in the use of resin
as a cement to unite the coating and the glass, the phial
will not receive the least charge without forcing such a pase
sage.

The easy solution of the phenomena of the Leyden phiaj
on the Franklinian hypothesis has materially contributed te
its reputation, Dr. Franklin proved experimentally that
when a phial is charged, one side has lost exactly what the
other has acquired : taking a charged phial, he observed, that
when he attorded the fluid on the positive side. an oppor-
tunity to escape, the other side became disposed to receive,
and would attract any light body: by insulating his rubber

he

112 On the Franklinian Theory of Electricity.

he found that the phial would not receive a charge, becatise
no fiuid could be collected; and by insulating the phial he
found the same result, because no opportunity of escape
was afforded to the fluid on the outside; but by forming a
communication between the inside and outside cuatings the
phial was charged with ease: in this case it appeared evi-
dent that the fluid residing in the outside had been trans-
ferred by the action of the machine to the inside: thus it
appears that positive and negative electricity are msepara-
ble, have a constant tendency to produce and preserve each
other, and the increase or decrease of power on either sur-
face of a plate of glass must be regulated by the increase or
decrease of the contrary power on the opposite side. In
charging positively no gradual addition of electric matter
can be made to one side without a proper conveyance for
an equal quantity to pass off on the other side, and in its
gradual discharge none can be taken from the positive side
without affordmg the negative side an opportunity of ob-
taining an equal quantity. The experiments of Mr. Brookes
have been supposed to militate against this opinion ; but
they seem more properly to confirm it, allowing some de-
eree of limitation to the general proposition: he found on
charging an insulated phial, by means of a pointed wire,
that in the act of charging both sides indicated positive
electricity; by the theory the electric fluid is driven off from
the external surface by the repulsive action of the positive
electricity on the internal side of the phial, and by the con-
finement of insulation will be constrained to pass gradually
through the point, of course producing the effect of accu-
mulation. You will probably recollect, that during the last
sessions your experimental committee repeated these expe-
riments with some additional circumstances ; and you will
remember, that when. the phial was not insulated the fluid
seemed to pass off instantly ; and the outside, even during
the act of charging, always indicated the negative electri-
city. The most serious objection is derived trom the dif-
ficulty of conceiving how a fluid incapable of percolating
the pores of glass can act through the same pores by a
peculiar occult repulsive quality: but when we consider
the mysterious qualities of gravitation, of magnetism, and
even of fluids, whose disposition to rise te the same level is
equally unaccountable, we shall feel obliged to acknowledge
that this quality affords no rational presumption against the
truth of the theory. After all, whatever judgment we form

of the general principle, its application in various instances:

will be insufficient to explain the obseryed phenomena,
: Mr.

(atom

On the Motion of Bodies affected ly Friction. 113

Mr. Cavallo bas candidly acknowledged the difficulty of
reconciling yarious properties of charged electrics with any
received theory. Where; for instance, does the charge re-
side? Not in the ceating, as may satisfactorily be showns
if-in the glass, and the fluid can penetrate any the smallest
portion, a glass might be made so thin that the fluid would
freely peryade-its substance; but a. glass ball ;4,th of an
inch thick will receive a powerful charge. The hypothesis
still remains incumbered with numerous difficulties ; and it
must be left to future investigation to determine whether
it shall be wholly rejected, or whether subsequent discove-
ries may enable us to apply the-foregoing principles with
more certainty and success.

XIV. On the Mction of Bodies affected ly Friction. By the
Rev. SaAMuEL Vince, A. M. of Cambridge. —Communi=
cated by ANTHONY SHEPHERD, D. D. F. R.S. Plumian
Professor of Astronomy and Experimental Philosophy at
Cambridge. Read November 25, 1784:

[Concluded from p. 58.]

PROPOSITION II;

LLET the body te projected on an horizontal plane LM
(fig. 3.) witha given velocity, to determine the space through
which the body will move lefore it stops, or before its motion
becomes uniform.

Case I.—1. Suppose the body to have no rotatory mo-
tion when it begins to move; and let a = the velocity of
projection per second measured in feet, and let the retarding
force of the friction of the body measured by the velocity
of the body which it can destroy in one second of time, be
determined by experiment and called F, and let x be the
space through which the body would move by the tume its
motion was ali destroyed when projected with the velocity
a, and retarded by a force F; then, from the principles of

uniformly retarded motion, x = and if ¢ = time of de-

az
2 #

scribing that space, we have ¢ She and hence the space

2 , Vale 2a—F ents
described in the first second of time = ae Now it is

manifest that when the rotatory motion of the body about its
axis is equal to its progressive motion, the point @ will be
carried backwards by the Jormer motion as much as it is

Vou. XVII, No. 66, 1 carried

f14 Onthe Motion of Bodies affected by Friction.

carried forwards by the latter; consequently the point of
contact of the body with the plane will then have no mo-
tion in the direction of the plane, and hence the frictiom
will at that instant cease, and the body will continue to ro/f
on uniformly without sliding with the velocity which it has
at that point. Put therefore x = the space described from
the commencement of the motion til} it becomes uniform,
then the body being uniformly retarded, the spaces fron
the end of the motion vary as the squares of the velocities,
ae. : a?
hence SF” @ iG: 15 FF}: ae
square of the progressive velocity when the motion becomes
uniform ; therefore the velocity destroyed by friction = a —

/ a? —2F x; hence, as the velocity generated or destroyed
im the same time is in proportion to the force, we have

2:3: a — @hs =

—__—_—__- ra
by Core 2. Prop. lees = ra ::a—fa?—2Fx i — xX
7S

av q? —2Fx the velocity of the circumference ef g ge~

nerated about the center, consequently Va? —2Fz= ux

Ts

a~WV a? —2F 2, and hence xs = mst BPs MPO A ae.
as? x 2F
space which the body deserzbes before the motion becomes
uniform.
g. If we substitute this value of z into the expression for

. Tra ’ .
the velocity, we shall have a x 7 for the velocity of the

body when its motion becomes eniform ; hence therefore it
appears that the velocity of the bedy, when the friction
ceases, will be the same whatever be the quantity of the
friction. H the body be the circumference of a circle, it
will always lose half the velocity before its motion becomes
uniform.

Casr H.—1. Let the body, besides having a progressive
velocity in the direction LM (fig. 3.) have also a rotatory
motion about its center in the direction g fe, and let v re-
present the initial velocity of any point of the circumference
about the center, and suppose it first to be less than a; then
friction being a uniformly retarding force, no alteration of
the velocity of the point of contact of the body upon the
plane can affect the quantity of friction ; hence the pro-
pressive velocity of the body will be the same as before, and
consequently the rotatory velocity generated by frietton will
also be the same; to which if we add the velocity about the

center

On the Motion of Bodies affected by Friction. 115
center at the beginning of the motion, we shall have

. Ta
the whole rotatory motion; hence, therefore, v + — x
rs

ik —— —— ——- %
a+Va@—2Fxz= /a—2FR, consequently x =
—— 3

a*xas*’—uxrstaxra
2EF x ast

motion becomes uniform.

2. If this value of x be substituted into the expression

Bi Ty Sit (LK Ti dine
ior the Ver

the space described before the

for the velocity, we shall have
as

lecity when the friction ceases.

3. If v =a, then x = 9, and hence the body will con-
tinue to move uniformly with the first velocity.

4. If vu be greater than a, then the rotatory motion of
the point a on the plane being greater than its progressive
motion and in a contrary direction, the absolute motion of
the point a upon the plane will be in the direction ML, and
consequently friction will now act in the direction LM in
which the body moves, and therefore wil! accelerate the
progressive and retard the rotatory motion ; hence it appears
that the progressive motion of a tide may be ACCELERATED
ly friction. Now to determine the space described before
the motion becomes uniform, we may observe that as the
progressive motion of the body is now accelerated, the ve-

locity after it has described any space x will be = Va +9F z,
hence the velocity acquired = Vai+eFz— a, and con-

—_—

sequently the rotatory velocity destroyed — x Va? +2Fz—a,

Ta DD ——~—~—) =
hence eas % Va?+2Fx—a= /a? +2F2, there-
;

2

rsxvu+raxa —a’? xas? :
= ——- - the space required.
fore x 2K x as? P q j
5. If a=. or the body be placed upon the plane with-
: : T'S? XV
out any progressive velocity, then s = ———.,
a RTETS*? Ys 2Fxas?

Case III.—1. Let the given rotatory motion be in the
direction g ef; then as the friction must in this case always
act in the direction ML, it must continually tend to destroy
both the progressive and rotatory motion. Now as the ve-
locity destroyed in the same time is in proportion to the re-
tarding force, and the force which retards the rotatory is to
the furce which retards the progressive velocity by Cor. 2.
Prop. f. as ra : rs, therefore if v be to aasra is tors,

H 2 then

116 Onthe Motion of Bodies affected by Friction.

then the retarding forces being in proportion to the veleci-
ties, both motions will be destroyed together, and conse-
quently the body, after describing a certain space, will rest ;
which space, being that described by the body uniformly
retarded by the force F, will, from what was proved in

Case I. be equal to “..
2
2. If w bears a greater proportion to a than ra does to

ys, it is manifest that the rotatory motion will not be all
destroyed when the progressive is ; consequently the body,

after it has described the space > will return back in the’

direction ML; for the progressive motion beimg then de-
stroyed, and the rotatory motion still continuing in the
direction g e f, will cause the body to return with an ac-
eelerative velocity until the friction ceases by the body’s
beginning to roll, after which it will move on'uniformly.

Now to determine the space described before this happens,

TUX a :
‘we havers : va :3 a: the rotatory velocity de~-
Ts
Bratt e! raxa
stroyed when the progressive is all lost; hencev — =
> : rs

DT So ON oT

== the rotatory velocity at that time, which
7S

being substituted for v in the last article of Case II. gives
V+trs—axT Ps

ER Sass
becomes uniform.

3. If v has a less proportion to a than ra has tors, it
is manifest that the roéatory motion will be destroyed before
the progressive; in which case a rotatory motion will be
gencrated in a contrary direction until the two motions be-
come equal, when the friction will instantly cease, and the
body will then move on uniformly. Nowra:rsi:u:
v x $ :

ra

for the space described before the motion

the progressive velocity destroyed when the rotatory

: ox Tis ax Ti —— Vek ar os

yelocity ceases, hence a — —~/= ——— = pro~
Te ra

eressive velocity when it begins its rotatory motion

in a contrary direction: substitute therefore this quan-

tity fora in the expression for x in Case I. and we have

2

rst¢-+2roxX TaXaXTa—vUXFS
as? xar?x2FP

after the rotatory motion ceases before the motion of the

body becomes uniform. Now.to determine the space de-

scribed

for the space described

On the Motion of Bodtes affected ly Friction. 117

scribed before the rotatory motion was all destroyed, we
have (as the space from the end of a uniformly retarded

motion yaries as the square of the velocity) a2 : a
@xra—vxrs axrTra—vxrs

raz Q2EF x ra?

eel

OAL Muh DK. TiS 2avX7raX7Ts—v? x rs?
2F 2F x ra? ee 2F x ra?
pace described when the rotatory motion was all destroyed,

2

2

-

= the

v7)

Ts*-Irsxraxax ar—v SC S77 2GVxX%7TAaXTs—v? x7rs?t
08? Kare DE i DE MT ad

= the whole space described by the body before its motion
becomes uniform.

hence

DEFINITION.

The CENTER of FRICTION is that point in the base of a
body on which it revolves, into which if the whole surface
of the base, and the mass of the body were collected, and
made to revolve about the center of the base of the given body,
the angular velocity destroyed by its friction would-be equal
to the angular velocity destroyed in the given body by its
Jrwtion in the same time.

PROPOSITION III.
To find the center of friction.

Let FGH (fig. 4.) be the base ef a body revolving about
its center C, and suppose abouta, b, c, &c. to be indefi-
nitely smal] parts of the base, and let A, B, C, &c, be
the corresponding parts of the solid, or the prismatic parts
having a, l, c, &c. for their bases; and P the center of
friction. Now it is manifest that the decrement of the an-
gular velocity must vary as the whole diminution of the
momentuin of rotation caused by the friction directly, and
as the whole momentum of rotation or effect of the inertia
of all the particles of the solid inversely ; the former being
employed in diminishing the angular Padsity, and the latter
in opposing that diminution by the endeavour of the par-
ticles to persevere in their motion. Hence, if the effect of
the friction varies as’ the effect of the inertia, the decre-
ments of the angular velocity in a given time will be equal.
Now as the quantity of friction (as has been proved from
experiments) docs not depend on the yelocity, the effect A

: H 3 the

118 On the Motion of Bodies affected by Friction.

the friction of the elementary parts of the base a, l, c, &c.
will be as a x aC, b x LC, c x cC, &c. also the effect of
the inertia of the corresponding parts of the body will be
as A x aC?, Bx bC2, C x cC*, &c. Now when the
whole surface of the base and mass of the bady are con-

centrated in P, the effect of the friction will be as a+b+c+
&c. x CP, and of the inertiaas A+ B+C +&c. x CP? ;
consequently a x aC +b x lC +c x cC + &c. :a+b+co4+
&c. x CP :: AxaC? +B x lC24+ C x cC?2 + &e. :
A+B+C-+ &c. x CP2; and hence
c A x aC?4+ Bx #C24-C xcC2 + &c. x a+b +c+ &e.
~axaC+bxiC+cexcC+k&e.xA+B+C + &e.
= (if S =the sum of the products of each particle into
the square of its distance from the axis of motion, T=
the sum of the products of each part of the base into its
distance from the center, s = the area of the base, ¢ = the

solid content of the body) Ae

Txt
PROPOSITION IV.
Given the velocity with which a body legins to revolve
alout the center of its base, to determine the number of re-

volutions which the body wi.l make before all its motion be
destroyed.

Let the friction, expressed by the velocity which it is able
to destroy in the body if it were projected in a right line
horizontally in one second, be determined by experiment,
and called F; and suppose the initial velocity of the center
of friction P about C to be a. Then conceiving the whole
surface of the base and mass of the body to be collected

into the point-P, and (as has been proved in Prop. II.) “

will be the space which the body so concentrated will de-
scribe before all its motion be destroyed; hence if we put
z= PC, p = the circumference of a circle whose radius is
unity, then will px = circumference described by the point
P; consequently i a = the number of revolutions re-
uired.
Cor. If the solid be a cylinder and r he the radius of its
37 2
base, then % = ra , and therefore the number of revolutions
Se 2a2
3prF
PROPOSITION

On the Motion of Bodies affected ly Friction. 119

fROPOSITION V.

To find the nature of the curve descriled by any point of
- a body affected ly friction, when it descends down any in-
clined plane.

Let ef g (fig. 5.) be the body, the points a, 7, s, as in
Prop. I. and cenceive st, rn, to be two indefinitely small
spaves described by the points s andr im the same time, and
which therefore wall represent the velocities of those points ;
but from Prep. L. the ratio of these velocities is expressed
by m x CB: ax CA, hencest : rm :: mx CB: 4x
CA. With the center7 let a cirele ve be described toach-
ing the plane LM which ts parallel to AC at the point J,
and let the radius ef this circle ‘be such that, conceiving it
to descend upon the plane LM along with the body de-
scending on CA, the point / may be at rest, or the circle
may roll without sliding. To determine which radius, pro-
duce rs to x, parallel to which draw xdy, and produce x ¢
to %; now it is manifest, that in order to answer the con-
ditions above mentioned, the velocity of the pot a must
be to the velocity of the peintr as 2 : 1, thatis, za : yx.
33 2:1, hencexzy=yr=nur. Nowzy: dt (:: ny :

. TS rs
md) :: rx: rs; thereforedt = — xey=— x nr, hence
TX Tr

rstrz

ts{=td+ds=tdtnr=— xnrtnr) = XT,
THX

Tstrx
consequently ~ BP

21:: ¢s : nr: (from whatis proved
rx

above) m x CB : a x CA; therefore a x CAx rs+a x
ax CAxrs
mX CB—axCA
the radius of the circle which rolling down the inclined
plane LM, and carrying the body with it, will give the
true ratio of its progressive to its rotatory motion, and con-
sequently that point of the circle which coincides with any
iven point of the body will, as the circle revolves upon the
Fine LM, describe the same curve as the corresponding
oint 6f the body; but as the nature of the curve Geghel
be any point of a circle revolving upena straight line is al-
ready very well known, it seems unnecessary to give the

livestigation.

By a method of reasoning, not very different, may the
nature of the curve, which 1s described by any point of a
body moving upon an horizontal plane, and affected by
friction, be determmed,

CA x rx=m-x CB xra, hence rx =

H4 XV. Copy

f 120 J

XV. Copy of a Letter to the Rev. SAMUEL VINCE, Plumian
Professor of Astronomy, Se. &c., Combridge, from
JoHn SOUTHERN, Engineer, dated Birmingham, Janu-
ary 19, 1801.* '

Sir,

AviNG read with much pleasure your paper on Friction,
published in the Philosophical Transactions, vol. Ixxv.f
I am induced to trouble you with this letter, containing
an account of a few experiments made by me some years
since on the same subject, which were suggested by your
elegant proposition, in terms equivalent to the following :
that if friction be an uniform force, a body falling by its
own weight, but resisted by friction, would nevertheless
be uniformly accelerated. If you think the account is
worthy the attention of the Royal Society, you will, per-
haps, do me the favour of presenting it to that learned
body f. Berea Oe

ACCOUNT OF SOME EXPERIMENTS ON FRICTION.

In the neighbourhood of this place there are many mills _
used for turning grindstones which have a very great velo-
city, and which, from the facility of being detached in that
state from the mill, are peculiarly adapted to ascertain, or
rather to corroborate, your proposition, and also to deter-
mine in such cases the real quantum of friction; and I
therefore availed myself of the liberty, which I readily ac-
quired, to make experiments at one of them. Before | give
an account of these, it will be useful to give a description of
the apparatus employed in making them. (See Plate IT.) §

A, (Fig. 6.) the grindstone 52} inches diameter, and 2@¢
inches thick. ©

B, its spindle (of iron).

CC, the pivots or cylindric parts of the spindle, upom
which it and the stone turned, exactly 3} mches dia-
meter.

D, the pulley (of wood) upon the edge of which a Jea-
ther strap went round, or rather half round, by which
the stone was put in motion and continued so during
pleasure, and by slipping off which the stone was de-
tached from the mill, and suffered to turn freely till
the resistance of friction on the pivots of the spindlé
and of the air stopped it.

* Communicated by the Author.

+ See the preceding article, conzinued from. our Jast number.
t Mr: Vince, approving it, did present it to the Royal Society.
§ Inserted in our last Number.

Aceount of some Experiments on Friction. 124

~E, aslight axis made of a wire, perhaps the tenth of an

inch diameter, turning with the spindle, and attached

. by a socket to the arbor of the seconds-hand of a comi-

mon clock movement (not shown in the figure), so

~ that every turn of the stone corresponded to a minute

on the dial-plate, which was so situated as to be easily
observed.

The experiments were conducted as follows : By a very
excellent watch (having a detached scapement) I was ena=
bled to call out at the expiration of every minute, and m
assistant being at his post, opposite the dial-plate of the
clotk, noted the hour and minute pointed out by it at the
instant of my calling; and, that as little time might be lost
as possible, we were both ready to observe as soon as the
stone was detached from the mill. ;

Below are stated the particulars of three experiments,
being all that were made.

First Experiment. Second Experiment. Third Experiment.
ik ORE: z [° Ze
q 2°32 ea ve hy
BG be a 12 B 18
o,fee3 {silts [8 |e ait | bibba
f jegiwe® [2 ¢)3 12 (ele {gs |2 12
a |S orgeaga [ol] § |] .8 $ oi] $ |g &
iS ates] v 4 a = 3 ° i S 5 is
rt 5 a = £ = te = te ‘ =| iB
sales. fe fs. $8 fel & lets
§ a gS slo|| 8 Pole ate ts gts
2 2/300 5/5)}] 2 “4 1.028 rf 4d |e
& [azleceecl €) 83 /S2 (8) 2 | 28 (e213
BH Jo ABE Ea Bil Go l/Asinl A lms jA = R
h. m, h. m. h..m
- 0 [12 50) : 0 | 3 25 O |11 54
250 254 257
1 5 OF og 30}} 1 7 39 28]; 1 411 33
220 226 224
4 8 40 oat 2° 117 25 28]; 2 7 55 30
186 198 194
3 j11 46) . 291; 3 2 48 26), 3 i111 9 31
" 157 172 163
4 1293 Some lag Nah air 28]| 4 11 52 oF
127 | 144 | 136
5 4 30 26)| 5 7 59 24\| 6 4 8 28
: 101 120 108
6 6 11 25:1 6 9 59 26), 6 5 56 28
76°} | 94 80
7 7 O27 24'}-7' {ile 33 26\| 7 7 16 29
52 68 51
8 8 19 ———__ 8 112 41 25), .8 Seige =
| 25 43} |J——| dt a7y
8/364/'| 8 44! at rest 9 | 1 24 |—-—]| |/8/ 55!| 8 244 at rest
Whole No.ot turns 1194) ||" 104 No. of turns 12804 :

9/36"! 1 S42at rest
| No. of turns 3293

It

122 = Account of some Experiments on Friction.

It is well known to mathematicians, that had the re-
sistances which opposed the motion of the stone been uni-
form, and the observations correct, the second diferentes,
er those contained in the fourth column of each experi-
ment, would have been the same, or a constant quantity.
This it appears was not so, and several causes can be as-
signed why they might not be so, though friction itself be
an uniform resistance: First, when the stone was making
260 or 270 turns per minute, as it was at the beginning of ,
each experiment, the minute-hand would be passing over
41 minutes on the dial-plate per second of time, and conse-
quently it was difficult to observe the precise place of the
hand. Hence it is easy to see that a variation might arise
on this account, especially when it is considered that the
moment of calling by one person, and of attention of a se-
cond, might not be simultaneous. Secondly, as the circum-
ference of the stone at the beginning of the experiments
was moving with a velocity of upwards of 60 feet per se-
cond, some resistance from the air would necessarily arise,
which would diminish as the stone revolved more slowly,
and this would create a difference in the uniformity of
resistance, and consequently in the second differences.
Thirdly, the mill being used for grinding, the principal
part of the apparatus was covered with siliceous dust; and
though the rubbing parts were protected from it as much as
possible, some particles of it might, by the shaking of the
machine, fall between the rubbing surfaces, and thus occa-
sion a variation in the resisting force at different instants.
i am the more inclined to believe this was actually the case,
from observing in the table the variation of mean resistance
in the three experiments, notwithstanding they were made
under circumstances as precisely the same as possibly could
be: for in the second experiment the stone made 135 more
turns before it came to rest than it did in the first, although
the initial velocities were not materially different; and in
the third experiment, notwithstanding the initial velocity
was greater than in the second, the whole number of revo-
lutions was 99 less.

If the second differences for each corresponding minute
of time in the three experiments be added together, and di-
vided by 3, the numbers 304, 303, 283, 284, 26, 265, 264
will be obtained for mean second differences; and had the
experiments been very numerous, I think the probability is
great that a set of means would have arisen which would
have shown a more steadily decreasing series. From these
few experiments, howeyer, it seems fair to infer, that the

resistance

Account of some Experimenis on Friction. 123

resistance is greater when the velocity is greater: but it
will shortly be seen whether this increase of resistance may
not be attributed to the air.

I will now proceed to estimate the intensity of these re-
sistances from the facts related ;

The grindstone being 524 inches diameter and 201 inches
thick, its solid contents were consequently 25% cubic feet;
the specific gravity of a piece of stone of the same kind was
accurately taken, and found to be 2.208: a cubic foot of it
would therefore weigh 138lb., and the whole grindstone
3501lb. The iron spindle and wooden pulley were by calcu-
lation 200]b., making the whole weight that was supported
by the pivots of the spindle in round numbers 3700lb.

The resistance which a particle of matter at the distance
x from its centre of motion opposes to a change of angular
motion is as x”, the resistanee being measured by a power
applied at a constant distance from the centre. In order to
find the sum of resistances of all the matter in the stone, it
is to be considered that the number of particles at the di-
stance wx is tmxx (t being = the thickness of the stone, and
m = 6,283 &c = the circumference of a circle whose ra-
dius is 1); and as the resistance of every one of these par-
ticles is, as before said, 2 the fluxion of the sum of all the
resistances = ¢mx'x whose fluent, or sum of resistances

tma* : mtr *
= when x = 7, (the radius of the stone)

If all the particles of the stone had been at the distance r
from the centre, the sum of resistances would haye been as

mtr*

the solid content x7? = 3 it is therefore evident that

the sum of resistances of all the particles of the stone is
half what it would be if every particle were at the circum-

; ee ie
ference, and had the same angular velocity: for zeae

mtr*

Bice wee

By the experiments it appeared that when the resistance
of the air might be esteemed inconsiderable (the velocity of
the stone being comparatively small), the retardation of the
velocity was about 26 turns per minute attributable to the
friction on the pivots. It may therefore be asked, What
power acting uniformly would give to half the quantity of
matter in the stone (= 1750lb.) a velocity equal-to 26
times its circumference? Twenty-six times the circumfe-
rence of the stone is about 3574 fect. Gravity would give

a velocity

194 Account of some Experiments on Friction.

avelocity = 321 x 60 = 1950 feet per second at the end
of one minute to a body falling freely, or 117000 feet per
minute; and the accelerating or retarding power being as
the velocity acquired or destroyed in a given time, we have
117000 : 3574 :: 1750 : 5,35 = the power in pounds
applied at the circumference of the stone that would ge-
nerate or destroy the velocity of 26 turns per minute.

The resistance arising from friction is not, in the expe
riments, applicd at the circumference of the stone, but at
that of the rubbing parts of the spindle, which, as before
stated, was 31 inches diameter; therefore to find the actual
resistance caused by friction, 5,25lb. is to be increased in
the inverse ratio of the diameter of the stone to that of the
pivots: hence, 3,125: 52,5':: 5,35: golb. nearly, the re-
sistance arising from the friction of 3700]1b. ef matter, or
less than one-fortieth part of the weight.

‘I purposely omit to take into account the resistances of
imertiz of the iron spindle and wooden pulley, because the
former from its centric situation, and the latter from its
lichtness, would not materially affect the conclusion.

It may now be judged of in some degree, whether the
greater resistance which appeared to retard the stone under »
greater velocities might not arise from the air. It has been
shown that the mean least and mean greatest retardations
per minute were 26 and 380% revolutions; if 26 turns be
equivalent, as shown above, to 5,35lb., at the circumfe-
fence, 302 are equivalent to 6,31]b. and the difference 96ib,
would cause this extra resistance. That a stone of the dia-
meter specified, whose sides were very roughly hewn, and
which moved in a trough nearly half its depth with a velo-
city of upwards of 60 feet per second, should meet with a
resistance from the air equal to not quite one pound weight
at its circumference, is not with me a matter of surprise,
and I have no hesitation in attributing the variations in the
mean second differences to this cause.

It will be evident, on due consideration of the facts which
‘occurred at the end of each experiment, that the resistance
was much greater im the last portion of time of cach than
in the previaus ones; and though part of this might arise
from the small velocity of the rubbing surfaces at that pe-
riod of the experiments, part might also arise from a cir+
eumstance which was obvious enough, viz. the stone being
heavier on one side of the centre than on the other, so that
the motion in the latter seconds of time was considerably
irregular. pate: ve

On the whole, I conclude that these experiments a

3 im

‘ape

On the Bite of a Snake cured ly Volatile Alkali. 128

firm yours in relation to the induction that friction is an
uniform resistance, at least where the rubbing surface
moves witha velocity of from 9 inches to 4 feet per se-
cond, and that in favourable cases it docs not exceed the
fortieth part of the pressure or weight which occasions it.

The pivots ‘of the spindles were - steeled, ran in brasses,
which together might be seven or eight inches long (say
34 or 4 mches each) , and were lubricated with mutton suet.
laid against the pivots ; and as a very gentle heat was ex-
cited by the friction the suet was softened, but by no means
ina fluid or even semi-fluid state. The necks of the spindle
had this kind of temperature when I made the experiments,
the stone having been at its usual work several hours be-
fore I began them ; ; and I, being desirous of taking them
in their common state of wvenek | made no alteration what-
ever in this respect.

When these experiments were made (Jane 1797) I hoped
that some opportanity would soon oceur of making further
ones on the same subject in the same manner, in which I
might balance the stone and prepare every circumstance
with due care: but as no such oppor tunity has since oc-
curred, I am induced to present this account to you, sit,
erounded on the few experiments as they were made.

Lam, sir, with great respect,
Your most obliged servant,
JOHN SOUTHERN.

a ee
‘

These experiments are the more worthy of notice, as
they were made on actual and heavy machinery, with con-
siderable variation of velocity of the rubbing surface, and
great spaces were rubbed over: the weight which caused
the friction being upwards of 33cwt., the velocity of the
rubbing surfaces 4 feet per second at the greatest, and the
length of surface rubbed over more than 1000 feet in each
of uwvo experiments, and not much short of that in the

other. JS.
August 4, 1803.

XVI. On the Bite of a Snake cured by Volatile Alkali. By
Davip Ramsay, M. D.

A suwner of extraordinary cures performed within the
last twenty years, in the East Indies, on persons bitten by
snakes, have been communicated to the public in Jones’s
Asiatic Researches. These were effected by eau de luce, or

by

196 On the Bite of a Snake

by volatile caustic alkali. Similar cures are recorded in

Anderson’s Recreations, as having taken place in Pondi-+
cherry in 1798 and 1799. About the same time my much
esteemed friend Mr. Peale, of Philadelphia, added a living
rattlesnake to his valuable museum, and invited physi-
cians and others to subject animals to its bite, with a view
of determining, by subsequent experiments, the compara+
tive merits of the different remedies commonly recom-
mended for obviating the effects of the bites of venomous
animals. ‘The result proved, that the volatile alkali was
entitled to a decided preference. Possessed of these facts,
I have for some years past enibraced every opportunity for
ascertaining, by experiment, how far the bites of snakes,
or the stings or bites of other venomous animals, might be
alleviated by this powerful remedy. A few cases have oc-
curred in my practice, both from the bites of snakes and
from the stings of spiders, in each of which the result
equalled the recorded beneficial effects of similar applica~
tions on the other side of our globe. The last was the case
of a negro fellow, by name Stepney, who on the 3d instant
was bitten by a rattlesnake at Health Farm, on Charleston
Neck. I was not present ; but my provisional directions
were so punctually carried into effect as to save a valuable
life, that in all probability would otherwise have been lost.
The experiment was decisive; for though no other appli-
eation than the volatile alkali was used, the most excruci-
ating agonies of the patient were speedily relieved, and a

complete cure obtained in a few days. From full conviction’

of the efficacy of the remedy, I recommend to planters, and
others exposed to the bites of snakes, to have always at
hand six or eight ounces of the strongest spirits of harts-
horn, well secured ; and in case of a person being bitten by
a snake, to give him 60 drops thereof in water, every six or
eight minutes, till his pains begin to abate, and then to
lengthen the interval between the doses‘in proportion to the
abatement of the pain. The wounded part should also be
frequently washed with the same medicine. The spirit of
hartshorn is particularly designated, because the planters
are acquainted and generally provided with this medicine,
and can command it in all seasons and places: though it is
inferior in strength, and slower 1m its effects, than strong
caustic volatile alkali, yet experience has proved that it 1s

sufficiently strong to effect a speedy and complete cure. _
Oil should not be given before or during the exhibition
of the hartshorn ; for it would weaken its effects, or com-
bine with it and make soap. That the volatile alkali, pro-
perly administered, will in a short time cure the bite of ie
snake,

=

cured by Volatile Alkali. 197

snake, or the sting of a spider, or any other venomous in-
sect, is a medical fact as well established as that the Peru-
vian bark will care an intermittent fever. There are ex-
ceptions to all general rules, and probably more to the latter
than to the former. With the exception of a few extreme
cases in which the bite proves instantly mortal, either from
the uncommon virulence of the poison, the peculiar nature
of the part to which it is applied, or the operation of fear,
the volatile alkali may be depended on to afford a certain
and speedy cure. Of this we have authentic evidence in the
books referred to above, which state cures performed in the
East Indies by means thereof, even in cases where the
poison had advanced so far that mechanical force was ne-
cessary to unlock the jaw before the medicine could be in-
troduced.

Such persons as have no access to these authorities, or
are slow to believe the records of distant events, are re-
quested, for their further satisfaction, to inform themselves
of the particulars of the cure before mentioned, as having
taken place on. Charleston Neck since the commencement
of the present month. On inquiry, they will find that the
most alarming symptoms were removed in a few hours by
the unassisted operation of this single remedy.

That volatile alkali should always succeed is not to be ex-
pected ; but in nine cases out of ten its failure, on a pro-
per examination of every circumstance, would probably be
found to arise from one or more of the following circum-
stances :—either the medicine given as volatile alkali was
spurious, or inferior in its kind, or weakened by being fre-
quently opened, or insecurely corked ; or that it had been
given in too small doses, or at too long intervals. Such
persons as design to give it a trial are requested to be mi-
nutely attentive to each of these particulars.

As the hydropbobia following the bite of a mad dog has
resisted all the remedies hitherto used far its cure, it 1s sub-
mitted to physicians whether, on principles of analogy, it
would not be well to try the effects of volatile alkali, rather
than resign a patient to his fate, or repeat the medicines
which on frequent trials have always been found unavailing?
A doubtful remedy is better than none. He who does not
do all in his power to save a life, especially one committed
to his care, is guilty of a species of murder.

I will be obliged by information of the result of any ex-
periments that may be made in consequence of this com-
munication. Davip Ramsay.

Charleston,

June 22, 1803.

XVII. Letter

esi: I

XVII. Letter id Dr. Ramsay, in consegitence of his Ol-
servations on the Bite of a Snake cured by Volatile Al-
kali... By Benjamin Barron, M. D.*

DEAR SIR,

i HAVE seen yout Observations on “ the Bite of a Snake
cured by Volatile Alkali.” I rejoice to find that you have
undertaken the investigation of a subject so important as is
the one on which you have favoured the public with the
result of your experience. I hope you will pursue the in-
qtiiry, as [ am well persuaded that we are in want of some-
thing much more efficacious as a cure of the evil effects in-
duced by the venom of the rattlesnake, and other serpents,
than any of the many vegetables which have been recom-
mended to the public mm such extravagant and unqualified
terms.

Ever since the spring of 1801 TI have paid a great deal
of attention to the effects of the venom of the rattlesnake.
f have had a number of these reptiles, both old and young;
under my immediate care, and have caused them to bite
many and various species of animals, with the view to col-
lect materials for a history of the poison. My experiments
have satisfied me, that the venom of the rattlesnake is one
of the most deleterious substances with which we are a¢-
quainted. In many instances, the effects of the poison
were observed almost instantaneously ; and so rapid is the
progress of effects, that several of the bitten animals, such
as rabbits, dogs, &c., died in about thirty minutes. I may
add, that a few weeks ago a man died in Jersey in twenty-
seven minutes after he had been bitten by a rattlesnake.

The infirm state of my health, which compelled me te
leave the city last summer, prevented me from pursuing my
experiments as I had wished to have done; and the death
of the only remaining two of my snakes, by the cold of the
succeeding winter, has put it out of my ‘power to do any
thing on the subject this summer. But I shall not neglect
to resume the inquiry next spring, as I have the promise of
a number of living snakes; and I shall take great pleasure in
making you early acquainted with the result of my experi-
inents.

One of the objects of my inquiry is the discovery of the
best means of preventing or of curing the disease occasioned.

. . o .
by the bite of the rattlesnake, and others of our venomous

* Communicated by the Author.
serpents,

On the Bite of Serpent. 129

serperits, such as the copper-head, &c. I feel no disposi=
tion to exhaust any of my time in experimenting with all, or
even a twentieth part; of the many vegetables which have
been praised and employed for these purposes in different
parts of the United States. Many of these are unquestion-
ably inert, and I think I have elsewhere shown how they
have acquired their reputation *: I am far from denying
that some of the vegetables to which I allude are deserving
of a portion of the praise which has been bestowed upon
them. The seneca snake-root (polygala senega of Lin-
nus) is; without doubt, a plant of great powers; and may
be worthy of our attention as a remedy against the bite of
venomous serpents. You know that among the Indians
this plant has sustained a high repuitation in this respect.
One of itiy correspondents (Mr. Samuel Preston, of this
state,) has communicated to me a case which is worthy of
being mentioned. In the year 1798, a man, whilst he was
mowing, was bitten by a rattlesnake in the little toe of his
foot. Almost instantly he was seized with a pain in his
breast and eyes: The leg became greatly swollen; and vio-
lent symptoms of a genuine tetanus ensued. The seneca,
which was at hand, was boiled in milk, and the patient
drank large quantities of the decoction; at the same time
that the root, in the shape of a poultice, was applied to the
part immediately wounded. The medicine threw him into
a profuse perspiration; in a short time all his spasms sub-
sided, and at the end of two days he was able to return to
his occupation of mowing again:

This case, to which | have alluded in my Elements of
Botany, part iii, p. 105, is certainly an important one, as
I think it plainly shows that the seneca is a medicine well
adapted to some cases of the bite of a rattlesnake. | rather
regret that, in the work just mentioned, I should have used
the fullowing words when speaking of the medicine :—
“« Its great virtues as a remedy tor the bite of the rattle-
snake may, [ believe, be safely called in question.” I am
far, indeed, from supposing that it is an infallible medicine
or specific: on the contrary, I have not a doubt that it
would fail to effect a cure in many cases of the bites of ve-
nomous serpents. What relicf could we expect from it, or
indeed from any thing else, in cases (such as the one in
Jersey) where death was induced in less than half an hour?

I shall not omit to try the effects of the volatile alkali.
Hitherto I have not used it, because I had imagined that

* Transactions of the American Philosophical Socicty, vol, ili, no. 11.

Vor. XVIL. No. 66, J correct

130 On the Bite of Serpents.

correct experiments had nearly robbed it of all its former
reputation. It appears from the abbé Fontana’s bighly m-
teresting work on poisons, that this alkali, whether exter-
nally applied or internally exhibited, was of no use in.di-
minishing the activity of the venom of the viper, which is
so very similar to that of our rattlesnake. One quotation
from the Italian philosoplier’s work I beg leave to lay before
vou: * I had (he says) several animals, such as hens, rab-
ves guinea pigs, &c. bit in the leg, and some minutes
after made deep and extensive incisions into the wounded
parts. I washed these incisions with pure volatile alkali,
and covered the legs with linen bandages. [ got ready an
equal number of animals of the same size, and of the same
kinds, to serve as a comparison. These were likewise bit
_in the leg; but I mtither made incisions, nor applied to
them the volatile alkali. The result of twenty-four ex-
periments was not favourable to this medicine applied to
the incisions, and the violence of the disease was eyen more
considerable in the former than im the latter*.”” Uponthe
whole, Fontana is of opimion that his experiments ‘* not
only demonstrate fhe absolute inutility of, the volatile: al-
kah against the bite of the viper, when applied externally ;
but,” that “* they at the same time prove still further that
it cannot have a direct and specific operation when itis even
taken internally.” ;

I do not pretend, sir, to decide between your experience
and the experiments of Fontana. Ican, in great sincerity,
assure you that [ repose much confidence in your caution
wind accuracy in conducting medical inquiries, aud in your
candour in relating your observations. But do we not very
often ascribe effects, both good and bad, to our remedies,
which those remedics have not produced? Do not our
patients sometimes recover from violent diseases without
the aid of any medicines whatever? Does not nature (that
is, the powers or tendencies of the constitution) very fre-
quently cure a gonorrhea? Nay, dowe not find the same
powers, in some instances, suflicient to cure the malignant
disease of yellow fever?

The result of all my inquiries relative to the poison of
serpents is' Very favourable to the opinion, that the instances
of spontaneous recovery from the influence of these poisons
are numerous, Without admitting this position as a fact,
what satisfactory explanation can be offered of the many

* Treatise on the Venom of the Viper, &c, &c.—Eglish translation,
wol. ii. pages 5, 6. ;
Tecaye»ries

Analysis of Ambergris. 131

fecoveries from the bite of the rattlesnake, when the ve-
getables that were applied externally, or exhibited inter-
nally, were, if not nearly inert (mere nwlrientia), at least
endued with the most opposite powers? Thus, the bulb of
hypoxis erecta (which grows abundantly in Carolina and
other parts of the United States) is by many persons deemed
a sovereign remedy against the bite of the rattlesnake.
But this bulb, which I have often eaten, is almost as mild
and inert as boiled rice.

That an animal which has been bitten by a rattlesnake,
whose poison has induced most violent symptoms, such as
acute pain, fever, and even palsy of the extremities, shall
completely recover from these symptoms without the aid of
any medicine whatever, is a fact which is familiarly known
to me from my own experiments. ; :

Permit me to suggest to you the propriety of employing
active emetics, so as to excite full vomiting, in some of the
cases of the bites of serpents that may come under your

-eare. The very striking analogy which subsists between the
effects of the venom of the rattlesnake and: those of the
poison inducing malignant yellow fever, has led me to
suspect that emetics might be useful in the former as well
as in the latter of these cases. Fontana found the tartar
emetic useful in cases of the bite of the viper; and D. Boys,
an intelligent physician who is settled at Staunton in Vir-
ginia, informed me (in my visit to that place last summer)
that he had found emetics so managed as to excite both
puking and purging, more useful than any thing else in re-
moving the symptoms Sra from the bite of the
copper-head snake, which is not less venomous than the
rattlesnake.

Be assured of the high respect which I entertain for your
talents and, usefulness in life, and permit me to subscribe
myself, dear sir,

Your very obedient and humble servant,
and affectionate friend,

Philadelphia, BENJAMIN SMITH BARTON,
July 23d, 1803,

oe

XVIII. Analysis of Ambergris. By BourLLON-LAGRANGE.
{Concluded from p. 92.]
EXP. Vi. Alkalies unite with ambergris, and form with it
soluble soaps.
Thirty grains of ambergris with ten grains of pure potash
rg were

132 Analysis of Ambergris.

were put into a platina crucible and exposed to a gentl@
heat: the mixture fused without manifesting the presence
of ammonia: by cooling, a brownish homogeneous mass
was obtained. .

One ounce of distilled water being poured over it dis-

solved a part. This liquor was exceedingly alkaline. ,
_ The other portion not soluble remained under a soft te-
aacious form, which when warm adhered to the fingers.

A larger quantity of water being added, the whole was
dissolved. :

Caustic potash triturated some time in a mortar with

ambergris does not facilitate its solution by water. *
_ Ammonia cold has no action on it, but with the help of
heat dissolves it. The mixture gradually becomes brown,
and by evaporation gives a glutinous saponaceous matter,
similar in every thing to that obtained by potash.

Exp. VU. Fixed oils, such as that of colsa, olives, &c-
dissolve it with the help of heat ina very little time: the
solution is yellow and transparent, and by evaporation be-
comes brown.

Exp. VIII. Volatile oils also dissolve ambergris.. Those
of turpentine, savin, and hyssop, do the same. With the
help of heat the solution takes place speedily.

Evaporation gives a thick red magma which cannot be.
entirely dried, which burns on coals, emitting a thick
smoke and an odour approaching that of ambergris. Al-
cohol dissolved this substance,and acquired a golden yellow
colour: it was precipitated from it by the help of heat.

A complete solution cannot be obtained in yolatile oils
which are too old,even with the assistance of long continued
heat.

Exp. 1X. Solution by ether is very speedy even without
heat.

fixp..X. The solution of ambergris by alcohol is that
alone which can conduct to any certaim results. The con-
Stituent parts may be separated in such a manner, that by
uniting them a conypound will be obtained the characters
of which approach near to those of the compound.

One gros of ambergris being reduced to fine powder and
put into a phial, two ounces of rectified alcohol were poured
oyer it. ‘Twenty-four hours’ maceration were sufficient to
give to the alcohol a dark yellow colour. When the liquor

ad been filtered a new quantity of alcohol was added to the
undissolved part, and the solution was facilitated by ele-
vating the temperature. When the whole was: dissolved,
except.

+

Analysis of Ambergris. 138

except a small quantity of black matter, the liquor was fil-
tered still warm. It passed through clear; but by cooling
there was separated a light pale yellow substance, a part of
avhich remained attached to the sides of the vessel.

The first alcoholic tincture made cold, and that arising

from the matter precipitated, were mixed, and evaporated to-

the consistence of extract: it was of a reddish yellow co-
lour, adhered to the fingers, had an agreeable odour and
a sweet taste. The evaporation was continued to dryness :
in this state the matter with a brilliant and transparent
aspect became soft between the fingers, and burnt in the
same manner as resins. ;

The experiment was repeated, to establish in a more por
sitive manner the characters of these two substances.

For this purpose the ambergris was left, as before, to
macerate in alcohol for twenty-four hours: it was then fily
tered, and a new quantity of alcohol was added to the re-
siduum: the maceration was the same. This second
liquor was less coloured than the former. A third dose of
alcohol was poured over the undissolved part, but it was
scarcely coloured. This little action of the alcohol on the
residuum gave reason to believe that it was no longer so-
Juble in that menstruum: but I soon was convinced of the
contrary. I heated the mixture, and the whole matter was
dissolved in‘a moment. Nothing remained but about four
grains of a black powder, which was oxide of carbon. The
liquor was filtered warm, and by cooling.there was preci-
pitated a whitish yellow glutinous matter, which was sepa~
rated from the liquor. phe.

This experiment proves the possibility of separating by
‘the help of aleohol three very distinct products: the first
soluble cold, the second soluble warm, and the third inso-
luble, which is separated in the form of dust.

To establish the characters of the two first substances, the
alcoholic tincture made cold was evaporated to dryness.
_ There remained in the capsule 22 grains of a brown dry
_ matter, brilliant in the fracture, unalterable in the air, and
_awvhich became soft in a gentle heat: fifteen degrees were
sufficient to give it a tenacious ‘and glutinous consistence :
when placed on coals it was entirely volatilized. If this
experiment be made in a silver spoon, the volatilization is
effected with the same rapidity : it emits an aromatic odour,
sand leaves no carbonaceous residuum.

As I suspected that this substance might have some ana~
Jogy with the resin extracted from the propolis by C. Vau-
- 13 queling

whit

behal

134 | Analysis of Ambergris.

quelin, I made some comparative experiments with it. The
following are the points in which they differ:
Ist, It fuses much more slowly.

2d, It emits a thick odorous smoke, which in smell ap-
proaches near to that of honey. ?

3d, It swells up, and leaves a very voluminous charcoal.

In the last place, this first substance extracted from am-
bergris, which may be considered as a real resin, is soluble
in alcohol, and may be precipitated by water. This tinc-
ture reddens turnsole paper; which still proves that the al-
cohol dissolves at the same time the benzoic acid previously
found, either by burning the amber under a bell, or in treat-
ing it with lime.

Nothing now remains but to examine the product ob-
tained by alcohol warm, after the resin has been extracted
by maceration.

I have already said that there is separated from the al-
cohol by cooling, a substance which deposits itself in part,
and which adheres to the sides of the vessel.

When separated from the liquor and properly dried, it
remains light ard somewhat voluminous; it breaks and
moulders under the pressure of the finger, but soon after
it extends itself and becomes soft by the heat: it has a la-
mellated texture if left to cool slowly,

It retains between its molecule a little water and alcohol,
which are separated by keeping this substance some time in
a state of fusion. When re-fused it is much Jess white than
before, and no longer possesses the granulated texture it
exhibited. In a word, I have found in it all the properties
of adipo-cira; a substance which C. Fourcroy found in the
fat matter of dead bodies, and of which he described the

characters in a memoir printed in the eighth volume of the
Annales de Chimie.

Recapitulation.

It appears, then, that we may conclude from these expe=
riments :

1st, That ambergris is a compound substance which
burns and is entirely volatilized.

2d, That when distilled alone there is obtained from it a
liquor slightly acid, and an oil partly soluble in alcohol and
of an empyreumatic odour.

3d, That by sublimation, or the process of Scheele, ben-
zoic acid is extracted from it.

4th, That water has no action on this substance.

Sth, That

Employment of Platina in Porcelain Painting. 135

5th, That by help of the nitric acid a matter analogous
to resins mixed with adipo-cira is separated from it.

6th, That concentrated sulphuric, muriatic, and oxy-
genated muriatic acid char it without dissolving it.

7th, That witir alkalies it forms a saponaceous compound.

8th, That fixed and volatile oils, ether, and alcohol, are
the true solvents of ambergris.

gth, That alcohol affords the means of separating its con-
stituent parts in the following proportions :

Grammes,
Adipo-cira - - - 2016
Resin - - - 1°167
Benzoic acid - - 07425

Carbonaceous matter - 0°212

: 3°820

—te,

XIX. Observations on the Employment of Platina in Porce-
lain Painting. By Professor Kuarrotn, of Berlin*.

iy the course of half a century since platina was introduced
and known in Europe, the experiments made with it by
various eminent chemists seem to haye exhausted every
thing that relates to the physical and chemical properties of
this remarkable metal. The imperfect information, how-
ever, which relates to its mineralogical and natural history
seems to require further investigation, though it must at
the same time be acknowledged that our information in
this respect appears to be worthy of confidence, as the Spa-
nish government has entrusted the inspection and manage-
ment of its mines in South America to men who to 4
knowledge of mineralogy and mining unite great zeal for
the improvement of these sciences.

The real origin of platina is in all probability to be
ascribed to revolutions which have taken place in the Cor-
dilleras by volcanoes, earthquakes, and inundations; and it
is not improbable that these mountains still contain in their
interior parts entire veins of platina, the discovery of which
is perhaps reserved for future times.

At present, Peru is the only known country where pla-
tina is found, and particularly the district of Choco, where
it is collected in the valleys between the -mountains and
rivers along with the gold in small laminz, or it is ob-

¥ From Scheres’s Al/gemeines Yournal der Chemie, no. 52, 802.
tained

136 On the Employment of Platina

tained by washing the earth. When the largest grains of
gold haye been picked from the mixed mass of gold and
platina, the remaining gold js extracted by amalgamation ;
by means of which operation the platina is left behind in
the form of flat plates or scales, ‘

The deceptions formerly practised by mixing gold with
platina have induced the Spanish government to prevent the
exportation of it, and to give orders to all their servants in
that country to keep the platina by them, and to wash it
in water from time to time. But as means have been found
to detect easily and in-a certain manner the adulteration of
gold with platina, and also-to employ it for valuable pur-
poses, it is to be hoped that the Spanish government wil}
not persist in causing a prohibition so injurious to the arts
and to its own finances to be executed with the former se-
verity.

My object at present is not to enlarge on the chemical
and physical properties of platina, but only to offer a few
observations on the uses in the arts to which it has hitherto
been applied; and then to give an account of the result of
an experiment which I made in regard to a new application
of this metal to objects of manufacture.
~The apparent infusibility of platina by itself, formerly
considered as an insuperable obstacle, was sufficient to pre~
vent the employment of it except in combination with other
metals, as experience showed that it was capable of uniting
with the greater part of them by fusion. Of such mixtures,
that arising from a combination of brass and platina was.
found to be exceedingly proper for the specula of reflecting
telescopes, as this alloy was susceptible of a beautiful polish
not subject to be injured by the prejudicial influence of the
atmosphere and of moisture. At first, however, the em-
ployment of platina was not extended further until the ex-
periments made known by Morveau, Sage, and other che-
mists, and afterwards prosecuted on q larger scale by count
Von Sickingen, formed as it were an epoch in the history
of this metal, and showed in what manner platina might
be freed from its foreign particles, be welded, hammered,
and drawn out into-wire, so as to be applicable ta a variety
of purposes. ay 6 | oh ae

It was, however, not yet possible to employ it in cases
which required an actual fusion for the purpose of casting
it; because this metal, in its purified state, was always by
itself infusible in a common furnace, It was therefore
a discovery of great importance to find that platina may be
rendered fusible by arsenic ; and that when mixed with this

a a

in Porcelain Painting. 137

substance it may be cast in moulds, while the volatile metal
employed as a flux may be again driven off by heat, so that

the cast platina may then be: hammered hke any other me-
tal. By employing this method, first made known by my
worthy colleague M. Achard, nibsnels and articles of various
kinds are made of platina, and particularly at Paris.

Bergman, however, had shown that platina which could
be reduced to a state of fusion only by employing a large
burning mirror, might be fused also by means of oxygen
gas. Tp this manner M. Pelletier, by means of phosphoric
glass, made from bones, combined with charcoal powder,
brought large masses of platina to a state of complete
fusion.

How far platina might be employed in porcelain painting
has never yet, as far as I know, been examined: J there-
fore thought it of considerable importance to make some
experiments on this subject, which did not deceive my ex-

pectation ; but, on the contrary, convinced me that this

object, in the hands of an ingenious artist, may be brought
to perfection,

Gold and silver have hitherto been the only metals sus-
ceptible of heing employ ed in their metallic form in paint-
ing and ornamenting porcelain, glass, and enamel. Gold
answers this purpose so completely, that nothing further
can be wished for on this head; whereas silver “does not
answer so well, As it possesses cae density and is more,
porous than gold, it does not cover the ground so com pletely
when applied to porcelain in thin leaves. The second cause
pf the inferiority of silver when employed in painting on
porcelain arises from its nature, in consequence of which,
when exposed to sulphureous and other phiogistic vapours,
yt becomes tarnished, loses its metallic splendour, and at
length grows black. This inconvenience renders. silver
unfit for being employed in fine porcelain painting, and
confines the application of mmetallie substances in this man-
ner to gold alone.

Platina, in this respect, may be classed next to gold ;
and by its white colour may supply the place of silver with-
put possessing any of its faults. {t is not only capable, on
account of its density and weight, in which it exceeds gold,
of covering the ground completely, without leaving any
perceptible interstices ; as silver does; but it withstands like
gold all the variations of the atmosphere, as well as sulphu-
reous and other vapours.

The process which I employ in the application of platina
to painting on porcelain is sunple and easy: it is as fol-
ows:

138 Employment of Platina in Porcelain Painting.

lows :—I dissolve crude platina in aqua regia, and precipitate
it by a saturated solution of sal ammoniac in water. The
red crystalline precipitate thence produced is dried, and
being reduced to a very fine powder is slowly brought to 4
red heat in a glass retort. As the volatile neutral salt, com-
bined with the platina in this precipitate, becomes sub-
limated, the metallic part remains behind in the form of
a gray soft powder. This powder is then subjected to the
same process as gold; that is to say, it is mixed with &
small quantity of the same flux as that used for gold, and
being ground with oil of spike is applied with a brush to the
porcelain ; after which it is burnt-in under the muffle of an
enameller’s furnace, and then polished with a burnishing
tool. ;

The colour of platina burnt into porcelain in this man-
ner is a silver white, inclining a little toa steel gray. If the
platina be mixed in different proportions with gold, different
shades of colour may be obtained ; the gradations of which
may be numbered from the white colour of unmixed pla-
tina to the yellow colour of gold. Platina is capable of re-
ceiving a considerable addition of gold before the transition
from the white colour to yellow is perceptible. Thus, for
example, in a mixture of four parts of gold and one of
platina, no signs of the gold were to be observed, and the
white colour could scarcely be distinguished from that of
unmixed platina: it was only when eight parts of gold to
one of platina were employed that the gold colour assumed
the superiority.

I tried, in the like manner, different mixtures of platina
and silver; but the colour produced was dull, and did not
seem proper for painting on porcelain.

Besides this method of burning-in platina in substance
on porcelain, it may be employed also in its dissolved state 3
in which case it gives a different result both in its colour
and splendour. ‘The solution of it in aqua regia is evapo-
rated, and the thickened residuum is then applicd several
times in succession to the porcelain. The metallic matter
thus penetrates into the substance of the porcelain itself,
and forms a metallic mirror of the colour and splendour of
polished steel *.

* At the time this paper was read in the Royal Academy of Sciences,
the author exhibited several patterns of porcelain ornamented in this
Yranner, which had been made im the royal ebscrvatory.

XX, Ad-

“-

XX. Advantageous Method of preparing Red Oxide of
Quicksilver... By J. W. C. Fiscuer*.

as Mons has observed that, in the preparation of the
red oxide of quicksilver from nitrate of mercury, the whole
of the acid is far from being employed for the complete ox-
idation of the quicksilver, as during the heating of the ni-
trate of mercury a considerable quantity of the acid is
again obtamed. He therefore proposes the employment
of a larger quantity of quicksilver than the quantity of ni-
trous acid destined for the solution is facially able to dis-

solve, as this excess of quicksilver must also be oxidated b
2 q y

the heating of the salt brought to a state of dryness by the
escape of the acid. But as the nitrous acid of the shops
does noi always possess the same degree of concentration,
I gave a recipe in another work+ for finding the proper
proportion of quicksilver, which is as follows: If the hot
prepared dry nitrate of mercury be rubbed up with from
one-third to one-half part of metallic quicksilver, and ex-
posed in the usual manner to the fire, a proportion that
may be employed under all circumstances will be ob-
tained.

Mr. Schmidt, apothecary of Sonderburg, in consequence
of the before-:mentioned observation of C. Mons, made
several experiments on this subject without the wished-for
success, as he always obtained the excess of quicksilver in
a metallic form. ‘The results of my present experiments
were quite different, and fully answered my expectation.

I dissolved in a common heat four hundred parts of me-

‘tallic quicksilver in nitrous acid. To obtain a perfectly

neutralized solution, the acid was added only in drops till
all the quicksilver was dissolved. The solution was eva-
porated 10 dryness, in an evaporating dish, and the dry salt
was rubbed up with 350 parts of metallic quicksilver. The
powder assumed a dark gray colour: but when brought to
the consistence of a thick paste by a little water, in order
to complete the union of the metallic quicksilver, the
colour became grayish white, and, in general, only five
minutes were required to make the metallic quicksilver dis-
appear entirely. The humid mass was moderately dried on
a common stove, and being put into a retort was exposed
to asudden heat. In three minutes a disengagement of

*® Scherer’s Allgemeines Journal der Chemie, no. 42, 1802.
+ Handbuch der Pharmaceutischen Praxis, met einer Vorrede von D.S. F.
Hermlstadt, 1801.

oxygen

a ay
340 On several indigenous Plants which may

oxygen gas Was observed, and the whitish-gray
the whole mass was changed to ablackish red.
tion was then suspended ; > and, on cooling, the whe mass
exhibited throughout. that toa red colour obseryed’ i in
red precipitate, when reduced to a state of the greatest
fineness; and it was so much divided that it could be shaken
from the retort without breaking it. No traces of metallie
quicksilver remained, but a small quantity of acid fluid;
which induced me to repeat the experiment with a larger
quantity of mercury. I therefore took 400 parts of quick-
stlver, which were dissolved as before in nitric acid: when
the solution was evaporated to dryness, it was mixed with
400 parts more of metallic quicksilver, and the mixture
was treated as before. Except the difference jn the weight,
the results of this operation were not different from the
preceding.

This method not only saves one half of the nitric acid,
but the retort can be Several times used for the same pur-
pose. The tedious process of preparing precipitate is also

avoided, as it is soon obtained in the form of a very fine
pow der! The loss of time and of fire is also much less, as
several pounds of white mercurial paste can be converted
into red oxide in less than thirty minutes. I subjected to
experiment, however, only a few ounces, and the opera-
tion was always finished in from three to five minntes in
a sudden heat. On-this account the present method is

highly worthy the attention of chemists and apothecaries.
ning aes

XXII. A Memoir concerning several indigenous Plants, which
muy serve as a Substitute for Ouk Bark, and for certain
foreign Articles in the Tanning of Leather *, 7

Tue object of this memoir is to show how the destruction
of trees, and particularly of oak-trees, which are so valu-
able, may in great part be prevented. A great consumption
of them is caused by the tanneries. A discovery has been
made last summer, which will contribute to the preservation
of the trees, and to the continuation and even to the in-
crease of the tanneries, Eight new sorts of leather have -
been prepared and tanned without any bark at all, and with
materials of which we shall give a detailed account. By
using these articles, there is a saving, not only of bark,
but likewise of several foreign drugs, which are generally

* From the tenth volume of the Tiausactions of tbe Royal Academy of
Berlin. , :
used

serve asa Substitute for Oak Bark. ~ 14h

-Wsed in tanning. It is surprising that the experiments on
ech this discovery is founded have not been made sooner,
as they are exceedingly easy, and the various methods prac-
tised by other nations, and even by the most savage ones,
for making leather, pointed.out the way to them. ‘In fact,
be it owing to the want of bark, or to old practice, it is
usual in several countries to tan leather with leaves, roots,
fruits, and juices. We shall not enter now into all the
historical details of which the subject is susceptible ; but it

is proper, however, to give a sketch of them.

Some of the Calmuc Tartars, that rove about towards the
great wall of China, tan the skims of their horses with sour
mare’s miuk. In Persia, Egypt, and some countries bor-
dering on Africa, goats’ skins are tanned with the astringent
and leguminous fruit of the true acacia, which is gathered
before it is ripe. In several parts of the Turkish empire
the same skins are made mto Morocco leather by the means
of galls. The green nuts of the turpentine tree, and, ac-
cording to some, even the leaves, as likewise those of the
lentisk tree, serve for the same purpose in many parts of
the Levant. The smak, or bundles of the leaves and young
branches of sumach, is very well known, and is used in
all countries for the making of Cordovan leather. It is also
well known that in several provinces of Italy, Spain, and
}rance there are actually used several plants, ‘which may be

called plante coriarie, such as the arbutus, the celtis, the
tamarisk, the rhamnus, the rhus myrtifolia, &c. In Sweden
they use "the bark of one of the small species of mountain
sallow, as also a wild plant known by the name of ua
urst. The Silesians use m tanning a sort of myrtle called
rausch, But for tanning, nothing is used in Germany but
the bark of oak and birch tree, with some acorn shells ; and
as to the making of Cordovan and Morocco leather, they

use sumach and galls, as almost all other nations do.
When the eight new methods of preparing leather al-
ready alluded to shall be once introduced, all the other ar-
ticles will be no longer necessary ; and there will be found
in his majesty’s dominions the plants fit for tanning, among
which are some that will serve also for dyeing skins. We
have already about sixty species of such plants ; and if, after
having mide an exact choice, there should. remain but
twenty of them, our object will be attained, both as to the
preservation of wood, and the doing without foreign are

ticles.

Skins differ from each other according to the species of
animals, as likewise according to their age, food, and the
climate

142 On several indigenous Plants whieh may

climate they belong to; whence it follows, that there must
be various methods of tanning, all which can be reduced
to the three methods called in Germany weiss-gahr (white
preparation), semisch-gar (soft preparation), and toh-gahre
(tanning). Iomit parchment, shagreen, and what concerns
skinneries.

The first preparation is the same in these three methods.
When the skins are well cleansed, lime, or sand and salt
are made use of to take off the hatr, and then they are
washed several times, &c.

_ But the following part of the process is not the same in
these different methods. We shall omit at present the two
first methods, which require several ingredients taken from
the three kingdoms of nature, such as alum, comnion salt,
raw tartar, bran, meal, and fish oil; but it is necessary to
enter into some details with regard to the third, in which
vegetables alone are used, that serve to make a sort of lye,
by means of which the tanning is conipleted.

This third method can be subdivided again into four sorts,

. . * . . —)
according to the four principal sorts of leather that are pre-

pared with the help of different vegetables, viz. 1. Common
leather; 2. Cow’s leather; 3. Cordovan; 4. Morocco lea-
ther.

Every vegetable lye fit for making leather is either cold
or hot. ‘ F

The cold process is the simplest and easiest, buf, at the
game time, the slowest; it 1s used for the coarsest and
heaviest sort of skins, which are put in holes, or in wooden
vessels, with oak or birch bark.

The method of tanning with hot lyes is often very trouble-
some, but it is niore expeditious than the former one.
Some sorts of leather require three weeks; others eight,
twelve, or fifteen days. From twenty-four to thirty-six
hours are sufficient for Cordovan; Morocco leather takes
seven or eight hours, and sometimes from sixteen to twenty.
This method is as follows: The lye is poured imto wooden
vessels, together with hot water; the skins are put into it,
and stirred often. After eight days time the water is thrown
out, heated again, poured upon fresh lye, and the whole |
is poured upon the skins. This operation is continued and
repeated until the vegetable parts have penctrated the sub-
stance of the skins so as to change them into leather; which
is then dried, and given over to the curriers.

We may remark here, that cow leather cannot be made
as cheap with us as in Russia; and that the scented sort
ealled cuir de Roussi derives that property from two em-

L pyreumatic

- gerve as a Substitute for Oak Bark. 14¢

‘pyreumatic oils, which it is rubbed with in the preparing
of it.

» As to Cordovan and Morocco leather, they are made of
goats’ skins, and prepared, the one with sumach, the other
with galls, |

We have said enough concerning the general principles
of tanning, so as to throw a light upon what relates to the
plants that can be made use of in it. Pa

- There is abundance of these plants in our country, and
eight new methods of preparing leather with them have
been discovered. They have been’ treated of in a memoir
that was read before the academy on the 5th of last De-
cember. The author of this memoir, and the maker of
these new sorts of leather, is M. Klein, a native of Nauen.
He requested {I should show him all the plants that I
thought fit for tanning. I have mentioned the names of
these plants to the academy, and specified their properties.
They are all indigenous plants, very common and abundant,
and which have been heretofore considered as noxious weeds,
as the utility of them was not known; and accordingly,
their being used in tanning will not be in the least hurtful
to private economy. M. Klein has collected a considerable
quantity of these species of plants; and among the eight
sorts of leather that have been made with them there is very
fine Cordovan prepared without sumach, and two sorts of
calf-skin, tanned only with leaves of trees. :

These coriaceous plants grow in «almost all deep places
and marshy grounds; there are some of them found also
in sandy soil, on hills, and in woods. The hay which they
yield is the coarsest of all, and in very small quantity; the
cattle never touch it, except when they are starving with
hunger. Such plants spoil good meadows. A great quan~-
tity of them is to be had, particularly near lakes and large
ponds; and it is no exaggeration to say that there are sixty
species of them.

It is. very easy to discover the chemical principles in
virtue of which these plants are fit for tanning, if one has
# knowledge of those of sumach, galls, and different soris
of bark, With regard to this point, the plants may be di-
vided into two principal classes. The principles that are
chiefly to be considered are found generally in all of them;
they are of a fixed, but still active, terreo-gummy, or terreo~
resinoso-gummy nature. Besides these common principles,
some other very active ones exist in some of these plants,
in a greater or less quantity; and this is what eras
: ine

144 On several ihdigenous Plants which may

the difference that we establish between the plants that carr
be used in tanning.

‘Those of the first sort have no smell, or at most a very
weak one, but they havea very sharp ate astringent taste.
They contain only the active and fixed principles which we
have mentioned, or at most an inconsiderable mixture of
oleo- inflammable parts; which give a weak balsamic smell
to the water distilled from them ; without any sharp or styptic:
taste. The proportion of these parts varies in the terreo-
resinoso-gumnmy substance; but that which commonly
exists in the greatest part of the coriaceous plants is such,
that, for instance, in a pound of them the terreous parts
constitute one-third, or even one-half; and the gummy
principle about one- “fourth of one- third, and in some as
much as one-half, while the proportion of rosin is the
smallest of all, being only from twenty to fifty grains, or
at most a drsalid and about tw enty grains.

In the second sort of these plants we find; indeed, thie’
above-mentioned fixed active principles, but not. in the

same proportion, because they are nnxed with other prin-
ciples both volatile and fixed, so as to constitute the smallet
part of the whole compound. Besides the fixed parts there
exists mr these substances an unetuous balsamic oleoso-, or
vaporasa=spirituoso-ethereous principle. The volatile parts
become soon disengaged from the rest, by the heat of the
tanning lye, and.evaporate, so that it is not at all times
possible to discover any specific remains of them in the
leather.

If we examine next what the fixed terreo-gummy or
terreo-resinoso-gummy substance eonsists of, we shall ob-
tain a very clear knowledge of it, either from considering
the manner in which it ts s naturally produced, or by means
ef chemical experiments; This terreous matter 1s some=
times coarser, sometimes finer, sometiines in a greater and
sometimes in a smaller quantity ; and it contains an oily.
substance, or inflammable principle, attached to a light
acid, of the nature of vegetable acid, but not caustic, like
mineral acid. In analysing the fixed substance of coria#
ecous plants, we get by the alembic, out of a pound medi«.
eal weight, nearly the defer Aang parts, in a proportion:
more or less different: 1. About an ounce and two drachms
of a clear, Pas lS but not astringent phlegm ; 2.
About two ounces and five drachms of an acid yellowish li-
guor; 3. An ounce and somewhat more than six drachms
at an empy reumatic oil, The caput mortuum often con+

stitutes

serve as a Substitute for Oak Bark. 145

stitutes one half, or even more, and sometimes contains a

ortion of fixed alkaline salt. In dry fruits, juices, and
Thalbous roots, this proportion suffers some exceptions. It
is easy to conceive that the knowledge of these component
parts, of their respective quantities, and of their properties,
which are well known to chemists, may lead to that of
their effects, and of the manner in which they produce.
them. We shall be able then to distinguish a false tanning
plant from a real one, or to lay aside such as are too weak
for that purpose. There are some, for example, that are
much fitter for giving a fine dye to leather than for tanning
at.

Nor is it difficult, after what we have said concernin
the principles contained in the plants, to form.an idea of
their action upon skins, properly cleansed and macerated.
The skins being left steeping in a decoction of these plants,
or merely along with the coarse dust of them, undergo a
change in the tissue of their parts, whereby they heconie
leather. In this operation the soluble and active parts of
the vegetables are separated from the coarse mass, with the
help of air, evaporating moisture, water, work, and va-
rious degrees of heat. They remove imperceptibly from
each other, and extend in every direction in a very gentle
manner, which renders them fit for softly penetrating the
substance of the skins, and producing gradually an alter-

ation inthem. It is easy to comprehend the effects. which,

in such a case, a gentle acid is capable of producing, when
dissolved, mixed, and put in action with other particles
highly volatile, oleoso-ethereous, and of great mobility.
The skins are penetrated with these particles, and with
those which we have called terreo-resino-gummy, as if with
@ sort of balsam, and are thereby condensed into leather.
But as it is not our intention to enlarge upon the theory of
tanning, we shall confine ourselves to our object, which is
the indication of tanning plants, and shall mention another
propert of them, whereby they are plainly distinguishable

om all others. This property occurs in their dust, or in
a decoction of them, when mixed with copperas (vitriol
de mars).

Take then these plants, and reduce them into dust, which
you will throw into a solution of copperas; or put some
copperas into an infusion or decoction of the plants which
has been previously filtrated. The colour produced by this
mixture is sometimes reddish or of a dark red, and some-
times blue or black, The cause of this phenomenon is
known to chemists, who know also how to make these

Vou. XVII. No. 66. K decoctions

146 On several indigenous Plants which may

‘decoctions or infusions transparent, and to make the colours
- disappear, by pouring into them, drop by drop, a sufficient
quantity of oil of vitriol.

The properties of these plants being thus sufficiently as-
certained, and there being the greatest plenty of them in
the country, it remains now for the connoisseurs to extend

: the use of them, and to apply them further to the advantage
‘of our national manufactures.

A List of the Plants that have been used in the Experiments
on Tanning. F 7

The number of plants fit for tanning is much greater than
. that of those in the following list; and it has been observed
‘ that, if they be gathered at proper seasons, they can be used
for the preparing of all sorts of skins, both coarse and fine.
The best of them are such as have the greatest quantity of
a coarse, astringent, and acid substance. They are also
the fitter for penetrating the skins, in proportion as they
contain a greater portion of aromatic and spirituous parts,
. and are possessed of an essential ethereous oil. On the
_ contrary, the inferior species of them are those whose sub-
stance is principally composed of fat or mucilaginous.parts,
. which do not make so strong an impression on the skins,
_ and can scarce serve for tanning the most tender ones.
Salicaria vulgaris purpurea,» foliis oblongis. Tourn.
Instit. 253. Lysimachia spicata purpurea, forté Plinio.
C. B. pin. 246. Purple-flowered loosestrife.
Ulmaria; Clus. Hist. 198. I. B. 11. 488. Regina prati.
Dodon. Pempt. 57. Queen of the meadows.
Comarum ; Linn. Gen. pl. ed. 5. 563. Quinquefolium
, palustre rubrum. C. B. pin. 326. Red marsh cinquefoil,
Filix ramosa major, pinnulis obtusis, non dentatis. ‘Oh
B. pin, 357. Filix foemina offic. et Dodon. Pempt. 462.
. Common brackens, or female fern.
Filix non ramosa, dentata. C. B. pine 358. - Filix-mas
offic. et Dodon. Pempt. 462. _Common male fern. -
Filix palustris maxima. C.B. Prodr. 150. Water-fern.
mas aculeata, major et minor. C. B. Prodr. 151.
Persicaria salicis folio, potamogeton angustifolium dicta.
Raj. Hist. 184... Arsmart. :
Persicaria acida Jungermanni. Water knot-grass.
Bistorta, major, radice minus vel magis intorta, C. B.
pin. 192. Snake-weed. Meet Pies
Tormentilla sylvestris. C. B. pin. 326. Wild tormentil.
Pimpinella sanguisorla major. C..B. pin. 160. Large
. wild pimpernel.

Caryophyllata

serve.as a Sulstitute for Oak-Bark, ° * 147

. Caryophyllata vulgaris. C, B. pin, 321. Common ayens,
or herb bennet.

Caryophyllata aquatica, nutante flore, C.B, pin,.321.
Water avens,

_ Anserina offic, argentea. Dod, Pempt. 600. et Poten=
tilla. I, B. Il. 398. Goose-grass. ‘

Quinguefolium majus repens, C, B, pin, 325. Large
cinquefoil,

Juinquefolium minus repens luteum, C, B. pin. 325.
Spring cinquefoil.

Quinguetolium folio argenteo, C, B; pin, 325. Satin
cinquefoil,

Horminum pratense, foliis serratis,C, B, pin, 238, Clary,

Agrimonia offic. Agrimony.

Equisetum arvense, longioribus setis, C, B, pin. 16,
Horse-tail.

Equisetum palustre, longioribus setis, C. B. pin, 15.
Marsh horse-tail.

Alchemilla vulgaris. C, B, pin, 319, Common. lady's
mantle.

Muscus pulmonariyus, sive Pulmonaria offic. Lob.: Ic,
p- 248. Pulmonaria arborea, Muscus quernus. Oak moss,

Lysimachia lutea major, que Dioscoridis, C, B. pin.
245. Yellow wood-loosestrife.

Vaccinium; Rivini, Vitis idea, foliis oblongis crenatis,
Sructu nigricante. C, B, pin. 470, Black-worts—in Irish
Fraochan.

Vaccinium foliis lbuxi, sempervirens, baccis . rubris.
Rup. flor. Gen. p. 52.. Red bilberry.

Rubus vulgaris, s, fructu nigra. C. B. pin. 479, Com-
mon bramble.

‘ Rubus repens, fructu cesio, C, B, pin. 479, Dew-

erry.
esis vulgaris. C, B. pin. 326, Strawberry.
Filipendula; I. B, 11. 189. Saxifraga rubra off, Red
Saxifrage. i

Peryinca; Tournefort. Vinca pervinca offic, Clematis
daphnoides major, jflore ceruleo, I, B, Il, 132. Peri-
winckle. :

Sparganium ramosum et non ramosum. C, B, pin. 115.
Burn-reed, ‘4
_, Filago; seu herba impia, Dodon. Pempt. 66. Common
cudweed. 2
_ Gnaphalium montanum flore rotundiore et longiore,

Tourn, Inst. 453. Mountain cudweed,

on . Ke Geranium

148 Plants which may serve as a Substitute for Oak Bark.

Geranium sanguineum maximo fiore. C. B. pin. 319.
Bloody crane’s bill.
batrachoides maximum, minus tlaciniatum,
folio aconiti. 1. B. 111. 477. Meadow crane’s-bill.

Plantezo (aiifolia incana. C. B. pin. 189. Broad-leaved
plantain. — er

———— angustifolia major et minor. C. B. pin. 189. Nar-
row-leaved plantain, both great and small.

latifolia sinuata. C. B. pin. 189. <All sorts of

plantain.

Hypericum offic. et Matthiol. vulgare. C.B. pin. 279.
Commion St. John’s wort.

Itis proper to observe in this place, that only the herbs in
flower, or even the flowers alone, of the preceding plants
are to be used.. Some of them are more weak than others,
and accordingly must be used in a different way. But as
to the following ones, their leaves and branches, as likewise
the unripe fruits of them, the seeds, and even the roots of
“some of ‘them, are all equally fit for tanning.

Frondes vitis vinifere. The vine. ;

Prunus sylvestris. Wild plum+tree; its berk and un-
ripe fruit. i

Salix vulgaris alba arborescens. Common white wil-
low ; its leaves and twigs.

— caprea rotundifolia. Common willow ; its leaves,
bark, twigs. . pte

Rosa; sylvestris, varioruam colorum. Wild rose-bush;
its leaves. en

Fagus. Beech, Bark and leaves. .

Carpmus. Fforse=becch. Bark and leaves.

Quercus. Alb sorts of oak. Leaves.

Betula. Birch-tree. ~ Bark and leaves.

Alnus. Alder. Leaves. .

Mespilus; species sylvestris vulgaris. Wild medilar.
Leaves, twigs, unripe fruit. a ! preg:

Ledum rosmarint folio. Wald rosemary.

Cornus ‘sylvestris mas. Wild cornel tree. Leaves,
twigs, ‘stones. .

_ Acetosa pratensis. Sorrel. Root. Seed.

‘Lapathum »naximum aquaticum. Large water-dock.
Root, leaves, seed. y
--Lapathum folio acuto plano. C. B. pin. 115. Sharp-
pointed dock. Root, leaves, seed. aps.

Iris palustris lutea. Acorus adulterinus. C, B. pin. 34
Water-flag. Root. 3
Nymphea

Process for Dyeing Nankeen Colour. 149

Nymphzea lutea major. C. B. pin..193. Yellow water-
lily. Root.

alta major. C.B. pin. 193. White ditto.

Root.

XXIL. Process for Dyeing Nankeen Colour. By Mr. Rucnarp
BREWER.*

Mix as much: sheep’s dung in clear water as will. make if
appear of the colour of grass, and dissolye in clear water
one pound of best white soap for every ten pounds of
cotton-yarn, or in that. proportion for a greater or: lesser
quantity.

Observe :—The tubs, boards, and poles, that are used in
the following operations must be made of deal ; the boiling-
pan of either iron or copper.

First Operation.
_ Pour the soap liquor prepared as above into the boiling-
pan ; strain the dung liquor through a sieve ; add as much
thereof to the soap liquor in the pan as will be sufficient to
boil the yarn, intended to be dyed, for five hours. When
the liquors are well mixed in the pan, enter the yarn, light
the fire under the pan, and bring the liquor to boil in about,
two hours, observing to increase the heat regularly during
. that period. Continue it boiling for three hours, then take
the yarn out of the pan, wash it, wring it, and hang it in
a shed on poles to dry.. When dry, take it into a stove or
other room where there is a fire; let it hang there until it
be thoroughly dry, |

N. B. The cotton yarn, when in the shed, should not
‘be exposed either to the rain or sun: if itis, it will be un-
equally coloured when dyed.

Second Operation.

Tn this operation use only one half of the soap that was
used in the last, and as much dung liquor (strained as_be-
fore directed) as will be sufficient to cover the cotton yarn,
when in the pan, about two inches, When these liquors
are well mixed in the pan, enter the yarn, light the fire,
and bring the liquor to boil in about one hour; then take
the yarn out, wring it-without washing, and hang it to dry
as in the former operation,

* From the Transactions of the Dublin Socicty, vol. i. part 1.

Third

150 Process for Dyeing Nankeen Colour. .

Third Operation.
This operation the same as the second in every respect.

Fourth Operation.

For every ten pounds of yarn make a clear lye from half
a pound of pot or pearl ashes. Pour the lye into the boil-
ing-pan, and add as much cleaf water as will be sufficient.
to boil the yarn for two hours; then enter the yarn, light
the fire, and bring it to boil in about an hour. Continue
it boiling about am hour, then take the yarn out, wash it
very well in clear water, wring it, and hang it to dry as in
former operations.

N.B. This operation is to cleanse the yarn from any
oleaginous matter that may remain in it after boiling in
the soap and dung liquors.

Fifth Operation.

To every gallon of iron liquor* add half a pound of rud-
dle or red chalk (the last the best) well pulverized. ;

Mix them well together, and let the liquor stand four
hours, in order that the heavy particles may subside ; then
pour the clear liquor into the boilmg-pan, and bring it. to
such a degree of heat as a person can well bear his hand in
it; divide the yarn into small parcels, about five hanks in
each; soak each parcel or handful very well in the above
liquor, wring it, and lay it down on a clean deal board.
When all the yarn is handed through the liquor, the last
handful must be taken up and soaked in the liquor a second
time, and every other handful in succession tll the whole
is gone through; then lay the yarn down in a tub, wherein
there must be put a sufficient quantity of lye made from pot
or pearl ashes, as will cover it about six inches, Let it hie
in this state about two hours, then hand it over in the lye,
wring it, and lay it down on a clear board. If it does not
appear sufficiently deep in colour, this operation must be
repeated till it has acquired a sufficient degree of darkness
of colour: this done, it must be hung to dry as in former
operations. pron i

N, B, Any degree of red or yellow hue may be given
to the yarn by increasing or diminishing the quantity of
fuddle or red chalk.

Sixth Operation.
For every ten pounds of yarn make a lye from half a

* Tron liquor is what the linen printers use.
q P

pound

On the Benzoic Acid in the Urine of Horses.. 151

pound of pot or pearl ashes; pour the clear lye into the
oiling-pan ;_ add a sufficient quantity of water thereto that
will cover the yarn about four inches; light the fire, and
enter the yarn, when the liquor is a little warm ; observe
to keep it constantly under the Jiquor for two hours 5 ‘in-
erease the heat regularly till it come to a scald ; then take
the yarn out, wash it, and hang it to dry as in former ope-
rations.
. Seventh Operation.

' “Make a sour liquor of oil of vitriol and water; the de-
eree of acidity may bea little less than the juice of lemons 5
ay the yarn in it for about an hour, then take it out, wash
it very’ well and wring it; give it a second washing and
wringing, and lay it on a board.

* N.B.. This operation is to dissolve the metallic particles,
and remove the ferruginous matter that remains on the sur-
face of the thread after the fifth opertion. : )

Eighth Operation.

For every ten pounds‘of yarn dissolve one pound of best
white soap in clear water, and add as much water to this
hiquor in your boiling-pan as willbe sufficient to boil the
¥arn for two hours. When these liquors are well mixed
hight the fire, enter the yarn, and bring the liquor to boil
i about an hour. Continue it boiling slowly an hour;
take it out, wash it in clear water very well, and hang it to
dry as in former operations: when dry it is ready for the
weaver.

_N.B. It appears to me, from experiments that I have
made, that less than four operations in the preparation of
the yarn will not be sufficient to cleanse the pores of the
fibres of the cotton, and render the colour/permanent. — *

>

XXIII, On the Benzoic Acid in the Urine of Horses. By
ous M. Ferpinanp Giese, of Berlin*. Wee) C4

Accorptne to the researches of Fourcroy and Vauquelin
on the urine of different graminivorous animals, the benzoic
acid at all times farms a component part of it, Partly with
a view to place this beyond a doubt, and partly that I might
accurately determine the proportion which this substance
bears to the other component parts, I made the following

* From Scherer’s Allgemeines Journal der Chemie, 0. 43. {
% K4 experié

152 = On the Benxoic Acid in the Urine of Horses.

experiments ; but these conducted me to phenomena which
induced me to proceed further than I had-at first purposed,
Experiment 1. fits
Ta two pounds of fresh horse’s urine I added muri«
atic acid the specific gravity of which was as 115 to

100. A weak effervescence took place, and there were.

formed thick white vapours, which soon fell to the bottom
like flakes. I now continued to add muriatic acid till no-
thing more was separated, and till there remained a small
excess, three ounces of acid having been employed. The
whole was then placed on a filter; and the precipitate, being
washed with pure water to free it from the urine still ad-
hering to it, was then dried, It amounted in weight to twe
drams and forty-eight grains. On being subjected toa
proper test, it evidently exhibited all the properties by which
the benzoic acid is characterized ; namely, a scarcely sour-
ish taste, crystallization, complete volatility, the disengage~
ment of an acrid vapour, which occasioned pain in the breast,
and ready solution in spirit of wine. j
Having fully conyinced myself by this experiment of the
abundant existence of benzoic acid in urine, I continued
my. researches on the urme of more horses, partly with 4
view of observing the difference of the proportions in it,
and partly to ascertain whether something . determinate
might not he established on this. subject.

Experiment Hl.

Four pounds of urine were subjected to the same treat-
ment as before, The phenomena were here different from
those of the first experiment; for, on adding muriatic acid,
no precipitate was produced. When the fluid was evapo-
rated to a fourth, and after the fluid had stood at rest for
some time, I observed a small and resin-like precipitate,
which, after being treated with spirit of wine, gave benzoi¢
acid, hut in so small a quantity that it bore no proportion
to that of the first experiment, for it amounted only to five
grains, y

Experiment V1.

Eight pounds of horse’s urine being evaporated to the
eonsistence of syrup, muriatic acid was then added; but
no precipitation ensued. The fluid was then brought to
complete dryness ; and spirit of wine being poured over it,
when it had stood some time the undissolved residuum was
separated by the filter, and the liquor evaporated. I ob-
tained a very small quantity of crystallized benzoic acid,

3 which,

On the Benxoic Acid in the Urine of Horses. 15%

which, as none appeared by pouring muriatic acid into the
urine evaporated to the consistence of syrup, must have ex-
jsted in the urine in a free state. The weight of it amounted
to fifteen grains. :
; Experiment IV.

Five pounds of urine were evaporated to dryness, and a
fourth part of alcohol being added, the whole was exposed
to heat. The alcohol, which after some time had acquired
a dark colour, was again filtered and evaporated. No traces
“ef benzoic acid, however, were perceptible,

: Experiment V.
~ Of four pounds of urine a small part was subjected to
previous proof by muriati¢ acid: a nebulous precipitate im-
mediately took place, but on the addition of more muriatie
acid it again disappeared. The remaining urine not decom-
sed with muriatic acid I evaporated to the consistence of
syrup, by which means a great quantity of pure calcareous
earth was separated; to the discovery of which I was con-
ducted by dissolving the residuum in muriatic acid, which
was very easily done, and without effervescence. Havin
dropped sulphuric acid into this solution, sulphate of lime
was immediately formed. ‘The urine separated from the
calcareous earth was decomposed by. sulphuric acid: there
was formed a perceptible precipitate, which being digested
with alcohol had lost none of its weight, and which way
merely sulphate of lime. The precipitate then, first pro=
duced in the unevaporated urine by muriatic acid, did not
y_any means arise from benzoic acid. :

It appears from these experiments, that in consequence
of the great difference observed in them. it is not possible
to determine the proportions of the component parts of the-
urine.

In the many experiments which I made with the urine
of different horses, I always found deviations in those which
¢contanied benzoic acid. In general, I found none of this
acid ; in some cases, but very seldom, I found a considera
ble quantity of it; calcareous earth I found only once.

Whence then arises this great difference? The answer
to this question will, perhaps, make us better acquainted
with the cause of these differences. To accomplish this
end, it was, in the first place, necessary to examine into the
origin of this acid, whether it was formed from the veges
tables on which the horses fed, and conyeyed into the urine
er whether it was created in the animal body by: the pent)
: action

454 On the Benxoic Acid in the Urine of Horses:

action of its original elements. _ I therefore first undertook
to examine the usual food of these animals, hay and oats.
Hay contains a large quantity of a grass with a very agreea-
ble smell, the anthowanthum odoratum Linn. Fourcroy and,
Vauquelin had already suspected that this plant contained
benzoic acid: this and other considerations confirmed me
in the same opinion, and gave me reason to hope that |
should find in it the source of the benzoic acid.

711 OF Experiment I:

A quantity of this grass was put‘into a very dry retort™

connected with a balneaum marie, and, being placed in a
sand-bath, was exposed to such a degree of heat that the
benzoic acid contained in it could be subhimated ; ‘but after
the fire had been maintained a considerable time, no traces

of it were observed, ) . k

_ Experiment I.

One part of this grass was boiled with twelve parts of
lime water. The decoction had a very agreeable smell: it
was then brought to the consistence of syrup ; and-muriatic
acid being added, a precipitate was produced, which how~
ever on being tried exhibited none of the properties of ben=
zoic acid. Leni
Experiment Vf. ’
» An extract prepared from a quantity of this grass had a
very strong smell, very much like that of the ¢rifolium me-
Filotumt. This extract, bemg digested some time in spirit
of wine, had a very agreeable smell. It was then exposed
to a slow evaporation, after which it exhibited no pereepti+
ble traces of benzoic acid.

It results from these experiments, made in different ways,
that the benzoic acid does not originate from the hay.

Jt now remained for me to examine oats: I therefore sub4
fected it to the same process, but could discover no signs
of benzoic acid.

Being confident that I had pursued the right method in
these experiments, I thought myself authorized to conclude
with certainty that I must look for the origin of the benzoi¢
acid in-the antmal body itself. The following experiments
will serve as a confirmation of this idea: ;

* ¥ examined the urine of a horse which had been fed on
ihe same food as that given to those the urine of whiclt
produced a large quantity of benzoic acid. This urine,
however, produced very little. Had the benzoic acid been
indcbtec for its. origin to the food, the urine of horses fed
* , Om

On the Benxoic Acid in the Urine of Horses. 138

on the same fodder must have produced a like quantity of |
benzoic acid; which, after repeated experiments, was not

found to be the case. A question now arises, In what state

of the animal is this acid formed in the body? in the sound’
_ or diseased state? I flatter myself that I am able to answer

this question, as I had an opportunity of ascertaining, with

great correctness, the state of the horses the urine ot which

T examined. The result was, that a horse whose urine gave

a great deal of benzoic acid had been long diseased, and

that the horse whose urine gave very little or no benzoic:
acid was perfectly sound. But what is the disease during

which benzoic acid is produced? This question is the most

important and most difficult. The determination of it is of —
great importance to the physiologist, as it calls his attention
towards the cause of the formation of this acid; and is
worthy the notice of the chemist also, as it holds forth an in-
diicément for him to examine under what. circumstances he
can derive utility from this product.

For this purpose a long series of experiments would be
necessary ; but these experiments can be made only by those
who have the care of diseased horses, that is to say, ina
veterinary college. Hitherto I have had no opportunity of
undertaking this labour; I shall therefore content myself
with collecting into one point of view the facts which seem
to result from these experiments.

I, The urine of horses is so very different, that nothing
certain can be determined in regard to the quantity of ben-
zoic acid which it contains. ; sd

IL. The following five cases, however, occur if this re-
Spect in the preceding experiments :—1st, There are some
kinds of urine in which at first a large quantity of benzoic
acid is found neutralized with soda: 2d, In which a very
small quantity of benzoate of soda exists: 3d, In ~which
the same quantity is found in the free state: 4th, In which
none is to be found: and, 5th, In which only a large quan-
tity of pure calcareous earth is observed. ms

III. The difference of urine in regard to the benzoic acid
it contains, does not arise from the food of the horses, but
from the various states in which these animals may be by
derangements in their functions.

IV. The state of the animal in which a quantity of ben-
zoic acid is produced, is worthy of further examimation. ~

Remark ly M. Scherer.

It is always very difficult in researches of this kind to
obtain certain results, I think there is great reason to be-
‘ lieve

¥356 On some Properties of the Phosphoric Acid

heve that benzoic acid is to be found in the urine of every-
sound horse; but the principal point is the time when it is
voided, It is well known that in the wrina cruda of man
very little uré is found; nay, it often seems to be entirely
wanting. On the other hand, it is always found in the
urina cocka of persons who are in a sound condition. May,
not the ease be the same with animals? Is it not therefore
more than probable that the concocted urine of sound horses,
always contains benzoic acid, when no. trace of it is to be
found in the crude urine of the same animals? This dif-
ference is of so much, importance that it ought not to be
entirely overlooked. i

XXIV. On some Properties of the Phosphoric Acid not yet
~ sufficiently known. By M.J.F.Gurrsen, Apothecary of
Kiel," oF

I. Susceptibility of crystallization.

Tue property which the phosphoric acid possesses of being
transformed into a vitreous mass by exposure to heat, was
one of its characteristic signs first known: this was not the
case, however, with its susceptibility of crystallization. It
is not improbable that the method long employed of ob-
taining it from urine and bones, and the continued fusion
of it to free it from the sulphurous acid, may have pre-
vented chemists from knowing it in chat state of concen-
tration in which it shoots into crystals.

De Lassonne and Cornette +, however, speak of a phos-
phoric, acid which was in the ratio of 19-8 to water, and
which being mixed in the proportion of two parts to one
part of water, formed after cooling a gelatinous kind of
wass. This phenomenon, however, while the phosphoric
acid was so much diluted, seems to have arisen rather from
a mixture of earthy matter than from the property of the
acid to crystallize.

Gattling } is undoubtedly the first chemist who observed
this property of the phosphore acid, which he did acci-
dentally, on having suffered phospherns to stand for three
months in a cellar in a glass filled with carbonic acid: at
the end of this period he found the sides of the glass co-

* From Scherer’s Beemeines Sournal der Chemje, na. 44,
+ Mem. del’Acad, de Paris,1780; and Crell’s Chem. Annals, 1756,
vol. in.
¢ Gowling’s Taschenbuch fur das jahr, 1797.
vered

no? yet sufficiently known. 137

ered with sharp-pointed crystals, which on closer éxamina+
tion were found to consist of pure phosphoric acid.

No further observations, however, as far as I know, were
made on this property of the phosphorie acid; nor was the
crystallization of it in larger quantities ever remarked.
~ Having been frequently employed in preparing phos
phoric acid from phosphorus, I had an opportunity to ob=
serve that it possessed the following properties :

ist. Four ouncés of phosphoric aeid, perfectly free frora
nitric, muriatic, and sulphurie acid, as appeared on trying
it with a solution of silver, caustic :me, and a solution of
barytes, and the specific gravity of which, at the tempera*
ture of 12° Reaumur, was to that of distilled water as 2-1,
shot up, by rest, into feather-like crystals in the course of
a few weeks, during which time the temperature of the at-
mosphere varied between +.2° and — 1°..

This acid, having remained seyeral days in a temperature
which varied from — 2° to — 8°, it curdled into an opake,
thick, tallow-like mass, in which no regular crystallization
was any more observed.

To convince myself of the absence of siliceous earth,
which might have been taken up by the acid in consequence
of its continual contact with the glass, and which might
have produced this curdling, I took some of the curdled
acid, by means of a glass rod, from the glass in which it-
‘was contained, and placed it on my hand, where by the
heat it was immediately transformed into a fluid perfectly
transparent.

On diluting it with two parts of distilled water, and sa~
‘urating it with carbonate of potash and of soda, no earthy
precipitate was formed: I observed also, that the glass in
which the acid had been kept showed no signs’ of havini
been in the least attacked. These were sufficient proofs that
the acid was not rendered impure by siliceous earth.

“ad. An ounce of crystallized acid, which by heat had
been brought again to a fluid state, was exposed m-a small
glass tube to the temperature of — 36° Reaumur, produced
by amixture of equal parts of snow and muriate of lime. At
the end of 15 minutes the mixture was taken from this ex=
‘posure to cold, as fluid as. it was before the experiment : the
same acid in the course of some days, in the temperature
of — 2°, returned to the same tallow-like consistence. -

It appeared to me to result from this experiment, that
the crystallization of the phosphoric acid: is not produced
‘by alow temperature alone, but chiefly by rest.

_ Thie conjecture I found fully confirmed by several other -
quantities

158 On some Properties of the Phosphoric Acid

quantities of phosphoric acid of from 8 to 12 ounces, which
I was-obliged to prepare during the course of the last suri-
mer, and which crystallized, though more slowly than in
winter, in a temperature of from 10° to 16° of Reaumur.

The whole mass of acid generally curdles into tallow-like
Jumps, which exhibit signs of crystallization only at the
surface. I have, however, been able several times to obtain
the quantity of six ounces in needle-like crystals, which re-
sembled the acid of sugar, and which remained unaltered
during the hottest days of summer,

3d, Acid of a Jess specific gravity I was not able to make
erystallize; but by the addition of more water it curdled in
the course of some time into a thick irregular mass.
_ It thence appears, that to make phosphoric acid erystal-
hize, it requires besides rest a degree of concentration, which,
according to its specific grayity, must be as 2 te 1 of distilled
water.

TI, It does not appear to have been yet proved, whether phos~
phoric acid produces or not a precipitate in a solution of
nitrate of silver. .
It is asserted in some Elements of Chemistry * that ni-

trate of silver is decomposed, and suffers the phosphate of

silver produced to be separated from it as a white precipitate.

Others ¢ refer to the experiménts of Margrafft, who, by
T™means of an acid prepared from salt of urine, precipitated
silver dissolyed in nitrous acid in the form of white soft
Jumps. Morveau § asserts also, that silver is precipitated
from its solution in nitrous acid by phosphoric acid.

Lavoisier |}, as far as I know, is the anly person who has
dgnied this precipitation; and Moryeau wonders how La-
voisier could assert that no precipitate is formed. The opi-
nion of so celebrated an observer, however, was of so much
weight, that | was unwilling to entertain any douht on this
subject without further proof.

I therefore dissolved four gras of the crystals of nitrate of
silver in a sufficient quantity of distilled water, and twa
gros of concentrated phosphoric acid prepared by nitric acid
and phosphorus were added.

At first, a quantity of small crystals which had a perfect

* Hermstadt’s Experimental Chemic, part ili, p. 11g.

4 Gren’s Handbuch der Chemie, second edit. part il. p. 168.

t Margraff’s Chemical Works, parti. p. 107. 1G

§ On the Acid Salts decomposed by Bourzuct, vol. ii, p.284,

} Lavo'ster’s Chemical Works, translated into German by Weigel,
Yoh. te p. gi’. :

resemblance.

not yet sifficiently known. . ha9

sesemblance to nitrate of silver fell to the bottom, and
which, by a proper mixture of concentrated acid, and the
addition of a little water, was again dissolved.

This precipitation of crystals before the phosphoric acid
was diluted may be easily explained by this circumstance,
-that the concentrated acid, which had the appearance of
-thick syrup, greedily attracted some of the solyent from the
nitrate of silver, by which means a part of the nitrate of

-silver was necessarily obliged to crystallize ; as is the case

in all saline solutions when deprived of their aqueous prin-

ciples by the addition of other bodies,
As no precipitate was produced by a proper mixture of

phosphoric acid with a sclution of nitrate of silver, I am of

opinion that the assertion of Lavoisier may be confirmed ;

namely, that nothing was separated from a mixture of phos-
phoric acid and nitrate of silver.
To obtain more certainty on.this subject, I prepared a

small quantity of phosphate of silver by precipitating a so-
‘lution of silver with phosphate of soda, one part of which

I mixed with nitric acid, and the other with diluted phos-

“phoric acid. In both cases the phosphate of. silver was

completely: dissolved.
If a decomposition therefore should take place in a mix-

“ture of phosphoric acid with a solution of nitrate of silver,
enough of free acid will still remain to preyent the precipi-
‘tation of the phosphate of silver.

__ It however appears from the following experiments that
such a decomposition is not probable. ~

_ Two gros of nitrate of silver dissolved in a sufficient
quantity of distilied water, were mixed with one gros of
concentrated phosphoric acid, and the clear solution was

_ subjected to slow distillation over a lamp.

. %

‘he matter which passed over had not the least taste of

“acid, even when the degree of the heat was increased by

enlarging the flame of the lamp, As soon as the formation
of small crystals was observed in the retort, I interrupted

the distillation, and left the mixture at rest to cool.

At the end of seyeral hours a great many erystals of ni-
trate of silyer had shot up, which when dried gave nearly
the same weight again, After repeated solution and slow

_ erystallization, all the properties of nitrate of silver were

observed.

The fluid which remained over the crystals in the retort
had an exceedingly sour taste, which was perceptibly that
ef the phosphoric acid: it left on the tongue, however, a

metallic
1

260 On some Properties of the Phosphoric Acid

metallic savour, and tinged the skin black ; but the latter |
property. does not belong to phosphate of silver.

By rest a considerable quantity of nitrate of silver still
etystallized, but the metallic savour was not yet entirely
lost.

More crystals continued to appear by spontaneous €va-
poration, in consequence of which the metallic savour be-
eame still less perceptible: but as the crystals possessed ali
the properties of nitrate of silver, I considered all further
examination of the supernatant acid as superfluous, as it
could be nothing else than phosphoric acid.

Wil. 4 doubt similar to that in regard to the question,
Whether solution of silver is decomposed ? arises in regard
to that, Whether a solution of muriate of barytes gives:a
precipitate by mixture with phosphoric acid ?

Morveau poured phosphoric acid into a solution of mu-
riate of barytes, and obtained a precipitate of phosphate of
barytes *.

Gren F found it confirmed, by his own experiments, that
the phosphoric acid decomposes muriate of barytes by sim-
ple affinity. 73
_ As phosphate of barytes is so easily dissolved by free acid,
I was of opinion that this assertion of that chemist, how-
ever respectable, was not to be admitted without further
examination. :

To ascertain the truth of my conjectures, I dissolved in
distilled water two gros of perfectly pure muriate of barytes ;
and having mixed it with one gros of concentrated phos-
phoric acid which had been before somewhat diluted in di-
stilled water, no trace of precipitate appeared.

A repetition of this experiment several times with the
same and larger quantities of these substances, confirmed
the observation, that no precipitate is formed by a mixture
of pure phosphoric acid with a solution of pure muriate of
barytes. ‘

As in every case when a very small quantity of phospho-
ric acid was dropped, a very perceptible taste of this acid
was observed, this phenomenon seemed to show that no
decomposition of the muriate of barytes had taken place.

To ascertain this, however, ‘beyond a doubt, I mixed the
solution of two gros of muriate of barytes with one gros of

* Morveau ut supra; and Macquer’s Chem. Dict. part iv.
4 Handbuch der Chemie, vol. i. p. 00: 2
phosphoric

not yet sufficiently known. 161

phosphoric acid, diluted the mixture with distilled water,
and exposed it to distillation over a lamp.

The fluid which passed over had not the smallest taste of
acid, and produced no action on lacmus paper. As soon
as crystals began to be formed, the distillation was ended.
There were separated 45 grains of a salt which possessed
all the properties of muriate of barytes.

By repeated distillation of the remaining acid fluid, which
had a very perceptible taste of phosphoric acid, I again ob~
tained by degrees the two gros of muriate of barytes, and as
little altered as the phosphoric acid which I had employed
for this experiment.

My conjecture was still further confirmed by the follow-
ing experiments ;

ist. The solution of an ounce of muriate of barytes was
mixed with half an ounce of concentrated phosphoric acid,
by sufficiently diluting it with distilled water.

ad. I evaporated the mixture in a glass capsule till it ap-
peared dry on cooling. At the end of the operation a great
quantity of pungent muriatic vapours were disengaged.

3d. The saline mass, which had a very acid taste, was
avashed with alcohol till the fluid no longer turned lacmus

; er red, and until the salt was entirely freed from the ad-
iering acid.

4th, The washed salt, when dissolved in distilled water,
faye a precipitate, which when washed and dried weighed
20 grains.

5th. To ascertain the nature of this precipitate, which
jad no saline taste, and which made a noise under the teeth
like an earth, I boiled it with 30 grains of the carbonate of
soda, and then edulcorated the liquor.

6th. It dissolved completely in muriatic acid with very
futle effervescence, and when mixed with sulphuric acid
wave an abundant precipitate.

7th. The spirit of wine (3) which had taken up the salt
adhering to the acid was distilled in a retort till the resi-
duum had acquired the consistence of a ayrup-

8th. The result of the distillation, when a solution of
silver wes dropped into it, showed traces of a little free
acid.
gth. The acid in the retort, which had a very perceptible
taste of phosphoric acid, was no longer impure by muriatic
acid. Jt rendered Jime water exceedingly turbid, and in
weight amounted to three gros and thirty grains.
oth. The saline solution (4) gave, after crystallization,
Vou. NVIL. Wo. 66. L. seven

162 Description of a New Safety-Piston.

seven gros and three grains of salt, which exhibited the samme
phenomena as muriate of barytes.

It appears to result from these experiments, that in eva-
porating a mixture of a solution of muriate of barytes and
phosphotie acid, towards the end of the process, when the
saline ifiass already,formed is capable of bearing a greater
degree of heat than that of boiling water, some muriate of
barytes. is decomposed, which can combine with a part of
the free phosphoric acid. ra

But that no proper decomposition of the muriate of
barytes takes place by the action of the phosphoric acid,
seems to be proved by the large quantity of undecomposed
salt and pure phosphoric acid which was again obtained.

I shall abstain from any further inquiry why Morveau
and Gren obiained a precipitate by combining this salt with
phosphoric acid: but [ think I'can on good grounds con-
clude, that neither of these chemists made their experi-
ments with pure phosphoric acid.

XXV. Deseription of a New Safety-Piston for Papin’s
Digester, with the Application of it to the Boilers of
Steam-Engines, and also of an Apparatus for regulating

_ the Heat of Furnaces. By A. N. Eprevcranrz, Knight

of the Swedish Order of ihe Polar Star, and Member of

several Academies and Learned Socicties.

, To Mr. Filloch.
SIR,

‘Ackuraniy to your desire, I have-sent you the description
of a safety-piston which I have employed in Papin’s:di-
gesters; the use cf which I have endeavoured to’ render
more exact, safer, and more convenient *. This small ap-
paratus, attached to the cover of the digester, consists of a
brass cylinder a l, fig. 2. (Plate III.) in which a piston of
the same metal, c d, moves with very little friction, in order
that it may descend by its own weight after it has been
raised up, without however permitting the vapour to, pass
between it and the cylinder. The Idwer part of the cylin-
der communicates with the digester, and is covered by a
small sphere, s,s, perforated with holes, to prevent the
matters in a state of ebullition from entering the in-

* The description of my piston may be seen in the Yournal de
Poysique, vol. lvi. pe-14.7. But since that time 1 have made some change
in its construetion. ,

side

~ for Papin’s Digester. 163

tide of it, but allowing the vapour to pass. The upper
part (a) is closed by.a small cover screwed on to it, and
perforated with a hole through which the piston-rod passes
easily. This cover’ serves the double purpose of guiding
the rod, and preventing it from being blown oul, The
piston-rod is furnished with a shoulder, g,g, which serves
to support different weights; vuv, which can be changed at
pleasure. In the side of the cylinder there are holes, e, e,
as small as possible, placed above each other at the distance
of about a line; but this distance, as well as the number of
them, is a matter of indifference.

To give an idea of the effect of this small apparatus, let
us suppose the piston jowered, and loaded with, any weight,
and that a fire is kindled under the boiler. When the va-
pour has acquired sufficient elasticity to raise the weights,
the piston will ascend, and, having passed the first hole,
some yapour will escape. If this aperture: be of sufficient
size for the passage of the quantity of vapour continually
produced, the piston will remain there stationary, and in a
state of oscillation ; if not, it will ascend above the second,
third, &c. hole, and, if the intensity of the fire is sufficiently
strong, above the Jast, which must be made larger, that, by
giving the proper means of escape to the vapour, all acci-
dents may be prevented. It is here evident, that though the
greater or less elevation of the piston, as well as the num-
ber of the holes open, depends on the variations and dif-
ferent intensities of the fire; these variations, however,
have no influence on the interior heat, and the elasticity of
_ the vapour contained in the digester, since their force is al-
ways proportioned to the weight with which the piston. is
loaded, and which is constant. This safety-piston seems
likely to afford, for delicate experiments, greater exactness
than the usual safety-valves, with or without levers charged
with weights, hitherto employed. For, in the whole course
of the space which the cylindric piston passes over in as-
cending, the state of the elasticity of the vapour is the
same; whereas, when the conical valve in common use Is
once raised up, nothing indicates whether, or how much,
the present state of the vapour surpasses the first effort it
made to open a passage. Besides, the diameter of the piston
being once known, the force of the vapour requisite for
each experiment can be easily regulated and determined.
If we suppose, for example, that the lower surface of the
piston is ~;th of a square inch, each ounce of weight on the
‘shoulder, g, will be equivalent to the pressure of a pound
on cach square inch of surface, and so on in proportion,

L2 As

164 Description of Mr. Arthur IWoolf’s Steam-Valve.

As this pressure then remains constant, the experiment
will be more determinate, and consequently more com-+
parative.

The application of this piston to the builers of steam en
gines needs no further explanation, except that, in this
case, the diameter of the piston must be considerably im-
creased. It seems here to offer the same advantage of

greater uniformity in the force of the steam, especially if ~

the motion of the piston be employed to regulate the fire
of the furnace, and to prevent the useless dispersion of the
vapour, by preventing an excess of intensity in the fire.
For this purpose, the following apparatus may be used.
Let m,n, fig. 3. be the aperture of the conduit for the cur+
rent of air which maintains the combustion of the fuel,
and 0,p, @ register; which, by rising or falling, opens of
shuts that conduit. If the motion of the safety piston be
combined by any means with the register, in such a man-
ner that, when the former ascends, the latter descends, so
that when the piston is at its greatest elevation the register
shall be entirely shut; it is evident, that, since the heat pro-
duced depends on the access of the air, the elasticity of the
vapour being determined by the weight of the piston, will
not only remain within the bounds prescribed for it, but
will regulate itself, by preventing more air from entering
into the furnace than is necessary to maintain its force.

T do not know what obstacles may occur in the applica-
tion of this apparatus on a large seale; but it seems to pro-
mise a greater saving of fuel, since, instead of throwing out
to no purpose a superabundant quantity of vapour, it wil
prevent its production, without expending any considerable
part of the force of the machine for that purpose.

SSS SSS

XXVI. Description of Mr. Arraur Wootr’s
Steum- Valve.

Tx our last we laid before our readers an account of Mr.

Woolf’s newly invented boiler, in which we mentioned

that, besides employing safety-valves, he had introduced a
valve of a new construction to regulate the quantity and
power of the steam passing from the boiler. We shall now:
lay before them a description of this ingenious contrivance.,

A (Plate TV.) ts a part of the main cylinder of one of
Mr. Woolf’s boilers; BB the neck or outlet for the stcam,
surmounted by the stcam-box C, which is joined to the neck

BB by

—-s

Description of Mr. Arthur Woolf’s Steam-Valve. 165

BB by the flanges aa. The top or cover of the steam-box
€, marked with the letter D, which is well secured in its
place, has ahole through it for the rod of the valve, so con-
trived as to answer the purpose of a stuffing-box to make
the rod work up and down steam-tight, the stuffing being
kept in its place by the usual means, as shown in the section.
By means of a pin or nail, J, and the two vertical pieces ee,
the piston rod is made fast to m, which is a cover of. and
joined to the hollow cylinder z,”. The cover m fits steam-
tight into the collar 0,0, which is made fast on the flangeaa.
~The eylinder m7 is open at the bottom, having a free com-
munication with the main cylinder A, and has three vertical
slits, one of which, S, is shown in the plate*. The sum of
the surface of all these slits or-openings is equal to the area of
‘the opening of the collar 0,0, in which the cylinder 2,7 works.
When the steam acquires a sufficient degree of elastic force
4o raise the valve (that is, the cylinder 2 with its cover m,
and therod R) and whatever weight it may be loaded with, then
the openings S, getting above the steam-tight collar 0, 0, al-
lows the steam to pass into the steam-box C. The quantity
of steam that passes is proportioned to the elastic force
it has acquired, and the weight with which the valve is
loaded ; and the rise of the openings S above the collar 0, 0
will be in the same proportion. This valve may be loaded
in any of the usual methods ; but Mr. Woolf prefers the one
shown in the drawing, in which the upper part of the rod
R is joined by. means of a chain to a quadrant of a circle
O with an arm projecting from it, as represented in the
plate, and which carries a weight, Z, that may be moved near
to or further from the centre of the quadrant, according as
the pressure of the valve is wished to be increased or dimi-
nished. As the valve rises, the weight moves upwards in
the arch 7, giving an increased resistance to the further
rising of the valve, proportioned to the greater horizontal
distance from the centre of Q, which the weight attains by its
rise in the said arch, the said distance being measured in
the line Op by a perpendicular from the said line Op
passing through the centre of the weight. Thus, if the
weight Z press with a force equal to twenty pounds on the
square inch of the aperture in 0,0 in its present position,
it will, when it rises to the position at 7, press with a
force equal to thirty pounds, and at p with a force equal
to forty pounds, on the square inch; so that the rod
©Z may be made to serve at the same time as an in-
>

* These openings may be covered with a grating.
L3 dex

166 Description of a ‘Portable Chamber Blast-Furnate.

dex to the person who attends the fire, nothing more being
necessary for this purpose than to graduate the arch de+
scribed by the end of the rod Q Z. In the side of the
steam-box C there is an opening N to allow the steam to
pass from it by a pipe or tube to the steam-engine, orto any
secondary boiler, or for the purpose of conveying and ap+
plying it to any other vessel or use to which steam is appli-
cable.

Before dismissing this article, we must beg our readers to
correct an error in printing the description of the boiler in
our last number, page 41. ‘The second line from the bottom
should read ** not. joined to any of them, excepting the
middle one, at the points,” &c.

XXVII. Description of a Portable Chamber Blast Furnace.
By C. R, Arkin, Esq.

DEAR SIR, To Mr. Tilloch. "

Some of my chemical friends having expressed their ap-
probation of a small portable blast-furnace which my bro-
ther and myself have been in the habit of using for a
variety of experiments on a small: scale; I am induced to
send you a description of it, in hopes that it may prove as
serviceable to others as it has been to us. It is particularly
adapted to those who, like myself, can only devote a small
room and a moderate share of time to these pursuits.

Dr. Lewis in his Commerce of the Arts (page 27) de-
scribes a very powerful blast-furnace formed out of a black+
lead pot, which “ has a number of holes bored at small di-
stances in spiral lines all over it, from the bottom up to
such a height as the fuel is designed to reach to.” This is
let half way into another pot, which last receives the nozzle
of the bellows, so that all the air sent in is distributed
through the spiral holes of theupper pot, and concentrates
the heat of the fuel upon the crucible, which is placed in the,
‘midst.

The furnace which I am going to describe resembles very
closely this of Dr. Lewis; with this difference, however, that
the air-holes are only bored through the bottom of the pot,
and this merely stands upon another piece, instead of being
let into it. It 1s on this account somewhat more commo-
dious, and I imagine not less powerful. .

Fig. 1. (Plate V.) is a view, and fie. 2. a section of the

_ furnace.

’

Description of a Portable ‘Chamber Blast-Furnace. 167

furnace, It is composed of three parts, all made out of the
common thin black-lead melting-pots sold in London for
the use of the goldsmiths. The lower piece, A, is the
bottom of one of these pots cet off so low as only to leave
a cavity of about one inch, and ground smooth, above and
below. The outside diameter over the tep is 5}inches. The
middle piece or fireplace, B, is a larger portion of a similar
pot with a cavity abeut six inches deep, and measuring 74
inches over the top, eutside diameter, and perforated with
six blast-holes at the bottom. These two pots are all that
are essentially necessary to the furnace for most operations:
but when it is wished to heap up fuel over the top of a cru-
eible contained within, and especially to protect the eyes
from the intolerable dazzle of the fire when in full heat, an
upper pot, C, is added, of the same dimensions as the mid-
dle one, and with a large side opening cut out to allow an
exit to the smoke and flame. It has also an iron stem with
a wooden handle {an old chisel will do very well), to lift it
off and on.

The bellows.(which are double) are firmly fixed, by a
little contrivance which will take off and on, to a heavy
stool, as.is represented in the plate; and their handle should
de lengthened, to make them work easier to the hand. To
increase their force on particular occasions, a plate of lead
may be tied on the wood ef the upper flap. The nozzle is
received into a hole in the pot A, which conducts the blast
into its cavity. From hence the air passes into the fire-
place, B, through six holes, of the size of a large gimlet,
drilled at equal distances through the bottom of the pot,
and all converging in an inward direction, so that, if pro-
longed, they would meet about the centre of the upper part
of the fire.’ The larger hole through the middle of the bot-
tom of the same pet is for another purpose. Fig. 3. 1s a
plan of the.same, showing the distribution of these holes.

As a stand or support. for the crucible, I have found no
micthod so good as to fit an earthen stopper into the bottom
of the pot B, through the large centre hole which is made
for this purpose. This keeps the crucible in its proper
place, in stirring down the coals and managing the fuel.
These stoppers are made with great ease and expedition out
6f the soft red fire-brick sold in London. A piece of this
brick, made to revolve a few times within a portion of iron or
earthenware tube, presently takes the form of its cavity, and
comes out a very neat portion of cylinder or cone, according
to the shape of the tube, from which the stoppers may rea-
daily be fashioned, Fig. 4. represents one of these stoppers,
: L4 which

168 Description of a Portable Chamber Blast-Furnace.

which is also seen in its proper place in fig. 2. supporting 4
crucible. A att

As the construction of this furnace (exclusive of the bel-
lows and its stool) is easy to any one at all used to these
little manual operations, [ trust that the working chemist
will allow me to add a few words on the method which I
have found the most convenient and-ceconomical. Almost
any broken pot of the,proper width will furnish the lower
piece A; and often the middle and upper piecés may be
contrived out of the same refuse matter. Dr. Lewis ad-
vises a saw to cut these pots: but most saws are too thick ;
and when a little used, the teeth get. rounded off, which
‘makes them work intolerably slow. I have found by far
the best tool to be an old table knife (or rather two of
them) worn thin by use, and hacked and jagged as deeply as
possible by striking the edges strongly against each other.
These work well and expeditiously, and when they become
dull are again roughened by the same simple means. The
holes may be drilled with a common gimlet of the largest
size, and a little steadiness of hand will easily enable the
operator to give them the oblique direction with sufficient
accuracy ; for much is not required. To make a smooth
surface to the parts intended to adapt to each other, first
Wear them down a little with the soft fire-brick, and then
grind them with water on a flat free-stone (a sink-stone for
example), and lastly make them entirely fit by rubbing one
surface on the other.

No luting of any kind is ever required ; so that the whole
may be set up and taken down immediately. Nor is it ne-
cessary to bind the pots with metal hoops; fer they are
thick enough to endure considerable blows without break-
ing; and yet they will bear, without cracking, to be heated
as suddenly and intensely as possible. In short, the black-
Jead crucible seems to be the best material that could pos-
sibly be devised for these purposes.

The heat which this little furnace will afford is so intense,
and so much more than would at first sight be expected from
so trifling an apparatus, that it was only the aécidental fusion
of a thick piece of cast iron in it that led us to suspect its
power. The utmost heat which we have procured im this
furnace has been one hundred and sixty-seven degrees of a
Wedgwood pyrometer piece, which was withdrawn from a
very small Hessian crucible when actually sinking down in
a state of porcellanous.fusion. A steady heat of 150° to
155° may be usually depended on, if the fire be properly
ymanaged and the bellows worked with vigour. This is suf-

1 ficieat

Preparation of Howard’s Fulminating Mercury. 69

ficient for most operations in chemistry ; and the ceeconomy
in time and fuel is extreme, since a furnace of the given di-
mensions will very well raise to the above point of heat in
from five to ten minutes a Hessian crucible of such a dia-
meter, that the average thickness of burning fuel around its
bottom is not more than one inch and a half. “A smaller
crucible will take a higher heat, but at the risk of its soften=
ing and falling in by the weight of the incumbent fuel.

Coak, or common cinders taken from the fire just when
the coal ceases to blaze, and broken into very small pieces,
with the dust sifted away, form the best fuel for the highest
heat. A light spongy kind of coak, formed of a mixture of
coal and charcoal, called Davey’s patent coal, also answers
extremely well. Charcoal alone has not weight enough,
when broken so small as it must be to lie close in this little
fire-place, to withstand the force of the blast when very
violent. A bit of lighted paper, a handful of the very
small charcoal called in London smadt coal, and ten ora
dozen strokes of the bellows, will kindle the fire in almost
as many seconds.

Various little alterations and arrangements, which will
readily occur to the practical chemist, will fit this little ap-
paratus for distillation with an earthen retort, heating a
gun-barrel passed through the fire, bending glass tubes, &e.

I shall only add, that the dimensions of this furnace were
determined merely by the circumstance of having at hand
pieces of black-lead pots of this size, so that doubiless they
may be varied without any diminution, and probably with
some increase of the effect. The same may be said of the
number of holes; for in another instance four appeared to
answeras well as six,—with this difference, however, that, by
long working, the melted slag of the coak will now and then
partially block up one or two of the holes; on which ac-
count perhaps the Sreater number is preferable.

I remajn sincerely yours,
. C, R. Arxin.
Broad-strect Buildings,
Nov. 20, 1803,

—

XXVIII. On the Preparation of the Pulminating Mercury
of Mr. Howaron, ly Mr. A. S, Burxirr.

To Mr, Tilloch,
DEAR SIR,
oe at various times prepared the fulminating mer-
cury of Mr. Lloward, | was desirous to collect the gas
. which

170 Preparation of Howard’s Fulminating Mercury.

which escapes during the process, which I have done fre+

quently; but the last time I had occasion to repeat it with

more exactness than before. Should you think the result

worthy a place in your very valuable and interesting Jour

nal, it is at your service.
Fleet-street, I am, dear sir, &c.

Nov. 16, 1803. A.S. BurKITT.

1 took three ounces of mercury, which I dissolved in 14
ound of nitrous acid. When the solution was completes
{ poured it into asix-gallon retort, in which I had previously
put 1; pound of rectilied spirits of wine heated to about 80
degrees. I then introduced the neck of the retort into a
ten-gallon carboy which had by accident a hole broken in
its side*: the mouth of the latter was inverted in an earthen
vessel containing four pints of water (sce fig. 4. Plate III.).
In the space of three minutes the usual effervescence took
place; when a considerable quantity of gas was disengaged,
and condensed in the carboy. In about twenty minutes
ihe process was complete, and the precipitate formed. I
moyed the apparatus, and poured the liquor from the
precipitate in the retort, washed it well, and dried it upon
filtering paper. The produce was three ounces and one
dram of the fulmjnating mercury.

I then moved the carboy, and obtained upon the surface
of the water, in the earthen vessel, four ouyces of nitric
ether.

Not being in the habit of throwing any thing away un~
til I am satisfied it cannot be turned to account, I added
one pound. of spirit of wine to the water that had washed
the ether, and, by distillation in a common sand-bath, ob-+

y

tained from it one pint of sweet spirit of nitre, a
The preparation of the fulminating mercury is generally
conceived to be a dangerous process, but is not at all-so in
my opinion, as the precipitate will not fulmmate until it
bas been well washed. I have prepared it very often: once
I made nine ounces at one operation; but I never employ
heat, as I add the mercury in the acid as sgon as the solu-
tion is complete, which is sufficiently heated by the action
_of the acid upon the mercury, to the spirits previously
warmed to about eighty degrees.

* The fitting was completed by applying a wet rag round the neck
ef the retort,

Spinners Hes

a

KXIX. Tenth Communication from Dr. THoRNTON.
To Mr, Tilloch.

SIR, No. 1, Hinde-street, Manchester-square,
” Nov 20, 1803.

F Rom the inclosed case you will find that the cause of
Pneumatic medicine is not abandoned by me, as has been
circulated ; nor are its virtues less effectual now, than
when I first commenced its application m, the year 1792.
The inclosed case I have no doubt you will think with me
is a very striking instance of the superior efficacy of vital air
in removing a load of disease supposed incurable, such as
seldom falls to the lot of humanity. It is published, like the
many others I have before given to the world, at the express
desire of the patient, in order to extend, as far as our weak
but anxious endeavours can avail, the blessings of this in«
estimable and truly philosophic remedy ; and is brought for-
ward, I solemnly assure you, by me, not for any individual
advantage, but to rouse my medical brethren to. make trial
of similar means in cases that appear to be adapted to its

application, and which might otherwise remain incurable.

Case of Miss Margaret Gorst.

| Thisamiable young lady, daughter of the Rev. Mr. Gorst,
rector of Marton and Kirbythore, near Appleby, in the
North of England, had naturally a most excellent state of
health. Her eldest sister taking cold fell into a. declines
and constantly attending upon her, and sleeping along
with her, previous to her death, gave the first shock to her
constitution. Going after this upon a very hot summer’s
day into some lead mines possessed by her father at Dufton
Fell, she was struck with the damps ; and at the early age of
seventeen commenced her martyrdom to disease. Her appe-
tite forsook her, she had constant pain on the left side, felt a
continual lassitude, palpitation of the heart, and the feet to-
wards evening would frequently swell. The dyspepsia in-
creased to that degree that all animal food was loathed, and
when taken rejected ; and, in consequence, her support was
obliged to consist wholly of veectable food. Her limbs
were cold to the touch, and appeared blue even in the midst
of summer. Her nerves were in that depressed state, that
the smell of a candle badly snuffed, or a nosegay introduced
into the room, or even melted sealing-wax, would instantly
take away her voice, so that no one could htar her. If a.
door was suddenly opened, or from any unexpected noise,

she

172 Tenth Communication from Dr. Thornton.

she would tremble, and fall into a flood of tears. Her eyes
became sunk and inanimate. Her colour, before extremely
blooming, forsook her cheeks, and her whole complexion
appeared of a mahogany colour. Her bones were nearly
through her skin from emaciation, and she was obliged to
be carried in the arms of the servant from one room: to
another, having entirely lost all power over her limbs. She
was reduced to that state of lowness, that for days together
she would scarce notice any person, or even speak. The
daily inquiries that were made at the house, were not whe-
ther this young lady was better, but whether she was still
alive: and as tonic and stimulant remedies of every kind
had been ineffectually employed by the most skilful practi-
tioners of the country, all of whom had pronounced to the
family her recovery as a thing not to be looked for, she
was universally Jamented, as a person labouring under a dis-»
order that could not be removed, This melancholy state
had existed now more than thirteen years, when her bro-
ther *, who favoured me with the particulars of this melan-
choly case, from perusing the cures performed by vital and
other airs, recorded at length in vol. 1, of my Philosophy of
Medicine, as a dernier ressort applied to me for my advice 5
when I recommended the inhalation of the vital air. It
was begun September 14, 1802. From the journal drawn
up by the lady, I shall beg leave to make a few extracts. I
had ordered two quarts of vital air mixed with fourteen or
fifteen of atmospheric to be inhaled dajly, at two different,
jatcrvals.
Olservations,

‘* Feel faint and languid after each time of inhaling; but

this sensation soon goes off, and then I feel refreshed. I
experience a glow, and seem as if I was lighter.
“So pleased was I at feeling myself enlivened by this
quantity of vital air, that, contrary to.the direction given, I
doubled the dose; and after the ithalation in the evening I
was seized with the most dreadful ¢convulsive fit, which
lasted six hours, and | was in consequence confined to my
bed. So conyinced was I, however, that this fit, a thing
Thad never experienced in my life before, arose from an
overdose of the vital air, that I requested to have the pneu
matic apparatus brought to ny bedside, and with dithculty
could persuade my frightened relations to let me try the
medicated air again in a more cautious manner,

«© The amendment was by its continuance in this way so.

ne A ° v ;
* Mr. William Gorst, wine-merchanr, No, 14, Little Tower-street. i

P great }

t

by

Tenth Comniunicdtion from Dr. Thornton. 173

great, that it was visible to every one who noticed the altera-
tion in my looks, and my increase of strength. So far from
requiring assistance, I was enabled to walk out above a mile.
Instead of living upon vegetable I could take animal food,
which my stomach did not reject. Smells had no Jonger
any effect on my voice; so that after nine months, con-
tinuing the use of the vital air, I went to Hartlepool. The
sea air continued on the benefit; but after six weeks ab-
sence, thinking I could do without the vital air, upon my
return home [ omitted taking the air, and was relapsing
into my former weak state : but all the bad symptoms went
off upon my resuming again the vital air, which has now
been continued with the same advantage above a twelye<
month,”

Olservations on this Case, ly Dr. THORNTON,
This almost miraculous* effect from vital air furnishes
many curious reflections.

1. The disoxygenation, or want of vital air in the blood,
was shown by the sa//owness of the complexion, and bive-

ness of the extremities; their coldness; the torpor of the

*

be

bowels; want of energy in the nerves of the stomach, and
total /oss of muscular powers, without paralysis.

2. The disappearance gradually of all these symptoms»
which had existed upwards of thirteen years, from the in-
halation of a swperoxygenated air, proves, or seems to prove,
in the strongest manner the powerful influence of vital aif
on the animal ceconomy. The complexion became clear ; the
cheek acquired its vermilion; the jizgers no longer appeared
blue; a general warmth was diflused ; the stomach digested
animal food; the doweds performed their daily office with~
out the aid of medicine (before, they used to be suffered te
go unrelieved eight or ten days, as the mildest purgatives
produced always dreadful swoonings); the muscles ac-
quired their energy, and the merves their influence. No
other medicine was employed here but tincture of colombo,
which had before been long uselessly exhibited.

* Old Dr. George Fordyce used to say, speaking of the faciitious airs,
* As tous, we don’t perform miracles.” I might have said, Nor do the
pneumatic physicians : they record upon the accredited testimony of others
the effects saidto be felt, and by multiplying similar evidences they are
in hopes finally of settling legitimate conclusions. They esteem it as the
fairest plan to record what they are cold, and leave to others to disprove
@r approve, by making themselves trials under somewhat similar cir-
‘eumstances. They reckon this-scienee still as in its infancy, and would
wish to see it advance by the combined cilorts of many practitioners,
friends wo science-and mankind,

3. That

174 Tenth Communication from Dr. Thornton.

3. That the superoxygenated air is not an énert power, is

shown by its producing in an overdose, in a weak habit, @
dreadful convulsive fit; which was not the ease when emi-
ployed afterwards in a Jess proportion. 1 have before re-
corded the case of a lady subject to epileptic fits, which had
ceased six months, ath which recurred inmediately upon
the inhalation of the superoxygenated air (vide my Philo-
sophy of Medicine, case xi. page 475) ; also a very wonder-
ful case as recorded by the ingenious and indefatigable Dr.
Beddoes, (vide Philosophy of Medicine, case x. p. 474.*)

4. The proportion being diminished, the same good arose
as before; which shows that this remedy requires some
gudgment in its exhibition.

5. That the air absorbed by the blood in the lungs influences
appetite and digestion, is known by such who expose them-
selves to-the sea air, the air of mountains, or even the air
of a field; which usually creates an appetite.

6. That such, but in a superior degree, is the effect of a
superoxygenated air, is a general remark. Mrs. Lowry,
wife to a well-known eminent engraver employed in your
magazine, a lady endowed with a most excellent under-
standing, recollects what others have told her; and from her
journal [ can collect, that upon inhaling the superoxyge-

* nated

_ * Mr. Davy, lecturer on chemistry at the Royal Institution, certainly
-one of the most enlightened philosophers of Europe, found, afver breath-
ing the pure oxygen or vital air, that his respiration became */aborious,
and his pulse barder,—*‘ effects as though a less quantity of oxygen was ab-
sorbed by the blood” (see ResearchesChemical and Philosophical, chiefly
concerning Nitrous Oxide, p. 473): but this could not be the fact, for the
following reasons: In given proportions of common and vital air, anani-
mal will live four times longer in the latter than in the former; and so
increased are the actions of life, that in animals made to breathe the pure
vital air, the liver after death will be found so far oxygenated as to lose
its liver-colour, and appear florid ;, marks of inflammation will every
where. be discoverable, and the death produced on the animal will arise
from an excess of life. That the absorption of oxygen is greater than
when breathing common atmospheric air, is shown from the following
accurate experiments by my late ingenious friend Dr. Ingenhousz:

Thirty cubic inches of vital air was put into a dry bladder, and all ©

drawn into the lungs, and ejected, and so employed for several times.
The resu!t was,

ie ses A E 4 wonr ego m
The proof of vital air was 0-78, 0-48, f Sgeuad QPS
O28, 118 - = a -7.8 > Fy a8) S Bs 382
After the nrst inhalation, o-S0, 0°60, 160 | wo" 8 2S E 2 FS 240
After being breathed a second time,< 3 » «= Gees 8
. A uv e *
O75, 116, 2°15 - - - - 2858 e2 25852 as
After the third time, 0°86, 1°86 . - | REC R? Sh yw oe 114
} . . pe = oe » 2 16 ee [ran
After the fourth time, 1°21 Soi =eebnesu 19

Tenth Communication from Dr. Thornton. 175

nated air, it created so stronga sense of hunger, that,
as she was returning home, she could not refrain from going
into a baker’s shop, baying, and eating up directly, two
penny rolls. Afterwards she came with a supply of bis-
cuits; which plan was followed at the same time by some
other patients *.

7. The sea air at Hartlepool kept up the advantages of an
artificial inhalation of a superoxygenated air. That there
is more vital air in sea-air than in-land, has been proved
by a very ingenious paper by Dr. Ingenbousz, presented be-
fore the Royal Society. Most of the advantages of going
to the sea side arise from this cause {, instead of bathing.
How much more easy the expense of artificial inhalation of
a superoxygenated air, if the advantages are the same, than
distant journeys to those remote from the coast for the re-
covery of health! This idea is worthy of some conside-
ration. ,

The examination of common air was as follows: .

The common air by proof was 7S =
106 - - - Be ed a Oi
Aft sgoeualiar’ yl Biug igre euonugs
er one inspiration, 1°25 me SS 73
After the second, 1:27. = SeoxQ - 63
After the third, 1°47°> = ve VTS 53

pea
After the fourth, 1°48 - H&22 3) -) 52

* The bardvess of the pulse and the d@culty of breathing in Mr. Davy,
after inhaling the pure vital air, seem then to have arisen from a degree
of inflammatory fever having been induced ; or by taking backwards and
forwards the same air too often. To aphilosophic mind this is no objec-
tion; or-that animals are destroyed by pure vital air, dying from an excess
of excitement; for the most potent poisons are the best remedies, when
judiciously employed.

* This effect might be contradicted by future experience on a small
scale, especially upon healthy individuals. Let the reader, therefore, be
acquainted, that Mrs. Lowry at first came to me ina coach, and could
not support herself upright. She had been given up by the most able
practitioners. As strength returned, appetite increased: and this is ever
as the wants of the system: after a recovery from a fever every one must
have experienced the cravings of nature, and her state was soon that of
convalescency. ‘So predisposed, it is not to be wondered at if the oxygen
produced a circumstance at which some may smile; and I have added
this note, fearful of a contrary account being hastily published by an ex-
periment made upon persons in the vigour of life.

+ This ingenious memoir on the degree of goodness in the air ¢that is,
the proportion of vital air to azote,) as found on the open sea, on the sea
side, and at a distance from the sea, was read April 24, 17203; and is
published in vol. lxx, of the Philosophical Transactions.

{| The surprising cures recorded by Dr. Gilchiist, and others, from
long sea voyages, must have partly proceeded from this ciecumstance.
The increase of appetite in short sea voyages has. Leen noticed by me
more than once, and by others.

a 8. That

176 = Tenth Commitnication from Dr. Thornton:

8. That muscular power was restored. Mrs. Lowry cares
fully noted, at my desire, the number of steps she took in
coming to my house, and upon returning atter the inha~
Jation of a superoxygenated air; and she found that the
number required upon return was reduced nearly one-third.
If you notice the pavior :—before he strikes in the stone
he forcibly drives out the air in his lungs, takes ina full in~
spiration, and then uses his powerful exertion. The panting
for breath shows the use of this principle in the blood for
exercises”

9. The whole frame had a deadly cold, and the fingers
looked blue. The Promethean fire inspired i into the man of
clay, to those fond of interpreting of antient hieroglyphics,
T would say was no other than vital air; which contains,
and imparts to the body, the animal heat. ‘* And he
breathed into him the breath of life.’? Mosgs. In:the
blood is the life ;”” (the breath of life, the vital air ;) there-
fore (inreverence to this principle) ** Thou shalt not eat the
blood.” Moses.

10. That the voice was no longer taken away by smells.
This j is a curious fact, and shows the influence of the vital air
in giving energy to the muscles of the larynx. I could
mention, that a certain great actress upon inhaling the vital
air found the power of her voice perceptibly mereased ;
ali her lower tones were in every part of the house distinctly
heard, and a person was appointed by her purposely to as-
certain this fact. The voice is always found stronger by
the sea side

it. When the blind boy recovered to sight was asked by
the Jews about it, his answer was, “ I know before I was
blind, vow I see.” So of those who have been recovered
by the vrran arr, before they were thought incurable, now
they are cured. These attribute the effect to the cause +
why should medical gentlemen then hesitate making an
experience for themselves? There is no concealment of
names, or of the remedies at the same time employed,
or any thing above plain reasoning. Mr. Watt of Bir-
mingham has kindly contrived a simple apparatus fot
making the vital and other airs *; the process 1s easyf. A
pneumatic apparatus for ao the airs is cheapf. Ar
tificial air may be conveyed to any part of the world tm

® This costs, to fabricate the airs, three pounds.

+ This is described by me, with a figure of the apparatus by Mr.
Lowry ry Vol. i page 347, of my Philosophy of Medicine, A pound ‘of

ai anese will yield 20 quarts of vital air, and a hundred weight of
mag ar is sold in London for 18 shillings
\ tin apparatus cost’ abot thirty shillings,

. barrels

‘
:

Tenth Communication from Dy. Thornton. 177

barrels, and bottled off as wanted, like wine; the shrine
of Diana is not in danger, as other remedies may and
should be exhibited at the same time: it does not interfere
with them; but, on the contrary, gives them power,
whereas without it they have no basis to act on*: in the
exhibition of the pneumatic remedy there 1s neither danger
if used with precaution, nor disgrace in trial; the harvest of
discovery is wide, the only want is harvest-men.

I shall conclude with the following energetic appeal by
Dr. Fourcroy + to the faculty at Paris on this subject:

« Tt cannot any longer,” says that emiment chemist
and philosopher, “‘ be permitted to the physician tq temain
an inactive spectator of the power of gaseous bodies on the
animal economy. No professional man, if he is at all in-
terested in the advancement of his studies, if he is at all
animated with a proper zeal for the progress of medicine,
can any longer neglect to instruct himself in the conclusions
of modern discoveries t. The cold statue-like insensibility
of some, the affected indifference of others, the sneer ut-
tered by this man, the irritated self-love of the other, the
attachment of mankind for the doctrines of their fathers,
the hatred of novelty, prejudiccs of every kind, all the
mean passions which glide into society, playing their part
on the theatre of civilized life, are to be found also in the
career of science: the excesses which these have produced ;
the pleasantries which they give rise to; the sarcasms, or
epigrams, with which they arm discourse; the ridicule which
some have endeavoured to throw on the inventors; the epi-
thet of innovators, of which they are prodigal ; all this may

* The philosophy of the da/ance of principles (HyDROGEN and
OXyGrN) in the body is a wonderful consideration for the contempla-
tion of the man of science and the physician. As fire burns not so much
from the fuel poured on, as from the air without, so has this external
principle a greater effect on us than most people are aware of. The
oxygen air, or vital air, acts as a bellows tothe frame. The fire, which
was once bad, being kindled up by the bellows, maintains afterwards its
own blaze; so the ws wite, energy of life, being roused by the inhala-
tion of viral air, afterwards keeps up its own natural inherent vigour. .
This comparison is made for such who will not receive facts as they are
recorded, and will allow no virtue in vta/ air, as not being inhaled ail
day long. What would we say of the practitioner who was ordering
bark every five minutes, or wine?

+ This fine appeal is at the commencement of an essay which this di-
stinguished chemist and physician read in the School of Medicine at Paris,
on the medical virtues of oxygen; and the whole essay is given in the
28th volume of the Annals of Chemisty.

t A physician of considerable practice and estimation was lately con-
sulced abour the oxygen air; when he assured the patient that it did not
om apply to his case, as he was a/ready too much filled With air (fa-
tulent)! !

Vot, XVII. No. 66. M retard

178 Instruments alluded to in this Essay-

retard for some few years the progress of new ideas: but
truth will overcome every obstacle ; she cannot be frightened:
either by the clamours of envy, or the resistance of preju-
dice, or by the opposition of ignorance. She is the rock
against which the impotent billows of human passions are
broken. The cry yet vibrating in our ears against the cir~
culation of the blood, the use of antimony, and the i inocu~
lation of the small-pox , could not hinder these discoveries
from being finally established. Tt will turn out exactly the

same with the new chemical discoveries,. when applied to
illustrate the functions of the animal ceconomy.”

“‘ Its career so gloriously begun will never stop» I do
not in the least hesitate to pronounce,” he continues, ** that
modern chemistry has done more im a few years for medicine,
than all the united labours of physicians in all the preceding
ages. Only contemplate before this period what has been
written on the motion of the blood, the blood itself, the
nature of respiration, oi animal heat, perspiration, diges-
tion, and irritability ; examine the’ shbtle and ingenious ‘hy-
potheses on these ‘subjects, which appear at this time so
degrading to the human reason; let even the immortal
Haller be tried by this test, whose facts are so- valuable, but
whose hypotheses are altogether a mere mass of dark and
futile reasonings ; and we shall perceive how much we are
indebted for the new lights throw n in by ehemistry, and
how much we have yet to expect.” Tyremain, sir,

Your obedient humble servant,
RoBERT JOHN THorNTON.

P.S. Hf any medical gentleman would favour Dr. Thorn-
ton arin the result of any trials with the factitious airs, they
will be communicated to the Editor, for the philosophic
world.

[These Communications are intended to le continued.]}

XXX. Br. Crose’s Communication to the Board of
Agriculture.

[Concluded from our last volume, p. 60.]

An Account of the Instruments alluded to in this Essay~

il ik instruments alluded to in this essay are, the common
Suffolk plough without any wheel, worked by two horses
and one man: this implement is too well known to require
a description. Mr. Cooke’s drillis an instrument which will
deposit any quantity of seed per acre, at any given depth,

with intervals of nine, eleyen, or eighteen inches, two,

-

5 three,

Instruments alluded to in this Essay. 179

three, or four feet, with mathematical exactness 3 so that,

wherever it should fail of success, the failure must not be

attributed to a defect in the machine, but to the ignorance,

or more frequently the obstinacy, of the person who works

it. I have tried it with success in all soils: the utility was

most apparent; I should without hesitation say, in strong

clays and clayey loams: - To obtain a fine tilth on the sur-

face of the soil, in the spring of the year, when the plants

are growing, is indispensably necessary. This, should an

incrustation be formed by heavy rains and sudden droughts,

may at all times be secured by the use of the fixed harrow,

scarifiers, and hoes: The cultivator is another instrument

for which the agricultural part of the nation is indebted to

the ingenious and very superior mechanical knowledge of
the same gentleman: It consists of a diagonal beam with

seven narrow shares, ard when used with these it is called

a tillage scarifier: there are also five broad triangular shares,

which may be fixed in the same beam, and with these it is

termed a scufHler: the whole complete forms the cultivator.

The scarifier may be used with three, four, or seven tines

or teeth, according to the cleanness or foulness, the loose-

ness or tenacity of the soil. It is calculated to pulverize

the soil, and to cleanse it from quitch grass. In short, it

in a great measure supersedes the necessity of the plough.

In tilling land, the objects are to pulverize, to expose, to

cleanse from weeds, and to ridge up for keeping the land
dry and healthy, atid for sowing. These are the desiderata,
and all of these, except the last, may be most completely:
“uttained, at half the usual expense, by the use of the til-

lage scarifier. To secure a garden tilth on the fallows with-

out much expense, scarify the stubbles twice, deep and well,

soon after harvest; with half a ploughing lay the land on to
three-feet ridges before Christmas ; reverse them in Febru-

_ ary, and after barley-sowing sled or harrow down the tops;
roll and scarify alternately until you have a very highly pul-

verized soil seven inches deep. Form your three-feet ridges,

and drill your'turnips. The scufflers, or broad shares, are

to skim the land and destroy the surface weeds. The fixed

harrow is also a most excellent instrument, and, without

the use of any other implement, will prepare land that was

ridged up betore Christmas for any spring-corn crop. It

pulverizes the surface which has been exposed to the frost

four or five inches deep, without turning up the cald sterile

land below that depth *,

* The scarifying harrow is admirably calculated to pulverize-crogs in
an carly stage of their growth, as it will pass in the nine- or eleven-inch
intervals without injuring the planrs.

M 2 Al)

1so Instruments alluded to in this Essay.

All these instruments may be considered as appendages
to the drill, all may be applied to the same axis and wheels +
and as all of them are worked and direeted by handles, by
more or less pressure the depth may be regulated at plea-
sure. As I have been applied to by many gentlemen from
various parts of the kingdom for information as to the num-
ber of these instruments, and horses requisite to cultivate
any given quantity of land, I'shall take this method of
stating to the Board my ideas on this subject. For keeping
one hundred acres of arable land in high tilth and regularly
cropped, five horses would be necessary, two Suffolk ploughs,
one cultivator eomplete, one beam and handles, with only
the tillage scarifiers, one fixed harrow, and one drill with
corn scarifiers, and a set of flat hoes. F should also recom-
mend two pair of wheels with axis, independent of the drilk
wheels, which I could never use but for the purpose of drill-
ing, except on very particular oceasions. It is unnecessary
to say, that one strong waggon and one light harvest ditto,
with three dung carts, would be necessary; one common
pair of harrows, and two rollers, (one very heavy, and only
tive feet long, to follow the scarifiers,) and one common
roller for passing over the corn in the sprimg of the year.
Though an instrument not alluded to in this essay, I should
strongly recommend Mr. Cooke’s chaff-cutter, with which
I cut almost all the straw raised upon my farm, which is
applied to the purposes of animal food, and by passing
through the stomachs of the beasts is converted into strong
manure ; one load worth three such as is usually made in
yards, which is little better than wet straw. I derive great
advantage also from a boiler invented by Mr. Cooke, which:
saves two-thirds of the fuel. By atub over this boiler I
steam seven four-bushel bags of potatoes or turnips with
three pecks of coals. A thrashing machine, capable of being
removed easily from one barn to another, appears to me a ~
desideratum. The quantity of corm which might be saved
by a complete machine of this sort would be of real national
unportance. Though the cultivator and fixed harrow may
be considered as appendages to the drill, yet they are ap-
plicable to the broad-cast husbandry, and would save, if gene-
rally used, more than half the common expense for tillage.

Upon Drilling and Horse-hoeing.
Drilling is an operation which requires but very little
attention. On this subject I shall only state the depth at
which the seed should be deposited, the quantity per acre,
and the width of the intervals, which appears to me, after
fourteen or fifteen years practice, to be the most eligible.

Many

Upon Drilling and horse-hoeing. ‘181

Many crops of wheat have been greatly injured by deposit-
ing the seed too deep, especially in wet soils: a little at-
tention to the principles of vegetation will demonstrate this.
Nature is uniform in her operations ; and whether the seed
be put into the earth at four, three, two, or one inch below
the surface, the roots, which are to carry the corn to per-
fection, will be formed at one precise depth and very near
the surface. Wheat has two sets of roots, which may be
termed the seminal and coronal: the first come from the
grain, and the others are formed in the spring from the
crown of the plant; they are united by a tube of commu-
nication, by which the plant is supported until the coronal
roots are formed. By depositing the seed too deep, it fre-
quently perishes by a superabundance of moisture ; and cer-
tainly from its increased length this little thread-like tube
is more liable to be cut asunder by the red or wire-worm.
This theory is confirmed by practical observation ; for in
the spring of the year I have frequently taken up plants of
broad-cast wheat, and always found that those which ap-
peared most luxuriant had been covered by-not more than
an inch of mould, and those which had fallen into the fur-
rows, and were three or four inches below the surface, had
a very sickly appearance, with a small blade of a bad colour,
and making no efforts for tillermg. From this theory,
strengthened and confirmed by observation, I conclude that
an inch is the best depth for depositing the seed of wheat.
The same observations will apply to oats, barley, and rye,
all plants which form their coronal roots near the surface.
I should recommend wheat, barley, oats, vetches, and rye,
on soils not very wet, to be drilled on five- or ten-feet ridges,
in equidistant rows of one foot. Beans, pease, and turnips,
on three-feet ridges, two rows on a ridge, nine inches from
row to row, with intervals of twenty-seven inches, _ Lands
in high tilth, and on five-feet ridges, will require only three
pecks of seed wheat or rye; five pecks of oats, barley or
vetches, and one bushel of beans or pease, per acre, and
half a pound of turnip-seed on the three-feet ridges, vary-
ing a peck an acre, according to the goodness of the seed
and the richness of the soil. For scarifying, and horse-hoe-
ing, some attention and judgment will be requisite. No
corn should be scarified until the spring of the year. Pul-
verize the surface by passing the fixed harrow across the
_wheat previous to scarifying, to break the incrustation on
the surface, lest the scarifiers should throw large flakes of
earth over the rows of corn. After this operation, pass the
scarifiers through, about an inch below the surface, return-
/ Ms ing

184 Upon Drilling and Horse-hoeing.

img in the same track, as deep as the land was ploughed ;
then roll with a heavy roller, which will give the whole
land a concussion, and pulverize it six inches below the
surface, allowing the tender roots room to expand in a fine
bed of vegetable food. In short, care must be taken not to
throw any earth up to the plants in this early stage; for, as
nature always forms the coronal roots at the most advan-
tageous depth below the surface of the soil, by throwing
earth to the plants you impede her operations, and she
will, by a sort of vegetable instinct, be obliged to form
fresh coronal roots. If have known the progress of vegeta-
tion much retarded for want of this precaution; and nature
has laboured so steadily ta rectify the errors of man, that
sometimes three sets of coronal roots have been formed,
those beneath dying as the joint at the proper distance below
the surface sends out new ones. When these operations are
oe Ga with judgment, the advantages are beyond calcu-
ation. The scarificrs and roller moving all the soil, without
earthing up, give the roots room to expand, and assist the
operations of nature : the tillering will be greatly increased *,
and all the offsets ripen at the same time; and by earth-
ing up the plants when the ears are risen six or seven inches
anove the surface, a plump and fine sample will be secured,
and no more offsets can be formed. Rolling will be inju-
rjous when the ears are risen above the surface. These pre-
cautions are only necessary with wheat, and the white corn
crops with coronal roots: with pease, beans, vetches, and
all tap-rooted plants, no injury can be sustained for want
of such attention, Never attempt to perform any of these
operations until the Jand be dry; and be sure to keep a fine
uilth on the surface of your lands four or five inches deep
in the spring, whilst the plants are in a young and growing
state. Were this new system universally adopted, the sav-
ing in seed corn would be of the utmost national conse-
quence ; certainly not less than eight million bushels of
rye, three million bushels of barley, four million of oats,
and one million of pease and beans. This statement does
not amount to the full quantity which might be saved. This
last autumn. more than a sixth part of the scanty crop of
wheat was thrown ito the ground for seed. Such are the
times, that the noblemen and gentlemen of landed property
must considerably increase their rents, or they cannot hold
their situations in the scale of society. To answer this de-

* I have counted one hundred and one stems of barley, all likely to
arrive at perfection, from one seed. * nite
Sr F mand,

Estimate letween Grass and Arable Lands. 183

enand, and the additional expenses upon every agricultural
instrument, the rise of poor rates and the high price of la-
bour, the farmer must receive at least one-third more from
the produce of his farm. Should this be effected by such
an additional price on the articles of necessary consump-
tion, the wages of our manufacturers must be such as te
oblige us to give up all competition in foreign markets, end
our trade will decline. But [ am thoroughly convinced that
the landlord may enjoy his increased rent, and the farmer
not only eat the fruits of his own labours, but acquire
a‘competency for his family, by an improved method of
husbandry, without any increase on the average price of the
necessaries of life, teken for ten years previous to these
seasons of dearth. These, my lord, you and the Board
will feel to be subjects of the utmost national importance.
In a letter to the Bath society I affirmed that the saving of
seed cora by the general use of drilling would amount to
five million pounds sterling annually; and that, by the in-
crease of crop, and a judicious application of that crop, par-
ticularly of the straw, which when good is preferable to bad
or indifferent hay, an addition to the produce of the lands
now in cultivation might be made to amount, with the seed
corn saved, to fifteen million pounds sterling: and so care-
ful was I not to exceed the bounds of truth, that I am fully
persuaded my calculation is below what might be effected,
by one-half. May the laudable exertions of such patriotic
noblemen as yourself, and your intelligent predecessor lord
Somerville, be crowned with success! and may our agricul-
tural improvements and internal resources keep pace with
the increasing demands which the necessities of the times
must occasion !

A comparative Estimate between Grass and Aratle Lands.

Though I have demonstrated, by actual and extensive ex-
periments, the advantages resulting frem a judicious mode
of converting lands exhausted by tillage into meadow and
pasture, yet J do not allow that Jands under tillage for any
number of years must necessarily be in such an exhausted
state as to make this plan requisite: on the contrary, I am
fully persuaded that all lands capable of cultivation will, if
well tilled, fairly cropped and dressed, be in a progressive
State of improvement, and not enly produce a better rent to
the landlord, and pay twenty times as much to the produc-
tive labourers, but also yield a much greater profit to the oc-
eupier than the same number of acres in grass. Fine rich

M4 meadows

184 Estimate between Grass and Arable Lands.

meadows on the banks of rivers liable to be flooded, and such
as can be irrigated, no one would think of converting into
tillage; but all grass lands from ten to thirty shillings per
acre rent, I should wish to see tilled by judicious agricul-
turists. It is not necessary to give validity to my opinion
-by an exact detail of the produce of grass lands and arable
lands of the value to which I have confined my assertion.
If grass lands Jet for ten shillings per acre yield the gross
sum, on an average of years, of seventeen shillings, there
is so very little expense upon them the tenant could not
complain. If let tor twenty shillings, thirty shillmgs may
be the gross produce: if for thirty shillings, let forty-five
shillings be the average. As rates and taxes advance. with
the renis, probably this may be a fair estimate. In a na-
tional point of view, how cau these sums be equivalent to
those which must be produced from arable land, when every
agriculturist is convinced that the expense of labour only
on every acre of land well cultivated will amount to more
than three pounds by the time its produce is carted to mar-
ket? Whilst therefore these lands continue to pay the far-
mer for his additional trouble, skill, and capital, it is evident
the national produce must be increased. But some gentle-
mien apprehend such a preference to the plough would in-
crease the price of butchers meat to an alarming height.
To this Mr. Adam Smith would answer, that wheat will
ultimately regulate the price of all the necessaries of life. I
have full faith in the conclusion drawn by this able writer ;
but, as a farmer, I can obviate this objection without re-
sorting to his authority. Take this course of husbandry on
Jands worth thirty shillings per acre, turnips, or cabbages,
oats, clover, and wheat. The eighth part of an acre of
good turnips steamed, and with the liquor mixed with oat
straw cut, will keep a full grown beast in good order six
months. An acre of turnips, with the first crop of clover
hay, will fatten two bullocks in the same time. The wheat
- straw, with the addition of one-eighth of an acre of turnips,
will winter another beast ; and the second cut of clover an~
other. ‘Thus the produce of straw, turnips, and clover,
from the four acres, with the addition of one-fourth of
an acre of turnips, will keep three beasts six months,
and in the same time will fatten two bullocks of fifty
score each. The produce of four acres of grass land
let at thirty shillings per acre, would not send two fat bul-
locks to the market, and summer two. If I be correct in
my statement, which I trust I am, the advantage in favour
of the arable lands is more than the whole of the crops of
. wheat

Table of Crops. 185

wheat and oats. Gentlemen and farmers who have not
tried the effect of steaming the potatoe and turnip crops,
and stalling all their cattle, may suppose my calculations
erroneous ; but my own practice confirms the theory. The
quantity of rich manure raised will pay the additional la-
bour. I am aware that the estimate of productive labour
should not be restricted to the farm, and that the cattle or
the sheep, aiter they are disposed of by the grazier, find
employment for our manufacturers. But the advantages
derived from this do not more than counterbalance the sums
expended in manufacturing the produce of the arable lands
after it is carted to market by the grower. The wheat is
turned into various sorts of flour, starch, and hair powder;
the barley into malt, beer, and spirits. I have therefore
omitted the expense and profit on the produce both of grass
and arable lands after it 1s disposed of by the farmer. My
statements, from actual experiments, which constitute pro-
bably the most material part of this essay, your lordship
and the Board may depend upon. as correct. Should my
theory on other subjects, of the utmost national import-
ance, appear erroneous, it will be disregarded ; but, I trust,
with this indulgent conclusion, that the author’s wishes to
be of service to his country far outstrip his abilities; and
that, however light and superficial his arguments, when
weighed by the scale of superior knowledge and more ex-
tensive information, may appear, no one will doubt the pu-
rity of his intentions. [I have the honour to be, &c.
Tue AuTHOR,
To the Right Hon. Lord Carrington.

A Talle showing at one View a Course of Crops, adapted to
various Soils, for any Numler of Years.

Turnips Beans and Turnips o
r zg
Clay ; - Cab- i Oats 4 Gone } Wheat { Cabbapes
ages
‘Turnips f : Turnips or
Clayey Loam: { or ie } Oats Clover Wheat Cabbages
Turnips
Rich Loams and Po- | Barley Clover Wheat Beans
or Sandy tatoes
Loams Beans Barley Pease Wheat Ad infinitum
Turnips/ Barley Clover Wheat Potatoes
Peat Earth Turnips Barley Clover Wheat Potatoes
emt sub- } run ps Barley Clover Wheat Potatoes
Gravels Turnips Barley
Clover Clover
Light Lands Turnips Barley { and Rye ' { and Rye
Grass Grass

Days.

286

Table of Latour.

How employed.

L'wo men and four horses ploughing the first ficld in
—— lane; 3 men and 6 horses scarifying and harrow-
ing the further field; 2 men turning yp dung at Hill
Barn yard, at -—— ; 2 men cutting Hay and straw, look-
ing after oxen and cows at ditto; two mien and 1 boy
ditto at 3 9 women cutting potatoes at ——; 2 boys
keeping birds; 2 keeping cows; 1 boy pulling turnips;
1 man cutting coppice.

piel elie =
e ae bates |
Mr Pies. & FT
SF eet | i

XXXI. Proceedings of Learned Societies,

SOCIETY OF ARTS AND SCIENCES AT UTRECHT.

<=
=

ty, the
electric

h, proposed the fol

e question, to be answered before the 1st of Oc-

.
.

g new priz

1805 -
As the last observations and experiments on clectrici

Tars society, in its sitting of June the 15t

jowin
zober

Society of Arts and Sciences at Utrecht. 187

electric ec] and other fish of the like kind, as well as on the
Galvanic power, seem to indicate a great similarity and co-
incidence in their nature, and at the same time a percepti-
ble difference in their effects, the society requires a com-
parative view of these powers and effects, clearly explained
and founded on experiments.

The prize question proposed in the year 1800, in regard
to prevailing discases, to which no answer has been given,
is again proposed to be answered before the 1st of October
1805, with the usual prize:

«¢ What are the reasons that the diseases which prevail
at present among the inhabitants of Holland, at the differ-
ent seasons of the year, are not so simple. as in former
times? that is, do they arise from sources of an infectious,
bilious, or slimy kind, or from several other causes com-
bined ? ? and what is the best method of distinguishing with
certainty, at the commencement of these diseases, which of
the above causes has the ascendency? and what 1s the best
method of cure?”

The following question was proposed in the year 1802,
to be answered before the 1st of October 1804:

«‘ What are the causes that Holland, about the begin-
ning of the seventeenth century, was so much distinguish-
ed over other countries hy the great number of its w rriters,
original poets, and men of real Jearning ; and at the same time
produced i in the course of that century so many celebrated
painters, though the number of these has becn gradually
decreasing ever since? and what means of reviving the arts
and sciences may be digcovered by researches respecting
these causes ?”

Another question proposed 1 in the year 1799 was repeat-
ed in 1802, with a double prize, to be answered before the

Ist of October 1804; |

“¢ As the difference of opinions which prevail among
physicians respecting the so called pathologia humoralis,
has an influen¢e not only on physiological researches, but
on the state of the medical science, the socicty requires
that the following points may be determined by more .ac-
curate examination ;

© Ist, What peculiar diseases and faults in the j juices,
represented by Gaubius as vitia humorwn absoluta*, ac-
tually take place in the human body, and what are merely
supposed ? |
_ © 9d, Whether and how far such diseases arise from a

* Instit. Puch. Med. § 266 to § 382. :
peculiar

188 Scherer’s Journal.—<Aérostation.

peculiar and original degeneration in the juices? and whe-
ther these diseases of the juices arise wholly from a change
in the vital functions of the vessels and solids, or depend
chiefly on them? In case this question be answered in the
affirmative, Is the change of the juices which appears after
the use of medicines, to be deduced chiefly from the action
of these medicines on the juices and solids ?”’

The answers to these questions must be written in a
strange hand, and furnished with a motto. The name must
be written by the author himself in a sealed note. The
papers may be written in Dutch, German, but not in Ger-
man characters, English, French, or Latin, and must be
transmitted, post paid, to the first secretary, professor
Rossyn, or to the assistant secretary, Dr. Van Toulon, at
Utrecht. They must remain the property of the society,
and can be printed only by them.

XXXII. Intelligence and Miscelleneous Articles.
SCHERER’S JOURNAL.

P ROFESSOR SCHERER Of Berlin has been appointed profes-
sor at Dorpat, to which he has removed. » His Allgemeines
Journal der Chemie has therefore been closed with the
sixtieth number. It is to be succeeded, however, by the fol-
lowing work, dllgemeines Journal der Chemie, edited by
Hermbstadt, Klaproth, Richter, A. N. Scherer, and Gehlen.
The first number has been already published, and contains
Essays on the analysis and origin of meteoric stones and
metallic masses, by Klaproth, Vauquelin, and Wrede:
Essays on the prussic acid in vegetable substances, by Vau-
quelin and Bucholz ; chemical apparatus ; correspondence;
intelligence. M.Gehlen has undertaken to be principal
editor.
AEROSTATION.
Bologna, October 8th.
Yesterday the long announced aérial excursion of Count
Zambeccari took place, and in a manner entirely new. The
balloon, which was furnished with a lantern, and which
the count imagined he should be able to direct by means of
two wings applied to it, ascended in the night-time. Dr.
Grassett: and M. Andreoli accompanied the aérenaut in the
car. About one o’clock in the morning the balloon was
seen at Castel-Franco, about twelve Italian miles ee Bo-
ogna.

Aérostation. 189

logna. Its further fate is not yet known. Count Zam-
beccari’s intention was to make an aérial excursion from
Bologna to Milan.
Venice, October 14,
_ I write this to communicate to you the particulars of a
very singular and remarkable aérial voyage. Count Zam-
beccari of Bologna, Dr. Grassetti of Rome, and M. Pascal
Andreoli of Ancona, had some months ago prepared a
large and strong air balloon, which they filled in that
city on Friday the 7th. The filling, however, went on
very slowly, and was not completed till midnight. Count
Zambeccari and his companions were therefore desirous to
put off their ascent till the next day : but the impatience
and clamour of the populace obliged them to step into the
ear and suffer the balloon to ascend about three quarters of
an hour after twelve, though with a resolution of descend-'
ing as soon as they possibly could. The balloon rose with
the utmost rapidity, and soon reached such a height, that
Count Zambeccari and Dr. Grassetti, benumbed with cold
and seized with a nausea, fell into a state of insensibility
and deep sleep.
M. Andreoli, who alone retained the use of his senses,
was not able to determine the height by his barometer, as
the candle which he had in a lantern had gone out. About
half an hour after two in the morning the balloon began to
descend, and M. Andreoli soon observed distinctly the
waves of the Adriatic sea dashing against the coast of Ro-
magna. He therefore waked his companions, and endea-
voured to kindle the light by a phosphoric match, but with-
out success. At length, however, he obtained a.light by a
piece of flint and steel, and immediately after the balloon
fell into the Adriatic, and with such violence that the water
was dashed up to the height of several feet above them.
The aérial travellers, drenched with sea water and be-
numbed with cold, threw out in great consternation a bag
of sand, their instruments, and every thing they had with
them in the car. By these means the balloon rose again
rapidly : they then passed through three strata of clouds lying
over each other; in consequence of which their clothes
were covered with a thick rime; and on account of the
rarity of the air in which they now were’ when raised above
the clouds, they could scarcely hear each other speak. The
moon illuminated the atmosphere under them, and had a
blood-red colour. About three o’clock in the morning the
balloon again descended, but slowly, and a violent gust of
wind at south-west drove it across the Adriatic towards the
3 coast

‘

190 Aérostations

coast of Istria. The car several times téuched the waves j
aud the travellers were carried in this manner over the sur-
face of the sea for five hours, every moment in expectation
of being swallowed up by it. At eight o’clock on Satur-
day morning they were about twenty Italian miles from the
harbour of Veruda in Istria, when they were fortunately
picked up and saved from destruction by Anthony Bazol,
master of a large bark, who accidentally discovered them.
The balloon was abandoned to the wind, which droye it to~
wards the mountain of Opero, and in all probability it has
been conveyed to Dalmatias The aérial travellers, having
their feet and hands quite benumbed, arrived in the above
bark in the harbour of Pola, where they remained four days ta
recover from their fatigue. ‘This morning, at eight o’clock,
they arrived here, and gave the above aecount of their expe-
dition. Their journey from the coast of Romagna to Istria
was about twenty German miles. Had they not fallen in
with the before-mentioned master of a bark, they no doubt
nust have been buried in the waves: The aérial travellers
were received here with great hospitality; but they seem to
have no desire of undertaking another atrial excursion at

midnight. }
Genoa, October 24

According to further accounts from Venice, onc of the
aéronauts, whose misfortune we already have announced,
count Zambeccart, has altogether lost the use of his hands. It
appears that these philosophers ascended to a greater height
than any person ever did. Before Bazol observed them
and saved their lives, they were seen by a boatman of Lor-
rono in Istria; but as he thought he saw the devil in the air
surrounded by a globe of fire, he rowed from them as fast
as possible, and left them exposed to their fate.

Bologna, October 27.

Private letters from Venice represent the present state of
the unfortunate aéronaut, count Zambeccari, as very me-
lancholy. It has already been found necessary to amputate
his frozen fingers. His two companions, Dr. Grassetti
and M. Andreoli, have come off better: the former has:
arrived at this place. The other two are at Venice. The
journey they performed amounts to 30 German miles.
When they arrived at Pola, they were immediately blooded
by a surgeon, and their hands and fect were so much
swelled that it was found necessary to. make incisions in.
the skin.

Extract

Meteorology. ig}

Extract of a Letter from M. Garnerin.

Moscow, October 5.
My thirty-fifth ascent took place the day before yesterday
during calm weather, the wind being at north-west. f
ascended at five o’clock with my countryman, M. Aubert,
who suffered considerably in his ears by the rarefaction of
the air. Esaw for the first time an image of my balloon
formed in the clouds in very bright prismatic colours, We
descended at six o’clock at the country seat of prince Via-
semsky. Next morning I made another ascent at eight
o'clock. I passed through different regions of the air, and
rose to the height of more than 4000 toises, without expc-
riencing any other incopvenience than a cold of 4° Reau-
mur (41° Fabr.}. I galvanised myself, and observed flashes
of light. I discharged a musket twice: the report appeared
to be fainter than at the earth. TF should have continued
my voyage and observations, had it not been for the folly
of a hunter, who fired his piece loaded with shot at my bal-
Joon at the moment when I was hovering over a wood. [
was therefore obliged to descend, and at the same time to
be on my guard against the peasants, who, seeing me de-
scend from the clouds, frequently crossed themselves with
profound inclinations, and approached me and my balloon
slowly. A note written in the Russian language, which fF
threw down, enabled them to form some idea of the pro-
digy.. Count Solticoff advised me to this measure ; which
succeeded.
METEOROLOGY.

An uncommonly luminous meteor was seen on Sunday,
the 13th of November, about forty minutes past cight
o’clock at night. To some it appeared of an oval form,
and as followed by sparks which gave it somewhat the ap-
pearanee of having a tail. To others it seemed a wavy line
of light, which burst and divided itself into several small
balls of fire before it disappeared. It emitted a very vivid
light, by which the most minute objects could be distin-
guished, and moved with great velocity in a north-westerly

irection. Jt was seen not only all round the metropolis,
but, by the accounts that have reached us, over the greater
part of England, and nearly at the same instant of time ;
which proves that its height was considerable. It was suc-
ceeded, after an interval of a few seconds, by a peal of di-
stant thunder,

GEOGRAPHY,

192 Geography —Longevity.

GEOGRAPHY.

A Ietter from Madrid, dated October 10, states, that
orders have been issued from the secretary of state’s office
in regard to a general map of Spain, the plan of which was
formed some time ago, and actually begun, but interrupted
several times in consequence of various unforeseen circum-
stances. This plan, however, is now about to be carried into
execution, having been intrusted to the socicty of geographers
established some years ago under the ministry of the Prince
of Peace, and placed under the inspection of don Salvador de
Ximenes, director of the observatory of Madrid, to whom
the society is particularly indebted for its organization and
progress. Two of its members, captains Ybarra and Sa-
rasa, have already received their instructions; one to su-
perintend the geometrical and the other the astronomical
operations, by which the position of each place will be ac-
curately laid down. A certain number of pupils distributed
in different provinces, and always stationed in such a man-
ner as to be under the inspection of the chiefs, will assist
them in their labour ; and eminent mineralogists and bota-
nists have been appointed to collect information in regard
to the productions of the different provinces, their popula-
tion, the nature of the soil, &c. By these means the Spa-
nish government will obtain a complete statistical account
of its wide dominions, and be better enabled to introduce
such improvements as the present state of the country may
require. i

LONGEVITY.

The following extraordinary instance of Jongevity is given
m a late German journal :—* There is now living near Po-
Josk, on the frontiers of Livonia, a Russian who served
under Gustavus Adolphus, king of Sweden. He was pre-
sent at the battle of Pultawa in 1709, at which time he was
eighty-six years of age. At the age of nimety-three he en-
tered into the married state, and had children. ‘The family
of this patriarch consists of 186 individuals, who reside to-
gether in a village which comprehends ten houses. ‘The
oldest of his grandchildren is 102; the age of the next ts
not less than a century. This old man still enjoys a perfect
state of health, though now 180.”

- Erravrum.—In our last Number, page 95, last line of Note, for erhe
read e/her. 14"

[ 193 ]

XXXIIT. On Gems. By W.H. Pepys jun. Esq. P. R. 0.
Member of the -Askesian Society. Read in the Session
1802-3 *.

Tins class of badies has engaged the attention of all ranks
of society from the earliest ages : their beauty, and property
of decomposing light, producing the variegated colours of
the prism and the rainbow, will always procure them a place
in the most splendid and sumptuous displays of human
magnificence.

To the philosopher they open a wide and extended field
in his inquiries into the secret works of nature; and the
cabinet of the mineralogist becomes more interesting and
enlivened by their presence.

We find the greater part of them were used in the costume
of the priests of the temple :—* And they set in it (the breast-
plate of the priest) four rows of stones: the first was a
sardius, a topaz, and a carbuncle,—this was the first row ;
and the second row an emerald, a sapphire, and a diamond;
and the third row a ligure, an agate, and an amethyst ; and
the fourth row “a beryl, an onyx, and a jasper; and they
were inclosed in ouches (or toils) of gold in their in-
closings.”

Those which are most esteemed, and reckoned the most
valuable, with the moderns, are : ;

1. The diamond. 6. The hyacinth.
2. The ruby. 7. The beryl.

3. The sapphire. 8. The amethyst.
4. The emerald. g. The garnet.

5. The topaz. 10. The chrysolite.

1. The diamond, formerly classed with the siliceous ge-
nus, is now acknowledged to belong to the inflammable or
carbonaceous: it has the greatest degree of transparency,
and is the most beautiful and most brilliant of all the pre-
cious stones. It produces only single refraction, but its
refractive powers are stronger than that of any other body ;
it separates the colours better; and this is the cause why it
sparkles with so much lustre, especially in the light of the
sun. An artificial gem of glass does not reflect the light
from its hinder surface until that surface is inclined in an
angle of 41 degrees, while the property of the diamond is
such as to occasion all the light to be reflected, which falls

* Copied, by permission, from the Records of the Socicty.

Von. XVIT. No. 67. N on
December 1803.

194 On- Gems.

on any of its interior surfaces at a greater angle of inci-
dence than 241 degrees. The diamond, therefore, will not
only throw back all the light which an artilicial gem would
reflect, but likewise one-half as much more, which, falling
between the angles of 41 degrees and 241, would have been
suffered to pass through by the false gem.

There are two kinds of the diamond, the Oriental and the
Brasilian, which differ only in the form of their crystalliza-
tion.

The Oriental diamond crystallizes in octaédra, composed
of two pyramids having four equilateral triangular faces, a
little convex, united by their bases. ‘This form is some-
times modified into a figure of twenty-four faces, and some-
times even of forty-eight, all triangular and somewhat con-
vex. The specific gravity of the Oriental diamond is 3°5212.

The Brasilian diamond crystallizes in dodecaédra, the
twelve faces of which are rhombs a little convex. The
specific gravity of this stone is 3°4444,

The Oriental diamonds are found in the kingdoms of Gol-
conda, Visapour, Bengal, and the island of Borneo, There
are four mines, or rather two mines and two rivers, whence
diamonds are drawn. ‘The mines are: Ist, That of Raol-
conda, in the province of Carnatica, five leagues from Gol-
conda and eight or nine from Visapour: it has been disco-
wered about 300 years. 2d, That of Gani or Colour, lying
eastward of Golconda: it was discovered about 200 years
ago by a peasant, who digging in the ground found a na-
tural fragment weighing 25 carats. 3d, That of Somelpour,
or rather of Gaoul, that being the name of the river in the
sand of which these stones are found: this 1s the most an-
tient of them all. Lastly, The fourth mine, or rather the
second river, is that of Succudan, in the tsland of Borneo.

The diamonds from Raolconda are found in a rocky soil,

throngh which run several small veins of half an inch, or
sometimes an inch, broad, out of which the miners, with a
hooked instrument, draw the sand in which the diamonds
are. When a sufficient quantity of the earth is obtained,
they wash it several times to separate the stones therefrom.
These men work quite naked, except a cloth drawn round
the middle; and besides this precaution, they have hkewise
inspectors to prevent their concealing of stones, which they
frequently do by swallowing them.

In the mine of Gani, or Colour, was found the famous
diamond of Aureng Zeb, the great mogul, which, before
it was cut, weighed 793 carats. The miners dig 12 or 14
fect deep, and till such time ag they find water, which serves

] them

‘
||
i

On Gems. 195

them to wash the earth obtained: when well washed and
dried, they. sift it in a kind of open sieve, and search it well
for the diamonds it may contain. These people work also
naked, with inspectors over them.

The diamonds from the river Gaoul and Succudan are
obtained by damming or stopping a part of the rivers,
which they empty of their water; then taking up the sand,
they sift it and search it for the diamonds.

The province of Brasil, which produces diamonds, is si-
tuated inland between 221 and 16 degrees of south latitude :
its circumference is near 670 leagues. This province is di-
vided into four districts. The diamonds are found chiefly
in the Jast, called Sero Dosrio, or Cold Mountain. The
whole of this province is rich in the ores of iron, antimony,
zinc, tin, silver, and gold.

The mountains are the true matrix of the diamond; but
as the work in the beds of rivers and on their banks 1s less
tedious, can be conducted on a larger scale, and affords
larger diamonds, they abandoned the mountain, and formed
great establishments ; in the river of Toucanbirnen, which
flows through the valley, and is near ninety leagues in
length. It was found, on examination and digging, that
the whole surface of the ground immediately beneath the
vegetable stratum contained more or less of diamonds dis-
seminated and attached to a matrix, ferruginous and com-
pact in various degrees, but never in veins.

These works are not carried on by the Portuguese go-
vernment, but are farmed to certain individuals, who are
bound by contract not to employ above a stipulated number
of slaves upon these districts, as before this condition the
quantity of diamonds brought into the market considerably
lowered their value.

In the choice of roygh diamonds great care should be
taken in regard to their colour, their being free from ex-
traneous matter, and their shape.

The most perfect are crystalline, and resembling a drop
of clear spring water, in the middle of which you will per-
ceive a strong light playing with a great deal of spirit. If
the coat be smooth and bright, with a little tincture of green
in it, it is not the worse, and seldom proves bad: but if
there be a mixture of yellow with green, then beware of it ;
it is a soft greasy stone, and will prove bad.

If a stone has a rough coat that you can hardly see
through it, and the coat be white, and look as if it was
rough by art, and clear of flaws or veins, and no blemish

N 2 - cast

196 On Gems.

east in the body of the stone, which may be discovered by
holding it against the light, the stone will prove good.

It often happens that a stone shall appear of a reddish
hue on the outward coat, not unlike the colour of rusty
iron, yet by looking through it against the hght you may
observe the heart of the stone to be white; and if there be
any black spots, or flaws, or veins in it, which by a true eye
may be discovered, although the coat of the stone be opake,
such stones are generally good.

If a diamond appear of a greenish bright coat resembling
a piece of green vlass mclining to black, it generally proves
hard, and seldom bad: such stones have been known to be
of the first water: but if any tincture of yellow seems to
run with it, you may depend upon its being a bad stone.

All stones of a milky coat, whether the coat be bright or
dull, if ever so little inclining to the blucish cast, are natu-
rally soft, and in danger of being flawed in ‘the cutting ;
and though they should have the good fortune to escape,
yet they will prove dead and milky.

All diamonds of a cinnamon-coloured coat are very du-
bious ; but if of a bright, mixt with a little green, then they
are certainly bad, and are accounted amongst the worst of
colours.

The greatest care must be taken to avoid beamy stones ;
and this requires gieater skill and practice than many jew-
ellers are equal to. By beamy stones are meant such as look
fair to the eye, and yet are so full of veins to the centre that
no art or labour can polish them; they run through several
parts of the stone, and sometimes through all: when they
appear on the outside they show themselves like protuberant
excrescences, from whence run innumerable small veins
obliquely crossing each other and shooting into the body
of the stone: the stone itself will appear a very bright coat,
and shining, and the veins looking like a very small po-
lished steel needle ; sometimes the knot of the veins will
be in the centre, and fibres shoot outward, and the small
ends terminate in the coat of the diamond: stones having
these properties are difficultly cut, and will never take a good
polish.

There are diamonds of almost all colours: some incline
to rose colour, others to green, blue, brown, and black.
Mr. Dutens saw a black diamond at Vienna im the collec-
tion of the prince of Lichtenstein.

The diamond becomes phosphoric by exposure to the solar
rays, or by heating it red hot in a crucible on the fire. It

3S

On Genrs. ' 107

as electric when rubbed, and affects the electrometer with
the negative power.

It was always supposed to be the most refractory and in-
destructible in the fire, till the experiments of d’Arcet and
Macquer proved the contrary: but they supposed it to be
volatilized; they had no idea of its combustion. D’Arcet
and Maequer’s experiments were made in consequence of
an observation of Boyle’s, that the diamond, when exposed
to the action of a violent fire, emitted acrid vapours.

The emperor Francis the First caused diamonds and ru-
bies to be exposed in crucibles to a reverberatory fire for
24 hours: the diamonds disappeared, but the rubies re-
mained unaltered. These experiments he had again repeated
at an expense of six thousand florins.

The grand duke of Tuscany had a series of experiments
made with a large mirror and the concentrated rays from
the sun upon the diamond, in which it was destroyed. It
required a short period for its being completely volatilized,
as it was then called.

Macquer seems latterly to have had another opinion, when
he says, he observed the diamond dilated and swelled up,
and that a blue flame was observable on its surface.

Lavoisier and Cadet proved the combustion of the dia-
mond, and that it ceased as soon as the oxygen was de-
stroyed; and that the stone only burnt in proportion to
the oxygen present, like all other combustible substances.
Lavoisier also observed that the gas produced during the
combustion precipitated lime water, which effervesced upon
the addition of an acid.

Sir Isaac Newton, from its great power of refracting the
light, conjectured it was a combustible body: his words
are, © it is probably an unctuous body coagulated.”

Tennant exposed two grains and a half of smali diamonds
and a quarter of an ounce of nitre (nitrate of potash) in a
gold tube, connected with a pneumatic apparatus, in a red
heat for an hour and a half: the gas that was given out was
from the decomposition of the nitre, with scarcely a trace of
carbonic acid; but the residuum, upon careful examination,
had been partly converted into carbonate of potash; the
diamonds had completely disappeared. Upon analysing the
residuum, as much carbonic acid gas was obtained as would
occupy the space of 10°1 ounces of water. Upon repeating
this experiment with another weight of diamonds, he found
the proportions as 103 of carbonic acid to two grains and
a half of diamond: two grains and a half of charcoal would
have given ten of carbonic acid.

N 3 That

198 On Gems.

That oxygen gas assists materially in the combustion of
the diamond, has been proved by some experiments made
by the London Philosophical Society *. These experiments
were suggested by Mr. Francillon, who supplied the stones
for that purpose from his cabinet.

A diamond weighing }4ths of a carat was exposed to the
action of a stream of oxygen gas upon ignited charcoal: in
one minute and fifty seconds it was found to have lost 11ths
of its original weight; it had also Jost its figure, transpa-
rency, and polish. The unconsumed portion was cut atter
the experiment, and exhibited exactly the ‘same Justre as
before.

Several others were tried, with the same results: one,
which was accidentally thrown from the charcoal, was seen
distinctly burning during its passage through the air; the
flame was of a blueish pearl colour, and nearly 3-4ths of an
inch in length.

Guyton has proved, by a series of experiments on the
diamond in oxygen gas, exposed to the action of the con-
centrated rays from the sun, that this substance is one of
the purest forms of carbon; and that the other known
classes of carbonaceous bodies are in intermediate states of
oxygenation, which to a certain degree increases their com-
bustibility, and power of decomposing the air.

The difference between the degrees of temperature neces-
sary for the combustion of the diamond and charcoal are
as 188 to 2765 of a Wedgwood’s scale.

Charcoal set on fire in oxygen gas does itself maintain
the temperature necessary for its combustion ; but the com-
bustion of the diamond ceases as soon as it is no Jonger
maintained by the heat of the furnace, or the concentration
of the solar rays.

The diamond requires for its complete combustion a
much greater quantity of oxygen than charcoal does, and
likewise produces more carbonic acid; for one part of char-
coal absorbs 2°527 of oxygen, and produces 3°575 of car-
bonic acid. But one part of the diamond absorbs somewhat
more than four of oxygen, and really produces five of car-
bonic acid,

The diamond is the pure state of carbon. Plumbago is
its first state of oxidation; charcoal its second; gaseous
oxide of carbon its third; and carbonic acid its completion.

Guyton, to prove the carbonaceous property of the dia-
mond, conyerted soft iron into steel by cementation with

* See Philosophical Magazine, vol. viii. ;
Ita

On Gems. 198

it. Mushet converted the iron into the same state without
the diamond being present. Mackenzie supports Guyton,
and denies that this could have been done without the pre-
sence of some carbonaceous matter in the crucibles. Mushet
says that carbon penetrates the crucibles at these elevated
temperatures: and thus the experiment rests.

The substance of diamonds is Jamellated, consisting of
very thin plates like those of tale, but extremely hard and
intimately united, whose direction lapidarics must find out,
not only to cleave the ill-shaped stones, but to cut and shape
them properly. This last operation is performed by rub-
bing one diamond with another till it has acquired the
shape; it is afterwards polished on a horizontal wheel of
steel, employing the same powder that falls from their rub-
bings with common olive oil.

Jefiries calculates the mean value of diamonds by multi-
plying the square of their weight in carats by two pounds
sterling, when the diamond is rough or uncut; but if it is
already cut, the simple square of their weight must be mul-
tiphed by eight pounds sterling: this great difference in
price proceeds from the great loss which a diamond suffers
in being cut. Fits

The two first of the following diamonds are uncut, the
other six are cut diamonds:

Ist. The greatest diamond that ever was known in the
world is one belonging to the king of Portugal, which was
found in Brasil; it is still uncut: it was of a larger size,
but a piece was cleaved or broken off by the ignorant coun-
tryman who chanced to find this great gem, and tried its
hardness by the stroke of a large hammer on an anvil.

This prodigious diamond weighs 1680 carats: if we em-
ploy to value it the general rule above mentioned, this great
gem must be worth at least 5,644,800 pounds sterling,
which are the product of 16802 by two pounds.

ad. The diamond which adorns the imperial sceptre of
Russia, under the eagle at the top of it, weighs 779 carats,
and is worth at least 4,854,728 pounds sterling, although
it hardly cost 135,417 guineas. - This diamond was one of
the eyes of a Malabarian idol, named Scheringham. A
French grenadier, who had deserted from the Indian ser-
vice, contrived so well as to become one of the priests of
that idol, from which he had the opportunity to steal its
eye: he ran away to the English at Tricinapalli, and
thence to Madras. A ship captain bought it of him for
20,000 rupees ; afterward a Jew gave 18,000 pounds ster-
ling for it: at last a Greek merchant, named Gregory Suf-

N4 tras,

200 On Gems.

fras, offered it to sale at Amsterdam, and the late prince
Orloff bought it-pf him for the empress of Russia.

3d. The diamond of the great mogul is cut in rose,
weigh 279.9. carats, and is worth 380,000 guineas.

4th. Another of the king of Portugal, which is cut,
weighs 215 carats, is extremely fine, and worth at least
369,800 guineas.

5th. The diamond of the grand duke of Tuscany, now
of the emperor of Germany, weighs 1394 carats, and is
valued at 109,520 guineas.

6th. The diamond of the late king of France, called the
Pitt or Regent, weighs 1363 carats: this gem is worth
208,333 guineas. It was sold by governor Pitt to the
duke of Orleans for 135,000 pounds.

7th. The other diamond of the same monarch called the
Grand Sancis, weighs 55 carats *, and cost 25,000 guineas.

8th. The diamond called the Pigot weighs 47% carats,
valued at 20,000 guineas; parted with by the Pigot family
by lottery in 1800.

The Ruby.

The ruby is a precious stone of a fine full red colour,
electrical by friction, giving fire with steel ; the most pon-
derous and the hardest of the precious stones after the dia-
mond: it crystallizes in long hexaédral pyramids applied
base to base without an intermediate prism.

Its specific gravity is from 3°18 to 4°283. It is not vi-
trified in the fire without addition, and even resists the ac-
tion of the burning mirror.. Flame urged by oxygen-gas
easily fuses it. . It does not lose its colour at the degree of
heat which is sufficient to melt iron. The borate of soda
and microcosmic sajt fuse it, and give a transparent glass
of a pale green colour: with the mmeral or vegetable alkali
the glass 1s opake, and of various colours.

A perfect ruby above 34 carats weight is more valuable
than a diamond equally heavy. If it weighs one carat, it is
worth 10 guineas; two carats, 40 guineas; three carats,
150 guineas ; if six carats, above 1000 guineas.

There are 108 rubies in the throne of the great mogul,
which from their weight are called carbuncles; they are
from 100 to 2090 carats each.

The varieties of the ruby are called the oriental ruby, the
spinelle ruby, the balass ruby, and the rubicelle. The first
is of a deep red colour; the second of a bright corn poppy-

* Chaptal says 106 carats.
flower

On Gers. 201

flower colour; the third a pale red inclining to violet; and
the fourth of a reddish yellow colour.
Vauquelin’s analysis of the onental ruby gives

Alumine - Sita 86°00
Magnesia saa - - 8°50
Chromic acid - = 5:25

99°75

The Sapphire.

The sapphire is a precious stone of a transparent blue co~
Jour, and is the hardest.next the ruby: the oriental sap-
phire and that of Puy have the form of two very long hexa-
édral pyramids, joined, and opposed base to base without
the interposition of a prism. Sapphires have been found
of a rhomboidal form.

The specific gravity of the sapphire of Puy is in propor-

tion to water as 40°769 to 10:000; that of the white sap-
phire is as 39°911; and the Brasilian as 31-307.
- The sapphires from d’Expaily have a green tinge, and
ehange in the fire in the same manner as those of the Bra-
sils; whereas the oriental sapphire is not altered in our fur-
naces. The action of oxygen gas upon this stone gives a
perfect white opake globule.

A good sapphire of ten carats is valued at 50 guineas; if
it weigh twenty carats, its value is 200 guineas ; but under
ten carats it may be valued by multiplying the carat at ten
shillings and sixpence into the square of its weight.
| They are found, as well as rubics, in the East Indies,
Brasil, Hungary, Silesia, Bohemia, and also in Siberia.

The analysis by Bergman and by Klaproth:

Bergman. Klaproth.

Silex = - 35 Alumine - = 98°50
Alumine - 58 Oxide of iron - 1:00
Lime 5 Lime - = <= 50
Iron + - @2

—_—— 100

100 .

The Emerald.

The emerald is a gem of a fine, full, transparent green
colour, electrical by friction. It is next in hardness after
the topaz. The Peruvian emerald crystallizes in hexaédral
prisms truncated, flat at each extremity. Crystals pido :

ya

502 On Gems.

rald are frequently found inserted in the gangues of quartz,
and even of fluor.

Its specific gravity compared with that of water is as
97°755 to 10°000.

The emeralds which come from America are called occi-
dental: Peru and the Brasils afford the most beautiful.

The emerald melted in the furnace of Pott: it was spee-
dily fused by the mirror: oxygen gas fuses it in a white
milky bubble tinged with green.

The emerald analysed by Vauquelin afforded

Silex - - - 64°60
Alumine - - 14:00
Glucine - - 13°00
Chrome - ~ 3°50
Lime - - - 2°56

94°66

The Topaz.

The topaz is a precious stone of a fine golden yellow co-
lour. The oriental topaz takes the octaédral form; the Bra-
silian crystallizes in rhomboidal tetraédral prisms, grooved
longitudinally: they are terminated by two tetraédral py-
ramids with smooth triangular faces. The Saxon —
exhibits Jong suboctaédral prisms, terminated by hexaédral
pyramids more or less terminated at their base.

The specific gravity of the oriental 1s as 40°106 to 10°000 ;
that of the Brasilian 35°365 to 10°000.

The topaz is not fused in the porcelain furnace ; but both
the Oriental and the Brasilian are fused, and lose their colour
tor a white opake mass, by oxgen gas.

The topaz analysed by Vauquelin gave

Silex - - -
Alumine > “ge Ol

The Hyacinth.

The hyacinth is a stone of a fine reddish yellow colour;
it is usually crystallized in the form of a rectangular tetra~-
édral prism, terminated by two quadrangular pyramids with
thombic faces.

Its specific grayity compared with water is as 36°873 to
10°000.

It

On Gems. 203

Tt loses its colour in the fire: with oxygen gas it is fused
into a globule resembling bottle glass.

Hyacinths are found in Poland, in Bohemia, in Saxony,
Welay, &c.

Modern analysis has classed the jargon of Ceylon with
this stone, the analysis of which is given by Klaproth and
Vauquelin:

Hyacinth. - Jargon of Ceylon.
Zirconia - - 68:0 Zirconia - 70:0
Silex - - - 31:5 Silex - - 25:0

Nickel and iron = 0°5 Oxide of iron = 0°5

100°0 95°35

es

The Beryl, or Aqua Marina,

Is a precious stone of a blueish grecn colour: the Saxon
as well as the Siberian crystallize in hexaédral, striated,
truncated prisms of a lamellated texture. This stone is
also found at Baltimore, in America.

Its specific gravity is 35°489 for the oriental, 27-297 for
the occidental.

It yielded, upon analysis by Vauquelin,

Silex ~ - 69
Alumine ~ ~ 13
Glucine - - - 16
Oxide of iron <a 1°5
99°5

The violet-coloured amethyst, the crimson garnet, the pale
blue water sapphire, the girasol, the jacinth, and the chry-
solite, do not offer us any thing new, considered in a che-
mical point of view: they are also stones of an inferior va~
lue to those we have spoken of, which by their lustre and

superior hardness have obtained the first place in the cabinet
of the virtuoso,

XXXIV. Of

» Dges..o}

XXXIV. Of the general Relation between the Specific Gra-
vities and the Strengths and Values of Spirituous Liquors,
and the Circumstances by which the former are influenced.

[Continued from vol. xvi. p. 312.]
Of Mr. Gilpin’s Tables.

§ 28. it appears that the importance of the subject of the
present essay has long since been universally acknowledged,
and that it has accordingly at various periods attracted the
attention of the legislature. Shortly after the passing the act
27 Geo. IIf. c. 31, already mentioned in § 18, an applica-
tion was made by government to sir Joseph Banks, bart.,
president of the Royal Society, to put the matter m such a
train of investigation as might lead to the ascertaiming of
the actual relative values of spirituous liquors, and the con-
sequent just appreciation of the duties to be paid in respect
of them. Sir Charles Blagden, who was at that time the
secretary of that learned body, was accordingly requested
io assist in this business, and draw up a report of the results
of such experiments as should have been made with regard
to the subject, and which Dr. Dollfuss, a Swiss gentleman,
at that time m London, was engaged to perform. He ac-
cordingly tried a vast number of experiments for ascertain-
ing the effects of combination and temperature under all
possible circumstances on the specific gravities of spirituous
liquors. The genera] course of experiments was made with
malt spirit; but he tried also several comparative ones with
such as had been rectified from rum and brandy, and found
no other difference than such as might be fairly ascribed to
unavoidable errors. a
Upon examining the whole series of Dr. Dolfuss’s results,
it was afterwards perceived, however, that though the num-
bers as tabulated agreed tolerably well upon the whole, yet
there was in some places found a sufficient degree of irre-
gularity in the progression of the first differences to render
rt adviseable to repeat several of the experiments ; and Dr.
Dolliuss leaving England about that time, the business of
this repetition was entrusted to Mr. Gilpin, clerk of the
Royal Society. This gentleman had already participated in
the work, by assisting Dr. Dollfuss in the former experi-
ments, particularly in the very nice operation of weighing
the mixtures ; his skill, accuracy, and patience, being well
known to the society in general. Mr. Gilpin became in-
terested in the business; one experiment led on ta ae
anc

On the Strengths and Values of Spirituous Liquors. 205

and he was at length induced to go through the whole series
anew. Of the results of these experiments sir Charles
Blagzden laid a report before the society, which was read
the 22d of April 1790; and afterwards 2 supplementary re-
port, which was read the 28th of June 1792. To state
every thing of importance which they contain, they must
be copied verbatim: we shall however endeavour, with as
much perspicuity as we can, to trace the outlines of their
contents.

The spirit at first employed by Mr. Gilpin was furnished
him by Dr. Dollfuss, under whose inspection it had been
rectified from rum supplied by government : its specific gra-
vity at 60° was 825°14. That which he afterwards used was
distilled for the purpose by Mr. Schmeisser, who brought
some of it to the specific gravity of 817; and its agreement
with the former with respect to its specific gravity, when
diluted and subjected to change of temperature, was tried
before it was employed in tlre experiments. The spirit,
however, which they thought proper to assume as what ap-
peared to them a convenient standard of value, was that
which has the specific gravity of 825 at 60°; and the
stronger alcohol which they used was therefore previously
diluted with distilled water to that degree of strength.

The mixtures were made by weight, as the only accurate
method of fixing the proportions. It was conceived that,
in fluids of such very unequal expansions by heat as watér
‘and alcohol, if measures had been employed, it would not
only have been necessary to make a different mixture for
every different degree of heat, but the proportions of the
masses would have been sensibly irregular; and the object in
view was to determine the real quantity of spirit in any given
mixture, abstracting the consideration of its temperature.
Another principal consideration was, that with a very nice
balance, such as was employed on this occasion, quantities
would be determined to much greater exactness by weight
than by any practicable way of measurement: the propor-
tions were therefore always taken by weight. A phial being
provided of such a size as that it should be nearly filled with
the mixture, was made perfectly clean and dry; and, being
counterpoised, as much of the pure spirit or of distilled
water as appeared necessary was poured into it. The weight
of this spirit or water was then ascertained, and the water
or spirit required to make a mixture of the intended pro-
portions was calculated. This quantity of fluid was then
added with all the necessary care, the last portions bein

4 put

306 Relation between the Specific Gravities and

put in by means of a well known instrument, which is
composed of a small dish ternunating in a tube drawn to
a fine point: the top of the dish being covered with the
thumb, the liquor in it is prevented trom running out
through the tube by the pressure of the atmosphere, but
instantly begins to issue by drops, or in a very small stream,
upon raising the thumb. The liquor lastly added being thus
introduced into the phial till it exactly counterpoised the
weight, which, having been previously computed, was put
into the opposite scale, the phial was shaken, and then well
stopped with its glass stopple, over which leather was tied
very tight to prevent evaporation.

In this manner 100 parts by weight of spirit of the last-
mentioned specific gravity of 825 at 60° being first put into
the bottle, five parts by weight of distilled water were added,
so as to form a compound in these proportions. In the
mext experiment 10 parts of water were added to 100 by
weight of the spirit; in the aext, 15; in the next, 20; and
so on, increasing the weight of water by five parts in each,
until 100 parts, or an equal weight of water, were added to
the spirit. One hundred parts of water by weight were
then taken as the invariable quantity, and 5, 10, 15, 20,
&c., parts of the same spirit successively added, so as to
produce 20 more weaker compounds; the last, or 100 to
100, being equal in strength to the last of the former series.
No mixture was used till it had remained in the phial at
Jeast a month, for the full penetration to have taken place ;
and it was always well shaken before it was poured out to
have its specific gravity tried. ‘

The mode of performing this operation which these gen-
tlemen preferred on this occasion, was that of actually
weighing the liquor in a vessel which was capable of being
at all times equally filled to a great devree of exactness, hav-
ing first ascertained its weight when so filled with distilled
water. It was a hollow. glass ball, terminating in a neck,
which was formed of a portion of barometer tube 1-4th
of an inch in diameter, and 11 inch Jong. That used by
Dr. Dollfuss contained, when filled to a mark cut reund
the neck with a diamond for that purpose, 5300 grains of
distilled water; but the one afterwards preferred by Mr.
Gilpin was sinaller, and contained when so filled only 2965
grains of the same fluid at Go?. The bottle itself weighed
916 grains, and with its silver cap 936. Its bulb was about
2-8 inches in diameter ; and Mr. Gilpin found, that on fill-
ing it several times successively to the same mark at equal

tempcratures,

the Strengths and Values of Spirituous Liquors. 207

temperatures, and with every possible precaution, the quan-
tities of fluid by weight did uot appear to differ more than
about +,1,,th of the whole.

The bottle being filled nearly to the mark, the liquor was
then brought to the required temperature, as ascertained by
a thermometer made for the purpose by the late Mr. Rams-
den, and graduated to fifths of a degree of Fabrenheit’s
scale, which was introduced through the neck into the li-
quor, its bulb being only +22 of an inch in diameter. The
neck was then filled quite up to the mark with more of the
same liquor at the same degree of heat, and the whole
weighed in that state. This was performed at every five
degrees of temperature. The first temperature at which
the liquor was weighed was 60°; it was then gradually
cooled down to 55°, 50, 45, &c., and, lastly, to 30°; after
which its temperature was in like manner raised to 100°, it
being again weighed at every five degrees ; and, lastly, it was
again cooled down to 60°, at which temperature it was
weighed a third time, and the process terminated with re-
spect to that compound,

The balance was that of the society, made by the late
Mr. Ramsden, and of which some account may be found
in the 33d volume of the Jowrnal de Physique. It was so
exceedingly sensible, that the fiftieth part of a grain consi-
derably deranged the position of the beam when loaded with
the scales and their contents in these operations.

From this course of experiments Mr. Gilpin afterwards
computed a voluminous set of tables, which are published
in the Philosophical Transactions for the year 1794. They
occupy 100 quarto pages closely printed ; each page being
divided in the middle, so as to be virtually extended to twice
its length.

They are calculated for every degree of temperature, from
30° to 80° of Fahrenheit’s thermometer, the results at each
of which occupy two of these pages, the degree of heut
standing at the head of each.

The lett hand page contains those belonging to all com-
pounds of 100 parts by weight of alcohol of the specific
gravity of 825 at 60°, with every integral proportion of water
also by weight from 0 to 100; and the right hand page those
belonging to all compounds of 100 parts by weight of wa-
ter, with every proportion of such alcohol also by weight
from 0 to 100. These mixtures by weight constitute Co-
Jumn I in each table, which is entitled accordingly, on the
left hand page, ‘ Spirit and Water by Weight,” and on
the right hand page, “* Water and Spirit by Weight.”

Column

208 — Relation between the Specific Gravities and

Column II, of all the tables, gives the specific gravities
of the corresponding mixtures of” spirit and water in Co-
lumn J, compared with that of distilled water at 60°.

In Column III, 100 parts by measure of pure spirit, at
the temperature marked on the top of every separate table,
is assumed as the constant standard number to which the
respective quantities of water by measure at the same tem-
perature are to be proportioned in the next column. It is
entitled ** Spirit by Measure.”

Column IV therefore, which is entitled “ Water by
Measure,” contains the proportion of water to 100 mea-
sures of spirit, answering to the proportions by werght in
the same horizontal line in Column I.

Column V shows the number of parts which the quan-
tities of spirit and water contained in the third and fourth
columns would measure when the mixture has been com-
pleted; that is, the bulk of the whole compound after the
concentration or mutual penetration has fully taken place.
It is entitled “ Bulk of Mixture.”

Column VI gives the effect of that concentration, or
how much smaller the volume of the whole mixture is than
it would be if there was no such principle as the mutual
penetration: It is entitled * Diminution of Bulk.”

Column VII shows the quantity of pure spirit by mea-
sure, at the temperature in the table, contained in 100 mea-
sures of the mixture laid down in the fifth column; and is
entitled “* Quantity of Spirit per Cent.”

And, lastly, Column VIII, entitled Decimal Multi+
pliers,’ gives the proportion by measure of the beforemen-
tioned spirit, when reduced to 60° of heat, which is con-
tained in any measure of each compound, if measured at
the temperature expressed at the head of the table, pursuant
to the idea suggested in sir Charles Blagden’s report, that
*< the simplest and most equitable method of levying the
duty on spirituous liquors would be to consider rectified
spirit as the true and only exciseable matter.”

The whole of these tables, therefore, contain, as appears
by the foregoing account of them, no less than 80,000 de-
ductions from experiment or calculation. It is difficult to
speak with sufhcient praise of this work: those only who
have been in the habit of conducting similar operations are
at all capable of appreciating labours like these.

§ 29. There seems to be no doubt of the authenticity of
the experiments on which these tables are founded. They
were repeated again and again with extreme care, with the
most exquisite instruments, and with great knowledge “ “a

the

the Strengths and Values of Spirituous Liquors: 209

the subject ; and, if it be not presumptuous in us to make

the assertion, they stand strongly. confirmed by our own:
experiments with respect to these matters.

~ It appears, therefore, at first. sight, rather extraordinary

that a work which does so. much. honour to. the country

should not be more generally known and-understood than

this is; and is, perhaps, only to be.attributed to two‘causes.

Firstly, The arrangement of .the tables is confessedly in-
convenient: the entering. them with the quantities of spirit
and water by weight, (a proportion which is in no’case the
primary result of an experiment for thé examination of a
spirituous compound, and can only be deduced from calcu-
lation founded on its specific gravity and temperature), ren-
ders them ill adapted to general purposes. nln

Secondly, They are calculated on the supposition that
the recommendation of sir Charles Blagden, to consider
alcohol of the specific.gravity of 825-at 60° as the true and
only exciseable matter, would be adopted by the govern-
ment; and though they therefore give the equivalent quan-
tities of spirit of this kind to the respective quantities of
the several compounds which are there mentioned, yet
they do not give the equivalent quantities of the present
proof. :

Though it is with diffiidence that the authors of this tract
venture to differ from those gentlemen who have already
displayed in the above work so intimate an acquaintance
with the subject, yet they cannot help saying, that, from
the opportunities which they have had of observing the

ractical course of this business, they have always rather
boc of opinion that it would be more convenient to fix on
some strength which most frequently occurs in commerce
as the standard for that of spirituous liquors in general, than
one which considerably differs from that of those usually
found in the market. Jt is a new race of men who can
alone derive advantage from improvements founded on any
eonsiderable innovation in habits or modes of thinking ; and
they are therefore always accompanied with practical incon-
veniences and errors, which their authors did not consider
them as hkely to be productive of. The thing in itself’ is
arbitrary: but so are our weights and measures, and mo-
nies of account; and yet what confusion should we create
amongst busy, bustling, ignorant men, if we were to abo-
lish our present system, and introduce new ones! It ap-
pears, therefore, to the writers of this essay, that the most
convenient degree of strength which cay be assumed as a
Vor. XVII, No, 67, O standard

210 On the Preparation of Indian Ink.

standard of comparison will be one which does not differ
exceedingly from that of which we have hitherto had some
indefinite idea.

§ 30. It must be recollected, however, that this circum-
stance, though it may render these tables less convenient
for practical use, by no means lessens their value, consi-
dered as a register of experimental results. It is true, they
will not give an answer with respect to equivalent quanti-
ties of liquors of all strengths by mere inspection; but we
can deduce from them, by calculation, any information
respecting this subject which we may be desirous of ob-
taining.

The modes of doing this will, of course, easily occur to
the mathematical reader: we shall, however, make no apo-
logy for presenting the public with rules and examples for
finding from these tables a solution of almost every question
which can occur in the course of practice, on the supposi-
tion that proof spirit is of the specific gravity of 920 at 60°,
and that the mode of comparison employed is that recom-
mended in § 26; and which, mutatis mutandis, will also be
applicable to any other standard which may be adopted.
They have been of some advantage to the authors in the
course of their trade, and they will probably not be useless
to society. :

[To be continued, ]

by SSR SS SS a SS Sr ee

XXXV. On the Preparation of Indian Ink; presenting an
fp aN edo : : e righ J
easy and expeditious Method of providing a Substitute
possessing all its valuable Properties. By Tuomas GiLt,
Esq.
4

To Mr. Tillcch.
SIR, ' London, Nov. 15, 1303.
ie ar

ormer communication * I mentioned that the Chi-
nese mixed their water colours up with parchment size: I
am now able to furnish you with a confirmation of that
fact, in a discovery I made a few days since, of a composi-
tion possessing all tle valuable properties of Indian ink,
which is as follows :

Boil parchment slips, or cuttings of glove leather, in
water until. it forms a size, which on being suffered to

* See our last volume, p. 272.
3 cool

On the Preparation of Indian Ink. 211

cool becomes of the consistence of jelly *: then, having
blackened an earthen plate or dish by holding it over the
flame of a candle, mix up; with a camel hait pencil; the
fine lamp-black thus obtained, with some of the above size,
while the plate 2s still warm. This black requires no grihd-
ing, and produces an ink of the very same colour; which
works as freely with the pencil; and 1s as perfectly transpa-
rent, as the best Indian ink: it possesses the advantage of
furnishing artists, &c. with a substitute for that article,
which may be prepared in situations where it might be dif-
ficult to obtain the mk itself.

If a larger quantity is required, lamp-black obtained from
the smoke of oil, tallow, &c. (that sold in the shops being
too coarse for the purpose,) may be formed into a mass
with the size; to which a little spirituous extract of musk
may be added, to give it the smell of indian Ink. When
it has obtained a proper consistence it may be pressed-into
moulds to form it into sticks, which, when dry, will be
found to agree with the real Indian ink im its property of

2 S f
rubbing smoothly on the finger nail when wetted, and leay-

ing the surface polished on becoming dry ; and, in short,
differing from it in one trifling circumstance only, namely,
that the genuine Indian ink has a yellowish metallic lustre
when dry, which may probably be owing to the mixture of
some oily or saponaccous substance, possibly ox gall: this,
however, is entircly needless.

I trust that we shall now be no more misled by the
strange accounts most writers have given of the fabrication
of Indian ink from the ink of the cuttle fish, burnt fish
bones, burnt peach stones, extract of liquorice, &c.. &c. ;
when it appears that the above two simple substances are
fully sufficient to produce an ink possessing every good pro-
perty that can be desired. [ am, Sir,

Your most obedient servant,
Tuomas GiLL.

* If it is thought too much trouble to prepare the parchment size, a
solution of good common carpenter's glue, of the consistence described,
may be employed in its stead,

02 XXXVI. An

{ 212 j

XXXVI. dn Account of some Experiments and Observa-
tions on the constituent Parts of certain astringent Vege-
tables ; and on their Operation in Tanning. “By Hun-

PHRY Davy, Esq. Professor of Chemistry in the Royal
Institution.

‘

[Continued from p. 76.]

Ill. Experiments and Olservations on Catechu or Terra
Japonica.

Tae extract called catechu is said to be obtained from the
wood of a species of the mimosa*, which is found abun-
dantly in India, by decoction and subsequent evaporation.

’ There are two kinds of this extract; one is sent from
Bombay, the other from Bengal; and they differ from each
other more in their external appearance than in their che-
mical composition. The extract from Bombay is of an
uniform texture, and of a red brown tint, its specific gra-
vity being generally about 1°39. The extract from Bengal
is more friable, and less consistent; 1ts colour ts lke that
of chocolate externally, but, when broken, its fracture pre-
sents streaks of chocolate and of red brown. Its specific
gravity is about 1:28. Their tastes are precisely similar,
being astringent, but Ieaving in the mouth a sensation of
sweetness. “They do not deliquesce, or apparently change,
by exposure to the air.

The discovery of the tanning powers of catechu is owing
to the president of the Royal Society , who, concluding from
its sensible properties that it contained tannin, furnished
me, in December 1801, with a quantity for cherie exa-:
mination.

fn my first experiments, I found that ine solutions of

catechu copiously precipitated gelatine, and speedily tanned
skin; and, in consequence, I began a particular investiga-
tion éf their properties.

The strongest infusions and decoctions of the two dif-
ferent kinds of catechu do not sensibly differ in their na-
ture, or in their~ composition. ‘Their colour is deep red
brown, and they communicate this tinge to paper; they
slightly redden. litmus paper; their taste is highly astrin-
gent, and they have no perceptible smell.

The strongest infusions that I could obtain from the two
kinds of catechu, at 48° Fahrenheit, were of the same spe-
cific gravity, 1°057: but, by long decoction, I procured so-

* See Kerr. Medical Observations, vol. ve p. 1§5- "
lutions.

On the constituent Paris of astringent Vegetables. 215

Jutions of 1*102, which gave, by evaporation, more than
4-6th of their weight of solid matter.

Five hundred grains of the strongest infusion of catechu
from Bombay, furnished only 41 grains of solid matter;
which, from analysis, appeared to consist of 34 grains of
tannin, or matter precipitable by gelatine, and 7 grains that
were chiefly a peculiar extractive matter, the properties of
which will be hereafter deseribed. The quantity of solid
matter given by the strongest infusion of the Bengal cate-
chu was the same, and there was no sensible difference in
its composition. Portions of these solid matters, when in-
cimerated, left a residuum which seemed to be calcareous ;
but it was too smal] in quantity to be accurately examined,
and it could not have amounted to more than ;},th of their
original weights.

The strongest infusions of-catechu acted upon the acids
and pure alkalis in a manner analogous to the infusion of
galls. With the concentrated sulphuric and muriatic acids,
they gave dense light fawn-coloured precipitates. With
Strong nitrous acid they effervesced ; and lost their power
of precipitating the solutions of isinglass, and the salts of
iron. ‘The pure alkalis entered into union with their tan-
uin, so as to prevent it from being acted upon by gelatine.

When the solutions of lime, of strontia, or of barytes,
were poured into the infusions, copious precipitates, of a
shade of light brown, were formed; and the residual fluid
assumed a paler tint of red, and was found to have lost its
power of precipitating Anse i

After lime had been boiled for some time with a portion
of the infusion, it assumed a dull red colour. The liquor
that passed from it through the filter had only a faint tint
of red, did not act upon gelatine, and seemed to contaii
only a very small portion of vegetable matter. Pure mag
nesia, when heated with the infusion, acted upon it in an
analogous manner; the magnesia became light red, and the
residual fluid had only a very slight tinge of that colour.
With carbonate of magnesia, the infusion became deeper
in colour, and lost its power of precipitating gelatine }
though it still gave, with oxygenated sulphate of iron, a
light olive precipitate.

The carbonates of potash, of soda, and of ammonia, in
their concentrated solutions, produced only a slight degree
of turbidness in the infusion of catechu: they communi-
eated to them a darker colour, and deprived them of the
power of acting upon gelatine ; though this power was re-
stored by the addition of an acid,

O 3 After

214 Experiments and Observations on the

After the mixture of the solution of carbonate of potash,
and the infusions had been exposed to the atmosphere for
some hours, a brown crust was found to have formed upon
its surface, and a slight precipitation had taken place.

The salts of alumime precipitated the infusions, but less
copiously than they precipitate the infusion of galls. A
sunilar effect was produced by nitrate of potash, sulphate
of magnesia, prussiate of potash, and many other neutral
salts.

The nitrate, or acetite, of lead, in concentrated solution,
when poured into the infusion praduced in it a dense light
brown precipitate, which gave to the fluid a gelatinous ap-

earance. After this effect, there was no free acid found
in it; and both the tannin and the extractive matter seemed
to have been carried down in union with a portion of the
metallic salt.

The solution of murjate of tin acted upon the infusion of
eatechu in a manner similar to that in which it acts upon
the infusion of galls.

The least oxygenated sulphate of iron produced no
change in the infusion. With the most oxygenated sul-
phate it gave a dense black precipitate, which, when dif-
fused upon paper, appeared rather more inclined to olive
than the precipitate from galls.

The infusions were precipitated by the solution of al-
bumen.

The precipitates by gelatine had all a pale tint of red
brown, which became deeper when they were exposed to
the air.. The compound of gelatine and the tannin of the
strongest infusions of catechu appeared, by estimation of
the quantity of isinglass in the solutions used for their pre-
cipitation, to consist of about 41 parts of tannin and 5g of

elatine.
~ Of two pieces of calf-skin which weighed, when dry,
132 grains each, and which had been prepared for tanning,
one was immersed in a large quantity of the infusion of
catechu from Bengal, and the other in an equal portion of
the infusion of that from Bombay. In less than a month
they were found converted into leather, When freed from
moisture, by long exposure in the sunshine, they were
weighed. ‘The first piece had gained about 34 grains, and
the second piece 354 grains. The leather was of a much
deeper colour than that tanned with galls, and on the upper
surface was red brown. It was not acted on by hot or cold
water; and its apparent strength was the same as that of
similar leather tanned in the usual manner. ?
Any

a a ee ee

constituent Parts of astringent Fegetatles. 215

In examining the remainder of the infusions of catechu,
in which skin had been converted into leather, ‘I found in
them much less extractive matter than I had reason to ex-
pect, from the comparative analysis of equal portions of
the unaltered infusions made by solutions of gelatine. At
first, I was inclined to suppose that the deficiency arose
from the action of the atmosphere upon the extractive mat-
ter, by which a part of it was rendered insoluble. But, on
considering that there had been very little precipitation in
the process, I was led to adopt the supposition, that it had
entered into union with the skin at the same time with the
tannin ; and this supposition was confirmed by new expe-
riments.

Both kinds of catechu are almost wholly soluble in large
quantities of water; and, to forma complete solution, about
18 ounces of water, at 52°, are required to 100 grains of
extract. The residuum seldom ainounts to {;th of the ori-
Binal weight of the catechu: and, in most cases, it is found |
to consist chiefly of calcareous and aluminous earths, and
of fine sand, which, by accident or design, had probably
been mixed with the primitive infusion at the time of its
evaporation.

A considerable portion of both kinds of catechu is soluble
in alcohol; but, after the action of alcohol upon it, a sub-
stance remains of a gelatinous appearance afid a light brown
colour, which is soluble in water, and is analogous in its
properties to gum or mucilage.

The peculiar extractive matter in the catechu is much
less soluble in water than the tanning principle; and, when
a small quantity of water is used to a large quantity of ca-
techu, the quantity of tannin taken up, as appears from the
nature of the strongest infusion, is yery much greater than
that of the extractive matter.

The extractive matter is much more soluble in warm
water than in cold water; and, when saturated solutions of
eatechu are made in boiling water, a considerable quantity
of extractive matter, in its pure state, falls down as the
liquor becomes cool,

The peculiar extractive matter of the catechu may be
likewise obtajned by repeatedly lixiviating the catechu, when
in fine powder, till the fluids obtained cease to precipitate
gelatine; the residual solid will then be found to be the
substance in question,

The pure extractive matter, whether procured from the
Bombay or Bengal catechu, is pale, with a faint tinge of
red brown, It has no perceptible smell ; its taste is slightly

mows astringent ;

216 Experiments and Observations on the

astringent ; but it leaves in the mouth, for some time, a
sensation of sweetness stronger than that given by the ca-
techu itself.
Its solution in water is at first yellow brown; but it gaing
a tint of red by exposure to the air. Its solution in alcohol
does not materially change colour in the atmosphere ; and
it is of an uniform dull brown. /
The extractive matter, whether solid or in solution, was
= found to produce any change of colour upon vegetable
ues. . .
It became of a brighter colour by the action of the al-
kalis; but it was not precipitated from its solution in water
by these bodies, nor by the alkaline earths.

The aqueous solution ‘of it, when mixed with solutions

of nitrate of alumine:and of muriate of tin, became slightly
turbid.

To nitrate of lead it gave a dense light brown precipita-
tion. — rt

Is was not perceptibly acted upon. by solution of gela-
tine; but, when solution of sulphate of alumine was added
to the mixture of the two fluids, a considerable quantity of
solid matter, of a light brown colour, was immediately de-
posited.

To- the solution of oxygenated sulphate of iron it com-
municated a*fiffe grass green tints anda green precipitate
was deposited, which became black by exposure to the air.’

It was not precipitated by the mineral acids.

Linen, by being boiled in the strongest solution of the
extractive matter, acquired a light red brown tint. The
Jiquor became almost colourless; and, after this, produced
very little change in the solution of oxygenated sulphate of
iron. ‘ mR it Do

Raw skin, prepared for tanning by being immersed in
the strong solution, soon acquired the same kind of tint as
the linen. It united itself to a part.of the extractive mat-
ter; but it was not rendered by it insoluble in boiling water:

The solid extractive matter, when exposed to-heat, soft+
ened, and became darker in its colour, but did not enter

into fusion. At a temperature below that of ignition, it.

was decompounded. The volatile products of its decom-
position were, carbonic acid, hydrocarbonate, aud water
holding in solution acetous acid and a little unaltered ex-
tractive matter. There remained a light and very porous

charcoal. * :
In considering the manner in which the catechu is pre=
pared, it would be reasonable to conclude that different spe-
: et cimens

constituent Parts of astringent Vegetables. 217

cimens of that substance must differ in some measure in
their composition, even in their pure states; and, for the
purposes of commerce, tliey are often adulterated to a con-
siderable extent with sand and earthy matter *,

In attempting to estimate the composition of the purest
catechu, I selected pieces from different specimens, with
which I was supplied by the president, and reduced them
together into powder; mixing, however, only those pieces
which were from catechu of the same kind.

Two hundred grains of the powder, procured in this way
from the catechu of Bombay, afforded by analysis

Tannin - - - - 109 grs.
Peculiar extractive matter - =. 68
Mucilage - - ae a th a
Residual matter, chiefly sand and calcareous

earth - - - 10

The powder of the Bengal catechu gave, by similar mes
thods of analysis, in 200 grains,

Tannin - - - - = 97 gTs.
Peculiar extractive matter = = Pepi 73
Mucilage - ee. a 24. Oo
_Residual matter; sand, with a small quan- :

tity of calcareous and aluminous earths, 14

In examining those parts of the catechu from Bengal
which were differently coloured, I found the largest pro-
portion of tannin in the darkest part of the substance ; and
niost extractive matter in the lightest part. It is probable
that ‘the inequality of composition in this catechu is owing
to its being evaporated and formed without much agitation ;
in consequence of which the constituent parts of it that are
least soluble, being first.precipitated, appear in some mea~
sure distinct from the more soluble parts, which assume
the solid form at a later period of the process.

From the observations of Mr. Kerr +} it would appear that
the pale catechu is that most sought after in India; and it
is evidently that Which contains most extractive matter.
The extractive matter seems to be the substance that gives
to the catechu the peculiar sweetness of taste which follows
the impression of astringency; and it is probably this
sweetness of taste which renders it so agreeable to the Hin- .
doos, for the purpose of chewing with the betle-nut.

; ( [ To be continued. ] °

* One specimen that I examined of the terra japonica of commerce;
furnished, ‘by incineration, one-fifth of sand and earthy matter; and any
other specimen nearly one-sixth.

+ Medical Obseryations, vol, wv Pp 955,

XXXVIF, OF

XXXVII. Of the Herring Fishery. Translated from the
French of M. DvnameE and others*.

Of the Spawning Seasons.

1B. is well known that herrings do not all spawn at the
same time and it is generally observed that in the years
that the air is mild they spawn sooner than when the sea-
son has heen very cold. Sometimes, for instance, a great
quantity of shotten herrings is caught in the beginning at
December, whereas in other years, ereat numbers of full
ones are found i in January. This.is a general observation ;
and if we inquire more particularly into the business, we
shall find that some herriugs spawn much sooner than
. others; so that in October, when almost all the herrings
that come into the Channel are full, there are some shotten
ones found among them,

Some fishermen think that in the Enelish sea the
spawning season is in October: this may be ‘the case as to
some herrings, but not as to the greatest number. How-
ever, towards the middle of November they take shotten
herrings at Yarmouth, though not in as great quantities as
in the Channel, w hee shotten herrings are : sometimes found
in the middle ‘of October. The common opinion is, that
herrings spawn but once a year, and that they come into
our seas for that purpose. It is certain that they spawn
near our coasts; and the condition of the eggs of the
herrings that are taken at Shetland compared with that of
the eggs of those that are taken at Yarmouth and in the
Channel, actually seems to prove that they come into our
seas ON purpose to spawn, Nevertheless, if we eonsider
the immense quantities of them that come fram the north,
we shall be inclined to think that some of them spawn
there. They are, perhaps, like the bees, that multiply in
their hives, and send out swarms when they become too
numerous.

Shotten herrings do not constitute a distinct species from
the others. They are those which have discharged their
eggs or milt, and are therefore generally worse than the full

eneés, on ee of the sickness that they are subject to at
the time of spawning, and because the most of them are
caught before they are recovered, whereas the greatest part
of the herrings quit the coasts a short time after they have
spawned.

* From Treaasactions of the Dublin Society, vol-i, part 2.

of

Of the Herring Fishery. 819

Of the Seasons in which Herrings are found in different
Places, and of the Variations that occur in the Courses

they take.

In the beginning of spring the inhabitants of the North
take a great quantity of herrings in their own seas. In June
and July the fishery is carried on near the Shetland islands.
In September and October the fishermen take up their quar+
ters at the entrance of the German sea, and near the coasts
of the north of England: this is called the Yarmouth fish-
ery. When it is over, they follow the herrings into the
Channel in October, November, and December. It ap-
pears, therefore, that the herrings come from the North
by the Orkney islands, and that, after having touched upon
the coast of Norway, they cross the North sea to come to
the north of Scotland and England, whence they proceed
through the Streights of Dover into the Channel, where
the greatest part of them spawn ; after which they disap-
pear, and several are of opinion that they return to the North
along the coasts of Ireland.

It having been observed that the herrings leave the North
towards April or May, the Dutch used formerly to go in
quest of them near the Island of Helygeland and the coast

‘of Norway. But as that fishery often proved but middling,

they do not set out now until June, at which time they go
to meet them between Shetland and Newcastle.

OF THE HERRING FISHERY IN THE CHANNEL.

Of the Orders issued by the French Government not to con~
tinue the Herring Fishery in the Channel after the Month
of December.

There are two things that contribute to the prosperity of

a branch of commerce. The one consists in meriting the
confidence of the purchasers, by taking particular care to
have the article well conditioned, and, above all, in observing
great fidelity in the expediting of it; the other consists in
obtaining a preference by keeping the article at a moderate
rice. It was with a view to these objects that the Dutch,
having perceived that the herrings caught between the rocks
of Ireland, Shetland, and Norway, were not of a good quas
lity, have prohibited fishing in those places. They have
also made regulations concerning their salt works, so as to
have salt of a good quality; and for the purpose of keep-
ing it at a low price, they have not only no salt tax, but

- they even giye encouragement to those who carry on salt

works,

£20 Of the Herring Fishery.’

works. And in France, the merchants that cure salt fisk
get salt at a moderate price, that they may be enabled to
sell their fish at nearly the same price that the Dutch do.
For similar reasons regulations have been made concerning
the time that the herring fishery should cease.

The herzings come from the north of England into the _
Channel ; they are certainly poorer there than they were in
the North, or'evén on what is called the Yarmouth coast.
However, they are still very good, either fresh or salted ;
and, as we have said elsewhere, the fattest herrings are not
the best for salting. The fishing for herrings has therefore
been always allowed, from the time that they come ito the
Channel until the latter end of December; but from that
time it has been prohibited by several-orders of government.
We shall now mention the reasons of this prohibition.

It is certain that a great quantity of herrings spawn mm
the Channel, and especially towards the mouth of the Seine,
im the end of the season, whereby they lose much of their
good quality, particularly for salting. About that period
there are some shotten ones taken that are very good fresh 5
but- when they have not had tune to reeover from the
spawning sickness, they dry up in the salt, and becomé
what they call horny; whereas in October and November
numbers of them are full and very good, either fresh or
salted» This, however, must be understood of what usu-
ally happens; for there are some late seasons m which the
abundance of shotten herrings does not come on until Ja-
nuary, or evensFebruary. As salt shotten herrings were
known to be inferior to the full ones, it was prohibited, by
a decree of March 24, 1687, to continue this. fishery after
the month of December, or to purchase herrings from fo-
reigm vessels after that time; and in confirmation of this
prohibition another decree was issued in 4759, wherein 18
added an order not to bying any such herrings to market 5
which has been since confirmed by several regulations,

The motives of these prohibitions were, that the herrings
salted.in that season were bad, and that thereby all those of
the Channel were brought into disrepute; that they were
unwholesome and caused diseases; and that the fishing for
herrings in:that season was destructive of the species.

Lhere were some representations made against these de-
exees, and the iishermen of several ports alleged that her-
rings do not spawn on the coast of Normandy. But this

lea could not stand, as it was manifestly false.

They added, thatthe Irish do not prohibit this fishery

OW on
4

Of the Herring Fishery. Ot

on their coasts, where there are great quantities of shotten
herrings. But should the Irish be wrong in allowing it, it
does not follow that the French should imitate them.

On the other side, the herring merchants, who applied
for these. prohibitions, had probably their own advantage
im view, viz. the seiling their fish dear, rather than that of
commerce, They alleged that shotten herrings were un-
wholesome, and caused diseases. But there is no founda-
tion for this assertion, although’ we shall readily grant that
they are not as pleasing food as full herrings.

‘And as to the third plea, viz. that the fishme for her-
rings after December was destructive of the species, it was
avery nugatory one, not only because the quantity of her-
rings that the fishermen can take is a mere trifle compared
with the immense quantities of them that are destroyed by
multitudes of fish that feed upon them, but also because,
were the multiplication of the species to be considered, it
would-be much more proper to prohibit the fishing for full
herrings.

The only plausible reason for niaking the above-men-
tioned regulations was, that, as shotten herrings are not as
good as full ones when salted, it was to be apprehended,
that if the taking and salting them were allowed it would
bring all the salted herrings of the Channel into disrepute ;
which would be very hurtful to trade. But still it is hard
that the poor should be deprived of an article of food which
could be procured very cheap.

The fishermen of Dieppe, having represented that her-
rings were absolutely necessary for baiting their hooks, have
obtained leave to fish -for them with a few small boats, under
condition of cutting off the heads and tails ef such as they
should take. This favour has been granted also to some
other ports. Now, if a regulation of this kind were genc-
rally adopted, it would’be of great.service to the fishermen’
and to the poor, without injuring the herring trade. For,
by taking care that the heads of such herrings as are caueht
after December should be cut off, it will be easy to distin-
guish the good ones from those of an inferior kind, and the
purchasers of salt herrings will be ‘sure not to be imposed
upon.

Of the Circumstances thought to. le favourable to the Herring
) Fishery.

The fishery is expected to be good, when aficr a troubled

sea there Comes on a calm, accompanied with a mist or

thick fog ; when the wind blows from the north ornorth-
west,

e22 Of the Herring Fishery:

west, or rather from that part of the horizon wheneé the
herrings usually come: for in these cases they come sooner
and in greater numbers to our coasts: Those wirids gene-
tally blow from a northern direetion, and are the same that
bring woedcocks to our coasts; and therefore it is supposed
that the herring season will be good, when there is plenty
of woodeocks:

When a great numbet of sea birds assemble in any par-
ticular place, it is an almost certain sign that there is abun-
dance of herrings there: It is also a good sign to catch
sea dogs, as they follow the herrings to feed upon them.
Another good sign is; when the water is agitated to a cer-
tain depth; likewise when there are fat or greasy spots
floating like oil upon the sea; when not much troubled.

Lights kept in the fishing boats are rather serviceable
than hurtful to the fishery, but great lights commig from
land drive the fish away: It 1s fat to be observed that the
ebbing or flowing of the tide is immaterial; but that the
greatest quantity of fish is usually caught when the water
1s smooth.

Of the Pec Herrings, or those taken most early in the
Northern Seas by the Dutch.

These herritigs are very fat and large; they are delicate

and pleasing to the taste; and are ood when salted: but as

they are fat and oily it requires much care to preserve them; ~

and they are never as white as the herrings that are salted
on our coasts. There are but very few shotten ones found
amongst them. The greatest part of them have milt or eggs;
which are only beginning to be formed:

Of the Herring Fishery near Shetland:

The Dutch usually set out for this fishery towards the
middle of June, but never begin it until the evening of St.
John’s day. They do not fish in the day-time, and the
manner of fishing there is nearly the same as that of the
Yarmouth fishery. The best situation for this north fishery
is from the small Island of Fairhill to the north-west of the
Orkneys and round Shetland.

OF THE YARMOUTH FISHERY<

~The Dutch and French carry on this fishery as well as’

the English ; with this diffcrence, however, that they aré
not allowed to come near the coast of England, in the vi-
cinity of which the English fish themselves. It is called

the Yarmouth fishery, because a great part of the herrings,

that

Of the Herring Fishery. 293

that are caught by the’English are brought fresh to Yar-
mouth, where they are cured. This fishery is generally
more profitable to the English than that of green or dry
cod; and therefore to encourage it they have exempted it
from all sorts of duties. The fishermen take only a licences
As the Dutch and French are not allowed to bring their
herrings to England, they salt them on board their busses.

Description of the Yarmouth Herrings.

They are not as large or as oily as the pec or North sea
herrings, although they are originally the same. But they
are firmer, their milts are larger, and the eggs better formed;
on which account they are much better for salting and keep-
ing than the pecs. For this reason the English and Scotch
do not fish for herrings at a great distance from land, where
they are very fat. In fact, the Yarmouth herrings are the
best of all for salting.

It is easy to conceive that herrings lose their fat and oil
through the change of climate, water, and food. The dif-
ferent qualities, however, of cured herrings depend very
much upon the care that is taken in salting them, as will
appear hereafter. for instance, as it is a matter of great
importance that herrings should be put in salt on their
coming out of the water, those that the Dutch and French
take in the Yarmouth fishery have this advantage, because
such as are caught at night are: salted on board in the day-
time; which is not the case when herrings are carried fresh
into port, on account of the contrary winds, or other acci-
dents, that prevent the landing and delivering them as soon
as would be requisite.

Of the Herring Fishery on the Coasts of Ireland and
Scotland.

The herring fishery of Ircland is very like that of Yar-
mouth, and the Irish sea abounds with herrings from Au-
gust to October. In Scotland, instead of smoking their
herrings, as was formerly the custom, they. make white
herrings, either because, on account of the herrings having
removed from the coast, they are obliged to salt them on
board their vessels, or because white herrings are preferred
in Italy.

Of the Salting of Herrings at Sea.

The English engaged in the Yarmouth fishery keep very
near the coast, and therefore bring their herrings to Iand
Soon atter they are caught. But the fishers of the Channel,
'. P

as

204 Of the Herring Fishery.

as they often go out far from Jand, and are therefore ap~
prehensive the fish may be spoiled before they can return to
port, take with them some barrels of salt for the purpose of
at least corning the herrings, so as that they may keep for
some days : however, this sort of preparation is not suffi-
cient for the herrings that they take in the North and Yar-
mouth fisheries; they must be at least casked, and even
barrelled as far as possible. The Dutch and French that go
out or these fisheries practise this preparation, and the me-
thod of doing it is generally as follows :—The Norman fish-
ermen place the herrings in different compartments upon
the deck: they open their necks a little with a small knife,
and take out the gills, and at the same time draw out the sto-
mach and intestine; this is called dressing the herrings; they
are then put into baskets, and carried behind to be poured
into large vats with 2 quantity of salt. In these the her-
rings and salt are stirred about, after which the herrings are
put into tubs: but in this state they could not keep many
days; andtherefore when the men cannot return soon to
port they put them into barrels, pressing them together as
close as possible. They are often obliged to go through
these operations in too great a hurry, on account of bad»
weather, or for the purpose of clearing the deck, &c.; so
that sometimes they corn or barrel herrings that were not
dressed. There is an order of parliament against salting or
barrelling such herrings. But, whatever precautions may
be taken at sea, the barrels must be emptied on land, and
the herrings made up again with greater care, as will be
explained hereafter.

Of the Salt used in the various Methods of curing.

Tn whatever manner herrings are to be cured, salt must
be used ; but there are different sorts of salt, some of which
are not good for this purpose. ;

The sorts of salt that the French use are those of Poitou,
Saintonge, Britany, and Nermandy. Every one allows
that of Brouage to be the best of all. It 1s made _m the salt
marshes of Brouage, Marans, the Isle of Ré, and other

arts of Saintonge and Poitou.

When the Brouage salt is old, and has become dry and
sweet, it leaves to the herrings their good taste, without
communicating any sharpness, or breaking them, or making
them tough or shrivelled. As to the salt of Britany, besides _
what is used in the province, the Flemings and Picards take
some of it, which they refine and make white. This re-
fined salt is thought to be more sharp and corrosive 7

; thé

Method of preparing Black Oxide of Mercury. 225

the gray salt of Brouage: however, for this very reason
some people think it is advantageous to mix some of it with
that of Brouage, when the herrings are fat and oily. Some
use the salt brought back from Newfoundland. The reader
may see what we shall say of this salt in the Essay on Cod
Fish. Provided it be not old salt that fell from the heaps
of cod, it may do very well, particularly if care has been
taken to dry it well in the sun upon sails.

The neighbouring nations use white Spanish and Portu-
guese salt, in which the English and Dutch carry on a con-
siderable trade. The greatest part of the salt used by the
northern nations is brought from St. Ubes in Portugal.

This salt looks infinitely finer than that of Brouage, but
is of a much inferior quality; and the Dutch, who know
this well, sometimes mix Brouage salt with Spanish or Por-
tuguese salt, which mixture is allowed to be preferable to
pure Brouage salt, when the fish is fat and oily; and it is
said that it contributes to the superiority of the Dutch salt
herrings. This may be true: we shall see, however, in the
sequel, that the perfection of the Dutch herrings in general
1s owing to the great care they take during the whole pro-
’ cess of curing them.

In Holland all the salt to be used in curing herrings must
be examined, before it is embarked, by juries of the respec-
tive places, to show that it is of a good quality and clean.
The fshermen must get a certificate to this purpose, under
the penalty of paying a fine of twenty-five florins.

Of the Barrels for Salt Herrings.

There is an order in Holland that the barrels must be
marked with the cooper’s mark, and then examined in pub-
lic by juries, who reject such as are not of good wood, or
which might give a bad taste to the fish; after which the
mark of the city is put upon them. There are also in
France many regulations relative to the size, condition of
barrels, &c.

[ To be continued. }

XXXVIIT. Improved Method of preparing Black Oxide of
Mercury. By M. Scuuuze, of Kiel*.

Tuoven several methods have been proposed for pre-
paring black oxide of mercury since that substance was

* From Scherer’s Allgemeines Journal dev Chemie, no» 47-

Vou. XVII. No. 67. P used

206 Improved Method of preparing’

used as a medicine, it must, however, be allowed that-eaclt
of these methods is attended with inconveniences, and that
the best, even when the materials are of the first quality,
does not produce that advantage which might be expected.
Without enlarging further on the processes hitherto em-
ployed in the preparation of this article, I flatter myself it
will not be considered superfluous if I here make known a
very convenient method founded on true chemical princi-
ples, which, besides its great simplicity, gives a rich and
pure product : advantages which must certamly recommend
it to the notice of every apothecary. :

In the description of the process I hope I shall be par-
doned for being circumstantial, as minuteness is often of
great utility, and, in regard to a matter of so miuch simpli-
city, can be attended with no hurt. .

Mix one part of pure concentrated nitric acid with four
parts of distilled water in a narrow-necked retort 3 and
having added four parts of pure mercury, place the vessel
in warm sand of the temperature of from 120° to 140° of
Fahrenheit. Maintain this heat till the action of the acid
on the metal has apparently ceased ; that is to say, till no
more bubbles arise. ;

When the operation has been carried this length, the
heat of the sand must be raised to from 200° to 210° of
Fahrenheit ; and this temperature must be maintained for
three or four hours. Then bring the fluid to a slight state
of ebullition, and, haying continued it without interruption
for half an hour, pour the whole, boiling hot, into a glass
vessel containing fifty parts of distilled water, with which
it will mix exceedingly well by continual stirring. )

In the aboye operation the following circumstances are to
be remarked :

ist. Should a commencement of crystallization manifest
itself during the digestion or boiling of the solution, a little
warm water must be immediately added, to prevent the com-
plete crystallization of the matter, because:the solution ac-
quires a strong propensity towards it as soon as too large a
quantity of the water has been evaporated during the pro-
cess.

2d. Some metallic mercury must remain at the end of
the operation. Should all the mercury, however, be dis-
solved, it will be necessary to add some more of the metal,
and to complete the solution as before directed. ,

The diluted solution obtained in this manner is then fil-
tered, and the mercury remaining on the filter is collected
and put into another clean vessel,

3 From

Black Oxide of Mercury. 297

From the clear fluid a black precipitate is gradually
thrown down by means of ammonia, and more ammonia —
must be dropped into it till no more precipitate is formed.
By these means the precipitate from the beginning to the
end of the operation will be uniformly black, and more
black oxide will thus be obtained than by the methods hi-
therto employed. Should the precipitate be of a brighter
colour towards the end of the operation, which, however,
will not be the case when the above prescription is closely
followed, the fluid must be separated from the precipitate
before the precipitation is completed, and the remaining
fluid must then be precipitated by itself. The last preeipi-
tate is to be kept for a future preparation, or for any other
use.

Wash the black precipitate which has been obtained, in
a glass vessel with cold distilled water, and place it on a
paper filter, where in a few hours it will be freed from the
greater part of its moisture. Then twist together the ex-
tremities of the filter, so that none of the precipitate can
escape from it; and having wrapped it up in a few folds of
blotting-paper, subject it to a press, or place weights over
it: but this must be done with great care, lest the paper
should burst: it must, however, be well pressed at last, in
order to free it as much as possible from water.

When this is done, take the filter from the press; and
having freed it as speedily as possible from the wrapping
paper, spread it out carefully on some solid supporter, ex-
tending the dry precipitate in a thin stratum. Suffer it to
dry completely in a temperature which must not exceed 70°
of Fahrenheit. By these means you will obtain a prepara-
tion which will stand every proof in regard to its purity.

I shall conclude this account with a few observations on
the process in general, and on some individual parts of it.

ist. The principle on which this method is founded is
experience, which shows that acids in general are capable
of taking up any metallic oxide, according as it is more or
less oxidated.

2d. When mercury and nitrous acid exposed to heat
are suffered to exercise an action on each other till the dis-
engagement of air-hubbles ceases, a combination will be
obtained in which the oxide of mercury has experienced
a stronger degree of oxidation than. is necessary for black
oxide of mercury, as this solution is precipitated white
by ammonia. Bat if mercury not oxidated remains in.
contact with the solution during the continuance of the ex-
posure to heat, a part of the oxygen passes from the dis-

a} solved

228 On the Stones said to have

solved oxide of mercury to the metal not oxidated, which,
according to the above principles, must be abundantly taken
up. This effect continues till all the oxide of mercury in
the solution is brought to the utmost degree of oxidation.

sd. By this process, therefore, the whole of the dissolved
oxide of mercury is reduced to a uniform low degree of
oxidation, and the solution thereby rendered proper for pro-
ducing, from the beginning to the end of the precipitation,
black oxide of mercury.

4th. The reason why the boiling solution is immediately
poured into a large quantity of water is, because on cooling
most salts crystallize from their solution, and are then dif-
ficult to be dissolved. But should the whole solution crys-
tallize during the process by too great evaporation of the
water, it would be necessary to add some nitrous acid, di-
luted with the necessary quantity of water, to dissolve the
whole by boiling, and then to proceed as before.

The whole cannot be again dissolved by water, because
during crystallization a part of the nitrate of mercury is
decomposed, and the separated oxide of mercury is so much
oxidated that the remaining nitric acid is not in a condi-
tion to bring it to a clear solution.

5th. The pressing of the precipitate contributes in a con-
siderable degree to the speedier conclusion of the whole pro-
cess, because during the operation of drying a strong heat,
in consequence of the reasons before mentioned, cannot be
employed. When the moist as well as the dry black oxide
of mercury is exposed to a temperature which approaches
that of boiling water, its black eolour is changed to gray,
and if the temperature be still further raised it becomes en-
tirely white; nay, by a still higher temperature it soon as-
sumes an orange colour : which, however, is an evident sign
of increasing oxidation. The before-mentioned degree of
heat must, therefore, not be exceeded in the operation of
drying, and the precipitate must not even be washed with
hot water if it be required to o}tain this preparation in the
proper state.

KXXNIX. On the Stones said to have fallen from the
Atmosphere. By J, DELALANDE.

"
Tue stones which felt ‘near Laigle on the 26th of April
1803 have afforded considerable occupation to philosophers.
As a globe of fire which burst with a great noise had been
seen, it appears to me that this phenomenon may “3

: referred

fallen from the Atmosphere. — 239

referred to fire-balls, of which I have mentioned thirty-six
instances in the Connoissance des Tems for the year 8 and
the year 10. The work of M. Izam entitled Lithologie
Atmosphérique contains many details on this subject.

These stones being of a species not to be found on the
earth, it has been concluded that they are formed in the at-
mosphere ; but several chemists consider this as impossible.
M. Delaplace has examined what would be the case if they
were projected from a lunar volcano; and N. Poisson, an
able geometrician, professor in the Polytechnic School, has
given a learned memoir on this subject in the Bulletin des
Sciences *, published by the Philomatic Society; from which
it results, that if a body were projected from the moon with
a velocity of 7600 fect per second, or five or six times that
of a cannon ball, it would reach the earth in two days and
a half, and its velocity when it arrived at the surface would
be 31500 feet per second, making allowance for the resist-
ance of the air.

But as the height of the atmosphere may be considered
as yery small in comparison of the earth’s semidiameter,
this velocity would be nearly equal to that which the same
body would have on entering into this atmosphere ; but the
air then acting upon it by the resistance, which increases in
a proportion much greater than the velocity, would soon
lessen the rapidity of this motion, which would become
sensibly uniform, like that of bodies which fall into a resist-
ing fluid of considerable depth.

M. Biot, who was at Laigle to collect all the circum-
stauces of this phenomenon, presented to the Institute a
very long and satisfactory report on this subject, which has
been printed. From the circumstances which he relates,
it appears to me difficult not to believe that these stones
were formed at the same time as the globe of fire. The
number which fell was two or three thousand: they were
exceedingly hot, scorched at the surface, and almost fria-
ble; but they became hard on eooling.

M. Izam has made no mention of the stones which fel
on the 16th of June 1794, seven leagues to the south-west
of Sienna in Tuscany, and respecting which there is a work
entitled Sopra piogetta di sassi accaduta nella sera de 16 Gi-
ugno 1794, Dissertaxione del P, D. Ambroxié Soldani in
Siena 1794, 8vo. Fifty or sixty fell in the compass of a
mile: they were hot and burning at the surface, like those

* No. 71-
P3 which

230 Extracts from the third Volume of

which fell at Ensisheim, November 7, 1742; at Bourg, in
Bresse, September 1753; at Agen, July 24, 1790; in York~-
shire, December 1795; at Salles, near Villefranche, in Beau-
jolais, March 12, 1798; and at Benares, December 1798.
M. Lesage explains their formation in the atmosphere * ;
but even if this should not be explained by the chemists, I
shall, till the philosophy of meteorology is further ad~
vanced, consider them as an atmospheric production.

XL. Extracts from the third Volume of the Analyses
of M. Kuaprotu.

[Continued from p. 83°]

Grayish White Phosphated Ore of Lead.

Accorpmxe to M. Klaproth’s analysis, this gray ore of
lead, crystallized in thin and very brilliant prisms, is com~-
posed of 42 oxide of lead and one part phosphoric acid. He
Js not acquainted with the matrix of this ore, which he very
much regrets, as white phosphated ores of lead are exceed~
ingly rare. This species of ore proves how uncertain are
the signs borrowed from colours for the classification of
minerals. Jt is proper to remark that the muriatic acid dis-
covered in phosphated ores of lead is always found in them
In nearly the same proportions.

Analysis of the Phosphated Lead Ore of Anglesey.

The sulphated lead ore of the Parisle Mountain of the
Island of Anglesey is found in small insulated crystals, the
form of which appears to be an inclined pyramid of four
faces. They are always inclosed in a hard stratum of brown
ochre, sometimes uncoloured and without spots; but often
embrowned by a slight tint of ochre: in the inside they

Mave great brilliancy.

_ Their specific gravity is 6300: exposed on charcoal to
the blowpipe they decrepitate as soon as the flame touches
them. When reduced to powder they fuse into a brilliant
scoria, which is at length converted into a button of me-

tallic lead,
* Journal de Physique, Messidor, an. ry,

This

the Analyses of M. Klaproth. 931

This ore contains

Oxide of lead - - - 71
Sulphuric acid - - 24°80
Water of crystallization = - 2
Oxide of iron - - > 1
98°80

The oxide of iron must be considered rather as a mecha-
nical mixture of the ochrey crust with this ore, than as one
of its constituent principles.

Analysis of the Sulphated Lead of Leadhills.

The sulphated ore of lead of Anglesey was the only one
known till the discovery of that of Leadhills in Scotland ;
the chemical principles of which are the same; but they
differ in their external characters, since it crystallizes in
tablets. These crystals are colourless, in several places
transparent, and have a very brilliant splendour.

The vein of this ore is situated at Wanloch-head, near
Leadhills, ,

When exposed on charcoal to the blowpipe it exhibits
the same phenomena as that of Anglesey.

A hundred parts of these crystals of sulphated lead of
Leadhills contain

Oxide of lead - = - 70°50
Sulphuric acid - - - 25°75
Water of crystallization - 2°25

98°50

Analysis of the White Lead Ore of Leadhills.

The preceding sulphated lead ore erystallized tablets must
not be confounded with the white lead ore of the same
place; though it is crystallized also in hexaédral tablets, in
which the lead is found combined with carbonic and not
with sulphuric acid.

The specific gravity of this ore is 6480. It contains

Lead - ~ - - 77
Oxygen - ~ - 5
Carbonic acid - - - 16
Loss and water of crystallization 2

100

P4 Analysis

282 Extracts from the third Volume of

Analysis of the Native Antimony of Andreasterg.

Hitherto native antimony has been found in three places
only:

ist. In the silver mine of Sala and Weestmannland,
where Swab discovered it in a matrix of calcareous spar.

2d. In the mines of Challenges, near Allemont, in the
department of Isere. For the analysis of it we are indebted
to M. Sage.

3d. In the mine of Catherine Neufung, at Andreasberg,
in the Harz, where it is found in considerable masses.

It has the white colour of tin, inclining to leaden gray
It is compact, and has a great deal of metallic splendour.
On the fracture it is foliated. The fragments exhibit a grain
sometimes fine and sometimes coarse. It has a mean hard-
ness, and is soft to the touch. Its specific gravity is 6720.
The matrix of it is calcareous spar, quartz, &c.

It exhibits the same phenomena with the blowpipe as
regulus of antimony extracted from 1is ores. It fuses very
speedily into globules, and is dissipated in gray inodorous
fumes, which adhere to surrounding cold bodies, If the
metallic button be left to cool slowly, it 1s found to be co-
vered by and surrounded with white brilliant argentine crys~
tals. After total volatilization it leaves a small globule of
silver.

A hundred parts of native antimony of Andreasberg con-
tain
Antimony #®- - - 98

Silver - - | ‘ 1
Iron - - < ~ 0°25
99°29

It is probable that the silver is combined with it only
accidentally. .

Analysis of the Argentiferous Antimony of Andreasberg. :

This is one of the richest and oldest silver ores in that
country. It was formerly considered as arsenical silver,
which is found there also, but much more rarely.

M. Klaproth in his analysis employed a variety which
has been dug up for several years past. It is of a hard
grain, crystallized, and foliated on the fracture. By its
external characters, and the considerable quantity of silver
it contains, it approaches near to the antimoniated silver of
Altwolfach, in Furstemberg. Its specific gravity 1s 9820,

Exposed

the Analyses of M. Klaproth. 233

Exposed on charcoal to the blowpipe it requires a pretty
strong heat to be fused; the antimony is dissipated in fumes,
and leaves a button of pure silver.

Twenty-five grains of this ore, treated in a cupel with
four grains of lead, gave a button of silver weighing 19}
ppt iv de

A hundred parts, treated by the nitric and muriatic acids,
gave

‘Silver - - - a4
Antimony . - - 23
100

. Analysis of the Red Fibrous Ore of Antimony of Braunsdorf,

in Saxony.

The matrix of this ore is gray quartz; it is generally
found with ore of gray antimony, and some insulated crys-
tals of white antimony.

‘This ore has a beautiful mordoré and crimson colour, on
which account it has been called native mineral kermes. It
sometimes exhibits varied colours at its surface. It forms
small needly or capillary crystals, sometimes single, and
sometimes united in bundles: they have a silky splendour,
and are opake.

It is difficult to determine their specific gravity, on
account of the air-bubbles which are collected in the tufts
of the small capillary crystals, and which it is difficult to
expel. According to M. Klaproth it is 4090. This ore
contains

Antimony “ a ee, fhe.
Oxygen - = - - 10°80
Sulphur - - - - ,
Native kermes mineral differs then from gray sulphuret

of antimony only by the greater degree of the oxidation of
the antimony.

Analysis of the White Ore of Antimony of Przibrem, in

Bohemia.

This ore, lately discovered, is composed of crystals in
parallelopiped laminee. They are white, brilliant and radi-
ated at the surface. The largest are nine lines in length and
three in breadth. Strong compression is sufficient to make
them separate into small needles, which resemble those of

amianthus.

254. Extracts from the third Volume of

amianthus. They have, for matrix crystals of galena, to
which they slightly adhere.

They exhibit the same phenomena with the blowpipe as
white oxide of antimony precipitated by an aqueous solu-
tion of muriate of antimony; which is also susceptible of
crystallizing by rest, when slowly precipitated, by a small
quantity of water. - seasril

As this white oxide retains muriatic acid, M. Hacquet
presumed that this acid formed a-part also of the white ore
of antimony, But the analysis.of M, Klaproth proves that
this ore is a-pure oxide of antimony without muriatic acid.

Some crystals of this oxide are found also in very small ’

insulated tabletsin the red fibrous ore of antimony of Brauns-
dorf, in Saxony.

' Analysis of the Olive Ore of Cornwall,

The only ores of this arsenical copper, hitherto known,
are found in Cornwall, M. Klaproth, having obtained from
all the varieties of this ore the same results, except a few
slight differences in the proportions, gives here only an ana~
lysis of the Carrarac arsenical copper in needles.

This ore, when exposed to the flame of the blowpipe,
detonates. White arsenical fumes are disengaged from it ;
and it fuses mto a grayish red globule, which when fused
with borax gives‘a button of pure copper. Arsenical cop~
per contains

. Oxide of copper - - 50°62
Arsenic acids - = - 45

Water of crystallization ~ 93°50

99°12

The foliated olive ore crystallized, in beautiful hexaédral
tablets, of an emerald green colour, of Tincroft, near Red-
ruth, had before been considered as muriate of copner.
M. Klaproth, however, has found it to be composed, like
the preceding, of copper and arsenic acid. He had not a
sufficient quantity of it to determine exactly the proportions
of its principles.

It decrepitates speedily when heated on charcoal or in
a small] crucible, and flies off in small scales; which must
be ascribed not only to the lamellated texture of its crystals,
but also to the great quantity of the water of crystallization
% contains,

Arsenicat

o

the Analyses of M. Klaproth. 235

Arsenical Iron Ore.

This ore, which is exceedingly rare, is found also at Car-
rarac, in the county of Cornwall. M.Klaproth had only
one very small cubical crystal of it, with brilliant and po-
lished facets, of a meadow green colour, in a piece of cop-
per ore in quartz.

He does not indicate the proportions of its component
parts ; but he analysed a variety of this iron ore crystallized
in large cubes of an olivin green colour, extracted from a
newly opened pit, and found that it did not contain a single
atom of copper.

Analysis of the Ore of Muriate of Copper.

The combination of muriatic acid with copper, an-
nounced by Berthollet and Proust, in their analyses of the
green sand of Peru or of Acatamit, proves that muriatic,
acid is one of the mineralizing substances of this metal.

M. Proust has since given an analysis of the green copper
ore found at Los-Remollinos, in Chili, which is also com-

sed of muriate of copper. .

M. Klaproth repeated this analysis on a very large quan-
tity of this fossil, which is still rare. This ore, after being
reduced to powder, and freed by washing from the ochre
with which its crystalline texture was penetrated, had a
beautiful dark green colour.

Exposed to the blowpipe on charcoal, it communicated to
the flame a bright blue and green colour. The muriatic
acid is soon volatilized, and there remains on the charcoal
a button of pure copper.

If the ore be heated ina crucible it soon assumes a black
colour; but it gradually becomes greenish in the air. Jt
loses from six to seven per cent. when moderately heated ;
and from fifteen to eighteen when brought to a red heat.

Water boiled with a portion of pulverized ore, and then
filtered, passed without any colour; and a solution of ni-
trate of silver produced only a slight white precipitate,
which became black in the light. This proves that the
muriatic acid was not found in it in that proportion which
is poeesenty to be very soluble in water.

A hundred parts of this ore contain, according to
M. Klaproth, '

Oxide ofcopper - -— = 73

Muriatic aci - - antic 102

Water of cgystallization ‘° 16°9
' 100

And,

236 Extracts from the third Volume of

Amd, according to M. Proust,
Oxide of copper . ° 7624

Muriatic aci 3 = i 1032
Water * ~ - - 1939
¥eO

Fhese two analyses vary so little in. their proportions that
they serve to confirm each other. ;
Acatamit, according to Mr. Proust, contains

Oxide of copper . - 7049

Muriatic act - - - 1135

Water - - - - 18;°5
100

Analysis of the Ore of Phosphate of Copper.

Fhe natural combinations of phosphoric acid hitherto
Known are those of the phosphate of lime in apatite and
its varieties; and those of some species of phosphate of
lead, of phosphate of iron, and of ee ferruginous earth.

To these must be joined that of copper discovered in this
mew mineral, as 2 new species of copper ore.

It is found at Fimeberg, near Rheinbreidbach, on the
banks of the Rhine. Its green colour and its radiated tex-
ture made it be taken, at first, for a kind of malachite.

When exposed to the blewpipe on charcoal it fuses into
4 dark brown scoria, which at first assumes a round form}
but it soon divides and separates. After cooling it has a ,
dull metallic splendour, and a reddish gray colour.

4 hundred parts of this ore are composed of

Oxide of copper - = 68°13
Phosphoric acid 2 ¥ 30°95,
99°08

PITCH STONE.
Analysis of the Pitch Stone of Cyarsebach, near Meissen.

Under this name were formerly comprehended several
species of stones, which at present are placed more conve-
micntly among the semi-opals. ‘Fhis fossil is found in en-
tire masses of the moantains: it exhibits several varieties
of colour. There are some yellow, green, gray, reddish
brown, and blackish. It is compact, and in the inside has
the lustre of pitch. Its fracture.is conchoid. }ts substance
is penetrated by avery fine-veined tissue which binds it to-
gether, as may be distinctly seen by immersing the fossil in
water.

fis speeifie gravity is 1645, M. Klaproth, in his analy-

1

Bis,

the Analyses of M. Klaproth. 237

sis, employed the pitch stone of Meissen, which is pellucid
and yellow, inclining to olive green.
A hundred parts of this fossil contain

Silex x0 ist - 73
Alumine - - - 14°50
Lime - - - a
Oxide of iron - - 4
Oxide of manganese. - 0°10
Soda - > - - 75
Water = = - 8°50
9985

Analysis of the Pumice Stone of Lipari.

Fixed alkalies, in consequence of their solubility, had
long escaped the researches of chemists in the analysis of
stones. But as they are now known to exist in a number
of fossils, they ought always to be supposed to exist when
a sensible decrease is experienced in their decomposition.

This induced M. Klaproth to repeat the analysis of the
pumice stone of Lipari, in which he had observed a loss of
three per cent. These parts he found again in the seda
and potash, which enter, as constituent parts, into the
composition of this fossil. He obtained by nitric acid very
regular rhomboidal crystals of nitrate of soda; and, by the
addition of tartareous acid, crystallized grains of acidulous
tartrite of potash.

A hundred parts of the pumice stone of Lipari are com-
posed of

Silex - - - - - 77°50
Alumine - - - - 17°5@
Oxide of iron containing a little
manganese = - - - 1°75
Soda and potash - - ~ 3
99°75

Analysis of the Zirconia of Norway,

The diseoyery of this fossil, so valuable on account of
the elementary earth it contains, is the more interesting to
miineralogists, as this is the first time it has been found in
its matrix. We are not yet acquainted with ‘that of the
zirconia and hyacinth, which are stones of transportation.
The gangue from which it is extracted at Friedrichswarn is
a couipound of wed feld-spar and amphibolite, in which it

; As

938 Extracts from the third Volume of

is found interposed in an insulated state, in light brown
pellucid crystals.

The specific gravity of this zirconia is 4485.

It is perfectly infusible, and does not lose its colour by
calcination. It contams

Zirconia - - - 65
Silex - - - - 33
Oxide of iron - - t

n 99

Analysis of Madreporite.

Madreporite, belonging to the class of calcareous stones,
found by M. de Molle some years ago at Russbachthal, in
the country of Salzbourg, is a stone of transportation. Some,
specimens weigh from twenty to thirty pounds.

Externally it resembles basaltes so much that some mi-
neralogists considered it, at first, to be the same. Others
have believed that it was produced from madrepores. But
it exhibits no certain characters of a primitive organic for-
mation. Besides, it has such a great resemblance to the
real madreporites that it has thence borrowed its name. It
is of a gray colour: it is composed of divergent prisms,
brilliant on their transverse fracture, and of ‘a black and
duller colour en the longitudinal fracture. The fracture ex-
hibits a tissue of small bent lamine. It is entirely opake,
brittle, rough to the touch, and of moderate hardness.
The intervals between the bundles which compose it are in
part filled with small white leaves of calcareous spar.

According to the analysis of M. Molle, a hundred parts
of this madreporite contain

Lime - - 634;

Alumine - 307,

fra? OS MS eae

According to M. Klaproth,

Carbonate of lime —- - 93
Carbonate of magnesia - 0°50
Carbonate of iron = ~ - 1:25
Charcoal - - - - 0°50
Sandy silex - - - 4:50

An atom of oxide of manganese

Analysis

the Analyses of M. Klaproth. — 039

Analysis of Pharmacolite.

This fossil is found in the cobalt ore. of Wittichen,. in
Furstemberg, in. small white crystals, for the most part
capillary ; sometimes collected in tufts, sometimes united
in clusters, and rarely prismatic. They have a silky lustre.
They are sometimes covered with a red crust of cobalt,
M. Karsten has given an exact description of this new fos-
sil in his entieedosial tables.

The specific gravity of pharmacolite, in clusters, is 2640.

A hundred parts of pure pharmacolite, separated from
the cobalt and siliceous matrix with which it is accidentally
mixed, contain

Arsenic acid - - 50°54

Lime Se Metra ah, ob 25
Water - - - 24°46
100

Analysis of the Sand of Muska, near the River Aranyos ;
called Scorza by the Wallachians.

Among the interesting productions of Transylvania we
ought not to forget a sandy fossil, of a pistachio green
colour, inclining to tarin green, composed of small round
grains, entirely dull.’ It is found in small cavities of a
gray argillaceous stone of the valley of Muska. M. Muller,
who sent it to M. Klaproth, adds, that this sand, in regard
to its grain and colour, has a resembiance to several kinds
of gold ore. That grains of gold might easily be adulterated
by mixing it with them, if its specific gravity were not
much lighter: jt is 3135.

[t is mixed with white grains of quartz, so fine, though
visible, that it is not possible to separate them. This sand
contains

Silex - - - 43
Alumine - - ~ Q1
Lime - - - 14.
Oxide of iron - - 16°50
Oxide of manganese — + 0°25
Loss by calcination —- 2°50
97°25

Analysis

£40 Extracts from the third Volume of
Analysis of the Fibrous Brown Sulphate of Baryies.

The fossil of Neu-Leiningen, in the Palatinate, con-
founded with calamine, seemed worthy of being analysed ;
and it now appears to be a sulphate of barytes, and not an
oxide of zinc. Its external characters, so different from
those of the other species of the sulphate of barytes, ought
to: make it be considered as a particular species.

The description given of it by M. Karsten is as follows :

Fibrous sulphate of barytes is of a chestnut brown colour
on the fracture, when fresh.

Its form holds a mean between that in rognons and that
in.clusters.. Its surface and lustre cannot be determined,
because the fossil seems to: have been exposed to friction.

Internally it is not-very brilliant. It has a greasy aspect.

Its fracture is fibrous; and the fibres diverge like the
beards of a quill.

The fragments are irregularly angular, and the edges are
pellucid.

It is soft and heavy: its specific gravity is 4080.

Three hundred grains of this pure sulphate of barytes,
the lime adhering to which had been separated by acetous
acid, pounded, and boiled with 600 grains of the carbonate
of potash, decomposed and redissolved in muriatic acid,
erystallized in tablets of muriate of barytes. ’

When redissolved in water and remixed with the first
solution of potash, which contained the sulphuric acid of
the decomposed fossil, and in which the excess of potash
had been saturated by acetous acid, the sulphate of barytes
was precipitated. When washed and collected it weighed
297 grains.

A solution of prussiate of potash, poured into the water
of the washing, gave a slight indication of iron,

Analysis of the Manganese Ore of Sleseld, in the Harz.

This ore, which has for matrix a white sulphate of
barytes, is distinguished from other ores of manganese by
a greater metallic splendour, and by the size of its pris-
matic crystals with four planes, which are sometimes more
than two inches in length. Jt was formerly believed that .
this metallic splendour arose frum a considerable quantity
of tron; but the analysis of M. Klaproth has proved that
it contains. none of that metal.

A hun-

the Analyses of M. Klaproth: 241

A hundred parts of his ore are composed of
Blue oxide of manganese, at the maximum of

oxidation it can retain in the fire, - — 90°50

Water ~ - = = - - 7
Oxygen 44 cubic inches, or in weight - 2°95
99°75

This small quantity of oxygen in excess announces tha
this ore is of no value for the purpose of extracting éxygen
gas from it, or for preparing oxygenated muriatic acid.

The seven per cent. of water constantly found in several
analyses is too large a quantity to be interposed only hy-
groscopically in the mineral: It ought certainly to be con-
sidered as the water of crystallization of that ore.

. Anatysis of the Manganese of Moravia.

This ore is of a steel gray colour on the fracture when
fresh: it hes a metallic lustre: It is composed of short
needles united in bundles, or diverging from a common
centre, and forming a compact mass.

A hundred parts of the manganese of Moravia contain

Black oxide of manganese, at the maximum of

oxidation it can retain in the fire, - - 89
Water - - - - - _- 0°50
Oxygen 201 cubic inches, or inweight == 10°25

99°75

The gray radiated ores of manganese are those, there-
fore, which furnish the greatest abundance of oxygen.

Analysis of the black earthy Ore of Manganese.

This ore of the Harz is found in the fissures of the rocks,
» like soft mud. But it soon dries in the air, and is con-
verted into fine black dust.

A hundred parts of it contain

Brown oxide of manganese « 68
Oxide of iron - - - = 6°50
Charcoal - - - - 1
Barytes - ~ - - - 1
Silex BS < - - - 48
Water <- = ~ - - 17°50
102

VoL. XVII. No. 67. Q The

g4¢ = Extracts from the Analyses of M. Klaproih.

The excess in the sum of the products of the analysis
arises in al] probability from the oxide of manganese having
absorbed, during the calcination, a greater quantity of oxy-
gen than it contained in the fossil. Nature employs this —
muddy manganese to delineate and colour those dendrites,
often so beautiful, which are found in calcareous stones,
in marly schists, and in the meagre kinds of quartz. The
water of the mountains, charged with oxide of manganese,
attracted by the veins and cracks of the stone, as by capil-
Jary tubes, deposits it on evaporating in all the ramifications
through which it has passed.

Analysis of the Asphaltum of Altania.

The asphaltum or bitumen found in thick strata near
Avlona, in Albania, is of a blackish gray colour. This
fossil is compact without transparence, of a moderate lustre
on the surface as well as on the fracture, and of a greasy
polish. When scratched the traces are dull; its fracture
is imperfectly conchoid, and the edges and fragments are
acute.

It is light and somewhat greasy and soft to the touch.
Its specific gravity is 1205. ;

It burns with a bright and brilliant flame; and it is be-
lieved that it formerly entered into the composition of the
Greek fire.

Asphaltum is soluble only in oils and in ether. It dis-
solves very well in rectified oil of petroleum. Five parts of
this oil dissolved without heat one part of asphaltum in 24
hours. The saturated solution had a brown colour. When
evaporated in a gentle heat it deposited the asphaltum, °
under the form of a blackish brown brilliant varnish. As-
phaltum dissolved also very well in sulphuric ether, and the
solution had a reddish brown colour. The ether deposited
by evaporation the bitumen, inspissated under the form of
a reddish brown extract. Alcohol cannot redissolve the

Acids and caustic alkaline solutions, even concentrated.
and in a state of ebullition, cannot dissolve it properly.

A hundred grains of asphaltum of Avlona analysed in
the dry way, distilled and calcined, are composed of
36 cubic inches of hydrogen gas
32 grains of bituminous oil

6 of water faintly ammoniacal
30. grains of charcoal
7+ of silex
74 of alumine
¢ of lime
Ji oxide

Red coloured Water of a Lake in South Prussia. 243

14 oxide of iron
4 oxide of manganese.

Analysis of the Pearl-stone of Hungary.

The mountains of Tekelbart in Hungary, from which so
many rare fossils are extracted, among which are the beau-
tiful changing opals, furnish that also which Werner has
classed in the system next to Pitch-stone, under the name
of Pearl-stone.

That which M. Klaproth subjected to analysis is of an
ash gray colour, traversed by yellow bands. It is found
between Kerestur and Tokai, in alternate strata separated
by others of argillaceous porphyry.

The specific gravity of this fossil is 2340. It swells up
by the blowpipe like zeolite; but it does not fuse into a
globule. z

A piece calcined for two hours in a moderate fire lost
nothing of its form. Its colour had become reddish brown.
It had experienced 44 per cent. loss. ;

Pearl-stone was completely vitrified in a porcelain fur-
nace in a clay crucible, as well as in a crucible lined with
charcoal.

A hundred parts of the pearl-stone of Hungary, treated
successively by soda and by acids, gave in their analysis:

Silex - - - 75°25
Alumine - > - 12g
Oxide of iron - - 1:60
Lime - - - 0°50
Potash - ~ - 4°50
Water * - - 4°50
98°35

[To be continued. }

XLI. Examination of the Red coloured Water of a Lake near
Lubotin, in South Prussia. By Professor KuapkoTu*.

ae South Prussian gazette of the 8th of February 1800,
and the Berlin gazette of the 13th, gaye an account of a
phenomenon

* From Scherer’s Al/zemeines Yournal der Chemie, No- 33.—About
twenty years ago Mr. Achard examined water tinged in a similar manner,
which he obtained from a lake near Strautzberg. In the month of Decem-
ber, 1737, the ice of this lake was coloured red, and continued so «Il the

Qi month

2: Examination of the Red coloured Water

phenomenon observed in the water of a lake near the vil-
Jage of Lubotin, in the department. of Poren in Soutl:
Prussia. The*most remarkable particulars of which were
as follows:

The water of this lake had appeared for some time to be
covered with red spots, like dreps of blood: in other places
of considerable extent it was of a violet red colour; in
others of a grass green colour, and large masses of a red
matter floated on the surface of it. When the lake im
eonsequence of the severe cold became frozen, the ice for
three lines in thickness was of the same red, blue, and
green colour which the water had exhibited. The lower
part of the ice, however, was uncoloured : a green and red
matter inclining to blue was found below the ice to the
thickness of a quarter of a yard.

A manuscript account of the same phenomenon gives
the following account:—-Aboat the mmddle of December
the fishermen, en breaking up the ice in order to fish, ob-
served that not only the ice but ‘also the water of the lake
was coloured red, blue, and green, in two places. The
lake is about a quarter of a mile in length, four hundred
paces in breadth, and is completely surrounded by moun
tains.

A wood stands close to the margin of the lake on one
side, and on the other lies the village of Lubotin with its
surrounding district: an arm of the lake, about a hundred

feet in lencth and a few paces in breadth, extends to the
village. In this arm, and for a certain extent on both
banks of the lake, the water was colouted to half an ell in
depth ; but under this coloured stratum the water was in its
usual state. Fhe case was the same in a part at the ex-
tremity of the lake, about fifty feet in length and twelve or
thirteen feet in breadth. The water in the remaining part:
of the lake was colourless. The ice which covered these
_ places was marbled with green, blue, and red spots, of
from one to two feet in length. The lower part of the ice,
-like the water below it, had no unusual colour.

Both these accounts coincide in regard to the principal

points of the phenomenon; the small deviations arise no

month of March, when it appeared to be gecen. In the latter state the
“water could be used for painting.” The fea water, after it had stood for
some time, deposited a red insipid matter, which, when viewed by the
microscope, seemed to be composed of threads interwoven with eah
other. Mr. Achird concluded, from the few experiments he mede with
it, that the colouring matter was a vegetable substance, See his Cy-
misch Phy sische Schiifien, Beitia 1780, P- 251—253-

doubt

of a Lake near Lubotin, in South Prussia. 245

doubt from the observations having been made at different
times.

It may readily be believed that superstition, as usual, con-
verted this natural phenomenon into a wonderful prodigy,
which was considered as the consequence of a shower of
blood, and the forerunner of varions misfortunes.

To the enlightened philosopher, however, such phzeno-
mena are of importance, as they aiford him means of ex-
plaining, on true principles, what few men of science have
made an object of their research.

It needs, therefore, excite no wonder that different opi-
nions have been entertained in regard to the nature and
cause of this phenomenon. Some ascribed it to mineral
substances, and thence deduced proofs of the existence of
veins of ore concealed in the neighbourhood. Others con-
ceived that it had some connection with the earthquake
which had a little before been experienced in several parts
of Silesia and Bohemia. But, by the help of chemistry,
this phenomenon has been found susceptible of another
explanation much simpler,

Various authors, both antient and modern, speak of
water being coloured and altered in its appearance. We,
are told by Pliny* that the water of the lakes near Babylon
had a red colour for cleven days in summer, and that the
Borysthenes, now called the Dnieper, was in summer of a
blue colour. In 1668 Mr. Smith+ found the water of the
Mediterranean to be of a sky blue colour, and when the
sun shone upon it this colour was changed to red or purple.
The missionary Ferdinand Consag f, in the year 1746, ob-
served in the open sea, near California, that the water for
the extent of half a mile was of a bluish red colour, Nayi-
gators have often seen the water at the mouth of the river
Plata, on the coast of South America, of a blood. red
colour. Schooten found the water at Cape Desiré coloured.
red, in consequence of ‘a sea unicorn (Monodun Monocerss),
having lost its horn. ,

Water is sometimes coloured red, not in reality, but ap-
parently by aquatic insects, which at certain seasons cover
the surface of ditches and ponds. ‘

The present case, however, is different. The coloured
water of the Jake near Lubotin, a considerable quantity of
which was sent to Berlin for chemical cxamination, excited
great attention when first seen, by its agreeable change-,

* Vist. Nar, lib. xxxi. cap. 70. + Acta Erudit. 1709.
t Hust. de Californie, tom. iii. Paris 1767.
O38 ableness

246 Examination of the Red coloured Water

ableness of colour. When viewed in a vessel of white glass
and turned from the light, it appeared of a dark red colour,
inclining to crimson, which rendered it entirely opake; but
the froth with which it became covered on being strongly
shaken was of a bright blue colour. When the glass was
turned towards the light the redness vanished, and the
water appeared of a sky blue colour. This change of colour
took place for several days when the water was preserved
in a close vessel.

The results of the different researches made in regard to
this phenomenon were as follows :

Ist. White paper which had been immersed in this water
appeared, after being dried, of a blue colour. The colour
suffered no perceptible change either from diluted acids of
from alkaline salts.

2d. When poured into a porcelain saucer the water ap-
peared red in the middle and blue at the edges. When
placed on warm sand indigo-blue rings were deposited on
the sides of the vessel during the evaporation: the last por-
tion, however, was dried into a dirty blueish green mass.
When put into water it was not redissolved, but merely
divided into blackish scales. The water was again eva-
porated and digested, but the flakes still remained insoluble.

3d. Another part of the water was put into a glass vessel
closed only slightly and deposited in a warm place. The
water soon lost its colour, assumed a cascous appearance,
and deposited tender blueish green flakes, which were col-
lected and dried. When put on ardent coals, or held to
the flame on the point of a knife, they puffed up and burned,
emitting the smell of burnt animal substances.

4th. When mixed with alcohol the mixture gradually
became turbid, and slimy blueish flakes were separated.

5th. By the addition of sulphuric acid the water, as soon
as the first drop of acid tell into it, lost the property of be-
¢oming red even when turned from the light, and ap-
peared when held in every direction of a bright blue colour.

When exposed to heat, the water at first appeared of a light,

green colour; it then became completely coloured, and
tender woolly thready flakes of a blue colour were deposited.
6th. When decomposed with sulphuric acid the colour
6f the water first became of a bright grass green colour,
then of a Jemon, and at last of a straw colour. The tender

woolly flakes were of a dirty grayish green colour.
7th. When the water was decomposed with pure nitric
acid it appeared throughout of a sky blue colour. When
exposed to heat all the colour disappcared, the water ci
only

of a Lake near Lubotin, in South Prussia. 947

anly became perfectly clear and colourless, but the caseous
flakes which were separated appeared of a pale whitish
yellow.

8th. Oxygenated muriatic acid destroyed the colour com<
pletely in the course of a few seconds. The water remained
for some time turbid and whitish: when exposed to heat it
suffered yellowish flakes to be deposited.

gth. By caustic alkali the colour of the water immes,
diately became brownish. A few gray flakes were deposited;
the greater part of which, however, were afterwards dis-
solved. When the clear solution was neutralized by mu-
riatic acid, the part dissolved in the alkali was again sepa-
rated in soft yellowish gray flakes.

These results are sufficient to enable chemists to deter
mine with certainty the nature of the matter contained in
this water. It consists of those cemponent parts com-
monly comprehended under the name of the albuminous
principle, and which in the present case served as the basis
of a peculiar colouring matter of the nature of indigo. This
vegetable albumen which is contained in a great many
plants, and to which belong those component parts of ve-
getables known under the names of gluten, materia vegeto~
animalis, &c., is, in regard to its component parts and
chemical properties, of an animal nature, and has a near
affinity to animal albumen, the caseous parts of milk, and
the curdled part of serum. If those plants which among
their intimate component parts contain this albuminous
matter are abundant at the same time in colouring matter,
the latter is commonly in close union with the former. We
have an example of this in indigo, the basis of which is of
the same nature as albumen.

The dispersion in water of this colouring matter, com=
bined with albumen, can take place only at periods when
the plants, to the component parts of which it belongs,
are in a state of solution and decomposition by desiccation
or putrefaction. The phenomenon, therefore, cannot be
observed in snmmer, when the plants are alive and in a
state of vegetation, but only in winter, when they are
dead. By the successive decomposition of the dead plants
under the water, the extractive matter, and such of its com-
ponent parts as are susceptible of complete solution in that
fluid, pass into it, The albumen is at first received by the
water, but it does not enter into a constant, but only ap-
parent and mechanical, solution; the particles exercise a
mutual attraction, approach each other, and in that state
form a flaky accumulation which floats on the water fs

Q4 ey

248 * Examination of the Red coloured Water

they at length are converted into a sort of slime. The
colouring matter combined with the albumen undergoes
also essential changes, till, being gradually overloaded with
oxygen, it is entirely decomposed. When left to itself in
stagnant water this disappearance of the colouring matter,
takes place only very slowly. The coloration of the water
by it may therefore, especially in winter, continue several
weeks. On the other hand, when aq speedier saturation
with oxygen is effected the colour is immediately decom -
posed, as is the case when the coloured water is decom-

posed by nitrous acid or oxygenated muriatic acid. t
Nothing further, therefore, seems necessary to explain
this phenomenon than a botanical determination of those
plants which after their death transmit these component
arts to water. This task, however, I must leave ta
hoe who may have an opportunity of making such
researches on the spot. But I must here observe, that a
season of the year in which one can hope to find these
plants in their living state ought to be chosen for this
purpose. 5
From various grounds, however, it appears to me pro-
bable that these plants belong to the order of the crypto-
gamia aquatic plants, and are perhaps of the species of the
Conferva tremella, Ulva, &c. Albumen seems to form a
principal component part in these plants, because ‘on their
decomposition in the dry way, besides the usual products,
they give also ammonia. It might therefore he af import-
ance to examine whether this colouring matter, which ma-
nifests itself by the natural decomposition of the plant,
could be extracted from it iminediately by artificial means.
f am inclined to think that this matter will be found in the
Ulua pruniformis, Linn., because this singular plant, at
the end of its vegetable lite, is converted into a gelatinous
substance, and in that state, before its total solution, floats
for some time on the surface of the water. The pheeno-
mena I observed in my experiments on this coloured water
exhibited a chemical analogy to those of the colouring
matter obtained from the indigo plant, Indigofera tincto-
rid Ind. argentia; Ind. disperma} and from woad, Isatis
tinetoria. For though the water appeared of a dark red
crimson colour, this colour was merely an optical illusion,
occasioned by the refraction of the rays of light. The real
colour was a pure blue. This property of indigo matter to
assume an apparent red colour I have observed in the
solid colouring matter itself, as the best sort of the West
‘Indian indign, as well as that extracted from woad, ex-
x. “hibits

of a Lake near Lubotin, in South Prussia. 246

hibits on its smooth surface, when exposed to the light, a
cupreous colour. The phenomenon also observed in re-
gard to indigo, that when strewed over coals the smoke
which rises immediately from it, when viewed against the
light, has a beautiful light red colour, may be connected
with the same causes.

This phenomenon is not so uncommon as seems generally
to be believed. A few years ago I had an opportunity of making
similar experiments on water found in a lake at Strautzberg,
not far from Berlin. The same circumstances were observed
here, and in the same season, namely, the winter, The
water of the lake was in some places coloured red, blue, and

reen; and masses of the same colours floated about in the
parts of the water which were colourless, In flasks which
were filled with the water and transmitted to me, the co~-
Joured part of the water gradually separated itself and as-
cended, while the water at the bottom remained colourless,
The phenomena which took place in the course of my ex~
periments were exactly similar to those which occurred in
my researches respecting that of the Jake near Lubotin. In
January 1799 Mr. Achard had an opportunity to subject
the water of this lake, supposed to be converted into blood,
to some experiments also, from which he concluded that
the colouring matter consisted of some vegetable substance,
and floated in the water but was not properly dissolved in
it. The small quantity which he had obtained of this water.
did not permit him to make any further experiments of a
more decisive nature. ;

A similar phenomenon had been before observed several
times in the lake near Strautzberg. According to an ac~
count published by Mr. Campe, a clergyman at Alt-Lands-
berg, in the Physicalischen Belustigungen*, he saw in the,
year 1737 the water of that arm of the lake which proceeds
towards the town entirely of a red colour. Fifteen years
after, the lake in the same place appeared to be wholly
sreen. In the course of two days the water had resumed
its usual colour. The water put into flasks, which at first
was somewhat red, gradually became putrid; soon after it
was thick and muddy ;. and at the end of some wecks there
was separated from it a dark red mass which floated on the
surface. In the present case it appeared of two colours ;:
when turned from the light, opake and dark red; when
turned towards the light, dark green. This green colour
observed by Campe is, however, not essentially different

* Part xi. Berlin 1752.
from

250 Explanation of the Inscription on @ Brick

from the blue colour of the water which I examitied: it
only shows that the proportion of the oxygen combined
with the colouring matter was less. For when that quantity
of oxygen, which converted the original green colour of the
water of the lake of Lubotin into blue, was extracted by
means of bodies which had a greater affinity for oxygen,
the green colour returned; as was the case when the water
was decomposed with sulphuric acid, or with a solution of
tin in mumiatic acid.

A similar return of blue to green is observed in indigo:
wthen employed in the art of dyeing. To prepare it for
that purpose it must be decomposed with such substances
as deprive it of a part of its oxygen. The prepared indigo
liquor appears then green, and the cloth dipped in it 1s
taken out green. But while the cloth is spread out in the
air the pigment has an opportunity of acquiring that oxy-
gen which it lost in the bath, by which means the blue co-
Jour is produced and fixed.

This coincidence in regard to the phenomena observed
in the water of the lake of Lubotin with those of indigo,
affords a further proof that the colouring matter of that
water was of a nature analogous to indigo. .

ee

XLU. Explanation of the Inscription on a Brick from the
Site of antient Babylon. By the Rev. SAMuEL HEN-
ey, M.A. P.AS*

Ox the face of Dr. Hulme’s brick, over two rude figures
of a larse dog, barking, and the head of a water-bird, is
the following inscription :

vee eG
which, expressed in Hebrew characters, distinctly exhibits
the words js 72, and literally signifies, A BRICK BAKED
BY THE SUN.

That «§ $= ¢ 12y, in its primary sense, placenta cocta
(Simonis Lexicon, by Eichhorn) is @ baked brick, it is pre-
sumed no one will question; any more than that Q 4 js;
signifies the suz; when the ground for so rendering it is
given.

That j8 was the name of an antient city in Egypt, styled

* From Archeologia, or Miscellaneous Tracts relating to Antiquity,
by the Society of Autiquarics,—just published. 3
1 in

from the Site of dntient Babylon. O51

fa Greek “Haseroai, the version of the LXX will prove:
QN, 7 es ‘“HAemons. (Exod. 1. 2.) This city was built on
4 considerable hill in honour of the sun, (Strabo, lib. xvi.
p- 1155,) who had there also a celebrated temple. Remains
Of these are still extant on their original site, now named
Matarea, two hours N.N.E. of Cairo, consisting, as Shaw,
Niebuhr, and later travellers relate, of a sphinx, obelisk,
and fragments of marble, granite, &c. ‘This temple is
mentioned, not only by Strabo, but Herodotus, who also
records, that an annual assembly was holden in it in honour
of the presiding divinity (lib. li. § 59). OF the city and’
its sacred monuments, the destruction by the king of Ba-
bylon, Nebuchadnezzar, Jeremiah expressly foretold, (xhii.
s—13):—Hle shall break also the images of Beth-shemesh,
(or, the temple of the Sun) that is m the land of Egypt.
Now, that Heliopolis received its original name from the
Sun is indisputable, inasmuch as that, in antient Egypt,
he was denominated ON. This is evident from Jablonski
(Panth. Egypt. I. 137), Georgi (Alphabet. Tibetan. p. 87),
and expressly from Cyril (in Hoseam, p- 145) who, on
reciting the Egyptian fable which makes Apis the son of
the Moon and offspring of the Sun, adds, ‘¢ that the Sun
was called ON by the Egyptians :?—ON de esi nar’ avrag
‘O ‘HAIOS, in perfect analogy with the Coptic oer, which,
in the language of Upper Egypt, signified LIGHT, and the
Arabic oo Cas the eye or fountain of light.

In perfect accordance with the inscription are the hicro-
glyphical figures on the brick. That Sreius, the chiet of
the stars, was symbolized by a Doc, a thousand monu-
ments will evince, independently of the name Agleoxuuy, OT
Dog-star, which to this day he retains. The origin and
application of this symbol are in themselves sufhciently

lain. The vigilance of a dog was significantly expressive
of the star, which, by its heliacal appearance, gave certain
notice that the sun had arrived at its greatest elevation.
Hence the Larrator Anusts in Egypt, which, according
to the rabbins, was the same with Nigcuaz, the barking
watch-dog of the Av1TEs. In 2 Kings, xvil. 24, we read
that ‘ the king of Assyria brought from Babylon, Cutha,
Ava, and other cities, colonies to repeople the empty cities
of Samaria, whose inhabitants this conqueror had carried
away captive.” In verse 31 it is added that, as these na-
tions, in their new settlements, sct up their gods, so the
gods of the Avites were Nilchaz and Tartak. The precise
forma of the latter is hitherto unascertained ; but comumenta~
tors

252 Explanation of the Inscription on a Brick

tors explain it to have denoted, the stated revolution of the
Sun; which perfectly agrees with the import of Nibchax,
literally signitying the barking watch-dog. (1023 from Tn
to watch, and 23 to Lark as a dog. Kimchi.) Thus, Abar-
banel: mya nine s5957 ww ins wy tonym, and the
Avites made Nibchaz, by which is intimated THE Doce
YHAT LOUDLY BARKS. Accordingly, about three hours
from Berytus, towards Tripoli, the country these Avites
occupied, is a high mountain, upon which was erected, on
a column, a vast dog, which uniformly barked at the sea-
son. Thongh this monument be now overthrown, its re-
mains are still visible in the neighbouring sea; whilst a
river, that empties itself in it, still keeps the name of the

river of THE Doc, lea | ez ,2927%3. This river the

Greeks and Latins styled Lycus, from the resemblance, as
is conjectured, to those that sailed by, which the dog’ on
the column might have born to a wolf (Eichhorn’s Si-
monis, p. 965) ; but rather, as is probable, from both hav-
ing a corgruity in their hieroglyphic application; the wolf
being sacred to the sun, as an animal of the dawn. Hence
the wolf in the temple of Apollo at Delphi, and the epithet
Lycian, ascribed to the same god; not to omit thatthe
term ATKABA® for a year, properly expresses an anniver~
sary procession of light.

Nor, so far as Egyptian hieroglyphigs will go, is there any
discrepancy in respect to the Brrp. The rjse of the dog-
star, or barking of Anubis, statedly proclaimed the oyer-
flow of the Nile; a constant concomitant of which was the
{pis. This bird, as such, is frequently seen on Egyptian
coins; and, to express its relation to the Nile, with fwo
lotus leaves on its head; which were the established cha-
racteristics on the head of that river when personified at the
time of exundation: on the Nilometer also the same leaves
appear floating upon the high-water line. Now, as to the
like overflow with the Nile the Euphrates is annually sub-
ject, it is more than probable that Babylonia might have
owed its deliverance from noxious reptiles to the same, or
some similar bird. If so, the divine honours vouchsafed
to the Idis in Egypt for its anniversary good offices would
afford at Babylon a sufficient reason for introducing the lird
at this season, along with the darking dog, discriminative
of it.

The inscription itself is in two views pertinent. This
brick is unquestionably swn-laked, and therefore exhibited
an effect of the intense power of the great “ Ava a Hed

; ut

from the Site of antient Babylon. 25%

but it had, perhaps, still greater pertinence, as, in that part
of the structure which bricks with this impress were de-
signed to occupy, each one might serve to commence a
new series in the annual order of astronomical records,
which the entire pillar, or obelisk, might be destined to
preserve. In Egypt, we know, one name of the dog-stur
was SETH, and that the most antient and wise of the
Evyptian astronomers dated the commencement of their
year from his heliacal rise (Jablonski, If. 51). How far
this name extended, it is not easy to define: but Josephus
mentions a tradition of the existence of two brick pillars of
Seth, one of them swn-laked, which contained astronomical
records antecedent to the flood. The true history of this
might be, that on them were inscribed a relative register of
solar, Junar, and sideral revolutions, adjusted to the series
of antediluvian years. The Egyptians, hgwever, dated the
origin of the world from the first rise of the dog star, and
4 notion not unlike it occurs in the sublime poem of Job,
who bordered on the confines of Chaldea, (chap. xxxviil.)

Where wert thou when I laid the foundations of the earth *
. Whereupon were the sockets thereof set ?

Or who laid the corner stone of the same ?

When the morning stars sang together,

And all the sons of God shouted for joy.

Though it were to a far less remote period that the astro-
nomical observations extended, which were recorded on
bricks at Babylon, and thence transmitted by Callisthenes
to Aristotle, they, however, fix the first foundation of that
city to the time of Nimrod, and most accurately agree with
its history by Moses.

But here a consideration arises of no little importance.
The inscriptions on the two sides of this brick essentially
differ, the one being of alphabetic characters, the other
monogrammic. Alphabetic characters of the same form
may be seen, in frequent recurrence, upon both Egyptian
and Pheenician remains; yet, as far as 1 can discover, are
visible on no other of these bricks; whilst the monogram-
mi¢ occur on them all. Dr. Hacer, who hath written on
the Babylonian inscriptions with much erudition and acute-
ness, passes this topic unnoticed. By comparing, never-
theless, the bricks engraved in his work *, it will be seen,
from the order in which particular characters recur, that
sufficient scope is left to suppose the inscriptions of which

* For an account of Dr. Hager’s work, sce Puailosophical Magazine,

vol. xi.
they

254 Eleventh Communication from Dr. Thornton.

they consist are rather NOTATIONS than NARRATIVES. Nor
do [ apprehend any evidence from the ruins of Persepolis,
or the Persepolitan monument, I send herewith*, will mi-
htate in the least against this conjecture. The figures Dr.
Hacer has given from the cylinders, appear to indicate
festivals corresponding with the astronomical notices that
accompany them; and the goat of the second may havea
relative import with that in this present from M. Miu.

XLIII. Eleventh Communication from Dr, THORNTON,
To Mr. Tilloch.

No. 1, Hinde-street, Manchester-square,
SIR, December 20, 1803.

Tx the last letter that I had the honour of addressing to the
philosophic world, through the medium of your excellent
Magazine, I Penianen among my observations the con-
sideration of the Lalance of principles as affecting health,
and even the very existence of the animal ceconomy. The
following cases will further tend to illustrate this opinion :

Case of Mrs. Chapman.

Mrs. Chapman, et. 65, a nurse employed in the first
families, being upon a visit to the housekeeper, upon her
coming to town, at the dowager lady Williams Wynne, was
ordered by me thirty drops of laudanum, and an aperient
draught in the morning, to prevent the constipating effects
of laudanum. She took the same, and passed a very com-
fortable night. In the morning the maid servant came to
give her the morning draught; but, by mistake, took up
the bottle containing the laudanum, ‘which she poured out,
and the whole was drunk down, amounting to near two
ounces. Some little time elapsed before the mistake was
discovered, and I was immediately sent for. I ordered an
emetic, and lemonade to be drunk plentifully, and the pa-
tient to be got up, and to be continually roused to take the
acid drink. By this means there was “only a sensation of
great drowsiness produced by the opium, and the patient
being at length allowed to sleep, this went off, and she was
as well as ever in the evening.

* An engraving forwarded to Mr. Henley by M. Millin, superin-
tendant of the National Museum at Paris. It exhibits the face of the
celebrated Perscpolitan monument brought lately to France by M. Mi-
chiux,

Case

Eleventh Communication from Dr. Thornton. 245

Case of Mrs. .
When called to this lady, I found her stupified on the

bed, with an unconquerable disposition to fall asleep in
whatever position placed. She was six months gone with
child; At} from some disagreement with her husband, who
had left her, she conceived the wretched project of ridding
herself of an existence now become insupportable without
that relief which religion affords, and which ever deters from
suicide in the hour of affliction. As prior help had been
called in, and the emetic sent had operated, I ordered upon
my arrival vinegar mixed with water to be drank, which
awakened our torpid patient, and being repeated at intervals,
until the lemonade was substituted, took off the sedative
powers of laudanum; and in the evening our patient was
free from all danger.

Observations on these Cases by Dr. Thornton.

1. Laudanum and wine have been happily compared by
modern physicians as to their effects on the animal ceco-
nomy.

2. As wine by distillation is made into brandy, and
brandy, by another process, into ether, so do we explain
the concentrated powers of laudanum dependent upon a few
drops.

3. As there is first ill-directed action, then total loss of
muscular power, and sleep, the kind provision of nature to
recruit the irritable principle, taken away by the disoxygen-
ating effect of too much wine or laudanum received into
the stomach, the philosophic practice indicated is to add as
a balance to the hydrogen the oxygenous principle,

4. That this last principle is greedily absorbed by the
stomach under these conditions appears from the acid
drinks being at first brought up free of the acid taste, and
removing quickly the intoxication.

5. In the case of sir George Braithwaite Boughton, bart.
(Vide my Philosophy of Medicine, vol. iv. p. 128), where,
in addition to the lemonade, the inhalation of a superoxy-
genated air was employed, the cure was remarkably rapid.

6. In the West Indies, when the negro has put out the
quantity of rum, he says to his master, ‘¢ Masse, do you
drinky for drunky, or drinky for dry ;” and proportions the
quantity of lime-juice accordingly, employing no difference
as to the spirits or water. i

7. The disagreeable effects of landanum on the head, as
with intoxication, the next day, is remoyed by the mesa

Q

256 Contribution towards the assaying of Coins:

of vital air. (Vide my Philosopliy of Medicine, case xxxiy/
vol. i. p. 497.) This observation is worthy of regard to
such as are obliged to have recourse to this remed; »as3
solace during night, labouring under irremediable diséase.

8. The sudden death produced by drinking of leriionade,
when hot by dancing, shows that the oxygen is hastily ab-
sorbed; and no such effect being produced, if a little spirit
be added, is a further proof how these principles (viz. by-
drogen and oxygen) balance each other.

9. The practice of taking persons out who ate swoon-
ing,.Or in a state of intoxication, into the open air fot
their'yecovery, deperids upon the supply of oxygen to the
system, then deficient.

Sir, I have been more anxious to record such cases, as
the accidents by opium are much more frequent than from
any other means. In the one case above recorded, the lady
went to.different shops and got a small supply from each,
and then drank off the aggregate. Other poisons are not
easily procured. I shall conclude in the memorable words
of sir George Brathwaite Boughton * :—TJf it can be of any
use in a science which has for its olject, the ease and happi-
ness of mankind, I shall always look back with pleasure ta.
these accidents which have afforded me an opportunity of
giving you this detail.”

I am, sir, your obedient servant,
RoBert JOHN THORNTON:

[My next communication, will be the case of a physician
cured by the inhalation of vital air, every other means hav-
ing previously failed.]

XLIV. 4 Contribution towards the assaying of Coins. By
Professor KLAPROTH.

Iw this essay I shall first give an account of the process I
employed: I shall then exhibit the component parts of the’
coins I examined, and conclude with some observations de=
duced from my experiments.

I found by some previous experiments that on the earlier
Greek coins, besides copper, the principal component part,
I,had to direct my attention to tin and lead as essential ad-
ditions, and to iron and silver as accidental mixtures; and
in the Roman coins to a considerable quantity of zinc. In

/

# Ina letter written’ to'and published by Dr. Beddoes,
con-

Contribution towards the assaying of Coins. 257

consequence of these observations I made my docimastic
researclies in the following manner :

Ist. After freeing the coin from its rust, the erugo nolilis,
I poured over it in a phial moderately strong nitric acid, and
left it to spontaneous solution. Next day I poured the so-
lution from the remaining part of the coin, and, having
supplied its place by a new quantity of acid, repeated the
Same process till the coin was completely dissolved. :

If it contained tin, which was the case with all the Greek
coins, but only with some of the Roman, it remained be-
hind in the form of a grayish white calx, and was collected
on filtering paper. In regard to Roman coins which con-
tained no tin, its absence was indicated by the perfect clear-
ness of the nitric solution. A counter-experiment, in which
T employed a mixture of copper with a quantity of tin ex-
actly weighed, showed that 100 parts of the above calx of
tin might be estimated as equal to 714 parts of metallic tin.
In order that I might convert the calx of tin separated from
the coin into a metallic form, I boiled it with a quantity of
muriatic acid sufficient for its solution, diluted the solution
with two parts of water, and immersed in it a rod of zinc,
by which means the metallic tin was precipitated.

But when the solution of copper containing tin was de-
composed by nitric acid, the ¢alx of tin was by these means
combined with a greater proportion of oxygen, and thereby
rendered unsusceptible of solution in muriatic acid. In this
case I found the dry way more conyenient, and effected the
revivification of the metal in a well-closed charcoal crucible
over a strong fire maintained by a pair of bellows. Of the
gold supposed to be contained in the earlier antient coins,
and which must have been found as a residuum in the nitric
solution, I could discover no traces.

2d. I first examined the nitric solution which contained
no tin, to find whether it contained silver. I mixed a por-
tion of it with a saturated solution of muriate of soda; and
pat into another a plate of copper which I had weighed: 1,
1owever, found no certain traces of that metal, except in a
coin of the Mamertines.

3d. To effect a separation of the lead, I decomposed the
nitric solution with a saturated solution fof sulphate of soda,
collected the sulphate of Jead separated from the mixture,
reduced to a smal] quantity by evaporation, and either re-
duced it na crucible with charred tartar, or calculated the
quantity by counter-experiments. According to which,
100 parts of sulphate of lead might be estimated as equal
to 70 parts of metallic lead,

Vou. XVII. No. 67. R I effected

238 Contribution towards the assaying of Coins.

I effected the separation of the lead in another manner-
‘T distilled the nitric solution in a retort till it was almost
reduced to a dry mass, softened the mass again with diluted
sulphuric acid, by which means the sulphate of lead was
collected as a ponderous powder; after which I reduced it
to metallic lead.

4th. The last method afforded me at the same time the
means of detecting the small quantity of iron contained in
some of these coins, as this metal, when the thickened mass
was softened by diluted sulphuric acid, remained behind, as
.an insoluble calx of iron, along with the sulphate of lead,
which appeared coloured by the iron of a yellow ochre co-
lour. By digestion in muriatic acid, the sulphate of lead
was freed from this calx of iron, and the latter was preci-
pitated from the solution by prussiate of potash or by caustic
ammonia.

_. 5th. Nothing now remained in regard to the Greek coins
but the separation of the copper, which I effected with most
convenience by precipitating with polished plates of iron.
The difficulty which attends the process of precipitating
copper in a metallic form from a nitric solution by means
of iron or zinc, as a part of oxidated metal is thrown down
at the same time, did not occur in this case, as in the pre-
sent solution of copper the nitric acid was combined with
muriatic and sulphuric salts.

6th. The Roman coins may be divided into two kinds,
the red and the yellow. The red consists of unmixed cop-
. per, in the examination of which nothing further was to a
observed; in the yellow, however, the copper was. mixed’
with a considerable quantity of zinc.

In order to find out a complete and accurate method of
separating the zinc I prepared a nitric solution of three
parts of copper and one part of zine, divided it into four
portions, and employed it for the four following experi-
ments : ae,

Exp. 1. I decomposed one portion with sulphate of soda,
and precipitated the copper from it by iron: after the cop-
per was separated, I evaporated the solution to a dry mass
and drove off nitric acid from it several times, till the calx
of iron was perfectly insoluble. I then precipitated the tin
from the solution treed from the iron by means of potash,
and estimated the quantity by counter-experiments, accord~
ing to which 100 parts of calx of tin gave 175 parts of dried,.
or 123 parts of ignited, precipitated calx of tin.

Exp. Il. From the second portion I obtained the tin in
the following manner :—-When the copper was separated

and

Contribution towards the assaying of Coins. 959

and precipitated as before, by iron, I mixed the solution
to complete saturation with caustic ammonia, which again
dissolved the precipitated calx, and the calx of iron re-
mained behind. When the latter had been separated, I
saturated the superabundant ammonia with sulphuric acid,
and precipitated the calx of tin by mild potash. ry

Exp. II. I employed a shorter process with the third
portion of the solution containing zine. I evaporated it to
dryness, redissolved the mass in diluted sulphuric acid, pre-
cipitated the copper by arod of zinc accurately weighed, and
after its separation, precipitated the dissolved zinc by mild
potash ; and from the quantity of the calx of zinc which I
found, I deducted that portion which the rod of zinc em-
ployed for the precipitation had contributed.

Exp. IV. In regard to the fourth portion [ endeavoured
to accomplish what I had in view by the following means :
I diluted it with four parts of water and poured it into a flat
dish, the bottom of which was covered by a thin plate of
Jead. At the end of a fei days I found the solution com=
pletely decomposed, and the copper precipitated in a me-
tallic form without being rendered impure by a quantity of
precipitated metallic calx, as is commonly the case when
zinc and iron are employed for the precipitation of copper
from pure nitric acid. After the copper was separated, I
reduced the fluid, which was of a straw colour; to a small
quantity by evaporation, mixed it with a saturated solution
of sulphate of soda, separated from it the sulphate of lead
which was formed, and precipitated the pure zinc by car-
bonate of potash. Of these four ways of detecting the tin
contained in the mixture, the last appeared to me to be the
best: I therefore employed it chiefly in my examination of
coins.

That the calx of zine which I obtained was actually that
substance I assured myself by mixing it with charcoal
powder, putting small plates of copper along with it in a
covered crucible and bringing it to a proper degree of heat.
After cooling, I found that the copper was converted into
brass.

I dissolyed another part in acetous acid, and left the so-
lution to spontaneous evaporation, by which means the
acetite of zine shot into that crystalline form peculiar to it,
that is to say, tablets of six planes with equal angles.

The solutions of the Roman coins after the separation of
the zinc, when any of that metal was present, I divided into
two parts. J employed one of them to examine whether

Re they

260 Contrilution towards the assaying of Comms.

they contained silver or lead, and then to precipitate the
copper by iron: the other part I employed in order to dis-
cover the zinc. x

The following Greek coins were subjected to analysis
according to the preceding methods.

ii GREEK COINS FROM MAGNA GRECIA AND SICILY.

No. 1. A Syracusan coin of king Hiero. On the one
side the head of a young man, ornamented with a diadem :
and on the reverse a horseman with a couched lance, and
the inscription ‘Iegos. The metal had a red colour,. in-
clining to pale yellow, was exceedingly brittle, and on the
fracture fine grained and dull. The coin weighed 267 grains,
and consisted of

Copper - - - 233 ors.
Lead - - - 20
Tin - = Z 13
Tron - - - 1

267

No. 2. A Syracusan coin also. On the one side the head
of Apollo: on the reverse the Deiphic tripod, with the in-
scription, Zveaxoriwy. The metal was pale yellow, brittle,
on the fracture fine grained and dull. It weighed 74 grains,
and the component parts were :

Copper - - 614 grs.
Lead - ~ - 8
Tin - ~ - >

74

No. 3. A Neapolitan coin. On the one side a head of*
Apollo, ornamented with a laurel crown: on the reverse a
minotaur, crowned by victory, hovering over it. The sub-
scription Neawoairwy. The metal was merely pale yellow,
exceedingly brittle, fine grained, and of a steel gray colour
on the fracture. It weighed 78 grains, and contained

Copper - - - 54 grs.
Lead - - - 17
Tin - - - 7

78

No. 4. A coin of the Centuripini. On the one side a

head of Jupiter Tonans, with a bushy beard, ornamented
with

Contribution towards the assaying of Coins. 261

with a crown; on the reverse a winged thunderbolt with
the inseription Keyrogimwwy. The metal approached a golden
yellow colour, and was somewhat tougher than that of the
preceding co.ns. It weighed 167 grains, and contained

Copper - - - 142 grs.

Tin an - 14

Lead > - - il

—_

167

No. 5. A coin of the Brutii. On the one side a beau-
tiful bearded head of Mars, with a helmet: on the reverse
a soldier standing, with the inscription Bgerriwy. The*
metal was pale yellow, brittle, and fine grained on the °
fracture. The coin weighed 258 grains, and consisted of.

Copper - - - 218 grs,
Lead - - - 98
Tin - - 12

258

—_—

No. 6. A coin of the Mamertines, On the one side a
beautiful head of Apollo, with a Jaurel crown: on the re-
verse a soldier sitting, with the inscription Mapeprivey. The
mewal was pale yellow, somewhat tough, fine grained on
the fracture, dull and reddish gray. The coin weighed
195 grains, and contained

Copper - > - 165 grs.

Tm - - - 15
Lead - - - 14
Silver - - - 1

195

As I did not find any traces of silver in the rest of the
coins, the small quantity found in the above case was
present, it is probable, only aceidentally.

Il. ROMAN COINS OF THE FIRST CENTURY OF THE
EMPIBE.

1. Copper.

No. 7. On the one side the head of Augustus, with the
inscription Divus Augustus Pater ; which shows that this
coin was struck after the apotheosis of that prince: on the -
reverse a square altar, with its steps, and the subscription

i 3 Providentia.

262. Contribution towards the assaying of Coins.

Providenti@. In the field the letters usual on the earlier
Roman. copper coins, namely, S. C. (Senatiis consulto).
The coins weighed 144 grains, and consisted only of copper.

No, 8.. On the one side the head of Caligula: on. the
reverse a Vesta sitting, The coin weighed 141 grains, and
consisted also of pure copper.

No. g. On one side the head of Vespasian, with a laurel
crown: on the reverse a winged Victory, standing on the
beak of a ship and; holding out a laurel crown. The in-
scription Victoria navalis. It weighed 176 grains, and was
merely of copper.

9. Brass.

No. 10. On the one side Castor and Pollux, under the
form of two horsemen, with the inscription Cesar Au-
gustus Germanicus: on the reverse S.C, in the middle,
with an illegible inscription. The coin was of a brass yel-
low colour. It weighed_150 grains, and consisted of

Copper - - - 119 grs.
DRGs see ee
150

No. 11. A coin struck in honour of Nero and Drusus,
the sons.of Germanicus. On the one side a quadriga: on
the.reverse an indistinct figure, either a soldier standing, or
atrophy. In colour and toughness it was similar to the
preceding. It weighed 233 grains, and contained

Copper - - - 187 grs.
Zinc - = = 46
| 233

No. 12. On the one side a head of Tiberius, behind
which was an oblong impression (Tudula) |TIA/{. On
the reverse a civic crown, with the inscription Ex S. C. ob

cives servatos. This coin weighed 380 grains, and con-
sisted of

Copper - - - 3096 grs.
Zinc - - - 84
380

——

No,

Contribution towards the assaying of Coins. . 263

"No. 13. On the one side a head of Vespasian: on the
reverse a soldier sitting. It weighed 360 grains, and con-
sained

Copper - - - 293° gts,
Zinc - - + 59
Lead - - - 4
Tin - - - 3
Tron - - - i

360

No. 14. On one side the head of Trajan: on the reverse
a sitting figure, which seemed to be a Vesta. It weighed
382 grains, and was composed of

Copper - - - 396 grs.
Zinc - - - 53
Tin o - © 3

382

No. 15. Another coin with the head of Trajan: and a
similar figure on the reverse, It weighed 365 grains, and
gave

Copper - - - 294 grs.
Zinc - - - 60
Tin - ~ sie tien eri, 1

365

—

It appears from these results that the Greeks, for their
early coins, employed in general a mixture of copper, zinc,
and lead. On the other hand, that the Roman coins are
of two kinds, one of which consists only of copper, and
the other of a mixture of copper and zinc.

The custom of mixing copper with zine may be traced
back to the remotest periods. It is well known that the
oldest nations employed copper in general for their utensils,
and even for their sharp cutting instruments. But as cop-
per, and especially when cast, 1s not of itself sufficiently
hard for that purpose, it may be readily conjectured that
experiments were made at a very early period to, commu-
nicate to it a greater degree of denseness and hardness by a
mixture with other metals, none of which, except Un
alone, were likely to answer the proposed end. Such mix-
tures of copper and tin were called by the Greeks 27%
and by the Romans @s caldarium, as at present, accord~

R4 ing

264 Contribution towards the assaying of Coins.

ing to the different uses to which it is applied: for statues,
bells, and cannon, it is called bronze, bell metal, and gun
metal. it.

But as copper by its mixture with tin becomes denser
and harder, acquires a greater sj ecific gravity, and becomes
more sonorous, it is in the sane proportion rendered more
tender and brittle. It consequently ceases to be malleable.
Pliny says* Caldarium funditur tantum, malleis fragile.
The Greek coins, therefore, consisting of such mixed
metals, do not scem to have been struck, but to have been
cast, and the circumstance of their being generally concave
on one side must be considered as a-consequence of the
contraction or warping occasioned by their cooling. _

Among the mixtures (temperatura) of copper mentioned
by Pliny, there is one in particular, which he calls @s te-
nerrimum, which is found in the Syracusan coins: it con-
sists of 100 parts of copper, 10 parts of lead (plumbum
nigrum), and 5 parts of tin (plumlum argentarium) ; of
which mixture 7 says that it appears with that colour
which he calls the Grecian (color Grecanicus). Under the
term plumbum nigrum of the Roman writers we must
understand our lead. Their plumbum argentarium, album
candidum, however, is not lead, but the Kaccirezos of the
Greeks, or our tin; and Pliny clearly means by it tin fused
from washed ore. The ate stannum however occurs in
Pliny, but this word was not used by the Ronians to denote
our tin but a mixture of silver and lead, or that substance
which, in the Janguage of the German miners, is called
werkbley+, or merely the werk. In regard to the Roman
copper coins, they consisted, as already seen, either of pure
copper or of amixture of copper and zinc, which was called
by the Romans aurichalcum, or orichalcum, and also es
Corinthiacum, and seems to belong to the same class as our
brass, pinchbeck, similor, &c. Metallic zinc however was
at that time entirely unknown, and no traces of it are to be
found before the 13th century, at which time it was men-
tioned hy Albertus Magnus.

It clearly appears, from several passages in antient au-
thors, that the antients employed a method for preparing
this mixture of calamine (cadmmia fossilis) similar to that
which we employ for the preparation of brass. Festus says
expressly, cadmia terra aces conjicitur, ut fiat orichalcum.

But it is proved, by a passage in Aristotle, that another

* T.ibs xxxiv. cap..20.

+ Lead from which the silver coatained with it in the ore has not
been separated, Epir,

people,

Contribution towards the assaying of Coins. 268

people, the Mossinzci, who resided near the Euxine sea,

understood and practised this art before the Greeks or the
Romans. That author, in his work De Mirabilibus Aus-
cultationibus, Paris 1619, says, des Mossinecum (Mac-
civoixsy yaanxov) splendidiore candore eminere ferunt, non
adjecto stanno sed terra quadam istic nascente simul in coc-
tum. Aique ejus adtemperature primum inventorem celata
arte, neminem docuisse, et proinde priorum temporum era-~
menta iis in locis postertoribus longe preestantiora depre-
hensa.

Philologists seem entirely to have overlooked this passage,
from which the etymology of the German word messing, or
more properly, as it was formerly written, moessing, which
signifies brass, may be clearly and simply deduced. It is
improper to derive it from mschen or maischen, to mix, for
the antients had no idea of mixture in the preparation of
this metal. They did not know that a metailic substance
is actually mixed with the copper, for they supposed that
the calamine only possessed a secret property, by which it
communicated to coppera golden yellow colour*. The
terms latun (luton, laiton), deduced from the Arabs, and
introduced into some of the languages of the western part
of Europe, are of later orjgin.

It appears from the above passage of Aristotle, that the
art of converting copper into aurichalcum, by means of
calamine, was at first kept a secret; but it seems to have
become more common about the time of the Roman em-
pire. But the cause of this new alloy of copper, after it
was made generally known, being mixed with tin and lead,
and used in preference for coins, no doubt was its gold
colour, which excelled that of the pale yellow awrichaleum,
aud its tonghness and malleability, arising from the mix-
ture of calamine, which rendered it fit to be struck into
coins, whereas the old mixtures with tin could only be
cast.

When I placed Corinthian brass in the same class as
ayrichalcum, this arrangement is in contradiction to the
opinion that this metal was produced from the fused metal
of the gold, silver, and copper statues, and other articles
formed into one mass when the city of Corinth was taken

* J have since found that I am not the first person who has given
this etymology of the word mess'ag; for Mathesius says: The Latin
Bible retains Anichal um, that is, messing (brass), which word is cer-
taiply cerived from the name of the people called Messoxocc/, mentioned
by Aristotle.

1 and

266° —- Contribution towards the assaying of Coins.

and destroyed by Lucius Mumminus. It is however possible:
a similar metallic mixture may have been accidentally pro-

duced during the conflagration of that rich city, but no

proof of this has ever been found by actual examination.

It appears rather from Pliny, that the expression ces Co-

rinthium was aterm of art applied to a metallic mixture in

high estimation among the Romans, and which, in conse-

quence of a more careful choice in the ingredients, and

more exactness in the proportions, may have been different

from aurichalcum. But if the opinion of antiquaries, that
the coins struck in the time of Tiberius of a gold colour
were of real Corinthian brass be well founded, the mixture
has now been determined by assaying *.

In regard to the small quantity of tin and lead contained
in the coins of Vespasian and Trajan in mixture with the
zinc, the addition of these does not appear te have been a
role. What Pliny says of the metal destined for statues °
and tablets, that a third part of old copper was added to it,
was In all probability the case also in coins, and the mass
must therefore have been different according to the different
nature of the fragments of copper employed for the mix-
ture.

My researches in regard to the metallic mixture of the
antient coins was confined to a small number, and there-
fore are not sufficient to admit of general conclusions to be
drawn from them respecting the coins of eyery nation at
different periods, and according to the different changes in
the mixtures. For this purpose a much greater number of
docimastic experiments would be necessary.

They are, however, sufficient to excite douhts in regard to
the abundance of gold and silver which are supposed by
some to be contained in the antient coins, and to show that
the hardness of the Greek coins, and of various edged
and sharp-pointed instruments of the antients, cannot be
ascribed either to any art now lost, nor to a supposed addi-
tion of arsenic or iron, but merely to a mixture of tin f.

XLV. On

* In order that I might observe the real colour and appearance which
these coins had when first struck, I caused two of them to be struck
anew. The first, which was a coin of Tiberius, with a Ceres in a sit-
ting posture on the reverse, was fused, and then rolled flat, and struck
into a coin. The other with the head of Vespasian, and on the reverse
a sitting figure, with the inscription Roma, was only smoothed, and
then struck anew. I then caused some artificial imitations of Corinthian
brass to be struck also, that I might compare them with these antient
coins.

t The latest chemical analysis of current coins with which I am ac-

quainted

[ 267) ]

ALY. On Cinis; a Kind of Alkaline Earth formed during
the Incineration of Wood, not yet noticed hy Chemists in
their Nomenclature. Addressed to GrorGk Prarson,
M.D. F.R.S. &e. by Samurt L. Mircum., M. D.
Member of Congress, Sc. ina Letter, dited New York,
September 20, 1803, and communicaied to Mr. Tituocu
at the particular request of the Author.

eraheremcsa of combustion have by no means been
examined to their full extent. The decomposition of wood
by fire is a yery complicated process. There is much more
to be remarked in it than has been noticed in books. In
particular the formation of a new kind of alkaline earth ren-
ders it remarkably interesting. In New York, where wood
is the principal fuel of the inhabitants, and where great
quantities of potash are manufactured from the fixed mass
which remains after burning, I have availed myself of the
opportunities afforded to find out some of the details. Those
I have endeavoured to express in the following record of
facts :

When a quantity of wood (in a solid, not a rotten state},
oak or hickory for example, has received anticrouon (the
repelling principle or caloric) enough to render it capable
of decompounding the gaseous oxide of light (oxygenous
air), it begins itself to lose its vegetable structure and to
assume new forms. The anticrouon first dilates the wood
by increasing the repulsion among its particles ;. then it re-
pels the water which it contained to such a degree as to
convert it into steam or aqueous gas. The moisture being
thus exhaled, and the wood left shrunk, perfectly dry, and
highly heated, its carbon attracts a portion of oxygen from
the gaseous oxide of light with which it is closely invested.
The immediate consequence of this is, that a portion of
detached light becomes visible, and a quantity of extricated
anticrouon spreads through and over the wood, and extends
about the surrounding spaces. In proportion to the amount
and rapidity of the oxygen, abstracted from the gaseous
oxide of light, will the extricated light be yivid, and the
separated heat be intense. While the liberated anticrouon:
and light, just nascent from their latent condition, are

quainted is that by Dize, in Rozver’s Olservat. sur la Physique, for the
year 1790. But there seems to be great reason to doubt their being cor-
rect, because the author makes all the coins to consist of copper and tin,
without saying a word of the /ead found jp the Greek coins, or the zinc
found in the Roman,

thus

£68 On Cinis.

a

thus expending themselves upon the surrounding objects, @
portion of carbon, repelled from its connections in the wood,
dies off m connection with a portion of atmospheric oxy-

en in the form of carbonic acid air. No sooner has this

appened than the phlogiston (hydrogen) of the fuel is re-
pelled from its association in the timber, and forming 2
new association with the oxygen of the gaseous oxide of
hght, constitutes blaze; a meteor burning in an aérial form.
This phlogiston and oxygen, after chemical union, turn to
steam, and finally condense to oxide of phlogiston or water;
while an additional quantity of anticrouon and light are
shed around after detachment from the oxygen, which has
just left them to combine with the pblogiston to form water.
While these changes are going on, a portion of septon
(azote) sometimes from the vegetable body, but more
commonly from the septous (azotic) part of the atmosphere,
comnects itself with a part of the separated phlogiston and
turns it to volatile alkali (ammoniac). A part of the oxygen
also combines with the basis, whatever it is, of the pyro-=
ignic acid, and this, by force of anticrouon, is repelled
into gas.

Thus, during the time that wood, oxygenous air and
azotic air undergo their trip/e decomposition, liberated light,
Jiberated anticrouon, carbonie acidsgas, flame, oxide of
phlogiston or water, ammoniacal gas and pyrolignic acid
gas are quickly produced.

But these are only a part of the curious products of com-
bustion. There are several freed substances formed whose
history is no less worthy of notice than that of the volatile
ones already enumerated. These are contained in the caput
mortuum, or residuary mass left on the hearth or in the
fireplace after incineration, and called “* ashes.”

‘Phese ashes are a very heterogeneous collection of materials.
They may be properly divided into two classes, to wit,
those which readily dissolve in water, and such as with dif-
ficulty incorporate with that fluid. The former is the saline
and the Jatter the earthy part of the ashes, And both of
them, .as they most clearly do not preexist in the wood, are
produced by new combinations of particles during the act
of burning.

Of the saline portion of wood-ashes, the predominating
mgredient is the vegetable fixed alkalt or potash. When
recently formed, and fresh from the fire, this fixed salt is
in a caustic state. By exposure to the air in a cool place
for some time it attracts fixed air and becomes a carlonate
of potash. Very commonly too this alkali, when exposed

in

On Cinis. calaiey

in foul and nasty places; turns to a septite of potash, by
attracting and neutralizing the septic acid recently engen-
dered in such situations. Very commonly too this alkali is
found to be combined with sulphuric acid into a sulphate of
potash; and lately on examining some curious samples of
this salt from the manufactores, | found them to contaia
phosphoric acid.

In these two Jatter cases, sometimes external causes, and
at other times the woods burned, farnish a quantity of
sulphur and phosphorus, whiclr acidifiable bases first turn
to acids during the process of combustion, and then the
newly formed acids connect themselves with the potash to
constitute compound salts. Frequently likewise muriate of
soda is discovered in wood ashes; but this seems to be de-
rived from tke culinary salt employed in cooking.

After these saline substances are extracted by water in the
course of lixiviation or letching, a large quantity of earthy
matter remains behind. The proportion of this varies im
the ashes of different vegetables, but in that of sound oak
and hickory perhaps amounts to eight-tenths of the whole.
In this state it is called letched, dead, or soap-boilers’ ashes,
and is bought at a high price by farmers m the netgh~
bourhood of New York for manure. {n its crude condr-
tion, as taken from the vats er Ietch-tubs, if abounds with
charcoal, soot, and other half consumed vegetable sub-
stances which had escaped the destructive force of the fire.
Particles of silicious and argillaceous: earths are generally
present, derived in all probability from the sweepings of
floors, the crumbling of chimneys, and other external
sources. Besides these there is found a quastity of iron;
though I have not found any of the manganese which some
experimenters talk of. But above all,. this residuary mass
abounds in lime, which is intentionally added, in its caustic
state, to attract carbonic and phosphoric acids from the
potash, and thereby to render that alkali quick and active ;
or, in maritime situations in America, a large admixture of
calcareous earth is derived from the roasting of clams,
oysters, and other testaccous animals, and the addition of
their shells to the ashes. But by far the greatest proportion
of letched ashes consists of a peculiar kind of earth, whick
remains after all the before-mentioned materials are sepa-
rated. This earth is of a whitish colour and alkaline qua~
Jity, as you will see by the sample I herewith send you for
experiments. I think it differs materially from lime, ba-~
ryles, magnesia, strontian, or any other known species “4

earih,

80 On Cinis.

earth. And yet plentiful, common, ‘and important as it
is, science has not dignified it with a name. ;
To judge of the excellence of soap-boilers’ ashes for ma=

nure, the following facts may give you the requisite in-
formation :—After all the salts are extracted it sells for ten
cerits the bushel *, or for one dollar and thirty-seven cents
the cart load of fourteen bushels, deliverable at the city
wharf. When this is delivered to the farmer at his own
landing, the additional ccst of freight to the country (as
from the city of New York to Plandome, 25 miles) amounts
to twenty-five cents a load ; making in the whole one hun-
dred andsixty-two cents: To this must be added the expense
of drawing and spreading it ori the land. “All this the farmers
pay; and yet such is the competition for these refuse ashes,
that it is not uncommon for the farmer who buys to ad-
vance the cash to the soap-boilcr six or twelve months. be-
foreland. When scattered over sterile ground and ploughed
in at the rate of twelve loads the acre, it produces great crops
of wheat, clover, and other sorts of grass and grain; and
its effects are so durable, that the fertilizing operation of it
may be often discerned for seven, ten, or sometimes even
twenty years. It is this disposition of dead ashes to endure
which makes it cost so much more dear than street dirt ;-
a material which, though very valuable, is by far more
transient.

Now, on considering the value and efficacy of letched
ashes it would appear, that though some of its virtue was
derived from the charcoal, sooty and other undecomposed
vegetable matter, lime, and the remnant of carbonate of pot-
ash which has escaped the lixiviating process, yet that its
principal worth was derived from the peculiar earth which
constitutes the chief part of its bulk. It is tiie to give it
a name, and to introduce it into the nomenclature. And
in case you should agree with me in opinion as to the facts,

I flatter myself you will agree with me also in distinguish
ing it by the word Cinis, or the earth of wood-ashes. And
I must own such a coincidence would bevery flattering to
me with one who has distinguished himself so much in 1m-
proving the logical as well as the physical department of
science as Dr. Pearson. Under that title it has as good a
right to stand conspicuous, and be known and talked of, as
either magnesia or lime, potash or soda; all of which are
to be, like cinis, considered as compounds, but retained

* Our bushel is the sane with your Winchester measure.

a ‘ nevertheless

Account of a Shower of Stones. a7 1

nevertheless in the list of simples until their constituent
facts can be ascertained by analyses.

It is worthy of remark, that this earth which is so prized
in America for a manure, was esteemed of old in Asia as
an ingredient in a cement: among the antient Syrians it
was one of the materials forming the plaster of their walls ;
and as it holds an intermediate place between lime and pot~
ash, it can easily be conccived how it may act both as a ce-
ment andamanure. It is to be hoped chemists will turn
their attention more particularly than has been heretofore
done to this important but neglected subject.

XLVI. Account of a Shower of Stones; in a Letter from
the Prefect of the Department of Vaucleure to the French
Minister of the Interior, dated November 10, 1803.

«ec

Ox the sth of September, between ten and eleven in
the morning, being at Bastidonne, a village situated be-
tween Perthuis and Mirabeau, I heard a very extraordinary
noise, which appeared to proceed from the mountains of
Luberon. My mind being preoccupied, and following, at no
great distance, the drums of the national guard of the com-
mune which I was going to visit, I paid very little attention
to the foregoing circumstance, and therefore | can say no-
thing of the effect of this noise from my own particular ob-
seryation; but [ have since found that it was heard at the
‘same*moment by the inhabitants of the several communes
which I have since visited, as far as Gordes. The municipal
officers, and various other persons with whom I have con-
versed in these communes, agree in declaring that the noise
appeared to them severally to be at the distance of a quarter
of a league from the place in which they then were; all
adding, that after a sound that appeared to be thunder,
which might Jast above five or six minutes, they distinctly
heard a whistling in the air, which some compared to a
swarm of flies passing near them, and-others to the whis-
tling of bullets.

“ In the commune of Gordes some persons imagined
they perceived a trembling of the earth between six and
seven in the evening of the same day. j

« I requested the municipal officers, who mentioned this
phznomenion to me, to endeavour to discover the cause, and
to send me whatever information they could procure ; but
have hitherto received only the single proces verbal, a copy

o

272. Account of a Shou er of Stones.

ef which I send you. It was accompanied with a’ stonty
which I cannot yet transmit to you, because the owner 3s
unwilling to give it up. I shall write to him, and T do not
doubt that his answer will authorize me to send it*. This
stone, which nearly resembles those used in paving, is
about a foot in circumference. It is heavier than flint, is
covered with a black crust, its interior colour being ght
gray, mingled with iron colour. It appears to contain par-
ticles of iron, and some brilliant grains like silver.

* The proces verbal ascribes the noise, heard in the
morning of Saturday the 8th of September, to a volcanic
explosion ; and this was the first idea which I entertained of
the matter. But this idea was not confirmed by the ex-
istence of any crater; beside, is it to be presumed that the
noise of an explosion could be heard at different places with-
im. twelve leagues distance from the spot, at the same mo-
ment, and attended with the same circumstances? Is it
to be supposed that an explosion could cast a shower of
stones over twelve leagues of cireumference ? Now the stone
which fell near Apt explains the whistling that followed the
first noise, which, it is very certain, could be only the ef-
fect of the fall of like stones, which, by the rapid motion
produced by their weight, were invisible to the eye. I leave
it to the learned to explain this phenomenon; and in the
mean time I shall write to all the communes in the neigh-
bourhood of Luberon, requesting that more particular re-
searches into this matter may be made.

<¢ Letters from Aix state that the noise of the 8th of
September was heard at that place, wheré it was supposed
that the powder magazine of Avignon was blown up.

«© (Sioned) M. A. Bourbon.

« P.S. IT forgot to say, that the’stone mentioned in this
Jetter has a foetid smell which resembles that of sour milk.
Struck with steel it yields very few sparks.”

A.true copy. The Minister of the Interior, CHAprTaAt.

Proces Verbal.

© On the sth of September,: 12th year of the republic,
about half past ten in the morning, there appearing only a
few light clouds in the heavens, and the weather being re-
markably calm, a noise resembling that of acannon fired at

* This stone has been since transmitted to the Minister of the Inte-
rior, and was presented to the National Institute on the 24th of Bru-
maire, and is now deposited in the Museum of Natural History, It is
exactly of the same kind as those Which have been gathered after similar
phznomena :

the

Account of a Shower of Stonés. 273

the distance of a quarter of a league, was heard with the
same force, and’ attended with the same circumstances, by
a number of-individeals in variows places; but more parti-
‘ularly in the country, at the distance, at least, of seven or
eight leagues from Apt, the principal town of the fourth
district of the department of Vaucluse. This noise, how=
ever, could be the effect only of an unusual explosion; be-
cause it is certain that throughout the whole extent above
mentioned, and at that hour, no cannon was fired, nor was
there any explosion of gunpowder. It produced; by the
yepetition of the sound in some of the mountains, the same
‘effect as the explosion of a cannon which differs in this
respect from claps of thunder. This circumistance, which
at first surprised all who were witnesses of 1t, was accom+
panied with a phenomenon still more extraordinary. On
the same day, and at the same hour,.citizen Joseph Jully, a
farmer in the district of Apt, and his wife, being about five
hundred paces from the country-house of citizen Bartholo-
mew de Vaux; situated north of the town of Apt, at the di-
stance of about a quarter of a league, in the limits of San-
rette, having heard the noise above mentioned, immediately
afterwards heard, for the space of six or seven minutes, a
whistling which increased in sourid as it approached, and
announced the fall of some solid body. Being terrified,
and casting their eyes upward, the wife of Jully perceived
a black substarice, whose fall on the ground both she and
her husband heard distinctly; after which the whistling
ceased. The wife of Jully states that this black substance
must have fallen in the vineyard of citizen de Vaux. The
wife of the latter, being then in the fields, at the same mo-
. ment heard the same noise and subsequent whistling, but
being alarmed she ran into the house, and neither saw nor
heard the fall of the above substance. Her son, being then
at work three or four hundred pace’ from the house, also
heard the noise; the whistling, andthe sound of the fall
of a body, which, however; he did not see. At the sante
instant, Marguerite Hugues, widow; and Marie Jean, wife
of Jacques, Julien, being on the road frora Villars to Apt,
heard the same noise, the whistling and the fall of some
substance in De Vaux’s vineyard, which adjoins the said
road. After the sound of the fall; the whistling ceased. It
appeared to them that the above substance did not fall at
more than thirty paces’ distance from them.

** As soon as the report was spread that sortie considera-
ble large substance had fallen in the above vineyard, a great
wagerness was manifested to search for it, The attempt was

Vou. XVII. No. 67. S at

o74 Account of a Shower of Stones.

at first fruitless; but on the 10th, De Vaux’s son, in cross*
ing the: vineyard, perceived, at the distance of about thirty
paces from the house,.a large hole newly made between two
rows of vines, whish.denoted the place where the substance
must have fallen. He was confirmed in this opmion when
he perceived that some small: pebbles at the mouth of the
hole were ground to:powder.. He then dug, and found an
extremely hard stone weighing seven’ pounds’ six ounces,
and could no» longer doubt that this was the substance the
fall of which had so alarmed the neighbourhood.

** On the rumour of these facts, I, the sub-prefect of
Apt, having sent for the stone, which had: been: given to
citizen Joseph Brun, merchant of the town of Apt, by De
Vaux’s son, proceeded, in company with several of the
public functionaries, on the 18th of September, to De Vaux’s
country-house, and having examined the place from which
the stone was dug up, we showed the stone to De Vaux’s
son, who instantly knew it to be that which he had disco-
vered and dug up as above mentioned, it being buried in the
earth to the depth of ten inches; which stone he had stated
to us he had given to-citizen Joseph Brun. We also-took
down the statements of the persons before mentioned, as al-
ready given:: im consequence whereof we have dyawn up this
present proces verbal, which we send to the prefect of the
department of Vaucluse, together with the said stone, upon
which we have placed our seal, to the end that he may make
the above circumstances public, if he shall think proper to
do so, that an explanation may, if possible, be obtained cf
this phenomenon.

* Done at Apt, on the 19th of September 1803:
*“ The Sub-prefect of Apt,. (Signed) ‘TrRRas,
s¢ P.S. It is to be observed, that in citizen De, Vaux’s
vineyard there is no stone of this species, nor any stone of
equal size. The persons accustomed to traverse both: the
mountains and the vallies of the district of Apt, do not re+
nore ever to have seen, in any part of it, a stone of this

ind.
“True copy. (Signed) The Prefect of Vaucluse,
“¢ C, A. Bourpon.

“True copy. (Signed) The Minister of the Interioz,

6° CHAPTAL. .

XLVII. An

+ meithfh. B752 9: TRI
XLVI. An improved Method of heating Boilers ; leing. an
Account of the Way in which the Fire is applied to one of
the large Boilers in Messrs. Meux’s Brewery.

‘dae best method of applying fire to boilers has only very
lately been made-a subject of inquiry ; and it may with great
truth be asserted, that till within these few years by tar the
ereater part, of the fuel was entirely wasted. It was cus-
tomary to have a fire under the whole bottom of every boiler,
and the grating which carried the fire was generally nade of
nearly the same size as the bottom of the boiler ; sometimes
even considerably larger. The consequence was, that the
principal part of the heat was. discharged’ by the chimney
instead of being communicated to the contents of the boiler,
_and even a great quantity of the fuel was sent away, uncon
sumed, in the form of dense smoke.

_. Count Rumford’s writings have tended very much to turn
the attention of individuals to this subject, and to econo=
mize the consumption of fuel. The winding flues he has
so strongly recommended to be put under large boilers may
be considered as highly preferable to the method that pre-
vailed so generally before ; nor in bringing forward the pre=
sent article have we any intention to depreciate an improve-
ament highly valuable in itself; but having been permitted
.to inspect the large boilers at Messrs. Meux’s, and having
witnessed their effects, we think we shall render an essen-
tial service to people engaged in different manufacitires, in
which boilers on a large scale are employed, by laying be-
fore them the arrangements that have been adopted in get-
ting (as workmen term it) the boilers at their brewery,
where proper comparative experiments are made in every
thing that regards the economy of so important a concern
under the direction of an able and experienced engineer,
and at an expense which would be ruinous to any under-
taking of less magnitude.

In constructing a boiler two objects ought to be kept in
view t first, that a large portion of the heat produced by the
combustion of the fuel may be communicated to the boiler
instead of being uselessly expended by the chimney; this
is what is aimed at, and in some measure attained, by the
winding flues recommended by count Rumford: secondly,
that the heat may be communicated to the boiler as rapidly
as the nature of the business may require; this is what has
been attained at Messrs. Meux’s, and with a less consump-
tion of fuel than by any former arrangement, count Rum-
ford’s not excepted, }

$2 ° The

$76 An improved Method of heating Boilers.

The merit and success of the construction seems to dew
pend on making the flame and heated air impinge, and as
ft were press eat the boiler, instead of merely passing
along easily to the fluc. For this purpose Mr. Woolf, the
engineer at the brewery, keeps his fire forward and forces
the flame, by interposing a wall or breast-work A (fig. 1.
Plate VII.) betweenit and the flue, to play against the bot-
tom of the boiler, to which a large portion: of heat is given
off before the current of flame and heated air, which is next
-earried round the boiler, ean find its way to the chimney.

In fact, there are two fire-places under each of Messrs.
Meux’s large boilers, separated from each other by a party~
wall B, fig. 2. In this figure one of the fire-places only is
shown, and the party-wall ; that is, a little more than one~
half of a horizontal scetion of the furnace. The wall AB,
besides answering the purpose of separating the furnaces,
as already mentioned, serves to support the bottom of the
boiler C, which carries an immense weight when filled with
liquor. ‘Fhe upper part of the boiler is not shown im the.
engraving. Ft is not am open boiler but finished m the form.
of a dome, the summit of which rises from the centre of
the bottom. to a little more than twice the height of the part
shown in the figure. At a convenient part it is furnished
with a man-hole, to which a steam-tight cover is fitted, for
the convenience of admitting the workmen to clean it out
when necessary, and another hole, also fitted with a cover,
‘for admitting the hops.

‘The extremity of the bottom, or the lag, as it is called,
of the boiler, rests on brick-work a (fig. 2.) and that part.
of it which comes immediately over the fire is defended by
brick-work @ (fig. 1.), as experience showed that this pre~
caution was necessary.

After the flame has passed from the bars of the furnace
over the breast-work A, striking with force against the bot-
‘tom of the bower, it finds its way into the circular flue D,
which goes round the boilet to the place where it is jomed:
to the chimney E, by the opening or door F, which 1s fur-
nished with a vent and register m the usual method, and
which is shown in the figure. The flame aud heated air is
not allowed, however, in passing into the circular flue D,.
to keep in contact with the copper, but is forced ‘first to
descend and pass under a little arch m, by which contri-
vance that part of the boiler, which otherwise would soon be
cut away, as it were, by the intense point of the flame, is
defended from injury.

In these furnaces Mr. Roberton’s contrivance for burning
the smoke is made use of, which is found completely to:

& answer

An improved Method of heating Boilers. 277

answer the purpose intended. Having in a former number
of our work given an account of this invention, we need
not here repeat it. We think, however, that there will be
no impropriety in pointing out an addition which has beer
made to it since its first adoption, and which is a consider
able improvement, namely, a method of getting rid of the
clinkers or vitrified scorie, invented by Mr. Woolf. This
contrivance, which is very effectual, has at the same time
the merit of being extremely simple. The cembustion of
the fuel commences, and is chiefly carried on, on the hori-
zontal part of the bars: from this the fuel is pushed back
from time to time to the inclined part, and at last the vi-
trified portions fall from the lower end into a cavity 0, the
bottom of which is furnished with sliding horizontal irom
doors. These from time to time are drawn out a certain
length by putting an iron hook into a hole x, in the handle
of the sliding door and drawing it outward, which dis-
charges the clinkers into the ash-pit.

The contrivance we have just deseribed is found also to
answer another very good purpose. These boilers are filled
and emptied several times a-day, and between each time it
is necessary for people to go in and clean them out. To
enable them to do so the whole of this large apparatus must
be reduced to a moderate temperature; a circumstance that
used formerly to take a considerable portion of time, with
every possible care at the same time to damp the fire. The
introduction of these sliding doors behind the bars has been
found to present a mean for cooling the boiler very rapidly.
When they are all drawn out at once, while the contents
of the boiler are discharging, such a draft of cold air takes
place through that opening as absolutely to drive down the
flame through the bars, and to cool the boilers so effectu-
ally, that by the time it is empty, which takes about twenty
minutes, the people are able to go instantly into it.

To give as much room as possible about the front of the
fire-place, and at the same time to msure sufficient strength
to the structure of brick-work inclosing the furnace and
boiler, which from the bottom of the ash-pit to the top of
the dome of the boiler is about twenty-one feet; the front
stands on pillars made of cast iron.

Fig. 3. is a front view of one-half of the erection; (that
is, enough of it to show the front of one of the two fur
naces.) Thq air which is admitted above the fuel, to im-
flame the smoke, as described in our account of Mr. Roe
berton’s invention (vol. xi.), enters by the two smail quae
drangular apertures on a line with the lower ornament of

53 the

278 An improved Method of heating Boilers.

the capital of the iron column. These apertures°grow
wider in two of their sides, and closer in the other two, as
they approach the furnace, till at last they throw in a thin
plate of air of the whole width of the fire. The mouths of
these apertures are made .of this form for the convenience
of more easily shutting them when the fire is to be at any
time damped... The coals are introduced immediately below
these apertures over the inclined iron plate, which may be
better seen in the vertical section, fig. 1:

The plate, illustrating the present article, which is en
graved by Mr. Lowry, is executed in‘such a masterly man
ner as to render any further description of the parts umne~
cessary. <A bare inspection of the plate will show them
sufficiently, without the necessity of our blotting it over
with more Ictiers of reference?. The letters-A, B, m, and
0, in fig. land 2, refer to the same things in both.

These furnaces answer the purpose so well, that though
the two are both lighted to bring the worts to boil, one of"
them is soon after damped out, and the remaining one only
kept burning till the process is ended. And itis no uncoms
mon thing for the. workmen to be under the one-half of
the boiler, making necessary repairs in the furnace, while
there is a fire under the other half, from which they ar
only parted by the wall B before described. °

We mentioned in a former number, that the new boiler
on Mr. Woolf’s principles now constructing is intended to
be employed in generating steam, to be thrown ito the
Jarge boilers in this brewery, instead of heating them by
fire applied directly to the boilers themselves. The very
boiler we have been describing is one of these. But the
present arrangement is still to remain, that fires may be
employed as heretofore at any time that the new boiler or
furnace may need repairs. Besides, there are many busi-
nesses which do not admit of the boilers being heated by
steam ; and to the proprietors of such, the present article
cannot fail to prove highly acceptable. *

The liberality of the proprietors of the extensive brewery
where this boiler is erected, in admitting the public to par-
ticipate in the beneficial result of economical experiments,
ascertained at a yery great expense, cannot be sufficiently
praised. No person to whom a view of their improvements
can be any way serviceable is refused admission into their

remises ; and we are confident. that the public, those at
east to whom the economical and beneficial expenditure of
fuel is an object, will feel, as we do, the weight of the ob-
ligation, 0°... ‘8 be ro -
dels XLVIUI. de-

KLVIIL. Account of the Meteor seen on the Evening -of
- Sunday, November 13th. 1803; with some Observations
on the best Means of ascertaining the Altitude, Bearing,
Magnitude, Distance, and Velocity of such Phenomena.
By Mr. T. FirMINGER. . *;

T was at first advertised of the appearance of this meteor
‘by a very strong hight » hich. rendered all the surrounding
objects visible: it was, indeed, so very bright that I could
have read a newspaper by it without the least difficulty. 1
no_ sooner saw this light than 1 was apprehensive of the
cause which produced it, and upon looking up saw the
meteor to the south of the zenith, and about twenty-five
degrees in azimuth to the east of the meridian ; it was then
moving with a great velocity towards the west in a rather
north-westerly direction; its course, however, was very

nearly in a line perpendicular to the meridian. nS
‘At its first appearance it seemed quite round, and well
defined, except the part apposite to the direction in which
it was moving, which secined to project a little, and to ter=
minate in a tail that extended to a small distance from it (sce
uppermost figure, Plate VI.) On each side of this tail
there were two or three smaller balls, tinged at their ex-
tremitics with yellow.and orange colours, and one or two
with purple. The whole body continued to move together
avithout any sensible difference in either its colour or shape
til] within about a second or a second and a half before its
‘disappearance, when it suddenly altered its figure to some
thing like the shape of an egg, (see the lower figure, im
which AB represents the direction of its motion.) Atthie
moment its light became so strong that it was not with-
‘out much dificulty [ was able to keep looking at it. I
should think its light was full two-thirds as intense .as that
of the sun when upon the meridian, It seemed at this time
as if the meteor had before been covered with one external
‘coat, which now burst or separated in the middle the whole
length of its longest diameter, and exposed a surface with
a brightness far surpassing its former lustre. I may, how-
ever, have overrated its light, by supposing 1t equal to two-
thirds of that ef the sun when upon the meridian, for it is
to be observed that the pupil of my eye must have been
before much_ dilated from the darkness of the night, to
svhich it bad been exposed at least a quarter of an hour;
‘ut the comparison relates to the effect it produced upon my
nav ; eyes

230 Account of the Metcor

eyes at that moment, when compared to what the direct
rays of the sun would produce in the middle of the day.

The diameter of the large ball at its first appearance, by
comparing it with the moon, (which is the best object E
know of for that purpose) I should think subtended an
angle of at least twenty minutes of a degree; the smaller
balls, which appeared all nearly of the same size, were about
a fifth part of the diameter of the large one, and I should
suppose subtended angles of about four or five minutes of
a degree. The altitude of the meteor was about 50 or 55,
degrees, and continued nearly the same during the whole
time of its appearance, which was about four seconds and a
half or four and three quarters ; it vanished instantaneously
with an azimuth of about 75 degrees to the west of the
meridian. :

The azimuth and altitude were afterwards estimated by
means of a needle and compass and a small Gunter’s qua-
drant, which I took to the place where I stood when I saw
the meteor, and they are I believe pretty correct, as the
surrounding objects. assisted me very much in making these
estimates. “I also measured with a sextant the apparent path
which it described, and found it about 85 degrees. Its —
disappearance was at 8" 30™ 39° mean time, which I had an
Spporuaiyy of ascertaining by an excellent chronometer of
Mr. Earnshaw’s construction which I happened to’ have
with me, ‘pe
~ In two minutes after the appearance of this meteor ]
heard a noise which sounded like a distant clap of thunder,
or like the rumbling of a coach heard at a quarter of a mile’s
distance going over a stone pavement; it was pretty loud at
first, but got gradually fainter until it was no longer audible,
and, what was very surprising, it seemed to follow the very
same track the meteor before had appeared to move in: it
‘Tasted a minute and forty seconds.

The appearance of the meteor as it moved along had a
very great resemblance to that of a skyrocket seen at the
distance of about a mile. I have also since met with per-
sons who have seen “meteors, and they have generally de-
scribed their appearance as very much resembling that of
a skyrocket, which may have induced some observers of
these phenomena to think they heard a hissing noise some-
‘thing like what these rockets occasion ; for the imagination
is so forcibly impressed by such comparisons, and the du-
ration of the appearance of meteors so very short, that it
js not at all surprising we should be misled in our ideas, and

: combine

seen November 13, 1803. $31

combine appearances with sensations which have no other
existence than in the imagination.

The noise that followed after this meteor was particularly
noticed by several people, who, although they saw nothing
of the appearance, yet were alarmed by the singularity of
the noise : some conjectured it to be occasioned by the over-
setting of a coach, others by the rattling of a fre-enginey
and others by a distant clap of thunder.

With respect to the height of this meteor, or its dimen-~,
sions, nothing more can at present be inferred than what is
derived by comparing the interval of time elapsed between
seeing the meteor and hearing the noise which it occasioned
in its passage through the upper regions of the atmosphere.
By that interval of time, its distance from me when first
observed would appear to have been about six and twenty
miles; and its perpendicular height about three and twenty
miles above the earth’s surface.

This method of obtaining its distance, however, must
be liable to great uncertainty, and can only be adopted as
an approximation, where better means are not to be ob-
tained ; for although the velocity of sound is pretty well
ascertained at distances near the earth’s surface, yet its ve-
locity at the height of twenty-three miles above the earth
may be very different from what our calculations give it. The
real distance, therefore, can only he.obtained, with any de-~
gree of accuracy, by observations made at different places
at a considerable distance from each other. Jt is much to
be wished that people, who happen to be so situated as to
have an opportunity of observing a meteor, would take all
possible pains in the first place to obtain its altitude as cor-
rectly as they can, which may oftentimes be done with
ese accuracy ; for although the mind at the moment may

e altogether engaged in admiring the beautiful and curious
appearance of such a singular phenomenon, yet I believe
it will be generally in our power to remember the precise
place where we were when such a circumstance happened ;
for people in general stand still when any thing chances to
strike them with surprise, and before they proceed to re-
move from that place take notice of the objects that sur-
round them: and hence it very naturally follows, that when
we give an account of the appearance of any phenomenon,
we are always particular in our description of the spot from
whence we saw it. If, therefore, at a considerable tme
after, we were to go to the place where we saw a meteor, the
strong impression left on the imagination of its apparent
situation would enable us to ascertain its altitude oe

being

282 _ Account of the Meteor

deing- lable to a mistake of more than about ten degrees;
and in a close situation, as in a strect, or among houses, it
avill oftentimes happer that. some object will intercept part
-of its course from the observer’s sight, and then he may
ascertain its altitude to a much greater degree of accuracy 5
J should think, in such a.case, he will seldom be liable to
an error of more than five degrees, and in general will be
able to come nearer; but even where the surrounding ob-
jects are not so favourably situated, ¢hey will, if they hap~
pen to lie in the direction in w hich the meteor is seen, be
always found of great service in assisting the necessary ese
timates afterwards,

Those, therefore, who. have had an opportunity of ob=
serving a meteor, should, as soon as possible, repair to the
place where they stood when they saw it, and by means of
a-common or Gunter’s quadrant, or any other imstrument
that will measure altitudes, eadcavour to obtain its height
2s. correctly as they can ; and at the same time, with a
needle and -compasa, take its bearing at that .part of its
course where its.altitude was measured. jd. however, the
observer should not happen to be furnished with any imstru-
ments for ancasuring altitudes or bearings, yet if he has
been so fortunate as to have compared it with any fixt ob-
jeet, or has seen its course intercepted by the top of a house, a
eburch, or anyother body, and can recollect.the place where
he ktoad at thetime, its situation may be pretty correctly
ascertained ; for if he measures the distance from the place
where he stood to the object, and then measures the height
of the object behind which it disappeared, its altitude may
-be casily inferred; and by comparing the direction of such
abject with the porth apd santh, or-east and west, points,
its bearing at that.time will be had sufficiently near to be of
considerable service, as it is not necessary to be so correct
tn this respect as in obtaining its altitade, though the nearer
ave can come at both the better.

If the ebserver should happen te be in a ficld, or any
epen place where there are no neighbounng objects to assist
him in dis estimation, he will, however, be able to obtain
ats altitude and b earing, in the following manner: Lethim

,go to. the place where he stood when “he saw the meteor,
and there having fixed up a sod or stick perpendicular on
the ground, of a sufficient length, according to the height
at which the meteor appeared, let him recede from the

estick until, by looking over the top of it, he sce the top in
ahne with the place in which he before observed: the me-

‘teor to appear: if he then measures his distance from ae

stic 9

--seen November 13; 1803.» 283

stick, and the height of his eye from the level with the
bottom, and lastly the length of the stick, he will be able
to obtain its altitude pretty correctly ; and also, by observing
the direction the stick bears from him, will obtain at the
same time its azimuth. For this purpose the stick should
be chosen of such'a length that he may be able to recede
from it to the distance of six or eight fect at least. Many
people, however, who may have an opportunity of seeing
meteors and putting the above method in practice, for want
of mathematical information, may not be able to make the
necessary calculations ; but no loss will be sustained in this
case, provide such gentlemen would be careful to take their
measures as correctly as possible, and publish an account of
them, with a sketch of the method they made use of, which
would enable others to draw such conclusions as might be
necessary for their purpose, or at least be of great use to
them.

© The altitude and bearing at the time are the most neces-
sary to be known. The: apparent diameter, time of dura-
tion,, and extent of the track through which the phenome-
non ‘move may, however, be of great service when they
can be obtained with any tolerable degree of accuracy. But
here I must observe, that all estimations of altitudes with~
out instruments or any means of measuring are too falla-
cious to. be depended on, and can seldom or ever be ad-
mitted into computation. Let any one go out in the even-
ing, and endeavour to estimate the altitude of a star, or
any other object, and he will soon find himself liable to an
error of twenty or thirty degrees, generally estimating the
altitude too high. This I particularly instanced in the ap-
pearance of the meteor I have here described ; for, before I
measured its altitude with a quadrant, I had estimated it
fifteen or twenty degrees higher than it was. In ascertain-
ing the apparent magnitude of meteors it has been, I be-
lieve, the most usual way to compare their appearance with
that of the moon; and if the moon is visible at the time,
it will afford a pretty good object for that purpose but if
the moon should not be visible, it must be liable to a con-
siderable degree of uncertainty.

The apparent diameter of the meteor here mentioned I
have supposed to subtend an angle of not less than twenty
minutes of a degree, which, with the distance deduced from
the interval between the appearance of the meteor and hear-
ing the sound, gives its real diameter nearly 280 yards, or
almost half a mile in ¢ircumferénce ; and*also, by com-
paring the extent of track through which it moved with the

time

284 Account of New Publications.

time of its duration, its velocity will appear to have been
between seven and eight miles in a second :—a velocity
which more than twenty times exceeds the greatest velocity
of a cannon ball, and can only be compared to what we at
present know of the amazing velocity of electricity. »

In accounting for the nature and production of meteors,
it is evident that nothing can help us in our inquiries so
much as a knowledge of their dimensions, their distance,
and the extent of space through which they move; and
these are only to be obtained by good observations. » Al»
though their appearance and the manner in which they
burst are very curious, and should as much as possible be
observed, yet an attention to these eircumstances alone
_ are not sufficient to throw much light upon them, when

unassisted with any knowledge of their real situation and
dimensions,

XLIX. Account of New Publications,

A Treatise on the Culture and Management of Fruit-Trees,
in which a new Method of Pruning and Training is fully
described, CSc. Sc. By W. Forsyru, F, A, S, and
F.S. A. &c. &c. Third Edition. 8vo.

Tuts wotk is so well known to the public already that any
account of it from us would be superfluous. We only take
notice of the present edition for the purpose of mentioning
a new way of treating diseased trees, and to extract from it
a testimonial highly creditable to Mr. Forsyth,

** J avail myself of this opportunity (says Mr. F,) to add
a discovery which I have recently made, and which, as
being calculated to save time and labour, may deserve at-
tention.

“Instead of paring away the bark, as had heretofore
been the practice, and covering the stem with the compo-~
sition, I now merely scrape off the loose bark, and appl
a mixture of cow-dung and urine only (made to the cony
sistence of a thick paint) with a paintér’s brush, covering
the stem carefully over. This softens the old scabrous
bark, which peels off during the following winter and
spring, and is succeeded by a fine smooth new bark.”

“ To Mr. iorsyth, Royal Gardens, Kensington.
*¢ SIR,

* As you had the goodness lately to give us an oppore
tunity of examining several trees in Kensington gardens in

the

Philosophical Society, Glasgow. 285

the various stages of renovation, or filling up with new
wood; and as reports have been circulated, tending to dis-
eredit the efficacy of your process ;—we feel it an act of
justice, not only to you, but to the country, which is
deeply interested in your discoveries, thus publicly to de-
clare, that the statements you have published on the subject
eontain nothing more than the truth.

Joun Coaxtry Letrsom, M.D. F.R.S. &c.

Wititiam Woopvitte, M.D.*

JAMEs Sims, M.D.f

Wiir1am Norris. ft

JosepH Hart Myers, M.D.§

AsTLEY Coorer, ||

Epwarp CoLeman. §

H.N. Wituis, F.R.S. &c.”

London, Nov. 17,
1503,

‘

L. Proceedings of Learned and Economical Societies.

ROYAL INSTITUTION OF/GREAT BRITAIN.

Tue lectures for the ensuing season commenced on Thurs<
day the 22d of December, with a-course on Mechanics and
Physics, by Mr. Dalton. In the latter end 6f January the
other lectures and the public experiments of the Royal In~
stitution will beg: those on Chemistry by Mr. Davy, and
those on Natural Philosophy by Mr. Allen. The public
experiments will be made, partly in ihe lecture-room, and
partly in the new laboratory, which hasbeen fitted up so as
to accommodate 120 persons. The new library of refer-
ence is ina state of forwardness, and, it is hoped, will be
opened in the course of next month for the accommodation
of all the proprietors, life subscribers, and- annual sub-
scribers.
THE BOARD OF AGRICULTURE

Has offered the following Premiums :

I. Cottage.—To the person who shall build, and describe.
the board, the cheapest cottage, being at the same time
urable and comfortable, with not less than two room#

ie Physician to the Small-Pox and Inoculating Hospitals ; and author
of a work on Medical Botany.

+ President of the Medical Society of London.

} Surgeen to the Charter-House, &c

§ Physicien to the General Dispensary, Aldersgat:-strect.

|| Surgeon of Guy's Hospital.

@ Professor of the Veterinary College,

£36 Royat Institution of Great Britain; Fé.

above, and the same number below,—the gold medal: . Ae
plan, elevation, and account of the Ri arid expensey
verified by certificates, to be produced on or before the first
Tuesday in May, 1804: : :
II. Co¢tage.—To the persori who shall produce to the
board the model of the best and cheapest cottage, on a scale
of one inch toa foot; with estimates of the expense of
erecting’ it;—from five to ten guineas, according to merit.
To be produced to the board on or before the first Tuesday

in December, 1804.
[ To be continued. }

PHILOSOPHICAL SOCIETY, GLASGOW.

It is with much satisfaction we notice at any time new
institutions intended for the promotion of science and the
arts; for the tendency of all such institutions is to increase
the comforts of mankind. On the 9th of November this
society elected its office-bearers for the ensuing year, viz.

William Miekleham; L. L. D: Professor of Natural Phi-

losophy in the University of Glasgow, President.

John Robertson, esq. Vice-president.

Wm. Duncan, esq. Secretary.

John Lindsay, esq. Treasurer..

DIRECTORS.
Geo. M‘Intosh, esq. Mr. Peter Nicholsott,
Geo. Birkbeck, L.L.D. = Mr. John M‘Caulay,
James Monteath, esq. Mr. John Napier,
John Geddes, esq. Mr. Wm. Dun,

Alexander Drummond, esq. Mr. John Smith, -
Robertson Buchanan, esq. ‘Mr. Robert Hastic.

ee Se 2 eee ee eee a

~~ 2 “LI. Intelligence and Miscellaneous Articles.
VOYAGE OF DISCOVERY.

Extract of a Letter from Dr. Tivestus, Naturalist, be«
longing to the Russian Ships now on a Voyage of Discovery
round the World. ;

Santa Cruz, in the Island uf Teneriffy
: October a5, 2803.

I nave just returned from a tour to the bottom of the
peak. At this season of the year it is impossible to reach
the summit of it, for one half of it is covered with snow
and ice. I have, however, been well rewarded for the
fatigue I experienced in’ my laborious excursion. I have
made the most astonishing discoveries. In particular I have

oe 3 ' found

Poyage of Discovery. 23h

fourid an animal which has hitherto been considered as =
plant, because we were acquainted with it only in its dry
state. I have also seen mumuues found in caverns neat
St. André, and which mast have belonged to the former
inhabitants of the country. For three days past | have been
riding up and down the mountains. The sea shore at
Orotrava fas furnished me with several interesting objects,
as well as that of Poa, Sausal, and Santa Cruz. The
greatest number of new species 1 found among the sea
edge-hogs, sea stars, polypes, and other mollusca.

The soil of the island is entirely volcanic. There are
here a great many varieties of Java. The marquis of Cassi-
cahigal, the governor of the island, who resides at Santa
Cruz, received us with great kindness and hospitality, and
gaye us letters of recommendation to Orotrava.. He showed
us his two gardens at Santa Cruz, where we found many
rare plants, some of which our ambassador, M. Resanof
Samercyen requested for his imperial. majesty- The great
botanical garden, however, formed by the marquis de Nova,
who resides at Laguna, in this island, exceeded our expec-
tation; it was laid out in the year 1795, close to the town
of Orotrava. ‘lhe marquis sent tor an experienced gardener
from England, named Cornelius Macmanus. This intelli-
gent man amused us a whole forenoon with showing us
proofs of his industry; he is a good botanist and has studied
Linnzus: he makes frequent excursions fo the interior
parts of the country, and has already discovered several new
African species. . [I have written a catalogue of them. In
regard to the history of the. country I have collected some
excellent materials towards it: Ihave delineated an antient
unionument, and copied an inscription which relate to the
history of Teneriff.

The old Guanches, the former inhabitaats of the Canary
islands, whose mummies are still found sewed into sheep’s
skins, in holes of the rocks of mount Altobasso, Sausal,
and St. André, and. also in the Grand Canary are in
their original dress, each with a thigh bone in its hand,
and the head crowned with flowers ; they are clothed in the
‘skins of animals each at the side of its monument. At
the top of the monument stands the Santa Maria de Can-
dellera. I have also delineated several picturesque and re-
‘markable objects, such as Jandskips, dresses, towns, and
productions of the island, and constructed maps which
will be completed on my. return. The greater part of the
rarities L collected myself, and the productions of the peak
were given to me by the captain of an American ship, whe

; made

es Inoculation for the Vaceine and the Plagiie, &&c.

made a journey to the summit of the peak in the month of
August. We sailed from Falmouth on the 5th of October
and arrived here a few days ago. In four days at furthest
we shall proceed to Rio de Janerio, in Brazil, from which I
will write to you again.

INOCULATION FOR THE VACCINE AND THE PLAGUE.

E£xiract of « Letter from Dr. Dr Carroy of Vienna, toe
s Physician in London. —

Dr. Valli who tnoculated himself with the plague, in
order to try whether the vaccine is a preventative of that
tlisease, has, as appears, at length taken the plague, but it
is expected he will recover.

The question relating to dogs has not been resolved in a
manner favourable to the assertion of Dr. —, but as it
does not affect the principal point of the doctrins of the
vaccine inoculation it is of little importance, and the doctor
has written to me that he has not been fortunate in his zoo-
nomical researches. :

The question relative to the clavelée is now quite re-
solved, the cow-pock does not preserve sheep from future
infection, as the inoculated small-pox preserves then from
future variolic infection. The practice of clavelisation. is
now extending very widely. Some assert that they have
produced the cow-pock pustule on sheep, but hitherto no
experiments have proved that it is a preventative against
the clavelée. The celebrated and ingenious Dr. Sacco has
produced the cow-pock on most domestic animals, among
others sheep, and reproduced the disease in men and ani-
mals. Dr. Sacco has had the same success with equine as
with vaccine matter. I have no knowledge of the experi+
ment made in Ukraine which you mention. 1 imagine the
journalist alluded to has mistaken clavelisation for vacci-
mation.

PALLADIUM:
SIR, To Mr: Tilloch.

As it is said in orte of your Magazines that the riew metal
T have called palladium is not 2 new noble metal, as I have
said, but ari iniposition, and a compound of platina and quick-
silver, I hope you will do me justice in your next} and tell
your readers I promise a reward of twenty pounds to any
one that can make only twenty grains of real. palladium ;
and that the money is already in Mr. Forster’s hands, and
that I have begged Mr. Nicholson will name three proper
shemical gentlemen as umpires. P.

ee

P eso Tt

Ll. Chemical Examination of an antient Speculum. By
Professor KuApRoTH, of Berlin*®.

dwar the history of the antient metallurgy depends ona
proper explanation of the. different passages relating to it,
which .are to be found im antient authors, requires very
little proof, Though various men of learning who haye
made this point the particular object of their research have
collected these scattered fragments, and have endeayoured
to exhibit them in a more conspicuous point of view by ar-
tauging them in order, every thing belonging to this sub-
ject has not yet been properly cleared up; and, notwith-
standing the diligence of the old philologists, many cir-
cumstances are still left‘in a state of doubt and obscurity,
the cause of which seems chiefly to be the insufficiency of
the means employed for that purpose. On the other hand,
the critics and.antiquaries of the present day are in posses-
sion of many helps which were wanting to the former; and
in this respect chemistry and mineralogy may be considered
as of the greatest uulity when it is necessary to determine
the nature and-component parts of the antient metals.

Under a conviction that every contribution towards en-
Jarging our knowledge of these compositions is of consi-
deralle importance, I haye already directed my attention to
the numismatic part of the antient. metallurgy, and given
an account of the result of the experiments I made to de-
termine the alloys which the Greeks and Romans employed
for theirearlier coins ¢... The object of the present essay 1s,
the chemical examination of the metallic mass of an antient
speculum. When the wants of. mankind were increased
in consequence of their improved state of civilization, that
natural mirror the smooth surface of a piece of water was
no longer sufficient; artificial speculums which they might
always have at hand, and which they could use with more
convenience, became indispensably necessary. The only
materials which they could employ to construct them were
metals ; for.as soon as men kegan to work them they could
not help observing and turning to advantage their suscepti-
bility of a fine alah, which exhibited a distinct image of
such objects as were presented to them.

Ido not know whether there be any mention of metallic
mirrors earlier than that in Exod. c. xxxvili. v. 8., where

* From Scherer’s Allgemeines Yournal der Chemie, No» 33-
+ See page 256 of this volume.

Vor. XVIT. No. 68. T we
January 1804,

290 Chemical Examitation of an antient Speculunt.

we are told that the mirrors used by the Israelitish ladies at
their toilet were put in requisition by Moses, in order that
they might be cast into a large bason for washing the feet
of the priests. In our common German translation of the
Bible, no mention is made in this passage of mirrors; for
Luther translates it~‘* And he made the hand-bason of
brass, and its stand also of brass, in the presence of the
women who served before the door of the. tabernacle.”
Luther consequently has considered the word maroth in
the original as the plural of marah, which is deduced from
raah, and which therefore signifies, ‘in the sight of the wo-
men.” Luther, however, is the more inexcusable in this
passage, as the word maroth, a mirror, occurs in the Bible
only in this passage. The Septuagint, the Vulgate; the
English and Dutch Bibles, all, however, agree in transla-
ting Beramoth of the mirrors,” as being more correct : and
we find by Pliny * that the Pagan women, when attending
the worship of their deities, were ornamented with metallic
mirrors. Weare told also by Cyrillus Alexandrinus f that
the Israelitish women adopted the same custom, which they
borrowed from the Egyptians.

A passage in Job, c. xxxvil. v. 18, makes mentioit
also of the solidity of cast mirrors, But the authority of
this passage as a proof of the great antiquity of metallic
mirrors is much }essened by the doubts which some of the
modern critics entertain respecting the period when this
look was written: being considered as not older than the
time of Solomon, it is ascribed to that sovereign or to some
of his cotemporarics. Menard, in his Recherches sur les
Miroirs des Anciens, makes Cicero aScribe the invention of
metallic mirrors to Aisculapius: The first mirrors,” says
he, ** were of metal; and Cicero ascribes the vention to
the first Aisculapis.” But must it not appear singular that
#Esculapius, a deity who exerted himself so much for the
‘benefit of mankind, should be the inventor of mirrors ?
The passage of Cicero, translated by Menard, is to be found
in the treatise De Natura Deorum, and is as follows: Es=
culapiorum primus, Apollinis, quem Arcades colunt, qui
spectllum invenisse, primusque vulnus dicitur obligavisse.
‘But it may be readily seen that Menard has here committed.
a most egregious blunder, as he took the word specillum
which signifies a probe, for speculum which expresses a
mirror; and therefore was guilty of a more serious offence

by Lib Xxxill. cap. 9; lib. xxxiv. cap. 17. ‘
t Lib. ii. vol. i- p. 64, De Adoratione in Spiriru.
towards

Chemical Examination of dn dntient Speculum. 9291

towards the Roman consul, who certainly would not have
extolled at the same time the person who first bound up
wounds, and the inventor of that appetidage of the toilet
called a mirror.

In the earliest periods a mixture of cOpper and tin was
employed for the composition of mitrors. We are told by
Pliny that those manufactured at Bfundusium were consi-
dered as the best, but in the course of time a preference was
given to silver mirrors which weré made by an artist named
Prasiteles, who lived in the time of Pompey the Great.
That these consisted of hammered plates of pure silver ap-
pears from the following words: Lamina duct et specula
Jjieri non nisi ex optimo (argento) posse creditum fuerat.
The silver, however, was sometimes mixed with other me-
tals: Id quoque jam fraude corrumpitur. These silver mir-
rors were afterwards plated with gcld, im order to render
the image more distinct. This, at least, seems to appear
from the following passage, which, however is involved in
some obscurity: Nuper credit cwptum, certiorem imaginem
reddi auro opposito averso.

Mirrors in general formed part of thé household furni-
ture of the Roman ladies of the first rank. This is con-
firmed in particular by Seneca, who satyrizes the great ex-
tent to which the luxury of the apparatus of the toilet had
been carried among the female part of his fellow citizens.

What this excellent moral philosopher says in another
place * respecting the wise purpose for which mirrers might
be emploved is so beautiful that I cannot forbear quoting
it: Inventa sunt specula ut homo ipse se nosceret. Maulto
ex hoc consecuta, primo sui notitia, deinde et ad quedam
consilium. Formosus, ut vitaret infamiam: deformis, ut
sciret redimendum esse virtutibus quidquid corpori deesset :
juvenis, ut flore elatis admoneretur, illud tempus esse dis-
cendi: senex, ut indecora canus deponeret, et de morte ali+
guid cogitaret. Ad hoc rerum natura facultatem nolis de-
dit, nosmet-ipsos videndi. But for this purpose artificial
mirrors of great price were not necessary; as, fons cuique
pellucidus, aut leve saxwm, imaginem reddit. After ob-
serving that mirrors, in consequence of tlre increasing lux-
ury of mankind, had been applied to the worst purposes, to
gratify pride and voluptuousness, he adds, that they were
made of the full length of a man, covered with gold and
silver and set round with precious stones :—** One mirror
ef this kind,” says he, ‘* costs more to a lady than in for-

* Natural. Quast. lib.i, 17,
T@2 mer

292 Chemical Examination of an antient Speculwnt.

mer times the dowry giyen by poor generals to their daugli-
ters: the dowry which the senate gave to the daughter of
Scipio would not purchase at present a mirror for the daugh~
tcr of afreed-man.”” Borat cs WE Ne
Beckman, in his History of Inventions, is of opinior
that those mirrors. which were so large that people could
sce themselyes in them at full length were made of plates
of polished silver; for he observes, that to cast mirrors of
such a size from copper and tin, would require more art
than can be allowed to that period. ‘* I do not know,’’
adds he, ** whether our artists would succeed. in such am
operation.” But it appears more probable from the above
passage that the mirrors: m question were not of silver but
of iron, as Seneea says’ that they were covered with gold
and silver; but the covering with silver would haye beem
superfluous had the mirror itself been of that metal.
Though it evidently appears from Pliny and other au-
thors that the composition of nsirrors in general’ consisted
of a mixture of copper and tin, my late colleague M. Méh-
sen, in his Deseription of a Cabinet of Coms*, asserts. that
the union of these two metals was unknown to the antients ;
for he says, ‘* It is found by the examination. of ;antient
coins, made with ‘the severest tests, that before the time of
Septimius Severus none of the coins were mixed with lead
or with tin.”” That this assertion is unfounded has been fully
proved by my chemical experiments on this subject, which
I had the honour of laying before the Acadenay of Sciences.
Hitherto, however, it has not yet been determined by
certain analysis whether the component parts mentioned by
Pliny are contaiaed in the antient mirrors ;.and, if this be
the case, in what proportion. — A fragment of an antient
mirror found. with other antient vessels im a grave, af-
forded me an opportunity of examining it-chemiecally, and
of comparing my exptriments with those of Roux, the only
ones of the kind ever before made. Roux’s experiments
were made Gn an antient mirror found also at Naples, and
may be secnin the Recueil d’ Antiquités of count Caylus +.
The author describes the metallse mass as exceedingly brittle:
and tender, and of a white colour inclining to gray: when
put into the fire it continued a considerable time i a state
of ignition before it fused. It did not inflame, and neither
emitted an arsenical odour nor vapours of zinc. — So far this
description corresponds with that of the mass which f exa-
™ Beschreibung seiner Berlinischen Medaillen-Sammlung, part i-
p- 280.
“Part v. p. 174.
muned ;

Chemical Examination of an antient Speculum. 293

mined; but the component parts which [ found are gonsi-
derably different from these given by Roux; who thinks
that, besides copper and lead, he discovered also antimony :
on the other hand, he found no gine. . ,

Professor Beckman, in his History of Inventions, considers
it very probable that antimony was known. at that period,
and that it was employed in metallic compositions. He
therefore requested the opinion of M. Gmelin on this sub-
ject, and the latter informed him that it was not impro-
bable that the mass of the metallic mirror examined by Roux
might haye contained.antimony: he was not, however, con-
yinced that it contained no tin. ae

Qn the other hand, the results of my experiments gave
me, as the component parts of ‘the antient mirror, copper,
tin, and lead. i noe ae aha

The fragment subjected to analysis consisted of a me-
tallic plate, both sides of which were covered with.a flat
stratum of verdigris, composed of tender fibres,. arranged
concentrically in a radiated form, The.mass was compact,
very hard and brittle ; on the fracture, when fresh, of a
grayish white colour, and by polishing acquired the beauti-
‘ful splendour of a mirror. The specific gravity of the me-
tallic mass, when freed from the green rust, was to that of
distilled water as §580 to 1000. ‘Ye anigior

ist, A hundred grains of this mass being put to digest
with nitric acid, gave a blue solution, and -after repeated
diyestion left a whitish gray powder, which -weighed 39
grams. ee is g°

2d, The nitric solution being evaporated; to a small
quantity was subjected to-proof with a saturated solution
of muriate of soda, but no alteration was produced... The
mixture being then decomposed with sulphate of soda, it
became turbid: and. deposited a white heayy., precipitate,
which consisted,of sulphate of lead.. The whole quantity
i 4 when collected, was equal ta.@ grains of metallic

ead. . ° .
The copper was then precipitated from the solution by
iron. The whole quantity of the metallic copper consisted
pt 62 grains.’ at Si

4th, Muriatic acid being poured over the 39 grains left
by the nitric acid, the whole was exposed to slow digestion.
At gradually dissolved into a-clear fluid of a straw-colour.
{t was then diluted with three parts of water, and a rod of
zinc being immersed in it, metallic tin was by degrees de-
posited in a dendritic form, which when collected weighed
32 grains.

Ta A hun-

294 Chemical Examination of an antient Speculum.

_A hundred parts of the metal of this antient mirror con=
sisted therefore of

ye Grains.
Copper : - : 62
Tin - - - 32
Lead -s - - 6
100

From this analysis it appears that the antients, in the
composition of their mirrors, employed the same kind of
mixture as that used at present for the specula of tele-
scopes. The quantity of lead is here so small that it is
hardly worth notice, since it would produce no alteration
of any importance. Besides, it is probable that the lead
found in this case, did not belong to the formula of the
component parts, but arose merely from the adulteration
of the tin, as tin no doubt was sold at a much higher price
among the antients than it is among us. Pliny complains
of this adulteration of tin in the followiug passage (lib.
xxxvill. cap. 6.) : Plumlum candidum. That this expres-
sion means tin has been mentioned already—quod eri in«
coguelatur improbiores nigro temporabant. '

The proportion of the metals also in these antient mir-
rors corresponds nearly with that used at present for the
specula of telescopes, and consisted usually of two parts
copper, and one part of tin, oi

Our artists, however, are accustomed to employ other
metallic additions, such as silver, zinc, antimony, arsenic,
but these substances are added in so small quantities, that
they cannot be considered as essential to the composition :
the intention of adding them is partly to render the metal
more secure from rust, and partly to make the mixture
more fusible. It is with the latter view that arsenic is
added, and it in some measure answers the purpose.. The
antients, who were not acquainted with arsenic, could de-
riveno benefit from its quality of rendering metals more
fusible. ig Ne ik Sch

Metallic mirrors, since the invention of glass ones, have
been entirely disused as articles of furniture. Buta glass
mirror, properly speaking, is metallic ; for it is not the glass
but the amalgam of tin, placed at the back of it, which
reflects the image of the object presented to it.

LI. An

LIII. An Account of some Experiments and Olservations
on the constituent Parts of certain astringent Vegetables ;
and on their Operation in Tanning. By HUMPHREY
Davy, Esg., Professor of Chemistry in the Royal In-
stitution.

[Concluded from p. 217, ]

IV. Experiments and Olservations on the astringent Infue
sions of Barks, and other Vegetable Productions.

Tue parks that I examined were furnished me by my
friend Samuel Purkis, esq., of Brentford: they had been
collected in the proper season, and preserved with care.

In making the infusions, I employed the barks in coarse
powder ; and, to expedite the solution, a heat of from 100
to 120° Fahrenheit was applied.

The strongest infusions of the barks of the oak, of the
Leicester willow, and of the Spanish chestnut, were nearly
of the same specific gravity, 1-05. Their tastes were alike,
and strongly astringent; they all reddened litmus paper ;
the infusion of the Spanish chestnut bark producing the
highest tint, and that of the Leicester willow bark the
feeblest tint.

Two hundred grains of each of the infusions were sub-
mitted to evaporation; and in this process the infusion of
the oak bark furnished 17 grains of solid matter, that of
the Leicester willow about 164 grains, and that of the Spa-
nish chestnut nearly an equal quantity.

The tannin given by these solid matters was, in that from
the oak bark infusion, 14 grains, in that from the willow
bark infusion 14} grains, and in that from the Spanish
chestnut bark infusion 13 grains.

The residva} substances of the infusions of the Spanish
chestnut bark, and of the oak bark, slightly reddened litmus
paper, and precipitated the solutions of tin of a fawn colour
and those of iron black. The residual matter of the infu-
sion of the willow bark, did not perceptibly change the co-
lour of litmus ; but it precipitated the salts of iron of an
olive colour, and rendered turbid the solution of nitrate of
alumine.

The solid matters produced by the evaporation of the in-
fusions, gave, by incineration, only a very small quantity
of ashes, which could not have been more than 74,th of
their original weights, These ashes ¢ehiefly consisted of

T4 ' galeareous

£96 Experiments dnd Qbservations on the

calcareous earth and alkali; and the quantity was greatest
from the infusion of chestnut bark. ae,

The infusions were acted on by the acids and the pure
alkalis in a manner very similar to the infusion of galls.
With the solutions of carbonated alkalis they gave dense
fawn-coloured precipitates. ‘They were copiously precipi-
tated by the solutions of lime, of strontia, and of barytes ;
and, by lime water in excess, the infusions of oak and of
éhestnut bark seemed to be deprived of the wholé of the
vegetable matter they held in suhiaiba

By being boiled for some time with alumine, lime, and
magnesia, they became almost colourless, and lost their
power of acting upon gelatine and the saits of iron. After
being heated with carbonate of lime and carbonate of mag-
nesia, they were found deeper coloured than before; and,
though they had lost their power of acting on gelatine,
they still gave dense olive-coloured precipitates with the
salts of iron.

In all these cases the earths gained tints.of brown, more
or less intense. 5 on

When the compound of the astringent principles of the
infusion of oak bark with lime, procured by means of lime
water, was acted on by sulphuric acid,. a:solution was ob-
tained, which precipitated gelatine, and contained a portion
of the vegetable principles and a certain quantity of sulphate
of lime ; a solid fawn-coloured mattcr was likewise formed,
which appeared to be sulphate of lime united to a little
tannin and extractive matter *. - fp

The solutions were copiously precipitated by solution of
albumen. = °° | cu a

The precipitates they gave with. gelatine were similar in
their appearance ; their colour.at.first was a light tinge of
brown, but they. became very dark by exposure to the air.
heir composition: was -very nearly similar; and, judging
from the experiments on the quantity of gelatine employed
im forming them, the compound of tannin and gelatine
from the strongest infusion: of oak. bark seems to consist,

» * M, Merat Guillot proposes) a method of procuring pure tannin
(Annales de Chimic, tome xli. ps 325), which consists in precipitating a
solution of tan by lime water, and decomposing it by nitric or muriatic
acid, The salution of the solid -matter ebtained in this way in alcohol
he considers ‘as a solution ‘of pure ‘tannin; ‘but, from the experiments
above mentioned, it appears that it must contain, besides tannin, some of
the extractive matter of the bark; and it may likewise contain saline
matter,

Mt

constituent Parts of astringent Vegetables. 297

in the 100 parts,.of 59 parts of gelatine and 41 of tannin;
that from the infusion’ot Leicester willow bark, of 57 parts
of gelatine and 43 of tannin; and that from the infusion of
Spanish chestnut bark, of 61 parts of gelatine and 39 of
tannin. ; rf

Two pieces of calf-skin, which weighed when dry 120
grains each, were tanned ; one in the strongest infusion of
Leicester willow bark, and the other in the strongest infu-
sion of oak’bark. ‘The process was completed, in both in-
stances, in less than a fortnight; when the weight of the
leather formed by the tannin of the Leicester willow bark
was found equal to 161 grains, and that of the leather
formed by the infusion of oak bark was equal to 164
grains. ,

When pieces of skin were suffered to remain in small
quantities of the infusions of the oak bark, and of the Lei-
cester willow bark, till they were exhausted of their tanning
principle, it was found, that though the residual liquors
gave olive-coloured precipitates with the solutions of sul-
phate of iron, yet. they were scarcely rendered turbid by
solutions of muriate of tin; and there is every reason to
suppose that a portion of their extractive matter had been
taken up with the tannin by the skin. ‘
_ I attempted, in different modes, to obtain uncombined
gallic acid from the solid matter produced by the evapora-
tion of the barks, but without success. When portions of
this solid matter were exposed to the degree of heat that is
fequired for the production of gallic acid from Aleppo galls,
no crystals were formed; and the fluid that came over gave
only a brown colour to the solution ‘of salts of iron, and
ae found to contain much acetous acid and empyreumatic
' When pure water was made to act, in successive por-
tions, upon oak bark in coarse powder, till all its soluble
parts were taken up, the quantities of liquor last obtained,
though they did not act much upon solution of gelatine, or
perceptibly redden litmus paper, produced a dense black
with the solution of sulphate of iron: by evaporation, they
furnished a brown matter, of which a part was rendered
insoluble in water by the action of the atmosphere ; and the
part soluble in water was not in any degree taken up by sul~
phuric ether; so that, if it contained gallic acid, it was in a
state of intimate union with extractive matter.

Two pieces of calf-skin, which. weighed when dry 94
grains each, were slowly tanned; one by being exposed to
a weak infusion.of the Leicester willow bark, and the ae

T

#98 Experiments and Observations on the

by being acted upon by a weak infusion of oak bark. The
process was completed in about three months; and it was
found that one piece of skin had gained in weight 14 grains,
and the other piece about 164 grains. This increase is pro-
portionally much Jess than that which took place in the
experiment on the process of quick tanning. The colour
of the pieces of leather was deeper than that of the pieces
which had been quickly tanned; and, to judge from the
properties of the residual liquors, more of the extractive
matters of the barks had been combined with them.

The experiments of Mr. Biggin* have shown that si-
milar barks, when taken from trees at different seasons,
differ as to the quantities of tannin they contain; and I
have observed that the proportions of the astringent prin-
ciples in barks vary considerably according as their age and
size are different ; besides, these proportions are often in-
fluenced by accidental circumstances, so that it is extremely
difficult to ascertain their distinct relations to each other.

In every astringent bark, the interior white bark (that is,
the part next to the alburnum) contains the largest quantity
eftannin. The proportion of extractive matter is. generally
greatest in the middle or coloured part: but the epidermis
geldom furnishes either tannin or extractive matter.

The white cortical layers are comparatively most abun-
dant in young trees; and hence their barks contain, in the
game weight, alarger proportion of tannin than the barks of
old trees. In barks of the same kind, but of different ages,
which have been cut at the same season, the similar parts
contain always very nearly the same quantities of astringent
principles ; and the interior layers afford about equal por
tions of tannin.

An ounce of the white cortical layers of old oak bark,
furnished, by lixiviation and subsequent evaporation, 108
grains of solid matter; and of this, 72 grains were tannin,
An equal quantity of the white cortical layers of young oak
produced 111 grains of solid matter, of which 77 were pre-
' eipitated by gelatine.

An ounce of the interior part of the bark of the Spanish
chestnut gave 89 grains of solid matter, containing 63 grains
of tannin. (

The same quantity of the same part of the bark of the
Leicester willow produced 117 grains, of which 79 were
tannin.

An ounce of the coloured or external cortical layers from

* Philosophical Transactions for 1799, p. 299 h
the

=

constituent Parts of astringent Vegetables. 209

the oak, produced 43 grains of solid matter, of which 19
were tannin.

From the Spanish chestnut, 41 grains, of-which 14 were
tannin.

And, from the Leicester willow, 34 grains, of which 16
were tannin. :

In attempting to ascertain the relative quantities of tannin
in the different entire barks, I selected those specimens
which appeared similar with regard to the proportions of
the external and internal layers, and which were about the
average thickness of the barks commonly used in tanning,
namely, half an inch. :

Of these barks, the oak produced, jn the quantity of an
ounce, 61 grains of matter dissolved by water, of which
29 grains were tannin,

_The Spanish chestnut 53 grains, of which 21 were tan+
nin. .

And the Leicester willow 71 grains, of which 33 were
tannin. ’ i ;

The proportions of these quantities, in respect to the tan-
ning principle, are not very different from those estimated
in Mr. Biggin’s table *.

The residual substances obtained in the different experi-
ments differed considerably in their properties; but certam
portions of them were, in all instances, rendered insoluble
during the process of evaporation. The residuum of the
chestnut bark, as in the instance of the strongest infusion,
possessed slightly acid properties; but more than 3-4ths of

its weight consisted of extractive matter. All the residuums
in solution, as in the other cases, were precipitated by mu-
riate of tin; and, after this precipitation, the clear fluids
acted much more feebly than before on the salts of iron;
so that there is great reason for believing that the power of
astringent infusions to precipitate the salts of iron black, or
dark coloured, depends partly upon the agency of the ex~
tractive matters they contain, as well as upon that of the
tanning principle and gallic acid. —

Jn pursuing the experiments upon the different astringent
infusions, I examined the infusions of the bark of the elm -
and of the common willow. ‘These infusions were acted on
by re-agents in a manner exactly similar to the infusions of
the other barks: they were precipitated by the acids, by so-
jutions of the alkaline earths and of the carbonated alkalis :

* Philosophical Transactions for 1799, p. 263.
5

and

300 Experiments and Observations on the.

and they formed, with the caustic alkalis, fluids not, pre-
cipitable by gelatine. ae

An ounce of the bark of the elm furnished 13 grains of
tannin. ;

The same quantity. of the bark of the common willow

ve 11 grains.

The residual matter of the bark of the. elm contained a
considerable portion of mucilage, and that of the bark of
the willow a snzal! quantity of bitter principle.

The strongest infusions of the sumachs from Sicily and.
Malaga, agree with the infusions of barks in most of their
properties; but they differ from all the other astringent in-
fusions. that have been mentioned in one respect, they give
dense precipitates with the caustic alkalis. Mr, Proust has
shown that sumach contains abundance of sulphate of lime;
and it is probably to this substance that the peculiar effect
is owing.

From an ounce of Sicilian sumach I obtained 163 grains
of matter soluble in water, and of this matter 78 grains
were tanuin. AX ;

Ar ounce of Malaga sumach produced 156 grains of so-
Juble matter, of which 79 appeared to be tannin.

The infusion of myrobalans** from the East Indies, dif-
fered from the other astringent infusions chiefly by this cir-
cumstance, that it effervesced. with the carbonated alkalis ;
and it gave with them a dense. precipitate, that was. almost
immediately redissolved. After the tannin had. been preci-
pitated from it by gelatine, it. strongly reddened litmus
paper, and gave a bright black with the solutions of iron,
I expected to be able to procure gallic acid, by distillation,
from the myrobalans; but in this I was mistaken; they |
furnished only a pale yellow fluid; which gave merely a
‘slight olive tinge to solution of sulphate of iron.

Skin was speedily tanned in the infusion of the myroba~
Jans; and the appearance of the leather was similar to the
appearance of that from galls,

The strongest infusions of the teas are very similar, in
their agencies upon chemical tests, to the infusions of ca-
techu,

An ounce of Souchong tea produced 48 grains of tanmin.

The same quantity of ereen tea gave 41 grains,

- Dr. Maton has observed that very little tannin is found in
cinchona, or in the other barks supposed to. be possessed of

* The myrobalans used in these experiments are the fruit of the Tere
minalia Chebula.+-Retz. 04s, Botan, Fasc. v. p. 31
& 3 febrifuge

constituent Parts of astringent Vegetables. 308%

febrifuge properties. My experiments. tend to confirm the
observation. None of the infusions of the strongly bitter
vegetable substances that I have examined give any precipi-
tate to gelatine. And the infusions of quassia, of gen-
tian, of hops, and of camomile, are scarcely affected by
muriate of tin; so that they likewise contain very little ex-
tractive matter. — ,

In all substances possessed of the astringent taste, there
is great reason to suspect the presence of tannin; it even
exists in substances which contain sugar and vegetable
acids.. I have found it in abundance in the juice of sloes ;
and my friend Mr. Poole, of Stowey, has detected it in Port
wine. : .

V. General Observations.

Mr. Proust has supposed, in his Paper upon Tannin and
its Species *, that thete exist different species of the tanning
principle, possessed of different properties and different
powers of acting upon re-agents, but all precipitable by
gelatine. This opinion is sufficiently conformable to the
Jacts generally known concerning the nature of the sub-
stances which, are produced in erganized matter; but it
cannot be considered as proved, till the tannin in different,
vegetables has been examined in its pure or insulated state.
In all the vegetable infusions which have been subjected to
experiment, it exists in a state of union with other princi-
ples; and its properties must necessarily be modified by the
peculiar circumstances ofits combination. _

From the experiments that have been detailed it appears
that the specific agencies of tannin in all the different astrin-
gent infusions are the same. In every instance it is capa-
dle of entering into union with the acids, alkalis, and earths ;
and of forming insoluble compounds with gelatine and with
skim. The intusions of the barks affect the greater number
of re-agents in a manner similar to the infusion of galls;
aud that this last fluid is rendered green by the carbonated
alkalis, evidently depends upon the large proportion of galhie
acid it-contains. The infusion of sumach owes its charac-
teristic property, of being precipitated by the caustic alkalis,
to the presence of sulphate of lime; and that the solutions
of catechu do not copiously precipitate the carhonated al-
kalis, appears to depend upon their containing tannin in a
pecan state of union with extractive matter, and uncom-

iwed with gallic acid or earthy salts.

* Annales de Chimie, tome xii. p. 2492- .

In

30 Experiments and Olservations on the

In making some experiments upon the affinities of the
tanning principle, I found that all the earths were capable
of attracting it from the alkalis: and so great is their ten-
deucy to combine with it, that, by means of them, the com-
pound of tannin and gelatine may be decomposed without
much difficulty; for, after pure magnesia had been boiled
for a few hours with this substance diffused through water,
it became of a red brown colour, and the fluid obtained by
filtration produced a distinct precipitate with solution of
galls. The acids have Jess affinity for tannin than for gela-
tine; and, in cases where compounds of the acids and tan-
nin are acted on by solution of gelatine, an equilibrium of
affinity is established, in consequence of which, by far the
greatest quantity of tannin is carried down in the insoluble
combination. The different neutral salts have, compara-
tively, feeble powers of attraction for the tanning principle;
but that the precipitation they occasion in astringent solu-
tions is not simply owing to the circumstance of their uni-
ting to a portion of the water which held the vegetable sub-
stances in solution, is evident from many facts, besides
those which have been already stated. The solutions of
_aluni, and of some other salts which are less soluble in
water than tannin, produce, in many astringent infusions,
‘precipitates as copious as the more soluble saline matters ;
and sulphate of lime, and other earthy neutral compounds,
which are, comparatively speaking, insoluble in water,
speedily deprive them of their tanuing principle.

From the different facts that have been stated, it is evi-
dent that tannin may exist in a state of combination in dif-
ferent substances, in which its presence cannot be made
evident by means of solution of gelatine; and in this case,
to detect its existence, it is necessary to have recourse to
the action of the diluted acids.

In considering the relations of the different facts that
have been detailed, to the processes of tanning and of lea-
ther-making, it will appear sufficiently evident, that when
_ skin is tanned in astringent infusioris that contain, as well
4s tdrinin, extractive matters, portions of these matters
enter, with the tannin, into chemical combination with the
skin. In no case is there any reason to believe that gallic
acid is absorbed in this process; and M. Seguin’s ingenious
theory of the agency of this substance in producing the de-
oxygenation of skin, seems supported by no proofs. Even ~
in the formation of glue from skin; there 1s no evidence
which ought to induce us to suppose that it loses a portion
ef oxygen; and the effect appears to be owing merely to

the

constituent Parts of astringent Vegetables. 303

the separation of the gelatine, from the small quantity of
albumen with which it was combined in the organized form,
by the solvent powers of water.

The different qualities of leather made with the same
kind of skin, seem to depend very much upon the different
quanfities of extractive matter it contains. ‘Fhe leather
obtained by means of infusion of galls is generally found
harder, and more liable to crack, than the leather obtained
trom the infusions of barks; and, in all cases, it contains
a much larger proportion of tannin, and a smaller propor-
tion of extractive matter.

When skin is very slowly tanned in weak solutions of

the barks or of catechu, it combines with a considera-
ble proportion of extractive matter; and, in these cases,
though the increase of weight of the skin is comparatively
small, yet it is rendered perfectly insoluble in water; and
is found soft, and at the same time strong.
_ The saturated astringent infusions of barks contain much
less extractive matter, in proportion to their tannin, than
the weak infusions; and, when skin is quickly tanned in
them, common experience shows that it produces leather
less durable than the leather slowly formed.

_ Besides, in the case of quick tanning by means of infu-
sions of barks, a quantity of vegetable extractive matter is
lost to the manufacturer, which might have been made to
enter into the composition of his leather. These observa~
tions show that there is some foundation for the vulgar
opinion of workmen concerning what is technically called
the feeding of leather in the slow method of tanning ; and,
though the processes of the art may in some cases be pro-
tracted for an unnecessary length of time, yet in general
they appear to have arrived, in consequence of repeated
practical experiments, at a degree of perfection which can
not be very far extended by means of any elucidations of
theory that have as yet been made known.

On the first view it appears singular that, in those cases
of tanning where extractive matter forms a certain portion
‘of the leather, the increase of weight is less than when the
‘skin is combined with pure tannin; but the fact is easily
accounted for, when we consider that the attraction of skin
for tannin must be probably weakened by its union with
extractive matter; and, whether we suppose that the tannin
and extractive matter enter together into combination with
the matter of skin, or unite with separate portions of it,
still, in either case, the primary attraction of tannin for skin
must be, to a certain extent, diminished,

In

$04 On the constituent Parts of astringent Vegetables.

In examining astringent vegetables in relation to their
powers of tanning skin, it is necessary to take into account,
not only the quantity they contain of the substance preci-
pitable by gelatine, but likewise the quantity and the na-
ture of the extractive matter; and, in cases of comparison,
it is essential to employ infusions of the same degree of con-
eentration. — ‘

It is evident from the experiments detailed in the third
section, that of all the astringent substances which ‘have
been as yet examined, ‘catechu is that which contains the
largest proportion of tannin; and-in supposing, according
to the common estimation, that from four to five pounds of
common oak bark are required to produce one pound of
deather, it appears, from the various’ synthetical experi-
ments, that about half a pound of eatechu would answer
the same purpose *.

Also, allowing for the difference in the composition of
the different kinds of leather, it appears, from the general
detail-of facts, that one pound of catechu, for the common
uses of the tanner, would be nearly equal in value to 24
pounds of galls, to 74 pounds of the bark of the Leicester
willow, to 11 pounds of the bark of the Spanish chestnut,
to 18 pounds of the bark of the elm, to 21 pounds of the’
bark of the common willow, and to 3 pounds of sumach. |

Various menstruums haye been proposed for the purpose
ef expediting and improving the process of tanning, and,
amongst them, lime water and the solutions of pearl-ash :
but, as these two substances form compounds with tannin
which are not decomposable by gelatine, it follows. that
their effects must be highly pernicious; and there is very
little reason to suppose that any bodies will be found which,
at the same time that they increase the solubility of tannin .
m water, will not likewise diminish its attraction for
skin, .

* This estimation agrees very well with the experiments lately made
by Mr, Purkis upon the tanning powers of Bombay catechu in the pro-
cesses of manufacture, and which he has permitted me to mention. Mr-
Purkis found, by the results of different accurate experiments, that one
pound of catechu was cquivalent to seven or eight of oak bark,

: LIV. Letter

1 305) 7

LIV. Leiter from J. Hume, Esq. on the Formation of
Nitrous Ether, by Means of Nitrate of Mercury, and on
other Discoveries supposed to be modern,

~ DEAR SIR, To Mr: Tilloch.

F ROM reading a paper which appeared in a late number of
the Philosophical Magazine, I am induced to conclude
that the process for obtaining nitrous ether, by means of
nitrate of mercury and alcohol, published above forty years
ago, is not so generally known as it deserves ; it is, there-
fore, but fair, in order to do justice to its author, to take
the most effectual method to assert thé priority, by referring
to the work itself; and that I may more certainly gain your
concurrence to give an early insertion to this communica-
tion, I shall be as brief as possible.

I know not the exact period when the work to which I
allude was published, as there is no date affixed; but as
the author speaks of several of his contemporaries, particu-
larly of the celebrated anatomist Cheseldeh, it must have
been written at least forty years ago—the title is ‘* Mis-
cellanea vere utilia.”

From some particular expressions of the author I am
inclined to believe that, without bis being aware of it, he
was in possession of the fulminating mercury; for his at-
tention seems to have been chiefly absorbed in the forma-
tion of the ether, or, as he terms it “ a spirit prodigiously
volatile,” and, consequently was not so much, if at all,
applied to investigate the powder or milky ” appearance
in the mixed fluids; which has since been proved to be the
most important, or rather wondetful, part of the produce.

I suspect, were we industrious enough to search for
them, that many of what are stated to be the modern dis-
coveries were well known to, and probably described by,
our ancestors. An instance of this; amongst others, has
lately occurred to me, viz. a chemical lamp, in all respects
similar to Argand’s, but with ¢wo concentric wicks; the
invention of this is said to be of very modern date, and is
ascribed to Webster. I have now in my possession a lamp
of this description, made more than twelve years ago, for
it was then bought by an eminent brass-founder in Hart-
street, Covent-garden, as old metal. From its magni-
tude it must have been employed ina light-house. It has
two concentric wicks attached to a single rack, which are

Vou. XVII. No. 68, U moved

“306 ‘A Method of affording Relief

moved by a small pinion, in the ordinary way; the dianie«
ter of the interior wick is 0-9 of an inch; the other meas
sures 3 inches, and the whole seems to be made of brass.
Long Acre, I remain, dear Sir,
Jan. 14 1804. With much esteem, yours,
J. Hume,

LY. Method of affording Relief to Persons injured by y
Lightning. Communicated in a Letter from Mr. sata
GILeERT to the Rev. Mr. STEELE*.

Haine bh heard by common report that the house of Mr.
Martin, of Augusta, was struck with lightning on the night
of the 25th of June 1803 ; 3 and that he and his wife were
much injured by the shock ; and that by some means or other
they were relieved, but could not learn how, | sent to
them, requesting them to write to me a statement of the
facts which attended that eyent with as much precision as.
possible. In due time I received a letter from Mr. Gilbert,
who is father-in-law to Mr. Martin, in which he wrote as
follows :— ~~~

“‘ On the ight of the 25th of June. the house of Mr.
Wm. Martin was struck with lightning at the north ridge.
ft shivered the stud which stood directly under the ridge,
rent the boards at the gable-end, entered, the room where.
Mr. Martin and his w ife w ere asleep, and dashed a looking.
glass to pieces’ which hung at the foot of the bed. The
lightaing’ passed, from where the looking-glass hung in a
direction to the axis. , Mrs. Martin was affected across her
loins; and’ ‘particularly her right arm; the other arm also
was affected, but-in aless ‘degree. “Mr. Martin was affected
in his head and shoulders : they were both asleep. A child
which lay oh the back side of ‘the bed, itis supposed, was
awakened by the thander, and, being greatly frightened,
cried owt, This awakened Mis. Martin, and she found
herself in a situation in which'she was unable to move her
limbs ;-but after two or three exertions she rolled herself
of the bed, and then discovered the curtain over her head
to be on fire. Befgre she got off the bed she discovered
that her husband. was speec chless and senseless. When she
had got off the’bed to the floor, and the child also, she
crawled to the foreside of the bed. Here, on the floor,

**-From.the New York Advertiser.

j ki the

to Persons injured by Lightning. 307
the water stood a small depth, being driven in.at the door:
upon putting her right hand, which was most affected,
intu the water, she felt immediate relief. Her arm and
hand remained weak ; but the insensibility and numbness
were immediately taken away. By some extraordinary
effort she now dragged her husband off the bed to the floor,
but how shé did this she cannot relate—and_ wonderful
indeed it is, for she liad not strength to stand upon her
feet, She had called her two little sons, who slept in the
chamber, and, having experienced relief from putting her
hand into the water, as mentioned above, she ordered the
oldest to fetch a bucket of water and to pour it on his
father, which he did. This he repeated until Mr. Martin
began to move, and raised himself on his hands and knees.
The little boy then came in with the fifth bucket of water,
which his mother ordered him to pour on his father’s head.
This he did, and then Mr. Martin got up and stood upon,
his feet, and, with wildness in his countenance, cried out,
© What are you doing?’ . Mrs. Martin informed him the
were struck with lightning, and showed how the bed-clothes
were burnt: he then became composed. He remained,
however, in great pain in his head, neck, and shoulders,
which continued for several days, but by degrees went offs

<< Tt appears that the lightning, after going in the di-
rection mentioned above, took a contrary course, being
attracted, as it 1s supposed by a carpenter’s iron square,
which hung oyer a chest with drawers, standing on the side
of the room opposite to the bed: it fell from the square on
the chest and gouged out a piece near the bottom. In a
drawer of the chest were some pewter spoons, on each of
which a drop was melted, as if touched with a hot irons
In the same manner were marked two or three plates which
stood on a shelf by the chest. ©

“© These, Sir, are the particulars of that affecting scene,
as nearly as I can recollect them, but incorrectly written.
They are submitted to your perusal and for your use, as
you think proper.”

LVI. Extracts from the Third Volume of the Analyses
. of M. Knaprorn.

[ Continued from p. 243. ]
Analysis of Fossil Elastic Resin,
Wisteuak elastic resin extracted from the lead ore of

Odin near Castletown in Derbyshire, or the fossil caout-
Ve2 chouc,

¢

808 Extracts from the third Volume of

chouc, possesses a remarkable property, from which it
derives its name, and which distinguishes it in an eminent
degree from all other combustible minerals. Messrs. Hat-
ehett and Scherer have described fifteen varieties of it; the
first of which are still impregnated in part with fluid oil of
petroleum, and the Jatter have a resemblance to asphaltum,
completely hard and brittle, while the intermediate varieties
possess more of less the elastic property. We must still
distinguish a new kind, found a few years ago in a small

‘river situated near that mine, which differs trom the pre-
ceding by a: more spongy elasticity, and by other proper
ties. It approaches to the nature of cork, and Mr.
Hatchett found five varieties of it.

Ist, The fossil elastic resin, in compact fragments,
greenish brown olive, which, when looked through towards
the light, is transparent, and appears of a bright red hya-
cinth colour. This fossil is soft, exceedingly elastic, and
adheres to the fingers.

2d, Dark brown fossil elastic resin, which has for gangue
crystals of sparry gray swinestone.

3d, Yellow and red bright hyacinth, inclosed nr small
masses in groups of sparry calcareous fluor.

4th, Duil reddish brown, of a spongy, or cork~like tex
ture; containing blackish gray nuclei of impure caout-
ewhouc.

The caoutchouc subjected to experiment by M. Klaproth
was the first variety of this new species. This fossil is one
of those bodies the analysis of which can be effected only
in the dry way; and, consequently, the immediate princi-
ples of it cannot be extracted.

Exp. 1. Fossil caoutchoue resists, in general, the ac-
tion of all fluid solvents. The one which appears to have
any is rectified oil of petroleum. Fragments of fossil
caoutchouc, immersed in this oil, were at the end of some
days swelled up a little and more transparent. The oil,
which was colourless, had acquired a bright yellow colour.

The-red vapours of fuming nitric acid, poured over an-
other part of caoutchouc, heated in a sand bath, soon gave.
place to white vapours of ‘nitric acid, which were disen-
gaged till it was almost entirely evaporated ; which proves
that there was no reciprocal action between the fossil and
the acid. The resin, when washed; showed no sensible
mark of alteration.

The action of alkalies is as ineffectual as that of acids.
Sixteen parts of concentrated solution of potash, boiled for
some time with one part of this elastic resin till it almost

acquired

the Analyses of M. Klaproth. 309

acquired a thick consistence, produced in it no alteration.
It retained the same characters of elasticity, consistence,
and colour.

Exp. Il. M, Klaproth kindled one part of elastic resin,
and miade it burn till it dissolved into black drops. In this
state the fossi] had not entirely lost its elasticity, It was
still of a pitchy and clammy nature, and could be drawn
out into threads between the fingers. This iniperfect com-
bustion, however, rendered it soluble in oils, and particu-
larly in that of petroleum, to which it communicated a
black colour.

Exp. UI. Two hundred grains of pure elastic resin,
placed on a sand bath in a small glass retort, communi-
eating with a pneumatic mercurial apparatus, gave by di-
stillation, which required a pretty strong and well-main-
tained fire, the following products :

ist, Eighty-four cubic inches of gas, which had a fetid
odour of garlic. This gas, agitated in water, lost eight
cubic inches of carbonic acid, which precipitated lime-wa-
ter, and the remaining 76 cubic inches of carbonated hy-
drogen gas burned with a brilliant flame.

ad, One hundred eighty-six grains of a brown fluid oil
ofadisagreeable odour.

3d, Three grains only of a slightly acidulous water ; the
small quantity of this acid did not permit M,. Klaproth to
examine the nature of it, Yi

4th, The porous carbonaceous residuum, which had a
somewhat metallic splendour, weighed 24 grains.

5th, When calcined in a capsule, it left 13 grains of
reddish brown ashes, which, when moistened with a little
water, gave a red tint to blue turnsole paper, which in all
probability was owing to the caustic lime it contained.
When put to digest in muriatic acid there remained
44 grains. of a light gray earth, mixed with a little char-
coal, which, by calcination, was reduced to three grains
of pure silex. The sym total of the charcoal consumed,
amounted, therefore, to 124 grains,

6th, The muriatic solution, concentrated by evaporation,

‘and edulcorated with alcohol, deposited a grain ot crystal-

lized sulphate of lime. When diluted with a larger quan-
tity of water, it gaye by solution of succinate of ammonia,
a reddish precipitate, which, by calcination, was reduced
to 14 oxide of iron. The remaining solution, neutralized by
that of caustic ammonia, deposited by the addition of car-
bonate of ammonia half a grain of alumine, and 74 grains
of carbonate of lime, equivalent to 4 grains of caustic lime,

U3 A hundred

310 Extracts from the third Volume of
~ A hundred parts of elastic resin, analyzed in the dry way,
were therefore decomposed into : '

Carbonated hydrogen 38 cubic inches

Carbonic acid -. - - 4 do.
Bituminous olf = Ss + —s = ~—Ss 73. grains.
Acidulous phlegm ~ - 1°50
Charcoal | - - - 6°25
Lime - - ~ . 2
Silex AD het eaete alge 1°50
Oxide ofiron - - - 0°75
Sulphate of lime 0S 0°50
Alumine . = - - 0°25

of which, however, the. five last. only are immediate prin
ciples of the fossil caoutchouc, while. the other five exhibit
products of the natural combination of the carbon, hydro~
gen, and oxygen contained in this fossil, but altered by;
the Grey 4" pads” os ;

Nothing is found in the results.of this analysis which can,
throw.any light onthe explanation of the elastic property
possessed by this singular fossil: we must, therefore, ad~
here to the opinion of Mr. Hatchett, who ascribes it to
small molecule of air, interposed in, the pores of the resin,
accumulated during its formation ina manner stil un~
known,. and.which communicates to its whole mass an
clastic and spongy consistence.

- Analysis of. Peat. Earth (tourbe).

Peat earth, formerly denoted by the name of ligneous:
earth, bituminous earth, is'dug up in great abundance in
the county of Mansfield,:and in the circle of Saal, where’
it is found in considerable strata, almost always at a little
depth below the vegetable earth. “It has’a blackish colour,:
and an earthy fracture. It communicates a little tint to
bodies on which it is rubbed. It is.dull, easily pulverised,’
and in. the air fails -almost-into'‘dust, It is a very useful’
combustible, which is prepared by softening it in water,
moulding it like bricks in wooden moulds, and then’ leaving’
it, to-dry in the airy’. °2 "e+

Its appearance and*teX%ture prove that it has originally-
formed the fibrous part’ of a large quantity of wood, depo~'
sited’ by water, which’ has become altered in its immediate
principles, but which has not ‘entirely lost its structure.

The peat earth employed in the following analysis was
dug up in the royal bailiwick of Schraplace.

Lap. 1, Two: hundied grains of this fossil, put ae a

- algge [-% , + 3 ass °

- X _

«the Analyses of MORlaproths a

gisss retort brought ‘to’ a red-heat, :and: which*communi=
¢ated with a mercurial apparatus, gave for products:
ist; One hundred thirty-five cubic inches’ of elastic fluid
(allowance being made'for ‘the air contained in the retort
and the tube of communication), composed of 17 of car-
bonic acid gas absorbed by lime water, and 118 of car
bonated hydrogen gas. meee
ad, Twenty-four grains of acidulous’ water. As the
fossil when: boiled in water communicates to it-no aci+
dity, this acidulous phlegmt is therefore “a product of the
distillation, and ‘probably composed of pyroligneous. acid
{empyreumatic acetous acid). ine) / phahdiles:
3d, Sixty grains of a brown, clear, fixed oil, which had:
a taste only slightly empyreumatic, and sic resemblance te
Sitaatinolitors. fond! raterus Fie ee, 2
4th, The carbonaceous residuum taken front the retort
tveighed 774 grains. Wher burnt ina’ capsule they were

reduced to’37 grains of ight brown ashes, mixed with grains
of sand: the charcoal had consequently lost 403 ovains.
5th, Water boiled over the ashes, and then filtered, gave
a slight tint of red to’ blue turmsole paper: it left by evapo-
ration sulphate of lime, which, when roasted, weighed 5
grains. A small quantity of free caustic lime had’restored:
the blue colour of the red turnsole paper. :
- 6th, The lixiviated ashes being dissolved in nitro-muri-.
atic acid, the insoluble sandy’ residtttm weighed 23 grains.
7th, The caustic solution of ammonia produced shy it &
cre brown deposit, from which were extracted by caustic
alkalies, two grains of the oxide ‘of iron. and one grain of
dluinimes > *5 Ope 0 AR TPES? Bae STR 8
sth, The rest’ of thé solution, by carbonate of potash,”
dave carbonate of lime, which by calcihation was reduced’
to’four grains of purelime Ys :
. Exp. Il. Alcohol, put to digest on’peat earth, extracted
from it’a reddish brown’ tincture; which by evaporation
was thickenéd into a reddish dark brown extract, the taste
of which was very bitter, without’ being disagréeable, and
approached near to that of an extract trom the common
kinds of ‘cinchona. It dissolved only. imperfecly in water,
which it rendered turbid. ee
Exp. U1.» Four ounces of peat’ earth,’ boiled at thre¢
different times with water, gave a clear reddish brown dé
eo¢tion, in no manner either acid or alkaline. Evaporated
in a gentle heat it left a-dry pulverulent extract, of a
walnut colour, weighing 145 grains, haying the same taste,
but less bitter than the preceding. “A simi
iately

312 Extracts from the Analyses of M. Klaproth,

diately dissolved it. The liquor was clear and of a dark
brown colour, but it suffered to be precipitated at the same
time a yellowish white deposit, composed of sulphate of
lime, which when dried weighed 39 grains.

M. Klaproth tried to effect several combinations with the
solution of this extract.

ist, It remained clear, and experienced no change of
colour when mixed with solutions of animal glue, alkaline
salts, alum, nitrate of lime, sulphate of copper, and sul-
phate of iron recently oyatnlliaed.

2d, But it was decomposed by barytes water. Solutions
of muriate of barytes and zinc, of nitrate of silver and of
mercyry, of acetite of lead, of hyper-pxidated muriate of
iron, &c. produced in it flaky deposits of alight brown
wood colour; and the supernatant liquor became almost
always colourless. .

Exp. 1V. The combustible part of peat seemed to dis~
solve almost entirely when put to digest ina highly con-
centrated alkaline ley. When diluted with from 12 te
16 parts of water and filtered, the water still retained a
dark brown colour, inclining to black, When saturated
with the sulphuric or nitric acid, it becomes brightened,
and assumes a reddish brown colour. It precipitates by
heat a voluminous brown deposit, which, when collected
by the filter and washed, dries by heat into large, black,
very brilliant grains, and which, when afterwards roasted
jn a capsule, leaves yellow ashes. .

Exp. V. Two ounges of oil, obtained by the distillation
of a larger quantity of peat earth, rectified in a retort with
a gentle heat, in a sand bath, and of which 14 ounce was
distilled, left a blackish gray residuum, which, on cooling,
acquired the consistence of wax. The distilled oj] was of
a honey yellow colour, and became fixed in foliated cry~
stale, The most fluid of the oily part of these crystals,
imbibed by blotting paper, over which they had been
spread, left them deposited there in scales or small leaves,
éasy to be separated, brilliant, and of a light hrown colour.

When this oil is heated on a moderate charcoal fire, un-~
ti] the aqueous moisture is in a great measure evaporated,
it acquires, by cooling, the consistence of soft cerat. In
this state it has a great resemblance to the maltha, or cire~
des-saes of Siberia*, = 7
Fr idea Oil

* The cire-des-saes, or maltha, is brought from the lake Baikal, on
the banks of whith it is extracted, near Bargusin. M. Klaproth ob-
serves, that the classification of this natural wax among the bituminous

igh mia en Pe ae substanceg

‘Analysis of the Human Teeth. 313

Oil of peat dissolves in abundance in alcohol, by means
of digestion. This solution, which is clear, becomes fixed .

by cooling. Maltha with alcohol exhibits the same phe~
nomena,’

LVII. Analysis of the Human Teeth. By W.H. Pepys

jun. Esq. P.R.I., Member of the Askesian and British
Mineralogical Societies *.

Mz. Cnartes Harcuert, in his valuable paper on shell
and bone, (Philosophical Transactions for 17995) enume~
rated the several substances which enter into the composi-
tion of the human teeth: it is to be regretted that the na-
ture of his subject did not render it necessary for him te
ascertain the proportions in which they are respectively
found, as it could not have failed to have proved highly
useful, and his known accuracy would have precluded the
necessity of any other person undertaking such a labour.
Several good analyses of bone haye been published, but f
belicve no accurate analysis of the teeth has yet been of;
fered. .
* Bone, it has been observed, when exposed to the action
of acid menstrua, becomes dissolved; that is to say, the
solid or constituent substance of them is abstracted, and a
gelatinous matter is left of the form of the original bone.

Nitric, muriatic, and acetic acids are capable of pro-
ducing this change, which is accompanied with a liberation
of an aériform fluid, that precipitates lime in lime water,
changes vegetable blues red, and by its gravity is known
to be carbonic acid gas. These acid solutions yield a co-

ious precipitate with pure ammonia, which is again solu-
ble in either of the acids. After the precipitation by pure
aminonia, the solution of the carbonate of ammonia will
still produce a new precipitate,

The precipitate of the first solution by pure ammonia,
as noticed aboye, is soluble again in the acids before men-

substances appears to him improper in various respects. Might not
inaltha be the product also of the distillation of a similar kind of turf
effected by nature? As that which forms the subject of the preceding
analysis can no longer be classed among the bituminous fossils, both on
account of its chemical principles and of its mineralogical characters,
its old definition of bituminous ligncous earth can no longer be applied
t@ it. ;

* From a recent interesting publication, Tbe Natural History of the
Human Teeth, by Joseph Fox. :
g 5 tioneds

314 Analysis of the Human Teeth.

tioned: these solutions yield, with 2 solution of acetite of
lead, a copious precipitate, proving the presence of phos-=
phoric acid. x iy vik

The precipitate obtained by the carbonate of ammonia is
also soluble in either of the above acids, but with efferves-
cence; and-these solutions are not precipitated by acetite
of lead; they fall, however, with oxalate of ammonia, carr
bonate of ammonia, or any precipitant of lime.

The great solubility of the phosphate of lime, in even the
weakest of the acids, is very extraordinary. Phosphate of
Time meclianically suspended in water is speedily and com>
pletely dissolved by passing a copious stream of carbonic
acid’ gas through it...”

With these facts before me, F have ventured to examine
the several specimens of the human teeth; as the enamel,
the bone, or roots, the teeth of adults, and the shedding
teeth of children.

Previous to an account of the analysis it may not be un-
interesting to notice the action of some of the articles of the
materia chemica on the teeth.

Sulphuric acid of the specific gravity 1°83 appears at first
to have no‘action ; im the course of an hour small bubbles
are: perceived, the roots become blackened, and.in twelve
hours the enamelled part bursts, cracks, and separates, ac-
companied with an evident formation of selenite, by the
actién of the acid on the lime, which enters into the com-
position of the teeth.

Nitric and muriatic acids of the specific gravity of 1-12
act instantly on the tooth, accompanied witl an evolutton
ef a quantity of small air-bubbles from the whole of the sur-
face: about eight times their weight of these acids are suffi-
eient for the solution of the solidifying principles of the
teeth. The mass left undissolved has nearly the original
form of the tooth, is flexible, semitransparent, and easily
divided by the nail, .

The dilute acetous acid (distilled vinegar) has a very tri<
fling action, but, when concentrated, acts both on the phos-
phate and carbonate of lime.

Boiling nitric acid acts strongly on atooth with the evo-
ation of carbonic acid and a considerable quantity of azotic
gas. The gelatine and solid substance are dissolved as the
surfaces present themselves; but the operation being stopped
at any part of the process, the residuum is firm and hard,
but reduced im size proportioned to the time the tooth has
been acted upon.

> Analysis

Analysis of. the Luman Teeth. 31s
Analysis of the Enamel.

One hundred grains of the enamel of human teeth, care-
fully rasped, were’ placed in 600 grains of nitric acid of the
specific gravity 1°12. Slight effervescence ensued, and after
twelve hours 200 grains more of the acid were added. Al-
lowing for the loss by eyaporation in.a corresponding vessel,
after thirty-six hous it was found to have lost four grains
and a half. i
It was then diluted with four ounces of distilled water,
precipitated by pure-anmmonia, ,and then filtered... ..
The precipitate obtained being dried’ in a water-bath at
212° weighed 102 grains. It was then ignited, after which
it was found to weigh 78 grains. ra
The filteréd solution was then precipitated by carbonate
of ammonia in solution, and filtered. ’
The separated precipitate, being dried in,a, heat of 2127
aveighed six grains, Enamel, then, consists of —
Phosphate of lime - - 78
Carbonate of lime vs > 6
~ ‘ 84 F ey
‘Water’of composition;.and loss =. 16

——s

>

100.

A loss of 16 grains here takes place, which is easily ac-
counted for, ftom the impossibility of directly ascertaining
the state of dryness in which the ingredients existed origi-
nally in the enamel’; for we have seen that, by drying the
phosphate’of lime in a heat of 212°, (after which it had the
appearance of being as dry as possible,) it yet contained so
much moisture as to yield a gain of eight grains in the
analysis,’ 5 ; Tee 4

On the other hand, when ignited its state is-driyven,to;
the opposite extreme, and there is a loss of 16 grains, It.
is umpossible, however, that the materials could exist in the
tecth, in a state of dryness to he compared with that_pro-
duced by exposing them to such a high temperature. And.
it appears but reasonable to, conclude, that the real quantity
of moisture lies nearer’ to that given by the heat of 212°.
than to that given by ignition, and consequently that the
16 grains lost by exposure to such a high temperature were
¢hicfly water, —

Bone,

316 Analysis of the Human Teeth,

Bone, or roots of teeth, yielded by analysis in 100 grains,
Phosphate of lime - - 58
Carbonate of lime -
Gelatine - -

90

Water of composition, and loss - 10
100

The teeth of adults yielded on analysis in 100 grains,
Phosphate of lime - - 4

Carbonate of lime - - 6
Gelatine - i es = 20
90

Water of composition, and loss ~ 10
100

Specific gravity of adults’ teeth 9°2727.

The shedding or primary teeth of children, yielded on
analysis in 100 grains,

Phosphate of lime - - 62
Carbonate of lime - - 6
Gelatine - - 2 20

88

Waiter of composition, and loss + 12

100

ed

Speeific gravity of children’s teeth 2°0833.

In these analyses, as in the former, the phosphate of
lime ‘was also exposed to a red heat, and consequently was
reduced to a greater degree of dryness than that in which
it existed in the tooth.

Tn all of them the carbonate of lime was dried in a heat
of 212°, (above which it would have been liable to decom-

position), and the gelatine of the three last in the same
temperature,

LVIII. On

f 817 ]-

LYIII. On Sharks. By Wixt1am Tatuam, Esq:
SIR, To Mr. Tilloch.

Ossdavine in a shop window a print representing an ac~
cident which happened from the voracity of a shark in the
harbour of Havannah, in the island of Cuba; and having
frequently noticed the propensity of the vulgar to swallow
extraordinary instances as matters of general existence (be-
lieving all the western hemisphere to be overrun with mon-
sters and savages, because geographers have, in some in~
stances, thought fit to ornament their productions with
Indians, bears, and snakes, with hideous creatures and
wild ferocity) ; it may not be unpleasant to communicate
to you a fact or two, within my own knowledge, touching
the scene of action in this print, which may not happen to
be readily obtained from any other quarter.

In the year 1793 I was on board the Philadelphia ship
Carolina, which was several weeks at anchor in the very
spot which this print exhibits; and I have been at the bot-
tom in the place where this accident happened: it is com-
posed of a blue or greenish clay, indented with small holes
as if made with the fingers, which I am inclined to think
is the work of small fishes, wherewith the harbour abounds;
and the clay is covered with a thin film, or skin, not unlike
brown paper. The water (probably from the shade of the
savannas adjoining) has a greenish appearance, and is re-
plete with asmall species of worm, or maggot, similar to the
skippers in rotten cheese. I understood, however, that it is
not this but another species of worm which renders it ne=
cessary to copper the bottoms of the ships ; nor do the Spa-
niards ascribe to them any species of depredation, although
the surface of the harbour at some times exhibits them as
a kind of cream on the bason’s contents. This subject may
nevertheless merit the investigation of ship owners; and
it may also deserve consideration how far chemical know-
ledge may be directed to the discovery of some cheap sub-
stitute for copper, which may be niore generally applied te
ships in the merchant service, thereby economizing the con-
sumption of a material which constitutes the basis of a con-
siderable portion of British manufacture and commerce.

I beg leave to state, in regard to the case of the shark,
that it is by no means my intention to encourage further
éxperiments at the bottom of the harbour of the Havannah:
6n the contrary, J observed the Spaniards frequently bathing
near the shores, but neyer in the deep water, where the crew

of

318 On Vegetation.
of the-Carolina were accustomed to jump overboard. ¥F
merely state this fact, to distinguish a casual from an un=
avoidable case, and to: show that all dangers are not death,
no more than it should be conceived necessary that trayel-
Yers should be always killed in the Sicrra Movena, or im.
Cumberland Mountain in America, because such accidents
have been frequent antecedent to the period when civiliza~
fion conquered the wilderness. sim
Not being acquainted with the natural history of fishes,
E can only merely state another fact concerning sharks.
fn the harbour of ‘Charleston, in South Carolina, I was.
astonished to see a boy fall from a ship’s bowsprit into the
water, without injury, where two or three sharks were play-
ing about the sbip a few minutes before; but I was still
more so, at seeing two sharks playing about im the surf
where a:parcel of children were bathing im shallow water,
who seemed to be noways concerned for their safety. On
expressing my anxiety, and warning the children of their,
apparent danger, some of the inhabitants who stood on the
beach laughed, and assured me that those two sharks were
ald playmates of the children, who were well acquainted
with them ; for that they had long frequented the place,
and were not of a ravenous species; and that if one of the
dangerous kind came in the way I should soon see the chil-
dren scamper, as‘they were perfectly acquainted with the
difference between thée’two. If you deem these facts worth. °
publre notice, you aré at liberty to publish them, on the
authority of, Sir, your humble servant,
December 3, 1803. WiLiiim TaTHAM,

2s

LIX. On Vegetation; extracted from C. HAssENnFRAT2Z’§
Paper on that Sulject. By G.J. Wricur, Esq.

SIR, To Mr. Tilloch.

Tue fragment JI enclose for your insertion is extracted
from a memoir of Cit. Hassenfratz on vegetation *, a paper.
of some import, and frequently quoted by philosophical.
men, though not, that I have been able to find, inserted in
any nr publication. Imagining the subject of experi-
ment of So respectable a philosopher would not be regarded
as superfluous by your readers, [ have in my leisure hours
(and owing to the want of original matter, through the te
~~ Anrales de.Chinne, tome xii, and-xive ’
diousness

Dn Vegetation, sig

@iousness of experiments, and the pressure of other ayoca-
tions) endeavoured to put the principal topics of the paper
alluded to in as concise a method as may be; a species of
zelaxation which, if you approve of, I may be induced te
repeat. The frequent simular labours of the enlightened
character I quote form so respectable a precedent towards
the like intent, that I am prone to trust the present will
not be regarded by you as less valuable for its want of ori-
ginalitv on my part, inasmuch as the desire of diffusing
information forms the basis ef my metives for forwarding
it; an object not better to be obtained than will be accom=
plished by an insertion in your valuable publication, a work
not less to be cherished as a national acquisition than the
plan and perusal of it must be gratifying to the public, and
among others to your obliged servant,

Kenningtor, G. J. Wricur,
Jan. 14,'1804. id hal

_ The substances which bear the ‘greatest proportion, as
the constituent parts of plants (the ashes composing but 2
fractional part) are water, carbon, hydroden, and oxygen,
of which the proportions are found to vary in different ye-
gctables.

* Yan Helmont’s experiment on the growth of a willow,
which increased 60lb. in weight without diminution on the
part of the earth in which it vegetated, is well known, as is
also that of Duhamel, who observed the growth of an oak,
in water alone, for several years successively. . Add to these
the numerous experiments of M. Tillet, who sowed grains
ef corn in various mixtures of sand, pounded glass, earths,
&c. without being able to distinguish between the grains
so produced, and those sown in the usual way3 all which
experiments appear to set forth air and water as being the
matters essential to the nutrition of plants, and seem at the
same time to suppose the effect of manures to be contined
solely to the retention of the humidity necessary to vereta~
tion, the production of a slight degree of heat. for the
dasier developement of the young plant, and.the more per~
fect division of the suil for the readier extension of the
radical fibres. ~ Q:

Phat the increase of carbon in vegetables should be de-
rived from the mere media air and water, appears indeed
paradoxical; but Tillet’s experiments to ascertain the fact
are inconclusive, being conducted in perforated pots buried
in the ground. ‘The same processes, repeated by Hassen-,
gratz,. in insulated and unpertorated yessels (that is to. sayy.

“4 under

&°0 On Vegetation.

under such circumstances as totally precluded any contact
with vegetable earth) showed that plants vegetating in the
above-mentioned mixtures; perished after a while; and in
no instance survived a sufficient length of time to perfect the
parts of fructification. In fact, bulbs, cresses, and other plants;
which vegetate in water only, contain, after their growth,
rather less than the mean quantity of carbon that the origi
nal bulbs or seeds contained before their developement ; and.
whatever carbon is contained in the leaves and branches
of such plants, it has been furnished and carried up into them
by the water as a vehicle; yet allowing such plants only to
unfold their flowers, and no further.. This is analogous
to what we observe in the animal kingdom; as in eggs,
which contain within them a portion of nourishment ade=
quate to the life and growth of the embryo chick to a cer-
tain degree of perfection, beyond which it cannot exist or
increase without the administration of newly applied nutri-
ment. In like manner, every seed contains within itself a
certain portion of the carbonic principle, which, by the sole
aid of water, suffices to develop the young plant to a certaim
point, beyond which it cannot increase without the con-
currence of fresh carbon.
The attraction of the roots easily accounts for the in=
crease of water in plants; and the decomposition of a part
of the water deposited within them, alike explains the in*
erease of the hydrogen. The atigmentation of their carbon
has been endeavoured to be accounted for by some philo-
sophers as arising from the decomposition of the carbonic
acid in the air: an opinion founded on the fact that oxygen
is disengaged from plants in the act of vegetation ; and this
in greater proportion when watered with water impregnated
with carbonic acid gas. However this may be, the quan+
tity of residuary carbon is not increased by the process
mentioned ; for plants reared in aérated water, afford on
analysis no more carbon than if otherwise circumstanced.'
So also the supposition of the oxygen disengaged in vege=

tation being derived from carbonic acid decomposed by”

the plant is erroneous ; for air long confined, night and
day, over plants, undergoes no change either in volume or
in goodness. And this consequence ought naturally to
follow! from the experiments of Ingenhouz, which show
that whilst vegetables are under the infiuence of solar light,
they give out oxygen ; but, when deprived of that influence,
they take up the before disengaged oxygen, combine with
it a portion of their carbon, and give off the carbonic acid
resulting from their uaion: and with respect to the disen-

gagement

On Vegetation. 321

gagement of oxygen, during the presence of the light, and
the change of the same into carbonic acid in the dark, we
must allow there will be, between these gases, a certain
ratio depending on the longer or shorter duration of their
exposure to those extremes ; consequently there will be,
ceteris paribus, less oxygen and more carbonic acid given
out in winter than in summer,

Carbon is susceptible of solution or suspension in water,
as is evident from the coaly residue obtained on evaporating
the drainings of dunghills. Carbon is also in a soluble
State in all vegetable mould, as is shown by the brown
tinge of a cold infusion of any fertile soil. Wherever heaps
of dung are thrown, and water in the interim fallen, there
subsequent vegetation is more vigorous; and so it ever will
be where carbon is in a state of solubility by water. The
infusions of long and of spit, or perfectly rotted dung, are of
different hues, the former being but pale, as weakly charged
with carbon. On applying them as manure, the spot fed
with the latter produced the first year larger and more vi-
gorous plants than the former ; but in the second year
(neither parcel being fresh manured) the part supplied
with the long dung showed much the superiority ; and so
likewise in the third year this latter had somewhat the
advantage: proving that, in the long dung, less of the
carbon was (when first applied) in a state to be taken up
by water thanin the short and wholly putrified dung. The
latter, therefore, gives out its coaly principle the first year,
whereas the former requires more time for its carbon to be
rendered in the state proper to be taken up by the plant.
Nothing can better illustrate this than the effects of chips
of woodas a manure. These having lain some time heaped
up, so as to experience a beginning fermentation, were ~
laid upon a portion of land: during the first and second
years the earth so manured presented no better produce
than other in its vicinity not manured. In the third year
the production was more abundant. In the fourth yet
more. In the fifth it appeared to have attained its maxi-
mum of production, and diminished till the ninth, in which
the manure seemed wholly exhausted. In a word, all cir-
cumstances the same, vegetation is most strong and vigor-
ous where the soil contains the greatest quantity of carbon
in a state of solution. Yet, without doubt, there is a cer-
tain maximum with regard to the quantum required, beyond
which the presence of superabundant carbon will prove

unnecessary and expensive, but this proportion must in
Vout. XVII. No. 68. Xx every

322 On Vegetation.

every case be relative to the nature of each plant, as to its
exhausting power. *P

M. Baisse proved that plants growing in water tinged
with madder ee red; and Bonnet found them black
on growing in ink, These prove that the roots of plants
can take up coloured water, and deposit the colouring mat-
ter in the interior of the growing vegetable. On the same
principle they take up water holding carbon in solution , and,
depositing the same in the interior of the plants, contribute
to their increase.

If we compare then this manner of increase of carbon in
a plant, with the disengagement of oxygen ia the light,
carbonic acid in the dark, and the temperature of plants
during vegetation, we shall find that, during that process,
cold is produced when the plant is acted upon by the sun,
and warmth when under contrary circumstances. In the
former case, the decomposition and evaporation of the wa~
ter cause absorption of caloric, while one cause only tends
to its disengagement; namely, the combination of the
carbon, hydrogen, and other constituent parts of the plant,
whence it is probable cold is produced. While in the latter
case, and in the absence of the sun, the formation of car-
bonic acid, by the carbon in the plant, and the oxygen of
the atmosphere, must produce heat, owing to the different
capacities of those gases for caloric: in other words, the
quantity of combined caloric being greater in the oxygen
gas than is required by carbon for maintaining its aériform
acid state, the superabundant portion becomes free, and
sensible heat is produced. .

It follows, from the above recited experiments, that car-
bon, ina state of solution in water, is taken up by the
radical fibres of vegetables and deposited within the plant,
in the same manner as colouring particles are found to be,
thus Constituting the real pabulum of the vegetable king-
dom, without the presence of which in the soil no seed can
of itself veretate beyond that degree of perfection which its
own innate carbon may allow of, as the crisis stamped by
nature as that wherein it is ina condition to shift for itself,
provided the food proper to that intent is within its reach.
Exclusive of the mode of operation, and degrees of fertility
of different manures dependent on the greater or less state
of solubility of their contained carbon, another, not less
important act of vegetation, deduced from the above, is the
augmentation of the temperature of the atmosphere by
plants when not exposed to solar light, as also the dimiy

, nution

Use of alkalized Oxide of Iron in Calico Printing. 323

nution of the same whilst acted upon by that luminary; a
law in vegetable economy equally tending to, serve the
wisest of intentions, and forming but another link in that
chain of beautiful analogies which modern discoveries have
served to unfold as.eminently subservient to the welfare of
the human race, whether displayed in the reciprocal ser-
vices of the animal and vegetable kingdoms, the modifi-
cation of climate, by planetary as well as local advantages,
or the gift of those indigenous productions which consti-
tute an important requisite to internal prosperity and com-
mercial enterprise.

LX. Observations on the Use of Sraut’s alkalized Oxide of
fron * in Calico Printing. By J. M. Hausman fF.

JT mace great use of this dye in the preparation of printed
calicoes, and I endeavour, as much as possible, to over-
load it with oxide of iron. I tie up the metal destined for
solution into a bundle, that I may take it out at pleasure
when the nitrous acid is ready to flow over. By employing |
this precaution I guard against precipitation, and easily
suspend the solution; for when the bundle is taken out,
{after the effervescence, which produces’ a great heat, has
sufficiently subsided,) while an excess of acid still remains,
which is certainly necessary, you will obtain a pigment
without any deposit.

If a sufficient quantity of fluid, consisting of three parts
calcined carbonate of potash of the shops, and two parts of
water, be poured into the nitrous solution of iron, there
will, on stirring the mass, by which means it effervesces
a little in consequence of the excess of acid, be formed a
magia, to which as much liquid carbonate of potash must
be added as is necessary for its complete solution. This
dye, or this solution of iron, gives, with a fifth or a sixth
part of gum-water prepared from equal parts of gum-
arabic and water and then thickened, ochry yellow colours,
which can be easily purified. The addition of a twelfth
part of a decoction of yellow berries, with a twenty-fourth
part of a decoction of logwood, gives that tint known under
the name of American colour, and a twelfth part of a de-

* Stahl calls this union Tinctura mastis alkalina. It was afterwards
known by the name of Stahl’s aléalive anture of von: It is nothing
else than a combination of oxide of iion with potash, - See Mucquer’s
Chim. Worterbuch, vol. vi. Pp: 550. i

t From Allgemeines Journal der Chemie, No. 24.

X2 coction

394 Observations on the Use of Stahl’s

coction of logwood, without yellow berries, gives a chocos
Jate colour. g

If this dye be diluted with a sufficient quantity of water,
all the oxide falls to the bottom. When edulcorated, fil-
tered, and brought to a white heat in a crucible, this oxide
polishes steel as completely as the English colcothar.

Linen or worsted yarn imbibed with this dye, and then
immersed in a dye-liquor prepared with caustic alkali,
which precipitates the oxide of iron, acquires by this pro-
_ cess a much darker yellow than when it is left at rest for
twenty-four hours, and then dried and washed.

Every drop of a solution of caustic alkali applied to this
dye precipitates from it a part of the oxide as it overcomes
the carbonic acid. By these means it is completely de-
composed; and this oxide, when washed and exposed to
heat for a sufficient time, gives a very fine polish to steel.

This dye, as I have already said, 1s nothing else than a
solution of hyperoxygenated carbonate of iron by an alka-
line carbonate, which serves it as a vehicle ; only care must
be taken not to add too much when dark colours are re-
quired.

All solutions of iron sufficiently oxygenated, treated
with an alkaline carbonate in the same manner as the
nitrous solution of iron, are capable of producing a similar
dye. Ihave convinced myself of this fact by employing
the acetic, muriatic, and sulphuric acids for this purpose.
The latter I obtained in two ways: in ‘one I dissolved sul-
phate of iron in nitrous acid, and, when the effervescence
and disengagement of nitrous gas had ceased, subjected it
to evaporation : in the other, I proceeded according to the
process which I gave in my paper on the artificial prepara-
‘tion of volatile alkali, published in the Journal de Physique
for June 1787 ; that is, by suffering the solution of sulphate
of iron to absorb nitrous gas. By both solutions I obtained
a hyperoxygenated acetous solution of iron, as I decom-
posed it by acetate of lead.

A nitrous solution of copper, prepared from nine pounds
green oxide of copper, nine pounds of water, and three
pounds cream of tartar, with a solution of carbonate of
potash, and treated as the nitrous solution of iron, pro~
duces the same effects. When mixed with gum, and im-
printed on woollen or cotton stuffs, it deposits the oxide of
copper of a beautiful green tint. A gummed ammoniacal
solution of copper may be employed in its stead; for when
the cloth is dried the ammonia is disengaged from it, .

'* the

ree

alkalized Oxide of Iron in Calico Printing. 325

the green oxide remains united with it in consequence of
its cohesion,

If linen or woollen yarn be imbibed in nitrous acid
diluted with more or less water, or any other hyper-
oxygenated solution of iron, and then be exposed for some
minutes to a caustic alkaline ley, a beautiful nankeen co-
lour will be produced. Instead of this nitrous solution, a
solution more or less diluted of sulphuric acid may be em-
ployed. Many articles when taken from the caustic ley
are dirty, but when they have attracted the oxygen of the
atmosphere, they acquire the proper brightness. These
colours pass to violet and black by maddering. They will
acquire a deep black colour, as well as different shades of
gray, when treated with gall-nuts, sumach, or logwood.
Several blue shades may also be obtained from them, by
employing a ley of alkaline prussiate, or calcareous earth,
oxygenated by any acid. ‘The various shades of morose
gray are produced by stronger or weaker infusions of gall-
nuts, which must be suffered to dry on the yarn impreg-
nated with them; after which the yarn is immersed in sul-
phuric, nitric, muriatic, or acetic acid, diluted with water.

A nitrous ‘solution of iron, when freed from its acid by
evaporation, and when the residuum is brought to a white
heat in a crucible, gives an oxide of iron which is an excel-
lent polisher of steel. The case is the same with a solution
of iron in sulphuric acid; but in this case the oxide must
be longer exposed to heat. A muriatic solution of iron
may be employed for the same purpose; but the acid,
when evaporated by a strong heat, carries with it a large

ortion of the oxide. All methods in general, by which
iron can be sufficiently oxygenated, will produce an oxide
fit for the polishing of steel. \

I must here mention an experiment which I communi=
cated about ten years ago to my friends Wild and Arbogart.
Having once tried to oxygenate oxide of iron as much as
possible in order to convert it into acid, I mixed together,
in the course of several unsuccessful experiments, a pound
of a nitrous solution of iron and half a pound of concen
trated sulphuric acid. When the mixture was evaporated
to dryness in a porcelain dish, there remained a white re-
siduum, entirely insipid. On examining it several weeks
after, I found that it bad attracted moisture, and had
assumed an astringent taste. A few weeks after, when a
‘certain portion of it had dissolyed in the moisture which
this residuum had attracted from the atmosphere, I tans |

X 3 °

396 Use of alkalized Oxide of Iron in Calico Printing.

off the liquid, which still had an astringent taste, and pre+
served it ina glass. After some time I found in it very
beautiful colourless and transparent crystals, which resem-
bled alum. Having immersed it in an alkaline solution of
prussic acid, its surface-became covered with the most
beautiful Prussian blue, which suffered itself to be removed
by washing without its colour being changed. This blue
was reproduced as long as any of the crystals remained. In
the air these crystals became yellowish, in consequence, no
doubt, of the solar rays having disengaged from them 4
portion of oxygen; for when I examined them afterwards,
I found that they were nothing else than hyperoxygenated
sulphate of iron. This salt is insupportably astringent.
When diluted with a great deal of water a precipitate is
produced, and speedier when the mixture is exposed to
heat. The filtered precipitate had a most beautiful yellow |
colour. A high temperature, however, deprived it of its
rust colour, as it by these means lost its excess of oxygen.

On repeating this experiment I always obtained the same
result ; and when I exposed the white insipid residuum im
a glass retort, combined with a Woolf’s apparatus, to suclt
a degree of heat as brought it to a state of ignition, the acid
was disengaged from it in the form of sulphureous and
sulphuric acid, accompanied with a mixture of oxygen gas.
The oxide of iron obtained in the retort after the experi-
ment was of a brownish red colour, and fit for polishing.

Tf the quantity of the sulphuric acid be lessened, there
will be obtained, in like manner, a white pulverulent resi-
duum, which, notwithstanding its insipidity, dissolves in
an equal part of warm water, and after cooling, and being
left some time at rest, produces crystals.

The hyperoxygenated oxide of iron, obtained by caustic
alkali, from Stahl’s tincture of iron, or any other acid so-
lution of that metal, when precipitated and again dissolved
in sulphuric acid, with some excess of the fatter, gives
also beautiful erystals of hyperoxygenated sulphate of iron.

Fhe common sulphate of iron, which is oxygenated by
nitrous acid, or by the absorption of mitrous gas, does not
crystallize ; and, when the evaporation is not continued to
dryness, acquires the consistence of syrup or of honey.
But if a fifth or a sixth part of concentrated sulphuric acid
be added, a confused crystallization is immediately pro-
duced which forms a compact mass. This proves that
hyperoxygenated crystallized sulphate of iron requires a
greater quantity of acid than the common sulphate. a

ne

Improvement in the Form of Spectacle Glusses. 327

The muriatic acid becomes very strongly oxygenated:
when dissolved in hyperoxygenated sulphate of iron, which
thereby acquires a yellowish colour.

The hyperoxygenation of iron increases its affinity for
acids in such a manner that callico-printers make no use of
an acetic solution of hyperoxygenated oxide of iron, as it

does not readily give up its acid by drying.

LXI. On an Improvement in the Form of Spectacie Glasses.
By Wn. Hype Wottaston, M.D. F.R.S.*

I; must have been remarked by persons who make use of
spectacles, especially those who require glasses of short
focal distance, that objects seen through them appear di-
stinct only when viewed through the central parts of the
glasses ; that, when the direction of the sight E O, Fig. 1.
(Plate LX.) is considerably inclined to the surfaces, objects
appear distorted, and that this defect is greater in propor-
tion to the greater obliquity of that line.

It is on this account that opticians have lately made and
recommended spectacle glasses of Jess diameter than those
formerly in use, thinking that the extreme parts of the field
of vision, which from indistinctness were of little use, might
be spared without nmuch inconvenience. But this altera-
tion in the size of the glasses could hardly claim the merit
of an La FpROCEACH since for one defect it only substituted
another scarcely less objectionable.

It seems indeed rather extraordinary that during five
centuries which have elapsed since the invention of specta-
cles, neither theory nor accident should have produced any
considerable variation from their original construction.

It was indeed conceived by Huygens tT, that the glasses,
instead of being equally curved on both sides, as is cus-
tomary, should have the curvatures of their opposite sur-
faces in the proportion of 6 to 1, because he had. demon-
strated that such a form was best suited to the object-glasses
of telescopes.

Dr. Smith also, in his Treatise on Optics (p. 258.), re-
peats this opinion of Huygens in the Giochie cursory
manner; And consequently this figure of a class 3 is the

* Communicated by the author.
+ Diopu Prop. 28.

AA best

328 Improvement in the Form of Spectacle Glasses.

best for spectacles, as the double concave of like figure ts
the best to help short-sighted persons.”

But although it may be very true that such a form of
glass was best calculated for the object-glass of a telescope,
previous to the eelebrated discovery of the achromatic ob-
ject-glass by the late Mr. Dollond; yet, whatever advan-
tages might at any time be expected from the telescopic
object-glass so shaped, these were not to be obtained by 2
similar construction in spectacles, as may easily be seen by
considering the different uses of the respective instru-
ments.

In a telescope, in the first place, our view is necessarily

confined to a very small distance on each side of the axis 5
and secondly, every part of the object-glass contributes to
the distinctness of any object viewed.
It is under these circumstances alone that the proportion
of the curvatures above mentioned might be proper for a
single object-glass, as being capable of collecting into the
same focus the rays that fall on every part of it parallel to
the axis.

By spectacles, on the contrary, objects are to be viewed
if possible in every direction in which they might be seen
by the naked eye, which is often far removed from the
centres of the glasses; consequently, a construction that is
calculated to represent correctly central objects alone can-
not be the most advantageous.

In these also the portion of the glass employed at once is
scarcely larger than the pupil of the eye; so that any en-
deavour to procure the concurrence of all parts of a glass
in any one effect is evidently superfluous, and may also be
shown to be prejudicial.

It is therefore proposed to remedy the imperfections ob-
servable in the spectacle glasses hitherto generally used
upon a principle suggested by this latter consideration,
which presents an opportunity, by a different construction,
of rendering objects in all directions distinct.

The alteration requisite for this purpose is extremely sim-
ple, and easily intelligible. Supposing an eye to be placed
in the centre of any hollow globe of glass, it is plain that
objects would then be seen perpendicularly through its sur-
face in every direction. Consequently, the more nearly
any spectacle glass can be made to surround the eye, in the
manner of a globular surface, the more nearly will every
part of it be at r7ght angles to the line of sight, the more
uniform will be the power of its different parts, and the

2 : more

On the Strengths and Values of Spirituous Liquors. 329

more completely will the indistinctness of lateral objects
be avoided *.

According to this principle all spectacle glasses should be
convex on their exterior surface, and concave within. The
section of those for long-sighted persons will assume the
form of a meniscus or crescent, Fig. 2. and those adapted
for short sight will have their principal curvature on the
concave side, Fig. 8.

It is only necessary to add, that the advantage of this
improvement in the form of spectacle glasses has been
confirmed by a sufficient number of experiments on different
persons, and that those in particular, who are very long, or
yery short sighted, are much benefited by them.

The most advantageous proportions of curvature for ob-
taining the different focal lengths, now generally distin-

ished by certain numbers, have also been duly considered,
and the manufacture of spectacles on this construction has
been undertaken by Messrs. P. and J. Dollond, to whom
the exclusive sale of them is secured by patent, and whose
well-known skill in the construction of optical instru-
ments ensures to this improvement every advantage of
correct execution.

The opportunity afforded by these glasses of looking round
at various objects, it is thought may not improperly be ex-
pressed by the name of Periscopic Spectacles. .

eo

LXII. Of the general Relation between the Specific Gravi-
ties and the Strengths and Values of Spirituous Liquors,
and the Circumstances by which the former are influenced.

[Concluded from p. 210.]

Problems and Rules for the Adaptation of Mr. Gilpin’s
Tables to the present Standard,

§ 31. Prosrem I.—The specific gravity of a liquor at
any given temperature being given, to find that which it
possesses at any other temperature.

* To mathematicians it will be evident that any ray which does not
pass through the centre of a Jens cannot be at right angles to both sur-
faces; but they will also perceive, that when any small oblique pencil
makes equal angles with the two surfaces of a thin lens, the inclination
of it to each is so small, that its focal length B D, Fig 4. will not sen-
sibly differ from A C, that of a central pencil.

PRACTICAL

330 = Relation between the Specific Gravities and

Pracricat Rute.

Find the given specific gravity in the table, adapted to thé
given temperature, and take out the correspondent-numbers
from Column I. Search for these numbers in Column I of
the table for any other temperature, and the correspondent
specific gravity is that which is required.

EXAMPLES.

If a liquor have the specific gravity of 864 at 77°, what
will it have at 43°?

' Solution.

Looking for 864 in Column II of the table for 77°, we
find that the nearest numbers are 863°82 and 865:14 (or,
which amounts to the same thing, +86382 and .86514,
Mr. Gilpin considering the specific gravity of distilled water
as represented by unity instead of 1000 [see Note on § 5]) ;
whilst 100 Sp. + 27 W., and 100 Sp. + 28 W., are also
the correspondent numbers in Column I. Taking propor-
tional parts, therefore, 864 in Column II answers to a liquor
which, according to Column I, contains 100 parts of Mr.
Gilpin’s aleohol combined with 27°14 by weight of water;
and again, looking for this same compound in Column I of
the table for 43°, we find in like manner that the corre-
spondent specific gravity-at that temperature, as expressed

in, Column II of that table, is 879°85.

§ 32. Propiem IT.—To find the per-centage of any li-

quor whose specific gravity and temperature are given.
PracTicaL RuLEs.
Look into Column IT of the table answering to the given

temperature for the given specific gravity, and take out the .

correspondent number from Column VIII. Multiply 162°42
by this number, and the product is the answer.

Or, add 2°2106308 to the logarithm of the number so
found in Column VII, and the sum will be.the logarithm
of the per-centage.

EXaMPLeEs.

Y. What is the per-centage of a liquor whose specific
gravity at 48° is 887?

Solution.

We must here, firstly, look into Column II of the table
marked *“* HEAT 48°” for 887. The nearest numbers are
8865°00 and 887-16. The correspondent numbers in Co-
lumn VIII are against the former -8014, and — the

atter

:
|

the Strengths and Values of Spirituous Liquors. 33¥

latter 7965. Taking proportional parts, as before, +7972
in Column VIII answers to 887 in Column II.
_ Therefore, by the first method, 162-42 x *7972, oF
129°48, is the per-centage required.
And, by the second method, to log. +7972
Add the constant log.

1°9015673
22106308

-——_——

to the sum, is the per-centage required

And 129°48, the natural number answering
2°1191981
= 29°48 O.P.

eee oe

2. What is the per-centagze of a liquor whose specific
gravity at 75° is 9531?

Solution.

On looking into the Columns II and VIII of the table
marked “ HEAT 75°’, we find that the number in the latter
corresponding to 9534 in the former is -3827.

Therefore, by the first. method, 162°42 x *3827, or
6216, is the required per-centage.

And by the latter, log. +3827 =
Constant log. =

And the same number 62°16 answering to
the sum, indicates the per-centage as be- }1°7934893
fore (= 37°84 U.P.) J

eee

§ 33. Propiem III.—The per-centage of a liquor at a
given temperature being given, to find its specific gravity
at that temperature.

Pracricay Rutes.

Multiply the per-centage ly +006157 ; search for the
product in Column VIII of the table adapted to the given
temperature, and the correspondent number in Column II is
its specific gravity.

Or, add the constant logarithm 3°7 893692 to that of the
per-centage; search for the correspondent natural number
in Column VIII of the proper table, and the specific gravity
against it is that of the liquor.

EXAMPLES.

_ 1. What is the specific gravity of a liquor at 48°, which
18 129°48 (or 29°48 O.P.) at that temperature ?

Solution.

332 Relation between the Specific Gravities and

Solution.

Here, 129°48 x *006157 is = *7972.

Or, 3°7893692 + 2°1122027 (= log. of 129°48) =
1°9015719 = log. of *7972.

Which number being found in Column VIII of the table
marked “ HEAT 48°,” gives 887 for the correspondent spe-
cific gravity in Column IL, and which is accordingly that
of the liquor,

2. What is the specific gravity of a liquor at 75°, which
is 62°16 (or 37°84 U.P.) at that temperature ?

Solution.

In this case 62°16 x °006157 (or the natural number
answering to the logarithm 1*5828802, being the sum of
°1°7935110, the log. of 62°16 and 3°7893692) is *3827,
which being found in Column VIII of the table marked
“ HEAT 75°,” gives 9531 in Column II for the specific
gravity of the liquor at that temperature.

§ 34. Proptem IV.—The per-centage of a liquor at a
given temperature being given, to find that olla it pose
sesses at any oiher temperature.

Practica RULE.

Multiply the given per-ceniage of the liquor by +00°6157
(either by means of natural numbers or by the addition of
3°7893692 to its logarithm), as in Protlem LI. Find the
— product in Column VIII of the table corresponding to its
temperature, and iake out the correspondent numbers from
Column I. Enter the table adapted to the temperature at
which its per-centage is required with these numbers ; take
out the correspondent number from Column VIII and mul-
tiply it by 162°42, as in Problem Li, The product is the
per-centage at that temperature.

é EXAMPLE.

What is the per-centage of brandy at 75°, which is 105

(or 5 O.P.) at 33°?
Solution.
105 X *006157 = *6465.

And *6465, in Column VIII of the table for 33°, answers
to a compound of 100 + 73°8 in Column I.

This same compound being found in Column I of the
table for 75°, gives *6337 in Column VIII; and this mul-
tiplied by 162°42 is = 102°93, the required per-centage at
that temperature, if

ihe Strengths and Values of Spirituous Liquors. 333

Tf the gallon of proof spirit at 60°, therefore, be taken as
the standard, this liquor loses more than two per cent. in
its real value per gallon by the elevation of its temperature
trom 33° io 75°.

§ 35. Proptem V.—The per-centage and temperature of
a liquor being given, to find the concentration per cent., or
that diminution in measure which would take place on re=
ducing 100 parts of it to proof, or proof to 100 parts of

such liquor at the same temperature.

PRACTICAL RULE.

Firstly, Look into Column I of the table adapted to ihe
guren temperature for the liquor answering to +6157 in Co-
umn VILL (this being proof in all the tables) ; divide the
correspondent number in Column VI by that in Column V;
multiply the quotient (which at the temperature of 60° is
*027768) ly the given per-centage, and the product will
be the concentration of the equivalent quantity of proof, or
that contained in 100 parts of the given liquor, if it were
made up from M. Gilpin’s alcohol, aceording to the suppo-
sition on which his tables are founded.

Secondly, Look for the given liquor in the same talle
(having first found its correspondent number in Column V LIE
by Problem IIL), and divide the number in Column VI
(taking all the three figures as integers) by that m Co-
lumn V, and the difference between the former product and
this quotient will le the concentration required.

EXAMPLE.

What is the concentration per cent. on reducing rum of
145 (or 45 O.P.) to proof at 77°?

Solution.

Firstly, Against +6157 in Column VIII (which, as be-
fore mentioned, indicates proof), in the table for 77°, the
correspondent numbers in Column VI and V are 4.21 and
160-37 ; the quotient of the former by the latter is -02625
and 02625 x 1451s = 3°8065.

Secondly, Against +8928 in Column VIII of the same table,

the correspondent numbers in Column VI and V are 1°26
: 196.
and 110°9 respectively, and 755 1s = 114.

And 3:8065 — 1°14 is = 2°667, or 22.

The concentration, therefore, under these circumstances,
would be 2% per cent. on the quantity of the over-proof re-
duced, and it would therefore require 474 per cent, of water
to reduce it.

§ 36.

334 Relation between the Specific Gravities and

§ 36. Prostem VI.—The quantities ly measure of any
number af liquors of different strengths, and their per-cent-
age, at a given temperature being given, to find the per-
centage of the compound when reduced to that temperature.

Practica, RULE.

Firstly, Find the tabular specific gravity of each liquor
at the gwen temperature ly Problem LI, and multiply suck
quantity by its respective specific gravity so found.

Secondly, Find the compound correspondent to each in
Column I; multiply each product obtained as above by the
weight of the spirit in its respective compound as found in
that column, and divide the product by the sum of the weights
of its spirit and water.

Thirdly, Find a liquor in Column I whose weight of spirit
as to that of its whale composition as the sum of all the quo-
tients obtained in the second step to that of all the products
obtained in the first ; and it will be that which is equivalent
to the compound produced by the mixture of all the given
liquors, whose per-centage may therefore be determined by
Problem II, .

EXAMPLE.

Suppose we mix 556 gallons of brandy of 111 (ar
11 O.P.), 942 of 93 (or 7 U.P.), 427 of 80 (or 20 U.P.),
346 of 117 (or 17 O.P.), and 1111 of 105 (or 5 O.P.), all
at 67°, together; what will be the per-centage of the com~
pound ?

Solution,
Firstly,
The tabular specific gravity of 111 at 67° (by

Prob. III) is = 909-44, which x 556is - = 501!°76
That of 93 is = 995-04, which x 942is - = 871°39
_ Phat of 80 is = 939-48, which x 427is - = 401°16
That of 117 is = 894°33, which x 346is - = 309°44
That of 105 is = 910°25, which x 1111 is - = 1011°30

And the sum of these products is - = 3095-05

Secondly,

111 at 67° is = 100 Sp. + 60-05 W. and. 501-76 x 100 + 160:05 = 318-50
93 - - - is = 100Sp.4 95.383 W.and 871-39 x 100 + 195°83 = 44497
80 -- - is = 100 W. + 76.24 Sp.and 40116 x 76-24 +176-24 = 173:54

117 - - - is = 100Sp.+ 50-49 W. and 30944 % 100 + 150-49 = 205-62

105 - - - is = 100 Sp.-+ 70-66 W. and 1011/90 x 100 + 17066 = 59258

And the sum of these quotients is = 1730-21

Thirdly, 1730°91 : 3095°05 :: 100: 178°888.
The

the Strengths and Values of Spirituous Liquors. 335

The resulting compound will therefore be found to be
equal in strength to one composed of 100 parts by weight

.of Mr. Gilpin’s alcohol with 78°88 of water, and which is,

by Problem II, = 100°765 (= about 4 or 3 quarts O.P.)
at 67°.

§ 37. Proptem VII.—To jind the quantity by measure
which will be produced by a mixture of given quantities of
different strengths at any given temperature, as in the last
problem. ;

Practica RuLE.

Divide the sum of the products found in the first step of
the preceding process by the talutar specific gravity of the
resulting compound, and the quotient will be the quantity

by measure produced.

EXAMPLE.
What quantity of the compound shall we have under the
circumstances stated in the example to the last problem ?

Solution.
The tabular specific gravity of the resulting compound of

-100°765 (or & Q.P:) at 67° is "91558 ; and 3095°95

+ "91555
3380°43 gallons at that temperature. _ !

Note. The sum of the quantities mixed in the present
instance was 3382 gallons; so that the concentration by

mixture in this case was about six quarts.

§ 38. Prostem VIII.—To jind what proportions, ly

weight or measure, of any number of liquors of different
Strength, but at the same temperature, must be mixed toge-

ther in order to produce a compound which shall le of any
required strength between that of the strongest and the
weakest of them at that temperature.

PRACTICAL RULE.

Firsily, Find the specific gravity of each liquor, and also
that of the required compound at the given temperature, by
Problem Il.

Secondly, Find the compound corresponding to each of the
ni liquors, and also to the required compound, in Co-

umn I, and divide the weight of the spirit in each compound
by the sum of the weights of its spirit and water.

Thirdly, Range the quotients belonging to these given
Liquors in any convenient order, and couple or pair them to-
gether by curves or circumfleaes, so that every one which is

greater

336 Relation between the Specific Gravities

eater than that belonging to the required composition may
e coupled or paired with some one which is less. >

Fourthly, Against each of these place the difference be-
tween that with which it is so coupled or paired, and the

uotient belonging to the required compound.

Fifthly, Then as the sum of all these differences is to the
difference (or sum of the differences, if more than one,)
standing against each quotient, so is the spectfic gravity of
the required compound to the proportion of each by weight
which will produce it ; which proportion, divided by the re-
spective specific gravity of each before mixture, gives that
of each by measure. ¥

EXAMPLE.

In order to make up 774 gallons of a compound which
shall be 108 (or 8 O.P.), at 50°, how much must I take of
each of five liquors, of which one is 127 (or 27 O.P.), an-
other 116 (or 16 O.P.), another 102 (or 20.P.), another
87 (or 13 U.P.), and another 67 (or 33 U.P.)?

Solution.

Firstly, The specific gravity of 127 at 50° is = *88948;
that of 116 = -90473; that of 102 = -92239; that of 87
== °93954; that of 67 = '95827 ; and that of the required
compound of 108 = *91498, by Problem III,

Secondly, The com- em;
pound answering to }—=100 Sp.-+ 37-89 W. "T2522 by semecal
127 at 50° is ah, TET
That answering to 116 is = 100 Sp. 53:55 w. ( 284 J .g5ro5 | Pimms _

g P con- hol, of the
102 is = 100 Sp.-++ 78-03 W. eat ‘56170 Gs omhe Pee,
-—— 87is = 100 W..8883 Sp. | ‘7 | -a7o4o | PEO ES
—— 67 is = 100 W.-+- 5507 Sp. S510 teal
And the required spirit is = 100 Sp.-+ 66°77 W. “60101 3

Thirdly and fourthly,
The proportion by weight

we

es

= "60101

of spirit in the required eee
eompound 1s Differences,
“72592 =°24588

03931 _,
ipsa -y3051 5, =" 16998
‘56170 *05024
47042 © *05024
"35513 *19421

Sum of the differences = *64047

Fifthly,

the Sirengths and Values of Spirituous Liquors. 337

Fifthly,

"24588 ‘35197 = the proportion by
weight ot 127
-16990 -94972 = that of 116
“64047 : 3 fe :
ht °05094 oa9° ‘07177 = that of each of
those of 102 and 87

+1249] 17745 = that of 67.

And 3322 = -39491, the proportion by measure of
SS 127 (or 97 O.P.)

“24272 = ‘26898, that of 116 (or 16 O.P.)
“90473

ee = ‘07781, that of 102 (or 2 O.P.)

7177 — .97639, that of 87 (or 13 U.P.)
°93954

A745 = +18517, that of 67 (or 33 U.P.)

"95027
But these making 1:00256, the concéntration by mixture
is therefore -00256 of the whole; and, multiplying each of
these by the required quantity, 774 gallons, we get >
305°66 gallons for the requisite quantity by measure of 127
(or 27 O.P.)

207°65 gallons for that of 116 (or 16 O.P.)

60°23 gallons for that of 102 (or 2 O.P.)

59°13 gallons for that of 87 (or 13 U.P.)

143°33 gallons for that of 67 (or 33 U.P.)
776. gallons in the whole, composing after the mixture
the 774 gallons required; the concentration in this case
being exactly 2‘gallons.

It will easily be perceived, that, when the proportions of
more than two of these different kinds of spirit are undefined,
as in the preceding question, the problem admits of many
answers, and the quantities of each kind of liquor may ac-
cordingly be variously proportioned.

A variety of other problems may be proposed and solved
by means of these tables, which the mathematician will
suggest to himself without any difficulty. There is, in fact,
no possible question respecting these matters, of which,
with the proper application of arithmetic or algebra, we
may not here find the solution. The authors of this essay

Vox. XVII. No. 68. yg conceive

338 Relation between the Specific Gravities and

conceive themselves to be as patient and attentive in experi-,
ment as the majority of persons; but they are obliged to’
‘confess, that they so far prefer these experiments to their
own, that they have long taken them as the groundwork of
all their calculations for the graduation of their spirit-hydro-
meters.

§ 39. As every one into whose hands the present essay
may fall may, perhaps, not be in possession of the tables
of Mr. Gilpin, we shall in this chapter present the reader
with two short but correet tables of our own, calculated
from his experiments by the methods before given in the
last; by the help of which the per-centage, according to
the mode of estimating it, described and recommended in
§ 26, and the concentration per cent. on reducing any
over-proof spirit to proof, or proof to an under-proof, may
be accurately obtained, and that even with more facility
than from those of Mr. Gilpin himself, in their present
state of arrangement,

TABLE I.

_ For finding the Specific Gravity of any Spirituous Com-
pound at 60°, when that which it possesses at any other
Temperature is given.

. Correct. is Correct. |, . Correct, |
Specific | for each Specific | for each | Specific for each
Gravity. | Degree. Gravity. | Degree. Gravity. | Degree. |

810 to 820, -475/880 to 890 + -456|950 to g60\+ +340)
20to 30+ +473) 90 to 900+ 7450) GOto 70\+ -269,
30 to 40\+ -472'900 to 910+ °442) 7Oto 80) -165,
40 to 50\+ +471! 10to 2964 °434) soto 90+ -090|
50 to 604-471 20to 30+ +424] 90 to 1000|+ 084
60 to 70\-466| 30to 40+ -406
70 to Ss0'+ +460} 40 to 504-381

USE OF THE TABLE,

The above Table is to be entered with the existing specific
gravity of the liquor, against which will be found the cor-
rection to be added to it for every degree which its tempera-
ture is higher, or subtracted for every degree which it is
lower than 60°.

EXAMPLE.

If a quantity of rum is of the specific gravity of 894 at

73°, what will be its specific gravity at 60°?

Ans,

the Strengths and Values of Spiriluous Liquors. 3

tad

ao

9

Ans. Here; the specific gravity being between 890 and

§00, we must ddd ‘450 for each degree of difference. The
Specific gravity, therefore, at 60° would, of course, be 894
+ °450 X 13 = 899°S5.

Taste II:

Fur finding the Percentage of any Spirituovs Compound

given.

epssies [Perscentase. Corr?" |(Cration:| cach 1 [csi rvssene rer iceean., | cock,
ae aes | peers | aor, Th 3 Pees

$10 169°22 15°62 | 905\111-79 56
496 || 080 || ‘772 037.

15|167°09|. .; |/5:22 | 10,107'93 37
}-460 074 | "| 778 037:
20 164°79 4°85 | 15/104'04 POG) oo
| AT4 068 808 037

25 162-42 131) 20|100:00 * OO
-506 “063 834 033

30 159°89 4:19 25} 95'83| om

"524 052 854 ‘030

35)157°27 3°93 30! 91°56 ' 33
| “542 ‘057 “889 028
40 154°56 3°64 | 35] 87°22 APRN
562 055 -958 024

45,151°75 3:37 40| 82°43 O: 59
584 054 || ‘988 021

50 148°83 3°10 | 45] 77:49 0° G9
bers | 600 054 || 1-050 | 017

| 55 145°83 2°63 |, 50} 72:24 0° 7
616 047 1-124 011

60) 142°75 2°59 55| 66°62 0: 83
| “634 051 1-252 ‘001

| 65}139°58 234 60| 60°36 O° 82
646 || 1048 {1-412 013

| 701136-35 2°10 65| 53°30] o 76
| ‘656 | ‘048 1590 027

ho 186 70) 45°35 0: 62
“670 | “048 1-712 038

| 80)129°72 11°62 75| 36-79 O° 44
! 682 || 043 1-732 037

| $5)126°31 \L-41 80} 28°13 O° 25
) “700 : 044 i 1-620 030

g0!122°81 11g | 95 20°03 0° 10
: Ss) | ne 045 ||| 1-482 018

| g5|119°25 | 0°06 | go} 12°62 O° Ol
4 | *734 || 040 | | 1-322 002

, GOO 11558 (0-76 95, GOl 0'002
758 || 041 || | 1-202 001
| sHirzg} io-56 1000) 0°00) yh eee

¥¢2 UsE

at 60°; when its Specific Gravity dt that Tentperature is

340° On the Strengths and Values of Spirituows Liquors.

USE OF THE PRECEDING TABLE.:

This Table is to be entered with the specific gravity next
below that of the spirit at 60°, against which there will be

found, in the second column, the per-centage if that were.

really the specific gravity, and in tlie third the per-centage to
be subtracted for every unit that its specific gravity exceeds
the number in the first column. The fourth column, in
like marmer, contains the concentration per cent. of the
liquor against whose specific gravity it stands; and the
fifth, the correction to. be applied to the concentration for
every unit which the specific pravity differs from the nearest
in the first column.
EXAMPLE.

What quantity of water must we add to £97 gallons of a.
liquor whose specific gravity is‘ 883 at 48°, to reduce it to
proof; and how much proof spirit will it make ?

Ans. We find by Table I that the specific gravity of the
liquoe at 60° would be 883 — *456 * 19 = 877} very
nearly.

We see also by Table II that if the specific eravity at 60°
was 875, the per-centage would be 133-07; but that, as it
is $874, we must subtract *670 x 24, or 1:67, from the
per-centage standing against 875. The real per-centage
of the liquor, therefore, at 60° is 133°07,— 1°67 = 131°4;
and 100: 131°4 :: 427 : 561°08; which latter, therefore,
will be the quantity of proof spirit produced.

The only remaining question is as to the quantity of
water necessary to produce these 561 gallons of proof. For
this we must find the concentration by Table Il. Now
the concentration of spuit of 875 at 60° is 1°86 per cent.,
and that of spirit of 8771 = 1:86 — :048 x 94 = 1°74.
Therefore 31:4 + 1°74, or 33°14 gallons, is the quantity
of water to: be added to every rod gallons of the given spirit
to reduce'it to: proof, making 141+ gallons in the whole.

§ 40. The two preceding Tables, therefore, as will be seen
by the foregoing example, are, in fact, capable of answer-
mig all the most necessary questions to: be resolved by those
of Mr. Gilpin, and the solution of which cannot, indeed,
be obtained trom them except by a process of some Tength.
The calculation of the numbers in these tables, short as
they are, was a work which occasioned’ the authors some
trouble, but which was necessary for the graduation of
those instruments with which they have, in a great mea-
sure, supplied Europe. They give the per-centage and -con-
centration at 60° only, on the suppositien that the given

liquor

On the Flan of New Zealand. 341

liquor is reduced to and measured at that heat; and the
‘computation from-them, though most strictly accurate in
that case, will therefore be liable to some smail error in the
extremes of temperature; they will, however, be found to
be sufficiently correct for all practical purposes. ‘Should
the legislature change the standard of proof, they will of
course become in a great measure useless as well as the in-
struments which are graduated from them, and new ones
must therefore be calculated.

LXIIL. Extract of a Memoir read in the French National
Institute, on the Strength of the Flax of New Zealand,
compared with that of the Filaments of the Aloe, of Hemp,
Flax, and Silk. By C. LABILLARDIERE.

dove flax of New Zealand, which, as is well known, 1s
obtained from a plant of the family of the asphodela, called
Phormium tenax, holds the first rank among the vegetable
fibres, yet known, proper for the making of ropes. This
fact was first made known by the celebratea Captain Cook
and his illustrious fellow-navigator Sir Joseph Banks. It
was afterwards confirmed by Dr. Forster, who gave a good
description of the plant, which he found growing in full
vigour during various excursions in New Zealand, at seve-
ral parts of which he touched when he accompanied Cap-
tain Cook on his second voyage round the world. <A good
ficure of the plant may be scen in the first volume of the
account of that voyage, and also in Miller’s Icones Plan-
tarum. Dr. Forster has decribed all the parts of fructifica-
tion, and illustrated them with figures, in his work on the
new genera of plants discovered in the South Seas.

No person, however, bas ever yet attempted to ascertain
how far the fibres of the Phormium tenax are superior in
strength tothose of hemp. Thisis the object of the present
memoir, in which I shal] compare their strength with that of
the filaments of the aloe, of flax, and of silk. It is of the
more importance to examine the strength of the flax of New
Zealand, as compared with that of hemp in particular, be-
cause it might be substituted tor the latter with great ad-
vantage in the navy, whereas tke other substances are too
scarce and too dear, or much inferior in utility.

The flax of New Zealand, which I submitted to exami-
mation in order to ascertain its strength, was given to me
in exchange for toys by some of the inhabitants of that exten-
sive country, with whom we had an intercourse, towards its

Y 3 northern

342 On the Flax of New Zealund.

northern point, during the voyaye undertaken in search of
Perouse ; Ventose oad, Ist year of the republic. The plant
which produces itis of great use to these savages ; and when
they approached us, the first articles they exhibited were
large handfuls of its leaves prepared for various purposes,

Even when at a considerable distance from us they waved ~

them with a sort of enthusiasm, as if desirous to make
known to us their yalue, and we soon found that we had
properly understood this kind of language, for they set a
very high price on them when they got on board our vessel.

For my experiments I preferred these filaments to those
produced from the leaves of the same plant raised i in green=
houses, where the fibres certainly do not acquire so “much
strength as in the open air; besides, the season proper for
collecting leaves capable of giving the strongest fibres can
be known only by experience.

The apparatus I employed for ascertaining the strength
of the different fibres which I subjected to trial consisted
of two pieces af wood, ten inches in. height, fixed ona
plank in a vertical direction, at the distance of 6 centime-
ters, or 27598 inches from each other; they were slightly

rounded at the upper extremity, and on the exterior part of

each was fixed a small iron cy linder, about a millimetre in
diameter. ‘To these two small cylinders I affixed the fila-
ments the strength af which I intended to try. They rested
on each side on 1 the rounded extremities of the pieces of
wood already mentioned. I took the \precaubon to employ
fibres of the same diameter, that is J, of a millimetre oy
0:0443 of a line, which I verified by means of a microscope
and a good micrometer, taking care to twist equally the
part of the filament which I examined, having chosen it
as far as possible of the same dimensions throughout its
whole length. I tried the strength of it from every 8 centi-
metres to “g centimetres, or every, 2 inches 11: 464 lines,
which was the distance between the pieces af wood, and I
suspended from about the middle of it, by means of a wire
hook well covered with hemp, a weight w hich I uarersed
until the filament was broken.

I took care that it should not be twisted, in order that I
might ascertain its whole streneth, for without this precau-
tion it would have broken, as 1s well know n, much sooner.
Besides, for many reasons which it would be superfluous to
mention here, I should have obtained results much less cer-
tain 5 and it is needless to observe that, in such cases, a
rigorous determination cannot be obtained, but merely an
appr oximation,

After

On the Flax of New Zealand. 343

After having tried the strength of twelve lengths of
hemp, as above described, and having divided the sum by
that number, to ascertain the mean strength of each, I
found that it was equal to 164, while that of the fibres of the
Phormium tenax, tried in the same state, was 23-6.. The
filaments of the aloe gave only 7, flax 113, and silk 34; or,
in other words, the fibres of hemp broke only with a weight
of 400°5917 grammes, that of the flax of New Zealand by
590°5034 grammes, flax by 295°8228 grammes, and silk
by 855°9978 grammes.

The hemp and flax which I employed for these experi-
ments were the first fibres of the best kind produced in the
department of L’Ome. I extracted, by maceration and
slight friction to detach the parenchyme, the fibres of the
aloe from a leaf of the Agave feetida, Linn. or the Fur-
crea gigantea, VENT. which was given to me by my col-
league C, Thouin.

I must here observe, that at first I took the filaments of a
diameter much smaller, 35th of a millimetre, or 0:0221 of a
line, and even less ; but I soon observed that it was difficult
to obtain them, of that tenuity without a great many in~-
equalities and other defects, which prevented the exactness
of the results; besides, the more delicate they were, the
more difficult it was to ascertain their diameter. I paid
attention, therefore, to those only the diameter of which
was +, of a millimetre.

It may, therefore, be readily conceived what advantage
it would be to the navy to have ropes, the strength of
which, were it confined merely to this proportion, woul
be almost one-half greater than that of hemp ropes. But
I have no hesitation to assert that it will far exceed it ; for
the fibres of the flax of New Zealand, according to a series
of comparative experiments which I made on purpose to
determine the tension of which they are susceptible before
they break, are more tensible by one-half than those of
hemp ; and the principal cause of the diminution of the
strength of a rope, in proportion to its being more twisted,
arises in particillne from the fibres of which it is composed
experiencing different degrees of tension, the strength
and inequality of which are increased by torsion. But it
is evident that the more the fibres which enter into a rope
are susceptible of tension, the less is the difference in the
distribution of their strength, whence it results that. the
most tensible fibres, ceteris parilus, will always make the
best ropes.

It has been observed that certain kinds of hemp, hin

» stiff,

344 On the Flax of New Zealand.

stiff, but very strong fibres, are often capable of less resist-
ance, when employed to make ropes, than other kinds, the
fibres of which are weaker, but softer and more flexible. It
is besides known, that stiff fibres break by a weak degree
of torsion, which is resisted by those that have more
flexibility.

To ascertain the tensibility of the fibres of the flax of
New Zealand, I took six of 3!, millimetre, or 0°0443 line
in diameter, and suspended to lengths of 14 centimetres, or
5 inches 2-062 lines, a weight which I gradually increased,
examining by what quantity they were extended before they
broke. The sum of these quantities, divided by the num-
ber of the filaments subjecied to trial, gave for quotient the
mean term of the tensibility of each. Having subjected
to the same trial the filaments of the aloe, of hemp, of
flax, and of silk, the results which I obtained were: for
the flax 1°1279 millimetres; for the hemp 2°2558; for the
flax of New Zealand 3:3837; for the aloe 5°6395; and for
the silk 11°2790: so that the tensibility of flax being equal
to half that of hemp will be expressed by 1; that of the
Phormium tenax by 14; that of the filaments of the aloe by
24; and that of silk by 5. It is thence seen what prodigious

ower af resistance is exhibited by a few threads of silk,
carefully spun, as their very great tensibility causes them
all to make an effort nearly equal before they yield to the
effort made to break them. ,

It may not be improper here to remark, that the Chinese,
who make great use of silk strings for their musical instru~
ments, have no doubt found that twisting them for that
purpose hurts their strength, and also the justness of the
sound, for they are manufactured without twisting; the
threads of which they are composed being merely united by
means of an elastic resin: on this account they are, on the
first view, taken for catgut. I have no doubt that if our
artists would attempt this new manufacture, their labours
would be attended with success, especially as they employ
with great dexterity various kinds of elastic resin; but that
extracted from the Vahe of Madagascar (Vahea elastica),
would be preferable to caoutchouc, which comes from
Guyana, because the latter has a very dark tint, while the
ether inclines very much to a white colour. It readily dis-
selves, as is well known, in ether. Besides gum elastic
extracted from several other vegetables might also be em-
ployed for the same purpose. .

The Phorminm tenax is far from being the only plant of .
the division of the monocotyledons, capable of furmishing ~

filaments

On the Flax of New Zealand. 345

filaments proper for the uses of rope-making; for besides
some gramineous plants, most of the palms, and all the
species of the Agave, &c. there are many others of this
great division which have not yet been employed, and
which might be turned to advantage, particularly several
kinds of iris, the leaves of which possess very~ great
strength.

I must here observe, that in most plants of the division
of the monocotyledons, the leaves produce the filaments
proper for the purposes of rope-making; and the disposi-
tion of their fibres, which is nearly parallel throughout the
whole length of the leaves, will call to the remembrance
of botanists the excellent memoir of our colleague Desfon-
taines, on the organization of the monocotyledon plants.
On the other hand, in the diyision of the dicotyledons, the
filaments employed for ropes is obtained from the bark ;
and itis well known, that among the great number of sec-
tions which these vegetables contain, they are found chiefly
in those of the Thymeli, Urtice, Malvaceae, Tilia, and
the Amentacee. The bark of a shrub of the first section
(of a new kind of Pimelea) produces filaments which I have
seen the inhabitants of Cape Van Diemen employ for the
purpose of making ropes. These savages have so little in-
dustry, that they use them without the least preparation.
They even take no advantage of a very excellent kind of
flax which grows spontaneously on their coasts. The crude
bark of the Pimelea abovementioned formed the handles of
some baskets made of reeds, which the women at the hours
of repast filled with shell-fish, diving in the sea to consi-
derable depths, at the risk of being devoured by sharks, or
of being detained at the bottom of the water by marine
plants, some of which, and particularly the Ficus pyriferus,
are several hundreds of feet in length.

They employed this bark also for fastening round their
bodies the skin of the kangaroo, the only clothing worn by
the best dressed of these savages ; for several of them were
entirely naked, though exposed to severe cold in the Jati-
tude of 44° South, and by a very strange kind of whim this
vestment served only to cover the shoulders.

The Phormium tenax will succeed perfectly in France, for
it is found in New Zealand from lat. 34° to lat. 47° South,
and is exposed there to very severe frosts in the most
southern part of that very large country. Moist places are
better suited to it than dry, and the same may be said of
most of the other Lilacei. It would thrive well in many of
the marshy districts, which at present are considered as use-

less

346 On the Flax of New Zealand.

Fess; Besides, it is a lively plant, and will require very
hittle cate. It may readily be conceived what advantages
faust result from the culture of this valuable plant, and
particularly to the navy, as it will lighten im a very consi~
derable degree the lading of our vessels, tor the weight of
the rigging im a 74gun ship is estinrated at 3734-605
mvriagrammes, or 68000 pounds. The use of the flax of
New Holland would lessen this weight more than one-half;
and also that of the other ropes, which are above the line
ef flotation; and therefore the vessel would be capable of
taking in 2 much greater quantity of provisions. Besides,
# is well known that the less the diameter of the repes
above the l}ne of flotation, the Jess wilk be the lee-way ;
and, therefore, these mew ropes will contribute to accelerate
the progress of ships of war, which will still be increased
by the lightening they will experience when loaded with a
less weight than usual. These ropes being smaller and
kighter than those made with hemp, fewer hands will be
teqnired to manage them ; so that, if introduced, shrps will
need fewer men than those rigged with hemp.

kt is evident also that fibres so strong and so pliable will
be proper for the fabrication of different kinds of cloth, and
may be substituted with advantage in our manefactories for
hemp and even flax. They will no doubt retain in the loom
that superiority whieh they have in strength over hemp.
Theiy whiteness and silky appearance give reason to hope
that cloth made of thenr will exceed in beauty that manu-
factored from flax.

All the dresses which we purchased frorn the savages of
New Zealand were made from the fibres of their flax. To
eords of the same substance they had attached different or-
naments, among which were pieces of human bones,. and
which were suspended on their breast as a kind of trophy.
They seemed to attach great yalue to them, and were very
anw:lling to part with them.

Their ishmg-lines were formed of two flaments twisted
together; but their nets were made from the leaves of 2
plant separated into filaments, without any other prepara-
tion. As their nets are of prodigious extent, for the pur-
pose of fishing at a great distance from the coast, these
zavazes do not make them of ropes, because this labour
would require much time, and they besides find that their
flax employed in this manner 1s sufficient.

Ali the piroguas which approached us had on board men
armed for the most part with stones, some of them of gra~
nite, and others of serpentine, which they had attached ta

their

Geological Delineation of South America. 347

their wrists with cords of the Phormium tenax ; but I must
ebserve that these were only defensive weapons, for they
did every thing in their power to engage our confidence,
and soon consented to exchange these weapons ‘for our
hatchets, and for other instruments of iron, on which these
warlike people set great value. ;

It follows from the experiments, the results of which J
have here given, Ist, that the strength of the fibres of the
aloe being equal to 7; that of flax is represented by 1135
that of hemp by 161; that of the flax of New Zealand by
23-5,, and that of silk by 34. But the quantity they stretch
before they break is in another proportion ; for that of the
filaments of the aloe being equal to 2}; that of flax is
only 4; that of hemp 15 that of the flax of New Zealand
11; and that of silk 5. od, That great advantages will re-
sult from the cultivation of the New Zealand flax in France,
where it will thrive exceedingly well,

ee
NE —————————————— ee

LXIV. Sketch of a Geological Delineation of South Ame-
rica. By F. A. Von Humpouipr*,

Sixcr I sent to Madrid the two first sketches af a geolo-
gical delineation of South America, from the Caraccas and
Nueva Valencia, I have travelled 1200 miles, and described
a square between Caribe, Portocabello, Pimichin, and Es-
meralda, a space comprehending above 49000 square miles,
for I am not acquainted with the land between the moun-
tain Parea and Portocabello, and between the northern
coast and the valley of the Black river. _ In consequence of
the great circumference of this district, [ must content my=
self with delineating it in a general manner, and to avoid
details, with describing the construction of the earth, the
declivity of the land, the direction and inclination of the
mountains, their relative ages, their similarity with the
formation of those in Europe. These are the circumstances
most necessary to be known in this science. We must
proceed in mineralogy as in geography ; we are acquainted
with stones, but not with mountains ; we know the mate-
rials, but we are ignorant of the whole of which they form
component parts. I wish I may be able, amidst the variety

» This sketch is an-extract from a paper transmitted by M, Von
Humboldt from South America, together with a geolovical collection, to
the directors of the cabinet of natural histery at Madrid. It was sent *
a'so by M. Von Humboldt to Delametherie, and inserted by him in the
youn de Physique, Vil. 53- p+ 3% sities

of

$48 Geolasical Delineation of South America.

ef the objects which occupy my attention during my tra~
yels, to throw any light on the structure of the earth.
The lahorious journeys which, for eight years, [have made
through Europe, had no other object ; and if I have the
good fortune to return to Europe, and to recover my geo-
logical manuscripts which [ left behind me in France and
Germany, I shall venture to give a sketch of the structure
of the earth. What I have long said, that the direction
and inclination, the rising and falling of the primitive
strata, the angles which they form, with the meridian of
the place, and with the axis of the earth, are independent
of the direction and depression of the mountains; that they
depend on laws, and that they observe a general parallelism
which can be founded only in the motion and rotation of
the earth. What Freicsleben, Von Buch and Gruner have
proved better than 1 will be found confirmed, namely, that
the succession of the alluvial strata, which was considered
as a peculiarity of certain provinces, such as Thuringia and
Derbyshire, takes place generally, and that there appears
an identity in the order of the strata (see Plate IX.) ; from
which -there is reason to conclude that the same deposition
has been effected at the same time over the whole surface of
the earth. All these ideas are of the greatest importance,
not only to the philosopher, who endeavours to elevate
himself to general principles, but also to the miner, who
must conceive in his mind what he has not before his eyes,
and guide himself by analogy deduced from actual ex-
perience.

Before I describe the situation of the mountains which I
have observed from the coast to the province of Venezuela,
I shall. give a general view of the form of this continent.
Unfortunately there are no early observations to serve as a
eround for this description. For half a century past many
accidental observations respecting this land have been col-
lected, but nota single idea relating to its geology has been
made known. ‘The great genius of Condamine, the zeal
of Don George Juan de Ulloa, weuld certainly not have
left us in the dark on this subject, had mineralogy been
more cultivated at the time when they wrote. All that
could then be done was to measure and to take levels. As
they were employed on the high eordillera of the Andes,
which extends north and south from Zitara, as far as Cape
PiJar, and beheld with wonder the irmmense height of the
mountains, they forgot that South America exhibits other
cordilleras, which extend east and west parallel to the
equator, and whieh, on account of theirheight, deserve as

‘ much

Geological Delineation of South America, 349

much the attention of naturalists as the Carpathians, Cau-.
easus, the Alps of the Valais, amd the Pyrenees. The
whole immense tract on the west side of the Andes, which
extends obliquely to the coast of Guiana and Brasil, is de-
scribed as a low plain, exposed to the inundation of the
rivers. As only a few Franciscan missionaries and a few
soldiers have been able to penetrate over the cataracts to
Rio Negro, the inhabitants of the coast of Caracas ima-
gine that the immense plains (the Llanos de Calabozo, del
Guarico, and de Apure) which they see. to the south, be-
yond the valleys of Aragua, extend without interruption to
the Pampas of Buenos-Ayres, and to the country of the
Patagonians; but the extent of these plains is far frony
being so great; they are not uninterrupted plains, they are
rather phenomena of the same kind as those presented by
Canada and Yucatan, the Island of St. Domingo, the north
of Sierra de St. Martha, the province of Barcelona, and the
Jand between Monte-Video and Mendoza, New Holland,
‘the eastern part of Hungary, and the country of Hanover:
They are separated from each other by the cordilleras, and
are as far from lying in the same plane as the desarts of
Africa, and the steppes of Tartary, which rise by grada-
tions, according to the distance from the sea coast.

When one considers the irruptions which the North Sea,
the Mediterranean, &c. have made into the old world, the
direction of its cordilleras appears not to be very different
from that of those in the new world, as most naturalists
have asserted. We are acquainted also with the traces of
several high chains of mountains which extend from north
to south, and run out from those which extend east and
west. The garnet and micaceous schistus of Norway,
Scotland, Wales, Brittany, the province of Gallicia, Alem-
tego, Cape Bogador, ([ have found the same with granite
on Teneriff,) the upper part of Guinea, Congo, and the
‘Table Mountain, as also the original mountains of Oren-
burg, Caucasus, Lebanon, of Abyssinia and Madagascar,
scem at first to haye formed nothing else than two large
eordilleras parallel to the meridian.

In.the new world these cordilleras run parallel to the
meridian from Cape Pilar to the north of California beyond
Nootka and Prince William’s sound towards the Aleranhey
mountains, which were discovered in 1792 by Mr. Stewart
on his journey to the sources of the Missoury, the northern
part of the Andes, which is inhabited by Indians nearly as
much civilized as the Peruvians were fifteen hundred years
agy. From this cordillera proceed ramifications of the

original

$50) Geological Delineation of South America:

original mountains which extend from west to east. With
those of North America [ am not acquainted, but it appears
that some exist in Canada under the latitude of 50° and
42° north latitude, as in the destroyed continent of the
Gulph of Mexico under 19° and 22°; as is proved by the
mountains of Cuba and Saint Domingo. In South Ame-

rica there are three chains of original mountains which run
parallel to the equator: the chain of the coast under 9° and
30° ; that chain which is in the great cataracts of Autures
{in latitude 5° 39’) is between latitude 3° and 7°; and that
in’ Maipure in 5° 19’ 50”, which I therefore call the chain
of the cataracts or that of Parime, and the chain of Che-
quitos under 15° and 20° south latitude.

These chains in the old continent on this side of the
western ocean can be traced, and it is seen how the origmal
mountains of Fernambouc, Minas, La Bahia, and Janeiro,
correspond, under the same latitude, to those of Congo, as
the immense plains near the river Amazon lie opposite to
the plains of Lower Guinea, the eordillera of the cataracts
opposite to those of Upper Guinea, and the Llanos of the
Mississippi, since the irruption of the Gulph of Mexico, a
property of the sea, opposite to the Desart of Serah. This
view will appear to be less hazarded when one reflects in
what manner the old continent has been separated from the
riew one by the force of the water. ‘The form of the coasts,
and the sahent and: re-entering angles of America, Africa,
and Europe, are a sufficient proof of this catastrophe. What
we call the Atlantic ocean is nothing else than a valley
scooped out by the sea. The pyramidal form of all the
continents with their summits turned southwards, the great
flattening of the earth at the south pole, and other phzeno-
mena, observed by Dr. Forster, seem to show that the in-
flux of the water was from the south. On the coast of
Brasil, from Rio Janiero to Fernambouc, it found resist-
ance, and taking a direction from the latitude of 50° north
towards the north-east, where it scooped out the Gulf of
Guinea near Loango Benin and Mine, it was obliged by
the mountains of Upper Guinea to direct itself north-west,
and separated,to the latitude of 23° north,the coast of Gui-
nea from Mexico and Florida. The force of the waters was
still broken by the cordillera of the United States of Ame-
rica, and once more turned- towards the north-east, and
seems to have spared less the western coast of Europe than’
the northerrrof America. The least breadth of this channel
is at the Brasils and Greenland ; but, agreeably to the geo-
graphical history of plants and animals, 1f seems: to ng

een.

Geological Delineation of South America. 35%

been formed at a time when the organic creation had not
been properly expanded. It would be of great importance
to geolegy if a sea voyage were undertaken, at the expense
of some government, te examine the rising and depression
and the relative situatien of the mountains to the salient
and re-entering angies of America and Atrica. Lhe same
analevy would be found kere as is observed in the English
Channel, in the Sound, the Straits ef Gibraltar, and the
Hellespont; small<creeks which are as new as the secondary
formation of the chalk recks of Jura, of Pappenheim, Le
Mancha, Marseilles, Derbyshire, and Suez, whick have all
been produced at the same time by precipitation.

Of the three cordilleras of primitive mountains whick
traverse South America from west to east, the most north-
erm, that of Venezuela, is the highest, but the narrewest.
The real chain of the Andes extends from the large plain
of Quite, threugh Popayan and Choco, to the western side
of the nver Atrato (er Rio San Juan), between the valley
of Tatabé, in the provinces of Zitara and Biruguete, to-
wards the isthmus, where it fornas a mountainous district
of not more than two or three hundred toises in height on
the bank of the Chagre. From these Andes arises the cor-
dillera on the coast of Venezuela. Rows of mountains
higher, but forming groups less regular, extend on the
east side of the Rio Atrato under the name of the Sierra de
Abibé and the Montes de Cauca, through the high savan-
nahs of Jelu towards Magdalen mver and the province of
St. Martha. The cordillera of the caast eontracts itself Jike
that of the Gulph of Mexico, approaches nearer to Cape
Vela, and then proceeds first from south-south-west ‘to
north-north-east, and then from west to east to the ridge
of Paria, or rather to the Punta de la Galera in the Island
of Trinidad. its greatest height is found at that place
where it has the name of Sierra de Nevada de St. Martha in
tatitude 10° 2’, and of Sierra Nevada de Merida in latitude
8° 30’; the former is about 6000 the latter 5400 Spanish
ells (waras), or 2350 toises in height. “The Paramo de la
fiosa and de Maenchi, and also the mountain of Merida,
are continually covered with snow: boiling water (with
hydrogenated sulphur) issues from their sides, and they
exceed in height the Peak of Teneriff, and are, perhaps,
equal to Mont Blanc, which has been more accurately near
sured. These colossal masses and St. Martba stand almost
insulated, being surrounded by few high ridges. To the
west of Santa fé, or as far as the Sierra of Zuindia, no
enow-clad peaks are seen, and the Sierra Nevada dg Merida

i ; stangds

352 Geological Delineation of South Americas

stands at the edge of the plain of Caracas, which is starecly
forty toises above the level of the sea. Mont Blanc, which
terminates the high ridge of the Alps, exhibits the same
phenomenon. The altitude of the highest mountains, ©
however, is so yery small in proportion to the magnitude
of the earth that it would appear that very small local causes
ought to have accumulated more matter in these points,
That part of the cordillera of the coast which lies to the
west of Maracaybo-Sees, and joins the Andes, has large
valleys extending from north to south, such as that of Mag-
dalena, of Cauca, of Saint George, of Sinu, and Atrato.
They are very long and narrow, but covered with wood.
On the other hand, that part of the cordillera which ex-
tends from Merida to Trinidad incloses three valleys lying
east and west, which show by certain signs, like Bohemia,
or the Haslithal of Swisserland, that they have formerly
been lakes the water of which has evaporated or run off by
opening for itself a passage. These three valleys are in-
closed by the two parallel rows of mountains into which
the cordillera of the coast divides itself, from Cape Vela to
Cape Codera; the northern row is a continuation of Saint
Martha, the southern a prolongation of Sierra Nevada de
Merida. ‘The first extends through Burburuta, Rincon del
Diablo; through the Sierras de Mariara, the mountain
Aguasnegras, Monte de Arila, and the Silla de Caracas, to
Cape Codera. The second from three to four miles more
to the south extends through Guigui, La Palma, the high
summits of Guairaima, Tiara, Guiripa, and the Savana de
Ocumare, as far as the mouths of the Tuy. These two
chains unite with two arms which run from north to south,
like, as it were, dykes, by which these old lakes were con-
fined within their boundaries. These dykes are, on the west
the mountains of Carera, Tonto, Saint Maria, Saint Phi-
lips, and Aroa; they separate the Llanos de Monai from
the valleys of Aragua: on the east they are the naked sum-
mits of Los Teques, Coquiza, Buena Vista, and the Altos
de S. Pedro, by which the valley of Aragua or the sources
of the Tuy (for there is only one valley between the bottom
of Coquiza or the Hacienda de Brisenno to Valencia) from
the valley of Caracas. On the east from Cape Codera the
greater part of the cordillera of the coast of Venezuela was
destroyed and laid under water by the great catastrophe
which formed the Gulph of Mexico. The rest of it is di-
stinguished in the high mountain peaks of the Island of
Margaretha (Macanao and the Valle S. Juan) and in the
cordillera of the Isthmus of Araya, which contains the
3 micaceous

Geological Delineation of South America. 35

micaceous schistous mountains of Maniguares, Chuparipari,
Distilador, Cerro-Grande, the mountain of St. Joseph and of
Paria; the remainder I have accufately examined, and found
in them the same structure, the same direction, and the same
inclination of the strata. The three hollows, or valleys of
Caracas, Aragua, and Monai, are remarkable on this ac-
count, that the level of them is above the surface of the
sea; they become lower by gradations, and the highest step
is the eastern, which may serve as a proof that they were
formed at an earlier period than the Llanos, whose decli-
vity proceeds from east to west, like the whole continent
of South America. By repeated barometric measurement
I found the height of the valleys of Caracas to be 416
toises, of Aragua 212 toises, above the surface of the sea 5
the Llanos of Monai, the western bason, appears to have
an elevation of no more than 80 or 100 toises. The valley
of Caracas has once been a lake, which formed for itself
an effux through the Quebrada de Tipe, Catia, and Rio
Mamon ; the bason of Aragua appears, on the other hand,
to have become dry by gradual evaporation ; for the remains
of the old water (loaded with muriate of lime) are still seen
in the lake of Valencia, which becomes less every year,’ and
discevers islands which are known under the name of Apa-
recidas. The height of the cordillera of the coast is com-
monly from 600 to 800 toises; the highest peaks, Sierra
de Nevada de Merida and the Silla de Caracas, (to which
we undertook a laborious journey with our instruments)
are 2350 and 1316 toises in height. To the west they al-
ways become lower, and the height of Cape Codera is only
176 toises. The Macanao, on the island . Margaretha,
which I measured trigonometrically, is not more in height
than 342 toises ; but this speedy depression takes place only
in the primitive mountains of the cordillera. On the
eastern coast secondary accumulations of lime rise from
Cape Unare to a more considerable height than the gneis
and micaceous schistus ; these calcareous rocks, which are
covered with sandstone of a calcareous base, and which
accompany the cordillera of the coast in its southern decli-
vity, are very low on the side towards Cura, but rise in a
mass towards the eastern extremity of the continent.
. In Bergantin they are 702 toises high, in Coccollard 392,
in Cucurucho du Tuminiquiri:(the highest summits of the
province of Cumana) 976 toises, and the pyramid of the
Guacharo rises above 820 toises: from Cape Unare they
form a separate ridge of mountains, in which the original
ridge totally disappears ; they are connected also with the
Vou. XVII. No. 68. Z migaceous

3S4 Geological Delineation of South America.

micaceous schistous cordillera of Maniquare and Paria only
by the Cerro de Meapire, which, analogous to the branches
of Torito and los Teques, which separate the basons of
Monai, Aragua, and Caracas, extends north and south:
from Guacharo and Catouaro; to the mountain Pariay and
separates the valley of Cariaco (the dried up bank of the
Gulplv of Cariaco) from the valley of St. Boniface, which:
formerly belonged to the Golfo Triste. It will be secm
hereafter, that the accumulation of calcareous formation
on ‘the eastern. part of the coast of this country seems to
Have been more exposed to earthquakes; and that the Cerro
de Meapire, at the time of the irruption of the Gulph of
Cariaco, and the Golfo Triste, prevented the water trom
converting the land of Araya and the ridge of Paria into an
island. e

The declivity of the cordillera of the coast of Venezuela
is gentler towards the south than towards the north, which
is particularly striking when one descends ‘from the heights:
of Guigue, through St-Juan, Parapara, and Ortiz towards
the Mera de Paja, which belongs to the great Llano de
Calabozo. The northern declivity is every where very
steep, and there is scarcely foundy Mont Blane excepted,.
above Courmayeur, a more frighful precipice than the per-
pendicular wall of Silla de Caracas, beyond Caravalledo,.
which rises to the height of 1300 toises. An accurate mea-
surement of this wall of rock was of great importance to:
navigators, as they could find its distance from the coast
only by taking the angle of its elevation: its longitude,
therefore, of 60° 37’ 32” west from Paris, will enable then:
to discover it.

The phenomenon of a mote gentle dechivity towards the
south seems to contradict the observations made in other
cordilleras of the earth, as itis asserted that they all decline
more abraptly towards the south and west. ‘This contra-
diction, however, fs only apparent as the northern part of
the cordillera, during the great catastrophe which produced:
the Gulph of Mexico, was torn away by the foree of the
water; and therefore the northern: declivity might at that.
tinie be gentler than the southern.

If the form of the coast be considered, it appears to be
pretty regularly indented. The headlands of Tres Puntas,
Codera, S. Roman, and Chichibacoa, on the west, from
Cabo dela Vela, form a row‘of promontorics, the western
of which runs more to the north than the eastern. To.the
windward of each of these capes a creek has been formed;
and one cannot help seeing, in this singular formation, the

pat, ‘a action

"

Geological Delineation of South Amtricas 355

attion of the tropical currents; which may be called the
currents of the earth’s rotation; an action which shows it-
self also in the direction of the coast from Cuba; St. Do-
mingo, Porto Rico, Yucatan, and Honduras; as in the se-
ries of the windward islands Grenada; Orchila, Rocca, Aves,
Buenos-Ayres, Curacoa, and Aruba, the ruins of the cor-
dillera ftom Cape Chichibacoa, which are all parallel to
the equator. It was this headland of Chichibacoa, not-
withstanding its inconsiderable height, which by its resist~
ance to the influx, preserved the kingdom of New Grenada
from losing so much land as the general governnient of
Caracas. aay

The second original cordillera of South America, which +
T have called the cordillera of the Cataracts of Orinoco, is
yet very little known. During the journey which we made
on the Black River, to the borders of the Great Bara, we
travelled more than 200 leagues, first from north to south,
from Cerro de Uruanato Atabapo and Tuamini; then from
west to east, from the mouths of the Ventuari to Vulcan
de Duida, which I have found to be in latitude 3° 13’ 26”,
and longitude 60° 34’ 7” west from Paris. Since the jour-
ney of Messrs. Ituriaga and Solano, a passage over these
cordilleras, which may be called also Parima or Dorado
(golden), a name which has occasioned so much misfortune
in America, and so much ridicule in Europe, has been pos-
sible; but as all the European settlements on the Alto
Orinoco, and the Rio Neero (Black River), contain at
this time no more than 400 Indian families, and as the
way from Esmeralde to Erevato and Caura has been totally
lost, our researches in a land so little civilized, presented
more difficulties than Condamine experienced during his
tedious navigation on the river Amazon, the banks of which
for many years have been inhabited.

The cordillera of the Cataracts or of Parima separates
itself from the Andes of Quito and Popayan, in the longi-
tude of from3°to 6°. It extends from west to east from
Paramo de Tuquillo and St. Martin, or the sources of the
Guaviare, the theatre of the gallant deeds of Philip de Urre,
and the old residence of the Orneguas, through Morocote,
Piramena, and Macuco, stretching through the country of
pe Indians of Guajibos, Sagi, Dagueres, and Poigraves

ccording to the direction of the great rivers Meta, Vichada,
Zama, Guaviare, and Ymerida, in the longitude of 70° west
from Paris, between the high summite of Uniama and Cu-
navami. They form the Raudals of Atures and Maypuré,
tremendous waterfalls; which afford the only passage by
Z2 which

350 Geological Delineation of South America

which one can penetrate into the interior of the land in the
valley of the River Amazons. .

These cordilleras of the Cataracts rise from the longitude
of 70°, and spread out in such amanner that they compre-
hend the whole immense tract of country between the rivers
Caura, Erevato, Cavony, Paraguamusi, Ventuari, Jao, Pa-
damo, and Manariche, and then ascend south towards the
sourees of the Pasimona, Cachevayneris, and Cababury,
towards the forests, where the Portugueze, penetrating into
the Spanish: district, collect the best sarsaparilla known
(Smilaa Sarsuparilla,.Lrxx.). In this district the cordilleras
of the Cataracts are above 120 miles im breadth. Their
continuation more towards the east, between the Jongitude
of 68° and: 60° west from Paris is little known, I pro-
ceeded witly astronomical. struments only, as far as Pio
Guapo, which discharges itself into the Orinoco, opposite
the Cerro de la Cauclilla, in longitude 68° 33” west from
Paris. The Indians of Catarapeni and Maquiritares, who
reside in the small mission of Esmeralde came fifteen males
farther east over the mountains Guanaja end Yamariquin'
to the Canno Chiguire; but neither the Europeans,.nor [n-
dians with whom Europeans have had any intercourse, are
aequainted with this source of the Orinoeo, which: is here
called Canno Paragua, and is scarcely 150 or 200 toises 1m
breadth, whereas at Boca de Apuré, in latitude 7° 32’ 20",
it is 4632 toises, as I myself found. The wildness of the
Indians of Guatcas, who are only four feet im height, but
who ave a very white and warlike people, and particularly the
savage state of the Guajaribos, greater men-eaters than any
of the other nations which we visited, prevent any one from:

_pehetrating over the small cataracts (Raudal de Guajaribos)
east from Chiguire, unless a military expedition were un-
dertaken on purpose. But by the wonderful journey
undertaken. by D. Antonio Santos, who marned Onotho,.

ud who dressed sometimes as a Carib, and sometimes as
a. Macacy, whose languages he spoke, from Orinoco (the
mouth of the Rio Caronis). to the small lake Parima and.
the river Amazon, we have obtained: information respect-
ing the continuation of the cordillera of the Cataracts.
Under the latitude of from 4° to 5° and longitude 63°, it
becomes so narrow that it is scarcely 60 miles in breadth.

assumes here the name of Cerrania:de Quimiropaca-an

Pacaraimo, and forms. a chain ef not very high ridges, by
which the waters were divided. The water of the northern

‘declivity, the Nocapray, Paraguamuci, Benamo, and Ma~
zurini, flow towards the Orimoco and Ria Esquibo; the

waters

Apparatus for preparing Hluoric Acid, Sc. 357

waters of the southern, the Rio Cururjcana, Parime, Madan,
and Mao, pour themselves into the River Amazon. Some
slegrees further towards the east, the cordillera again extends
in breadth as it ascends southwards towards the Cannmo Pa-
rara elong the Mao. It is here that the Dutch give to the
erro d’Ucuamo, the magnificent name of the Gol@-
Mountain, or Dorado, because it consists of a very shining
micaceous schistus, a fossil which has brought into celebrity
the small island of Ypamucena in the lake of Pazima.

On the east from Rio Esquibo, or on the other side of
the land of the Aturajo Indians the cordillera ns south- ~
east as it unites with the garnet mountains of the Dutch
and French Guiana, which are inhabited by a mixture of
Negroes and ‘Caribs, and give an origin to the rivers Be:-
bice, Surinam, Marony, Aprouague, and Oyapock. The
last mentioned ridge of mountains extends very much: its
gneis appears at Baxo Orinoco, in latitude 8° 20’, between
the mouths of the Upata and Acquire, and in latitude
2° 14’ on the north side of the river Amazon, in the moun-
tains of Fripeupon and Maya.

Suchis the form of the great cordilleras of the Cataracts,
which are inhabited by a great number of uncivilized
savages, little known to the Europeans. I must here ob-
serve, that in this description I have followed my own
observations only, and the notices we obtained from the
Indians, as also the observations of D. Antonio Santos, and
the companions of his journey, who dictated to their
friends. The maps of this part of the continent are en-
tirely false, and the map added to the history of the Evir-
coco by P. Caulin, a work in other respects meritorious, is
by our last observations some degrees more wrong in longi-
tude and Jatitude than the map published thirty years be-
fore by d’Anville. All the Indian names in it also are mu-
tilated, and mountains and rivers are delineated where none
exist ; a defect the more pardonable as the author was never
beyond the waterfalls of Orinoco, nor at the Rio Negro.

[To be continued. |

LXV. Description of Mr. Ricuarp Kxicut’s Apparatus
Sor preparing Fluoric Acid, and for Etching on Glass.

.

I HE fluoric acid, as every chemist knows, has the pro-
perty of dissolving and volatilizing silex ; therefore vessels
made of glass, which consists chiefly of silex, cannot be

‘conveniently emploved to preptre or retain this acid. The
, Z3 common

398 Apparatus for preparing Fluoric Acid, Be.

.common method of preparing it is by employing a leaden
_retort into which’ is put a quantity of fluor spar in powder,
and an equal or a greater quantity of sulphuric acid: a
gentle heat is then applied, and a gas comes oyer, which
may be received in the usual manner into jars standing over
mercury. This gas is the fluoric acid. Or the gas may be
“made to pass into a receiver containing water; in which
case the acid is obtained dissolved in the water.

Mr. Knight’s apparatus consists of a leaden body A,
fig. 1. (Plate VIII.) furnished with a wide groove, aa, round
its mouth. The body A is fitted into the mouth of an-
other vessel B, into which is put water, the medium through
which the heat-is applied to the contents of A. To the
body A is fitted a cover C, which rests on the outer edge
of the groove aa, and also enters into the groove, which is
filled with water when the apparatus is to be used.

If fluor spar in powder he put into A, sulphuric acid be
poured over it, and heat be applied to the vesscl B, the
water therein will transmit heat to the materials and the
gas will ascend into the head C, where it will be absorbed
by the water in the groove wa, and form liquid fluorie acid.
If a piece of glass, covered with wax, or any proper etching-
ground on which a design has been traced with a sharp
point, be exposed in the head C to the action of the acid
gas, the parts of the glass that have heen laid bare will be
corroded ‘in the same way as copper is by aquafortis when
etched, In this case the fluoric acid always leaves the sur-
face it has acted upon dull and opake. When liquid fluoric
acid is employed instead of the gas, the bottoms of the lines
are transparent. ;

For etching on glass, however, with the gas, the follow-
ing modification of Mr. Knight’s apparatus seems preferable
to the former :—The materials are to be put into the leaden
vessel A, fig. 2, which has.a coyer fitted into a groove
(filled with water when made use of), and a pipe in the
coyer by which it 1s connected with another leaden vessel D
(furnished with a cover), into which the glass intended to
be acted upon by the acid is put resting on a strip of lead
bent into any form that may not interfere with the design
on the glass. In this case, as in the former apparatus, the
vessel A is to be heated by water in an exterior vessel.

Instead of drawing with a sharp point through an etch-
ing-ground when the gas is to be employed, another pro-
cess may be followed ;—With a hair pencil apply a proper
yarnish to those parts of the glass which are wished to be
defended from the action of the acid: in a few maments
.* € = 2 9°7 ‘ie I s ae Ls - . ° '? the

Description of the Vulture of Pondicherry. 359

the exposed surface will become comparatively dull; and on
removing the varnish from the other parts they will ap-
pear to have undergone some precess by which they have
received a higher polish than glass usually exhibits: for the
parts acted upon, though really dulled a little, will still ap-
pear transparent if the process has not been carried too far.

LXVI. Description of the. Vulture of Pondicherry. By
F, M. Daupin*.

Tr is not only easy to separate the vultures from other
birds of prey because they have the head or neck bare of
feathers, but they may be subdivided also into several sec-
tions, as some of them have caruncles while others are un-
provided with them.

The most remarkable species are met with among those
of the first section, but the one which hitherto seems most
worthy of the attention of ornithologists is the Oricow vul-
ture, discovered by Levaillant in Africa; for the aperture of
its ears is surrounded by a membranous caruncle, four lines
in height, nearly similar to an external ear, and which de-
scends downwards on each side of the neck. The head and
neck of this bird, very well preserved, may be seen in Le-
yaillant’s collection.

Sonnerat also discovered at Pondicherry another vulture
so similar to the oricou in size, dimensions, and principal
characters, that several naturalists have been of opinion
that this vulture of Bengal might be the female of the ori-
cou, for on each side of the neck-and a little below the car
it has a membranous caruncle turned downwards ; but as
these two vultures exhibit other differences more striking I
have thought it proper to consider these birds as two kin-
Ared species fT. ’

The vulture of Pondicherry differs from the oricou de-
scribed by Leyailiant, 1st, By its caruncles, which are
placed below the ear: 9d, By its face, furnished with stitf
hairs, which surround the tympanum, cover the checks,
and are proportionably longer than on the neck: 3d, By its
breast, covered with ash-coloured silvery down, short and
compact; 4th, by the whitedowny cravat placed on each side

* From Annales du Muscum National d'Histoire Naturelle, No. 4-

+ Levaillant, Histoire Naturelle des Oiseaux d'Afrique, pl. 9 Dau-
din, Traité d’Ornithologie, vol. ii. pl. 10., Wautour Oricou. (Yudiur
¢uricularis), ps its Vautour de Pondicherry (udtur pouticerianus).

Z4 | of

360 Twelfth Communication from Dr. Thornton,

ef the lower part of the neck: 5th, By the plumes of the
whole lower part of the body, which are very short, and
not long and unravelled as in the oricou.

The rest of the plumage is of a very dark colour; the bill
and feet are yellow.

The individual from which the annexed engraving was
taken (Plate X.) is now in the National Museum at Paris,
and was found in India by Massé, the naturalist. The de-
scription published by Sonnerat is completely applicable
to the individual found by Massé ; but the figure 1s so in
correct that Mauduyt did not venture to mention the ca-
runcles of the neck in his Dictionnaire Ornithologique.

a

LXVII. Twelfth Communication from Dr. THORNTON, 0”
Pneumatic Medicine.

To Mr. Tilloch.
SIR, No. 1, Hinde-street,
Manchester-square.
I Am happy to inform the philosophic world that the pneu-
matic practice is at this time advancing. Iam credibly inform-
edthat Dr. Baillie and Dr. Reynolds, physicians equally dis-
tinguished for science and humanity, have each ordered the
administration of the vital air. Several other practicioners
are following the same liberal course ; and it is probable that
this century will see the completion of my ardent wishes ;
namely, the establishment ‘of the virtues of the eérial re~
medics.
The First Case of the Application of Vital dir. -
To Dr. Thornton.
DEAR SIR, Conduit-Street, Jan. 12, 1804.
In compliance with your request, I sit down to state to
‘ou the case’ot Mrs. L. , the lady of L » Esq.
iving near Guildford. This lady laboured under a decline,
at a time when her husband was attending a course of Dr.
Priestley’s discoveries, nearly thirty years ago, at my lec-
ture-rooms, then in George-Street, Hanover-Square, soon
after those discoveries were made. The atrophy kept on
increasing for some time after, till her state made an emi-
nent physician of Guildford desire Mr. L—— ‘ to prepare
for the worst.”’ This alarm induced him to ask his physi-
vian, “ if some of those newly discovered airs might not
be usefully employed m her case.” His answer was:

*« Any thing might be tried, but he feared all would be to
no

On Pneumatic Medicine. ha 361

fo manner of purpose.” Mr. L—— immediately set out
for London, and requested I would fit up an apparatus for
Mrs. L——, to try the effects of the dephlogisticated air,
as it was then called. I immediately accompanied him to
the country. Here { ought to blush, and apologize to the
faculty, for having dared to employ a new medicine with-
out possessing any pathological knowledge: but the case
was desperate. An agonizing husband, determined to try
every expedient to save a beloved wife, could not fail to
rouse the utmost efforts of humanity; and the vital air ap-
peared to me not unlikely to produce relief, (if not acure,)
as I had often myself breathed it mixed with common air,
and found it very reviving. I therefore put a table-spoon-
ful of minium (red Jead) into a saucer, and poured upon it
as much vitriolic acid as would moisten it, and placed it
about a yard distant from the patient, that as the gas rose
it might be much diluted with the common air, so as not
to irritate the lungs. Finding no ill effects to arise, I re~
peated the same dose for a quarter of an hour on that day,
but placed nearer the nostrils, and she found herself better.
So encouraged, I pursued this practice for several days, till
I judged that she might draw the gas from a vessel con-
trived for this purpose, and still less mixed with common
air. Hercough was in:consequence considerably abated,
her breathing became very easy, she felt herself after each
inhalation revived, and was evidently so much mended that I
took my leave of the lady, after having put the family into
the way of continuing on the process. This practice I un-
derstand was persisted in for some time, till Mrs. L was
established in her health. I then lost sight of the family
for several years, (Mr. and Mrs. L—— having gone
abroad *,) when I was at last agreeably surprised by a call
from Mr. L——, who said, ‘* he was returned to Eng-
Jand, and was come to thank me for a wife and two chil-
dren.” Only three years ago this lady with her husband
attended my lectures, and had continued since in perfect
health. I have the honour to remain, dear Sir,
With much respect and esteem, yours, &c.
A. WALKER.

Olservations on this Case by Dr. Thornton.

1. As the attending physician is dead, I am unable ex-
actly to ascertain all the symptonis of the disorder here

* Upon putting the question, neither of the Mr. Walkers have any
idea that this expedition was undertaken for the purposes of health.
mentioned ;

362 Twelfth Communication front Dr. Thorntor,

mentioned ; but the debility must have been great, and the
danger ajarming.

2. <* After each inhalation of the superoxygenated air,
the patient was revived.” Mr. Walker also mentions a like
effect, from mhaling an atmosphere of a higher standard,
Dr. Priestley likewise experienced the same good effect, and
ventures to prophecy “ that in time the inhaling of oxygen
air would become a fashionable article of luxury. Hi-
therto,” says this philosopher, ‘ only two mice and
myself have had the pleasure of breathing it.” In my first
communications, published by Dr. Beddoes, December
2793, I have stated the same circumstance, and add, by
way of P.S. to my second letter, “I cannot at this time
Zorbear mentioning the instance of a clergyman, the Rey,
Mr. T—r—r, whe laboured under dyspepsia, and great de-
pression of spizit-. He had exhausted the whole catalogue of
tonics, without. experiencing much benefit. As nothing
eonduces more towards good spirits and quick digestion,
than. a clear pure air, I accordingly ordered him to inhale
vital air, blended with a proportion of atmospheric. The
foad on his chest, as he termed it, was removed; his ap-
petite was quickened ; his. spirits were raised. to the pitch I
would term gaiety ; and, as he informs me, he felt the
same night so: strong a desire to go to the play, to which
he had nat been, not feeling the least inclination towards
such an excursion, for a long time, that he went that night ;
and declares, that he is. fully convinced that no inducement
could have got him thither, had he not previously inhaled
a more exalted atmosphere.”? About the same time Dr.
Biggs was a patient of Dr, Beddoes, and being a physician,
the more credit will be allowed to his assertion. He says,
*< after breathing the superoxygenated air, I found my dit-
ficulty ef breathing much relieved in three days, and before
the expiration of eight days it entirely ceased. Before this
time I had been subject to coldness of the extremities,
which now went off. I could even sleep, with fewer bed-
clothes. I had also a greater flow of spits.” Dr. Maxe
well, and Dr. Goodwyn, infused 4 pints of vital air into the
cellular texture of several dogs, by making an insertion
under the skin. After the first effects of the operation was
ever; the animals appeared “ exceedingly lively’ (maxima
alccritas.) (Vide Dr. Maxwell’s Thesis, published in 1787,
¥dinburgh.} The celebrated Dr. Beddoes, in his history of
that remarkable case, where a person subject to epilepsy
was thrown into an unusual fit, says, ‘ I was not prepared
to expect any thing like intoxication from an overdose of
f 5 ) , diluted

On Pneumatic Medicine. 363

diluted oxygen air, especially as in the instances where T
have known more inspired in the same time, nothing be~
yond a sensation similar to the alertness of healthy children
was felt. (Vide Letters of Dr. Withering, &c. to Dr.
Beddoes, p. 33.) Thus it is a common remark, after
coming out of vitiated air in a crowded room, how grute-
ful how reviving is the air! The western breeze in spring,
replete with oxygen air is even a theme for the poet’s song.
There are many who do not feel refreshed unless they use
exercise in the open air. Besides the nerves,
' 3. That the inhalation of oxygen air acts on the circula-
tion, appears to be proved from the following particulars.
From experiments with animals we learn the following very
curious facts :—‘ I observed,” says Dr. Beddoes, ‘¢ signs af
much stronger irritability in the right auricle and ventricle,
in the diaphragm and intercostal muscles of the oxygenated
rabbit; and, considering the force and frequency of the con-
ractions, the quantity of action would have been greater in
the oxygenated had the irritability continued five times as
long in the other. The speedier coagulation of the oxygen-
ated venous blood is, I think, also remarkable; and, as it
happened in three following experiments, was not acci-
dental. There was an alteration made also in the muscular
filre. Several persons, of whom all did not know the one
rabbit from the other, found the boiled flesh of the oxy-
genated, in both cases, more stringy and harder. The dif-
ference way most sensible in the young pair. The greater
stringiness was apparent in both these occasions to the eye.”
_ Jna society for philosophical experiments and conversa-
tions, Mr. Taylor’s pulse was first felt by Dr. Higgins, and
by many other members present with myself. It was only
64 previous to his inhaling 19 pints of pure oxygen air, al-
though he was healthy, and only 22 years of age. In the
minutes of our socicty, which are published (see p. 146),
it is noted, §* that during the respiration his pulse was
quickened to 90 beats in a minute, and considerably in-
creased in strength and fullness; but he felt o incopveni-
ence whatever. The vessel being charged again with nine-
teen pints of oxygen air, he respired these also, and his
pulse was now increased to 120 beats in a minute, and
vigorous withal: he felt 20, inconvenience, but had a sense
of unusual warmth in his lungs. In one hour after the ex-
periment, his pulse was returned to 64 beats, as before the
experiment.”—That evening Mr. Taylor appeared to me,
and others to be rather in fuller spirits. :

(The subject of the pneumatic practice will be resumed

in the next.
' ! LXVIII. Notices

(° 364 J

LXVIII. Notices respecting New Publications and the
Fine Arts.

A Practical Essay on the Analysis of Minerals, Pay. cal
ing the best Methods of analysing Ores, Earths, Stones,
inflammable Fossils, and Mineral Substances wm generat,
By Frepreric AccuM, 12mo.

Ma. Accum, to whom the public are under obligations
for a useful work of which we lately took some notice,
namely, 4 System of Theoretical and Practical Chemistry,
has brought forward the present essay, as he informs us in
his preface, by the express desire of a number of gentlemen,
to-whom he delivered a private course of lectures on prac-
tical chemistry. We have no doubt but it will meet with
a favourable reception, as it presents much useful informa-
tion on the subjects which it embraces. The following ex-
tract will convey some idea of the nature of the work :

General Analysis of Earths and Stones.

In the preceding pages we have considered earths and
stones solely with a view to discever their principal preva~
jent component parts, in order to determine therefrom the
genus to which the mineral belongs: we shall now enlarge
upon this subject more fully, by pointing out some general
observations, which may serve as a guide for separating all
the different earths that may exist in a coinerel witigaetelel
to our examination. In the analysis of earthy substances,
or stones, we must first attend to their solubility or insolu-
dility in acids; and with that view we divide them into two
classes, namely, earths and stones, which effervesce with,
and are either totally or nearly soluble in, nitric acid, di~
Juted with five or six times its weight of watcr; and such
as are not soluble in that acid. Suppose, therefore, that
the stone to be examined consisted of silex, alumine, mag~
nesia, lime, strontia, and barytes.

The methed of separating these different earths will be-
tome obvious from the following considerations :

Process I. Reduce a quantity of the mineral to powder,
ead try whether teffervesces with nitric or muriatic acid
dijuted in the above ‘proportions; if so, let a determinate
quantity be put into a tubulated retort of as little capacity
as possible, imimerse the neck of it under a cylinder filled
with water, and placed in the pneumatic apparatus.

If. Let-aquantity of muriatic acid be put at once through

3 L the

On the Analysis of Earths. 6%

the tubulure, or opening, at the top of the retort, and im-
mediately stop it so as to be air-tight.

ILI. When no more gas is liberated by the addition of a
fresh portion of acid, assist the action by heat, and transfer
the cvlinder containing the gas into lime water: the car-
bonic acid will now be absorbed; the loss of the whole
bulk, after deducting the air which was contained in the
retort, indicates the quantity of carbonic acid contained in
the stone.

IV. The substance from which the carbonic acid has been
expelled must be diluted with double its weight of water,
and filtered; the insoluble part, if any, put aside for further
examination. The solution may contain lime, magnesia,
alumine, barytes, and strontia.

V. In order to ascertain if barytes or strontia be present,
dilute a small portion of the solution with 24 times its bulk
of water, and drop into it a solution of sulphate of soda.
If barytes or strontia (or both) be present, a cloudiness will
take place, and a white precipitate will gradually be depo-
sited.

VI. Having thus investigated the presence or absence of
these earths, our next object is to separate them. Suppose
they should both be contained in the fluid? For that pur-
pose, add a solution of sulphate of soda till it produces no
further cloudiness ; when the precipitate has. subsided, col-
lect it on a filter, wash and dry it.

VII. Boil this precipitate, with four times its weight of
carbonate of potash, in a sufficient quantity of water for at
Jeast one hour, supplying this fluid as it evaporates, then
suffer the insoluble part to subside, and wash it.

VILL. Transfer the insolukle part of the last process into:
nitric acid of the specific gravity 1°4, diluted with an equal
weight of water. The carbonate of strontia which it con-
tained will be dissolved, but the barytes will not be acted
upon: the weight of the latter, deducted from the weight
of the whole, gives the quantity of each; or the two may
be separated by adding to the nitrie solution barytic water
till no further precipitate cnsucs: the barytes in this case
will seize the acid, and the strontia will be thrown down ;
but in this case it is essential that the nitric solution of the
earth is perfectly neutral, or has no excess of acid.

IX. The strontia and barytes being thus separated, heat
the fluid and drop into it a boiling solution of carbo-
nate of soda: the precipitate which falls down may con-
sist of all the remaining earths which were contained in the

solution

466 Anal. ysis of Earths.

solution, namely, lime, magnesia, and alumine. Ii order
to separate them, proceed as follows :

X. Boil the precipitate in a solution of caustic potash for
at least half an hour; dilute the fluid with water, and se-
parate the insoluble part by the filter, the alumine will now
be dissolved by the potash, arid the other earths remain un-
touched. ;

XI. To separate the alumine, neutralize the alkaline so-
lution by muriatic acid; a precipitate falls down ; wash it,
and expose it to ared heat? It is the alumine which was
contained in the mineral.

XTI: To separate the other earths, dissolve the residue of
Process % in nitric or mtriatic acid, evaporate the solution
to dryness, weigh the dry mass; and pour on it at least
double its weight of sulphuric acid, and heat the mixture
till no more white fumes rise. Digest the mass in twice
its weight of cold water, filter it; and dry the insoluble part
m a low red heat:

XII. The insoluble portion of the last process contains
the lime combined with sulphuric acid. To ascertain its
quantity deduct from its weight 59 per cent. ; the remainder
is the quantity of lime.

XIV. To obtain the magnesia, concentrate the fluid ob-
tained in the XIIth Process to one-third of its original bulk ;
make it boiling hot and decompose it by a solution of car-
bonate of potash; collect the precipitate, expose it to a red
heat till it does not effervesce by the addition of an acid.
It will then be the pure magnesia contained in the mineral:

Stones insoluble in Diluted Nitric and Muriatic Acids:

Process 1. Take a determinate quantity of the stone re-
duced to an impalpable powder, mix it with at least three
times its weight of potash, and fuse the mass thoroughly
im a silver or platina crucible. From the phenomena which
take place during this process, we may already form some
conjecture concerning the nature of the stone submitted to
examination. If the mass fuses completely, siliceous earth
predominates ; but if the fusion remains imperfect, and the
mass cannot be rendered liquid, the other earths are most
abundant. If it remains in a powdery form, and can partly
be rendered liquid, and if the bulk of the mass has been
considerably increased, then alumine may be expected to be
the most prevalent part. If the mass in the crucible be of
a brownish red colour, it contains oxide of iron: a bright
green colour announces the presence of manganese, ag

cially

Analysis of Stones. 367

cially if a small quantity of the mass, when dissolved in
water, communicates to that fluid the same colour. If the.
mass is of a yellowish green, the oxide of chrome may be
present.

J. When the mass has been thoroughly fused or kept
in a red heat for at least two hours, remove the crucible out.
' of the fire, and when nearly cold pour water into it oradu-
ally, in order to detach the mass from the crucible; transfer
the whole into a flask, pour four times its quantity, or more,
of water over it; boil the mixture for about half an hour,
and then suffer it to subside.

III. Having done this, pour gradually muriatic acid into
the before-obtaimed solution without previously separating
the insoluble part, if any. The first portion of acid which
is added occasions a flocculent precipitate, then an effer-
veseence takes place, and a copious precipitate immediately
follows; which, however, is no sooner formed than it js
redissolved. On adding more acid, the portion of the mass
which resisted the action of water, and which was not dis-
solved in Process II., will become dissolved. If it consists
of alumine it will be taken up silently by the acid; if it be
hme, barytes, or strontia, it will be dissolved with effer-
vescence.

Remark.—From the phenomena attending the process
of the solution of this mass in muriatic acid, some indica-
tions may be derived. If the solution be colourless the
Stone contains no metallic substance, or only a minute’
quantity. Ifits colour be purpleish red, it contains man-
ganese ; orange red is a sign of oxide of iron; gold yellow
shows chrome.

IV. To separate the different earths, &c. contained in the
solution, evaporate it to dryness; when the evaporation is
approaching towards its completion it assumes a gelatinous
appearance, it must then be diligently stirred with a glass
rod till it is almost dry.

V. Transfer the mass into a large quantity of water, boil
the mixture for a few minutes and then filter it, wash the
insoluble residue left on the filter repeatedly, dry it and ex-
pose it toa red heat; its weight shows the quantity of silex
contained in the stone. If it is pure silex it will be per-
fectly white, entirely insoluble in sulphuric, nitric, and
muriatic acids; if it be coloured it is contaminated with.
some metallic oxide, and shows that the evaporation to.dry-
ness has heen performed with too much heat. From the
metallic oxide it may be purified by digestion in muriatic
acid, and then washed and dried as before. ‘The acid ex-

pended

368 Analysis of Stones.

pended in washing may be added to the fluid which passed
through the filter im obtaining this earth.

VI. The fluid from which the silex has thus been ob-
tamed, is then to be concentrated by evaporation and
mingled with a heated solution of carbonate of potash till
no more precipitate ensues. The precipitate must be sepa-
rated by the filter, washed and dried. It may contain alu-
mine, lime, magnesia, glucine, and yttria, beside metallic
oxides.

VII. Transfer the precipitate obtained in the last process
into a solution of potash, and boil it for half an hour. If
alumine and glucine were present, they will both be dissolved
in the potash, while the other substances remain untouched
in the form of a powder.

VIII. To separate the alumine, decompose the solution
by the addition of an acid, taking care to add the acid em-
ployed in excess, so that the precipitate which first appeared
becomes redissolved. Having done this, drop into it a so
lution of carbonate of ammonia in such quantity that the
liquid tastes of it. By this addition the whole of the alu-
mine will be precipitated in white flakes, and the glucine
will remain dissolved provided the quantity of carbonate of
ammonia used be not too small. The liquid must now be
filtered, and the alumine washed, dried, and ignited ; its
weight may then be ascertained.

1X. The fluid from which the alumine has been sepa-
rated may be boiled for some time; the glucine, if it con-

“tains any, will be precipitated, which may be dried and
weighed,

X. The insoluble part left in Process VII may now con-
tain lime, magnesia, and some metallic oxide: Jet it be dis-
solved in diluted sulphuric acid, and the solution evaporated
to dryness ; on the dry mass pour a small.quantity of water,
and digest it for a few minutes; the water will dissolve the
sulphate of magnesia and the metallic sulphates ; but the
lime’ combined with the sulpburie acid will remain undis-
solved: let it be heated red-hot in a crucible, and the quan-
tity of lime determined, as directed before, page 143.

- Remark.—If yttria be suspected, let the residuum of Pro-
cess VII. be treated with carbonate of ammonia, which will
dissolve the yttria and leave the other bodies ; then proceed
as above. |

XI. The solution from which the lime has been separated
must next be copiously diluted with. water; add a small
excess of acid, and then drop into it a solution of carbonate
of potash as long as a precipitate ensues. This will sepa-

rate

and the Fine Arts. 369

rate the oxides of iron, chrome, and nickel; but the oxide
of manganese, and the magnesia, if any be present, will re-
main dissolved.

XII. To separate the oxide of manganese from magnesia,
pour into the fluid obtained in the last process hydrosul-
phuret of potash : the manganese will be precipitated, but
the magnesia will remain dissolved. The precipitated man-
ganese must be heated to redness, and weighed. |

XII. To the fluid of ‘the last process, from which the
manganese has been separated, add a solution of potash ;
the precipitate which now falls down is magnesia; let it
be washed, dried, and heated to redness.

XIV. In order to obtain the metallic oxides, boil the in-
soluble residue, left in’ Process X1, repeatedly m nitric acid
to dryness. .

XV. Transfer the dry mass into a concentrated solution
of potash. The oxide of chrome, acidified in the last process,
will thus unite to the potash, but the other oxides will remain
untouched; decant the fluid from the insoluble residue.

XVI..To separate the oxide of chrome, add to the solu-
tion muriatic acid in excess ; and evaporate the fluid till it
assumes a green colour: then, on adding a solution of pot-
ash, the oxide of chrome ialls down, because the quantity
of oxygen required for its acidification has been separated
by the muriatic acid: let the precipitate be dried and weighed.

XVII. Let the insoluble residue of Process XIV be next
dissolved in muriatic acid, and to the solution add liquid
ammonia in considerable excess: the oxide of iron will be
precipitated ; let it be washed, dried, and weighed.

XVUI. The oxide of nickel which remained in solution
on account of the excess of ammonia will now fall down:
on evaporating the fluid to dryness, its weight may be as-
certained in the same manner with the other ingredients,
and the analysis of the stone is now completed.

Elements of Galvanism in Theory and Practice; with @
comprehensive View of its History, from the first Expe-
riments of Galvani to the present Tine: containing also
Practical Directions for constructing Galvanic Apparatus,
and plain Systematic Insiructions for performing all the
various Experiments. Illustrated with Plates. By
C. H. Wirkinson. 2 Vols. 8vo.

The title of this work sufficiently explains its object. The
author, in his preface, mentions the sources whence he hes
chiefly derived his information, namely, the productions of
Sue, Reinhold, and Humboldt, and the Medical Journal,
Mr. Nicholson’s Journal, and the Philosophical Magazine ;

Vou, XVII, No, 68, Aa and

370 Notices respecting the Fine Arts.

and it is but justice to the author to say he has been very
industrious, having allowed nothing to escape him which
ought to appear in a work of the kind he had undertaken,
He divides the historical part of his work into two epochs ;
the first consisting of the various discoveries from the pe~
riod of Galyani to that of the Voltaic pile ; when the second
commences, which comes down to the present time. This
is followed by what the author calls his particular theory,
in which, however, several opinions are mentioned as new
which we have seen elsewhere, and some of which appear
to us to have been mentioned in the historical part as bang
entertained by others.

The language of the author is neat and correct, and the
work will afford a considerable portion of amusement te
readers in general, as well as to those whose pursuits render
it necessary for them to make themselves acquainted with
this new and interesting subject. |
The Soldier’s Friend: containing Familiar Instructions ‘to

the Loyal Volunteers, Yeomanry Corps, and Military

Men in general, on the Preservation and Recovery of

their Health. By Wit.i1am Buatr, A.M. &e. Se.

A New Edition. 12mo. ;

Mr. Blair’s exertions at the present crisis have been highly
meritorious. His gratuitous lectures to the volunteers will
be long remembered with gratitude by his countrymen, and
the present little volume will be well received by the public,
especially by those for whose service it is chiefly intended.
No military gentleman or volunteer ought to be without it.

The Conversion of Saul: engraved by HELLYER from «
Picture by Daves.

The composition, breadth of light and shadow, and other
points of excellence which are conspicuous in this print,
rank it among the finest productions of the British school.
It possesses a force of expression that must recommend jt
to all the lovers of true art, at the same time that the choice
of the subject, and its truly classical mode of treatment,
seem well calculated to ensure to it a general reception. The
style of the engraving, which does great credit to Mr, Hell-
ver, has not been excelled by any thing of the kind we have
seen, the judicious mixture of the line with the dot forming
a most happy foil to each other.

Wecannot help observing that this print is doubly wel-
come to us, as it shows that the arts have only beem appa*
rently on the decline since the publication, from the pictures
of Mr. West, of those fine subjects—Mark Anthony, Regu-
lus, Stralonice, and the son of Antigonus, &c. &e.. “What

. a COne
|

French National Instituté: 37

& contrast between such subjects as these and the insignifi-
cant trifles chosen by some artists trom -the different occu-
pations of children!

Historical painting, when properly executed; serves to
touse the mmd to acts of heroism or yirtue, or to instil
some great moral truth. Like music, it misses its aim if
it touch not our feelings. To be feelingly alive to whatever
is great and noble ought to be the study of every artist,
whose wish is not only himself to excel! but to improve the
public taste, as the best and only certain means of insuring
to the arts that patronage which will otherwise be expected
in vain.

LXIX. Proceedings of Learned and Economical Sotieties.
FRENCH NATIONAL INSTITUTE.

Ts following letter from C. Mecham, charged with eon-
tinuing the meridian of France to the Balearian islands,
was read in the sitting of the Institute, Monday, November
10, 1803; (
«* You know how many obstacles and how much delay
I have experienced on the continent ; as I could do nothing
else, nor better, I undertook to form the chain of triangles
on the coast of Catalonia, from the eminence of Matas on
Mount Allegre, as far as Mount Sia beyond Tortosa, which
I reached by six triangles ; the last of which only is very
large, and by a small acute triangle, that is to say, of 23
degrees. I had reverberators which I used for measuring the
angles, and with success. I did not neglect the day signals
when I was able to observe them without prolonging my
stay too much at the different stations. I am now at that
of Montserrat, which I hope soon to terminate; nothing
will then remain but thatiof Matas. My cooperators can
tell you what we had at first to suffer from the scorch-
ing heat ef the climate; how much I have been impeded
by fogs, continual rains, and torrents, the most violent
tempests and dreadful hurricanes, which assailed us almost
incessantly, and in every place, till our arrival at Montserrat.
Such a stormy state of the weather would scarcely be cre-
dible in the most intemperate climates of the earth. How~
ever, this chain of triangles: will be terminated after three
months’ labour. The distance between Matas and Mount
Sia is about 110 miles, The Pui de la Morclia and
Mola Cima, the highest of the peaks of Mount Sia, will
be the two summits of the large triangles for the islands.
Jheir distance is 85 miles ; these two points are very
Aag visible

379 French National Institute. "
visible from each other when the weather is favourable.
The height of the Morella’is 1700 feet’ above the level of
the sea; that of Mola Cima 1400; that of Silla Totellas;
in the sland of Majorea, is about 4600.

** We are now employed on this great triangle and that for
Tyica, which will be as @reat.

“* The court of Spain has given-the most positive orders
to the captain of the brig who is to convey us ‘to the Ba-
jearian islands, and to different points of the coast of Ca-
talonia, as often as may be necessary. To defend the re-
verberators and lodge the observer with his/instruments on
mountains so elevated, and during an inclement season, it
will be necessary-to ereet four huts of -w ood, or of mca
as tents would not be sufficient. i .¥

© Tn regard to the success of the triangles, it is very cer-
tain, at least inv regard’ to that which will join Majorca to
the coast of Spain. That which is to join Ivica .to the
coast of Majorea Will not be certain, tle we can find’ im
Ivica a mountain 2400 fect in height : without this’ Ivica
cannot be observed. ~T have been assured that it May be
seen from Mola Cima; but during the three weeks ‘w hich
T spent on that wretthed peak, the weather was so dismal
that T could not ascértaitt: thé truth’ of this circumstance,
whieh was’ told to me eleven years ago. I was favoured
only by one night to observe the reverberators of the moun-
tain of Leberia and the chapel of St. John. There were
two at Leberia, and three’at the chapel of St. John. They
were more than sufficient, though the distance ‘exceeds 58
miles, and though the yeast ray passed over the sea. T,
however, employed only a cirele of 18 inches with its old
sights. I can place tw jelye ¥éverberators, and even more,
on one of the summits, the most distant of those to be ob-
served, at the same tine. It was proved about eleven years
ago, that one reverberator lighted’ on the Silla de Torellas,
was observed ‘from Moutt Jouy for two hours, at. the
height of 525 feet above the lev ‘el’of the sea. This, in-
deed, was the case by using a Jarge achromatic telescope of
18 iniche®’ focus ; but the telescopes which I applied to
the circle of fig feet are as powerful as that-of three
feet, and I shall have twice as much light, and’ even
more. There will also be ayreat advantage in regard’'to the
height of the Morella and of Mount Sia, w hich is almost
triple that of Mount Jouy. ~Nothing then can retard us in
regard to this first triangle, but w aiting for a favourable mo-
ment to make our observations. As for the rest, I do not
know whether it will be possible till I traverse the moun-
tains of Ivica. But even if I find it impossible, the opera-
3 tion,

Board of Agriculiure. 373

tion, that is to say, the prolongation of the meridian to the
39th degree of latitude will not be rendered ineffectual.
ist, It will not be difficult to connect the small! island of
Cabrera to Silla de Torellas and another point of the island
of Majorca, provided we can make in that island a tew sub-
sidiary triangles, and measure a base. We shall find means
at Palma to make iron rules, and I shall carry them back to
Paris im good preservation, that I may compare them with
the platina rules used at Melun and Perpignan. 2d, Itis,
certain that Ivica may be connected with Majorca, and some
other points of the coast of the kingdom of Valencia, by the
mountains of Cape Marten and that in the environs of
Oropesa; and to unite these points to Mola Cima and Le-
beria four triangles will be, sufficient, — I shall be better able
to.form an opinion on this subject when I have visited the
mountains of Iyica, where I shall commence my operations,

.

; THE BOARD OF AGRICULTURE

ilas offered the following Premiums :
[Continued from p. 286. ]

‘Til. Cottages—To the person who shall build on his
estate the most cottages for labouring families, and assign.
to each a proper portion of land, for the support of not less
than a cow and ahog, and for a sufficient garden,—the gold
medal. Accounts of the expenses of building, land as-
signed, culture,—if any, live stock, and state of the fami-
lies, with the rent paid—verified by certificates, to be pro-
duced to the board on or before the third Tuesday in April,
1804. The same premium for 1805.

IV. Cows for Cottagers—Doubts haying been expressed
by some persons concerning the expediency of cottagers
keeping cows, except on rich soils, the board will give to the
person who shall produce the most satisfactory account, ve~
rified by experiments, of the best means of supporting cows
on poor land, ina method applicable to cottagers,—the gold
medal.— Accounts to be produced of the soil, articles culti-
vated, produce, stock kept, and every material circum-
stance—verified by certificates, on or before the first Tues-
day in May 1804. The same preniium for 1805.

V. Land for Cottagers.—The board being informed that
the labouring poor on the estates of several persons in Rut~
Jand and Lincolnshire, having land for one or two cows, and
a sufficiency of potatoes, did not apply in the late scarcity
for any parochial relief; and it appearing to be a great na-~
tional object to spread so beneficial a system, the board will
give to the person who shall explain, in the most satisfactory

Aas manner,

374 Geology.

manner, the best means of rendering this practice as generaf
through the kingdom as circumstances will admit,—the gold
medal. To be sent to the board on or before the first Tues-
day in November 1804.

[ To be continued. ]

Soo Se
LXX. Intelligence and Miscellaneous Articles,
GEOLOGY,

Mk. Esmank of Kongsberg, on his travels through Nor-
way, has lately made some very interesting researches to
determine the snow-line and line of vegetation. Of all the
mountains which he ascended the Snechutten on Dovre-
field is the highest, its altitude above the level of the sea
-being more than 8000 Rhinlandic feet: It is continually
covered with snow, and in some places, where the snow had
tumbled down, it appeared to consist of twenty-five strata,
each covered with a perceptible incrustation of ice. The
uppermost stratum, which has an undulated form, was in
the hollows.between the waves of snow weak and of an
amethyst colour, as has been observed in the, Alps. Ja
places where the rays of the sun fall in an oblique direction,
which is the case towards the. north and north-east, the
snow-line is placed at the height of 3000. feet above the
level of the sea; but towards the south and west, where the
sun is more powerful, the snow melts at the height of 7000
fect above the sea. The highest pomts which Mr. Esmark
ascended - consist of micaceous schistus, except the
mountain of T'ronfieldet between Tonstel and Foldalen, the
summit of which consists of a kind of stone hitherto un-
known, which is a “mauxture of green feldspar and schiller
spar, about 4500 fect above the level of the sea. This stone
1S SO magnetic that it changes the direction of the magnetic
needle at the distance of four feet. It is susceptible of a
fine polish ; and in regard to colour has a great similarity
to the Labrador stone. The height of the line of yegetation
in Norway is different, as well as the kinds of trees and
plants, which are more or less capable of enduring the cold.
At the height of 1000 feet several species of fruit-trees
thrive and produce abundant crops. The silver fir can bear
in Norway a greater degree of cold than the spruce fir. The
latter grows only at the height of 2000 feet; on the other
hand, the former is found at the height of 3000 feet. The
birch thrives very well to the height of 3000 feet; at a
greater altitude nothing is found but the Betula nona, toge-
ther with some willows and the juniper, which, gli

1 oes

Agriculture. 375

does not thrive at a greater height than that of 3200 feet
above the level of thesea.. Barley and oats, however, grow
at the height of from 1500 to 1800 feet, but only in vatleys.
At the height of from 1200 to 1300 feet the night frosts
aré very prejudicial to the seedy

Mr, Wolf has found near Turneau in Bohemia a pecu-
liar mass of glass produced from a blackish basaltes, which
is met with in abundance at Buchberg in Bohemia, When
‘this stone is placed in a glass furnace,, it inses in eight
hours so that boxes and other articles can be made of it,
and of any form, at pleasure. tis more.fusible than glass,
and therefore cannot be blown like glass, but cam be drawn
out into coarse threads and rods. .When coldat .is harder
than glass, and is mere difficult to be ground and to be
cut. When cast it adherés strongly to iron mouids; and
on this aceotnt moulds of brass must beemployed, It cor-
rodes the crucible also much less than glass; but this stone
‘may be used instead of manganese, as an addition to glass,
which it purifies in a similar manner,

SIR, AGRICULTURE, ,

In your 66th number of the Philosophical Magazine
there is an extract of Mr. Close’s' communication to the
Board of Agriculture, in which he says, ‘ the eighth part
of an acre of good turnips steamed, and with the liquor
mixed with oat straw cut, will keep a full grown beast in
good order six months. An acre of turnips with the first
crop of hay, will fatten two bullocks. in'the same time,
et ata : ‘a

T understand by this that one acre of steamed turnips will,
with ,oat straw nnxed in the liquor, keep. eight full grown
beasts in good order six months...

L wish to know what quantity: will make the same num-
ber of fyll grown beasts fat ?

‘There appears to me some ambiguity in the above, as also
m what followsy:namely, that four acres, with the addition
of one-fourth of an acre of turnips, will keep: only three
beasts, and fatten ¢wo bullocks. It appears to me that by
the first part, if steam was used, a great many more ought
#0°be kept... "1." Aha r
“I also'could wish to have the propér method of steaming
‘detailed, with the quantity of ‘turnips so given each anima
each day; also the quantity of oat straw; also the expense
of the steaming. pe Spree

Your) entering into this\minutely would, render an ims
portant service to the country in general, and I for one
would thank you particularly.

To Mr. Tilloch, x Yi

i -

[ W8IS4 3

INDEX tro VOL. XVIL

ae

ACID. On the gallic, 59, 61 ;
the prussic, 95; the benzoic,
151%; phosphoric, 157; flu-
oric, 350

‘Acorn. A prize question § 93

Accum on analysis of minerals,

. 364

Acrostation, 188, 191

Agriculture, 16, 178, 285, 373»

375
Aikin’sportable blast-furnace 166
Aliumen. Experiments on, 23
Almonds. Remarks on, 25, 26

Aloe, filaments of. On strength
of, 341
Ambergris, Properties and ana-
lysis of, 88,131
America, South. Geological
sketch of, 347

Ammonia. A cure for the bites
of snakes, 125, 128
Analyses of native muriate of am-
monia, 76, 77; of sassolin, 77 3
of salt of Idria, 79; of meli-
lite, 793 of muriated lead ore,

833; of the green phosphates ©

of lead, 86; of ambergris, 88,
3313 of diamond, 197; of
ruby,,201; of sapphire, 201 ;
of the emerald, 202; of the
topaz, 202 ; of hyacinth, 203;
of the beryl, 203; of catechu,
2173,0£ phosphated lead ore,
230; sulphated lead ore, 231;

white, lead ore, 2313 native.

antimony, 2 32 ; olive ore, 234;
* jron ore, 2353 copper ores,
2353 pitch stone, 236; pu-
mice stone, 237; zirconia,
* 2373 madreporite, 238; of
scorza, 2395 manganese ore,

240; sulphate of barytes, 2403
asphaltum, 242 ;_pearl-stone,
243 3 antient coins, 256; of
an antient speculum, 289; of
fossil elastic resin, 307 5 of
peat earth, 310; of human
teeth, 313; Accum on, 354
Andreoli’s aerial voyage, 188
Antimony, native. Analised, 232
Arable lands, Estimate, 183
Arts and sciences. Society of, at

Utrecht, 186
Asia. On people of, SUE
Asphaitum. Analised, 242
Astringent vegetables, Experi-

ments on, 63, 212, 293
Astronomy, LA
Atkins on hydrometers, 204,

329
Aurichalcum., On, 265

Balylonian brick, Inscription on,

explained, 250
Bank, Sir Foseph, aE
Barks. Experiments on, 63, 293
Barometer at peak of ‘Teneriffe,

¢ oe be]

Barton on bite of rattlesnake,
11128

Barytes, muriate of. + Experi-
ments on, 160; sulphate of,

analised, 240
Benzoic acid. , On, 16
Beryl. ‘On they. 314 203
Bigir’s soldier's friend, 378

' Blast-furnace. Aikin’s portable,

166
Blue. To dye, VAS
Board of Agriculiure, 285, 373
Boiler, Woolf’s, described, 40
Boilers. Own heating, Bs

Book:.

INDE X.:

Books. Notices respecting, 76,
188, 230, 284, 3075 364

Boroge. Experinieuts on, — 30
Beyle on diamond, 107
Brewer on dyeing, 149

Brewery, Meua?s, 40, 164, 275

Buck-thorn. On, cy
Burkit on fulminating’ mercury,

» 109
Cabbage. OS sr on juice
SOS 23, 29
Calico prixting. On, 323

Corbon, i's use in vegetation, 321

Catechu. Experiments on, 212
Civis, an alkaline earth, ~— 267
Close on agriculture, 173

Clouds. -On the modifications,

production, suspension, and |

destruction of, 5
Coins, antient, analized, 250
Colourless martial crystals 325
Cook, Captain, 341

Copper, an ingredient in antient
mirrors, 293
Copper ores. -Analized, 233
Cordier’s account of peak of Re
. neriffe,

Corinthian brass. On, ee 5

Cotton yarn. To dye, 149

D’ Arcet’s experiments: on dia-
monds, 197

Davy on tanning, 58, 63, 212,

293

Dayes’ conversion of Saul, 370

Delalande on stones from the
clouds, * 228
Diamond, Orienitaand Brazil-
lian, 194; where found, 195;
to select, 195 ; expetiments
on, 197 ; value of, 199 ; sizes,
ates : wa 209
Diseases, aprize question, 185 ;
on cure of, 171, 234, 360
Drilling in husbandry. On, 180
Dubin on vultures, 359
Duhamel on herring fishery, 218;
experiments on vegetation,

stg

377
Dyeing. Nankeen colour, 149

various Colours, 324

Earths. General- analyses. of,
ot) ' 364
Economical Societies, 92, 186,
283, 378

Etelcraniz’s safotyepietBn 162

Eggs. On white of, 25)
Elderberries. On, 30

Electricity of clouds, “5.3 on
Franklinian theory of, 97 a

~ prizé question, > 184
Emerald. On the, 205
Esmark, Geological remarks
by, - 374
Farina. On, 26
Fecula of plants, On, 22z
Fine Aris, 379
Fischer on red oxide of mercury,
139

Fee on meteor of Novem-
ber, 180 3. 279
Fishery, Qn thetherring, 218
Flax, On strength of, 341

Fhicric acid." Fo prepare, 357
Fossil clastic-resin. Analized, 307
Fourcroy on gluten, (Fc. exa-
mined, 27
French National Institute, 35%.
Friction. On the motion of
bodies affected by, 47, 11923
experiments on, 120
Fulminating mercury, Burkitt
on, 16¢; Hume on, a
Funerals. Indian,

Furnace. Aikin’s portable, 166

Gallic acid. in, 59, 6
Galls. Experiments on infusions
of, 67

Gelvanism, a prize question, 187

Garnerin's thirty-fifth: ‘aérial
voyage, Igt
Gelatin for detecting tannin, To
prepare, 64
Gems. Pepys ony 193
Geography, 192
Geclog 33

33, 287, 347, 374
Giese

a2

Giese on benzoic acid; 15f
Gild on Indian. ink, 210
Gipi n’s iables. On, 204, 329
Glasses Toetch on; 357
Gluten. On, 26
Grassetti’s aérial voyage, 188
Grass Jands. Fstimate, 183
Green... To dyes 324

Guersenon phosphoric acid, i57

Hausman on calico printing, 323.
Heliycr’s plate after Dayes, 370
Helmon's experiments on vege-
tation, 319
Henley's: explanation of inscrip-
_ tion on Babylonian brick,

250

Hemp. On strength of, — 341
Rlerting fishety On; 218
florse Aoving On, 180
Horses... Experiments on urine
of, 15t
Howard on the clouds, §. 5

Howard's fulminating mercury.
» Berket-on,169;, Hume on,

395
Human teeth avalized, 313
Humboldi’s. geological sketch of
. South Ameri cay 347
Hume on nitrous ether by ni-

trate of mercury, © 305.
Hyacinth. On the, 203
Hydrometers. On, 204, 329
India. On people of, It
frdian ink, On composition of,

210
Fron. -Ow alkalized oxide of,

323 5 white oxide of, 325

Klaproth Analyses by, 76, 230,
2439, 256, 267, 2893; on em-
~ ployirig platina ia porcelaig

painting, 135
Knights apparatus to prepare
fluoric. acid, 357

Kookies of India. Onthe, 15

Lagrange’ s analysis of Ege

88, 138

IN DE X.°

Lamps with two contenttic wicks
On, 305
Lavoisier on the diamond, 197
Lead ores. Ainalized, 83,86,
230, 231; found on antient
mirrérs, 2933 but not an in-
tended ingredient, | 294
Learned Societies, 94, 186, 2833
371

On the manufacture
_ 60, 63, 140, 293
Lightning. To relieve from ef-
fects of, | 306
Liitl:’s observations on barome=
ter at Teneriffe, 37;
Longevity, 192
Lunctas of Indias On the, 14

Leather.
of;

Mackrae on, the Kookies or
Lunctas, ° IL
Macquer’s experiments on dia-

monds, 197
Madreporite. Analized,.’, 238
Manganese ore. rhe ip 240

Mecbain on the meridian, 371

Medicine, pneumatic. On,.3]1y

234, 360
Meteor, singular, 191, 279
Meteorology, 59 196
Melilite. “Analized, 79

Mercury, Red oxide of, 1393
fylminating, 169, 30575, blacks

oxide of, 225
Metals. On antient. mixtures
of, 289

Meux’s brewery, 40, 104, 275

Millets a prize question, 93
Mirrors, On antient, 289.
Mitchill on cinis, 264
Mountains. Geological details

respecting, 347
Muriate, of ammonia, native

analized, 76, 773 of barytes.
Experiments on, 160

To dye, 1495

Nankeen colour.

325
Neitles, a prize question, 9%
New Zealand fax. On 34t
Nimbus clouds. Ong. ollie T°

Nitrate

INDEX.

Nitrate of silvers . Experiments
on, 158
Nitrous ether by nitrate of mer-
cury, 170, 305

Oak-bark, chemically examined,
59 ; substitutes for, 140
CEconomical-Societies, 92, 186,
283,371

Opium. A kind. of tallow in the
fecula of, 30
Optics. Improvements i in, 327
Oranges covered naturally with
wax, 30

Ornithology, 359
Oxide, white Of iton, 325
Palladium. .On, 288
Peak of Tenerife. On the, 31 5
height of, 373. Tilesius on,
286

Pearl-stone. AnsliZed, 243
Peat earth. Analized, 329

Pepys.on gems, 193 ; "jualysis of
human teeth, _ 313
Periscopic spectacles described,
“327
Phosphate of soda... Improved
method of preparing, 95
Phosphoric acid. _ On, 15%
Piston-safety, Edelcrantz’s, 162

Pitch stone. _ Analized, 236
Plague. On the, 288
Plants. On fecula of, 22

Platina applied to porcelain, 135

Pneumatic medicine.’ On, 1715.

234s 360
Polishing stuff for steel, 325.
Porcelain. ‘Yo coat with platina,

135
Portable blast-furnace. Aikin’s,
166
Potash in buck wheat, 95
Printing, calico. On, 323

Prize questions, 93, 186, 285,

373

Proust on fecula, 22
Prussian blue. Curious produc-
tion of, 326

Prussic acid, To obtain pure, 95

379

Publications. (New, 76, 188,
230, 2845 307, 364

Pumice stone. ‘Analized,’ 237
Putrefaction. On, 22

Rain. On the production of, ‘8
Ramsay on curing the bite of a

snake, 12g
Red oxide of mercury. ‘New way.
to prepare, 139
Royal Academy of Madrid, gz
Royal Lnsiitution, 285
Ruby. On the, 200

Saint Petersburgh Economical Sa-

ciety, eogs
Saffron. Experiments on, 30
Salts, sundry native. Analyzed,

: 76
Sapphire. On the, 200
Scherer on benzoic acid, LSE

Schulze's black oxide of mercury,

225

Seneca on mirrors, 2gt
Sharks, On, Sig
Shower of stones, 274
Silk. On strength of, gat
Silk, raw, is covered with wax,
3°

Silver, nitrate of. agence

on, f 158

Shins. On tanning, 60, 53, 140

293

Snake bite cured by voltile al-
kali; \ fey, .828
ieay of National Economy
Haarlem, 93
Solar eclipse, ipa
Southern’s experiments on fric-

tion, . i120
Spectacle-glasses, Improvement
in form of, 32

Speculum, antient. Analyzed, 289
Spirits. On specific gravities of,

204, 329
Stealing, a virtue in some com

munities, 15, 18
Steam-enginen. Woolf’s boiler
for), 40
Steam-valve. Woolf's, 164

Stencilling. Hints respecting, 96
Stones,

380

Stones, precious. On, 193
Stones. General analysis of, 364
Stones from the clouds, 2283 a

shower of, 271.
Sulphate of soda. New method
© of preparing, 95
Tannin. 'To ascertain the pre-

sence of, 6

Tanning. Davy on, 58,63, 212,
293 5 a memoir on, 140
Tatham on sharks, 313
Teeth, human. Analized, 313
Teneriffe. Onthe peak of, 315
height of peak, 37; Tilesius’s

© account of, 286
Tennant’s experiments on dia-
. mond, 197
Terra japonica. Experiments on,
212

Thornton on pneumatic medi-
cine, 171, 234, 360
Tilesius's account of Teneriffe,
286

Tillet’s experiments on vegeta-
tion, 319
Tim, an ingredient in antient

mirrors, 293
Titanium.» Regulus of, oO
Topaz. On the, 202
Trees, diseased. Toure, 284

Tungsten.
Urine of horses.

on,

Regulus of, 95

Experiments
1 $t

Paccinalion, a preventive of the
plague, 94; doesnot prevent
288

INDEX.

:

Fallis’s bold experiments with

the plague, ‘288
Valve-safety. K& new, 162,
~ 164

Vegetables. Experiments on, 30,
63, £46, 293; 322

Fegetation.. On, 319
Vinee on friction, 47, 1123 let-
ter to, 120
Volatile alkali, a cure for bites

of snakes, 125,128
Voyage of discovery. The Rus-
sian, 286

Vulture of Pondicherry, “°359
Walker 6n pneumatic medicine,
360

Water, ared-coloured, examined,
243

Wax, a vegetable product, not
made by bees, ‘ 29
Wollaston’s improvement in spec:
tacle glasses, 327
Woods on the Franklinian theory
Sh clectricity, 97
Wolf. Geological remarks by;

374
Woolf's boiler described, 40;

steam-valve, 164
Wright on vegetation, 319
Yarn, a prize question, 93
Yellow. To dye, 324

Zambeccari’s aévial voyage, “188
Zerconia, Analyzed, 237
Zoology, 17

END OF THE SEVENTEENTH VOLUME.

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