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THE

PHILOSOPHICAL MAGAZINE

COMPREHENDING

THE VARIOUS BRANCHES OF SCIENCE,

THE LIBERAL AND FINE ARTS,

GEOLOGY, AGRICULTURE,

MANUFACTURES AND COMMERCE.

BY ALEXANDER TILLOCH,

M.R.I.A. F.S.A. Euin. and Perth, &c.

u Nee afanrarum sane textus ideo melior quia ex se fila glgnunt, nee noster
ilior quia ex alienis libamus ut apes." Just. Lips. JMunit. Folit* lib. i, cap. i.

VOL. XXXVI.

For JULY, AUGUST, SEPTEMBER, OCTOBER, NOVEMBER,
and DECEMBER, 1810.

-> .ft- • )pv ?S°4>

LO N D O N:

PRINTED BY RICHARD TAYLOR AND CO., SHO

And sold by Richaudsons ij Cadell and Da vies; Longman, Hurst,

Rees, and Orme; Vernor, Hood, and Sharpr; Murray;

Highley; SiiF.Rwooo and Co.; Harding; London:

Constable and Co Edinburgh: Srami

ar.d Re in, and Niven, Glasgow:

& Gilbert & Hoduks, Dublin.

CONTENTS

OF THE

THIRTY-SIXTH VOLUME.

A REVIEW of the First Volume of M. J. A. Dk Lrc'«
Geological Travels in the North of Europe : with Re-
marks on some of the Geological Points which are there-
in discussed 3

'Observations on the Effects of Magnesia, in preventing
an increased Formation of Uric Acid; with some Remarks
on the Composition of the Urine « . „ 8

Remarks on Mr. Richard Walker's proposed Alterations
in the Scales of' They mo meters ... 16

The Bakerian Lecture for 1809. On some new Elec-
trochemical Researches on various Objects, particularly
the metallic Bodies, from the Alkalies, and Earths,
and on some Combinations of Hydrogen . . „ . 17, 85

Description and Analysis of the Meteoric Stone which

fell at Weston, in North America, the 4th December

1807 32

Proposal for constructing, and putting in its Place, an Iron
Tunnel under the River Thames. By Col. Lennon 34

Six Theorems, containing the chief Properties of all Regular
Douzeave Systems of Music ; with Twelve Corollaries
thence deduced, showing others of their Relations and
Thirteen Scholia, containing the Temperaments of as
many Systems, calculated thereby. With Remarks 39

Report on the Memoirs presented to ihe Society of Phar-
macy at Paris, in consequence of the Prizes offered in the
Year 1809 53

Vol.36. No. 152. Dec. 1810. a Qf

CONTENTS.

Of the Influence of Solar and Lunar Attraction on Clouds
and Vapours 58

On Crystallography. By M. Hacjy. Translated from the
last Paris Edition of his Traitc tie Minera.'ogie 64, 121

On Pendulums 81

Report of the Dublin Cow- Pock Institution, under the Pa-
tronage of His Grace the Lord Lieutenant, for 1809 96

Information, that a further Publication of the late Mr.
Smeaion's Engineery Designs and Papers is in hand. —
Copy of a List of the principal British Strata, by the late
Rev. John Michel, (of whose posthumous Papers on Geo-
logical Subjects, further Information is requested;) — ivith
some Experiments of Mr, Smeaton's on Limestones, — and
Queries respecting Mr. To field .. . . . . .. 102

An Analysis of several Varieties of British and Foreign
Salt, (Muriate of Soda,) ivith a view to explain their
Fitness for different ceconomical Purposes . . 1 06, 171

Description of a Metallic Thermometer for indicating the
higher Degrees of Temperature 119

Dr. Healy on Cupping >. .. 131

Observations on the Purity of Standard Gold . .. 132

An Estimation of the Loss of Weight which takes place in
cooking Animal Food ' . . . . 142

Letter from M. Vita lis, Professor of Chemistry at Rouen,
to M. Bouillon Lagrange, on the Amalgam of Mer-
cury and Silver, called Arbor Dianas 143

Analysis of the Atropa Belladonna . 144

Case of Hydrocele, improperly treated as Rupture . . 151

A Sketch of a History of Pus 1 61

Remarks on the Rev. C. J. Smyth's Letter on Systems of
Tuning Musical Instruments. Vol. xxxv. p. 448 . 165

An Examination of the Instructions given in an anonymous
Pamphlet published in 1809, for Tuning an Equal Tem-
pi rament of the Musical Scale 167

Analysis of the Scammonies from Aleppo and Smyrna; to

which

• *

CONTENTS.

which are subjoined some Observations on the red Colour

given to Turnsole by the Resins 181

On prime and ultimate Ratios ; with their Application to

the first Principles of the Jluxionary Calculus .. 186

Comparative Examination of the Mucous Acid formed by

the Action of the Nitric Acid: 1st, on the Gums; 2dly,

on the Sugar of Milk 191

On the Prussic and Prussous Acids J 9<5

Memoir on the Muriate of Tin 205

The Case of a Man who died in consequence of the Bile of
a Rattlesnake : with an Account of the Effects produced

by the Poison 209

On extracting liquid Sugar from Apples and Pears . . 218

On Musical Time 220

Comparative Analysis of Socotrine and Hepatic Aloes 22 1

Analysis of Aloes — . . 224

A Fatal Case of Inguinal Hernia . . . . . * . . 230

On the New Mountain Barometer 24 1

On the Land Winds of Coromandel, and their Causes 243
Hints respecting a New Theory on the Orbits of Comets 253
Description cf a Machine for securing Persons attempting
Depredations without affecting their Life or Limbs 256
An Account of a New Method of increasing the charging

Capacity of coated Electrical Jars 259

Method of constructing commodious Houses with Earthen

Walls 263

Memoir on the Alterations which the Light of the Sun un-
dergoes on passing through the Atmosphere . .. 271
On the Application of the Barometer for indicating the
Weather, and for measuring of Heights in the Atmo-
sphere 275

(Economical Process for the Preparation of the sublimed
Muriate of Mercury {Calomel): to which is subjoined an
easy Method of purifying the Calomel used in Com-
merce 281

Description of a Process by means of which we may metal-
lize Potash and Soda without the Assistance of Iron 283
Reflections on some Mineralogical Systems 286, 378, 413

On

CONTENTS.

On the Decomposition of Water by Charcoal . , . . 305
Cases 'illustrating the Effects of Oil of Turpentine in ex-
pelling the Tape-tvorm 306, 335

Description of a Camp Telegraph 321

On the Penetration of Balls into uniform resisting Sub-

stances 325

A short Account of the Improvements gradually made in
determining the Astronomic Refraction . . . . 340, 446
Some Particulars respecting the Thunder-storm at London,
and in its Vicinity, on the 31 st of August 1810 . . 349
Researches on the oxymuriaticAcid, its Nature and Combi-
nations; and on the Elements of the muriatic Acid. With
some Experiments on Sulphur and Phosphorus, made in
the Laboratory of the Royal Institution . . 352, 404

Of the Bogs in Ireland 361,437

On purifying Olive Oil for the Pivots of Chronometers 372

A further Set of Fifteen Corollaries, to the Musical

Theorems in Page 3Q, by means of which, the Tempera-'

men is of any one of the Concords being given, all the other

Temperaments mid all the Wolves can be calculated with

the greatest facility , 374

On the Barometer 376, 467

Theoretical Suggestions for the Improvement of Practical

Surgery 401

Memoir on the Diminution of the Obliquity of the Ecliptic,

as resulting from ancient Observations 424

Reply to Mr. M.'s Remarks on Mr. Smyth's Comparative

Table in vol. xxxv. p. 488 .. 435

Description of a Manometer, by means of which we may
ascertain the Changes which take place in the Elasticity
and in the Composition of a determinate Volume of Air 458

Koticcs respecting New Books 75, 39 1

Proceedings of Learned Societies 70, 152, 232, 392,469
Intelligence and Miscellaneous Articles 75, 154, 234, 308,

394, 472

List of Patents 78,159,238,318,399

Meteorological Table . . . . 80, 160. 240, 320, 400, 473

THE

THE

PHILOSOPHICAL MAGAZINE.

I. A Review of the First Volume of M. J. A. De Luc's
Geological Travels in the North of Europe : with Re-
ma? ks on some of the Geological Points which ara there-
in discussed. By a Correspondent,

To Mr. Tilloch.

Sir, As a reader of your Magazine, I have been much
gratified of late, by the extracts, remarks, and observations
which have been given by you, or communicated by your
correspondents, on subjects connected with Geology, or
Geognosy, as it seems now the fashion with many to call
it; and having just finished the perusal of a very useful
as well as entertaining work, the first volume of M. J. A.
De Luc's Geological Travels in the North of Europe, very
lately published, I beg to communicate a short account of
the same. The travels which are detailed in the present
volume, were, it seems, undertaken, for collecting an ex-
tended body of facts in refutation of certain tenets of the
late Dr. Hutton, and other geological writers, and ii> con-
firmation of the doctrines advanced by the author in his
" Elementary Treatise on Geology," lately published. The
route of our author commenced on the 23d of July 1804,
at Berlin ; he proceeded by way of Zehdenick, Furstenberg,
Strelitz, Malehin, Lague, Rostock, Wismar, Travemiinde,
Lubeck, Eutin, Kiel, and Sleswigh, to Husum ; from
whence, on the 26th of August, he embarked for Harwich,
to pursue a similar course of investigations in England, the
details of which are to form the subject of his second
volume, the publication of which will not I sincerely hope
be long delayed.

The objects of M. Dc Luc's travels here detailed, are
first stated in 27 propositions or heads : the first eleven, and
the 13th, 14th, and 13th of which, relate to the question,

Vol. 36. No. 147. July 1810. A 2 Whether

4 Review of the first Volume of M. J. A. De Luc's

Whether the present rivers and streams of water > have ex«
cavated the valleys through which they flow P a question,
which some months ago exercised the pens of two of your
correspondents, I recollect. M. De Luc seems to consi-
der it as fully proved, by the numerous facts which he
adduces in the volume before me, that rivers and brooks
have no tendency to deepen their channels, but, on the
contrary, are in every instance, with greater or less rapidity,
filling up the bottoms of the valleys with the matters
which they sweep away from the fett of the flailing cliffs
and steep banks that they undermine, in the more rapid
parts of their courses : and that the whole of trje matters
so removed by the currents of rivers, are dropped before
they reach the depths of the ocean, and arc even met by
and mingled with large quantities of pure sand, thrown up
by the tides, from such deep parts of the ocean. The
growth and operation of peat, in filling up some vales, is
exemplified by instances at pages 131, 137, 146, 24 7, 334,
344, 8cc; and in lessening, if not at length entirely filling
up and obliterating, lakes, and natural pools of water in
other instances, af pages 138, 141, 144, 145, 146, 14 7, 17 I,
1<85, 187, 190, 191, 233, 275, 281, 344, 347, &c.

The 12th, 1 6th, and 17th heads, relate to the question
Whether the holders or blocks of granite and other stones,
have emigrated on the surface of the earth P The instances
are very numerous which M. De Luc describes, through
his whole route from Berlin to Husum, of blocks of granite
and other primordial stones some of stupendous size, and of
various species, found on the tops of graveily eminences,
in the face and at the feet of gravelly cliffs by the sea side,
and on some plains, at pages 123, 127, 129,135, 137,
156, 160, 172, 173, 178, 180, 181, 194, 195, 205, 213,
220,223,224,2-26, 228, 234, 237, 238, 248, 251, 249,
255, 256, 257, 265, 272, 273, 274, 277, 278, 2/9, 285,
291,293, 301,302, 30*, 313, 323, '329, 333, 334, 344,
367, 373, 381, 384, 366, 387, 388, 8cc. These instances
are considered by our author as concurring in proving, the
impossibility of such blocks being transported along the
present or any former surface of the earth, to the places
where they are now found, and as establishing or gene-
ralizing the supposition made by Mr. Wraxall and M. Dr
Saussure in particular instances elsewhere, thai such blocks
u seemed as if they had fallen from I he sky."

I confess, however, sir, that I was somewhat disap-
pointed in finding no attempt in all these details, at pointy
jug out the exac? places of the crater- ftke orifices, whence

these

Geological Travels in the North of Europe, &c. ^ b

these primordial stones and gravel were projectedyrow he~
neath, by the explosions t*f gases and torrents of water,
that the descending masses of strata forced from the ca-
verns previously existing under them, at the time that the
dislocations of the strata and formation of mountains, hills
and valleys, by the subsidences and angular motions of the
strata, took place, according to the theory of M.De Luc: who,
at page 61 of the present volume, speaks of " certain circular
ridges of hills, which if seen from a distance by those un-
acquainted with their nature, might be taken for the bases
or circumferences of large volcanic cones, which had fallen
in ;" as existing along the course of the Rhine, covered by
such primordial blocks. I naturally expected, I say, that
many similar spot9 would have been pointed out, in the
vast tract of gravel and holders in the north of Europe^
which lie has so well described in this volume.

At pages 123, 127, 129, 277, &c. my author speaks of
flints, which had belonged to the chalk strata, as constitut-
ing part of the gravel, and considers such, as the remains
or dissolved strata of chalk ; but wherever he speaks of the
undisturbed strata, below the gravel and holders, in his
route on the south side of the Baltic, they are uniformly
said to be of sand, clay, and marie, and seem to me to
answer either to the upper part of the Paris strata, de-
scribed in your 35th volume, p. 5TJ, &c. or to strata cover-
ing them, and answering to some that cover the chalk in
England, and in the Netherlands also, according to the
opinion of your correspondent, Mr. Farey, p. 131 of your
£ame volume.

And here it may be proper to remark, that M. De Luc^
in the volume before me, p. 248 and 250, speaks, on the
authority of M. Von Willich, of similar strata of sand and
clay in the island of Rugeu in the Baltic, as being, if I
rightly understand hirp, upper strata to the cliffs of chalk,
with layers of flints and marine bodies, £00 and even 360^
feet high, in the peninsulas of Wittow apd Jasmund, in
the north part of that island : and at page 387, on the
authority of M. Harrz, he mentions, cliffs or strata of
chalk and Hints in Hedding in the island of Zeland, and
also in the promontories of Maglebye and Mandemark in
the island of Moen or Mona belonging to Denmark : all
of which seem, I think, to c^iflrm Mr. Farcy's opinion
above referred to, viz. that the ehalk strata (instead of be-
ing dissolved) still underlay all the country, across which
M. De Luc travelled : the coal and sandstone strata in the
island of Bornbolm (p. 387), prob&blv answering;, to those

A3 of

6 Review of (he first Volume ofM. J. A. De Luc's

of Leige and other continental collieries, above the chalk,
and not to any part of the British series of strata, of which
thc chalks seem nearly the uppermost.

The important question, as to whether the chalk under-
pays the south-eastern shore of the Baltic, might, I think,
receive an answer, by a minute examination of the strata
of the higher parts of the islands of Hiddensee and Um-
mantz on the west of Rugen and of Greifswaldiska Oe on
the south-east, which are said (p. 249), on the autho-
rity of M. Von Willich, to consist of calcareous strata,
which contain marine bodies, and are intermixed with*
strata of porcelain earth; since these would, seemingly,
answer to the very characteristic limestones and potter's-
clays of the basin of Paris, page 44, he, of your 35th
volume.

If Mr. Farey be right, in asserting (p. 1 3Q of the above
volume), that three miles, (or 5280 yards) in thickness of
strata are known in England, below the chalk strata, of
which I have been speaking, without the intervention of
granites of any kind, or of any of what M. De Luc calls pri-
mordial stones, in such strata (as I have understood to be
the case), does it seem probable, that the numerous ca-
vernous blasts and torrents, to which M. De Luc resorts,
for projecting his primordial blocks towards the sky, whence
they fell to the earth's surface, could have failed to have pro-
jected along with them, numerous and large specimens of
the hard British limestones, sandstones, basalts, and others ?•
but of which we read nothing in the volume of geological
travels before us, except of a few flints.

From numerous passages in this volume, and in the
Geology of M. De Luc lately published, it is plain, that at
the time of writing them, this veteran geologist was un-
acquainted with: the suggestions of Mr. Farey, in various
parts of your late volumes, as to the reversed action of
gravity, and the tidal currents, occasioned by a former and
large satellite of this planet, whereby the extensive and
vast abruptions, as Dr. William Richardson calls them*
(or the denudations as Mr. F. calls them), which the-
earth's surface in so many places has sustained, are sup-
posed to have been occasioned, as weil as the transportation
of its alluvia, and the excavation of its numerous valleys
also, if I mistake not the drift of Mr. Farey;s arguments-
with Mr. Carr, in your 33d and 34th volumes.

X very much wish, sir, that I could call the attention of

* See page 1 14 and page 25% of our 33d volume. — Editor.

M.De

Geological Travels in the North of Europe, &c. %

M. De Luc to the above subjects, and that we might hear,
what his long experience in studying nature, and in the
consideration and discussion of geological systems, would
offer, on this new hypothesis, for explaining the disrup-
tions of the strata, the transportation of alluvial matters, and
others of the vast and most mysterious operations, to which
the terraqueous globe has been subjected.

But it is perhaps high time that I should mention the
remaining subjects of the volume, which I undertook to ex-
plain, and as soon as possible conclude tins desultory letter.

The 18th, 19th, 20th, 21st, and 22d propositions, or
heads, are employed on the question, Whether the gulfs
and steep cliffs on the coasts of the ocean, were occasioned
ly its action P At page 333 it is said, " that the inden-
tations of the coasts have not been formed by the sea, but
are simply the extremities of vales, or other original in-
flections of the surface, which lay below the level of the
sea, when it came first to occupy its present bed;" and
in numerous parts of the volume before me, Facts are ad-
duced, to show that, so far from the sea being now capa-
ble of excavating gulfs, such are almost uniformly in the
process of Jill big up.

I am yet by no means satisfied, with the evidence
adduced, to decide the other part of this proposition as
M. De Luc has done, viz. that the cliffs on the sea-shore
did not originate with the action of tfce sea. A neces-'
sary consequence of numerous valleys having opened in-
to the sea below its present level, as stated above by
M. De Luc, is, that separating ridges or points of hills
equally numerous, projected or run out into the sea; and
from having often and attentively observed, the great ef-
fect which waves propelled by a high wind, oblique to the
shore in particular, have upon all projecting points, and
the powerful tendency which the beach or strand has tb
assume a regular line without sudden indentations, in al-
most all situations, I am inclined to ascribe to the waves a
power, of commencing and carrying on the ravages which
most points of hills projecting into the sea have suffered :
yet, without at all invalidating or calling in question the
Mosaic chronology, which M. De Luc is so properly in-
tent on supporting ; and I am further disposed to assume,
that so correct an observer and reasoner as M. De Luc,
could not have overlooked these circumstances, had he not
too much relied on his position, of the original marine clifls
or fecades, being the mere effect of the subsidences an&
angular motions of the strata : and not duly considering,

A 4 that

8 Observations on the Effects of

that the valley*; being of the same or usual form, which
descend into and much below the level of the sea, the se-
parating hills must have been of such usual form also; and
since, on following any mioe of hill on land, we scarcely
ever meet with a facade or perpendicular rise in or across its
height, it follows, that the numerous and almost invariably
abrupt endings of lulls at the sea, is the effect of their
abrasion, or being worn away by the waves, and not of
faults or depressions.

The 27th head dismisses the question, Whether the level
of the present sea has ever changed ? Here I cannot but
admire the address, with which M. De Luc has brought
the numerous and, indeed, invariable instances of the hori-
zontality of the new formed or modern alluvial lands, to
bear on the question, and prove, as several others of the facts
which he relates also do, that the sea has remained at its
present level, or verv near it, ever since the present race of
men, animals, or plants have existed upon the earth; and
1 may add perhaps, ever since the present race, of fish also,
have existed in its waters.

The remaining four heads, viz. the 23d, 24th, 25th, and
• 26th, relate to the question, What is the age of our present
Continents P From a chain of facts, too numerous for me
here to particularize, as they run through the whole book,
mv author endeavours to prove, and successfully, as I think,
_and have hinted already, that natural appearances and the
state of society concur in proving that, our continents can-
not at the most, be more ancient than the Scripture chrono-
logy represents them to be. i wait with some impatience
for the appearance of the 2d volume of these Travels, which
is to treat of scenes somewhat more familiar to me, and
am, sir, Yours, &c.

m July 1,1810. A. B.

II. Observations on the Effects of Magnesia, in prevent-
ing an increased Formation of Uric Acid; with some
Remarks on the Composition of the Urine. Communicated
by Mr. William T. 1>raxdk, F.R.tS. to the Society for
trie Improvement of Animal Chemistry, and by ihem to
the Royal Society*.

JVJ r. Home's inquiries into the functions ot the stomach,
and his discovery ol' liquids passing from the cardiac por-
tion, into the circulation or the Blood f, led him to con*

* From the Philosophical Traduction* for 1810, P.nrt I.

sider.

Magnesia, in Calculous Complaints, 9

skier, that the generality of calculous complaints- might
possibly be prevented, by introducing into the stomach,
such substances as are capable of preventing the formation
of uric acid, and that this mode of treatment would have
many advantages over the usual method, which consists in
attempting to dissolve the uric acid after it is formed.

He consulted Mr. Uatchett on the substance most likely
to produce this effect, and asked if magnesia, from its in-
solubility in water, was not well adapted for the purpose,
as it wuuld remain in the stomach, until it idiould combine
with any acid, or be carried along with the food towards
the pylorus.

Mr. Hatchett knew of nothing more likely to produce
the desired effect; and on putting this theory to the lest of
experiment, it was found by a very careful examination of
the urine, that in several instances where there was an in-
creased formation of uric acid, magnesia diminished it in
a much greater, degree than had been effected by the use,
and that a very liberal one, of the alkalies in the same
patient.

This circumstance led Mr. Home to wish for a more .
'complete investigation of the subject,, and he requested
me to assist him in the* prosecution of it. Since that time
many opportunities have occurred of carrying on the in-
quiry du.mg. an attendance on patients labouring under
calculous complain; s.

It is proposed to lay the results of our joint labours be-
fore this society, with a view to establish a fact of so much
imnortauce in the treatment of those diseases.

Fhe four foilowmg cases include the principal varieties
of the disorder, which have been met with, and are there-
fore selected from among many others, to prevent unne-
cessary repetitions. In each of them the urine was occa-
sionally Carefully analysed

Cask I.

A gentleman, sixty years of age, who had been in the
fcabit of induVmg in the free use of acid liquors, had re-
peatedly passed small calculi composed entirely of uric
acid; his unne .immediately after being voided, depositee!
at all th.ies a considerable quantity of that substance, in
the form of a red powder, and occasionally in large
crystals.

Nine drachms of snbearbonate of soda, dissolved in wa-
ter highly impregnated with carbonic acid, and tak< n in
<he course oi the day at three doses, appeared to have no

effect

10 Observations on the Effects of

effect whatever on the formation of uric acid; the red
sand was deposited as usual, and the small calculi continued
to form.

On account of the inefficacy of this medicine, he Was
advised to try the vegetable alkali, and three drachms of
subcarbonate of potash, dissolved in water slightly impreg-
nated with carbonic acid, were taken at similar intervals.

The deposit of uric acid in the urine was now some-
what diminished ; but during this free use of alkalies,
which, with little interruption, was persevered in for more
than a year, the small calculi still continued to be voided.

The very unusual disposition to form uric acid, and the
complete failure of the common alkaline medicines, ren-
dered this case particularly favourable for the trial of mag-
nesia, as it would afford an opportunity of comparing its
effects with those of the alkalies.

Previous to giving the magnesia, the urine was ex-
amined, to ascertain the quantity of uric acid it contained :
this being done, the patient was directed to take fifteen
grains of magnesia three times a day, in an ounce and a
half of infusion of gentian : in a week the uric acid was
found, by examining the urine, to have diminished in
quantity, and after the first three weeks it was only occa^
sionally met with.

The use of magnesia has been persevered in for eight
months, during which time no calculi have been voided,
nor has there been any material deposit in the urine.

This patient was extremely subject to heartburn, and he
likewise complained of a sense of wreight and uneasiness
about the region of the stomach, both of which symptoms
have disappeared.

Case II.

A gentleman, about 40 years of age, had during four
years occasionally voided considerable quantities of uric
acid, in the form of red sand, and had once passed a small
calculus.

His urine was generally more or less turbid, and after
taking any iking which disagreed with his stomach, even
in a sligh-. degree, the red sand often made its appearance.
He had never used the alkalies nor any other medicine, to
alleviate his disorder : he was consequently desired to take
a drachm and a half of subcarbonate of soda, dissolved in
a pin: and a half of water highly impregnated with carbonic
acid, in the course of the day, and to persevere in this
treatment for some time.

On

Magnesia in Calculous Complaints. , 1 1

On the 30th of January 1 809, he left Loudon, and re-
turned on the 6th of March following.

During his absence he had voided rather less uric acid
than usual, but had had one severe attack, in conse-
quence of which, twenty drops of the solution of pur©
potash were added to each dose of the soda water : this,
however, had not the desired effect ; for on the 10th of
March, having taken more wine than usual on the preced-
ing day, he was attacked with pain in the right kidney,
and voided with his urine a considerable quantity of uric
acid, in the form of minute red crystals. During the suc-
ceeding day, he made but little water, which deposited a
copious sediment of red sand.

For the removal of ibis symptom, he was directed to take
magnesia, in the dose of twenty grains every night and
morning, in a little water; for three successive days his
bowels were unusually relaxed, but. afterwards became re-
gular. He persevered in its use for six weeks without in-
termission : his urine was several times examined during
that period, and contained no superabundant uric acid; and
he has not had the slightest return of his complaint, al-
though he has put himself under no unusual restraint in
his mode of Jiving.

Case III.

About the middle of October 1808, a gentleman, forty-
three years of -age, after talcing violent horse exercise, was
seized with pain in the right kidney and ureter. In the
course of the night he passed a small uric calculus. For
some months previous to this attack, he bad felt occasional
pain in the kidney, but had never voided either calculi or
sand. His urine was now always turbid, and occasionally
deposited red sand.

On the 28th of October he began the use of soda water,
and for a time his urine was much improved in ap-
pearance, but the uric acid gradually returned, and at the
end of December, notwithstanding the. continued use o£
the soda water, he voided more sand, and his urine was
more loaded with mucus than it had ever been before.

In consequence of these symptoms, on the 3d of January
1809, he was directed to take twenty grains of magnesia
every night.

The urine was examined after the third dose, and the
deposit of red sand was diminished in quantity, but it
did not disappear entirely, ai:er the magnesia had been
taken for three weeks.

About.

12 Observations on the Effects of

About this time (on the 26th of January) he caught
cold, and his urine was again veryaurbid, but this was
found to be wholly the effect of mucus, and the symptom
soon left him.

On the 30ih of January he took twenty grains of mag-
nesia, and repeated it every night and motning, until the
1st of March, when his urine was perfectly healthy, and
he left it off.

On the 1st of June he again voided a little uric acid, in
the form of red crystalline sand : this attack was attended
with a slight pain along the right ureter. He returned to
the use of the magnesia, which he took twiee a day for
three weeks, in the same dose as before, and from that time
to the middle of November there had been no symptoms
of a return of tire complaint.

Case IV.

A gentleman, aged fifty- six, after recovering from a se-
vere tit of the gout, voided constantly a large quantity of
mucus in his urine, a symptom which he had never before
noticed. There was also, occasionally, abundance of red
•?and, consisting principally of uric acid, but he had never
voided a calculus.

His stomach was uncommonly weak, he was often af-
fected with heartburn, and an almost constant pain in the
neighbourhood of the right kidney. He had been in the
habit of taking tincture of bark, and other spirituous me-
dicines, from a belief that the pain in his right side arose
from gout in the stomach. ,

H« had aheady attempted to use the alkalies, which had
produced such unpleasant sensations in the stomach, that he
could not be prevailed upon to try them again in any form.

Under these circumstances, he readily acceded to a new
plan of treatment. He was directed to omit the use of
spirituous medicines, and take twenty grams of magnesia
xhree times a day in water ; but this operating too power-
fully upon the bowels, the same quantity of magnesia was
taken twice a day only, with an addition of five drops of
laudanum to each dose.

This plan was pursued without intermission for three
weeks, and he received considerable benefit, as far as con-
cerned the state of the stomach, and pain in the region of
the kidney. The urine, which was examined once a week,
was also, on the whole, improved ; but it occasionally de-
posited a very copious sediment, consisting of uric acid,
with a variable proportion of mucous secretion.

After

Magnesia in Calculous Complaints, 1 3

After a further continuance of the use of the magnesia
for three weeks, the urine was often much loaded with
uric acid and mucus; but these appearances, which before
the use of the magnesia were constant, are now only occa-
sional, so that the disposition to form a redundant quan-
tity of uric acid is much diminished: it is also deserving
of remark, i:.at there has not been the slightest symptom
of gout from the time of the last attack, winch is more
than a year back, alo'riger interval of ease than this patient
has experienced for the last six years.

He has now omitted the regular use of the magnesia;
but on perceiving any unplca-ant. sensation in the stomach,
he returns to it for a week or ten days, and then again
J eaves it off.

From the preceding cases it appears, that the effects of
magnesia taken into the stomach, are in many respects difr
ferent from those produced by the alkalies, in those patients
in whom there is a disposition to form a superabundant
quantity of uric acid.

With a view to ascertain their comparative effects on
health v urine, when taken under the same circumstances,
{he following experiments were made.

Experiment 1. On Soda.

Two drachms of subearbonate of soda were taken on
an empty stomach at nine o'clock in the morning, dis-
solved in three ounces of water, and immediately after-
wards, a large cup of warm tea.

In six minutes, about one ounce of urine was voided ;
jn twenty minutes six ounces more; and after two hours,
a similar quantity.

The first portion became very lurbid, within ten minutes
after it had been voided, and deposited a copious sediment
of the phosphates, in consequence of the action of the al-
kali upon the urine. It slightly restored the blue -colour to
litmus paper reddened with vinegar: the alkali, therefore.
was not merely in sufficient quantity to saturate the un-
combined acid in the urine, and consequently to throw
down the phosphates; but it was in excess, and the urine
was voided alkaline.

The urine voided after twenty minutes, also deposited h.
cloud of the phosphates ; but the transparency of that void-
ed two hours after the alknli had been taken, was not drs*
turbed.

Here, therefore, the effect of the alkali upon the urine,
veas at its maximum, probably in less than a quarter of an

hour

14 Observations on the Effects of

hour after it had been taken into the stomach, and in less
than two hours the whole of the alkali had passed off.

Experiment <2. On Soda, with excess of Carbonic Arid.

The same quantity of soda, dissolved in eighi ounces of
water very highly impregnated with carhoi ic .:cid, was
taken under the same circumstances as in the former ex-
periment, and the urine was voided at nearly similar in«j
tcrvals.

The separation of the phosphates was less distinct, and
less rapid. In two hours after the urine had been voided,
there was a small deposit, composed principally of phos-
phate of lime ; there was also a distinct pellicle on the sur-
face, consisting of the triple phosphate of ammonia and
magnesia. This appearance, produced by the escape of
the carbonic acid, which had before retained the ammonia-*
co-magnesian phosphate iti solution, and which now oc-
casions its deposition on the surface, is by no means un*
common, even in the urine of healthy persons : in the pre-
sent instance, it appears to prove, that carbonic acid passes
off from the stomach, by the kidneys ; for, after taking the
alkalies, in water very highly impregnated with it, the pel-
licle is uniformly produced, and is also much more abun-r
(lant and distinct than under any other circumstances

In similar experiments with potash, the results were in
all cases as similar as could be expected in researches of
this nature.

Experiment 3. On Magnesia,

Magnesia was taken under circumstances similar to those
of the soda in the former experiment: in the quantity of
half a drachm, it produced no sensible effect upon the
urine during the whole day. When taken in the dose of
a drachm at nine o'clock in the morning, the urine voided
at twelve o'clock became slightly turbid : at three o'clock
the effect of the magnesia was at its maximum, and a di-
stinct separation of the phosphate* took place, partly in
the form of a film, which when examined was found to
be the triple phosphate of ammonia and magnesia, and
partly in the state of a white powder, consisting almost
entirely of the triple phosphate and phosphate of lime.

The effect of large doses of magnesia, in producing a
white sediment in the urine, is very commonly known, and
has been erroneously attributed to the magnesia passing
off by the kidneys.

These experiments show that magnesia, even in very

large

Magnesia in Calculous Complaints, 15

large doses, neither produces so rapid an effect upon the
urine, nor so copious a separation of the phosphates, as the
alkalies ; on this its value as a remedy in calculous dis-
orders seems materially to depend.

Experiment 4. On Lime.

Two ounces of lime water, taken in the morning upon
an empty stomach, with a cup of milk and water, pro-
duced no effect whatever.

A pint of lime water, taken at four intervals of an hour
each, produced a slight deposition of the phosphates at the
end of the fifth hour. The urine voided at the third hour
was not at all affected ; at the fifth hour, the effect appeared
at its height, but was not nearly so distinct as from small
doses of soda, notwithstanding the insoluble compounds
which lime might be expected to form with the acids in
the urine.

The unpleasant taste of lime water, the quantity in which
it requires to be taken, on account of the small proportion
of the earth which is held in solution, and the uncertainty
of its effect, are circumstances which render it of little use,
excepting in some very rare cases, where it has been found
to agree particularly well with the stomach.

The effect of carbonate of lime upon the urine was much
less distinct than that of lime water: at times it produced
no effect, but when taken in very large doses, a slight de-
position of the phosphates was produced.

These experiments were repeated upon three different
individuals, and there was always an uniformity in the re-
sults.

When the medicines were taken some hours after food
being received into the stomach, their effects upon the
urine were retarded, but not prevented.

The effects of many other substances upon the urine
were examined into during this investigation ; but they
varied so much according to circumstances, that no satis-
factory results were produced.

As it is found in the foregoing experiments, that the
effects of soda on the urine are modified by the presence of
carbonic acid, the following experiment was made, to as-
certain whether any sensible effects are produced by that
acid on healthy urine.

Twelve ounces of water very highly impregnated with
carbonic acid, were taken upon an empty stomach at nine
o'clock in the morning. At ten o'clock about eight
ounces of urine were voided, which had a natural appear-

ance.

16 On Alterations in the Scales of Thermometers.

ancc, but, when compared with urine voided under common
circumstances, was found to contain a superabundant quan-
tity of carbonic acid : this gas was copiously given off
when the urine was gently heated, or when it was exposed
under the exhausted receiver of an air-pump.

In a patient who had a calculus of large dimensions
extracted from the bladder, composed entirely of the phos-
phates, and whose stomach did not Vomit of the use of
stronger acids, carbonic acid was given in water; it was
found peculiarly grateful to the stomach, and upon ex-
amining the urine during its use, the phosphates were
only voided in solution ; hut when at anv time it was left
■ oif, thev were voided in the form of white sand.

J 1 1. Remarks on Mr. Richard Walker's proposed At*
t era t ions in the ScW&s of Thermometers, in our last
dumber.

To Mr. Alloch.

Sir, 1 he reading of Mr. R. Walker's paper on thermo-
meters in your last number, induces me to trouble you, for
the purpose of pointing out to that gentleman, what I
conceive to have been the reason, why various improve-
ments and suggested reforms, in the weights, measures,
and modes of estimating quantities in this country and
others, have been neglected and most of them forgotten, viz.
their authors' having neglected to asign new and appropriate
names and characters to the new denominations or things,
which it was their object to introduce; but transferring the
old names, as foot, inch, ounce, pound, degree, &c. &c. to
things almost as new and dissimilar, as these are from each
other.

if the most precise and short compound words were
fixed on, indicative of degrees of heat and degrees of cold,
derived perhaps from the Greek or Latin, as being dead or
standard languages universally understood, to be used as new
prefixes or additions (with distinctive characters* which
could be used as abbreviations of these) to the nuinlcr of
tbermometric divisions proposed, instead of using cither the
word degrees or the character ° in present use ; I do not
dtspair of seeing Mr. W.'s scale or even scales (if each have
their own names and characters) adopted by many, since

* Perhaps the initial Greek letters of the names might answer the*e pur*
poses.

negative

On some new Electrochemical Researches, 17

negative signs would thus become unnecessary, and no con-
fusion could arise from their use; while on the other hand,
every true friend of science and accuracy, will naturally ad-
here to the divisions in use, as answering their intended ends,
although not in the best or most perfect manner; and set
their face against imperfectly contrived changes.

It would have been desirable, in the last note at bottom
of page 420, that Mr. R. Walker had pointed out a material
circumstance affecting the uses of mercurial and alcoholial
thermometers, viz. the very different periods of time ne-
cessary, for each to act in, or acquire and indicate the
temperature of any medium under experiment. — See the
Monthly Magazine, vol. xvii. p. 213.
I am ; sir,

Yours, &c.

JulyS, 1810. LONDINENSIS.

IV. The Baker ian Lecture for 1 80 9. On some new Elec-
trochemical Researches on various Objects, particularly
the metallic Bodies, from the Alkalies, and Earths,

' and on some Combinations of Hydrogen, By Hum-
phry Davf, Esq. Sec.R.S. F.R.S.E. M.R.LA*

[Continued from vol. xxxv. p. 415.]

'ill. Experiments on Nitrogen, Ammonia, and the Amal-
gam from Ammonia.

vJne of the queries that I advanced, in attempting to
reason upon the singular phsenomena produced by the
action of potassium upon ammonia, was, that nitrogen
might possibly consist of oxygen and hydrogen, or that it
might be composed from water.

1 shall have to detail in this section a great number of
laborious experiments, and minute and tedious processes,
made with the hopes of solving this problem. My results
have been for the most part negative ; but I shall venture
to state them fully, because I hope they will tend to eluci-
date some points of discussion, and may prevent other che-
mists from pursuing the same paths of inquiry, and which
at first view do not appear unpromising.

The formation of nitrogen has been often asserted to
take place in many processes, in which none of its known
combinations were concerned. 'It is not necessary to enter
into the discussion of the ideas entertained by the German

* From Philosophical Transactions for 1310, Parti.

Vol. 36. No. 147. July 1810. B chemists,

18 On some new Electrochemical Researches

chemists, on the origin of nitrogen, produced during the
passage of water through red-hot tubes, or the speculations
of Girtanner, founded on these, and other erroneous data :
the early discovery of Priestley on the passage of gase9
through red-hot tubes of earthen-ware, the accurate re-
searches of Berthollet, and the experiments of Bouillon La
Grange, have afforded a complete solution of this problem.

One of the most striking cases, in which nitrogen has
been supposed to appear without the presence of any other
matter but water, which can be conceived to supply its
elements, is in the decomposition and rccomposition of
water by electricity*. To ascertain If nitrogen could be
generated in this manner, I had an apparatus made, by
which a quantity of water could be acted upon by Voltaic
electricity, so as to produce oxygen and hydrogen with
great rapidity, and ill which these gase9 could be detonated,
without the exposure of the water to the atmosphere; so
that this fluid was in contact with platina, mercury, and
glass only ; and the wires for completing the Voltaic and
common electrical circuit were hermetically inserted into
rhe tube. 500 double plates of the Voltaic combination
were used, in such activity that about the eighth of a cu-
bical inch of the mixed gases, upon an average, was pro-
duced from 20 to 30 times in everv day. The water used
in this experiment was about a half a cubic inch ; it had
been carefully purged of air by the air-pump and by boil-
ing, and had been introduced into the rube, and secured
from the influence of the atmosphere whilst warm. After
the fir^t detonation of the oxygen and hydrogen, which
together equalled about the eighth of a cubical inch, there
was a residuum of about 1'(T of the volume of the gases;
after every detonation this residuum was found to increase,
and when about 50 detonations had been made, it equalled
rather more than { of the volume of the water, i. e. {■ of a
cubical inch. It was examined by the test of nitrous gas;
it contained no oxygen ; six measures mixed with three
measures of oxygen diminished to five; so that it consisted
of 2*6 of hydrogen, and 3*4 of a gas having the characters
of nitrogen.

This experiment seemed in favour of the idea of the
production of nitrogen from pure water in these electrical
processes ; but though the platina wires were hermetically
sealed into the tube, it occurred to me as possible that at

* See Dr. Pearson V. elaborate experiments, on the decomposition of water
by electrical "explosions. Nicholson's Journal, 4to, vol. i. page 301.

the

on various Objects, 1$

the moment of the explosion by the electrical discharge,
the sudden expansions and contractions might occasion
some momentary communication with the external air
through the aperture ; and I resolved to make the experi-
ments in a method by which the atmosphere was entirely
excluded. This was easily done by plunging the whole of
the apparatus, except the upper parts of the communicating
wires, under oil, and carrying on the process as before. In
this experiment the residuum did not seem to increase
quite so fast as in the former one. It was carried on for
nearly two months. After 310 explosions, the permanent
gas equalled -£fo of a cubical inch. It was carefully exa-
mined : six measures of it, detonated with three measures
of oxygen, diminished to rather less than one measure ; — a
result which seems to show, that nitrogen is not formed
during the electrical decomposition and recomposition of
water, and that the residual gas is hydrogen. That the
hydrogen is in excess, may be easily referred to a slight
oxidation of the platina.

The refined experiments of Mr. Cavendish on the defla-
gration of mixtures of oxygen, hydrogen, and nitrogen,
lead directly to the conclusion, that the nitrous acid some-
times generated in experiments on the production of water,
owes its origin to nitrogen, mixed with the oxygen and
hydrogen, and is never produced from those two gases
alone. In the Bakerian lecture for 1806, I have stated
several facts, which seem to show that the nitrous acid,
which appears in many processes of the Voltaic electrization
of water, cannot be formed, unless nitrogen be present.

Though in these experiments I endeavoured to guard
with great care against all causes of mistake, and though I
do not well see how I could fall into an error, yet I find
that the assertion, that both acids and alkalies may be pro-
duced from pure water, has again been repeated*. The
energy with which the large Voltaic apparatus, recently
constructed in the Royal Institution, acts upon water, en-
abled me to put this question to a more decided test than
was before in my power. J had formerly found in an ex-
periment, in which pure water was electrified in two gold
cones in hydrogen gas, that no nitrous acid nor alkali was
formed. It might be said, that in this case the presence of
hydrogen dissolved in the water, would prevent nitrous
acid from appearing; I therefore made two series of ex-
periments, one in a jar filled with oxygen gas, and the

* Nicholson's Journal, Augutt 1809, p. 258.

B 2 other

to On some new Electrochemical Researches

other in an apparatus in which glass, water, mercury, and
mires of platina only, were present.

In the first series 1000 double plates were used, the two
cones were of platina, and contained about -pV of a cubical inch
each, and filaments of asbestos were employed, to connect
them together. In these trials, when the batteries were in
full action, the heat was so great, and the gases were dis-
engaged with so much rapidity, that more than half the
water was lost in the course of a few minutes. By using
a weaker charge, the process was carried on for some hours,
and in some cases for from two to three days. In no in-
stance, in which slowly distilled water was employed, and
in which the receiver was filled with pure oxygen from
oxymuriate of potash, was any acid or alkali exhibited in
the cones ; even when nitrogen was present, the indications
of the production of acid and alkaline matter were very-
feeble ; though, if the asbestus was touched with unwashed
hands, or the smallest particle of neutro-saline matter in-
troduced, there was an immediate separation of acid and
alkali, at the points of contact of the asbestus with the
platina, which could be made evident by the usual tests.

In the second series of experiments, the oxygen and hy-
drogen produced from the water were collected under mer-
cury, and the two portions of water communicated directly
with each other. In several trials made in this way, with
a combination of 500 plates, and continued for some days,
it was always found that fixed alkali separated in the glass
negatively electrified ; and a minute quantity of acid, which
could barelv be made evident by litmus, in the glass posi-
tively electrified. This acid rendered cloudy nitrate of sil-
ver* Whether its presence was owing to impurities which
might rise in distillation with the mercury, or to muriatic
acid existing in the glaste, I cannot say ; but as common
salt perfectly dry is not decomposed by silex, it seems very
likely that muriatic acid in its arid state may exist in com-
bination in glass.

I tried several experiments on the ignition and fusion of
platina by Voltaic electricity, in mixtures of the vapour of
water and oxygen gas. I thought it possible, if water could
be combined with more oayge7i9 that this heat, the most
intense we are acquainted with, might produce the effect.
When the oxygen was mixed with nitrogen, nitrous acid
was formed ; but when it consisted of the last portions
from oxymuriate of potash, there was not the slightest in-
dication of such a result.

Water in vapour was passed through oxide of man-
ganese,

on various Objects, 21

ganesc, made red hot in a glazed porcelain tube, the bore of
which was nearly an inch in diameter; in this case a so-
lution of nitrous acid, sufficiently strong to be disagreeably
sour to the taste, and which readily dissolved copper, was
formed.

This experiment was repeated several times, and, when
the diameter of the tube was large, with precisely the same
results. When red oxide of lead was used instead of oxide
of manganese, no acid was however generated; but upon
this sub nance a single trial only was made, and that in a
small tube, so that no conclusion can with propriety be
drawn from this failure.

1 stated in the last Bakerian lecture, that in attempting
to produce ammonia from a mixture of charcoal and pearl-
ash, that had been ignited by the action of water, in the
manner stated by Dr. Woodhouse, 1 tailed in the trial in
which the mixture was cooled in contact with hvdrogen.
I have since made a number of similar experiments. In
general, when the mixture had not been exposed to air,
there was little or no indication of the production of the
volatile alkali ; but the result was not so constant as to be
entirely satisfactory; and the same circumstances could
not be uniformly obtained in this simple form of the ex-
periment. I had an apparatus made, in which the pheno-
mena of the process could be more rigorously examined.
Pure potash and charcoal, in the proportion of one to four
in weight, were ignited in the middle of a tube of iron,
furnished with a system of stopcocks, and connected with
a pneumatic apparatus, in such a manner that the mixture
could be cooled in contact with the gas produced during
the operation ; and that water exhausted of air could be
made to act upon the cooled mixture, and afterwards di-
stilled from it : figures of this apparatus, and an account
of the manner in which it was used, are annexed to this
paper. In this place I shall state merely the general re-
sults of the operations, which were carried on for nearly
two months, a variety of precautions being used to prevent
the interference of nitrogen from the atmosphere.

In all cases in which the water was brought in contact
with the mixture of charcoal and potash, when it was per-
fectly cool, and afterwards distilled from it by a low heat,
it was found to hold in solution small quantities of am-
monia ; when the operation was repeated upon the same
mixture, ignited a second time, the proportion diminished ;
in a third operation it was sensible, but in the fourth barely
perceptible. The same mixture, however, by the addition

B3 of

22 On some new Electrochemical Researches

of a new quantity of potash, again gained the power of
producing ammonia in two or three successive operations ;
and when any mixture had ceased to give ammonia, the
power was not restored by cooling it in contact with air.

Ammonia was produced in a case in which more than
200 cubical inches of gas had passed over from the action
of water upon a mixture, and when the last portions only
were preserved in contact with it during the cooling. In
a comparative trial it was however found, that considerably
more ammonia was produced, when a mixture was cooled
in contact with the atmosphere, than when it was cooled
in contact with the gas developed in the operation.

I shall not attempt to draw any conclusions from these
processes. It would appear from some experiments of
M. Berthoilet, that nitrogen adheres very strongly to char-
coal*. The circumstances that the ammonia ceases to be
produced after a certain number of operations, and that the
quantity is much greater when free nitrogen is present,
are perhaps against the idea that nitrogen is composed in
the process. But till the weights of the substances conr
cerned and produced in these operations are compared, no,
correct decision on the question can be made.

The experiments of Dr. Priestley upon the production of
nitrogen, during the freezing of water, induced that philo-
sopher to conceive, either that water was capable of being
converted into nitrogen, or that it contained much more
nitrogen than is usually suspected.

I have made some repetitions of his processes. A quan-
tity of water, (about a cubical inch and a quarter,) that
had been produced from snow, boiled and inverted over
mercury whilst hot, was converted into ice, and thawed in
16 successive operations ; gas was produced, hut after the
first three or four times of freezing there was no notable
increase of the volume. At the end of the experiment,
about -5^5- of a cubical inch was obtained, which proved tcj
be common air.

About four cubical inches of water from melted snow
were converted into ice and thawed, four successive times,
in a conical vessel of wrought iron. At the end of the
fourth process, the volume of gas equalled about -^l- of the
volume of the water. It proved to contain about T}^ oxy-
gen, -jSjj- hydrogen, and T^ nitrogen.

Mr. Kirwan observed the fact, that when nitrous gas
and sulphuretted hydrogen are kept in contact for some

Mem. tf Arcueil, torn. ii. page 485.

time^

on various Oljects. 23

time, there is a great diminution of volume, and that the
nitrous gas becomes converted into nitrous oxide, and that
suIptuiMS deposited which has an ammoniacal ,-mcll. I
repeated this experiment several times in 1800 with similar
results, and I found, that the diminution of the yolume of
the gases when they were mixed in equal proportions., was
to rather less than j , which seemed to be nitrous oxide.

In reasoning upon this phenomenon, I saw grounds for
a minute investigation of it. Sulphuretted hydrogen, as
appears from experiments which I have stated on a former
occasion, and from some that I shall detail towards the
conclusion of this lecture, contains a volume of hydrogen
equal to its own. But one of hydrogen demands half
its volume of oxygen to convert it into water, and nitrous
gas consists of about half a part in volume of oxygen ; so
ihar, supposing the whole of the hydrogen employed in ab-
sorbing oxygen from nitrous gas, nitrogen alone ought to
he formed, and not nitrous oxide. Or, if the whole of the
gas is nitrous oxide, this should contain all the nitrogen of
the nitrous gas, leaving none to be supplied to the am-
monia. I mixed together five cubical inches of nitrous
fas, and five of sulphuretted hydrogen over mercury, the
arometer being at 2Q-5in\ thermometer at .51° Fahrenheit;
twelve hours had elapsed before any change was perceived;
there was then a whitish precipitate formed, and a deep
yellow liquid becran to appear in drops, on the inside of the
jar, and the volume of the gases quicklv diminished;
after two days the diminution ceased, and the volume be^
came stationary; the barometer was at 30,45:n#, and ther-r
momcter 52° Fahrenheit ; when it equalled 2*3. The gas
proved to be about | nitrous oxide, and the remaining
fourth was inflammable. An experiment was made ex-
pressly to determine the nature of the deep yellow liquid in
the jar. It proved to be of the same kind as Boyle's
fuming liquor, the hydrosulphuret of ammonia, but with
sulphur in great excess.

In this experiment there was evidently no formation
of nitrogen, and these complicated changes ended in the
production of two new compounds; nitrogen, hydrogen;
oxygen and sulphur combining to form one; and a part of
the nitrogen and oxygen, becoming more condensed, to
form another.

Having stated the results of the investigation on the pro-
duction of nitrous acid and of ammonia, in various pro-
ceases of chemistry, I shall notice some attempts that I
made to decompound nitrogen, by agents which I con-

B 4 ceive4

24 On some new Electrochemical Researches

ceived might act at the same time on oxygen, and on the'
basis of nitrogen. Potassium, as I have before stated,
sublimes in nitrogen, without altering it, or being itself
changed : but I thought it possible, that the case might be
different, if this powerful agent were made to act upon ni-
ti\>gcn, assisted by the intense heat and decomposing ener-
gy of Voltaic electricity.

I had an apparatus made, by which the Voltaic circuit
could be completed in nitrogen gas, confined by mercury,
by means of potassium and platina. The potassium, in the
quantity of about two or three grains, was placed in a cup
of platina, and by contact with a wire of platina it could
be fused and sublimed in the gas. The quantity of nitro-
gen was usually about a cubical inch. The battery em-
ployed was always in full action for these experiments, and
consisted of one thousand double plates. The phaenomena
were very brilliant : as soon as the contact with the potas-
sium was made there was always a bright light, so intense
as to be painful to the eye ; the platina became white hot ;
the potassium rose in vapour; and by increasing the di-
stance of the cup from the wire, the electricity passed
through the vapour of the potassium, producing a most
brilliant flaine, of from half an inch to an inch and a
quarter in length; and the vapour seemed to combine with
the platina, which was thrown off in small globules in a
State of fusion, producing an appearance similar to that
produced by the combustion of iron in oxygen gas.

In all trials of this kind, hydrogen was produced"; and
in some of them there was a loss of nitrogen. This at first
seemed* to lead to the inference that nitrogen is decom-
pounded in the process ; but I found that, in proportion
as the potassium was introduced more free from a crust of
potash, which would furnish water and consequently hy-
drogen in the experiment, so in proportion was there less
of this gas evolved ; and in a case in which the greatest
precautions were taken, the quantity did not equal | of
the volume of gas, and there was no sensible quantity of
nitrogen lost.

The largest proportion of nitrogen which disappeared in
any experiment, was T\ of the quantity used; but in this
case the crust of potash was considerable, 3nd a volume of
hydrogen, nearly equal to J of the nitrogen, was produced.
It cannot be said that the nitrogen is not decomposed in
this operation ; but it seems much more likely that the
slight loss is owing to its combination with nascent hy-
drogen, and its being separated with the potassium in the

form

on various Objects* 25

form of the gray pyrophoric sublimate, which T have found
is always produced when potassium is electrized and con-
verted into vapour in ammonia.

The phosphuiet of lime in its common state is a con-
ductor of' electricity; and when it was made the medium
of communication between the wires of the great battery,
it burnt with a most intense light. It was ignited to
whiteness in nitrogen gas ; a little phosphuretted hydrogen
was given oft from it, but t*he nitrogen was not altered;
the apparatus was similar to that used for the potassium.

As almost all compounds known to contain hydrogen
are readily decomposed by oxvmuriatic acid gas, a mixture
of nitrogen rind oxvmuriatic acid gas was passed through
a porcelain tube heated to whiteness ; the products were
received in a pneumatic apparatus over water, there was a
small loss of nitrogen ; but the greatest part came over
densely clouded ; and as nitromuriatie acid was found dis-
solved in the water, no conclusions concerning the decom-
position of nitrogen can be drawn from the process.

The general tenant of these inquiries cannot be consi-
dered as strengthening in any considerable degree, the
suspicion which T formed of the decomposition of nitro-
gen, by the distillation oi the olive-colonrcd substance from
potassium and ammonia, in tubes of iron. *

In reasoning closely upon the phaenomena in this opera-
tion, it appears to me indeed possible to account for the
loss of nitrogen, without assuming that it has been con-
verted into new matter. Though the iron tubes which J,
used were carefullv cleaned ; yet still it was not unlikely
that a small quantity of oxide might adhere to the welded
parts; the oxygen of which, in the beginning of the pro-
cess of distillation, might form water with hvdrogen, given
off from the fusible substance ; which being condensed in
the upper part of the tube, would be again brought into
action towards the close of the operation, occasioning the
formation, and possibly the absorption of some ammonia,
and consequently a loss of nitrogen, and the production of
an increased proportion of hydrogen. 1 have made one
experiment, with the hopes of deciding this question, in
an iron tube used immediately after the whole internal
surface had been cleaned by the borer; six grains of potas-
sium were used in a tray of iron, nearly thirteen cubical
inches of ammonia were absorbed, and about six of hydro-
gen produced. Thirteen cubical inches of gas were evolved
ia the first operation ; which consisted of nearly one cubi-
cal

26 On some new Electrochemical Researches

cal inch of ammonia, four of nitrogen, and eight of hy-
drogen. The portion of gas given off in the second ope-
ration equalled 3 '6 cubical inches; which consisted of
2*5 hydrogen, and ri nitrogen. The potassium produced
in the ^operation was sufficient to generate 3*1 cubical
inches of hydrogen.

As the iron in these experiments had been heated to in-
tense whiteness, and must have been very soft ; it was not
impossible, considering the recent experiments of M. Has-
senfratz *, that the loss of so large a portion of potassium
might depend upon an intimate union of that body with
iron, and its penetration into the substance of the tube.
This idea is countenanced by another experiment of the
same kind, in which the heat was raised to whiteness, and
the barrel cut into pieces when cool :* on examining the
lower part of it, I found in it a very thin film of potash ;
but which, I conceive, could scarcely equal a grain in
weight. The pieces of the barrel were introduced under a
jar inverted in water ; at the end of two days nearly 2-3
cubical inches of hydrogen were found to be generated.

In the experiments detailed in page 53. of the last volume
of the Transactions f, a loss of nitrogen, and a production of
hydrogen, was perceived in a case in which the residuum
from a portion of fusible substance, which had been ex-
posed to a low red heat, was distilled in a tube of platina ;
but in this case the residuum had been covered by naphtha,
and it is possible that ammonia might have been regene-
rated by hydrogen from the uaphtha, and absorbed by that
fluid ; and a part of the hydrogen might likewise proceed
from the decomposition of the naphtha: and in several
experiments in which I have burnt the entire fusible sub-
stance, I have found no loss of nitrogen.

Even the considerable excess of hydrogen, and deficiencv
of nitrogen, in the processes in which the fusible substance
is distilled with a new quantity of potassium, page 451 J, it
is possible to refer to the larger quantity of moisture, which
must be absorbed by ,the fusible substance from the air,
during the time occupied in attaching the potassium to the
tray, and likewise from the moisture adhering to the crust
of potash, which always forms upon the potassium, during
its exposure to air.

These objections are the strongest that occur to me,

Phil. Mag. vol xrxiii. page 8. \ Ibid. vol. xxxW. p?gc 3S9.

against.

ft

on various Ohjects, 97

against the mode of explaining the phenomena by suppos-
ing nitrogen decomposed in the operation ; but they cannot
be considered as decisive on this complicated and obscure
•question, and the opposite view may be easily defended.

Though I have already laid before the Society a (lumber
of experiments upon the decomposition of ammonia, yet I
shall not hesitate to detail some further operations which
have been conducted according to new views of the subject.

I concluded from the loss of weight taking place in the
electrical analysis of ammonia, that water or oxygen was
probably separated in this operation; but I was aware that
objections might be made to this mode of accounting for
the phenomenon.

The experiment of producing an amalgam from ammo-
nia, which regenerated volatile alkali, apparently by oxida-
tion, confirmed the notion of the existence of oxygen in
•this substance; at the same time it led to the suspicion, that
of the two gases separated by electricity, one, or perhaps
both, might contain metallic matter united to oxygen : and
the results of the distillation, of the fusible substance,
from potassium and ammonia, notwithstanding the ob-
jections I have made, can perhaps be explained on such a
supposition.

Thave made a number of experiments upon the decom-
position of considerable quantities of ammonia, both by
Voltaic and common electricity; and T have used an ap-
paratus (of which a figure is attached to this paper) in
which nothing was present but the gas, the metals for
conveying the electricity, and glass. The ammonia was
introduced by a stopcock which was cleared of common
air, into a globe that was exhausted, after bcins; filled two
or three times with ammonia : the gas that was used was
absolutely pure, the decomposition was performed without
any possibility of change in the volume of the elastic mat-
ter, and the apparatus was such, that the gas could be ex-
posed to a freezing mixture, and the whole weighed before
and after the experiment.

The object in keeping the volume the same during the
decomposition, was to produce the condensation of any
aqueous vapour, which if formed in small quantity in the
operation, (on the theory of the mechanical diffusion of
vapour in gases,) might in the common case of decompo-
sition, under the usual pressure, be in quantity nearly twice
as much in the hydrogen and nitrogen, as in the ammonia.

In all instances it was found, that there was no loss of
weight of the apparatus, nor was there any deposition of

2£ On some new Eltctrochemkal Researches

moisture, during or after the electrization ; but the wires .
were unifoimly tarnished ; and in an experiment in which
surfaces of brass were used, a small quantity of olive-co-
loured matter formed on the metal ; but though in this case
nearly eight cubical inches of ammonia were decomposed,
the weight of the oxidated matter was so minute as to he
scarcely sensible. By the use of a freezing mixture of
muriate of Jime and ice, which diminished the temperature
lo —15°, there was a very feeble indication given of the
addition of hydrometrical moisture.

In these experiments the increase of the gas was uni-
formly (within a range of five parts) from 100 to 185,
and the hydrogen was to the nitrogen in the average pro-
portions of from 7374 to 2726; the proper corrections
being made, and the precautions before referred to being
taken * .

Assuming the common estimations of the specific gra-
vity of ammonia, of hydrogen, and nitrogen, the con-
clusions which I have advanced in the Bakerian lecture for
1807 would be supported by these new experiments; but
as the moisture and oxygen visibly separated cannot be
conceived to be as much as -fa or TV of the weight of the
ammonia, I resolved to investigate, more precisely than I
had reason to think had been hitherto done, the specific
gravities of the gases concerned in their dry state ; and
the very delicate balance belonging to the Royal Institution
placed the means of doing this in my power.

Nitrogen, hydrogen, and ammonia, were dried by a long

* Philosophical Transactions 1 809, page 459. M. Berthollet, Jim. in the
second volume of the Memoirs of Arcueil, has given a paper on the Uccom-
position of ammonia, and he enters into an examination of my idea of the
oxygen separated in the electrical decomposition of ammonia, which he
supposes I rate at 20 per cent, and at the same time he confutes some ex-
periments which he is pleased to attribute to me, of the combustion of
charcoal and iron in ammonia. His argumenis and his facts upon these
points appear to me perfectly conclusive; but as I never formed such an
opinion, as that 20 of oxygen were separated in the experiment, and never
imagined such results as the combustion of iron and charcoal in ammonia,
and never published any thing which could receive such an interpretation,
I shall not enter into any criticism on this part of his paper. The experi-
ments of this ingenious chemist on the direct decomposition of ammonia
seem to have been conducted with much care, except as to the circumstauce
of his not boiling the quicksilver; which I conceive has occasioned him to
over-rate the increase of volume. At *il events a loss of weight is more
to be expected than an increase of weight, in all very refined experiments of
this kind. It is possible ihat the volume may be exactly doubled, and that
the nitrogen may be to the hydrogen as one to three; but neither the
numerous experiments of IV. Henry, nor those that I have tried, establish
ihis; it is one of the hypothetical inferences that may be made, but it can-
not be regarded as an absolute fact.

continued

on various Objects, -9

continued exposure to potash, and were very carefully
weighed. Their relative specific gravities proved to be at
3()-bm' barometer, 51° Fahrenheit's thermometer.

For nitrogen, the 100 cubical inches 29*8 grains.

For hydrogen, ditto 2*27

For ammonia 18*4

Now, if these data be calculated upon, it will be found,
that in the decomposition of 100 of ammonia, taking even
the largest proportions of gases evolved, there is a loss
°f tV*5 aiul " lne smallest proportion be taken, the loss
will be nearly T\.

These results and calculations agree with those that I
have before given, and with those of Dr. Henry.

The lately discovered facts in chemistry, concerning the
important modifications which bodies may undergo by very
slight additions or subtractions of new matter, ought to
render us cautious in deciding upon the nature of the pro-
cess of the electrical decomposition of ammonia.

It is possible, that the minute quantity of oxygen which
appears to be separated is not accidental, but a result of
the decomposition ; and if hydrogen and nitrogen be both
oxides of the same basis, the possibility of the production
of different proportions of water, in different operations,
might account for the variations observed in some cases In
their relative proportions ; but on the whole, the idea that
ammonia is decomposed into hydrogen and nitrogen alone,
by electricity, and that the loss of weight is no more than
is to be expected in processes of so delicate a kind, is, in
my opinion, the most defensible view of the subject.

But if ammonia be capable of decomposition into nitro-
gen and hydrogen, what, it will be asked, is the nature of
the matter existing in the amalgam of ammonia ? what is
the metallic basis of the volatile alkali? These are ques-
tions intimately connected with the whole of the arrange-
ments of chemistry; and they are questions, which, as our
instruments of experiment now exist, it will not, I fear, be
easy to solve.

I have stated in my former communication on the amal-
gam from ammonia, that, under all the common circum-
stances of its production, it seems to preserve a quantity of
water adhering to it, which may be conceived to be suffi-
cient to oxidate the metal, and to reproduce the ammonia.

* 100 of ammonia at the rale of 185, will give 130*9 of hydrogen, weigh-
ing 3-1 grains, and 481 of nitrogen, weighing 14-33 grains; but 184— 17-4
= 1, and at the rate of 180, 133 of hydrogen weighing 3 01 and 47 of nitro-
gen weighing 14, and 18-4—17 = 1-4'.

I have

30 On some new Electrochemical Researches

I have tried various devices wilh the hopes of being able
to form it from ammonia in a dry state, but without suc-
cess. Neither the amalgams of potassium, sodium, or
barium, produce it in ammooiacal gas; and when they are
heated with muriate of ammonia, unless the salt is moist,
there is no metallization of the alkali.

I have acted upon ammonia by different, metallic amal-
gams negatively electrified, such as the amalgams of gold
and silver, the amalgam of zinc, and the liquid amalgam
of bismuth and lead; but in all these cases the effect was
less distinct than when pure mercury was used.

By exposing the mercury to a cold of —20° Fahrenheit,
in a close tube, I have succeeded in obtaining an amalgam
in a much more solid state ; yet this decomposed nearly as>
rapidly as the common amalgam, but it gave off much more
gaseous matter; and in one instance I obtained a quantity
which was nearly equal to six times its volume.

The amalgam which I have reason to believe can be made
most free from adhering moisture, is that of potassium,
mercury, and ammonium in a solid state. This, as I have
mentioned in my former communication, decomposes very
slowly, even in contact with water, and, when it has been
carefully wiped with bibulous paper, bears a considerable
heat without alteration. I have lately made several new
attempts to distil the ammonium from it, but without suc-
cess. When it is strongly heated in a green glass tube filled
with hydrogen gas, there is always a partial regeneration of
ammonia; but with this ammonia there is from -/V to t^
of hydrogen produced.

As it does not seem possible to obtain an amalgam in an
uniform state, as to adhering moisture, it is not easy to
say what would be the exact ratio between the hydrogen
and ammonia produced, if no more water was present
than would be decomposed in oxidating the basis. But in
the most refined experiments which I have been able to
make, this ratio is that of one to two; and in no instance
in which proper precautions are taken, is it less ; but un-
der common circumstances often more. If this result is>
taken as accurate, then it would follow, that ammonia
(supposing it to be an oxide) must contain about 48 per
cent, of oxygen, which, as will be hereafter seen, will agree
■with the relations of the attractions of this alkali for acids,
to those of other salifiable bases'*.

If

* Even in common air, the amalgam evolves hydrogen and ammonia,
keaxly in these proportions, and in one experiment which I lately tried,

there

on various Objects. 3 1

IF hydrogen be supposed to be a simple body, and nitro*
gen an oxide, then, on the hypothesis above stated, nitrogen
would consist of nearly 48 of oxygen, and 34 of basis ; but
if the opinion be adopted, that hydrogen and nitrogen are
both oxides of the same metal, then the quantity of oxygen
in nitrogen must be supposed less.

These views are the most obvious that can be formed,
on the antiphlogistic hypothesis, of the nature of metallic
substances ; but if the facts concerning ammonia were to
be reasoned upon, independently of the other general phe-
nomena of chemical science, they perhaps might be more
easily explained on the notion of nitrogen being a basis,
which became alkaline by combining with one portion of
hydrogen, and metallic, by combining with a greater pro-
portion.

The solution of the question concerning the quantity of
matter added to the mercury in the formation of the amal-
gam, depends upon this discussion 5 for, if the phlogistic
view of the subject be adopted, the amalgam must be sup-
posed to contain nearly twice as much matter as it is con-
ceived to contain on the hypothesis of deoxygenation. In
the last Bakerian lecture, I have rated the proportion at
ttotto > Dut this is the least quantity that can be assumed,,
the mercury bein«; supposed to give off only one and a half
its volume of ammonia. If the proportion stated in page
56 [page 30 preceding] be taken as the basis of calculation,
which is the maximum that I have obtained, the amalgam
would contain about -f-g-Vo of new matter, on the antiphlo-
gistic view, and about -g-^- on the phlogistic view.

I shall have, occasion to recur to, and to discuss more
fully, these ideas, and I shall conclude this section by
stating, that though the researches on the decomposition
and composition of nitrogen, which have occupied so large
a space in the foregoing pages, have been negative, as to
the primary object, yet they may not possibly be devoid of
useful applications. It does not seem improbable, that
the passage of steam over hot manganese may be applied

there seemed to be no absorption of oxygen from the atmosphere. This
circumstance appears to me in favour of the antiphlogistic view of the me-
tallization of the volatile alkali ; for it the hydrogen be supposed to bf
given off from the mercury, and not to arise from the decomposition of water
Sphering to the amalgam,' it might be conceived, that being in the nascent
state, it would rapidly absorb oxygen. In my first experiments upon the
amalgam, finding that common air, to which it hud been exposed, gave less
diminution with nitrous gas than before, I concluded naturally, that oxy-
gen had been absorbed; but this difference might have arisen, partly at
!e^-t, from the mixture of hydrogen. Whether in any ca*e the amalgam
absorbs osv£cn g?»<. is a question for further foyesrigasfoih

00

32 Description and Analysis

to the manufacture of nitrous acid. And there is reason
to believe that the ignition of charcoal and potash, and
their exposure to water, may be advantageously applied to>-
thc production of volatile alkali, in countries where fuel is
cheap.

[To be continued.]

V. Description and Analysis of the Meteoric Stone which
Jell at IVestony in North America, the 4th December
1807. By David Bailie Warden, Esq, Consul-,
general of the United States at Paris *.

DESCRIPTION.

JL his aerolite presents, in general, the same characters as
those hitherto examined. It is enveloped with a thin,
black, and uneven crust. The mass is principally com*
posed of a granular substance, which breaks easily; it has
an earthy appearance and a gray cinereous colour, which,
in certain parts, passes to a whitish gray.

Those portions which possess this last tint, and which are
as if glued in the mass, have a round form, so that they
are distinguished by circular or oval spots which interrupt
the general colour. Its specific gravity is about 3*3 ; the
sharp parts cut glass.

In observing the fractured parts of the stone, we there
perceive : 1°. Particular globules which are easily detached;
little cells in which they are placed, and of which the sub-
stance is like that of the stone itself, except that its grain
is more compact, and its fracture smoother.

In exposing it to a strong light, we see traces of a la-
mellar tissue : 2°. grains of metallic iron, which, by polish,
assume a whiteness, yield to the hammer, and attract very
sensibly the magnetic needle : 3°. grains of oxided iron of
the colour of rust : 4°. metallic particles extremely small,
of a silver white colour, which seem to be of iron ; and
this opinion is strengthened, when we recollect that the
native iron of Kamerdorf, and that of pseudo-volcanic
origin, present, in certain parts, a silver white colour.

I have not seen any mark of sulphurated iron, although
I found it by the analysis, as will hereafter appear.

All the fragments of this stone have a magnetic property,
but without polarity ; and the iron, which is very visible in
certain parts, is so disseminated in all others where it
escapes the eye, that the property of which there is ques-

* From Annates de Chimie oi March 18 10,

of a Meteoric Stone, 33

ti on, -manifests itself even in the smallest particles isolated
by trituration.

I found it even in the globulous bodies which are first
mentioned.

Pieces of this stone weighed from six to even 100 pounds,

ANALYSIS.

Having ascertained, by preliminary essays, that this stone
contained chrome, nickel, iron, manganese, lime, magnesia,
silex, alumine, and sulphur; I employed the following me-
thod of separating each of these substances.

1° 100 grains of this stone, from which the metallic iron
was isolated, by means of the magnetic needle, after being
pulverised, were treated with a considerable quantity of
water, through which was passed a current of oxygenated
muriatic gas : by this means, the sulphur being converted
into sulphuric acid, by the oxygen of the oxygenated mu-
riatic acid, sulphates and muriates were obtained.

2°. The whole was evaporated to siccity, and treated
with two parts of alcoholic potash : after fusion the mass
presented a fallow colour, and its dissolution in water was
of a fine yellow.

3°. The portions of the mass, which remained undis-
solved in water, were dissolved in an excess of muriatic
acid ; and being evaporated to siccity, I separated the silex,
which after calcination weighed 41 grains.

4°. Into the muriatic acid was poured carbonate of potash
in excess, which formed an abundant precipitate after an
hour of ebullition.

5°. The liquor contained sulphate and chromate of potash :
after being made acid, it was precipitated by muriate of
barvtes in excess, and there was obtained sulphate of bar\ tes,
corresponding to 2-^- of sulphur : and saturating afterwards
the excess of acid by an alkali, I obtained chromate of
barytes, corresponding to 2^- of chromic acid.

6°. The precipitate, No. 4, was submitted (still in a
humid state) to the action of alcoholic potash, and after
filtration, the liquor gave, by means of the muriate of am-
monia, a grain of alumine.

7°. Ammonia was poured into the remains of the pre-
cipitate, after having dissolved it in an excess of muriatic
acid. The oxides of iron and manganese were precipitated,
and the lime and magnesia remained in dissolution.

8°. The precipitate was isolated, and the lime separated
from the magnesia by the oxalate of ammonia, which,
after calcination, weighed three grains.

Vol. 30. No. 147.t/% 1810. C The

34 Proposal for an Iron Tunnel

The magnesia was precipitated by caustic polash : h
weighed, after desiccation, 16 grains.

u°. The oxides of iron and manganese were dissolved in
an excess of muriatic acid, and pouring, by little and little,
saturated carbonate of potash into the dissolution until red
floccules were visible, and then leaving it to repose 24
hours, all the carbonate of iron precipitated, whilst that of
the manganese remained in the liquor.

The carbonate of iron, after calcination, gave 24 grains
of oxide: and "that of manganese, deposited by ebullition,
by the same operation, only 1J-* — Which makes in all: —

Silex 41

Sulphur 24-
Chromic acid 2£

Alumine 1

Magnesia 16

Lime 3

Oxide of iron . . 30

Oxide of manganese ... . 1£
Loss 3

Total 100

Analysis of the metallic iron isolated by the magnetic
needle* 1°. 100 parts of this stone gave 28 of metallic iron,
which is very brittle, owing to the nickel it contains. 2°.
40 grains of this iron were dissolved in nitro-muriatic acid,
and by means of ammonia in excess the oxide of iron
was separated, which weighed 45 grains. The dissolution
of nickel in this alkali was evaporated to siccity to expell
all the ammonia. The oxide of nickel was redissolved
by muriatic acid, and precipitated by the prussiate of
potash, which gave one grain of the prussiate of nickel.
We may infer, from these physical characters, and results
of chemical analysis, that this stone is like all other me-
teoric stones hitherto known.

V. Proposal for constructing, and putting in its Place,
an Iron Tunnel under the River Thames. By Colonel
Lennox.

To Mr. Tilloch.

Sir, 1 herewith send you a plan for a tunnel under the
Thames, which I hope you will not deem unworthy of a
place in your valuable Magazine.

Being

under the River Thames. 35

Being informed that no particular plan has yet been de-
termined on by the Thames Tunnel Company *, they are
extremely welcome to adopt this if they think fit. 1 can-
not avoid encouraging a hope, that it will be found practi-
cable : but, should my partiality render me too sanguine in
favour of it, as the idea, 1 believe, is new, the publication of
it may lead to some other of more ingenuity, and which
may be easier and safer in the execution.

Explanation of a plan for constructing a tunnel of cast-
iron under- the river Thames : —

Fig. 1. A A, (Plate II.) section across the river. The
waving "line shows the present depth of the river; a a, the
additional depth required by the plan.

Fig. 2. B B B, three of the frames of which it is pro-
posed that the whole tunnel shall be formed : they are to
be of cast-iron, each of oik- piece, and to be joined together
by the flanchts ddd, which are all one foot broad a;* J four
inches thick, with the screws eee, in figs. 2 and 4, of four
inches, diameter, with half-inch sheet-lead between: — or
the joints may be secured with the cement employed by
steiMii -engine builders.

, Fig. 3. CC, section of the tunnel, showing the above
three frames, in figs. 2, in perspective ; each frame to be
ten feet in length, eighteen feet wide inside, and twelve
feet high at the sides; the top to be convex, rising two feet
in the middle; to be four inches thick at the bottom and
sides, and three at top. Each frame will weigh upwards of
forty tons t.

Fig. 4. DDD, elevation of the same frames, which
shows the screws that unite the exterior flanches, and also
the iron cramps, fj\ which embrace the two adjoining
flanches at bottom ; these cramps to be each twelve inches
broad, six inches thick, and two feet high.

Fig. 3. g g, tubes of eight inches bore, with openings
to receive leakage water, and to convey it to one o£, the
ends to be pumped out.

Hi, screw- holes. 'Hie dotted line kk expresses the
paving when the whole is completed.

* I believe the Thames Tunnel Company have settled the plan they mean
to follow ; but as the ideas suggested by Col. Lennox may prove useful oa
some future occasion, I have given it a place in this number. — Edit.

+ Should the carriage of pieces of this weight from the foundry be found
impracticable, the side*, and top and bottom, may be cast in separate pieces,
with flanches to join them at the corners. In this case the joinings of the
different parts may be so disposed thai no two of the transverse joinings
ghall coincide, which will give additional strength to the whole as every
joint may thks be supported with three solid pieces at that place in which
it £alis.

C2 By

36* Proposal for an Iron Tunnel

By the section across the river it appears that the depth
of the bed at low water (being only about 30 feet) is not
sufficient to admit of laying down a tunnel such as I pro-
pose upon the bottom, without obstructing the course of
the stream, or interfering with the ease of navigation :
therefore, the first thing necessary would be, to excavate
the bed of the river entirely across to about 1 6 feet deeper,
and from 6*0 to 80 feet wide ; and to render it as even as
possible throughout; which I conceive may be effected
without extraordinary labour or difficulty. This being
done as far as from b to c, fig. 1 , about 600 feet or some-
thing more, I will next suppose eighty of those frames,
previously formed agreeably to the plan and section, figs. 2
and 3, to be joined by screwing them strongly together,
as represented in figs. 2 and 4, with half-inch sheet-lead
between the flanches ; which operation should be per-
formed on the bank of the river rather below the level of
low water, in a situation where the tide may have free ac-
cess to it.

If then the ends of these 80 tunnel-frames so joined be
(when empty) close stopped with strong oak plank, and
well secured so as to render them perfectly water-tight, a
machine is formed iv hick on the admission of the ijde will
float ; as may be proved by the subjoined calculation,
which for greater security does not include the convexity
of the top. At spring-tide, therefore, the whole may be
floated to the required situation, and by additional weights
upplied sunk in its proper place. But in case of any irre-
gularity in its descent, or unevenness of the bottom pre-
pared to receive it, by removing those additional Heights it
will again become buoyant, when the necessary remedies
may be applied and obstacles removed. When once pro-
perly placed, by turning cocks fixed in each end it will
soon fill with water and be permanently bedded.

Calculation of the weight of this tunnel in round num-
bers : —

Cast-iron . . 20,020 cubic feet .... about 4,270 tons.

Lead 566 178

Oak 200 *

Tons . . 4,453
Water displaced 1,850,000 cubic feet ... 5,1 62

This tunnel will require to sink it more than 709
Exclusive of the convexity at top estimated at 60

Total . . 769

With

tinder the River Thames. 37

With respect to the manner of sinking this machine, I
propose that two short ropes of sufficient strength, with
loops at each end, should be passed over each frame, and
slightly secured to keep them in their places ; that when
the machine is floated to its destined situation, (which
should be about an hour before low water at the lowest
tide,) anchors and cables shall be in readiness to secure it
in its place ; and that then a number of boats (suppose 160)
shall attend, half on one side and half on the other, each
with five tons of ballast conveniently disposed so as im-
mediately to hook on to the ends of the short ropes before
mentioned, in such a manner that one end of the tunnel
shall not sink before the other, but both exactly together.
These weights may be so regulated as occasion may re-
quire, should there appear any irregularity in its descent;
and when it is placed as desired, and water admitted to fill
it, they may be removed altogether*. The whole of this
operation may, I am persuaded, be effected in two hours,
that preceding and that following ebb-tide, if every pre-
vious arrangement be properly made.

This part of the tunnel is then supposed to occupy the
space from b to c, fig. 1, and to be placed so as that the
upper surface of it shall be nearly equal to, or rather below,
the present bottom represented by the waving line. After
which, by piling off the tide from low-water mark, the
ends may be finished, as on dry land; which may be done
cither by a continuation of the same frames, or by arches
of masonry or of brickwork, as may be judged best. It
will then only remain to open the communication with
the middle part, by removing the oak planking at each end,
and pumping out the water; when, by laying a sufficient
quantity of ballast so as to form a road-way clear above
the lower flanches, and restoring the banks to their former
state, the tunnel will be immediately ready for use

In the execution of this project a situation should be
selected close to low- water mark, oF nearly 300 vards in
length, where it would be necessary to lay down blocks of
sufficient strength to support the great weight, and upon
which the whole 80 frames may be screwed together, the
level of which should be at least 15 feet below that of
spring tides to ensure its floating when completed.

It may be objected to this great machine, that from its

* Or perhaps the sinking may be conveniently effected by merely ad-
mitting from 800 to 1000 tons of water into the tunnel, a pump of suffi-
cient power being properly secured in each end frame to pump out 200 or
300 tons, should it be found necessary to float the tunnel again.

C 3 vast

38 Proposal for an Iron Tunnel, &c.

vast weight and great length, the power of 67 screws at
each joining would be inadequate to hold the whole per-
fectly together; and that in case of accident the whole
must be infallibly lost, as it Would then be impossible to
remove it from the spot on which it wonld immediately
sink, or even to separate the different parts of it. But as
the tunnel formed in the manner proposed will be sub-
1 to no particular force whatsoever at it* launching,
but be altogether equally borne up by the rising tide ; as
the weights necessary to sink it may he all so gradually
applied as to ensure its regular descent, to which the
form of the whole when joined as above, viz. convex at
the top and rising at the ends, together with the greater
thickness of the metal at the bottom, are circumstances
particularly favourable; and as from the nature of the
bottom it is sure to rest on a soft and uniform bed of sand,
on which it cannot meet with any object to occasion any
partial bearing, — I conceive the danger of accident is very-
remote, and the strength of the entire sufficiently secured :
besides, trials may be made in a sale situation.

The chief difficulty appears to me to be the excavation
of the bed of the river to the depth required. The best
mode of effecting this, or whether it would not be better
to choose another situation in which the existing depth
might be found sufficient, I leave to more able and ex-
perienced engineers to determine; stating merely, that as
the materials of which the tunnel is to be composed can
be procured for about ^44,000; allowing fifty per cent,
additional for all other charges incurred in its execution,
I do not conceive the expense would exceed the sum of
^66,000.

I beg leave further to add, that if it should be desired to
enlarge this tunnel so as to afford a foot-path in addition
to the space allowed for two carnages to pass, [ conceive
it may safely be done by giving it six more feet in width,
making altogether 24 feet between the interior flanches ;
and in order to afford it still greater strength, I would in
this case omit the interior lateral flanches, and in the room
thereof, applv plates of cast-iron of three or four in< hes
thick, the full height of the sides, to extend from the mid-
dle of one frame to that of the next, to be fastened bv a
number of the same kind of screws to the sides of the two
adjoining frames, with sheet-lead between and completely
covering the joint inside. This would give the tunnel
great additional strength without much increasing its
weight, besides that it would leave nearly a foot more of

free

Theorems on Musical Temperament, 39

free space inside; the increase of expense on this account
would not, I suppose, much exceed twelve or fifteen thou-
sand pounds, in addition to that before stated.
I am, sir,

Your obedient humble servant,

Bath, June 1810. W. Ca; LFIELD LENNOX.

VI. Six Theorems, containing the chief Properties of all
Regular Douzeave Systems of IvJusic ; with Twelve Co-
rollaries thence deduced, showing others of their Relations ;
and Thirteen Scholia, containing the Temperaments of as
many Systems, calculated thereby. With Remarks. By
Mr. John Farey.

To Mr. Tilloch.

Sir, A am much pleased to observe, that at length a be-
ginning has been made, at publishing tables of the Beats
in 15"; made by the 72 concords in different systems of
Musical Temperament, by your new correspondent Mr.
C.J. Smyth, of Norwich, in your last Number, who will,
I hope, persevere, and give us tables of many other sy steins,
accompanied by such critical remarks, on their comparative
merits and detects in praciice, as he appears well qualified
to make, either m your Magazine, or in the separate work
which he has announced on the subject.

Some time ago, I had thoughts of preparing a work on
Harmonics, perhaps as a kind of supplement to Dr. Robert
Smith's justly celebrated work ; but the prospect being now
rather distant, of my being able to find leisure to complete
this design, I am induced by the above paper of Mr.Smvth's,
and the publication of a small work on Harmonics, by Mr.
J. Marsh of Chichester, to transcribe from my papers some
Theorems, showing the properties of regular douztaves, or
of such systems pr twelve notes in the octave, as have all
their fifths alike tempered, except, that between *G and
bE, when there is a bearing fifth or quint wolr": but first I
beg to make a few remarks.

In douzeaves, or systems of twelve notes, there are geT
nerally 16 wolves or tempered concords, differing* from

* Wolves, taken in their general sense, are not always larger than the
temperaments, but may be equal to them, as happens throughout the iso-
tonic or equal temperament scale, and may even be le.-s ;han their re-
spective temperaments, in some cases, as in scholia 1 and 7 ; they are, in
fact, the places in the douzeave or other defective scales, where the resulting
intervals or unavoidable inequalities fall, and, as such, are very important
to be known and attended to by the compoiers of music, to be performed in
fuch scales.

C 4 the

40 Theorems on Musical Temperament.

the temperaments proper to the six several concords re-
spectively.

In regular douzeaves, none of these wolves occur, in
any of the six concords, upon any of the four middlemost
key-notes, viz. G, D, A or E respectively.

C, F, bB and bE have no wolves in their major concords
(i e. the III, V or VI upon them, re-
spectively.)

B, *F, *C and *G have no wolves in their minor con-
cords (i. e. 3d, 4th, or 6th.)

Whence it follows (see Dr. Smith's Harmonics, Plate
XIX, p. 162, 2d edit.) that in major Keys, modulation can
be made from C by *s, through the keys G, D, A and E
without false concords or wolves; but if we proceed further
by *s, B has a false III, *F has its III and VI false, *C has
its III and VI false, and *G has its V, III and VI false,
which last chord Mr. Smyth calls the wolf, by way of
eminence, p. 450 of last volume.

And in major kevs, modulation can also be made from
C by bs, through F, bB, and bE, and no major wolves occur,
(yet bE has a false 4th) ; but on proceeding further to bA
(or *G) its V, III and VI are false, as above.

In minor Keys, modulation can be made from A by *s
through E, B, * F, *C, and *G, without any minor wolf (yet
*G has a fa'se Vth),but on proceeding further to *D (or bE),
its 4th, 3d and 6th are false.

And in minor keys, modulation can also be made from
A by bs through D and G, without anv false concords or
wolves ; but on continuing thus to modulate, C has a false
0th, F has its 3d and-6th false, bB its 3d and 6th false, and
bE (or *D) has its 4th, 3d, and 6th false, as above.

The six following Theorems, express in terms, of the

r t

fractions and — (either proper or improper) of the small

intervals Schisma and most Minute* or 2 and m, all the
temperaments and wolves of the 72 concords, in any re-
gular douzeave; and whence, such temperaments can
rrad.ly be calculated for any proposed system, or the va-
rio s properties and relations of its intervals can be dis-
covered and computed : and by means of other theorems,
the beats can be calculated from such temperaments, in
terms of £ and m. In the article beats in the " Edin-

• See vol. xxviii. p. 142, and engraved table, plate V.

burgh

Theorems on Musical Temperament. 41

burgh Encyclopaedia," such a set of Theorems will shortly
be given, with examples of the use of each, as will perhaps
supersede the necessity of publishing them in your Maga-
zine.

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Theorems on Musical Temperament*

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Corollary

T/ieorems on Musical Temperament. 43

Corollary 2. The sum of the 11 temperaments of the
minor fourth, and its wolf, is constantly 122 -fm, as
observed above.

Corollary 3. The sum of the 8 temperaments and 4
wolves of the major thirds, is 842 + 8m, or four en-
harmonic Diesises.

Corollary 4. The sum of the 8 temperaments and 4 wolves
of the minor sixths, is —842 — 8m, as above.

Corollary 5. The sum of the o temperaments and 3 wolves
of the minor thirds, is —962 —9m, or three Semitones
minimum.

Corollary 6. The sum of the 9 temperaments and 3 wolves
of the major sixths, is 962 -f 9m, as above.

Corollary 7. The sum of the temperaments of the minor
third and of the major third, is equal to the tempera-
ment of the fifth.

__ 3r— lis lis— Ar — r

For H = , the first part of the

temperament of the fifth, and so of the latter part. —
(See Dr. Smith's Harmonics, cor. 6, p. 42.)

Corollary 8. The sum of the temperaments of the fifth

and of the major sixth, is equal to the temperament

of the major third.

„ — r lis— 3r 115— Ar , — t u—3t

For f- = 2: also f-

s s s u u

u—At lis— 4r , u— At . .

_ m,or 2 -\ 'm, as in theorem 3.

u s u

(See Dr. Smith's Harmonics, cor. 8, p. 43.)

Corollary 9. The difference between the wolf and the

temperament of each of the six concords resncc-

. . . . . 12r— 12? 12/— v
tively, is the same, viz. 2 ~\ m, and is

-5 ' s u

what Dr. Smith, at pages 1 60, 223, &c. calls the Diesis ;

it is the difference between adjacent flat and sharp

notes, as between *D and bE, *A and bB, Sec. p. 163.

I, llr— 12s — r 12r— 12-5 . 11/—?/ — t

por -s 2, and

s s s ^ u u

\2t—u . . rc, A1 Sr— s lis — Ar

= m, 111 the fifths. Also, — =

u ' s s

Ur— 12* . 8/ u— At \2t—u .

2, and = m, in the ma-

s u u u

jor third, as before, and so of all the others,

Corollary

44 Temperaments of different musical Systems.

Corollary \o. The minor Lim ma of Dr. Smith, p. 223,

or the value of a sharp or a flat, is, 2 -f- f -f-

5u—7t . . _fc . 58"149()5— 7r
— m: or, without f*, we have • • t-

5 0]36u-7t

. m.

u i
As is easily deduced from my theorems above, by
the process in page 158, of the Harmonics. As is
also the following,

46$-f-5r

Corollary 1 1 . The major Limma of Dr. Smith is 2

4u + 5t . - . 46-1496j + 5r_,
_j_ f j m. or, without i, we have : 2

1 • - :w ' • •' ^

40130M + 5*
-f m.

Corollary 12. The wzeaft Tbra* of regularly tempered sy-
. J04*— 2r _ 9^—2/
stems, is -2 -f 2r -| m; or, without

104'2992^2r Q'0272v-2t

f we have 2 -f m.

s u

By multiplying these general Corollaries, I should, per-
haps, exceed your limits. I must therefore content mvself
for the present with the following, as particular applications
of the theorems and corollaries above, viz.

Scholium ] . If a douzeave he required, in which the fifths

should be perfect, we have by theorem 1, \ =0;

which condition will be answered, if r and / each ^= 0
and s and u each = + 1 5 which values substituted in

the fifth wolr 2 -\ -m, gives — 12 2

s u ' &

— m as it ought to do, by cor. i.

. . lls-4r u—At
Also, m theorem 3, ■ 2 4- m gives 112

-f m or c, a major comma, as the sharp temperament
of each major third in this system ; also in theorem 6.
l]5__3r ' u— 3t
2 -| m gives 1 12 +m or c, as the sharp

* By an examination of plate V in your 28th volume, and of a more ex-
tensive table of Intervals, it appears, that the number of 2s, always exceeds
the number ofm's in ratios between those of 12*5 : 1 and 10*: 1 (those of
Sand g). But the major comma and its aliquot parts, most frequently
occurring; in temperaments, I have adopted its ratio of 11 1 1, and thus find
f = -H062 + *Oi:56m ; from which equation, the latter ones in cor. 10, 1 1
aud 12 are obtained. tem-

Temperaments of different musical Systems* 45

temperament of the major sixths ; which last tem-
peraments prove the same as they must do, to fulfil
the conditions of cor. 8.

Though the fifth wolf is here so large, the Illds and
Vlths wolves are each 2 only.

This system approaches very near to that of Mer-
cator, wherein the octave is divided into 53 equal
parts, and where — -0350942 is the flat temperament
of the fifth. See M. Sauveur's general table of tem-
pered systems, Mem. de l'Acad. 1711, lomo. p. 416.

Scholium 2. If a douzeave be required, in which the ma-
jor thirds should be perfect, we have in theorem 3

'lis- 4r s". , r 11 w— At

= o, or lls = 4r, whence — = — ; also

s s 4 u

= 0, or u — At and — = — j whence it appears, that

the fifth is to be flattened —2 + -ra, or — c: and,

4 4 4

by substituting the above values in the wolf, the same

appears to be 212 -f 2m, as in cor. 3; and by the same

in theorem 6, we get —2 -f ~rra' or "Vc* tne snan?

temperament of the major sixth ; the same with that
of the fifth ; see cor. 8.

This is the Mean Tone system of Salinas. Zarlino,
Aretinus, &c. Dr. Smith's Harmonics, p. 36,41,&c.
wherein the adjaceat flat and sharp notes are distant
212 -f 2m, or an enharmonic Diesis, as appears by

r t

substituting; the above values of — and — in cor. Q.
P s u

It is also nearly the same with a division of the
octave into 112 equal parts, (see M. Sauveur's table
above quoted), wherein —2*82902 is the flat tempera-
ment of the fifth; — c above, being — 2«7519662.

Scholium 3. If a douzeave be required, in which the major

sixths should be perfect, we have in theorem 6,

r 11 . u—Zt
= 0, or 1 lj = 3r. whence — = — ; also = o,

1 l i 11 „ 1

or, u — Zt\ whence — = -.-, and —2 -f- -— m, or,

- — c, is here the flat temperament of the fifth : and by

sub-

46 Temperaments of different musical Systems.

substituting the same in the wolf we get 322 -f- 3m ;
as in corollary 6; likewise in theorem 3, we have

—2 -f — m, or — c, the sharp temperament of the

3 3 3

major third also, as is consistent with cor. 8. The

II Id and Vih wolves are here each 28£2 + 2*m. (See

Harmonics, p. 42.)

This system approaches very near to a division of

the octave into 19 equal parts, where — 3*(>Q472 is

the flat temperament of the fifth, (Dr. Smith, Har-

1 3 47

monies, p. 158, makes it — -— c --c = — -~j-c

or — 3-6955Y); — - c above, is — 3-6602S82. See

o

M. Sauveur's table.

The cases of equality of temperaments between the
III and VI, and between the V and VI having occur-
red, in schol. 1 and 3, I proceed to

Scholium 4. If a douzeave be required, in which the
major fifth shall be as much tempered flat' as the
major six th is sharp ; from theorems 1 and 6 we have

— r lls—3r ; r 11

= or Hi — 2r: whence — = — ; also

s s s 2 '

— t u—3t , t I a

= , or u = 2t: whence — = -— : and - 2

u u u 2 ' 2

4- — jBj.or— c, is here the temperament of the
2 2

fifth : and by substituting this value in theorem 6, we

have 2 -J- — m, or -— c, for the temperament of

222

the major sixth also. The V and VI wolves are here

each 48^2 + 4^m.

Scholium 5. If a douzeave be required, in which the major

fifth shall be as much tempered flat as the major third

is tempered flat; from theorems 1 and 3, we have

— r 4r— lis . r 11

■ — = , or 5?== 1 15 ; whence — = — : also,

s s , s 5 '

-1 At-u t 1 4 n

= or bt — iu whence — = — : and - 2

u u u 5 ' 5

4- — m,or — c, is here the temperament of the fifth:

and by substituting this value in theorem 3, we have

-—2 -f — m, or — c, for the flat temperament of the
5 5 5

major

Temperaments of different musical Systems, 47

major third also: the temperaments of the major

22 2 2

sixths being r 2 -f- — m, or — c.

5 o o

This is the system of Mr. John ITolden, since me-
tamorphosed into an irregular douzeave in the article
Monochord, Enc. Brit. 3d edit. vol. xii. p. 240, and
into a still different one, by the Rev. Mr. Hawkes. (See
your xxvith volume, p. 171, and xxxih volume, p. 5.)

It also approaches near to M. Sauveur's system of
43 equal parts in the octave, (see his general table
above referred to) wherein —^ 11 772 is the fiat tem-
perament of the fifth ; --c above, being —2*2015732.

One other case of this kind, viz. where the major
thirds are tempered flat as much as the major sixths
are tempered sharp, will be found to arise from dif-
ferent considerations in scholium 11.

Scholium 6. If a douzeave be required, in which the tem-
perament and wolf of the fifth shall he equal, we have
from theorem 1, — r = 1 \r— 125, or 12r = 125, whence

r 1 . ; *

— ±= — : also —t = 11/ — iu or 12/ = ?/, whence —
si 7 u

= — -, and 2 + -~ m, or — c, is the flat tempera-
\ & J i> li

ment of the fifth, in this case: and which substituted

in theorem 3, either for wolf or temperament, gives

2 7

72 4- -^-m, or ■ -c, the sharp temperament of the

4. 3

major third; also, in theorem 6, gives 82 -\- ~~tn9

8
or - c, the sharp temperament of the major sixth.

This is the Isotonic or Ecjual Temperament Svstem of
Mersennus, &c. called bv Mr. Marsh and others,! hough
improperly, the Equal Harmony System (see scholium
10). See vol. xxix. p. 347 : see also Dr. Smith's Har-
monics^. lSSand 1(37. In the latter page, however, ihe
temperaments of theVth,VIth and i I Id are mistakenly

said to be •— , — and 1Q , instead of --, -- and —

of a comma, lis they are above, very nearly.

Scholium 7. If a douzeave be required, in which the several
wolves shall differ from their respective temtieromnifs,
ly the least known Interval or most Minute (m): ue

have

4ft Temperaments of different musical Systems.

. c „ 12r— 12s

have from corollary 9, =0, or 12r= 125 J

, r 1 . 12/— m * O

whence - = — ; also, = — I, whence — = — .

s 1 * ■ u ' u 1

By which we obtain in theorem 1, — 2 as the flat tem-
perament of the fifths, and — £ —in its flat wolf: also,
in theorem 3, we get 72 -f-m the sharp temperaments
of the major thirds, and 72 their wolves ; and by theo-
rem 6, we obtain 8S + m the sharp temperaments of
the major sixths and SS their wolves.

This is my Equal Temperament Syste7n, whose tem-
pered fifth, and consequently all its other intervals,
can be tuned on an Organ by means of perfect intervals
only, viz. 5 4ths — 3 Vths — III = V— 2. (See vol.
xxviii. p. 65) ; such tuning to be upwards from C as
far as bA and downwards from c as far as bE, between
which notes, the wolf 2 -f-m, will result. The beats
calculated by Mr. Smyth, at page 452 of your last
volume, belong in fact to this system, and not to the
strict Isotonic above, but the difference in practice
would be imperceptible between these two systems.

Scholium 8. If a douzeave be required, in which the ratio
of the temperaments of the major thirds shall be to
their wolves as 1| to 3^*, that is, or as 5 to 14, we

have from theorem 3. As 5 : 14 : : : — — — ;

s u '

whence 1545— 56r =40r— 5s, or 1595 = 96V, and —

53 . u-4t 8t .
«* «« 5 a'so5 as 5 : 14 : : : — - . whence 14w-~

32 ' ' u u '

t 7 53
56/ =40/,or 14//=96/, and — = - --: and 2 —

9 ' » 48 32

7
-r— m is the flat temperament of the fifth, which sub-

300/ 20

stituted in the first theorem gives ~^r^ -f -7 -my

* Nfr. Marsh, assuming the true major third to be 48 degrees or parts,
states, the tempered III to be = 49^, and the wolf or " extended third," (as
he elsewhere calls it) to be 51$ parts: in the system which he most ap-
proves; I therefore take the excess of these above the !Ud,as giving the ratio
of his temperament and wolf, in order to obtain the values of his notes in my
theorems. It is not however clear, that such is exactly his meaning ; since,
150 being assumed as the measure of the octavr> the values of the major tkud
and of the diesis can be no of her than 48-28921, &c. and 5*132378, &c. o?
very nearly in the ratios of 6122, 1972 and 212 : and it is not possible for
48 and 6 truly to represent the major third and diesis in such octave» or to
any other.

the

Temperaments of different musical Systems. 49

the sharp wolf. In theorem 3, we.get the sharp tempera-

3 5

ment of the major third = ft- £ + — m, and its wolf

1 "*

= 12-2 + fim. And intheorem6, the sharp tempera-
ment of the major sixth = 6-- 2 +~m. and its

ir 20 21

wolf IS^*.+ To-m.

This is Mr. J. Marsh's approved method of tuning
a douzeave. Theory of Harmonics, page 13.

The system nearest to this of any which I remem-
ber to have met with, is that of a division of the oc-
tave into 67 equal parts, (see M. Sauveur's table above
referred to), where — 1 '764552 is the flat temperament
of the fifth , which here is — 1*65742; and the same
differs considerably from the other system recom-
mended by Mr. Marsh page 18, which, perhaps after
the example of Dr. Smith, he has borrowed from
M. Henfling without acknowledgement. See my 10th
scholium.

By Dr. Smith's Harmonics, ed edit. p. 84, prop.XI>
latter part of cor. 3, f when the bases and beats (of
two tempered consonances) are the same, the tempera-
ments have ultimately* the inverse ratio of the major
terms" of the perfect ratios of these consonances.
Whence

Scholium 9. If a douzcave be required, wherein the Jiftk

(■§-) and the major third [$) to the same base shall beat

equally quick, the former flat and the latter sharp ; we

•— t lis— At

have from theorems I and 3, as 5 : 3 : : :

s s 9

whence 55s— 20r= — 3r, or 55s=23r, and — = -- —

' s 23

_/ u— At .
also, 5:3:: : , whence 5a— 20/= —3/,

3 u u ' *

* The ultimate ratios are in tkese cases, very near to the exact ratios :

thus in scholium 9, — -c, or 2-2930132, results from the ultimate ratios ;

the true temperament being '2-S93G932, as derived from the length of string
I of the Vth, in the equation 4/* — P — f ; the difference being lels than

th of a X, an interval altogether imperceptible in practice.

Vol. 36. No. 147. July 1S10. D 01

50 Temperaments of different musical Systems.

t 5 55 5

or 5?z = 23/, «»(l7,-=-^; a»d T£"s + "£Jm or

— c is the flat temperament of the fifth. In theorem

3 17

3, we get 18 -,-S + IfirW tne sharp temperament of

12 22

the major third; and in theorem 6, 20 ---- -f 1 — m

the sharp temperament of the major sixth.

This is the syftem for defective scales which Dr. Smith
describes, and recommends, p.icres 219, 215, 1S9> 211,
and 212: and of which Mr. Atwood has (but without
acknowledgement) given the lengths of strings in his
" Rectilinear Motion, &c."

A system, wherein the octave is divided into 74
equal parts, to be found in M. Sauveur's table, and
where the temperament is V — 2*38382, differs but
very little from V — 2-39301 52 m this system.

Scholium 10. If a douzeave be required, wherein the fifth
(}) and the major sixth (f ) shall heat equally quick,
the former flat and the latter sharp : we have from
, ' r lis— 3r

IIICUI

cms

I <

1UU u,

•AS 3

: o :

• „

'

s ' ,*""™

55s -

- \5r

=

3r, or

55s =

: ISr

and

r

s

55
= — ; also, as

5 : 3

t
u

- :

u—3t
u 5

whence i

5a—

\5t-

■3t or 5u^=\St

and

t
u

5
18

-; and

l
3 1 8

X +

5

18

m or

5

— -c is the flat
18

temperament of the fifth: which in theorem 3, gives

v _ — m or — c for t_ne flat temperament of

9 9 9/ [

the major third: and in theorem 6, gives -^-2 -f-

. m or -~ re, the sharp temperament of the sixth.

This is the famous System of Equal Harmony in
3 octaves, invented by Dr. Robert Smith. See his
Harmonics, pages 216, 191, 206, 212, 214, &c.
And differs but little from M. Ilenfling's system,
(Mem.de l'Acad. 1711, 16mo, p. 40S), wherein the
octave is divided into 5o equal parts, as Dr. Smith
shows in his Harmonic?, p, 157, and states its fifth to

be

Temperaments of different musical Systems. 51

1 1 41

be flattened -c """37° or ~""l48~C' whic^ ls

— 3-049662; or more correctly it is — 3*048112; — c

being —3*057742 in the system of this scholium.

Scholium 11. If a douzeave be required, wherein the
major third (±) and the major sixth (f) shall beat
equally quick, the former sharp and the latter flat ;

115— 4r
we have from theorems 3 and 6, as 5 : 5 : : — :

3r —11?

, whence 11 5— Ar = 3r — 1 Is or 225 =7^ and

s J

r 22 , u — At Zt — u .
= — -• also, as 5 : 5 : : : , whence

s 7 u u

t 2 22

u — At = 3t — u or 2u = It and — = — ; and -— -S

2 2

4- - -m or -- c is the temperament of the fifth.

Which in theorem 3, gives — 2 '— — - m, or—c,

the flat temperament of the major third; and in theo-
rem 6, gives —2 + ~m, or — c, the sharp tem-
perament of the major sixth*.

This is the system which Dr. Smith ' barely
mentions at page 2203 011 account of its dif-
fering so little from equal harmony, in my last

5 35

scholium; wherein -— - or -t^c is the tempera-
18 120

2 36

ment of the fifth, which here is — , or — — - : the dif-

ference being only the -rr~-th part of a major comma or
1 20

•0873642: also - or -^-, and —• or JL have, a

difference of v-^-c, or '349462, but little more consi-

1 7 1

derable, in the major thirds ; and ~x- or , and —

J 0 42 '. 7

f\ 1

or -— have a difference of — c, or *262092 in the

major sixths.

This system differs more from that of M. Henfling;

* Mentioned by .Dr. Robison, Sup. Enc. Brit. 3d edit. ii. 662,

D 2 (see

3*2 Temperaments of different musical Systems,

(see Sauveur's table above referred to) than the last,

2 #

since — c = —3* 145 IS, and in his system — 3*048112:

is the temperament of the fifth*

Scholium 1 2. If a douzeatfe be required, wherein ike mean

Tone thereof is to its major Limftta as 5 to 3, we have

P '. . 104-29025 — 2r

from corollaries 11 and 12, as 5 : 3 : : - :

. s

40'-14Q6.« + 5r

- , whence 230*7 180s + 25r = 312- 8976\? —

$

i r 82-1406
or, or 82*14965 = 31 r, and — = — -^~ -• also as 5 :

O-0272K— 2* 4*0136m + 5*

3 : : -2 — - : — , whence 20*0680w +

u u 3

Q5t = 27*08 16a — 6/, or 7*01 36m = — 3H and — =

u

—7*0136 , 82-1496 7*0136

— ~ : and -~ -2 - 0, m is the flat

31 ' 31 31

temperament of the fifth.

This is the system of M. nuygens. (See Dr.

Smith's Harmonic:, pages 158, lOS, 121, 208,

£124, Sec.) whose temperament of the fifth, as calcu-

11 53

lated by Dr. Smith, is - — c + - Qc or - -- c, «=

2*65192; mine above being about 2*65182.

The octave here is supposed to be divided into 31
equal parts. See M. Sauveur's table ; Mr. Ambrose
Warren, in 1725, pretended to the discovery of this
system. See Monthly Magazine, vol. xxix. page413.

Scholium 13. If a douzeave br* required, wherein the mean

Tone thereof is to its major Limma as 9 to 5, we have

c .. . . 104-2QQ2$~2r

from corollaries 11 anU 12, as 9 * 5 : : ■ :

5

46- H965 + 5r

— - — - — --, whence 415*346l5-f 45r = 521 '49605 —
s

, r 106-1496
lOr, or 55r= 106*14965, and — = 7T > a5so

90272a -~1t 4-0136w-f5<

as 9 t 5 : : — ; : , whence

• u u

36*1224tt-}-45£ = 45*13te— 10/,or9'0136// = 55f and

/ 9*0136 . 106*1496^ 9*0136

_«b 2- rj and t~-^ — ■—; — m is

u 55 ' 55 55

the flat temperament of the fiith, = —1*93 132

Thi*

Report on the Memoirs, &c. 53

This system answers to a division of the octave in-
to 55 equal paits, and according to tii<- papers of
M» Sauveur in Hit Memoirs of the Paris; a.:. Academy,
for 1707 and !7 11, W vvas the system used by m
Musicians of Paris at or previous to that time. See
his general table of tempered systems above referred to.
I am, sir,

Your obedient humble servant,

Westminster, July 11, 1810. J. FAREY.

VII. Report on the Memoirs presented to the Society of
Pharmacy at Paris, in consequence of the Prizes offered
in the Year 1809. Extracted by 37. Bouillon La-
grange from the full Report drawn up by Messrs.
Nachet, Dejiosne, and Vallee.

KJj nine memoirs sent to the Society, two have particu-
larly fixed the attention of the committee. They were
written in answer to the following question :

44 To prepare the acetate of potash, so as to obtain it white
and saturated, without employing radical vinegar, and
without having recourse to fusion ; — to point out which of
the two, the acid or the alkali, gives it the colouring prin-
ciple. "

The first memoir, with the motto Ex cognitis incognita,
is written with great precision.

The author, alter having ascertained the advantage which
would result from obtaining this salt in all its purity by a
simple and (Economical process, begins by inquiring from
whence the colouring principle arises : It cannot, he says,
be owing* to the alkali, when it is considered that the fusion
of the acetate of potash renders it insoluble, and that the
heat requisite for this fusion is not so strong as that which
is necessary tor the preparation of anv given potash; and
on the other hand, it cannot be essentia! to the acetic acid,
when radical vinegar is capable of instantly furnishing a
colourless salt. Consequently, this colouring principle
must be a foreign substance contained in common vinegar,
and which may be introduced into it it) distillation. But
this same principle is less volatile than the acetic acid,
since distilled vinegar leaves a residue of it if we evaporate
it a second time : it is not very soluble by itself, and it
cannot be dissolved except by the addition of acetic acid,
since it is precipitated, at least in part, when we saturate the
latter bv potash: and iinallv, it has been ascertained that

D 3 it

54 Report on the Memoirs presented to the

it is of a vegeto- animal nature, cither from the smell which
it exhales when placed on hot coals, or hy the prussiale
of ammonia which upon distillation furnishes the acetate
of potash prepared with distilled vinegar: a product
which does not give the same salt prepared with radical
vinegar : w hence the author concludes that the radical prin-
ciple which colours the acetate of potash is no'hing but a
part of the ferment of common vinegar, carried into the
distillation and more or less altered bv this operation.

Independently of this colouring principle, inherent in
the constitution of common vinegar, the author of the
memoir mentions another still more capable of making
the acetate of potash look brown: this is the empvreumatic
oil with which the vinegar is charged when the distillation
is carried too far. He further says, that this salt may also
be coloured by the oxides of iron and of manganese con-
tained in the alkali, or by the metallic utensils used in its
preparation : but this colour being merely accidental, we
may avoid it entirely by using a pure potash and vessels of
tin or porcelain. We must therefore adhere to the fer-
ment and the empyreumatic oil. The following directions
'are given for avoiding these two colouring principles: the
ferment may be separated from the acetate of potash the
more easily the less of it there is in the distilled vinegar,
and the latter will contain so much the less in its turn ; as
in common vinegar, the proportion of the ferment will be
smaller with respect to that of the arid, on account of the
quantity of ferment brought over in distillation being al-
ways more or less in proportion with that which exists in
common vinegar. It follows therefore that it is necessary,
above all, to employ common vinegar, which is at once the
most acid and the least charged with ferment; and this re-
quisite may be attained by choosing a clear vinegar, be-?
sides being very strong and completely fermented. After
the choice of the vinegar, the process of distillation may
also have some influence on the quantity of the ferment
contained in distilled vinegar: for, since this principle is less
volatile than the acetic acid, the less of it will pass over in
distillation, the more slowly this process is conducted; and
in this respect we may admit a slight ebullition as being
the fittest degree of heat.

If the preceding rules have been well attended to, the
distilled vinegar will contain so small a quantity of fer-
ment that it will be capable of furnishing immediately an
acetate of potash almost entirely colourless ; but if, not-
withstanding every precaution, the whiteness of the salt

still

Society of Pharmacy at Paris. 55

still leaves something to be desired, there remains a final
method of remedying it, which consists in filtering through
charcoal in powder. The action of this" substance, although
little known as to its theory, is nevertheless certain in its
effects ; since it is sufficient to boil slightly with it the so-
lution of the acetate as above prepared, in order to obtain
it perfectly white after filtration and evaporation carefully
managed. As to the empyreumatic oil, there is only one
wav of avoiding it, which is to stop the distillation of the
vinegar at the moment when this principle begins to come
over, and the product gives out an empyreumatic smell :
for, beyond this term, the vinegar, if still white in appear-
ance, would not undergo any change of colour during the
evaporation of the acetate; and this colour, when once
produced, could not be removed, either by charcoal powder
or by any other means whatever.

The second memoir presents fuller details. Its motto is
taken from Boileau :

" L' artifice agreable
Du plus affreux objet fait un objet aimable." ,

The author describes in the first instance the various
processes hitherto adopted in preparing the acetate of potash.
He mentions as the most exact the process of M. Bouillon
Lagrange, which consists in crystallizing this salt ; but he
regrets not having been able to put it in practice, from the
difficulty of separating the crystallized acetate from the mo-
ther waters, which are very thick. In order to obtain as ad-
vantageous a result by a more practicable process, he tried
double decompositions ; he treated acetate of lime with the
carbonate or sulphate of potash, but he did not obtain an
acetate of potash less coloured than if he had directly sa-
turated the carbonate of potash with distilled vinegar.

It would be necessary, as he observes, to employ a cry-
stallized acetate of lime, but in this case the process would
become too tedious and expensive. The decomposition of
the common acetate of lead by the carbonate of soda, fur-
nished him with a tolerably white acetate of potash : al-
though this method unites with the facility of using it the
advantage of being cheaper, the author of the memoir does
not think it right to resort to it, because the smallest neg-
ligence in the operation may change a wholesome medicine
into a deadly poison. Recurring to the combination de-
scribed of distilled vinegar and potash, he first inquires
whence arises the colour assumed by this salt during its
evaporation : he is also aware that it is owing to a foreign
principle contained in the distilled vinegar; but he after*

D 4 wards

56 Report on the Memoirs presented to the

wards s:uv that this substance was very slightly of a co-
louring nature by itself: he observed that the acetate of
potash well saturated, is found a> a consequence of its eva-
poration with an excess of alkali ; and it is this excess of
alkali which reacts on the foreign principle contained in
the distilled vinegar, and colours it. In order to show
more clearly this reaction of the potash, he divided into
two equal portions a solution of acetate of potash : he eva-
porated both at the same degree of heat, maintaining con-
stantly in the one an excess of acid, and in the other an
excess of alkali : the salt produced by the liquor with ex-
cess of acid was much less coloured than that furnished by
the liquor with an excess of alkali *. After having ascer-
tained the origin of the colouring principle and the cause
which develops it, the author next endeavoured to destroy
it; and charcoal in his opinion is the fittest agent: with,
this view he filters the distilled vinegar through charcoal,
he then saturates it with carbonate of potash, leaving in it
an excess of acid, which he takes care to keep constantly
in the liquor during its evaporation. The result is an ace-
tate equally white with that obtained by means of fusion.

This process, although very simple, did not appear to
him to be practicable, because the acetate of potash is
mixed with a certain quantity of acetate of lime, to which
the lime contained in the charcoal has given rise; and this
salt, by altering the purity of the acetate of potash, retards
its desiccation. It would, indeed, be very easy to separate
it by adding a slight excess of carbonate of potash, in order
to precipitate the lime j and we should afterwards put in an
excess of acid : but it is easier to saturate the acid first.
The following is the process as described in the memoir:

Pour into distilled vinegar a solution of carbonate of
potash, until no mere carbouic acid is extricated: after-
wards evaporate the liquor, taking care always to Keep an
excess of acid in it : when it is reduced to three-fourths,
allow it to cool, in order to separate from it the sulphate
of potash and some impurities; decant it in order to heat
it, and pour it when hot on a charcoal filter f.

* We have reason to believe, from our own experiments, that the potash
st'll reacts, but much less on the colouring principle, even when the liquor
contains an excess of acid •, since by operating in this manner we always
obtain an acetate cf potash which is more or less coloured, whilst the same
vinegar is capable of furnishing acetate of lime, magnesia, and aluminc,
wh»ch are very white. Soda did not appear to us to act so strongly as
potash on this principle. — Kmte ty the ConuutHet.

f The acetate of lime when dried is less deliquescent than the acetate of
potash, and yet it is much more difficult: to produce the desiccation of it. —
■Note hj the Juihor. If

Society of Pharmacy at Paris. 57

If the filtered liquor does not contain more free acid,
add a little di-nilied vinegar *; then evaporate to dryness ;
and if we wish to obtain the acetate of potash well cleaned,
we must, at the end of the evaporation, manage the fire
properly, and not stir it; but in this case it is not so white
as when we separate it with a silver spatula, and throw it
on the edges of the basin as fast as it is formed at the sur-
face of the liquid : this salt will also be whiter it' dried by
small portions.

On exposing for about 20 davs to the solar rays the
liquor filtered over charcoal, the author obtained a salt
much whiter: hence he thinks that the same result might
be obtained, by exposing la the light an acetate of potash
made from distilled vinegar, without being filtered through
charcoal.

He regrets that he has been unable to collect some
important facts relative 10 the colouring matter: he re-
marked that it was partly ,.recipitated after saturation ; that
it is a little soluble in water, and that a portion remains in
solution in the liquid acetate of potash; that after having
filtered distilled vinegar through very pure charcoal, like
that which is produced from crvstallized sugar, we no
jonger obtain, on saturating it with crvstallized carbonate
of potash, the same precipitate as before filtration.

The author of the memoir concludes, therefore, —

1. That the colouring matter of the acetate of potash be-
longs to a vegetable substance contained in distilled vinegar.

2. That this colouring matter is destroyed by charcoal.

3. That an excess of alkali, when we evaporate the result
pf the saturation of distilled vinegar by potash, may in-
fluence the whiteness of the acetate'of potash.

4. That in order to obtain the earth pure white and sa-
turated, it is sufficient to filter a concentrated solution of it
over a small quantity of charcoal in powder; to keep in it
afterwards to the end of the evaporation an excess of acid,
by adding from time to time distilled vinegar, and to ex-
pose it for some days to the solar li|$ht.

Jn a note which terminates this" memoir, the author
says, that according to the valuable observation of Messrs.
Vauquelin, Pou tier and Derosne, he .obtained two hecto-
grammes i,f excellent acetic ether, by rectifying over pot-
ash the first products of the distillation of 70*litres of distil-

< * A little acetic acid (radical vinegar) would he preferable ; very little
» Decenary when care has been taken to iilter the liquor in the neutral
•dates we must also take care that it is not acid, in consequence olfhe H-ne
wi^ch is in ;he charcoJ. ^^c

-58 Of the hifluence of Solar and Lunar

The committee carefully repeated the experiments de-
tailed in the above memoirs. Jr' we except the whitening
effects on exposing the acetate to the sun, which did not
succeed with them, they pronounced them to be all cor-
rect ; indeed, the principal agent in the. whitening process
was already known. Lowitz has recommended the use of
charcoal, in order to obtain an acetate of potash less coloured
than by the ordinary process ; but whether he has not suffi-
ciently described the method of using it, or employed vine-
gar of a bad quality, ill distilled or ill saturated, over which
the depurating qualities of the charcoal had no influence>
several chemists have been unsuccessful.

From these considerations, and particularly from the sa-
tisfactory results obtained by the committee, they think
themselves warranted in concluding, that the authors of the
two memoirs would have done better by making known the
principle and the causes of the colouring of this salt, at the
same time that thev indicated the means of preventing and
removing them.

By following carefully the rules which they prescribe,
and by taking all the precautions which they point out,
we shall easily obtain, without having recourse to fusion,
an acetate of potash very white and perfectly saturated.
The society has therefore decreed a gold medal of the
value of 100 francs to each of the authors of the memoirs.

The author of the memoir first mentioned is M. Ber-
noully of Bale; and of the second, M, Fremy of Versailles.

VIII. Of the Influence of Solar and Lunar Attraction on
Clouds and Vapours, By Salem Harris, Esq,

To Mr. Tdloclu

Sir, In perusing the theory of the tides as originally laid
clown by Kepler, and subsequently improved upon by Sir
Isaac Newton, I was forcibly struck with an idea, that if
the attraction of the sun and moon (more particularly the
latter) is capable (as the ebb and flow of the sea appears to
have proved beyond dispute) of acting with sufficient
power upon that immense and ponderous mass the ocean,
to raise its waters on those parts which the revolutions
of the heavenly bodies alternately place in the focus of
their attraction ; its effects upon the clouds, the lighter and
exhaling particles, or comparatively speaking the steam of
those waters-, must be still greater; and sufficient to pro-
duce, in conjunction with or opposition to the wind, those
frequent and apparently uncertain changes which we.

hourly

AUr action on Clouds and Vapours. 59

hourly experience in the atmosphere. Impressed with this
idea, and not without some degree of wonder to find it, as
for as I could learn, unnoticed by the philosophical world,
I began when at school to form a journal of the weather;
noting at every observation the quarter of the wind, as well
as the moon's altitude and azimuth; and had the satisfac-
tion of finding my infantile speculation so well grounded,
that I observed the weather almost invariably thick or
rainy, when the wind and moon, being at or near the same
quarter, were acting in conjunction ; the latter drawing
the clouds, as I imagine, to her nearest point of the hori-
zon, from whence the former drives them over its surface;
and that it became proportionally clearer as their relative
change of situation enabled the wind to counterpoise the
moon's attraction, and prevent those vapours from collecting.
In the year 1800, a voyage across the Atlantic, and a
residence of some months at Havannah, enabled me to
extend my observations to the northern extremity of the
trade winds, as well as the climate of the torrid zone, both
on sea and land. I shall therefore extract the journal of
a few days in each of the situations wherein I have no-
ticed the weather; with a slight comment on the nature of
the country and the prevailing winds, or periodical change
of seasons, leaving your philosophical readers to compare
my statement with the idea that gave it birth.

Journal of the Weather at Wandsworth, near London.

Day of

the
Month.

Time

of

Day.

Morn
Even

Wind*

Moon's
Azimuth.

Moon's
Altitude or
Depression.

50° Depr.
23° Alt.

Observations.

Qct.27,

1800.

s.s.w.
s.

N.
S E. by S.

Very fine weather.
Cloudy and rainy.

28

Morn

Even

s.s.w.

S.SJL

N N.W.
S.E. by S.

14° Depr.
2;Jo Alt.

Fine weather.
Cloudy and rainy.

29

Morn

Even

Morn
Even

Morn

Even

Morn
Even

Morn

Even

Variab. fr.
S.E. to S.W.
S.W. by W.

N.W. by N.
S.E.

35° Depr.

24° Alt.

Fine weather.

Fair weather, but cloudy.

30

S.E. by E.
Ditto.

N.W.
S.E. by E.

26° Depr.
230 Alt.

Very fair, but rather cloudy
Very cloudy, but np rain.

SI

S. by W.

S.W.

N.W.

E.S.E.

N.W.bvW.

15° Depr.

24° Alt.

Raining a little,butappears

to be clearing off.
Very fine weather ; no elds.

Nov.

1

S. by E.

S.W.

4° Depr.
21° Alt.

Fine weather ; a few light
Ditto ditto. [clouds.

2

S.W.

S.E. by E.
strong.

W.N.W.
E. by N.

5° Alt.

17° Alt.

1

Fine weather, a few clouds

in the N.E. horizon.
Cloudy, with a little rain.

60

-

Of the Influence of Solar and Lunar

Journal of the I Feat her at Sea, letwecn Madeira and the Capt

Verd Islands,

Day oj

the
Month

Time

<>J
. »y.

Morn
Even

Wind.

Moon's

Azimuth.

Motu's
AllUnde or Observations.
Oppression.

Marcl
16,

1809.

< E S.E.
("nearly calm
S NiW. '
I very light.

( rath, string.
( moderate.

E. by S.
W. by N.

25° Ait
8" Depr.

Very cloudy : raming to wind-
ward.

Cloudy, but no rain.

17

Morn
Even

E. by S.
W. by S.

11° Alt.
19" Alt.

Very fine and serene.
Ditto ditto.

18

Morn
Even

S NW.
( moderate.
\ N.
( very light.

< N.N.W.
} nearly calm.
\ N.
? nearly calm.

E. by N.
W. by N.

8° Alt.
G° Alt.

Very fine and serene : a few
light clouds.

Fair ; but rather cloudy.

19

Morn
F.vcn

E. by N.

w.

0°

i'-M* Alt.
1

Very fine and serene,.
Ditto ditto.

£0

Morn
Even

5 N.

? nearly calm.

i s.w.

< nearly calm-

E.N.E. ! 8° Depr.

W.byN. ;37° Alt.
i

Very fine : a few light clouds to
windward.

Ditto ditto.

21

Morn
Even

S NW.
^ strong.
$ N.W.
1 fresh.

N.E by E.
W. by S.

1j° Depr.
.33° Alt.

Cloudy and rainy.

Fair; but cloudy in many parts
of the horizon, particularly
to windward, and slight fly-
ing showers occasionally*-.

22

Morn
Even

Morn
Even

( N.W. by W.
} strong.
\ N.N.W.
( rath.strong.

N.E. by E. J20° Depr.
W.byS. i58« Alt.

Very fine: a few clouds round
the horizon.

Very fine : a few light clouds.

23

J N.N.E.
I moderate.
j N.E.
( moderate.

N.E.
W.S.W.

:)4P Depr.
31° Alt.

Very cloudy; with some rain.

Very fine and serene: a few
light clouds.

24

Morn
Even

Mara

Even j

5 N.byW.
1 moderate.

J N.N.E.
\ moderate.

S N N.E.
\ moderate.
5 N.E.
1 moderate.

N.N.E.
W. by S.

12° Depr.
rs° Alt.

Very fair; but many light
clouds, particularly to wind-;
ward and as far as the east.

Very fine: light clouds in most
parts of the horizon.

N.E. by N.

In the

1

:8° Depr.
Zenith.

Very cloudy ; and a little rain i.

appears now to be clearing off".

Very fine : a few light clouds in

several parts of the horizon.

* Between the above two observation* (about half past three P.M.) there was
rather a heavy squall of rain v.-hh a strong breeze from the N.W.; the moon nearly
in the zeuith,' and most parts of ike horizon cioudy.

Attraction on Clouds and Vapours, 61

On the 16th, I was in sight of Madeira, and crossed the
tropic of Cancer on the £4th, in longitude 24° 30' west
of Greenwich; the ship's course being S. S.W. The for-
mer part is consequently on the verge of the trades ; as the
latter is of the torrid zone. At this season of the year
the winds are variable, but generally strong.

Journal of th Weather at Hcvannah.

Day of
the

Month

Sept.

10,

1809.

11

12

IS

Time
Day.

Morn
Even

Mi . n
Even

Morn
Even

Mora
Even

14

Morn
Even

16

Morn
Even

Morn
Even

Wind.

N. by W.

N.N.E.

5.E.
E.N.E.

S.W.

very light.
E.S.L.

S.E.
nearly calm

N.N.E.

E.S.E.
nearly calm.
N.

S. by E.

nearly calm.

S.S.E.

N. "
strong.

Moon's
Azimuth.

Maori's

4Uitude or
Depression.

E. by S.

21° Alt.

W.

10° Depr.

E.
W. by S.

7° Alt.
.0°

E. by S.

5° Dffpr.

W. by S.

8° A\t.

E.

2lo Depr.

w.s.w.

10° Alt.

E.

32° Depr.

S.W. by W.

31° Alt.

E. bv N.

42° Depr.

S.W.

:35° Alt.

E. by N.

o4° Depr.

S.S.W.

42° Alt.

Observations.

Very fine: a few light clouds

to leeward.
Fine : a few clouds to windwd*.

Fair; but very cloudy.
Very fine aud serene.

Very fine : a few clouds rising

to windward.
Very fair: some clouds to do.

Very fine; some clouds rising
in the eastern horizon.

Very fine: a few clouds near
the moon.

[At noon this day the ther-
mometer stood at 00°.]

Fine : some clouds
windward.

Ve." zinc and serene.

rising to

Very fine : light clouds rising

to windward.
Very fine and serene.

Very fine: some clouds to lee-
ward.

Very fine: some clouds towind-
ward.

Ilavannah is situated but a few miles south of the tropic
of Cancer, and^the land about it moderately high. It is
sheltered by the hills of the Cavannah from all winds be-
tween N.E. and E.S.E., and these are by far the most
prevalent. In the evening, however, it often shifts to the
north, or even a point or two to the westward. At this
season of the year the weather is intensely hot, with f re*
quent and violent storms of rain and thunder, which usually
take place between the houis of two and six in the after-
noon.

Jjurnal

62 Of the Influence of Solar and Lunar

Journal of the Weather let ween Bermuda and the Western Isles.

Day of
the

Mn.'ilh.

Time

<>/
Day.

livid.

slzimutii.

M ami's
Altitude™
Depression

Olkrvations.

i C

-c. .52 "3
•>'£ s

Nov.

25,

1809.

Morn
Even

J E.S.E.
( very strong.
\ E.S.E.
\ light.

W. by N.

E.N.E.

17* Alt.
8° Dcp.

Fine: but rather cloudy
in many parts of the
horizon.

Cloudy, with a lit. rain.

G7°
6S°

26

Morn
Even

f E. byS.
\ £.ttong.
S N.E.
\ strong.

W. 25° Alt.
N.E. by E. 18° Dep.

Very fine and serene.
Cloudy, with small rain.

67°
G9°

27

Morn
Even

f N.K.
| blows hard.
j N.N.E.
1 a heavy gale

W. by S.
N.E.

34" Alt.
27° Dep.

Hazy weather.

Very thick and cloudy,
with small rain.

66°
66° 30

28

Morn
Even

f E.N.E.
1 strong.
\ E.N.E.
£ strong.

w.s.w.

N.E.

41° Alt.
37° Dep.

Very fine i a few clouds

in the horizon.
Cloudy, with occasional

showers.

67°
69°

29

Morn
Even

J N.E. by E.
1 very strong.

S.W. by W-

N.N.E.

47° Alt.
46° Dep.

Thick hazy weather,

' with some small rain
at intervals ; appears
now to be cl earing off.

Thick and cloudy, with
small rain.

[Between the above ob-
servations, hazy wea-
ther with occasional
showers; the wind
light and variable.]

67°
6t»

SO

Morn
Even

( moderate.
| N.E. by E.
"|_ moderate.

S.W.
N. ;

45° Alt.
51° Dep.

Fine : a few clouds,
which are clearing off.

Very fine : a few clouds
to windward.

[Much rain between 1 1
P.M. of the 29th and
1 A.M. of this day:
the wind and moon be-
ing nearly in the same
poin t (E. by N.) and the
latter on the horizon.

67° 30*

68°

Dec.

1

Morn
Even

J N.N.E.
^ moderate.

f N. byE.
\ moderate.

s.s.w.

N.

53° Alt.
55° Dep.

Very fair, but rather
cloudy, particularly-
near the moon.

Fair; but cloudy in most
parts of the horizon,
particularly from N
to W.

S7°
67° SO'

In this part of the globe, more particularly during the
autumnal and winter months, the wind is usually strong;

often

Attraction on Clouds and Vapours. 63

often increasing to a gale; the heaviest usually blows from
the north and north-west. These observations were made
between the 35th and tfi\i degree of north latitude, and
44° and 30° longitude west of Greenwich: the ship's
course being E. by N.

There are certainly many places, in which a particular
wind almost invariably produces rain ; from the interven-
tion of a chain of hills, or even a single mountain that im-
pedes the regular course of the clouds, when moving in a
certain direction; and breaks them over the valleys below.
Or, the wind may be either sufficiently strong to over-
power the moon's attraction, or -so light as to afford no
assistance in spreading the clouds which have been col-
lected on or below the horizon, and thus produce an ef-
fect upon the weather contrary to what might have been
expected from the relative situation of the impelling powers ;
a circumstance which, though very material, did not
strike me when I began my observations ; and the ve-
locity of the wind is consequently unnoticed in the first
part of my journal. Our atmosphere may contain at times
so little vapour, as to be incapable of producing rain, al-
though the moon and wind were acting ever so much in
unison; but this can always be ascertained by the state of
the barometer. When also the moon's altitude or de-
pression is so great as to place her nearly in the zenith, or
the nadir, her attraction can of course avail but little,
either in assisting or counteracting the effect of the wind
from whatever point it may happen to blow: its power, in
short, must diminish in proportion as her distance from
the horizon increases.

I do not pretend to improve, much less to controvert, the
theories of those many learned and scientific characters
who have written upon the nature and variation of the
atmosphere; for my knowledge in every branch of philo-
sophy is very slight; but I cannot help thinking, that a
little attention to the subject which I have noticed, would
frequently assist an observer of the weather, in foreseeing
with additional certainty an approaching change; and I
offer these remarks to the public, with no other view than
the possibility of their being investigated, by those who
possess the knowledge and leisure requisite in philosophical
studies, to the advancement of science, as well as the bene-
fit of those professions, in which a dependence is placed
upon the atmosphere. I remain, sir,

Your respectful humble servant,

Richmond Green, July 10,1810. JSALEM HARRIS.

IX. On

[ 64 ]

IX. On -Crystallography. By M. Hauy. Translated
from the last Paris Edition of his Traite de Mineralogie.

[Continued from vol.xxxv. p. 4GO.]
TABLE OF THE CRYSTALLINE FORMS.

I. Substances tv hick have a conunon primitive form } with

the same dimensions.

I. CUBE.

Names of the Substances. Form of the integrant Molecule.

Jl$o rated magnesia Cube

Muriated soda . . ., Ditto

.Amphigene Irregular tetrahedron

Analcime Cube

Sulphurated lead Ditto

Sulphurated iron Ditto

Oxidated tin Ditto

Gray cobalt Ditto

Calcareous scheclin Regular tetrahedron.

2. REGULAR OCTAHEDRON.

Filiated lime Regular tetrahedron

Muriated ammonia Ditto

Sulphated alumine Ditto

Spinelle Ditto

Pleonaste Ditto

Diamond Ditto

Red oxidated copper Ditto :

Oxidulated iron Ditto

Native bismuth Ditto

Native antimony Ditto

3. REGULAR TETRAHEDRON.

Pyritous copper Regular tetrahedron

Gray copper Ditto.

4. RHOMBOIDAL DODECAHEDRON.

Garnet , Tetrahedron with isosceles

triangles equal and similar
Sulphurated zinc Ditto.

II. Substances the primitive forms of which only are of
the same kind^ with dimensions respectively peculiar to
each.

) . RHOMBOID.

* With obtuse summits.

Carbonated lime- Rhomboid

Tourmaline

On Crystallography. 6*5

Names of the Substances. Form of the integrant Molecule.

Tourmaline Irregular tetrahedron

Chabasie Rhomboidal

Dioptase Ditto

Sulphurated antimoniated

silver Rhomboidal.

** With acute summits.

Corundum Rhomboidal

Oligistous iron Ditto

Sulphurated iron Ditto.

2. OCTAHEDRON.

* Pyramids with square bases.

Alkaline filiated alumine . . Irregular tetrahedron

Zircon Ditto

Harmotome Ditto

Anatase Ditto

Molybdated lead ......... Ditto

Mellite Ditto.

** Pyramids with rectangular bases.

Nitrated potash Irregular tetrahedron

Carbonated lead Ditto

Sulphated lead Ditto

Oxidated zinc Ditto.

*** Pyramids with rhombic bases.

Sulphur Irregular tetrahedron

Red sulphurated arsenic . . . Irregular tetrahedron.
Blue carbonated copper . . . Ditto.

3. TETRAHEDRAL PRISM.
1. STRAIGHT PRISM.

* With square bases,

Sulphated magnesia Isosceles-rectangle-triangular

prism

Idocrase Ditto

Meionite ♦ . . . . Prism with square bases

Wernerite Ditto

Mesotype Isosceles-rectangle, triangular

prism
Chromated lead Ditto

Vol. 36. No. 147. July 1810. E Oxidated

00 On Crystallography.

Names of the Substances. Form of the integrant Molecule.

Oxidated uranium Prism with square bases

Oxidated titanium Isosceles-reciangle-triangular

prism.

•* With rectangular bases.

Cymophane Prism with rectangular basest

Euclase . Ditto

Peridot Ditto

Prehnite Ditto

Stilbite Diito

Ferruginated scheelin .... Ditto

*** With rhombic bases.

Sulphated barytes Scalene - rectangle- triangular

prism

Sulphated strontiari Ditto

Topaz Prism with rhombic bases

Staurotide Isosceles -rectangle-triangular

prism

Made .......... Uncertain

Mica , . . . . . Prism with rhombic bases*

Talc Ditto

Arsenical iron Ditto

Sulphurated molybdenum . Ditto
Siliceo-calcareous titanium Ditto.

***# With oblique-angled parallelogram bases.

Sulphated lime Prism with oblique - angled

parallelogram bases

Epidote Prism with oblique-angled

parallelogram bases
Axinite Ditto.

2. OBLiaUE PRISM.

* With rectangled bases.

Borated soda Prism with rectangled bases*

** With rhombic bases*

Amphibole Prism with rhombic bases

Actinote Ditto

Pyroxene Oblique triangular prism

Grammatite Prism with rhombic bases.

*** With oblique-angled parallelogram bases.

Feldspar Prism with oblique angled

parallelogram bases

Disthene

On Crystallography, 67

Names of the Substances. Form of the integrant Molecule.

t)isthene ..."". Prism with oblique angled

parallelogram bases
Sulphated copper Ditto.

4. REGULAR HEXAHEDRAL PRISM.

Phosphated lime Equilateral triangular prism

Telesie Ditto

Emerald \ ....... Ditto

Nepheline Ditto

Pycnite Ditto

Dipyre ......... Ditto

Sulphurated mercury Ditto.

5. PYRAMIDAL DODECAHEDRON.

Quartz Irregular tetrahedron

Phosphated lime Ditto.

III. Forms which are found to be secondary in different

species.

1. CUBE.

Names of the Substances. Primitive Forms.

Filiated lime Regular octahedron

Native bismuth Ditto.

2. REGULAR OCTAHEDRON.

Muriated soda Cube

♦Sulphurated lead Ditto

Sulphurated iron Ditto

Gray cobalt * . . . Ditto.

3. REGULAR HEXAHEDRAL PRISM*

Carbonated lime Obtuse rhomboid

Corundum Acute rhomboid

Mica Straight prism with rhombic'

bases
Sulphurated antimoniated

silver Obtuse rhomboid

Phosphated lead ......... Pyramidal dodecahedron

Sulphurated molybdenum . Straight prism with rhombic

bases.

4. RHOMBOIDAL DODECAHEDRON.

Filiated lime Regular octahedron

Oxidulated iron • Ditto.

E 9, 5. SOLID

68 On Crystallography.

5. SOLID WITH 24 EQUAL AND SIMILAR TRAPEZOIDS.
Names of the Substances. Primitive Forms.

Muriated ammonia Regular octahedron

Garnet . Rhomboidal dodecahedron

Amphigene Cube

Analcime Ditto

Sulphurated iron Ditto,

Explanation of the plan which has been adopted in the de-
scriptions of the different species of minerals.

After having given the sytfonymy of (he best known
authors, we have successively presented the essential cha-
racter of the substance, and the physical, geometrical, and
chemical characters, the assemblage of which forms the
specific character.

We have excluded from this character every thing con-
nected with fugitive accidents, such as colours, when they
are owing to a principle which is only interposed in the
substance.

In the detail of the geometrical characters, care has been
taken to indicate not only the direction of the natural joints,
Jbut also the greater or less facility of obtaining them, their
difference of neatness in one and the same crystal, and
those, in short, whose positions are only presumed. In
addition to this, we haVe made known, in a note, the re-
spective dimensions of the molecule, and all that may serve
as data for applying the theoretical calculus to the laws of
decrements upon which the secondary forms depend.

After the indication of the chemical characters, we have
"given the result of the analyses of the substance which
seem to have merited most confidence.

The table of varieties, which follows the characters, is
generally divided into two sections, one of which contains
the descriptions of the forms, and the other refers to the
accidents of lights. The forms are either determinable,
i.e. susceptible of being described geometrically, from the
number, the disposition and the mutual incidences of their
faces, or indeterminable, i. e. produced by a confused or
precipitated crystallization, so that geometry cannot de-
scribe them, and we can at most indicate the vague rela-
tions which exist between them and known objects ; as
when we say of a mineral that it is cylindrical, globular,
granular, &c. and the last term of this kind of degradation
of forms is expressed by the word amorphous, which de-
signates a substance in masses of a certain volume com-
pletely irregular. The

On Crystallography, 69

The description of every determinable variety presents
successively the name which it bears, conformably to the
principles of the method of nomenclature which has been
above explained, the indication of its representative sign,
that of its figure, its synonymy, according to Korae de
1'Isle or other crystallographers; and lastly, the measure-
ments of its principal angles. When the structure of the
variety is complex, we add to its description explanations
proper for better understanding the results of the laws upon
which it depends.

The indications relative to colour and to transparency
compose the second section, under the title of Effects of
light*. It is proper to remark on this subject, that any-
given form may offer successively all the varieties of co-
lour and transparency, and that, in return, evary colour
and every degree of transparency may be met with in every
kind of form. But it is unnecessary to overload the me-
thod with all these combinations. It is sufficient, if it
presents a method of indicating that which exists in any
given variety, to describe' this variety completely. Thus
the table of the characters of telesie contains implicitly all
the following combinations : primitive limpid telesie; unit
tary red transparent telesie ; amorphous translucid telesie.

When the name which we have adopted for ori£ species
of mineral has been applied to different species, from a de-
lusive resemblance, such as colour, we indicate these doable
applications in a particular table placed at the end of that
of the varieties ; and I hope I shall be applauded for the
tedious task whrch I have entered upon, in order to clear
up the confusion which arose from these communications
of one and the same name to substances so ill adapted to
be associated with each other.

Each article is terminated by annotations relative to the
situation of the substanees'in the ground, to the researches
which have made us acquainted with them, to its physical
properties, its uses in the arts, medicine, &c. I have even
thought it right to present most of these objects more in
detail than has been generally done, so as to avoid the
dryness of too concise indications, without however giving
myself up to a multiplicity of details which would appear
to be misplaced in a treatise upon mineralogy.

[To be continued.]

* We have placed the word limpid at the head of effects of colours, be-
cause it seemed natural to commence here by the privation of character,
jince it indicates that the substance is in the greatest possible state of purity.

E3 X. Pro-

C 70 )

X. Proceedings of Learned Societies,

ROYAL SOCIETY.

J une 28, The President in the chair. The conclusion of
M De l'Isle's paper on the poison of the Lohan upas and
a.ntea was read. The emetic power of this poison sug*
gested to the author the propriety of making some experi-
ments with other emetics, hy {meeting them into wounds
and blood-vessels in the same manner as he did the upas.
Ipecacuanha and tartar emetic were injected, and both pro-
duced very violent eftects, particularly the latter; but they
were not so destructive to animal life as the upas. On
dissecting the bodies of the animals killed by injecting this
poison, and comparing them with the effects of common
emetics, he was led to conclude that the upas does not kill
by any specific action on the nerves, but that, by acting on
the blood only, it is so instantaneously destructive to ani-
mal life.

A paper from Mr. Good was read, describing the nature
of the horny concretions which appeared all over the skin
S>f a heifer exhibited in London last year, The head, neck,
and shoulders of this animal were thickly covered with
little horns of various length and thickness, some of them
nearly three inches long. It appears that these horns were
chiefly composed of calcareous matter, and that one-fourth
of them was of an animal nature.

July 5, Dr. Wollaston read a paper on a peculiar species
of urinary calculus, which he called cystic oxide, only two
specimens of which he has been able to procure. The
cystic oxide dissolves in solutions of all the alkalies, but
not in saturated carbonate of ammonia. Dr. W. also took
occasion to correct some essential errors in his paper on
calculi, which appeared in the Philosophical Transactions
for 1 797 ; subsequent experience having convinced him that
phosphate of lime, and phosphate of magnesia rarely or
never exist together in the same calculi1.?.

A paper on muriatic acid, by Mr. Davy, was read. The
object of Mr. Davy's paper was to detail some new facts
respecting the muriatic acid. Finding that charcoal, though
janited to whiteness, will not burn or decompose oxy-
jnuriatic acid gas, he was hd to institute experiments to
determine whether oxygen could be procured from it by
anv means': and the results of his inquiries are, that there.
is no proof whatever of its containing that substance.
Muriatic acid gas may be decomposed into oxymuriatic

ack$

Imperial Society of Natural History of Moscow. 7*

acid and hydrogen ; and recomposed from these bodies.
In ail cases in which oxygen gas is procured from oxy-
muriatic acid gas, water is present : and the oxygen is fur-
nished by the water; and hydrogen is always combined
with the oxymuriatic acid gas; so that, as inflammable
bodies decompose water by attracting oxygen, so oxymu-
riatic acid decomposes it by attracting hydrogen. Mr. Davy
has detailed some experiments which render it probable
that the body called bvperoxymuriatic acid is in fact the
simple basis of the muriatic compounds, and that it forms
oxymuriatic acid by uniting to hydrogen, and common
muriatic acid gas by uniting to more hydrogen.

In attempting to decompose oxymuriatic acid gas by the
combustion of phosphorus and the action of ammonia,
Mr. Davy discovered a very singular compound; which,
though composed of oxymuriatic acid and ammonia with
a little phosphorus, is neither fusible, volatile, nor decom-
posable at a while heat ; neither soluble in acid nor alkaline
menstrua; and possessed of no taste or smell.

Mr. Davy has detailed nine modes of decomposing
common salt, founded upon these new facts, and has,
formed nine deductions from them respecting the com-
position of chemical agents in general.

A paper on pus, by Dr. Pearson, was read. Previously
to the author's observations and experiments, a brief his-
torical account was given of what has been already done
on the subject. The conclusions among many others are ;
That the pus consists essentially of three differentsubstances,
viz. An opake animal oxide, seemingly already self- coagu-
lated; matter analogous to the coagulablc lymph of the
blood, but in a different state of aggregation. 2. Innumerable
spherical particles, seen with the microscope, separable by
chemical agents from the other parts. 3. A limpid co-
agulable liquid, in many properties similar to the serum of
blood. The saline impregnations are the same as those of
serum of blood aud expectorated matter, especially mu-
riate of soda, neutralized potash, and the phosphates of
lime. Various other substances are frequently found in
pus, which are considered to be accidental, and depend upon
different diseases.

The Society theu adjourned till Thursday the 8th of
November,.

IMPERIAL SGCPETY OF NATURAL HISTORY OF MOSCOW.

M. Fischer, president of this' society, has published the
following short account of their labours for the last four

£ 4 years.

72 Imperial Society of Natural History of Moscow*

years. This sketch is arranged under the following heads :
I. Labours and Undertakings of the Society. II. Mis-
cellanies. ] II. Promotions and Rewards. IV. Necrology.
V. Literary Novelties. VT. Minutes of the Society, and
Report of the Presents made to the Society and to the Mu-
seum of the Imperial University. The following are the
contents of the first branch of their labours.

Journey to Siberia undertaken at the expense of the Society,
— This expedition set out on the 9th of February 1SOQ. and
is to last three years. It is composed of Professor Tauber,
who is known from his description of the valley of Flatten
in Saxony; M.James Mohr, known from his travels in
Germany, France, England, and Sweden; and M, Helm,
botanist and chemist, known by his description of several
new plants, and by several analyses : this is his second visit
to Siberia. These gentlemen are accompanied by two pu-
pils, Messrs. KotororFand Leslivsky, and they are provided
with every necessary, such as books, charts, instruments,
and a chemical laboratory. They were to be occupied the
iirst year with the Ouxal chain of mountains; the second,
with that of the Altai ; the third, with the mountains of
the Daourie; and, if circumstances will permit them, they
will also visit Kamschatka. The profound erudition and
zeal of the above gentlemen afford reason to hope for-
some important discoveries. They are also accompanied
by a draftsman, and by a person who is acquainted with
the art of stuffing and preserving animals.

Decription of the Government of Moscow. — His Im-
perial Majesty having given five thousand roubles to be
expended in examining the immense district which goes
by this name, the professors of Moscow have recently
visited several parts of the country with this view. The
following is an account of what has been already done:
Some astronomical and trigonometrical observations have
been repeated at Moscow, and in some districts of the go-
vernment, such as Svenigorod berea, Moja;sk, Riotisa, by
professors Goldbach and Panthner, attached to the reposi-
tory for charts at St. Petersburgh. The latter has also
established, at the expense of the society, barometers and
thermometers at the above places, in order t© obtain some
useful observations.

M. Fischer undertook the natural history department :
he was accompanied in his excursion by M. Droucinine,
seerclary to the society; and by M. Gorke, one. of the
pupils at the university of Moscow. From the lateness

of

Imperial Society of Natural History of Moscow. 73

of the season they procured but few plants or insects, but
they were more fortunate in their mineralogical pursuits.
Petrifactions of all. kinds, several mineral springs rich in
iron and carbonic acid, a good clay for earthenware, La-
brador stone, garnets in granite and in gneus, granatite
in gneus, and a new earthy substance, were procured by
them. This new substance is of a very fine lavender blue,
and is found in veins several lines thick between layers of
cimolitc, which in some places forms the transition to a
true mountain cork. Sometimes it is found on round
masses of flint, sometimes fossil shells are found in it, and
pectinitcs which are wholly black and changed into flint.
This substance contains, according to the analyses of
Messrs. Helm and Muller, lime, alumine, and phosphoric
acid. It forms, therefore, a new species adjoining the
Apatite, and it has been designated by the name of Katof-
kite, from the place where M. Fischer resides.

Mr. Davy's experiments. — M. Jacquin in a letter to
M. Fischer informs him, that in concert with his friends
the director Schreibers, colonel Tihursky, and M. JBremser,
he repeated the recent experiments of Mr. Davy with suc-
cess. They generally made use of a battery with vertical
piles composed of 1300 pairs of disks, which were generally
three inches in diameter, and formed together 70 square
feet of surface in contact: — the experiment succeeded how-
ever with 300 pairs of disks, and it was even perceptible
with 70 pairs. One of the processes adopted by the above
gentlemen seems to be somewhat novel : they placed in
a wine glass a small piece of alkali moistened in the air, on
a small plate of platina which communicates with the hy-
drogen pole, and which was entirely covered with rectified
petroleum. Finally, they placed on the alkali a thin plate
of platina, <md pressed it with a metallic rod communicating
with the oxygen pole. The effects being remarked, bub-
bles of air were extricated as in the first experiment;
sometimes there were trifling detonations ; and sometime
afterwards they found the whole of the inferior surface of
the alkali strewed with small scales having a metallic ap-
pearance like those which are seen floating in the petroleum.
This preparation is very beautiful, particularly when placed
in the microscope. It is not combined easilv wiih mer-
cury ; for a globule adhering to the point of the brass wire,
when plunged in mercury, was not detached, and after-
wards detonated in water as before.

In the experiment last described, the place of the platina
may be supplied by a flat piece of charcoal. The diamond

and

74- Imperial Society of Natural History of Moscow.

and sulphur arc not conductors of the electric fluid, and,
produce no effect. The experiment does not succeed
better in vacuo than in the open air. u What is this sub-
stance (M. Fischer asks) which resembles a metal ? Is
it the alkali reduced, or one of its constituent parts, which
feeing combined with oxygen represents it, as Mr. Davy
seems to think? or, Is it hydruret of potash? But whence
this metallic appearance r"

Miscellanies. — Their majesties the Emperor Alexander I.
and the King of Prussia have examined with great interest
the skeleton of the mammoth brought from the shores of
the Lena by M. Adams *".

M. Tilesius, associate of the academy, well known for
his talent at painting objects in natural history, has pre-
pared 40 folio drawings of the mammoth. His observa-
tions do not seem to coincide entirely with those of
Cuvier.

The meteorological observations from Moscow prove
that the cold was greatest in the night between the 1 ] th
and 12th of January. Dr. Rehman froze mercury in a
saucer exposed to the air. Count Bontourline observed
that the mercury in three of his thermometers was frozen,
and sunk into the bowl. But in a thermometer which
was not frozen, he found that from six in the morning to
six in the evening, on the 12th of January, the cold was at
35° of Reaumur. M. Roger, of Troitsk, observed it at 34
degrees before the mercury was frozen.

The botanist Frederick Fischer, and M. Langsdorff asso-
ciate of the academy, who accompanied Krusenstern in his
voyage round the world, are occupied with a work on the
Ferns. They have prepared drawings of several new species.

M. Fischer, the professor and director of the academy, is
collecting materials for a comparative craniognosy. An
accurate knowledge, of the cranium, as one of the chief
organs of animal organization, will fill up an important
chasm in comparative anatomy. The craniology of Dr.
Gall will only be made use of in order to demonstrate the
influence of the brain on the form of the excavations of the
skull. It will appear in Latin and French, accompanied
with engravings.

M. Mohs has made a mineralogical excursion through
Carinthia, Carniola, &c. He has been particularly occu-
pied with the situation of the lead mines at Villach.

The Imperial Academy of Petersburgh proposed a prize

See Phi!. Mag. vol xxix. p. 141,

of

Notices respecting New Books* — Electric Column. 7 J

»f 100 ducats for the best memoir on the following subject :
*' Give an easy method for ascertaining, independent of all
knowledge of botany, poisonous plants in an indubitable
manner. " Three memoirs were consequently given in;
but the prize has not been awarded to either.

A similar prize has been offered for the best " chrono-
logy of the Byzantine authors from the foundation or the
cov of Constantinople to its conquest by the Turks, ' The
memoirs on the above subject must be transmitted to St.
fetersburgh on or before the 1st of July 1811.

XI. Notices respecting New Books.

*■

IE Medical Society of London have in the press a vo-
lume of memoirs, containing several valuable communica-
tions, in medical and surgical science, from eminent resi-
dent and corresponding members of the society. The title
of the volume vvijl be " Transactions of the Medical Society
ot London, Vol. I. Part I." and it will be accompanied by
engravings. Fart 11 will appear in a few months after-
wajrcUj the society having come to the determination of
giving publicity to the^r transactions more frequently than
heretofore*

XI I. Intelligence and Miscellaneous Articles,

PE J,UC\S EL' CTRIC COLUMN,

Jo Mr. Tillock.

NJuIy 23*1, 1810.
otwithstandixg the changes which have hap-
pened in the. state of the atmosphere, the small bells, which
are in communication with De Luc's electric column, have
pontmued to ring without ceasing, as far as my observa-
tions have gone, from the 25th ot March to this day. Al-
though we have of late had heavy rain accompanied with
thunder and lightning, we have not had any very damp
weather, which 1 imagine is the most likely to stop the mo»
tion ol the small clapper, by depositing moisture on the
insulating parts of the apparatus. — If you, or any of vour
readers, are acquainted With a method of preparing varnish
of a better insulating power than those varnishes mentioned
in Cavallo's Treatise on Electricity, I shall be glad to have
it communicated to me, and others who are interesting
(bemstjves in making experiments with this new column.

1 wish

76 The Opulent Blind* — Artificial Cold,

' I wish here to correct a mistake which I made in the ac-
count of the electric column printed in your Magazine for
March last. I there have miscalled the ends of the co-
lumn : that which I have named the zinc end should have
been named the silver end, and the contrary. So that the
effects on the electrometer of the coated jar were, respect-
ing the plus and minus states, just what might have been
imagined they would be. The mistake arose owing to the
silver and paper being connected together; for, had the
two metals been united, and the paper separate, the instru-
ment would then have re?embled more the usual construc-
tion of a Galvanic trough ; and I should not, I imagine,
have been led into any error respecting the names of the
ends or poles of it. I remain, &c.

B. M. Forster.

THE OPULENT BLIND.

The plan to which we alluded in our last has been since
published in a prospectus. For the purpose of this Tiumane
institution a convenient house has been taken at No. 5,
Prospect Place, Lambeth. The prospectus states : That
under the patronage of his royal higness the Duke of Sus-
sex, a seminary is to be opened for the tuition of blind sub-
jects of the higher classes of society, where they may be
taught reading, writing, the means of corresponding with
distant friends, music, geography, the belles lettrcs, lan-
guages, the rudiments of the sciences generally, and such
a familiar acquaintance with prevailing accomplishments,
as will enable the blind of both sexes to partake of the in-
nocent amusements of societv, including draughts, back-
gammon, chess, cards, dancing^ &c. Among other addi-
tions to the plan of M. Haiiy, who succeeded in a similar
attempt at Paris before the revolution, and on whose mo-
del the institution professes to be formed, it adopts the idea
of its pupils deriving, from a constant and consoling illus-
tration of the Gospels, those dispositions to habitual cheer-
fulness and content which they are so eminently calculated
to excite when contemplated properly.

ARTIFICIAL COLD.

Professor Leslie, of Edinburgh, in following out a
series of experiments on the relations of air and moisture,
has within these few weeks been led to a very singular and
important discovery. Without any expenditure of male-
rials, he can, by means of a simple apparatus, in which the
action of certain chemical powers is combined, freeze a

mass

Supposed New Earth. — Cranlology. 77

mass of water, and keep it for an indefinite length of time
in the state of ice. In the space of an hour he has, on a
small scale, formed a cake of ice 6 inches in diameter, and
three quarters of an inch thick. With very little trouble
he can produce a permanent cold of 90 degrees of Fahreu-
.heit below the temperature of the air, and might easily push
it to 100 or even 110. The professor is now engaged in
prosecuting these fruitful researches, and will soon, we
hope, favour the public with an account of his process, and
of the chief results.

SUPPOSED NKW EARTH.

M. Vinterl, of Pest in Hungary, has lately sent to the
French Institute several specimens of an earth which he
conceived to he new, and to which he gave the name of
Andronia. A committee of the Institute, consisting of
Messrs. Fourcroy, Guyton Morvcau, Berthollet, and Vau-
quelin, have analysed this substance, and have determined
that it is merely a compound of silex, lime, alumine, potash,
and iron;

ckaniology.

The following observations have been published in the
foreign journals on the system of craniology by M. Gall.

1. The Italian poet Dolce, who died in 1568, in his dia-
logue on the means of preserving and strengthening the
memory, alludes to a head which is represented at page 8
of the Venice editions of 1562 and 1566, the cranium of
which is divided and figured according to M. Gall's sy-
stem; and under this wood-cut we read the following in-
scription: " In questa tu vedi ove e il senso commune,
ove la fantasia, la cogitativa, la imaginativa, la stimulativa,
la memorativa : ed anco 1'odorato e il gusto. "

2. The grand chancellor of Denmark, Schumacher,
count Griffenfield, who died in 1699, must have practised
cranioscopy with success, if we may credit M. Wedel
Simonson, the author of a dissertation read before the me-
dical society of Copenhagen. The same gentleman (M.
Schumacher) maintained a medical disputation in 1650,
De nervis ; Bartholin being then president of the above so-
ciety.

3. Frenair (a French author) says in his biography or
Laurence Sterne, who died in 1768, and which was pre-
fixed to the French translation of Sterne's works, iC that an
eminent surgeon had dissected the brain of Laurjnce
Sterne, under the persuasion that he would find something
extraordinary in its configuration."

4.,Swedenborg, wh6 diecf in 1774, taught that good or

' - - bad

78 List of Patents for new Inventions,

bad qualities had an influence on the form of the cra-»
nium.

5. The principal theorem of M. Gall, that the brain im-
presses on the cranium its different forms, is also to be
found in the " Fragmens Phyyiognomiqiies" of Lavater,
Leipsic, 1775 — 1778.

A German traveller has recently discovered in the neigh-
bourhood of the Red Sea the ruins of the ancient city of
Dscherraseh, probably the Gerusa of antiquity. He found
the remains of several public edifices, two amphitheatres,
several palaces, a temple, &c.

DEATH.

Geology and natural history have lately sustained a se-
vere loss by the premature death of Mr. William Martin,
of Macclesfield, Cheshire, a member of the Geological So-
ciety of London, and author of a most useful work, " Out-
lines of an Attempt to establish a Knowledge of extraneous
Fossils on scientific Principles," in octavo ; -and also of
1' Petrificata Derbiensia, or Figures and Descriptions of Pe-
trifactions collected in Derbyshire,'* in 4to. with coloured
plates; of which 52 are contained in the 1st volume pub-
lished less than a year before his death. We are truly con-
cerned to learn that Mr. Martin has left a wife and young
family without means of support ; the profession he fol-
low ed, that of a drawing-master, as commonly happens
in country places, not having proved very lucrative. We
should rejoice to hear that any considerable progress has
been made by Mr. M. towards a second volume of the
above highlv interesting and useful work, and that some
means were devised by the friends of geological science to
alleviate the situation or' his widow and orphan children.

LIST OF PATENTS FOR NEW INVENTIONS.

To the Rev. Henry Liston, of Eccjesmachen, in Scot-
land, and Charles B rough ton, of Edinburgh, writer to
the signet, for improvements in the construction of or-
gans.— July 3, 1810.

To Samuel Hill, of Serle-street, London, Esq., for a
method of joining stone pipes in a more effectual manner
than has been before discovered. — July 3.

To James Hall, of Walthamstow, for a method of
manufacturing a material from the twigs or branches of
broom, mallows, and rushes, and other shrubs or plants of
the like species, to be used instead of flax or hemp \ and
for the same purposes for which flax and hemp zx% now
used. — Jnlv 3. T%

List of Patents for netv Inventions. .79

To John Kent, of Southampton, architect, for certain
improvements in the method of making artificial stone. —
July 3.

To Robert Howden, of Providence- row, Finsbury-
square, baker, for an improved method of extracting foul
air out of ships, whereby a constant succession of fresh
air will be introduced ; and at the same lime moderating;
the degree of heat according to the climate. And also of
extracting the foul air from mines and pits of every de-
scription, and of regulating the degree of heat, and of
giving heat and a constant succession of fresh air to
houses in general — July 3.

To William Shakespear, of Birmingham, and Thomas
Osier the younger, of the same place, for an improved
method, or methods, of manufacturing glass or paste
drops for chandeliers, lamps, and lustres. — July 5.

To Richard Vartey, of Cheadle Mosley, in the county of
Chester, for certain new additions to and improvements
upon the machinery now in use for the roving, spinning,
doubling, and twisting, of cotton, silk, flax, wool, mo-
hair, and other materials used for the manufacture of twist,
thread, or other kind of yarn. — July 7-

To George Hall, of the Strand, goldsmith, for certain
improvements in the art of working and making spoons,
forks, and such other articles of gold, silver, or other
metals, as usually are or may be stamped or struck by
means of seats and punches, or dies of any kind or de-
scription i and likewise in the tools or instruments to be
used in carrying the said improvements into effect and prac-
tice.— July 18

To Ralph Wedgwood, of Oxford- street, for his new
character for language, numbers, and music, and the me-
thods of applying the same.— July 18.

To George Stebbing, of Portsmouth, mathematical in-
strument maker, for certain improvements on the action
and other parts of sea and land compasses. — July 18.

To Benjamin Agerday, of Handsworth, Staffordshire,
for improvements in the construction of a toast-stand, (for
the purpose of holding a plate before the fire,) a hearth-
brush or dust brush, and toasting fork, and occasionally
in combining or uniting the said brush and toasting fork in
one utensil or article — July 18.

METRO-

80

Meteorology,

METEOROLOGICAL TABLE,

By Mr. Carey, of the Strand,
For July 1810.

Days of
Month.

Thermometer.

u ~

9 o

CO

5 4^

sJ bfl

Height of

the Baroro,

Inches.

gjT2

Oil in •a..

Weather.

June 27
28
29
30

July 1

2

3

4

5

6

7

8

9

10

II

12

13

14

15

16

17

18

19

20

21

22

23

24

2-5

26

57

59

66

60

64

60

60

61

60

64

65

67

60

66

65

60

63

66

64

66

56

52

56

56

52

53

57

58

59

66

64°

69

68

72

74

74

66

56

67

70

74

60

70

69

75

70

71

69

69

68

64

65

66

65

63

64

70

70

73

63

59(

66

56

63

66

64

55

54

64

62

64

55

58

64

62

60

64

57

56

55

52

55

52

54

52

57

54

57

64

60

29*9@
'99
•99

30-10
•07

29*81
•45
•36
•79
•98
•99
•80
•88
'75
•54
'60
'56
'75
•80
•93
'55
•70
•80
•80
•94

30*11
•16
•14

29*96
•64

30
50
10
60
65
70

0

0
51
62
65
10
52
35
66
49
68

0
36
48
33
44
62
60
45
46
70
53
40

0

Fair

Fair

Showery

Fair

Fair

Fair

Rain

Showery

Showery

Fair

Fair

Rain

Fair

Fair

Stormy

Showery

Showery

Showers with

Ditto [thunder

Fair

Cloudy

Fair

Fair

Fair

Cloudy

Fair

Fair

Fair

Showers

Rain

N. B. The Barometer's height is taken at one o'clock.

L 81 ]

XlV. On Pendulums. By Ez* Walker, Esq*

JL he mechanism of pendulums is a subject which has of
late years attracted much attention ; but whether any real
improvements have been made since the days or" Harrison,
is a question on which there are various opinions. Rods
of' zinc, pewter, lead, and other soft metals have been
substituted for those of brass, to reduce the gridiron pen*-
dulum to a more simple form : but it has been found by
experience that some of those soft metals, when under the
pressure of the weight of the lens, do hot long retain ftife
same power of expansion and contraction.

The late Mr. James Bullock, a very ingenious clock-
maker, and a man of much experience, told me, that brass
and steel were the only metals he could rely on, in the
construction of compound pendulums.

The gridiron pendulum is constructed on the supposition,
that it is kept invariably of the same length by rods of
different metalsj which have their lengths duly propor-
tioned to their expansions and contractions ; but late
writers have advanced several objections to this mode
of compensation. The principal of these objections are:
1st, The length of the pendulum may be increased by
its weight. 2dly, Where the rods pass through the con-
necting bars there is some friction, which causes theiri
to move by starts, and not according to the increase and
decrease of heat: and, 3dly, The difficulty of exactly ad-
justing the lengths of the rods. But there is another
source of error in this pendulum, which has not, I believe,
been attended to by writers on this subject.

Suppose that the distance between the centre of the lens"
and the point of suspension were hot to suffer any change
by the vicissitudes of heat and cold, still the length of the
pendulum might vary. For as the ends of the compensation
rods are connected by cross pieces, and as all these, except
one, are put in motion bv everv variation in the tempera-
ture of the air, some moving in a direction contrary to the
others ; therefore it is evident, that the motions of these
cross bars must alter the distance between the point of
suspension and the centre of oscillation, unless their
weights be adjusted according to their motions to and from
the point of suspension.

Suppose the cross piece which connects the two extreme
rods of the gridiron pendulum be fixed to the centre of
the lens, and that the expansions of steel and brass be as

Vol. 36. No. 148. August 1810. F three

82 On Pendulums,

three to five : then, if the expansion of one of the extreme
steel rods raises the top bar three degrees nearer the point
of suspension, the brass rod, which is joined to the steel
rod at the top, will remove the cross bar fixed to its lower
end, only two degrees from the same point.

To investigate the ratio of the weights of these cross
pieces, that the centre of gravity of the pendulum may re-
main at the same distance from the point of suspension,
in all degrees of heat ; — Let CG represent an inflexible
lever, considered as without weight, kept in equilibrio upon
the fulcrum F, bv three weights, A, B, and W. And let
CF=.r, DF=y, and FG=z.

C D F G

B W

Then per mechanics A x x •{• B x y =W x zf or Ax-\-By
=Wz. And supposing x and y to flow in contrary di-
rections, we have j; + ixA+y-5*xB = Wz = Ax -f By,
Therefore, Ax = By, and consequently, A : B : : y : x.

Hence, if the weights of the cross pieces be inversely as
their motions, they will not alter the distance of the centre
of gravity from the point of suspension, and " the distance
of the centre of suspension from the centre of percussion
or oscillation, in the same body, will always remain the
same; if the distance of its centre of gravity from the
point of suspension, and the plane of its motion (in regard
to the body) remain the same*."

This alteration might improve the gridiron pendulum \
but it would be very difficult to exhibit a theorem com-
pletely accurate for a mode of compensation which is
liable to so many irregularities. A pendulum of a more
simple construction, and that might be more easily ad-
justed for heat and coldv is still an object that merits the
attention of the astronomer.

The mercurial pendulum is founded on principles mor6
simple and correct than any other compound pendulum
that has yet been invented j but the manner of construct-
ing it with a glass rod has- prevented its being more gene-
rally used in the best clocks. This objection is now ob-
viated, by the application of a steel rod with a glass vessel
attached to it containing quicksilver, so that when the

* Emmon's Flnxions, j»age 312. Steel

On Pendulums,

83

Steel rod expands downwards the quicksilver expands up-
wards, and vice versa* The rate of the clock will show
whether the pendulum be over or under corrected ; conse-
quently by taking a little quicksilver out of the bob, or
adding a little, the compensation may be adjusted to the
utmost degree of exactness, and with very little trouble.

It may be supposed that a pendulum cannot be adjusted
for heat and cold by the going of the clock, but the rate of
my clock shows that this supposition is not well founded ;
for when a wooden pendulum was attached to it, its rate
of going was affected merely by dryness and moisture;
but with a mercurial pendulum its rate was affected only by
heat and cold, the pendulum being a small matter under
corrected; but this variation in its rate during twelve
months was. very little more than one second per day, al-
though the temperature of the outward air did not vary
less, by Fahrenheit's scale, than 70 degrees.

The following register of the going of this clock was
computed from the sun's transits over the meridian, ob-
served with a 3{ feet transit telescope.

Lynn, July 16, 1810. E. WALKER.

P. S. For an account of the greatest annual variation in
the daily rate of the transit clock at the Royal Observatory
for six years, see Phil. Mag. vol. xxxiv. p. 4.

An Account of the Going of a Clock ivith a mercurial
Pendulum made by Mr, Barraud.

1809.

Daily

Rate of

the Clock.

No. of
Days.

i 1809.

Daily

Rate of

the Clock.

No. of
Days.

June 27

•/

//

July 1

+ 0-14

4

Aug. 26

-f 0-36

3

4

0*30

3

30

035

4

1)

0*55

7

Sept. 7

0-22

8

13

037

2

9

0-42

2

14

038

1

15

0-20

6

16

018

2

17

0-28

2

19

016

3

21

0*53

4

26

0*30

7

24

0-54

3

31

0-29

5

29

0*48

5

Aug. 8

0*44 ,

8

Oct. J

0*43

2

13

0*30

5

7

0-40

6

17

0*28

4

8

0'41

1

23

0*20 1

6

H

oio 1

3

Fs

Tasw

Si

Oil Pendulums.
Table (Continued).

1609.

Daily

Rate of

tlie Dock.

No. of
Days.

i

1810.

i .

Daily

Rate of

the Clock.

No. of
Days.

26

//
4 0*38

15

April 11

//
4 1*18

13

Nov.

7

0 44

12

16

1-18

5

9

042

2

18

ro8

0

15

051

6

20

roo

2

16

0*37

1

22

0-75

2

19

059

3

23

0-88

1

21

t>'45

2

25

0-44

a

24

0'93

3

27

027

2

27

0*79

3

28

019

1

Dec.

0

0'82

5

29

0-23

1

4

•0*68

2

May 1

0-29

2

10

0*83

6

8

0-52

7

13

0*91

3

11

0-56

3

15

0'85

2

13

0-55

2

21

1-14

6

14

0-55

1

28

0'89

7

18

0-63

4

20

21

0-62
0-39

2

18W-

1

23
£5
26

0-44
0-'29
0-39

2

Jan.

1

5

4-0 85
075

4
4

2

10

0*62

5

27
30

03}
0-23

1
3

Feb.

18
4

0*99
1-11

8
17

T
June 1

0-24

2

5
10

090
1*17

I
5

8
14

0-08
0-32

7
6

14

T22

4

18
21

0-33
0-31

4
3

19

. 1 '04

5

SI

1-09

0

25

0*15

4

Mar.

26
11

1*21
1*24

5

13

29
July 1

0-13
014

4
2

18

105

7

7

0*14

6

22

3*16

4

9

0*14

2

23

096

1

12

0*16

3

25

088

2

29

1*08

• 4 i

'

XV. 2>

£ 85 ]

XV. The Bakerian Lecture for 1609. On some new Elec-
trochemical Researches on various Objects, particularly
the metallic Bodies, from the Alkalies, and Earths,
and on some Combinations of Hydrogen. By Iliw-
PHRYDAvr, Esq. Sec. U.S. F.R.S.E. W.R.LJ.

[Concluded from p. 32.]

IV. On the Metals of Earths.

A have tried a number of experiments with the hopes of
gaining the same distinct evidences of the decomposition
of the common earths, as those afforded bv the electro-
chemical processes on the alkalies, and the alkaline earths.

I find that when iron wire ignited to whiteness, by the
power of 1000 double plates, is negatively electrified and
fused in contact with either silex,alumine or glucinc, slightly
moistened and placed in hydrogen gas; the iron becomes
brittle and whiter, and affords bv solution in acids, an
earth of the same kind as that which has been employed
in the experiment.

1 have passed potassium in vapour through each of these
earths, heated to whiteness in a platina tube : the results
were remarkable, and perhaps not unworthy of being fully
detailed.

When silex was employed, being in the proportion of
about ten grains to four of potassium, no gas was evolved,
except the common air of the tube mingled with a little
inflammable gas, not more than might be referred to the
moisture in the crust of alkali, formed upon the potassium.
The potassium* was entirely destroyed; and glass with
excess of alkali was formed in the lower part of the tube ;
when this glass was powdered, it exhibited dark specks,
having a dull metallic character not unlike thatfof the pro-
toxide of iron. When the mixture was thrown into water,
there was onlv a very slight effervescence ; but on the ad-
dition of muriatic acid to the water, globules of gas were
slowly liberated, and the effect continued for nearly an

* The results of this experiment are opposed to the idea that potassium
is a compound of hydrogen and potash or its basis ; for if so, it might be
expected that the hydrogen would be disengaged by the attraction of the
alkali for silex. In my first experiments on this combination, 1 operated
in an apparatus connected with water, and I found that the potassium
produced as much hydrogen as if it hud been made to act upon water; in
this case the metal had rapidly decomposed the Vapour of the water, which
must have been constantly supplied.

F 3 hour ;

66 On some new Electrochemical Researches

hour; so that there is great reason to believe, that the silex
had been either entirely or partially deoxygenated, and was
slowly reproduced by the action of the water, assisted by
the slight attraction of the acid for the earth.

When the potassium was in the quantity of six grains,
and the silex of four grains, a part of the' result inflamed
spontaneously as it was taken out of the tube, though the
tube was quite cool, and left, as the result of its combustion,
alkali and silex. The part which did not inflame, was
similar in character to the matter which has been just de-
scribed, it did not act upon water, but effervesced with
muriatic acid.

Potassium in acting upon alumine and glucine, produced
more hydrogen than could be ascribed to the moisture pre-
sent in the crust of potash ; from which it seems probable
that even after ignition, water adheres to these earths.

The results of the action of the potassium were pyro-
phoric substances of a dark gray colour, which burnt,
throwing off brilliant sparks *, and leaving behind alkali
and earth, and which hissed violently when thrown upon
water, decomposing it with great violence. I examined the
products in two experiments, one on alumine, and one on
glucine, in which naphtha was introduced into the platina
tube, to prevent combustion ; the masses were very friable,
and presented small metallic particles, which were as soft
as potassium, but so small that they could not be separated,
so as to be more minutely examined; they melted in boil-
ing naphtha. Either a part of the potassium must have
been employed in decomposing the earths in these experi-
ments, or it had entered into combination with them ;
which is unlikely, and contrary to analogy, and opposed
by some experiments which will be immediately related.

Supposing the metals of the earths to be produced in
experiments of this kind, there was great reason to expect
that they might be alloyed with the common metals, as
well as with potassium. Mercury was the only substance
which it was safe to try in the tube of platina. In all cases
in which the potassium was in excess, I obtained amal-
gams by introducing mercury, whilst the tube was hot;
but the alkaline metal gave the characters to the amalgam,
and though in the case of glucine and alumine, a white
matter separated during the action of very weak muriatic

* The pyrophorus from alum, which I have supposed in the last Bakerian
lecture to be a compoumd of potassium, sulphur, aud charcoal, probably
contains this substance likewise.

acid

on various Objects, BJ

acid upon the amalgam, yet I could not be entirely satis-
fied that there was any of the metals of these earths in
triple combination.

Mixtures of the earths with potassium, intensely ignited
in contact with iron filings, and covered with iron filings
in a clay crucible, gave much more distinct results. Whe-
ther silex, alumine, or glucine was used, there was always
a fused mass in the centre of the crucible; and this mass
had perfectly metallic characters. It was in all cases much
whiter and harder than iron. In the instance in which
silex was used, it broke under the hammer, and exhibited
a crystalline texture. The alloys from alumine and glu-
cine were imperfectly malleable. Each afforded, by solu-
tion in acids, evaporation, and treatment with re-agents,
oxide of iron, alkali, and notable quantities of the earth
employed in the experiment.

Though I could not procure decided evidences of the
production of an amalgam, from the metals of the com-
mon earths, yet I succeeded perfectly by the same method
of operating,' in making amalgams of the alkaline earths.

By passing potassium through lime and magnesia, aud
then introducing mercury, I obtained solid amalgams^
which consisted of potassium, the metal of the earth em-
ployed, and mercury.

The amalgam from magnesia was easily deprived of its
potassium by the action of water. It then appeared as a
solid white metallic mass, which by exposure to the air
became covered with a dry white powder, and which when
acted upon by weak muriatic acid, gave off hydrogen gas
in considerable quantities, and produced a solution of
magnesia.

By operations performed in this manner, there is good
reason to believe, it will be possible to procure quantities
of the metals of the alkaline earths, sufficient for determin-
ing their nature and agencies, and the quantities of oxygen
which they absorb ; and by the solution of the alloys con-
taining the metals of the common earths, it seems pro-
bable, that the proportions of metallic matter in these
bodies may likewise be ascertained.

On an hypothesis which I have before brought before
the Society, namely, that the power of chemical attraction
and electrical action may be different exhibitions of the
same property of matter, and that oxygen and inflamma-
ble bodies are in relations of attraction which correspond
to the function of being negative and positive respectively,
it would follow that the attractions of acids for salifiable

F 4 bases

88 On some new. Electrochemical Researches

bases would be inversely as the quantity of oxygen that
they contain ; and supposing the power of attraction to be
measured by the quantity of basis which an acid dissolve?,
it would be easy to infer the quantities of oxygen and me-
tallic matter from the quantities of acid and of basis in a
neutral salt. On this idea 1 had early in 1808 concluded
that barytes must contain least oxygen of all the earths,
and that the order as to the quantity of inflammable matter
must be strontites, potash, soda, lime, and so on ; and that
silex must contain the largest quantity of oxygen of all.

If the most accurate analyses be taken, barytes may be
conceived to contain about 90*5* of metal per cent, stron-
tites 86f, lime 73 5*, magnesia 66 J,

The same proportion would follow from an application
of Mr. Dalton's ingenious supposition§, that the proportion
of oxygen is the same in all protoxides, and that the quan*
tity of acid is the same in all neutral salts, i. e. that every
neutral salt is composed of one particle of metal, one of
oxygen, and one of acid.

We are in possession of no accurate experiments on the
quantity of acids required to dissolve alumine, glucine,
and silex; but according to Richter's estimation of the
composition || of phosphate of alumine, alumine would
appear to contain about 56 per cent, of metallic matter,

* Mr. James Thompson, Nicholson's Journal, 1809, p. 175, and Berthier.

f Mr> Clayfield. Thomson's Chemistry, vol. ii. p.'626, 629.

$ Murray's Chemistry, vol. iii. p. 616.

§ The principle that I have stated of the afhnity of an acid for a salifia-
ble basis being inversely as the quantity of oxygen contained by the basis,
though gained from the comparison of the electrical relations of the earths,
with their chemical affinities, in its numerical applications, must be consi-
dered merely as a consequence of Mr. Dalton's law of general proportions.
Mr. Dalton had indeed, in the spring of 1808, communicated to me a series.
of proportions for the alkalies and alkaline earths; which, in the case of the
alkalies, were not very remote from what I had ascertained by direct ex-
periments. M. Gav Lussac'3 principle, that the quantity of acid' in metallic
salts is directly as the quantity of oxygen, might (as far as it is correct) be
inferred from Mr.jDalton's law, though thia ingenious chemist states that he
was led to it by different considerations. According to Mr. Dalton, there
is a proportion of oxygen, the same in all protoxides, and there^ is a pro-
portion of acid, the same in all neutral salts; and new proportions of oxy-
gen and of acid are always multiples of these proportions. So that if 3
protoxide in becoming a deutoxide takes up more acid, it will be at least
double the quantity, and in these cases the oxygen will be strictly as the
acid. Mr. Dalton s law even provides for ea;>es to which M. Gay Lussac's
will not apply, a deutoxide may combine with a single quantity of acid, or
a protoxide with a double quantity. Thus in the insoluble oxysulphat of
iron perfectly formed, (as some experiments which I have lately made seem
to show,) there is probably only a single proportion of acid ; and in the
8uper-tartrite of potash there is only a single quantity of oxygen, and a
double quantity of acid. Whether Mr. Dalton's law will apply to all casest
~i& a question which I ^hall not in this place attempt to discuss.

I] Thomson's Chemistry, vol. ii. p. 531. JVJ, Ber*

on various Objects. 89

Jvf . Berzelius *, in a letter which 1 received from him a
few months ago, states, that in making an analysis of cast
iron, he found that it contained the metal of silex, and m&£
this metal in being oxidated took up nearly halt* its weight
of oxygen.

If the composition of ammonia be calculated upon, ac
cording to the principle above stated, it ought to consist of
53 of "metallic matter, and about 47 t of oxygen, whic*.
agrees verv nearly with the quantity off hydrogen and
ammonia produced from the amalgam.

Though the early chemists considered the earths and the
metallic oxides as belonging to the same class of bodies,
and the earths as calces which they had not found the
means of combining with phlogiston, and though Lavoisier
insisted upon this analogy with his usual sagacity, yet still
the alkalies, earths, and oxides have been generally con-
sidered as separate natural orders. The earths, it has been
said, are not precipitated by the triple prussiates, or by the
solutions of galls t ; and the alkalies and alkaline earths
are both distinguished by their solubility in water; but if
such characters be admitted as grounds of distinct classi-
fication, the common metals must be arranged under many
different divisions ; and the more the subject is inquired
into, the more distinct will the general relations of all me-
tallic substances appear. The alkalies and alkaline earths
combine with prussic acid, and form compounds of dif-
ferent degrees of solubility ; and solutions of barytes (as
has been shown bv Dr. Henry and M. Guvton) precipitate
the triple prussiate of potash; the power of combination is
general, but the compounds formed are soluble in different
degrees in water. The case is analogous with solutions off
galls ; these, as I have mentioned in a paper published in
the Philosophical Transactions for 180.5, are precipitated by
almost all ncuirosaline solutions; and they form com-
pounds more or less soluble in water, more or less coloured*
and differently coloured with all salifiable bases. It is
needless to dwell upon the combinations of the alkalies and

* In the same communication this able chemist Informed me, that lie had
.succeeded in decomposing the earths, by igniting them strongly with iron
and charcoal.

f I take the proportions of the volumes from the very curious paper of
jMT. Gay Lussac, on the combinations of gaseous bodies, Mnu. d\hiutil>
fom. ii. page '-'13, and the weights from mv own estimation, according to
which 100 cubic inches of muriatic acid gas weigh 39 grains, at the mean
temperature and pressure, which is very nearly the same as the weight
given by MM. Gay Lussac and Thenard.

£ Ktaproth, Annates de Ckuuir, tome s, ;•:. *77.

earths,

QO On some new Electrochemical Researches

earths, with oils, to form soaps ; and of the earthy soaps,
some are equally insoluble with the metallic soaps. The
oxide of tin, and other oxides abounding in oxygen, ap-
proach very near in their general characters to zircon, silex,
and alumine ; and in habits of amalgamation, and of alloy,
how near dp the metals of the alkalies approach to the
lightest class of oxidable metals !

It will be unnecessary, I trust, to pursue these analogies
any further, and I shall conclude this section by a few re-
marks on the alloys of the metals of the common earths.

It is probable that these alloys may be formed in many
metallurgical operations, and that small quantities of them
may influence materially the properties of the compound
jn which they exist.

In the conversion of cast into malleable iron, by the
process of blooming, a considerable quantity of glass se-
parates^ which, as far as I have been able to determine,
from a coarse examination, is principally silex, alumine,
and lime, vitrified with oxide of iron.

Cast iron from a particular spot will make only cold-
short iron ; whilst, from another spot, it will make hot-
short ; but by a combination of the two in due propor-
tions, good iron is produced ; may not this be owing to
the circumstance of their containing different metals of the
earths, which in compound alloy may be more oxidable
than in simple alloys, and may be more easily separated
by combustion ?

Copper, M. Berzelius informs me, is hardened by sili-
cium. In some experiments that I made on the action of i
potassium and iron on silex, the iron, as I have mentioned
before, was rendered white, and very hard and brittle, but
it did not seem to be more oxidable. Researches upon
this subject do not appear unworthy of pursuit, and thev
may possibly tend to improve some of our most important
manufactures, and give new instruments to the useful arts.

V. Some Considerations of Theory illustrated by new
Facts.

Hydrogen is the body which combines with the largest
proportion of oxygen, and yet it forms with it a neutral
compound. This, on the hypothesis of electrical energy,
would show that it must be much more highly positive
than any other substance ; and therefore, if it be an oxide,
it is not likely that it should be deprived of oxygen by any
simple chemical attractions. The fact of its forming a
substance approaching to an acid in its nature, when com-

binet|

on various Objects . • 91

bined.with a metallic substance, tellurium, is opposed to
the idea of its being a gaseous metal, and perhaps to the
idea that it is simple, or that it exists in its common form
in the amalgam of ammonium. The phenomena presented
by sulphuretted hydrogen are of the same kind, and lead to
similar conclusions.

Muriatic. acid gas, as I have shown, and as is further
proved by the researches of MM. Gay Lussac and Thenard,
is a compound of a body unknown in a separate state, and
water., The water, I believe, cannot be decompounded,
unless a new combination is formed : thus it is not changed
by charcoal ignited in the gas by Voltaic electricity ; but
it is decompounded by all the metals ; and in these cases
hydrogen is elicited, in a manner similar to that in which
one metal is precipitated by another; the oxygen being
found in the new compound. This, at first view, might
be supposed in favour of the idea that hydrogen is a simple
substance ; but the same reasoning may be applied to a
protoxide as to a metal ; and in the case of the nitromu-
riatic acid, when the nitrous acid is decomposed to assist
in the formation of a metallic muriate, the body disengaged
(nitrous gas) is known to be in a high state of oxyge-
nation.

That nitrogen is not a metal in the form of gas, is al-
most demonstrated by the nature of the fusible substance
from ammonia, and (even supposing no reference to be
made to the experiments detailed in this paper) the general
analogy of chemistry would lead to the notion of its being
compounded.

Should it be established by future researches that hvdro-
gen is a protoxide of ammonium, ammonia a deutoxide,
and nitrogen a tritoxide of the same metal, the theory of
chemistry would attain a happy simplicity, and the existing
arrangements would harmonize with all the new facts.
The class of pure inflammable bases would be metals ca-
pable of alloying with each other, and of combining with
protoxides. Some of the bases would be known only in
combination, those of sulphur, phosphorus*, and of the

boracic,

* The electrization of sulphur and phosphorus goes far to prove that
they contain combined hydrogen. From the phenomena of the action of
potassium upon them in my first experiments, I conceived that they con.
tained oxygen, though, as I have stated in the appendix to the last Bakerian
lecture, the effect* may he explained on a different supposition. The vivid*
ness of the ignition in the process appeared an evidence in favour of their
containing oxygen, till I discovered that similar phenomena were produced
by the combination of arsenic and tellurium with potassium. In some iate
(experiment* on the action of putassium on sulphur and phosphorus, and on

sulphuretted

02 On some new Elect rocfimnical Researches

boracic, fluoric, and muriatic acids ; but the relations of
their compounds would lead to the suspicion of their being
metallic. The salifiable bases might be considered either
as protoxides, deutoxides, or tritoxides : and the general
relations of salifiable matter, to acid mutter, might be sup-
posed capable of being ascertained by their relations to
oxygen, or bv the peculiar state of their electrical energy.

The whole tenour of the antiphlogistic doctrines neces-
sarily points to such an order; but in considering the facts
under other points of view, solutions may be found, which,
if not so simple, account for the phenomena with at least
equal facility.

If hydrogen, according to an hypothesis to which I have
often referred, be considered as the principle which gives
inflammability, and as the cause of metallization, then our
list of simple substances will include oxygen, hydrogen,
and unknown bases only ; metals and inflammable solids
will be compounds of these bases, with hydrogen; the
earths, the fixed alkalies, metallic oxides, and the common
acids, will be compounds of the same bases, with water.

The strongest arguments in favour of this notion, in
addition to those I have before stated, which at present
occur to me, are: First, The properties which seem to be
inherent in certain bodies, and which are either developed
or concealed, according to the nature of their combinations.
Thus sulphur, when it is dissolved in water either in com-
bination with hydrogen or oxygen, uniformly manifests
acid properties ; and the same quantity of sulphur, whe-
ther in combination with hydrogen, whether in its simple
form, or ih combination with one proportion of oxygen,
or a double proportion, from my experiments seems to
combine with the same quantity of alkali. Tellurium,
whether in the state of oxide or of hydruret, seems to have
the same tendency of combination with alkali; and the
alkaline metals, and the acidifjable bases, act with the
greatest energy on each other.

sulphuretted hydrogen, and on phosphurettcd hydrogen, I find that the
phenomena differ very much according to the circumstances ot the experi-
ment, and in some instances I have obtained a larger volume of gas front
potassium after it had been exposed to the action ot certain ot these bodies,
than it would haye*gtven »!one. These experiments are still in .progress,
and I shall soon lay an account of them before the Society. The idea of the
existence of oxygen in sulphur and phosphorus is however still supported
bv various analogies- Their being nonconductors of electricity is one ar-
gument in favour of this. Potassium and sodium I find when heated in
hydrogen, mixed with a small quantity of atmospheric air, absorb both
o'<vgen and hydrogen, and become nonconducting inflammable bodies anaT
logous to resinous and oily substances.

Second,

th various Objects* 03

Second, The facility with which metallic substances
are revived, in cases in which hydrogen is present. I
placed two platina wires, positively and negatively electri-
fied from 500 double plates of six inches, in fused litharge ;
there wa3 an effervescence at the positive side, and a black
matter separated at the negative side, but no lead was pro-
duced ; though when litharge moistened with water was
employed, or a solution of lead, the metal rapidly formed :
the difference of conducting power may be supposed to
produce some difference of effect, yet the experiment is
favourable to the idea, that the presence of hydrogen is
essential to the production of the metal.

Third, Oxygen and hydrogen are bodies that in all cases
seem to neutralize each other, and therefore in the products
of combustion it might be expected that the natural ener-
gies of the bases would be most distinctly displayed, which
is the case; and in oxymuriatic acid, the acid energy seems
to be blunted by oxygen, and is restored by the addition of
hydrogen.

In the action of potassium and sodium upon ammonia,
though the quantity of hydrogen evolved in my experi-
ment* is not exactly the same as that produced by their
action upon water; yet it is probable that this is caused by
the imperfection of the process*; and supposing potassium
and sodium to produce the same quantity of hydrogen from
ammonia and water, the circumstance, at first view, may be
conceived favourable to the notion that they contain hy-
drogen, which under common circumstances of combina-
tion will be repellent to matter of the same kind : but
this is a superficial consideration of the subject, and the
conclusion cannot be admitted ; for on the idea that in
compounds containing gaseous matter, and perhaps com-
pounds in general, the elements are combined in uniform
proportions; then whenever bodies known to contain hy-
drogen are decomposed by a metal, the quantities of
hydrogen ought to be the same, or multiples of each other.
Thus, in the decomposition of ammonia by potassium and
sodium, two of hydrogen and one of nitrogen remain in

* There seems to be always the same proportion between the quantity of
ammonia which disappears., and the quantity of hydrogen evolved ; i. e.
whenever the metals of the alkalies act upon ammonia, supposing this body
to be composed of thrcs hydrogen, and one of nitrogen, in volume, two of
hydrogen and one of nitrogen remain in combination, and one of hydrogen
u set free. And it may be adduced as a strong argument in favour of the
theory of definite proportions, that the quantity of the metals of the alkalies
and nitrogen, in the fusible' results, are in the same proportions as those In
which they eaUt in the alkaline nitrates.

combination.

94 On some new Electrochemical Researches

combination, and one of hydrogen is given off; and in
the action of water on potassium to form potash, the same
quantity of hydrogen ought to be expelled. From my
analysis* of sulphuretted hydrogen, it would appear, that
if potassium in forming a combination with this substance
sets free hydrogen, it will be nearly the same quantity as it
would cause to be evolved from water. And if the analysis
of Mr. Proust and Mr. Hatchett, of the sulphuret of iron,
be made a basis of calculation, iron, in attracting sulphur
from sulphuretted hydrogen, will liberate the same propor-
tion of hydrogen as during its solution in diluted sulphuric
acid ; and taking Mr. Dalton's Jaw of proportion, the case
will be similar with respect to other metals : and if such
reasoning were to be adopted, as that metals are proved to"
be compounds of hydrogen, because, in acting upon dif-
ferent combinations containing hydrogen, they produce
the evolution of equal proportions of this gas, then it might
be proved that almost any kind of matter is contained in
any other. The same quantity of potash, in acting upon
either muriate, sulphate, or nitrate of magnesia, will pre-
cipitate equal quantities of magnesia; but it would be ab-
surd to infer from this, that potash contained magnesia, as
one of its elements ; the power of repelling one kind of
matter, and of attracting another kind, must be equally de-
finite, and governed by the same circumstances.

Potassium, sodium, iron, mercury, and all metals that I

* The composition may be deduced from the experiments in the last
Bakerian lecture, which show that it contains a volume of hydrogen equal
to its own. If its specific gravity be taken as 35 grains, for 100 cubical
inches, then it will consist of 227 of hydrogen, and 32*73 of sulphur. When
sulphuretted hydrogen is decomposed by common electricity, in very refined
experiments, there is a slight diminution of volume, and the precipitated
sulphur has a whitish tint, and probably contains a minute quantity of hy-
drogen. When it is decomposed by Voltaic sparks, the sulphur is precipi-
tated in its common form, and there is no change of volume ; in the last case
the sulphur is probably ignited at the moment of its production. In some
experiments lately made in the laboratory of the Royal Institution, on ar-
seniuretted and phosphuretted hydrogen, it was found that when these gases
were decomposed by electricity, there was no change in their volumes ; but
neither the arsenic nor the phosphorus seemed to be thrown down in their
common state * the phosphorus was dark-coloured, and the arsenic appeared
as a brown powder, both were probably hydrurets : this is confirmed like-
wise by the action of potassium upon aseniuretted and phosphuretted hy-
drogen ; when the metal is in smaller quantity than is sufficient to decom-r
pose the whole of the gases, there is always an expansion of volume ; so that
arse.iiuretted and phosphuretted hydrogen contain in equal volumes, more
hydrogen than sulphuretted hydrogen, probably half as much more, or
twice as much more. From some experiments made on the weights of phos-
phuretted and arseniuretted hydrogen, it would appear that 100 cubic inches
of the first weigh about JO grains, at the mean temperature and pressure,
*nd 100 of the second about 15 grains.

have

on various Objects. £5

have experimented upon, in acting upon muriatic acid gas,
evolve the same quantity of hydrogen, and all form dry
muriates ; so that any theory of metallization, applicable
to potash and soda, must likewise apply to the common
metallic oxides. If we assume the existence of water in
the potash, formed in muriatic acid gas, we must likewise
infer its existence in the oxides of iron and mercury, pro-
duced in similar operations.

The solution of the general question concerning the
presence of hydrogen in all inflammable bodies, will un-
doubtedly be influenced by the decision upon the nature of
the amalgam from ammonia, and a matter of so much im-
portance ought not to be hastily decided upon. The diffi-
culty of finding any multiple of the quantity of oxygen,
which may be supposed to exist in hydrogen, that might
be applied to explain the composition of nitrogen from the
same basis, is undoubtedly against the simplest view of the
subject. But still the phlogistic explanation, that the me-
tal of ammonia is merely a compound of hydrogen and
nitrogen ; or that a substance which is metallic can be
composed from substances not in their own nature metallic,
is equally opposed to the general tenour of our chemical
reasonings.

I shall not at present occupy the time of the Society by
entering any further into these discussions ; hypothesis can
scarcely be considered as of any value, except as leading to
new experiments; and the objects in the novel field of
electrochemical research have not been sufficiently ex-
amined to enable to decide upon their nature, and their
relations, or to form any general theory concerning them
which is likely to be permanent.

Explanation of the Figures,

Fig. 1. The apparatus for electrizing potassium in gases,
A the glass tube. B the wire negatively electrified. C
and D the cup and wire posicivelv electrified.

Fig. 2. The apparatus for decomposing water, out of
the contact of air, page 20. AA the cones containing the
water. BBB the tubes for conveying the gas. C and D
the pneumatic apparatus.

Fig. 3. The apparatus for decomposing and recompos-
>ng water under oil. CC the wires for communicating the
Voltaic electricity. DD the \\4res for producing the ex-
plosion. B the tube. A the vessel containing it. a, d, c,
the level of the different fluids.

Fig. 4. The apparatus for exposing water to the action

©**

96 Report of the Butlin

of ignited potash and charcoal^ out of the contact of air,
A the tube for water. B the iron tube. C the receiver
for the ammonia. D the pneumatic apparatus.

Fig. 5. The apparatus for the decomposition of am-
monia.

Fig. 6. A Voltaic apparatus, being one of the 200 which
compose the new Voltaic battery ot the Royal Institution*
For the construction of this battery, and of other instru-
ments applicable to new researches, a fund of upwards of
^lOOO has been raised by subscription, from members of
the Royal Institution. As yet, the whole combination has
not been put into action ; but reasoning from the effects
of that part of it which has been used, some important
phsenomena may be expected from so great an accumula-
tion of electrical power.

XVI. Report of the Dublin Cow- Pock Institution, under
the Patronage of His Grace the Lord Lieutenant, for
1809.

An Abstract from the Register of Inoculations and Distri-
bution of Matter.

Patients

Inoculated.

Packets issued

to Practioners

in general.

Packets to

Army-
Surgeons.

1804
1805
1806
1807
J 808
1809

578
1,032
1,356
2,156
3,002
3,941

776
1,124
1,340

1,790

2.285
2,540

236
178
220
320
333
244

Totals.

12,065

9,855

1,531

The directors of the institution have great pleasure in
observing the progressive increase of vaccine inoculation,
and the influence of experience in satisfying the public of
its efficacy. Most of the above 12,065 patients being con-
fined to a city where small -pox has been in general preva-
lent, must have been exposed in every possible way to its
infection, by living in the same house, or frequently sleep-
ing in the same bed with the infected. The anxiety of
parents, too, has often led them intentionally to expose their

children

CoW'Pock Institution. 97

children to small- pox infection. As far, however, as the
immediate observation of the Institution extends, cow-
pock has been found to resist all such trials, with three
exceptions only.

It now appears by increasing experience, that in a very
few instances the vaccine infection will form fairly on the
arm, and go through its regular stages, without being ab-
sorbed into the blood. The same thing has repeatedly
happened in inoculating for the small-pox, where no erup-
tive fever or eruption succeeded the inoculation. In the
three cases of small -pox which have succeeded vaccination,
the disease has been mild and of short duration.

The efficacy of cow-pock, as far as Dublin is concerned,
does not rest upon the proofs adduced in its favour by this
Institution, for it has been extensively practised during the
last five or six years. There are grounds for believing that
the number vaccinated throughout the city, including the
above 12,065, does not fall short of 35,000. The cases of
small-pox following cow-pock which have been reported,
upon any reasonable authority, to the Institution, do not
exceed six. No one who is acquainted with the careless
and inattentive manner in which many practitioners have
hitherto conducted vaccination, can be surprised to hear of
cases of failure. The neglect of parents also to have their
children examined at the regular periods after inoculation,
tends to bring the practice into disrepute. To obviate this
inconvenience, it has been the practice for some time at
this Institution, to oblige parents to deposit a small sum,
to be returned after the child has gone through the disease,
provided they have attended agreeably to instruction; other-
wise the sum is forfeited. This regulation has had the de-
sired effect.

It was reported at an early period of the practice, that
vaccination afforded only a temporary security, which was
at first limited to three years. Numerous experiments,
tried in different quarters, satisfactorily proved the falsehood
of this assertion. A similar opinion has been lately revived,
but the period of security extended to five or six years.
Neither analogv nor experience justifies such an idea, and
the history of casual cow-pock fully refutes the allegation,
as numerous cases are on record of persons, after having
casual cow-pock, resisting during a long life the small-
pox, under every circumstance of exposure, inoculation, &c.
Besides, had the preventive powers of cow-pock not been
permanent, it is but reasonable to suppose that many of
Vol. 36. No, US. August J810. G the

98 Report of the Dublin

the above 12,065 must, under the existing circumstances
of exposure, have taken the small-pox. Above twenty
children who were Vaccinated five or six years ago, have
lately, by order of the directors, been submitted to vario-
lous inoculation, but without the effect of producing small-
pox. Similar experiments have been instituted, under the
direction of other practitioners, with the like result. Nine-
teen children who had the cow-pock eight and nine years
ago, have been lately inoculated with small -pox matter, at
the Foundling Hospital, underlhe inspection of Mr. Stewart,
surgeon-general, and Mr. Creighton, surgeon of the hos-
pital, but with no other effect than local inflammation. —
In a letter just received from Mr. Bryce, of Edinburgh, he
observes: — u I have lately finished an experiment of ino-
culating about twenty children with the small- pox, who
were vaccinated from eight years to five months. — The re-
sult is most satisfactory, and shows clearly that a pustule
with surrounding inflammation is as readily produced five
months after vaccination, as at the end of eight years, con-
sequently that the security is as complete at the latter pe-
riod as the former."

The following extract from the Report of the Small-Pox
Hospital, London, should be recorded : — " Eleven thou-
sand eight hundred patients, and upwards, have been vac-
cinated, of which number twenty -five hundred were after-
wards proved to be secured from the natural small-pox, by
receiving a further inoculation with small -pox matter,
which took no effect. A number amply sufficient to sa-
tisfy the public mind, of the security and success of the
new practice of vaccination." — December, 1802. — So great,
a number submitted to the test of variolous inoculation,
and exposed in a hospital full of small-pox infection with-
out effect, should of itself convince every reasonable mind

of the efficacy of vaccination. VidelS/h. Charles Murray's

Answer to Mr. Highmore, p. 37.

A report having been lately circulated, that Dr. Jenner
himself was beginning to entertain some doubt of the
efficacy of his discovery, the directors thought it expedient
to direct their secretary to write to him, and to lay his an-
swer upon the subject before the public.

u Dear sir, — Your obliging letter of the 3d instant, in-
closing the Annual Report of the Cow-Pock Institution, in
Dublin, has just reached me. The former letter you allude
to, has not yet been delivered. It is with the greatest plea-
sure I perceive the rapid increase of vaccination in your

metropolis,

Cow-Pock Institution. 09

metropolis, and the uninterrupted success that has attended
the practice, at once a proof of the zeal, industry and at-
tention of the medical officers \ for which I beg leave to
make my most grateful acknowledgements.

" And now, sir, a few remarks on the very extraordinary
communication you have make to me respecting Lady
C -. It has been one of the usual devices of the ene-
mies of vaccination, almost from the time of my first mak-
ing it known, to represent me as having lost my confidence
of its prophylactic powers, or, at least, that I was wavering
on the subject. Can T, who, with the aid of my nephews,
have vaccinated a number of persons little short of 30,000,
without one single instance of accident or of failure, that
ever reached my ears, for a moment entertain such an ab-
surd idea? Or could I have ever thought of inoculating
for the small-pox, while I hold that practice in abhorrence,
and condemn it both publicly and privately ? Believe me,
the whole story you relate to me is an entire fiction, with-
out the faintest shadow of foundation. Never from the
commencement of my experiments to the present hour,
have I used a particle of variolous matter, except for the
purpose of putting some of those to a test on whom I
made my first trials. For some years past, I have relied
wholly on the vaccine lymph, for testing those on whom
any material irregularity appeared in the progress of the
pustule.

u Believe me, &c.

Berkeley, Feb. 19, 1809. « EDWARD JeNNER."

While the directors, with such weight of evidence in its
favour, feel themselves warranted in continuing to recom-
mend vaccination as a preventive of small-pox, they cannot
but regret that in a few cases it has been difficult to deter-
mine whether a patient has had the disease constitutionally
or locally. They however confidently hope that by pur-
suing Mr. Bryce's test, and by increased attention to the
progress of the disease, practitioners will be enabled to sur-
mount the only objection to a practice which tends to pre-
serve more than 30,000 lives annually, in the British Isles>

Mr. Bryce proposes that a 3econd inoculation be per-
formed about the sixth day after the first : the vesicle pro-
duced by this second inoculation is accelerated in its pro-
gress, so as to arrive at maturity, and again fade, at nearly
the same time as the affection arising from the first inocu-
lation. Mr, B. considers the acceleration of the second

G 2 inoculation

100 Report of the Dulliii

inoculation to be the effect of the constitutional affection
produced by the first ; and therefore, if it shall be found that
no such acceleration takes place, but that the second ino-
culation proceeds by a slow progress through all the stages,
it is to be concluded, that no constitutional action has taken
place from the first insertion of the virus ; and when this is
the case, the second inoculation must be regarded as a pri-
mary affection, and a third puncture made according to the
plan laid down for conducting the second inoculation ; and
thus (he says) we may go on until the proper test be ob-
tained; or until we be satisfied that the constitution com-
pletely resists the action of cow-pock.

Although small-pox is by no means exterminated from
Dublin, among the poor, yet the general substitution of
vaccine for variolous inoculation has considerably di-
minished the number of patients brought to the hospitals
and dispensaries for advice. In the upper ranks of society
death from small -pox is unheard-of, and the most exten-
sive practitioners acknowledge that a case of small-pox in
private practice is a very rare occurrence. And although
the reintroduction of small-pox into society would add
greatly to the emoluments both of physic and surgery,
there is no liberal man in either profession who would not
sincerely deplore such a calamity.

Signed by order,

January 10,1810. "S. 13. Labatt, Secretary.

Foundling Hospital, Dublin, Jan. 4, 1810.

The following Report having been laid before the Governors
of the Foundling Plospital, and appearing to be highly
satisfactorv: — Ordered, That three thousand copies there-
of be printed, for the purpose of their being circulated as
generally throughout the United Kingdom as possible.

By order,

A. Bailie, Register.

AS some persons have lately attempted to prejudice the
minds of the public by representing vaccine inoculation as
a doubtful security against small- pox, limiting its' influence
to a certain period, and wishing us to believe that its pre-
ventive powers diminish in proportion to the distance of
time from inoculation ; — I have, therefore, at the request
of the right honourable and honourable the governors of
the Foundling Hospital, instituted such experiments as
enable me (a second time) to congratulate the public on
their successful event. From

Cow-Pock Institution. 101

From my situation, as surgeon to the Foundling Hospi-
tal, I have had it fully in my power to select such cases as
had been faithfully recorded by me to have undergone vac-
cination at the earliest period of cow-pock inoculation in
this city, and such have been approved of by those gentle-
men who have honoured me with their presence, to wit-
ness and subscribe their names to the progress and event
of the following experiment on nineteen children chosen
for the purpose, who were divided into two (.lasses. The
first nine comprehend those who in a state of infancy were
vaccinate d I v me between the 30th of December 1800
and 3d of July 1801, now more than eight years. These
were again inocuUucd with sn»all-pox infection by George
Stewart, esq. surgeon-general, on the 24th of July, 1804,
(and witnessed by several gentlemen of the first respecta-
bility in their profession,) m like manner to disprove the
assertions of Mr. Goldson, as may be seen in the twelfth
volume of the Medical ami Physical Journal, and with the
most complete success — all having resisted the small-pox,
although exposed to it in every way possible. These nine
children, with ten others, who were also vaccinated by me
in a state of infancy, from 15th of July 1801 to 30th of
August 1802, upwards of seven years, were again submitted
to small-pox inoculation, on Friday, 22d of December last;
the infection taken from a child of Mr. Stafford's, No. 7,
Hanbury-lane, in confluent small-pox, and the matter in-
serted in two places in the arm of each child, in a fluid
state,- and in the greatest quantity. In every instance, the
punctures in the arm of each child from the third day in-
flamed, and continued until the seventh, when the inflam-
mation gradually subsided, as certified by Mr. Stewart, and
marked in a table, which, in another publication, will be
more fully expressed ; — which circumstance has proved the
activity of the small-pox matter inserted, and which must
have affected the constitution, were it in the least suscepti-
ble of the disease. Fourteen days have now elapsed, the
inflammation of the punctures is entirely gone, and never
was attended with the slightest fever, sickness, or eruption.

J n corroboration of the above facts, conducted with
everv decree of accuracy, and which cannot admit of the
smallest doubt on the minds of those gentlemen who have
witnessed them, and hereunto subscribed their names; I
can safelv assert, that T have submitted upwards of five
hundred infants and children, vaccinated by me at this In-
stitution, and at the Dispensary for Infant Poor and Cow-

G 3 pock

102 Mr. Smeaton's Harks, &?c*

pock Inoculation, as established in the year 1800, to a like
experiment, and with the same result in every instance.

Dublin, Mcrrion-square, West, J# CllEIGHTON.

January 4, 1810.

George Stewart, A. Colles,

Gustavus Hume, William Hartigan,

S. Wilmot, . Philip Crampton,

Ralph S. Obre,
Members of the Royal College of Surgeons in Ireland.

Edmund Connell, William Dillon,
Samuel Bell, James M'Creight,

Apothecaries.

XVII. Information, that a further Publication of the late
Mr, Smeaton's Engineery Designs and Papers is in
hand. — Copy of a. List of the principal British Strata,
by the late Rev. John Michel, (of whose posthumous
Papers on Geological Subjects, further Information is
requested ;) — witfi some Experiments of Mr. Smeaton's
on Limestones, — and Queries respecting Mr. Tofield.
Communicated by Mr. John Farey.

To Mr. Tilloch.

Sir, As my eldest son was a few days ago employed, in
examining the miscellaneous bundles of papers, which be-
longed to the late ingenious Mr. John Smeaton, the civil
engineer, now in Sir Joseph Banks's possession, with a
view to the further publication by Messrs. Longman, Hurst,
Rees,andCo. of hisDrawings and Reports on civil engineery,
which so long and impatiently have been expected by those
interested in this branch of the useful arts? he found a small
scrap of paper (only four inches by three) in the hand-
writing of Mr. Smeaton, part of the cover of a letter, as
appears by part of a seal and the London post-mark of
November 21, 1788, on the back of it, which, having ob-
tained Sir Joseph's permission, I think of sufficient im-
portance, in a geological point of view, to request the
favour of you to lay before your readers.

It relates to the order and thicknesses of the strata in
England, as appears by Mr. Smeaton's title or endorse-
ment on it, viz. " Mr. Michel's account of the south of
.England strata," \\hich is as follows, viz.

Yards

f Chalk 1 20 ►

Golt 50

Sand,

Mr. Smeaton9 s IFvrks, Gte 103

Yards

Sand, of Bedfordshire 10 or 20

Northampton lime and Portland; limes \

lying in several strata J

Lyas strata 70 or 100

Sand, of Newark about 30

Ked elay, of Tuxford and several 100

Sherewood Forest, pebbles and gravel ... 50 unequal

Very fine white sand uncertain

Roch Abbey and Brotherton limes 100

Coal strata,' of Yorkshire "

The Mr. Michel alluded to, was, it appears, the late Rev.
John Michel, rector of Thornhill, near Wakefield, York-
shire, who was an intimate friend of Mr. Smeaton, the late
Mr. Cavendish, Sec. &c, and whose name must be very
familiar to most of your readers, from his (natty valuable
papers in the Transactions of the Royal Society of London,
of which he was a member.

This account of the strata, imperfect as it is, appears to
me important, as showing, that Mr. Michel was acquainted
with the principal features of the south of England strata,
at an earlier period than any thing was published on the
subject, especially if we suppose, as is most reasonable,
that this communication was made verbally by Mr. Michel
to his friend Mr. Smeaton, very soon after November 1788,
who took it down on the cover of a recent letter, as being
the only piece of paper then at hand; for Mr. Smeaton's
decease in September 1792? shows that it must have been
prior to that time.

It appears to me probable, that this account was princi-
pally made from the result of Mr. Michel's observations,
m his journeying* by thegreatNorth road between the place
of his residence and London; The " chalk" being that
which appears from near Hatfield to Baldock ; the " golt"
being the chalk- marie (and perhaps some alluvial clays
also) thence to near Sandy in Bedfordshire; where, doubt-
less, the " sand" is situate, to which he alludes. Jn cross-
ing Northamptonshire from Wansford to Stamford, the
" limes" are first noticed, which he rightly associates with,
and considers the same as, those of Portland-Island, though
distant 170 miles therefrom in a straight line! The next
are the " lyas" strata, which appear between Grantham and
Balderton; and here, the use of a term for these strata of
limestone, which was not then known or in use, I believe,
nearer than Gloucestershire or Somersetshire, shows again

G 4 that

104 Mr: Smeatoiis Works > &c

that Mr. Michel had contemplated the identity of the Bri-
tish strata over wide spaces *. The "sand" of Newark
is seen on its S.E. side near Baldcrton : the wt red clay" of
Tux ford is noticed as the produce of "several" other
places, and is the gypseous earth, or red marie, which
forms so conspicuous a figure across a large portion of the
middle and western parts of England. Sherwood Forest
<( pebbles and gravel," over the northern skirt of which,
this road passes between Tuxford anil Doncaster, is noticed
by Mr. Michel, as being " unequal " in thickness ; and if
his observations had been further extended, it would doubt-
less have appeared clear to him, that the same ought not
to have been taken into his list of strata, anv more than
the numerous other patches of alluvium on the surface
which he must have passed in this road, and has not
noticed ; and particularly so, if 1 am right in conjecturing,
that the " very fine white sand," which he mentions, as of
" uncertain" thickness, is enveloped, ds an accidental bed
in the if red clay," (wluch he had before mentioned) si-
milar to what we find at Norman ton on the S. of Derby,
and some few other places, for the occurrence is rather rare,
J believe, and should therefore wish much to learn, the
precise spot or pits to which Mr. Michel here alludes 3 it
being a part of the country which I have never visited.

The " lime" of Brotherton being associated with that of
Roche-Abbey, 25 miles S.S.E. of it, shows again, that
Mr. Michel had discovered some at least of those geolo-
gical principles, which the labours of Mr. William Smith
very soon after tended to confirm, and to render them of
the utmost practical use and importance.

Mr. Michel was also aware, that the coal-strata known
in Yorkshire, are under-measures to the yellow lime, above
mentioned : it must however be observed, that the thick*
nesses in the above list are most of them (except perhaps
the chalk, the golt, and the Balderlon sand) greatly under*
rated ; while many very thick or important strata (of which
J intend to give a short account in my Derbyshire Report)
are omitted altogether ; as the Bagshot-heath sand, the

* The lyas or blue lias limestone {laving been much the object of Air.
Smeaton's notice, on account of its important quality of making a durable
mortar which sets suddenly and very hard, even under sea- water, as he
proved in the building- of the Eddystone light-hoti.'e. and others of his
great works; and with whose appearance at Aberthaw and Watchet on
the opposite shores of the Bristol Channel, and numerous other places, he
was so well acquainted, was probably the reason, why so very lacunic a
fnention of the^e strata is here made by Mr. Smeaton.

London

Mr. SmealorCs Wvrks, &c. 105

London clay, the Woolwich or Black- heath sand, the
Avlesburv limestone, the Chinch clay*, the Be Iford lime-
stone and clays, beneath it, the Barnack rag, and Colley-
weston lime and slate, the Foston blue clay, and the Maid-
well lime, all of which occur above the lias-clay; while
the coal series above the yellow lime (under the Sherwood
gravel as I suspect) and the important blue beds in the
yellow limestone series, are unnoticed : enough however is
contained in the above list, to show, that the late Rev.
John Michel ought to he ranked among those, to whom
geological science is indebted; and I take this method of
addressing myself to those, who may be now in possession
of his papers, to search for and communicate whatever de-
tails they may contain on the British strata, that will either
further explain the above communication to Mr. Smeaton,
or show the source, whence Mr. M. may have derived the
above particulars of the South British strata f: which
would be conferring a great obligation on

Your obedient humble servant,

1 2, Upper Crown Street, Westminster, JOHN FAREY, Sen.

August 4, J 810.

XV1H. An

* Between the Bedfordshire orWobuin sand, and the Northamptonshire
limes or Bath freestone, which clay extends under almost all the Lincolnshire
fens, and most of those in Cambridgeshire and in Yorkshire.

t P. S. Since writing the above I have been informed, that Mr. Michel,
whose death happened April 21, 1793, was at an early part of his life keeper
of the Woodwardian collection of fossils at Cambridge, which is thought
by some to be the very best general geological collection in existence,
though made near a century ago, owing to the great care and minuteness
with which the localities and attendant circumstances of the fossils therein,
are described: essential particulars, which1 yet have appeared beneath the
attention of too many of our modern mineralogists and geologists, as it
should seem. It is not improbable, that a comparison of the fossil-; and
their localities, in this celebrated collection, first suggested the ideas of a
determinate order in the British strata to Mr. Michel, and the examination
of his papers is therefore a matter of the greater importance from the pro-
bability, that some such arrangement of the facts in theWoodwardian cata-
logue, may be found among them. Perhaps also, the present keeper of
the Woodwardian collection and papers will have the goodness to inform
us, whether any such arrangement of the British strata in a series is to be
found, or minutes of any such attempts, among the Woodwardian papers?

Another scrap of paper, found among Mr. Smeaton's loose memoran-
dums, contains his experiments on twelve sorts of limestone, by dissolving
40 grains of each in aquafortis, and drying the clayey undissolved res;duum6
in the sun, the weights of which are a» follow, vi/. Grains.

* Yellow lyas, of Axmyister . . . . . . 5^

Ditto with shining spangles (mica probably) . . ££

Yellow snake-stone, of Glastonbury . . . , . . 5

Blue lyas, of Watchet .. .. .. .. 4f

Ditto ofAberthaw

Ditto of Bath

Ditto of Axminster

Yellow clump-stone, of Sherborne .. ., ., 3""

White

4*

C '06 ]

XVTTT. An Analysis of several Varieties of British and
Foreign Salt, (Muriate of Soda,) with a view to ex-
plain their Fitness for different ceconomical Purposes, Bif
William Henry, M.D. F.R.S. Vice-Pres. of the Li-
terary and Philosophical Society, arid Physician to the
Infirmary at Manchester*.

Sect. I. General Observations.

JLn undertaking the series of experiments described in the
following pages, I had not so much in view the discovery
of novelties in science, as the determination, by the careful
employment of known processes, and by the improvement
of methods of analysis, of a number of facts, the establish-
ment of which (it appeared to me probable) might have an
influence on an important branch of national revenue and
industry.

An opinion has for some time past existed, and I believe
has been pretty general both in this and other countries, to
the disadvantage of British salt as a preserver of animal
food; and a decided preference has been given to the salt
procured from France, Spain, Portugal, and other warm
climates, where it is prepared by the spontaneous evapora-
tion of sea water. In conformity with this opinion, large
sums of money are annually paid to foreign nations, for
the supply of an article, which Great Britain possesses, be-
yond almost any other country in Europe, the means of
drawing from her own internal resources. It becomes,
therefore, of much consequence to ascertain, whether this
preference of foreign salt be founded on accurate ex-
perience, or be merely a matter of prejudice; and, in the

Grains.
White lyas, with shining spangles, of Wells . . . . 1|

Brown kmestone, of Plymouth .. .. .. i

of Chidley (Chidgley ?) . . . . 0|

Forty grains of burnt lime in flower, dissolved in aquafortis, left of clayey
ipatter when dried in the sun, as follows, viz.

Blue lyas, of Watchet . . . . . . . . 4{

-• — of Briddistow . . . . . . . . Jtt

The Watchet (residuum) made into a ball just stuck together, the Brid-
distow scarcely."

When I wasai the house of Mr. Jessop the engineer (who was formerly a
pupil and ass'srant of Mr. Smcatoi:) at Butterley in Derbyshire, he mentioned
that a Mr. 'JofteU, a civil engineer of the southern part of Yorkshire, formed
a design 30 years ago, of investigating the British strata. I shall he thank-
ful to any of your readers who can communicate any particulars of this
undertaking, and of its author, if they will do so.

* From Philosophical Transactions for 18 1Q, Fart I.

former

Analysis of British and Foreign Salt, * IOT

former case, whether any chemical difference can be dis-
covered, that may explain the superiority of the one to the
other. '

The comparative fitness of these varieties of salt for the
curing of provisions, which has been a subject of much
controversy among the parties who are interested, can be
decided, it is obvious, in no other way, than by a careful
examination of the evidence on both sides. Where evi-
dence, however, is doubtful, and where there exists, as in
this case, much contrariety of testimony, it cannot be un-
fair to yield our belief to that which best accords with the
chemical and physical qualities of the substances in ques-
tion. Again, if salt of British production should be
proved to be really inferior in chemical purity to foreign
salt, it would be important to ascertain, as the basis of all
attempts towards its improvement, in what, precisely, this
inferiority consists. It seemed desirable, also, to examine
whether any di [Terences of chemical composition exist
among the several varieties of home-made salt, which can
explain their variable fitness for ceconomical purposes.

Such were the considerations that induced me to under-
take an inquiry, which has occupied, for several months
past, a large share of my leisure and attention. I began
the investigation, wholly uninfluenced by any precon-
ceived opinions on the subject ; and I had no motive
\o see the facts in any other than their true light, since I
have no personal* interest, either directly or remotely, in
the decision of the question.

The principal sources of the salt, which is manufactured
in this country, are rock salt, brine springs, and sea water.
The first material is confined entirely, and the second
chiefly, though not wholly, to a particular district of Che-
shire. Of the extent and boundaries of this district, the
process of manufacture, and other circumstances interest-
ing to the mineralogist as well as to the chemist, an ample
and excellent history has feeen given by Mr. Henry Hol-
land, in the agricultural report of the county of Chester*.
Prom hi:* account, I shall extract, in order to render some
parts of this memoir more intelligible, a very brief state-
ment of the characteristic differences of the several varieties
of salt, which are prepared in Northwich and its neigh-
bourhood.

In making the stoved or lump salt, the brine is brought
to a boiling heat, which,, in brine fully saturated, is 226^

* Published in 1808.

of

108 Anctlyis of several Varieties of

of Fahrenheit. This temperature is continued during the
whole process; and as the evaporation proceeds, small
flaky crystals continue to form themselves, and to fall lo
the bottom of the boiler. At the end of from eight to
twelve hours, the greatest part of the water of solution is
found to he evaporated ; so much only being left, as barely
to cover the salt and the bottom of the pan. The salt is
then removed into conical wicker baskets, termed harrows ;
and, after being well drained, is dried in stoves, where it
sustains a loss of about one-seventh of its weight.

On the first application of heat to the brine, a quantity
of carbonate of lime, and sometimes a little oxide of iron,
both of which had been held in solution by an excess of
carbonic acid, are separated ; and are cither removed by
skimming, or are allowed to subside to the bottom of the
pan, along with the salt first formed, and with some sul-
phate oi lime ; and are afterwards raked out. These two
operations are called clearing the pan. Some brines scarcely
require them at all, and others only occasionally. The
whole of the impurities, however, are not thus removed; for
a part, subsiding to the bottom, forms a solid incrustation,
termed by the workmen pan-scale* The portion of this,
which is lowest, acquires so much induration and adhesion
to the pan, that it is necessary to remove it, once every
three or four weeks, by heavy blows with a pick-axe.
These sediments are formed, also, in making the other va-
rieties of salt.

In preparing co?mnon salt, the brine is first raised to a
boding heat, with the double view of bringing it as quickly
as possible to the point of saturation, and of clearing it
from its earthy contents. The fires are then slackened,
and the evaporation is carried on for 24 hours, with the
brine heated to 1600 or 170J Fahrenheit. The salt, thus
formed, is in quadrangular pyramids or hoppers, which are
close and hard in their texture. The remainder of the
process is similar to that of making stoved salt, except that
after being drained it is carried immediately to the store-
house, and not afterwards exposed to heat, an operation
confined to the stoved salt.

The large- grained flaky salt is made with an evapora-
tion conducted at the heat of 130 or 140 degrees. The
salt thus formed is somewhat harder than common salt,
and approaches more nearjy to' the cubic shape of the cry-
stals of muriate of soda.

L;irge-gramed or fishery salt is prepared from brine
heated only to 100° or 110° Fahrenheit. No perceptible

agitation,

British and Foreign Salt, I09

agitation, therefore, is produced it] the brine, and the slow-
ness of the process, which lasts from seven or eight to ten
clays, allows the muriate of soda to form in large, and
nearly cubical crystals, seldom however quite perfect in
their shape *.

For ordinary domestic uses, stoved salt is perfectly
sufficient. Common salt is adapted to the striking and
salting of provisions, which are not intended for sea voy-
ages or warm climates. For the latter purposes, the large-
grained or fishery salt is peculiarly fitted.

On the eastern and western coasts of Scotland, and espe-
cially on the shores of the Firth of Forth, large quantities
of salt are made by the evaporation of sea water. In con-
sequence of the cheapness of fuel, the process is carried on,
from first to last, by artificial heat, at a temperature, I be-
lieve, equal or nearly so to the boiling point, and varying,
therefore, according to the concentration of the brine.
The kind of salt, chiefly formed in Scotland, approaches
most nearly to the character of stoved salt. In some places
a salt is prepared, termed Sunday salt ; so called, in con-
sequence of the fires being slackened between Saturday
and Monday, which increases considerably the size of the
crystals.

I am indebted to Dr. Thomson of Edinburgh, (who gave*
me his assistance with great zeal and alacrity) for an op-
portunity of examining upwards of twenty specimens of
Scotch salt, prepared by different manufacturers. That
distinguished chemist, it appears from a letter which he ad-
dressed to me on the subject, was some time ago engaged
in experiments on Cheshire salt. The particulars he has
lost 5 and he retains only a general rccoS lection of the facts,
which confirms, I am happy to state, the accuracy of the
results obtained. by my own experiments.

At Lvmington in Hampshire, advantage is taken of the
greater heat of the climate, to concentrate the sea water by
spontaneous evaporation to about one-sixth its bulk, before
admitting it into the boilers. One kind of salt is chiefly
prepared there, which most nearly resembles in grain* the
stoved salt of Cheshire. The process varies a little, in some
respects, from that which has been already described. The
salt is not fished (as it is termed) out of the boiler, and
drained in baskets ; but the water is entirely evaporated,
and the whole mass of salt taken out at once, every eight
flours, and removed into troughs with holes in the bottom.

* Cheshire Reports, p. 53, &c.

Through

1 10 Analysis of several Varieties of

Through these it drains into pits made under ground, which
leceive the liquor called bittern or bitter liquor. Under*
the troughs, and in a line with the holes, are fixed upright
stakes, on which a portion or* salt that would otherwise
have escaped, crystallizes and forms, in the course of ten
or twelve days, on each stake, a mass of sixty or eighty
pounds. These lumps are called salt cats. They bear the
proportion to the common salt, made from the same brine,
of one ton to 100.

From the mother brine or bitter liquor, which has drained
into the pits, the sulphate of magnesia is made during the
winter season, when the manufacture of salt is suspended,
in consequence of the want of the temperature required
for the spontaneous evaporation of the sea water. The pro-
cess is a very simple one*. The bitter liquor from the pits
is boiled for some hours in the pans, which are used in sum-
mer to prepare common salt ; and the impurities, which
rise to the surface, are removed by skimming. During
the evaporation, a portion of common salt separates; and
this, as it is too impure for use, is reserved for the purpose
of concentrating the brine in summer. The evaporated
bitter liquor is then removed into wooden coolers eight feet
long, five feet wide, and one foot deep. In these it re-
gains twenty- four hours, during which time, if the wea-
ther prove clear and cold, the sulphate of magnesia, or
Epsom salt, crystallizes at the bottom of the coolers, in
quantity equal to about one-eighth of the boiled liquor.
The uncrystallizable fluid is then let off through plug-holes
at the bottom of the coolers; and the Epsom salt, after
being drained in baskets, is deposited in the store-house.
This is termed single Epsom salts, and after solution and a
second crystallization, it acquires the name of double Ep-
som salts. Four or five tons of sulphate of magnesia are
produced from a quantity of brine, which has yielded 100
tons of common, and one ton of cat salt.

On the banks of the Mersey, near its junction with the

#* ! am indebted for an account of this process, as well as of the method
«f making common salt at l.ymington, to the liberal communication of
Charles S;. Barbe, esq. of that place. Though not strictly connected with
the subject, I give his description of the mode of making Epsom salt, be-
cause no correct statement of the process has, I believe, been hitherto pub-
lished. The analysis of sea water, indeed, by a jur-tly distinguished chemist
(Bergman), excludes, erroneously, the sulphate of magnesia from its com-
position , and his results have led to the opinion, that to manufacture this
$alt on the iarge scale, requires the addition cither of sulphuric acid, or of
same sulphyfe to' the L-UUr liquvr. ("See Aikin's Chemical Dictionary, ii.

Irish

British and Foreign Salt. 1 1 1

Tvish Channel, the water of that river before evaporation
is brought to the state of a saturated brine, by the addition
of rock salt. The advantage of this method of proceeding
will be obvious when it is stated, that 100 tons of this brine
yield at least 23 tons of common salt, whereas from the:
same quantity of sea water, with an equal expenditure of
fuel, only two tons 17 cwt. of salt can be produced *.

Within the few past years, an attempt has been made to
apply rock salt itself to the packing of provisions. For
this purpose it is crushed to the proper size between iron
rollers. The trials which have been made, I am informed,
are but few, and the results hitherto are not perfectly
known.

Thcbaysalt imported from foreign countries is well known
to be prepared bv the spontaneous evaporation of sea vva^
ter, which, for this purpose, is confined in shallow pits,
and exposed to the full influer.ee of the sun and air. I
have no addition to make to the accounts of its manufac-
ture, which have already been given by various writers f.

As the results of the investigation, which forms the sub-
ject of this memoir, may be acceptable to many persons
who can scarcely be expected to take an interest in a long
detail of analytical processes, I shall present, in the follow-
ing section, a general view of the experiments, and of the
conclusions that may be deduced from them. In the last
place, in order that other chemists may be enabled to re-
peat the analyses under similar circumstances, 1 shall de-
scribe minutely the methods that were adopted, some of
which are rrew, and others reduced to greater precision.
If, however, in the future progress of science, it should
appear that any of these processes are imperfect, it may
still be admitted that, for all useful purposes, they afford a
fair comparison of the composition of the several varieties
of culinary salt ; since the sources of fallacy, that may
hereafter be discovered, must have been the same in every
case, and have produced in each an error of nearly the
same amount.

Sfxt. II. General Statement of the Results of the Experi-
ments, and Conclusions that may be deduced from them.

A comparison of the component parts of British and

* See the Earl of Dundonald'* * Thoughts on the Manufacture and Trade
of Salt." London, 1785.

•y Encvclop. Method, art. Salins. (Des Marais Salans) Aikin's Dictionary
of Chemistry, ii. 224. Watson's Chemistry, vol. ii. p. 52. It is necessary
to rem;irk, that a great proportion of what is sold in London as hay-salt is
Cheshire large-grained tishery salt. foreign

112 Analysis of Several Varieties of

foreign salts, and of different varieties- of British salt with
caeh other, will best be made by an examination of the
following table, which comprehends the results of the
analysis of equal weights of each variety,

1000 parts by weight consirt of

-A. __ . ______ ______

Kind of Salt.

"2 °

CO _.
B ■

^ a

9

1 _»

: .2 E
h —

i ^ <_.
< o

|a trace.

o .2

'i *.s

Total

earthy
muriates.

SJ

23/,

■ii

c _,

"a 2

CO c

4A

28

•- ._"

C 3

Pure
muri-
ate of
soda.

?c^ ( St. Ube's

3

*3

40

960

E >, \ St- Martin's

12

do.

•>i

*3j

19

6

25

i 40A

f}591

-<=j§ LOleron

10

do.

2

*2

19i

M

23|

^

964$

5 ^ /"Scotch (common)
. t? § £ j Scotch I Sunday)

4

1

___

28 or*

28 or*
HI

1.5
12

»7.

4',

32^
16 \

1 64.
29

$35.

971

pq "__ £ \ I.ymingtan(com.)
« 2 (.Do. (cat)

2

—

11

11 or*

15

35

50

63

937

1

—

5

5

1

5

6

12

988

o ( Crushed rock

10

°-,v

*tf

o*

6( -

*4

1^

983$

•jz «_ Nfr'ishery

1

fr*

ori

1

IM

—

nj

13$ 986$

S 5 j Common

1

P-4

o-.

1

14.

—

l 144

16£|9834

g (Stoved

1

o-4

o.|

1

I5|

—

15 i

1 17|

982*

I. The total amount of impurities, and the quantity of
real muriate of soda, contained in each variety of common
salt, may be learned by inspecting the two last columns of
the table. From these it appears, that the foreign bay salt
is purer, generally speaking, than salt whieh is prepared by
the rapid evaporation of sea water j but that it is contami-
nated with about three times the amount of impurities
discoverable in an equal weight of the Cheshire large-
grained salt, and with more than twice that of those that
are found in iht staved and common salt of the same district.

II. The insoluble matter in the foreign salt, after the
action of boiling water, appears to be chiefly argillaceous
earth coloured by oxide of iron, and is probably derived in
part from the pits in which the sea water is submitted to
evaporation. We may, perhaps, assign the same origin to
the very minute portion of muriate of lime, which is not
found in the salt prepared by evaporating sea water in me-
tallic vessels, nor even in the mother liquor, or uncrystal-
lizable residue. In sea salt prepared by rapid evaporation,
the insoluble portion is a mixture of carbonate of lime
with carbonate of magnesia, and a fine siliceous sand ; and
in the salt prepared from Cheshire brine, it is almost en-
tirely carbonate of lime. The insoluble part of the less
pure pieces of rock salt is chiefly a marly earth, with some
sulphate of lime. The quantity of this impurity, as it is
stated in the table, is considerably below the average, which
m my experiments has varied from JO to 45 parts in 1000.

Some

British and Foreign Salt, 1 13

Some estimate of its general proportion, when ascertained
on a larger scale, may be formed from the fact that Go-
vernment, in levying the duties, allows 65lb. to the. bushel
of rock salt, instead of 56lb., the usual weight of a bushel
of salt.

III. The earthy muriates, and especially that with base
of magnesia, abound most in salt which is prepared by the
rapid evaporation of sea water. Now since common salt,
in all its forms, contains, as will afterwards appear, very
little water of crystallization, it is probable that the muriate
of magnesia, discovered by the analysis of sea salt, is de-
rived entirely from that portion of the mother liquor
which adheres to the salt after being drained, and which
amounts to about one-seventh of its weight. The larger
the size of the grain, the less is the quantity of this solu-
tion which the salt holds suspended ; and hence the salt
prepared at a lower degree of heat, being in larger crystals,
is less debased by the magnesian muriate, than the salt
formed at a boiling temperature. It is probable, also, that
when the salt is drawn at intervals from the boiler, the pro-
portion of the earthy muriate will vary with the period of
the evaporation at which it is removed. For it may readily
be conceived, that as the proportion of the earthy muriates
in any brine is increased by the separation of muriate of
soda, the greater will be the quantity of the muriates which
the crystals of common salt, formed in the midst of the
brine, will retain ; thence it follows, that, so far as the
earthy muriates only are concerned, salt must diminish in
purity as the process of evaporation advances.

In the several varieties of Cheshire salt, the earthy mu-
riates do not exceed one thousandth part of this weight,
and they are precisely (or so nearly so that the difference
is not ascertainable) the same in all. This will cease to be
matter of surprise, when it is considered that the salt ob-
tained by evaporating to dryness the whole of a portion of
Cheshire brine, does not give more than five parts of earthy
muriates in 1000. In the entire salt of sea water, accord-
ing to Bergman, the earthy muriates form no less than 213
parts in the same quantity.

According to the proportion in which the earthy mu-
riates are present in any kind of salt, will be its power of
deliquescence, or of attracting moisture from the atmo-
sphere. It is not entirely, however, from the salts with
earthy base that common salt derives this quality ; for the
most transparent specimens of rock salt, which I find to

Vol. 36. No. 148. slugtist 1810. H consist

114 Analysis of several Varieties of

consist of absolutely pure muriate of soda, attract much
moisture from a humid atmosphere.

IV. The sulphate of magnesia and the sulphate of lime
both enter into the composition of all the varieties of salt
prepaTed from sea water; but the sulphate of lime alone is
found in Cheshire salt. The proportion of sulphate of
magnesia is greatest in that variety of sea salt which has
been formed by rapid evaporation. In foreign bay salt its-
quantity is very insignificant.

From the table \\ may be seen, that the proportion of
sulphate of lime is greater in foreign bay salt than in any
variety of British salt, even than in those which are pre-
pared from sea water with a boiling heat. The only ex-
planation of this fact, that oceurs to me, is, that during
the rapid evaporation of sea water a considerable part of
the calcareous sulphate is precipitated at an early stage of
the process, and is partly removed in clearing the boiler, a
process which can scarcely be performed during the for-
mation of bay salt, in pits whose sides are composed of
moist clay. The remainder of the selenite, thus precipi-
tated by the rapid evaporation of sea water, enters into the
composition of the pan-scale.

In the course of this inquiry I was induced to repeat the
same experiments several times, on various specimens of
salt bearing the same designation; and was surprised to
find that the results by no means corresponded. In one
instance, for example, fishery salt was found in 1000 parts
to contain no less then 16 parts of sulphate of lime; while
another specimen, nominally the same, contained only ll±
parts of selenite in the same quantity; and a third only 5±.
At length it occurred to me that these differences were
probably owing to the circumstance of the salt having been
taken from the boiler at different periods of the evaporation.
I requested, therefore, to be furnished with specimens of
salt, drawn at different stages of the process from a given
portion of brine, evaporated in the same boiler. These
were submitted to analysis; and the results are shown in
the following table.

Common salt drawn from the boiler two f •£ -
hours after the first application of heat . . } | 5

Salt drawn four hours after do ] | g

Salt drawn six hours after do L 2 2 J 2>\

Hence it appears that there was a gradually increasing

purity in the salt from sulphate of lime, as the process of

evaporation

British and Foreign Salt. 1 1 5

evaporation advanced, the greatest part of this earthy com-
pound being deposited at an early stage of the process.
Different specimens of the same kind of salt may, there-
fore, differ in chemical purity as much from each other as
from other varieties. But when the impurities contained
in a solution of muriate of soda are of a different species
from those of Cheshire brine, and consist chiefly of the
earthy muriates, the order will be reversed, and the purest
salt, as I have already suggested, will be that which is first
deposited, the contamination with the muriate of lime or
of magnesia continuing to increase as the process advances
to a conclusion *.

At an early period of the inquiry, it appeared to me pro-
bable thai the differences between the several varieties of
culinary salt might depend, in some degree, on their con-
taining variable proportions of water of crystallization. It
was found, however, by experiment, that the proportion of
water in any variety of common salt, after being dried at
2 12J Fahrenheit, is not much greater or less than that which
is contained in any other variety. Pure transparent rock-
salt, calcined for half an hour in a low red heM, ( = 4° or
5° of Wedgwood's pyrometer,) lost absolutely uothing of
its weight. It is remarkable, also, that the pure native salt,
if free from adventitious moisture, may be suddenly and
strongly heated, with scarcely any of that sound called de-
crepUationf, which is produced bv the similar treatment of
all the varieties of artificial salt. Even these varieties, how-
ever, exposed during equal times to a low red heat, do not
lose more than from half a grain to three grains in one hun-
dred. This comparison cannot be extended to the salt
prepared at a boiling temperature from sea water ; because
the muriate of magnesia which these varieties contain, is
decomposed at a red heat, and deprived of its acid.

* I cannot on any other principle explain the considerable differences, as
to the proportion of muriate of magnesia, that were discovered in the se-
veral varieties of Scotch salt sent tome hy Dr. Thomson. For this reason,
in seating the analysis of Scotch salt, I have given, in the table, that result
which was most frequently obtained; and have withheld the names of the
manufacturers, because the differences were probably in a great measure
accidental, and not the result of greater or less skill in the preparation. One
specimen of Lymington salt which I examined, contained fully as much
muriate of magnesia as any of the Scotch samples. The cat salt of that
place, however, contrary to my expectation, proved to possess a very ex-
traordinary degree of purity; a fact of vvlu'ch I satisfied myself by repeated
experiments.

f Decrepitation is occasioned by the sudden conversion into vapour of
the v.arer contained in salts, when its quantity is ir.sCiflicient to effect the
watery fusion. It is a property peculiar to salts which hold only a very
small proportion of water in combination ; as muriate of soda, nitrate of
lead, and sulphate of potash. H 2 The

1 16 Analysis of several Varieties of

The following; table shows the quantity of water con-
tained in several kinds of salt, inferred from the loss which
they sustain by ignition during equal times, after being-
first dried at 212°.

100 parts of large-grained fishery salt contain of

water 3

100 foreign bay salt (St. Martin's) .... 3

100 ditto (Oleron) S|

100 ^ . . . ditto, Cheshire common salt li

100 ditto stoved salt o£

The loudness and violence of the decrepitation was, as
nearly as could be judged, in the same order, and was most
remarkable in the large-grained varieties.

To determine the proportions of real muriate of soda in
those varieties of artificial salt which are nearly free from
earthy muriates, I employed also the process of decompo-
sition by nitrate of silver. The following are the quantities
of fused luiia cornea obtained from 1 00 grains of each of
three varieties dried, previously to solution, at the tem-
perature of 212° Fahrenheit.

100 gr. pure transparent rock s'alt gave of luna

cornea 24 2

100 . . . .stoved salt, remarkably pure 239

100 fishery salt. do 237*

The proportion of ingredients in the several kinds of
muriate of soda (setting apart the impurities) appears,
therefore, to be nearly the same in all. And as the very
minute quantity of water discovered by analysis is not
constant in the several varieties, it may be inferred to be
rather an accidental than a necessary ingredient; for in the
latter case an invariable proportion might be expected,
.conformably to the important law, establishing an uni-
formity in the proportions of chemical compounds, which
has been explained bv Mr. Dal ion, and confirmed by Drs.
Thomson and Wollaston.

What then, it may be inquired, is the cause of those

* From 100 grains of pure artificial muriate of soda, previously heated
to redness, Dr. Marcet has since informed me that he obtained 24*16 grains
of fused luna cornea. The weight^of the precipitates thrown down in my
experiments by nitrate of silver are not, I am aware, exactly those which
might have been expected from the table of the comparative proportions
of water given in the text. Each experiment, however, was twice repeated
with every precaution 1 could adopt, and with the same results. That dif-
ferent kinds of salt give different proportions of luna cornea, is proved also
by comparing the experiment of Dr. Marcet with the results of Dr. Black
and Klaproth, both of whom found the fused muriate of silver from 100
parts of common salt to weigh 2?>5 grains.

differences

British and Foreign Salt. 1 1 7

differences which are acknowledged, on all hands, to exist
among the several species of muriate of soda, so far as re-
spects their fitness for (economical purposes ? If I were to
hazard an opinion, on a subject about which there must
still be some uncertainty, it would be that the differences
of chemical composition, discovered by the preceding train
of experiments, in the several varieties of culinary salt, are
scarcely sufficient to account for those properties which
are imputed to them on the ground of experience. The
stoved and fishery salt, for example, though differing in a
very trivial degree as to the kind or proportion of their
ingredients, are adapted to widely different uses. Thus
the large-grained salt is peculiarly fitted for the packing of
fish and other provisions, a purpose to which the small-
grained salts are much less suitable. Their differenl powers,
then, of preserving food must depend on some mechanical
property; and the only obvious one is the magnitude of
the crystals, and their degree of compactness and hardness.
Quickness of solution, it is well known, is pretty nearly
proportional, all other circumstances being equal to the
quantity of surface exposed. And since the -surfaces of
cubes are as the squares of their sides, it should follow that
a salt whose crystals are of a given magnitude will dissolve
four times more slowly than one whose cube3 have only
half the size.

That kind of salt, then, which possesses most eminently
the combined properties of hardness, compactness, and
perfection of crystals, will be best adapted to the purpose
of packing fish and other provisions, because it will remain
permanently between the different layers, or will be very
gradually dissolved by the fluids that exude from the pro-
visions; thus furnishing a slow but constant supply of
saturated brine. On the other hand, for tiie purpose of
preparing the pickle, or of striking the meat, which is done
by immersion in a saturated solution of salt, the smaller-
grained varieties answer equally well; or, on account of
their greater solubility, even better.

With the hardness or strong aggregation of the several
varieties of salt, it seemed to me not improbable that their
specific gravity might in some degree be connected. The
exact determination of this property in saline substances is,
however, a problem of considerable difficulty, as will suffi-
ciently appear from the various results which have been
given, with respect to the same salts, by different experi-
mentalists. Thus Muschenbroek makes the specific gra-
vity of artificial muriate of soda to vary from 1918 to 2148,

H 3 the

1 18 Analysis of several Varieties of Salt,

the mean of which is 2033. Sir Isaac Newton states it at
2143, and Hasscnfratz at 2200*. All that was necessary
for my purpose was an approximation to the truth ; and
the introduction of a small error could be of no importance,
provided it were the same in every case, since the compari-
son would siill hold good.

The specific gravity of rock salt, there can he little diffi-
culty in determining with precision. A piece of this salt f,
1 of such perfect transparency that I had reserved it as a
cabinet specimen, weighed in the air 513 grains, and lost,
when weighed in alcohol, 194 grains. The alcohol, at the
temperature of 56° Fahrenheit, had the specific gravity of
820, and hence that of the salt may be estimated at 2170.
Another specimen 'considerably less pure, and more ap-
proaching to a fibrous fracture, had the specific gravity of
2125 only.

For ascertaining the specific weights of artificial varieties
of salts, T used a verv simple contrivance. It consisted of
a glass globe about 34- diameter,' having a stem or neck 10
inches long. Sixteen cubic inches of water (each 252|
grains at 60° Fahrenheit,) filled the whole of the globe, and
about half an inch of the lower part of the neck ; and from
the line where the water stood in the instrument, it was
accurately graduated upwards into hundredth narts of a
cubical inch. Into this vessel I poured exactly sixteen
cubic inches of a perfectly saturated solution of common
salt ; and then added 400 grains of the salt under examina-
tion, washing down the particles that adhered to the neck
by a portion of the liquid, which had been previously taken
out of the globe for the purpose. As much as possible of
the air which adhered to the salt was dislodged by agita-
tion, and the increase of bulk was then observed.

Care was taken that the salts were all of equal temperature
and dryness, and thai no change of temperature happened
during the experiment.

f 400 grains of the less pure kind of rock Hundredths *£*£*
salt, broken down into small frag- oi a - *n"grav.*ra»$

ments, filled the space of 75 2112

400 grains of stoved salt 75 2112

400 do. (another sample) 70 2084

400 do. common salt 76 2084

400 large-grained fishery salt 83 1 909

400 do. (another sample) 83 1909

400 St. Ube's . 82 1932

* Anvalrs de Chimie, vol. xxviii. p. 13.

f Foliated rock salt of Jameson. See his Mineralogy, vol. ii. p. 10.

\ -Distilled water at 1000 being taken as the standard. If

Description of a Metallic Thermometer. 1 19

If the above mode of determination at all approach to
correctness, it would appear that the specific gravity of
rock salt is diminished, by being broken into small frag-
ments, from 2125 to 2112, probably in consequence of the
quantity of air which the fragments envelop, and which
cannot be entirely separated by agitation. From the num-
bers given in the last column, it is evident that the smaller-
grained salts are specifically heavier than those which are
composed of larger and more perfect crystals. A difference
of only one or two hundredth parts of a cubic inch is
perhaps entitled, in a process of this kind, to little reliance;
and I do not therefore regard it as indicating any material
difference in the specific gravity of the first four or last
three salts submitted to experiment. But when the dif-
ference amounts to eight hundredths, as between the small-
and large-grained salt, it may safely be imputed to an in-
ferior specific gravity in that species, which occupies so
much greater a proportional bulk*.

The last series of experiments proves decisively, that in
an important quality, (viz. that of specific gravity,) which
is probably connected with the mechanical property of
hardness and compactness of crystals, little or no difference
is discoverable between the large-grained salt of British,
and that of foreign manufacture. If ho superiority, then,
be claimed for British salt as applicable to ceconomical
purposes, on account of the greater degree of chemical pu-
rity which unquestionably belongs to it, it may«safely, I
believe, be asserted that the larger-grained varieties are, as
to their mechanical properties, fully equal to the foreign
bay salt. And the period, it may be hoped, is not far di-
stant, when a prejudice (for such, from the result of this
investigation, it appears to be,) will be done awav, which
has long proved injurious to the interests and prosperity of
an important branch of British manufacture.

[To be continued.]

XIX. Description of a Metallic Thermometer for indicating
the higher Degrees of Temperature,

To Mr. Tilloch.

Sir, 1 beg leave, through the medium of your Magazine,
briefly to mention the principle of a new thermometer,

* M. Hassenfratz seems to have suspected that a difference in the specific
gravity of the same salt may be occasioned by a variation in its state of
crystallization. De la Pesanieur specify ue des Selst Ann. de Chim. xxviii. p. I7r

H 4 con-

120 Description of a Metallic Thermometer.

contrived by me, for the purpose of exhibiting the dif-
ference in temperature, or degrees of heat, which takes place
between the mercurial thermometer, the scale of which
terminates upwards, at 600°, and that of baked clay, or
Wedgwood's thermometer, the scale of which commences
at 1077° of Fahrenheit, or red-heat, thus forming an inter-
mediate or connecting thermometer between the two above
mentioned.

A metallic composition is formed, not liable to alteration
in its quality or quantity by repeated exposure to heat, the
melting point of which is at a little below 600° of Fahren-
heit, and its boiling point at 1200°. A case resembling
in form the glass case for the ordinary thermometer, but
somewhat larger, contains the metallic composition, and
the scale consists in a slender graduated rod, equal in
height at the commencement of the scale, that is when
the metallic composition is just liquid to the top of the
tube; the graduated rod terminating at the bottom in a
ihin, circular, fiat plate, which rests or floats as it were
upon the liquid metal; and in proportion as the latter exr
pands and rises in the tube bv heat, the graduated rod is
buoyed up, or raised above the top of the tube, passing
through a perforated cover to the maximum, or boiling
point*.

The same principle, I might observe, admits of being
extended, for the purpose or ascertaining the variation in
temperature up to the most intense heat, perhaps, that can
be required.

It is unnecessary to state here, that the influence of the
incumbent atmosphere upon, the surface of the liquid me-
tal within the open tube is too inconsiderable, even at the
commencement of the scale, to deserve notice, and at a
higher temperature diminishes to nothing; especially if
the whole of the liquid contained in the thermometer, as
ought to be the case in the use of every thermometer , be
completely immersed or subjected to the temperature, the
degree of which it is intended to indicate.

A method similar to the above, I should think, might
be applicable to the purpose of showing in a ready way the
degree of expansion in metals bv heat ; but the elongation
of a cylinder of any metal, by increase of temperature, is

* The thermometer case and graduated rod arc at present formed of
pipe-makers' clay previously prepared by having been exposed to a suffi-
cient degree of heat.

The scale of this new thermometer is an exact continuation of the scale
in the mercurial thermometer; the lower degree of the former correspond-
ing with, or indicating like temperatures with, the upper degrees of the
mercurial thermometer. much

On Cry st allograph]/, 121

much too small to admit of its being a convenient measure
of temperature.

I should not despair, however, (availing myself of every
advantage, viz. increasing the length of a metallic wire,
by giving it a spiral form, in order to comprise a consi-
derable length in small compass ; with the application of
the lever-index, and a good magnifier.) of constructing a
thermometer upon this principle, so as to render the scale
apparent even to single degrees; using silver for the lower
temperatures, and platina for the higher, or employing
iron wire, only up to its ultimate point of expansion in a
solid state *.

I am, sir,

Your obedient servant.

Queen-street, Oxford, PvICHARD WALKER.

Aug. 6, 1810.

XX. On Crystallography. By M. Hauy. Translated
from the last Paris Edition of his Traite de Mineralogie.

[Continued from p. 69.]

THEORY OF THE LAWS TO WHICH THE STRUCTURE OP
CRYSTALS IS SUBJECTED. GEOMETRICAL PART.

Preliminary Notions,

1. JL he theory which I here propose to submit to calcu-
lation has for its object, to determine all the different forms
which may arise from a superposition of decreasing laminae
following known directions and laws, on the various faces
of a solid, the figure of which is also given f.

2. The solid which I call nucleus or primitive form is
always one of the six following: 1st, the parallelopipedon;
2d, the regular hexahedral prism ; 3d, the rhomboidal
dodecahedron; 4th, the octahedron ; 5th, the tetrahedron,
which in this case is always regular; 6th, the bipyramidal
dodecahedron.

3. By subdividing each of these solids parallel to its dif-
ferent faces, and sometimes also in other directions, we
obtain the integrant molecules, which are aKvays either
parallelopipedons, triangular prisms, or tetrahedrons. <

* For the means of rendering exceedingly minute divisions distinct, see
a. method described in the Monthly Magazine for May 1810.

f I presume that my readers are acquainted with that part of my treatise
jn which the same theory is detailed by simple reasoning. I shall there-
fore now confine myself to resuming in a succinct manner the most general,
principles of this theory.

4. When

1C2 On Crystallography.

4. When the nucleus being a parallelopipedon is divisi-
ble only by planes parallel to its six faces, it is evident that
the integrant molecule is itself a parallelopipedon similar
to this nucleus.

5. But even when the integrant molecules differ from
the parallelopipedon, thev are always situated in the interior
of the nucleus, in such a manner that being taken by small
groups they compose parallelopipedons ; and the decre-
ments which give the secondary forms are always made by
rows of these parallelopipedons as in the case first men-
tioned.

J give the name of subtractive molecules to the small
parallelopipedons, divisible or not divisible, the subtraction
of which determines the decrements of the laminae of su-
perposition.

It follows from what has been said, that the subtractive
molecule is a kind of unity, to which we may refer the
structure of all crystals in general, so that we are at liberty
to adhere to the data which it furnishes in the application
of calculation to every possible crystalline form. To know
afterwards if this unity be indivisible, or if it has fractional
parts,is a matter of observation which maybe interesting in
natural history, but independent of which the theory would
not admit of our proceeding towards the object in view.

6. In the case where the nueleus itself differs from the
parallelopipedon, we may always substitute for it a solid
of that form, either by abstracting from some of its faces,
if there are more than six, or by multiplying the subdivi-
sions alwavs in the direction of the natural joints, if it be
a tetrahedron. But we frequently obtain more simple re-
sults, by giving the preference to the true nucleus.

7. The decrements undergone by the laminae of super-
position may be effected in all imaginable directions. The
limits of these directions are the edges and the diagonals of
the faces of the nucleus. Between these two limits there
is an infinity of intermediate ones, according as the small
solids, the rows of which determine the quantity of the de-
crements, are considered as double, treble, quadruple, &c.
of the subtractive molecule. I call decrements on the edges
those which takq,, place parallel to the edges of the faces
of the nucleus ; decrements on the angles, those which take
place parallel to the diagonals ; and intermediary decre-
ments, those which are made parallel to lines comprehended
between the edges and the diagonals.

I shall now successively treat of the different primitive
forms above mentioned, and give, relatively to each of them,

the

On Crystallography. 123

ihe method of calculating the results of all the laws of de-
crements of which it is susceptible. I shall begin with
the parallelopipedon, which is as it were the term of com-
parison to which the other forms refer.

1 . Theory of the Parallelopipedon.

8. Let AG (fig. 1, PI. IX) be a parallelopipedon, the faces
of which may have whatever respective dimensions and
measurements of angles we please. Let us conceive this
solid subdivided, by plans secting parallel to its different faces,
into a multitude of elementary parallelopipedons which
will be the integrant molecules. Each of the same faces
will be separated in its turn into a certain number of small
parallelograms, which will be the exterior faces of as many
molecules.

If we choose any two of the six faces in question, pro-
vided they are opposite, we may consider the solid as an
assemblage of lamina? distinguished by the secting plans
parallel to these very faces.

9. Let us now imagine pew laminae formed of small
parallelopipedons similar and equal to the foregoing, which
are placed as if in steps above various faces of Ihe generator
parallelopipedon, in such a manner that the facets in con-
tact coincide exactly, like what takes place in the interior
of this solid. Here there are three cases to be distinguished.
The first is that in which the laminae extend by their edges
so as to envelop completely the generator parallelopiptvion,
which wilf grow without changing its form. The second
is that in which the laminae would remain on a level by their
edges with the faces adjacent to the generator parallelopipe-
don, in which case it is easy to see that thev would form
re entering angles at the places of the ridges DC, BC, CG,
&c. In the third case, the laminae will go on decreasing,
following certain directions, in such a manner that each
will be exceeded by the foregoing in a quantity equal to
one or more rows, either in breadth or height.

Of thee three cases, the first is relative to the primitive
forms given immediately by crystallization, and admits of
no difficulty. The second is foreign to Our views, because
nature presents us with no exampleof it in simple crystals.
We shall dwell at some length upon the third, which is.
properly the object of the theory.

10. Let us conceive in the first place that the decrements
are produced in breadth on all the ridges by subtraction of
an equal number of rows, and let us confide ourselves for

the

124 On Crystallography.

the moment to the consideration of the effect of the de-
crement which takes place parallel to the ridge BC,
ascending above the parallelogram A BCD.

If we suppose that the form of the integrant molecule
which is similar to the generator parallelopipedon is deter-
mined, and that the law of decrement is known, it will be
easy to find the angle formed with ABCD by the face pro-
duced in virtue of This decrement.

Let a g (fig. 2) be one of the molecules, of which the
faces analogous to those of the parallelopipedon, fig. 1, are
marked with the same letters. From the point c I draw
cs and cr perpendicular on h c. Now, by the hypothesis,
the relation between these two lines is given, as well as the
angle res which measures the incidence of abed upon
b c g h.

Now let op (fig. 1) be the distance between the ridge
BC and the first lamina of superposition, which distance
is regarded as being measured on the plane ABCD. It is
clear that op is equal to c r (fig. 2) multiplied by the num-
ber 7? of rows subtracted. Therefore op = n xcr. From
the point p (fig. 1) raise pu lying upon that of the lateral
faces of the first lamina, which is turned from the same
side, and equal to the height of this face. We shall have
puz=cs (fig. 2) and opu = scr. Complete the triangle
upo (fig. I). It is visible that the line ou will coincide
with the face of the secondary crystal, which rises on the
ridge BC, and that the angle pou will measure the inci-
dence of this face on the parallelogram ABCD. Thus,
since in the triangle up 0 we know the two sides op, p u,
and the comprehended angle opu, it will be easy to get
the angle pou which gives the incidence wanted.

] 1. The triangle p ou is caFled mensurator triangle ; and
1 shall subsequently give this name to all the triangles
which perform the same function.

12. Let us now consider the effect of the decrement
wtirch takes place parallel to the same ridge BC, by de-
scending on the face BCGH. Let 0 ik be the mensurator
triangle, in which 0 i is the distance between the ridge
BC and the first lamina of superposition, ill coincides
with that of the lateral faces of this lamina, which looks to-
wards the ridge BC, and besides it is equal to the height
of the face in question; finally, oh is laid on the face
which results from the decrement.

Let w' be the number of rows subtracted. We shall
have oi (fig. 1,) = n' xcs (fig. 2). Also ill (fig. 1) = cr

(fig-

On Crystallography, 125

(fig. 2), and oilier cs. Thus it will be easy to determine
the ancrle which the face produced by the decrement forms
with BCGH (fig. 1 )

13. It may happen that the two decrements which act
on both sides of the ridge BC have such a connexion
with each other that the two faces which will result from
them will coincide upon one and the same plane, so that
the side oh of the triangle oih is upon the direction of
the side ou which belongs to the triangle upo, as we see
in fig. 3. . To prove this, we may remark, that in this
case the triangles upo, oik are similar, as well on ac-
count of the equality of the angles op u, hi o, and the pa-
rallelism of the sides op, i h, as on account of the coinci-
dence of the sides ou, ho upon one and the same direction.

Therefore pu : op : : oi : ill.

Or rather cs (fig. 2) : n x cr : :n' x cs : cr.

Which gives n' = — .

That is to say, the case in question will happen every
time that the decrements which take place on proceeding
from BC towards GU are in the inverse ratio to those
which take place in going from BC towards AD, or, what
comes to the same thing, at all times when there is on one
side a decrement in height equal to that which shall be on
the opposite side. We may easily conceive that the two
faces will be still on one and the same plane in the peculiar
case of a decrement by one row on both sides.

14. Hence we may conclude, that in all circumstances-
similar to those which have been cited, we may make abs-
traction of one of the two decrements, by considering the
face which results from it as the continuation of that which
arises from the other decrement.

We see what would have been necessary for determining
in a similar way the incidences of the faces produced by
the other decrements upon the analogous faces of the
generator parallelopipedon.

15. The greatest number of faces which the secondary
solid can have, is twenty-four, since the generator parallelo-
pipedon has twelve ridges, each of which is the line of
departure of two decrements which act in an opposite direc-
tion. These faces will all be triangles, or some triangles and
others trapeziums, according as the generator paralielopipe- ■'
don will be found more elongated in one. direction than in
the other, or as the decrements which will take place pa-
rallel to certain edges will follow a more rapid course than
those which would act parallel to other edges.

The

126 On Crystallography.

The smallest number of faces which the secondary cry-
stal can have is twelve. Then all the decrements consi-
dered two by two, setting out from one and the same ridgey
v. ill be inverse to each other.

The simplest case is that in which the generator parallelo-
pipedon being a cube, we have n— i and //— l. On this
•hypothesis, the secondary solid is a dodecahedron with
rhombic planes all equal and similar, as we have explained
m the reasoning part of the work.

16* We now proceed to the method of determining the
decrements upon the angles. But we mav previously re-
mark, that in this case the decreasing parts of the lamina?:
of superposition form angles alternately re-entering and
salient^ in Stteb a way, however, that all the ridges of mo-
lecule situated at the places of the salient angles are on
one and the same plan : we shall consequently designate
the series of these ridges by the name of lateral face.

This being done, let us conceive that decrements in
breadth are produced by equal numbers of rows on all the
angles of the parallelopipedon, fig. 1 ; and let us take for
instance that which takes place upon the angle BCD.
Let Ckl be the mensurator triangle, in which C/e measures
the distance between the point C and the first lamina of
superposition, kl is regarded as being applied on the cor-
responding lateral face, the height of which it measures,
and C / coincides with the face of the secondary crystal,
produced by the decrement in question.

Having traced the diagonals db,fh (fig. 2) on the
bases of the molecules, I draw ct perpendicular upon d b,
and x% perpendicular as well upon db as upOQ\fk,

Let N be the number of rows subtracted. We shall
have Ck (6g..l) ssNXcf (fig. $}, and k I (fig. 1) = x z
(fig. 2); besides the angle Ckl (fig. l) will be equal to
that formed by the plane bdfk (fig. 2) with fgh. Now
these three quantities are regarded as being known, since
the form of the molecule is determined. Thus it will be
easy to find the angle kCl (tig. l) which measures the
inclination of the face produced by the decrement upon
the parallelogram ABCD. We shall conduct ourselves in
the same manner in order to calculate the effects of the de-
crements on the other angles.

17. Let us now consider the hypothesis in which the
decrements which take place on the two angles DCG,
BCG would have such a connexion with that which acts
on the angle BCD, that the faces produced by these three
decrements would coincide on one and the same plane.

Let

On Crystallography. 1 27

Let AG (fig. 4) always be the generator parsllelopipedon.
Suppose that the decrement which takes place in breadth
upon the angle BCD has such a measurement, that the
lower edge of the first lamina of superposition passes by
m r, in which case such of the lines Cm, Cr will contain
as many ridges of molecule equal to c d, or cb (fig. 2), as
there will be rows subtracted by the decrement. Having
taken upon CG (fig. 4) a part Cc equal to eg (fig. 2),
make a plane pass by the points m,c,r. / say that this
plane is parallel to the face which results from the decrement.
In order to prove it, having drawn indefinitely the lines
m s and ru parallel to CG, I prolong them each upwards,
so as lo have him, or Rr equal to Cc. Now these pro-
longations M m and R r represent two of the ridges situated
on the lateral face of the first lamina. Therefore the face
produced by the decrement passes by the points M, R. But
besides it passes by the point C, which is the term of de-
parture of the decrement; therefore the plane MCR coin-
cides with it. Now the small lines Cc, M?n, Rr, being
three longitudinal ridges of molecule, situated parallel to
each other between the two planes mcr, MCR, it is visible
that these two planes are themselves parallel, i.e. that mcr
is parallel to the face which arises from the decrement.

The same reasoning applies to the hypothesis in which
the decrement should take place in height. In this case it
would be necessary, in order to make the, plane mcr be
parallel to the face produced, that we should have cm — cd
(fig. 2) ; cr=:cb', and that the line Cc (fig. 4) should
contain as many times eg (fig. 2) as there would be ranges
subtracted in the direction of the height.

18. Let us suppose that the plane MCR is prolonged
above the faces CDFG, BCGH, and consider the pro-
longations as two faces which would be the effect of two
decrements, the one upon the angle DCG, the other upon
BCG. These decrements being equal, we shall confine
ourselves to that which acts upon the angle DCG. Since
the plan cmr is parallel to the face which results from
this decrement, it is clear that cm coincides with ttie
lower edge of the first lamina of superposition applied
upon CDFG, and that Cr contains as many ridges of
molecule as there are ranges subtracted in height.

1Q. If the decrement relative to the angle BCD takes
place by one row, it is evident that the two other decre-
ments relative the one to the angle DCG, the other to the
angle BCG, will also take place by one row : since then the
three lines Cm, Cr, Cc, are equal each to one ridge of

molecules,

12S On Crystallography.

molecules, the three decrements must necessarily hare the
same measurement.

20. But if the decrement relative to the angle BCD is
produced by more than one row, then the two others will
necessarily be intermediate, and it will be sufficient to have
the law of the first decrement for determining the two
others. Let us suppose, for example, that the decrement in
the angle BCD is made by three ranges in breadth. In
this case Cm and Cr will each of them he equal to three
ridges of molecules, and C c will be equal to one ridge.
Therefore the decrement on the angle DCG is produced in
such a manner that there are three ridges of molecules sub-
tracted in the direction of CD, upon one alone in the direction
of CG; and besides this decrement is made by. three rows
in height, since Cr answers to three ridges of molecules,
it is the same with the decrement which takes place on the
angle BCG.

21. In all cases of this description, the theory only con-
siders the effect of the decrement which takes place accord-
ing to the ordinary laws, because there results from it a
much more simple solution; and the two other decrements,
of which abstraction has been made, are considered as in-
tervening in a subsidiary manner to second the effect of
the first, and prolong towards the parts adjacent the face to
■which it has given birth.

-22. The greatest number of faces which the secondary
crystal can have, in the hypothesis of a decrement on all
the angles, is twenty-four, since there are eight solid angles
each composed of three plane angles, which are the terms
of departure of as many decrements. The minimum of
the number of faces in the same hypothesis is eight; and
although strictly speaking there are always twenty-four de-
crements, we only consider eight, which gives us the fa-
cility of employing ordinary laws only, for determining the
form of the secondary crystal.

23. The simplest case is that in which the generator pa-
raliclopipedon being a cube, all the decrements are done by
one row. The secondary solid isthen a regular octahedron.

But it may happen that the three decrements which take
place around one and the same solid angle are all inter-
mediary. In this case it is sufficient that one of them be
determined, in order to render it easy to conclude from
thence the two others, by the help of a construction similar
to that which we have previously employed.

24. Let us suppose that fig. 5 represents the. generator
parallelopipedon, marked with the letters relative to the

method

On Crystallography. 129

method of indicative signs. Let us conceive that there is
made upon the angle O, ascending, a decrement which pro-
duces a face parallel to the plane n r s, and the expression

of winch is (OD*F4), whence it follows that on = 3crf
{fig. 2), Or = 4cb, and Os= Qcg.
This being done, the expression of the decrement on the

left of the angle O will be (^ODJ H2), and that of the de-
crement to the right of the same angle (0TF4 H>).

25. Tn order to determine the angles formed by the faces
produced by the intermediary decrements with the corre-
sponding faces of the nucleus, what presents itself as the
simplest is to consider every little group of molecules,
which results from the decrement, as forming one single
molecule ; which brings back the calculation to that which
is employed for the ordinary decrements on the angles.

Let us take for example the decrement on the angle O
i
ascending, represented (OD*F4). Tt is easy to judge that
in this case, the group which represents two subtractive
molecules placed the one above the other, is that which we
sec fig. 6, and in which the side mn is composed of three
ridges of molecule, the side np of four ridges, and the
side nk of two ridges, on account of the decrement by
two ranges in height.

Having traced on the bases the diagonals mp9 i o, I
draw vt perpendicular upon wp, then us perpendicular as
well upon mp as upon io.

Let n ty (fig. 7) be the mensurator triangle, in which
nt being regarded as lying on the plane AEOE (fig. 5)
will be equal to the same line (fig. 6). Besides, we shall
have ty (fig. 7) = u s (fig. 6), and the angle nty (fig. 7)
will be equal to that formed by the plane mpoi (fig. 6)
with the triangle i k o. Thus it will be easy to find the
angle yn t (fig. 7) which measures the inclination wanted.

26*. The solutions of problems of this kind are often sim-
plified in practice, by a series of the regular form of mole-
cules. Let us suppose, for example, that the latter are
cubes. Let us designate each of their ridges by unity.
We shall have (fig. 6) m n = 3, np = 4, nk = 2, mp =

V (mn)1 + hip)1— V 25 = 5. nt — = ---.«$ = 72 A = 2.

x ' v r/ rnp 5

Thus also nt (fig. 7) = -7-, ty = 2.
Vol. 36. No. 148. August 1810. I Thus

130 On Crystallography.

Thus n I : t y : : ~ : 2 : : 6 : 5. Besides, in this same

case, the angle v t y is straight ; from which we see how
easy it is to find the angle y n t.

£7- The mensuralor triangles relative to the decrements
on the angles may be substituted for those which we have
considered in the decrements on the edges, and serve
equally well for determining the secondary forms. Let us
suppose, for example, that AG (fig. 8) represents a cubical
nucleus, which undergoes decrements by two ranges on
the four edges of the base A BCD, and that we wish to
know the angles of the pyramid SADCB produced by this
decrement. Having traced the diagonals BD, AC, I draw
from their point o of intersection the line op perpendicular
upon CD, then sp. If I take upon po the part, pr equal
to two ridges of molecule, and from the point r I raise r u
perpendicular upon A BCD, and which by the hypothesis
will be found equal to one ridge of molecule, the triangle
upr will perform the function of the ordinary mensurator
triangle, and by means of the right angle urp, and of the
relation 2: 1 between the sides pr and ur, we shall easily
find the incidence of DSC upon the base ABCD, as well
as the values of the other angles. For, on account of the
similar triangles u pr, spo> every thing is reduced to the
calculation of the a?igles of a straight pyramid in which
the side BC of the base, which is double of po, is to the
axis os in the relation of 4 to 1.

On the other hand, — If I take upon Co the part Cn
equal to two diagonals of molecule ; and if from the point
n I raise nz perpendicular upon ABCD, On will represent
the distance from the point C to the fust lamina of super-
position, taken in the direction of Co, and nz will be
equal to one ridge of molecule; from which it follows that
the triangle z C n may also perform the function of men-
surator triangle.

We shall therefore have Cn : nz : : -2 v72 : 1, and be-
cause the triangle zCn is similar to the triangle .?Co, the
question considered under this new point of view will be
reduced to seek the angles of a straight pyramid, in which
the demi-diagonal Co of the base is to the axis os, as
2 s/ e~: 1, which is sufficient for having all the rest. We
shall have occasion more than once thus to substitute one
mensurator triangle for the other, when there will result
from it more facility in resolving the problems.

All the details upon which we have acted ought to be

regarded

On Cupping. 131

regarded as preliminary notions intended particularly to
enable students clearly to understand the use of the men-
surator triang'cs which will incessantly recur in the ap-
plications which we shall make of the calculus to the
laws of decrements. We shall now proceed more particu-
larly to the methods relative to this object; and as the
rhomboid, which likewise comprehends the cube, is of all
the kinds of parallelopipedon the most fertile in diversified
results, and at the same time that which is the most easily
adapted to the employment of general formulae, we shall
first give the theory of this solid ; after which we shall re-
sume that of the parallelopipedons of a different form.

%* Understanding that an English Translation of the whole of Mi-.Hauy's
valuable work on Crystallography is now preparing for the press, we in-
tend, for the present, to suspend our labours upon it, as a full translation
cannot fail to answer the object we had in view, ^better than those disjoined
portions which can alone be admissible into the pages of a p6riodical work.
— Should the propo.scd translation not appear in some reasonable time, we
may hereafter resume our labours.

XXI. Dr. Healy on Cupping.
To Mr. Tilloch.

I No. 1, Clarendon-street, Dublin.

hequest you will permit me to contradict an ob-
servation which has been made, in the Retrospect of Dis-
coveries, stating that the mode which I propose for cup-
ping without the assistance of the syringe, is so far from
new, that it occurred nearly £000 years ago, to Hero of
Alexandria, and that the figure is exhibited in the Maiht-
matici Vetercs.—l consulted the Parisian edition, and fiud
his contrivance (as described page 207) entirely different
from mine. Suffice it to say, a partial exhaustion is pro-
duced by the mouth from a secondary cavity, and two stop-
cocks are made use of. The syringe, which is an improve-
ment, and answers for the secondary cavity of Hero, is the
usual mode at present of producing the vacuum, and not, as
the observer states, the spirit lamp or tow. The apparatus
which I propose will still, I imagine, be found new, more
teconomical, and less complicated, than any that has been
hitherto adopted.

Your much obliged,

My i9, i8io. Robert Healy, M.B.

I 2 • XXII. Obser-

t 132 ]

XXII. Observations on the Purity of Standard Gold. By
M. Fabbroni, of Florence, corresponding Member of 'the
French Institute, To which are subjoined Notes by
ili. D'Arcet, Assay Master of the French Mint*,

Almost all naturalists (following perhaps implicitly the
assertion of Pliny t) maintain that native gold is never
found pure; i.e. entirely free from alloy, chiefly of silver,
and that the finest is scarcely from 0*575 to 0*917, or 21 or
22 carats. The gold iu dust, in spangles, or in sand, which
is brought from Africa, is most frequently within these li-
mits. I have seen some gold from the country of Barn-
buck in Africa, which was 0*927, or 22 carats and one-
fourth -, in the mint of Florence it has also been seen at
0*958, or 23 carats -. this gold had been brought from
Morocco. The carat in Tuscany is divided into eighths.

It is probable that in the early ages money was coined
with native gold, in the state in which it was found, there
being no grounds for supposing that they took pains to
refine it.

It has been thought that the oldest gold coin known is
that of Battus IV, which was melted or struck at Cyrene
in Africa in the time of Pisistratus : it does not appear that
the standard of this gold was known. Of all the Grecian
coins which are in the hands of the collectors of medals,
the most ancient are the beautiful pieces of Philip the fa-
ther of Alexander. That enterprising man, who from his
infancy conceived the idea of ascending the throne of
Macedon, and becoming master of Greece, was fortunate
enough to find several rich mines of gold, which he knew
how to prize. Mount Pangea annually furnished him with
gold to the amount of 5,22p,000 francs, and from thence
he derived the most powerful resources for the success of
his political designs and military talents. It is not known
whether this metal of Philip's underwent any particular
operations before parsing to the mint. There are some

* Annates de Chimie, tomehxti. p. 25.

f Pliny says, lib. 33, that there is »o kind of gold more perfect than
spangle gold » that gold obtained by searching the beds of rivers does not
require melting, and that it is native and perfect gold. But Pliny says in
the same book that lead is more malleable and heavier than gold ; which
proves that the gold which he regarded a? pure was in reality an alloy.
He says likewise a little further on, that all gold is mixed with silver, and
that the gold which is the least alloyed with silver camefrom Albicratum
in Gaul, and that it contained only Jd. From all this it is evident that
Pliny's opinion is not to be followed, Mil recourse must be had to experi-
ments.

grounds,

Observations on the Purity of Standard Gold, 133

grounds, however, for thinking that it was used in the state
in which it was found.

Patin assayed a statera of gold of this king (the deno-
mination of his coin among the Persians and Macedonians),
and found it to he 23 carats and a half, or 0*970. We
cannot allow ourselves to believe that the metallurgists of
that monarch thought to purify gold by adding to it only
a 4Sth part of alloy, but we can easily suppose that the gold
was found in this state of fineness.

If alloys were added to gold from a bad design, or with
the mistaken idea of covering the expense of manufacturing
it; this has degenerated into fraud, and has no limits; if
the alloy was added with the view of ^making the money
harder, it was a futile attempt. Neither of these motives
could sway with Philip, because he enjoyed abundant mines
of gold, and because, as he wished to appear generous, he
would have made his coin of pure gold, if he thought it
necessary to refine it : or he would have added more alloy,
if policy suggested that he should not employ it as it came
from the bowels of the earth *. It should seem, therefore,
that his mines furnished him with gold at 23 carats and a
half (0*979)> as it is found to be in his coins, if there be no
error in Patin's analysis : but it might perhaps be interest-
ing to confirm this fact by a new experiment.

Chevalier Fossombroni, an eminent mathematician, in
digging the foundation of a house near Arezzo, found a
statera of Philip in good preservation, which he was kind
enough immediately to give us to be examined by analysis.

On one side of this piece, as in most of Philip's coins,
there is a head of Apollo, and on the reverse a car with two
liorses : the name is on the exergue : — on similar coins we
see under the legs of the horse a monogram or type indi-
cating the mint where the coin was struck. On the piece
in question there was a trident, which means Trcezene.

Fourteen of these coins are preserved in the cabinet of
the Florence gallery : the face and the reverse of eleven of
them are similar to that of Arezzo ; but they have various
distinguishing marks, one only bearing the same mint-mark

* I transmitted to M. Mongez the analysis of an ancient coin with the
effigy of Philip: its examination also proved, that under the reign of that
prince alloys were used in the making of money, the composition of which
was natural, or at least unknown; for it contained silver 368, gold 184,
copper 448.

It is not likely that so complex an alloy would have been used at a pe-
riod when the modes of analysis were so little known, as to fall far short of
the degree of exactness which may be attained even by employing the
touchstone and prepared acid now in use.

I 3 with

134 Observations on the Purity of Standard Gold,

with that found at Arezzo. The weight of two of these,
completely similar in external appearance, was precisely 176
grains of Florence each. The same weight was found in
another distinguished by a monogram formed by a large K,
and a little o ; the same weight in another which had a
thunderbolt; the same in another with a vase; and lastly,
in another with a grain of wheat, the mark or' the Leontini.
These six weights or' the largest staterae which remain, and
which are equal, gave grounds for concluding that the
above was the weight prescribed for the Greek money.
This being granted, we may infer that the drachma weighed
88 grains. (Koine de PJsle assigns three grains more to
the great Attic drachma.) The proof of the accuracy
of this calculation is to be found in the Athenian demi-
drachma, or x\siatic drachma, or the fourth part of the
statera of Philip, which is preserved in the same gallery :
this fragment weighs precisely 4-J- grains. The face of this
small piece of gold presents the head of Hercules covered
with a lion's skin, and on the reverse we see the bow, the
vase, and club. M. JMillin has communicated to me the
weight of five staterae preserved in the Imperial library,
which are as follow : No. 1. 160*5 grains ; No. 2. 1(3 1 grains
precisely; No. 3. 1 6 1 grains; No. 4. 162 grains precisely;
No. 5. 16-2 grains. The two heaviest seem to be so from
having bf en less worn. The largest would answer to 175-16
grains of Florence, and would be lighter by gr. 0*84 than
ours, which ought therefore to be regarded, as less worn
and more precise.

Mr. Greaves, in England, weighed two staterae of Alexan-
der, one of which was 133 English grains, and the other
133 and a half. He thought that the half-grain had been^
wasted by friction, and he concluded that the drachma
ought to be reputed as being precisely at 67 grains. The
second weight as given by Mr. Greaves would be equivalent
to 87 grains and six-tenths of Florence. Snellius found the
statera of Philip and of Alexander to weigh 179 Dutch
grains, which makes 124 and a half English; and this, ac-
cording to the foregoing comparison, would give to the
drachma in Florence weight 87 grains 0 Q ; all of them be-
ing a little lighter, but closely approaching that which we
had fixed at 68 grains.

Barthelemy, in France, found after various weighings
that the drachma was precisely 81 French grains and an
eighth : now, by the foregoing comparison, we ought to
have for the drachma in Florence weight 87 grains and
three* fourths. But this last author wishes to suppose a

friction

Observations on the Purity of Standard Gold, 135

friction of se/en -eighths of a grain for 2,200 years wearing,
and he gratuitously makes the drachma to he 82 whole
French grains, which would make 88 and a half of Florence
weight. It is best to banish entirely from our calculations
all suppositions of friction, because, by admitting this to
have been the case, we might draw a variety of vague con-
clusions. The weight of 88 grains which we have assigned
to the gold drachma is confirmed by a silver one of this
very Philip, also preserved in the Florence cabinet: this
piece has on its face the head of Hercules without a beard,
covered with a lion's skin ; and on the reverse a Jupiter
sitting, holding the eagle in his right hand and a spear in
his left. It is distinguished from the others by a lyre, and
the letter A under the seat. This drachma is also a proof
of the exactness of its weight in its half, also in silver,
of the same king, which weighs precisely 44 grains : on
its face is the head of Jupiter with the diadem ; on the re-
verse is a figure on horseback, with the name on the exergue
and a mark which is unintelligible. Besides, there are four
pieces of four drachmas of Alexander of the same metal,
the face and reverse of which are similar: all of these weigh
14 pennyweights and 16 grains, and prove completely that
the weight of the drachma is 88 grains. These tetra-
drachmas are distinguished in the type by the addition of
various signs, as we have said with respect to the staterce :
one has in front a lamp, and under the seat a moon and a
star: another has in front the letter T with a circumflex
accent, and under the seat the letter K : another has in
front a buckler, and under the seat a serpent : the fourth
has in front a crown, and under the seat a monogram com-
posed of M. Finally, we have also a real drachma of this
king of the precise weight of 88 grains, and which is di-
stinguished by a monogram formed by an II, the cross bar
of which has a kind of circumflex accent.

Among the tetradrachmas of Thrace there is one in the
Florence collection, and the twelfth of the list, heavier
than the rest; it weighs precisely 14 pennyweights and 16
grains: here we have a proof of the identity of the weights
of the Thracians and Macedonians, as long ago supposed
by the learned.

After the weighing of the Arezzo coin was finished, it
was submitted to the cupel and to quartation. The stand-
ard was found to be the same with Ruin's examination, i.e.
0'9"9> or 23 carats and a half: it contained only half a
carat, or 0.021, of silver.

The art of assaying was known in the earliest times, as

1 4 attested

136 Observations on the Purity of Standard Gold,

attested by the Holy Scripture : we find it at such adegree
of perfection even in the time of Pliny *, that by means
of it the standard of gold was fixed at 21 carats, or 0*875,
at SI carats and 7-24ths (0888) up to 23 carats and
ll-32ds (0*973). In those days they must have assayed
in the dry way, first by separating from the gold the viler
metals by means of lead, and afterwards even the silver,
with sulphur or with the sulphurets f.

They were also acquainted with the method of refining
and purifying gold in large quantities, by cementing or
burning it, as Strabo informs us, with an aluminous earth,
which by destroying the silver left the gold in a state of
purity. Pliny says that for this purpose they put the gold
on the fire in an earthen vessel, with treble its weight of
salt ; that it was afterwards again exposed to the fire with
two parts of salt and one of argillaceous sclustus: this would
surely effect the decomposition of the salt, and the volatili-
zation of the muriatic acid in a state of ignition and dry,
which would penetrate the substance of the gold, and wouid
separate the silver in the form of volatile muriate: this is
the object of the process of cementation among the mo-
derns J. But Agatharchides has transmitted to us a peculiar
method practised in the mines situated between the Nile aud
the shores of the Red Sea, in which we recognise the well-
known property of the muriatic acid in the separation of
silver.

This writer says (if we may trust to the text being ac>-
curate) that in these places gold is inclosed in marble ; that
the miners burn or calcine the ore; that they break it with

* The art of assaying was certainly very imperfect at these periods : un-
der the emperors the standard of gold and silver was still judged of by the
colour assut ed by the coin in the fire, and by the tint given to the touch-
stone on which the metal was rubbed.

These methods, although practised by expert workmen, could yield but
very inaccurate results, which a variety of circumstances might influence ;
such as a complexity in the alloy, or a difFerent alloy, &c.

Archimedes would not have applied the laws of specific gravity to the
determination of the standard value of king Micro's crown, if he had
known a better method.

We know also that under the triumvirate of Mark Antony every street of
Rome erected a massive statue to Marcus Gratianus, who had discovered
and put in practice one of the processes of assaying mentioned above : this
denotes the infancy of an useful art, the first steps of which were strongly
encouraged as being intimately connected with public happiness.

f By employing the alkaline sulphurets, the solution of gold might have
been effected: it is the metallic sulphurets, however, which ought to be used
in this process.

* M. de Robilant, in his detail of the processes of the mint at Turin,
says that cementation is the mode of refining generally adopted at Venice,
Genoa, and at Florence, where they make gold seijuins almost entirely pure.

hammers,.

Observations on the Purity of Standard Gold. 137

hammers, afterwards pound it, bruise it, and wash it; and
finally, that the gold, when put into a close crucible, with
a little lead, salt, a little tin, and barley meal, was exposed
over the fire for rive days.

The money-coiners of Darius certainly employed this
method, or a similar one, when this enlightened king wished
<o give his subjects ihe noble and useful example of a mint
made with the purest gold, similar to that of fine silver,
which his satrap Ariander afterwards did.

To conclude: — It is not easy to form an intelligible idea
of the docimastic method, which Agatharchides has trans-
mitted to us. But if in the operation which he describes
there is no mention made of cementation, but of a true and
prolonged fusion, it remains to explain how we can re-
concile with the object in view, the employment of a close
crucible held over the fire, as he describes : far less can we
comprehend the use of the barley meal.

When we reflect, however, on the ingenious method de-
scribed by Heilot as being practised at Lyons, in order to
refine, purifv, and separate cupelled silver from the small
quantity of lead which adheres to it after the first refining,
we may perhaps comprehend what is meant *.

In Lyons they use crucibles thirteen inches high, and
five broad at their orifice. About three inches deep of
pounded charcoal is then put into the crucible and kept
down bv a lid, or rather a triangular piece of the crucible,
which is kept in its place. Oil this lid or false bottom
they put CO or 6 j pounds of long and thin ingots, in order
to be melted and purified. The wind furnace employed
for this purpose is 14 inches high, seven in diameter at the
grate, and nine at the top. The metal in melting was ob-
served to fall three inches from the edges of the crucible:
then, when it had acquired a sufficient degree of' heat, it was
seen to boil with the force and the agitation of' water ex-
posed to the heat of a strong fire ; and in this state it was
kept for seven or eight hours.

The elastic fluid, which in this case is extricated from
the charcoal at the bottom of the crucible, produces the
agitation above alluded to; and it forms, as it were, a kind

* It wou.ld be necessary, before deciding finally on the process detailed by
Agatharchides and that which is practised at Lyons, to repeat them, taking
the greatest care to apply the modern methods of chemical analysis, and
above all the pneumato-chemical apparatus: it would be necessary to de-
termine the nature of the gas, which passes through the melted siiver, and
ascert iin why the gas is formed under a certain pressure, and why it doet
out pass out through the pores of the crucible. The experiment of M. Fab-
broni does np£ seem to- mc to be conclusive.

of

13S Observations on the Purity of Standard Gold.

of bullous ingeniously placed at the botiom of the cru-
cible.

\Vc know that charcoal, when put into close vessels of
metal or glass, is not altered, although it becomes red.
Theory dictates this, and several experiments confirm it.
But the observation of the fact related by the judicious,
Heljpt also proves, that in this case the charcoal below the
melted silver is decomposed, and continually furnishes
elastic fluid j since this excellent chemist found that silver
kept over a similar lire, without charcoal being placed be-
low it, undulated at the surface, going from trie centre to
the edges, and vice versa ; but that in fact it does not bub-
ble wiih so much noise : from whence then does the elastic
fluid originate in this case?

Priestley, the founder of the modern pneumatic che-
mistry, demonstrates in the plainest manner, what has
been since confirmed by several other experiments, that
earthen vessels heated until they admit light to pa^s
through them, are filters, or rather sieves, which allow even
the external air to enter ; that caloric and light penetrate
by the bottom of the crucible, and with them air, at-
tracted chemically by the charcoal which is inside : its
oxygen coming in contact with the charcoal, which is in a
state of incandescence, inflames a portion of it, is combined
with itself and with the caloric, forming carbonic acid, an
elastic fluid, which, by t he uninterrupted action of the fire,
augments and acquires a sufficient elasticity to overcome
the pressure of a column of seven inches of liquid silver,
which is above, and passes through it agitating it violently.
The small residue of lead, which is united with and dif-
fused over the mass, being put by a continual agitation in
contact with the carbonic acid gas, and with the atmo-
sphere (the latter and perhaps the former are decomposed
by a greater affinity under certain circumstances), is oxi-
dated, and by the diminution of specific gravity is con-
strained to occupy the upper surface.

In fact, H el lot saw a kind of yellowish oil rise from the
inside of the silver which floated on the top of the crucible :
ibis oil was a pure oxide of lead melted and formed by the
contact of the atmospheric air, which is continually re-
newed. The refiners collect this melted oxide by absorbing
it with glass or with sour earth \ this earth being most
easily removed from off* the silver which it covers, and the
metal then remains limpid and pure.

On comparing this method with the process of Aaathar-
chjdcs, reported here so imperfectly, we may stibpy&e that

the

Observations on the Purity of Standard Gold. 13<>

the barley, or the barley meal, was used instead of charcoal,
in order to form what the Lyonnese call the soul of the
crucible, which was placed at the bottom of it, where it was
retained by a covering (from which probably comes the
expression of dosed crucible), on which i he 'gold in fusion
was placed by means of a little lead (in order to vitrify the
base metals which it might contain,) and some common
salt, sulphurct of antimony or of lead, in order that
they may lay hold of the fine silver and volatilize it with
the lead, or reduce it to scoriae. The elastic fluids, extri-
cated from the vegetable matter by the action of the fire,
form the office of bellows for incessantly agitating the
metal during several days, which makes all the impurities
swim above, and which ought to be skimmed off as the
Lyonnese do.

Properly speaking, a fire which lasts five days gives ra-
ther an idea of the cementation of the moderns, and ana-
logous to that which Pliny has communicated to us, than
a real fusion in close crucibles, — a circumstance which
would be directly contrary to the object in view. Thus, in
Hungary, in order the better to open all the interior parts
jof the gold to the muriatic acid reduced into vapour in the
cementation, they are accustomed to add lead to the mass,
which is afterwards reduced into small hollow drops, or, in
other words, into grains. It may be that the lead indi-
cated by Agatharchides has the same object: the tin may
have been taken by an equivoque for crude antimony, for
galenum, or for -the native sulphuret of lead: it is possible
likewise that the barley meal was merely intended to serve
for the equal distribution of the little salt, a stratum of
which must be placed on the gold, and perhaps assisted to
decompose it, as argil or sulphate of iron now does.

In order to obtain some light upon this curious subject,
there were put into a crucible covered by another crucible
turned upside down, thirty pennyweights of barlev-meal,
and an ounce of common salt: it was then made red-hot,
and kept 3r3 hours in this state. Tbe.e was put in, more
for the sake of curiosity than any thing else, a thin piece of
gold weighing 24 grains, and a piece of silver weighing 40
grains. The lower crucible was half full, and an opening
was left at the joining of the two crucibles to let out the
elastic vapour.

After this space of time, the apparatus being cooled was
opened, and there was found a small earthy residue slightly
saline and whitish, weighing eleven grains and a half. The
gold was above; it was increased one eighth'of a grain in

weight,

140 Observations on the Purity of Standard Gold,

weight, because it was evidently whitened by the fusion of
very minute particle* of silver detached from the small
fragment of silver, which was then found adhering imme-
diately over the gold, in the form of agglutinated dust :
this fragment of silver weighed six grains and one-eighth.
We afterwards boiled this gold (which was silvered only
6n its surface) for some time in pure nitric acid; when it
lost completely its silver colour; and when assayed it was
found to be 24 carats.

We proceeded afterwards to examine the small earth v
residue, in which we found, in saline particles, only a
few atoms of muriate of soda, and scarce a trace of muriate
of copper. The muriate of silver, which, on account of the
loss suffered by the piece of silver, ought to have formed a
weight of 45 grains and a half, was certainly evaporated with
the other elastic vapours. Eleven grains and a half only
of muriatic acid concurred in the formation of this muri-
ate: the thirteen pennyweights and a half of the same acid,
which besides contained the common salts employed in
this experiment, have therefore been dissipated (by not pay-
ing attention to the little copper) by a decomposition ef-
fected by means of the vegetable matter which was joined
with it : but what is difficult to account for, and which is
foreign to our object, is the evaporation of ten whole pen-
nyweights of soda, contained in the common salt, and
which ousrht to have remained fixed at the bottom of the
vessel: it had therefore become volatile, either by decom-
position, or by a new composition, and it had escaped by
the aperture in the apparatus.

It is not probable, therefore, that Philip made use of simi-
lar methods of refining, either by flux or by cementation,
because, we repeat, he would have reduced the gold to a state
of perfect purity, as Darius wished to do subsequently; or
he would not have limited himself to so small a portion of
alloy, or perhaps this alloy would not have been silver. And
if he employed gold in the state in which he found it, we
must be forced to admit that nature furnished it at 23 carats
and a half fine, or of the standard of (0*979*).

Many

* Reaumur says (Memoircs de 1' Acadrmiedcs Sciences 1718, p. 87.) that
The gold brought from the bed of the river Ceze is at the standard of IS
carats eight grains.

Gold of the Rhone . . . . . . 20 carats.

of the Rhine .. .. .. 2}i

of the Arritge . . . . . . i>'_'f

Reaumur also observes, that the standard varies in the same piece of na-
tive

Observations on the Vurity of Standard Gold, 1 4 1

Many persons will probably doubt that gold is found in
nature so near a state of perfect purity, although Strabo
intimates that perfectly pure gold was found in the Alps,
and Pliny is cited as asserting that no silver was ever found
in it. But without remaining in suspense with respect to
the assertions and opinions of others, I am enabled from
my own experiments to remove all uncertainty, having
ascertained that native gold is 24 carats (1000).

I had for some time the charge of the fine collection of
natural historv belonging to our sovereign, who was fond of
that science. His majesty possessed many specimens ot
mineralized gold and native gold, among which I remarked
two well formed crystals of gold, viz. one cubical, the other
prismatic with four faces, surmounted by a pyramid with
four faces also. It would be interesting to know what
substances united to the gold have determined these various
figures formed naturally in the bowels of the earth, and
which are totally different from those which are produced
in the laboratories of the chemist after melted gold is
cooled. The cube is very pale, the prism is higher co-
loured; but these two crystals, which I found by chance,
(when choosing among several natural grains,) are unique
in this depot ; so that it would be improper to subject
them to an examination which would alter their form.
An unshapen specimen, but at the same time a remark-
able one, from the Brazils, enriches this collection. The
weight of this piece is about fourteen pounds ; and I ex-
amined a bit of it by the cupel and by quartatidn, without
omitting also to examine its solution in the nitro-muriatic
acid, with the sulphate of iron, and with neutral salts with
a base of potash. I have been convinced by all these ope-
rations, that this was pure gold of 24 carats without any
alloy of inferior metal.

From all that I can learn, therefore, it appears that gold
is found in a native state in various degrees of purity, and
to prove this baa been the object of the present dissertation.

tive gold. M.Deluc informs us that the gold found at W'icklow in Ireland
was alloyed with a ninth part of its weight in silver.

M. Fabbroni is the iirst who has demonstrated that native gold is found
in a state of purity: thu is a most important observation; but it does not
teem to destroy the idea that native gold is a natural alloy of gold and silver:
a principle establislud by a great number of facts, and to which we as yet
know but one exception.

It would be interesting to ascertain whether lead is present in ancient coins
or medals : this would be the surest method of determining whether th^
ancients refined their gold, or employed it as nature presented it.

XXIII. An

[ 1« ]

XXIII. An Estimation of the Loss of Weight which take*
place in cooking Animal Food.

At is well known that, in whatever way the flesh of ani-
mals is prepared for food, a considerable diminution takes
place in its weight. We do not recollect, however, to have
seen any where a statement of the loss which meat sustains
in the various culinary processes, although it is pretly ob-
vious that a series of experiments on this subject would not
be without their use in domestic ceconomy.

We shall here give the result of a series of experiments
which were actually made on this subject in a public esta-
blishment, premising that, as they were not undertaken
from mere curiosity, but, on the contrary, to serve a pur-
pose of practical utility, absolute accuracy was not attended
to. Considering, however, the large quantities of provisions
which were actually examined, it is presumed that the re-
sults may be safely depended upon for any practical pur-
pose. It would no doubt have been desirable to have
known not only the whole diminution of weight, but also
the parts which were separated from the meat in the form
of aqueous vapour, jelly, fat, Sec, but the determination of
these did not fall within the scope of the inquiry.

ih. ozs.

28 pieces of beef weighing 2S0 0

Lost in boiling 73 14

Hence the weight lost by beef in boiling was in this case
about 26£lbs. in lOOlbs.

I's. ozs.

1 Q pieces of beef weighing 1 tjo 0

Lost in roasting 61 2

The weight lost by beef in. roasting appears to be 32 per
cent.

lbs. ozs.

Q pieces of beef weighing 90 O

Lost in baking 2/ O

Weight lost by beef in baking, 30 per cent.

llit. ozs.

<2J leos of mutton weighing 260 O

Lost in boiling, and by having the shank-') fi
bone taken off J

The shank-bones were estimated at four
ounces each ; therefore the loss by boiling was

The loss of weight in legs of mutton, in boiling, is 21£
percent.

35 shoulders

| 55 8

Oil the Arhor Diance. 143

35 shoulders of mutton weighing 350 O

Lost in roasting i0<) lO

The loss oF weight in shoulders of mutton, by roasting,
is about 3 Ji per cent.

lis. ozs.

J 6 loins of mutton weighing 141 0

Lost in roasting 49 14

Hence loins of mutton lose, by roasting, about 35] per
cent.

II"!. CZ.<!.

10 necks of mutton weighing 100 O

Lost in roast-ins 32 6

The loss of necks of mutton, by roasting, is about 32-J-
pcr cent.

We shall only draw two practical inferences from the
foregoing statement : — 1st. In respect of ceconomy, it is
more profitable lo boil meat than to roast it. 2dly, Whe-
ther we roast or boil meat, it loses, by being cooked, from
one- fifth to one-third of its whole weight.

XXIV. Letter from M. Vitams, Vrofessor of Chemistry at
Rouen, to M. Boi >llon Lagrange, oti the Amalgam of
Mercury and Siluer, called Arbor Diance *.

JL he process described by Bannie, and which is generally
adopted for obtaining the amalgam of mercury and silver,
known in chemistry by the name of arbor Diance, is not
the onlv one which is capable of exhibiting the beautiful
crystalline forms which characterize this curious produc-
tion. I attained the same object, by modifying the com-
mon method ; and this modification admits of our extract-
ing with facility the metallic vegetation from the liquor, and
preserving it, without any alteration, out of the vessel in
which it has been formed.

The operation is very simple. In the nitric solutions of
mercury and silver, both being well saturated and diluted
with the quantity of water prescribed by Baume, I suspend
a small knot of fine linen rag doubled up, and containing
five or six drachms of very pure mercury.

The metallic solutions soon penetrate to the mercury,
which is inclosed in the rag, and we soon see some beauti-
ful spiculae formed and grouped around the rag, adhering
to the nucleus of mercury, which serves as a kind of sup-
port to them.

• Annates tit Chimie, tome ixiii. p. 93.

These

144 Analysis of the Atropa belladonna.

These spicuhe progressively increase in size., and in s
short time exceed an inch in length.

When we perceive that the metallic vegetation makes
no more progress, the piece of rag vvrth the spiculse may
be withdrawn from the liquor, and by means of a silk
thread fastened to the cork of the bottle, the whole may
be suspended under a bell glass. The crystals, which are
tetrahedrons, may thus be kept as long as wanted.

I have in my own laboratory a crystallization of this
description, which has preserved all its original beauty for
these two years past.

It may be easily seen that, in the above process, the play
of attractions is a little different from the common method
as developed by M. Fourcroy in Systime des Connois sauces
chhniqnes.

The solidity of the metallic crystals obtained by my me-
thod, compared with the softness of the threads, the assem-
blage of which forms the common arbor Diana?, led me to
think that the proportions of mercury and silver are not
the same in both cases ; and I would have endeavoured to
have ascertained the difference, if M. Vauquelin, to whom I
communicated the circumstance, had not intimated his in-
tention of taking up the subject at full length, and publish-
ing his experiments in some future number of the Annahs
de Cfiimie.

The configuration of the above crystals also suggests
some interesting inquiries, which I may probably be able
to accomplish at a future time.

XXV. Analysis of the Atropa Belladonna. By M. Vau-
quelin *.

J. he experiments which I am about to detail were made
with a view to ascertain whether this plant, which is of
the same family with the tobacco plants, contained the
acrid principle which has been found in the latter, but
which, as will be shown in the sequel, it does not.

1. The expressed and filtered juice of the belladonna has
a dark brown colour, with a bitter and nauseous taste. It
is freely coagulableby heat, and by the aqueous infusion of
gall nuts.

2. The substance coagulated by fire in the juice of bella-
donna is of a yellowish gray, becomes black on desiccation,

* Annates de Chivrie, tome lxxii. p. 96.

and

Analysis of the Atropa Belladonna. 145

anil presents a smooth and polished fracture like that of
the resins. It burns with decrepitation, becomes soft, and
gives out vapours of the smell produced by horn when
subjected to the same operation.

3. The juice of belladonna, distilled until reduced to
the consistence of liquid extract, only furnished a water
which had a fetid j herbaceous taste, and by no means the
acerbity of that of tobacco. The only re-agent among all
those resorted to, which slightly disturbed it, was acetate
of lead.

4. The juice concentrated to the consistence of extract
having been treated by alcohol, a part was dissolved: the
Solution deposited upon cooling, crystals of nitrate of potash
and a little muriate of potash.

The alcohol separated from these crystals of nitrate of
potash^ and evaporated, left as a residue a brownish yellow
matter of an extremely bitter and nauseous taste, which, on
being taken up again by alcohol well dephlegrriated, left a
new quantity of insoluble matter, and also deposited some
crystals of the same salt*

The matter cleansed as much as possible by the above
process, rrom the greatest part of the saltpetre and from
the substance insoluble in alcohol, I evaporated the latter,
and submitted the residue to the following experiments :

1 . It is dissolved abundantly and speedily in water, and
it is even deliquescent in the air.

2. The solution is of a yellowish brown; it has a very
bitter and disagreeable taste.

3. It reddens in a very intetise manner turnsole paper.

4. It is precipitated in abundance by the alcoholic so-
lution of gall nuts, and is not so by the acetate of lead
when the latter is sufficiently diluted in water ; because, as
this matter contains a little muriate of potash, it would
precipitate the acetate of lead without this precaution.

5. This solution mixed with sulphuric acid diffused a
very sensible smell of acetic acid.

6*. The same solution is precipitated by the nitrate of
Silver in a true muriate of silver.

7. Caustic potash develops in the solution of this sub-
stance a fetid smell* very like that of an old ley which has
passed over linen and begins to turn putrid : ammoniacal
vapours also rise, which may be made perceptible by weak
nitric acid, presented at some distance from the mixture.

8. The addition of some drops of sulphate of iron gives
a much deeper colour to the solution.

9. The extract itself exposed to burning coals, bubbles
Vol. 36. No. 143. August 1810. K up,

14G Analysis of the Atropa Belladonna,

up, and exhales pungent acrid vapours, in which ammonia
cannot be distinguished.

We may conclude from the effects produced in the so-
lution oF the extract of belladonna by the various re-agents
above employed .- 1st, that it contains a free acid; 2d, an al-
kaline muriate; 3d, a small quantity of an ammoniacal salt.

The nature of the acid which exists in this substance
can be nothing but acetic acid, since the sulphuric acid
develops the smell of it, and the acetate of lead does not
form any precipitate in it, which would take place if it were
malic, tariarous, or oxalic acid. A part of this acid ought
to be combined with the potash, and it is without doubt
this combination which communicates to the extractive
mass the property of attracting humidity from the air.

But it is neither these salts nor these acids which give
poisonous qualities to the matter; these certainly reside in
the vegetable substance itself: what then is the order of
composition, which thus forms out of the same principles
both our food and our poison ? This is a difficulty which
chemistry has not yet overcome, and unfortunately it is
behind this barrier that secrets the most important to hu-
manity are retained.

For want of the means of ascertaining accurately the dif-
ferences which exist between vegetable compounds whose
properties are diametrically opposite, we shall have recourse
to their effects. ,

One of the means resorted to as the most proper for
guiding us as to the nature of the substance of belladonna
•soluble m alcohol, was its decompostion by means of heat. I
'introduced therefore two grammes and seven-tenths into a
gla*s retort, and administered the heat by degrees3 until the
water of solution was distilled: there passed over a yellow
ammoniacal liquid, afterwards a thick oil which had a very
singular disagreeable smell.

The examination of the liquid product enabled me to
•recognise a good deal of ammonia, partly free and partly
combined ; for the addition of some drops of caustic potash
rendered the ammoniacal smell much stronger, and the oil
was thick, black, and very acrid.

The charcoal remaining in the retort weighed one gram-
me, and had an alkaline and prussialed taste: when washed
in boiling water, it yielded a ley which when mixed with
•sulphate of iron furnished a quantity of prussian blue very
considerable with respect to trie small quantity of matter
xM*mloved. ' This charcoal after having been lixiviated and
dried still weighed -fa of a gramme.

The

Analysis of the Atropa Belladonna. 147

The above quantity of charcoal, independently of that
which was incrusted in the retort by the violence of the
fire, and which I could not detach, is more considerable
than any furnished by most of the other vegetable matters
which I have hitherto had occasion to distill ; for the 2*7
grammes of extract, in the state in which I took it, certainly
contained more than 0'7 of a gramme of water and of ni-
trate and acetate of potash.

It seems that it also contains a great quantity of azote
and of hydrogen, since it gave on distillation a great deal
of ammonia, prussic acid, and oil. But as this matter may
have contained a little nitrate, I supposed that a part at
least of the azote, forming the ammonia and the prussic
acid, had been produced by the nitric acid.

In order to clear up this doubt, I mixed six grammes of
gum arabic, believed not to contain any azote, with a
tenth part of saltpetre, and after submitting it to distilla-
tion I examined the products. The liquid which passed was
in part ammoniacal, and its smell became still stronger by
the addition of potash \ which proves that an acid was
formed at the' same time with the alkali.

The charcoal remaining in the retort, weighing two
grammes, and which was extremely phosphoric, contained
prussiate of potash, like that of my matter. But although
1 employed in this experiment three times more gum, and
probably more saltpetre, this mixture did not furnish such
a great quantity of ammonia or prussic acid as the nauseous
principle of the belladonna did.

Taking it for granted, therefore, that the saltpetre con-
tained in the two grammes of this principle had given rise
to prussic acid and to ammonia, we ought not to infer that
the vegetable matter in question lias not furnished some
itself. This is the more probable, as its solution is preci-

{)itated by the infusion of gall nuts. However this may
>e, the experiment proves that it is difficult to judge by
distillation, whether the organic matters which contain salt-
petre are of a vegetable or animal nature.

The results of this analysis, although still very imperfect,
are nevertheless sufficient to show that the article in ques-
tion contains a considerable quantity of charcoal, hvdrogen,
and azote, and but little oxygen, if we may judge by the
small quantity of carbonic acid which is formed during its
decomposition in the fire.

From what lias been said, may we be permitted to infer
that the narcotic effects of belladonna on the animal cecono-
my are owing to the superabundance of the radical com-

K 2 bustibles,

148 Analysis of the Atropa Belladonna,

bustibles, and particularly to that of the charcoal over that
of the oxygen in the principle of this plant soluble in alco-
hol ? — WiThout going the length of positively affirming it,
it is nevertheless certain that all the vegetable substances
which produce analogous effects are rich in charcoal, hy-
drogen, and azote, whereas substances that are highly oxy-
genized produce contrary effects.

It must also be admitted, that many vegetable products
equally abundant in these two principles do not possess the
tfame virtues ; but the azote, which is always found asso-
ciated with hydrogen and carbon in the narcQtic plants,
does not exist, at least in the same quantity, in those as in the
others.

Examination of that Part of the Belladonna which is insolu-
ble in Alcohol.

1. This substance dissolved in water communicates to
it the property of frothing when agitated.

2. Its solution is abundantly precipitated by the aqueous
infusion of galls.

3. By the nitrate of barytes into a matter which is partly
soluble in the nitric«acid.

4. By the muriate of lime into a precipitate entirely so-
luble in the nitric acid.

5. This solution reddens turnsole paper.

6. The nitrate of silver produces no effect on it.

7. When burnt in a crucible, it leaves an alkaline and
hepatic charcoal.

We may conclude from these effects, that this part of the
belladonna is composed of an anim<U matter, of sulphate of
potash, of acidulated oxalate with the same base, probably
some nitrate, and that it contains no muriate. We may also
conclude from these effects, that there are no earthy salts in
it, since the muriate of lime forms in it a precipitate, as
well as the nitrate of barytes.

I have ascertained by some experiments on a larger scale,
that the precipitates produced in the solution of the sub-
stance in question by the nitrate of barytes, were in the
first instance oxalate of lime, and in the second sulphate
of barytes.

The oxalate of lime had taken up with it a great quantity
of animal matter, which gave it a brown colour; which in-
dicates that this salt has a strong affinity with animal mat-
ters, and explains the reason of mural calculi, which, as we
all know, are composed of oxalate of lime, and are of a
much deeper colour than the other species of calculi.

1 After

Analysis of the Atropa Belladomia. ] 49

After having successively precipitated, as I have already
Baid, the sulphate of potash and the acidulated oxalate of
potash, I evaporated the liquor, which was always co-
loured, and which contained nitrate of potash and muriate
of lime, and I treated it with the nitric acid in order to
ascertain if it contained gum ; but not having obtained an
atom of saccho-lactic acid, I concluded that this substance
does not contain gum. It is merely formed of oxalic acid
and a yellow matter. This substance seems therefore to
be entirely of an animal nature.

From what has been said above, we find that the juice
of belladonna contains the following substances :

1. An animal substance, which is partly coagulated by
heat, and partly remains in solution in the juice, in conse-
quence of the free acetic acid which exists in it.

2. A substance soluble in alcohol, which has a bitter
and nauseous taste, which on being combined with tannin
becomes insoluble, and furnishes ammonia by its decom-
position in the fire.

3. Several salts with a base of potash, viz. a good deal
of nitrate, muriate, sulphate, acidulated oxalate, and acetate.

The refuse or husks of the belladonna, from which the
juice had been extracted, having been washed in warm
water, dried, and afterwards burnt, furnished ashes com-r
posed of a considerable quantity of lime, phosphate of lime,
jron, and silex. s

This lime announces that the plant contained oxalate of
lime, which had been decomposed by the fire. It is by no
means doubtful, that that part of the belladonna which is
soluble in alcohol is not the only substance which in
this plant produces a deleterious effect on the animal oeco-
nomy ; for it is the only one which has any taste; and the
well known effects of all the other substances which accom-
pany it have nothing in them resembling those of the plant
in question.

To put this assertion beyond all doubt, I administered
to a dog a certain quantity of this principle mixed up with
crumbs of bread.

First Experiment. About mid-day, I gave the animal a
gramme of extract invtlopcd in ten grammes of paste.

Symptoms. In about three quarters of an hour the
animal seemed inclined to sleep ; he held down his head,
and seemed unable to keep it up : he laid his head on the
ground several times, and slight convulsions agitated his
]egs : his jaws also moved as in the act of chewing. These

K 3 effect§

150 Analysis of the Airopa Belladonna.

effects lasted about three quarters of an hour, and the dog
then resumed his former appearance.

Second Experiment. At two o'clock I gave him two
grammes of extract with twelve of paste: the above sym-
ptoms re-appeared, but they were feebler and of shorter
duration. /

Third Experiment. At three o'clock, I made him swal-
low four grammes of the same extract, with about 30
grammes of paste.

A few minutes afterwards he was seized with a continual
but uncertain and difficult motion, chiefly in the abdominal
region : he uttered some plaintive moans.

At half past three he experienced great difficulty in mov-
ing, and frequently fell on his hind feet : his respiration
was much obstructed. He endeavoured several times to
force his wav through the wall, which indicated a kind of
delirium : he was now seized with trembling in all his
muscles.

At a quarter past four the animal lay down, and appeared
to be plunged in a profound sleep ; his pulsations were re-
peated faster than could be counted.

At half past four be vomited the paste which he had
taken, some time after which he rose up; but he still walked
with difficulty, sometimes falling on one side, and some-
times on his crupper. He held his head very low, hi*
eyelids fell, and he did not distinguish objects; at least he
continually ran against the walls, and the furniture of the
laboratory: his nose was no longer affected by the smell
of ammonia, and his ears seemed also to have lost their
functions, for the loudest noise made no impression on
him.

He had not lost his memory, however; for, upon placing
him in the same posture in which he was made to swallow
the paste, in order to give him some vinegar and water, he
became furious, as if all his powers were suddenlv renewed.
From this moment, the symptoms which he had exhibited
insensibly diminished, and about eight o'clock in the even-*
ing he recovered all his senses; but he was still much fa-
tigued. Next day he ate as usual.

Every one must recognise in the above symptoms the
effects of narcotics, and drunkenness carried to the highest
pitch, from which resulted a kind of delirium. It is pro-
bable that if the animal had not vomited the greater part of
the matter before it produced its effects, it would have died.

XXVI. Case

[ 151 ]

KXVI. Case of Hydrocele, improperly treated as Buptvre.
By John Taunton, Esq., Surgeon to the City and
Finsbury Dispensaries, and to the City Truss Society for
the Relief of the Ruptured Poor.

To Mr. Tilloch.

Sir, Jt is not the least of the evils which accompany a
state of distase among the poorer classes of this large me-
tropolis, that their complaints are frequently misunderstood,
and consequently treated in a manner which tends to in-
crease rather than to alleviate their sufferings. The super-
ficial and hasty view which is but too often taken, even by
regular medical practitioners, of the diseased victim of po-
verty on the one hand, and the allurements held out by
mercenary and ignorant pretenders to medical skill on the
other, are the causes of this additional affliction to the poor.

Those who officiate as medical officers to the numerous
public charities which do honour to this great city,, have
daily opportunities of witnessing the melancholy effec:s of
the errors thus committed. The following case of this
kind, which occurred lately uuder my own inspection, and
which bad nearly terminated iatally to the patient, is one
of the many illustrations of this observation which may
be adduced.

Thomas Erskine, set. 53, servant to Mr. Thomas Butcher,
of Charing Cross, a few years ago received a kick in the
scrotum, which occasioned a swelling, and which has con-
tinued ever since. At first it was attended with extreme
pain ; but this soon ceased, and the tumour assumed an in-
durated appearance. The poor man applied to tw.o regular
surgeons in his immediate neighbourhood, *yho informed
him that his complaint was a rupture, and recommended a
truss. Attracted by an alluring advertisement from some
truss-maktrs in Soho, the patient applied to them : these
gentlemen, after examining the patient, and affecting a
great deal of medical and anatomical knowledge, confirmed
the opinion of the surgeons, and applied a truss to the tu-
mour, for which they charged the exorbitant price of a
guinea. This happened three years ago, and the palient
has ever since worn the instrument thus applied, with more
or less inconvenience. A few weeks ago he was admitted
a patient at the City Dispensary, when on examining him
J found the ease to be a decided hydrocele. The operation
of tapping was immediately performed, and the patient in

K 4 a few

152 Royal Society.

a few days was restored to his former state of health,
Pilulae rhei cum terebinth, formed the only prescription
which 1 found necessary to administer.

I am, &c.

Grerille Street, Hatton-Garden, JOHN TAUNTON'

August 24, 1810. ' •

XXVII. Proceedings of Learned Societies,

ROYAL SOCIETY.

X he experiments detailed in Mr. Davy's paper respecting
the muriatic acid, of which we gave a brief report in our
last Number, are so highly interesting, that ho apology can
be necessary for again bringing the subject before our
readers, and endeavouring to present the results in a con-
cise yet perspicuous form. But before proceeding to this,
we must beg our readers to correct two typographical errors
in our last report. In page 71, line 20, for rt nine "modes,"
read nice modes; and in line 22, for " nine decUic^ions,"
read some deductions.

The conclusions drawn by Mr. Davy from the scries of
facts with which this valuable paper is enriched, will serve
to extend and enlighten the theory of chemistry to even a
greater extent than any of the brilliant discoveries formerly
made by this indefatigable philosopher. The following
are the conclusions to which we allude :• —

1st. The ox y muriatic acid is (as far as our knowledge
extends) a simple substance, 'which may be classed in the
same order of natural bodies as oxygen gas; being deter-
mined like oxygen to the pusitive surface in Voltaic com-
binations, and like oxygen, combining with inflammable
substances, producing heatand light.

2dly. That its combinations with inflammable bodies
are analogous to oxides and acids in their properties, and
powers of combination, but they ditTer' from t'nem in being
for the most part decomposable by water.

3dly. ''That' hydrogen is the basis of the muriatic acid,
and oxymuriatic acid its acidifying principle.

4thly. Thai the compounds or phosphorus, arsenic, tin,
Sec , with oxymuriatic acid, approach in their nature to
acids, and neutralize ammonia and other salifiable bases.

5thly That the combination of ammonia with phos-
phorus acidified by oxymuriatic acid is a peculiar com-
pound, having propertied like those of an earth, and is not
decomposable at an intenbe red heat*

6thly.

French National Institute. • 133

tfthly. That oxymuriatic acid has a stronger attraction,
for most inflammable bodies than oxygen; and that on
the hypothesis of the connexion of electrical powers with
chemical attractions, it must be highest in the scale of ne-
gative power ; and that the oxygen which has been sup-
Sosed to exist in oxymuriatic acid has always been expellee!
y it from water or oxides,

FRENCH NATIONAL INSTITUTE.

The readers of the Philosophical Magazine must have
seen from the accounts which have lately appeared ip our
pages, of the labours* of the French chemists, that those
gentleman had questioned the accuracy of the inferences
drawn by Mr. Davy from the numerous experiments he
had made, in the course of his electro-chemical researches,
respecting the nature o,f the alkalies and the earths; main-
taining that the metallic bodies obtained from these sub-
stances, in place of being simple, as asserted by Mr. Davy,
were compounds of the respective alkalies and earths with
hydrogen; or, in other words, that the new bodies were
hydrurets.. Of this opinion were Gay Lussac, Thenard, and
most of the French chemists. Berthollet among the rest
warmly contested the correctness of Mr. Davy's inferences,
and maintained the accuracy of the French conclusions.
They have now, however, changed their opinion, and done
justice to our countryman.

At a meeting of the French National Institute in the
end of June, Messrs. Gay Lussac and Thenard read a notice
containing the results of a great variety of experiments on
the new metals ; trom all of which they conclude, after a
most rigorous investigation, that professor Davy was per-
fectly correct in his inferences, and, with a degree of frank-
ness honourable to themselves, renounce their former
opinion that these new metals are hydrurets.

'We cannot but take notice here of an assertion made irv
the Report of the Labours of the Institute, (published in a
former volume of the Philosophical Magazine,) which sa-
vours of a blundering, but probably not intended, pla-
giarism. The Report states, that Messrs. Gay Lussac and
Thenard discovered the mode of metallizing ammonia by
potassium ; whereas these gentlemen themselves, who have
more than once uncandidly assumed Mr. Davy's facts,
acknowledge this to have been that gentleman's discovery,
in their paper on ammonia.

The result of the present contest, we cannot but hope,
will serve as an admonition to the editors of some of our

periodical

154 JV>7/' Method of constructing wooden Bridges,

periodical works, not to be hasty to commit themselves in
questions of science, on the authority of reports drawn up
by jealous rivals for national fame. We could name a
most respectable journal which has fallen into this blunder.
As to some more obscure writcrs/who have ventured to talk
about " the pretended discovery of the decomposition of
the alkalies," they will probably show a little more modesty
in their remarks in future.

XXVIII. Intelligence mid Miscellaneous Articles.

jVI. Wikbkking, director of roads and bridges to the
king of Bavaria, has discovered a method of constructing
wooden bridges, which in point of strength and solidity
promise a duration of several centuries. They are also re-
markable for the elegance of their form and the width of
the arches. A bridge has been constructed on the above
plan over the river Roth, five leagues from Passau, consist-
ing of a single arch two hundred feet wide: another
has been made for a large city, two hundred and eighty six
feet wide. These arches mav be so constructed as to ad-
mit of ships of war or merchant vessels passing through
them, an aperture being made in the centre, which can be
opened and shut at pleasure. Another advantage possessed
by these bridges is that of being speedily taken to pieces :
if it be necessary to stop the progress of an enemy, the
arch may be removed in one day, and th2 abutments in
another, without cutting the smallest piece of timber.

With respect to the advantages in point of ceconomy
resuliing from the adoption of M. Wiebeking's plan ; it has
been estimated that a stone bridge of similar dimensions to
a wooden one of a given size would cost two millions of
florins, whereas the latter would cost only 50,000 florins ;
and on the supposition that a wooden bridge will only last
100 years, it follows that, taking the interest on the prin-
cipal sum into the computation, there will result a sav-
ing of eleven millions six hundred and eighty thousand
florins.

The Pharmaceutical Society of Paris has announced the
following as prize questions for the present year :

1. Ascertain as far as possible, whether there exists in
vegetables an identical principle which chemists have de-
signated by the name of extractive? — Ought we to retain

the

New Optical Instrument. 155

the ancient classification adopted for pharmaceutical ex-
tracts, divided, according to Rouelle, into gummy, resi-
nous, gummo resinous, resino-gummy, and saponaceous
extracts ? — Can a more methodical and more exact classifi-
cation be established by means of chemical experiments
made on the principal substances in pharmacy furnished by
extracts ? — Indicate, according to the nature of their dif-
ferent constituent principles, the mode of preparation best
adapted for each, and the nature of the menstrua which
ought to be employed."

2. " What is the present state of pharmacy in France?
what rank does it hold in the healing art ? and what are the
ameliorations of which it is susceptible V*

The prize offered lor the best memoir on the first question
is a gold medal of the value of 200 francs. That offered for
the best paper on the second question is of the value of 100
francs. The memoirs to be transmitted to Paris on or be-
fore the 1st of October 1810.

The following account of a new optical instrument is
extracted from a recent French journal: " Jt is well known
that the art of perspective consists in representing on a plane
surface objects in the position in which the eye perceives
them. Descriptive geometry furnishes the means of doina
this; but the method which it teaches presupposes science,
and demands time. The painter, without having recourse
to geometry $ draws on a simple purview from habit and
practice in his art. However excellent his eve, and how-
ever skilful an artist mav be, he cannot flatter himself
with obtaining geometrical preeision. A new instrument
has therefore been invented, by means of which every
draftsman, without knowing the rides of perspective, may
design with ease and correctness all kinds of subjects on
every scale not exceeding 5 decimetres square. This inven-
tion belongs to M. Roggcro, of the Conservatory of Arts
and Manufactures.

tc Some very ingenious instruments have been already
contrived with this view, and amono; others that of Mr.
George Adams, who has been peculiarly distinguished.
But from the great number of joints of which the me-
chanism is composed, all of these instruments were more
or less liable to disadvantages, which M. Roggero's instru-
ment has overcome, lie has also united solTditv to preci-
sion in the transmission of the movements, besides having
furnished his instrument with ;n\ achromatic glass, by
means of which we may tracp'the perspective of object's
placed at a distance." On

1,56 Ichthyology.

On digging lately at Frescati in Italy, not far from the
ancient Tusculum,a quantity of amis, vases, human bones,
and a broken statue were found. The latter seemed to be
that of a Roman consul ; and a few days afterwards another
statue was found resembling that of a Roman matron.

M. Vincenzio has lately published at Rome two scien-
tific works: one entitled Lettere scicntifiche, and the other,
Spiegazione di due fascetti di gemma anticke. The same
author has also written a dissertation, to prove that the
colossal horses of the Ouirinal have been changed in
their places, and that they have been in fact badly placecj
originally.

ICHTHYOLOGY-,

Mr. Joseph Foster, fishmonger in Carlisle, has at pre-
sent in his possession a pilot fish, the only one we believe
that has appeared on these coasts. — The fish is of the order
of thoracici, which comprehends seventeen genera and up-
wards of two hundred and twenty species. It is found in
the Mediterranean and Atlantic, chiefly towards the equator;
The body is shaped somewhat like that of a mackarel ; the
head is long and smooth, and the snout advances some di-
stance beyond the mouth. It has two small fins ntarthe
head; another running along the back from the head to the
tail ; and one under the belly, of similar length. The co-
lour in general is brownish, changing into gold; and there
are several transverse black belts. Mariners observe, that
this fish frequently accompanies their vessels: and as they
see it generally towards the fore part of the ship, they ima-
gine it is employed in guiding and tracing out the course ;
whence it has received its name. Probably it is either
amusing itself, or pursuing its prey. It sometimes attends
the dog-fish and the shark ; and swims at the height of a
foot and a half from the snout of the latter ; imitates all
its movements, and seizes with address any part of the
spoil which the shark allows to escape. Though so small
as not to exceed six inches, it will keep pace with ships in
their swiftest course. — The one in Mr. Foster's possession
was caught a few days ago in the Sol way Frith.

A species of hemp, manufactured from the leaves of a
particular kind of palm, which abounds in Sierra L,eone
and its neighbourhood, has recently been sent to this
country; and being made into cord, subjected to experi-
ments calculated to ascertain its strength, as compared

with

Lectures. 157

\vith the same length and weight of common hempen cord,
the result was very satisfactory — it being found that hempen
cord broke with a weight of 43lbs. three-fifths, while the
African cord did not give way to less weight than 53lbs.
two-firths, making a difference in favour of the latter of
lOlbs. in 43lbs.

LECTURES.

Theatre of Anatomy {Blenheim- Street, Great Marlborough-

Street.

The Autumnal Course of Lectures on Anatomy, Physio-
logy, and Surgery, will be commenced on Monday the 1st
of October, at Two o'clock, by Mr. Brookes.

In these Lectures the Structure of the Human Body will
be demonstrated on recent subjects, and further illustrated
by Preparations, and the functions of the different organs
will be explained.

The Surgical operations are performed and every part of
Surgery so elucidated as may best tend to complete the
operating Surgeon. The art of Injecting, and of making
Anatomical Preparations, will be taught practically.

Gentlemen zealous in the pursuit of Zoology will meet
with uncommon opportunities of prosecuting their re-
searches in Comparative Anatomy.

Surgeons in the Army and Navy may be assisted in re-
newing their Anatomical Knowledge, and every possible
attention will be paid to their accommodation as well as
instruction.

Anatomical Converzationes will be held weekly, when
the different Subjects treated of will be discussed familiarlv,
and the Students' views forwarded. — To these none but
Pupils can be admitted.

Spacious Apartments, thoroughly ventilated, and replete
with every convenience, are opened all the Morning, for
the purposes of Dissecting and Injecting, where Mr. Brookes
attends to direct the Students, and demonstrate the various
parts as they appear on Dissection.

An extensive Museum, containing Preparations illustra-
tive of every part of the Human Body, and its Diseases,
appertains to this Theatre, to which Students will have oc-
casional admittance. — Gentlemen inclined to support this
School by contributing preternatural or morbid parts, sub-
jects in Natural History, £ec. (individually of little value to
the possessors) may have the pleasure of seeing them pre-
served, arranged, and registered, with the names of the
Donors. ...

Terms.

158 Lectures.

Terms. &. s.

For a Course of Lectures, including the Dissections, 5 5
"For a Perpetual Pupil to the Lectures and Dissections, 10 10
The Inconveniences usually attending; Anatomical In-
vestigations are counteracted by an antiseptic Process, the
result or' Experiments made by Mr. Brookes on Human
Subjects, at Paris, in the year 1782, the account or* which
was delivered to the Royal Society, and read on the 17th
of June 1784. This method has since been so far im-
proved, that the iiorid colour of the muscles is preserved,
and even heightened. Pupils may be accommodated in the
House. Gentlemen established in Practice, desirous of re-
newir.g their Anatomical Knowledge, may be accommodated
with an Apartment to Dissect in privately.

Theatre of Anatomy, Greville- Street , Hatton- Garden.

Mr. Taunton will commence his Autumnal Course of
Lectures on Anatomy, Physiology, Pathology and Surgery,
on Saturday, October 6th, at Eight o'clock in the Evening
precisely, to be continued every Tuesday, Thursday, and
Saturday, at the same hour. In this Course of Lectures it
is proposed to take a comprehensive view of the Structure
and CEconomy of the Living Body, and to consider the
causes, symptoms and treatment of surgical diseases, with
the mode of performing the different surgical operations.
An ample opportunity for professional improvement will
also be afforded by the attendance of the Pupils, if they are
so inclined, at the Finsbury and City Dispensaries, to which
Mr. Taunton is Surgeon. Further particulars may be had
on application to Mr. Taunton, at his house in Greville-

street.

St. Thomas's and Guy's Hospitals.

The Autumnal Courses of Lectures at these adjoining
Hospitals will begin the tirst of October, viz.

At St. Thomas's. Anatomy, and the Operations of Sur-
gery, by Mr. Cline and Mr. Cooper. — Principles and
Practice of Surgery, by Mr. Cooper.

At Guy's. Practice of Medicine, by Dr. Babington and
Dr. Curry. — Chemistry, by Dr. liabington, Dr. Marcet,
and Mr. Allen. — Experimental Philosophy, by Mr. Allen.
— Theory of Medicine, and Materia Medica, by Dr. Curry
and Dr. Cholmelev. — Midwifery, and Diseases of Women
and Children, by Dr. Haighton. — Physiology, or Laws of
ihe Animal Gvconomy, by Dr. Haighton. — Structure and
Dist'ascs/of the Teeth, by Mr. Fox.

,N. B. These several Lectures are so arranged, that no

two

List of Patents Jar new Inventions, lofj)

two of them interfere in the hours of attendance; and the
whole is calculated to forma complete Course or' Medical
and Chirurgical Instruction. Terms and other Particulars
may be learnt at the respective Hospitals.

Dr. Clarke's and Mr. Clarke's Lectures on Midwifery, and
the Diseases of Women and Children.

The Winter Course of these Lectures will commence on
Friday the 5th of October, at the house of Mr. Clarke,
No. 10, Upper John-Street, Golden-Square.

The Lectures are read every day from a Quarter past Ten
o'clock in the Morning till a Quarter past Eleven, for the
convenience of Students attending the Hospitals. The
Students will have Labours when properly qualified. For
particulars apply to Dr. Clarke, No. l, New Burlington-
Street; or, to Mr. Clarke, No. 10, Upper John-Street,
Golden-Square.

Mr. Stevenson,. of Great Russel-Street, Bloomsbury, who
as Pupil is intimately acquainted with the Practice of the
late Mr. Saunders, is preparing a practical Work on a fre-
quent Disease of the Lye, which we understand is nearly
ready for publication.

, LIST OF PATENTS FOR NEW INVENTIONS.

To Joseph Charles Dyer, of Boston, North America, now
residing in Westminster, a patent (in consequence of a
communication made to him by a certain foreigner residing
abroad) for certain machinery for cutting and heading of
nails and beads of all kinds and sizes, from strips or plates
made of iron, copper, or any other metal capable of being
rolled into plates. — July 26, 1810.

To Thomas Wade, of Nelson Place, Kent Road, in the
countv of Surry, gent., for Ins method, or process, of imitat-
ing lapis lazuli, porphyry, jasper, the various sorts or kinds
of marble, and all other stones usually wrought, carved,
sculptured, or polished ; also inlaid or Mosaic work to be
used for or in the formation or manufacture of chimney
pieces, slabs, funeral monuments, and for every other
purpose to which such stones and marbles are, or may be,
applied. — July L26

To Edgar Dobbs, of the Borough of Southwark, gentle-
man, for a variety of compositions for making a waier-
proof cement mortar and stucco, the same being also
applicable as durable colouring washes for buildings.—
August 2.

METEO-

166

By

Meteorology*

METROROtOGlCAL TABLE,

Mr. Carey, of the Strand,
For August 1810.

fhi

:rmorneter.

Days of

Month.

00 ""

c
a

2

o «

^2.

Height of

the Baroni.

Inches.

W a

Weather.

JuW 9f

60

62°

57°

29 50

10

Stormy

28

60

57

55

63

0

Stormy

29

61

64

56

•80

38

Cloudy

30

60

65

55

•68

36

Cloudy

3i

60

65

54

•80

28

Showery

August 1

59

66

56

•82

20

Showery

2

57

68

58

'95

42

Fair

3

59

66

57

•70

26

Showery

4

59

67

58

•54

33

Showery

5

60

70

56

•64

45

Showers with'

6

55

69

55

•64

46

Ditto [thunder

7

56

68

56

•62

30

Showery

8

58

66

57

•70

29

Showery

9

60

64

56

'95

32

Showery

10

61

67

57

•72

39

Fair

U

62

68

55

•57

41

Showery

12

60

69

58

•81

36

Showery

13

60

68

59

'71

44

Fair

14

60

69

55

•6g

33

Showery

15

59

63

54

•50

36

Fair

16

50

50

49

•60

0

Rain

17

51

61

49

•92

65

Fair

18

49

66

51

30-20

63

Fair

19

50

61

52

•21

0

Small rain

20

51

69

54

•28

60

Fair

21

56

69

58

•26

53

Fair

22

56

70

59

•03

50

Fair

23

58

74

64

•02

50

Fair

24

60

74

65

•01

61

Fair

26

61

76

64

29*99

59

Fair

26

60

71

68

30-01

43

Fair

N.B. The Barometer's height is taken atone o'clock,

ERRATUM.
Our readers are requested to correct the following typographical error m
the name of the author of the valuable paper on tunnels, ^iven «l page :>1y
of the present volume. For Lknnox read Lennok.

t V& ]

I

XXFX. A Sketch of a History of Pus* . By George
PearsOxN, M.D, F.R.S. Senior Physician of St. George's
, Hospital, o#c. &c.

was induced to write this historical sketch for three
purposes: namely ; 1st, To inform myself of the facts already-
published on the subject. 2d, To, perhaps, assist some others
with information. 3d, To manifest whether or not my own
investigation had produced any accession of knowledge.

The word pus, so very commonly used in our language,
is plainly the Greek word tfvo$ or ttmv abbreviated by the
Latins, with the change of writing in Roman characters*
It appears from the original writers that this term, denoted
any thick, white, opake, clammy, animal fluids such aa
the matter of abscesses, and of ulcers or sores; alsQ;tlj$
thick milk called colostrum secreted immediately after- par-
turition. I am of opinion that philological investigations-
are unsuitable in a writing1. of the same kind as tbis novtf
offered ; yet I think it may be useful or even necessary to
remark, that the etymological import of the word pus, is
that of putridity or corruption ; which, denotes a state of
broken down texture, not only of animal and vegetable
matters, but of any mineral substances whatever, such as
stones and metals*. Accordingly the word pus appears to:
have signified, among the Greeks, and Romans, an animal
fluid from matter in a state of broken down aggregation,
or of corruption; and such were the fluids above .named.;
Hippocrates distinctly describes the pus of abscesses and;
ulcers from its simple, obvious properties; viz. it is a thick,
white > inodorous > uniform, smooth fluid— when it is of a
good or " laudabte" kind. But according to its variations
from these properties, it was asserted to be of a. bad kind.;
It it> especially *>aid that good pus has not the least orlen*
sive smell. It was considered among the ancients to. be
of great moment to know the properties of this fluid, par-
ticularly fvr the purpose of determining whether or not the
sputum in pulmonary disorders was produced by an ulcer

* The acceptation of the term putridity, and of it.s derivatives according
to their confined meaning since the cultivation of chemistry as a distinct
science, and not according to the original extensive sense, is one of the
causes of the erroneous doctrines of fevers called putrid, which disgrace the
pages of some of our most eminent writers, 'I he modern meaning oiputre-
f action being that of the process of new compositions and decompositions in
animal or vegetable substances effected by clveinical attractions, and -cha^
racterized by fcetor, it is apparently incompatible for matter in a Jiving state
to exist" during such chemical agencies.

Vol. 36. No. 149. Sept. 1810. L or

162 A Sketch of a Mis lory of Pus,

or abscess. On that account mention is made of the trial*
with water and fire. Pus sinks, it is observed, in not only
mere water, but in salt water; while the secreted slimy sub-
stance of the bronchial membrane called mucus is frothy,
and floats on water : — the former substance is readily dif-
fusible through water, but the latter is not so. If pus be
contained in sputum, it emits a most offensive smell while
burning on an ignited coal. From the earliest writers it
appears that the judgement was regulated by observation
of the circumstances of the discharge of purulent matter,
as well as of its properties : that from suppurated tubercles
was distinguished from the abscesses called vomica, and em-
pyema by acute inflammation, such as of peripneumony
and pleurisy; but a third source from the lungs, now well
ascertained, viz. by secretion fron the bronchial membrane-
without any breach in its continuity or loss of its substance,
was made known in consequence of the observations pub-
lished about the same time by the learned De Haen of
Vienna, and by our most ingenious countrymen Mr. John
Hunter and Mr. Hewson. Previously to these pathologists,
Mr. Sharp in his Critical Essays, p. 142; and Mr. Gataker
mhh Essays, p. 97, as well as, I believe, other authors, had
asserted that puriform matter is producible without ulcer_
or loss of substance or breach, by inflammation, or merely
by irritation occasioned by extraneous bodies in gonorrhoea,
ophthalmia, &c. It was, however, generally considered as
doubtful, whether or not this matter was the same as that
of ulcers and abscesses. This indecision was founded, pro-
bably, on prejudice rather than on any actual observation
of differences of properties. The proof by dissection that
membranous surfaces, in their entire state, produce matter
of the same sort as that of sores and abscesses, was hitherto
the most important pathological fact brought to fight sub-
sequently to the Greek writers.

About 40 years ago, Simpson of St. Andrews, DeHaen,
Gaber, Pringle, Cullen, Fordyce, Hunter, Hewson with
his pupil Hendy*, were the prominent parties in the dis-
cussion of the point — the matter from which pus was im-
mediately derived. The first person who considered pus to be
the product of vessels becoming, or at least performing the
office of, glands, as far as I know, was Simpson. De Haen's
observations confirmed this opinion ; but the deposition of
an opake white matter from serum of blood on standing,
induced Gaber, Pringle and? Cullen to account for the pro-

* Tentamen Inaugurate de Secretionc glandulari. Edinburgh, 1774.

duction

A Sketch of a History of Pus. 1 63

duction of pus on the supposition of a similar deposition
from effused serum in abscesses and ulcers. Fordyce ap-
plied his chemical science, of which he was a master, on
this occasion : — he interpreted all the phenomena of sup-
puration by means of the principle of purulent fermentation,
which compounds pus from the supposed constituent or
elementary ingredients of any kind of animal matter, —
muscles, nerves, membranes, blood*, &c. This compo-
sition, however, was effected solely by the agency of vital
powers acting on such animal matters. Hewson sup-
ported by new arguments the doctrine of the production
of pus by secretion f. Hunter seems to have convinced
the medical public, by his ingenious observations and rea-
soning, that pus is a secreted fluid ; and, with the excep-
tion that inflammation is essential to its production, his
doctrine has been for the last 20 or 30 years generally ad-
mitted to be well established J. But the minds of the
thinking part of the medical faculty seem to have been still
left in an unsatisfied state with regard to the notion they
ought to entertain of the substance to be called pus. On
account of the few properties of it known, they probably,
and very reasonably, apprehended that different things
might be denoted by this term; or that things in reality
the same might be denoted by different terms, being sup-
posed to be different from one another. Accordingly, in
the course of the last 40 years, inquiries into the nature and
properties cf this fluid have been instituted, and been espe-

* Van Swieten seems to have entertained a somewhat like opinion :—
" Pus non fit in vasis sed extra vasa, in vulnere generatur ab effusis humori-
bus, calore corporis fotis et mutatis Si enim pus omne in vulnere haerens
linteis carptis mollissimis abstersum fuerit tenui liquido non pure post ho-
ram vulneris superficies undique madida apparebit; sed si per viginti
quatuor horas emplastro tectum fuerit vulnus, illo ablato pus apparebit.
Unde pus fit extra vasa ; sed materies, unde fit, per vasa adfertur."-— Com-
mentaria, torn. i. p. 2S0.

f Pus is found in cavities sometimes without ulceration; — globules are
perceived in it like those of milk — the quantity, the time of production, and
properties of pus are varied by the state of the constitution, particularly by
the passions — purulent matter is only the coagulable lymph altered, chiefly
by inflammation, in flowing through secretory vessels. See Experimental
Essays, by William Hewson, F.R.S. 1772.

\ I am unable to state precisely the date of Mr. Hunter's doctrine on this
subject ; but I learn from the Dissertation on Pus, by E. Home, esq. F.R.S.
1788, that he had delivered it, for many years preceding this publication,
in his lectures. Mr. Home states Mr. Hunter's conclusion? 5 " that the ves-
sels of the part take on the nature of a gland, and secrete a fluid which be-
comes pus."—" Pus is a secreted fluid, at least it is formed from a similar
structure of vessels as other secretory- organs from the blood." — "Changes ia
the constitution affect the state of the pus, which could not be the case if it
were made up of the solids and fluids of the part." For further proofs I re«
, fer to the ingenious Dissertation of the author.

L 2 cially

1 61 A Sketch of a History of Pus.

dally promoted by the honorary rewards offered by severaf
associated bodies. Hence some improvements have been
made. But physicians were still continually complaining
or the disadvantage in practice, from the distinguishing
properties of pus not being satisfactorily determined; above;
all, for the purpose of judging in pulmonary diseases whe-
ther or not the sputum was purulent. In the year 177®>
the late Mr. Charles Darwin received the gold medal
from the yE>culapian Society at Edinburgh, for his sup-
posed discoveries of the criteria by which pus and mucus
are distinguishable. It was asserted that, water being ad-j
ded to a dissolution of pus in sulphuric acid, a precipitation
talffes place, but such a dissolution of mucus affords on the*
addition of water merely suspended flakes ; — that pus is
diffusible through diluted sulphuric acid, but mucus is;
not; — that these effects are also observed with water, or salt
water. In 1787, Dr. Brugman, in his Inaugural Disserta-
tion on Pus, among a number of other experiments, which-
I do not think necessary to be noticed, relates that dry
volatile alkali (carbonate of ammonia) with an equal quan-
tity of pus becomes viscid, semi-transparent and white?
that caustic ammonia partially dissolves it, and the rest
yields a very viscid fluid, but on adding water the whole is
deposited in a viscid state; — that all neutral salts thicken
pus, and still more so the earthy salts, and most of all the
metallic salts ;-^-that alcohol condenses it by uniting to its
aqueous parts, but neither coagulates nor dissolves it. But
previously to these experiments, Mr. Hunter had observed,
that pus is " coagulated by sal ammoniac" (muriate of
ammonia), which he, and subsequently Mr. Home, depend
upon, as affording a criterion between pus and other animal
fluids. Grassmayer is quoted by several authors for the
fact that pus is precipitable in a gelatinous state by caustic,
alkaline lixivium, but if mucus be present it is suspended;
The mistake in the fact that pus was highly putrescible,
was perhaps first exposed by my fellow-student Dr. Hendy,
h iwas subsequently confirmed by Mr. Home. Several
foreign authors, as Plenciz, Murray, Schroeder, Salmuth,
^)ucsnay, either adopted subsequently, or coincided in, the
opinion that pus is a secreted fluid. Mr. Home's inge*
nious' Dissertation on Pus was published in 1788, audi
find ho accession of facts from that date up to the present
time. J J is wovk is valuable, not only for his own obser*
.vations, but for a just exposition of those of Mr. Hunter.
It is here attempted to be shown that f« pus is composed
of globules swimming in a transparent aqueous .fluid, yet

that

On different Systems of Tuning Musical Instruments. 1 65

that the globules are formed in the fluid after its secretion,
wh;le lying upon the sore or other inflamed surface, in
different times, according to the state of the constitution
and secreting part, the pus being secreted in a transparent
condition * ; — that inflammation is the absolute cause of
the formation of this fluid; that the globules in pus are not
soluble in cold water like those of blood, but are decom-
posed by boiling water, and the fluid in which they swim
is not coagulable by heat, but is by sal ammoniac, which
serum or the blood itself is not: the globules also are
smaller than those of chyle, but much larger than those of
pancreatic juice ; and they are of the same size, but les3
numerous than those of milk;-— that the distance from the
heart influences much the condition of the pus ; — that the
depravation of this fluid is in proportion to the flaky or
curdy particles seen floating in the fluid with the globules ;
and that the flaky parts are in the greatest proportion where
the inflammation has been least, or the process on other
accounts most defective.

In this historical account of the fluid under inquiry, if I
have omitted to state the observations of any other authors,
that must be imputed to my unacquaintance with them.
I also purposely do not notice various pathological facts;
such as the effects of pus of variolous eruptions, siphylitic,
and other contagious diseases. As it appears from the
confession of physicians that the nature and distinguish-
ing properties of pus have not been satisfactorily ascer-
tained, I engaged in an inquiry into the properties of this
substance ; some of the results of which I shall offer to the
public.
«■ ) . -, , ■ ■ '

XXX. Eeinarks on the Rev. C.J. Smyth's Letter on Systems
of Tuning -Musical Instruments. Vol. xxxv. p. 448.

After bestowing cUie praise on Mr. A. F. C. Kallmann's
improvement of the theory of musical composition,
Mr. S. makes objections to Kirnberger's temperament,
which Mr. K. had recommended on page 9 of his " New
Theory;" and concludes with several assertions of little

M papcrvn rhpertorared Matter, (see Phil. Ma*, vol xxxv.
p, 12 — 20,) I erroneously assigned the discovery of the globularity of pus to
vu ! Icune. It is but justice in me to declare that this Gentleman no
whe.v chums the discovery : on. the contrary, I have since found that he re-
feio it to Mr. Hunter. I rake for gr*nMdcHtft&onta observation of this fact
;»Jre;:Jy enjo^. . !y to Mi\ Hunter's, hut 1 find no authority

.for the jeiact period of the discovery by either p arty,

L 3 weight,

166 Remarks on Systems of Tuning.

weight, because (and I consider his " palatable dishes*')
they are mere matters of taste. And it is curious that he
should presume " organ-tuners will continue to tune in the
same way as their ancestors did before them, till arguments
are produced to prove the superiority of Kirnberger's tem-
perament" to theirs; for a person but slightly acquainted
with the subject might from this suppose there are no bet-
ter unequal temperaments. However, there are others
which, for my own part, I do decidedly prefer. Un-
doubtedly Kirnberger's system is one of the worst ; and in
the ancient system (as M. de Bethizy observes, Exposition,
p. 130, 1764), the sounds in some of the scales are so
altered that they are insupportable to a delicate ear. The
equal temperament has been preferred by Couperin, Mar-
purg, Rameau, Cavallo, professor Chladni, and many other
eminent philosophers and musicians: it is certainly the
best for piano fortes ; but for the organ perhaps a good
unequal temperament is better, on account of the loudness
of the beats.

As one of your musical readers, I am obliged to Mr. S.
for undergoing "the drudgery of calculation" on our ac-
count : he would still further merit our thanks by sending
to your valuable Magazine tables of the numbers of vibra-
tions, the monochord-lengths, and the beats in fifteen se-
conds, belonging to the other unequal temperaments that
have been proposed ; and I think he ought to send a table
for the common system, as the chief end of his communi-
cation seems to be, to compare it with Kirnberger's, and to
show its superiority *.

As to the generality of tuners (and many of them are
very conceited men), I believe they know but little or no-
thing of harmonics. They learn one method by ear only,
and remember it as they would a tune, without knowing a
rule on which either is founded. That the ear and the
memory alone are sufficient, after proper exercise, I am
well convinced ; for I can tune my harp with the same ac-
curacy diatonically and without sounding two strings at a
time, as it can be tuned in the usual way by consonances ;
and I have a pupil, only twelve years old, whose ear and
remembrance of sounds are so accurate, that she can, while
in a different room from the instrument, name any num-

• It would be an improvement of the first column of these tables, to foN
low the German tabiature, described in art. 34 of Dr. Callcott's Musical
Grammar, 2d edit. 1809. Mr. S. in some future communication, would
much oblige me by stating precisely what he means by the terra Wolf'm
tuning.

ber

On Tuning an Equal Temperament. 167

ber of notes that can be struck with one hand in any part
of the piano forte which she has been a little while accus-
tomed to play on,

I know one tuner who, after studying ratios a little,
thinks with Eximeno : — " Qua! sciocchezza non e qucsta,
supporre la musica fondata in certe ragioni, che bisogna
guastare per ridurre la musica ad esecuzione ? Almeno
msegnasse la matematica a far quesio guastamento ; ma
dopo un grand' apparato di ragioni matematiche, ciascun
le guasta per la pratica a modo suo. I Francesi hanno
fatto peril temperamento del cembalo difusissimi calcoli ;
ma tutti egualmente capricciosi che inutili, poiche in fine
Vistinto senza riguardo a* numeri c' insegna ad accordar
gli strumenti, come c' insegna a metter insieme le lettere
per formar le parole, &c." p. 71.

August 11,1810. M.*

XXXI. An Examination of the Instructions given in an
anonymous Pamphlet published in 1 809, for Tuning an
Equal Temperament of the Musical Scale, By a Cor-

BESPONDENT#

To Mr. Tilloch.

Sir, ± he table by your correspondent the Rev. Mr. Smyth,
at page 452 of your last volume, has enabled me to make a
comparison of the method of tuning laid down in a recent
pamphlet, sold by Becket and Co. ; and perhaps you will
oblige me in laying the same before your readers, with the
necessary plate and extracts from the pamphlet alluded to;
which, after some well directed sarcasms, explains the nature
of the musical scale and the necessity of temperament, by
a professed extract from Earl Stanhope's pamphlet, that
was reprinted in your 25th volume. It then proceeds to
extract Mr. Emerson's opinion, in favour of the Equal Tem-
perament; founded solely, on there being wo fifth in it,
which is tempered more than -^ part of a note; while the
more important circumstances are overlooked, that there
are in it 12 major thirds, each of which is more than -^
part of a note too sharp, and 12 minor sixths as much too
flat; also 12 major sixths almost -fa part of a note too
sharp, and 12 minor thirds as much too flat.

In page 21 of the pamphlet, I find an expression, di-

* Can any of your readers favour me with any particulars respecting the
manufacture of tuning-forks, and the standard by which they are tuned?

L 4 rectly

#$8 On Tuning an Equal Temperament.

•rectly contrary to what your correspondent Mr. Smv
.says,' at page 450, as to l lie temperament now in use upon
the organ, viz. Organs are " universally tuned according to
the equal temperament-:" and the author continues^ " the
trials which I have myself made of the equal and unequal
temperaments, amongst the latter of which was that re-
commended by Earl Stanhope, have induced me to adopt
the equal temperament as the best for practice."

" The method of tuning a piano-forte, &c. according to
the equal temperament, is explained by the following in-
structions, and further elucidated by the annexed tuning
table*, to which the reader is desired,, as he proceeds, to
refer."

" Observe, that the capital letter? in the tuning table, in-
dicate the notes when tuned ; the small letters, the notes
to be tuned from them ; aim1 the crosses the notes already
tuned, with which the tuning notes are to be tried in
chords, as will be shown in the instructions ; and that these
crosses stand for the natural -notes, except when otherwise

marked." . , , I fft

1. " By means or a tuning fork, tune the C next above
the middle C, and from the former, tune the middle c a
perfect octave.

2. "From middte'C tune g, next above it, a little flatter
than a perfect fifth : and in order to ascertain whether it is
too flat or not flat enough, try it in a chord with the two
C's already tuned. If it make a tolerably good fifth, with

, the C below, and at the same time a tolerably good fourth,
with the C above, it is ivell tuned:'

Here, sir, I have to remark, that the little which the
fifth Cg is to be flattened, supposing the tenor- clifFc
of the usual concert pitch, or to make 240 c6mplete vi-
brations in cue second of time,1 is just such, according
' to Mr. Smyth's table, that it may beat" 12 times in
one quarter of a minute, or 15 seconds, a space of
time always to be understood when a number of beats
are mentioned, in what follows: and that the pre-
tended trial in the latter part of this precept, is inap-
plicable ciiid ridiculous, since every 'complement of a
tempered concord, to the octave, is alike tempered
with itself, wiale'ver that degree of temperament may
. and consequently whether well or ill tuned, for the
purpose of an ei/ual temperament, is almost as remote
from this test, as would be the hour or minute of the
(lay, on which such fifth was tuned..

# See Plate V.

3. " From

On Timing an Equal Temperament. I69

3. " From G tunc g below it, a perfect octave, and try
it in a chord with the C between them.''

4. " From the last tuned G tune d a little flatter than a
perfect fifth, and try it in a chord, with the G above it al-
ready timed, until you have Gd a good fifth and dG a good
fourth. "

This fifth G d must beat 9 times, and the fourth d G
1^ times*, and the pretended trial is nugatory and
absurd, for its professed purpose.

5. " From D, tune a, a little flatter than a perfect fifth,
and try it in a chord, with C above it, until you have Da
a good fifth, and aC a good third/'

The fifth D a must beat 13 times : and the first trial
or check of any use which occurs, is the minor third
aC, beating 326 times, but which no organist in Eng-
land would, I think, call " a good third."

6. " From A, tune a below it, a perfect octave, and try
it in a chord with D between them."

7. i\ From the last tuned A, tune e a flat fifth, and try
it with C and G, until you have three good thirds, AC,
Ce,eG.

Now since the minor third AC beats 163, and the
thirds Ce and eG, 142 and ,244 respectively, such
must be tried a long time, so that all idea of perfect
chords is forgot, before any musician would pronounce
them " good thirds."

8. " From E, tune b a flat fifth, and try it with G, until
you have two good thirds EG and Gb."

This -flr'th Eh must beat 15 times, and the thirds
above mentioned will beat 244, and 21.4, and conse-
quently are noi " good thirds."

9. ff From £>, tune b below it a perfect octave, and try
it with D and G."

lirre b.D beats 183, and GB beats 214; on which
I forbear to comment.

10. <•" From the last tuned B tune f* a flat fifth, and try
it with'D and b until you have Df* a good third, and f*B
a good fourth,"

Now Bf# beats 11 times, and 160 and 22 are the
other beatings.

11. "From F*, tune f* below it a perfect octave, and
try it with A and D."

* Because the minor consonance (the 4th) is the uj\ ermost son Dr. Sm a*s
Jlannomcs, 2d edit. p. 93. Here

1 70 On Timing an Equal Temperament.

Here f*A beats 137, and DF* beats 160 times.

12. " From the last F* tune c* a flat fifth, and try it
with A and F* until you have Ac* a good third, and c* F*
a good fourth."

The fifth F*c* beats 8|, and the major third Ac*
120; of course the fourth C* F* beats 17, the same
with its complemental fitth above it.

13. "From C* tune g* a fiat fifth, and try it with E
and B until you have Eg* a good third, and g*B another
good third."

The fifth C*g* beats 12 times; also Eg* beats 180,
and g*B beats 308.

14. " From G* tune g* below it, a perfect octave, and
try it with E and B."

g*B beats 154, the half of the above, and EG* 180
as above, and the repetition, and the whole of this
step is unnecessary,

<c As you now proceed by tuning the fifths downwards,
the lower "note is to be sharpened, which is the same thing
in effect as flattening the upper note, when tuning up-
wards."

15. "From C above middle C, tune f rather sharper
than a perfect fifth, and try it with A and C, until you
have f A a good third, and Cf a good fourth."

Here the fifth f C beats 16 times, and so does the
fourth Cf, and the trial of it is useless and fallacious,
for proving whether f C is sharpened the proper quan-
tity for an equal temperament of the scale. But f A
beats 190, and this furnishes a check of some use.

16. " From F tune a* a sharp fifth, and try it with D,
until vou have a*D a good third, without sensibly injuring
the fifth."

The fifth a*F beats 10§ times, and the third a*D
beats 127 times.

17. "From A* tune a* above it, a perfect octave, and
try it with D and F."

Here A*D beats 127 times as above, and a*F 10J
times, the same as the last, which shows this to be a
useless step.

18. From the last tuned A* tune d* a sharp fifth, and
try it with G and A* (below) until you have A*d* a good
fourth, and d*G a good third."

Here

Analysis of several Varieties of Salt. 171

Here the fifth d*A* beats 14 times, and the fourth
A*d* the same, and the third d*G beats 169 times.

From the above comparisons of Mr. Smyth's table, with
the rules in this pamphlet, it will I think appear plain, that
the writer of them had no proper conception of the nature
of an equal temperament, and that it is extremely unlikely
that he had ever heard or calculated such a temperament,
decidedly as he speaks of his trials of it: and I fear, sir,
that this is no uncommon case, in the present rage for
writing principles of music, principles of tuning, theories
of harmonics, instructions for tuning, 8cc. &.c. by persons
who ought first to employ themselves, in studying the very
.elements of the science of harmonics.

Among the recommendatory criticisms for different Re-
views, of the pamphlet before me, one for the Phil, Mag.
has been forgotten, which I suggest should have run thus :

A careful examination of the instructions contained in this pamphlet,
for tuning an equal temperament, convinces us, that the assumed name
Musicus Ignoramus of its author, is no misnomer ; and that the wit dis-
played therein, vastly exceeds its science, or its usefulness.

I beg pardon for obtruding so long a letter on your at-
tention, and am, sir,
August 6, i8io. Yours, &c. &c. &c.

XXXTf. An Analysis of several Varieties of British and
Foreign Salt, (Muriate of Soda,) with a vieiv to ex-
plain their Fitness for different oeconomical Purposes. By
William Henry, M.D. F.R.S. Vice-Pres. of the Li-
terary and Philosophical Society, and Physician to the
Infirmary, at Manchester.

[Concluded from p. 119.]

Sect. III. Account of the Methods of analysing ike se-
veral Varieties of Muriate of Soda.

JL he method of analysis which I adopted, in examining
the several varieties of muriate of soda, was as follows.

When the salt was in a state of solution, a measured
quantity was evaporated to dryness in a sand heat, which
was carefully regulated, to avoid the decomposition of the
muriate of magnesia, if any of that salt were present in the
solution *.

• Muriate of magne'sia, according to Dr. Marcet, begins to part with its
acid at a temperature a few degrees above that of boiling water. This fact
explains the observation of Mr. Kirwan, that too great a heat, employed in
the desiccation of muriate of magnesia, decreases considerably its solubility
in alcohol. (Kirwan on Mineral Waters, p. 215.)

Each

1 72 Analysis of several Varieties of

Each specimen of salt was reduced to a fine powder, and
was dried, in the temperature oi 180°. of Fahrenheit, during
the space of two hours. This was clone in order th
different ex peri men: s might be made on precisely equal
quantities of salt.

I. To separata the earthy Muriates.

(A.) On 1000 grains of the dried and pulverized salt,
(except in the case or' the foreign salts, when only 500
grains were used,) four ounce measures of alcohol were
poured, of a specific gravity, varying from 815 to 820, and
at nearly a boiling temperature. To insure the access of
the fluid to every part of the salt, they were ground toge-
ther for some time in a mortar, and then transferred into a
glass matrass, where they were digested for some hours,
and frequently agitated. The alcohol was next separated
by filtration, and the undissolved part was washed, as it
jay oti the filter, with four ounce measures of fresh alcohol.

(B.) The united washings were evaporated to dryness*,
and to the dry mass a small portion of fresh alcohol was
added, to separate the earthy muriates from a little common
salt, which had been dissolved along with them. This so-
lution might, however, still contain a minute portion of
muriate or soda. It was therefore again evaporated, redis-
solved in hot water, and mixed with a solution of carbonate
of soda. By boiling for some -minutes., the whole of the
earths were precipitated, and, after being well washed, were
re-dissolvcd in muriatic acid. This solution, being eva-
porated to dryness, gave the weight of the earthy muriates,
wh re h had bee hex trae ted b y al coh ol f .

(B.a.) The dry mass thus obtained might consist either
of muriate of magnesia, of muriate of lime, or of both.
An aliquot part, therefore, was dissolved, separately, for
the purpose of assaying it by the usual tests. Sometimes,
as in the case of the earthy muriates procured from sea salt,
muriate of magnesia alone was indie/, .- d, and any further
process was rendered unnecessary. Muriate of lime was

* In this and all similar cases, the heat was very cautiously regulated to-
wards the close of the piob

•j* By the analysis of arrificia: mixtures of pure muriate of soda with the
earthy muriates in known quantities, I afterwards found- that the frill
amount of the earthy muriates was not ascertained in this w.iy of .proceeding.
The deficiency of the latter salts was ahout one sixth; but as the error must
necessarily have bee:* the samy in all, it does not affect the comparison of
different varieties of salt, as to their proportion of this ingredient. If the
numbers in the 5th c : . table (indicating: the total earthy mu-

riates) be increased in the proportion of six to five, we shall then obtain the
*rue quantities in each variet

m

i

British and Foreign Salt. 173

hi ho instance found uncombined ; but in the majority of
cases (as in the earthy muriates obtained from Cheshire)
salt was mixed with muriate of magnesia.

(B.b.) TV the solution of two earthy muriates was
added fully'saturaied carbonate of ammonia, which has thd
property of throwing down lime in combination with car-
bonic acid, but has no effect on the muriate of magnesia at
ordinary temperatures. The 'solution of the latter salt, along
with that of the excess of carbonate of ammonia, was
therefore separated by filtration ; and to the filtered liquor a
solution of phosphate of soda was addedj according to the
formula of Dr. Wollaston*.

(B.c.) By direct experiments I had learned that 10O
grains of muriate of magnesia, when thus decomposed by
carbonate of ammonia, conjoined with phosphate of soda,
give 151 grains of an insoluble ammoniaco-magnesian
phosphate dried at about 90° of Fahrenheit. Hence it wag
easy, from the weight of the precipitate, to calculate how
much of the former salt was contained in the mixture
of muriate of lime and muriate of magnesia. Thus, if 20
grains of a mixture of the two muriates yielded l.W of
ammoniaco-magnesian phosphate, it is obvious that the
mixture must have consisted of equal weights of muriate
of lime and muriate of magnesia.

(B. d.) T«he estimation of the proportion of muriate of
rime, in a mixture of this salt with muriate of magnesia,
vvas sometimes performed in a diti'e rent way. To a cold
solution of a known weight of the two salts, super-oxalate
of potash was added ; and the precipitate was collected,
washed, and dried at about {CO'5 Fahrenheit. Of this pre-
cipitate f had previously found that 1 16 grains are formed
by the decomposition of 100 grains of dry muriate of lime.
From the qiiantit/of oxalate of lime it was easy, therefore,
to infer that of the muriate, from whose decomposition it
resulted ; and this subtracted from the weight of the two
salts^ gave the weight of the muriate of magnesia.

II. To separate a fid estimate the earthy Sulphates.

(C.) The portion of salt which had resisted the action
of alcohol, was dissolved by long boiling in sixteen ounce
measures of distilled water, and the solution was filtered.
On the filter a small quantity of undissolved matter ge-
nerally remained, which was washed with hot water, till it

• * See Dr. Marcet's analysis of the Brighton Chalybeate, published in th$
last edition of Saunders, on Mineral. Waters.

ceased

174 Analysis of several Varieties of

ceased to have any action. The weight of the insoluble
portion was then ascertained*

(C. a.) By this operation were, dissolved, not only the
muriate of soda, but all the other salts, insoluble in alco-
hol, which might he mingled with it. To the solution,
carbonate of soda was added; and the liquid, which in
most cases gave, on this addition, an abundant precipitate,
was boiled briskly for several minutes, in order that none
of the earthy carbonates, which were separated, might re-
main dissolved by an excess of carbonic acid.

(C. b.) The precipitated earths were allowed to subside,
and were well edulcorated with boiling water, the washing
being added to the liquor first decanted from the precipitate.
To these united liquids (after the addition of more mu-
riatic acid than was required for saturation) muriate of
barytes was added, till it ceased to occasion any further
precipitate. The sulphate of barytes was then washed suf-
ficiently; dried; ignited; and its amount ascertained.

To the earthy carbonates, an excess of sulphuric acid was
added in a platina dish, and the mixture was triturated, till
all effervescence ceased. It was then evaporated to dryness,
calcined in a low red heat, and the weight of the earthy
sulphates was ascertained.

(D.a.) The dry sulphates were washed with a small
quantity of lukewarm water. In several instances, the loss
of weight, thus sustained, was extremely trifling, nothing
being dissolved but a very minute portion of sulphate of
lime, of which earthy salt, solely, the residue was presumed
to be composed.

(D. b.) But in other cases, a considerable loss of weight
ensued ; and in these, to the watery solution was added a
mixture of equal parts of saturated solutions of carbonate
of ammonia, and phosphate of soda. A precipitate more
or less copious was produced, which was collected, dried at
90° Fahrenheit, and weighed.

(D. c.) By direct experiments I had determined, that 90
grains of this precipitate result from the decomposition of
100 grains of sulphate of magnesia, of such a degree of
dryness, as to lose 44 grains out of 100, by exposure to a
low red heat. Hence 100 grains of ammoniaco-magnesian
phosphate indicate 111 grains of crystallized, on 62*2 of
desiccated, sulphate of magnesia*. From the weight of

the

* The assumption that crystallized sulphate of magnesia contains only 44

Fer cent, of water, though it was correctly true with the specimen on which
operated, is below the average, which, I find from several experiments, is

about

British and Foreign Salt. 1 ?3

the ammoniaco-magnesian phosphate, it is easy, therefore*
to infer the proportion of sulphate of magnesia in any mix-
ture of the two earthy sulphates.

(D.d.) It was possible, however, that in addition to the
sulphates of lime and of magnesia, the quantity of which
had been determined by the foregoing process, the speci-
men of salt under examination might contain also an alka-
line sulphate. To decide this point, it was necessary to
compare the amount of the acid, deducible from the weight
of the sulphate of barytes (C. b.), with that which ought
to exist in the sulphate of lime and sulphate of magnesia
actually found by experiment. But to make this com-
parison, some collateral experiments were previously ne-
cessary.

(D. e.) By these experiments, I found that sulphate of
lime prepared by double decomposition, then calcined in a
low red heat, and afterwards dissolved in a large quantity
of boiling distilled water, yields, when precipitated by a
barytic salt, in the proportion of 175*9 grains of sulphate
of barytes from 100 of the calcareous sulphate*. The
same quantity of ignited sulphate of lime (=128 grains
dried at 160° Fahrenheit), precipitated by super-oxalate of
potash, gives 102*3 of oxalate of lime; or, precipitated by
sub -carbonate of potash at a boiling heat, 74*3 grains of
carbonate of limef. One hundred grains of crystallized
sulphate of magnesia ( = 56 desiccated) afford, when preci-
pitated by muriate of barytes, 111 or 112 of the barytic
sulphate.

(E.) By a comparison of the above proportions with
those obtained in the analysis of any specimen of com-
mon salt, we may learn whether it contain other sulphates
beside those with earthy bases. For example, if the pre-
cipitate (D.) consist of carbonate of lime only, and bear to

about one half the weight of the salt. Mr. Kirwan states the water of cry-
stallization to be 53*6 in 100 grains; but this, I believe, a little exceeds the
truth. ^

* This result corresponds, within a fraction of a grain, with one obtained
in a somewhat different way by Dr. Marcet, and ve-y nearly with an ex-
periment of my friend Mr. James Thomson, who found the barytic sul-
phate, precipitated from 100 grains of sulphate of lime by nitrate of barytes,
to weigh 173 grains.

f On reversing this experiment, I found that 100 grains of carbonate of
lime, saturated with sulphuric acid, and calcined in a low red reat, afford
135 of sulphate of lime. A similar experiment of Mr. Thomson gave 134*6
grains. Dr. Marcet also informs me, that from 9355 grains of pure marble
he obtained 1 25*95 grains of sulphate of lime, proportions which exactly
coincide with those of Mr. Thomson.

the

176 Analysis of several Varieties of

the sulphate of barytes (C. b.) the proportion of 74 to l1$f
or very nearly so, we may infer, that no other sulphate id
present but that of lime. The same conclusion will tal-
low, if, after having decomposed one half of the watery
solution (C.) by muriate of barytes, and another half by
oxalate of potash, we find that the sulphate of barytes bears
to the oxalate of lime, the proportion of 175*9 to 102*5.
Now these proportions were, as nearly as could be ex-
pected, obtained in ibe analysis of North wich salt; from
tvhence we mav conclude, that the only sulphate which it
contains is gypsum, or the sulphate of lime

It must be remembered, however, that the calcareous
sulphate, contained in any variety of common salt, cannot
be in a state of complete desiccation, but. would lose 22
parts out of 100, bv exposure to a red heat*. It becomes
necessary, therefore, either to increase, in the proportion
of 5 to 4, our estimate of the sulphate of lime obtained
by the foregoing rule, or, more simply, to assume that 10O
grains of sulphate of barytes indicate 73 grains of sulphate
of lime, dried at 3 60° Fahrenheit, =57 ignited.

(F.) When sulphate of lime and sulphate of magnesia
were both ascertained, and other sulphates also might pos-
sibly be present, as in the varieties of salt from sea water,
the calculation became a little more complicated. In this
case, after determining the quantity of both sulphates, (by
the processes D. &c.) I estimated how much sulphate of
barvtes they ought respectively to afford ; and then com-
pared the estimated quantity, with that which was actually
obtained. The earthy carbonates, for.example, precipitated
from 1000 grains of Lymington salt, which had previously
been digested with alcohol, were converted into 31 grains
of calcined sulphates, consisting of 19 grains of dry sul-
phate of magnesia, and 12 grains of dry sulphate of lime.
Now from the magnesian sulphate 38 grains of sulphate of
barytes should result, and from the sulphate of lime, 21 grains,
the sum of which is 59. But the quantity actually obtained
was 59*8. There is only, therefore, an excess of 0*8 grain of
the actual above the estimated quantity, a difference much
too trivial to be admitted as an indication of any sulphate
with an alkaline base; and arising, probably, from un-
avoidable errors in the experiment.

* This I find to be the loss sustained by 100 grains of artificial selenite,
dried at 160°, 'and then ignited. The same quantity of crystallized native
selenite, 1 learn from Dr JNIarcet, loses 20-7 grains, by being calcined in a
strong red heat.

(F.a.)

British and Foreign Salt. 177

(F. a.) If in any mixture of salts, free from the earthy
muriates, we are certain that no other sulphates exist be-
side those of lime and magnesia, their estimation becomes
extremely simple. Decompose two equal quantities of the
salt in question, the one by muriate of barytes, the other
by oxalate of potash. From the weight of the latter pre-
cipitate, we may calculate the quantity of sulphate of lime.
Suppose, for example, the oxalate of lime (as was actually
the case with the precipitate from 1000 grains of Lyming-
ton salt) to weigh twelve grains; these denote 15 of sul-
phate of lime, dried at 160° Fahrenheit, which quantity, if
decomposed, would give 20^ of sulphate of barytes. The
latter number (20-£), subtracted from the weight of sulphate
of barytes actually obtained (say 60), gives 3ox grains for
the sulphate of barytes resulting from the decomposition
of sulphate of magnesia. The quantity of the latter salt,
it will be found therefore by applying the rule already given
(D. e.), must be 35 grains.

(F. b.) The same object may be accomplished by decom-
posing two equal quantities, the one by oxalate of potash,
the other by the compound solution (D. c). From the
weights of the precipitates, it is easy to calculate from how
much of the calcareous and magnesian sulphates they have
resulted.

(G.) When the salt left by alcohol was known to con-
tain muriate of soda and sulphate of magnesia, but no sul-
phate of lime, the presence of alkaline sulphates was in-
vestigated in the following manner. The salt was dissolved
in water, and the solution was divided into two equal por-
tions. To the one muriate of barytes was added, and to
the other, the compound precipitant of carbonate of am-
monia, and phosphate of soda. If the sulphate of barytes,
thus produced, bore to the ammoniaco-magnesian phos-
phate the proportion of 112 to 90, it was concluded that
no other sulphate had been decomposed, but that with base
of magnesia.

(H.) At one time I expected to have ascertained the
quantity of sulphate of soda, in an artificial mixture of that
salt with sulphate of magnesia and muriate of soda, by the
following formula. To d solution of the three salts, heated
to a boiling temperature, I added sub-carbonate pf am-r
monia, which decomposes the sulphate of magnesia only.
I had then a solution containing muriate and sulphate of
soda, with sulphate of ammonia; and some carbonate of
ammonia. This solution was evaporated to dryness^ and

Vol. 36. No. 149. Sept. 1810. JVI * the

1 78 Analysis of several Varieties of

the mass was sufficiently heated to expel the ammoniacal
salts. I found, however, that at this temperature the sul-
phate of ammonia acted upon the muriate of soda, and
produced an additional and not inconsiderable quantity of
sulphate of soda.

Having determined, by the foregoing processes, the
quantity and kind of (he earthy muriates, the amount of
the insoluble matter, and the proportion of sulphates, the
weights of all these different impurities were added together ;
and the sum being deducted from the weight of the sale
submitted to experiment, the remainder was assumed as
the amount of the pure muriate of soda in the specimen
under examination *.

Though I purposely refrain from giving the details of the
several analyses, which were made according to the fore-
going plan, from the conviction that they would be both
tedious and unnecessary, yet there are a few circumstances
which it may be proper to mention more fully than car*
be done in the form of a table.

1. The brine which I examined was from Northwich,
and was sent to me in the state in which it was taken fro»ri
the spring f. At the temperature of 56° Fahrenheit, it had
the specific gravity of 1205. It was perfectly limpid, but
lost a little of its transparency when raised to a boiling
heat, in consequence of the deposition of a very minute
quantity of carbonate of lime and oxi^e of iron. It was
immediately precipitated by muriate of barytes, oxalate of
ammonia, and alkaline solutions, both mild and caustic.
Eight ounce measures, evaporated to dryness in a sand heat,
gave 1230 grains of salt, which, for the sake of distinction,
I term entire salt. It proved, on analysis, to contain i«
one thousand parts J ;

* I have deemed it unnecessary to state, in the table, the quantities of
acid and base in the several varieties of muriate of soda. They may readily
be estimated from the proportion, deduced by Dr. Marcet, of 46 acid, and
54 soda, in 100 of the pure muriate. In this determination he assumes, that
100 parts of luna cornea, after being melted and heated to redness, consist
of 1905 parts of acid, to 80-95 oxide of silver. This statement agrees very
nearly with the recent one of Gay Lussac, who makes 100 parts of silver
to combine with 7-60 oxygen, and this oxide to neutralize 25'71 parts of
real muriatic acid.

4- I have lately been informed that this brine had been pumped out of a
rock-salt mine, into which, from the impossibility of obtaining the salt in a
solid form, it was allowed to flow. Hence it was fully saturated with muriate
of soda.

| The specific gravity and proportion of earthy sulphates in Cheshire brine
appears to differ considerably in the brine of different springs. See Hol-
land's Cheshire Report, p. 45, &c.

Carbonate

British and Foreign Salt. 179

Carbonate of lime and oxide of iron ........ 2

Muriate of lime, and muriate of magnesia, inl

nearly equal proportions J

Sulphate of lime 19

Muriate of soda 974

1000.

2. The mother liquor, or brine that remains after sepa-
rating all the common salt, which it is thought worth while
to extract, had the specific gravity of 1208. The dry salt
contained,

Muriate of magnesia . . * 35

lime . . 32

Sulphate of lime 6

Muriate of soda .............. 927

1000.

3. The clearings of the brine, which are raked out of the
pan when the salt first begins to granulate, contained in
1000 parts,

Muriate of soda 800

Carbonate of lime 41

Sulphate of lime 159

1000.

4. Of the substance called by the workmen pan-scale,
two specimens were analysed, the one containing a large
proportion of muriate of soda, the other very little. The
first variety consisted of

Muriate of soda 950

Carbonate of lime 10

Sulphate of lime 40

1000.
The second variety was composed of

Muriate of soda 100

Carbonate of lime 110

Sulphate of lime 790

1000.

Circumstances, however, are constantly occurring to
vary the proportion of ingredients, both in the clearings
and in the pan- scale. If, for example, the brine be short
of the point of saturation with common salt, it acts, when
admitted into the pan, upon the muriate of soda which the
pan-scale contains, and we obtain the second variety. But

M2 if

1 80 Analysis of several Variet les of Salt.

if the brine be fully charged with salt, it effects no solution
of the muriate of soda, carried down along with the gyp-
sum; and then the first species of pan-scale results.

5. The salt oil, or mother liquor from sea water, a spe-
cimen of which I received from Dr. Thomson^ had the
specific gravity of 1277- It was abundantly precipitated
by muriate of barytes ; by pure ammonia, but not by the
carbonate ; and was not changed by oxalate of potash,
either immediately or after an interval of some hours. One
thousand parts of the dry salt consisted of

Muriate of magnesia 874

Sulphate of magnesia 70

Muriate of soda 56

1000.

6. The salt Irine, or liquor which drains from the Scotch
salt, had the specific gravity of only 1 188. It was affected
by the same tests as the salt oil, but less remarkably. The
dry residue contained

Muriate of magnesia 205

Sulphate of magnesia 135

Muriate of soda 1 . 660

1000.

7. The mother liquor, or lit tern pan Lymington, pre-
sented, on analysis, an unaccountable variation from the
similar fluid sent from Scotland, and gave a much larger
proportion of sulphate of magnesia. A considerable quan-
tity of this salt had, moreover, crystallized in the bottle
which contained the liquid. Its specific gravity was 1280.
One thousand parts of the dry salt contained of

Muriate of magnesia 640

Sulphate of magnesia 260

Muriate of soda 1 00

1000

8. The pan-scale from Lymington contained

Muriate of magnesia 29

Desiccated sulphate of magnesia 18

Carbonates of lime and magnesia* ... 127

Sulphate of lime 216

Muriate of soda 610

1000.

* The proportion of these carbonates I was by an accident prevented
from determining.

From

Analysis of the Scammonies from Aleppo and Smyrna. 1 81

From the very near approximation of the proportions be-
tween the sulphate of barytes and ammoniaco-magnesian
phosphate, obtained in the analysis of all these products of
sea water, to those which result from the decomposition of
two equal quantities of sulphate of magnesia, it may be
inferred that they contain no sulphate of soda*., For ex-
ample, to decide whether the Scotch salt contains an alka-
line sulphate, or not, I dissolved 1500 grains in a pint of
boiling water, and evaporated till fourteen drachm measures
only remained, the common salt being removed as soon as
it was formed. The residuary liquid was divided into two
equal portions, one of which gave \S\ grains of sulphate
of barytes, and the other, 14 grains of ammoniaco-mag-
nesian phosphate. The proportion between these numbers
is so nearly that which has been already assigned, (viz. 112
to 90,) that we may safely infer the total absence of sul-
phate of soda. This salt, indeed, is considered as incom-
patible with muriate of magnesia; but after digesting, for
two or three days, 100 grains of the former, with 20 of the
latter, evaporating to dryness, and washing the residuum
with repeated affusions of alcohol, I found that two grains
of the muriate of magnesia had escaped decomposition.

Manchester, June 19, 1809.

XXXIIP. Analysis of the Scammonies from Aleppo and
Smyrna; to which are subjoined some Observations on the
red Colour given to Turnsole by the Resins. By Messrs,
Bouillon Lagrange and VoGELf.

J_ he two species of scammony in question are procured
from the root of a plant which grows in Syria. It seems
that il is by an incision made in the root that the juice is
extracted ; each root yields about two drachms. only. The
juice thus extracted is dried in the sun, and then exposed
for sale : at least it is in this way that the finest and purest
scammony is obtained. Frequently, however, the inhabitants
of Syria and Natolia, in order to procure a greater quantity
of the sap, extract it by expression, not only from the
root, but from the stalks and leaves: occasionally also they
adulterate the scammony by mixing the juice procured from

* l employed more attention in investigating the presence of sulphate of
soda in the products of sea water ; because this salt is stated to be one of its
ingredients by the Bishop of Llandaff, (Chemistry, vol. ii. p. 62,) and by
other chemical writers.

f Annates dc CUimie, tome lxxii. p. 69.

M3 it

1 82 Analysis of ilte Scammoniesfrom

it with that of some other milky and acrid plants, and
sometimes they increase its weight by the addition of char-
coal or other foreign substances. In order to ascertain
that scammony does not contain any of these heterogeneous
matters, we ou^ht to break the pieces of the juice, and pick
such as are brilliant within, rejecting those which appear
too black, burnt, or sandy.

The scammony of Aleppo is light, of an ash gray, bril-
liant and transparent in its fracture. That of Smyrna is
very compact, heavy, and of a deeper colour : it is also more
difficult to reduce into powder than that of Aleppo.

Examination of the Scammony of Aleppo. — When the
scammony is pure, it melts entirely on a plate of heated
iron, and gives out nauseous vapours : when pounded in
water, the liquor is of a milky whiteness.

Boiling water makes it run into a mass. The liquor be-
comes yellow^ has a bitter taste, and is neither alkaline nor
acid, which proves that this substance is not adulterated
with ashes, as some authors assert.

Alcohol at 40 degrees forms a slight precipitate in this
aqueous liquor, and with the acetate of lead we obtain yel-
lowish flakes soluble in the nitric acid.

The alcoholic tincture of scammony is of a brownish yel-
low colour. This liquor reddens turnsole tincture : there
remains, after the evaporation, a resin of a yellowish whit&
and transparent.

This resin is entirely dissolved in the nitric acid, which
is coloured yellow. The addition of water slightly dis-
turbs the liquor.

This substance is equally soluble in a solution of pure
potash, even cold, and the liquor acquires a yellow colour:
if this solution be made with the help of heat, the colour
is brown. Water even in great quantity does not precipi-
tate resin. Even when saturated by the muriatic acid, it
does not separate the resin. This triple compound of
resin, acid, and potash, ought to excite the attention of prac-
titioners : it would perhaps be possible in this way to find
a solvent for resins which water does not afTect.

That part of scammony which is insoluble in alcohol,
when dried, acquired a gray colour.

When treated with boiling water, it coloured it yellow,
and alcohol precipitated it in white flakes.

In order to determine the proportion of the constituent
principles of the scammony of Aleppo, we took 100 parts
of this substance, which we dissolved in alcohol : the liquor
was coloured yellow. There remained, after the treatment

by

Aleppo and Smyrna. 183

by alcohol, a matter of a gray colour, which, when dried,
weighed 0*26.

The alcoholic solution was evaporated to a syrupy con-
sistence. Cold water precipitated from it a resin forming
a homogeneous mass : the supernatant liquor was trans-
parent and colourless. Evaporated to dryness, we obtained
a brown matter soluble in water and in alcohol, forming a
precipitate by the acetate of lead. This substance seems
to be what is called the extractive matter : its weight was
found to be 0'2 after having been dried.

The resinous mass separated and dried had a yellow co-
lour, and weighed 0*60.

We afterwards treated the 0*26 of matter which was in-
soluble in alcohol, with boiling water. There remained
after the evaporation a gluey matter, weighing 0*3, having
all the characters of gum. The rest was merely the refuse
of vegetable matter and a little silex.

The distillation of the scammony of Aleppo presented
nothing remarkable. It gave as products, a very acid
brown liquor and a light blackish oil. The charcoal re-
sulting from the operation was black, brilliant, and compact;
it contained carbonate of potash, carbonate of lime, alu-
mine, silex, and a little iron.

Examination of t fie Scammony of Smyrna.- — The fusion
of the Smyrna scammony is less complete than that of
Aleppo : instead of going into a mass with boiling water,
it became knotty, and the water was dyed yellow. It is
neither acid nor alkaline : the acetate of lead precipitates
yellowish flakes from it.

100 parts of this scammony taken up by boiling alcohol,
although less charged with resin, gave a deeper-coloured
tincture than that which was made with Aleppo scammony.
We obtained from the evaporation of the alcohol a brownish
transparent resin, the weight of which was 0*28. We
found 066 of insoluble matter in the alcohol. This re-
sidue treated with boiling water coloured it yellow : it had a
putrid sweetish taste, and alcohol precipitated from it flakes
soluble in water. The liquor evaporated left a thick gluey
matter like mucilage, soluble in weak nitric acid when
warm ; precipitating, on cooling, a white pulverulent matter
which presented all the characters of mucous acid.

Iivthis experiment, the water had only taken up 0*8 of
the matter which was insoluble in the alcohol. The rest
was submitted, with the help of heat, to the action of the
nitric acid, which dissolves it with effervescence. Am-

M4 monia

18-4 Analysis of the Scammon'tes from

rnonia added to this nitric solution formed a precipitate so-
luble in potash. The potash and the oxalate of ammonia
also occasioned a precipitation. This residue is composed
therefore of alumine and carbonate of lime, besides the re-
fuse of vegetable matter, and that substance which is inso-
luble in water and in alcohol, a substance which seems to
be oxygenated extract.

This substance incinerated left a whitish powder, solu-
ble in a great measure, and with effervescence, in the mu-
riatic acid. This solution contains alumine, lime, and a
little iron. The portion not soluble in the muriatic acid,
when treated by potash, gave a siliceous precipitate on the
addition of an acid.

The water which had served to precipitate the resin, left,
after the evaporation, a brown substance, weighing 0*5, of
a bitter taste, attracting humidity from the atmosphere,
soluble in alcohol, and abundantly precipitated from the
aqueous solution by the acetate of lead. This substance
presented all the properties of the extractive principle.

It results therefore from this analysis : 1st. That 100
parts of Aleppo scammony are thus constituted :

Resin 60

Gum 3

Extractive principle 2

Vegetable and earthy matter, &c 35

100.
£?. That Smyrna scammony contains :

Resin . . . ; 29

Gum . . . I 8

Extractive principle * . . . . 5

Vegetable and earthy matter 58

100.

As the resin obtained from both kinds of scammony is
much the same, excepting that the Aleppo resin is yellow,
transparent and friable, whereas that of Smyrna is more
highly coloured and more difficult to pulverise, we thought it
would be useful to ascertain if there was any difference in
their medicinal properties. Several physicians have since
made experiments with both kinds on individuals of similar
habits, and have observed no difference in point of purga-
tive properties.

We may conclude therefore, from what precedes, that
scammony is a true gum resin mixed with a little extractive

matter.

Aleppo and Smyrna. 185

matter. Tt contains indeed much less gum than the other
gum resins, but enough, however, to form a milky liquid
with water.

The action of the alcoholic tincture of scammony on
turnsole, naturally led us to ascertain whether the property
of reddening this blue colour was owing to an acid. Our
experiments not having enabled us to acquire a direct
proof, we tried some resins in a comparative manner, which
we submitted to the following experiments.

]. Sandarach. This resin is converted into a knotty or
grumous mass on being boiled with water. The filtered
liquor remains- clear: when properly evaporated, it slightly
reddens turnsole tincture: the taste is bitter : it does not
change the infusion of violets, is not precipitated by alco-
hol or by the acetate of lead ; which proves that it contains
neither gum nor extractive principle. It is therefore a pure
resin.

The resin which had bCen treated with boiling water,
was dissolved in alcohol. This liquor reddens turnsole
tincture strongly, and has no action upon syrup of violets.

We also digested sandarach reduced into powder in al-
cohol, adding to the liquor, when warmed and filtered,
boiling water, which precipitated the resin from it. The
filtered liquor was turbid upon cooling. It had the strong
smell of sandarach resin : its taste was bitter; and its action
on turnsole tincture was so weak, that we could not pre-
sume the existence of a free acid.

2. Mastich. This substance presents nearly the same
phaenomena with the above : the resin however runs into a
mass in boiling water like turpentine. The water has a
bitter taste, and has no action either upon turnsole or upon
violet syrup. The resin, on the contrary, reddens turnsole
tincture strongly.

3. Olibanum forms in hot water a thick magma, which
is separated with difficulty from the liquor, even by filtra-
tion. This water has a blackish brown colour, is not pre-
cipitated by the acetate of lead, and does not change the
colour of turnsole, but alcohol precipitates it in abundance;
which proves that this substance is composed of gum and
resin.

The alcoholic tincture reddens turnsole tincture strongly.

If we carefully heat in a sand bath the resins which have
most action on the colour of turnsole, no acid is sublimed.

When treated with lime according to Scheele's process,
no calcareous benzoates are formed.

4. Ammoniacal gum resin, myrrh, gum elemi, gal-

banum,

1 80 On prime and ultimate Ratios.

banum, tacamahaca, resin of common jalap, Venice tur-
pentine, oil of turpentine, and several other resinous and
gummo-resinous substances, gave the same results with
those obtained from the scammonies, sandarach, and o!i-
banum. From these facts we may infer that it is still dif-
ficult to resolve this question : Is it to the presence of an
acid in the resins, that we ought to ascribe the reddening of
turnsole ?

► If the acids alone had the property of reddening the blue
vegetable colours, we should not hesitate in recognising the
existence of this property in the resins, although experiments
have not yet proved it. As to the infusion of violets, over
which the resins have no action, this property is found in
the sublimated benzoic acid, which strongly reddens turn-
sole tincture, and which does not change the colour of vio-
'lets. Has this acid, notwithstanding its solubility in water,
any analogv to the resins ? We shall abstain from deciding
on this subject, although we are induced to believe that this
substance is a compound of a vegetable acid, and a small
quantity of resin, which perhaps gives it the concrete state:
lastly, as all the vegetable acids are soluble in water, it is
still difficult to ascribe to the presence of an acid, the pro-
perty which resins have of reddening turnsole. It seems
probable therefore, until some new experiments prove the
contrary, that we may regard it as being one of the cha-
racters of the resins to redden the blue colour of turnsole.

XXXIV. On prime and ultimate Ratios; with their Appli-
cation to the first Principles of the Jluxionary Calculus.
By Mr. Mark at.

JLyatio denotes the relation which two quantities bear to
each other.

The two quantities must be of the same kind, otherwise
no comparison can be made between them.

The measure of a ratio is obtained by considering what
part, or parts, one te. in of the ratio is of the other. Thus,

let a and b denote the tertns of a ratio, or let y express

any ratio; then, its measure is had by considering what
part, or parts, a is of b, '

Let us denote a by 6, and b by 2, then, -|= f, or 3 is the
measure of the ratio £ .

If a=2 and Z/=6, then, ■§.=-] ; or -J- is the measure of
the ratio of, |-; and so on for other quantities.

The

On prime and ultimate Ratios. 187

The part b of the ratio is called the antecedent) and a is
its consequent.

The antecedent may be equal to the .consequent, and
then the ratio is called a ratio of equality ; though it would
be more proper to say, the terms of the ratio are equal :—
when the terms of a ratio are equal, its measure is always
equal to unity.

If the terms of a ratio vary, the measure of the ratio
may have any magnitude whatever ; and if one term re-
main constant while the olher\ varies, the measure of the
ratio will vary with the varying term.

Let — represent any ratio, and let a remain constant,

while b is variable; it is obvious that if b decrease, the
measure of the ratio will increase ; and, when b is become
indefinitely small, the measure of the ratio is then indefi-
nitely near to a; and when b entirely vanishes, the mea-
sure of the ratio is exactly equal to a.

On the contrary, when b increases, the measure of the
ratio decreases. Again, let b remain constant while a is
variable: then, as a increases the measure of the ratio in-
creases, but it decreases as a decreases, and when a entirely

vanishes the measure of the ratio is equal to —.

As another example, suppose we have the ratio >

where x is variable and a constant ; the measure of this
ratio may vary through all possible degrees of magnitude, as
in the preceding example.

1. Let x continually increase ; then, the measure of the

ratio — - will decrease; and when x is indefinitely great, it

will become nearly a constant ratio, or a ratio of equality ;
that is, the terms of the ratio will be nearly equal : be-
cause the addition of a to a quantity x which is indefi-
nitely great, will alter the measure of the ratio only in an
indefinitely small degree: hence it continually verges to a
ratio of equality as a limit.

2. Let x decrease ; then, the measure of the ratio r

x
will increase; and when x is indefinitely small, the measure
or the ratio is indefinitely .near to a:' when x vanishes, the
ratio is equal to a, exactly.

From the above illustrations it is exceedingly obvious,
that a ratio in which the terms continually vary, or where
one is variable and the other constant, or where part of one
term is constant, as in this latter example, — it is obvious,

I sa\>

188 On prime and ultimate Ratios.

T say, that the measures of such ratios never can attain the
limits which we have assigned to them : they may, how-
ever, continually approximate towards them ; and when the
measures of the ratios differ from those limits by less than
any assignable difference, they may be said to be equal.

This being allowed, it is evident that in making use of
those ratios, after having supposed that they have attained
to such ultimate states, or limits, we continually approxi-
mate towards true results ; and when the results thus ob-
tained, differ from the true results by a quantity indefinitely
small, they may be said to be indefinitely near the truth,
and in practice the indefinitely small error may be neg-
lected, as being of no sensible magnitude.

This is all that Newton meant in his first lemma in the
Principia, where he says that Ci quantities, and the ratios
of quantities, which in any finite time converge continually
to equality, and before the end of that time approach nearer
the one to the other than by any given difference, become
ultimately equal."

It was the calling, those results true which are only ap-
proximations indefinitely near the truth, that gave the au-
thor of the Analyst so much advantage in exposing the
errors in the metaphysics of the fluxional calculus ; and it
was very inconsiderate in Philalethes (supposed to be Dr.
Jurin) to argue that the error occasioned by neglecting a
certain very small quantity did not affect the result of any
operation : — that did not in the least tend to overthrow the
arguments adduced by the author gf the Analyst, since it
was the error in principle that he struck at, and not the
quantity of error that the making use of a false principle
might produce.

The conclusions obtained by the method of fluxions are
not absolutely true, nor did Newton ever consider them as
such ; they are approximations, which produce no sensible
errors; and had his host of defenders proceeded no further
than this, all the arguments that could have been brought
forward against this method must have vanished.

But instead of giving up what was evidently untenable,
all the varied arguments which imagination aided by science
could suggest, were brought forward in order to get rid of
the difficulties which Berkley had pointed out, but without
effect; for truth is at all times consistent with itself, and
what is once wrong can never be proved to be right.

Newton was desirous of determining the areas of curvi-
linear figures : this was at all times a great desideratum,
and hadT exercised the talents of philosophers in all ages.

The

On prime and ultimate Ratios, ISO

The first method which the ancients made use of for this
purpose was the method of exhaustions : an example of the
use of this method is given by Euclid in the second proposi-
tion of his twelfth book, where he compares the circle and
square, and proves that any two circles are to each other
as the squares on their diameters : the same method was
also made use of by Archimedes in determining the quadra-
ture of the parabola. The argument here made use of is
called reducth ad absurdum, which, though strictly logical,
is often tedious, because every proposition must be divided
into two cases, in one of which it must be shown that the
former of the two quantities to be compared is not greater
than the latter ; in the other, that it is not less, it was
with a view of shortening this mode of reasoning, that Ca-
valeriiis invented the method of indivisibles : in this method,
every line is supposed to be made up of a number of other
lines whose lengths are indefinitely short, and every curvi-
linear figure is considered as a polygon of an indefinite
number of sides : — these principles were in many cases
extremely easy and convenient, and produced true results;
they, however, often led their followers into perplexities,
and sometimes into error.

It was to avoid the tediousness of the method of ex-
haustions, and the errors in the method of indivisibles, that
Newton invented his method of prime and ultimate ratios ;
the principles of which he laid down in the first lemma of
the Principia, as observed above. Several eminent mathema-
ticians have endeavoured to demonstrate Newton's lemma:
it however certainly admits of no direct proof; it is itself a
definition, and requires only to be illustrated, or explained.
By introducing the doctrine of motion into geometry,
much has been effected. Newton employed his method
of prime and ultimate ratios to the quadrature of all kinds
of spaces, by supposing one or more of the sides of the
figure to be in motion, and to generate those figures by the
motion of their extreme points. The application to right-
lined figures was natural and easy; and to apply it to a
square, we will suppose that the square is generated by the
motion of two right lines perpendicular to each other, and
that move parallel to two other right lines placed at right
angles.

Let x denote the length of each side at any given posi-
tion of those lines, and let i be the increase, in the length
of each side, caused by the motion of the two moveable
sides; then, x+x will be the length of each side so in-
creased,

1 90 On prima and ultimate Ratios,

creased, and the fluxion of the area is (#+ i)2— #4; that
is = cjxx-\-x2. Now in order that we may neglect i,;
without affecting the result of the operation, we must sup-
pose that x is a quantity less than any assignable, or that
it is only in a nascent state : according to this supposition,
the error, by neglecting xl, will be extremely small, and
will no way affect the fluxionary increase of the square ;
but, except x vanishes, and that would annihilate the
fluxional increase altogether, we are obliged to acknowledge
that the result is not strictly and logically true.

Again, let x and y denote the sides of a rectangle, and,
by the motion of those sides, let them become aj + iand
y+y) then, the fluxion of the area of this rectangle will
be (x-\-x) X (y+y) — XV, or = xy+iy + xy. Here, also, that
the rectangle iy .may be neglected, i and z/ must be inde-
finitely small, or in a nascent state; but even then an error
is committed, and, however trifling it may be, the result
will not be strictly and geometrically true. Fluxions, then,
do not produce results which are exactly true; but, as was
observed above, they give us approximations differing from
the truth by less than any assignable quantity, however
small, and, therefore, may be esteemed as true with respect
to their practical conclusion. To proceed further would
be of no use: the application of those principles to curvi-
linear spaces is given in every book of fluxions. What has
been given above may probably be of some use to students,
as it may possibly serve to elucidate the principles of a
science, which has been the instrument by which almost all
the improvements in philosophy have been brought to
light. The principle of such a science ought to be esta-
blished upon a sure foundation ; and should what has been
said be of any use in removing the cavils that have been
made against the fluxionary calculus, a service will be done
to philosophy, and the writer of this essay mav at least
hope to be excused for endeavouring to contribute some-'
thing towards elucidating the elements of those very use-
ful but too much neglected studies.

I remain, sir,

Your very humble servant,

Boston, Sept. 10, 1810. W. MARRAT.

XXXV. Com'

[ 191 ]

XXXV. Comparative Examination of the Mucous Acid

formed by the Action of the Nitric Acid: \st9 on the

Gums; Qdly, on the Sugar of Milk. ByM. Laugier*.

JYjL Vauquelin ascertained by his experiments on gam
arabic and gum tragacanth the existence of a very consi-
derable quantity of lime in these substances.

The perusal of his experiments suggested the following
reflections : —

1. What becomes of the lime contained in these gums
when we treat them by the nitric acid^ with the view of
procuring mucous acid ?

2. Is it not combined with the oxalic acid which is
formed almost at the same time with the mucous acid ?

3. The oxalate of lime being more insoluble in water
than the mucous acid, is it not precipitated with this acid,
when we wash the residue after the operation ? and does it
not alter in a sensible manner its properties ?

4. What ought to be the means of ascertaining the pre-
sence of the oxalate of lime in the mucous acid obtained
from the gums, and of separating this calcareous salt from
the acid whose purity it injures?

With a view to resolve these questions, I undertook the
following experiments :

I digested with eight parts (480 grammes) of pure nitric
acid at 360° one part (60 grammes) of gum tragacanth ;
I heated the mixture until it was reduced into a honey-like
substance, and I added a sufficient quantity of water.

The latter would not dissolve a white pulverulent matter,
which I gathered on a filter, and which when dried in the
air weighed {) grammes and a half, and this was mucous
acid. The liquor containing the soluble portion of the
mixture was of a yellow colour. I evaporated it, and did
not take it from the fire until I saw if covered with a slight
pellicle which was formed at its surface : by and by, upon
cooling, the liquor deposited a great quantity of crystals,,
some in lamince, others in needles very well defined as
oxalic acid. With the view of separating this last acid
from the mucous acid, I poured upon the mixture alcohol
at 40°, which dissolved the oxalic acid without touching the
mucous acid which I collected on a filter. The second
portion of mucous acid weighed two grammes 0*]0. The
.alcoholic solution furnished, on a gentle evaporation, a co-

• Anmi-Ui de Chimie, tome Ixxii. p. 81.

loured

192 Comparative Examination of the Mucous Acid

loured mass, which I redissolved in water in order to ob-
tain whiter and purer crystals.

The mother waters of this second portion of mucous
acid and of oxalic acid, contained a mixture of oxalic and
malic acids, which I separated from each other, by means
which I shall not detail, because they would lead me away
from the principal object of my experiments,

The first portion of mucous acid which I obtained
weighed nine grammes and a half, it was very white; when
dried it had the grumous appearance of starch. This was
the substance which I employed in my experiments. I re-
jected the second portion, because it did not seem to be of
the same purity.

With the view of ascertaining the presence of the oxalate
of lime in this mucous acid, T mixed one part of the nitric
acid as above, with ten parts of distilled water, and poured
this mixture upon the nine grammes and a half of mucous
acid. I exposed the whole to a heat of 40 or 50 degrees
during twice 24 hours, taking care to stir it from time to
time, to facilitate the action of the solvent. I decanted the
supernatant liquor, in which ammonia immediately pro-
duced the precipitation of a white earthy salt,' in silky fila-
ments, which had all the physical properties of the cal-
careous oxalate.

A second portion of weak nitric acid, added to the sedi-
ment of the foregoing liquor, and left to itself during the
same time, furnished with ammonia a new quantity of
oxalate of lime.

It required eight portions of weak nitric acid, successively
added, to clear entirely from oxalate of lime the mucous
acid submitted to the experiment. Every time the am-
monia, when mixed with the decanted and filtered liquor,
separated from it a quantity of calcareous oxalate, the pro-
portion of which diminished at each digestion in a striking
manner. The ninth portion exhibited but very minute
traces of it.

The eight precipitates united together gave a total weight
of two grammes three decigrammes.

It was important to ascertain, if this substance, which
was foreign to the mucous acid, and whose appearance and
physical characters appeared to me to be similar to those
of the oxalate of lime, was really this calcareous salt.

With this view I boiled this substance, with a saturated
solution of carbonate of potash ; and when the reciprocal
decomposition of the two salts seemed to me to be com-
pleted, I collected on a filter the portion which was de-
posited,

formed ly the Action of the Nitric Acid. 1 93

posited. This sediment, not so white as the first calcareous
salt, and in coarser powder, was dissolved with great effer-
vescence in the nitric acid. Its solution, which was of a
sharp pungent taste, was not precipitated by ammonia itself,
but very abundantly by the oxalate of ammonia.

The liquor which floated above this carbonate of lime,
and which contained an excess of carbonate of potash, was
supersaturated by the acetic acid and evaporated to dryness;
the residue was treated by alcohol, in order to separate the
acetate of potash from the oxalate of the same base which
is not soluble in this liquid. The mixture when heated for
a few moments was thrown on a filter, where the oxalate of
lime remained, whereas the alkaline acetate passed through
with the alcohol.

The portion insoluble in this liquid was dissolved in di-
stilled water : a drop of this solution mixed with half a
spoonful of lime water, formed in it a. pulverulent precipitate,
evidently oxalate of lime; and the same solution furnished
by evaporation crystals of oxalate of potash.

The experiments which I have described, cannot leave
any doubt as to the nature of the calcareous salt, the pre-
sence of which alters the purity of the mucous acid ob-
tained from gum tragacanth.

The same experiments repeated on gum arabic, and on
that which is known in commerce by the name of gum of
Bassorah, which is insoluble in water, furnished me with
nearly the same results.

I observed, that in proportion as the mucous acid lost by
the nitric acid the oxalate of lime which rendered it impure,
it assumed a more flaky appearance.

Scheelej to whom we owe the^discovery, at first called it
saccho- lactic acid, because he obtained it by treating the
sugar of milk with nitric acid. This denomination ceased
to be convenient, the moment it was proved that it might
be procured from the gums by a similar process ; and this
induced M. Fourcroy to substitute the appellation of mu-
cous acid for that of saccho-lactic acid.

But is the mucous acid furnished by the sugar of milk
perfectly similar to that which we obtain from the gums ?
rs it altered like the latter by containing a remarkable
quantity of oxalate of lime; or rather does it contain but
the smallest quantity of this calcareous salt; or, finally, is it
totally deprived of it ? It appeared to me to be interesting
to find out a solution for these questions, and I set about
applying the process just described to the mucous acid fur-
nished by the sugar of milk.

Vol. 36. No. T49. Sept. 1810. N I took

lQi Comparative Examination of the Mucous Acid

I took, in consequence, one part of sugar of milk, which
I boiled with eight parts of nitric acid of the same strength
with the foregoing. I separated by decantation the first
portions of mucous acid which were formed, and I added
to the residue a new quantity of nitric acid. A second
portion of mucous acid was deposited, which when united
with the first gave a total weight of twelve grammes, or the
fifth part of the sugar of milk submitted to the experiment.

I remarked that, after washing, this mucous acid, di-
luted in water, had an appearance equally flaky with that of
the gum when it was deprived of its oxalate of lime by
the weak acid. This remark inclined me to think that
this acid was much purer than that of the gum, and this
opinion was confirmed by the nitric acid having had no
action on it. It did not take up from it the smallest quan-
tity of oxalate of lime, after a long continued digestion, for
the ammonia did not take the slightest effect on the super-
natant liquor.

In addition to this, what leaves no doubt as to the per-
fect purity of the mucous acid of the sugar of milk, is, the
circumstance of its easily and entirely dissolving in boiling
water. This entire solubility in boiling water proves that
it enjoys a greater purity than the mucous acid of gum,
even when the latter has been purified by the means above
mentioned: in fact, the Tatter, well freed from oxalate of
lime, still leaves, when it is boiled with distilled water, an
insoluble flaky matter forming the 0*06 of its weight,
which dries into a gray horny semitransparent body, similar
in appearance to the mucous substance which connects the
molecules of animal concretions, although on burning
coals it does not furnish the ammoniacal and fetid smell
of animal compounds, and which furnishes on calcination
carbonate of lime. The too small quantity which I ob-
tained of it did not admit of my making experiments which
would have thrown more light on the nature of this body.

From the facts detailed in this memoir, we may draw
the following consequences :

1. There exists a very remarkable difference between the
mucous acid procured from gums, and that which we ob-
tain from the sugar of milk by the action of the nitric acid.

2. This difference consists in ahe first being constantly
altered by the mixture of a quantity of oxalate of lime in
proportion to that of the earth which the gums contain,
whereas the mucous acid of the sugar of milk does not
offer the slightest trace of this calcareous salt, and seems
perfectly pure.

3. We

formed by the Action of the Nitric Acid. 1 9$

3. We may procure the mucous acid from the gum in
the same state of purity, by a very simple process, which
consists: 1st, in taking from it, by successive digestions in
very weak nitric acid, the whole of the oxalate of lime
which it contains: 2d, in boiling it in water, which dis-
solves it without dissolving the. flaky matter which the ni-
tric acid does not take up.

4. When thus deprived of substances foreign to its na*
ture, the mucous acid of gum is entirely similar to that of
the sugar of milk, enjoys all the properties which charac-
terize this acid, and maybe employed with .the same advan-
tage in the most delicate experiments which require that
this acid should be of a perfect purity.

I am convinced that there is a circumstance in which
the mucous acid obtained from gum is mixed with mucite
of lime, instead of the oxalate which I have mentioned.
This happens when we substitute in the preparation of the
mucous acid, the nitric acid diluted in water, instead of the
Concentrated nitric acid, and consequently when we con-
duct the operation slowly instead of hastily. It is easy to
ascertain the difference of the results which we obtain.

If we employ the weak acid, the mucous acid is at first
produced alone, and it is precipitated, carrying with it the
lime, with which it forms a salt nearly insoluble, and we
may separate it from the mixture before the formation of
the oxalic acid, which requires the concentration of the
acid. If, on the contrary, we make use of concentrated
nitric acid, the formation of the two acids, although always
successive, is very thick ; and we may easily conceive that
in this case the oxalic acid, as soon as it is formed, seizes
the lime, in virtue of the more powerful affinity which it
exercises on this earth.

I shall add another fact which led me to recognise a
singular property in mucous acid, which I intend to ex-
amine more in detail than I am able to do at present.

When we gently evaporate to dryness the solution of
pure mucous acid made in boiling water, without separat-
ing the crystalline sediment which is formed during eva-
poration, we observe that the moment there is no more
liquid, the crystals become yellow, then brown, and are
converted into a viscous tenacious-like matter, which un-
dergoes avkind of fusion, aud becomes very hard on cooling.
The mucous acid which has undergone this change, has a
much more acid taste than usual ; it. is infinitely more
soluble in water, — has become entirely soluble in alcohol,
and has therefore changed its properties in part. I thought

N2 at

1 96 On the Prussic and Prussous Acids.

at first that I had thus produced the conversion of the
mucous acid either into malic acid or tartarous acid ; but
the experiments which I made to verity this opinion, do
iK)i vet appear sufficient to permit me to venture an opinion
on the nature or' the change which takes place in the ex-
periment which I have described.

XXXVI. On the Prussic and Prussous Acids. By Mr.
R. Porrett, Junior, of the Tower.*

v CONSIDERABLE differences of opinion exist among the
most celebrated chemists respecting the composition of the
prussic acid; some agreeing with Fourcroy and Vauquelin,
that Oxygen is one of its component parts, and others with
Berfholletand Proust, who dispute its presence. Mr. Proust,
in his history of the -prussiates, asserts, "That there is no
fact that indicates oxygen in- make a part of this acid, and
that from the well-known affinities of its three elements,
added to the circumstances under winch it is formed, it
can scarcely be thought that it does.'* This difference of
opinion implies a want of some decisive experiments, which
may set the question for ever at rest ; and those which I
am coins; to relate I am induced to think are of that de-
scription.

Some time back, F proposed to myself the discovery of
a method ot preparing a triple prussiate of potash, in a
pure state, which should be free from the objections to
which the processes in general use are subject. In reflect-
ing on the means most likely to attain this end, it occurred
to me, that I should succeed if I decomposed prussiate of
iron by double elective attraction rather than by single,
employing, instead of a pure potash, that alkali, in com-
bination with a substance uniting the properties of solu-
bility when combined with potash, strong attraction for
oxide of iron, and insolubility when unittd to that oxide.
The only substances I could think of possessing all these
requisite properties were the succinic acid and sulphur ; as
the high price of the former precluded its' use for ihis pur-
pose, I determined to employ the latter. I therefore took
oni- ounce of dry sulphuret of potash, and one ounce and a
half of the best prussian blue, previously well washed and
powdered, and put them into a Florence rla?k, two thirds

* From Traxtactwn* of the Society fur the Encouragemeyit of Arts, Manv-

s, and Commerce, vol. xxvii. The Society volcd their silver medal

to Mr. Porrett for this communication.

• filled

On the Prussic and Prussous Acids,

107

filled with distilled water; a disengagement of sulphuretted
hydrogen, of ammonia, and of caloric immediately took
place. The materials were boiled slowly together for three
hours, occasionally replacing the water which evaporated.
The whole was thm thrown on a filter; what remained on
the filter was black, and consisted of sulphuret of iron and
un decomposed prussiate of iron. The liquid that passed
through, I found on trial to consist of triple prussiate of
potash, and hydroguretted sulphuret of potash. In order to
complete the decomposition of the latter, I boiled the liquid
again, for the same time as before, with another half ounce
of prussian blue, and when cold filtered it. The filtered
liquid (A) was now nearly colourless, and free from hydro-
guretted sulphuret. On pouring a little of it into a solu-
tion of oxy-sulphate of iron, I was very much surprised to
find that" solution changed to a deep blood-red colour,
without any precipitate ensuing, instead of forming with
i£ a precipitate of blue prussiate of iron. So unex-
pected a phenomenon determined me to undertake an ex-
amination of this liquid ; with this view I subjected it to
the action of the chemical agents mentioned in the follow-
ing table.

Table I. with Liquid A.

Chemical Agents.

Paper stained withl
turmeric J

Paper stained with "1
litmus j

Potash ,

Lime ,

Diluted sulphuric acid

Nitric acid (pure) . . .

Oxy-muriatic acid . . .
Muriatic acid (pure) .

Muriate Parvus

Tincture or" galls

Nitro-muriate platina

Effects.

No change of colour.

Do.

Do,

{No disengagement of ammonia,
nor anv apparent change.
Do. ' Do.

{An expulsion of sulphurous acid;
the liquid becomes' slightly
opalescent.
{The acid assumes a red colour, but
this effect is not permanent.
This acid loses its smell.
No change.
A while precipitate.
No change.

{A heavy brilliant ochre, yellow
precipitate.
N 3 Muriate

198

On the Prussic and Prussous Acids.
Table I. — (Continued.)

Chemical Agents.

Effects.

Muriate gold

Dark olive brown precipitate.

/"A precipitate at first white, but

Nitrate silver. ,..,..

< quickly passing to yellow, red,

V ' and lastly to brown.

Sulphate silver

f A dull white or stone-coloured
\ precipitate.

Oxy -nit rate mercury .

A white precipitate.

Oxy-nitrate lead

A white precipitate.

Supersulphate copper

A dull white precipitate.

Muriate bismuth

No precipitate.

Sulphate iron

No change.

Oxy-sulphate iron . . .

f The solution assumes adeepblood-
\ red colour. No precipitate.

The effects of the sulphuric acid and of the muriate
barytes clearly proved the existence of sulphite of potash
in the liquid, while that of the oxy-sulphate of iron indi-
cated the presence of some other principle to which the
liquid was indebted for its peculiar characters ; the separa-
tion of this principle in a' pure state became therefore a
necessary preliminary operation to its examination : after
a few trials I succeeded in effecting this separation. The
following is the process I employed.

The liquid was evaporated by a gentle heat to dryness ;
upon the saline residuum alcohol was poured till it ceased
to extract any thing : by this means the whole of the sul-
phite and sulphate of potash was left behind, and the alco-
hol when filtered held in solution that part only which had
the red tingeing property with solutions of iron. The alco-
hol was now got rid of by distillation, and the salt it left
in the retort was redissolved in water. This solution (B)
gave the following results with the different metallic so-
lutions.

Table II. with Liquid B.

Metallic Solutions.

Effects.

Nitro-muriate platina

I

Muriate gold !

precipitate similar to that in
"able I. but in a smaller quan-
ity, and longer in forming.
/ Light olive precipitate, some gold
l educed. Ni

(A pre(
Tabl
tity,

On the Vrussic and Prussous Acids,
Table II. — (Continued.)

199

Metallic Solutions.

Effects.

Nitrate silver

f A grayish white precipitate, not
I changing colour.

Sulphate silver ......

A clear white precipitate.

Nitrate mercury

A copious white precipitate.

Oxy-nitrate mercury .

A white precip. in small quantity.

Nitrate lead

No precipitate.

Oxy-nitrate lead

No precipitate.

Superacetate lead

No precipitate. ,

Hyperoxymuriate lead

A slight white precipitate.

Supersulphate copper

A dull white precipitate.

Muriate tin

No precipitate.

Muriate bismuth

No precipitate.

Sulphate iron

No change.

Oxy-sulphate iron . . .

Same as Table I.

Oxy-sulphate manO

ganese J

Sulphate zinc

f The crimson colour disappears;
\ no precipitate.

No change.

Nitro-muriate cobalt .

No precipitate.

Nitrate nickel

No change.

It is necessary to remark, that in the preceding table, as
wel) as in Table I, several of the nitrates and muriates were
slightly reddened, though not in a degree to be compared
with the oxy-sulphate of iron. I have not noticed this in
the table,, because I am not certain whether this effect was
not owing to a minute portion of oxide of iron which might
have been introduced into those solutions by the acids em-
ployed to make them, as both the nitric and muriatic acids
of commerce generally contain some; an excess of nitric
acid, even if pure, might also cause this effect, as Table I.
may convince us. The solutions with which this effect
occurred to me were those or' bismuth, silver, mercury,
lead, cobalt, gold, and platina.

The liquid B is not altered by exposure to the air.

Its effect on oxv-sulphate of iron is the same, whether
this sulphate is neutral, or contains an excess of acid, or is
supersaturated with carbonate of ammonia.

Sulphuric acid destroys the colour produced on oxy-sul-
phate of iron, provided the three liquids are in a concen-
trated state. If there is. much water present, no change
ensues.

Having obtained the tingeing principle B, separate from
N 4 the

200 On the Prussic and Prussous Acids.

the other salts with which it was contaminated, I asked
myself to what were its formation and the simultaneous dis-
appearance of the prussic acid, during the second ebullition,
owing? I could imagine but five causes for this that were
likely to have been efficient, concerning each of which I
made a question to be resolved by experiment, viz.

Ouestion I. Was it owing to the complete separation of
the oxide of iron from the triple of prussiate by the sul-
phur, and the subsequent decomposition of the simple prus-
siate by the heat of ebullition long continued ?

Question IT. Was it owing to the action of the sul-
phurous acid produced ? v

Ouestion TIT. Was it owing to the action of the sulphu-
retted hydrogen ?

Ouestion IV. Was it owing to a combination of the
prussiate of potash and sulphur?

Question V. Was it owing to the de-oxidation of the
prussic acid, by the hydroguretted sulphuret?

To answer jhe first question, it is only necessary to at-
tend to the results afforded by long-continued boiling of
the simple prussiate of potash. I shall state these results
as I find them recorded by professor Proust.

They are carbonate of ammonia, carbonate of potash,
and some simple prussiate that escapes decomposition, even
after four or five successive distillations : there is, therefore,
no analogy between the products of this experiment and
the liquid A; for, had the latter contained carbonate of
potash, it must have changed turmeric paper brown ; had
it contained carbonate of ammonia, it must have done the
same, and likewise have given out ammoniacal gas when
potash and lime were added ; it must also have turned blue
the solution of copper; 'and had it contained prussiate of
potash,, it must have produced prussiate of iron when added
to the green sulphate of that metal : it will be seen by re-
ferring to Table T. that none of these effects were produced.
Were further evidence necessary of the dissimilarity of the
two liquids, it might he mentioned that professor Proust
poured alcohol on the saline residuum of his distillation of
the prussiate, which took up a part that he found to be
prussiate of potash : had any of the tingeing salt B been
present, the alcohol must have dissolved that likewise, and
it could not have escaped his observation. We have, there-
fore, ample grounds for negativing the first question.

In order to answer the second question, I passed sul-
phurous acid gas for a long time through a solution of tri-
ple prussiate of potash; the prussic acid was expelled, and

sulphite

On the Prussic and Pr us sous Acids. 201

su.pbite of potash formed ; but this sulphite was not mixed
with any tingeing salt. On the supposition that the disap-
pearance of the prussic acid, in the liquid A. might have
been owing to its having been expelled entirely by the sul-
phurous acid, and that the tingeing liquid resulted from the
mutual action of the other principles, namely, the oxide of
iron and hydroguretted sulphuret of potash; I subjected a
mixture of these materials to long boiling, but could not by
this means produce a liquid that tinted oxy-sulphateof iron
red. Sulphurous acid gas, passed through water in which
prussjan blue was diffused, did not in the least affect that
compound. These experiments completely refute the opi-
nioiton which the second question was grounded.

To enable me to replv to the third question, I passed sul-
phuretted hydrogen gas for several hours through a solu-
tion of triple prussiate of potash, on which it was found to
have no effect.

We shall be little disposed to allow that there is any
foundation for the fourth question, when we consider the
circumstances of the last -mentioned experiment, In which
sulphur in the state of the most minute division was of-
fered to the triple prussiate, without any combination en-
suing; and also when we compare the effects of the me-
tallic soluhons in Table II. with those which 'would ensue
with liquids containing sulphur. But, if any doubt should
still be entertained on this subject, the following experi-
ment will perhaps remove it: Into a solution of prussiate
of mercury throw some pieces of phosphuret of lime, the
oxide of mercury of this prussiate will thus be reduced and
separated from the liquid which is to be filtered ; some of
this liquid poured into carbonate of iron turns it red, the
red colour soon disappears, and a white precipitate begins
to form ; this white precipitate soon changes to green,
and if a little nitric or oxy-muriatic acid be now poured
upon it, it becomes a perfect blue prussiate of iron. This
experiment, in which a liquid turning a solution of iron
red was produced without the employment of a particle of
sulphur, goes very far to negative our fourth question;
and when considered in conjunction with the preceding
ones, we can hardly do otherwise than dissent from the
supposition which gave rise to that question.

But if the experiment last adduced tends to refute the
fourth question, it very strongly supports the fifth ; for the
changes of colour observable were undoubtedly owing to
successive stages of oxidation by the contact of the atmo-
sphere. In confirmation of this question, it may likewise

be

202 On the Prussic and Prussous Acids,

be asserted, that the long boiling with the hydrdguretted
' sulphuret is a powerful de-oxidating process. But it will be
said to me, If it is really true that the prussic acid has been
deoxidated by this process, you ought to be able to recom-
pose that acid from the solution B by oxidation. This
struck me very Vorcibly ; and being anxious to give this
last proof of the truth of my deductions, I attempted the
recom position of this acid by several oxidating processes
for some time without success: 1 had at last, however, the
particular satisfaction of succeeding completely by the
agency of nascent hyper-oxy muriatic acid. The method
I employed was the following :

A little hyper-oxymuriate of potash was put into the bot-
tom of a glass tube. Over this some of the liquid B mixed
with a few drops of diluted sulphuric acid was poured. The
heat of a candle was then applied to the bottom of the tube ;
and as soon as a violent action commenced, the heat was
withdrawn : by this process the v prussic acid was repro-
duced, and was proved beyond the possibility of a doubt
by the formation of blue prussiate of iron, when poured in-
to a mixture of green and red sulphate of that metal. Blue
prussiate may also be produced at once, by substituting for
the diluted sulphuric acid, a solution of green sulphate of
iron, with excess of acid.

Having thus succeeded in proving that the tingeing prin-
ciple of the liquid B was sub-oxidized prussic acid, my next
object was to obtain that principle in a free state : for we
roust recollect that we have hitherto considered it onlv in
combination with potash, with which it formed a neutral
salt ; this circumstance gave me reason for supposing it an
acid, and I therefore determined to attempt its separation
by abstracting its base by a stronger acid. The following
was the process I employed for the purpose.

The liquid B was evaporated nearly to dryness, and put
into a retort with diluted sulphuric acid ; a receiver was then
adapted to it, and about two- thirds of, the liquid distilled
over by a gentle heat; what remained in the retort was sul-
phate of potash. The receiver contained a colourless liquid,
with a faint, sour, disagreeable smell, and a decided acid
taste. This liquor I have named, in conformity with the
principles of the new nomenclature, prussous acid, and its
salts prussileSf of which the liquid B contained one in so-
lution, namely the prussite of potash.

The effects of the prussous acid on the earthy and me-
tallic solutions, as far as I have tried them, are noted in the
following table.

Table

On the Prnssic and Prussous Acids.
Table III. with Prussous Acid.

203

Chemical Agents,

Effects.

Muriate lime ,

Muriate barytes .....

Muriate gold ,

Sulphate silver. . . .1
Nitrate silver . . . ,j
Prussiate mercury . . ,
Nitrate mercury ....
Oxy-nitrate mercury .

Oxy-sulphate iron ...

Nitro- muriate platina
Nitrate lead ,

Oxy-nitrate lead

Hyper-oxy muriate lead

Super-sulphate copper
Muriate bismuth . .^
Nitrate nickel
Muriate tin . .
Nitrate cobalt. •„• . . )■
Sulphate iron .
Sulphate manganese
Sulphate zinc .

J

No change. '

No change.

The gold precipitated metallic.

Copious white precipitates.

No change.

Copious grayish white precipitate.

Very slight precipitate white,

{Solution turns blood-red. No
precipitate.
No precipitate.
No change,
f Solution becomes red, but hardly
any precipitate formed, unless
heated, in which case a copious
white precipitate ensues. The
^ red colour disappears, a rapid
action takes place between the
two liquids, and some of the
nitric acid of the solution is de-
composed,
f A slight precipitate, probably of
\ muriate of lead.
Solution becomes slightly turbid.

No precipitates.

I cannot conclude this part of* my memoir without giv-
ing a more simple and expeditious process for preparing
prussite of potash, than that which I at first discovered.

It is the following :

Pour a solution of prussiate of mercury into hydrogu-
retted sulphuret of potash, till the mutual decomposition
of the two liquids is completed ; prussite of potash is in-
stantly formed, and may be separated by filtration from the
solid combination of the sulphur and mercury.

I wish

204 On the Prussic and Prussous Acids.

I wish also to observe, that the proportion of prussian
blue I have mentioned for boiling with the sulphuret is
much larger than is necessary, as 1 have since succeeded in
obtaining prussite of potash when the proportion of prussian
blue was only equal to that of the sulphuret, but long boiled
with the latter in two distinct and' equal portions. The
prussite of potash thus obtained is, however, mixed with a
much larger quantity of hydroguretted sulphurct than when
a greater portion of prussian blue is employed.

Whether the prussous acid can be applied to any use,
time and future experiments must decide. It appears to me
to be a very delicate test of silver and of iron in solution. •

The preceding experiments, by proving the presence of
oxygen in prussic acid, give it a stronger claim than it be-
fore possessed for being placed among the acids.

The prussous acid possessing stronger acid properties
than the prussic is a curious, though not a solitary, instance
of the effect of oxygen in diminishing acidify, when its
quantity exceeds a certain fixed proportion; in this respect
the prussic acid is analogous to the oxy-muriatic. -

To recur to the attempt which gave rise to the researches
that are the subject of this memoir, I beg leave to state,
that I have succeeded in producing pure triple prussiate of
potash, by stopping the process before the change which
produced the prussite ensued, and by subsequent purifica-
tion of the lixivium from sulphates and sulphites, by acetate
of barytes ; from sulphur by acetate of lead ; and, lastly,
from the acetate of potash thus formed by crystallization 5
but on account of the complication of this process, 1 hesi-
tate to recommend it for general use.

Tower, London, April 21, 1809. ROBERT PoRRETT, Jun.

p.S. — It is essential to the success of the experiment, in
which the prussicacid is regenerated from the liquid B by the
nascenthy per-oxygenized muriatic acid, that the excess of
acid remaining in the liquid, after the oxygenizing process,
should be neutralized by an alkali previous to pouring it into
the solution of iron, which should likewise be perfectly
neutral.

May S, 1S09. PiOBERT PoRRETT, Jlin.

XXXVII. Memoir

[ 205 ] ,

XXXVII. Memoir on the Muriate of Tin. By M. Be-
raid, Ex~ Projector of Chemistry in Mmtpellier.

-L he preparation on a large scale of muriate of tin has fur-
nished me w ith the opportunity of observing some interest-
ing facts. They will serve as appendages to those which
have been described by various writers, and perhaps may
tend to accelerate the discovery of an uniform and certain
method of preparing and using the composition for dyeing
scat let, which is a kind of salt of tin.

The solution of tin by the muriatic acid, as described by-
various authors, and as practised by Baume, is operated
by pouring on one part of the metal in a state of very mi-
nute division, lour parts of common muriatic acid, and as-
sisting the chemical action by the heat of a Band-batb. The'
water, which serves as a vehicle to the acid, is decomposed,
the oxygen oxidizes the metal, which is then combined with
the acid, while the hydrogen is liberated in the gaseous state,
carrying off with it some particles of the metal employed,
which render it very fetid. But the action is slow, and the
solution is effected in an imperfect manner. I observed
that a verv great part of the acid employed was evaporated
and lost ; and that if we wished to operate the entire solu-
tion of the metal, we must not only add acid in the place of
that which was evaporated, but also keep up the action by
heat for several days. I tried to perform this operation in
the cold way, and two months were insufficient. Bayer and
Charlard, in their inquiries upon tin, employed six months
in the operation. , r

M. Chaptal assists the chemical action between the mu-
riatic acid and the tin, by placing, when he has prepared this
,acid,the metal in the vessels ofWoolPs apparatus, m which
was the water which might to receive the vapours. The
heat which is extricated produces the best effect, and the
action becomes very brisk towards the end of the operation.
But *his ingenious contrivance still leaves something to be
desired, in so far as the acid only dissolves the fourth of its
weight of tin, and. we must terminate the solution by other
means.

We may operate the solution of tin still better by receiv-
ing into a large receiver, in \\ hich we have introduced a suf-
ficient quantity of the metal in minute division, the vapours
of muriatic acid, which are liberated from a mixture of mu-
riate of soda in powder and of sulphuric acid weakened to
the 40th degree of Baume's areometer. On operating a

simple

206 On the Muriate of Tin.

simple distillation in this manner, the vapours of muriatic
acid are very easily condensed and combined.

If we direct vapours of oxygenized muriatic acid into a
vessel containing tin and common muriatic acid, the so-
lution takes place perfectly, and in a short time. The acid
at 20° then takes up one third of its weight in tin.

I tried various mixtures of muriatic acid and nitric acid,
from one- sixth part of the latter up to one-tenth ; all of
them acted on the tin with extreme heat and violence, the
substances being forcibly ejected from the vessel. One part
of nitric acid, or the aqua fortis of commerce, at 35° of
Baume's areometer, and twelve parts of common muriatic
acid, at 20°, form a mixture very well adapted for the so-
lution of tin, which is thereby operated in a very short
time. This acid when mixed takes up about one-third of its
weight of tin, and the solution extends to the 45th degree.

I tried to make the action of the muriatic acid, and that
of the atmospheric air, alternately concur on tin divided into
small pieces, in operating its solution, and I succeeded com-
pletely. For this purpose I filled a large glass saucer with
the tin, and covered it with muriatic acid at 20° for a few
hours ; I then poured the acid into another vessel, and it had
already ascended to the 25th degree. The tin becomes black
the moment it comes in contact with the air. There is an
absorption of atmospheric oxygen gas, an extrication of ca-
loric, which renders the metal very hot, and a lighted candle
when plunged into the saucer is speedily extinguished. As
soon as the vessel began to cool, I replaced the acid, which
acted with new vigour, and in a short time was as high as
35°. I withdrew it again, in order to give the action of the
air to the tin, and I rtplaced^it in the same manner, that it
might once more act. I repeated this operation from time
to time until the action ceased. In two days the solution
was at 45°, which it would attain e,ven in one day if we em-
ployed a series of saucers filled with tin: while the acid acts
upon some of the vessels, the air acts on the rest, and thus
the operation is never interrupted.

The muriatic solution of tin, when recent, combines
speedily with oxygen gas from the atmosphere, as Messrs.
Pelletier, Guyton Morveau, and other celebrated chemists
have observed. It is sufficient to turn upside down a bell-
glass, full of atmospheric air, on a capsule or saucer filled
with this liquor, in order to see the latter ascend Into the
bell-glass until all the oxygen be absorbed. The absorption
is still more rapid, and becomes almost total in a short time/

when

On the Muriate of Tin. 207

when the bell-glass is filled with pure oxygen gas. In order
to facilitate the combination of the oxygen gas with this re-
cent solution, I made to pass through it a great quantity of
atmospheric air, by means of a pair of bellows, the pipe of
which goes to the bottom of the liquor. When it is not
sufficiently saturated with tin, it takes a new portion of it
in proportion as it absorbs the oxygen from the atmosphere.
The oxygenated muriatic acid gas is absorbed by this so-
lution with great energy, as Pelletier has very aptly observed.
He had even proposed the solution thus saturated with ox-
ygenized muriatic acid gas for dyeing scarlet. J requested se-
veral artists to try it, but none or them adopted it. It should
seem that the combination of atmospheric oxygen 2;ives it
nearly the same properties with those of oxygenized muri-
atic acid gas. When it has absorbed much of the oxyge-
nized muriatic acid gas, it becomes proper for dissolving a
new quantity of tin ; and as soon as it has dissolved it, again
its state becomes changed, having become capable of ab-
sorbing more oxygen.

The muriatic solution of tin at 45° of density gives upon
evaporation crystals of muriate of tin. The crystallization
takes place the more easily the less recent the solution is,
or the greater the quantity of oxygen which the solution
has absorbed.' The mother water, which swims above the
crystals, is of a very great density, particularly after several
crystallizations. The density is still more considerable, if
we set it to evaporate before exposing it to the air. It is
even sometimes slightly smoking, and may then furnish
crystals by diluting it with pure water. A flask containing
14 parts of distilled water, contained 28 parts of mother wa-
ter coming from the first crystals. The same flask con-
tained 31 parts, when this same liquor had given by con-
centration several layers of crystals. These mother waters
are capable of being combined with the oxygen of the at-
mosphere, when the solution has not been previously satu-
rated with it. It is sufficient to expose them to the air, or
jto act with a pair of bellows, as already pointed out with re-
gard to the simple solution. This combination produces
more crystals ; and if the exposure of the mother waters to
the air takes place over a very great surface, we obtain a
muriate of tin crystallized in very thin and slight scales
Baume had observed this last method of crystallizing. The
oxygenized muriatic gas is combined with the mother wa-
ters with a good deal of energy, a considerable quantity of
caloric is extricated, and after cooling, the liquor goes into

a silkv

208 On the Muriate of Tin.

a silky mass of crystals of muriate of tin. If we purify
the crystals of muriate of tin by solutions in pure water
and by crystallization they assume more consistence and
more density.

The crystallized muriate of tin is very" soluble in cold
water; the solution lakes place verv speedily,' and produces
a considerable decrease of temperature. The mean decrease
of temperature in the experiments which I made was 9° of
Reaumur, the temperature of the atmosphere and that of the
substances employed being 5Q. The mixture of the mother
waters and of pure water produces no change of temperature.
As I had observed that these mother waters became a
little fuming on being concentrated, I tried to distil both
the highly concentrated mother waters and crystallized
muriate, to see if I could not obtain a muriate of tin similar
to that which was known by the denomination of fuming
liquor of Libavius : I obtained at first a weak muriatic acid,
and afterwards the muriate passed into the receiver, where
it was sublimed into the neck of the retort in a white mass
formerly known by the name of butter of tin. With the
same view I passed muriatic acid gas as dry as possible
through the concentrated mother water of muriate of tin :
it became fuming, and gave crystals on its mixture with
pure water. JBufl ought to observe that the fuming li-
quor of Libavius exhales vapours much thicker and more
abundant, the whiter and the denser it is.

The combinations of muriatic acid and tin in the state
of solution, of crystals and of mother water, are always
effected with an excess of ,acid ; and we see from what has
been said, that all of them are susceptible of infinite varia-
tions in their state. We must not be astonished, therefore,
if the results which they produce in dyeing are so uncertain
and so different from each other. The least variable state
of muriate of tin seems to be that of very while and well-
formed crystals. It is in this state that this mordant ought
always to be employed in dyeing, by associating it with a
greater or less quantity of pure nitric acid, according to
the shade which we wish to obtain : such a composition
can alone be always uniform and give constant results.

By taking advantage of the facts contained in this me-
moir, it would he easy to describe a simple and advantageous
process for preparing on a large scale the muriate of tin in
crystals : I have nevertheless met with some very embarrass-
ing difficulties in the execution, which I have succeeded in
removing; and the full description of my labours will be
given in a subsequent memoir,

XXXVIII. The

[ 209 ]

XXXVIII. The Case of a Man who died in consequence of
the Bile of a Rattlesnake : with an Account of the Ef-
fects produced by the Poison. By Everard Home,
Esq. F.R.S*

Opportunities of tracing the symptoms produced by
the bite of' poisonous snakes, and ascertaining the local
effects on the human body when the bite proves fatal, are
of such rare occurrence, that no well described case of this
kind is to be met with in any of the records that I have
examined. I am therefore induced to lay before this So-
ciety the following account, with the view of elucidating
this subject, in which the interests of humanity are so
deeply concerned.

Thomas Soper, 26 years of age, of a spare habit, on the
17th of October 180Q, went into the room in which two
healthy rattle-snakes, brought from America in the pre-
ceding summer, were exhibited. He teased one of them
with the end of a foot rule, but could not induce the snake
to bite it, and on the rule dropping out of his hand, he
opened the door of the cage to take it out : the snake im-
mediately darted at the hand, and bit it twice in succession*
making two wounds on the back part of the first phalanx
of the thumb, and two on the side of the second joint of
the fore finger. The snake is between four and five feet
long, and when much irritated bites the object twice, which
1 believe snakes do not usually do.

The bite took place at half past two o'clock. He went
immediately to Mr. Hanbury, a chemist in the neighbour-
hood. There was at that time no swelling on the hand^
and the man was so incoherent in his language and be-
haviour, that Mr. Hanbury considered him to be in a state
of intoxication^ and gave him a dose of jalap to take off
the effects of the liquor, and made some slight application
to the bites. It appeared on inquiry, that the man had
been drinking, but that before he was bitten there was no-
thing unusual in his behaviour. After leaving Mr. Han-
bury, the hand began to swell ; which alarmed him, and he
went to St. George's hospital. He arrived there at three
o'clock. The wristband of his shirt had been unloosed,
and the swelling had extended half way up the forearm be-
fore his admission. The skin on the back of his hand was
very tense, and the part very painful. At four o'clock the

* From the Philosophical Transactions for 181Q, Part I.

Vol. 36. No. 149. Sept. 1 8 10. O swelling

310 The Case of a Man who died

swelling extended to the elbow, and at half past four it hat!
reached half way up the arm, and the pain had extended
to the axilla. At this time Mr. Brodie, who visited him in
my absence, firat saw him: he found the skin cold ; the
man's answers were incoherent: his pulse beat 100 strokes
in a minute, and he complained of sickness. Forty drops
of aqua ammonias puree, and thirty drops of spiritus setheris
vitriolici in an ounce of mistura camphorata, were given to
him, but did not remain on his stomach. The wounds
were bathed with the aqua ammonia purse, and the arm and
forearm had compresses wetted with camphorated spirits
applied to them. At five o'clock he took two drachms of
spiritus ammoniae compositus, and 30 drops of aether, in
an ounce and a half of mistura camphorata, which re-
mained on his stomach. At six o'clock his pulse was
stronger; at half past seven his pulse was very feeble, and
30 drops of aether, and the same quantity of aqua ammoniae
pure were given in water. At half past eight it was re-
peated. At nine o'clock he had the feeling of great de-
pression, his skin was cold, his pulse weak, beating 80
strokes iu a minute. The dose was increased to 50 drops
of both medicines, and repeated. At a quarter past ten
o'clock the pain had become very violent in the arm : hi*
pulse was stronger, but fits of faintness attacked him every
15 minutes, in which the pulse was not perceptible, but in
the interval his spirits were less depressed. In the course
of the evening he had two stools. At half past eleven
o'clock I first saw him. The hand, wrist, forearm, and
arm were much swelled up te> the top of the shoulder, and
into the axilla. The arm was quite cold, and no pulse
could be felt in any part, not even in the axilla, the swell-
ing preventing me from feeling the axillary artery with any
degree of accuracy. The wounds made on the thumb were
just perceptible ; those on the finger were very distinct.
His skin generally was unusually cold. I took some pains
to diminish his alarm of danger, and found his mind per-
fectly collected: he said he hoped he should recover. At
one o'clock in the morning of the 18th, he talked indi-
stinctly: his pulse beat 100 in a minute; the attacks of
faintness came on occasionally. The mediciue was re-
peated every hour.

At eight o'clock in the morning of the 18th, his pulse
beat 132 strokes in a minute, and was very feeble. The
swelling had not extended beyond the shoulder to the
neck, but there was a fulness down the side, and blood
was cxtiavasated under the skin as low as the loins, giving

the>

hi consequence of the Bite of a Rattlesnake, 21 1

the hack on the right side a mottled appearance. The
whole arm and hand was cold, but painfnl when pressed;
the skin was very tense; on the inside of the arm below
the axilla, and near the elbow, vesications had formed;
and under each of the vesications there was a red spot in
the cutis, of the size of a crown piece. The skin generally
over the body had become warm. He was low and de-
pressed ; there was a tremulous motion of his lips, and the
faintings recurred at nearly the same intervals as in the
preceding evening. The last dose of medicine was re-
jected by vomiting, but some warm wine remained on his
stomach. The arm was fomented. At twelve o'clock, in
addition to the above symptoms, there was a starting of his
limbs. He had attempted to take some broth, but his
stomach did not retain it. The skin of the whole arm had
a livid appearance, similar to what is met with in a dead
body, when putrefaction has begun to take place, unlikfc
any thing which I had ever seen in so large a portion of the
living body. An obscure fluctuation was felt under the
skin of the outside of the wrist and forearm, which induced
me to make a puncture with a lancet, but only a small
portion of a serous fluid was discharged. My colleague,
Dr. Nevinson, was present at this visit, and we agreed to
continue the internal use of the volatile alkali, with the
view of rousing the stomach to action, not considering it as
having any specific power over the poison. • At eleven
o'clock in the evening, finding that his stomach did not
always retain the medicines, nor even small quantities of
brandy, which we're given him, I directed the volatile alkali
to be left off, and two grains of opium to be given, and
repeated every four hours. At this time his pulse was
scarcely perceptible at the wrist, the fainting fits were not
less frequent. The vesications and red spots were increased
in size.

October 19. At nine o'clock in the morning his pulse
was scarcely perceptible: his extremities were cold; the
vesications were larger, and the size of the arm was dimi-
nished. He was drowsy, probably from the effect of the
opium. He had taken nothing but brandy during the
night. At three o'clock in the afternoon he was more
depressed : spoke only in whispers : the vesications were
increased: the fainting fits less frequent. The aim wa$.
diminished in size, and he had sensation in it down to the
fingers. At eleven o'clock at night his pulse beat 130 in a
minute, and was low. The opium was left off. A stool
was procured by clyster. He was ordered to have a glass

0 2 of

JU The Case of a Man who died

of camphoaated mixture occasionally, and wine and brandy
as often as he could be induced to take them.

October 20. He had dozed at intervals during the night;
his spirits were better, and his extremities warmer. At
nine o'clock he took coffee for breakfast. He afterwards
took some fish for dinner, but it did not remain on his
stomach ; he therefore took brandy and coffee at intervals,
half an ounce at a time, as larger quantities did not remain
on his stomach.

October 21. He had slept at intervals during the night,
but was occasionally delirious : his pulse 120 in a minute.
Brandy and jelly were the only things that stayed on his
stomach. The size of the arm was reduced, but the skin
was extremely tender.

October 22. He had slept during the greatest part of
the night : his pulse beat <JS in a minute : he took some
veal for dinner, and brandy at intervals. In the evening
his pulse became full and strong : he was ordered wine in-
stead of brandy. The right side of the back down to the
loins was inflamed and painful ; and had a very mottled
appearance, from the extravasated blood under the skin.

October 23. His pulse continued full, and the arm was
very painful, though reduced in size. The vesications had
burst, and the exposed cutis was dressed with white oint-
ment. Stools were procured by an opening medicine. He
took some veal and porter for dinner; the wine was left
off. In the evening he had a saline draught with anti-
monial wine.

October 24. There was no material change.

October 25. His pulse had increased in frequency, but
fn other respects he was nearly the same. His bowels were
opened by medicine.

October 26. The arm was more swelled and inflamed.

October 27. The inflammation of the arm had in-
creased : his tongue was furred, and his pulse was very fre-
quent. He attempted to sit up, but the weight of the arm
and the pain prevented him. The arm was bathed with
spirits of wine and aqua ammonia acetata; in equal quan-
tities.

October 28. A slough had begun to separate from the
inside of the arm below the axilla, and a purging had come
on, for which he was ordered chalk mixture and laudanum.
In the night he had a rigor.

October 29. The purging had abated ; his pulse beat
100 in a minute, and was feeble. A large abscess had
formed on the outside of the elbow, which was opened,

and

in consequence of the Bite of a Rattle-snake. 213

and half a pint of reddish brown matter was discharged
with sloughs of cellular membrane floating in it. The
lower part 'of the arm became much smaller, but the upper
part continued tense. A poultice was applied to the
wound. The lower portion of the arm and the forearm
were covered with circular stripes of soap cerate. He was
ordered to take the bark, and allowed wine and porter.

October 30. The redness and swelling of the upper part
of the arm had subsided : the pulse was 100 in a minute.
The purging had returned. The bark was left off: the
chalk mixture and laudanum were given, and an opiate
clyster administered.

October 31. The pulse beat 120 in a minute. The
discharge from the abscess had diminished, the purging
continued, and at night he had a rigor.

November 1. The pulse was 1 20. His voice was feeble ;
he had no appetite; was delirious at intervals. Ulceration
had taken place on the opening of the abscess, so that it
was much increased in size. He drank two pints of porter
in the course of the day.

November 2. His pulse was very weak ; his countenance
was depressed ; his tongue brown ; the ulceration had spread
to the extent of two or three inches. Mortification had
taken place in the 6kin nearer the axilla. His stomach re-
jected every thing but porter: in the night he was de-
lirious.

November 3. The mortification had spread consider-
ably ; the purging continued : the forefinger, which had
mortified, was removed at the second joint,

November 4, He died at half past four o'clock in the
afternoon.

Sixteen hours after death, the body was examined by
Mr. Brodie and myself, in the presence of Mr. Maynard,
the house surgeon, and several of the pupils of the hospital.

With the exception of the right arm which had been
bitten, the body had the natural appearance. The skin was
clear and white; and the muscles contracted.

The wounds made by the fangs at the base of the thumb
were healed, but the puncture made by the lancet at the
back of the wrist, was still open. That part of the back
of the hand, which immediately surrounded the wounds
made by the fangs, for the extent of an inch and a half in
every direction, as also the whole of the palm, was in a
natural state, except that there was a small quantity of ex-
travasated blood in the cellular membrane. The orifice of
the abscess was enlarged, so as to form a sore on the outside

0 3 Ot

214 The Case of a Man who died

of the arm, elbow, and forearm, near six inches in length.
Around this, the skin was in a state of mortification, more
than half way up the outside of the arm, and as far down-
wards, on the outside of the forearm. The skin still ad-
hered to the biceps flexor muscle in the arm, and flexor
muscles in the forearm, by a dark-coloured cellular mem-
brane. Every where else in the arm and forearm, from the
axilla downwards, the skin was separated from the muscles,
and between these parts there was a dark-coloured fluid,
with an offensive smell, and sloughs of cellular membrane
resembling wet tow, floating in it. The muscles had their'
natural appearance every where, except on the surface,,
which was next the abscess. Beyond the limits of the
abscess, blood was extiava«ated in the cellular membrane,
and this appearance was observable on the right side of the
hack as far as the loins, and on the right side of the chest
over the serratus major amicus muscle.

In the thorax the lungs had their natural appearance.
The exterior part of the loose fold of the pericardium, where
it is exposed, on elevating the sternum was dry, resembling
a dried bladder. The cavity of the pericardium contained
half an ounce of serous fluid, which had a frothy appear-
ance, from an admixture of bubbles of air. On cutting
into the aorta, a small quantity of blood escaped, which
had a similar appearance. The cavities of the heart con^
tained coagulated blood.

Jn the abdomen, the cardiac portion of the stomach was
moderately distended with fluid : the pyloric portion was
much contracted; the internal membrane had its vessels
very turgid with blood. The intestines and liver had a
healthy appearance. The gall bladder was moderately full
of healthy bde. The lacteal? and the thoracic duct were
empty; they had a natural appearance.

In the cranium the vessels of the- pia mater and brain
were tunrid with blood ; the ventricles contained rather
more water than is usual, and water was effused into the
cells connecting the pia mater and tunica araehnoides. It
is to be observed, that these appearances in the brain and
its membranes are very frequently found in cases of "acute
diseases, which terminate fataliy.

The following cases were sent from India, to my late
friend Dr. Patrick Russell: thev arrived after his deaths
and Mr. Claude Russell very kindly gave them to me,
knowing the subject of them to be one in which I had
taken an interest. As they correspond in many of the
circumstances with that which has been detailed, I have

inserted

in consequence of the Bite of a Rattle-snake. ^15

inserted them in this place, as well as an experiment which
1 had an opportunity of making in the West Indies, on the
effects or the snake's poison on animals.

A boy, a slave of a gentlemen in India, was bitten by a
snake called Kamnlee by the natives, in the lower part of
the arm, at eight o'clock in the evening. The blood ilowed
very freely for some time. He died next day at noon in
great pain.

A sepoy, €0 years of age, was admitted into the hospital
of his regiment, under the care of Mr. Perrin, assistant
strhjeon, at lour o'clock in the afternoon of the 15th of
Oc.ober, 1802, in consequence of his being bitten by a
cobra di capello on the back part of the hand. At the
time of his admission he complained of pain running up
the arm. He immediately took a drachm of eaw de luce,
and this dose was repeated every half hour, and the same
remedy was applied externally as a lotion to the arm and
forearm. At four o'clock in the morning of the 16th of
October, the pain be^an to increase, and the arm to swell
with great hardness and stiffness, and tumour in the axilla^
with much inclination to vomit. He took twelve grains
of Dr. James's powder, which brought up a great quantity
of bilious matter. He drank copiously of warm water, but
no perspiration was induced. He appeared relieved for a
short lime. At eight o'clock in the morning the arm was
distended, painful, and discoloured. He took four ounces
of brandy, and repeated it every hour until twelve o'clock,
with a drachm of eau de luce occasionally. At this time
he was a little revived. The brandy was reduced to two
ounces, which were carefully and regularly given every
hour, until twelve at noon on the 17th of October, when
the arm was more free from pain, but much swelled, hard,
and black : his spirits and pulse also were considerably re-
lieved. The eau de luce was now omitted, but the brandy
was continued every hour, until twelve o'clock at noon on
the 18th of October, when the stiffness and tumor in the
axilla had disappeared ; the arm was still swelled, but was
softer, and less painful. The brandy was omitted: at
night he took six grains of Dr. James's powder. On the
lyth of October the arm was less, softer, with little or no
pain ; a blister was formed and burst on the back of the
hand, which discharged three ounces of black foetid pus.
On the 20th, an abscess burst on the hand, in the same
situation as the blister, which discharged a large quantity
of a fluid having an offensive smell. lie was directed to

O 4 take

216 The Case of a Man who died

take a drachm of Peruvian bark in port wine, every two
hours. On the 22d the swelling was gone, hut the dis-
charge was considerable. From this time the man gradually
but slowly recovered, with the loss of the use of his fore-
finger, which remained permanently extended, and some of
the other fingers were affected in a less degree.

In this case, the swelling of the arm was slower in
coming on, and less extensive; the pain running up to the
axilla, which preceded it, was mistaken for the effect of
absorption.

In the year 1782, while in the island of St. Lucia, I made
the following experiment :

A spotted dark-coloured snake, about two feet in length,
having the poison fangs on each side double, with the cor-
responding surfaces grooved, so as to form a canal for the
poison, was put into a square tin box, open at the top, in
which a half-grown rat was confined, The rat expressed*
great terror, and remained crouching in one corner of the
box, with its eyes fixed on the snake, who lay coiled up at
some distance, they were allowed to remain a few minutes
in this situation: I then raised one end of the box, which
caused the snake to slide along the smooth surface, till it
came in contact with the rat, which it immediately bit.
The rat died in a minute after the bite. I removed it im?
mediately from the box by means of a pair of long forceps.
The wounds made by the fangs were marked by two specks
of blood immediately below the shoulder blade. On di-
viding the skin with a scalpel, the cellular membrane under
it was found entirely destroyed : the muscles were detached
from the ribs, and from a small portion of the scapula.
The parts immediately surrounding the bite were exceed-
ingly inflamed; as far as I could trust to memory, the ap-
pearances very much resembled* those produced on the
muscles of a dog's thigh, by the application of white
arsenic, in consequence of which, death ensued in about
sixteen hours.

Fifteen hours after the death of the first, a second rat.
was bitten by the same snake. This rat was much irritated,
and bit the snake in the neck, so violently, that the latter
died in about ten minutes. The rat con turned, very lively
for about six hours, and then, died. On examination after
death, the bite was found to have been inflicted on the left
side of the navel, and the abdominal museles at that part
were in the same state as in the other rat, but in a less der
gree.

ft

hi consequence of the Bite of a Rattle-snake. 21 7

It appears from the facts which have been stated, that
the effects of the bite of a snake vary according to the in-
tensity of the poison.

When the poison is very active, the local irritation is so
sudden and so violent, and its effects on the general system
are so great, that death soon takes place. When the body
is afterwards inspected, the only alteration of structure met
with, is in the parts close to the bite, where the cellular
membrane is completely destroyed, and the neighbouring
muscles very considerably inflamed. *

When the poison is less intense, the shock to the general
system does not prove fatal. It brings on a slight degree
of delirium, and the pain in the part bitten is very severe;
in about half an hour, swelling takes place from an effu-
sion of serum in the cellular membrane, which continues
to increase with greater or less rapidity for about twelve
hours, extending during that period into the neighbourhood
of the bite ; the blood ceases to flow in the smaller vessels
of the swoln parts ; the skin over them becomes quite cold,
the action of the heart is so weak, that the pulse is scarcely-
perceptible, and the stomach is so irritable, that nothing
is retained in it. In about (50 hours these symptoms go
off, inflammation and suppuration take place in the injured
parts, and when the abscess formed is very great, it proves
fatal. When the bite has been in the finger, that part has
immediately mortified. When death has taken place under
such circumstances, the absorbent vessels and their glands
have undergone no chance similar to the effect of morbid
poisons, flor has any part lost its natural appearance, ex-
cept those immediately connected with the abscess.

In those patients who recover with difficulty from the
bite, the symptoms produced by it go off more readily, and
more completely, than those produced by a morbid poison
which has been received into the system.

The violent effects which the poison produces on the part
bitten, and on the general system, and the shortness of their
duration, where they o*o not terminate fatally, has frequently
induced the belief, that the recovery depended on the me-
dicines employed ; and 10 the East Indies eau de luce is
considered as a specific for the cure of the bite of the cobra
fii capello.

There does not appear to be any foundation for such an
opinion; for, when the poison is so intense as to give a
sufficient shock to the constitution, death immediately takes
place, and where the poison produces a local injury of suf-
ficient

218 On extracting liquid Sugar

ficient extent, the patient also dies, while all slighter cases
recover.

The effect of the poison on the constitution is so imme-r
diate, and the irritability of the stomach is so great, that
there is no opportunity of exhibiting medicines till it has
fairly taken place, and then there is little chance of beneficial
effects being produced.

The only rational local treatment to prevent the secon-
dary mischief, is making ligatures above the tumefied part,
to compress the* cellular membrane, and set bounds to the
swelling, which only spreads in the loose parts under the
skin ; and scarifying freely the parts already swoln, that the
effused serum may escape, and the matter be discharged as
soon as it is formed. Ligatures are employed in America,
but with a different view, namely, to prevent the poison
being absorbed into the system.

JXXXIX. On extracting liquid Sugar from Ajjplcs and

Pears.

JL he high price of sugar in France, occasioned by circum-
stances connected with the war, has induced the French
chemists to endeavour to discover processes by which sac-
charine substitutes may be extracted from vegetable sub-
stances produced in the Old World. On this subject M. Du-
buc has lately published in the jinnalrs de Ckimie various
experiments on extracting sugar from apples and pears. As
these were chiefly for the purpose of ascertaining the quan-
tity produred by different varieties of apples and pears pro-
duced in France, it will be quite sufficient for the English
reader to state ihe process and the general result.

Boil eight quarts of the juice of ripe apples in a brass
pan for about a quarter of an hour, and then, for the pur-
pose of neutralizing the acid of the fruit, add, in four sepa-
rate portions, about two minutes after each other, ten
drachms of finely pounded chalk. The chalk occasions an
effervescence in the juice, by the escape of the carbonic acid
from the chalk in the form of gas. The boiling is to be con-
tinued for eight or ten minutes longer, and the mixture to
be kept stirred, to multiply the points of contact between the
ju'cc and the chalk.

The whites of three eggs beat up in three glasses of cold
water are then to be added at once to the mixture, and well
jstirred into it for the purpose of clarifying the syrup. Let

it

from Apples and Pears. 210

h still boil for a quarter of an hour. The white of the eggs,
coagulating by the boiling, entangles the impurities of the
juice, which is then to be strained through a flannel strainer
supported at the four corners.

When about half-cooled strain it again, that it may be
well clarified.

By these operations the juice loses about one-third of its
weight. What remains is to be reduced to about one-half
of its bulk bv boiling ; after which the heat must be lower-
ed ; but the evaporation must be continued below the boil-
ing point, until the syrup be so concentrated, that on cool-
ing it may be of the consistence of common treacle.

Those who are acquainted with chemical processes will
know, when it is sufficiently concentrated by observing the
pellicle formed on its surface. A vessel capable of contain-
ing a quart, or two pounds of water, will contain 2lb. 10 oz.
of svrup or liquid sugar.

This liquid sugar is represented as savoury, fresh, and
capable of sweetening water very well, or even milk without
curdling it.

In one of M. Dubuc's experiments the juice had a milky
look, even after the white or egfts was added. To remedy
this, h< employed twelve drachms of powdered charcoal,
and stirred and boiled the mixture for about ten minutes ;
alter which he strained it once through a conical bag, and
wh«m nearly cold passed it through the filter a second time,
the sediment of the first filtration being left to make the filter
the closer.

The success of this experiment induced him to try to ob-
tain the clarified liquid sugar by using chalk and charcoal
only, without employing white of eggs. To six quarts of
apple juice boiled for a quarter of an hour, he added, at four
separate times; two minutes from each other, a mixture of
seven drachms of chalk, and one drachm of small coal in
fine powder. The boiling was continued till the liquid was
reduced one half: when half cooled it was passed through
flannel, as directed above, and when nearly cold was strained
a second time, and lastly it was evaporated with the above-
mentioned precautions.

The process for extracting the saccharine matter from
pears diners not at all from the above ; but more chalk seems
to be required to saturate and separate the acid.

If the fruit be suffered to lie bruised for about 24 hours
before expressing the juice, the produce of sugar will be
greater, — this process contributing in some way or other
fo the development of the saccharine principle.

When

220 On Musical Time,

When the boiling heat is too long continued, the colour
of the syrup becomes darker. Does not this serve to sug-
gest that the process might be improved by employing a wa-
ter bath, instead of applying the heat directly to the boiler
or kettle ?

XL. On Musical Time*
To Mr. Tilloch.

Sir, It has long been a matter of just complaint among
musicians, that no method has yet been invented to regulate
musical time. The terms Largo, Adagio, Andante, Presto,
&c. seem to be mere terms of expression, and not the de-
finite characters of time; for it is absurd to suppose that
these terms mean any portion of time whatever, so that the
performer is left entirely to use his own taste and judgement.
To remove this imperfection, Loulie, a French musician, in^
vented an instrument called The Musical Chronometer, for
the purpose of measuring time by means of a pendulum.

But this instrument, though it appears perfect in theory,
could never be brought into practice, either from the trouble
of adjusting it at the beginning of every movement, or the
difficulty which the performer experienced in conforming to
mechanical rules.

Another chronometer of a more simple construction hag
$ince been invented, consisting of a tape graduated into feet
and inches, with a plummet affixed to it. The way of using
this instrument is to prefix one of the notes to each move-
ment, and also the length of the pendulum, which vibrates
once during its performance. But surely this method must
be attended with as much uncertainty as to find the time
that a person would be in walking a mile, by finding what
time it would take him to walk a yard.

Although these modes of introducing chronometers have
hitherto failed, yet I am inclined to believe, that, by a proper
use of timerkeepers, it will be very easy for the present and
future composers to fix the time to their music, so as not to
be misunderstood even by a young performer. This may be
done very correctly without any other instrument than a
pocket- watch which shows minutes and seconds : Thus,

Let the composer take notice of the number of minutes
and seconds that elapse during the performance of' any
movement, according to the time in which he intends it
should be played or sung, and let these numbers be written
at the beginning of it. The words Largo, Adagio, An-
dante,

Analysis of Socotrine and Hepatic Aloes. 221

dante, Presto, &c. should still be used as terms of ex-
pression,— not as the definite characters of time.

Suppose, for example, that a piece consists of three move-
ments : — the first is performed id to', 40" ; the second in
(i\ 30"; and the third in 8', 10". These figures being
written at the beginning of each respectively, will convey an
exact idea of the author's time to all future performers. And
thus a check may be put upon the licentiousness of the
fiddle-slick ; for some performers are so rapid in their move-
ments, as to neglect both taste and expression. This rapid
mode of playing seems to be a growing evil ; for it has been
said by good judges of the subject, that Handel's music
was performed much slower a century ago, than it is in our
best concerts at this time.

St. Austin Street,
Sept. 23, 1810. W.

XLT. Comparative Analysis of Socotrine and Hepatic Aloes .
By M. Tromsdorff. Extracted by M. Vogel*.

Jljesides the two kind of aloes known by the name of
socotrine and hepatic, there are two others, one of which,
lucid aloes, is extremely rare, and the other, cahalline aloes,
is so inferior, and so variable in its qualities, that M. Troms-
dorff did not think it worth alluding to in his inquiries.

After having spoken of the natural history and of the ex-
traction of the juice of the plant, an analysis of the two
kinds is given, and it is this part of his worjc that we pro-
ceed to notice.

Experiments on Socotrine Aloes.

Action of tvater. a.) Four ounces of socotrine aloes
pounded, were boiled with three pounds of distilled water
in a silver vessel. The aloes, being entirely dissolved, pre-
sented a transparent liquid of a deep yellow; but, when al-
lowed to cool, a yellow powder was precipitated. When
the liquor was quite cold it was decanted and filtered, and
a brown transparent mass remained at the bottom of the
vessel.

After desiccation, this substance weighed one ounce, and
exhibited the following character : —

1. ft was transparent, of a brownish yellow, very brittle,
and of a titter taste.

2. It melted at a gentle heat.

* Aivialcs de Chimir, tome lxviii. p. 11.

3. It

2£2 Comparative Analysis of

. 3. It was insoluble in water, but very soluble in alcohol
and in liquid potash.

4. When a lighted candle was applied to it, it burned
with a brisk flame.

l'Voin the above it is evident that this substance was the
resinous part of the aloes. It is also very remarkable, that
this great quantity of resin, joined to the other parts of the
aloes, is easily soluble in warm water; but it is separated
from it on cooling.

b.) The aqueous solution, which contained three ounces
of dissolved parts, acted in the following manner: —

1. It was perfectly transparent, or' a golden ye' low colour :
when placed in contact with the air, it became of a brown
colour, but without being turbid.

2. It reddened turnsole paper.

3. The alkalis and the alkaline carbonates deprived it
of the property of reddening the blue colours, but these
solutions produced no other changes in it.

4. Some drops of muriate of iron at the maximum pro-
duced a black colour.

5. The nitrates of silver and of lead disturbed it slightly j
nitric acid restored its transparency to the liquor.

6. The sulphuric, nitric, and muriatic acids precipitated
from it a small quantity of a yellow powder, which acted
like a resin, and which did not exceed 0-02.

7. A solution of animal gelatine experienced no change
in it.

c.) The aqueous solution was evaporated to dryness in
the sand-bath : there remained a mass similar to aloes, and
of a bitter taste. It was completely dissolved in hot or
cold alcohol.

Ether which was digested with part of this powder was
not coloured with it, and did not dissolve a single atom of
it.

These properties induced the author to take that part of
the aloes for the principle which M. Hermstadt designated
by the name of saponaceous principle, or soap of plants ; the
essential character of which is solubility in water and in
alcohol, but insolubility in ether.

This saponaceous principle is found in several vegetables,
as in saffron, rhubarb, &c. : it is nevertheless probable that
there are different species of a more or less bitter taste.

Action of Alcohol, a.) Four ounces of aloes were di-
gested with 16 ounces of alcohol. The solution was com-
plete, and there only remained on the filter 12 grains of lig-
neous matter which was contained in the aloes.

b.) The

Socotrine and Hepatic Aloes, 223

b.) The alcoholic liquor was of a deep yellowish red.
When mixed with its weight of water, it was introduced
into a retort, and the alcohol was distilled from it.

After cooling, the liquor was not turbid : it was then eva-
porated to dryness, and the dry mass being redissolved in
boiling water, precipitated, after rooling, resin, which when
dry weighed an ounce. This experiment in other respects
only confirmed the proportion of resin found after the treat-
ment with water.

Experiments on Hepatic Aloes.

Action of Water. — Sixteen ounces of hepatic aloes were
subjected to the same experiments with socotrine aloes.
The aqueous solution left, upon cooling, three ounces of
resin, the water having dissolved 13 ounces of matter.

The solution was also acid, and blackened the muriate of
iron at the maximum ; it was slightly disturbed by the
nitrates of silver and of lead.

When evaporated to dryness, there remained a mass very
soluble in hot and cold water, without affording any resinous
sediment.

Alcohol dissolves it also, but ether has no action on it.

b.) The three ounces of resinous precipitate being dis-
solved in alcohol, there remained a residue weighing two
ounces insoluble in this menstruum. We shall speak of
this presently.

c.) The alcoholic liquor, when evaporated to dryitess, left
a resinous mass, which had the following properties :

1. Insolubility in warm or cold water.

2. Great solubility in alcohol, in ether, and in a solution
of caustic potash.

3. It melted easily at a gentle heat, and was soon car-
bonized.

4. Great inflammability, burning with a brisk flame.

d.) The two ounces of residue (b), insoluble in alcohol
and in ether, were divided into three parts, and treated as
follows :

1 . Distilled in a retort, there passed into the receiver, a
fetid oil, with an ammoniacal liquor, and a great quantity
of charcoal remained.

2. The concentrated or the diluted acetic aeid had no
action on it.

3. A boiling solution of caustic potash dissolved the
substance entirely. The liquor was not disturbed by an ad-
dition of water, but the acids precipitated from it a brown
spongy mass, which was somewhat elastic.

This-

224 Analysis of Aloes,

This precipitate when collected -and distilled in a retort
yielded an ammoniacal liquor, from which it should seem
that the substance in question is nothing more than a coa-
gulated vegetable albumen.

Action of Alcohol, — Four ounces of hepatic aloes were dis-
solved in alcohol : there remained an insoluble mass, weigh-
ing 4-3- drachms, which was albumen.

The alcoholic solution was evaporated to dryness, and the
residue was boiled with water. It was entirely dissolved ;
but upon cooling the resin separated from it. By this
means we obtained three ounces of saponaceous principle,
and 2\ drachms of resin.

From all the above experiments the author has drawn the
following consequences :

1. Socotrine aloes are completely dissolved in boiling wa-
ter. The resinous part is separated from it by cooling.

2. It is also dissolved in alcohol without leaving any re-
sidue.

3. The parts which are soluble in water contain more
bitter principle than those which are soluble in alcohol, al-
though these last are not entirely free from it.

4. The hepatic aloes differ from the socotrine, in so far
as they contain an albuminous vegetable matter, and less
resin than the latter.

5. It is not completely dissolved in boiling water, for the
coagulated albumen resists it.

6. It is not wholly dissolved in alcohol. This is the way
in which we may distinguish it very evidently from socotrine
aloes, even when their physical characters are the same.

\ ' ! ~

XLII. Analysis of Aloes, By M. Bracoknot*.

§ T. Aloes are procured from several plants which bear
the same name : at Morviedris in Spain the aloe vulgaris
furnishes three sorts, which only differ from each other in
the way in which they arc prepared. In the West Indies
the substance in question is extracted from the aloe barba-
densis, which, as well as the foregoing species, is regarded by
some writers as a variety of the aloe peifuliatd, and which
is cultivated in the most wretched soils. The aloe spi cat ac
a distinct species from the above, also furnishes juice of a
good quality; but the purest and most valuable is brought
in bladders from the island of Socotra, situated at the en-
trance of the Arabian Gulph in the Indian Seas: it is ob-

* A finales de Chimie, tome Ixviii. p. SO*

t tained

Analysis of Aloes. 225

tained by cutting transversely tbe leaves of the aloe perfo-
liata socotrina, placing earthen vessels underneath it to
receive the juice, which is thickened in the sun.

The aloes which was made the subject of the examina-
tion is of a yellowish red, and semi-transparent : it pre-
sents, in its fracture, several yellow points which glister on
a red ground : reduced to powder it is a fine yellow colour :
it has a very bitter taste, and a smell which some persons
think is not disagreeable: it does not become electrical on
friction.

• When exposed to a heat of 80° + 0 of Reaumur, it be-
gins to soften, and then melts : on account of its being
easy of fusion, it is much easier to pulverize it in winter
than in summer. If we present a piece of it to the flame
of a candle, it melts with a crackling noise, and inflames.

§ II. 50 grammes of aloes were distilled at a heat very
gentle at first, and incapable of decomposing it, when the
following products were obtained : 1st. Eight grammes of
water charged with an essential oil which gives aloes their
smell. 2d. At a greater heat there passed over 8*7 gram-
mes of almost colourless water, in which I found one gram-
me of acetic acid, but no ammonia, on adding quicklime
in powder to the liquor. 3d. Five grammes of a heavy red
oil soluble in alcohol. 4th. A great quantity of oleaginous
hydrogen gas and carbonic acid. 5th. There remained in
the retort (which had begun to melt) twenty grammes of a
hard charcoal very voluminous and honeycombed, which
retained a great quantity of hydrogen, which we saw burnt
by exposing it a long time in a crucible at a strong heat in
order to incinerate it, which was impossible : it preserved all
its blackness, its shining appearance, and a great hardness :
it had lost however 12*5, which I attribute in a great mea-
sure to the hydrogen. The 7*5 grammes which remained
did not contain any potash. This charcoal was treated
with muriatic acid : the filtered liquor was precipitated by
ammonia, which separated oxide of iron and a small quan-
tity of phosphate or lime : the carbonate of potash preci-
pitated some decigrammes of carbonate of lime.

If we heat nitric acid on this charcoal, we obtain a small
quantity of tanning matter which precipitates strong glue.

§111. Aloes in powder, bruised in a glass mortar witli cold
water, yielded a mass which, squeezed through the hands,
was tacky like turpentine. We succeeded in obtaining
a complete solution by adding water in successive quanti-
ties, but it required a great quantity ; the last portion which
remained to dissolve was similar to the first in point of

Vol. 36. No. 149. Sept. 1810. P bitterness

226 Analysis of Aloes,

bitterness and its other properties : this solution becatfrtj
frothy on being shaken.

One hundred and forty-eight grammes of water at 3'&°-\- &
of Reaumur were sufficient entirely to dissolve four grammes
of aloes, with the exception of one decigramme of an im-
pure ligneous matter : the liquor became turbid as it cooled,
and deposited part of the matter dissolved. This solubility
of aloes in water increases in such a manner, in consequence
of heat, that we may obtain a syrupy solution, which then
ceases to deposit any sediment.

When tried by the re- agents, the solution of aloes in
water presented the following effects :

1. It reddened turnsole tincture in a very marked man-
Tier.

2. The alkalis and lime water render the colour darker^
without precipitating any thing from it.

3. The sulphate of iron produces a brown colour, and a
precipitate of the same colour soOn afterwards.

4. The decoction of gall nuts forms a flaky yellowish
precipitate. The supernatant liquor is much less bitter, and
weaker in colour.

5. The subacetatje of lead also produces a precipitate in
this liquor. The supernatant liquor becomes almost co-
lourless.

6. The nitrate of copper and of lead and muriate of tin
produce slight sediments in it, but which do not appear to
me to be true chemical combinations; for solutions of
muriate of soda and of the other neutral salts produce quite
as much. These saline matters therefore acton the solution
of aloes in the same manner as upon that of tannin in
water, bv weakening the action of this fluid on the not
very soluble matter which is dissolved in it.

The above solution of aloes, which was of a fine golden
colour, was put into three bottles : the first, which held a
pint, was entirely filled with it and well corked : the second,
which was* of the same capacity, was half rilled and left
open : the third, being a medicine phial, was one quarter
filled. In two months and a half the following phaenomena
were observed : The liquor of the first bottle had preserved
its colour without alteration; that of the second was a very
dark red, and was discoloured by the oxygenized muriatic
acid, which produced a flaky precipitate. Jn the third a
quantity of mucus was formed. The coloured liquor of
these two last bottles had acquired a kind of viscositv. It
would seem, in fact, that there is a substance produced ana-
logous to gelatine; for the decoction of gall nuts formed in

it

Analysis of Atoms', 22 f

it a precipitate very abundant in comparison of that which
is produced in the recent solution of aloes.

These facts, in my opinion, amply prove that aloes does
hot constitute a species of the resins.

§ IV. Alcohol at 38° entirely dissolves aloes very speed-
ily, particularly if heat be employed; which announces the
absence of gummy or extractive matter in this substance.
The filtered liquor was of such a deep red colour that its
transparency could scarcely be perceived : water produces an
abundant sediment in it of a pale vellow colour, owing to
this liquid which is retained in it, for it resumes its primi-
tive brown colour on desiccation.

If we evaporate the alcoholic solution of aloes, we re-
mark that the least motion* the slightest breathing on the
liquid, produces a kind of crystallization in it, which dis-
appears and then is reproduced. Although alcohol dissolves
this substance very well, this is not the case with the fixed
and volatile oils. I exposed to heat a mixture of oil of olives
and aloes, and this last substance remained in a melted state
at the bottom : the essence of turpentine, which I boiled with
the aloes, acted nearly in the same manner: the volatile
oil nevertheless assumed a slight amber colour.

§ V. Alkaline solutions dissolve aloes cold and with
much facility: combinations are formed in which the bit-
terness seems in some measure marked. Acids produce
in these solutions abundant precipitates which are coloured
on desiccation. The volatile alkali diluted in water, also
dissolves aloes perfectly : after having filtered the liquor, it
was of a deep red colour : and it was evaporated slowly, to
drive off the excess of ammonia. In proportion as this liquor
was thickened the surface exhibited a continual motion,
which seemed to indicate a tendency to crystallization ; for
we remarked other needles which successively appeared and
disappeared. On continuing the evaporation almost, to
dryness, we obtained crystals in needles attached to a resi-
nous-like mass : on heating this matter with a ce'rtain quan-
tity of lime and water, a very evident extrication of am-
monia takes place.

§ VIvThe weak acids have not a very remarkable action
upon aloes : nevertheless they dissolve it better than water,
which whitens the solution of aloes in distilled vinegar.
The mineral acids act much more energetically upon it.
NitTic acid dissolves it very well when cold, and there re-
sults a deep red liquor, from which water throws down an
abundant precipitate.

Ten grammes of aloes were treated in a retort with eighty

P 2 gramme*

its Analysis of Aloes,

gramme? of nitric acid at 36°, taking care to administer the
fire with caution. There was a brisk re-action, and libera-
tion of abundant red vapours. When they disappeared, the
retort was removed from the fire, and the liquor which it
contained was of a deep yellow colour. It deposited upon
cooling a great quantity of a flaky yellow substance. The li-
quor, when evaporated to the consistence of honey, was di-
luted in water and filtered. There remained in the filter a
vellow substance, which, after having been washed and dried,
formed one fourth of the aloes employed in the experiment.
I thought at first that this matter was a portion of the aloes
which had escaped the action of the nitric acid : but the fol-
lowing properties soon convinced me that it was an acid
with some analogy to the yellow acid, and the detonating
matter which Messrs. Fourcroy and Vauquelin obtained by
the action of the nitric acid on animal substances, but
which differs from it in several respects.

The yellow aloetic acid, when well washed and dried, is of
a very fine yellow colour, and extremely bitter. It does not
crystallize, reddens blue turnsole paper, and effervesces
with the alkaline carbonates. ,

It has an agreeable aromatic smell, particularly when it is
gently heated. It melts like nitre, gives out an aromatic
vapour mixed with bitterness, and leaves an abundant charry
residue.

When distilled at a gentle heat, it furnished all the usual
products of vegetable substances, and ended by detonating,
producing at the same time a purple flame. A very abun-
dant charcoal remained, forming the third part of the sub-
stance employed.

This acid is not very soluble in water. It required two
hectogrammes and a half of this fluid at 10°-|-0 Reaumur to
dissolve entirely two decigrammes of it. This solution was
of the fine red colour of arterial blood. The muriate of tin
produced in it a precipitate of the colour of wine-lees, and
the sulphate of iron heightens the colour.

Fifteen grammes of alcohol at 38° could only dissolve a
decigramme of this yellow acid, and the solution was of a
verv dvcp red colour.

The mineral acids, warm, dissolve this yellow matter with-
out extricating any thing from it ; but it is soon deposited
afterwards on account of its insolubility.

Potash forms with it a combination capable of crystal-
lizing, and of a deep-red. This red salt detonates with the
violence of gunpowder, either on exposing it to a certain
heat, or by touching it with a lighted coal, aod leaves after

its

Analysis of Aloes. 229

its combustion a slight charry trace, and a remarkable smell
of prussic acid, which might lead us to suspect the presence
of azote.

, We may easily produce this red detonating substance, by
pouring on the yellow acid of aloes a slight warm solution
of caustic potash, which has but a weak dissolving action
upon it.

The nitric liquor, from which the yellow aloelic acid has
been separated, was saturated by potash. A very small
quantity oF red detonating matter was deposited at the end
of four-and-twenty hours. Nitrate of lime, which was
poured upon it, produced an abundant precipitate of oxalate
of lime: when well washed and dried it weighed 3-*- grammes.
The liquor separated from the oxalate of lime was precipi-
tated by the nitrate of lead. The sediment, when treated
with one third of its weight of weak sulphuric acid, fur*
nished about one gramme of malic acid, partly dried.

§ VII. It results from the above facts, that aloes is not
a gum resin as has been thought, since we do not find in it
either the one or the other of these associated principles :
nor can we class aloes among the resins, although it resem-
bles them much more than the gums. It is therefore a
principle std 'generis, which I propose, from its properties,
to call resino amer. This principle is probably widely diffused,
and has its species like other vegetable substances. It is this
which had been at first confounded with the resins, which
have been sometimes taken for oxygenated extractive matter,
and which M. Vauquelin has amply described in his interest-
ing memoir upon different species of quinquina. It is also
the same substance which is deposited more or less abun-
dantly from the decoctions of many of the bitter plants, in
which febrifuge virtues have been for a long time recog-
nised ; such as the artemisia alsyvt hium , the centauria cal-
citrapa and benedtcta^ chicory and fumitory *.

It is true that the virtues of these plants have been
reckoned less efficacious than the astringent febrifuges : and
I am persuaded that in kina, the principle which acts spe-
cifically against the fever, and the periodical return of dis-
eases, is owing to the combination oi the resino amer with
tannin, or some similar substance. My colleague, Dr. Hal-
dats, directed by these views, is about to enter upon some
important experiments, of which he will give an account,

* It appears to me that the resiniform matter found in the bile by M. The-
jurd greatly resembles the rcsinu-amer of aloes.

P 3 and

230 Fatal Case of Inguinal Hernia*

and which may perhaps lead to some great and useful dis-
coveries.

We know that aloes taken internally act as a very active
tonic, and are powerfully antiseptic when applied externally.
Surgeons daily use aloes in tincture, as a detergent for old
ulcers, caries, and gangrenes, which proceed rapidly. Would
it have this antiseptic property if taken internally ? We
know it besides for its febrifuge and purgative virtues : —
but it has certainly never been known before, that it ceases
to purge the instant it is united to gall-nuts in powder, as I
have had occasion to verify.

XL1II. A Fatal Case of Inguinal Hernia, by John Taun-
ton, Esq. Surgeon to the City and Finshury Dispensa-
ries, and to the City Truss Society for the Relief of the
Ruptured Poor.

To Mr. Tilloch.

Sir, uhould the following case of hernia (which was
attended with some important peculiarities) be deemed
worthy of a place in your valuable Magazine, the recording
of it will give me pleasure.

Mr. J. H. a^t. 53, an able-bodied man, of a good consti-
tution, has always lived a very regular life, and enjoyed
good health, has been subject to hernia in the left groin for
many years ; for which complaint he constantly wore a truss,
which prevented him from suffering any serious inconveni-
ence.

On the 5th of August, the intestine passed through the
abdominal ring, and formed a tumour of considerable size
in the left side of ihe scrotum. The tumour was very tense
and painful on pressure, but was apparently reduced with
considerable difficulty by a surgeon who resided near the pa-
tient.

The abdomen continued painful on pressure, the pain be-
ing referred principally to the umbilicus and region of the
stomach, with a sensation of heat. Fomentations and the
warm bath were emploved without any relief. The bowels
remained in a constipated state : no stool could be procured
either by medicines taken by the mouth, or by cathartic
glysters, several of which were injected.

The hiccough became very troublesome j every thing
taken bv the mouth was rejected by the stomach ; feculent
matter was vomited in large quantities; the tongue was

much

Fated Case of Inguinal Hernia. 231

much furred ; the pulse irregular, frequent, and intermit-
ted. There was also great thirst and fever.

The countenance became livid ; the eye had that peculiar
stare which often precedes death from strangulated hernia;
the extremhies became cold; the skin generally cold and
clammy, in a partial state of cold perspiration.

These symptoms ended in death in 13 days from the first
attack; nor does it appear (although the symptoms of
strangulated hernia continued from the beginning of the
•disease) that any attention was ever directed to the hernia,
beyond that of pressing the protruded viscera within the ex-
ternal abdominal ring on the first day of the disease.

The medicines were cathartics, opiates, saline draughts,
and glysters. Fomentations to the abdomen and the warm
bath were also used.

These particulars were related to me by two of the pro-
fessional gentlemen who attended him, as I did not visii#the
patient during life, but only attended to examine the parts
after death, when the following appearances were noted.

The whole of the thoracic viscera were, healthy. The
gall bladder was distended with bile, and contained several
small biliary calculi.

The liver, spleen, pancreas, and omentum were healthy;
the stomach, duodenum, jejunum, and ilium were much
distended with flatus. The jejunum and ilium inflamed:
.the inflammation increased as the intestines were turned
downwards to the left abdominal ring, through which a con-
volution of the ilium had protruded about twelve inches
before its termination in the ccecum. The protrusion
formed a tumour about as large as a middle-sized apple,
and situated on the anterior part of the spermatic process,
between the peritoneum and abdominal muscles, so as not
to form any tumour visible on the external part of the body;
but there cannot be a doubt but it might have been disco-
vered during the life of the patient by pressure.

The stricture was produced by the peritoneum only.

There were not any adhesions between the hernial sac
and intestine, nor had the sac suffered from chronic inflam-
mation. The portion of intestine contained in the sac was
highly inflamed, but not in a state of gangrene. The in-
testines below the stricture were empty and much con-
tracted ; the inflammation extended along the intestine
only about four inches below the part where the stricture
was situated.

The rest of the abdominal viscera were perfectly healthy.

The appearances, on dissectiou, of this case show, that

P4 if

232 Hoy at Academy of Copenhagen*

if an operation had been performed early, there is every rea*
son to suppose that the life of the individual might have
been preserved.

It also proves the necessity of carefully examining every
part of the abdomen usually the seat of hernia, when the
symptoms of that disease exist.

I cannot too earnestly recommend the early performance
of an operation in strangulated hernia, when it resists the
usual means of reduction *. For want of attention to this
circumstance alone, many valuable lives have been lost to the
community, and their families left unprotected ; their wi-
dows and orphans become a burden to the public, relying
for their support only on parochial assistance.
Sept. 26, lsio. John Taunton.

XLIV. Proceedings of Learned Societies*

# ROYAL ACADEMY OF COPENHAGEN,

J. his academy has proposed the following prize-questions
for 1810 : — In Mathematics. A body which has the form
and figure of a cylinder, such as Congreve's rockets, is pro-
jected at a certain elevation or angle with the horizon, and
is continually impelled by the flames which issue from it.
The substance which feeds the fire is gradually consumed,
and the weight of the body diminished. This being the
case, 1. What is the curve described by that body ? 2. If
the inflammable matter contained by the cylinder bums in
such a manner that the inflamed strata are neither parallel
to each other, nor perpendicular to the axis, to what per-
turbations will the rocket be. subject ? how are they to be
prevented or corrected ? 3. As it is necessary that the cy-
linder be perforated and hollowed, so as to afford the flame
a greater surface, and to increase the force of the flame that
issues from it, it is required to know what form or figure is
most advantageous for the excavation ? The society wishes
that attention be paid, if possible, to the resistance aud pres-'
sure of the air; but yet the prize will be adjudged to the
best answer to the above three questions.

In Natural Philosophy. — Philosophers have long be-
stowed great pains on seeking to discover the connexion
that subsists between electricity and magnetism, which ex^
hibit phenomena so similar and so different. Modern ob-
servations and discoveries have furnished new means of pro-

* Few, if any, would be the fatal cases in this .li&ease, If the time and the
performance of the operation were sufficiently attended to. — Hay's Observa-
tions on Surgery.

secutins

Royal Academy of Copenhagen. 233

secuting these researches. The older philosophers have left
, us numerous experiments on this subject, which do not ex-
actly correspond with the principles of the experimental
philosophy of the present day. Some philosophers have
made new and important experiment*, which have not been
sufficiently examined or repeated. The [loyal S' cietv, thinks
ing that this part of experimental philosophy may be consi-
derably improved, offers a prize-to the writer, who, taking
experience for his guide and support/ shall give the best ex-
position of the mutual connexion between electricity and
magnetism.

In Philosophy. — 1. There are persons who still deny the
utility or' physical doctrines and experiments in explaining
the phenomena of the mind and soul : others, on the con-
trary, contemptuously reject psychological observations and
reasons, in researches which relate to the body, or restrict
the application of them to certain diseases. It would be
useful to discuss these two opinions, to show and establish
more clearly how far psychology and natural philosophy
may be combined ; and to demonstrate, bv historical ev 1-
dence, what each of these sciences has hitherto 'contributed
to the advancement of the other. 2. The idea of an uni->
yersal and characteristic language, proposed by Leibnitz,
having never been sufficiently explained by himself, and ap-
pearing to have not been understood by any person, the
question is, to give an accurate and luminous designation of
that language, to point out the way that is capable of lead-
ing to this desirable object, and at the same time to examine
how far the methods hitherto tried in certain sciences, for
instance, in mathematics and chemistry, might be correctly
applied to philosophy and J^e other branches of human
knowledge. For the best answer to each of these questions
the academy offers a cold medal of the value of ilfty Danish
ducats. Answers to all, except the last, the term of which
is extended to 181 J, must be sent before the conclusion of
1810, either in Latin, French, English. German, Swedish,
or Danish, toM. Buyge, professor of astronomy at Copen-
hagen.

WERNERIAN NATURAL HISTORY SOCIETY,

At the meeting of this Society, on Saturday 2»st of July
last, Mr. Campbell of Carbrook re 'd some observations on
the cause of the antilunar or inferior tide, impre»>ing the
Newtonian theory on that subject; and Dr. Thomas Thorn*.
son read an account of two natural combinations of hydro-
gen and carbon, viz. carburetted hydrogen and supercar-
buretted hydrogen, neither of them containing anv b.xygen^

xlv://2.

I 234 ]

XLV. Intelligence and Miscellaneous Articles,
To Mr. Tilloch.

Sie, An extraordinary accident lately happened to my
neighbour, Mr. Watts, chemist, in the Strand, which has
excited the attention of several persons of his profession. I
am anxious your ingenious readers should know some par-
ticulars respecting it ; and if you will indulge me by insert-
ing briefly an account of the affair, I shall feel obliged, as
it might in future prevent a more serious evil.

Mr. Watts had taken into his premises, as usual, a car-
boy of aquafortis, and from some unknown cause, the fo|-
jowing morning, his warehouse appeared to be on fire;
there being a great quantity of smoke seen issuing from
many parts of the building. On entering the apartment,
the carboy was on fire, and more than half consumed. I
saw the remains of the basket and straw taken into the
yard. The air quickly revived the fire, and I have no
doubt but I could very easily have blown it into a flame.
Particular inquiry was made respecting the straw, and it
appears to have been perfectly clean and new. There was
no turpentine, or other inflammable spirits, within a foot
of the spot where the carboy stood ; and it has very much
surprised all who have seen it, how the acid could ignite
such materials without the aid of other agents. Perhaps
some of your scientific correspondents can assign a cause
for this strange event, which does not appear to be gene-
rally known, and may point out a remedy for preventing a
more serious conflagration. I am, sir,

Your obliged humble servant,

Lancaster Court, Strand, J{t TeeD.

11 September, IS 10.

The French Government has recently ordered all the
superb remains of Roman architecture at Nismes to be
cleared from the rubbish with which they have been for
several centuries confounded. All the modern buildings,
which disfigured these monuments of antiquity, have con-
sequently been removed, and the decayed or ruinous parts
of the original architecture have been strengthened and
repaired.

BETHLEM HOSPITAL.

Application was made to Parliament, in the last session,
for an Act to enable the Governors of Bethlem Hospital to

exchange,

gethlem Hospital. 23$

fcXchange, with the City of London, the present contracted
site of the hospital, for a piece of ground, containing nearly
twelve acres, 9itualed in Saint George's Fields; on which
£pot the unhappy Subjects of mental derangement will, in
addition to their former advantages, possess such superior
requisites of air and exercise as they have never yet enjoyed,
which are not only likely to add in a considerable degree to
their comfort, but also to accelerate their cure. The plan
of the ancient structure is very capable of improvement,
and has long inueed required it. The Governors therefore
have advertised for plans for the new building, and offered
premiums of jf .200 for the best, £.100 for the second, and
£•60 for ihe third best designs, in the full confidence of
being adequately assisted in their anxious desires to erect
an hospital which may be at once a monument of a bene*-
volent and enlightened age, and an honour to a great and
distinguished nation. — The present intention of the Go-
vernors is to erect a building capable of containing four
hundred patients, but not to confine themselves even to
tfyat enlarged number, if they shall be enabled, by ihe libe-
rality of the public, to proceed further in their design. — The
funds of the hospital, which are applicable to the purposes
of a new building, amount, however, at this time, to little
more than £.27,000, while the cost of a new hospital,,
upon the scale proposed, can hardly be estimated at a
smaller sum than £. J 00,000. — To effect, therefore, so de-
sirable a purpose as that in view, it will be obvious, that
nothing short of a liberal subscription on the part of the
public at large can suffice. The Governors have therefore
published an address, most earnestly entreating all corpo-
rate bodies, as well as individuals, throughout the kingdom,
to contribute, by their benevolence, more extensive means
of relief and cure, than have ever yet been afforded, to the
unfortunate subjects of the most afflicting malady with
which it has pleased the Almighty in his wisdom to visit
his creatures. Their appeal we are confident will not be
in vain, in a country whose greatest characteristic is its
noble and generous solicitude to alleviate the miseries,
administer to the .necessities, and heal the diseases of its
people.

Subscriptions are received by Richard Clarke, Esq,
Chamberlain of London, (the Treasurer of Bethlem Hos-
pital), Bridge Street, Black- friars; and by most of the
banking-houses in London.

MATilE-

236 Mathematics. — Portrait of Buchanan*

MATHEMATICS. s

It is well known to mathematicians, that the doctrine of
solid angles was left in a very imperfect state by Euclid, and
has scarcely at all been advanced by subsequent geometers 5
one of the latest commentators on Euclid, Professor PI ay fair,
having remarked that " we have no way of expounding,
" even in the simplest cases, the ratio which one of them
"bears to another. " Dr. Gregory, of the Royal Military
Academy, has recently invented a theory of solid angles,
which is at once simple', satisfactory, and universal in its
application. By means of this theory, the relative mag-
niludes of solid angles may be ascertained, not only when
they are of the same class, — as those formed by the meeting
of three planes, those by the meeting of four planes, the
angles at the vertices of cones, &c. : but angles of one
class may be compared with those of another, with respect
to magnitude; and their mutual relations determined, by
processes as obvious and elementary as the usual operations
in Plane Trigonometry. He finds, for example, that the
solid angles of the regular tetraedron, octaedron, hexae-
dron, and of the right-angled cone, are denoted by the
numbers 87*7361 1," 216*35185, 250, and 292*89322, re»
jpectively ; the maximum limit of solid angles being ex-
pressed by 1000,

Having been favoured with a most exquisite original por-
trait of Buchanan, by Titian, we have procured it to be
engraved by Woolnoth in his best manner, as one of the
embellishments of the present Number. Such of our readers
as wish to possess proofs (of which a few have been worked
oiT) of this admirable likeness may obtain them from the
Publishers of the Magazine, at five shillings each.

Xotice respecting the Preface to the 4th Edition of the
Encyclopaedia Britannica .
In writing the preface to the Encyclopaedia Britannica,
some mistakes having occurred, relative to the writers en-
gaged in the publication, the conductors of that work beg
leave to assure their subscribers and the public, that they
are v* holly unintentional ; as it never could be their design
to detract, in any way, from the merits of the authors
whom they employed. They understand, in particular,
from Dr. Kirby, that the article Physiology , attributed by
mistake to another gentleman, was written by him ; and
that the following articles, viz. Farriery, Geography,

Geology)

Treatment of Hernia— Lectures. 237

Geology, Materia Medica, Prescriptions, Russia, Amuse-
ments of' Science, and Spain, were also contributed by him.
This notice is to be printed separately, and may be ,had
by the subscribers to the Encyclopaedia, from the Pub-
lishers of that work in London and Edinburgh.

Rupture is so general a disease, and in its aggravated state
so frequently and suddenly fatal, that every information
which promises relief, particularly from the regular prac-
titioner, ought to be universally known. We therefore give
the following extract from a work lately published by Mr.
Edward Geoghegan, in which an improvement in the treat-
ment is suggested. — " I place the patient in a recumbent
position, wiTh his shoulders a little raised to relax the trunk,
but the pelvis not raised, as that would put the fasciae on
the stretch. The knees are to be drawn up. If the parts have
not been irritated by handling them, or the body disturbed
by jolting it about, or by any such roughness, I proceed
directly to apply cloths wet with cold water, expose the
entire body naked to the air, the doors and windows being;
open. This practice usually succeeds within an hour*. If
it does not, I surround the hernia with my hand or hands
at about its middle, in the way that I would grasp a gum
elastic bottle, to press out its air or other contents, by
gently approximating its sides, always holding in view',
that the tumour is to be emptied, ana not pushed up. I
never press the hernia in any direction, or at all towards
the abdomen. When it is small, it may be done with the
finger and thumb of one hand. Having applied the hands,
I do not remove them for fifteen or twenty minutes, aware
that reiterated impulses irritate, and that the effects of
compression are lost each time that it is intermitted. :' — In

cases of great pain and tension he omits this practice. .

This practitioner differs from every other so far, as that the
usual directions are to press the protruded bowel up towards
the belly, which he takes great pains to show is improper,
and insists that the contents should be merely squeezed out.

LECTURES.

Dr. Adams's Lectures on the Institutes and Practice #f
Medicine will commence on Monday theSth Oct. next, at
Eight o'clock, at Dr. Anderson's Lecture-rooms, 47, Frith*
street, Soho. ,

* In some cases where I could not immediately attend, I have directed
th;it cold applications should be used until my arrival* and after an hour
they informed me that they were seized with a shivering, that they heard
the wind rash out of the hernia, and that they were instantly relieved

On

i$9 tecturc*.

On the sam£ day Dr. Anderson will begin his Course
bf Lectures on Practical Chemistry.

Lectures oil. Materia Medica form a part of the above
Courses.

Further particulars may be known by applying to Dr,
Anderson, as above, or to Dr. Adams, 2, New Bridge-
street.

Dr. Clutterbuck will begin his Autumnal Course of
Lectures on the Theory and Practice of Physic. Materia
Medica, and Chemistry, &c. on Friday the 5th October,
at Ten o'clock in the morning precisely, at his house,
No. J, Crescent, New Bridge "street ;_ where further par-
ticulars may be had ; or at the General Dispensary? Al-
dersgate-street. The Lectures are given daily ; Theory and
Practice, Mondays, Wednesdays, and Fridays ; Materia
Medica and Chemistry, on Tuesdays, Thursdays, and Sa-
turdays, at the same hour.

George-street, Hanover- square; and St. George's Hospital,
On Saturday, Oct. 6, a Course of Lectures on Physic
and Chemistry will recommence in George-street, at the
usual morning hours : viz. Therapeutics at Eight, the
Practice of Physic at Half after Eight, and the Chemistry
a Quarter after Nine, hy George Pearson, M.D. F.R.S.
Senior Physician to St. George's Hospital, of the College
of Physicians, &c.

Clinical Lectures are given, as usual, on the Patients of
St. George's Hospital, every Saturday morning at Nine
o'clock.

LIST OF PATENTS FOR NEW INVENTIONS.

To Charles Williams, of Gravel -lane, South wark, mill-
wright, for a machine for grinding or cutting malt, splitting
beans, and any other kind of grain, and various other arti-
cles.— Aug. 2, 1810.

To Marc Isambard Brumel, of Chelsea, for certain ma-
chinery for the purpose of making or manufacturing shoes
and boots. — Aug. 2.

^To Thomas Collins, London, warehouseman, for an im-
proved mode of making ladders, which being formed of
different pieces, and capable of being put together by socket
joints, will be found extremely useful for the purposes of
escalade, engineering, escapes from fire, erecting of build-
ings, and for all other purposes for which ladders of any
description are necessarv. — Aug. 10.

To

List of Patents for ?iew Inventions, 23|

To William Whitmore, of Dudmarton, Salop, esq. for a
magnetic toy to facilitate the teaching of children to spell,
read and cypher, in any tongue, with ease to the teacher,
pleasure to the children, and proportional expedition. — -
Aug. 14.

To Peter Durand, of Hoxton Square, merchant, in con-
sequence of a communication made to him by a certain
foreigner residing abroad, for a method for preserving ani-
mal food, vegetable food, and other perishable articles, a
long time from perishing or becoming useless. — Aug. 25.

To James Walker, of Wapping, in the county of Mid-
dlesex, ship-chandler, for his machine or vessel for the safe
conveyance of gunpowder, and for its preservation from
injury by damp. — Sept. 7.

To James Weldon, of the county and city of Litchfield,
engineer, for his further new improvements on a mill for
grinding bark and other articles. — Sept. 7.

To Joseph C. Dyer, of Boston, State of Massachusetts,
one of the United States, now residing in the city of West-
minster, merchant, who, in consequence of a communication
made to him by a certain foreigner residing abroad, is be-
come possessed of a machine for cutting or removing all
the various kinds of furs which are used in hat-making
from the skins or pelts, and for cutting the said skins or
pelts into strips or small pieces. — Sept. 7»

To David Mathews, of Rotherhithe, engineer, for his
improved method, of constructing and building locks with
a groin or Gothic conic arch. Also an improved form of
the gates, and an improved method of opening and shutting
the same. — Sept. 7»

To Joseph Johnson, of the county of Surry, gentleman,
for his new mode of communicating intelligence from one
apartment of a house to another by means of machinery or
apparatus, which he denominates a domestic telegraph. —
Sept. 17.

To Jonathan Varty, of Liverpool, coach-maker, for his
improvements in the axle-trees of carriages. — Sept. 17.

To Peter Brown, of Henrietta-Street, Covent-Garden,
Middlesex, gentleman, for his new construction of buoys
for ships or vessels, and for mooring-chains or similar pur-
poses.— Sept. 26.

To Richard Seaton, of Berwick-Street, Middlesex, liquor-
merchant; and Thomas Rice, of Whitecross-Street, Mid-
dlesex, spring roasting-jack-maker, for their new burner
upon an improved construction, applicable to all kinds of
lamps. — Sept. 26-

METEO-

7

no

Meietrofogy.

meteorological table,
By Mr. Carey, op the Stra
For Septetiiler 1810.

NDa

The

rmormiter.

'

r^\i .

Days of
Mouth*

51

c
o
c

o ,

CJ "boo

Height of
the Barom.

eesof'Di
l>y Lesli
rometer

Weather.

^ c

CO ^

£

*2^

Inches.

Degr
ness!
Ilyg

0

August27

58

74°

62°

30'()8

63

Fair

28

57

74

64

•13

74

Fair-

99

58

71

67

•10

65

Fair

30

59

75

68

29*98

52

Fair

3i

66

77

69

•90

53

Fair

Sept. 1

68

78

70

•85

61

Fair

2

70

80

69

•90

BO

Fair

3

69

72

58

•80

58

Cloudy

4

58

62

54

•72

26

Cloudy

5

55

68

58

30-00

55

Fair

6

56

68

51

•00

45

Cloudy

7

50

64

49

•32

51

Fair

8

49

64

50

'12

55

Fair

9 51

68

56

•05

50

Fair

10

53

68

54

29*91

41

Fair

1!

50

59

50

•70

0

Rain

' 12

58

58

45

•61

0

Rain

13

48

63

47

30-06

36

Fair

14

52

68

48

•20

42

Fait

15

47

61

51

•38

33

Cloudy

16

53

64

57

•28

42

Cloudy

17

57

67

58

•09

38

Fair

18

58

6'S

49

•05

30

Cloudy

Iff

51

67

56

•10

22

Cloudy

20

56

63

59

•10

10

Foggy

21

58

66

53

•05

15

Foggy

22

56

68

56

29'95

32

Fair

23

57

62

52

•96

20

Showery

24

56

66

54

30-09

42

Fair

25

58

69

56

•11

80

Fair

26

57

67

5 5

•05

82

Fair

1

-J.B.T

he Bar

ometer

a height is ta

ken atom

i o'clock.

[ 241 ]

XLVt. On the New Mountain Barometer. By Sir Henry
C. Englefield, Bart. F.R.S. and F.S.A.

To Mn Tilloch.

Sir, JL he experience of three years having ascertained the
convenience and utility of the mountain barometers, made
on the principles of which a description, drawn up by me,
was inserted in your Journal, (vol. xxx. p. 46,) I am induced
to address you again on the subject ; both to inform the public
~f some improvements made in their construction since my
former letter, and to propose some mode of collecting, for
general^enefit, the observations made by individuals.

The improvement in the construction is principally hi
the cistern. It had been found that when exposed to great
motion in an unfavourable position, which in long journeys
is not easily avoided, the agitation of the mercury had
several times cracked the tube towards the top, in a fissure
scarcely perceptible to the eye, yet sufficient to Jet in slowly
a small portion of air. To remedy this inconvenience, the
cistern has now a bottom of leather on which a screw presses
in the usual mode, so as to force the mercury nearly to
the top of the tube when packed for carriage. This screw
is to be unscrewed as far as it can, when the barometer is
prepared for use; and the leather bag is so adjusted, that
there is no reason to fear that the capacity of the cistern
thus unscrewed for use, will ever be sensibly different from
itself at different times. It may be just mentioned, that
when the barometer is carried by a careful person, it is by
no means necessary to screw up the bag between every
station; as, when unscrewed, the instrument is in precisely
the same state that it always was, in those of the first con-
struction*.

Mr. Jones, at the desire of several gentlemen, has en-
deavoured to add a gauge point and adjustment to keep the
mercury in the cistern ever to the same height, as -in other
mountain barometers, but such addition has been found in
practice productive of more inc onveniencc than advantage.
He now, therefore, measures the content of every tube se-
parately, and engraves on the mounting the correction to
be made to the results, as stated in the former paper; and
by this method it is presumed that all errors from the
want of a gauge point must be prevented. Mr. Jones has

* The screw which frees the cistern for use, is protected by an outer cap
from being spoiled by idle curiosity, or irjurcd by a blow, which often
happened to those barometers where this screw was unprotected.

Vol. 36. No. 150. Oct. 1810. Q now

942 On the New Mountain Barometer,

now sold above 150 barometers of this construction. Of?
these, it cannot be doubted that by far the greater part ha^
been purchased by gentlemen both able and desirous to
use them for the purpose of measuring heights ; and 1 know
that a great number of valuable observations have been
made with them in different parts of our islands. While,
however, these observations remain in the hands of the
observers, the public is little benefited by them; and I
doubt not that if it were generally known that a deposit
for them was provided, all those gentlemen who have made
observations of altitudes with these, or any other go- ?
mountain barometers, would readily send their observations,
and contribute their part to the common stock of valuable
information which would be deduced from the publication
either of the observations themselves or the results of them.

For this purpose Mr. Jones, late of Mount- street, now
of Kenton-street, Brunswick-square, the same ingenious
artist who made these barometers at first under my inspec-
tion, has kindly consented, at my request, to receive and
arrange all such observations as may be transmitted to him
(post paid or franked) by the gentlemen who have made
them ; and I shall be happy not only to assist him in com-
puting them, but will readily superintend the publication
of them, either in the literary journals, or in a separate work,
as may in process of time appear the most eligible. It seems
the most desirable that the names of the observers should
be published with their observations, as giving the stamp
of authenticity to them : this, however, will be done, or
omitted, as the several contributors may wish.

As it is to be hoped that the communications may be
numerous, it will materially diminish the labours of ar-
rangement, if a general form be adopted in sending the ob-
servations; and it is hoped that the specimen here annexed
will be found convenient to the observers themselves, as
well as to those whose province it maybe to collect them.

Extensive geological observations would be in this case
out of their place; yet it might be useful, and productive
of little additional labour or trouble, if the soil of the spot
where each observation was made could, if possible, be
specified. Another observation nearly connected with that
of the barometer and thermometer for altitudes, is the
temperature of the waters at or near the places of observa-
tion. Wells of 40 or 50 feet deep are, for this purpose,
more to be depended on than springs, which often run at
so small a depth below the surface of the ground as to be
much affected by the heat and cold of summer and winter.

It

On the Land Winds of Coromandel, &c, 243

It will, however, be best to make observations as often as
possible both on the one and the other, as it has been as-
certained, both by Mr. Cavendish and the late Dr. Hunter,
that the temperature of the waters at any given place is a
most accurate measure of its mean heat ; a determination
of which is not only an object of considerable curiosity in
itself, but of very great consequence in an agricultural point
of view.

The annexed form for registering the observations scarcely
requires an explanation. The first column is for number-
ing the observations, which extremely facilitates the re-
ference to them. The succeeding columns are fully ex-
plained by their titles. The last, called Results, is added,
in order that those persons who choose it may place in one
view the observations, and the altitudes deduced from them.
Printed sheets in this form, ready for use, may be had of
Mr. Jones. The back of each page is left blank, for the
convenience of inserting any other notes or observations.
I am, sir,

Your humble servant,

H. C. Englefield.

N°

Place of
Observation.

Wea-
ther,

Wind.

Time

Barome-
ter.

<

Q

Results.

1

2

3
4

October 6

Steyne, Bright-
helmston . .

Stand on Race-
ground. . . .

Stand again . .

Steyne again . .

}
i

Sun

Do.

Do.

Do.

1

NW

Do.

Do.
Do.

2*15

3*0

3*32
4*15

30*268

29*870

29*861
30*278

63

61

63

52

61
61

1 and 2
400 feet.

XLVII. On the Land Winds of Corom.andel, and their
Causes. By William Roxburgh, M.D.*

JL he land winds on the coast of Coromandel are those
hot winds which blow at a particular season of the year,
and hour of the day, from the western hills, commonly
called the Ghauts, towards the Bay of Bengal. In the
more inland countries, as above the Ghauts, "they are not

* From Transactions of the Medical Society vf London, Vbl. i. part I. just
published.

Q 2 confined

244 On the Land Winds of Coronlandct,

confined to any regularity, though they are fe!t sometimes
with a great degree of severity, and for hours together.

I understand also that in the upper parts of Bengal they
are sometimes experienced vcrv severely ; hut whether from
the west or the northward, or irt what part of the year, [
have not been able to ascertain. As far as this only tends
to prove the insufficiency of the denomination, h would
signify little, although in other respects it would be of
more moment.

As they are generally supposed to be peculiar to this
country, and are felt during several months in the year, we
should imagine their history and causes to have been per-
fectly investigated and understood ; but, I know r.ot why,
neither the one nor the other have as yet been satisfactorily
explained.

The most plausible reason generally given for the great
accumulation of heat in them is the heat of the season in
which they prevail, and the long tract of country over
which they have to pass. That this, however, is not the
true cause, it shall be my endeavour to demonstrate; to
which I will add an attempt to point out the most probable
one, founded on known chemical principles.

Respecting the theory I have to offer, I regret that it has
found but few patrons in this'country, which, however, I
flatter myself may be ascribed more to the manner in which
it has been proposed, than to the foundation on which it is
constructed.

In order to facilitate the explanation of mv sentiments,
as well as to show thlt the land winds really deserve some
attention from the philosopher, I shall briefly recount the
phenomena accompanying their beginning and progress,
as well as the effects by which they are generally followed.

Could my pen equal my sensations, I should be able to
paint their effects in the most lively colours, aided by eight
rears experience in a country the most noted on the coast*
for their intensity.

The land winds are preceded in the latter end of March
or in the beginning of April bv whirlwinds, which between
eleven and twelve o'clock at noon hurrv in various direc-
tions, mostly from west to east, towards the sea. These are
called by the natives Peshashs or Devils, because they some-
times do a little mischief to the lighter buildings.

About the same time," or a little after the appearance
of the whirlwinds, we may observe all ranges of hills gar-

* Sarr.ulcotah in the Northern Circars.

. * imbed

(ml Ihelr Causes. 245

ntshed as it were with clouds, which become daily darker
and heavier, until they discharge themselves with much
thunder and lightning in a heavy shower of rain. After
this marked phenomenon the land winds set m imme-
diately with all the violence of which they are capable.

Their commencement is generally in the lat'.er end of
April, or beginning of May, and their reign lasts to the
earlier days of June, during which period they generally
cx^rt their violence from ten or eleven o'clock in the morn-
ing until about three or four o'clock in the afternoon.

In this season the atmosphere is commonly hazy and
thick, except that in the evenings and nights the sky is
serene and clear, provided the land winds do not continue
the whole day.

The rising sun which portends a land wind day appears
of a fiery red, and as if involved in mist, which mist is
changed afterwards into clouds that lie heavy on the
Ghauts.

The land wind of each day is almost always preceded
by a long calm, and immediately by a cloud of dust.

Their diurnal violence is terminated along the coast about
two or three o'clock, by the setting in of the sea-breeze,
which wafts delight and health as far as its influence ex-
tends, which is not more than ten or twelve miles inland.
An abatement of their intensity from thence to the Ghauts
is all that can be hoped for.

The sea-breeze regularly begins in the afternoon at one
or two o'clock, blowing pretty steadily until sunset, when
it dies away gradually, and at sunrise it is again perceptible,
though weakly.

Wnen I say its influence is only felt ten miles inland, I
do not wish to be understood that it does not extend iur-
ttier : I mean only its powerful refreshing properties, which
it loses in proportion to the distance from the sea, and in
an inverse ratio to its strength, which is not great. In
general it arrives at thirty miles distance from the sea in
the evening, and is then only agreeable by the ventilation
it effectuates.

In the country above the Ghauts, as in Mysore, the cast
wind prevails also in the afternoon, but from a period muc.li
earlier, orcotemporancous with the sea-breeze on the coast,
which renders it clear that this inland breeze either does
not extend further than to the Ghauts, or redly originates
there; a point which deserves to be ascertained, as another
phenomenon depends upon this circumstance.
'" ' ()3 Should

246 On the Land IV bids of Coromandel,

Should the sea-breeze fail, as sometimes happens, the
land wind decreases gradually until it dies away in the be-
ginning of the night, which, on account of its calmness, is
dismal to a degree : next morning, a little motion of the air
is again perceptible, but at the usual time the wind sets in
as strong and hot as the day before. Every thing we put our
hands upon is then distressing to the touch, which must
be the case when the temperature of the body is inferior to
that of the atmosphere. This we experienced for almost a
fortnight in the year 1799 in the Northern Circars, when
the thermometer at eight o'clock in the night stood at
108°, and at noon at 1 12°. Shades, globes, tumblers, then
very often crack and break to pieces, and the wooden fur-
niture warps and shrinks so much, that even the nails fall
out of doors and tables, &c. In their greatest intensity,
however, I have never seen the thermometer rise higher
than 1 15°, viz. in the coolest part of the house, though
some say they have observed it at 130°.

The Ghauts, and the hills at no great distance from them,
are then seen lighted all night by spontaneous fires, and
often in a very picturesque manner.

These illuminations appear, in general, about the middle
of the mountains, and seldom or never extend to the topv
or bottom of them. They take place especially on those
hills on which the bamboos grow very thick; which has
probably led the natives to explain this phenomenon so
rationally, by ascribing it to the friction of these bushes
against each other.

Lieutenant Kater, of his majesty's 12th regiment, thinks
that the corky bark of the adenanthera pavonina is often
spontaneously inflamed, as he has frequently found, on his
surveys, its bark converted i into charcoal, and several of
these trees burnt clown to the roots, although they were
not in the vicinity of any other trees.

In Europe 1 know these spontaneous ignitions have been
much discredited ; and I doubt not but should these few
sheets ever be published, many objections will be raised
against what I have related : but 1 have endeavoured to
state tacts only, which a luxuriant imagination might have
painted in more striking colours, but I am sure not with
stricter adherence to truth.

The land winds are noted for the dryness which they
generally produce on the face of the country, as well as on
that of the animal creation. This sensation is particularly
felt in the eyelids^ which become in some measure quite

stiff

and their Causes. . 447

stiff and painful. This is owing to the immediate volatili-
zation of all humids that irrigate our organs, and which, in
this particular one, probably gives rise to inflammations of
the eyes, so frequent at this time of the year*.

The continuance of this wind causes pain in the bones,
and a general lassitude, in all that live; and, in some, pa-
ralytic or hemiplectic affections. Its sudden approach has,
besides, the dreadful effect of destroying men and animals
instantaneously.

It is not very uncommon to see large kites or crows, as
they fly, drop down dead ; and smaller birds I have known
to die, or take refuge in houses, in such numbers, that a
very numerous family has used nothing else for their daily
meals than these victims of the inclemency of the season
and their inhospitality. In populous places it is also not
very uncommon to hear, that four or five people f have
died in the streets in the course of a day, in consequence of*
being taken unprepared. This happens especially at the first
setting in of those winds.

The natives use no other means of securing themselves
against this wind but shutting up their houses, and bathing
in the morning and evening ; Europeans cool it through
wetted yatsj made of straw or grass, sometimes of the roots
of the wattie§, which, wetted, exhale a pleasant but faint
smell. It will be incredible to those that have never wit-
nessed it, but the evaporation is really so great, that several
people must be kept constantly throwing water upon the
tats (eight feet by four) in order to have the desired effect
of cooling a small room.

Tt would be scarcely necessary to observe, if it were not
in contradiction to public opinion, that the cold produced
is not a peculiar property of the wind, but depends upon
the general principle, that all liquids passing into an aeri-
form state absorb heat, and cause immediately around them

* The eye flics, so often supposed to occasion it, produce a transient and
sharp pain in the eye, but never, I believe, a lasting inflammation.

It is generally thought infectious, and may be so by the interference of
the eye flies carrying the contagious matter from an affected eye to a sound
one.

f Four people dropped down dead at Yanam, in the year 1797, an hour
after my arrival there from Masulipatam: and at Samulcotah tour or five
died the same day on the short road between that place and Peddapore: the
number of inhabitants of either of these places does not exceed, I believe,
five thousand.

t The frame of them is made of bamboos in the form of the opening in
the house to be tatted, let it be door or window, which is then covered
with straw in the manner every one thinks best suited to retain the water
longest.

§ AiidTopagonmuricatiim,

g4 aoV

248 On the Land Winds of Coromandel,

a diminution of it, and consequently a relative coldness*
On the same principle depends also the cooling of wine
and water, in the land wind seasons, the latter in light
earthen vessels which allow an oozing of the water through
their pores, and the former in bottles wrapped in a piece
of cloth or in straw, which must be constantly kept moist-.
ened.

The great violence of these winds is at last terminated
by frequent showers of rain, in June, in the low countries*
and by the greater quantify of the regular rains falling in
the inland countries, which seem to suspend the partial
formation of clouds along the Ghauts, and to leave them
clearer, and visible at a greater distance than they had been
at any other period of the year before.

After the enumeration of so many disagreeable circum-
stances, I am naturally led to an investigation of the causes,
that produce them. Before this can be done, however, I
must prove, according to promise, that the theory of our
philosophers is founded in error.

They ascribe, as already observed, the extraordinary heat
which distinguishes these winds from most others, to the
absorption of caloric in their passage over an extensive
tract of country, at a time when the sun acts most power-
fully in our latitudes.

According to this theory, the heat should increase in
proportion to the space over which this wind is to travel ;
it should be hotter on the coast than it is at any. part of the
country inland, or, which is the same, it should decrease
by degrees from the eastern to the western sea of the penin-
sula. Experience, however, teaches us the reverse ; for
it is hottest near the Ghauts, and among the valleys between
those ranges of hills, than at any place on the coast ; and
the heat of those winds decreases also as they approach the
Bay or' Bengal, and in a direct ratio from the Ghauts to the
sea : accordingly, it is at Amboro* hotter than at Velloref,
and at this place again than at Arcot J, Conjeveram §, and
jVladras, where the land winds are seldom felt with any de-
gree of severity.

* A place situated in the most western valley of the Ghauts, immediately
at the foot of the steepest ascent into the Mysore country.

+ Lies in a spacious valley nearly at the entrance of the Ghaut mountains,
and has the advantage of an open communication with the flat country to
the north-east.

\ A large city> the capital of the nabobs of the Carnatic, east of the ranges
of hills called the Ghauts.

§ . . . miles east of the latter place in the road to Madras, a large popu-
lous place. I have chosen this tract or line as the most known, although
not the hottest ; for EUore, Rajahmundry, and Samulcptah in the Northern
Circars, are by far more exposed to these winds. Time

and their Causes. * 249

' . Time is another measure applicable to the acquisition" of
beat, as it increases to the greatest pitch which a body is
m capable of receiving in proportion to its continuance: the
land winds should therefore be cooler when they set in at
ten or eleven o'clock, and hottest at their termination in
the afternoon ; they should be so at least at noon, when
the sun is nearlv vertical, and has the greatest influence oti
the substances from which heat is to be attracted. The
contrary, however, comes nearest to the truth ; for it is
known that these winds set in with their greatest violence*
and heat at once, which rather abate than increase, as
might be expected.

We should, on this principle, further suppose the heat
v/ould increase gradually with the return of the sun to our
latitudes, from its southern declination, and stand always
in proportion to its position. We find, however, that ex-
perience also contradicts this point of the theory under dis-
cussion; for after the sun has passed our zenith*, the land
■winds set in at once with all their intensity, in the manner
before described, and they cease as abruptly before its re-
turn again f .

A material change in the temperature of this climate is
certainly effected by the approach of the sun from the south ;
but the heat which is thus caused, and which increases
by imperceptible degrees, is never so great, and is only felt
by those who expose themselves to it unprotected; for the
air remains proportionally cool, and our houses afford, in
this season, a pleasant retreat. We find it far otherwise
in a land wind ; for this penetrates our inmost recesses, and
renders life miserable every where.

I have before observed, that winds equally hot with those
of periodical duration are felt in all parts of the 'country,
and at different seasons; a circumstance alone sufficient,
if proved, to overthrow the groundwork of the old theory.
For a confirmation of this, I will appeal to the general
. observation, that immediately before a long rain the weather
fs sultry, and that a single shower is always preceded by a
warm disagreeable wind.

We are very particularly reminded of the approaching
great monsoon in October by the oppressive'heat we have in
the calm evenings of that month, which, I am persuaded,
would equal that of the land winds in May, if the atmo-

* The sun is in the zenith at Madras about the 2Cth of April,
f The sun is again in our zenith on its southern, declination about the-
J Oth oi Auguft.

sphere

250 On the Land Winds of Coromandel,

sphere was not coaled in the latter part of the night by
breezes that have wafted over extensive inundated plains.

I can refer, secondly, to my Meteorological Journal,
according to which, the 4th of June 1800, at Madavaram,
a place not far from Bengalore, the thermometer rose for a
short time to 104° just before a slight shower of rain, and
at a time when heavy clouds darkened the western hemi-
sphere.

Further, in the months of March and April, 1 804, wc
had often at Bengalore, in the afternoons, strong gusts of
wind from the eastward, which, in common, were styled
land winds, and were really as hot and disagreeable as mo-
derate land winds are in the Carnatic. 1 eould have mul-
tiplied instances of this kind, but am of opinion that in a
fact so much known it would be perfectly needless.

The last refuge of the defenders of this theory is the
valleys of the Ghauts, in which they pretend the heat is
generated by the concentrated and reflected rays of th^
sun.

I will not deny but the heat occasioned by these causes
may contribute much to raise the heat of the land winds;
but the sudden appearance of the latter, their usual strength,
and abrupt disappearance, all militate against that explana-
tion as a principal cause.

The heat of these winds should in this case, to say a few
words more on the preceding subject, decrease regularly
from the point where it is greatest towards the opposite, on
both sides, as is the case on the coast of Coromandel. On
the contrary, we find that, immediately on our having
ascended the Ghauts, or on the top of hills * elevated above
the clouds, we have escaped their heat all at once. It is
hereby remarkable, that the direction of the wind remains
to appearance nearly the same every where. In Mysore,
for example, the wind is, in the land wind season, west
during the greater part of the day; in the afternoon it is
from the east, and commonly warmer than the former.

This, together with what had been said before, will, I
hope, be thought sufficient to establish my opinion re-

* MaJQT Lambton, at the top of Carnatighur, one of the highest hills m
the Carnatie, about three thousand two hundred feet above the level of th«
sea, found, in the middle of the land wind season, the therxnotnetei at 79° and
W in the mornings, and, at noon, 82° and 84°, when it was below at 103*
and more.

This observation may be the more depended upon, as the Major remained
for a considerable time on the top of this bill, in the pursuance of h; ntost
accurate survey, in the course of which he pays great attention to this as
we'd as (o all other points that could influence his learned labour;:.

lativc

and their Causes, , 25 1

lative to what can not be the cause of the heat in the land
winds.

It remains now to point out a theory., supported on a
firmer basis, which I shall endeavour to do in the follow-
ing pages. It is founded on a chemical principle, and will
explain, I think, the heat of these winds in a satisfactory
manner.

The principle itself needs no demonstration, as it is ad-
mitted as a general law ; viz. that " all bodies, when they
become more dense, suffer heat to escape ; or, what is the
same, they give out heat." For example, when gases or
aeriform substances become vapours, they discharge as
much heat as was necessary to keep them in their former
gaseous state : further, vapours in condensing into fluids
are known to do the same, as also fluids, acquiring solidity.

I am sorry that the quantity of heat set free in the con-
v densation of vapours required for a pound of water has
escaped my memory; but I recollect it was very considera-
ble. We know, however, that a great deal of it is re-
quired for the evaporation of the same measure, and it is
but reasonable to admit that the same quantity with which
it has combined should be discharged oa its returning to
its former state of fluidity.

In order to apply this principle to explain the presence
of heat in our land winds, I must first observe, that the
atmosphere in January, February, and March, is perfectly
clear and serene; and then I will call to mind what has
been said of the phenomena of those winds, that they are
preceded by clouds on and among the Ghauts, and that a
heavy shower of rain from that quarter announces their ar-
rival; that during their continuance clouds are observed to
lie on the Ghauts ; and that the atmosphere, even in the
low country, is hazy and thick. I must add also, that the
countries west of the Ghauts are at this season frequently
visited bv heavy showers of rain, accompanied with much
thunder and lightning, and sometimes with hail. Here in
the Mysore country I have found the heaviest showers of
this kind to come from the north-west*, which is exactly
in the direction of the countries remarkable for the great
heat of the land winds in this season. At times, wc have
also showers from the east and south-east, and my attention
shall not be wanting to ascertain whether it is not at the
time when the land winds blow hottest in the Carnati-j.

* The hottest land winds in this season ( 1 S04) at Madras were, I uader-
stand, from the north-west ; which corresponds with the direction trom which
the rains came in Mysore at that period.

By

ffrg On the Land Winds of Coromandel, and their Causes,

By this we see, that the clouds formed on the Ghauts,
charged with water and electricity (by causes I am not now
to investigate), are drawn to the westward, whilst the heat
which, during the formation of these clouds, must neces-
sarily be discharged, is carried to the east or to the lower
parts of the coast, and causes the properties for which the
land winds are so remarkable.

I have acknowledged already, that the heat occasioned
by the power of the sun in this season, contributes to the
aggregate of it in the wind; but I must observe also, that
it acts only as a secondary cause, and passively, by pre-
venting its absorption and diminution in the career over a
variety of substances, particularly moisture* with which it
would combine, if they had not been previously removed
or incapacitated.

In colder climates, this absorption takes place in a greater
degree, as substances are abundant with which the heat
produced by the formation of rain can combine and be-
come imperceptible*. It is, however, there also often m*
marked, that the heat of the sun in a cloudy day is more
powerful than at any other time. In common this is
ascribed to the reflection of the rays of the sun from the
clouds ; but I opine it is often the consequence of the for-
mation of water in the clouds_, which obscure the sky at
that moment.

It has been observed, that the heat of the land winds is
not felt on the top of high hills, or on plains of a very in-
considerable perpendicular height above those in which it
rages most violently ; as for example, in Mysore near the
Ghauts, which is only about five hundred feet higher than
the valleys immediately below. This might be considered a
weighty objection against my theory ; as heat, considered
in the light of an elastic fluid, expands equally on all sides;
and from whatever cause it proceeds, it should be supposed
to extend even further where it meets with less resistance,
as from the air in higher regions, which is known to be
lighter and more penetrable than near the earth.

"But the reverse takes place; for almost immediately
above the clouds no other heat is perceptible than what
might be owing to the nature of the climate.

This circumstance may be accounted for by the dimi-
nished density of the air in the lower parts of the country,

* Carl Dundonald's Treatise, p. CO. " The frequent changes in the de-
gree of heat arid cold in the atmosphere are to he aserihed more to the alter-
nate disengagement and fixation of heat by chemical combination, than to
the effect! of the solar raya."

produced

Hints respecting a New Theory on t he 0 tilts of Comets. 233

produced by the heat of the season, which would naturally
cause the wind to rush thither, with all its contents, and
with greater impetuosity. The coolness of the atmosphere
on elevated situations may be ascribed also to the evapora-
tion of the uppermost strata of the clouds, which accom*
panv the land winds.

Many arguments I have dispensed with, which might
have been produced to elucidate and to establish my theory,
as they were chiefly such as could be collected from simple
inference, and from affirmative application of doctrines ad-
vanced before.

I will only add, that both the sirocco and samiel may be
owing to similar causes as those which appear to be pro-
ductive of the pernicious, or rather disagreeable", effects of
our land winds.

XLVIIF. Hints respecting a Ne?v Theory on the Orbits of
Comets. By Mr. W. Crane, of Edinburgh.

To Mr. Tilloch.

Sir, J. he following theory, for any thing I know, h
original: should it be deemed worthy of a place in the
Philosophical Magazine, its insertiou will much oblige

Your humble servant,
W. Crane,

Sept. 27, 1810. Student of Medicine, Edinburgh.

** K:ist thou ne'er seen the comet Ts flaming flight ?
The illustrious stranger passing, doubles wide
Heaven's mighty cape, and then revisits Earth." — Yoinier.

The difficulties with which this intricate branch of astro-
nomy is surrounded, the short part of an orbit of a comet
that is visible to us, and the rarity of their appearance, have
given rise to innumerable theories, many of which have* no
sooner been advanced than they were immediately abau-
doned as erroneous.

The school of Peripatetics assigned comets no place in
our planetary system, they only considered them as sub-
lunary things made up of the exhalations in the terrestrial
regions; which was the opinion of many, until Tycho Brahe
and Kepler proved by observation that they were beyond the
moon, and consequently not composed of terrestrial va-
pours : this was further confirmed by the observations made
by Cassini, of that seen in the year 1665, and of another
that appeared in April 1CS0. Cartesius thought them to
jhe permanent bodies, like the planets, and to be constantly

carried

254 flints respecting a New Theory

carried from one vortex to another in right lines: but
Cassini supposed from his observations that they moved in
circles very eccentric, and containing the earth's orbit within
them ; and from hence was led to think the comet of 1680
and 1681 was the same as appeared in 1577. By means
of this and some others he had an opportunity of seeing,
he determined that comets moved through the constella-
tions Antinous, Pegasus, Andromeda, Taurus, Centaur,
Scorpio, and the bow of Sagittarius, which he called the
zodiac of comets. That this is not the case, later observa-
tions have proved. The comet that appeared in September
1808 was first seen in Serpentarius, it then passed through
the right shoulder of Hercules, the Lyre, and disappeared ill
the tail of the Swan, which is a course widely different from
the zodiac laid down by Cassini. James Bernouilli, in his
System of Comets, published in 1682, considers them to be
satellites moving about a primary planet, which revolved
around the sun, at a distance equal to 2583 semidiameters
of the Magnus orbis, in four years and 157 days, although
Saturn, who is 258 times nearer, makes only one revolu-
tion in about 30 years. This primary, he says, we can
never see, on account of its smallness and immense di-
stance, and these comets or satellites are only visible when
they descend towards us in perigeum. In this theory we
have a greater body revolving round and carried with a
smaller; which is contrary to what is observed with regard
to the other planets and their satellites. May we not con-
sider this as one of those theories which, had it not come
from so great a man, would have been buried long ago in
oblivion ?

Sir Isaac Newton, Dr. David Gregory, Dr. Ualley, and
others, imagine them to move in very eccentric ellipses,
having the centre of the sun in one of their foci : but some
in their calculations have substituted a portion of a parabola
having the same vertex and focus, which they observe is its
tnte trajectory, if it never returns. This supposition only
leads us from one difficulty to another ; for we may next
ask, By what means did it come within the attraction of
the sun, and from whence ? Are we to suppose it passes
from one fixed star to another in a serpentine direction,
which is the theory adopted by Mr. Cole of Colchester ?
All the celestial phenomena with which we are acquainted,
are obedient to certain laws of attraction, and move either
in circles or ellipses, but none in the manner above men-
tioned.

But to return to the former theory j that is, that they"

move

on the Orhlts of Comets. 25*

move in very eccentric ellipses, in one of the foci of which is
placed our sun ; for, as La Place says in his System of the
World, analogy leads us to imagine that comets move int
orbits, which, instead of being nearly circular, like those of
the other planets, are very eccentric, and the sun extremely
near that part in which they are visible to us; and to observe
the same law as the other planets.

Hence is it not probable that they revolve about two
fixed stars, placed in the two foci of their orbits? This
opinion, I think, is strengthened by the amazing eccen-
tricity of their orbits, which, as was observed above, ap-
proaches very near to a parabola, no comet has yet been seen
that would answer to an hyperbola : of this amazing di-
stance, the exceeding small part we see before a comet ap-
proaches the sun, and when it leaves him, would not differ
much from a right line. Again, as the two foci of the
ellipse in which it moves are so very distant, is it not pro-
bable there are two attracting powers ? that, is one in each
focus"; and as the attraction of one body begins at the point
where the other ends, let us conceive the comet to be put
in motion a little beyond that point, as at Ar and by the
time it arrived at B, its centrifugal C

force becomes great enough to jy r~~~~ * >n

throw it within the attraction Of n^ '+£m ^

the focus D, which we will sup- A

pose at C : it is now acted upon by the attractive power at
D, and acquires in moving from C to D a velocity great
enough to bring it again to A \ and thus it will revolve
about the two fixed stars B D, in a very eccentric ellipse.
This will also account for their appearance from every part
of the heavens: and it is supposed that more than 450 have
been seen in different directions ; for about the same fixed
star many may revolve, yet only one about the same two
fixed stars.

Ferguson, in his Astronomy, estimates the nearest fixed
star at about 32,000,000,000,000 miles distance from the
earth, consequently it is 32,000,082,000,000 miles from
the sun; and Adams, in his Astronomical Essays, says that
the comet seen by Brydone at Palermo in 1770 moved at
the rate of 60,000,000 miles an hour. Now admitting this
to be its average rate, and that it performed a revolution
once in 129 year9, which is the period assigned to that
which appeared in 1 061, we shall have 67,802,400,000,000
miles for the length of its orbit ; and it is not improbable
that this would be the perimeter of an eccentric ellipse
whose foci were the distance above mentioned. . „

256 Machine for securing Persons attempting Depredations

All Nature is held together by an universal bond: the ve-
getable kingdom is joined to the animal by the sensitive
plant; birds and fishes by the bat and beaver; the monkey
joins beast to men ; and the sun by his vast influence hinds
the worlds together that form our system. Let us extend
our views a little further, and we shall have the blazing
comet uniting the systems of other suns to ours, forming
the links of that chain by which the universe is supported.

XLIX. Description of a Machine for securing Persons
attempting Depredations without affecting their Life or
Limbs, By Mr. Robert Salmon, of IVoburn *.

Sir, 1 beg leave to submit to the Society of Arts, &c. a
mantrap, which I hope will meet with their approbation.
To those who live in the country it is needless To explain
the frequency of petty depredations committed on gardens,
orchards, &c. and which are sometimes very vexatious. Few-
persons would like to endanger the life or limb of the de-
predator bv setting the common steel man-trap, yet it is pre-
sumed there are but few who would not wish to detect the
offender. The instrument which I have the honour to sub-
mit to the Society is for the purpose of catching and holding
the person without injury. At the Agricultural Meeting
at Woburn last summer, an ingenious invention for a si-
milar purpose was produced by Sir Theophilus Biddulph; it
consisted of a wood box, containing two springs in iron
barrels, and two chains passingover and round them : when
this was set, the chains were withdrawn from round the
barrels, and extended to a certain distance. A trigger then
kept the trap from closing. The whole was then covered over
with thin iron plates ; so that if a person set his foot on
those plates his leg dropped into the box, and the chains
closed round it and held the leg; but as the box was about
three feet square and a foot deep, it was requisite that it
should at setting be let into the ground, which would be a
work of considerable labour, and when done it would be
difficult to dispose of the stuff from the hole, or to conceal
the trap ; and as the whole apparatus was cumbersome and
expensive, it appeared to me not to be well applicable in
practice.

* From Trans action.', of the Society for the fcncnurageme?it of Arts, Manu-

and Commerce., vol-, xxvii. The silver medal of the Society was

voted to Mr. Salmon for this communication, and one of the machines is
reserved in the Society's repository for the inspection 01 the public.

I think

without affecting their Life or Limls. 257

1 think it right to give this explanation in justice to Sir
Theophilus Biddulph, from whom my idea of the utility of
something of the kind arose, as also to show the difference
-between his invention and the trap I have made, which is
so very simple as hardly to require explanation. When set,
it only requires thai the two keys be withdrawn, and that
the trap be covered with a few loose leaves or mould. To
the trap I have attached a piece of chain and a screw to be
screwed into the ground, so as to prevent its being carried
away ; but against any person that may be caught such a
precaution is perhaps unnecessary, for any person who is
caught will find the jaws of the trap close so fast on the
leg that he caniiot drag the trap far without great pain, and
will consequently be glad to stand still and to call out for
relief. For the convenience of explanation I have applied
mufflers to the jaws of the trap, so that any person may put
ill his leg without the least inconvenience. I have even
tried it without, yet, though void of danger, the sensation
is not pleasant. The muffle will of course be omitted when
set for use, as it is not then necessary to guard against a
little inconvenience, otherwise the springs might be made
weaker. I remain, sir,

Your most obedient humble servant,

Woburn, Feb. 12, 1809. ROBERT SALMON.

to C. Taylor, M.D. Sec.

P. S. — Permit me strongly to recommend to the notice
Of the Society the earth screw attached to the trap, as excel-
lent for the purpose of fixing any thing steadily in the earth.
This screw is far superior to the common way of driving an
iron point or stake therein.

I have employed it for several years in fixing cross- staffs
and other surveying instruments with great advantage. The
very act of driving a spiked instrument into the earth leaves
it loose with some play or movement, which prevents it
from being easily secured ; but with ? screw of this kind at
the bottom or the instrument it is firmly fixed in the ground,
and a turn of the screw will again fix it, if it should by any
means be moved or loosened. It may also be screwed into
the ground with any instrument upon it, which would be
spoiled by the act of driving it in.

Description of Mr. Salmon's Man-Trap, it'hich detains the
Offender^ without injuring or maiming him. See Plate
VIrFig 1.
The principal figure in the fore-ground of Plate VI. is a

Vol, 36. No. 150. Oct. 1810. R perspective

258 Machwe/or securing Depredators.

perspective view of this machine. Fig. 1. ABC is a frame
of wrdught iron, about 18 inches square; it has an eye pro-'
jecting from it to receive a short chain, the other end of
which is fastened to an iron screw, shown separately at D,
screwed into the earth bv the key or handle E: this screw
is about 14 inches long, and, when screwed into hard-
ground, will hold so firmly, that there is no danger of its
being drawn out, even by two or three men ; and having a
small square end, it cannot be turned without the key or
handle E y so that an offender would find it extremely diffi-
cult to remove the trap: eefg are two iron frames moving
on centres in the frame ABC ; these frames have a constant
tendency to close together, by means of two springs pp,
fixed in the frame AB, and acting against pins projecting
from the upright sides of the moveable frame ee ; k k are
two small iron rods jointed to the upper rod of the moveable
frame g, and passing through small locks / /, fixed to the
other frame/'. These locks contain clicks which are pressed
by springs into the teeth, as may be seen upon the rods k kf
so as to prevent the two bars J'g from being drawn asunder
when they have been closed by means of the springs pp.
The internal mechanism of the locks is explained by figures
2, 3, on a larger scale at LM, in the same plate; one side
of the lock is supposed to be removed to exhibit its interior
parts, where k represents the rack, or that part of the rod
•which is cut into teeth, r is the click, which engages the
reeth of the rack, and prevents its being drawn through the
lock : the click is pressed against the teeth of the rack by
a spring, which is plainly seen in the figures; the locks are
attached to the ends of the bar/' of the moveable frame, by
the bar passing through the locks, and when the lids are
riveted on it is confined m such a manner that it cannot
be got out. But as it is necessary to open the bars fg, and
draw the clicks back from the teeth of the racks, Mr. Sal-
mon has contrived two different methods of accomplishing
this object. Figure 3. M is that which is used ill the mo-
del left at the Society's Repository ; a small key or screw S-
is put down through a hole in the lid of the lock, and iy
received into a hole lapped with a screw in the click : bv
turning the screw it lifts the click out of the teeth of the
rack ; so that the moving frames jfg can he opened apart
from each other, till they lie fiat upon the frame AB. The'
iron cross m is then put between the two rods j'g, the screws
S of the two locks are to be withdrawn from the locks, and
the trap is set for use. If an offender should place his foot
within the square of the frame, he would tread down the

crosi'

On the charging Capacity of coated Electrical Jars, 250

fcross m\ and having thus removed the obstruction, the two
frames e efg are closed together by the springs pp> so that
the bars^g inclose his leg, and the clicks in the locks pre-
vent the bars being opened without the screws S. In some
of the machines which Mr. Salmon has made since the
model was deposited with the Society, the locks are made
like figure 2, L, where a common key is to be introduced,
and, when turned round, catches the tail of the click ; it
may have wards to prevent the using of a false key, though
ho wards are shown in the plate. Part of the screw D for
securing the trap from being carried away by depredators,
is shown on a larger scale at N, in order that the peculiar
form of its threads may be better seen, which fix it firmly
in the earth. Such - screws would be very serviceable in
fastening horses at grass, 8cc.

L. An Account of a New Method of increasing the charging
Capacity of coated Electrical Jdrs, discovered by John
Wingfield, Esq. of Shrewsbury *. Communicated by
Mr. John Cuthbertson, Philosophical Instrument-
Maker ', Poland Street, Soho; iv it h some Experiments by
himself on that Subject.

Ls my treatise entitled Practical Electricity and Galvanism,
page 103, I have said that breathing into coated electrical
jars increased their charging capacity to such an astonishing
degree, that their discharge would fuse four times the length,
of wire more than they could in ordinary circumstances ;
which I proved by experiments 147 and 155. Since that
publication, large electrical batteries are become more ge-
neral, and the number of jars increased; so that batteries
containing thirty, sixty, and even a hundred jars are fre-
quently met with; and, when so numerous, breathing inU)
each jar is very disagreeable; and not only that, but in very
dry states of the atmosphere, when most wanted, is even
ineffectual, as those jars first breathed into lose ihat pro-
perty which was produced in them by breathing, before the
last can have obtained it : so that various other means have
been tried ; such as wetting the inside of the jars, and put-
ting wet sponges into them, or by greasing and oiling the
uncoated part in the inside ; all of which gave very uncer-
tain results, till John Wingfield, esq. communicated to me,

* A gentleman who has lately very much, distinguished himself, not only
in the electrical science, but in all other branches of experimental philo-
sophy.

R 8 he

2Co On increasing the charging Capacity

he had discovered, that pasting of paper on the inside and
outside of the jars above the coating, had the effect of pre-
venting the jars from exploding to ihe outside coating, and
believed that their charging capacity would be increased
thereby.

I embraced the first opportunity to try the effect of that
discovery with single jars.

Experiment I. — I took a very thick jar (which had been,
used to show the phenomena of voluntary explosions with-
out breaking) twelve inches high, and the' coating nine
inches, containing in the whole about 17 1 square inches; it
was applied to the conductor of a plate electrical machine,
and six turns of the plate caused a voluntary explosion to
the coating : the state of the atmosphere not being very dry,
it required eight and twelve turns to produce a second and
a third explosion : a fourth could not be produced ; but when
cleaned and dried as before, six turns caused a voluntary
discharge.

Experiment II. — A slip of paper one inch broad was
taken, of sufficient length to fit round the outside of the
jar when the two ends were pasted together : this was slip-
ped on to its outside to about one inch from the coating:'
the uncoated part being rubbed clean and dry, and applied
to the machine, eleven turns of the plate produced a volun-
tary discharge to the outside coaling.

Experiment \U. — The paper ring was then slipped down
to touch the coating, and then applied to the conductor: no-
voluntary discharge could be produced ; and when dis-
charged in the common way, its power did not seem to be
increased, — to prove which,

Erperiment IV.— The common discharging electrome-
ter (which is alwavs fixed to the basement of my machines)
was used, to try to what distance the discharge could be
made to pass from the knob of the conductor to the ball
of the electrometer ; which was found to be one inch and
five-eighths.

.Experiment V.— A piece of iron wire, -j-J-0th part of an
inch in diameter and one inch in length, was hung to the
electrometer, through which a second discharge was made
to pass, and the wire was blued.

Experiment VI. — The paper ring was then taken off and
breathed into twice ; the discharge was then produced at the
distance of two inches, and the wire was fused into balls.

Experiment VIL- — The jar was then rubbed clean and
dry, and a piece of the same sort of wire and the same
length was bling to the electrometer in the same manner

as

i)f ccaied Electrical Jars. ' 261

as before, and it appeared that the greatest charge it could
take had not the least effect upon the wire: thus it appears
that a paper ring so applied docs not increase the charging
capacity of' jars in the same degree as breathing.

Experiment VIII. — The jar was highly charged, and ex-
amined in the dark : the paper ring appeared luminous all
round the uppermost edge.

Experiment IX. — The ring was taken off, and pasted on
in the inside close to the coating : 23 turns caused a volun-
tary explosion through the ring to the outside coating.

Experiment X.— A second ring three quarters of an inch
broad was pasted on close to the other: the same number
of turns produced a voluntary explosion, and the paper was
torn by the discharge, which was repaired and left to dry.

Experiment XI. --When dry, no voluntary explosion
could be obtained.

Experiment XII. — Its greatest power was' then tried, and
was found to be exactly the same as in Experiment V\.{\\ hen
it was breathed into) : it discharged at two inches distance,
and the same length of wire was fused into balls.

Experiment XIII. — A second jar was taken of a larger
size, being 13 inches high, and its coating seven inches;
in the whole it contained about 1 90 square inches: after
being rubbed clean and dry, it was applied to the conductor
of themachirre: twelve turns of the plate produced a volun-
tary explosion to the outside coaring.

Experiment XIV. — A paper ring was put round the un-
coated part on the outside at about 1-|- inch distant from
the coating : eleven turns of the plate produced a voluntary
explosion to the outside coating : the paper ring was then
pushed down to the coating, alter which no voluntary ex-
plosion to the coating could be obtained ; but it discharged
itself to the electrometer ball standing at the distance of Sc-
inches from the knob of the conductor.

Experiment XV. — The same sort of wire, two inches
Jong, as used in Experiment VI, was hung to the electrome-
ter, and the discharge made it blue with several bendings, —
a proof that it had been nearly red hot.

Experiment XVI. — A ring of common writing- paper
one inch broad Avas pasted on the inside close to the coat-
ing, and when dry no voluntary explosion to the coating
could be obtained ; but it discharged itself to the electro-
meter ball standing at the distance of 2-} inches, and the wire
was fused into balls.

Experiment XVII. — The paper rings were now taken off,
and the micoaled part made clean and dry : 19 turns pro-

R 3 dueed

562 On the charging Capacity of coated Electrical Jan.

duced a discbarge to the electrometer ball at the same di-
stance, and the same length of wire was slightly blued.

Experiment XVIII. — The jar was then breathed into*
and a discharge was produced at the same distance, but
the wire was not fused.

Experiment XIX. — The same jar was breathed into a,
second time, and a discharge was caused at the same di-
stance, and the wire was fused into balls exactly the same
as when the paper rings were on.

Experiment XX.— A third jar nine inches high and four
inches diameter, the whole containing about 61 square
inches, when rubbed clean and dry* two turns of the plate
caused a voluntary discharge to the outside coating.

Experiment XXL— A paper ring was pasted on both
sides close to the coating, and one inch from the top, after
which no voluntary explosion could be obtained, but the
electric fluid was seen to run over the brim of the glass to
the outside coating as quick as the machine could give it ;
the discharging distance was seven-eighths of an inch : it
had not power sufficient to make any impression on one
inch of wire.

Experiment XXIT. — The paper rings were then cut nar-
rower at different times, and tried, which increased the dis-<
charging distance, when there remained only one quarter of
an inch which seemed to be the most favourable above the
coating: the discharging distance was If inch,, and the
wire was fused, and dispersed in balls.

Experiment XXIII. — The paper rings were taken off, and
the jar carefully breathed into : six turns of the plate caused
a discharge to the electrometer standing at the distance of
\\ inch, and one inch of wire was fused, and dispersed in
balls, equal with the last experiment.

The above experiments are sufficient to prove that paper
rings pasted on to electrical jars in the manner explained,
do hinder voluntary explosions, and increase the charging
capacity of coated jars, in the same degree as breathing into
them.

Further experiments and observations, setting forth the
advantages that electricians are likely to obtain from the
above discovery, will be the subject of a future paper.

LI. Method

t 263 ] ;

JJ.i Method of constructing commodious Houses witfy
Earthen Walls, By Mr, Robert Salmon, of fVoburn*.

Dear Sir, .Having for some years past practised at this
place the art of pise, or constructing walls with earth, and
having in consequence been several times both publicly
and privately called on to communicate my observations
thereon, I have been led to consider that the best mode of
generally communicating what I know on the subject would
be through the medium of the Society of Arts, &q. I have
accordingly, by the waggon, forwarded a case containing a
model of my frames and apparatus for performing the work,
with every particular in my power to give, for the infor-
mation of any persons inclined to build in that way, and
they will, I hope, be found worthy a place in the collection
of the Societv.

To such as may be inclined to see specimens of this work,
and may not have an opportunity of going far distant from
London, I can recommend a house and other works built,
and some of them inhabited by my brother, Mr. William
Salmon, Builder, at Henley-Hill, near Barnet, Herts.
I have the honour to be,
The Society's and your most obedient servant,

Woburn Park, Dec. 8th, 1808. Kc-BERT SALMON.

To C. Taylor, M. D. Sec.

Description of the Engraving of Mr. Salmon9 s Method of
building Pise or Earthen Walls.

Fig. 4. of* Plate VI. is a perspective view of the apparatus
or moulds, in which the earths are rammed to form a wall.
The mould consists of two long planks Ff, twelve foet long,
twenty inches broad, and one inch thick, each made in two
breadths ; they are strengthened by several pieces of wood
nailed across them. Holes are made through these pieces
of wood at top and bottom, to receive iron bolts, which
hold the two boards parallel to each other, fourteen or six-
teen inches asunder, which is the thickness of the wall in-
tended to be formed between them. The bolts have a large
head at one end, and a key passes through. the other, to
keep the planks together. When a wall is to be built, the
foundation is laid in. brickwork, which is carried about nine

* From Transactions of the Society for the Encouragement of Arts, Mavvfac-
lures, and Commerce, vol. xxvii. — —The Society voted twenty guineas to
Mr. Salmon for this communication, and models of the apparatus arfe re-
served in their Repository tor public inspection.

R 4 inches

264 Method of constructing

inches above the ground ; upon this brickwork the planks
are placed, and bolted together. Two boards, like that
shown at G, are placed between the planks at the ends, to
form the ends of the mould; these boards are placed between
the two bolts a a, which are seen close together at the end
of the moulds, and are held fast by that means; the earth
is now to be rammed in between the moulds by the rammer
with an iron head X. When the mould is filled with earth
and well rammed down, the keys are to he taken out of the
bolts, and the bolts drawn out ; the planks are then removed,
and put together again, a length further upon the wall, the
bolts at the end being put through the holes left in the wall,
only one of the end boards is now put in, and the ramming
proceeds as before : in this manner straight walls may be
built of any length; and when the lower course is finished,
then the mould may be taken to pieces, and put together
again upon that course, the lower bolts of the frame being
put through the bolt holes which the upper bolts made in
the wall at the first operation, to insure that the upper part
of the wall is in the same place, and exactly over the lower.
When a wall is to be built thinner than usual, a block of
wood must be placed under the head of each bolt, so as to
diminish the space between the planks.

When the angle walls of buildings are to be made, the
apparatus is put together, as shown in the plate; four of the
planks are put together to form a right-angled mould, one
end of each of the planks F and H is furnished with double
bolts, the other ends have'each twoeyebolts fixed into them,
as shown separately at bd; then a bolt n connects the two
moulds, so as to form a hinge ; the planks are kept together,
so as to be perpendicular to each other, by a long iron rod
K, hooked into eyeboits fixed in the planks. The outside
planks of the mould are joined together in a different man-
ner, see fig. 5, that of one frame being longer -than that of
the other, and has two pair of holes through its end O, to
receive the bolts / /,' which are fastened to the ends of the
other shorter plank, and the keys are put through the ends
of the bolts, to secure the planks together; a piece of wood
P is occasionally placed between the end of the short plank
and the side of the other, to increase the space between the
planks, to make a thicker wall, the two bolts at the end of
the plank being received into the notches in the piece of
wood, and these bolts are then put through the holes ZZ
of the lon<r plank. Jn building the angle wall, it is neces-
sary that the vertical joint formed between each mould
ehould not be over one another, but arranged in the same

manner

commodious Houses with Earthen Walls. £65

manner as the joints of brickwork : this is accomplished by
making the lower course of wail upon the brickwork only
half the length of the mould, which is clone by placing'the
end board G of the mould in the middle of it. The next,
course over this is to be made the whole length of the mould,
the next one only half, and so on, as shown in the figure.

Improved Moulds and Description of making Earth IFalls,
by Mr. R. Salmon, ofWohurn, Bedfordshire,

The model of the frame in possession of the Society \<&
made to a scale of an inch to a foot, the frame at large is
made of 1^- inch deal, ploughed and tongucd together. The
bolts and pins or keys of iron, as are also the plates on the
holes in the sides of the frame; These plates are put to
prevent the keys from cutting into the wood, and the ho!e$
from gulling and wearing.

This sort of mould is calculated for making walls, either
fourteen or sixteen inches thick, and the model (or perspec-
tive view of it in the distance of Plate VI.) shows how the
mould is to be applied for making the corner of a building
of the sixteen inch wall ; the same moulds may be applied
for a fourteen inch wall, ffbt'ing the outer sides. FH the
inner sides. When employed for straight walls, or making
good between the corners of buildings, the two returns of
the frames are used in pairs, ff and FH make two sets of
frames. "The board marked G must be of width equal to
the thickness of walls to be made, and are for the purpose
of stopping the earth, and making ends or jaumbs to doors
or windows, or wherever wanted. The piece of wood P is
two inches thick, and is for the purpose of making out the
external sides of the moulds, from a fourteen inch to a six-
teen inch wall : by introducing this piece between the two
sidesyy, and putting the fixed iron pins in the outer holes
Z Z, and taking away the blocks under the heads of the
outer bolts, the sides of the frame will then be sixteen inches,
as under, and thereby adapted for a sixteen inch wall. Fio-. tj|
are pieces of wood about 1 J- inch square, and cut to the
length of the thickness of the wall, and are for gauges to
be applied on top of the bolt, to keep the keys from draw-
ing the sides too close together.

In beginning the wall, some of them are necessary at the
bottom, the more firmly to support the frame on the brick
or stone work. They .are then worked into the wall, and,
after the frame is taken down, drove out. Alter the first
course, they are only necessary to the top irons, aud may
J)c taken out as soon as the earth is rammed up near them,

SQ

•

266 Method of constructing

fco that no holes are left in the upper courses of the wall,
more than the bolt holes.

When these frames are used, one side is placed in such a
direction, that the front or end may be required to be taken
away, and then by means of the angular iron brace K, the
other return is sure to stand at right angles with the first.
Care should then be taken, in the first course, to set the
sides level : that being done, the other upper courses, from
the nature of the frames, and manner of using them, must
of course come upright and level without any particular
care,and a wall being properly begun, cannot well gel wrong.
After the first course of a building is done, the moulds
should be moved to another, and so on till all the courses
are up; and as the top holes of each preceding course be-
come the bottom holes in the succeeding ones, no difficulty
will be found in fixing the mould after the first course is
properly done.

Fig. 6. shows the iron pin and staples that keep the in-
ternal angle of the frame together. K, fig. 4. an iron stay
to set the returns at right angles. This is only wanted
where other means of setting the building square are not to
be obtained.

Having described the frame, and means of applying it
generally, it may be necessary to observe the following par-
ticulars in the process.- Having carried one course round
the building, it frequently happens that the top thereof be-
comes too dry to attach to the next succeeding course, and
therefore it is adviseable that, as soon as the frame is set for
the succeeding course, a small quantity of thick grout, com-
posed of ~ lime, and ± earth, be poured on top of each
course, immediately before the first layer of earth is put in.
A very small quantity is sufficient, and will add much to
the strength of the work, by cementing the courses well
together at the joints. The workman should also, with
the corner of hjs rammer, in ramming home to the upright
joints, cut down a little of that part of the wall, up to which
he works; this will make the upright joints key together,
and unite in a solid manner. Having thus proceeded and
got up the walls, the next thing will be to stop the bolt
holes, with mortar made \ jime and -f- earth the same as the
wall.

The earth proper for this work should be neither sand nor
clay, but partaking of both. Clay is particularly objection-
able, as is also chalk, or calcareous earth of any sort. Sand
is also not proper, unless accompanied with some binding
quality : the bolder and coarser the sort of earth the better.

When

commodious Houses with Earthen Walls, 26f

When used, it should retain no more moisture than just to
make it adhere together, under the pressure of the thumb
jand finger. Notwithstanding earths bordering on sand ap-
pear to make the strongest work, nevertheless good earths
may often be found in parts that do not abound with sand.
Those that abound with a mixture of grit or fine gravel are
generally the best. Having provided proper earth, as much
should be put in each layer as to form about an vnch and a
Jialf when compressed bv ramming.

The rammer X should not be more than half an inch
wide on the edge, in order that it may more forcibly com-
press every part of the earth, which a flat rammer would
not do so well.

Tn making the walls, about three inches in thickness
of loose earth should be put in each course, which done,
the same, by means of a trowel made for the purpose, is
drawn back and cleared from the face of the wall, and the
space then filled up with the facing composition, forming
on an average about one inch in thickness ; the whole then
is firmly rammed, (in which, and properly preparing the
facing stuff, much depends the perfection of the work) till
it is quite hard, when it will be compressed to about pne
inch and a half in thickness. The common facing stuff is
composed of lime one part, and earth, the same sort as used
for walling, three parts. The lime and earth mixed and
slacked together, the same as for mortar. The more it is
slacked and wetted the better, provided time can be allowed
for it again to dry and pulverize, so as to be fit for ramming.
The better sort of facing stutf may have a small quantity
more of lime in it.

The foundation should be of brick or stone, carried up
nine inches above the ground ; and if a plinth is to be shown,
then one course above the same should be of brick or stone,
to prevent the water that might lodge on the plinth from
damaging the earth wall.

The proper season for performing this work is any time
that the earth is to be procured sufficiently dry for the pur-
pose; the more early in the season the better, in order to
give it time to dry before finishing, or if late it would be ad-
viseable not to finish till the year after it is built.

Windows and doors may be left in the walls wherever
wanted, by fixing the head of the moulds and carrying up
quoins to form the same: in erecting which some bond tim-
ber should be laid in coarse moi tar and rammed in with the
earth. Lintels may also be laid at the proper height. This
intthod ig cheapest, where only one window or door of a

size

265 Method of constructing

size is wanted ; but if many, the readiest way would be to
make some rough frames of boards of width equal to thick-
ness of walls, and place them in the situation ol the windows
and doors. When done, the earth is rammed up to them,
laying bond timber at the sides and lintels over them. In
both cases the windows and door-frames are to be put in
their places and fastened to the bond -timber, after the wall
is up. The bond timber, lintel, and plates, should be kept
as thin as possible, in order to prevent any disagreement be-
tween the earth and timber in the shrinking or drying; of
the same. The bond timber about 4 inches by l-i-; floor or
wall plates 6 inches by 2; lintels about 4 inches thick ; and
it may be worthy of notice that any slabs or rough stuff may
be used, the earth being sure to ram close to it and keep it
in place.

For common cottages, when the whole of the walls are
up and covered in, the holes should- be stopped with very
coarse mortar made the same as the facing stuff, but used
wetter, and the wall then lime-washed over with lime and
sharp sand, which should be made up in small quantities
and used while hot. This may readily be done by adding a
knob of lime and sand a little at a time as it is used.

For better kind of cottages the better sort of facing stuff
may be used, and then, as before, the whole lime-whited;
cr if it be required to* make the finishing as perfect as pos-
sible, the following is the best" mode, viz. with water and a
brush thoroughly wet and soak the face of the wall for two
or three yards in stiperfjcie at a time; all which part, during
the said wetting, should be continually rubbed and worked
apout with a hand float, till such time the face is rubbed
smooth and even, by which the facing composition will so
wash upas to become a pleasant regularcolour, theface smooth
and hard when dry, and not liable to scale off as a coat of
plastering would do. This finishing will be still improved
by a small quantity of lime bein£ put in the water used for
soaking the face, and if, after the wall is well soaked and
rubbed, as above mentioned, there be thrown thereon with
a brush some of the lime and sand, (such as used for lime-
whiting,) and that also worked into the face; theface will
then become as perfect; and hard as stucco.

Having explained the frames as constructed by me for
performing earth walling, as also the manner of finishing \XX
I beg leave to lay before the Society some observations on
these, compared with the original French means and man-
ner of performing the same, as described in the first volume
of pommunications to the Board of Agriculture.

The

commodious Houses ivith Earthen Walls, 9 Go

The sides of the frames, as formerly constructed, were
supported on joists or cross pieces of timber, which pieces
were cut into the lop of each course of walling. The sides
were then kept together by upright timbers framed into the
cross pieces or joists, and the tops of the upright pieces
were wristed and held together by ropes going across the
frame from one side to the other. In consequence of this
construction, by experience F found much labour was lost
in cutting the channels to lay the cross pieces in.- These
channels, after the buUdings were up, look labour and ma-
terials to fill them in, and rendered the walls less strong.
Also the difficulty of getting the frame rightly placed every
time it was moved, and the elasticity of the rope across the
top, made the whole very imperfect, so much so that all
work done in that manner was untrue and unsound ; as the
rope, however tight it might be strained, would yield to a
certain degree, The labour of moving was g;reat, and when
the frames were set, the cross ropes and uprights above the
sides were much in the way of the workmen.

On examining the model I have the honour to send, it
may be seen that these frames being once set true, they re-
quire very little care afterwards : being kept together by
iron bolts, no elasticity can occur, and the earth will be as
firmly compressed as if rammed between two walls. No
cutting away for cross pieces is required, nor any holes but
the small bolt holes to make good ; and as nothing slicks up
above the frames, the workman cannot be impeded. In
consequence of these alterations the work may be more
cheaply and truly executed than with the old sort of frame.
Previously to entering into the expense of this sort of
work, on my conceptions as to its advantage, it may be ne-
cessary briefly to state from whence such is collected.

About sixteen or eighteen years ago, the late Duke of
Bedford directed a foreigner, who was then making some
walls in Lancashire, lo come and make some specimens
here, and wishing to know how far it might be usefully in-
troduced, T was directed to give attention and every aid to
the man employed. Accordingly frames of the old sort
were made, exactly like those' before described, and with
them some specimens being made, the man returned. These
specimens I considered were very bad walling, and in at-
tending to the execution thereof, seeing sufficient room for
improvement, I was directed further to practise it. Frames
were then constructed like the model, and several walls
erected, among which were some cottages now standing,

and.

$70 Method of constructing Houses with Earthen Watli*

and lastly, thfe house I now live in. This has been builf-
about twelVe years, and is a sufficient proof of the utility of
the practice: the house being as close, warm, and dry in
the walls, as" if built of any materials whatever.

With regard to the expense of the walls of this sort, as
labour is the principal part of the expense, and as in some
places labour is dearer than in others, the best mode of esti-
mating it at different places will be from the quantify that a
man should do in a day, and which I have found* to be \\
yard superficial, in the common day's labour of ten hours.
At this piace the expense may be estimated as follows :

£. s. d.
Labour to making facing composition, fitting in
and ramming to a 1 6-inch wall, where the earth
is at hand (labourer's being is. lod. per day)

per yard superficial . . * . . 0 2 2f '

Value of lime used in the composition rammed
into the face of a yard superficial (lime being

8c?. per bushel) 0 0 3

Lime and labour to rubbing up and finishing the

outside face' of the wall . . . ♦ < o 0 3

Total finished and faced on one side 0 2 8

If a wall to a garden or otherwise, and finished and

faced on both sides* then add 0 0 8

*• I,, .,

Total for walls finished on both sides 0 3 4

At this place the value of a yard of brick-work is more
than ten shillings, of walling only 14 inches thick, the
bracks being 425. per 1000; and lime 8d. per bushel ; con-
sequently tlje economy of the pise must appear; and the
same difference will be found in any other place where lime
and bricks bear the same price, and proper earth can be
found at hand. But as attempting this sort of work, where
it is not applicable, or improperly doing it so as to lead to
failure, mav prevent its introduction where it would be use-
ful, I shall endeavour to point out any precautions that
have struck me, and every thing that has appeared to make
against it.

Many persons have supposed, and it has been asserted,
that almost any earth will do: but such is certainly very er-
Toneous ; for proper earth cannot in all places be found ; and
it being difficult to describe it, or to be sure when it is
found, it seems adviseable, before the entering on any con-

siderablef

Alterations in the Light of the Sun* 271

siderable work, that the experimentalist should first do a
small piece, and let it stand with the top only covered for a,
winter at least.

It has before been observed that the excellence of the
work depends on its having due compression, as well as be-
ing of proper soil. If the compression be not perfect, aU
though the soil be good, the walls will be unsound; and
unfortunately it so happens, that when a wall is built and
badly rammed, its imperfection cannot readily be observed,
and further, the defect is likely only to be found but by
its failure : and hence arises the greatest bar to its general
introduction ; for, as it requires considerable labour to build
a wall, it requires exertion to do it in proper season ; and if
the labourer be employed to do the work by task, it be-
comes his interest to get on and do it slightly, and if done
by day, it will not advance so rapidly : consequently, in
either way, it will require great attention from a careful1
overlooker.

From the foregoing comparative statement of pise against
brickwork, persons unacquainted with building are inclined
to suppose that the whole expense of the building will be in
proportion thereto : contrary to this, it only affects the wall-
ing,— the roof, floor, &c. remaining the same as before,
excepting as it may reduce the quantity of bond timber and
lime used in plastering the inside ; this latter is less than
when plastered on brickwork, the face of the wall being so
much truer than brickwork.

A working drawing, on a scale of one inch to a foot, is
left with the Society, for the inspection of any person in-
clined to construct the apparatus.

LII. Memoir on the Alterations which the Light of the
Sun undergoes on passing through the Atmosphere. Bif
M. Hassknfratz. Read to the Class of Mathematics*
and Fhijsics of the French Institute, 20th October 1806\*v

J. HE sun presents different colours to our eyes : its disk
appears white, yellow, orange, or red, according to the
purity of the air, the height of the orb in the horizon, the
latitude of the places where we observe it, and their eleva-
tion above the level of the sea.

In the torrid zone, the disk of the sun is always white, when
the air is pure, and when it is at the zenith of the place.

In the irigid zone, the disk of the rising or setting sun is
always red in the shortest days of the year..

* Annates de Chiinie, tome btvi. p. 54./

On

2*2 Alterations ivliich the Light of the Sun undergoes

On high mountains, at an equal height above the hori-
zon, the disk of the sun is constantly seen whiter than iflf
valleys and plains.

In general, the white, yellow, orange, or red colour of
the disk depends (if the purity of the air be the same) on
the thickness of the strata of air which the ray passes
through before reaching the eye of the spectator: the thin-
ner the strata which are passed through, the whiter is the
disk: aud vice versa ; the disk being at first yellow, then
orange, and afterwards red. When the air is filled with
exhalations, when it contains solid or liquid substances in
suspension, and when its purity is thereby affected, the disk
of the sun is sometimes coloured ; but more frequently the
intensity of its light diminishes, and the disk remains
white*.'

The cause of the colouring of the sun's disk is one of
those problems which ought to occupy the attention of
philosopher*, and which Interests them the more in propor-
tion to its influence in the phenomena of optics.

It has been strongly asserted, that this effect was caused
bv rays subtracted from the fasciculus during its passage
through the air; but we are entirely ignorant what is the
number and species of the molecules subtracted. Each of
the colours of the disk may result from the separation of
one or more coloured molecules : the only condition that
ought to be fulfilled, is, that the colours engendered by the
subtracted rays should be complementary to those which
are perceived.

The azure colour in which the sky appears to our eyesy
has induced some persons to suppose that it was by the
subtraction of some blue molecules reflected by the air
that the colour of the disk was produced: others have
thought that the purple, violet, blue and green rays, being
more refrangible and more reflexible than the others, were
separated from them in passing through the atmosphere;
and that me red, orange and yellow rays combined with
them, which had not been reflected, occasioned by their
junction the colour of the disk : finally, others have pre-
sumed that the violet and green molecule? were reflected
by the air at the same time that the red molecules and some
green molecules were refracted.

Although the colour of the sun's disk seemed to an-
nounce an action of the air on the coloured molecules ; and*

* Hist.tfe I ' 'Acad. des Sciences, 1721. De. Maifan relates an observation,
of the sun having appeared the whole day through vapours. Its disk wai*
white, and its lustre as usual, but without any rays.

although

on passing through the Atmosphere. 273

although it ought to be presumed that the solar spectrum
should undergo variations flowing from this action; as
no astronomer, to my knowledge, has announced, that it!
the experiments which have been repeated at various times,
and in different places, variations have heen observed in the
colour of the spectrum, and as all are silent as to a phseno-
menon so singular ; it might be supposed that the cause of
the colouring of the disk depended on an order of alteration
with which the spectrum was not affected.

Those hypotheses which attribute to the molecules of air
properties so different were presented under an aspect more
or less seducing; all of them could be discussed, defended,
and adopted, if the reasonings and authorities of authors
had been sufficient : but as none of those who have proposed
them have supported them by any positive facts, I appeal
to experience.

The most natural experiment, and that which every author
ought to make before proposing his hypothesis, is the ana-
lysis of the rays of light when the disk of the sun is present-
ed under colours so various. This analysis has been effected,
and I now present the results to the class.

I fixed upon some fine days in the summer of 1799, when
the sky was pure and the disk of the sun white, which al-
ways happens towards noon, when the sun is at its greatest
elevation.

With this view T introduced a solar ray into a dark room
through an aperture of the size of 25 decimillimeti^s : I
received it on the surface of a prism, which I turned so as
to make the angles formed by the ray refracted, and the
two faces of the prism equal. I observed at one and the
same time both the series of the colours of the spectrum
and its length at 30 decimetres distance from the prism.
I remarked that all the colours were perfectly distinguished
from the purple to the red, and that on the evening of the
same day, at sunset, when its disk appeared yellow, the
spectrums formed by the solar rays were not so long : the
purple no longer existed, and a greater or less portion of
the violet was wanting, and sometimes it was even entirely
wanting.

The experiments thusmade at noon and evening were re*
commenced m the fine weather of the following years, and
gave the same result.

I have the honour to present to the class three spectrums
obtained with the same prism on the 13th of January 1801.
They are remarkable for their length, and for the colours
which i'ovm them. At half past ten o'clock A.M., the
spcclrum, fig. 1, (Plate VII.) was 145 millimetre* long;

Vol. 36. No. 150. Oct. J 810. S at

274 Alterations in the Light of the Sun.

at noon, fig. 2, 185; at four o'clock P. M., fig. 3, 110; ana
ut ten minutes past four, fig. 4, 100.

When the spectrum was longest, the yellow interposed
between the green and the orange was pure; when the
violet disappeared, the yellow assumed a deeper tinge : it
was coloured red, and partook of the orange colour.

I repealed these observations several times, at various
times of the year, and always with the same success; the
spectrum increased or diminished in length according as
the colour of the disk was whiter or yellower.

Finally, on the 15th of January 1605, I remarked, on
observing the decomposition of the light of the setting sun,
that when the disk of that orb was of a fine red, the length
of the spectrum was diminished more than one half: it
was no more than 70 millimetres long; whereas at mid-
day it was 1S5 ; and in the series of colours separated by the
prism, we could only distinguish the red, orange, and green.

M. Gerard, draftsman to the polytechnic school, having
been present on the above occasion, drew and coloured the
solar spectrum in question. Figure 5 is the copy of the
drawing, and fig. 6 presents the image of the sun when it
was received on a white card in the dark room : this tint is
deep orange, approaching the blush of dawn.

The subtraction of one or several coloured rays in the
fasciculus which the sun sends us, when its disk is yellow,
orange, or red, may be easily remarked in the irises observed
at different hours of the day, either in the series of colours
which they present, or in the breadth of the coloured arcs.
I have several times verified this fact since my experiment
in 1802; an experiment which, I must confess, then
seemed to be very important. I have even remarked in the
sky, when the disk of the sun was red, irises which con-
tained only red, orange, and green, like the figure of the
spectrum which I have presented to the class.

From these facts we may conclude, that among the causes
which may produce the alterations observed in the colour oi
the sun's disk, one of the most important is the subtrac-
tion of the coloured rays intercepted by the medium which
they pass through ; and the coloured' molecules separated
from the fasciculus of white light are, the purples and a
part of the violets, when the disk appears yellow: the pur-
ples, the violets, the yellows, and a part of the indigo blues,
when the disk appears orange : the purples, the violets, the
indigo blues, the blues, the yellows, and a Utile of the
orange, when the disk appears red : finally, that there may
be a arm, a colouring of the disk in red, undir the polar
circle, at which all the coloured molecules, at least the red,

are

application of Barometer for indicating the Weather, 275

are subtracted by the air, and that in this case the spectra
and the irises ought to present a single colour only, which
is the red.

LI 1 1. On the Application of the Barometer for indicating
the Weather , and for measuring of Heights in the AtmO"
sphere. By Richard Walker, Esq,

To Mr, Tilloch,

Sir, In order to prognosticate the weather by means of the
barometer, one general rule should be premised, viz. that, pre-
viously to observing the barometer, the state of the weather
at the time should be accurately noticed in every particular.
Hence, to speak figuratively, we might affix this motto to
the barometer, " Tell me what the weather is, and I will
tell you what it will be."

The circumstances to be collected previously to inspect-
ing the barometer are, 1st, The state of the atmosphere,
respecting its degree of clearness or cloudiness : 2dly, The
direction of the wind, together with its steadiness or varia-
bleness: and 3dly, The altitude and density of the clouds.

Signs of Fair Weather,

1. The barometer rising may be considered as a general
indication that the weather, comparatively with the state of
it at the time of observation, is becoming clearer.

2. The atmosphere apparently becoming clearer, and the
barometer above rain, and rising, show a disposition in the
air for fair weather.*

3. The atmosphere becoming clear, and the barometer
above changeable, and rising, indicate fair weather.

4. The atmosphere clear, and the barometer near fair,
and rising, denote continued fair weather.

5. Our prognostic of the weather is to be guided, rela-
tively, thus : If, notwithstanding the sinking of the baro-
meter, little or no rain follow, and it afterwards rise, we
may expect continued dry weather.

6. If, during a series of cloudy rainy weather, the baro-
meter rise gradually, though yet below rain, especially if
the wind change from the south or west towards the north
or east points, clear and dry weather mav be expected.

7. The weather for a short period, viz. from morning
until evening, may commonly be foretold with a considera-
ble degree of certainty. If the barometer has risen during
the night and is still rising, the clouds are high and ap-
parently dispersing, and the wind calm, especially if it be
in or about the north or east points, a dry day may be con-

S 2 fidently

276 Application of Barometer for indicating the Weather,

fidently expected : — the same rule applies for predicting the
weather from evening till morning.

8. During the increase of the moon there seems to be
a greater disposition or effort in the air for clear dry weather
than in the wain,: but this disposition does not usually
commence till about three or four days alter the new moon,
and ceases about three or four days after the full moon.

9. The barometer should be observed occasionally thrice
in the day, or oftener when the weather is changeable, in
order to notice whether the mercury be stationary, rising,
or sinking; for from this circumstance, together with the
direction of the wind and the apparent state of the air at the
time, is information to be collected, and a continuance of the
same, or a sudden change of the weather, to be foreseen*.

10. Lastly, Observe always — The higher the mercury
shall stand in the scale in each instance, and the more re-
gularly progressive its motion shall be, the stronger will be
the indication : likewise, The more the wind inclines towards
the north or east points, the greater will be the disposition
in the air for fair weather.

The indications of rainy lueather will obviously be the
direct reverse of those rules which predict fair weather.

Frost is indicated in winter by the same rules that in-
dicate fair weather, the wind being in or about the north
or east points, and the thermometer sinking towards 32.

A fall of snow seldom comes without a previous frost of
come duration, and is indicated by the sinking of the baro-
meter, especially if the mercury be below changeable,
and the thermometer at or near the freezing point.

When the temperature of the air is about 35°, snow and
rain sometimes fall together; at a warmer temperature than
35° it seldom snows, or rains at a colder temperature.

Thunder is presaged by the same rules which indicate rain,
accompanied bv sultry heat ; the thermometer being up to 75.

Storms, hurricanes, and high winds, are indicated by the
barometer falling suddenly, or sinking considerably below

MVCll KAIX.

The barometer is known to be rising or sinking by the
mercury having either a convex or concave surface, or by
the perceptible rise or descent of the mercury if at the time
of observation the barometer be gently rapped f.

if at any time the weather should differ widely from the

* A barometer, conveniently portable, merely for the purpose of ascer-
taining whether1 the atmosphere U beconrng denser or rarer, is a great desi-
derafum, hut, 1 should apprehend, not very easy to be constructed.

f The best index for these observations is a plate of metal extending as
far as the middle of the column of mercury iu the barometer, having a
0<*ff4f><g line acres.; [I s ceatre of the plate.

indications

and for measuring Heights in the Atmosphere. <2~7

indications of the barometer, it maybe presumed, as is
sometimes known to happen, that a particular spot is af-
fected by local circumstances.

After a long continued series of wet weather, wc may,
when the weather becomes fine, expect an uninterrupted
continuance of dry weather.

• If, after a long series of wet weather, the barometer rise
above changeable, and the wind veer steady to the north
or east points, a continued duration of fair weather may
be expected.

Slow and progressive variations in the barometer, with a
fixed and steady state of the wind, indicate permanency with
the chancre.

The barometer standing at or above fair, denotes ge-
nerally fair weather, although the atmosphere wear at the
time an unfavourable aspect.

Lastly, The greater coincidence there is of the circum-
stances enumerated in the rules above mentioned, the
stronger may our confidence be in the expectation of fair
weather, and in the continuance of it when present, by the
barometer whilst high, remaining stationary, or varying but
little, and the state of the atmosphere, and direction of the
wind, disposed to be settled.

In this variable climate, there is no reliance, T think, to
be placed on any rules, beyond those above mentioned, for
indicating the weather for any length of time together, or
for any distant period.

Many of these rules, perhaps, may appear trite, and as
if collected from the observations of others; but, uncon-
scious of retaining those of any other person in my mind>
I give these as the result of my own experience.

A Summary Method for ascertaining without the Use of
Logarithms, the various Degrees of Elevation in the At-
mosphere, by means of the Barometer, which, by the Ex-
am pies that follow, will be found to give a tolerably close
Approximation to the geometrical Measurement.

The following Tables are applied thus:
1st. Note down the height of the barometer at the lower
station, in inches, tenths, and hundredths* ; and the tem-
perature of the air, as indicated by the thermometer,

2dly. In a similar manner note down the height of the
barometer at the tippet station; and the temperature of the
air (if this differ from the former observation).

3dly. Subtract the quantity shown by the barometer in the
upper station, from that which is shown in the loner station.

* I have judged it unnecessary to descend below himdredths on the barometer.

S 3 4thlv. Seek

278 Application of Barometer for indicating the Weather 9

4thly Seek in the column of temperatures, Table I., for
the temperature observed at the stations, (or for the mean
of the two, if they differ,) and note down the number of
feet, tenths, and hundredths, which are placed opposite to
that temperature in the adjoining column.

5thly. Make corrections (if requisite) from Table II.

6thly. Multiply the numbers, so found and corrected,
by the difference between the altitudes of the barometer at
the lower and upper stations.

7thlv. Add to the product the increased ratio, from
Table III., which finishes the process.

Table I exhibits the number of feet, tenths, and hun-
dredths, in perpendicular altitude, indicated by the descent
of the mercury in the barometer for each hundredth part
of an inch; which descent varies according to the tem-
perature of the air, at the rate shown in the corresponding
column. This table is constructed on the supposition that
the barometer at the lower station is at 30 inches.

N. B. Although this calculation be given for each hun-
dredth part of an inch of variation on the barometer, it may
be used for variations of one tenth, or of one inch, by merely
altering the denomination of the figures in the column, thus :

Feet. Tenth Hund.

The variation of 100th part of an inch, at temO .

perature 90°, indicates altitude of r' '

Feet. Tenth.

The variation of a 10th part of an inch 99 > 5.

Feet.

The variation of an inch 995.

Table II. shows the alteration which must be made in
the numbers taken from Table I., when the barometer is
not at 30 inches in the lower station. If it be lower than
30 inches, the number of feet, which are placed opposite to
the barometer's height in this table, must be added to the
feet r& altitude corresponding with the descent of the mer-
cury in the barometer for one inch. If it be higher than 30
inches, subtract instead of adding.

N. B. It the variation of the barometer be not so much
as an inch, but only some tenths of an inch, then the
figures in the second column will not represent feet, but
tenths of feet to be added or subtracted.

Table III. shows the number of feet to be ultimately
added to each 100 feet of altitude. This number varies
from 1 to 46 > according as the barometer in the upper sta-
tion stands between the altitudes of 31 and 14 inches.

N. B. A table for the correction, or equation of heat,, in
the barometer, when the temperature of the atmosphere
differs at the upper and lower stations, is provided for here,
by the adjustment of the table of temperatures. T\ble

and for measuring Heights in the Atmosphere. 279
Table I. Table II. Table III.

Altitudes for!

Height of

Increasing Ratio.

the Variation

Barometer.

j^

2 ofevery 100th

5

.5 n ^

~j of an Inch on

5

15

u the Barome-

4)

cu ter.

4

i 12

9

31,0 1

S .^-tt

3

1 9

30,0 1

2

$ 6

29,0 2

90 9,9,5

1

3
0

28,0. ... 3

88 9,9,0

30,0

27,0 4

86 9,8,5

8

3
6

26,0.... 5

84 9,8,0

25,0.... 6

82 9,7,5

7
6

9

12

5 7

80.... 9,7,0

24,0 8

78..., 9,6,5

5
4

15
18

5 9

76.... 9,6,0

23,0 10

74.... 9,5,5

3

21

5 ... .1 1

72.... 9 5,0

2

3j 24

22,0 12

70 . . . .9,4,6

1

' 27 '
30
33
36

7 13

68 9,4/2

66 9,3,8

29,0

9

8

3 14

21,0. ...15

64 . . . .9,3,4

7. ...16

62.... 9,3,0

7
6

39
42

3 17

60 99"296

20,0.... 18

58 9,2,2

56 9,1,8

28,5

45

7 19

3 20

54.... 9,1,4

2 JSi

MB "Si

19,0 21

52.... 9 1,0

1 2

7 . . . .22

50 9,0,6

3 23

48 9,0,2

18,0.. ..24

46 8,9,8

7 25

44.... 8,9,4

5 26

42 8,9,0

3 27

40.... 8,8,6

17,0 28

38.... 8,8,2

8.... 29

36.... 8,7,8

,

6 30

34.... 8,7,4

4 3t

32.... 8, 7,0

2. . . .32

30 6,6,6

16,0 33

8 34

6 35

4 36

2 37

1 ....38

15,0.... 39

*14,0 46

Example

On the top of Chimboraao, one of the Andes in South America, and
S 4 the

280 Application of Barometer for indicating the Weather.
Example I,

Inches.Tenth Hund.

Lower station 29,0,0

Upper station 28,0,0

Difference 1,0,0.

Temperature of air 60° = 926 feet to 1 inch

of variat".

For 29 inches at lower station, add 30 feet from

Table II,

956
Increased ratio, 3 to each 100, Table III = 28

Estimated height . . 984 feet.

Example 2.

Lower station , 30,0,1

Upper station , 29,5,3

Difference 0,4,8.

Ft.Tcnth.

Temperature of air 60° = 92,6 to each 10th

(Lower station 30 inches, no correction) of an inch

Multiply 92,6 feet by 48 tenths . . . . = 444,5, variation.
Add for increasing ratio l£ per 100 .= 6,

Estimated height . . 450,5,

Height by geometrical measure 451,2,

Example 3.

Inches.Tenrn Hund.

Lower station 29,9,7

Upper station f 26,2,8

Difference 3,6,9

Mean temperature of air 54° = 914 feet to each

For 29,9 at lower station add (Table II.) 3 inch of

■ variation.

917

the highest mountain in the world, a barometer would stand nearly as
low as 14 inches, its summit being 20,280 feet above the level of the sea.
The greatest height to be relied on, to which any person has ascended with
a balloon, is that at which the barometer stands at about 24 inches, which
is equal to 6,027 feet; though some are said to have reached 1G3000 feet.

Multiply

Process for the Preparation of Muriate of Mei cury. 28 1

reef. Tenth.

Multiply 91 7 by 3,6,9 = 3333,7

Add, increasing ratio 5 per 100 ... .= 169,

Estimated height . . 3552,7

Height by geometrical measure 3558 feet.

Example 4.

Incher. Tenth Ihmi.

Lower station 29,9,3

Upper station 1 6,8, 1

Difference 13,1,2

Mean temperature of air 64- .......= 934 feet to each

For lower station 29,9 add . , 3 inch of

variation.

93 7

Multiply 937 by 13,1,2 == 12^93,4*

Add increasing ratio 29 per 100. .= 3,565,

Estimated height . . 15,858,4

Height by geometrical measure ..... 1 5,S33 feet.

N. B. In the three last examples, the heights of the ba-
rometer at thedifferent stations, and the geometrical heights
corresponding thereto, are extracted from different works
of unquestionable authority. I am, sir,

Your obedient servant,

Queen-street, Oxford, PiICHARD WALKER.

Oct. 1.",, 1810.

L1V. (Economical Process for the Preparation of the sub-
limed Muriate of Mercury {Calomel)-, to luhick is sub-
joined, an easy Method of purifying the Calomel used in
Commei-ce. By M. Planche *.

Anxious to avoid the inconvenience which results from
the employment of corrosive sublimate in the preparation
of calomel ; convinced by experience that the various me-
thods proposed with this vie^v by Van Tvions and Brugnatelli
were insufficient; and considering the discrepancy which
prevails in most of the pharmacopoeias of Europe, as to the

* Annates de Chimic, tome Ixvi. p. 168.

f82 Process for the Preparation of Muriate of Mercury.

closes of corrosive sublimate, and of metallic mercury, which
ought to be used in this preparation ; M. Planche, after nu-
merous trials, has ascertained that it is sufficient, in order
to obtain calomel, to sublime a mixture of sulphate of mer-
cury at the ininimum, and of dry muriate of soda.

Preparation of the Sulphate of Mercury. Introduce into
a stone retort placed in a reverberating furnace one part of
crude mercury, and one part and a half of sulphuric acid
at 66° of Baume's areometer. Fix an adopter and a tubu-
lated receiver to the retort, which must be made to com-
municate either with distilled water contained in Woulf's
flasks, if we wish to collect the sulphurous acid; or with
the external air, if the situation of the place admit of the
gas being set at liberty. Gradually heat the retort until the
acid boils, and keep up the fire while the acid vapours are
disengaged in abundance, taking care to slacken it towards
the end of the operation, i.e. when the drops of the liquid
which passes from the retort into the bell-glass succeed
each other slowly, and when there is a diminution of the
white vapours. After this operation, which lasts four or five
hours, the retort may be broken ; or, rather, we may sepa-
rate by means of tongs the sulphate of mercury, which is
easily detached.

The acid sulphate of mercury thus obtained is very white
and very friable ; it passes to the yellow colour on the ad-
dition of the most trifling quantity of cold water. In or-
der to carry this salt to the state of sulphate at the minimum,
the author combines it with quicksilver in the following
manner.

He takes 18 parts of the above acid sulphate of mercury,
and eleven parts of mercury. He triturates them together
in a mortar, or in a porcelain capsule, adding by degrees
six parts of cold water.

The first portions of water make the sulphate assume a
yellow colour, which soon disappears on shaking it. Heat
is developed. The matter assumes a very deep gray co-
lour. After a few minutes trituration, he adds a sufficient
quantity of water to give to the whole the consistence of a
thick broth ; and he continues to triturate until the mass
has become of a dirty white, and the mercury has totally
disappeared, which lasis for five or six hours when the mass
is considerable. He afterwards dries this substance in a
stove at a temperature of 30° to 35° of Reaumur.

M. Planche is of opinion, that the mercurial mass which
results from this operation is in the state of sulphate at the
minimum, and he proves it by the following experiments.

1. It

Process for metallizing Potash and Soda. 283

1. It is soluble in distilled water, and its solution does
not alter the tincture of turnsole or the syrup of violets.

2. It is precipitated black by lime water, and gray by
ammonia.

Preparation of the mild Muriate of Mercury. To convert
the sulphate of mercury into calomel, mix intimately, on a
porphyry stone, equal parts in weight of the sulphate of
mercury as above designated at the minimum, and of sea
salt purified and dried : introduce the mixture into matrasses
with flat bottoms two- thirds of which are left empty, and
proceed to sublimation in the usual way. After the opera-
tion, which lasts five or six hours, there will be found in
the arch of the subliming vessel a loaf of calomel of the
weight of about 30 ounces, if four pounds of mixture are
operated upon. This salt is as white as that of commerce,
and purer than that which we commonly meet with as
coming from the laboratories of Switzerland.

In order to add to its purity, particularly when the heat
has not been well managed, the author of the memoir pro-
poses the following method, which perfectly succeeded with
jiim, and which has the advantage of having no action on
the mercurial salt.

Purification of Calomel. Pulverize the calomel in a
mortar of marble or of hard stone. Pass it through a fine
hair sieve in order to obtain a homogeneous powder tole-
rably fine. Introduce the pulverized salt into matrasses of
the same form as in the foregoing operation : afterwards
cover it with a' layer about two lines thick of fine sand, pre-
viously washed with water slightly sharpened with muriatic
acid, in order to free it from the carbonate of lime and
oxide of iron which are mixed with it, and sublime as be-
fore directed. The calomel purified by this process is very
pure. M. Planche has presented to the Institution a loaf of
it very regularly crystallized, and in whiteness equal to that
of corrosive sublimate.

LV. Description of a Process hy means of which we may
metallize Potash and Soda without the Assistance of Iron.
By M. Curaudau*.

A he decomposition of the alkalis, which I have never re-
garded as simple bodies, having been long an object of my
inquiries, I became anxious to repeat the experiment ac-
cording to which Messrs. Thenard and Gay Lussac have

• Jitn&les de Chimie^ tome lxvi, p. 97.

announced

£?S4 Process for mela!rrz>ng Potash and Soda.

announced that potash and soda mi^ht be converted into
metal hv means oF iron; but not having obtained results
more satisfactory than those who to my knowledge have
repeated the same experiment, I continued my inquiries,
which appeared to me to he the more likely to be successful,
as Mr. Davy had thrown so much light upon certain phe-
nomena which I had observed, but could not till then ac-
count for.

In short ; if, according to the hypothesis of the celebrated
Kn&jish chemist, potash and soda were metallic oxides, wis
it not more than probable that the prussic calcinations were
nothing else than the combination of this metal with char-
coal ? Such at least was my opinion then, and it will be
seen how far it was well founded, since I succeeded in
metallizing potash and soda, by heating strongly one of
these two alkalis with charcoal ; a process which, as we
shall find, enters into the prussic calcinations.

The metallization of potash and of soda taking place
with one or other of the two mixtures which I have pointed
out, and succeeding equally well in stone retorts as in iron
pipes, we may employ the former or latter process indis-
criminately. As to the nature of the vessel, I prefer an
iron one, because it is more permeable to the caloric, ami
less subject to fuse than stone, particularly when the latter
is penetrated with alkali ; an inconvenience which prevents
us from bringing the operation to an end : which docs not
so frequently happen with the iron.

Firsl Process. Mix exactly four parts of well pulverized
rnimal charcoal with three parts of carbonate of soda dried
in the fire without having been melted : combine the whole
with a sufficient quantity of linseed oil, but so as not to
make a paste.

Stcvvd Process. Take two parts of flour, and mix them
Ultimately with one part of carbonate of soda prepared as
in the foregoing experiment : add to the mixture a sufficient
quaotitv of linseed oil, but so as not to prevent it from be-
ing in a pulverulent state.

Whatever be the kind of vessel emplovcd for calcining
the eub.-tar.ee in question, and whether the^' first or se-
cond mixture be used, we must always begin by heating
gradually: but as soon as the matter is a dull red, we may
increase the fife until we sec in the inside of the retort or
iron pipe a tine celestial blue light, the areola of which js
greenish. To this light there soon succeeds a very abun-
dant vapour, which ouscures the whole inside of the vessel,
and which is the metal extricating itself from the mixture.

The

Process for metallizing Potash and Soda. 2S5

The fire must no longer be increased, for at this tempera-
ture the retort begins to melt; and if the iron resists better,
it is because the alkali penetrates it less speedily than it
does the stone ; and also, because the heat which it re-
ceives is sooner transmitted to the matter.

In order to collect the metal as fast as it is formed, intro-
duce into the vessel a piece of iron well scoured ; and as
we must not give it time to become red, it must be with-
drawn in four or five seconds : it is then entirely covered
with metal, which may be removed by suddenly plunging
the iron into a glass cucurbit tilled with spirits pt turpen-
tine. This cucurbit ought to be dipped in a bucket of
water, in order to prevent the spirits of turpentine from
boiling. Still, however, in spite of this precaution, it is
sometimes so heated as to take fire when the pieces of iron
are introduced into it.

Requisites for the Operation. It requires three persons
to perform the operation well. One must work the bellows,
and take care of the fire: the most expert of the attendants
collects the metal as it is produced, and plunges with the
utmost celerity the pieces of iron into the turpentine: the
third assistant removes the metal which adheres 10 the iron,
and afterwards dips it into the water, as well to cool it as
to remove the alkali which has escaped metallization, and
that which is formed by the combustion of the metal be-
fore its immersion into the turpentine. He takes care also
to clean the pieces of iron well before using them.

This operation requires the most dexterous manipulation
while the metal is forming. The bellows must also be
carefully managed ; for, if the fire be suddenly slackened, the
metal ceases to be set free, and the pieces of iron are covered
with pure alkali only: if, on the other hand, the fire is
hastily increased at this instant, the vessel melts, and the
experiment is fruitless. This proves, therefore, that the
temperature ought to be uniform and steady. I have ob-
served that it is always at the heat of melting iron that
the metal is produced. It rarely happens that an iron pipe
serves twice, and the retorts melt long before the whole
of the metal is obtained which the alkali can produce.

I purpose subsequently to make known any observations
which I may happen to make on this metallic produce: in
the mean time I think I may infer from my experiments,
that the. production of the metal is not owing, as has been
said, to the deoxygenation of the alkali, but is on the con-
traryanew compound, into which hydrogen seems to have

entered.

£86 Reflections on some Mineralogical Systems.

entered in combination, and which in my opinion would
be in a very condensed state in it*.

To conclude : — During the whole operation, hydrogen is
extricated, alkali not metallized, and radical prussic gas. I
have collected this last product in particular in great quan-
tities.

These results tend, therefore, to prove either that hydro-
gen is one of the constituent parts of the alkalis, and the
disengagement of which is favoured by charcoal, or rather
that the charcoal itself is a compound of which hydrogen
is one of the principles. We must choose between one or
other of these hypotheses.

fc .... .,,,,., ji

LVI. Reflections on some Mineralogical Systems. By
R. Chenevix, Esq. F.R.S. and M.R.I.A., &c. Trans-
lated entire from the Frejich, with Notes by the Trans-
lator f.

FUNDAMENTAL PRINCIPLES AND GENERAL EXAMINATION
OF THE WERNERIAN SCHEME.

INature has given to all bodies properties which are either
immediately or mediately sensible. This is the basis of all
systems of mineralogy. One mean of rendering our learn-
ing useful is by establishing unities, to which every thing
may be referred, and which we afterwards adopt either
wholly or in part. We seek a principle the most general
and least variable possible, to employ it as a basis for the
determination of these unities : in natural history, it is
agreed to call the latter by the name of species. In the ve-
getable and animal kingdoms, the faculty of reproducing
individuals fecund and similar to their parents constitutes
a species.

This principle of specification has been received as law-
ful; but it is not applicable to the mineral kingdom. Does
there exist any other? If we consult the ancient works on
mineralogy, we are tempted to believe that it is totally
wanting. In more modern times, M.Werner is engaged in
seeking and noting in minerals every niing that immediately

* The opinion expressed in this paragraph has been since retracted by
the French chemists. — Edit.

f As the learned author has not thought proper to publish these ingenious
and scientific reflections in his native language, a circumstance much to be
regretted, the translator has, for the sake of perspicuity, taken the liberty of
classing them under different heads, according to the subject discussed: he
has also ventured occasionally to introduce in [ ] the real or approximate
synonyms of the various minerals mentioned by the author, in order to
enable the English reader to form more precise notions of the different sub-
«ance6, and feel the force and justice of the author's reasoning. B.

strikes

Reflections on some Mineralogical Systems* 287

strikes the senses; and he has succeeded in uniting the
principles which enable him to class and distinguish mi-
nerals into a body of doctrine. The colour, brilliancy,
fracture, and other properties, have been examined in a
point of view the best calculated to attain this object: the
advantages which a knowledge of the latent qualities may
offer have not been neglected ; — these labours have procured
the author the approbation of the learned world. In this
manner a great step has been made; and if it does not con-
duct us entirely to our object, it at least demonstrates the
difficulty of attaining it. M. Werner has said (Memoir of
Daubuisson, Journal de Physique, Frimaire, 1 6th year), " that
all the minerals which have the same constituent parts,
both with respect to quality and quantity, form only one
species ; and that all those which differ essentially belong to
different species. If, in the same species, "he adds, u divers
minerals having the same characters (one only excepted)
differ from others in two or three characters '(a greater num-
ber would induce a difference of species) from those which
we have designated, they form a particular subspecies.
Finally, When an individual in a species, or subspecies,
presents but one different character, it forms a variety. "

To the word essentially I have two objections. In the
first place, it does not excite the same idea in all minds, and
we can have no precise notion respecting it, while it has no
fixed signification. In the second place, the chemical means
which could enable us to pronounce with some certainty
on what belongs essentially or accidentally to the compo-
sition of a mineral, are entirely omitted. But let us suppose,
fora moment, that we have acquired the necessary knowledge.
The chemical composition is therefore the trzie basis of specifi-
cation in this system*. We also learn from the above quota-
tion, that when two minerals of the same species differ in one

* To this the Wernerians object, that it is degrading to mineralogy to
be dependent on chemistry ; that it is possible for a man to be a very good
mineralogist without being previously a chemist ; and that they are two
djftrat and independent sciences. In support of these positions, they some-
times appeal to the increasing number of botanical nomenclaturists who are
not vegetable physiologists: but the allusion only tends to place mechanism
before science; the former aie to the latter what sculptors and lapidaries are

,to scientific mineralogists. The Wernerians, therefore, when they reject
chemical science, and build solely on their external characters place them-
selves on precisely the same basis as the lapidaries and sculptors; they be-
come artists, but not men of science properly so called. They may indeed
be most acute observers, very accurate reporters of their observations, and
even pioneers in the fields of mineralogical science ; but they ought not to
aspire to be world- makers, or attempt to raise any superstructure without
the aid of chemistry ; while mineralogy and particularly geology are not less

. sciences of deduction than of observation. — Thans.

character,

SSB Reflections oil some Mincratogicat Systems*

character, they are varieties ; if in two or three, they form
subspecies. If the number of dissimilar specific characters
exceed three, the minerals thus characterized must belong
to different species. Here, then, is a second idea of the
species which has just presented itself; and to reconcile it
with the first, we have only to believe that the variation of
more than three specific characters is an inseparable conse-
quence of an essential difference in the chemical composition
of minerals.

We cannot be perfectly sensible why the number three
should be that which characterizes a change in the che-
mical composition, and we are tempted to believe that it
has been taken at random. It is nevertheless founded on
a motive. The species is subdivided into subspecies and
variety ; the variety, therefore, is the last subdivision of
the species ; and to determine the last subdivision but one,
the variation of two or of three has been chosen. It is,
therefore, necessary to carry beyond three the difference of
species ; that is to sav, (according to the passage already
quoted,) the essential difference in the chemical composition.
1 have said that there was a very good motive for choosing
the number three; but I have not said that it was suscepti-
ble of being acknowledged by nature.

In establishing the difference of species solely on the dif-
ference of any determinate number of specific characters,
we render it independent of every consideration either of
the value of the characters, or of the extent in which the
shades of these characters differ. In this hypothesis if.
matters not, that two minerals have two or even three cha-
racters so different that they form, if we may so speak, the
extremes of the series of characteristic analogies: if we can-
not discover a fourth which is also different, these two mi-
nerals must belong to the same species : or let any number
whatever of minerals that I can divide into two series form
a difference in three specific characters; let all those of the
first portion be opake, ductile, and so soft as to be cut with
the nail ; let those of the second be transparent, not ductile,
and so hard as to resist the file; let all the other characters
be entirely similar in every respect, still the individuals
which compose these two portions are of the same species,
since the number of different characters does not exceed
three. Moreover, let us suppose all these minerals of a
brownish' red colour, except one only, which maybe a red-
dish brown. Here we must now renounce these principles
in which the single shade between brownish red and reddish
brown, (for M. Werner places them in two different species

among:

"Reflections on some Mirier ah gical Systems, 2S&

among the colours) effects the translation of a mineral from
one species to that of another, as it is that which, super-
added to the first, forms the fourth characteristic difference,
while the other minerals always remain in the same species
as before. — It is the last pound under which the camel suc«
cumbs.

Here is a second example of the very serious incon-
veniences arising from making the species depend on any
fixed number of characters. Form is a character, crystal-
lization is comprehended in forms. M.Werner admits the
prism only where there exist certain proportions between
its height and its breadth ; if we diminish the former, the
prism becomes, a table. The prism and table are considered
as making two different species of primitive forms. Take
a crystal of calcareous spar in a hexahedral prism, and an-
other crystal of the same in a hexahedral table; here is a
different primary specific character in these two specimens
of calcareous spar. Suppose the table very near becoming
a prism, and the prism approaching very near to the table ;
and suppose the one translucid and the other ©pake; add
two specific characters not less insignificant than these two>
and behold a new species at very little expense. But, had
the causes which determine crystallization added some mo-
lecules of carbonate of lime to the calcareous spar, in the
direction of the axis of the prism which was considered a
table, it would have been saved from this forced separation
from its equals.

In establishing a subspecies, if the liberty of choosing two
or three for the number of characters by which the ob-
server decides, leave any influence to the particular value
of each character, it is necessary that this value should rest
on a solid basis ; otherwise we risk the danger of making
arbitrary dispositions, and the same mineral may be found
belonging to as many different species as there will be per-
sons who shall examine it. M. Werner, indeed, has di-
stinguished some characters by the order of importance iii
the determination of the species, as well as in the diagnosis
of minerals. He gives sometimes to the specific gravity,
sometimes to the colour, more value than to the greater part
of the other characters, t have seized every opportunity
to acquire clear ideas on this subject, either in consulting
M. Werner himself, or addressing those who had profited
most by his instructions ; and all that I have been able to
learn amounts only to this, That the value of a character
varies from one species to another : thus, then, to decide
on it, it is necessary to know the species, that is to say, in

Vol. 36. No. 150. Oct. 1810. T algebraic

290 Reflections on some Mineralogkal Systems,

algebraic language, for to find the value of x, we must
commence with knowing it.

AVERNERIAN DIVISION OF THE EXTERNAL CHARACTERS.

M. Werner has divided the external characters into ge-
neric characters, specific characters, and characters of va-
rieties which influence the systematical distribution of mi-
nerals under analogous denominations. The colour, lustre,
and specific gravity undergo subdivisions. White, gray,
black, blue, green, yellow and brown, are species among
the colours. The shades of these characters form subdivi-
sions, and they are pronounced in adding an epithet to the
word which designates the specific character. Thus, cela-
don- or sea-green is a variety of green ; gosling- {serin) green
is another,- sky-blue is a variety of blue, as sulphur-yellow
is one of yellow. These distinctions cannot be mistaken
as soon as we understand to pronounce the attributes of the
specific colour according to the rules. But the difference
between celadon-green and gosling-green is really greater
than between sky-blue and celadon-green, and the same
between gosling-green and sulphur-yellow: that is to say,
the varieties of the same species differ more from each other
than two species differ. This mode of distribution may-
suffice for the nomenclature, but by no means for the thing;
it satisfies the ear, because the ear does not judge of colours.

The division of external characters into specific and ge-
neric characters, and characters of variety, places us in a
new difficulty ; for we here see a third principle of classifica-
tion relative to minerals. We had the number of different
characters, and the value of each character; now we have
the intensity of these same characters. It is also impossible
to see clearly how we ought to form species and varieties
in minerals : if it is by the number solely, we exclude the
importance of characters, and the shades are all of the same
value ; if we concede any thing to the importance, we must
modify the rules respecting the number; and if the character
of variety be sufficient to establish the mineralogical variety,
as but one is wanting, What shall we do when it is a specific
character which differs? How many characters of variety
are equivalent to a specific character ? How many to a gene-
ric ? In all these', too, we must carefully avoid taking the least
possible difference of characters to establish the mineralo-
gical subdivision, which is not itself the smallest.

Unity of principle in a system of classification is that
which tends most to give it precision. If we feel ourselves
obliged to admit several principles, it loses this advantage,

unless

•

Reflections on some Miner alogkal Systems. 291

iinless that the consistence of these principles be not so
necessarily united as to prevent their separation. For ex-
ample ; if a certain colour was an inevitable consequence of
the presence of a certain constituent part, we might adopt
the colour as a principle of classification, at the same time
with the presence or absence of this constituent part. But,
in doing this, we would admit at bottom but one single
principle as the basis of the system, since the existence of
the one would necessarily imply that of the other. As
M. Werner has admitted external characters to form the
basis of his system, at the same time that he explicitly de-
clares, that " all minerals which have essentially the same
constituent parts both with respect to quality and quantity
form the same species," we must suppose that he has dis-
covered certain connexions which exist between these
characters and the essential chemical composition of the
same mineral. The results of chemical analysis, never-
theless, do not correspond with this supposition; and the
science which unfolds the composition of minerals pro-
nounces it in a manner that does not agree with our re-
ceived ideas of the external characters. At the first glance
over the classification of M. Werner, we may perceive the
difficuliy in which this contradiction involves us; for the
desire of reconciling two things dissimilar in themselves,
has introduced an uncertainty which prevails over all its
parts. If we wish that this celebrated author should re-
main faithful to his principles, I see no other mode than
to suppose that he takes the testimony of external charac-
ters as the index of the chemical composition, rather than
the results of chemistry itself.

Other authors, who have published works according to
the principles of M.Werner, tell us, that although this phi-
losopher considers all minerals which correspond in external
character and chemical composition, as belonging to the
same species, he does not pretend that his arrangement
should agree with the experiments of the chemist. This is
to speak at hazard, and to avow frankly that he regards
theoretical assertions as superior to experience, and the
system which he has adopted as preferable to the principles
of science. It would therefore only be when the chemi-
cal results agree with the external resemblances of minerals,
that they could occupy a place in this system. We see
sensible characters combined with chemical composition to
determine a species ; but if they do not agree with the
results of chemistrv, this science can be of no utility.

T 2 ' Such

292 Reflections on some Miner alogical Systems.

Such ideas will not be very generally received among those
who have studied this science, nor even by those who are
most disposed to discover its imperfections.

INCONSISTENCY- AND UNCERTAINTY OF THE WEKNERIAN
PLAN OF SPECIFICATION.

We now perceive the difficulty of reconciling the im-
mense number of principles which this system has founded,
and the contradictions which the minerals themselves must
render unavoidable in whoever adopts them as a basis. Let
us examine, in a few examples, if their celebrated author
has been able to draw any uniform laws from them. Five
things are to be known, viz.

1st. If all the minerals which have essentially the same
chemical composition are ranged in the same species.

£dly. If all those which have an essential difference in
their chemical composition are placed in different species.

3dly. If all the minerals which differ in more than three
specific characters, whatever may be the number of those
which they have in common, belong to different species.

4thly. If all those which do not differ in more than three
different characters, are ranged in the same species. And,

5thly. If the minerals are always divided into genera, spe-
cies, and varieties, according to their difference ; that is to
say, if those placed in separate genera always differ more
from each other, than those which belong to species, or to
different varieties, &c. ^

The relative condition in the 1st Art. is violated in the
most striking manner by Werner's zirconian genus, which is
divided into three species, and to which chemical analysis
gives the same results. In corundum and adamantine spar
we have two species * with the same chemical composition :
it is the same in appatite, asparagus-stone and phospholite.
Gypsum and fraueneis (selenite) are in a similar state ; and
carbonated lime presents us with no less than the alarm-
ing number of 14 species, which contain eight subspecies
and six varieties.

In the 2d Art. we have beryl which contains glucine
earth, and schorlous beryl which contains none, but which
has instead of it fluoric acid. These minerals, without any

* Here the Wernerians make a distinction without a difference: corun-
dum is used as synonymous with the adamantine spar of Kirwan, and im-
perfect corundum of Orcville and Bournon; while diamond spar is made a
distinct species, although forming only tin.- subspecies corindun harmophane of
Haiiy, or adamantine corundum of Brogniart. — Trans.

affinity

Reflections on some Miner aloglcal Systems, 293

affinity in their chemical compositions, belong to the same
species. (June 1805 *.)

* I shall not stop to give examples proving that the 3d
rule has been abused : it has been violated at almost every
step. In the greater part of the minerals which are but
varieties of the same species, if we examine them closely,
we shall find more than three specific characters which are
dissimilar. The division of characters into generic, specific,
and characters of variety, and the little precision which ex-
ists in all that has been said on the number and importance
of characters, render this examination irksome.

As to the 4th Art. I asked the celebrated author of the sy-
stem of external characters, if there existed a sufficient dis-
parity between the properties of sulphated barytes and sul-
phated strontian to constitute them two species ; and he
answered No. Here chemistry makes two genera where
the external characters would not have two species.

For the 5th Art. there is not less difference between the
garnet and pyrope, quartz and eisenkiesel [iron flint, Jame-
son], beryl and emerald, than between the common or
compact feldspar and hohhpath {made of the French), pot-
ter's clay and sckieferthon [slate clay of Jameson, and argile
feuilletee of Brogniart], mountain cork [asheste tresse of
Haiiy, or A. suberiforme of Brogniart], and amianth, cal-
careous spar, pisolite [peas lone of Jameson, and chaux car'
bonatee concreiionte of Haiiy] and compact, common and
fibrous limestone.

I have chosen only a few examples ; but they are suffi-
cient to prove that there is not one of the rules proposed to
serve as a basis to the system which has not been in-
fringed; sometimes one prevails, sometimes another; and
we can only refer the consequent instability to the insuffi-
ciency of the principles.

PHILOSOPHERS AND PHILOSOPHY OF FREYBKRG.

During a residence of 18 months at Freyberg, where I
had every day occasion to admire the precision and accuracy
with which the learned professor recognized minerals at the
first view, and where I was more than ever convinced by
the example of others of the difference which exists between
the institution of species and the knowledge of individuals,

* Professor Jameson has even gone further, and divided, after Werner,
beryl into two subspecies, calling the one "Jirst subspecies, precious beryl"
(beryl of Kirwan), and the other (isrcoiid subspecies, schorlous beryl," the
pyenite of Haiiy, and shorlite of Kirwan ; thus indicating a relation in nu-
pierical order which has no existence in nature. — Than 3.

T 3 I ncg-

2S4 Reflections on some Miner alogical Systems,

I neglepted no means of forming to myself a distinct idea
of the former. Sometimes they spoke to me of the che^
mical composition ; but when I cited the zircon and hy-
acinth, I was answered, that the external characters made
the difference. If heavy spar and eel es tine were the subject,
they again referred to chemistry. Often they spoke to me
of approximate characters (caractcres des rapprochemens),
or characters of agreement and disagreement, of which no
mention has been made in the enumeration ; and they
quoted to me, as a reason for placing potter's clay (glaise)
and schistose avgil in the same species, that both are disunited
in water. To justify the separation of chalk from mineral
agaric [rock milk, Jameson ; and spongy carbonated lime,
Haiiy], of foaming earth [or schaum earth of Jameson,
silvery chalk of Kirwan, talcous pearly carbonated lime of
Haiiy] from schiejferspatk [slate spar of Jameson, argentine
of Kirwan], they relied on the external characters; and to
prove that bitter spath [muricalcite, Kirwan ; chaux carbo-
natee inagnesifere, Haiiy ; chaux carbonatee lone picrite,
Brogniart] justly makes a species different from calcareous
spar, they turned about to chemistry without daring openly
to claim its support. Sometimes the colours were but
shades or accidents; sometimes they offered characters of
the highest importance. At other moments they confessed
to me that they made species by instinct: and when I com-
plained of not being satisfied with some conclusions indi-
cated by this guide, they answered, " One is not always
in his instinct.^ Finally, after being detected in every
manner, they referred the specification to the tact of the
observer*. But, in this respect, who should venture to
make species if not M. Werner alone?

If I have spoken of these details which I often collected

* True philosophers are deeply indebted to Mr. C. for this clear and
manly exposition of a system not of science but of delusion worthy only of
the lowest religious jugglers and fanatics. The " mineralogical instinct" is
certainly a new faculty discovered in the human mind by, the philosophers
of Freybcrg, whose ardent zeal in propagating their opinions furnishes a
better proof of their passions than of their logic or reasoning powers. It
may, perhaps, be laid down as a general truism, applicable in every branch
of natural philosophy, that all schemes or systems of natural knowledge
may be esteemed scientific or dogmatic just in proportion as their followers
embrace them by reason or by passion. Science is properly a creature of
reason, and modestly retires whenever the passions or affections appear:
opinions, being originally suggested by the feelings, are naturally supported
and propagated bv the passions, while science can only be maintained and
disseminated by close abstract reasoning. Hence it is not difficult to con-
ceive why some of the more imprudent WVrnerians have expressed them-
selves with so much violence against the volume containing the above state-
ment of facts and reflections.— Tran»»

in

Reflections on some Miner alogical Systems. QQ5

in conversation, and if I have quoted the words of other
persons as well as M. Werner, it is to prove that in the
system of external characters there are no principles of spe-
cification which could serve as the basis of any science ; for,
if there had been any, it is more than probable that some
one would have been able to show me them ;and, until that
I receive a clear and distinct answer on this head, I shall
be pardoned for believing and saying that there are none.

BASIS OF A SCIENTIFIC SYSTEM OF MINERALOGICAL
SPECIFICATION.

If in the multitude of properties which distinguish bodies
we are fortunate enough to find those whieh lead to a more
certain and exact determination, let us hope that when pro-
perly unfolded they may be converted into principles, and
that a science shall spring up from the whole. The pre-
cision of the terms which it shall employ will be the mea-
sure of its accuracy, and the definitions become its language.

The knowledge which we have hitherto acquired, fur-
nishes us with two means of appreciating in bodies those
qualities which escape the cognizance of our senses. These
means are physical and chemical ; they unite, to the advan-
tage of being able to appreciate with more precision the
properties which on the first view are but imperfectly dis-
covered, that still greater, of developing the new properties
which are only manifested by indirect means. Having
seen the little success attending the system of immediately
sensible properties, and the little hope which remains of
improving it, since M.Werner has not been able to make
it better, let us have recourse to the succour of these two
sciences to establish minerajogical species.

Physics and chemistry furnish us two modes of attaining
the final results of the division of bodies. Without enter-
ing into useless metaphysical discussions on infinity, we
may suppose any substance whatever reduced to the finest
and most imperceptible particles which the mind can
imagine. This is the last point of physical division, and
one of these grains presents us with the physical element
of a body. Yet this element may be still very compound
in another point of view, and uridergo another species jF
division by means which are properly the province of
chemistry. When the latter is also carried to its ultimate
point, we obtain the chemical element. By physical ele-
ment we understand that which occupies the smallest por-
tion of space which we can conceive; chemical element
supposes the least possible number of component principles.

T4 The

296 Reflections on some Mineralogical Systems.

The forme- eludes our senses by its extreme tenuity long
before it has attained its limit ; the latter would not be less
correctly represented by a mountain of pure silica than by
the smallest atom. The function of the one in nature is to
aggregate itself in quantities more or less considerable to
form masses, from those particles which we can perceive
only by the aid of the mircroscope, to those enormous piles
which we can scarcely embrace in imagination; the office
of the other is to form bodies which we ball compound : thus
the simplicity of one of these elements does not affect the
other. They have nothing in common, but as being the
results to which we are led by the only two means of divi-
sion hitherto known. We may affirm that in every case we
can obtain these results, or that we cannot be obliged to
£ake the limits of our knowledge for those of nature. This
is sufficient; and we are not in opposition to philosophy,
when, in making some efforts to advance towards the end,
we substitute the one for the other; and when we find a
representation, which in every thing essential resembles the
object of research, we may dispense with a rigour which
would in some respects be superfluous.

Hence, from the combination of these elements under
different circumstances, results that infinite variety of
nature which we call fantastical when we do not compre-
hend it ; and it is by depriving the products of nature of
the accidents which alter them, that we bring them back to
that simplicity in which alone they are constant. What,
then, remains for genius to do, but to investigate nature in
a manner in which it cannot escape our researches, and to
obtain unequivocal proofs, or else consider it in a state in
which it ceases to be changeable?,

MECHANICO-CHEMICAL OR CRYSTALLOGRAPHICAL SYSTEM
OF HAUY, AND HIS DEFINITION OF MINERALOGICAL
SPECIES.

Now, what has the author of a mineralogical system
founded on internal properties effected in our times? In-
stead of stopping at the surface, he has penetrated into the
interior of the mineral, and a new world has presented itself
to bis contemplation. He has seen it in its simplicity,
considered the elements which compose it, examined their
habits and mutual relations, discovered the chain which in
an invariable manner unites the final results of the only
two means of division of which we know ^he possibility,
and has defined the species. "The mineralogical species,"
says M. Haiiy, il is a collection of minerals whose integral

molecules

'Reflections on some Miner alogical Systems, 297

molecules are similar, and composed of the same elements
united in the same proportion. " It is the assemblage of
all the minerals which agree, with respect to the final re-
sults of division, in their physical and chemical molecules,
in the true expression of nature reduced to its greatest sim-
plicity*.

This definition of the mineralogical species is rigorous,
and leaves noihing to be desired ; but it requires a know-
ledge of the integral molecules. In the first place, it re-
quires us to ascertain what its form is in all cases similar to
itself: in the second place, we must be able to determine
the nature and relations of its chemical elements. The first
problem consists in finding the planes which terminate the
small solid called the integral molecule, or, what amounts
to the same thing, a solid which may resemble it ; for it is
not the absolute but the relative dimensions of this mole-
cule which are required. But, the planes which terminate
this solid can be but those which are parallel to the different
directions in which a mineral is divisible without break-
insr, or what has been denominated the direction of the
cleavage.

It is otherwise with the problem respecting the chemical
element. We know that there exist vacuums between the
molecules of bodies, and that even these vacuities are very
considerable : hence it is that foreign matters have so often
interposed themselves, and altered the sensible characters
of a group of molecules or of a mass. Suppose that all the
directions of the cleavage parallel to the planes which ter-
minate the physical molecule are ascertained. Whatever
may be the dimensions of the piece in which these direc-
tions are found, we have the representative of the mole-
cule ; but as these dimensions necessarily exceed those of
the molecule itself, it follows that the piece contains more
than one molecule, and hence foreign matters may deposit
themselves in the interstices. Hitherto chemistry possesses
only the means of distinguishing the simple parts which
compose the physical elements from those which are inter-
posed. Hence a source of uncertainty in the results of
chemical analysis j and, in order that it" may enjoy all the

* Most assuredly this conception, even were it devoid of basis, would do
honour to the human intellect. Man is placed in the middle of the universe,
as if to contemplate the infinite space which surrounds him. On whatever
side he looks, — whether he contemplates those worlds whose volumes and
remote distances lire to him without measure, or whether he considers the
atoms which form them and the laws by which these atoms are united, — every-
thing is to him infinite, and begets in his mind that sentiment of sublimity
originating m a grandeur for which we have no expression.

confidence

208 Reflections on some Mineralogical Systems.

confidence which the state of our knowledge should insure
it, we should apply it only to the physical molecules which
have been previously separated one by one to carry off
the foreign matter interposed. But, as the true physical
molecule is situated beyond our means, and the thought
only can reach it, a knowledge of the chemical element
would seem to be too remote for us ever to aspire to it.
Nevertheless nature and labour offer us some means. First,
it does not always happen that the physical molecules are
embarrassed by foreign matter: next, suppose several mi-
nerals whose physical division gives, for instance, an irre-
gular tetrahedron, but in all of uniform dimensions, and
that chemistry finds in one the elements a, b, c,d,e; in an-
other, a, b> c, J; in short, that J, e, and others if we please,
may be variable, but that a, b, c, may be sensibly invariable
in all the different pieces: now the species is unchangeable ;
therefore we have a right to conclude that a, b, c, are the
chemical elements of the species, and that the others are ac-
cidental. Jt is thus that chemistry itself furnishes a method
of correction which has been found sufficiently rigorous,
and the two molecules are still in out power.

Taking the point in its most general sense; every time
that we can discover in any mineral whatever the relative
connexions of the simple component substances which
have been observed to be invariable, as well as the relative
dimensions of the solid which is produced by division in
all the divers directions of the cleavage, we have every thing
necessary to define a species. All minerals, however, do
not present the?e data; and this principle of specification,
however precise it may be, does not embrace the whole of
the mineral kingdom.

Let us suppose a thousand individuals or mineral .mole-
cules of a single species suspended in the same solvent.
By a diminution of the dissolving power, these individuals
would tend to unite themselves in groups; it might then
happen either that the molecules should assume such an
arrangement as the aggregate would easily yield to me-
chanical division, whence we might extract the integral
molecule of the species or its representative J or that the
molecules might unite confusedly in an irregular mass, so
that the t vpe of the species could not be. recognized. Again ;
if wc suppose the molecules of several species in the same
solvent, we shall have two analogous cases ; the molecules
of each species might unite to form aggregates of sensible
dimensions, and aherwards concur in the formation of the
mass, in which each species would be perfectly discerni-
ble;

Reflections on some Mineraloglcal Systems. 299

ble 5 or, tljey might be so blended together in iheir origin,
that in the mass which would be produced, it would be im-
possible to discover one simple species whose molecules
had contributed to form it.

TRUE PRINCIPLES OP FORMING MINERALOGICAL SPECIES.

In the mineral kingdom, therefore, we must admit the
following four conditions, arising from circumstances which
have presided at the formation of minerals :

] st. Simple minerals whose molecule we are able to dis-
cover :

2d. Simple minerals whose molecule -eludes our re-
searches :

3d. Compound minerals in which the simple component
minerals are discernible:

4th. Compound minerals in which we cannot distinguish
the simple components.

Of these four conditions there is but the first which gives
the species with strictness, and which truly appertains to
science; but the others belong to nature, and must not be
excluded from the method of classification. If, then, we
find in any mineral, characters sufficiently marked to esta-
blish a well-founded opinion that it is of the same species
with some one of the first section, we refer it by analogy to
this, and consider it as belonging to the same species.

What is carbonated lime? — It is a mineral composed of
0*55 lime, and 0*45 carbonic acid, and which has for its
molecule an obtuse rhomboid, whose great angle is 101*
32' 13". Here is carbonated lime defined ; and it is evi-
dent that in our principles a mineral which has these pro-
pertiesnecessarily belongs to this species. What is com-
pact carbonated lime ? — It is a mineral whose chemical com-
position makes us presume with the utmost likelihood that
it is of the same species as crystallized carbonated lime,
and that it differs only in the circumstances under which it
has been formed, not having permitted the symmetrical ar-
rangement of its molecules, so that one might extract from
the mass the solid, which it represent*;. Here the type is
but presumed ; and it is only after strong proof from ana-
logy that we resolve to class in the species of carbonated
lime, a substance which cannot be proved strictly to belong
to it.

In granite, gneiss, and porphyry wc distinguish the pieces
of simple minerals or which they are composed. They appear
to have enjoyed in their formation fill the circumstauces
which could favour the union of the molecules of the same

species

300 Reflections on 'some Mlneralogical Systems.

specie^ together, to form masses of a perceptible magni-
tude. If the result appears to be invariable, at least in
what relates to the general mode of aggregation, should it
be every where the same, we shall be obliged to admit that
nature here also works by immutable laws, and that we
must find means to comprehend them in the system of
science. These masses will therefore be mixed species,
and appertain to geognosis; they will be strictly gcognostic
species, seeing that the simple minerals of which they are
composed are so, that in their union they have observed
invariable laws, and that it is no more difficult to pro-
nounce on three species united, provided that the specific
character be there distinctly visible, than on three species
when thev are separated.

The minerals in the fourth condition constitute the
greatest difficulty in mineralogy. This science here finds its
cryptogamia.

The analogy which led us to assign a place to the con-
fused mixtures of molecules of one species, abandons us as
soon as we wish to apply it to pieces which are composed
of imperceptible molecules of divers species. In the sup-
position that we cannot discern those molecules of each
species, it is impossible to refer the piece with propriety to
any one. ,But if we observe in these masses the same con-
stancy of character as in the mixtures of perceptible species,
although we can demonstrate nothing in their constitution,
we must assign them a place, and the appreciation of na-
ture here be abandoned in some measure to the conscience
of the observer. The tirst difficulty is to know what is the
number of different species, the molecules of which have
contributed to the formation of the mass. Suppose an ag-
gregate in v\ hi eh we cannot discover any form of mole-
cule, which at the same time effervesces with acids, and
emits fire with steel, of which one part dissolves in muriatic
acid, leaving carbonic acid gas to escape, while the other is
entirely insoluble ; that the dissolved part be lime, the
other silica *, To what species shall it be referred ? Is it
even possible to refer it to any ? There is carbonated lime
and silica, and our operations inform us that there has been
a mixture of the two species. But this advantage, how-
ever weak it may be, no longer exists, if all the molecules
which are found in the same mass act in the same manner
with the same chemical and physical instruments; and wc
have no more resources to learn if it is composed of mole-
cules of one species, of two, or of several. I shall cite the
agate, jaspjr, hornstUnc, and the long list of species which

are.

Reflections on some Miner ah glcal Systems, 301

are found in the argillaceous or clay genus of Werner, of
which we are ignorant, and perhaps for ever shall be ig-
norant, to hovv"niany simple species they owe their origin.
What do we know of the family of argillaceous schist, of
serpentine, of pierre ollaire [potstone, Jameson ; talc o/-
laire, Haiiy, and serpentine ollaire, Brogniart], of pipe-clay,
and of fuller's earth ; except that we do not conceive why
they have been made strictly species? Whenever a mineral
gives no true representative of the species, and that we do
not there find other physical or chemical properties to re-
fer it with sufficient certainty to any whatever, in which it
may be strictly admissible, it is better to make it a species
of convention, in order to complete the outline which na-
ture has traced.

DISTINCTION BETWEEN MINERALOGICAL SPECIES.

In this point of view, the species of the mineral kingdom
should be divided into four sections, corresponding with
the four conditions of which I have already spoken. The
first should contain the species strictly so called (especes de
rigu'eur); the second, those by analogy; the third, those
which I call geognostic ; and the fourth, those of conven-
tion. All belong to nature ; the first only appertains to
science, if we wish to preserve to this word that idea of
rigour which it necessarily carries with it.

The principle of M. Haiiy embraces all those which are
known in the first section, therefore this system embraces
all the mineralogy which is capable of beeoming a science.

The method of M. Werner extends to all the mineral
kingdom. il Who embraces too much, badly binds," it is
said: thus we know not what is a species, because all are
species. We have a measure without unity.

I pretend not that the system of mineralogy should
be subjected to the division indicated by these four sec-
tions; but if we wish to consider the bodies which com-
pose this kingdom with respect to the rank which they
ought strictly to occupy, we can no longer divide them
otherwise ; and even in classing them according to more
essential principles, it would not be useless to mention this,
in order that each individual may be estimated at its just
value.

The advantages that mineralogy has derived from the
philosophic spirit which directed the researches into the
true type of the species, and the happy application of an
exact method of determinating it, have been immense. All
at once it is become a science ; it is supported by fixed

principles

302 Reflections on some Miner alogicat Sy sterns*

principles susceptible of demonstration, and has resolvecf
problems, enlightened futurity, and anticipated the results
of analysis.

SYSTEM OF HAUY AND WERNER CONTRASTED.

By a happv anticipation of chemistry, which has been
confirmed by experiment, we owe to the system of latent
properties the union of beryl with emerald, granatite with
staurolite, as well as the separation of chabasie from anal-
cime [both are denominated cubic zeolite by Werner and
his disciple Jameson], stylbite [foliated zeolite, Jameson]
from mesotype [radiated zeolite, Jameson], and the acan-
ticone from thallite. It has left existing the harmony by
which nature has united zircon, hyacinth, and zirconite ;
garnet and pyrope, quartz and eisenkiesel (iron flint). It
has not made a mineralogical species of heliotrope, com-
posed, according to Werner, who admits it as a species, of
chalcedony and green earth, of prase, which consists ofquartz
and straldstein [actinolite, Jameson ; actinote, Haiiv j am-
phibole actinote, Brogniart]. It has not placed sapphire
and corundum in two different genera; but agreeing with
chemistry, and renouncing prejudices, it has not classed a
fossil entirely composed of alumine in the siliceous genus
merely because it is hard. It lias no repugnance to the
admission of the diamond among combustibles. In the
argillaceous genus, where the subdivisions are so little cha-
racterized, it has not made 3-2 species no more than 14 in
carbonated iime, nor two in sulphated lime, or four in sul-
phated barytes ; and above all, we have not 103 species m
the earthy fossils. It has not transposed a mineral this
year to the side of a species from which it was separated in
the preceding, and which some mouths after will be chased
from the side of its new neighbour to pursue its fortune
elsewhere. It has not made different species, the one after
the other, traverse the whole fist of minerals, without being
able to find where to fix themselves, like those importunate
guests, who go every where and whom all persons evade.
lis principles are fixed ; and although it occupies more
time to pronounce, it virtually decides sooner, as it dis-
poses more surely and leaves nothing arbitrary. It neither
makes distinctions without differences, approximations [r#p-
proc/iemens] without analogies, nor species without cha-
racters.

Notwithstanding, it will not pretend that minerals should

persevere in retaining a rank which principles refuse them ;

nor will it deem the circumstance a misfortune, that the

* * science

On the Decomposition of Water ly Charcoal. 303

science varies in gaining new means of improving itself.
Since the publication of his work, M. Haiiy has already
made considerable changes in his system, but all of them
were foreseen and previously indicated, with the single ex-
ception of sphene, which he then knew only by some in-
distinct crystals. When one has laid down certain princi-
ples, the path of science is then found circumscribed, but
its march is direct : it it change, it is only for a rational
melioration, and it proceeds in advancing. If delivered to
the current of opinions, or of hypotheses, it is discussed in
every sense, and fortunate if it does not retrograde. For it
there is no more surety, each one buffeting it at his pleasure.
To reform is a great art, and to retouch without defacing
requires great ability. Principles produce improvements,
arbitrariness induces revolutions.

M. Haiiy had formerly determined the molecule of spar-
gelstein [asparagus -stone, the chaux phosphatce chrysolithe
of Haiiy and Brogniart] as well as that of appatite; but at
an interval of several years, as the idea of comparing his
results did not occur till M. Vauquelin had discovered that
spargelsiein is a phosphate of lime. Here chemistry was
found to agree with crystallography.

A mineral was discovered, which some thought to be of
the calcareous genus, which dissolved in acids without
either effervescing or emitting fluoric acid., but which never-
theless gave traces of a combination with an acid ; and M.
Werner pronounced it a phosphate of lime. He was not
deceived ; but the difference which there is between reason-
ing and divining, is, to set out on a principle, or to start at
hazard. Yet, even in setting out on a principle, we are
not always sure of reasoning. Phosphorus in burning is
phosphorescent and odorous ; quartz when rubbed has the
same properties; therefore silica is composed of phosphoric
acid and lime. It is thus that a very celebrated German
professor spoke, and he pretended to reason : his preten-
sions were so much the greater, that the combination of
phoshoric acid and lime is neither phosphorescent nor
odorous.

[To be continued.]

LVIT. On the Decomposition of Water hy Charcoal. By
M. Tordeux, Student of Chemistry in the Polytechnic
School*.

Xn the note at the end of the observations of M. Flguier,
«n the sulphurets contained in the soda of commerce, in a

• Annaits dc Chimiot tome lxvi. p. 318. preceding

304 On the Decomposition of Water by Charcoal.

preceding Number of the Annales, M. Figuier adduces an
example of the explosions which sometimes take place in
soap-works, which he ascribes to the hydrogen cas mixed
with atmospheric air, existing in the interior of the
vat, above the caustic lixivium ; and he explains the for-
mation of this gas, by supposing that the sulphurets which
crude soda contains, set free a quantity of hydrogen ex-
ceeding that which is necessary for the formation of the
hvdrogenated sulphured when we treat this kind of soda
with water.

We know that when an alkaline sulphuret is put into
water, the latter is partly decomposed. A sulphate is
formed, and the hydrogen set at liberty is combined with
the remains of the sulphur and the base, in order to form a
hydrogenated sulphuiet. We know also that in this ex-
periment there is no extrication of gas if we operate at a
low temperature.

Hence it is evident that the hydrogen gas which swims
over the soap-maker's ley, does not proceed from the de-
composition of the water by the alkaline sulphuret.

I have been led to ascribe the production of this gas to
the charcoal always met with in the soda of commerce, by
a remark which I made several months ago. I had ob-
served that potash purified by lime, which had been long in
contact with vegetable substances, and which was strongly-
coloured by the charred substances which it had taken up
from them4, when fused in a crucible, gave out a great deal
of gas which took fire spontaneously ; and when the alkali
was red hot, its combustion resembled that of hydrogen
gas.

It appeared to me on reading the memoir of M. Figuier, that
the hydrogen of which he speaks might have been pro-
duced by a nearly similar cause. I made some experiments
on this subject, and the object of this note is to detail the
results.

The potash, on which I made the first observation, be-
sides charred substances, also contained a quantity of water,
the more considerable, as it had not been reddened in the
desiccation 5 and all circumstances being favourable, it ap-
peared tome that the carbonic acid might have been formed
in this case by the resulting attraction of charcoal for oxy-
gen, and of potash for this acid ; and that the hydrogen gas
must have been extricated pure or carburelted.

In order to ascertain if this was really the case, 1 distilled
in a stone retort, potash similar to that which I had used in
the crucible : in an instant the heat was sufficient to drive

off

On the Decomposition of Water ly Charcoal. 305

oflf water from the potash, and a gas began to be set free,
which issued incessantly during parts of the operation. This
gas was insoluble in water; it had a feeble empyreumatic
smell ; it did not disturb lime water, and it was inflam-
mable, burning like a mixture of hydrogen gas and carbu-
retted hydrogen gas : it made lime water turbid after its
combustion; when mixed with oxygen in Volta's eudio-
meter, it detonated by the electric spark.

The disengagement was kept up a long time at a weak
heat ; nevertheless I increased the fire until the bottom of
the retort was red hot : I always obtained the same product,
only the hydrogen became purer.

After some lime the disengagement of gas slackened. I
increased the fire : and when the retort was very red it be-
gan again; but the gas which I obtained this time was en-
tirely absorbed by the water, and by the lime water which it
rendered turbid. It was no longer inflammable, and proved
to be pure carbonic acid. At the end of the operation, how-
ever, it left a combustible residue, when it was shaken with
lime water: this residue was probably gazeous oxide of car-
bon. The potash had become almost white, and the re-
tort was attacked.

It appears to me that we may explain this operation in,
the following manner : The water in presence of the char-
coal and of the potash, acts in the same way as when it is
in contact with an alkaline sulphuret or phosphuret. Car-
bonic acid and a carbonate are formed; since the potash
purified by lime may contain at this temperature a greater
quantity of carbonic acid than that which it contains al-
ready ; and if when the retort is red hot it is extricated from
this acid, this perhaps is merely owing to the combination
of the potash with the earths of the retort, a combination
which does not admit of the presence of carbonic acid.
Lastly, the gaseous oxide of carbon certainly proceeds from
the decomposition of a little acid by a residuum of charcoal.

I confirmed this experiment on potash very much charred
and carbonated, obtained in the following manner : — I eva-
porated to dryness alcohol containing a great quantity of
potash in solution; not effervescing with the acids, but
very high coloured, although transparent. The evapora-
tion was effected in a silver vessel in order to obtain pure
potash : in proportion as the operation advanced, the potash
became very black ; and towards the end it swelled up, giv-
ing out an inflammable gas: filially, it became dry and
spongy. It was treated with water, and evaporated to dry-
ness without filtering ; it was black like charcoal, and ef-

Vol. 36. No. 150. Oct. 1810. U 'fervesced

306 Expulsion of Tcenia hj Oleum Tcrelinlhince.

fervesced a little. It was in this state that I submitted it
to distillation in a stone retort, as 1 had done with respect
to the lime potash. The results of the operation were ab-
solutely similar ; and when I removed the potash from the
retort, it was white, and exhibited some effervescence.

I should in all probability have obtained the same results
with soda purified by lime, if I had subjected it to the same
experiments, considering the great resemblance which exists
between these two alkalis.

In order to assimilate my experiments a little- with those
which are performed on a great scale in the soap-works,
it remained to form the caustic lixivium of the soap-makers,
and to observe what took place in this operation. With
this view I made a paste with 500 grammes of pulverized
alicant soda, and 250 grammes of lime newly slacked. I
diluted it in water, and left it ten or twelve days at a tem-
perature from 10° to 15° of Reaumur in a proper apparatus.
Some bubbles of azotic gas only were set free. Although
the result of this last experiment teaches us nothing satis-
factory, I am not less inclined to think that the hydrogen
gas, whether pure or carburetted, which is produced in soap-
works, is owing, as 1 have observed above, to the decom-
position of water by charcoal. In fact, it is not to be
doubted that the circumstances of this experiment are ex-
tremely different from those which we meet with in the
manufactories where large masses are operated upon, or
where '.he soda employed is better adapted for the opera-
tion, either from containing more charcoal, or from being
in more minute division. In short, there is a variety of cir-
cumstances which must' necessarily modify the results.

LVIII. Cases illustrating the. Effects of Oil of Turpentine
in expelling the Tape- worm.

Case I.'
By John Coakley Lettsom, M. D. and President of the
Medical Society.

JCiARLY in September 1809, I was consulted by J. 1\ esq.,
about thirty-five years of age, on account of an uneasiness
in the abdomen, with dyspepsia, which were supposed to
originate fitofri Uenia, or tape-worm, as small portions of it
had occasionally been evacuated bv the rectum.

I prescribed a course of the male fern, with occasional

* From Transactions of the Medical Sscietij of London, vol. i- part I.

caihartics,

Expulsion ofTcenia by Oleum Terebhithince . 307

cathartics, as recommended by Madame Nouflet. In this
plan he persevered for the space of three months, in which
period he discharged, at two different times, about eight
yards of the taenia. In April 1810, he again applied to
me, in consequence of labouring under his former com-
plaints ; adding, that he imagined, from the long use of the
plant I had recommended, his pains, and particularly the
dyspepsia and general debility, had increased.

At this time I ordered the oleum terebinthinae rectifica-
tum, in a dose of nine drachms by weight,-and after it a
little honey to remove the heat and unpleasant taste it might
occasion. In a week after taking the oil, he called upon
me agreeably to my request, and gave me the following in-
formation : That, as far as he could judge, in swallowing
this medicine, it occasioned less heat than would have re-
sulted from taking the same quantity of brandy, or other
spirit ; and that the taste and heat it produced were soon
removed by the honey.

In about three hours after taking this dose, a laxative
motion was produced, without any discharge of taenia : but
soon afterwards, with the second stool, more than four
yards of the worm were discharged, and also a quantity of
matter, resembling, as the patient expressed it, the substance
and skins of the taenia. On the surface of this evacuation
he noticed the oil floating, together with the taenia and the
substance mentioned. It produced little or no pain, and
certainly much less than the purgative he had taken after
the use of the male fern. The subsequent motions con-
tained no taenia, nor any of the substance before noticed.
He experienced no pain or heat in the urinary passages,
though the urine continued to impart a terebinthinate smell
for three or four successive days.

My patient has since remained in perfect health, enjoy-
ing a degree of comfort to which he had been a stranger
for the preceding half year.

From this andother instances, I am induced to conclude,
that the best method of taking the oil is without any ad-
mixture; and that the dose of nine drachms occasions very
little inconvenience : and further, that this quantity, per-
haps owing to its quick purgative effect, excites no irritation
in the urinary passages, although it imparts its peculiar
smell to the urine.

I do not recollect that it has been heretofore observed,

that the oil has been evacuated in its original state. It

might hence be inferred, that it is most efficacious when

v U2 exhibited

308 National Vaccine EstalUsh?kenl.

exhibited uncombined, in which state it is not attended
with any particular inconvenience.

It is well known that taenia may exist in a healthy state
of the system; and that hence its presence cannot be ac-
curately ascertained by any other circumstance than the
actual discharge of portions of the worm itself. Some-
times, indeed, there is felt a heavy pain in the epigastrium,
attended with dyspepsia and emaciation; but these are not
pathognomonic symptoms, as they may arise from other
causes.

fTo be continued.]

LIX. Intelligence and Miscellaneous Articles .

NATIONAL VACCINE ESTABLISHMENT.

JL he Board appointed by His Majesty's Government to
regulate the affairs of this establishment has ordered that
the following description of the vaccine vesicle, and in-
structions relative to vaccination, which have been pre-
sented by the director, be strictly observed by the vacci-
nating surgeons.

Description of the regular Vaccine Vesicle.

When vaccination succeeds, a small red spot is observa-
ble on the third day, the day the operation is performed
being reckoned the first. If the spot is touched, an eleva-
tion is felt ; and if examined with a magnifying glass, the
little tumour appears surrounded l>y a very slight efflores-
cence.

The spot gradually enlarges ; and between the third and
sixth day a circular vesicle appears. The edge of the vac-
cine vesicle is elevated, the centre depressed. The colour
is at first of a light pink, sometimes of a blueish tint ; and
changes by degrees to a pearl colour. The centre is some-
what darker than the other parts.

The vesicle is hard to the touch.

In its internal structure it is cellular; the cells being filled
with transparent lymph.

The vesicle commonly augments till the tenth or eleventh
day.

In the early stages, there is usually round the base an
inflamed rirg; or this takes place on the seventh or eighth
day; towards the ninth it spreads rapidly, and near the
tenth forms an areola of about an inch and a half in diameter.

This areola is of the usual colour of inflamed skin; it is
bard, and accompanied with some degree of tumefaction.

H

National Vaccine Establishment. 309

It continues out for a day or two, and then begins to
fade ; sometimes forming two or three concentric circles.

After the areola is formed, the vesicle begins to decline ;
the centre first turns brown, and the whole gradually changes
into a hard smooth scab, of a very dark' mahogany colour.
This dry crust usually drops off about the end of the third
week, leaving a permanent cicatrix.

Varieties in the Progress and Appearance of the Vaccine Ve-
sicle, not preventing the Success of Vaccination.

The first appearance is seldom earlier, but often later
than has been described. In some rare instances the vesicle
commences even a fortnight or three weeks after vaccina-
tion ; but if the process is then regular, it is equally effica-
cious.

When the vesicle is slightly ruptured before the sixth
day, if it resume its proper form, and the process continue
quite regular, success is not prevented : nor is it, when the
crust of a regular vesicle is rubbed off in the decline of the
disease.

The irregular and imperfect Vesicle and Pustule, which are
not to he depended upon.

In these deviations there is usually a premature itching,
irritation, inflammation, vesication, or suppuration. Or
the' progress of the vesicle is too rapid, its texture soft, its
edge not well defined, its centre elevated, and the contents
discoloured or purulent. Or instead of a proper areola, a
premature efflorescence of a dusky purple hue takes place,
and the scab is of a light brown or amber colour.

The irregular vesicle or pustule is more liable to be broken
than the other, both from its more pointed form and softer
texture, and also from its being usually so irritable as to
provoke scratching. When broken, or even without this
happening, ulceration often ensues.

A vesicle, apparently regular at first, sometimes does not
augment to the proper size, but dies away without com-
pleting the regular process. This usually leaves no cicatrix,
or one which is almost imperceptible.

When those, or any other considerable deviation from
the regular course of the disease take place, no dependence
can be placed upon the operation. In such cases vaccina-
tion should be repeated.

Probable Onuses of irregular Vesicles and Pustules.
These accidents may be occasioned by matter or Ivinph
being taken from an irregular vesicle or pustule at any pe-
riod, or from a regular vesicle at too late a period ; or by

U 3 lymph

310 National Vaccine Establishment.

lymph, though originally pure, which has been injured by
long keeping, by heat, or otherwise. Or they maybe caused
by performing the operation with rusty or unclean lancets,
or in a rude manner, or by injuring the vesicle at an early
stage, and thereby exciting too much inflammation, or in-
terrupting the regular progress of the disease. Herpetic
eruptions, and other cutaneous affections have also been
supposed the cause of these irregularities, and occasionally
to prevent the vaccine lymph having any effect.

The Methods of taking Vaccine Lymph for Vaccination.

The lymph of a regular vesicle is efficacious from the
time it is secreted, till the areola begins to spread. It
may therefore commonly be taken till the ninth day j but
not after the areola is. formed.

The lymph is to be taken by small superficial punctures
made in the vesicle with the point of a lancet. Time should
be allowed for the liquid to exude, which will form small
pellucid drops. When requisite, a very slight pressure may
be cautiously applied with the flat surface of the lancet.
Great delicacy is requisite in this operation ; for if the ve-
sicle is rudely treated, or too much opened, inflammation
and ulceration may ensue.

Lymph intended to be used immediately, or in a few
days, may be received on a lancet ; but this is an improper
instrument for preserving it longer ; for the lymph soon
rusts the lancet, and it is then liable to be inefficacious or
injurious. (Quills and toothpicks succeed; but small bits
i of ivory shaped like the tooth of a eomb, and properly
pointed, are the most convenient instruments; and to ren-
der them more certain, they should be charged repeatedly.

In order to preserve lymph for a long period, the best
method is by two bits of square glass. The lymph is to
be received on the centre of one of them, by applying it to
a punctured vesicle. When fully charged and dry, it is to
be covered with another bit of glass of the same size, and
wrapped up in paper or in gold-beater's skin.

In whichever way the lymph is taken, it should be al-
lowed to dry without heat in the shade, and be kept in a
dry and cool place. When inclosed in a letter, if great care
is not taken, it may be injured by the heat of the melted
wax in sealing the packet.

The Mode of Vaccinating. - k

Liquid lymph is better than dry, because it seldomer fails,
and the operation is more lightly and quickly performed.
Therefore, in every instance where it is practicable, the pa-
tient

National Vaccine Establishment < 311

tient from whom the lymph is to be taken should be present,
and the lymph should be transferred from the one to the other.

Vaccination is generally performed in the arm near the
insertion of the deltoid muscle ; but in order to hide the
scar, and in adults who are likely to use the arm much, it
may be adviseable to vaccinate the outside of the leg, a little
above or below the knee.

The skin being stretched, a lancet charged with vaccine
lymph should be held with its flat surface to the skin; and
the point insinuated slantingly through the cuticle till it
touches the cutis. It should be retained there for a few
seconds.

The lancet should be dipped in water and wiped after each
operation, even when several successive inoculations are to
be performed.

Dry lymph on glass may be moistened with a very little
cold or tep>id water on the point of a lancet, allowing it
some time to dissolve, and blending it by a little friction
with the lancet. It must not be much diluted, but of a
thick consistence : it is to be inserted in the same manner
as the recent fluid.

When quills, ivory lancets, or toothpicks charged with
dry lymph are used, the lymph should not be diluted ; but
a puncture having been first made with a common lancet,
the point of the instrument is to be inserted, and held in
the puncture half a minute or more, that the lymph may
gradually dissolve and remain in the wound. If the part of
the instrument which is charged be afterwards wiped re-
peatedly upon the edges of the puncture, it will tend still
further to ensure success.

Vaccinated patients must 'be cautious not to wear tight
sleeves, nor to injure the vesicle by pressure, friction, or
any other violence; lest considerable inflammation or ul-
ceration should ensue.

One perfect vaccine vesicle is sufficient ; but. for various
reasons it is always prudent to make two or three punc-
tures, especially when the danger or receiving the small-pox
is imminent, the lymph dry, or the patient's residence di-
stant. Besides, greater securitv is obtained against a chance
of failure from the derangement or destruction of one ve-
sicle by accidental injury, or by the taking of lymph for
vaccination. When two punctures are to be made m oue
limb, they should be at least two inches asunder, on ac-
count of the irritation they may occasion.

One vesicle should be always permitted to go through its
course without being punctured.

Lancets for vaccination should be kept clean and bright.
U 4 Constitutional

312 National Vaccine EsiaU'ishment .

Constitutional Symptoms,

Constitutional symptoms sometimes occur at a very early
period, but more commonly from the seventh to the ele-
venth day. These are drowsiness, restlessness, a chilliness
succeeded by heat, thirst, head-ach, and other marks of
febrile affection. Now and then sickness or vomiting takes
place, especially in infants.

The constitutional symptoms are in general slight and
transient.

in a great proportion of cases there is no perceptible in-
disposition ; nevertheless, the person vaccinated is not the
less secure from the future infection of the small-pox, pro-
vided the progress of the vesicle has been regular and com-
plete.

Care should be taken not to confound the symptoms of
other diseases with those produced by vaccine inoculation.

Medical Treatment,
In general no medicine is required in this mild affection ;
but if the symptoms happen to run a little higher than
nsual, the same remedies are to be applied as if they pro-
ceeded from any other cause.

No preparatory medicines are necessary before vaccinating,
and commonlv no cathartics need be given afterwards.

Should the local inflammation exceed the usual bounds,
which rarely happens, unless from tight sleeves, pressure,
or friction, it may soon be checked by the frequent appli-
cation of compresses of linen dipped in water, in liquor
Plumbi Acetatis dilutus, or in a solution of one drachm of
Plumbi Superacetas in a pint of water. These are to be
applied cold.

If the scab be rubbed off prematurely, and ulceration take
place, cooling and astringent applications may be used ; such
as a drop of liquor Plumbi Acetatis, which should be allowed
to dry on the part, and then be covered with compresses
dipped in water, or in either of the preparations of lead
above-mentioned, and frequently renewed.

When ulceration is deep or extensive, a poultice either of
bread and milk, or of bread with any of the preparations of
lead may be applied, as the case seems to require. They
must never be applied till they are nearly or quite cold.

In Such foul and obstinate sores as resist the foregoing
applications, the Unguentum Hydrargyri Nitratis, mixed
with an equal quantity o\^ Unguentum Cetacei or other si-
milar applicat: * - nipy sometimes be resorted to with advan-
tage. And at other times these sores may be healed by the
Ceratum Plumbi Superacetatis, or the mildest applications.

The

Mount Vesuvius. 313

The irregular vesicles and pustules are frequently fol-
lowed by ulceration at an early period, which is to be treated
in the same manner as if it proceeded from the regular ve-
sicle.

"When the patient has been previously exposed to the in-
fection of small-pox, this disease will be either superseded
or not, according to the time which has elapsed before vac-
cination.

Medical gentlemen in all parts of the empire may be
supplied with vacciue lymph, without any expense, from
the National Vaccine Establishment.

Applications for lymph, letters, and communications re-
specting vaccination, will meet with proper attention: they
should be addressed to Dr. Hervey, register, Leicester-
square ; and when from a distance, put under a cover, di-
rected to The Right Hon. the Secretary of State for the
Home Department.

Board Room, 21, Leicester Square, Feb. 22, 1810.

MOUNT VESUVIUS.

Naples, Sept. 24.

The recent eruption will make the year 1810 an epoch in
- the annals of Vesuvius, on account of the manner in which
it began, and the. disasters it has produced. It is considered
as a very extraordinary circumstance that this eruption was
not preceded by the usual indications ; every convulsion of
Vesuvius being previously announced by the drying up of
the wells of Naples. This phenomenon did not take place
on this occasion, and, to the great surprise of the inhabi-
tants, Vesuvius began to emit flames on the night of the
10th of September.

On the morning of the 1 1th the flames became more in-
tense, and the lava began to flow from the east and south-
east sides of the mountain. Towards evening the confla-
gration increased, and about twilight two grand streams of
tire were seen to flow down the ridge of the volcano; night
produce4 no change in this stale of things.

On the morning of the 12th a hollow sound was heard,
which continued increasing; the fire and smoke ;also aug-
mented in intensity, and towards evening the horizon was
obscured. The breeze, usual in these parts, having blown
from the south-east, dissipated the accumulated clouds.
The mountain continued to vomit lava and a dense smoke,
which even at a distance was strongly sulphureous; the
hollow noise in the sides of the mountain continued to
increase.

Curious

314 Mount Vesuvius,

Curious to witness as near as possible one of the most
astonishing phcenomena of nature, and forgetting the mis-
fortune of Pliny, I set out from Naples, ana at eight in the
evening I reached Portici. From thence to the summit of
the mountain the road is long and difficult. About half
way there is a hermitage, which has long served for
refuge and shelter to the traveller: — a good hermit has
there fix. d his residence, and takes care to furnish for
a moderate sum, refreshments, which to the fatigued tra-
veller are worth their weight in gold. The environs of
this hermitage produce the famous wine called Lachryma
Christi. — From the hermitage to the foot of the cave there
is a long quarter of a league of road, tolerably good; but
in order to reach from thence the crater, it is necessary to
climb a mountain of cinders, where at every step you sink
up to the mid- leg. It took my companions, myself, and
our guides, two hours to make this ascent ; and it was al-
ready midnight when we reached the crater.

The fire of the volcano served us for a torch ; the noise
had totally ceased for two hours ; the flame had also consi-
derably decreased : — these circumstances augmented our se-
curity, and supplied us with the necessary confidence in
traversing such dangerous ground. We approached as
near as the heat would permit, and we set fire to the sticks
of our guides in the lava, which slowly ran through the
hollows from the crater. The surface of this inflamed matter
nearly resembles metal in a state of fusion ) but as it flows
it carries a kind of scum, which hardens as it cools, and
then forms masses of scoria, which dash against each other,
and roll all on fire, with noise, to the foot of the mountain.
Strong fumes of sulphuric acid gas arise in abundance from
these scoria, and by their caustic and penetrating qualities
render respiration difficult.

Wc seemed to be pretty secure in this situation, and were
far from thinking of retiring, when a frightful explosion,
which launched into the air fragments of burning rocks to
the distance of more than 100 toises, reminded us of the
danger to which we were exposed. None of us hesitated
a moment in embracing a retreat ; and in five minutes we
cleared in our descent a space of ground which we had
taken two hours to climb.

We had not reached the hermitage before a noise more
frightful than ever was heard, and the volcano, in all its
fury, began to launch a mass equal to some thousand cart-
loads of stones and fragments of burning rocks, with a
projectile force which it would be difficult to calculate. As
the projection was vertical, almost the whole of this burn-
ing

Serpents in America. 3 1 5

ing mass fell back again into the mouth of the volcano,
which vomited it forth anew to receive it again, with the
exception of some fragments which flew off, to fall at a
distance, and alarm the inquisitive spectator.

The 13th commenced with nearly the same appearances
as those of the preceding day. The volcano was tranquil,
and the lava ran slowly in the channels which it had formed
during the night ; but at four in the afternoon a frightful
and continued noise, accompanied with frequent explosions,
announced a new eruption : the shocks of the volcano were
so violent, that at Fort de L'CEuf, built upon a rock, where
I then was, at the distance of near four leagues, I felt oscil-
lations similar to those produced by an earthquake.

About five o'clock the eruption commenced, and con-
tinued during the greater part of the night. This time the
burning matter flowed down all the sides of the mountain,
with a force hitherto unprecedented; all Vesuvius seemed
on fire. The lava has caused the greatest losses : houses
and whole estates have been overwhelmed ; and at this day
families in tears and reduced to despair, search in vain for
the inheritance of their ancestors, buried under the destroy-
ing lava.

At ten at night the hermitage was no longer accessible;
a river of fire had obstructed the road. The districts situ-
ated on the south-east quarter of the mountain had still
more to suffer. Mount Vesuvius presented the appearance
of one vast flame, and the seaman at a great distance might
contemplate at his leisure this terrific illumination of nature.

SERPENTS IN AMERICA.

The following is translated from the Reading (Pennsyl-
vania) Eagle. — A daughter of Mr. Daniel Strohecker, near
Orwigsburg, Berks county, Pennsylvania, about three years
of age, had been observed for a number of days to go to a
considerable distance from the house with a piece of bread
which she obtained from her mother. The circumstance at-
tracted the attention of the mother, who desired Mr. S. to
follow the child and observe what she did with it. On
coming to the child he found her engaged in feeding several
snakes, called yellow heads or bastard rattle snakes. He
immediately took it away, and proceeded to the house for
his gun, and killed two of them at one shot, and another a
few days after. — The child called these reptiles in the manner
of calling chickens ; and when its father observed, if it con-
tinued the practice they would bite her — the child replied —

" No,

3 1 6 Native Magnesia. — Meteoric Sio?ics. — Coffee,

" No, father, they won't bite; they only eat the bread I
give them."

NATIVE MAGNESIA.

Although magnesia enters into the composition of many
mineral substances, yet its existence in the mineral king-
dom, in an uucombined state, has, till within these lew
years, been unknown.

At Hoboken, in New Jersey, on the estate of Mr. John
Stevens, is found a mineral which, agreeably to the experi-
ments of Professor Bruce, of New Jersey, contains in the
hundred parts,

Magnesia 70

Water of crystallization 30

100,

SHOWER OF METEORIC STONES IN NORTH AMERICA.

Raleigh, New Connecticut, March 1, 1810.

On Tuesday, the 30th of January last, at two o'clock
P.M. there was a fall of meteoric stones in Caswell county.
Their descent was seen for a considerable distance round,
and two reports distinctly heard at Hillsborough, a distance
of 50 miles. — A fragment weighing a pound and three
quarters struck a tree in the new ground of a Mr. Taylor,
r.ear where some woodcutters were at work, who, appre-
hending the fate of Sodom and Gomorrah, ran home with-
out once looking behind them. Encouraged, however, by
a woman, whose curiosity was superior to her fears, they
returned with her to the place, and brought away the stone,
which was still hot. We understand that Governor„Williams
of the Mississippi territory, now in Rockingham, intends
sending it to the Chemical Society in New York to be
analysed: it is, he informs us, of a dark brown colour,
porous, and probably contains iron.

COFFEE.

A foreign journal announces that a M. Bamas, a cloth-
manufacturer in the department of the Seine and Marne,
has succeeded in growing coffee in France. He sowed
some Mocha coffee, and obtained a produce of about 15
pounds of beans possessing the proper flavour and form.
Perhaps the most important circumstance attending this
experiment was his neither employing a green -hou<e nor
glass frames, nor any unusual shelter, but simply preparing
the soil with some care.

DE LUC'S

Electric Column . — Lectures, 3 1 7

DE LUC'S ELECTRIC COLUMN.

We have again to notice the ringing of the small bells by
means of De Luc's electric column. They were ringing on
the evening of the 24th of August, and had been so doing,
without being observed to have stopped, for a period of 152
days and a half. This long continuance renders it not im-
probable that (as was suggested in our Magazine for March)
u the weight of the clapper may be so adapted to the power
of the apparatus, as to cause small bells to continue ringing
for several "years without intermission. "

If any of our mechanical readers can suggest to us an
easy method, by which a pendulum vibrating can give mo-
tion to wheel-work, they are requested to communicate such
contrivance to us. It is much wished that an instrument
may be made, which by the motion of an index hand and
dial-plate may show the number of vibrations in a given
time, as it would be very interesting to observe what altera-
tions may take place in different states of the atmosphere.

LECTURES.

Middlesex Hospital,

Medical Lectures, 1810-11, by Richard Patrick Satterley,
M.D. Fellow of the Royal College of Physicians, Physician
to this Hospital, and to the Foundling Hospital ; and
Thomas Young, M.D.F.R.S. Fellow of the Royal College
of Physicians.

Dr. Satterley's Course of Clinical Instruction will begin
the first week in November: the attendance on the Patients
will be continued daily, and Lectures will be given once
a week, or oftener when it may be necessary, at Eleven
o'Clock. — Mr. Cartwright, Surgeon to the Hospital, will
undertake such occasional demonstrations of morbid ana-
tomy as may be required for the illustration of the respec-
tive cases. The objects of the Course will also be extended
to such remarkable peculiarities in the diseases of Children,
as may occur in the Foundling Hospital. Terms of admis-
sion, to Pupils of the Hospital, Five Guineas.

Dr. Young will begin, in February, a Course of Lectures
on Physiology, and on the most important parts of the
Practice of Physic; in particular the Nature and Treatment
of Febrile Diseases : he will deliver them on Tuesdays and
Fridays, at Seven o'Clock in the Evening. Admission,
Two Guineas : to former Pupils, One Guinea.

Those who are desirous of attending either of these
Courses, are requested to leave their names with the Apothe-
cary at the Hospital, from whom further particulars may
be known. Electrical

3 1 8 List of Patents for new Inventions,

Electrical and Electro- Chemical Science.
Mr. George Singer will commence a Course of Lectures
on Electrical Phenomena, comprehending all the new Dis-
coveries, and illustrated by numerous original Experiments.
Early in the ensuing season a Prospectus of the Plan of
Instruction may be had of Mr. Cuthbertson, 54, Poland-
street ; or of Mr. Singer, at the Institution, 3, Princes-street,
Cavendish-square.

Surry Institution.

The Annual Courses of Popular Lectures at the Surry
Institution, Blackfriars Bridge, commenced on the 15th ult.
and will continue every succeeding Monday and Thursday
Evening, at Seven o'Clock, during the Season. — The fol-
lowing Gentlemen have been engaged for the following De-
partments, viz.

Zoology George Shaw, M.D. F.R.S.

Music Mr. S. Wesley.

Zoonomy John Mason Good, Esq.

The Chemistry of the Arts F. Accum, M.R.I. A.

Natural Philosophy andl M Hardie
Astronomy J

LIST OF PATENTS FOR NEW INVENTIONS.

To Thomas Norris, late of Manchester, cotton merchant,
for his new mode of sheathing or covering the bottoms of
ships or vessels with certain matter or materials, so as to
be a substitute for copper. — Sept. 26.

To Samuel Hobday, of Woodcock-Street, in the parish
of Aston, near Birmingham, snuffer- maker, for his lever,
by the application of which alone, or with the addition of a
rack, he can make snuffers to act without springs. — Sep-
tember 26.

To Marck Isambard Brunei, of Chelsea, gent, who, in con-
sequence of a communication made to him by a certain fo-
reigner residing abroad, is become possessed of an apparatus
for giving motion to machinery; part of which is aJsq ap-
plicable to hydraulic and pneumatic purposes. — Oct. 1.

To Benjamin Milne, of Bridlington, in the county of York,
collector of the customs, for an improved bell- and gun-
alarm. — Oct. 1.

To Joseph C. Dyer, of Boston, state of Massachusetts,
one of the United States, now residing in London, mer-
chant, in consequence of a communication made to him
by a certain foreigner residing abroad, who is become pos-
sessed of certain improvements in the construction and

method

List of Patents for new Inventions. 3ig

'method of using plates and presses, and for combining
various species of work in the same plate for the kind of
printing usually called plate printing, designed for the ob-
jects of detecting counterfeits, for multiplying impressions,
and saving labour. — Oct. 1.

To George Miller, of Panton-street, near the Haymar-
ket, musical instrument-maker, for his method of making
wind instruments commonly called military fifes, of sub-
stances never before used for that purpose. — Oct. J.

To John Towill Rutt, of Goswell-street, in the county
of Middlesex ; John Webb, of Hoxton, in the said county;
and John Tretton, of the city of London, card manufac-
turers, for their improved apparatus to machines for making
fillet, sheet, and hard cards, such as are used for carding
wool, cotton, flax, silk, and all substances capable of being
carded. — Oct. 8.

To Ebenezer Parker, of Highfield^ in the parish of Shef-
field, in the county of York, silver-plater ; and Francis
Cleeley, of Sheffield aforesaid, surgeons' instrument-manu-
facturer, for their method or plan of making an adjusting
bedstead on a double frame with a four- fold method, for the
relief of sick, lame, infirm and aged persons. — Oct. 8.

To John Hazledine, of Bridgenorth, in the count v of
Salop, engineer, for his manifest improvements in the con-
struction of a plough for the cultivation of land. — Oct. 8.

To George Hodson, of the city of Edinburgh, North
Britain, ash-manufacturer, for his improved method of se-
parating the alkaline salt from the acid as it exists in the
following substances, viz. kelp, black ashes, soaoer's salts,
spent leys, sosa natrose, j-ock salt, common salt, brine, sea
water, caput mortuum of aqua-fortis, caput mortuum of
oil of vitriol, and caput mortuum of salt used by bleachers,
being on a principle entirely new. — Oct. 8.

To Charles Francis, of Phcenix Wharf, Nine Elms, in
4the parish of Battersta, Surry, temper lime-burner; and
William Waters, of Princes-street, in the parish of St.
Mary, Lambeth, Surry, potter, for their improved method
of joining pipes. — Oct. 8.

To Henry Stubbs, o,f Piccadilly, in the county of Middle-
sex, blind-maker, for his new grand imperial aulaeum, from
three to 18 or 20 feet wide, without seam, and to any length
or colour, for decorating the most super!) or useful room, for
such as drapery, curtains, and fringes, chairs, sofas, tables,
&c. or finished on one side only for ornamental hangings,
borders, and every other species of dt-joration. — Oct. 8.

METEORO-

320) Meteorology.

meteorological table,
By Mr.' Carey, of the Strand,
For October 1810.

Thermometer.

1 </5

Days of

Month.

P o

^2

a
o
o

1 *

u "So

Height of

the Barom.

Inches.

o >, o

Weather.

Sept. 27

53

68°

54°

,29*92

53

Fair

28

55

68

56

•90

50

Fair

29

51

66

56

30*01

36

Fair

30

56

64

57

29*93

30

Fair

October 1

58

64

51

30-11

30

Fair

2

55

63

52

•24

50

Fail-

3

50

64

51

•22

62 .

Fair

4

52

64

52

•25

41

Fair

5

51

64

52

•09

50

Fair

6

52

61

50

29*91

20

Fair

7

48

66

55

•98

18

Foggy

8

53

65

56

•94

52

Fair

9

54

61

55

•90

30

Cloudy

10

55

59

54

•82

30

Cloudy

U

52

59

48

•90

30

Fair

12

47

57

44

•85

55

Fair

13

40

57

43

3005

51

Faii-

14 46

56

46

•20

36

Cloudy

15

46

57

47

•19

32

Fair

16

42

56

55

29*84

30

Cloudy

17

57

62

56

'55

15

Showery

18

56

64

55

•45

35

Fair

19

50

59

58

•78

35

Showery

20

56

61

49

•68

30

Rain

21

50

59

56

•62

36

Showery

22

57

61

48

•35

48

Stormy

23

49

55

44

'57

42

Fair

24

46

52

41

•83

24

Fair

25

42

50

40

30-16

34

Fair

26

39

49

44

•35

42

Fair

N. B. The Barometer's height is taken atone o'clock.

erratum.

Pa-re 2SI, line2G from the top, (Mr. Taunton's paper on Inguinal
Hernia,)— for turned read traced.

t 321 ]

LX. Description of a Camp Telegraph, invented ly Knight
Spencer, Esq. Secretary to the Surry Institution.

To Mr. Tilloch.

Sir, Jl he important advantages resulting to the naval
service from the introduction of the telegraph by Sir Home
Popham, now universally adopted, are too well known to
be here insisted upon.

That telegraphic signals have been productive of great
advantages to land armies, for more than 3000 years, is very
easily proved.

That the most important advantages have resulted to the
French arms, from the use of the telegraph, in the present
age, is too well authenticated to be doubted.

That commanders of British armies have felt the abso-
lute necessity of adopting some mode of telegraphic com-
munication, is proved by the late campaign in Sicily, and,
the present campaign in Spain.

That many attempts have been made to introduce the
telegraph into our land-service universally, cannot be ques-
tioned.

To what cause, then, is it to be attributed, that to the
present moment this powerful instrument remains to British
armies (generally speaking) nearly a useless invention ? .

The only rational answer to this question seems to be,
that, hitherto, no practicable system has been offered, and
the attempts to introduce it must, probably, have failed; —
either, from the intricacy of the machines, or, the difficulty
of transporting them into situations where they could be
used.

Whatever cause may have hitherto retarded its intro-
duction, it will hardly for a moment be contended, that,
were a telegraph produced as certain in its operations as
the present fixed telegraph, and at the same time so sim-
ple and portable as to require no separate establishment,
either for its transport or management, it would not be a
most important acquisition in the field.

With this conviction on my mind, I have endeavoured
to obviate the supposed difficulties ; and the result, which
I call my Camp Telegraph, 1 request permission to lay
before the public through the medium of your respectable
Magazine ; — indulging the hope, that it may meet the at-
tention of those who have sufficient iufluence to bring the
subject fairly under the consideration of his majesty's^ go-
Vol. 36. No. 151. Nov. 1810. X vemment.

32^ Description of a Camp Telegraph.

vernment. Perhaps it may not be improper to state, that
my invention has already been honoured with the appro-
bation of several general and olher officers very capable of
forming correct opinions on the subject; — and that I have
frequently asked a question with it at the distance of six
miles, and have received an answer within three minutes.
Any officer of ordinary capacity will be able, after two hours'
application, to direct a station; any private will perform
the duty of a signal-man after half an hour's drill ; — and,
the apparatus not being more cumbrous than a Serjeant's
pike, there seems no necessity whatever for a separate esta-
blishment to manage it.

EXPLANATION.

To work the Camp Telegraph; which is numerical, the
director of each station must be assisted by three privates
or others, to be called signal-men ; one of whom must be
furnished with a staff 13 or 14 feet high, on which must
be mounted two flexible balls, about three feet diameter, as
described below : — this is called the centre-point. The
other two signal-men must each be furnished with a staff
ten feet high, mounted with one flexible ball.

The signals must be made by one or both of the signal-
men taking an ordeied number of paces to the right or left
of the centre-point; in the rear of which the director
takes his stand, during-the time of making communications.

All signals must be made by order of the director of the
station, who must give the word for the necessary number
of paces. These are to be taken by the signal-men, in
double-quick time, carrying their balls at the trail ; and when
they have arrived at the point or points ordered, the balls
must be instantly elevated.

All signals must be repeated by the corresponding sta-
tion; and when the director of the station making the
communication, observes this is done, he gives the word
" Down," and his signal-men n\ust then retire in double-
quick time to the rear of the centre-point, carrying their
balls at the trail. The word iC Down" must likewise be
given by the director of the station receiving a communica-
tion, the instant he observes the signal-men at the corre-
sponding station begin to retire.

A. (Plate VIII.) Is the signal of communication, and is
made by placing one of the signal-men at 20 paces to the
right, and the other at 20 paces to the left, of the centre-
point.

ft Is

Description of a Camp Telegraph. 323

B. Is the signal of a point or period, and is to be made
at the close of a number, as 275, by placing one signal-man.
three paces to the right, and the other three paces to the
left, of the centre-point.

C. Is the signal of error, and is to be made when your
correspondent has mistaken your last signal : — Suppose you
had made the signal No. 2, which is 20 paces to the right,
and your correspondent answers with 20 paces to the left,
which is the signal No. 7. Then make the signal of error,
by placing one signal-man three paces to the left, and the
other 10 paces to the right of the centre-point; and when
your correspondent has repeated this signal, thereby con-
vincing you he is sensible of his error, repeat the signal that
had been mistaken, and, if rightly answered, proceed as
before.

D. Is the repeating signal, and is to be made if the
last communication is not understood. It is' made by
placing one signal-man three paces, and the other 20 paces,
to the left.

NUMERALS.

No. 1. Is made by placing one signal-man three paces to
the right of the centre-point.

2. By placing one signal-man 20 paces to the
right.

3. By placing one signal-man 10 paces, and one
20 paces, to the right.

4. By placing one signal-man at three, and one at
five paces, to the right.

5* By placing one signal-man at 18, and one at 20,
paces to the right.

6. By placing one signal-man three paces to the left
of the centre-point.

7. Bv placing one signal-man 20 paces to the
left.

8. By placing one signal-man 10, and one 20, paces
to the left.

9. By placing one signal-man at three, and one at
five, paces to the left.

0. By placing one signal-man at 18, and one at 20,
paces to the left.

X2 The

324 Description of a Camp Telegraph.

The flexible ball is constructed in the following man-
ner :

Take an ash or deal stafFof the required length, and the
substance of a stout pike. Take twelve whalebones, four
feet six inches long, and fix them at nine inches from the
top of the staff, in the way the whalebones of umbrellas are
fixed : — fix the lower ends of these whalebones to a strong
slide (like the slide of an umbrella), the pipe of which must
be 18 inches long, and project upwards. To the top of
this pipe, stretchers 18 inches long must be affixed, and
also to the middle of each whalebone, like the stretchers of
an umbrella, to keep the ball stiff when in use. Theie must
then be a strong umbrella- spring fixed on the staff, at three
feet from the upper fastenings of the whalebones, or top of
the ball, so that, when the slide is pushed up, the whale-
bones will form a sphere of three feet diameter.

The skeleton of the ball being thus prepared, it is to be
covered with glazed linen, half black and half white, di-
vided vertically. Letter G is a drawing of the skeleton of
the ball, but only showing two whalebones instead of
twelve. When the balls are not in use, they will be un-
sprung, and covered with strong cloth cases.

SIGNALS BY NIGHT.

To make these, it will require two lamps, about nine
inches square and 12 inches high, to be elevated, one above
the other, at the distance of three or four feet, for the cen-
tre-point: and one lamp for each signal-man, to be fixed
on the top of the ball -staff.

Each lamp must have two hollow lenses, about four inches
diameter, filled with different-coloured transparent fluids —
(say pale green and pale red), — which will distinguish them
from common lights. % They must be suspended upon a pin,
put through a strong iron frame, resembling the frame of a
sign which is fixed upon an upright sign-post, so that when
the staff is raised they will -swing perpendicularly; and
when, they are carried at the trail, they will still be in a per-
pendicular position.

The reservoir for the oil must be made like those for the
agitable lamps; the wicks must be flat, and about one inch
broad.

£. is a front view of the lamp for night signals.
r. is a side view of the same.

A code of numerical signals, and a numerical vocabulary

applicable

Charges of greatest Efficacy for Artillery at Sea. 325

applicable to the land service, arranged upon the plan of Sir
Home Popham's tor the naval service, will be necessary.

When a tent or any other object is fixed upon as a cen-
tre-point, it is then generally unnecessary to use the double
ball.

When stations are taken below the horizon, the white
sides of the balls are to be turned to your correspondent,
and it is advantageous to have the men in white cr fatigue
dresses.

When stations are taken above the horizon, the black
sides are to be turned towards your correspondent, and then
it is advantageous to have the men in uniform.
I am, sir,

Your obedient servant,

Surry Institution, KNIGHT SpENCER.
Nov. 6, 1810.
x..: 7 ..':,-, • ■ ■'■'■ '■.' : ' ': < ■ r

LXI. On the Penetration of Balls into uniform resisting
Substances. By W. Moore, Esq.

To Mr. Tilloch.

Sir, Ohould the following paper on the destruction of
an enemy's vessel at sea by artillery be thought deserving
a place in your excellent Magazine, you are at liberty to
make use of it accordingly.
I am, sir,

Your most obedient servant,

Royal Military Academy, W# MOORE.

Woolwich, November 10, 1810.

Lemma I.

If two spheres of different diameters and different specific
gravities impinge perpendicularly on two uniform resisting
fixed obstacles, and penetrate into them ; the forces which
retard the progress of the spheres will be as the absolute re-
sisting forces or strengths of the fibres of the substances
directly, and the diameters and specific gravities of the
sp h eres i n ' crse ly .

Lei R and r denote the absolute resisting forces of the
two substances ; F and/ the retardive forces ; D, d the dia-
meters of the spheres; O, q their quantities of matter,
and N, n their respective specific quantities. Then the
whole resistances to the spheres, being bv mechanics pro-
portional to the quantities of motion destroyed in a given
time, will be as the absolute resisting forces of the sub-

X 3j§ stances

326 Charges of greatest Efficacy for Artillery at Sea.

stances and quantities of resisting surfaces jointly ; or as
the resisting forces of the substances and squares of the

M R D*

diameters of the impinging spheres : that is, — = — x -=>
r o o i ' m r <r

But in general — = — x — : therefore equating these

F
two values of the whole resisting forces, we obtain -j- x

Q R D* , F R D* a

= — x —pr, and — r- = — x -jt- X ~Ir • and since

q r d* f r d* Q,

Q ~ IP X N > lt 1S / ~ r X 2*~ X B» X "N" "" 7~ X

■q x ^: that is, the forces retarding spheres penetrating

uniform resisting substances are as the absolute strengths
of the fibres of the substances directly, and the diameters
and specific gravities of the spheres inversely.

Lemma II.

The whole spaces or depths to which spheres impinging

on different resisting substances penetrate; are as the squares

of the initial velocities, the diameters and specific gravities

of the spheres directly, and the absolute strengths of the re-

j ■ . , S V3 D N r

sis ting substances inversely : or, — = — r X —7- X — - X ^r.
J ' s v* d n R

For by mechanics we have — =-rxi; and by the
J s . v% F " J

f r D N

preceding lemma ~- == — x— t- X — , which substituted

c MX a n

.... S V2 D N r

m the above it becomes — = —r- x — r x — x -rr»
s v* d 11 R

These being premised, I now proceed to resolve the fol-
lowing most important

Problem :

To find a general formula which shall express the quan-
tity of charge for any given piece of ordnance to produce the
greatest destruction possible to an enemy's ship at sea; it
being supposed of oak substance of given thickness, and at 4
distance not affecting the initial vtlocity of the shot.

t> x u 11 v* s d n

By Lemma 2, we have, generally, —f = — x if x N X

■ — . Also the charges of powder vary as the squares of the

% velocity

Charges of greatest Efficacy for Artillery at Sea. 327

velocity and weight of ball jointly*. Hence, since it has
been determined from experiment that a charge of half a
pound impelled a shot weighing one pound with a velocity
of lo'OO feet per second ; we shall, considering V the velo-
city of any ball impinging on the side of the vessel, have
for the expression of the charge impelling it through the
_ $dnRv*w

sPaceS-2Di^x^r

Now to apply this in the present instance, it is first ne-
cessary that a case be known concerning the penetration
of a given shot into oak. Such a case is presented at
page 273 of Dr. Hutton's Robins's New Principles of
Gunnery. It is there asserted that an 18-pounder cast-iron
ball penetrated a block of well-seasoned oak, such as ships
of war are generally built with, to the depth of 2>\ inches
when fired with a velocity of 400 feet per second. Making,
therefore, this the standard of comparison for all cases where
the object is of oak substance, we shall have for the charge

7. 400* x *42 SnRw .

generally =- x -^ — ; or, because the balls

2xi600*x ir

24

are of the same specific gravity, and the substance the

j tvt • -n u 400* X '42
same, or R = r, and N = ra; it will be — x

2xi6Wx —

— - == '045 x — ,y ; that is the charge vanes as the space

to be penetrated and weight of ball directly, and diameter
of the ball inversely.

But the charge by the question being to produce the
greatest effect possible in the destruction of the vessel; S
in the above formula must always be put equal to the given
thickness of its side plus the radius of the ball; since it is
well ascertained that, for a shot to produce the most damage
to any splintering object, such as oak; it must lose all its
motion just as it quits the superior or further surface of it.

-ft , » . • (S-r4DW '

Hence the charge in question is =«045 x — . o

being the thicknes of the side of the vessel, iu the weight
of the ball, and D its diameter.

We have supposed, that the resistance opposed to the
( ball's motion is uniform throughout the entire penetration;

* This law of variation of the char -rei does not exactly obtain in practice
after a certain charge, on account of the definite lengths of the guns: but it
is presumed the deviation from it, if known, would not materially affect
pur re.su Its,

X 4 which

328 Charges of greatest Efficacy for Artillery at Sea.

which is not strictly true; since that resistance depends
partly on the quantity of the surface resisted, which con-
tinually varus until the ball has penetrated to the depth of
This; when it continues uniform till it arrives at the
fu h r surface of the object; where the resistance a^ain
co nuitncea ts variation. These deviations from uniformity
are about sufficient to set against that of the law of variation
of the charges before mentioned; the velocities from them
filing somewhat :>hort of the law there prescribed after a
certain charge.

Example I.
An enemy's ship is in sight ; required the charge for the
42 pounder guns to destroy her as quickly and completely
as possible when the ships have approached near to each
other: the side of the enemy* s vessel (a seventy four) being
1*. foot thick of' oak timber.

The diameter of a 42-pounder of cast-iron being ='557

foot; we get '045 x - £-- - = 6'8S306lbs,

D

or

6lbs,

14ozs. for the weight of the charge required.

TABLE

Containing the various charges for the 12-, 18-, 24-, 32-,
36- and 42-pounder guns, for producing the greatest
effect in all cases of action : the substance or object being
of oak materials, and its thickness together with the ra-
dius of the ball from 1 foot to that of 5 feet, regularly
increasing by 1 in the inches.

' Nature

of
Ordnance.

Thickness of the Side of the Vessel, plus the
Radius of the Ball.

12 Inches.

13 Inches

14 Inches.

15 Inches.

Pounder
12

lbs.
1-439242

lbs.
1-559178

lbs.
r6791l6

lbs.

1 -799052

18

l'92S57l

2-089285

2249999

2-410714

24

2336650
28304/0

253137J

2726O9I

2'920813

32

3 066343

3302215

3538088

36

3061630

3 3 I6766

357IQOI

3 827038

42

3-303180

3 675949

3-95S710

4241475

Charges of greatest Efficacy for Artillery at Sea. 329

Nature

of

Ordnance.

Thickness of the Side of the Vessel, plus the
Radius of the Ball.

16 Inches.

17 Inches

18 Iuches.

19Liches.

Pounder
*, 12

lbs.

1'9189S7

lbs.
2838926

lbs.
2-158863

lbs.
2278800

18

2*57 1 428

2732142

2892856: 3053571

1

24

3 115533

3 310254

3 -504975-j 3-699696

32

3773960

4009833

4-245705 4-481578

36 4-082 173

4-337310

■4-592445! 4-847581

42

4524240

4806905

5089770 5372535

1

20 Inches.

•21 Inches.

22 Inches.

23 Inches.

1 lbs.
12 2-398737

lbs.
2518674

lbs
2-638612

lbs.
2*758547

18 3214285

3 374999

3-535714

3 696428

24 3-894417

4089 137

4283859

4478580

32 47l7.i50

4953323

51 89195

5 425068

36 51O2717

5'357353

5 612988

5-868124

42 ! 5655300

5 '938065

6-220830J 6-670262

24 Inches.

25 Inches.

-0 Inches

11 Inches.

12

lbs.
2-878484

lbs.
2*998420

1 .
3118358

lbs.
3-238292

18

3*857142 4017856

4rl78570

4-339284

24

4-673 00 4868021

5 062741

5 257463

32

5 660940 5-896813

6 132085

636855Q

36

6123260 6 378396

6; 633531

6-888668

42

678636O 7 069125

7-351890

7'6o4(555

330 Charges df greatest Efficacy for Artillery at Sea.

Nature

of

Ordnance.

Thickness of the Side of the Vessel, plus the Radius
of the Bali.

-2H Inches.

vy Inches.

30 Inches, j 31 Inches.

1'ou iUe.-
1 2

lbs
3'358228

lbs. I lbs
3478164 ! 3-598100

lbs.

3718036

18

4*521340

4 682054

4-842768
5841626

5 003482

24

5452184

5'046gO5

6036347
7-312051

32

6504432

5-840305 i 7076! 7&

36

7' 143804

739S940, 7654070

7909212

42

7917420

8 200185 ; 848295C

8-765715

32 Inches,

33 Inches.

34 Inches.

35 Inches.

12

lbs
3 S3 7972

lbs.
3-957908

lbs.

4-077844

lbs.

4-197780

18

5'l64196

5 324910

5*485624

5 646338

24

6231068

6 425789

6 620510

6-S15231

32

7-547924

7783797

8-019670

8-25.5543

36

8 1 64348 .8-4194841 8 674620

8929756

42

9048480

9331245 | 9614010

9S96775

36 Inches.

37 Inches. | 38 Inches.

39 Inches.

12

lbs.
4-317716

lbs
4437652

lbs.
4-557588

lbs.
4-677524

18

5 80/052

5967766 6T284SO 6-289194

24

i 7 009952

7 204673 7 399394

7 594115

32

| 8-491416

8-727289

8-9631 62 1 9-199035

36

! 9-184892

9 440028 | 9-695164

9950300

42

io- 179540

10 462305 j 10 745070

11027835

Charges of greatest Efficacy for Artillery at Sea, 331

Nature

of

Ordnance.

Thickness of the Side of the Vessel, plus the Radius
of the Ball.

40 Inches.

4i Inches.

42 Inches.

43 Inches.

Pounder
12

. lbs.
4797460

lbs.
4917396

lbs.

5-037332

lbs.
5*157268

18

6449908

6610622

6771336

6932050

24

7788836

7933557

8-178*78

8-372999

32

9-434908

9-67078 1

9906654

10 142527

36

10-204436

10-460572

10-715708

10970844

42

1T3 10600

11'593365

11-876130

12-158895

44 Inches.

45 Inches.

46 Inches.

47 Inches.

12

lbs.
5-277204

lbs. lbs.
5-397140! 5517076

lbs.
£•637012

18

7092764

7*253478 7414392

7'574go6

24

8-567720

8762441

8957162

9-151883'

32

10378400

10-614273

10*850146

110860 19

36

11-225980

H'481116

1T736252

11-991338

42

12 441660

12-724425

I3OO719O

13-289955

j 48 Inches.

49 Inches.

50 Inches.

51 Inches.

12

lbs.

5-756948

lbs.
5-876884

lbs.
5-996820

* lbs.
6116756

18

7-735620

7'896334

8057048

8 217762

24

9*346604

9541325

9736046

9-930767

32

11-321892

IV55/765

H'793638

12029511

36

12246524

12501660

12-756796

13-011932

42

13572720

13855485

14-138250

14*421015

332 Charges of greatest "Efficacy for Artillery at Sea,

of

■

Thickness of (.he Side of the Vessel, plus
the Radius of the B .ill

52 Inches.

* 53 laches, j 54 [j ches.

•

Pound ei
12

lbs.
6236692

lbs. 1 lbs
6356628 6 476564

18

8*373476

8*539190! 8*699904

24

10125488

10*320209 i 10*514930

32

12265384

li'501257 j 12737130

36

13-267068

13*522204 13*777340

42

14703 7 80

14*986545 i 15*269310

55 Inches.

56 Inches

57 Inches.

12

lbs.
6-596500

lbs.
6-716436

lbs.
6*836372

18

8 86061 8

9*021332

9*182046

24

IO70965I

10 904372

11099093

32

12*973003

13 20S876

13-444749

36

14*032476

14*287612 1 14*542748

42

15*552070

15*834840 | 16*117*505

58 Inches.

59 Inches.

60 Inches.

12

lbs.
6*956308

lbs.
7076244

lbs.
7-196180

18

9*342760

9*503474

9*664188

24

11*293814

11*488535

11*683256

32

10680622

13 916495

14*152368

- 36

14*797884

15 053028

15*308156

42

16*400370

16*683135

16*965900

In

Charges of greatest Efficacy for Artillery at Sea. 333

In this Table the first column contains the nature, of the
ordnance, and the numbers in the other columns are their
respective charges of gunpowder in pounds, when the thick-
ness of the object to be destroyed is as specified at the top
of the columns. If the thickness be given in inches, and
parts of inches, tike such parts of the difference between
the charge for the given number of inches and the next
greater; and add them to the charge first found for the
given number of inches for the charge required.

The value of the decimal part of each will be had by
multiplying it by 16, the number of ounces in a pound, and
pointing off in the product from the right hand towards the
left, as many places for decimals as are contained in the
given decimal, and retaining the number on the left of the
point for the ounces, increasing it by |, 4-, -f-, or 1, when
the first figure of the decimal is 2, 5, 7 or 8 respectively.
This hint is merely given for those practitioners who may
not be very conversant in decimals.

Scholium.

This question is not only of the utmost importance and
practically useful in naval engagements, but in several in-
stances also of military operations; as the bursting open
gates of besieged cities with promptitude and effect, and
breaking up all fortifications composed of wooden materials;
especially those of a splintering nature, to which the above
charges apply most correctly. In the case of a naval
action where the object to be penetrated is of oak sub-
stance, the ball by having a small motion when it quits
the ship's side tears and splinters it excessively, breaking
away large pieces before it, which are not so easily supplied
in the reparation : whereas on the other hand, if the shot
had any considerable velocity when it quilted the side, the
effect produced would be merely a hole, which would be
stopped instantly by the mechanic employed for that pur-
pose; and indeed in a great measure by the springiness of
the wood itself; for I have seen in his majesty's dock-yard
at Woolwich, captured vessels, having a number of shot-
holes in them, almost entirely closed by the wood's own
efforts; and that required nothing more than a small wooden
peg or a piece of cork to stop them up perfectly: all the
damage, therefore, the shot can do under such circumstances
of swift celerity is merely killing those men who may chance
to stand in the way of their motion.

If any object to be destroyed be so thick that it cannot
be completely pierced by- any common engine; or if it be

of

334 Charges of greatest Efficacy for Artillery at Sea.

of a very brittle nature, such as stone or brick, then that
charge is to be used which will give the greatest velocity to
the shot to produce the maximum effect. But in many cases
of bombardment this charge is by no means to be preferred;
for though the effect produced each individual time be

freater, yet in any considerable time the whole effect would
e less than that from a smaller charge oftener fired, on ac-
count of the extreme heat it would give to the engine after
a few discharges; and in consequence of which greater time
would be required for cooling the gun and preparing it for
further service.

Example II.

Required the charge for a 24-pounder shot to burst open
the gates of a city with the greatest ease possible, they be-
ing o/'elm one foot thick.

Here the object to be penetrated being elm, the small

. , , c , Sdv*w f (& + ZD)dv*w\

letters in the general formula -=r ~— -[ = ----- --- _ . :

6 2Ds x i ooo* v 2Ds x l600a /

must be made to denote the several numbers of some ex-
periment made in the penetration of this substance. Taking,
therefore, the experiment of Dr, Mutton contained in the
5th problem of his elegant Exercises on Forces, we have

d— — ft. v = 1500, and S = — ft.; also by the question

S = 1 ft. D = -46, and w = 24 lbs. therefore *^°?f!^
1-23x1x1500^x24 830'25 „ ., t.

= ^ — tS ~t, — ,>™« = txt^t = 4-33S6slbs. or 4lbs.

2 X '46 x \ j X 16W IQI'36
S^ozs. nearly the weight of the charge required in this case.
Retaining the experiment of Dr. Hutton as a standard for
all cases where the substance to be penetrated is of elm, we

shall have by reduction ^-^ ='0676 x — £- - :

the charge for any piece the diameter of whose shot is D,

and weight w, S being the thickness of the object as be-
fore.

It is not unworthy of remark, that the gates of a besieged
place, or any like things, might be effectually broken open
by the gun itself, charged only with powder; by placing it
close to the gates with its muzzle from them; the mo-
mentum of recoil being generally sufficient to force such
objects completely.

LXII. Cases

[ 335 ]

LXII. Cases illustrating the Effects of Oil of Turpentine in
expelling the Tape-ivorm*.

Case U.

By Thomas Hancock, M.D.F.M.S., Physician to the

Finsbury Dispensary .
[Concluded from p. 308.]

JL have used the ol. terebinth, in only one case of taenia.
Jane Woodward, a poor woman, about 45 years of age, first
applied to me at the London 'Electrical Dispensary, some
months ago. She had been for more than seven years af-
flicted in a very distressing manner with this complaint,
and was four times a patient in different hospitals; where,
by the use of active remedies, she obtained temporary relief
from pain, and frequently voided large portions of the taenia
per anum. So soon as she had recovered a little strength,
by indulging her appetite, after the violent operation of
purgatives in these hospitals, her abdomen began to increase
considerably in size, and small detached portions of taenia,.
about an inch or more in length, apparently endowed with
life, continued to pass at times through the rectum; so
that she was prevented from earning her bread, by this very
distressing circumstance. She had generally recourse to
purgatives on these occasions, and their operation had re-
gularly the effect of reducing the size of the abdomen; but.
her disease continued. I may also observe, that, after these
courses of medicine, she had less of rumbling in the intes-
tines, and felt less pain, than when she freely indulged her
appetite ; for then, to use her own expression, " the worms
appeared to gain strength, " according to the increase of her
own strength.

About two weeks after the application of electrical sparks
to the abdomen, she discharged a portion of taenia, seven
yards in length, without any appearance of head, which
lived in cold water nearly three hours after its expulsion.
Mr. Chamberlaine informs me he has known the taenia live
nearly as long in water which was much above the tem-
perature of the human body; a sufficient proof of the ex-
traordinary tenacity of life in this animal.

Electricity was continued for some weeks longer; but as
her pains also continued, and no more of the worm came
away, my friend Mr. Chamberlaine kindly offered to try the

* From Transactions of the Medical Society of London, vol. i. part I. just
published.

effect

336 Expulsion of Tcenia ty Oleum Terelinthina.

effect of his electuary of the dolichos pruriens. The pa-
tient took this at first without, but afterwards with, the
scobs stanni in large quantities, and for a considerable time:
but though, as she asserted, these medicines, more than any
she had ever taken, relieved her sufferings, they produced
no discharge of taenia.

I now heard of the ol. tereb. having been administered
in this complaint, and resolved to give it a fair trial, espe-
cially as my patient was herself very anxious to use any re-
medy that promised the slightest probability of success.
I may premise, that her abdomen was enlarged as formerly,
her stools slimy, and, in short, all her symptoms indicated
that she had still large portions of taenia in her intestines.
I ordered her at first small doses of this oil, viz. two drachms
twice a day, mixed with treacle to disguise its taste. This
produced no other effect than an increase of pain and un-
easiness, and particularly on going to stool, as if it irritated
the rectum. The dose was now increased to half an ounce,
at longer intervals. The first dose in this quantity, which
she took without treacle, produced a little sickness and
confusion of ideas, and afterwards operated as a purge. She
complained of no uneasiness whatever in the urinary or-
gans. After these doses, she passed such a quantity of slimy
mucus, with such relief in all her painful symptoms, that
she earnestly entreated I would allow her to take a double
dose. The quantity of an ounce, which she now took, al-
ways produced a great degree of giddiness, as if she was in-
toxicated, which came on shortly after taking it, and con-
tinued for an hour or more, until the violent cathartic effect
which followed, removed it.

Although tins medicine was repeated, after this manner,
every two or three days for a fortnight or more, by her own
particular desire, there was no appearance of taenia in her
stools. I could not, however, but observe, that the mucus
which was discharged so abundantly by the operation of
the ol. tereb. sometimes exhibited the appearance of white
films, as if the substance of the worm had been broken
down. She took the very large dose of an ounce and half
two or three times, afier the medicine began to lose its
effect, with results similar to those I have described. In
short, by her own account, violent purging was the only
thing that relieved her; and all kinds of strengthening re-
medies, as well as nourishing diet, uniformly increased
her sufferings, so that she abstained from food when her
appetite craved it, in order to avoid the anticipated pain.

I have since heard that she went into the London Hospital,

and

Expulsion of Taenia by Oleum Terelinthince. 337

and had again taken the ol. tereb.; for I strongly advised
her to discontinue its use some time before she left the Fins-
bury Dispensary, having lost all hopes of its ultimately
curing her.

Case Til.

By Samuel Fotiiergill, M.D.F.M.S., Physician to the
Western Dispensary .

A soldier, aged about 40, applied to the Western Dis-
pensary, the 28th of October 1809. He stated that he had
been subject to tape-worm during the last four years, pre-
viously to which he had served with the army in Egypt,
and attributed the origin of his complaint to the badness of
the water which he drank in that country. He is now a
private in the Middlesex militia. He complains of gnaw-
ing pains in the abdomen, irregular appetite, debility, and
anxiety. He is somewhat emaciated, and his complexion
is rather sallow. Whilst with his regiment, he had occa-
sionally taken, by order of the surgeon, a variety of worm-
medicines, and small pieces of tape-worm were passed at
times; they even sometimes came away alive, without me-
dicine having been taken, and without a stool.

I directed him to take pulv. scammon. cum calomel. 9j.
every third morning. Two doses operated freely, but only
a few very short pieces of tape-worm were brought away.
I now directed him to take half an ounce of the oil of tur-
pentine. He took it as ordered, November 9, in a little
tea, sweetened with honey. In a quarter of an hour he was
seized with retching, and in the course of the day passed
four copious stools, in one of which was a tape-worm of
several yards in length. The portion which the patiant
brought me I found measured four yards ; he threw the
smaller pieces away ; but thought that altogether the length
might be ten yards. The worm was dead, and had a livid
appearance: the patient remarked that the pieces which
formerly passed from him were of a whiter colour and
brighter aspect.

The dose of the medicine was increased to six drachms,
and was repeated twice a week for the space of a month.
During the first fortnight small pieces of worm continued
to pass away, both after taking the medicine and at other
times ; but in the second fortnight the stools were natural,
and contained mo vestige of taenia. The remedy was con-
sequently discontinued j and the man called some weeks
afterwards to acquaint me that he had remained entirely

Vol. 36. No. 151. Nov. 1810. Y free

338 Expulsion ofTcenia ly Oleum Terebinthince .

free from all symptoms of his complaint, and had regained
his strength and cheerfulness.

He was generally a little sick after taking the medicine,
and for a day or two was affected with a severe pain in the
back part of his 4iead, but complained of no other unplea-
sant effects from its use.

Cases IV. and V.

By George Birkbeck, M.D.F.M.S., Physician to the
General Dispensary .

Dr. Birkbeck stated to the Society that he had admini-
stered the oil of turpentine, successfully, to two middle-aged
females who had long been troubled with the tape- worm.

In the first case half an ounce was given : no unpleasant
sensation occurred whilst it was swallowed, but consider-
able confusion of ideas and vertigo, with a slight degree of
nausea, were soon produced. In a short time a discharge
from the bowels took place; this was quickly followed by
another, with which more than four yards of the worm
were evacuated. The patient, in consequence of the fre-
quent spontaneous escape of small portions of taenia, and
the expulsion of a larger quantity about twelve months be-
fore by an active purgative medicine, had an opportunity of
comparing the ordinary appearance of the vvorm with that
which it now presented. Instead of being whitish, smooth,
full, and in motion, she represented it to be dark-coloured,
shrivelled, filmy, and lifeless. A second dose of the oil
did not expel any more of the worm, nor, when he last saw
her, about three months afterwards, had it again appeared.
In that interval she had not been disturbed by any of the
unpleasant feelings to which she was before subjected.

Considerable derangement of the general health and great
pain in the pit of the stomach were produced by the tape-
worm, in the second case in which the oil of turpentine
was employed. Although one tea-spoonful only was in-
troduced, sickness and acute pain followed: this dose was
repeated several successive mornings, always with the same
immediate effects; but occasionally it was succeeded by
the expulsion of large portions of the worm. The worm
was represented to have the appearance before noticed. The
patient had sufficient resolution and confidence to continue
for some time the use of the medicine, and at length be-
came free, not only from any further appearance of taenia
in the stools, but iikewise from all those sensations which
had so long denoted its presence in the intestines.

Case

Expulsion of Tcenia ly Oleum Terehinthince. 339

Case VI.
By James Saner, Surgeon, F.M.S.

A woman, about 40 years of age, came to me in May
last, very much agitated, having just voided about six or
eight feet of tape- worm. She told me, that pieces had
come away for the last seven years whenever she took a
dose of jalap, which she had done that morning. She ne-
ver found any thing to relieve her so much as the jalap,
though she had taken a great deal of medicine from respec-
table practitioners, and had also been under the care of a
noted empiric for two years.

Ithought this a good opportunity for trying the ol. tereb.
rectificat. I therefore gave her one ounce with an equal
quantity of syrup of saffron. In less than two hours she
returned to me with about eight feet of the worm, with
the head attached. She was very much gratified by this,
as she had been told to look for the small black head. The
medicine did not produce any unpleasant sensation; merely
a slight degree of nausea, a giddiness as if intoxicated, and
a frequent desire to void urine, though without pain.

The day after, she complained of a feeling of emptiness
in the stomach. I gave her the decoct, cinchonae for a few
days, which completely removed the sensation, and she has
remained perfectly well ever since.

P.S. — The woman informed me she used to eat raw meat
formerly, as it seemed to ease her stomach more than any
thing else; but since she voided the worm, she has had no
craving for it.

Case VII.

By the same.

Since communicating the above, I am sorry to say I hays
had a case of taenia, where the ol. tereb. rect. has not so
completely answered my expectation.

Being very sanguine in my opinion of it, in consequence
of my former success, I mentioned the case to a relation of.
mine, who informed me he knew a labouring mechanic (a
Russian) who had voided large pieces of tape-worm for a
number of years. He persuaded this man to visit me, and
I gave him the same dose I had given my former patient.
It brought away a very large quantity, but so very soft that
I could not measure it. As I could not perceive any thing
like the head of the worm, I advised him to repeat the dose
in a few days, which he very readily complied with, as he
had suffered very littie from the first.

Y 2 I gave

340 On "Refraction,

I gave him the same quantity as before (viz. ol. tercb.
rect. et syr. croci aajj). This produced violent retchings,
tenesmus, strangury, and great pain in the back ; the urine
was also a little tinged with blood. The strangury and
tenesmus continued nearly a week, and the patient was not
able to work for several days after. As he had not voided
any portion of worm with the last dose, I concluded that
he was quite well, but requested he wou4d call on me again
in about two months. He called last week, and T advised
him to try his old remedy (a drachm of jalap), which had
its usual effect, in bringing away a large quantity of the
worm. I fear I shall not be able to induce him again to
try the ol. tereb., from the severe symptoms which U pro-
duced when he last used it.

Aug. 27, 1810.

LXIII. A short Account of the Improvements gradually
made in determining the Astronomic Refraction, By
T. S. Evans.

X he principal object which the astronomer has in view,
is to determine the real places of the heavenly bodies, from
the apparent ones observed from a point situated on the
earth's surface. In general, it is necessary to reduce them
to what they would have been found, were the observer
situated in the sun's centre : and it is very seldom that they
do not require to be reduced to some other point. Various
equations and corrections are of course necessary for this
purpose, but none of greater importance than the refraction,
which is caused by the atmosphere that surrounds the earth,
and produces in' every ray of light that traverses it, a greater
or less deviation from its rectilinear course, according to
the density of the air, and the altitude of the object above
the horizon. Perhaps there is nothing that has opposed so
great an obstacle to the improvement of astronomy as re-
fraction, and nothing requires greater attention by every
one who makes observations of any accuracy, since there
are very strong reasons for presuming that it is different,' in
some degree, in almost every different situation. Most of
the principal astronomers from Tycho Brahe down to the
present time have done something which tended to improve
the method of finding it : but further observations and
experiments are still wanting, for there is, even now, an
uncertainty of several seconds in it, at low altitudes. To
bring under one point of view, aud in the compass of a small

sketch,

On Refraction. 341

sketch, the various endeavours of these illustrious men, is
the humble attempt or this short essay ; which, it is hoped,
will have the desired effect of stimulating others, who pos-
sess the means, to the consideration of the subject, that
we may shortly be enabled to discover its quantity with the
greatest accuracy, at all altitudes, and under all changes of
the atmosphere.

There appears to be but little doubt that the astronomic
refraction was known to the ancients, since it is expressly-
mentioned by Ptolomy, although not made use of in his
calculations *. He says, near the end of the eighth book of
the Almagest, that in the rising and setting of the heavenly
bodies there are changes which depend upon the atmosphere:
and he mentioned it more at length in a work on optics
which unfortunately has not been handed down to usf .

Alhazen, an Arabian writer, who is generally supposed
to have lived about the vear 1100, and to have taken the
greater part of his optics from the works of Ptolomy, speaks
also decidedly of it, and shows the manner of convincing
ourselves o its existence by experiment J.

" Take/' he says, "an armillary sphere which turns round
its poles, and measure the distance of a star from the pole of
the world when it passes near the zenith in the meridian,
and when it is rising or setting near the horizon, and you
will find the distance from the pole less in the latter case."
He then demonstrates that this must arise in consequence
of the refraction, but he does not state its quantity.

In the collection of observations made by Bernard Wal-
ter, published by Willebrord Snell, in the year 1618, it is
stated, the observations were so exact that they pointed out
to Walter the quantity by which the altitudes of the stars
and planets were increased on account of the refraction.

TychoBrahe§, however, appears to have been the first
who asserted, with any degree of accuracy, that the refrac-
tion elevates the heavenly bodies rather more than half a
degree when in the horizon. But either his instruments or
his observations were not sufficiently correct to determine
it with certainty for all degrees from the zenith to the ho-
rizon : and accordingly where these failed the rest was sup-
plied bv conjecture. He believed that the sun's refraction
was 34' in the horizon, and that it became insensible at 45°
of altitude. For the stars, however, he assumed an en-

* La Lande's Astronomy, 2163, 3d edit. Encyciop. Yverd. art. Rrfrnctivn.
Encycl. Mcth. do. a

+ Lh Lande's Astronomy, as above. Smith's Optics, p. 58. Remarks.
Friestley's Hist. Opt. 4to, p. 18.

\ Encyciop. Yverd. art. Refraction. § Progymn. p. 15.

Y 3 tirely

342 On Tie fraction.

tirclv different quantity, viz. 30' in the horizon: but this,
according to him, terminated at only 20° of altitude*.

The following is the manner in which it is related that
Tycho made this discoveryf. He had determined with one
or two instruments, extremely well made, the latitude of
the place, by observations of polaris above and below the
pole. He determined it also by the sun's altitude in both
solstices, and found it four minutes less by the latter. At
first he doubted the goodness of his instrument, and there-
fore constructed with the utmost care as many as ten others
of different sizes and forms, but they all gave nearly the
same result. He could no longer attribute this difference
between the two determinations of the latitude to any de-
fect in the observations, and therefore endeavoured, by an
attentive consideration of the subject, to find out the cause
of this curious phenomenon. At length he supp- sed it
could only arise from the refraction, which elevated the
sun at the winter solstice, having then only 11° of altitude
above the horizon. This conjecture agreed very well with
the principles of optics ; but still Tycho Brahe could
scarcely persuade limself that the refraction was sufficiently
large to produce so great a difference : on this account he
made other instruments of ten feet diameter, whose axis
corresponded exactly with the pole, of the world; and with
these he measured the declination of the stars out of the
meridian %. He thtn found, that even in summer, the re-
fraction, although insensible at the meridian altitude of the
sun, was very considerable near the horizon ; and that the
defect was about half a degree in the horizon,

A copy of Tycho Brahe s Table§ of Refrac-
tion for a star is given in the margin.

In this state did the refraction continue for
many years. Even Riccioli || in 1665 sup
posed it nothing at about 26^ of altitude :
but he thought the moon had only 2?/ of
horizontal retraction in summer; the sun 30',
and the stars 30' 3 7".

* Mem. de PAcad. av. s. renouv. torn. v. p, 82. Long'* Astronomy, vol. i.
p. 254, where a comparison is given of his Table with those of Newton and
Flamsteed. f Encycl. Method.

X The greater part of these very curious and ingenious instruments are
given in his j&slronom\ce instaurata Mcchanica, printed at Wandesburg in
1598. This work is now become extremely ran- , and to be met with only
in a few of the great public libraries : on which account M. Jeaurat had
the plates engraved again upon a reduced scale, and published in the Me-
moirs of the Academy of Sciences or%>ari5 for the year 17(>3, p 120.

§ Progymn. p. 79. 104. Street's. Astr. Carol, p. 119. Long's Astr. vol. j.
p. 254. Maria Cunitia Urania Propitia. p. 286, fol. 1(350.

(| Astr. Reformat. Astr. ref. Tabul. p. 47. Iv

Alt.
0J

Refract.

30' 0"

1

ll 1 -30

2

15.30

3

12-30

4

11-00

5

10-00

On Refraction.

It was not till after the year 1672, that a
tolerably near table of refraction made its ap-
pearance, when the elder Cassini took the
subject into consideration*. What led to
this was the voyage of Richer to Cayenne in
that year, upon the utility of which some
very excellent remarks were made by Cassini,
showing how far observations made in a situ-
ation so near the equator tended to confirm
or disprove certain theories derived from
observations made in Europef. Several very
useful deductions were drawn from a com-
parison of those made both at Paris and Cay-
enne; among others the refraction was set-
tled upon more accurate elements than here-
tofore |, and a new Table computed, for the
first time, of its quantity for all degrees, up
to the zenith ; an abridgement of which is
given in the margin.

From the relation of his grandson, it ap-
pears, however, that Cassini had at one time
computed three tables of refraction for all
altitudes : one for winter, another for summer,
and a third for spring and autumn : but several
doubts having been suggested to him re-
specting this arrangement, although in ap-
pearance conformable to nature, and princi-
pally the observations of Richer at Cayenne,
where the refraction was found little dif-
ferent from that at Paris, he changed his
opinion ; and, judging that since the great
difference of heat of the torrid zone, from
that of the temperate, which we inhabit,
does not cause sensible differences in the re-
fraction ; therefore, the greatest heat or cold
of our climate could not change it much ;
and he then fixed upon one table, which was
that used by the astronomers of the Royal
Observatory of Paris, up to the vear 1745 §.

It was alwavs thought, before the time
that the refraction did not extend its

343

Table continued.

Alt.
0°

Refract.

30' 0"

6

90

7

6-15

8

6-45

9

60

10

5*30

11

50

12

4-30

13

4-0

14

3*30

15
16

3'0

2*30

17

2*0

18

1-15

J9

0*30

20

O'O

Alt.

Refract.

0

32-20

1

27*56

2

21- 4

3

16- 6

4
~5

12*48

10-32

10

5-28

15

3 36

20

2-39

30

1-42

40

1-10

45

0 59

50

050

60

0-34

70

0-21

80

0-10

90

o- 0

of Cassini,
influence higher

* Mem. de 1* Acad, avant son renouv. torn. v. p. 81.

+ In the observations of Picard made in various parts of France, in the
year 1674, there are several for ascertaining the retraction; and a table is
given from them for each degree of altitude up to 22°. — Mem. deVAcud. av.
fonreimuv. torn. iv. p. 111.

X Mem. del" Acad, avant son renouv; torn. v. p. 105. § Ibid. 1745.

Y 4 than

344 On Pefraction.

than 45° of altitude : and he is generally considered as
the first who proved that it reached all the way to the
zenith*. He also supposed that near the equator the
horizontal retraction was less than in our climate by
about one-third ; that this difference decreased as far up
as 60°, after which it was the same nearly for both cli-
mates.

From this discovery it followed, as a natural conse-
quence, that the refraction must be greater near the pole
than at Paris : and this was shortly afterwards proved to
the Academy by the publication of a work expressly on
that subject f. The king of Sweden, being in 1694 at
Tornea in West Bothnia, near the latitude of 65° 45', and
observing that the sun did not set there in the summer sol-
stice, sent the following year some mathematicians to
make more certain and exact observations of this curious
phenomenon. They are contained in this book, and
Messrs. Cassini and De la Hire J concluded from them,
that in the latitude of 65° 45' the horizontal refraction must
be 58', or nearly double of that at Paris.

According to an observation made by some Dutchmen§
who passed the winter of 1596-7 in Nova Zembla, in lati-
tude 76° north, the sun, which had entirely disappeared the
14th of November, began to rise again the 24th of January,
viz. six days sooner than was expected according to astro-
nomical calculations ||. If so, when the sun has been two
or three months under the horizon, as the Dutchmen ob-
served in 1597, the cold becomes dreadful, and perhaps
the refraction increases prodigiously. M. le Monnier as-
sures us, that he found by the observations printed in 1599,
that the 24th and 27th of January 1597, there were more
than 4\ degrees of refraction : that he could neither explain
these observations, reject them as doubtful, nor suppose
any error, as was done bv most of the other astronomers,
Kepler, Cassini, Scotto, and, lastly, M. le Gentilf, who
maintained that there were errors in the observations, and
accordingly read a memoir on the subject. If it were not
so difficult a task to winter in these high latitudes, we
might expect such observations as would remove all doubt

* Mem. de l'Acad. 1700, p. 1 12.

f " Refractio solis inoccidui," &c. Holmiae, 4to, 1 695. These observations
in Lapland were made by Messrs. Spole and Bilberg.

\ In two papers of remarks on these observations published by them in
the Mem.de I'Acad. 1700, p. 37.

§ Smith's Optics, p. 61. Remarks. Dr. Jurin's Notes on Varenius's
Geography, vol. i. p. 441. || Leipsic Acts, 1G79.

\ Voy. dans les Mers des Indes, torn. i. p. 395; torn. ii. p. 832.

on

On Refraction, 345

on the subject ; and, perhaps, bring others to light of as
great or greater importance*.

The refraction of the north being so considerable, is very
useful to the inhabitants, who are deprived of the sun's
light during many months ; as it makes the sun rise much
earlier, and set much later to them, than it otherwise would.

About the year 1725, Mr. Flamsteed, the English Astro-
nomer Royal, published his tablet computed from his own
observations : and this was the one commonly used in En-
gland for many years afterwards.

Sir Isaac Newton also constructed one J from theory,
which was first published by Dr. Halley in the Philosophical
Transactions, No. 368, for 1 721 . He made the horizontal re-
fraction 33' 45"; whereas Mr. Flamstecd's was only 33' 0".

But although the refraction might be determined within
a few seconds at all altitudes by observation ; yet, the
law of its increase from the zenith to the horizon was a
subject that occupied the principal mathematicians and
astronomers for more than a centurv§. Newton having
discovered the general principles of attraction, found that
the refraction was a consequence of this law of nature ; and
that it arose from the attraction of the atmosphere on the
particles of light. On this principle the curve which a ray
of light describes might be determined ; since it is succes-
sively attracted by different layers of the atmosphere, in-
creasing in density as they approach the earth, and, conse-
quently, bending the ray more and more from the right line
which it described in the vacuum previous to its reaching
the atmosphere. There are many authors who have en-
deavoured to find from theory the curve described by this
ray in its course, by the assumption of various hypotheses :
but perfection and our attempts to arrive at it, as is well
observed by the elder Cassini in discoursing on this sub-
ject, are like the progress of certain curves and their asym-
ptotes. The principal of these writers on the subject arc,
Bernouilli1, Boscovich2, Bouguer3, Cassini4, Des Cartes5,

* Encyelop. Meth. art. Refraction.

f Hist. Celest. vol. i. p. 396; also Hodgson's Math. vol. i. p. 367. Long'*
Astronomy, p. 254. ± Long's Astr. p. 2.54.

§ In 1714, Cassini published in Mem. de l'Acad. for that year, some me-
thods of finding the refraction by observation, and of determining its quan-
tity by theory. He has also given a table of it for the first .i0° of altitude,
computed, first, according to a rectilinear, and, secondly, according to a cir-
cular hypothesis which he there assumes.

1 Hydrodyn. 1738, p. 221. 3 Oper. torn. ii.

3 Prix de 1729. Memoires, 1739, p. 407 •, 1749, p. 75.

4 Epist. ad Montanari, 1665. Refrassioni eParallosse, &c. 1671. Mem.
for 17 11, and his Astr. vol. i. p. 11. Paris, 1740, in 2 vols.4to.

5 Dioptrique, 4to. Paris, 1637. De

346 , On Refraction.

De la Grange*, Euler7, Gregorv , Hodgson0, Huygensr<%
K^mp11, Lambert12, Laplace1 *, Mayer14, INiewton15, Oriani16,
Thomas Simpson17, Brook Taylor'8, HeinsiusK;, Tobias
Mayer", La Hire*', d'Alembert".

It was conjectured by many of the early writers, that the
refraction was' subject to variations depending upon the
weather: but it then amounted to little more than a con-
jecture, on account of the indifferent manner in which
astronomic instruments were divided. Picard found by
meridian altitudes of the sun in 166*9, that it was greater
in winter than in summer. He found also that it was less
by day than by night. In the observations given at the
end of his journey to Uraniburg*, to settle the latitude of
that place, and its difference of longitude from Paris, for
the purpose of comparing the observations of Tycho Brahe
with those made at the Royal Observatory of Paris, he
found the horizontal refraction for the first limb of the sun
that made its appearance above the horizon there 33' 2",
and for the second 32' 37". So that in the small interval of
time that the sun took to rise, the refraction was diminished
25 seconds by the warmth arising from the sun's presence.

A quadrant being also directed by him from the top of
Mount Valerian towards the summit of the church of Notre
Dame at Paris, he found the depression 20' ; but the sun
had scarcely risen, when it was increased to 22/; exhala^
tions being raised by the sun's presence, and the medium
between Paris and Mount Valerian become more equal ;
whereas, before the sun rose, the air of Paris was more dense
than that of' Mount Valerian f.

The density of the atmosphere being the immediate cause
of the refraction, it was very natural to suppose that it must
decrease as this density became less; whether by causes
which diminished its weight, or by the expansion produced
by heat : and, indeed, astronomers were not long after this,

6 NouveauxMemoiresde Berlin, vol. Hi. ? Mem.de Berlin, 1754, torn. x.

* Astronomy, vol. i. p. 3.58. edit, of 1715, in 8vo.

9 Mathematics, vol. i. p. 867. Fluxions, p. 133.

• IO Traite de la Lumiere, p. 44. Dioptrica, 4to, 1703.
K' >» Analyse des Refract. Astr. et Terres. 4to. Strasburg1, 1799.

10 Les Proprietes Remarquables de la Route de la Lumiere. A la Haye,
1759. Another edition in German, 1773.

'3 Mecanique Cele6te, vol. iv. p. 231. »

M Tables, 1770. »5 Principia, b. i. sect. 14.

,6F,phem. de Milan, 1788. »7 Mathematical Dissertations, 1743.

18 Methodus Incrementorum, 4to. Lond. 1715. Propos. 27, p. 108.

>9 DissertatiodeComputo refractionum Astron. 4io. Leipsig, 1749.

™ De Refractionibus Astronomicis, 4to. Altorf. 1781.

21 Mem. de l'Acad. pour 170L>, p. 52.

52 Opuscules Mathematiques, torn. viii. p. 297.

• Mem. de l'Acad. av.s.ren.. torn. i. f Eucycl. Meth. a,rt. Refraction.

before

On Refraction, 34/

before they discovered that very sensible differences were
occasioned by these circumstances.

But all the honour or' introducing corrections on account
of the variation of density in the atmosphere, as indicated
by the barometer and thermometer, is due to Messrs. Low-
thorpe and Hauksbee ; the former of whom, in 16«8,
proved by a very simple experiment, in the presence of the
Royal Society, that the refractive power of air is directly
proportional to its density* : and the layer, by repeating
and extending the same course of experiments in the year
1708, with the machinery pointed out by the former, found
that the variations of refraction, depending on the barome-
ter, are proportional to the alteration or height of the mer-
cury in the tube : and by a series of these experiments, he
furnished us with a table of the corrections which it is ne-
cessary to make on account of the changes of heat indicated
by the thermometer. These experiments, although not
quite conclusive on the subject, were yet made with as
much accuracy and care as the nature of the machinery,
and the state of experimental philosophy of that time, would
admit. An example is also given, towards the end of his
paper, on the mode of applying them to correct the refrac-
tion. By these, Hauksbee found that a volume of air ex-
pressed by unity, when the thermometer was at 130° above
zero, became, at 50° below, one-eighth more dense : or,
which is the same thing, that the air lost one-eighth of its
density, for an elevation of 180 degrees of Fahrenheit's ther-
mometer; which is exactly the difference of heat between
melting ice and boiling water. But although this one-
eighth, as will be shown hereafter, was too small ; yet it
laid the foundation for other experiments, since made by
several philosophers, by which the quantity of expansion
has been determined more accurately.

We have already hown that the refraction near the pole
is greater than in our climate f ; the degree of cold being
more intense. It was also found to be less in the torrid zone,
where the heat i3 greater than in Europe. Bouguer made a
variety of observations at Peru J, the result of which he has
given us. In 1740, he came down into an island situaied
in the river of Emeralds, called Isle of Inca, where he
determined the refraction from 1° to 7° of altitude: and
the table which he computed therefrom, shows the refrac-

* Haukshce's Exper. 4to, 1709, p. 175.

f It was, however, found by Capt. Phipps, in his voyage to the North, in
17 73, that the refraction in latitude SO0 was the same as in England. But
(his was in summer, J Vide Mem. Ac. 1739, and his Fig. de la Terre.

tion

34 9 On Refraction.

tion to be about one-seventh less than in Europe*. The
horizontal retraction he found to be 27': but at 6' of alti-
tude it is 7' 4" ; and at 45° it is 44". Buuguer then gives
a tablet for Quito, which is more elevated above the level
of the sea. M. le Gen til \ found it greater at Pondieherry
in India, although in the torrid zone.

The refraction diminishes when we are elevated above
the level of the sea. Bouguer observed § the quantity of it
at Chimboraco, 2388 toises above the level of the sea, and
found it in the horizon only 19-3-'. At the cross of Pit-
chinca, 2044 toises above the sea, he found it 20' 4&"; at
Quito, 1479 toises above the sea, 22' 50": but at the level
of the sea 27'. These observations, when joined with the
theory, produced the following rule ; That if we take the
excess of 515S toises above the elevation of the place, with
regard to the level of the sea, the refraction will be as the
square root of this excess. Thus the square root of 5158
toises is 2?', for the horizontal refraction at the level of the
sea, in the torrid zone : and the square root of the excess
of 5158 above the elevation of the place will be its hori-
zontal refraction. The quantity 5158 is the height above
which the refractive matter no longer produces any sensible
effect, at least in the torrid zone||.

But although by this time considerable attention had been
paid to the subject, yet great differences were to be found in
the tables then most in use. Thus at the altitude of 30°,
according to Flamsteed, the refraction was l' 23"; New-
ton V 30"; Cassini V 42"; and de la Hire l' 55^ ; leaving
an uncertainty of more than half a minute: and it must
have been very mortifying to an observer, after having taken
the utmost pains to avoid errors of two or three seconds, to
find his reduced observations liable to so great an error, ac-
cording to the choice of his table of refraction.

It is indeed rather extraordinary, that in a memoir pub-
lished by Cassini de Thury, among those of the Academy
for 1745, he attempted to reconcile a number of observa-
tions with each other, by considering the state of the ther-
mometer only, without at all noticing that of the barome-
ter; although at that time Hauksbee's experiments had
been published about 37 years.

He concludes his paper, as is very natural to suppose,
without being able to make the observations agree : nor
does it clearly appear that the French noticed the above-

* This Table is in the memoir above cited.

t Mem. 1749. Conn. ties Mouv. Celest.p. 1765. J Mem. 1774. Voyage,
torn. i. § Mem. p. 1749. |) Encycl. Method, art. Refr.

mentioned

Thunder-storm at London. 34$

mentioned experiments made by Hauksbee till about the
year 174 9*. It is also worthy of remark, that although the
necessity of introducing corrections on account of the al-
terations of the barometer and thermometer were likewise
shown to be absolutely necessary by Dr. Halley t, and the
circumstance mentioned, and in some degree admitted by
Le Monnier J, yet it does not appear that he followed the
advice of his illustrious contemporary, but merely endea-
voured, as Cassini did, to reconcile his observations with the
state of the thermometer at the time of making these obser-
vations, without taking the barometer into account§.

[To be continued.]

LXI V. Some Particulars respecting the Thunder-storm at
London* and in its Vicinity, on the 3\st of August 1810.
By SirH. C. Englefield, Bart. F.R.S. and F.S.A.

To Mr. Tilloch.

Sir, x\s the stroke of thunder, which was felt in London
at about half after two o'clock in the morning of the 31st
of August last, was, perhaps, the most violent and awful
ever experienced in this country, you may not think the
following account of it from an eye-witness, and who was
very near the spot where it fell and did mischief, unworthy
of insertion in your Journal.

I was with three friends in a coach standing at a house
where we had supped. The house-door was still open, and
there was a strong light from a large lustre in the hall, full
on the coach, and two very bright lamps at the door of the
house. This circumstance was in favour of our seeing the
nature of the light distinctly ; for, had we been in the dark, its
excessive brightness would have so dazzled our eyes as to
prevent all distinct vision. As we got into the coach there
was a small mizzling rain, and a very strong flash of distant
lightning in the N.E., but no thunder that we could hear.
The servants at the door said there had been much distant
lightning for an hour or two.

The sky over head appeared very dark, but the lights pre-
vented accurate observation of it. We were just seated in

* Mem. de I'Acad. 1749, p. 106.— Probably this was on account of some
reflections made by him on the French philosophers who repeated his experi-
ments before the Ro.yal Academy of Paris, and failed in their results. —
Vide his book, p. 196.

f Philosophical Transactions 1720, No. 364.

| Hist. Celeste, 4to. Paris, 1741.

§ See the whole of his Discours prelim, prefixed to tbe work before cited.

the

350 Thunder-storm at London,

the carriage, and my eyes were directed out of the front
window nearly towards the tree which was struck, but
which however I could not see. Two of my companions
were looking out of the window towards the house-door,
from which we were distant five or six feet. We were at
once enveloped by an excessively bright diffused blue light
of more than instantaneous duration, which appeared to
explode into sparks moving in zigzag lines in all directions.
My friends saw them between the carriage and the door,
and their motion was so strong as to make the pillars of
the porch appear to vibrate. The whole had very much
the effect of what in artificial fire-works is called a balloon,
which as it bursts throws out, from its luminous centre,
squibs in all directions. Simultaneous with these zigzag
sparks an astonishingly loud, heavy and single explosion
took place, similar in sound to the discharge of an enormous
cannon directly at us; but incomparably more violent.

The explosion seemed quite on the ground, and was ac-
companied by a sensation of a dull concussion, as if a
vast weight had fallen from a great height on the soft earth
close by us. The sound rose in the air, rolling and echoing
for a very long time much like common thunder.

Astonishment and terror kept us silent for a little while:
we then agreed to quit the coach and take shelter in the
house, the door of which remained open. A few heavy
drops of rain then fell. On re-entering the hall we found
the servants standing aghast at the stroke, which had seemed
to them to threaten to crush the whole building. A very
heavy rain now came on, which lasted for a few minutes.
We were all in fearful expectation of another explosion,
but nothing followed. The rain ceased, and we set out.
As we passed the gate which leads to the palace from Ken-
sington, we stopped, and asked the sentinel what he had seen
and felt. He told us that he could give no distinct account,
for that he was dazzled and nearly stunned by the stroke,
and was scarcely himself for a minute or two, but that it
seemed to him that avast cannon had been fired at him.
In our way to town we saw several severe flashes of light-
ning to the N. W. with very distant thunder, and by the
time we arrived in town the sky was nearly clear, and the
stars very bright.

The succeeding day was bright sunshine, and for the sea-
son extremely hot ; the thermometer being -84 in the shade,'
and free from reflected heat. In the evening there was a
severe thunder-storm and heavy rain, but which did not
cool the air, for both Saturday and Sunday were nearly as

hot

and in its Vicinity. J51

hot as Friday, and the nights uncommonly hot, though very
bright star-light. Having been informed that mischief
was done at Kensington Palace, by the tremendous flash
I had witnessed, I went to view the spot. A large elm in
the outer Palace-yard, near the Guard-house, and about 120
yards from the spot where our carnage stood, was struck in
a manner rather uncommon. A main root about the size
of a man's thigh was blown out of the ground to the length
of twelve feet from the trunk of the tree, and was broken
into three pieces. The trunk or' the iree was barked at in-
tervals, not in a continued line, and this injury quitted the
main stem at the lowest large branch, and followed that
branch up to a fork where some decay appeared in the wood.
Beyond that, no injury appeared, nor was the main stem or
any other branch higher up affected. The whole appearance
of' the tree, as well as the sensation I felt from the explo-
sion, lead me to think that the shock was from the earth
to the passing cloud.

The part of the Palace directly opposite to the tree is a
long building with large arched windows. In these 48
panes of glass were broken by the concussion. This build-
ing is about 50 yards from the tree.

The sentinel at the Duke of Sussex's door was knocked
down by the shock, and remained, as he said, senseless for
some minutes.

Another carriage had just quitted the door where we were,
and which was perhaps still nearer the tree than we were.
The horses stopped short, and remained motionless. The
gentleman in the carriage, when he recovered from his sur-
prise, spoke to his coachman, who as well as the footman de-
clared themselves stunned and blinded. After a pause of a
few minutes they however recovered, and felt no further ill
effects.

I have been several times as near mischief in storms as
I now was ; but I am certain that I never saw or heard any
lightning or thunder which could be at all compared in
tremendous severity to this : indeed it was of a different
kind from any other, as the sound was not sharp and crack-
ling as thunder very near usually is, but deep and heavy.
Two of the gentlemen who were with me have been often
in the southern parts of Europe and the Mediterranean,
where storms are much more severe than is usual in Enc;.
land; but they agreed with me that they never had wit-
nessed any thing at all like this. Its effect in London,
though the nearest part of the town is full two miles from
the explosion, was very singular. Almost every body was

waked

352 Researches on the muriatic Acid

waked by it, and waked with the idea of a cannon fired close
to them.

The watchmen in the streets, and the toll-man at Hyde-
park corner, described the air as completely on fire, and the
tremendous sound as being quite close to them. Jt is not
improbable that the discharge, whether to or from the cloud,
took place in several points at once. If the account in the
papers of a sentinel being struck down, near the Horse-
Guards, was true, this must have been the case, and will
account for the explosion having been so violent in London.
I am, sir,

Your obedient servant,

Tilney-street, Nov. 7, 1810. H. C. EnGLEFIELD.

LXV. Researches on the oxymuriatic Acid, its Nature and
Combinations; and on the Elements of the muriatic Acid.
With some Experiments on Sulphur and Phosphorus,
made in the Laboratory of' the Roi/al Institution*. By
H. Davy, Esq. Sec. R.S. Prof. Chem. R.L F.R.S.E.f

JL he illustrious discoverer of the oxymuriatic acid consi-
dered it as muriatic acid freed from hydrogen %, and the
common muriatic acid as a compound of hydrogen and
oxymuriatic acid; and on this theory he denominated oxy-
muriatic acid dephlogisticated muriatic acid.

M. Berthollet §, a few years after the discovery of Scheele,
made a number of important and curious experiments on
this body ; from which he concluded, that it was composed
of muriatic acid gas and oxygen; and this idea for nearly
20 years has been almost universally adopted.

Dr. Henry, in an elaborate series of experiments, made
with the view of decomposing muriatic acid gas, ascertained
that hydrogen was produced from it by electricity; and he
attributed ihe phenomenon to water contained in the gas ||.

In the Bakerian lecture for 1808, I have given an account
of the action of potassium upon muriatic acid gas, by which
more than one-third of its volume of hydrogen is produced;
and I have stated, that muriatic acid can in no instance be
procured from oxymuriatic acid, or from dry muriates, un-
less water or its elements be present.

Tn the second volume, of the Memoires d'Arcueil, MM.

* Communicated to the Royal Society at the request of the Managers of
the Royal Institution,
f From the Philosophical Transactions for 1809, Part JI.
$ Mem. Acad. Stockholm for 1774, p. 94.
$ Journal de Physique, 1785, p. 325. j| Phil. Trani. for 1800, p. 191.

Gay

in its different States. 353

Gay Lussac and Thenard have detailed an extensive series
of facts upon muriatic acid and oxy muriatic acid. Some
of their experiments are similar to those I have detailed in
the paper just referred to; others are peculiarly their own,
and of a very curious kind : their general conclusion is, that
muriatic acid gas contains about one quarter of its weight
of water ; and that oxvmuriatic acid is not decomposable
by any substances but hydrogen, or such as can form triple
combinations with it.

One of the most singular facts that I have observed on
this subject, and whjeh I have before referred to, is, that
charcoal, even when ignited to whiteness in oxymuriatic or
muriatic acid gases, by the Voltaic battery, effects no change
ID ihcm ; if it has been previously freed from hydrogen and
moisture by intense ignition in vacuo.

This experiment, which I have several times repeated,
led me to doubt of the existence of oxygen in that sub-
stance, which has been supposed to contain it above all
others in a loose and active state; and to make a more ri-
gorous investigation than had been hitherto attempted for
its detection.

If oxymuriatic acid gas be introduced into a vessel ex-
hausted of air, containing tin ; and the tin be gently heated,
and the gas in sufficient quantity, the tin and the gas dis-
appear, and a limpid fluid, precisely the same as Libavius's
liquor, is formed : — it occurred to me, that if this substance
is a combination of muriatic acid and oxide of tin, oxide of
tin ought to be separated from it by means of ammonia. I
admitted ammoniacal gas over mercury to a small quantity
of the liquor of Libavius; it was absorbed with great heat,
and no gas was generated; a solid result was obtained,
which was of a dull white colour; some of it was heated,
to ascertain if it contained oxide of tin ; but the whole vo-
latilized, producing dense punarent fumes.

Another experiment of the same kind, made with great
care, and in which the ammonia was used in great excess,
proved that the liquor of Libavius cannot be decompounded
by ammonia; but that it forms a new combination with
this substance.

I have described, on a former occasion, the nature of
the operation of phosphorus on oxymuriatic acid, and I
have stated that two compounds, one fluid and the other
solid, are formed in the process of combustion, of which
the lirst, on the generally received theory of the nature of
oxymuriatic acid, must be considered as a compound of
muriatic acid and phosphorous acid. It occurred to me, that

Vol. 36. No. 151. AW. 1810. Z if

354 Researches on the muriatic Acid

if the acids of phosphorus really existed in these combina-
tions, it would not be difficult to obtain them, and thus to
gain proofs of the existence of oxygen in oxymuriatic acid.

I made a considerable quantity of the solid compound of
oxymuriatic acid and phosphorus by combustion, and sa-
turated it with ammonia, by heating it in a proper receiver
filled with ammoniacal gas, on which it acted with great
energy, producing much heat; and they formed a white
opake powder. Supposing that this substance was com-
posed of the dry muriates and phosphates of ammonia; as
muriate of ammonia is very volatile, and as ammonia is
driven off from phosphoric acid, by a heat below redness, I
conceived that, by igniting the product obtained, I should
procure phosphoric acid ; I therefore introduced some of
the powder into a tube of green glass, and heated it to red-
ness, out of the contact of air, by a spirit lamp ; but found,
to my great surprise, that it was not at all volatile nor de-
composable at this degree of heat, and that it gave off no
gaseous matter.

The circumstance that a substance composed principally
of oxymuriatic acid, and ammonia, should resist decom-
position or change at so high a temperature, induced me to
pay particular attention to the properties of this new body.

It had no taste nor smell ; it did not seem to be soluble,
nor did it undergo any perceptible change when digested in
boiling water : it did not appear to be acted upon by sul-
phuric, muriatic, or nitric acids, nor by a strong lixivium
of potash. The only processes by which it seemed sus-
ceptible of decomposition were by combustion, or the action
of ignited hydrat of potash. When brought into the flame
of a spirit lamp and made red-hot, it gave feeble indications
of inflammation, and tinged the name of a yellow colour,
and left a fixed acid having the properties of phosphoric
acid. When acted on by red-hot hydrat of potash, it
emitted a smell of ammonia, burnt where it was in contact
with air, and appeared to dissolve in the alkali. The pot-
ash which had been so acted upon gave muriatic acid, by
the addition of sulphuric acid.

I heated some of the powder to whiteness, in a tube of
platina; but it did not appear to alter ; and after ignition
gave ammonia by the action of fused hydrat of potash.

I caused ammonia, made as dry as possible, to act on the
phosphuretted liquor of MM. Gay Lussac and Thenard;
and on the sulphuretted muriatic liquor of Dr. Thomson;
but no decomposition took place; nor was any muriate of
ammonia formed when proper precautions were taken to

- exclude.

in its different States, 355

exclude moisture. The results were new combinations;
that from the phosphuretted liquor was a white solid, from
which a part of the phosphorus was separated by heat ; but
which seemed no further decomposable, even by ignition.
That from the sulphuretted liquor was likewise solid, and
had various shades of colour, from a bright purple to a
golden yellow, according as it was more or less saturated
with ammonia; but as these compounds did not present
the same uniform and interesting properties as that from
the phosphoric sublimate, I did not examine them minutely:
I contented myself by ascertaining that no substance known
to contain oxygen could be procured from oxymuriatic acid,
in this mode of operation.

It has been said, and taken for granted by many chemists,
that when oxymuriatic acid and ammonia act upon each
other, water is formed ; I have several times made the ex-
periment, and I am convinced that this is not the case.
When about 15 or 16 parts of oxymuriatic acid gas are
mixed with from 40 to 45 parts of ammoniacal gas, there
is a condensation of nearly the whole of the acid and alka-
line gases, and from five to six parts of nitrogen are pro*-
duced ; and the result is dry muriate of ammonia.

Mr. Cruikshank has shown that oxymuriatic acid and
hydrogen, when mixed in proportions nearly equal, produce
a matter almost entirely condensible by water; and MM,
Gay Lussac and Thenard have stated that this matter is
common muriatic acid gas, and that no water is deposited
in the operation, I have made a number of experiment*
on the action of oxymuriatic acid gas and hydrogen. When
these bodies were mixed in equal volumes over water, and
introduced into an exhausted vessel and fired by the electric
spark, there was always a deposition of a slight vapour, and
a condensation of from -yV to ^ of the volume ; but the
gas remaining was muriatic acid gas. I have attempted to
make the experiment in a manner still more refined, by
drying the oxymuriatic acid and the hydrogen by intro-
ducing them into vessels containing muriate of lime, and
by suffering them to combine at common temperatures;
but I have never been able to avoid a slight condensation ;
though, in proportion as the gases were free from oxygen
or water, this condensation diminished.

I mixed together sulphuretted hydrogen in a high degree
of purity and oxymuriatic acid gas, both dried, in equal
volumes: in this instance the condensation was not T\r>
sulphur, which seemed to contain a little oxymuriatic acid,
was formed on the sides of the vessel ; no vapour was de-

Z 2 posited $

356 Researches on the rpvrlatlc Acid

posited; and the residual gas contained about 44 of mu-
riatic acid gas, and the remainder was inflammable.

MM. Gay Lussac and Thenard have proved by a copious
collection of instances, that in the usual cases where oxy-
gen is procured from oxvmuriatic acid, water is always pre-
sent, and muriatic acid gas is formed: now, as it is shown
that oxvmuriatic acid gas is converted into muriatic acid
gas by combining with hydrogen, it is scarcely possible -to
avoid, the conclusion, that the oxygen is derived from the
decomposition of water, and, consequently, that the idea
of the existence of water in muriatic, acid gas is hypothe-
tical, depending upon an assumption which has not yet
been proved — the existence of oxygen in oxymuriatic acid
gas.

MM, Gay Lussac and Thenard indeed have stated an ex-
periment, which they consider as proving that muriatic acid
Vas contains one quarter of its weight of combined water.
They passed this gas over litharge, and obtained so much
water; but it is obvious that in this case they formed the
same compound as that produced by the action of oxymu-
riatic acid on lead; and in this process the muriatic acid
must lose its hydrogen, and the lead its, oxygen ; which of
course would form water : these able chemists, indeed,
from the conclusion of their memoir, seem aware that such
an explanation my be given, for they say that the oxymu-
riatic acid may he considered as a simple body.

I have repeated those experiments which led me first to
suspect the existence of combined water in muriatic acid,
with considerable care; I find that, when mercury is made
to act upon one in volume of muriatic acid gas, by Voltaic
electricity, all the acid disappears, calomel is formed, and
about *5 of hydrogen evolved.

With potassium, in experiments made over very dry mer-
cury, the quantity of hydrogen is always from nine to
eleven, the volume of the muriatic acid gas used being 20.

And in some experiments made very carefully by my
brother Mr. John Davy, on the decomposition of muriatic
acid gas, by heated tin and zinc, hydrogen equal to about
half its volume was disengaged, and metallic muriates, the
same as those produced by the combustion of tin and zinc
in oxymuriatic gas,- resulted.

It is evident from this series of observations, that Schecle's
view (though obscured by terms derived from a vague and
unfounded general theory) of the nature of the oxymuriatic
and muriatic acids may be considered as an expression of
i'actsj whilst the view adopted by the French school of

chemistry,

in Us different States. 3j7

chemistry, and which, till it is minutely examined, appears
so beautiful and satisfactory, rests, in the present state of ,
our knowledge, upon hypothetical grounds.

When oxymuriatic acid is acted upon by nearly an equal
volume of hydrogen, a combination takes place between
them, and muriatic acid gas results. When muriatic acid
gas is acted on by mercury, or any other metal, the oxy-
muriatic acid is attracted from the hydrogen, by the stronger
affinity of the metal ; and an oxvmuriate, exactly similar to
that formed by combustion, is produced.

The action of water upon those compounds, which have
been usually considered as muriates, or as dry muriates, but
which are properly combinations of oxymuriatic acid with
inflammable bases, may be easily explained, according to
these views of the subject. When water is added in certain
quantities to Libavius's liquor, a solid crystallized mass is
obtained, from which oxide of tin and muriate of ammonia
can be procured by ammonia. In this case, oxygen may
be conceived to be supplied to the tin, and hydrogen to the
oxymuriatic acid.

The compound formed by burning phosphorus in oxy-
muriatic acid is in a similar relation to water : if that sub-
stance be added to it, it is resolved into two powerful acids ;
oxygen, it may be supposed, is furnished to the phosphorus
to form phosphoric acid, hydrogen to the oxymuriatic acid
to form common muriatic acid gas.

None of the combinations of the oxymuriatic acid with
inflammable bodies can be decomposed by dry acids ; and
this seems to be the test which distinguishes the oxymu-
riatic combinations from the muriates, though they have
"hitherto been confounded together. Muriate of potash for
instance, if M. Berthollet's estimation of its composition
approaches towards accuracy, when ignited, is a com-
pound of oxymuriatic acid with potassium : muriate of am-
monia is a compound of muriatic acid £as and ammonia ;
and when acted on by potassium, is is decompounded : the
oxymuriatic acid may be conceived to combine with the
potassium to form muriate of potash, and the ammonia and
hydrogen are set free.

The vivid combustion of bodies in oxymuriatic acid gas,
at first view, appears a reason why oxygen should be ad-
mitted in it ; out heat and light are merely results of the
intense agency of combination. Sulphur and metals, al-
kaline earths and acids, become ignited during their mutual,
agency; and such an effect might be expected in an opera -

Z 3 lion

35S Researches on the muriatic Acid

tion so rapid, as that of oxymuriatic acid upon metals and
inflammable bodies.

It may be said, that a strong argument in favour of the
hypothesis, that oxymuriatic acid consists of an acid basis
united to oxygen, exists in the general analogy of the com-
pounds of oxymuriatic acid, and metals, to the common
neutral salts : but this analogy, when strictly investigated,
will be found to be very indistinct ; and even allowing it, it
may be applied with as much force to support an opposite
doctrine, namely, that the neutral salts are compounds of
bases with water, and the metals of bases with hydrogen ;
and that, in the case of the action of oxymuriatic acid and
metals, the metal furnishes hydrogen to form muriatic acid,
and a basis to produce the neutral combination.

That the quantity of hydrogen evolved during the decom-
position of muriatic acid gas by metals, is the same that
would be produced during the decomposition of water by the
Same bodies, appears, at first view, an evidence in favour of
the existence of water in muriatic acid gas; but as there is
only one known combination of hydrogen with oxymuriatic
acid, one quantity must always be separated. Hydrogen is
disengaged from its oxymuriatic combination, by a metal,
in the same manner as one metal is disengaged by another
from similar combinations; and of all inflammable bodies
that form compounds^of this kind, except perhaps phos-
phorus and sulphur, hydrogen is that which seems to ad-
here to oxymuriatic acid with the lesat force.

I have caused strong explosions from an electrical jar to
pass through oxymuriatic gas, by means of points of pla-
tina, for several hours in succession; but it seemed not to
undergo the slightest change.

I electrized the oxymuriates of phosphorus and sulphur
for some hours, by the power of the Voltaic apparatus of
1000 double plates : no gas separated, but a minute quan-
tity of hydrogen, which I am inclined to attribute to the
presence of moisture in the apparatus employed ; for I once
obtained hydrogen from Libavius's liquor by a similar ope-
ration : but I have ascertained that this was owing to the
decomposition of water adhering to the mercury ; and in
some late experiments made with 2000 double plates, in
which the discharge was from platina wires, and in which
the mercury used for confining the liquor was carefully
boiled, there was no production of any permanent elastic
matter.

As there are no experimental evidences of the existence

of

in its different States. 35?

rvf oxygen in oxymuriatic acid gas, a natural question arises
concerning the nature of these compounds, in which the
muriatic acid has been supposed to exist, combined with
much more oxygen than oxymuriatic acid, in the state in
which it has been named, by Mr. Chenevix, hyperoxy-
genized muriatic acid.

Can the oxymuriatic acid combine either with oxygen or
hydrogen, and ibrm with each of them an acid compound ;
of which that with hydrogen has the strongest, and that
with oxygen the weakest affinity for bases ? for the able
chemist to whom I have just referred, conceives that hyper-
oxymuriates are decomposed by muriatic acid. Or, is hy-
peroxymuriatic acid the basis of all this class of bodies, the
most simple form of this species of matter?

The phaenomena of the composition and decomposition
of the hyperoxymuriates may be explained on either of
these suppositions; but they are mere suppositions unsup-
ported by experiment.

I have endeavoured to obtain the neutralizing acid, which
has been imagined to be hyperoxygenized^ from hyperoxy-
muriate of potash, by various modes, but uniformly with-
out success. By distilling the salt with dry boracicacid,
though a little oxymuriatic acid is generated, yet oxygen
is the chief gaseous product, and a muriate of potash not
decomposable is produced.

The distillation of the orange-coloured fluid, produced
by dissolving hyperoxymuriate of potash in sulphuric acid,
affords only oxygen in great excess, and oxymuriatic acid.

When solutions of muriates, or muriatic acid are elec-
trized in the Voltaic circuit, oxymuriatic acid is evolved at
the positive surface, and hydrogen at the negative surface.
When a solution of oxymuriatic acid in water is electrized,
oxymuriatic acid and oxygen appear* at the positive sur-
face, and hydrogen at the negative surface; facts which are
certainly unfavourable to the idea of the existence of hy-
peroxvgenized muriatic acid, whether it be imagined a
compound of oxymuriatic acid with oxygen, or the basis
of oxymuriatic acid.

If the facts respecting the hyperoxymuriate of potash,
indeed, be closely reasoned upon, it must be regarded as
nothing more than as a triple compound of oxymuriatic
acid, potassium, and oxygen. We have no right to

* The quantity of oxymuriatic acid in the aqueous solution is so small,
that the principal products must be referred to the decomposition of water.
This happens in other instances; the water only is decomposed in dilute
solution* of nitric and sulphuric acids.

Z 4 assume

360 Researches on the muriatic Acid.

assume the existence of any peculiar acid in it, or of a
considerable portion of combined water; and it is per-
haps more conformable to the analogy of chemistry, to
suppose the large quantity of oxygen combined with the
potassium, which we know has an intense affinity for oxy-
gen, and which, from some experiments, T am inclined to
believe, is capable of combining directly with more oxygen
than exists in potash, than with the oxymuriatic acid, which,
as far as is known, has" no affinity for that substance.

It is generally supposed that a mixture of oxymuriatic
acid and hyperoxymuriatic acid is disengaged when hyper-
oxymuriate of potash is decomposed by common muriatic
acid* ; but I am satisfied from several trials, that the gas
procured in this way, when not mixed with oxygen, unites
to the same quantity of hydrogenf , as common oxymuriatic
acid gas from manganese; and I find, by a careful exami-
nation, that the gas disengaged during the solution of pla-
tina, in a mixture of nitric and muriatic acids, which has
been regarded as hyperoxymuriatic acid, but which 1 stated
some years ago to possess the properties of oxymuriatic acid
gas X, is actually that body, owing its peculiar colour to a
small quantity of nitromuriatic vapour suspended in it, and
from which it is easily freed by washing.

Few substances, perhaps, have less claim to be considered
as acid, than oxymuriatic acid. As yet we have no right
to say that it has been decompounded; and as its tendency
of combination is with pure inflammable matters, it may
possibly belong to the same class of bodies as oxygen.

May it not in fact be a. peculiar acidifying and dissolving
principle, forming compounds with combustible bodies,
analogous to acids containing oxygen or oxides, in their

* If hyperoxymuriate of potash be decomposed by nitric or sulphuric acid,
it affords oxymuriatic acid and oxygen. If it be acted upon by muri at it-
acid, it affords a large quantity of oxymuriatic acid gas only. In this lust
case, the phenomenon seems merely to depend upon the decomposition of
the muriatic ac d gas, by the oxygen, loosely combined in the salt.

f This likewise appears from Mr. Cruikshank's experiments. See Nichol-
son's Journal, vol v. 4to,p. 20G\

\ The platina, I find by several experiments made with great care, has no,
share in producing the evolution of this gas. It is formed during the pro-
duction of aqua regia. The hydrogen of the muriatic acid attracts oxvgcn
from the nitric acid. Oxymuriatic acid gas is set free, and nitrous gas re-
mains in the solution, and gives it a deep red colour. Nilrous acid and mu-
riatic acid produce no oxymuriatic acid gas, Pl.tina, during its solution in
perfectly formed aqua regia, gives only nitrous gas aud nitrous vapour; and
I find, that rather more oxymuriatic acid gas is produced, bv heating toge-
ther equal quantities of nitric acid of I -45, and muriatic acid of 1*18, when
they aie not in contact with platina, than when exposed to that metal. The
oxymuriatic acid gas produced from muriatic acid by nitric acid, I find
combines with about an equal volume of hydrogen by detonation.

p,roperlies

Of the Bogs hi Ireland. 361

properties and powers of combination ; but differing from
them, in being for the most part decomposable by water ?
On this idea muriatic acid may be considered as having hy-
drogen for its basis, and oxymuriatic acid tor its acidifying
principle. And the phosphoric sublimate as having phos-
phorus for its basis, and oxymuriatic acid for its acidify-
ing matter. And Libavius's liquor, and the compounds of
arsenic with oxymuriatic acid^may be regarded as analo-
gous bodies. The combinations of oxymuriatic acid with
lead, silver, mercury, potassium, and sodium, in this
view would be considered as a class of bodies related more
to oxides than acids, in their powers of attraction.

It is needless to take up the time of this learned society
by dwelling upon the imperfection of the modern nomen-
clature of these substances. It is in many cases con-
nected with false ideas of their nature and composition ;
and, in a more advanced state of the inquiry, it will be ne-
cessary for the progress of science, that it should undergo
material alterations.

[To be continued.]

Th

LXVI. Of the Bogs in Ireland.

e first Report of the Commissioners appointed by
Parliament to inquire into the nature and extent of the se-
veral bogs in Ireland, and the practicability of draining and
cultivating them, has just made its appearance. It consists
of seven folio pages, and an Appendix containing, 1. In-
structions of the Commissioners to their Engineers — 3 pages:
2. Names of the Engineers, Surveyors, Clerks, and other Of-
ficers appoiuted and employed by the Commissioners ; with
their Salaries and Rewards — 1 page: 3. Account of all Sums
of Money paid by or under the Authority of the Commis-
sioners^-1 page : 4. Report of Mr. Richard Griffith, jun.
Civil Engineer, on the Practicability of draining and im««.
proving a Part of the Bog of Allen — 41 pages. It is ac-
companied with a Map of Part of the Bog of Allen ; trans-
verse Seetions of Lullymore Bog; a Section of a subter-
raneous River in Lullymore Bog ; and a Section of a Turf
Bank in Timahoe Bog.

The commissioners, after some preliminary observations,
state, that in forming their opinions on the points connect-
ed with their inquiry, they derived their principal assist-
ance from the Great Ordnance Survey of Ireland, executed
by General Vallancey, the Chairman of their Board, h
being the only map which defines either the situation or

boundaries

36$ Of the Bogs in Ireland.

boundaries of the bogs with any tolerable accuracy. They
then report as follows : —

u From inspection of this map we were enabled to con-
sider the greater part of these bogs as forming one connected
whole, and to come to the general conclusion, that a por-
tion of Ireland, of little more than one fourth of its entire
superficial extent, and included between a line drawn from
Wicklow head to Galway, and another drawn from Howth
liead to Sligo, comprises within it about six-sevenths of
the bogs in the island, exclusive of mere mountain bogs,
and bogs of less extent than 500 acres, in its form resem-
bling a broad belt drawn across the centre of Ireland, wiih
its narrowest end nearest to the capital, and gradually ex-
tending in breadth as it approaches to the Western Ocean.
This great division of the island extending from east to west
is traversed by the Shannon from north to south, and is
thus divided into two parts : of these the division to the
westward of the river contains more than double the extent
of the bogs which are to be found in the division to the
eastward ; so that, if we suppose the whole of the bogs of
Ireland (exclusive of mere mountain bog and of bogs un-
der 500 acres) to be divided into twenty parts, we shall find
about seventeen of them comprised within the great division
we have now described, twelve to the westward and five to
the eastward of the Shannon, and of the remaining three
parts, about two are to the south and one to the north of
this division : of the positive amount of their contents we
have as yet no data that can enable us to speak with any
precision; but we are led to believe, from various commu-
nications with our engineers, that the bogs in the eastern
division of the great district above described amount to
about 260,000 English acres, which on the proportion al-
readv mentioned would give rather more than one million
of English acres as the total contents of the bogs of Ire-
land, excluding however from consideration mere moun-
tain bogs, and also all bogs of less extent than 500 acres,
of each of which description the amount is very considera-
ble : of the extent of the latter some idea may be formed
from a fact which we have learned from Mr. Larkin, that
in the single county of Cavan, which he has surveyed, there
are above ninety bogs, no one of which exceeds 500 Irish
acres, but which taken collectively contain above 11,000
Irish, which is equivalent to above 1 7,600 English acres,
besides many smaller bogs varying in size from five to
twenty acres.

* Most

Of the Bogs in Ireland. 362

u Most of the bogs which lie to the eastward of the
Shannon, and which occupy a considerable portion of the
King's county and county of Kildare, are generally known
by the name of the Bog of Allen : it must not however be
supposed that this name is applied to any one great morass;
on the contrary, the bogs to which it is applied are per-
fectly distinct from each other, often separated by high
ridges of dry country and inclining towards different rivers,
as their natural directions for drainage, so intersected by
dry and cultivated land, that it may be affirmed generally
there is no spot of these bogs (to the eastward of the Shan-
non) so much as two Irish miles distant from the upland
and cultivated districts.

" With this first and general view of the subject, we had
no hesitation in selecting at once the whole of the eastern
portion of the great district above referred to, as the object
of our first inquiries, forming in itself one whole, whose
parts had more or less connexion with each other, lying in
the centre of Ireland, in the immediate vicinity of some of
the richest and best cultivated counties : intersected also by
the two great lines of navigation the Grand and the Royal
Canals, arid presenting in common apprehension very con-
siderable obstacles to improvement ; the overcoming of
which would in itself demonstrate the practicability of the
improvement of the bogs of Ireland in most other cases.

" We were further induced to form this selection on the
general principles of beginning at the end of the great divi-
sion above referred to, which lies nearest to the capital, and
proceeding gradually to its termination at the Western
Ocean; not however considering ourselves precluded from
making occasional exceptions, where particular circum-
stances might appear to require it.

"The proportion which the bogs in this district bear to
the entire of the bogs of Ireland, appeared to us a further
inducement ; and we are the more disposed to mention this,
as we find that by some \\e have been thought to have em-
barked in the first instance on too great a scale : on this we
shall merely observe, that having two years allotted to us
for the duration of our commission, we undertook at once
rather less than one third of our task, in the supposition
that it would require about eight months for its execution.

(( Having determined to give in charge the whole of this
district, it became the next object of our consideration, on
what principle we should subdivide it into the smaller di-
stricts, referred to in the first article of our instructions,
for the purpose of being assigned to separate engineers.

Major

36 1 Of the Bogs in Ireland.

Major Taylor's excellent map of the county of Kildare fur-
nisbed us with every necessary information, so far as that
county was in question: but of the King's county there was
no map published; and as it contains not less than 124,000
English acres of bog, it became a most important object
to possess ourselves of the necessary information with re-
spect to them.

" We therefore thought ourselves fortunate in finding
that Mr. Larkin, a surveyor of eminence, had surveyed
the county for the grand jury ; and we contracted with him
to furnish us with*, map of it, on the large scale required
by our instructions 5 and Mr. Larkin making himself re-
sponsible for the accuracy of the survey, we agreed to give
him for it 300/. being at the rate of less than three far-
things per acre for every acre of bog it contained. With
these and the assistance of other documents, we divided
all the bogs, containing above 500 acres, in the counties
of Kildare, King's county, Tipperary, Westmeath, and
Longford, into seven districts : of these we gave the one
which forms the north-eastern part of the Bog of Allen, in
charge to Mr. Richard Griffith ; the south-eastern to Mr.
Brassington ; the north-western to Mr. Townshend ; the ,
south-western to Mr. Longrield ; a district lying princi-
pally in Westmeath to Mr. Jones ; and the bogs in the
county of Longford, and on both banks of the river Inny,
to Mr. Edgeworth.

" We also gave a large district of bog in the county of
Tipperary, which runs nearly parallel to the suir from Ros-
crea to Cashell, in charge to Mr, Aher, wishing to take
advantage of the circumstance of his being able to give a
portion of his time to that district, although not to any
other, on account of his other engagements.

kW We next laid down the principles which were 1o go-
vern our expenditure, in such manner as to secure that the
amount of our disbursements should depend in every in-
stance on the degree of labour to be performed.

" With these views, we fixed the, pay of engineers at
two guineas a day for every day actually employed, and one ,
guinea a day in lieu of allowances lor travelling and. board
and lodging. That of their surveyors at one guinea a day
for each, while employed, to be at once their pay and in
lieu of all allowances of every description. For the starT-
men, chain- men, and labourers, we intrusted the engineers
to make the best bargains in their power, not exceeding
three shillings per day in any instance ; and these terms
we trust will appear extremely moderate when compared

with

Of the Bogs in Ireland, 36*5

with those usual in Great Britain, and considering the
hardships attendant on this peculiar service. The appoint-
ment of the engineers we necessarily hold in our hands,
and select them under the obligation of our oaths ; the
appointment of the surveyors we commit entirely to the
engineers, holding the latter responsible for the qualifica-
tions of the persons they employ.

" We account with every engineer once a week, and he
makes his return to us upon his oath.

" To ccive an idea of the scale and nature of our expen-
diture, we subjoin, as the second and third articles of our
Appendix, copies of accounts already called for by your
honourable house.

" Owing to- the winter season having set in, almost im-
mediately after the appointment of the engineers, and which
was particularly unfavourable to the execution of the sur-
vey, We have as yet received but one of their reports, al-
though thev are most of them, we believe, in a state of con-
siderable forwardness.

" This report we have determined on laying at once be-
fore vour honourable house, considering it as sufficient in
itself, to enable the public to form a pretty accurate opinion
of the degree of information which may be expected from
the execution of our commission ; and feeling also, that if
we deferred it any longer, we should have no other oppor-
tunity before the opening: of the next session : we have ac-
cordinglv subjoined it as the fourth article of the Appendix
to this Report.

" The district reported on contains 36,430 English acres
of bog, and forms the eastern extremity of the Bog of Al-
len. The map furnished to us by Mr. Griffith is on a scale
of four inches to an Irish mile, and is accompanied by
sections of the bog of nearly 200 miles in extent.

" As these maps and sections could not be engraved
without enormous expense, we have subjoined to this re-
port a map executed on a scale as much reduced as is con-
sistent with clearness, and which scale we propose to ap-
ply universally in the different maps which in the execution
of the commission it will become our duty to furnish to
your honourable house; and this map we have accompanied
with three lines of sections of the bog, to serve at once as
specimens of the manner in which the sections are ex-
ecuted, and to convey a clearer view than could be expressed
in words, of the internal structure of a great bog ; a view,
we believe, materially different from any of those generally
received.

" Thcra

366 Of the Bogs in Ireland.

" There are many, we believe, who consider the bogs of
Ireland to be low and marshy tracts of country not very dis-
similar in their composition from the fens of Lincolnshire:
others, aware that the substance of which they are formed
greatly differs from that of the fen districts, attribute ne-
vertheless the origin of both to pretty nearly the same
causes ; while an opinion, more prevalent, and perhaps not
less erroneous than either of the foregoing, attributes their
formation to fallen forests, which are supposed at some
former period to have covered these districts, and to have
been destroyed either by the effects of time, or by hostile
armies in the early wars of Ireland.

" The facts stated in Mr. Griffith's report are obviously
inconsistent with any of these suppositions; the bogs which
he has surveyed being every where in elevated situations,
and the trees which have hitherto been so constantly found
buried in the edges of these bogs, where alone it is probable
they have generally been sought for, are very rarely to be
found in the interior parts at least of this district.

" Without entering in this report into any inquiry as to
the origin of peat bogs, we are however anxious to give to
such persons as have not had an opportunity of examining
them, some idea of the general appearances which they
actually present.

" It appears from Mr. Griffith, that each of the four bogs
included in the subject of his report, is a mass of the pe-
culiar substance called peat, of the average thickness of
25 feet, no where less than twelve, nor found to exceed 42;
this substance varying materially in its appearances and
properties, in proportion to the depth at which it lies :
on the upper surface, covered with moss of various species,
and, to the depth of about ten feet, composed of a mass of
the fibres of similar vegetables in different stages of decom-
position proportioned to their depth from the surface, ge-
nerally however too open in their texture to be applied to
the purposes of fuel : below this generally lies a light black-
ish brown turf, containing the fibres of moss still visible,
though not perfect, and extending to a further depth of
perhaps ten feet under this. In the instance exhibited in
the section at the close of Mr. Griffith's report, are found
small branches and twigs of alder and birch, but we do not
understand him as being of opinion that such is by any
means generally the case : at a greater depth the fibres of
vegetable matter cease to be visible, the colour of the turf
becomes blacker, and the substance much more compact,
its properties as fuel more valuable, and gradually increas-
ing

Of the Bogs in Ireland. 367

ing in the degree of blackness and compactness propor-
tionate to its depth : near the bottom of the bog it forms a
black mass, which when dry has a strong resemblance to
pitch or bituminous coal, and having a conchoidal fracture
10 every direction, with a black shining lustre, and sus-
ceptible of receiving a considerable polish.

" W« have requested Mr. Griffith to make a chemical
analysis of these different strata, which he has done in the
laboraury of the Dublin Society, and an account of which,
with the section above alluded to, forms the Appendix to
his Report. Immediately below this lower stratum, there is
generally found a thin stratum of yellow or blue clay, va-
rying in thickness from one to six feet ; in some places the
peat rests on a thinner stratum of yellowish white marl,
containing on an average about 60 per cent, of calcareous
matter ; this stratum of clay in this district universally rests
on a solid mass of clay and limestone gravel mixed together,
and extending to an unknown depth.

" We should further consider the peat moss as partaking
in its general nature of the property of sponge completely
saturated with water, and giving rise to different streams
and rivers for the discharge of the surplus waters which it
receives from rain or snow : these streams in this district
almost universally have worn their channels through the
substance of the bog down to the clay or limestone gravel
underneath, dividing the bog into distinct masses, and pre-
senting in themselves the most proper situations for the
main drains, and which, with the assistance of art, may be
rendered effectual for that purpose.

" Such is the internal structure of the bogs in this
district.

" Viewing them externally, they present surfaces by no
means level, but with planes of inclination amply sufficient
for their drainage : the highest summit of any part of the
bogs in this district, is 298 feet above the level of the sea,
taken at an ordinary spring-tide in the Bay of Dublin ;
while the lowest point any where on their surface is 84
feet lower than the highest, and therefore 214 feet above
the level of the sea.

" It requires a mere inspection of the map and sections,
to be convinced that there is no part of these bogs from
which the water may not be discharged into rivers in their
immediate vicinity, and with falls adequate to their drain-
age ; and we observe, that in the instance of the liog of
Timahoe, a part of its water is discharged into the sea at
Drogheda, and another part below Waterford/'

The

3T3S Of the Bogs in Ireland.

The commissioners then report their opinion of the prd*
bable expense of these operations, &c. &c. By Mr. Grif-
fith's report to the commissioners, the total amount of es-
timate for draining' the several bogs contained in the eastern
division, or district No. 1, is 147,032/. 6s. \\d. and the
quantity of land to be gained 22,490 Irish (equal .to 36,430
English) acres.

The following description of a section of a turf bank in
Timahoe Bog (see Plate IX.) is copied from the conclusion
of Mr. Griffith's report : —

" The foregoing section is an exact representation of a
turf bank on the southern edge of Timahoe Boo-.

" The surface of the bog has been partially drained for
about 20 perches into the interior, which has occasioned the
upper and most porous part, to subside three feet, the fibresof
moss having lost their watery support, and not being suf-
ficiently strong in themselves to retain their former eleva-
tion. The annual growth of moss on this bog being prevented
by the absence of water, it may be considered as dead.

" In the Report, page 30, T have stated, that in drained
bogs, when the bog- mosses, &c. which compose the upper
surface shall have subsided, and by the near approach of
their mossy fibres (which when alive are kept asunder by
water) and their exposure to the atmosphere shall become
(to a certain degree) putrid, it will be found that various
grasses of good qualjtv, and even white clover, will vege-
tate spontaneously on its surface.

" The bog, of which the section is the face, has now
been superficially drained for three years, and the effect
above described has taken place to a certain degree, as
the common meadow, the tivrin, or jointed grass, and
white clover, are now growing on its surface, though spa-
ringlv ; and the surface of the bog has been so far acted
upon by the atmosphere as to have totally lost the texture
of the moss,' and to have assumed a close-grained earthy
appearance ; whilst in the bed immediately below it, the
mossv fibres are so perfect, as to render the different species
perfectly distinguishable to the botanist, as may be seen by
the specimens which 1 now lay before the commissioners.

" DESCRIPTION AND ANALYSIS.

" No. ] 2 feet thick.

" Surface of bog decomposed by exposure to the atmo-
sphere : mass compact ; contains rarely any vegetable re-
mains ; where they occur thev arechieflv composed of fibres

of

Of the Bogs in Ireland. 369

of moss in the last stage of decomposition, and decayed
branches of heath.

Colour, .. .. reddish- brown :
Specific gravity . . *895.
" 1,440 grains of this substance yielded but 20 grains of
white ashes, which are found to be composed of vegetable
matter.

" No. 2 3 feet thick.

f The mass here is very open-grained and fibrous ; the
moss is usually so perfect, that the different species are ea-
sily discernible to the botanist : the sphagnum- palustre is
observed greatly to predominate.

Colour, . . . . light reddish-brown :
Specific gravity . . '356.
tf 1,440 grains of this substance yielded but 12 of white
ashes, of similar composition to No. 1.

" No. 3 5 feet thick.

Cf Mass open-grained and fibrous ; varieties of moss visi-
ble, but not so perfect as in No. 2: used as turf, but burns
badly, on account of« the openness of its texture, and its
containing no empyreumatic oil.

Colour, . . . . pale yellowish-brown :
Specific gravity .. *408.
<c 1,440 grains of the dried peat yielded but 11 grains of
white ashes, of similar composition to the foregoing.

" No. 4 8£ feet thick.

s< Mass tolerably compact, but still fibrous ; when used
as turf, it burns tolerably well.

Colour, .. .. deep reddish-brown :
Specific gravity .. *87 1 •
" 1,440 grains of the dried peat yielded 13 grains of
yellowish white ashes, composed of vegetable matter, with
a tinge of oxide of iron.

" No. 5. .. . . 3 feet thick*
" Mass compact; fibres of moss rarely discernible*;
numerous twigs, and small branches of birch, alder, and
fir-trees, are observable amongst the peat in this part of
the turf bank. Upon near inspection it was found, that
all the branches and twigs were quite hollow; the wood
being decayed had disappeared, leaving the bark perfect.
This division of the turf bank, when used as turf, burns
pleasantly, but quickly.

Colour, . . . . blackish brown :
Specific gravity .. T030.

•.Branches are not found contained in the body of the Bog generally,
and efen ar the edges not universally.

Vol. 36. No. 151. Nov. 1810. S A. " Analysis.

3 JO Of the Bogs in Ireland.

H Analysis. — 1,440 grains yielded, of volatile em- Grams,

pyreumatic oil 140

Of water, containing a small portion
of oil that could not be separated 834

Light porous charcoal 298

Carbonated hydrogen gas, which
burned with a clear blueish- white
light, equal, if not superior, to the
coal gas 1 68

17440

a 500 grains of this charcoal yielded 15 grains of light
yellowish- white ashes, composed of vegetable matter, and
a slight tinge of oxide of iron.

" No. 6 3 feet thick.

u Mass compact ; contains no vegetable remains 5 when
used as turf burns swiftly, and with a bright flame ; it is
usually denominated greasy turf, from its inflaming quickly
like grease.

Colour, . . . . dull yellowish-brown :
Specific gravity . . #6Q4 Grains.

a 1,440 grains yielded, of volatile empyreumatic oil 180
Water, containing a small portion of oil that could

not be separated .. 816

Light porous charcoal, which, when broken, ex-
hibited a faintly shining lustre 327

Gaseous product, which, when ignited, burned with
a blueish- white light, similar to No. 5 .. .. 117

1,440

ic 500 grains of this charcoal yielded 1 6 grains of yel-
lowish-white ashes, similar in quality to No. 5.

" No. 7 10 feet thick.

"Mass very compact; no vegetable remains visible;
when used as turf burns slowly, and with an unpleasant
smell.

Colour, .. .. blackish-brown.
<c Fracture earthy, with a tendency to conchoidal ; lus-
tre, when first broken, faintly glimmering.

Specific gravity .. .. 1*057. Grain*.

<< 1,440 grains yielded, of volatile empyreumatic oil 138
Of water, containing a minute portion of oil that

could not be separated 538

A very compact charcoal, internal lustre glistening 590

Gaseous product 174

1,440

i.

500

Of the Bogs in Ireland, 371

u 500 grains of this charcoal yielded of deep reddish-
brown ashes 50 grains, which are chiefly composed of
oxide of iron.

" No. 8 4 feet thick.

"Mass very compact ; contains no vegetable remains ;
is seldom used as turf, owing to the unpleasant smell it
gives out when igniied.

Colour, . . . . black.
" Fracture conchoidal in every direction ; lustre shining;
exhibits a strong resemblance to pitch or pitch coal ; and is
susceptible of a high degree of polish.

Specific gravity .. .. 1*236.
(f Analysis. — 1,440 grains yielded, of volatile em- Grains.

pyreumatic oil 124

Water, containing oil that could not

be separated . . 582

Charcoal very compact, internal lustre

strongly glistening . . . . • • 566
Gaseous product, which burned with
a bright light, but unpleasant

smell . . 168

1,440

* 500 grains of this charcoal yielded 96 grains of brick-
red ashes, which are found to be chiefly composed of oxide
of iron.

" No. 9 3 feet thick.

u Marie ; colour, yellowish-white ; does not adhere to
the tongue.

w 100 parts contain : Grams.

Carbonate of lime . . . • 64

Silex 24

Alumine 12

Too

" No. 10 4 feet thick.

" Yellowish-blue clay ; adheres strongly to the tongue,
" 100 parts are found to contain :

Alumine 72

Carbonate of lime . . . . . . 6

Silex, coloured by oxide of iron 22

Too

i( Being very much pressed for time in making the fore-
going analysis, I have been obliged to attend merely to the
most useful results. I hope, however, in a future Report,

2 A 2 to

372 0 n purifying Olive Oil j 6r

to be able to lay before the commissioners a more detailed
analysis, containing a minute examination of the compo-
sition of the ashes contained in the charcoal, and also the
exact composition of the gaseous products."

LXVII. On purifying Olive Oil for the Pivots of Chro-
nometers, By Ez. Walker, Esq.

To Mr. Tilloch.

Sir, After all the experiments which have been made
to decrease friction in time-keepers, nothing has yet been
found to answer this purpose so well as oi!. But it has
long been known that the application of this fluid to ma-
rine chronometers is attended with very pernicious conse-
quences ; for it gradually loses its fluidity during a long voy-
age, and adheres to the parts of the machine, by which all
regularity in its performance is destroyed. Hence I was
led to suppose, that time-keepers might be improved if oil
of a better quality, than that which had been commonly
used, could be procured.

About the year 1799? I made several experiments to se-
parate from olive oil some of those impurities which it is
known to contain, and I succeeded so far as to separate a
thick mucilaginous matter from the best I could procure.
This mucilage is an opake whitish matter, heavier than oil
but lighter than water. The oil from which the mucilage
has been taken is exceedingly transparent in a fluid state,
but after it has been frozen it appears much whiter than
common oil exposed to the same degree of cold.

About ten years ago I sent a small quantity of this oil to
Mr. Barraud, requesting him to make trial of it, and to
March 1802 he gave me the following account: —

" I have," says Mr. Barraud, "just received a chrono-
meter, in which the oil you favoured me with was used ;
which having performed a voyage of 16 months to and from
India, is vibrating as freely as at first, and keeping the rate
it went out with to a fraction of a second. "

Since that time Mr. Barraud has frequently applied to
me for more of this oil, and continues to use it in his best
time-keepers; but to be informed more particularly respect-
ing it, I wrote to him requesting to know the result of his
long experience, and the following extract is taken from his
interesting answer : —

"To

the Pivots of Chronometers, 373

« To Mr. Walker.

" London, 13th October, 1810.

" Dear sir, — Tt is, I believe, upwards of ten years since
you fiist favoured me with some of your purified oil, which
/ have ever since constantly applied to my chronometers;
and on their return from a long voyage I have always
found your oil in good condition, much better indeed than
any which I had before been able to obtain; nor has the
superior quality of yours been confined to my own obser-
vation.

" The late Mr. John Brockbank was complaining to me,
some years ago, of the bad stale in which he found the oil
in his chronometers on their return from India, many of
which had failed in consequence, although the oil he used
was the best he could obtain. I then mentioned the suc-
cess which had attended yours, and at his request furnished
him with a small quantity, which he applied to his chrono-
meters, and afterwards very gratefully acknowledged the
advantage he had derived from its use; having found, on the
return of his chronometers from India, your oil in excellent
condition, and deemed it far superior in quality, for such
purposes, to any he bad before been able to procure.

i( I have presented one of the last phials, which you fa-
voured me with, to Mr. Vulliamy of Pall Mall, who pur-
poses to give it a trial ; but I hope you will be induced, by
what has been already ascertained, to make your discovery
known.

" I am, * * * .

" P. P. Barraud."

Pure oil, such as I have at different times sent to Mr.
Barraudy may be obtained by attending to the following di-
rections.

Put a quantity of the best olive oil into a phial with two
or three times as much water, so that the phial may be
about half full. Shake the phial briskly for a little time,
turn the cork downwards, and let most part of the water
flow out between the side of the cork and the neck of the
phial. Thus the oil must be washed five or six times. —
After the last quantity of water has been drawn off, what
remains is a mixture of water, oil, and mucilage. To se-
parate these from each other, put the phial into hot water .
for three or four minutes, and most part of the water will
fall to the bottom, which mtict be drawn ofl* as before*

The oil must then be poured into a smaller phial, which,
2 A 3 being

374 On Musical Temperaments.

being nearly full, must be well corked, set in a cool place,
and suffered to stand undisturbed for three or four months,
or until all the water shall have subsided, with the mucilage
on the top of it, and the oil, perfectly transparent, swim-
ming upon the'top of the mucilage. When time has thus
completed the operation, the pure oil must be poured off
into very small phials, and kept in a cool place, well corked,
to preserve it from the air.

Lynn, Nov. 13, 1810. E. WALKER.

LXVIII. A further Set of Fifteen Corollaries, to the Musical
Theorems in Page 39, by means of which, the Tempera-
ments of any one of the Concords being given, all the other
Temperaments ana all the Wolves can be calculated with
the greatest facility . By Mr. John Farey.

To Mr. Tilloch.

Sir, X he six musical Theorems which you did me the
favour to print in your 147th Number having given much
satisfaction to several of my musical acquaintances, I am
induced to send you 15 other Corollaries in addition to the
12 inserted at page 44: they are naturally divisible into
three classes, viz.

1st. When the temperament of the ffth is given.

Corollary 13. The temperament of the Hid is = 1 1 2-f-m

— 4 x temperament of the Vth.

_, , lis— 4r u-r-4t . .

By theorem 3, 2 + m is the tern-

s u

4r At

perament of the Hid, and 2 + — m is 4 times

the temperament of V, by theorem 1 : the sum of these
is 1 1 2 -f m, whence the truth of the corollary is
manifest : as indeed it is, by merely abbrevating and
ordering theorem 3.

Corollary 14. 1 12 -f m •— 3 x temperament of V = tem-
perament of VI.

lis u Zr 3t lis— 3r
Here 2 H m 2 m = 2

s u s u s

ii 3/

A m, as in theorem 6 : — and so of all the fol-

u

lowing.

Corollary 15. 11 x temperament of V — 12 2 — m
= Vth wolf.

Corollary

t

On Musical Temperaments, 375

Corollary 16. 8 x temperament of V — 2 = Hid wolf.
Corollary 17. 9 x temperament of V — 2 = Vlth wolf.
2d. When the temperament of the major third is given.

Corollary 18. \ x temperament of 111 — 2-2-2 — £m =

temperament of V.
Corollary 19. -f. x temperament of III + 2f-2 + \m =

temperament of VI.
Corollary 20. 1 8|2 -f 13.n1 — V x temperament of 111 =

Vth wolf.
Corollary 21. 21S +2m- 2X temperament of III =

Hid wolf.

Corollary 22. 23 j 2 +2|m-|x temperament of 111 =
Vlth wolf.

3d. When the temperament of the major sixth is given.

Corollary 23. 3fSfim-j X temperament of VI =
temperament of V.

Corollary 24. £- x temperament of VI — 3| 2 — im =
temperament of III.

Corollary 25. y x temperament of VI r* 28-^-2 *- 2f m =
Vth wolf.

Corollary 26. 28£ 2 -{- 2f m — |- x temperament of VI =
Hid wolf.

Corollary 27. 32 2 -f 3 m — 3 x temperament of VI =
Vlth wolf.

In order to prevent mistakes in the use of Corollary 9,
page 43, it may be proper to remark, that the expression
there given, is for the diesis between *C and bD, *F and
bG, and *G and bA, besides those enumerated; but not be-
tween *E and bF or bC and *C, where the halftones fall,
which have a different value, for which I will give a theorem
on some future occasion.

Also page45, line 5, after "2 only," add,— see the other
equalities of wolves in Scholia 3 and 4.

17 8

In Scholium 6, after — c, — c, and --c, add, in each case,

-—very nearly.

At the end of Scholium 11, page 52, add, — The sharp
andjlat are here, by Cor. 10, each equal to 362 + f -f 3m,
as in Mr. Marsh's Theory of Harmonics, p. 16.

I am, sir,
Your obedient humble servant,
Westminster, Nov. 15, 1810. JOHN FAREY.

2A4 LXiX. On

[ 376 ]

LXIX. On the Barometer, By Richard Walker, Esq,
To Mr. Tilloch.

Sir, An consequence of its having been intimated to me,
that a short rationale, or general view of the various changes
in the weather, and the indications of the barometer, as
connected with them, might not be unacceptable, 1 beg
leave to transmit the following, which maybe considered as
an1 appendage to the paper " On the Application of the Ba-
rometer for indicating the Weather, &c." you did me the
favour to insert in your last Number.

Water exists in the atmosphere in two different stales,
viz. 1st, in a state of chemical combination; that is, so
completely incorporated with the air, as to form with it
one homogeneous transparent fluid; — and, 2dly, in a state
of mechanical combination; which is, when the minute
particles of water are merely suspended in the air, forming
that state of the atmosphere, which is denominated cloudy
or misty.

The dense state of the air being fittest for the chemical
combination above mentioned; clear, dry weather, generally
speaking, accompanies the higher degrees of the mercury
in the barometer, whilst, a rare state of the air being less
capable of receiving the water into chemical combination,
it is then merely suspended in a state of mechanical com-
lination, forming, clouds, mists, &c.

Hence it follows, that, when the mercury stands at or
near fair, clear dry weather is indicated generally ; and
when at or near rain, cloudy or wet weather ; and when
fluctuating mid- way, changeable weather.

It occasionally happens, however, that the atmosphere
is cloudy, and even wet, whilst the barometer is as high as
fair; and clear and dry, whilst the barometer stands as
low as rain. The reason of this, in the first instance, is,
that the air, having become replete or over-loaded with
water, is incapable (by an alteration of temperature, viz.
the air and its contents having become colder) of retaining
or suspending it in a state of chemical combination ; and in
the latter case, which happens after rain, succeeding a con-
tinned dry state of the atmosphere, which having swept
down the vapour with it in its descent ; the air, though then
in a rarer state, is yet sufficient to retain the proportion of
water, now much reduced in quantity, in a state of chemical
combination.

The

On the Barometer. 3 77

The particular or more immediate indication of the wea-
ther which i3 coming, arises from the alteration which is
taking place in the density of the atmosphere, and which
the barometer exhibits by the rising or sinking stale of the
mercury ; the weather becoming comparatively clearer at
the atmosphere is becoming denser, and duller as the atmo-
sphere is becoming rarer*.

Eence, if the barometer were as portable and as con-
venient for reference as a watch, we should seldom be at a
loss to know, at least for short intervals, what kind of wea-
ther was coming f.

The ordinary~range of the barometer in this climate is
from rain to fair; rising however, occasionally, as high
as settled fair; and sometimes, though very rarely, as
high as very dry: and sinking, occasionally? as low as
much rain; and sometimes, though very rarely, as low

as STORMY.

It is scarcely necessary to observe that north and east
winds, in consequence of passing to us from a colder cli-
mate, and over land, bring a denser, colder, and dryer at-
mosphere; and south and west winds, coming to us from
a warmer climate, and over the sea, bring a rarer, warmer,
and damper atmosphere; and moreover, that the capacity
of air for retaining water in a state of chemical combination
is increased by coming from a colder to a warmer tempera-
ture ; and diminished, by coming from a warmer to a colder
temperature.

It must be equally apparent, that the greater or less ele-
vation of the clouds depends upon their own degree of
density, and that of the atmosphere which supports them.

With regard to the immediate causes of the direction
and changes of the wind in this climate, I consider them
as involved in too much obscurity and uncertainty to say
any thing satisfactorily about them ; and with respect to
electricity, which though doubtless a powerful agent in
meteorological effects, 1 consider it rather as a matter of
curious speculation than of practical utility.

I have therefore only to add, that by a due consideration
of the causes enumerated above, connected with the more

* The difference that might be supposed to arise in the height of the
barometer from the effects of different degrees of heat on the atmosphere,
may in observations of this nature be entirely disregarded, g these effects be-
ing very nearly equalized by the expansion and contraction of the mercury
in the barometer, from the same cause.

f As the atmosphere is almost constantly varying in its degree of den-
sity ; so is the barometer, which is an accurate measure of its density, as con-
ttantly varying in its altitude, and should therefore be frequently referred to.

obvious

378 Reflections on some Mineralogical Systems.

obvious effects of the sun's varying influence in raising
and dispelling vapours, we may, I think, account pretty
satisfactorily for the various vicissitudes of weather, which
mark the different seasons throughout the year; and, by the
relation of the barometer to those causes, be enabled to
foresee, with a considerably greater degree of certainty than
is commonly supposed, the different'ehanges of weather
which are, at all times, about to take place.
I am, sir,

Your obedient servant,

Queen-street, Oxford, RD. WALKER.

Nov. 17th, 1810.

LXX. Reflections on some Miner alooical Systems. By
E. Chenevix, Esq. F.R.S. and M.R.LA.,'&c. Trans-
lated entire from the French, with Notes by the Trans*
lator.

{ [Continued from p. 303.]

SUPPOSED DEFECTS OF THE CRYSTALLOGRAPHJCAL
SYSTEM.

1V1. Hauy has been reproached for his principle of speci-
fication and his definition of the species : one alleging that,
according to him, muriated soda and sulphated lead are of
the same species ; another, that the two indications of the
species are often in contradiction, and that the same form
of molecule does not always accompany the same chemical
composition, and vice versa. Some do not like the octaedron
for a primitive form, because, to preserve unity of form in
the integral molecule, it is necessary to suppose empty spaces ;
others, in short, reproach him with the difficulty of finding
all the directions of the cleavage (or the construction of the
cleft), and the system also with a want of generalization;
and finally, as a dernier resource, that we must return to
the system of external characters.

Will it be believed that I have heard the first of these ob-
jections made by a celebrated philosopher, a professor who
draws around him from all parts of the world the zealous
lovers of mineralogy, and who repeats it at least once a
year in his public lectures ? that I have seen it printed and
published in a work which passes for one of the best on the
systems of this professor ? It is of German origin, and
proceeds, no doubt, from the circumstance that they have
not yet learned to count even to two on their lingers ; a
great misfortune for a philosopher. Identity of form in the
integral molecule, — this is one condition in order that two

minerals

Reflections on some Miner alogkal Systems. 379

minerals should be of the same species ; and hitherto mu-
riated soda and sulphated lead are in this state. Identity of
chemical composition, — here are two conditions, if I have
rightly calculated ; and muriated soda and sulphated lead
are not of the same species.

M. Haiiy himself has answered the second objection in
a manner which leaves nothing to be added. It is true, that
with the same form of integral molecule we have a different
chemical composition j but let us observe under what cir-
cumstances.

There are three geometrical figures which perform the
office of integral molecule : Admirable simplicity of nature,
that with such slender means can compose forms in an in-
finite number I These figures consist of those with four
sides, the least number possible to contain a solid ; those
with five, and those with six ; all are the most simple. But
they are all susceptible of an infinite variety in the dimen-
sions of their sides and in the inclination of the faces which
terminate them, although all have a fixed term of regu-
larity towards which they tend. It is but in these terms,
which in this respect are the limits, that we find the iden-
tity of the physical with a diversity in the chemical mole-
cule. The repetition of regular forms which are the li-
mits of others, such as the cube and regular tetraedron in
the different species, appears to me to prove nothing against
the system of M. Haiiy ; on the contrary, it gives us cause
to admire the mechanism of nature, which delights in mul-
tiplying its severe and rigorous features amidst the variety
in which it indulges. The most regular forms are also the
most simple ; and I take it for an axiom, that it is but in
approaching simplicity that we approach nature.

Let us examine if the reverse of this be equally true ; that
is to say, if with the same chemical composition we find a
difference in the physical molecule. There is only one case
well ascertained ; it is that of carbonated lime and arraoo-
nite. Chemists the most celebrated in the art of analysis,
Messrs. Vauquelin, Thenard, and Klaproth, have found no
difference between these two minerals ; and I acknowledge
that I have repeated the analysis of six different specimens
of arragonite, comparatively with the carbonated lime, and
I am convinced of their identity of composition. M. I Jaiiy
found a difference in the form of their integral molecules.
How admirable is this science, to which, — in the first years
of its existence, and before that time has impressed it with
those marks of rigour which continued observations inva-
riably effect, — only one objection can be made against it

that

380 Reflections on some Miner alogical Systems.

that appears to have any foundation ! How many do \\t
not find against those sciences which have been refined by
the lapse of ages^ and which have resisted the persecutions
of inquisitors armed with all the severity of bad inten-
tion ? If the cavils of certain persons had been listened
to against the axioms and definitions in mathematics, we
should now, indeed, have been destitute of this route.
Others would have deprived us of physics and chemistry, at
the same time with the very matter which served them as an
object, and, scarcely will it be believed, our'own existence.
If we make a thousand steps in advance, and one remains
which we are unable to pass, should we for this abandon
that which we have already attained ? The philosopher
ought at least to wait, and watch with a calm eye and un-
shaken patience the moment when nature shall betray itself,
if our efforts can effect nothing on it. The state of science
is a state of expectation.

Even when ve have a rigorous demonstration that che-
mistry and mineralogy do not correspond in this solitary
case, what then shall we say ? In every thing which nature
presents to our contemplation, it leads us, by views taken
in all directions, to the point where we find ourselves ar-
rested. In the mass of our learning, what system compre-
hends it entirely ? yet, notwithstanding their imperfections,
systems still serve us. No one thing appears better deter-
mined than the species in zoology, as it consists in a cate-
gorical answer to a very simple question. There are, how-
ever, animals respecting which it is still disputed whether
they should be admitted as species or varieties. The vege-
table kingdom has also its causes of uncertainty. Never-
theless, these two kingdoms offer a greater number of cha-
racters, as the beings which they embrace are endowed
with more marked and more elevated qualities than those
which belong to the mineral kingdom. Why then should
more rigour be required of the latter, with less means ?
Why is it wished to deprive us, on a single deposition
against it, of a system which is supported on mathematics
and confirmed by chemistry ?

Ferriferous carbonated lime * is a mineral often cited by

those

* Brown spar of Jameson, sidero calcite of Kirwan, chant cqrlonotfe
bfttirisfante oi Brogtiiart, who makes it the ninth subspecies of carbonated
lime (or calcareous spar), and separates it from what he calls for spithicjiie,
or sparr; iron, which he arranges among the metals, on account of its su-
perior ' .ty, and its power of occasionally attracting the magnet.
The property oi b( own when exposed to nitric acid or the fire,
„;cs the above name ; but this is cemmoo to both kinds.

This

'Reflections on some Mineralogical Systems. 381

those who profess another mineralogical belief than that of
M. Haiiy. It is ranked in the same species as simple car-
bonated lime, although it often contains but one-third car-
bonate of lime, and The remainder iron or manganese : evi-
dent marks also indicate an additional structure of the cleav-
age in the direction of the great diagonal, which leads to
solids of two or more forms.

We have observed that there exist vacuums between the.
molecules of bodies, in which foreign matter may lodge.
It may therefore happen that particles of iron or oxicied
manganese are deposited in the vacuums of carbonated
lime : when this is the case, we have the mineral in ques-
tion. But it does not thence follow that the integral mo-
lecule should change its form, as the oxided iron does not
enter it, and as it, in fact, undergoes no change in its che-
mical composition. One of the indispensable properties of
the molecule of minerals being not to vary but by two
indications at once, then whatever enters not the integral
molecule, although it forms a part of the mineral, should
not change it : this law is constant, whether it relates to the
quantity of extraneous substances, or to their nature, their
form, or their tendency to crystallization. But as foreign
matter can interpose itself between the molecules with
which it is surrounded or enveloped, it may influence their
relative dispositions; whence will result secondary forms,
which shall differ according as the spaces between the mo-
lecules are empty, or more or less tilled. The passage of
light may also be obstructed by the interposition of opaque
matter, and the colour must participate in that of the
interposing substances. The molecules being enveloped
may be further removed from immediate contact, and thus
offer a greater facility of separation : the junctures also may

This supposed improvement, tberefoie, of HauVs arrangement, by subdi-
viding and transposing ihe varieties of tiiis subspecies, exists more in
names than characters; Tor even those of specific gravity and pf astracting
the magnet depend solely on the preponderance of iron over rhe manganese ;
and sometimes the i;iuntity of manganese is ve*-y considerably greater than
that of the inn, without any difference in exterior character. To change,
torture, or reject a system for such a tnping and merely apparent anomaly,
would betray m<jr«J ignorance of the diversity of rfafure than scientific ex-
piariencej t«> attempt to modulate an otherwise complete system to -
things, would be to pay more attention to exceptions than to rules, and
evince nothing but tpe foppery o!' minuteness, which never can exist in
minds expanded by true science. Mr. Chenevix's chemical explanation,
indeed, of this phenomenon is pei fectly sufficient, and more satisfactory
than M. B scheme of minute division, which may be sometimes

very right aud sometimes very wrong. His epithet brunissonte, or brown-
ing, adopted from the Germans, is equally as applicable to his sparry iron
as to this carbonated lime ; that of Haiiy, although long, is correct and in-
teiligible, — ferro-manganesiferous carbonated lime. — Trans.

be

382 Reflections on seme Mineralogical Systems

be more distinct, and the-specific gravity greatly augmented,
as the spaces otherwise empty or occupied with air shall be
filled with heavier matter. The action of chemical men-
strua may likewise be modified ; and if a molecule of a sub-
stance easily soluble is surrounded with molecules of
another which resists chemical solvents much longer, the
former may be in some measure protected from their power.
Other effects may take place ; but, we repeat it, the inte-
gral molecule remains the same. Now, in the ferriferous
carbonated lime we do not find the same Variety of forms
as in the simple carbonate ; the former is opaque, the latter
is transparent ; the one has lines which seem to mark a
direction of the cleavage more than in the other; the
specific gravity of the first is 3*784, that of the second is
2-718 ; and the ferriferous carbonate is more easily dissolved
in acids. These are all the phenomena which result from
the interposition of extraneous substances in the empty
spaces between the molecules of one of the bodies exhibited
in this example.

EXAMINATION OF THE IDENTITY/ AND UNIFORMITY OF
THE INTEGRAL MOLECULE. OBJECTIONS ANSWERED.

But I shall be told that the molecule differs, since there
is a direction of the cleavage more in the one than in the
other. It is the foreign substances which render the junc-
tures more sensible in one case than in another ; and it 19
possible that the same junctures exist in the simple as well
as in the ferriferous carbonate, without our having as yet
commonly observed them. I can almost venture to assert
that thev do exist. I have a specimen of carbonated lime
very white and very well crystallized in an obtuse rhomboid
of a primitive form, and of the same specific gravity as the
simple ordinary carbonate, but of a milky transparence,
and in which the lines are as distinct as in any specimen
whatever of ferriferous carbonated lime. This specimen,
nevertheless, presents in analysis no trace of any substance
foreign to the purest Iceland spar. It is therefore very pro-
bable that simple as well as ferriferous carbonate may be
divided in the direction of the great diagonal : hence it is
expected to overturn the system of M. Haiiy. But in all
that we know, and all that we seek to know, it is uniformly
our own horizon which we substitute for the limits of na-
ture. M. Haiiy has found in carbonated lime three direc-
tions of the cleavage parallel to the faces of an obtuse
rhomboid, and no more. He stopped there, and has not
wandered in the regions of imagination. Although his

work

Reflections on some Miner alogkal Systems. 383

work was finished, that of nature was not; and it may still
present some specimen which shall reveal its secret. If
we find that carbonated lime may be divided more than
once, it thence results only that we have taken for an inte-
gral molecule: that which we have been able to observe, but
not that which really exists; precisely as chemistry declared
that the emerald was composed of silica, alumine, iron and
lime, until it was discovered that what was considered only
as alumine contained also glucine, and that the iron was
combined with chromium. But for this chemistry did
not lose its importance. The integral molecule likewise
may be found different from what has been believed, if what
T have here observed should prove true; yet the general
.system of the molecule is unshaken.

A recent analysis, however, appears to have excited much
interest in this point. Some of this pretended ferriferous
carbonated lime has been found, in which there exists
scarcely a trace of lime*. I readily believe it, but shall
not for that renounce the method. In M. Haiiy's col-
lection^ there is a mineral which at one end is ferriferous
carbonated lime, excessively yellow, containing iron,
striated and dividing in rhombs. In extending from this
end the colour fades, and the other characters which distin-
guish the common from the ferriferous carbonated lime
become weaker till they finally disappear. Whoever ex-

* The Wernerians, however, cannot consistently avail themselves of this
defect, as the mineral still retains the same external characters ; it is the
chemists only who are entitled or qualified to decide on it, and they wili not
be very precipitate in pronouncing a sentence, since Mr. Davy has proved
that even one per cent, of oxygen can produce effects on the external
character of substances, which would serve the Wernerians not merely for a
specific but even a generic difference. Should they object to the introduction
of lime in the name of this mineral, they must recollect their own holzstem,
woodstone, or petrified wood, which they have thus denominated, and
made a particular species in flint genus, although they will not pretend that
it contains any vegetable or woody matter ; only that, like the .mineral
under consideration, it owes its form to that substance. Mr. Jameson,
indeed, makes an apology for considering a petrification (not petrefaction, as
he erroneously writes it, and which the learned Dr. Kidd applies to incrus-
tations), " a particular fossil species," by alleging " that woodstone
differing in its external characters from all other fossils, the justness of the
Wernerian method is evident." Upon this principle he should have divided
his species, as the colours, and even specific gravity of petrified oak, ash, &c.
are very different. He adds, that " it re. reives a good polish, and serves for
the same purposes as agate. '* I have examined many specimens of petrified
wood in various countries, but have never been so fortunate as to find any
that could be substituted for agate, or was susceptible of a polish even equal
to coarse marble. Surely the professor cannot have noticed such characters
merely to make Werner's fine chemical theory of the solution and infiltra-
tion of agate less fanciful, or give an example of transition from Wood to
■ petrifaction agate, which is wood penetrated with se>:eral of the fossils
that constitute agate ? "—Trans.

amines

384 Reflections on some Mineralogical Systems,

amines this specimen attentively and unprejudicedly, must
believe that the whole has been common carbonated lime,
which has been exposed to the action of a sulphuric or
other solution of iron, that the carbonate of lime has been
gradually dissolved, and yielded its place to the oxide of
iron, precipitated from its solvent by the double affinity of
the lime for the acid in the solution of iron, and the oxide
of this metal for the carbonic acid. The carbonated lime
has served as a matrix to the oxide of iron, and it is very
possible that the direction of the laminae in the way of
the great diagonals may be rendered more sensible by the
solution of the old and precipitation of the new molecules
which came to deposit themselves in this abode. If, how-
ever, I have admitted the existence of a ferriferous carbo-
nated lime, where there is no lime, it is because I have seen
petrified wood where there was no wood.

But, in taking the first explmation.generally, it seems
that, far from making the case of which I have spoken the
subject of an objection, it is for chemistry to draw from it
the greatest possible advantage. A grand effort which yet
remains to be made, is to distinguish between mixtures and
combinations. Let us suppose a mass, A, composed of
any number of physical elements, which have for chemical
molecules the substances a ! b + c, and another mass, B,
the chemical elements of which may be m + n. It is de-
manded if a mixture or a combination shall take place in
putting the bodies A and B together? If by physical divi-
sion we find a molecule similar to the molecule A, another
similar to that of B, and that by ehemical division we found
the chemical elements (a + b + c \ m + n,) it is evident that
we have a mixture, Cut it we find a new molecule, C,
with the same chemical result (a -\- b + c + m A- n), we
have a combination. It is therefore for chemistry, en-
lightened by physical (or mechanical) division, to resolve
this great problem ; and it is to restrain its influence too
much to confine within the province of mineralogy, that
which may guide our researches over the whole of nature
or the material world.

Let us lake one particular case, — the neutral tartrate of
potash. This salt, like all others, has a physical and che-
mical constitution peculiar to itself, i\', in, adding to it
tartaric acid in a quantity sufficient to convert it into acid
tartrate ol potash, and in submitting these two substances
to all the chemical means of combining them, we find the
same form of physical molecule in the one part, and the
form of the physical molecule of tartaric acid in the other;

we

Reflections on some Mlneralogical Systems, 385

we can safely say that no combination has taken place between
these two substances, whatever may be the difficulty ex-
perienced in separating them. If, on the contrary, these
two molecules lose the form peculiar to them, as tartrate of
potash and tartaric acid, to effect another conjointly, we
should conclude that thev have combined to form but one.
By afterwards adding some soda as a neutralizer, we may
learn the true state of these principles, with respect to each
other, in consulting crystallotomy to know if molecules
of tartrate of potash and also those of tartrate of soda
are found, or molecules of another form, which will be
that of a tartrate with a double base.

The great quantity of foreign matter which has been
found interposed between the physical molecules, without
effecting any change in their form, has shaken the faith
of many persons. The gres (sandstone) of Fontain-
bleau (quartziferous carbonated lime, Haiiy), in which the
law is the same as in the pure calcareous spar which
sometimes accompanies it, is an example. But the
degree of tendency to a regular form may be much greater
in one mineral than in another, and surmount all the
obstacles which the mixture of heterogeneous species
could oppose to it. This is what we see in our labo-
ratories; it is what the gres of Fontainbleau shows us
in that of nature. The power of becoming symmetrical
may vary in crystallizable substances, like the capacity of
saturation in salifiable bases.

As to the octaedron considered as a primitive form, it
has been observed that sections by planes parallel to its
faces, divide it again into eight tetraedrons and six oc-
tacdrons, and this in succession to the ultimate point ;
so that, to maintain the unity of the integral molecule,
we must suppress in the mind one of these two figures.
In order to adhere to the most simple, as that which
appears to have the most just title to a place in nature, the
preference has been given to the tetraedron, in supposing
that between the molecules there are empty octaedral spaces.
Geometry has found that this hypothesis embraces one
third of the quantity of matter in a mineral which has
this primitive figure, and that the two other thirds are
empty. But this takes place precisely in the species of the
calcareous genus which has the greatest specific gravity,
while nothing is said of the vacuums in the other species.
Here, it is said, there is a contradiction.

If we were still ignorant of all that we have learned
respecting the density of bodies, this objection would be

Vol. 36. No. 151. Nov. 1810. 2 B some-

386 Reflections on some Mineralogical Systems.

somewhat specious. In the present age natural philoso-
phers cannot admit it.

Specific gravity may he viewed in two points : — where
the molecules of all the bodies have the same density, and
then the variation of specific gravity between one mass and
another depends on their particular arrangement with re-
spect to each other, which admits of more or less empty
spaces in the different bodies in nature; or where the mole-
cules themselves have a different density in each substance,
the relative disposition being the same in all. It is evi-
dent that, on the first supposition, the molecule and the
body which it contributed to form would have properties
different in this respect, and that we could never learn
any thing of the true specific gravity of the molecule,
however correctly we knew that of the body. Platina,
for example, which I estimate at nearly 21*437, might
have a molecule ten times (100 times if it is wished) more
dense than it; and the lightness of the aggregate would
result from the space, in which 214370~ molecules of
platina might lodge, if the arrangement was the most fa-
vourable possible for' this effect, containing only 21437.
The specific gravity of cork has been estimated at 0*24.
A space therefore which contains 21437 molecules of pla-
tina could contain but 240 of cork, in this hypothesis ;
yet a molecule of platina loses in water the same quantity
of its weight as a molecule of cork.

In the second supposition we discover the weight of
the molecule having that of the mass ; and the number of
molecules in a given volume of platina would be equal to
that which the same volume of cork would contain.

There exists, indeed, a third hypothesis, composed of
these two, and which supposes at the same time a variation
in the density of the molecules and in their arrange-
ment. I shall not discuss what hypothesis should be pre-
ferred in sound philosophy. 1 speak at present like those
mineralogists who judge all by their senses, and I admit
every thing which they wish, in order to refute all.

In the hypothesis where the density of the molecules is
supposed variable, it is evident that the objection falls of
itself; for I am able to give those molecules whatever
density I choose, within reasonable limits. Now when
in fiuated lime there would be the two thirds vacant which
form the subject of reproach, the density of the mole-
cule would be but three times greater than that of the
mass. Yet the density of a molecule of gold would be
six times greater than in this supposition. Thus, by ad-
mitting

Reflections on some Miner a logical Systems, 387

nutting in the molecule of filiated lime the necessary den-
sity to obviate this objection, we do not commit any indis-
cretion.

Now let us take the contrary hypothesis, and say that
the molecules of all bodies have the same density, so that
the variation of specific gravity in them all depends solely
on the vacuums which exist between them. If in any
body whatever the quantity of vacuum be zero, we have
an absolute plenum ; and the heaviest body which we
know should be that which would present us with this
state of things. Platina furnishes us with an example,
while this collection of hypotheses contains the fact most
favourable to the objection.

Chabaneau has found the specific gravity of platina to
be 2*400, others 2*300, some 2*200, and 1 have observed
it beyond 2*1 ; that of filiated lime is 3*191. Let us
simplify the expression of these relative weights, and we
shall have, in an equal volume, the quantity of matter in
platina, in fluated lime, and in water : : 1 : 4- : TlT. There is
then -f- of vacuum in fluated lime, or ££-, while the hypo-
thesis of M. Hauy notices only ±±. There remain, then,
■iff more than are wanting to combat the objection. There
are also necessarily vacuums in other calcareous species. In
taking platina, as above, for an example of an absolute
plenum, we shall have, according to the data which the
specific gravity of this body furnishes, ~-f£ of vacuum in
carbonated lime ; -£f4 in phosphated as well as in filiated,
and £f£ in sulphated lime. The hypothesis of M. Hauy,
instead of being incompatible with what observation
teaches respecting the density of fluated lime, is not suffi-
cient to account for its lightness; and the -ffo of which it
takes no notice, as well as the vacuums in other species
which are passed over in silence, are so many particular
cases of a verity demonstrated in physics : its great noto-
riety doubtless made M. Haiiy believe that it was unneces-
sary to anticipate this objection by answering it at first.
Instead, therefore, of accusing him of having carried off'
too much matter from fluated lime as a mineralogist, we
should rather consult him as an examiner of nature {physi-
cien)9 on the fate of nearly -±-£ of which he is silent. It is
difficult to conceive how any one could permit himself to
make such objections, especially when we consider ike
source whence \hey sprung,

rl lie divisibility or carbonated lime before mentioned, by
supersections which yield molecules of two different
iorms, and also what we have just observed respeeting the

2 B 2 oetaedron

388 Reflections on some Miner alogicul Systems,

octaedron as a primitive figure, give occasion for some
reflections which I shall here venture, although I feel by
their importance, and by the considerations necessary to
give I hem due illustration and support, that these points
merit being treated separately and at greater length. It is
possible that there bad been but one single form of mole-
cule in all nature, and that this form was a tetraedron.
In the octaedron the existence of this figure is inevitable,
since it results from sections parallel even to the faces of
the octaedron. It also occurs, and simultaneously with
other figures, from supersections made in the direction of
the diagonals of all the faces of a parallelopiped. The
triangular prism likewise affords it, but of different forms,
by supersections in the direction of the diagonals of the
lateral faces. As we must necessarily allow of vacuums
between the molecules of bodies, we may suppose that the
interstices are those portions of spaces, from which every
other figure (except * the tetraedral molecule of the body,)
would have disappeared. The form and the quantity of
these interstices, conjointly with the presence of a greater
number of the proper molecules of the body, will pro-
duce all the diversities of specific gravity which are known
in nature ; and when we consider that a portion of space
cannot be inclosed by less than four planes, we observe in
the tetraedron that mark of simplicity which nature im-
presses on all her works.

*f All the molecules in nature are spherical," said a most
celebrated German, in showing me that with small balls of
ivory he produced all the figures which he wished. " The
English and the French have not yet advanced so far," he
added. " From reason," said I to myself. The proba-
bility that nature would have given the preference to such a
solid rather than to another for an universal molecule, every
thing otherwise being equal, would be inversely as the
number of planes which terminate them. Between the
sphere and the tetraedron it would be as four to infinity.

Besides its being hitherto impossible to extend the system
of the integral -molecule to all minerals, there are naturalists
who reproach it with the difficulty of finding the directions
of the cleavage in many cases, the trouble of calculating
them, 8cc. We should no longer use the microscope, the

* This exception enclosed in ( ) appears superfluous ; the author is
speaking of the presumed vacant spaces or vacuums between the molecules ;
but neither the figure nor the forms of these vacuums interest the practical
erystallographer, as tangible solids are quite sufficient to establish the va-
lidiiy of the general principle.— Trans.

telescope,

Reflections on some Mineralogical Systems'. 389

telescope, nor the chronometer, for they also are very dif-
ficult to execute. Let us content ourselves with dress-
ing, sleeping, and eating, convinced that without the pen-
dulum and the telescope the stars will continue their
course, and bring back the hours of sleep and the restora-
tion of our powers.

The last objection to which I shall pay any attention is
that which says, briefly, " We must abandon the system of
M. Haiiy for that of the external characters, as the inte-
gral molecule cannot be observed in all minerals. " One of
the great advantages of the system of M. Haiiy, one of
its principal beauties, is to follow nature, and to speak as she
does. Where she has finished her work in the highest
manner of which it is susceptible, M. Haiiy does the
same; and if she produces a mineral endowed with all the
characters which, according to us, compose the most per-
fect state, it is classed and defined as such. If she has
been sometimes less rigorous in impressing her mark of
perfection, the system follows the same course; while the
method of external characters renders equally the honours
of rigorous classification to sapphire and to the alumina of
Halle. To say that we should make no use of an excellent
system because cases occur where it is unavailable, is to say
to a patient, Lie not on a feather bed ; for, if you are de-
prived of it, you will be reduced to the necessity of sleep-
ing on a board. It is to tell a man in health not to take
nourishment, for if the provisions become deficient he
could no longer eat.

WERNERIAN TRANSITION OR PASSAGE.

Before terminating these considerations on the species,
there is a mineralogical being of which it is necessary
to say a few words. It is a being which is neither of this
nor that species, but belongs to all. It is not sapphire, for
instance, but it resembles it; it is not ruby, but it would
be perhaps if it were not something else. It is so consti-
tuted that, with a real and material existence, it lives by
borrowing, as to its modifications, and puts on the cha-
racters of others. It is a hermaphrodite mineral; an infant
with two fathers that both disown it ; that the other king-
doms of nature reject as a monster; but that mild and
easy mineralogy has received into its bosom, and called it
passage.

There are two manners of conceiving the existence of
this interesting refuse of the organized kingdoms.

Let us first suppose a mineral less hard, less brilliant, less
2 B 3 blue

390 Reflections on some Mineralogical Systems,

hlue and lighter than sapphire ; but harder, more brilliant,
bluer and heavier than alumina of Halle. Ii will represent
to us what should be understood by a passage from alu-
mina of Halle to sapphire. It is in this manner that
they have given a very great number of passages ; too
great, indeed, to cite them. Let us take some analogous
cases in another kingdom.

A great naturalist has told us that the paw of a bat brings
it near to man; and that every one may see the organ of
flight, which merits it a place among birds. Here then is
a passage from a bird to man. But what is meant by
that? Is it understood that nature, having succeeded in
making a bird, conceived the project of forming a more
perfect being, but that her first essay produced nothing
better than the image of a hand and a horrible grimace ? Or,
is it pretended that, if in the metempsychosis/ the lord of
the earth should become a bird, he must pass under the
form of this hideous animal ?

Of all that we can consider as passage, there is nothing;
so marked as an animal engendered between two indivi-
duals of different species. Such is the mule ; every mem-
ber of which participates in the qua! 1 lies of one or other
of its parents. In the capital of the beautiful kingdom
of Valencia I learned the following facts from eye-wit-
nesses. A silk weaver kept a stallion and a mule in the
same stable. One night in winter the mule was taken ill,
rolled on the ground, and appeared ready to die. At
last it brought forth a foal, so well formed that the finest
marecould not have produced^ better. The stallion and
mule were left together during eight years, in whieh
time the latter brought forth five male and two female
foals*. Now the mule was half horse half ass; its off-
spring were half horse half mule. But, will it be said
that the latter, which were perfect horses, contained a
portion of the ass, which portion of ass might have
passed by the mule to become horse ? Most assuredly
no sensible person will say so. Nature has not instituted
the mule species ; and when in successive generations all
traces of the ass are effaced in the foals of the mule,

* A9 this fact has been questioned by some French theorists, from the
forced and miniature experiments of BufFon, it is not foreign to the pre-
sent subject to say that the writer of this note has also heard it from unim-
peachable eye-witnesses who were well acquainted with the whole circum-
stances, and that he knew a gentleman, an amateur mineralogist in Valen-
cia, who found one of the offspring of the mule the most serviceable horse
that he ever possessed. — Trans.

it

Notices respecting New Books, . 391

it is Nature which resumes her rights, and puts a limit
to a race of monsters.

The other circumstance which gave birth to the brilliant
idea of passage, is that which takes place when a mineral
is an aggregate of two simple species: such are the helio-
trope, composed of quartz and green earth; and prase, com-
posed of quartz and green schorl (rayonnante) [actinolite of
Kirwan and Jameson ; amphibole"* actinote of Haiiy and
Brogniart], It is at first a veiy great and irreparable error
to consider mixtures as species, the essence of which is
simplicity.

fTo be continued.]

LXXI. Notices respecting New Books,

X he Philosophical Transactions for the Year 1810, Part 1 1,
has just made its appearance. Its contents^ are: — Sup-
plement to the First and Second Part of the Paper of Ex-
periments for investigating the Cause of Coloured Con-
centric Rings between Object Glasses, and other Appearances
of a similar Nature. By William Herschel,LL.D. F.R.S. —
On the Parts of Trees primarily impaired by Age. In a
Letter from T. A. Knight, Esq. F.R.S. to the Rt. Hon. Sir
Joseph Banks, Bart. K.B. P.R.S. — On the Gizzards of
Grazing Birds. By Everard Home, Esq. F.R.S. — Obser-
vations on atmospherical Refraction as it affects astrono-
mical Observations ; in a Letter from S. Groombridge, Esq.
to the Rev. Nevil Maskelyne, D.D. F.R.S. Astronomer

* The union of amphibole (hornblende) with actinote (actynolite) is
another fact highly honourable to the study of crystallography. Haiiy an-
nounced his opinion of their identity, which was fully confirmed by M.
Laugier's analysis in the An. d'Hist. Xal. vol. v. p. 73.

Amphibole contains Actinote

Silica 4202 50-OQ

Oxide of iron 22-69 II <X>

Magnesia 1O90 19-25

Lime 9 80 975

Alumina 7-69 0-75

Oxide of manganese 115 0-50

Chromium 000 3-00

Potash 0O0 0-5O

Water and loss 515 5.25

10000 100*00

The object of this analysis being to compare the nature and proportion.*;
at the constituent principles of amphibole and actinote, between which cry-
stallography had found a perfect analogy, the comparative resuU was such,
that it appeared necessary to blend them together under the same species oi
mineral, the latter presenting only some new varieties of colour of the for-
mer.— Trans.

2B4 Roval.

392 Royal Society,

Royal. Communicated by the Astronomer Royal. — Extract
of a Letter from the Rev. John Brinkley, D.D. F.R.S.
Andrews Professor of Astronomy in the University of
Dublin, to the Rev. Nevil Maskelyne, D.D. F.R.S. Astro-
nomer Royal, on the annual Parallax of a Lyrae. — On the
Mode of Breeding of the Oviviviparous Shark, and on the
Aeration of the foetal Blood in different Classes of Animals.
By Everard Home, Esq F.R.S. — On Cystic Oxide, a new
Species of Urinary Calculus. By William Hyde Wol-
laston, M.D. Sec. R.S. — Researches on the oxymuriatic
Acid, its Nature and Combinations ; and on the Elements
of the muriatic Acid. With some Experiments on Sulphur
and Phosphorus, made in the Laboratory of the Roval In-
stitution. By H. Davy, Esq. Sec. R.S. Prof. Chem. R.I.
F.R.S. E. — Observations upon Luminous Animals. By J.
Macartney, Esq. Communicated by Everard Home, Esq.
F.R.S. — Observations and Experiments on Pus. By Geo.
Pearson, M.D. F.R S. — Presents received by the Royal So-
ciety from November 180Q to July 1810.

GEOGRAPHY.

Mr. Myers, of the Royal Military Academy, will shortly
complete an Introduction to Historical, Physical, and Poli-
tical Geography; accompanied with Maps, and adapted to
the higher Classes of Pupils, under both public and private
Tuition. Mr. M.'s inducement to the undertaking, and his
guide in its accomplishment, has been utility ; and to at-
tain this object he has condensed into one moderate-sized
Octavo Volume the most valuable matter of more extensive
Systems. In the construction of the Maps, particular
attention is paid to simplicity, perspicuity, and accuracy;
and it is presumed that these qualities, so essential in every
elementary Treatise, will be found to prevail, in a superior
degree, throughout the whole performance.

LXXII. Proceedings of Learned Societies.

ROYAL SOCIETY.

vJn the 22d of Nov. Dr. Wollaston read a paper iC On
some of the Combinations of oxymuriatic Gas and Oxygen,
and on the Chemical Relations of these Principles to
inflammable Bodies. " By H. Davy, Esq. Sec. R.S.

In this paper Mr. Davy details a great number of experi-
ments which he has made on the combinations of oxymu-
riatic gas and oxygen with the metals of the fixed alkalies,
the metals of the earths, and the common metals j with a

view

Royal Society. 393

view to illustrate the nature, properties, and combinations
of oxymuriatic gas, and its relations to inflammable bodies,
as compared with those of oxygen. He also offers some
general views and conclusions concerning the chemical
powers of different species of matter, and the proportions in
which they combine. And lastly, he concludes his paper
by some observations on the impropriety of the present
nomenclature, in reference to the oxymuriatic gas and its
combinations ; and proposes some concise modes of di-
stinguishing these novel bodies.

Mr. Davy made some previous experiments on the com-
binations of potassium and sodium with oxygen ; and of
potash and soda with water, from which he concludes that
those metals when burnt in oxygen gas are at their highest
state of oxygenation — and at their lowest, when in the state
of potash and soda. He also found that ignited potash
contains about 16 per cent, of water, and ignited soda 22*9
per cent.

The spontaneous inflammation of the metals of the fixed
alkalies in oxymuriatic gas, affords a proof of the intensity
of their attractions. In these operations, no water is se-
parated, but mere binary combinations formed ; the same
as those produced by igniting muriate of potash and soda.
Similar compounds are formed when dry potash and soda
are heated in oxymuriatic gas, and oxygen is evolved.

Mr. Davy mentions a simple mode by which pure sodium
may be obtained. It is by mixing common salt which has
been ignited to redness, with potassium, and exposing the
whole to a red heat in a glass tube or retort ; for every two
parts of potassium employed, one part of sodium is obtained.

As the muriates of lime, barytes and strontites remain
unaltered by any simple attractions, even at a white heat,
Mr. Davy conceived that these compounds consist merely
of the metallic bases of the earths in union with oxymu-
riatic gas, and the experiments he has made confirm this
conclusion. Thus when lime, barytes, &c. were heated in
oxymuriatic gas, oxvgen was expelled, and substances ex-
actly similar to the dry muriates were formed.

In operating on the metals, Mr. Davy employed green
glass retorts holdiug from three to six cubical inches of gas,
they were furnished with stop-cocks. The metal was first
introduced into the retort, it was then exhausted and filled
with oxymuriatic gas, the heat of a spirit lamp was em-
ployed in the processes. The products from arsenic, anti-
mony, and bismuth, were the butters of arsenic, antimony,
and bismuth j and on the addition of water, the white oxides

and

3Q4 New Engine.

and muriatic acid. Tin produced Libavius's liquor, mer-
cury, corrosive sublimate, silver and lead, horn silver, and
horn lead. Iron, a beautiful, volatile, crystallized substance
which gave the red muriate of iron on the addition of water.

Mr. Davy also found that oxvmuriatic gas decomposes
the metallic oxides at a heat below redness ; — those of the
volatile metals more easily than those of the fixed metals,
and protoxides more readily than peroxide?. Mr. Davy
notices two beautiful experiments on the agency of oxy-
muriatic gas on white oxide of arsenic, and black oxide of
iron* In these cases, no oxygen was evolved, the portion
separated from one part of the oxides combined with the
other part, and the products were butter of arsenic and
arsenic acid, and ferruginous sublimate and red oxide of iron.

Mr. Davy notices an experiment in which he decom-
posed the gray oxide of tin by muriatic acid gas. In this
case, water rapidly separated and Libavius's liquor was
formed.

Mr. Davy conceives that these new inquiries confirm all
the conclusions he has drawn in his recent paper on " Oxy-
muriatic Acid, &c."

LXXIII. Intelligence and Miscellaneous Articles.

^ NEW ENGINE.

An engine has been lately invented by Mr. Taylor of Hol-
well, Engineer to the Tavistock Canal, which may be put
into motion either by water or steam, without any alteration
in its construction or in any of its parts. It is extremely
simple, and may be erected at a moderate expense. Its
power when worked by water is, as in other hydraulic ma-
chines, in proportion to the quantity employed and height
of the fall. When steam is substituted, the area of the
piston determines the effect.

It may probably be a valuable machine in cases where a
falling stream may be had equal to useful purposes at one
period of the year, and deficient in a proper supply in dry
seasons. Many mines and manufactories are in this situa-
tion, and might by a single engine of this sort work un-
interruptedly, saving the expense of coal when the stream
of water was sufficient, and using the boiler only when the
supply of water fell short. It is of the kind of hydraulic
machines usually called Pressure Engines; various con-
structions of which have been attempted, but none have yet
been very successfully made, at least upon a large scale.

The

Meteor seen in Holland, 3{)5

The difficulty which has attended the opening and closing
valves of sufficient water-way, having presented great ob-
stacles to a regularity of movement, — this objection is
surmounted in this instance by the invention of a new
valve, which admits apertures of large size, and is opened
and closed with any required velocity, and is applicable to
the passage either of waier or steam.

To Mr, Tilloch.
Sir, — If you will please to communicate the following
fact through the medium of your very intelligent Magazine,
some of your readers will probably favour the public with
their opinions upon the subject.

On my passage from Rio de .Taniero to this place, on
Jjoard the ship Favorite, Capt. Atkinson, on July the 14th,
being in latitude 31° 56' and longitude per account 39° 30',
at six A.M., when below, felt a very singular sensation
which lasted near a minute. All below ran upon deck,
feeling the ship shake as if she was passing over a wreck,
rubbing very hard ; or as if some very heavy body was
rolled from one end of the ship to the other. To the officer
and people on deck the sensation was as if the ship was
going over a bar, touching, but not stopping ; this lasted
nearly the space of a minute. Some ran few the lead, which
was hove in the shortest time possible, — no bottom : others
sounded the pump, — no difference; — each looked astonished
and panic-struck. The sea was smooth, a gentle breeze
westerly, all sail set ; the ship was loaded with coffee. At
about seven A. M., an hour after, the same sensation was
felt, less sensible and of shorter duration. — Could it arise
from electricity ?

Any of your readers favouring the public with their
opinion, will much oblige

Your humble servant,

A Passknger.

MKTEOR SEEN IN HOLLAND.

Wall (on the Meuse}, Sept. 22.

On the 19th of this month, between the hours of five and
six in the evening, a luminous meteor appeared to the
south, and about the distance of a quarter of a league from
the small commune of Brezeau : persons who attentively
examined it assert that it was nearly a quarter of an hour
in collecting, floating over the place where it was fi** seen ;

and

396 Miinzo Parke.

^v

and that when all its parts had united, it appeared all at
once as a very considerable globe of fire, taking a northerly
direction : it spread terror amongst the inhabitants of the
village, who believed their houses would be burnt, and they
themselves perish. This globe was accompanied by a fright-
ful noise, which was heard at the distance of more than a
league and a half, and sometimes resembled the rolling of
a rapid chariot ; at others, the noise of rain driven by the
wind. It was followed by a very thick fog, and carried up
from the ground every thing it met in its passage. In
crossing a river it absorbed water, which soon afterwards
fell in rain. It wandered for some time near the village.

One thing certain is, that the roof of a house was thrown
down, which is the only trace it has left. It was accom-
panied and followed by an abundant rain, much lightning,
and loud claps of thunder. Continuing in the same direc-
tion, it suddenly turned into a column of fire, which, with
the fog, rose towards the heavens. This made many per-
sons believe the fog was smoke. It remained about a quar-
ter of an hour in this state, a quarter of a league to the
north of the village, and at a short distance from the forest
of Beaulieu. This column now sunk a little, and at last it
suddenly disappeared, leaving a thick fog which had no
smell. This phaenomenon lasted three quarters of an hour,
and travelled over the space of half a league*

MR. MUNGO PAKKE.

November 8, 1810.

The painful incertitude respecting the fate of this adven-
turous character yet exists. An account has however been
received in town this week, which again revives the almost
extinguished spark of hope. It is stated by a very respecta-
ble gentleman, Capt. Davison, commander of a vessel of
Messrs. Anderson, lately returned from the Coast of Africa,
that on the 26th of July last a Moor arrived from the in-
terior at Bunce Island, in the river Sierra Leone, from whom
the following particulars were learned. — In January 1809
Mr. Parke was seen by the Moor, at a short distance from
Tombuctoo, in a state of very bad health, in one of the
natives' huts, after having been imprisoned by a native
chief. He was, however, all that time at liberty, and had
received permission to proceed on his route. Capt. Davison
interrogated the man frequently and minutely ; and, from
the consistency of his answers, entertains no doubt of the
correctness of his narrative.

To

Improvement in writing and printing Numbers, 397

To Mr. Tilloch.
Sir, — Should the following idea be considered by you
as an 'improvement in writing and printing numbers con-
sisting of many digits, its insertion in your publication will
confer an honour on, Sir,

Your very humble servant,

Spitalfields, 19th Nov. 1810. A ReIRTALP.

When a number such as 69,470,600,078,406,300,097
presents itself, though pointed in periods of three figures,
the manner of expressing it in words does not immediately
occur to the mind. The mode I would beg leave to offer
as an improvement is, besides pointing it in periods of
three figures, to place one accent over the seventh figure,
or millions; two accents over the 13th figure, or billions ;
and so on, increasing the accents at every myriad, thus : —

69,470,600,078,406,300,097, — by which we can perceive
at once that the two first figures denote trillions, without
the usual mode of reckoning according to the Numeration
Table.

EARTHQUAKE.

Extract of a letter, dated St. Michael (Azores), August
24. — " One of those dreadful phenomena never witnessed
in your country has plunged many here in unspeakable
wretchedness and affliction, and continues to occasion great
terror to all the inhabitants of this island. On the I lth of
August, at ten P. M. slight shocks of an earthquake were
felt at intervals of a few minutes for four hours. During
this time the inhabitants, under the influence of alarm for
their personal safety as well as property, were running to
and fro in the greatest distress. Between two and three a
dreadful rocking was experienced throughout the whole
island; several houses, unable to resist its violence, were
thrown down, and many others were greatly damaged ;
and such persons as sought safety in the open air were
dashed to the ground. Hitherto che calamity had been
confined in its effects, and though great injury had been
sustained, we had to congratulate ourselves on the loss of
few lives ; but we were yet to witness a most dreadful spec-
tacle. On the 12th at mid-day, a hollow-rumbling sound
was heard, the clouds gathered, and the wind was hushed
into silence ; therocking returned, and in a few minutes
after the village of Gozas, situated on a plain, comprising
22 houses, was swallowed up, and in the spot where it stood
a lake of boiling water gushed forth. Many of the un-
fortunate inhabitants, who had previously retired to the
elevated ground,^ beheld the sight with a degree of horror

and

398 Society for Relief of Widows of Medical Men.

and amazement which enchained all their faculties; their
whole property swept away in a few minutes, and in the
place where their once beautiful gardens and flourishing
orchards stood, nought now appeared but a vast expanse of
water ! About thirty-two persons, it is calculated, have
lost their lives by this awful and calamitous event, and cat-
tle and property to a considerable amount destroyed. A
great degree of alarm continues to pervade the whole island,
as on the east side an orifice has been discovered, resem-
bling the crater of a volcano, and out of which flames oc-
casionally burst through. Hitherto they have been unac-
companied by any ejection of volcanic matter. "

On Wednesday, October the 3d, the Society for Relief
of Widows and Orphans of Medical Men, in London and
its Vicinity, held their Half-yearly General Court at the
usual Place of Meeting — the Graves Inn Coffee-House,
Holborn ; at which time their Annual Election of Officers
and Directors took place, and the following were the ar-
rangements made for the ensuing Year, viz.

PATRON,

t His Royal Highness the Duke of Kent,

PRESIDENT,

James Ware, Esq.

VICE-PRESIDENTS,

Sir F. Mil man, Bart. Dr. Squire

Mr. Heaviside

Dr. Garthshore

Dr. Dennison

Mr. Moore

Dr. Lettsom

Mr. Howard

Mr. Nevinson

Dr. Blane

Sir W. Blizard

TREASURERS,

Mr. Rendall.

Dr. Denman, Dr. J. Sims, Dr.

, Dennison.

DIRECTORS,

Physicians.

Dr. Temple

Dr. Walshman

Dr. R. Pearson

Dr. Stone

Dr. S. H. Jackson

Dr. Croft.

Dr. Frampton

Dr. Shaw

Surgeons.

Mr. Ed. Browne

Mr. Steele

Mr. Ramsden

Mr. Mathias

Mr. H. L. Thomas

Mr. Lewis,

Mr. Milward

Mr. C. M. Clarke

Apotheraries.

Mr. Field Mr.

Coates Mr. Starr

Mr. Pilliner

Mr. Upton Mr.

Seaton Mr. Malim

Mr. Moore, Jun.

TRUSTEES,

Right Hon. Marquis Townshend, President of the Society
of Antiquaries ;

Right

List of Patents for new Inventions, 399

Right Hon. Sir J. Banks, Bart. K.B. President of the Royal
Society ;
Isaac Hawkins Browne, Esq. M.P. F.R.S.
* James Ware, Esq.

SECRETARY,

Mr. William Chamberlaine.

SOLICITOR,

Okey Belfour, Esq.

COLLECTOR,

Mr. George Hunt, No. 2, Cock- Court, Ludgate Hill.

BANKERS,

Messrs. Vere and Co., No. 77? Lombard-Street.

HONORARY MEMBERS,

Right Honourable Marquis Townshend,
Right Honourable Sir J. Banks, Bart. K.B.
Isaac Hawkins Browne, Esq. M.P.

Jame Vere, Esq. William Morgan, Esq.

Sir William Watson Charles Chevalier, Esq.

Okey Belfour, Esq. Sir Frederick Baker, Bart.

LIST OF PATENTS FOR NEW INVENTIONS.

To Edmund Griffith, of the city of Bristol, Esq. for cer-
tain improvements in the manufacture of soap for the
purpose of washing with sea- water, with hard water, and
with other waters. — Oct. 8, 1810.

To Richard Woodman, of Hammersmith, in the county
of Middlesex, boot- and shoe-maker, for his method of
manufacturing all kinds of boots, shoes, and other articles.
—Oct. 8.

To Edward Mauley, of UtTculme, in the county of Devon,
clerk, for his apparatus for writing. — Oct. 8.

To John Fraser, collector of natural history, now of
Sloane Square, in the county of Middlesex, for his dis-
covery of certain vegetables, and a way of preparing the
same, so as they may be usefully applied in the manufac-
turing of hats and bonnets, chair-bottoms, and baskets, and
for other articles or purposes. — Oct. 15.

To John Wheatley, of Greenwich, in the county of
Kent, coach-builder, for his improved axle-tree for wheels
of carriages, and also improved wrought- or cast-iron boxes
and cast-iron stocks to receive the spokes of the wheels. —
Oct. 15.

To Thomas Mann, of Bradford, in the county of York,
stuff-merchant, for certain improvements in the construction
of artificial legs. — Oct. 31.

METEORO-

400

Meteorology,

meteorological table,
By Mr. Carey, of the Strand,
For November 1810.

Thermometer.

Height of

the Barom.

Inches.

eureesofDry-
essby Leslie's
[ygrometer.

Days of
Month.

]

3
o

z

c **j

■J bo

Weather.

oo

"

Q C 3h

Oct. 27

44

46°

39°

30*05

31

Cloudy

28

47

49

40

29-62

0

Rain

29

38

43

33

'65

25

^a!r [the night

30

36

44

32

•89

38

r air, with snow i»

31

33

44

43

'95

25

Cloudy

Nov. 1

44

47

40

'63

22

Cloudy

2

39

47

41

•80

20

Cloudy

3

42

46

41

•87

0

Rain

4

42

46

35

•84

10

Showery

5

33

41

39

•65

25

Cloudy

6

40

43

37

•12

10

Showery

7

38

42

37

28*92

5

Showery

8

40

46

37

29*00

0

JRain

9

36

51

42

•47

21

Fair

10

41

48

43

28*50

0

Stormy

11

43

44

44

29*30

5

Cloudy

12

43

45

40

'61

22

Fair

13

40

45

37

30*10

25

Fair

14

39

42

43

29'93

25

Rain

15

51

54

47

•50

15

Fail-

16

52

57

50

•25

26

Fair

17

47

51

44

•40

22

Fair

18

43

48

47

'55

16

Fair

19

47 '

51

46

'56

5

Rain

20

44

47

50

•60

10

Cloudy

21

53

56

47

•40

0

Rain

22

47

47

45

'65

0

Stormy

23

45

53

47

•76

21

Fair

24

47

50

46

'65

0

Rain

25

44

49

41

'56

10

Showery

26

43

44

41

•25

0

Rain

N.B. The Barometer's height is taken atone o'clock.

t 401 ]

LXXIV. Theoretical Suggestions for the Improvement of
Practical Surgery. By A Correspondent.

1st. In that part of the operation of amputation when the
hone is to be sawed through, it appears to me that a steady-
support to the bone would materially facilitate and secure
the correct action of the saw : In the present mode, when
the only means of steadying the bone and resistance to the
action of the saw is made by the grasp and manual force of
frequently agitated assistants, the difficulty of dividing the
bone, without splintering and ruggedness, is very consider-
able. Might not a perpendicular prop from the floor, with
a semicircular hollow to receive the bone, be of great effect
in rendering it steady ? When a retractor is used, might
not such prop form part of that instrument? Carpenters,
when they saw timber, always take care to make it steady
previous to the application of the saw ; Why should not
the same mode be u*ed when sawing the bones of the arm
or leg? The soft parts could not be injured by such a me-
thod ; as by the present mode of amputation, by double in-
cision, a considerable length of bone is bared before the saw
is used, and why might not the proposed support be applied
to that part ?

2d. In the operation of trepaning the skull, when the
scalp is sufficiently removed, it is essential to remove just
so much of the pericranium and no more, as the head of
the trephine will include; because the cranium, when de-
nuded of its pericranium, will, like other bones denuded of
their periosteum, grow carious. This part of the operation
is now generally performed by an instrument called a
raspatory, or by scraping the skull with a small scalpel.
Would not this be performed much more complete bv
having a head adjusted to the trephine handle, precisely the
dimensions of the serrated head, and which head would
have a circular cutting edge, with a species of concave plane
or scraper within it? One turn of such an instrument as I
can imagine, and as any person could easily contrive, but
which I find difficult to describe bywords, would completely
remove the exact portion of pericranium and no more*.

3d. Were surgeons to make themselves acquainted with
tin implements ur;ed in different mechanical professions, it
is possible some valuable additions might be made to the

have reason to believe that there is such an instrument as the one
above .Alluded to. It was said to h^ve been the invention of Mr. Henry
Cline, juoii

Vol. 30. No. 152. Dec, 1810. 2 C present

402 Theoretical Suggestions for the Improvement

present instruments of surgery. They should likewise ob-
serve, with a professional eye, the various mechanieai im-
provements which are daily taking place. Might not the
circular saw be introduced in some operations ? Small cir-
cular saws, cutters, or wheels with toothed edges -of dif-
ferent sizes and thickness, might perhaps be used with ef-
fect in insulating and removing the depressed angular pieces
of bone which occur in fractures of the skull. When the
trephine is inadmissible, a circular cutter applied to the
edge of the fracture, might, if used with proper precaution,
cut away the bone with safety, and make a space sufficient
to admit the elevator. Such a cutter might be turned by
the hand, as great velocity would be dangerous. A method
could easily be contrived to apply such an instrument with
the requisite steadiness to the part.

4th. The centre point of the trephine necessarily protrudes
beyond its teeth ; in consequence of which, when the inex-
perienced operator neglects too long to remove it, the most
serious effects are sure to follow. Might not this be easily
prevented by having a shoulder, as mechanics term it, to
surround the point, just so far down from the extremity of
the point, as to permit the saw to fix itself, and no more?

5th. Would not a contrivance be useful, in trepanning
the skull, to fix the head in the most favourable posture?

6lh. The best shape for the points of one description of
piercing instruments has, 1 think, never yet been exactly
ascertained; and it is certainly a question of considerable
importance. I mean those piercing instruments, where
breadth of instrument is requisite immediately on insertion ;
for, as to common needles, and other small instruments
merely for piercing, it is evident the more acute we make
their points, the better. In some instruments, however,
where a point is merely necessary for their insertion, when
that point is much prolonged beyond the efficient part of the
instrument, it becomes injurious: What point will suit such
an instrument best? Is it well ascertained that the drill or
shear point is the most advantageous ? Ft' the point formed
an acute angle, sloped to one side, would it not answer as
well? What is the proper angle for such a point? Me-
chanics pierce brass, copper, and steel with drills of different
shapes: May not ihere be an appropriate point for piercing
animal membranes ? The French discovered by experi-
ments (fatal experiments!) that the descending blade of the
guillotine cut best when sloped to a certain angle. How-
ever confident wc may be in our opinion, to experiment
we should always have recourse, whui possible; and in sa-
tisfying

of Practical Surgery. 403

tisfying our present doubts, it is very possible. An appa-
ratus might easily be contrived for the purpose. All that
is requisite is, a piece of brass, about four inches long and
two inches square, supported by two or more feet, and per-
forated longitudinally, lo admit a thick steel pin, which
pin is to be fitted to the perforation in the brass, so as to
move very freely, and to exceed the brass about two inches
or more in length. On the upper end of this pin, I would
have a small flat piece of brass fixed, capable of holding
weights ; and in the lower end, a hole made, into which the
different shaped points on which we are desirous to make
experiments are to be fixed, similarly to the shifting feet of
common compasses. Immediately below this pin I would
place a species of drum, consisting of a small box, with
bladder or other elastic substance stretched over it to imitate
ihe animal tunics. Now it is evident, that by placing dif-
ferent weights on the upper end of the pin, until the point
we are experimenting on pierce the stretched bladder, we
may be able exactly to appreciate the comparative advantage
of the different kinds of pointv

7th. The operation of couching frequently fails, from the
cataract or opake crystalline lens being of a soft consistency;
which the couching needle, instead of depressing, passes
through and divides. If the broad part which is, I believe,
frequently used in depression, were made concave so as to
fit the convex edge of the lens, might it not in some degree
remedy this evil ?

8th. Considering that the majority of calculi in the blad-
der are more or less spherical, it appears to me that the
forceps now used in lithotomy is not of the most advan-
tageous construction. By each side of the beak of the
usual forceps being concave, with an oval hole at the bot-
tom of the concavity, similar to the forceps once used in
extracting polypi, the edges of which holeA and the sides
of the concavity, might have teeth, Would it not be more
iikely to lay hold of even an irregularly spherical calculus
than the forceps at present used, with toothed beaks and
flat sides ? and which seems better contrived for crushing
a soft calculus to pieces, than for holding it fast and with-
drawing it whole.

9th. Grown bold by practice, I shall now venture, as my
last suggestion, to propose another kind of forceps for ex-
tracting the stone. Let us suppose a forceps with the beaks
formed of two narrow elliptical rims, jointed so as in some
degree, by tjie pressure upon a calculus, to conform them-
selves lo its size. To the edges of these rims I would at-
2 C 2 taefi

404: Researches on the muriatic Acid

tach a piece of linen or leather, forming- to each beak a
small purse or sack. When tluse forceps should he closed
upon a calculus in the least spherical, the steel rims would
extend to let it pass, and it would then be completely sur-
rounded. The advantages of this forceps would be, that
the calculus could not escape: and the bulk to be with-
drawn through the wound, would be very little more than
the exact bulk of the calculus.

LXXV. Researches on the oxymuriatic Acid, its Nature and
Combinations ; and on the Elements of the muriatic Acid.
With some Experiments on Sulphur end Phosphorus,
made in the Laboratory of the Royal Institution. By
H. Davy, Esq. Sec. R.S. Prof. Chem. R.L F.R.S.E. .

[Concluded from p. 361.]

It is extremely probable that there are many combinations
of the oxymuriatic acid with inflammable bodies which
have not been yet investigated. With phosphorus it seems
capable of combining in at least three proportions ; the
phosphuretted muriatic acid of Gav-Lussac and Thenard is
the compound containing the maximum of phosphorus.
The crystalline phosphoric sublimate, and the liquor formed
by the combustion of phosphorus in oxymuriatic acid gas,
disengage no phosphorus by the action of water ; the
sublimate, as I have already mentioned, affords phosphoric
and muriatic acid ; and the liquid, I believe only phos-
phorous acid and muriatic acid.

The sublimate from the boracic basis gives, I believe,
only boracic and muriatic acid, and may be regarded as
boracium acidified by oxymuriatic acid.

It is evident, that whenever an oxymuriatic combination
is decomposed by water, the oxide or acid or alkali or oxi-
dated body formed must be in the same proportion as the
muriatic acid gas, as the oxygen and hydrogen must bear
the same relation to each other; and experiments upon
these compounds will prohablv afford simple modes of as-
certaining the proportions of the elements, in the different
oxides, acids, and alkaline earths.

If, according to the ingenious idea of Mr. Dalton, hy-
drogen be considered as one in weight, in the proportion it
exists in water, then oxygen will be nearly 7*5 ; and as-
suming that potash is composed of one proportion of oxy-
gen, and gne of potassium, then potash will be 48, and

potassium

in its different States. 405

potassium * about 40-5 ; and from an experiment which I
have detailed in the last Bakerian lecture, on the combus-
tion of potassium in muriatic acic! gas, oxymurialic acid will
be represented by 32*9, and muriatic acid gas, of course,
bv 33*9 ; and this estimation agrees with the specific gravity
of oxvmuriatic acid gas, and muriatic aeid gas. From my
experiments, 100 cubical inches or oxy muriatic acid gas
weigh, the reductions being made for the mean temperature
and pressure, 74*5 grains ; whereas by estimation they should
weigh 74'6*. Muriatic acid gas I find weighs, under like
circumstances, in the quantity of 100 cubic inches, 39
grains; by estimation it should weigh 38*4 grains.

It is easy from these data, knowing the composition of
any dry muriate, to ascertain the quantity t- of oxide or of
acid it would furnish by the action of water, and consequently
the quantity of oxygen with which the inflammable matter
will combine f.

In considering the dry muriates, as compounds of oxy-
muriatic acid and inflammable bodies; the argument that I
have used in the last Bakerian lecture, to show that potas-
sium does not form hydrate of potash by combustion, ig
considerably strengthened ; for from the quantity of oxy-
muriatic acid the metal requires to produce a muriate, it
seems to be shown that it is the simplest known form of the
alkaline matter. This I think approaches to an experi-
mentum crucis. Potash made by alcohol, and that has

* Supposing potash to contain nearly 15'6 per cent, of oxygen.

f I have stated in the last Bakerian lecture, that during the decomposition
of the amalgam from ammonia, one in volume of hydrogen to two of am-
monia is evolved: it is remarkable, that whatever theory of the nature of
this extraordinary compound he adopted, there will be a happy coincidence
as to definite proportions. If it be supposed that the hydrogen arises from
the decomposition of water; then the oxygen that must be assumed to exist
in ammonia, will be exactly bufllcient to neutralize the hydrogen, in an
equal volume of muriatic acid; or if it be said that ammonium is a com-
pound of two of ammonia and one of hydrogen in volume, then equal volumes
of muriatic acid gas aud ammonia will produce the same compound as oxv-
muriatic acid and ammonium, supposing they could be immediately com-
bined. I once thought that the phenomena of metallization might be ex-
plained according to a modified phlogistic theory, by supposing three dif-
ferent classes of metallic bodies: First, The metal of ammonia, in which
hydrogen was so loosely combinued as to be separable with great ease, and
whirl., in consequence of the small affinity of the basis for water, it had little
tendency to combine with oxygen. The second, the metals of the alkalies
and alkaline earths, in whicli the hydrogen was more firmly combined, but
in combustion, forming writer capable of being separated from the basis.
And, thirdly, the metals of the earths and common metals, in which the
hydrogen was more intimately combined-, producing by union with oxygen,
water not separable by any new attractions. '1 'lie phenomena of theaction
of potassium and sodium upon muriatic acid, referred to in the text, seem
however to overturn these speculation so far as they concern the metal*
from the fixed alkalies.

2 C 3 been

406 Researches on the muriatic Acid

been heated to redness, appears to be a hydrate of potash,
whilst the potash formed by the combustion of potassium
must be considered as a pure metallic oxide, which requires
about 19 per cent, of water to convert into a hydrat.

Amongst all the known combustible bodies, charcoal is
the only one which does not combine directly with oxy-
muriatic acid gas ; and yet there is reason for believing that
this combination may be formed by the intermedium of
hydrogen. I am inclined to consider the oily substance
produced by the action of oxymuriatic acid gas, and olefiant
gas, as a ternary compound of these bodies; for they com-
bine nearly in equal volumes; and 1 find that, by the action
of potassium upon the oil so produced, muriate of potash
is formed, and gaseous matter, which I have not vet been
able to collect in sufficient quantity to decide upon its na-
ture, is formed. Artificial camphor, and muriatic ether, as
is probable from the ingenious experiments of M. Gehlen
and M. Thenard, must be combinations of a similar kind,
one probably with more hydrogen, aud the other with more
carbon.

One of the greatest problems in oeconomical chemistry,
is the decomposition of the muriates of soda and potash.
The solution of this problem will, perhaps, be facilitated by
these new views. The affinity of potassium and sodium
for oxymuriatic acid is very strong ; but so likewise is their
attraction for oxygen, and the affinity of their oxides for
water. The affinities of oxymuriatic acid tras for hydrogen,
and of muriatic acid gas for water, are likewise of a power-
ful kind. Water, therefore, should be present in all cases,
when it is intended to attempt to produce alkali. Jt is not
difficult after these views to explain the decomposition of
common salt, by aluminous or siliceous substances, which,
as it has been long known, act only when they contain wa-
ter. In these cases the sodium may be conceived to com-
bine with the oxygen of the water and with the earth, to
form a vitreous compound ; and the oxymuriatic acid to
unite with the hydrogen of the water, forming muriatic acid
gas.

It is also easy, according to these new ideas, to explain
the decomposition of salt by moistened litharge, the theory
of which has so much perplexed the most acute chemists.
It may be conceived to be an instance of compound affinity :
the oxymuriatic acid is attracted by the lead, and the sodium
combines with the oxygen of the litharge and with water to
form hydrat of soda, which gradually attracts carbonic acid
from the air.

As

in its different States. 407

As iron has a strong affinity for oxymnriatic acid, T at-
tempted to procure soda by passing steam over a mixture
or' iron filings, and muriate of soda intensely heated: and
in this way I succeeded in decomposing some or' the salt:
hydrogen came over: a little hydrate of soda was formed;
and muriate of iron was produced.

It does not seem improbable, supposing the views that
have beeen developed accurate, that, by complex affinities,
even potassium and sodium in their metallic form may be
procured from their oxymuriatic combinations: for this
purpose the oxymuriatic acid should be attracted by one
substance, and the alkaline metals by another; and such
bodies should be selected for the experiment, as would pro-
duce compounds differing considerably in degree of vola-
tility.

I cannot conclude the subject of the application of these
doctrines, without asking permission to direct the attention
of the Society to some of the theoretical relations of the
facts noticed in the preceding pages.

That a body principally composed of oxymuriatic acid
and ammonia, two substances which have been generally
conceived incapable of existing together, should be so dif-
ficult of decomposition, as to be scarcely affected by any of
the agents of chemistry, is a phcenomenon of a perfectly
new kind. Three bodies, two of which are permanent
gases, and the other of which is considerably volatile, form
in this instance a substance neither fusible nor volatile, at a
white heat. It could not have been expected that ammonia
would remain fixed at such a temperature ; but that it
should remain fixed in combination with oxymuriatic acid,
would have appeared incredible, according to all the existing
analogies of chemistry. The experiments on which these
conclusions are founded, are, however, uniform in their re-
sults: and it is easy to repeat them. They seem to show,
that the common chemical proposition, that complexity of
composition is uniformly connected with facility of decom-
position, is not well founded. The compound of oxymu-
riatic acid, phosphorus, and ammonia, resembles an oxide,
such as silex, or that of columbium in its general chemical
characters, and is as refractorv when treated by common
re-agents ; and except by the effects of combustion, or the
agency of fused potash, its nature could not be detected by
any of the usual methods of analysis. Is it not likely, rea-
soning from these circumstances, that many of the sub-
stances, now supposed to be elementary, may be reduced
into simpler forms of matter? and that an intense attrac-

2 C 4 tfodj

408 Researches on

tion, and an equilibrium of attraction, may give to a com-
pound, containing several constituents, that refractory cha-
racter, which is generally attributed to unity of constitution,
or to the homogeneous nature of its parts?

Besides the compound of the phosphoric sublimate and
ammonia, and the other analogous compounds which have
been referred to, it is probable that other compounds of like
nature may be formed of the oxides, alkalies, and earths,
with the oxymuriatic combinations, or of the oxymuriatic
compounds with each other; and should this be the case,
the more refined analogies of chemical philosophy will be
extended by these new, and, as it would seem at first view,
contradictory facts. For if, as 1 have siid, oxymuriatic
acid gas be referred to the same class of bodies as oxygen
gas, then, as oxygen, is not an acid, but forms acids by
combining with certain inflammable bodies, so oxymuriatic
acid, by uniting to similar substances, may be conceived to
form either acids, which is the case when it combines with
hydrogen, or compounds like acids or oxides, capable of
forming neutral combinations, as in the instances of the
oxymuriales of phosphorus and tin.

Like oxygen, oxymuriatic acid is attracted by the positive
surface in Voltaic combinations ; and on the hypothesis of
the connexion of chemical attraction with electrical powers,
•all its energies of combination correspond with those of a
body supposed to be negative in a high degree.

And in most of its compounds, except those containing
the alkaline metals, which may be conceived in the highest
degree positive, and the metals with which it forms inso-
luble compounds, it seems still to retain its negative char
racter.

I shall occupy the time of the Society for a few minutes
longer only, for the purpose of detailing a few observations
connected with the Bakerian lectures, delivered in 'the two
last years; particularly those parts of them relating to sul-
phur and phosphorus, which new and more minute inquiries
have enabled me to correct or extend.

J have already mentioned that there are considerable dif-
ferences in the results of experiments, made on the action
of potassium, on sulphur and phosphorus, and their com-
binations with hydrogen, according to different circumstances
of the process. 1 shall now refer to such of these circum-
stances as I have been able fully to investigate.

The able researches of Dr. Thomson have shown that
sulphur, in its usual state, contains small quantities of acid
matter; and though, in my first experiments, I conceived

* that

Sulphur and Phosphorus. 409

that by employing crystallized native Sulphur, which had
been recently sublimed in nitrogen, I should avoid the pre-
sence of any foreign matter, yet I am inclined to believe
that this is not the case; for bv subliming some similar
sulphur in nitrogen, I find that litmus paper placed in the
upper part of the retort is slightly reddened.

When potassium is made To unite with sulphur, if the
retort employed is not lined with sulphur, some of the po-
tassium is destroyed by acting upon the glass ; and when
large quantities of sulphur are used, it is very difficult to
decompose the whole of the sulphuret of potassium by an
acid ; sulphuretted hydrogen likewise is soluble in muriatic
acid : and this circumstance led me to under-rate the quan-
tity of sulphuretted hydrogen given oft* in experiments of
this kind *.

In acting upon sulphuretted hydrogen by potassium in my
early experiments, I used large quantities of the gas and of
the metal ; and in these cases I have reason to believe that
the violence of the combustion occasioned the decomposi-
tion of a considerable quantity of the gas ; and, in conse-r
quence, led me to form erroneous conclusions concerning
the nature of this curious operation.

Jn all late experiments in which sulphur or sulphuretted
hydrogen was concerned, I have used muriatic acid saliw
rated with sulphuretted hydrogen over mercury. I have
employed sulphur distilled from iron pyrites in vacuo, which
did not in the slightest degree affect litmus paper, and [
have combined it with potassium in retorts of green-glass,
or plate- glass lined with sulphur and filled with very pure
nitrogen or hydrogen. In making potassium act upon sul-
phuretted hydrogen, I have employed the gas only in the
quantities of from one to three cubical inches, and have made
the combination in narrow curved tubes of green-glass over
dry mercury. With all these precautions, and after having
made a great number of experiments, I am notable to gain
perfectly uniform rtsuks. Yet there is a sufficient corre-
spondence between them to enable me to form conclusions,
whieh I may venture to say cannot be far from the truth.
When one grain of potassium, which would give by the.

* This circumstance has been '.jointed out by MM. Gay Luaac and
T/heoard, i° :1 ' aPL-r Pr»nted in the Journal de Physique for December, in
which there gentlenler! endeavour to show that, whether potassium ha? been
acted upon by large or un II qiUU hi- ot suiplnn ard under all circum-
stances, it evolves a quantity 01 gas exactly e^aal to that which it produces
by the action of water. I ha\ been able \o gain no results i > precise on
this subject. I have in another place (the same journal in whieh their me-
nioir has appeared) offered some observations on their inquiries.

action

410 Researches on

action of water about one cubical inch and -j-g- of hydrogen is
made to act upon about half a grain of sulphur, some sulphur
sublimes during the combination, which always takes place
with heat and light, and from t't t0 tV °* a cubical inch of
sulphuretted hydrogen is evolved. The compound acted
on by muriatic acid, saturated with sulphuretted hydrogen,
affords from -j90- to -f-^ of a cubical inch of pure sulphuretted
hydrogen.

When more sulphur is used so as to be from twice to
ten times the weight of the potassium, the quantity of sul-
phuretted hydrogen evolved by the action of the acid, is
from T70- to T9y-; but if heat be applied to the combination,
so as to drive- off the superfluous sulphur, the quantity of
gas collected is very little inferior to that produced from the
combination in which a small proportion of sulphur is used;
and I am inclined to believe, from the phenomena pre-
sented in a great number of experiments, that sulphur and
potassium, when heated together under common circum-
stances, combine only in one proportion, in which the metal
is to the sulphur nearly as three to one in weight; and in
which the quantities are such that the compound burns into
neutral sulphate of potash.

When a grain of potassium is made to act upon about
J'l cubical mches of sulphuretted hydrogen, all the hydro-
gen is set free, and a sulphuret of potassium containing one-
fourth of sulphur is formed, exactly the same as that produced
by the immediate combination of sulphur and the metal.

When sulphuretted hydrogen is employed in larger quan-
tities, there is an absorption of this gas, and a volume is
taken up about equal to the quantity of hydrogen disen-
gaged, and a compound of sulphuretted hydrogen and sul-
phuret of potash is formed, which gives sulphuretted hy-
drogen by the action of an acid, nearly double in quantity
to that given by the sulphuret of potassium.

From a number of experiments I am inclined to believe
that potassium and phosphorus, in whatever quantities they
are heated together, combine only in one proportion, a grain
of potassium requiring about f of a grain of phosphorus to
form a phosphuret; which when acted upon by muriatic
acid, produces from -*f to ±% of a cubical inch of phosphu-
ret ted hydrogen.

Haifa gram of potassium decomposes nearly three cubical
inches of plmsphuretted hydrogen, and sets free rather more
than four cubical inches of hydrogen ; and the phosphuret
formed seems to be of the same kind as that produced by
direct combination of the metal with phosphorus.

if,

Sulphur and Phosphorus, 41 i

If, according to Mr. Dalton's ideas of proportion, the
quantity in which sulphur enters into its combinations were
to be deduced from its union with potassium, in which it
seems to form about one- fourth the weight of the com-
pound, the number representing it would be"^3*5. I have
lately weighed sulphuretted hydrogen and sulphureous acid
gas, with great care : the specific gravity of the first at mean
temperature and pressure, from my experiments, is 106*45,
which differs very little from the estimation of Mr. Kirwan :
that of sulphureous acid gas I find is COQ67- Sulphuretted
hydrogen, as I have shown, contains an equal volume of
hydrogen; and on this datum the number representing sul-
phur is 13*4. I have, never been able to burn sulphur in
oxygen without forming sulphuric acid in small quantities;
but in several experiments I have obtained from 02 to 98
parts of sulphureous acid from 100 of oxygen in volume ;
from which I am inclined to believe, that sulphureous acid
consists of sulphur dissolved in an equal volume of oxvgcn ;
which would give the number as 13-/ * nearly, considering
the acid gas as containing one proportion of sulphur, and
two of oxygen; and these estimations do not differ from
each other materially.

I have made several experiments on the combustion of
phosphorus in oxygen gas. From the most accurate, I am
inclined to conclude that 25 of phosphorus absorb in com-
bustion about 34 of oxygen in weight : and considering
phosphoric acid as composed of three proportions of oxy-
gen and one of phosphorus, the number representing phos-
phorus will be about lG'5, which is not very remote from
the number that may be deduced from the composition of
phosphuret of potassium.

The numbers which represent the proportions in which
lulphur and phosphorus unite with other bodies, are such,
as do not exclude the existence of combined portions of
oxygen and hydrogen in their constitution ; hut it may be
questioned, whether the opinion which I formed, that the

* The estimation from the composition of sulphuretted hydrogen, must
be considered as most accurate, and that from the formation of the suJphurct
of potassium as least accurate: for it was only by combining sulphur and
potassium in small proportions, and ascertaining in what cases uncombined
sulphur could be distilled from the compound, that I gained my conclusions
concerning the composition of the sulphuret of potassium.

In the last Bakerian lecture, I have estimated the specific gravity of sul-
phuretted hydrogen at 35 grains the ICO cubical inches, which was not far
from the mean between the estimations of Mr. Kirwan and Mr. TI,
According to this last experiment, sulphuretted hydrogen is composed of
one proportion of hydrogen, represented by 1, and one of sulphur rep; e-
«cnted by 13 4.

inflami.

412 ( Researches on Sulphur and Phosphorus,

inflammable o;as disengaged from them by electricity, is
necessary to the peculiar form in which these bodies exist,
is not erroneous. Phosphorus, as I have stated in the last
Bakerian lecture, is capable of forming a solid hydruret:
and a part oF the sulphur distilled from iron pyrites is
visually of a soft consistence, and emits the smell of sul-
phuretted hydrogen, and probably contains that body. It
is not unlikely, that in all cases, phosphorus and sulphur
contain small quantities of the hydrurets oF phosphorus
and sulphur; fchd the production oF a minute portion of
sulphuric acid in the blow combustion of sulphur, is pro-
bably connected with the production of water. Though
the pure oxides of sulphur and phosphorus have never been
obtained, yet irom the doctrine of definite proportions, these
bodies ought, under, certain circumstances, to be formed.
And I am inclined to believe, that they sometimes exist in
minute quantities in common phosphorus and sulphur,
and with hydrogen give to them their variable properties.

The colours of different specimens of phosphorus, as well as
of sulphur, differ considerably ; the red colour of phosphorus
as it is commonly prepared, is probably owing to a slight
mixture of oxide. Common roll sulphur is of a very pale
yellow, the Sicilian sulphur of an orange colour, and the
sulphur distilled from iron pyrites in vacuo, which arose in
the last period of the process, of a pale yellowish-green
colour. All the late experiments that I have made, as well
as mv former researches, induce me to suspect a notable
proportion of oxygen in Sicilian sulphur, which is probably
owing to the presence of oxide of sulphur, which may give
rise to sulphuric acid in distillation, or to sulphuric acid
itself.

Conceiving that, if definite proportions of oxygen and
hydrogen existed in sulphur and phosphorus, they ought to
be manifested in the agency of oxy muriatic acid gas on
these bodies, I made some experiments on the results of
these operations. In the first trial, on the combination of
sulphur with oxvmuriatic acid gas, I employed five grains
of roil sulphur, and admitted the gas into the exhausted
retort, from a vessel in which it had been in contact with
warm water: in this case more than a half a cubical inch
of oxvgen gas, and nearly two cubical inches of muriatic
acid gas, were produced. Suspecting in this instance, that
aqueous vapour had been decomposed, I employed cold
water in the next experiment, and dried the gas by muriate
of lime: in this case, though Sicilian sulphur was used, no
oxygen gas was evolved -} and not a half a cubical inch of

muriatic

Reflections on some Mineralogical Systems, 413

muriatic acid; the quantity was the same as in the last expe-
riment ; and it was found, that between \G and 17 cubical
inches of oxymuriatic acid gas disappeared ; the whole of the
sulphur was sublimed in the gas5 and the liquor formed was
of a tawny orange colour.

No oxygen was expelled during the combustion of phos-
phorus in oxymuriatic acid gas, nor could I ascertain that
any muriatic acid had been formed; three grain? of phos-
phorus were entirely converted into sublimate, by the ab-
sorption of about 23 cubical inches and a half of the ga9.

It would seem from these quantities, that the sulphu-
retted liquor formed by subliming suiphur in oxymuriatic
acid gas, consists of one proportion of sulphur, represented
by 13*5, and one of oxymuriatic gas represented by 329,
and that ihe phosphoric sublimate must be composed of
three portions of oxymuriatic gas, represented by 98'7 and
one of phosphorus represented by 16'5.

LXXVT. Reflections on some Miner ah a real Systems. By
JR. Chenkvix, Esq* F.R.S. and M.R.LA.^ &c. Trans-
lated entire from the French, with Notes by the Trans-
lator.

[Continued from p. 391.]

JL here is not a shepherd among those whose eyes and
mind have never exiended beyond the flocks which they
keep, the plains which nourish them, and the day which
affords them light, who could not convince the mineralogist
of the absurdity, should the latter wish to teach him that
a flock of wethers and ewes was a flock of animals of a new
species; and if the miner could perceive the mineralogical
individual, as the shepherd sees his wethers and ewes, the
doctrine of passages would excite laughter from Siberia to
Peru. It is below any other criticism*.

Finally,

* This is too severe; since M. Werner, not content to imitate Button in
world-makiag and forming the habitable giobe of a ball of glass invokes the
•hade of Moses, and furnishes us with " transition rocks, which are supposed
to have been deposited during the tmssoge or transition of the earth fi
chaotic to its habitable state " This knowledge, doubtless, is se perfectly
within the sphere of our senses, that we must congratulate the champions of
alt-nails on their singular modesty and consistency. " Hence," continues the
passenger or transitionist, ** they contain the first traces of organic remains
and mechanical depositions, and are denominated transitiQh rocks. They
are also highly important, as connecting the primitive with the fioetz rocks,
and thus preserving the beautiful wits of transitions which are to be traced
itom the oldest primitive to the newest alluvia! formations." Utahappiiy

tluoc

414 Reflections on some Miner alogical Systems,

Finally, the physical molecule is considered as without
parts : it tan only change ail at once ; therefore in the system
of integral molecule, the-re can be no intermediate or demi-
species of passage. In the system of" external characters,
passages are conceived, and all may he passages, if' it is
wished, for it cannot he said why any being is a species.

in geology things are somewhat different. Granite is
composed of' quartz, mica, and feldspar. By withdrawing
the influence of mica, if the quantity of" feldspar begins to
diminish in the granite, the latter will change its appearance
until that by continual variation it becomes gneiss ; and ul-
timate'y, when there will be no more feldspar, we shall have
micaceous schist. This micaceous schist may lose its quartz
or its mica, until it becomes on the one side mica and the
other pure quartz. We can therefore suppose all these mi-
nerals proceeding from granite, as a common centre, to
pure quartz, feldspar and mica, by three or more divergen-
cies like passages. But for what ? It is that in them all,
we have only the limits which are rigorous or definite,

In this pretended chain, with the aid of which theorists
have so often sought to bind all parts of the universe, we
see breaks at every step, and, far irom possessing the whole,
we have yet scarcely a few links. It was wished to force
them to unite, but the feeble clasps that men have substi-
tuted break in defiance of them.

A celebrated analyst has applied this word passage to a
remarkable error. In making experiments on a new sub-
stance, he observed that it changed colour under circum-
stances which produced the same effect on metallic oxides,
while that its other properties tended to those of the earths.
Hence he concluded that it constituted the passage or trans-
ition from earths to metals.

I have sucn in Germany, in a beautiful cabinet of petrifi-
cations, the head of a bear perfectly preserved and petrified.

these lovely transition rocks, like all other beautiful things are not numerous,
and Mr. Jameson knows only," 1st, transition-limestone ; '2d, transition-
trap; :ki, grey-wacke ; and 4th, flinty slate." He adds, in the true style of
German logic, p. 145, of what he calls " Elements of Geognosy,"' that
*' transition •limestone', which appears to be the oldest member of the transi*

•■>■;, is a simple rock !" The idea of transition and of tiinpHcrty is v/on-
deituily philosophical and congruous, ft wiii prepare the mind of the che-
mist foJ , namely, that this simple rock contains petrifications
of mar, . sa coraliiies, encrinites, trochites, &c, and that it is " very
frequently traversed by small veins of calcspar ; it is not particularly metal-

;," but that " we possess very little satisfactory information respect-
ing either the kind, repository, or quantity of ore it contains;" yet the au-
thor hesitates not to declare that it Is both a simple and a ironsiiion (i. e. com-
pouodj rock! — TlAffff.

I in-

Reflections on some Miner ah gical Systems. 4 1 5

T inquired if it was the common or the white Polar bear
[Ursus maritimus], and was answered, " It may be the
passage from one to the other." (Es mag wold ein ulergang
scyn.) The mineral kingdom, in appropriating this unfor-
tunate bear, has rendered it the subject of an absurdity.

With the word passage we may associate two other fa-
vourites in the same class; modification and tendence*. For-
merly manganese was considered as a modification of iron;
nickel, cobalt, lime, magnesia, the earths and alkalis, al-
most all were modifications. It might have been said that
in modifying nature produced all. When a man is afraid
of saying he does not know, he speaks of modification. But
philosophy, in appropriating to itself the sciences, has ba-
nished this fear ; and, in fact, what are all these pretended
modifications, but modifications of our ignorance ?

In the same cabinet of petrifications I saw a disciple of
the transcendent philosophy who admired each specimen,
was enraptured with a lichen, and in ecstasv before a fish.
" You believe/' said he, " that these are real impressions of
animals and plants. No; they are tendencies in nature to
form them ; tendencies to organization, — trials." Con-
ducting him gently near a beautiful piece of Florence marble,
<( Behold," said f, " a tendency in nature to build ruins."
I also demonstrated to him, by graphical granite, that nature
had a tendency to write !

The philosopher supported his opinions on the circum-
stance that among the petrifications we find natural species
which no longer exist : now, it is contrary to the svstem of
dualism that a species should be extinguished, as then the
sum of all the quantities in the universe would be no longer
equal to zero. I observed to him that these species might
be concealed for the moment in caverns. Yet he occupies
a distinguished place in the mines of Germany, and will
soon appear before the world in the character of an author.
How little honourable are these dreams, of which transcend-
entalism is so proud, even to human weakness !

SYSTEMATIC PRINCIPLES OF CLASSIFICATION.

Besides the division into species, five or six other general
ones are admitted in mineralogy (Kmmerling, p. 27, vol. i.
2d edition ; and Brochant, vol. i, p. 45), classes, genera,
subspepies, 8cc. There are, it is said, as many classes as
fundamental principles, («rund lestandtheile) marking, and
predominating in, the combination of minerals ; the earths,

* To these maybe added Mr. Jameson's English terms of Jijctz, suite,
foimatiuii. suiie, drusy, &c. fijfc* — Trans.

salts,

4 1 6 Reflections on some iJincralogical Systems.

salts, combustible minerals and metals. There are as man J
genera as chemical principles (clwmische bcstomdlheile) pre-
dominating in, or at least characterizing, the fossil combi-
nations. I know not what difference it is wished to make
between fundamental and chemical principles, and the
shades which separate them are not explained in a satisfac-
tory manner* Consequently I understand nothing of this
partition, in classes, genera^ 8cc. In the system of M. Hauy
there are four classes analogous to those of M. Werner ;
acicliferous substances, terreous substances, immetaliic com-
bustible substances, and metallic substances. In the first
class the alkaline and earthy nature constitutes the orders,-
and each individual base forms a genus. In the second
class here are no other snbdi visions than the species. The
third class contains two orders, the simple and compound
combustible^. Theifourth, three orders, according to the
voidability and reductabiiity of the metals, and each indivi-
dual metal forms a genus. All this is clear and precise, and
is not obscured by any superfluous explanations.

XI. Werner has divided the chemical elements into two
functions in the classification of minerals. They are either
predominant in (juantitv or characterizing. In coppery py-
rites, iron is the most abundant principle; yet copper gives*
the character to the mineral. Chemistry accounts for the
abundance of a principle : yet the particular characters of a
fossil, its orvctognostic and other properties decide on its
characterizing power. But as all is drawn from the testi-
mony of our senses, and every thing is made to speak to
them in this system, the minerals in such a classification are
transported to the place which the characterizing principle
may assign them, however contradictory it should be to the
abundant principle. Thus 0M5 of silica prevails over 0*76
of alumine, and places spinelie in the siliceous genus, while
()•£(> alumine against 046 silica transports the schist to the
argillaceous genus, and gives It its name. They have endea-
voured to explain the difference between the abundant prin-
ciple and the characterizing principle, by means of an en-
veloping matter {umbuUendcs sloffes) and the attempt has
had t lie success of most others for explaining that which we
do not understand ; it lias confined the difficulty to one
word. I shall not examine if this principle has been ob-
served in the distribution of minerals in genera, because-
this part of the classification is of little importance in com-
parison with that which treats of the species. It must how-
ever he observed, that it appears more and more every day
that we have gratuitously attributed to some elements the

idea

Reflections on some Mlneralogical Systems* 4 1 7

idea of certain exclusive properties. Silica is not the only
substance which in its aggregation can acquire extreme hard-
ness ; there are other earths which can become harder than
it : an aggregate of alumine surpasses it in thi* respect, as
we see in sapphire. And what shall we say of the dia-
mond ? Most assuredly we shall not consider it, like a cele-
brated German who said to me, when I made some ob-
jections to him on the place which he assigned (his fossil
and the new discoveries respecting it ; ie And who will tell
me that carbon is not also an earth ?"

DIAGNOSTIC OR DESCRIPTIVE MINERALOGY

We shall now proceed to the second part of mineralogy;
to the means which assist us in the diagnosis or art of know-
ing minerals. This will comprehend the art of making
them known to others, or that of describing them.

M. Werner has divided the diagnostic characters into,
1st, external characters ; 2(1, chemical or internal characters;
3d, physical characters; and, 4th, empirical characters.
Perhaps it may surprise some to see the latter epithet thus
confined to only a part of this system.

The preference given by M. Werner to external charac-
ters is manifest from what follows : (Brochant, Introduc-
tion, p. 30.) He examines these characters corresponding
to the five following questions : " What are the characters
which always manifest themselves, and in all minerals?
These are the external characters and the chemical charac-
ters, although thesmallness of the specimens often prevents
the latter from being discovered. (Is there not here a little
contradiction in the characters which always manifest them-
selves, and that often cannot be discovered ?)— What are
those which most certainly indicate an essential difference ?
The chemical characters; nevertheless, the external charac-
ters equally indicate the state of aggregation — What are
those which we can determine more exactly ? The external
characters, because the others require delicate operations. —
What are the most easily and most promptly found ? The
external characters, because they immediately strike our
senses. — What arc those which we can discover without
destroving the mineral ? The exterrial characters."

M. Werner principally employs but two chemical cha-
racters; fusibility bythe blow-pipe, and the proof of acids.
The physical properties which he mentions are electricity,
magnetism and phosphorescence, with their modifications; ^
and even the indication of these characters has no other ob-
ject but to complete the description of the minerals. In the

Vol. 30. No. 1S2. Dec. 1810. 2 D art

418 Reflections on some Mwefaidgicat SystcrM*

art of merely and simply recognising them, the principal re-
sources must be drawn from the external characters. Wer-
ner engages his pupils to use them to the almost total ex-
clusion of any other succour. They are enjoined to confine
themselves as much as possible to the limits of their senses;
the use of the microscope is prohibited, and the world which
exists beyond their organs must not be viewed by them.
They must not employ a drop of acid, to determine whether
a body effervesces with it, till the last extremity*. The
strong light of the sun, used to discover sparkling, ought to
be considered but as a microscopic mean which is not al-
ways in our power, Almost every thing that nature or art
offers to facilitate our researches is denied, and we are re-
duced to the simple light of the day and our five senses.

M. Hauy, after having founded the specification on the
form and composition of the integral molecule, adduces
means of attaining the diagnosis more easy and more
prompt thai, the inquiry into that form or composition. It
is true, he takes litile pains to describe ; and he does well,
because he can define ; but besides the character taken from
the integral molecule, he adds others with which physics and
chemistry have furnished him. Thus, for borated magnesia
we have as a ^eonielric character the cube; but this figure is
a term or limit, and consequently is common to other mine-
rals. Physical characters are therefore added ; as specific
gravity, hardness, elasticity, and a chemical character drawn
from the appearances w hen exposed to the action of the
blow- pipe. All the more striking characters are given to-
gether, which tend directly and absolutely to separate the
substances with which they might be confounded in conse-
quence of*the identity of form in the integral molecule.
This method, indeed, requires some physical and chemical
knowledge, while that of Werner dispenses with it sur-
prisingly.

WERNERIAN ESTIMATE OF SPECIFIC GRAVITY AND OP
ANGLES.

In (he particular exposition given by Werner of the ex-
ternal characters, he treats in the first place of colour. This
made many persons believe that he considered it as a principal
character, and drew on him reproaches from which I hasten

* Hence, doubtless, the reason that the disciples of Werner are all so furi-
ously hostile to chemistry, that they are so limited in their pursuits, so con-
tracced in their notions, and so deficient in those principles of general science
which contribute to meliorate the state of human existence, and improve so-
ciety.— Trans.

to

Reflections on some Mlneralogical Systems, s 410

to exculpate him*. Among the metals, indeed, he considers
it as of great weight, and in this he is supported by chemistry.
It is because the colour attracts the sight, that sense which
first informs us of the presence or* objects in general, that it
occupies the first place. The other universal external cha-
racters are cohesion^ unctuOsity, coldness, gravity, smell,
and taste. They are called universal, because they belong
to all minerals. It must be confessed, however, that among
them there are some which are of very little importance, and
merit slight attention. But specific gravity is not of this
number, and it will not be uninteresting to see the manner
in which it is treated.

A good hydrostatic balance or an areometer is all that if
necessary to take the specific gravity of a body, and the
operation is one of the most easy. Only a little patience*
Jess knowledge, and no reasoning are necessary to succeed.
But Werner banishes all exact modes, and says in general,
that a body swims on water ; that it is light when, water
being I,o00, it does nojt weigh 2,000 ; moderately heavy, if
from 2,000 to 4,000 ; heavy, from 4,000 to 6,000*; and very
heavy, if above 6,000. All that we can say from these for*

* This is candid and liberal, becoming a man of science i But how does
Werner's pupil estimate this character ? " In giving (says Mr. Jam. vol. i.) an
account of the crystallization of a mineral, we meniion its fundamental figure
or figures, describe their varieties, and arrange them according to their na*
tural alliances. Colour, which is a very important character, must also be
treated in a similar manner: the species and varieties must be correctly de-
termined, and arranged according to their affinities with each other? other-
wise, particularly in minerals possessing extensive suites of colour, as diamond
and sapphire, it would be very difficult to recollect them, and when remem-
bered would not convey to the mind a very distinct picture of this highly z'/j-
ferestiiig character. (Here the truth has transpired involuntarily.) I have
therefore been careful in the descriptions to determine the colours with pre-
cision, and to arrange them as much as possible in a natural order. In the
treatise of Haiiy, the colours are not arranged, and very seldom accurately
determined : this is the case, although not in so great a degree, with a more
useful work, The Miner;- logy of Brochant.'' It is true, the colours are not
arranged by Haiiy; as he, like a man of real science, treats them as purely
accidental characters. But what is the intrinsic value of the arranged
" suites of colours ? " There are perhaps no two persons living who have
identically the same ideas of colours, still less can any two equally find
■terms to describe their own notions of the matter. It follows then that each
individual will have his peculiar H suite of colours," arid that this " suite"
must be ranked with the " mineralogical instinct" of the Wernerians. I
have seen a German, a French, an Italian, a Spanish, a Portuguese, and an
English* mineralogist make the experiment together; each described sepa-
rately his own ideas of the colour of a Certain mineral in his native and in
all the other languages i the descriptions were then compared, first with
respect to the individual and nation, and next with respect to the six lan-
guages; and the disparity was such as would make any delicate mind feel
ashamed of the system built on such a sandy and indefinite basis. Yet Wer-
ner has not hesiuted to give his idea of the colour of a mineral as a name to
k U— Trans.

2 D 2 mulae

420 Reflections on some Mineralogical Systems.

mul® is, that mineral substances in general are moderated
heavy, since that of 233 minerals, whose specific gravity is
given by Haiiv (vol. i. p. 261), there are 133 between 3,000
and 4,000, and only 46 which are between 4,000 and 6,000.
By describing a mineral thus, native sulphur, whose specific
gravity is 2*0332, and telesia, which weighs 3*9941, would
be included in the same expression.

The estimation of the angles is given with a precision
worthy of that which characterizes the estimate of the spe-
cific gravity. An angle is very obtuse when it is greater
than 120°; obtuse, if it is from 100° to 120° ; a little obtuse,
from 90° to 100°; right, if it exceed 90°; very acute, be-
tween 45° and oo° ; acute, when it is 45° • and very acute,
when it is less than 45°. (Brochant, vol. i. p. 97.) Thus
we learn that a right angle is that which has more than 90°.
I have heard M. Werner say, (and I have written his lectures
as he delivered them,) that a difference of 10° did not pre-
vent him from considering any angle as a right angle : thus
we need not be much astonished at seeing cubic zeolite so
called [analcime and chabasia, H.], as the great angle of its
faces differs but 3° 30' from the right angle.

WERNERIAN THEORY OF PRIMITIVE FORMS.

Crystallization is treated as a third article in the particular
external characters of solid minerals, under the name of
regular external forms. It is observed that there are seven
species of principal forms, which may be considered as the
nuclei of other forms; and in this point of view they fulfil
the same functions as the primitive forms of Haiiy.

Werner was at perfect liberty in his choice, as he set out
on a gratuitous hypothesis. There was no consideration
which impelled him to give a preference to such or such a
form. He had before him the whole of geometry, with the
unlimited permission of choice among all the figures which
it possesses in common with mineralogy. We must be-
lieve that some principle adopted by reflection would preside
at the choice he was about to make, and we can conceive
none more worthy of preference than that which corre-
sponds with simplicity.

M. Werner has chosen the icosaedron, or body terminated
by twenty faces; the dodecaedron, by twelve ; the cube, by
six ; the prism, pyramid, table, by an indeterminate number ;
and the lentil, or lens, by two, as it is pretended. The
icosaedron is a very complex figure; the prism, pyramid,
and table, are in some measure indefinite ; and the lentil,
which we are told is composed of two faces, is; indeed/com-
posed

Reflections on some Miner alogical Systems. 421

posed of two bent faces, but they result from an infinite
number of planes. The character of simplicity therefore is
totally wanting in this choice.

Still, however, there are many more objections to this me-
thod. There is scarcely any figure which I have not heard
considered in several points of view. The dodecaedron with
rhomboidal faces has been sometimes regarded asahexaedral
prism, terminated at each extremity by a triedral pyramid.

The hexaedron appears entirely useless, as besides this
figure there may be two modes of considering all the cry-
stals which belong to it. The cube, for instance, is a hexae-
dron, but at the same time it is a quadrangular prism with
square faces. The rhomboid is also a hexaedron and a
quadrangular prism, with rhomboidal faces; and every te-
traedral prism terminated by planes as bases is a hexaedron.
Moreover, these figures may be considered as two mutilated
triedral pyramids, united, it is true, base to base, with the
edge against the face. Here then is a crystal which belongs
to three different species of principal forms ; and such is the
influence of this character in the specification of minerals,
that the same mineral may very weli belong to three species
in the oryctognostic system.

The table is nothing but a prism extremely shortened.
The geometer knows as well as any other what a table is :
but 1 suspect that from Archimedes to Newton ; from the
first who failed in squaring the circle, till the learned Ger-
man who told me that he had discovered a fourth dimension
in space,^— no geometer has treated it as a geometrical figure.
This invention is purely mineralogical. But where does
the prism finish, and the table commence ? Is there a point
where a crystal being no longer a prism is not yet a table ? I
do not see why the table should not be ranked among the
imitativeiforms, as the club, bush, comb, mirror, and other
usual instruments.

WERNERIAX PRETENSIONS TO THE DISCOVERY OF THE
INTEGRAL MOLECULE.

There is an article in the external characters of Werner,
which at first seems to have some resemblance to the form
of Haiiy's integral molecule : I mean what relates to the
lamellated fraciure. After having spoken of the perfection,
imperfection, ike. of the lamince, their direction and their
form, he speaks of the structure of the laminae (lamina-
tion), or of the cleavage (durchga?ig der blatier), and says
that it may be double, triple, quadruple, and sextuple. If
it were wished to enter into all the details of this subject,

2 D 3 we

422 Reflections on some Mineralogical System*.

we could find nothing more proper to demonstrate the weak-,
ness and futility of the system of external characters ; but
it is not, in fact, worthy of attention. Let us take only two
instances. Mica is given as a mineral which has only a
single direction of cleavage; this supposes two faces termi-
nated by planes. But two planes are not sufficient to con-
tain a solid. What then terminates the other faces of mica?
This is what Hauy found in discovering other directions of the
laminae, by which he was led to determine the primitive form
and integral molecule of mica, which is a right quadrangu-
lar prism whose bases are rhombs. Consequently there are
three directions of the cleavage, and each of these three has
another parallel to it, whence result six parallel faces two
and two, or a parallelopiped. According to Werner, hya-
cinth has but two directions of cleavage. Haiiy found its
primitive form an octaedron with isoscele triangles, and con-
sequently its integral molecule a regular tetraedron, and four
directions of cleavage. Werner stopped his researches
where his senses abandoned him. Hauy has availed him-
self of all the means which a profound knowledge of the
different branches of the natural sciences has put in his.
power ; and in throwing a strong light on certain minerals,
he has rendered sensible the fissures which could not other-
wise- have been perceived.

Some persons, indeed, have pretended to infer from what
Werner says respecting the property of cleavage, that he
also knew the form of the integral molecule, but having
perceived its futility as a principle of classification, he
abandoned the idea. Two notes (p. 28 and 127 of the
French translation), in his Treatise on External Characters,
nave been pointed out as announcing clearly his opinion.
I have been able to see nothing in the first, except that ani-.
mals and vegetables have different parts, which we call or-
gans, and that the separation of those parts destroys the
animal or vegetable, while we can divide a mineraj into as
many small parcels lis we please, without its ceasing to be the
same mineral. But jf we destroy its composition, then the
mineral is destroyed. Tt is not therefore doubtful that their
relations consist in their composition. In p. 31, there is the
following remarkable but just observation : " The systems
oft hose who have wished to arrange fossils by their external
characters* have already furnished a proof of the inconve-
nience

* I have been assured by an old pupil and relative of Werner, that it wai
not originally his intention to form any system of mineralogy on external

characters^

'Reflections on some Minerahgical Systems. 423

nience of this method, as we there see fossils essentially
different plaeed together, while those of the same species
are dispersed in consequence of some accidental variety."
In a note, p. 127, he speaks or " aggregated parts, or of
those which we can obtain by mechanical division, and of
those whose union forms the preceding, or of simple parts
which are not divisible without changing their nature. As
to those which compose the simple parts, and which, in fact,
are themselves compounds (I cite the words of the author),
they take the name of constituent parts. I shall, however,
call primitive constituent parts those which form the con-
stituents, and which are neither compounds nor aggregates,
but absolutely simple parts or the first elements of matter.'*
It appears to me that there is nothing in all that I have
quoted, which has any reference to the form of the inte-
gral molecule. It is there said that bodies have molecules
and elements; and we also learn something new, such as
simple part which are compounded, and compounds of com-
posed parts ; but there is not a word of integral molecule.

To me, indeed, it appears rather censuring than excusing
M. Werner, to say that the discovery of the integral mole-
cule is due to this philosopher. If he had perceived its ex-
istence, why has he abandoned it ? why did he leave a field
so fertile in brilliant discoveries to be cultivated by any
other than himself? But these questions are superfluous,
as we have seen that the learned mineralogist (or, if he will,
oryctognost) of Frevberg had no knowledge of the integral
molecule before M, Haiiy. Judging, indeed, from the ob-
servations which I have heard him make more recently on
this subject, it does not appear that he has yet sufficiently
studied the matter to comprehend it perfectly even at the
present day.

[To be continued.]

characters, but merely to digest, arrange, ormethodize those characters, so that
various chemists migkt easily discover .whether it was identically the same
piineral which they analysed, and that they might have less trouble and be
more accurate in their descriptions of the subjects cither produced or ope-
rated on. In his preface, indeed, he observes explicitly, " It will be seen
that I have taken care that no one should make ut>t of these external characters
1» rsfjikl.tsh a si/s!r»iatic division of minerals, as has been hitherto done ; but
solely to determine the idea of their exterior appearance, and fix the method
of descrii'iufr them." Had he still adhered to this judicious and necessary
plan, he would have contributed very materially to facilitate the progress
of mineralogicai science; but the vanitv of making worlds, forming mo\m-
tains, transitions, primitive rocks, and finally deciding on the effects of water
and the construction of the whole crust of the earth, has propagated the
propensity for *' those wonstr<inties known under the name of theories of the
(P'h" which flarrer the imagination, but retard the progress of reason and
rue science. — 1 ran a.

2 D 4 LXXVII. Me-

[ 424 ]

LXXVII. Memoir on the Diminution of the Olliquity of the.
Ecliptic, as resulting from ancient Observations. By
M. Laplace. Translated from the " Connoissance
des Terns for 181 1" &y Thomas Firminger, Esq.

To Mr. TillocL

Sir, J. he variation of the obliquity of the ecliptic having
been a phenomenon in astronomy of a nature to engage the
most lively interest of those who have made this sublime
and useful science the subject of their study, and as its in-
vestigation has never been fully developed till the appearance
of that profound work the Mecanique Celeste of M. Laplace,
I have no doubt the following comparison of ancient ob-
servations with the deductions derived from his formula
will be highly interesting to many of your readers. The
article is taken from the Connoissance des Terns for the year
1811; and the only apology offered for its translation is
the extreme scarcity of that work in this country : it was
drawn up by the profound mathematician and philosopher
above mentioned, with a view to compare his deductions
with the actual state of the system at an interval of time as
great as observations of sufficient accuracy would admit;
and the coincidence, taking into consideration the imperfect
state of science in those ages, is remarkably striking. It
pres'ents to us not only one of the most undeniable proofs
of the Newtonian principle of gravitation, a fabric on which
the whole of the Mecanique Celeste is founded, but furnishes
the historian with facts which give additional credit to the
faithfulness of the narration. On this as well as on other
occasions we have a right to form our opinion from analogy.
We see the recorded observations agree, as nearly as the state
of science in those days will admit, with what theory has
assigned to them; and as they do not make a separate his-
tory of themselves, but are coupled with the history of
the times in which they were made, the known truth of the
one gives a satisfaction to the mind in appreciating the value
to be affixed to the other. If we look to the account given
in the Lunar Tables published by the Board of Longitude
in France, we shall find those tables were compiled princi-
pally from the astronomical observations made in the Royal
Observatory at Greenwich ; and not only the epocha, but the
present state of diminution in the obliquity of the ecliptic
has been in a great measure determined from them: we
shall not, therefore, be surprised to fiud, hereafter, a nearer

coin-

Diminution of the OHiqitiiy of the Ecliptic. 425

coincidence in the actual state of the ancient observations,
and the deductions drawn from theory, when we possess, as
we hope soon to do, the means of settling this epoeha and
actual state of diminution at the present period. The grand
mural circle now making for the Royal Observatory, by
Mr. Troughlon, will, it is expected, be in readiness for ob-
servation early in the ensuing year; and we cannot doubt
but that the first object to be determined with it, will be
the settling of the above-mentioned data, so essential in the
theory and practice of astronomy. TLe observations of
Mr. Pond have clearly tended to show errors in the mural
quadrants at Greenwich of considerable magnitude ; and
whatever accuracy these instruments might originally possess,
we have now no hesitation, from a comparison of contem-
porary observations, not only of Mr. Pond, but of Mr.
Groombridge, Dr. Brinklv, &c, to express our satisfaction
on this point. Indeed it is not difficult to account for the
above-mentioned errors, when we take into consideration
the construction of the mural quadrants, and of the obser-
vatory in which they are contained. These instruments are
freely suspended, in a line nearly with their centre of gra-
vity, by two pins from a large stone pier; the upper and
'lower parts are therefore very differently affected by every
change of temperature in the atmosphere: for instance, if
we suppose an increase of heat to be equally diffused over
the whole instrument; the upper part (for "we must consi-
der the expansion as taking place from the point of suspen-
sion) will be less affected than the lower, it. having the ac-
tion of gravity counteracting the force of expansion, whilst
the lower part is assisted in its expansion from the same
force of gravity, and vice versa ; or, in other words_, with its
own weight, which in these instruments is very great, the
whole I think amounting to nearly 1000 pounds each. We
shall therefore observe, that it is scarcely possible for these
instruments to have retained their original accuracy for but
a very short space of time after they were first put up : the
change however might be inperceptible for several years ;
but as we now know that metals when continually acted
upon, do not retain their first figure except where the parts
arc duly balanced, we can easilvsee how the change of figure
must necessarily happen. In running our eye over the ob-
servations made by Dr. Bradley with Bird's mural quadrant,
we find frequent mention, when observing the stars in the
night-time, and particularly when the difference in the tem-
perature of the atmosphere within and without was very con-
siderable,

420 Memoir on the Diminution of the

siderahle, that it was necessary to lower the quadrant a little ;
and it was a practice always to keep the plumb-line constantly
over the point at bottom, without any regard to the variable
temperature of the instrument. Admitting, therefore, the in-
strument at the commencement of observation to have had an
equable temperature and to have been nicely adjusted; it is
evident that a readjustment, after a partial effect has taken
place, is to throw so much error into the observation. I have
often been surprised that so sagacious a man as Dr. Bradley
should not have noticed this circumstance. It accounts* in
the most satisfactory manner for, the disagreement in the
deductions of the observation of the stars in the feet of Ge-
mini, used in carrying forward the error of collimation de-
duced from comparative observations with the zenith sector
and quadrant. The variations in these instruments are
likewise rendered still greater from the construct ion of the
Observatory, which, having a slanting roof, receives the
Fun's rays almost perpendicularly upon it, and is so much
heated in summer as to occasion a change of temperature
in the top and bottom of the room amounting to 10° or
1-2°. Such a roof is perhaps capable of many facilities in
the opening and shutting the necessary shutters, but I think
it is the very worst form for an observatory. The adoption
of circular instruments in the &tead of quadrants is one of
the greatest improvements in practical astronomy. In the
instrument now making by Mr. Trough ton, any part may
be made the depending one, and the whole instrument be-
ing constantly turned about must preserve its proper figure.
The article which I have herewith sent you, sir, being a
very long one, I will not trespass further at present, intend-
ing at some future period to take an extensive view of the
progress and im proved state of practical astronomy*
Your very obliged

and obedient humble servant,

Thomas Firmingkr.

Although the successive diminution of the obliquity of

the ecliptic, as we approach to modem times, cannot now
be controverted, still it is with the greatest interest that
we witness at the end of ages the slow development of
the great inequalities of the system of the world. In
aiter ages, when with the results of theory a long series of
very accurate observations can be compared, this sublime
spectacle can be enjoyed much better than it is by us, to
whom antiquity has only transmitted such observations a,s

oftea*«

Obliquity of tin Ecliptic, 42f

oftentimes are doubtful. But even those observations, when
submitted to sound criticism, may, owing to the distance
of time when they were made, throw great light on several
important elements of astronomy, and therefore deserve all
the attention of geometers and astronomers.

OF OBSERVATIONS ANTERIOR TO OUR ^ERA.

Chinese Observations,

The Chinese observations I am going to relate, are ex-
traded from the " Edifying Letters on the History of Chinese
Astronomy by the learned Father Gaubil," published bv
Father Sauchet, and particularly from a precious manuscript
sent from China by the said Father Gaubil in 1/34, which
I have published in the Conn, des Terns of 1SOQ.

The most ancient observation that has reached us, relative
to the ecliptic's obli<]uitv, is Tcheou-Kong's, the brother of
Vou-vang emperor or China, who, towards the year 1 loo
previous to our sera, had occupied himself with particular
care in making astronomical observations. After his bro-
ther's death, he was regent of the empire, and his memory
is still in great veneration among the Chinese, as having
been one of the best princes that ever governed. His ob-
servations on the length of the gnomon at the solstices are
the most ancient astronomical observations that can be used,
All anterior observations of eclipses and solstices that have
reached us, are related in too vague a way to serve for astro-
nomical determinations ; they are of service only to en-
lighten chronology ; and if other observations are wanted
that can be truly useful to astronomy, we must go back
from the epocha of Tcheou-Kong to the time when the
lunar eclipse was observed at Rabylon, the year 720 previous
to our sera, as related in the Almagestes of Ptolomy. This
great antiquity of Tcheou- Kong's observations, and their
vast importance, induce me to expect that the details I am
about to enter into respecting them will be perused with
interest. Here, first of all, is what Father Gaubil records in
his History of the Ancient Astronomy of the Chinese, in-
serted in the xxvith vol. of.*4 Edifying Letters," p. 142.

^Tcheou-Kong, as well as his father prince Ou-en-ouang,
and one of his ancestors, prince Kong-hicon, of whom men-
tion has been made, took a delight in observing the shadea
of gnomons. In the town of Tching-tcheou he drew with
care a meridian line, he levelled the ground for observation,
he measured the shadow at noon and afternoon; at night he
pbser\;ed the pol.ar star. This prince also caused observa-
tions

42S Metnoir on the 'Diminution of I he

lions to be made in places westward, eastward, northward,
and southward, of Tching-teheou.

"In the town of Tching-teheou, a gnomon eight feet
long gave at noon, at the summer solstice, a shadow of one
foot live inches. The declination of the sun being sup-
posed 23° 2o/> the observation of Tcheou-Kong gives the
north latitude 34° 22' 3". 'Hie centre of the town Hon-an-
fou has been observed at a latitude of 34° 43' 15", with an
instrument made by Chapontot, by several altitudes of the
?un : — difference between the missionaries' observations and
Tcheou-Kong, 21' 10', of which quantity Hon-an-fou
would appear to be more to the northward than given by
Tcheou-Kong's observation. Although the exact situation
of the town of Tching-teheou cannot be ascertained, it
appears that the difference from Hon-an-fou cannot give
a di (Terence of 21' 10". A want of accuracy in the observa-
tions, particularly in the gnomon, might produce a part of
this difference.

" The missionaries supposed a declination in the ecliptic
of 23° 20/ : ihey applied refraction, parallaxes, and diame-
ter of the sun, agreeably to de la Hire's new Tables, and
thought they were sure of the adjustment of the instrument.
The difference may also arise from some change in the obli-
quity of the ecliptic."

I shall in the first place observe, that the Chinese divide
the. foot into ten inches, the inch into ten fen, the fen into
ten li, the li into ten Jiao, &c: so that thelength of the shadow-
is one foot five inches. As to the latitude of 34° 43' 15" of the
town of Tching-teheou, the same as has been designed by
the names of Loyang and Hon-an-fou, Father Gaubil, in a
note of the page just cited from " Edifying Letters," says
that that observation was made in June 1712 : that according
to one observation this latitude was found 34° 52' 8"; and
to a. second, 34° 46' 15"; lastly, that a third gave 34° 43'
15/' This last appears to him preferable to the other two.
The difference of these results proves the want of exactness
in those observations, which, combined with the incertitude
< i the exact place of Tcheou-Kong's observations, would
render it highly desirable to. know the length of the shadow
in the winter solstice, at the time of that prince.

This is what I find on this subjeei in the j\IS. cited by
Father Gaubil. [Conn, des Terns for I 809, p. 3Q3v)

" At all times the Chinese have observed the sun's
shadow at noon, and at other times; but the most ancient
observation we are possessed of is that of Tcheou-Kong,

brother

Obliquity of the EcUplk. 429

brother of Vou-vang, in the town of Loyang. According
o tradition, a gnomon of eight feet cast at noon a shadow
one foot five inches long at the summer solstice. This
shadow is mentioned in the ancient hook of Tcheou-li, and
in other books, and the authors of the Han consider the
observation as incontestable.

" Loyang is the town of Hon-an-fou in Hon-an. Ac-
cording to Father Regis's observation, this town is placed at
the latitude of 3<T i$ 15". Father Demaille observed, to-
gether with Father Regis, as well at Cai-fong-ion as at
Hang-tcheou.

" A shadow of one foot five inches from a gnomon eight
feet long, gives a latitude of near 34° 22', supposing the
declination of the ecliptic 23° 29/. Tcheou-Kong governed
the empire for his nephew in the year 1 100 before Christ;
and it was he' that caused the imperial palace to be built at
Loyang, which was a second court of Teheou's empire.
Therefore, if we were to admit a declination ofv2QJ 55' at
the time of the observation, the latitude would be 34*
48' 51"; which is remarkable.

6i It was again a tradition, that in fhe winter solstice
Tcheou-Kong observed with the same gnomon a shadow
of 13 feet. This tradition is not so certain as the. former.
This shadow would <rivc a true altitude for the sun's centre
of 3 1° 18' 42". The summer shadow gives 79° lf 1 1"; — dif-
ference 47° 48' 49"; half of which, 23° 54' 24" 80*', would
be the ecliptic's obliquity; which is worthy of remark. If
the calculation of the ) uitude was made from the shadow
at the winter solstice, supposing the declination 23° 2i/,
it would give a much more northerly latitude than what
the altitude in the summer solstice gives."

In vol. ii. p. 21, of his History of Chinese Astronomv,
published by Father Sauehet, Father Gaubil attributes the
same observation to the authors of the Astronomv of Sfefen
in the said town of Loyang. But in the manuscript I have
just quoted, he relates what follows, [Conn, des Terns JS09,
p. 394.)

The authors of Sfefcn's Treatise of Astronomv have, no-
ticed for Loyang at the two solstices, the shadows observed
by Tcheou-Kong, and recorded in the first observation.
These authors have given shadows for the other days of the
year in the equinoxes. These 'shadows are so faulty that
no dependance can be placed on the observations. The
authors no doubt considered Tcheou-Kong's observation
as unreformable.

" In several treatises of Chinese astronomy, the shadows-

in

430 Memoir on the Diminution of the

in the solsliccs at Loyang, attributed to Tcheou-Kong, arc
first «ct down ; after which rules are given to add to, or sub-
tract from, the length of these shadows, according as the
places are further north or south than Loyang, What I
here mention is clearly explained in some of the said works?
but in others, the editors have not been careful to give the
rules for the increase or decrease of the shadows observed
by Tcheou-Kong, for application to places iurther north or
south ; whence it arises that in calendars for Nanking or
Ilin-tcheou, or other towns, the shadows are ^given for
Loyang only."

From the foregoing, it appears to me that no doubt can
be entertained of the quoted observation not wholly belong-
ing to Tcheou-Kong. The learned Freret has calculated this
important observation in the third part of his excellent Dis-
sertation on the Certainty and Antiquity of the Chinese
Chronology. This is what he says:

" The most ancient observation of the solstices that is
known with certainty is prince Tcheou-Kong's, brother to
Vou-vang the founder of the dynasty Tcheou. Tcheou-
-Kong was regent of the empire from the year 1104 to the
year 1098. The observation was made in one of these six
years. The precise date of the observation for the time of
the cycle and moon is not marked, but the place of ob-
servation and length of shadows are known. This detail is
related in the Tcheou-li, which is a part of the Li-ki or
Book. of Kites.

"A gnomon was made use of, of eight feet Chinese: at the
summer solstice the shadow was one foot five-tenths, and
in the winter it was 13 feet ; which gives for the obliquity
of the ecliptic 23° 54' 14"; the same quantity nearly as was
supposed by the ancient Greek astronomers Pytheas, Era-
tosthenes, Hipparchus, and Ptolomy.

" The altitude of the pole at Loyang, (place of the obser-
vation) as determined by the altitude of the sun above the
horizon and by the resulting obliquity of the ecliptic, is
found 34° 4/' 33". Regis and Mailla, by an observation
made with accurate instruments, have found it 34° 46' 15".
By the obliquity of 23,29 as supposed by our modern astro-
nomers, Loyang would be placed at 34° 3-/, differing only
15' 13''; which gives room to presume that the obliquity of
the ecliptic must have changed.

" The observation of Tcheou-Kong was made at a time
anterior to Solomon's reign, and about the war of Troy. Its
exactness proves that observations must have been made in
China several centuries back."

Frerct's

Obliquity of the Ecliptic, . 431,

fVeret's calculations want a slight correction. By recti-
fying them, and allowing for the refraction and the parallax
of the sun supposed to be 8",7> J find 79° 22' 39,6 for
the altitude of the superior edge of the sun's disk at the
summer solstice, aud of 31° 35' 1",8 for thatof the said cA^a
in the winter solstice* By subtracting the apparent semi-
diameter of the sun at the two solstices, which I find to be
15' 47">7 and 16' 14'$3 respectively, the corresponding al-
titudes to the centre will be 79° 6' 5i",9, and 31° 18' 47",3,
which gives 23° 54' 2", 2 for the obliquity of the ecliptic,
and 34J 47' 10" for the polar altitude; which, being nearly
a mean between the three observations of the missionaries,
proves the accuracy of Tcheou-Kong's determinations.

Freret by certain and ingenious calculations had in the
same dissertation fixed theepochaofTcheou K^i^s regency
between the year 1098 and HOl, before our aera. 1 shall
observe that in this respect he agrees perfectly with Father
Gaubil. I shall then suppose that these observations were
made in the year 1 100 before our aera. I have given in the
3d vol. of my Mec. Cel. b. vi. ch. 12, a formula by which
the obliquity of the ecliptic may be determined for a very
distant period : and t expressing a number of years elapsed
since 1750, the value of this obliquity in decimal degrees
will be

26°,0706— 3676',6l— cos(^3",0446) — 10330,4 sin (tgg\ 1 227)
whereby t — — - 2850, which gives in decimal degrees the
corresponding obliquity of the ecliptic = 26 \5 "6il, or in
ordinary degrees =25° 51' 53' ; which must be increased
about 5', because the obliquity of the ecliptic in 1750 ex-
ceeded to that amount the quantity used in the preceding
formula: thus 1100 years before our sera, the obliquity of
the ecliptic was 23° 51' 58', — a result which only differs
2' 4" from that given by die observed lengths of the gno-
mon shadow in the two solstices. A more perfect coinci-
dence cannot be wished for, if allowance be made for the
uncertainty attending this sort of observation, owing parti-
cularly to the penumbra which renders the shadow ill-de-
fined.

If, together with Father Gaubil, the observation alone of
the summer solstice was taken into account, and the polar
altitude at Loyang was supposed with him to be 34° 43' 15",
by subtracting its complement 55° 16' 45" from the alti-
tude 79 3 6' 52" of the sun's centre, determined by the length
of the shadow in the summer solstice, the obliquity of
the ecliptic would be 232 50' f. The result of my for-
mula is very nearly a mean between that and the obliquity

given

432 Memoir oil the Diminution of the

given by the observed lengths of the shadow at the two
solstices. This coincidence is a remarkable confirmation
of the value of the masses of Venus and Mars, which M.
Delambre has determined by the comparison of a very great
number of observations of the sun by means of the formu-
las, and of the perturbations of the earth's motion I have
given in the 3d vol. of Mac. Cel.

Tcheou-Kong, by his observations, had determined the
moment of the winter solstice, but they have not been
transmitted to us. We only know that he fixed this solstice
at 2° Chinese from V, a constellation which begins at s of
Aquarius, (vol. xxvi. of Edifying Letters, p. 124.) We
shall also fix the epochas of this determination at 1000 years
before our sera. Tcheou-Kong and the Chinese astronomers
at that tkftft referred the constellation to the equator; be-
sides 2° Chinese = 1° 58' 17": subtracting this from 270°,
the difference 268° l' 43" was the right ascension of s of
Aquarius at the epocha of 1 100 years before our aera.

In the beginning of 1750, the longitude of s of Aquarius
was 308° 14' 10"; its latitude was north 8° 6' 20'.

Comparing Bradley and Mayer's catalogues with Piazzy's,
this star does not appear to have any sensible motion of
its own, and its annual precession is 50", 1.

I find by the formulas of c. xii. of book vi. of Mec. Cel,
for the epocha of 1100 years before our sera,
rj/ -J40" 2' 43"
V = 23° 32' 49",
jt being the precession of the equinoxes from that epocha
till 1750. This precession being referred to the equinox of
1 750, is the obliquity of ihe equator on this ecliptic at
the same epocha. Thus at this epocha the longitude of £
of Aquarius, computed from the intersection of the equator
with the. ecliptic of 1750, was in the year 3 100 before our
aera 268° J l' 27"; whence I conclude its right ascension,
relatively to the same intersection, to be equal to 268° 9' 2".

I aiterwards find, by the formulas of the quoted chapter,
• o" = 3.5' 44"; 9 = — 1° 33' 25" :
<p" being the ecliptic's inclination from that time, above
that of the ecliptic of 1750, and 9 being the longitude of
its node upon that said ecliptic, computed from the fixed
equinox of 1750. Whence I conclude that the right as-
cension of the true equinox with the preeeding; that is to
sav, the equator's intersection with the fixed ecliptic of 1750,
was in the year 1 100 before our sera equal to —-42' 12";
the right ascension of s, relative to the true equinox, was
therefore then 26Sa 51' 14", greater by 49' 31'' than Tcheou-

Kong's

Obliquity of the tlctipiic. 433

fcong's determination. This difference will appear very
small, when we consider the uncertainty of the precise
epocha of the observation on which this determination is
founded, and above all the uncertainty even of the -observa-
tions. It would suffice to remove 54 years beyond the UOOdth
before our aera> to reduce this difference to nothing, and
then the observation would belong to the time of Ou-en-
ouang, father of Tcheou-Kong, Whom Father Gaubil men-
tions as having much loved and cultivated astronomy. The
Chinese astronomers determined the moment of the solstice*
by observing equal lengths of the gnomons' shadows forty
or fifty days previous and after the solstice; and from
that there may already be some error inTcheou-Kong's de-
termination. But the greatest error that is to be appre-
hended in the observation is in the manner of referring the
solstice to the stars, in order to which the moment of the
passage of such stars as crossed the meridian twelve hours after
the moment of the solstice was observed: thus the right
ascension of the opposite point to the summer solstice
would be determined, and therefore also that of the win-
ter solstice. But for so doing it was necessary to measure
an interval of twelve hours. It appears that hour-vessels
were used for measuring the time that a vessel was in fill-
ing to different heights with the water falling from a higher
vessel (Treatise of Chinese Astronomy of Father Gaubil,
published by Father Sauchet, Part I. p. 37.) It is easy to
perceive how uncertain this manner of measuring time was,
and three minutes of time, in an interval of twelve hours,
are sufficient to account for the error of Tcheou-Kong's
determination. The Chinese astronomers made likewise
use of the moon's situation relatively to the star3 in the
lunar eclipses, to obtain the place of the sun, and therefore
that of the winter solstice, at which they fixed the com*
mencement of their year.

We must come down a thousand years, from Tcheou-
Kong's epocha, before we find a second observation of the
gnomons' shadows made in the solstices in China. Towards
the year 104 before our aera, the astronomers Lieou-hiang and
Lo-hia-hong observed the length of the shadow of an eight-
feet gnomon at the winter and summer solstices. They
found it 13 feet one inch four fen, or 13ft, 14 at the
former, and one foot Cive inches eight fen, or lft,58 at
the latter (vol. ii. of Chinese History, published by Father
Sauchet, p. 8). This observation is supposed to have been
made in the town of Siganfou, then the capital of the em-
pire : but this is an error which Father Gaubil has rectified

Vol. 36. No. 152. Dec. 1810. 2 E in

434 Diminution of the Obliquity of the Ecliptic*

in the quoted manuscript; in which is read as follows :(Comr,
des Terns, I8O9.)

" Lieou-hiano-, father of Lieou-hia, wrote upwards of 50
years before Chiist. This author says that an eight -feet
gnomon gave the noon shadow in the winter solstice 13
feet one inch four fen, in the summer's it was one foot
five inches four fen. Litchun-foung, an astronomer of
the dynasty of the Tangs, complains that these shades were
improperly applied to Siganfou. Lieou-hiang mentions
neither the place nor the time of these observations."

The shade at the summer solstice is not exactly the
same as that published in the quoted History of Chinese
Astronomy ; but I think that this last ought to be preferred,
the shadow given in the MS. giving an evidently too con-
siderable obliquity of ecliptic. It is very likely that in the
manuscript Father Gaubil may have written, in a mistake,
instead of eight fen the same number that he wrote for the
winter solstice. Adopting therefore, lft, 14 and 13ft, 58
for the lengths of the shadows at the summer and
winter solstices, and allowing for the refraction and the
sun's parallax, I find 31° 2' 23" and 78° 33' 4l" for the
altitudes of the sun's centre, resulting from these observa-
tions. Half of their difference gives 23° 45' 39" for the
ecliptic's obliquity. If we add it to the complement of 78*
33' 41", we shall have for the altitude of the pole 35° 11'
58", an altitude very different from that of Siganfou, which
the Jesuits have found 34° 16' 45''. Litchun-foung was
therefore right to complain that these noon shadows had
been improperly referred to Siganfou.

To compare my formula with this observation, I suppose
that t = — 1850, and then it gives for the obliquity of the
ecliptic 23° 43' 59" ,4, and by adding 5', as we have done
for the preceding observation, we shall have 23° 44' 4'', 4,
which only differs l' 34",6 from the result of this second
observation. These two observations are the only ones
before the commencement of our sera, that Father Gaubil
has made us acquainted with; and it is to be supposed that
this learned missionary could not discover others : the de-
struction of books by fire, which took place 213 vears pre-
vious to the Christian aera, having caused the loss of the
•greatest number of preceding observations.

[To be continued.]

LXXVHI. Re-

[ 435 ]

LXXVIH. Reply to Mr. M.'s Remarks on Mr. Smyth's
Comparative Table in vol. xxxv. p. 488. By Mr. Smyth,

To Mr. Tilloch.

Sir, JL shall esteem it a favour if you will insert the fol-
lowing answer to the gentleman who signs himself M. in
your Magazine for September.

Mr. M~ says it is " curious that Mr, S. should presume
organ-tuners will continue to tune as their ancestors did
before them, till irrefragable arguments are produced to
prove the superiority of Kiruberger's temperament." Here,
I confess, 1 stand convicted of inconclusive reasoning.
The fact, however, I imagine to be this: an organ, with
compound stops', will not admit of the major thirds being
tuned sufficiently sharp to ameliorate, in any considerable
degree, those greatly tempered chords which are called
wolves; of which I wish the breed were extinct.

I am glad to find that Mr. M. agrees with me in opinion,
thai Kirnberger's is one of the worst unequal temperaments.
Had Mr. M. stated in definite terms his own favourite sy-
stem, it should have been submitted to examination.

Mr. M. says, " perhaps for the organ a good unequal
temperament is preferable to the Isotonic." I was not ig-
norant that even for this instrument the Isotonic has had
its advocates; and Mr. M. presents to my view the names
of Couperin,Marpurg, Rameau, Cavallo, professor Chladni,
and many other eminent philosophers. Now, not being a
philosopher myself, I take the liberty of asking one plarn
question, which relates1 solely to the temperament of the
organ : — Can any man living prove, that there ever was one
organ in Christendom tuned according to the equal tem-
perament, in consequence of a peremptory order from any
one of these gentlemen, and suffered to remain in that state ?
This is coming to the point,

A person disposed to cavil might raise arithmetical and
philosophical doubts whether a real equal temperament has
ever been heard.

1 wish Mr. M. would inform us, and explain precisely,
what the system is which he tunes so dexterously on his
harp, by the melody alone, without striking consonances.
Had his instrument so tuned been intended for melody
alone, this mode of tuning might answer the purpose; but,
as each of the strings has various relations to other strings,
and a temperament of a diatonic interval, too small to pro-

2 E 2 duce

43(5 Reply to Remarks on musical Temperament,

duce a sensible effect in melody, will produce a very sensible
effect in harmony, I congratulate Mr. M. upon a power
which I never had the felicity or seeing exercised by any one
person.

Never having heard of such a writer as Eximeno, I re-
ferred to Dr. Burney's History of Music, and there learn
that Eximeno was possessed of eloquence, fire, and a lively
imagination ; but that his book has been called, in Italy,
*' a whimsical romance upon the art of music, in which he
discovered a rage for pulling down, without the power of
rebuilding. "

I have annexed, in compliance with Mr. M.'s request, the
beats of mean tone temperament in one second. I need
not add that, by taking the first decimal, the beats will be
obtained for ten seconds, which I would recommend. I
have also subjoined the beats of Mr. Marsh's System ; and
wish to be informed by that gentleman if he has had an
organ tuned according to this system.

Persons unacquainted with the theory of the beatings of
imperfect (that is, tempered) consonances, may object to a
table of beats, that so large a number as 80 or 50 in ten
seconds cannot be counted. For the information of these
gentlemen, I add, that no one can count these beats : in
fact, they rather howl than beat; but they necessarily result
from the temperament of the slowly beating consonance!
by which the temperament is laid.

I remain, Mr. Editor,
Yours, &c.

Norwich, Dec. 5, 1810. (J. J. SMYTH.

P. S. — Please to correct an erratum in my paper, p. 250,
second line from the bottom, for polichy read policy.

Mean Tone Temperament.

Beats in one Secund.

C

B
Bb
A

I
X

lb

D

480.

S.

III.

4.

Vth.

6. '1

448-6065

8-366

53-8099

5-5740

4-1755

0

429-3227

6b- 1522

0

5-8410

3-9793

80-4716

401-2438

7-4628

0

4-9886

3-7314

0

375-

6-9675

45-

4-6704

23-4212

0

358-8838

6-6883

0

4-4648

3-3122

0

335-4110

6-2410

40-2358

4-1755

3- 1 1 94

0

820-9972

50-9882

0

3-9793

2-9916

60-1936

SOC-

5-5810

0

.S-73I4

2-7870

0

287-1053

45-5768

0

23-4212

2-6705

58-8099

268-31'73

4-9878

o

3-3422

2-1943

0

250-7784

4-6704

30-0968

3-1194

2-3352

0

240.

44735 1

0

2-9916

2- 2424

45.

VI.

6-967*
6-6893
6-2470

40-9832
5-5310

45 5768
4-9870
4-6704
4-4735
4- J 880

34-0761
3-7314

Mr. Marsh's

Of the Bogs in Ireland.

437

Mr. Marsh's System.

Beats in one Second.

c

480-

3.

III.

4.

V.

6.

VI.

B

451-3838

18-3838

31-4802

2-3802

2-5306

17-7984

15-4250

Bb

48-2557

40-0412

10-6067

3-2066

2-4007

47-0736

14 7447

A

402*7338

16-4028

9-9734

3-0162

2-2478

15-8794

13-7622

m

378-7240

15-4250

26.3800

2-8758

8-0076

14-9330

29-9746

G

359-3272

14-7447

8-8992

2-6912

2-0140

14-1686

12-2794

#

337-9052

13-7622

23-5368

2-5306

1 -8994

13-3226

26-7434

F

320 5991

29-9746

7-9397

2-4006

1-7973

35-2398

10-9559

E

301-4859

12-2794

7-4665

2-2478

1-6901

11-8872

10-3023

Eb

286-0449

26-7434

7-0843

8-0076

1 -6033

31-4802

9-7755

D

268-9919

10-9559

6-6613

9*0140

1-5081

10-6067

9-1919

*

352-9553

10-3023

17-6199

1-8944

1-4379

9-9734

20-0206

C

240-

9-7755

5-9436

1-7973

1-3456

26-3800

8-2014

LXXIX. Copy of the Instructions given to their Engineers
by the Commissioners appointed to inquire into the Nature
and Extent of the several Bogs in Ireland; with further
Particulars respecting the Bog of Allen, and its Sub-
strata ; accompanied with a transverse Section of Lully~
more Bog, reduced from Mr. Griffith's S/ieet Section. By
Mr. William Fa key.

X he secretary of the commissioners appointed to inquire
into the nature and extent of the several Bogs in Ireland,
and the practicability of draining and cultivating them, is
directed by the Board to communicate, for the information
of theengineers who may be employed, and of the proprietors
of bogs, the mode in which they have been advised to pro-
ceed.

" 1st. — They propose to divide the Bogs of freland into
districts, and to assign each district in charge to one or more
engineers.

.< 2d.-— Each of the engineers is to provide a sufficient
number of assistants, for whose qualifications he is to be
responsible. ,

<< 3d. — The commissioners think it necessary to direct
the attention of their engineers to the particular heads of
inquiry contained in these instructions ; but it is by no
means intended to confine their judgement within these
limits ; on the contrary, where local circumstances point
out a preferable mode of proceeding, the commissioners ex-
pect that it shall be fully stated, in addition to the infor-
mation on the different points which they now suggest.

a 4th.'— -They conceive, that the first steps towards the
drainage of an extensive bog, should be to ascertain the

2 E 3 proper

438 Of the Bogs in Ireland.

proper lines of direction for one or more main drains pass-
ing through it, to give vent to the waters which it contains,
and for catch-water drains laid out along its edges, to inter-
cept the springs and streams which flow into it from the ad-
joining lands.

" 5th. — In laying down the situation of the main drains,
the engineers are to consider, not merely the general de-
clination of the bog towards the rivers or such or other na-
tural outlets as may best answer for their drainage, but to
keep in view the further object, where practicable, of con-
verting these main drains, either immediately or ultimately,
into channels of navigation, for the conveyance of the fu-
ture productions of the bog, and of providing for the con-
nexion of those navigable drains, where convenient, wich
the great lines of navigation already subsisting : where this
is not possible, they are to consider how these different
drains may be united to other canals, which may be formed
hereafter. In laying down the situation of any navigable
drain, the engineers are to attend to the situation of such
manures as may be most suitable for the bog.

" 6th. — Where the main drains are likely to be used as
i canals, they are not, in any instance, to be less than 14 feet
broad at bottom, and rive feet deep from the water surface.
The breadth and depth of other main drains, and of the
catch-water drains, must be proportioned to the quantity of
water which they are to discharge.

" 7th. — As there are no districts which are more liable
to the inconvenience of a total want of water in dry sum-
mers, than level tracts of marshy ground, when once their
drainage is effected, care must be taken in laying down the
direction of the main drains, to allow them, where prac-
ticable, to be occasionally dammed up, so as to raise the
water within two feet of the surface, for the purpose of

ftromoting vegetation ; and that the catch-water drains, in
ike manner, should supply water on the surface, for the
use of cattle, or for the purpose of irrigation, where the
mode of improvement shall be deemed advisable ; and in
situations where a sufficient supply cannot be procured by
these means, the engineers are to consider where reservoirs
may be most advantageously constructed, to be supplied,
in time of Hood, from the caich-water drains or rivulets in
the vicinity of the boos.

" 8th. — Where locks may be necessary, the dimensions
which the commissioners recommend are, feet, in-

Length 70 0

Breadth 7 3

Depth over the fill of the gates ..40

(i 9th. — Ib

Of the Bogs in Ireland, 43$

t< 9th. — In all cases where the bogs arc wholly or par-
tially surrounded by high land, whose natural inclination is
to the bog, the engineers are to consider where catch-water
drains may be necessary ; and as it will generally happen
that these catch- water' drains may admit of a greater tall
than it will be practicable to gi *e to the main drains, care
must be taken, where the catch-water drains are to join,
the main drains after their issue from the bog, that it shall
be at such a distance, or on such a level, as to preclude the
danger of the water to the catch -water drains, in lime of
floods, penning back the water of the main drains, so as to
overflow the bog. Where the levels will not admit of the
waters of the catch-water drains being conducted into the
main drains without being subject to this inconvenience,
provision must be made for conducting them through sepa-
rate channels into the river, or other place, where the waters
of the bog are to be discharged.

" 10th. — Each of the engineers is to prepare a map of
the district assigned to him, distinguishing,

" 1. The extent and boundaries of the bogs which it con-
tains.

" 2. The nature of the soil and country immediately con-
tiguous to each bog, particularly specifying the situations of
lime-stone, lime-sTone gravel, marie, or other manures.

" 3. The surface of the bog, whether firm black bog,
or shaking quagmire.

u 4. The situation of any springs, rivers, or lakes, which
appear to occasion the wetness of any of the bogs.

" 5. The course of any rivers, streams, roads, or canals,
by which the bog is intersected.

"6. The drains and other works proposed by the en-
gineers.

" 7. Such lines of new roads as appear most proper for
the carriage of manure, for carrying out the future produce
of the reclaimed bogs, and for communication with the
roads in the vicinity.

" 11. These maps are to be accompanied with sections,
delineating the surface and bottom of the bog, and the na-
ture and depth (as far as may be necessary) of the under
strata on which it rests.

*' 12. The maps and longitudinal sections are to be drawn
on a scale of four inches to an Irish mile, and the perpen-
dicular scale of the sections to be ^ inch on the foot.

" 13. They are to be accompanied with index maps, on
the scale of one inch to a mile.

" i4. In taking the levels necessary for determining ths
* 2 E 4 sscuoni,

440 Of the Bogs hi Ireland.

sections, the engineers are to take care that their assistants
proceed^ in all cases, so as to cross and correct each other.
The engineers are to be responsible for the correctness o£
the whole.

" 15. The main drains are generally to be laid down so
as to allow the collateral drains communicating with them,
to embrace the greatest extent of surface the nature of the
bog will admit of: but where the inequalities of level in it*
surface, or the outlets of discharge for the waters, present
a. choice of plans for its drainage, so as to induce any doubt
in the mind of the engineer which plan mav be most eli-
gible, he is to submit the different plans to the commisf
sioners.

if 16. The engineers are to accompany the maps with
written reports, containing generally whatever occurs to
them on the subject of the drainage of the districts assigned
to them, and particularly specifying,

*c 17. The probable expense of such drains, roads, ca-
nals, locks, and other works, as they recommend.

W 18. The names of the proprietors who claim any right
or interest in the bogs, and to what extent, and in what
proportions, as far as they can learn.

" 19. Whether any, and what tracts of bog in their di-

, stricts have already been reclaimed, and what have been the

manures used, and the modes pursued, in their amelioration,,

and what is the nature and the state of the crops which

they actually produce.

^ 20. The probable value of the land when reclaimed,
and the mode of culture which maybe the best adapted for
it, particularly distinguishing those parts that may be best
suited for planting.

*f 21. Where any of the bogs proposed to be drained are
at present used for the supply of fuel, the engineer is to re-
port how far the quantity and quality of the fuel is likely tq
be injured or improved by the works which he recommends.

" 22. Where the wetness of the bog appears to be occa-
sioned by a lake on a higher level, the engineer is to report
on the practicability and means of draining the lake; and
also on the difference of levels in summer and winter of all
rivers and lakes connected with the bogs.

" 23. Where the botlqm of the nog is lower than the
river into which it would be convenient to discharge the
waters of the drains, the engineer is to report on the prac-
ticability of lowering the river sufficiently to receive them.

" 24. As in many instances the levels may not admit of
the bogs being drained in the usual planner, in such cases

th«

Of the Bogs in Ireland. 4 4 1

the engineer is to take into consideration the propriety of
draining it by means of wind-mil] pumps or other ma-
chinery; the expense of erection, and annual charge of
which, he will include in his report.

" 25. The engineers are further to consider what situa-
tions may best answer for the corn- mills which may become
necessary, in consequence of the increased tillage of the re-
claimed districts, and how far the water of the drains may
be used in working them ; and they are particularly to in-
quire as to the situations and circumstances of such mills
already in existence, the supply of whose water may be af-
fected by the projected drainages, and to consider and re-
port, whether it be most expedient to provide reservoirs for
their supply, or to purchase the interest of the proprietors.

" 26. They aie also particularly to report, where any of
the proposed works appear likely to diminish the supply of
water for the Grand or Royal Canals, or other navigations,
or to interfere with their levels or embankments ; and in
what manner such injuries may be best obviated.

f* 27. In order to connect the respective purveys with
each other, and to enable the commissioners to judge how far
these drains may be applied to the purposes of internal na-
vigation, they propose to direct, that the engineers to whom
the districts nearest to Dublin may be allotted, shall ascer-
tain with the utmost accuracy, the difference of level be-
tween the levels in their maps, and of the platform on the
capital of the column erected in the memory of Lord Nel-
son ; and to communicate the difference of level to the en-
gineers who may have districts immediately beyond them,
for the purpose of carrying forward the comparison. The
commissioners intend afterwards to request the Ballast Of-
fice to mark at the Pigeon House Dock the level of high
water in an ordinary spring-tide in the Bay of Dublin, so
that by determining the difference of level between that and
the platform on the column, the difference between the level
of the sea and the various levels which are to be taken in pur-
suance of these instructions, may be correctly ascertained.

" 28. To enable the commissioners to complete the con-
nexion of the surveys by trigonometrical observations, if
such should hereafter be deemed expedient, the engineers
are to have permanent marks at the extremities of the several
levels, and to lay down all remarkable objects which are
likely to be permanent, such as raths, towers, castles,
cairns, hill -tops, market-houses, &c.

u 29. The various lines cf levels are to be shown on the
map by dotted lines.

" 30. The

442 Of the Bogs in Ireland.

t€ 30. The engineers are to act under these instructions,
in respect to all such bogs within their districts as contain
by estimation or repute more than 500 Irish acres ; of hogs
of inferior extent, they need only report the existence arid
situation.

" 31. The commissioners intend to provide the best
levelling instruments, which they will supply at the original
price to such of the surveyors employed as are not already
furnished with instruments of sufficient accuracy. They
intend also to procure some rain-gauges, to enable them to
determine the dimensions of the principal drains. They
request that any gentleman disposed to assist bv keeping an
account of the rain in the vicinity of the bogs, will be so
good as to signify his intentions to their secretary.
By order of the Board.

Dublin Society House, £. McCarTH^,

sept. 28, 1809. Secy tQ the Commissioners.

ADDITIONAL INSTRUCTIONS.

" 32. The commissioners have determined to alter the
longitudinal scales of the sections referred to in the twelfth
article of the instructions, from eighty perches to an inch
(as therein directed) to forty perches to an inch, the scale
which on further consideration they have preferred to adopt.

M The perpendicular scale of the sections (namely ■^s-
inch to a foot) is to continue unaltered.

" 33. As it will probably be found inexpedient to incur
the expense of engraving the drawings of the sections, re-
ferred to in the eleventh article, of the inductions, the en-
gineers are to specify the lines of sections, and the amount
of fall in each in their reports ; and further to specify them
upon their maps, so far as they may find it not inconve-
nient to do so.

"34. The commissioners have determined that, it will
not be necessary (at least for (he present) to execute the
index maps referred to in the 13th article of the instruc-
tions.

" 35. The engineers are to prepare, for the purpose of
being presented to parliament, maps on the scale of two
inches to an Irish mile, reduced from their large maps, spe-
cifying every thing contained in the large maps. These re-
duced maps are to be sent in along with the reports of the
engineers to the commissioners. The largest sized copper
plate that can be allowed for these maps is twenty-six inches
Jong by twenty broad. Where the district is so large that a
map of the whole of it cannot be contained within these

dimensions,

Of the Bogs in Ireland, 443

dimensions, the engineer must consider how the district
may best be subdivided.

" 3d. The engineers are in all cases, both in their maps
and in their reports, to express the contents of the bogs,
both in Irish and English acres, and also to insert in their
maps, scales of both Irish and English miles.

" 37. The commissioners not judging it expedient for
the present to lay down a meridian for the purpose referred
to in the twenty-eighth article of their instructions, consir
der it sufficient that the engineers should construct their
maps upon the magnetic meridian, the north of the mag-
netic meridian pointing to the top of the map, and the me-
ridian line being parallel to the sides of it.

M 38. The estimates referred to in the seventeenth arti-
cle of the Instructions, arc to include all the expenses,
which in the jui .'..■■ c men t of the engineer will be necessary to
reduce the bog to such a state that it shall be ready to receive
agricultural improvements. These estimates are however
to distinguish the expenses of the different descriptions of
works, and or the different classes of drains recommended.
By order of the Board.

Dublin Society House, B. McCUrTHV,

M&y 16» l8l°- Set* to the Commissioners.

To Mr. Tilloch.

Sir, — Having as an exercise, by direction of my father,
reduced Mr. Richard Griffith's large section across the Bog
of Lullymore, so &s to agree in scale of length and in po-
sition nearly, with his map of this bog, printed in the 1st
Report to Parliament on the Bogs in Ireland, from which
you gave some extracts in your last number, and distin-
guished therein alkthe proposed drains, and shown by ar-
rows whether they run northward (up) or southward
(down), I ta£e the liberty of sending a copy, and perhaps
you may deem the same worth a plate in a future number of
yourMagazine, in order to explain, as it does (see Plate X.),
the uneven surface and variable thickness of the peat in
these vast bogs, the uncertain thickness and existence of
the alluvia] yellowish blue clay, (No. 10. in your last num-
ber, p. 371,) on which the peat frequently rests, and the
very uneven and undulating form of the great bed of allu-
via, clayey limestone gravel, of vast thickness, which forms
the floor and borders of this and most others of the bogs of
this part of Ireland^ except in a few places where strata

appear,.

444 Of the Bogs in Ireland.

appear, according to the report which Mr. Griffith, jnn.
has made on the subject; wherein, p. 15 and 16, the tract
of land called the Island of Allen is thus described : —

<c The surface of the Isle of Allen rises very quickly
from the bog on all sides, particularly to the north-west,
where it is composed (at least to a considerable depth) of
limestone gravel, forming very abrupt hills, in those places
where the face of the hills has been opened for the pur-
pose of raising stone and gravel, the mass is con-posed of
rounded limestone, varying in size from two feet in dia-
meter to less than one inch ; the largest are not so much
rounded as the small, frequently their sharp angles are
merely rubbed off; they are usually penetrated by contem-
poraneous veins of Lydian stone, varying in colour from
black to light grey; the colour of the limestone is usually
light smoke grey, rarely blueish black ; when it is, the
fracture is large conchoidal ; that of the grey is uneven,
approaching to earthy.

" The Lydian stone, when unattached to the limestone,
has usually a tendency to a rhomboidal form, sometimes
cubical, the edges are more or less rounded, the longitu-
dinal fracture is even, the cross fracture is conchoidal.

" From the strong resemblance that subsists between the
rolled limestone and its accompanying substances, and the
upper beds of the limetone strata, which extend from the
county of Tipperary, through Kilkenny, (where the lower
beds are used for marble,) Carlow, Queen's County, King's
County, Kildare, Meath, Westmeath, Dublin, &c. &c.
there can be no doubt that the least accumulation of lime-
stone gravel, which nearly covers the whole province of
Leinster (forming steep ridges of hills frequently above 300
feet high, and sometimes approaching the summits of lofty
primitive mountains) did originally form the upper beds of
the ljmetone strata, which when now found in situ are sel-
dom firm, on account of their alternating with thin beds of
slate, clav, usually much decomposed, and their being tra-
versed by numerous fissures and veins of calcareous spar and
Lydian stone.

" It is much moredifficult to trace the course of the cur-
rents which first removed the limestone from its native bed,
and afterwards having rolled the detached masses backwards
and forwards, deposited them on the sides of hills, whose
base had withstood the action of the waters, or by cross
currents and eddies formed independent hills and minor
ridges, the deposition of which, together with a subsequent
deposition o.f a bed of clay, varying from one to six feet

in

Of the Bogs in Ireland. 445

in thickness, and which almost universally covers the sur-
face of the gravel, by obstructing the course of the waters
in a country having naturally but little fall, may, by creating
a general stagnation in them, and thereby forming extensive
shallow lakes, have caused the growth of the Sphagnum
paluslre*, and other aquatic mosses and plants, of which
the mass of our bogs is composed.

" This island, though separated from the southern range
of hills by a low boggy valley, may on a general view be
considered as a continuation of that range.

te Perhaps a short geological description of this ridge,
'which, on account of its height and steepness, forms the
most prominent and interesting feature in the county,)
though apparently foreign to the general object of this re-
port, may (by preventing ignorant people from search-
ing for limestone and other manures where they do not
exist) be considered as an useful and necessary appendage.

u Near Ballyteague Castle, in the northern edge of the
Island of Allen, stratified limestone makes its appearance
at the surface, dipping 20 degrees east of south, at an angle
of 5 degrees from the horizon. The stone is principally
used for building, as on account of its containing a large
proportion (according to my analysis 15 per cent.) of silex,
it requires much fuel to burn it into lime.

" The next rock visible crops out about two miles to the
•outhward of Ballyteague, at the base of the Hill of Allen
near the village called the Leap of Allen, the intermediate
country being covered by hills of limestone gravel ; it is a
species of conglomerate, composed of rounded quartz peb-
bles, varying in size from minute sand to six inches in dia-
meter, connected together by a red iron-shot, argillaceous
cement ; then beds of a deep brick red slate ; clav much
interspersed with mica is found interstratified with the
conglomerate : the dip is 30 degrees east of south at an
angle of 7 degrees from the horizon. Southward of this
quarry, rises the Hill of Allen, a very steep conical hill
about 300 feet high (reckoning from its base) ; it is com-
posed of an irregular unstratified mass of fine-grained green-
stone, the crystal of hornblende and feldspar being very
minute ; transparent calcareous spar is frequently observable
in the mass, rarely large crystals of feldspar are found in-
terspersed ; the rock on approaching the summit of the hill
becomes more crystalline, detached masses of beautiful por-
phyretic greenstone thickly studded with large crystals of

* Bog Mom.

fold-

446 On Refraction,

feldspar, are frequently to be met with on the surface : I
did not find any of this rock in its native bed.

" The hill called the Chair of Kildarc and Dunmurry
Hill, situated to the south-west of the Hill of Allen, are also
composed of greenstone* ; the Red Hills are conglomerate.

" Besides the general ridge which (with the exception of
two low passes through which the bog rivers flow) sur-
rounds the district, and the Island of Allen which divides
the interior, there are frequently minor and more detached
ridges, usually of moderate elevation, bounding the several
bogs, and preventing the passage of the waters to the rivjrs-
or principal streams, which usually run in valleys beyond
the ridges, and nearly parallel to the ed^e of the bogs.

" These interior ridges, where there is no river, usually
form the line of separation between different begs."
J am, sir,

Your obedient servant,
William Farev.

LXXX. A short Account of the Improvements gradually
made in determining the Astronomic Refraction. By
Afr.T. S. Evans, Master of the Mathematical School at
New Charlton, near Woolwich, Kent ; late of the Royal
Observatory, Greenwich, and oj the Royal Military Aca-
demy, Woolwich.

[Continued from p. 349.]

It would be endless to notice the different opinions re-
specting both the terrestrial and the astronomic refraction
which are to be met with in the writings of various authors
on the subject : and it would be equally useless to notice
all the tables of its quantity given by them, some of which
differ very much from others. It will be sufficient to men-
tion those only who made some considerable advances to-
wards obtaining it with greater accuracy.

The next of these in order was La Caillef, who in de-
termining it certainly bestowed very great pains, by making
and reducing an immense number of observations, and
afterwards comparing them with others made at Green-
wich by Dr. Bradley, at Gottingen by Mayer, at Bologna
b\ X noiti, and by La Laurie who was then at Berlin.
From these it appeared that the refraction at 45 3 of altitude
was tif3 u" ; but ibis, as will hereafter be seen, Was too great

* This is the first discovery of rock ef the trap formation in this part of
ftrafa d.

f Mem. dc i'Ac de Sc. 1755, p. 547.

by

On Refraction, 40

by some seconds. In his paper on the subject, which is
divided into four parts, he proves, first, that the mean re-
fractions are very nearly the same ibr the same apparent al-
titudes throughout the whole extent of the temperate zone;
since those which were observed at Paris did not exceed
those observed at the Cape of Good Hope but Vp-at most.
In the second he determines the absolute quantity of the
mean refraction for the apparent height of the pole at Paris,
and gives the result of his observations with regard to the
latitude of Paris and of the Cape of Good Hope. In the
third he gives his table of mean refraction, and another of
corrections depending upon the state of the barometer and
thermometer; concluding with some reflections on its con-
struction and use. In the fourth he compares his new table
with the most celebrated of those that had before that time
been in use among astronomers ; and he then shows how it
agrees with the observations of Bradley, Zanotti and Mayer.

But by La Caille's Memoir * it appears, that previous to
this time M.Mayer had formed and communicated to him a
table of astronomic refractions which he computed by means
of an algebraic formulaf, the coefficients of which he de-
duced from his own observations, and took into account the
variations relative to thoseof the barometer and thermometer.
He found the alteration of refraction for a depression of 1 5
lines in the barometer, the same as for a rise of 10 degrees
in the thermometer, and the fariation for each degree of the
latter, according to his table, -^ of the whole mean refrac-
tion, which he adapted for 28 inches of the barometer, and
0° of the thermometer^. This proportion takes place down
to 80° of zenith distance. Mayer considered also that the
mean refraction is the same for all parts of the earth ; and
that the only variation which takes place, depends on the
changes of the § weight and temperature of the atmosphere.

La Caille,in comparing Mayer's Table with observations,

* Mem. 1755, p. 555. + Vid. Mayers Tables, 1770.

$ French measure and Reaumur's therm.

$ It was perceived that the refraction near the horizon at Paris is sensibl/
affected by vapours, and the smoke which arisen from the city, situated north
of the observatory. Exhalations and the moisture of the atmosphere have
certainly a considerable influence on it, and so has the situation of the place,
being more or less elevated. The neighbourhood of a city, mountains or
hills, forests, rivers, or marshy plains likewise affect it much ; and La Caille
was persuaded that an astronomer never had refractions purely celestial near
the horizon, that is, of the nature of those 20° above it ; local circumstances
producing such considerable differences in them that he did. not choost
to insert in his table those for altitudes below 6°. Cassini de Thury be-
lieved that the refraction and its inequality were greater at Paris under similar
altitudes, on the south side than on the north, and at 4° he found it 20" more.
Mncyci. Meth.

found

448 0?i Refraction*

found that his correction for the thermometer was a littid
over- rated ; and accordingly, for his new table, altered it
to Vr *or eacu degree. And here it may be observed that
La Caille did not correct his altitudes above 36° at Paris,
and 30° at the Cape ; first, because he only noted the baro-
meter and thermometer in the night, when he observed
stars below 30° of altitude. Secondly, because, that at 36}
of altitude, where the mean refraction is about !•£■ minute,
the variation which belongs to 10 degrees or' the thermo-
meter only amounts to 3£ seconds ; a quantity about equal
to the limits of the errors of observations made with an in-
strument of six feet.

The formula given byEuler* appeared also about this
time. It took into account the variation of the refraction
depending upon the thermometer and barometer, but was
certainly too complicated to be generally adopted. He shows
however, that in very different hypotheses the refraction
will be sufficiently exact, if taken in the inverse ratio of the
degrees of heat, when the star or planet is not too near the
horizon, but the precise quantity of this ratio was unknown
to him.

In this state the refraction stood when Dr. Bradley took
the subject into consideration, and began to find its quantity
from his own observations. The rule which he adopted,
although a very elegant one, he neither lived to complete
nor to present to the world ; but it was published after his
death by Dr. JMaskelyne f, and has commonly been used
in England up to the present time. He found the mean re-
fraction at 45° of altitude 57", and, that at all other alti-
tudes it was equal to 57" multiplied by the tangent of the
zenith distance, diminished by three times the refraction.
Then supposing the mean state of the atmosphere to be at
29*6 in. of the barometer, and 50° of Fahrenheit's thermo-
meter, he made the true or corrected refraction equal to

57" x ,,(Z.D.~Sr) xb^: x -ggl. where it is to be

understood that the mass of air is supposed to increase in
bulk TJ-0- for each degree of Fahrenheit's scale.

A variety of experiments have been made at various
times to ascertain the increase in bulk of a quantity of air
represented by unity for a certain number of degrees of rise
of the thermometer. The following is a list of some of
them J : —

* Mnj. de l'Ac dc Berlin, 1754, p. 131.

f Pief. to 1st vol. of Obs. 1765. Phil. Tram. 1764 and 17S7, p. 157.
Req. Tables, &c.

f Sec La Landes Astr. 2241. 3d ed. Thomson's Chemistry, vol. i. p. 489.
La Place's Mec. Ce!. vol. iv. p. 270. Phil. Trana. 1809, &c. &c.

On Refraction. 440

for 1»

M. Bonne 1-00 25777

Bradley. 1 00 25000

Dalton 1-00 20701

De Luc 100 20388

Fahrenheit , TOO 25777

Gay Lussac 1 00 20868

Gioombridge 100 21000

Hawksbee 100 00*033

La Caille POO 22222

Mayer 1*00 20444

Shuckburg , 1*00 22222

Mean of all except Hawksbee's . . 100 2240,0

The refraction deduced from Bradley's very neat and
simple formula was in a few years adopted by nearly all
the astronomers of eminence throughout Europe, The ex-
treme facility with which it might he computed, and the
corrections applied, whether from the, formula itself or from
tables ready calculated for that purpose, was a powerful re-
commendation in its favour ; but its near agreement with
observations soon established it.

In 1805, the very ingenious and profound M. de la Place
in his Mecavique Celeste* favoured the world with a chap-
ter on this subject, wherein he has displayed as much saga-
cious penetration as deep mathematical learning and ability.
He begins with considering the trajectory of a ray of light
traversing the atmosphere; and by supposing all its layers
spheric, and of variable density, according to some function
of their height, he deduces a differential formula for the
refraction whose integral he then finds ; but, he observes,
this equation supposes that the refractive forces of the layers
of the atmosphere are directly proportional to their density,
which is the result of Hawksbee's experiments. Never-
theless, it is possible that this assumption may not be
strictly correct, and it would be useful if more experiments
were made on the subject. He then find! that the hypo-
thesis of an uniform temperature is erroneous, as well as
that of the density decreasing in arithmetic progression,
when the height increases in a similar progression ; and he
says, " the constitution of the atmosphere being com-
prised between the two limits of a density decreasing in
arithmetic progression, and of one decreasing in geometric

* Vol ir, page 231.
Vol. 36. No. 152. Dec. 1S10. 2 F pr?-

450 On Refraction*

progression, -therefore an hypothesis which participates of
both these progressions would seem to represent the re-
fraction, and the observed diminution of heat in the at-
mospheric layers ; accordingly he makes this curious as-
sumption, and deduces a formula by means of it.

He then applies the same analysis to the finding of an
equation for the retraction at altitudes below 12% and gives
us an expression which has the advantage of being inde-
pendent of all hypotheses respecting the constitution of
the atmosphere, resting only upon the nature of it in the
place where the observation is made, as indicated by the
barometer and thermometer, after which he determines the
value of his coefficients. With respect to that depending
upon the thermometer, he requested M. Gay Lussac to re-
peat his experiments, with all possible care, by graduating
his thermometers exactly, and by paying the gteatest atten-
tion to dry the tubes well, which he made use of: for it
appeared to him, that upon this depended principally the
great differences in the re suit 9 hitherto found by philoso-
phers. Attending well to the expansion of glass*, and to
the corrections on account of the variableness of the baro-
meter, during each experiment Gay- Lussac found, by a mean
of twenty-five experiments, that a volume of air expressed
by unity at zero of temperature of the centigrade thermo-
meter became 1*37.5 at the heat of boiling water, under a
pressure equivalent to that of a column of mercury = 0*76
of a metre in height.

The other coefficient was determined by M. Delambre,
who, by comparing a great number of observations, found the
refraction to be 186'"f28at 50'of apparent altitudef,thetem-
perature being zero, and height of the barometer 0* 76 metre.

After this he proceeds to consider the effect of moisture
in the atmosphere, and concludes the following values for
the increase of the refraction, for extreme humidity in the
air from 15' to 45- of temperature.

Degree--. Increase of Refraction.

15° 0-.563" t, 0

20 0-/14 /, 0

25 O977 t, 0

30 1274 t, 0

35 1-051 t, 0

40 . .2-122 ty 0

Where 0 represents the apparent altitude.

* Upon this and some other points connected with the subject of this
•viper, see Thomson's Chemistry, hook i, cliv. '.?, seel. 4, edit, of 18 iO.

'• According to the new centesimal division of the circle; hut this, ac-
^ to our division of the circle, will be 60" 499872 at 45° of apparent

-, when the barometer is 29 92152 EugL in., «:ud Fahrenheit's theun.

cord*.
altitnj*

On Refraction. 451

" It results from this table," he says, " that the effect of
moisture iu the air on the refraction is very small ; the ex-
cess of the refractive power of the aqueous vapour on that
of the air being compensated in a great measure by its less
density. We may nevertheless attend to it by means of the
preceding table, in cases of extreme humidity. Observa-
tions of the hygrometer will point- out the ratio of the quan-
tity of vapour spread in a given volume of air to the quan-
tity which would produce extreme humidity in this volume*
The increase of refraction which corresponds with extreme
humidity must then be multiplied by this ratio. " He con-
cludes the subject with the following remark :

iC If we would take into account the figure of the earth
in the theory of refraction, it is to be observed that at the
point where the observer is situated, we may always con-
ceive an osculatory circle to the surface of the earth, whose
plane passes through the star: now the figure of the atmo-
spheric layers is very nearly the same as that of the earth ;
the circles, concentric to the circle in question, are there-
fore oscillators likewise of these different figures; and we
may determine the refraction of the star by supposing
the earth to be spheric, and of a radius equal to this oscula-
tory circle. Thus wee see, 1st, That the refraction always
takes place in the vertical plane: 2dly, That it is not the
same on all sides of the horizon, since the oseulatory cir-
cles are not the same in every direction; but we may rest
assured, that the error is insensible, when the star is a little
elevated. At the horizon, however, differences of some se-
conds may occur." Thus terminates one of the most
masterly chapters on this subject ever written ; after which
he proceeds to treat of the terrestrial refraction.

Upon these theorems * found by La Place, reduced to
rather a more convenient form, and with coefficients differ-
ing a little from his,Delambre has computed a set of Tables
bv means of which the refraction may be found with great
facility. They were first published by Puissant f in a work
closely connected with this subject, and are well arranged
for use. The first of them gives the refraction for every
degree of apparent zenith distance down to SO', and for
every 30' from thence to 00\ They are adapted for 0*71
metre -of height of the barometer, and 35° of the centigrade
thermometer]:. Besides the refraction and its difference for

* Paje 27 1 , and page 264 of the Mecan. Cel. vol. iv.
f Traite de Geodesic, fit the end, 4to, 180J. J Or, £7 953 English

inches, and 0j° of Fahrenheit's thermometer.

2 F 2 each

452 On Refraction,

each degree, there are given the logarithms of the refraction
in seconds and their differences : and in two auxiliary tables
are given the logarithms of the factors for correcting it for
the variations of height in the barometer and thermometer.
To make these corrections depending upon the temperature
always affirmative as far as the table extends, he has added
respectively to the logarithms of the two last tables their
greatest negative logarithm taken positively, and subtracted
from it the logarithms of the first table.

To this succeeds a Table of mean refractions for true di-
stances from the zenith for every degree down to 80 , and
for every 10' thence to Ql°, with their differences, adapted
for 0" 76 metre of the barometer, and 12°\3 of the centigrade
thermometer*, with two auxiliary tables for reducing it to
any other state of the atmosphere. Directions are also
given for using them, together with the formulae from
which they were computed, reduced to a more simple
form. %

In noticing the latest improvement made in this subject,
for which we are indebted to one of our own countrymen,
it is but fair to return him those acknowledgements to
which he is so justly entitled. When gentlemen of for-
tune give up the gay amusements of the world, and turn
aside from the pleasures of fashionable life, to cultivate
science in retirement, they deserve our warmest thanks : and
when we add to this the consideration that the science
they cultivate is not only one of the most interesting and
sublime, but of the utmost importance to a commercial na-
tion like Great Britain, our thanks certainly must be changed
into something more like gratitude.

There are, indeed, very few who can afford to purchase
instruments of sufficient accuracy to make improvements
in a science so far advanced; and still fewer of those that
so amply possess the means of life, who would bestow that
time and attention which are requisite in acquiring the ne-
cessary knowledge forlhis purpose, and turning it to useful
account.

Such is the present state of the navy of England, and
her maritime concerns, that the improvement of astronomy
is a subject which calls seriously for attention; more espe-
cially, as we have but one public institution for that pur-
pose. The commerce of France is nothing in comparison
of ours, yet the greatest encouragement is given in that
country to those who promote every science connected

* Or, 29*92152 English inches, and 54° 5 of Fahrenheit's thermometer.

with

On Refraction. 453

with the navy ; whilst it is well known, that at this mo-
ment a few of our best mathematicians are groaning tinder
insults, degradations, and injuries, as severe as they are un-
provoked and undeserved. Had France the tenth part of our
naval power, with her present number of scientific men, the
whole world must soon be subjected to her dominion : and
where so much is at stake, it behoves us, by giving all the
encouragement in our power, to place -our navy as much
above that of other nations in scientific knowledge, as it is
in all other high and great qualifications.

The gradual decrease of the study of mathematics in this
country has already been publicly noticed*; but its cause?,
although very evident, have not yet been mentioned. Per-
haps, at some future period, this may form the subject of
another communication. I have been led into this digres-
sion by considering the still more deplorable state if possi-
ble of astronomy, which at this moment is scarcely culti-
vated by half a dozen persons throughout the whole king-
dom. But to return.

It has been doubted, notwithstanding what is stated by
La Caille, \vhether the mean refraction of France be the
same as that of England,. What gave rise to this was the
use of Bradley's Table in the determination lately made
there of the obliquity of the ecliptic, wherein a difference
of some seconds was found, between the result obtained
from observations made in tthe winter solstice, and that
from others made in the summer. This doubt has not yet
been satisfactorily removed : but the very accurate astrono-
mic circles lately made by our English artists, who are un-
doubtedly the best in the world, will, it is presumed, with
good assistance from theory, not onlv soon decide this
question, but furnish us with such observations as will de-
termine the refraction to a second, till we approach near the
horizon.

A very material step has lately been made towards this,
by the publication of Mr. Groombridae's valuable paper on
Refraction f, wherein he has determined, by a great number
of very accurate observations, both the quantity of mean
refraction at 45°, and the coefficients for correcting it on
account of the state of the atmosphere. The former of
these he makes 58"*] 192 by a mean of a great number of
observations, when the barometer is at 29*6 inches> and the

* Edinburgh Review of La Place's Mecanique Celeste.
f Philosophical Transactions for 1810.

2 F 3 mother-

454 On Refraction.

thermometer 45° of Fahrenheit without, or 4 9° within, which
he considers as the mean state of the atmosphere*. With
respect to the latter, he finds the multiplier for all degrees
below 49° within, to be -0024 ; and above! 40° within,
•0023 f: but for those above or below 45° without, he finds
it -0021. Instead, however, of the number 3, which Dr.
Bradley had adopted for his coefficient of r, Mr. Groom-
bridge finds that 3*3625 agrees better with observations ;
consequently his numbers and coefficients will give us the
following four equations.

1st. For the thermometer within, and below 49°, putting
d = 49 — A.

Refr". = 58"-lI9'iX/,(Z — 3«3625r) x — —. x (1 -}- -002k/).

2dly. For the thermometer within and above 49", put
d = /i — 49.

Refr". = 5S"-1192x£,(Z — 3'3625r)x— -g X (1— 0023J),

3dly. For the thermometer without and below 45°, put
d = 45 —h.

Refr". = 58"'1192 X/,(Z — 3-3625r) x -■ X (1 -f-'002ld),

4thly. For the thermometer without and above 45°, put

d = h —45.

Refr". = 5S"-1192X£,(Z — 3*3625r)x— -^ X (1 -•0'021 d).
Or, in logarithms :

1st. Thermometer within and below 49°, put d = 49° —h°f
then :

L. tan. ( Z r ) + L.&-f L.(10000 + 24^) -f

6*29303 == L. Ref."

* Mr. Kirwan states that the mean temperature of any place is equal to
84 — Sis'2, latitude. According to (his the mean temperature of Blackheath
would be 5^°8, but its exposed situation may possibly be the cause of this
•mall difference — Estimate of the Temperature of different Climates, or Dal-
ton's Meteorological. Observations, pa;-;e 160.

f Mr. Palton found likewise that the expansion of air from 55° to 1S3§,
or for the first 78.;", was 167 parts, whilst th6 expansion irom ISS^* to 212°,
or for the next 78£°, was only 1 58 parts, or nine less i hjU> 1 lie former. So that
it appears there is a difference between the expansion of air for the high de-.
grees and that for the low ones. — Manchester Memoirs, vol. v.; or Thom-
son's Chemistry, vol. i. p. 490, edit, of 1810.

2d. Ther-

On Refraction. 455

5d. Thermometer within and above 4Q°, put d = k° —49°,

then :

L. /,(Z _-~£r) +L.'£ + L. (IOOOO - 23d) +

6-29303 as L. Ref."
3d. Thermometer without and below 45°, put d = 45° — A0,

then :

L. /,(Z - *?!&*) + L.fl + L.(10000 + 81.4 -!'
6*29303 as L. Ref."
4thly. Thermometer without and cZw;e 45°, put d =
/i°-_450, then:

L. /,(Z - ^| -r ) + L. £ + L.(10000 - 9ld) +

6-29303 = L. Ref."
But as it appears more simple to avoid the two numbers
49 and 45,, and reckon the state of the thermometer from
zero, we may reduce the whole of these equations to that
temperature, and then find other multipliers for the number
of degrees above that point ; which is easily done as fol-
lows .- Put R as the refraction at any given temperature;
r = the degrees of that temperature, § = the refraction at
Zero, n = the multiplier for the state R, and v = that for
zero : then we have

R 4- Rrrc = R (1 + rn) = §; whence R = ~— ; but

on the contrary, p — grv == R = f (1 -- *>}j consequently,

c(l — rv) — — - — , from which we get v = — : then,

^v ; l+rn9 c r/*+l *

by substituting Mr. Groombridge's multipliers for w, we get
the new multipliers for reducing the refraction from zero
to any other temperature. By this we also obtain the ad-
vantage of having only three equations instead of four;
which, putting h as height of thermometer above zero, will
now be as follows:

1st. From zero to 49°, within.

5S • 1192 X 1 • 1 1 76 tan. ( Z Lr ) X ■ x

V 80 J 296

(1 — h -002147) = R/

2dly. For all degrees above 49 within.

58"-1192x P127 X^(Z-igr) X -~ X

(1 —A -002067) = R."

2 F 4 3d. For

4b6 On Refraction,

3d. For the thermometer without.

269

58"-1192 X 1-0945 t9 (Z - - yr)

80 ' 29-6

(1 — h -001919) = R."
Or, in logarithms:
1st. From zero to 49° within,

L. t, (Z - -8q r) + 0-3413143 -{- L.# + L.(l -h

•002147) = L.R."
2dly. Above 49° within.

L. t, (Z ~-r) -f 0*3394060 -f L.l -f-L.(l — h

•002067) = L. R."
3dly. For the thermometer without.

L. t, (Z — -^Tr) + 0-3322437 + Li-fL,(l-i
* oO '

^001919) =L.R."
In these equations, although very simple, there is
some little arithmetic trouble in computing the first and
last part of each expression. As to the first, it will be
easiest done by a table of the product of 3-36-25 into each
of the nine digits: by means of which the product of this
number into any other will readily be obtained, by only
adding that of its several digits, into 3-3625. Or it may

be done by multiplying r by — ■ ; or, by the following ex-

3x0 1

pression 3*3625 r = — - r — ftn **> which will only re-
quire contracted multiplication and division.

The last may easily be effected by a very ingenious and
simple method pointed out by M.Cagnoli*. Thus it is
well known that cos.1 = rad.2 — sin.3; therefore putting
x = 1 — lmf and comparing it with the latter of these
two expressions, \\e have

c\ A = r1 — s1, A as 1 — hn ad x:

consequently s, A = s/ hn and the square of the cosine
corresponding will be equal to x. Whence we have this
rule. To the logarithm of h add the logarithm of ?/, and
divide the sum by 2. Seek this number in the Table of
Logarithmic Sines, and take out the logarithmic cosine cor-

• Trigonometry, 2d edit. 4to. Paris 1808, p. 95, or 1st edit. 1787, p. 102.

responding

On Refraction. 4 57

responding to it, which is readily done at the same opening
of the book. Double this logarithmic cosine, and it is the
logarithm required of 1 — h?i*.

But in a letter dated 17th September 1810, which I
had the honour to receive from Mr. Groombridge, he in-
forms me that he has calculated on the data before men-
tioned a Table of Refraction for every io'down to 70° of
zenith distance; for every 5' from thence down to 86°;
for each 4' thence to 88°; each 6 thence to 89°; and for
everv %' from thence to 90° 18': together with an auxiliary
Table for the correction depending on the difference of the
barometer and thermometer from the mean state. He has
also contrived some very simple methods of performing
with great facility whatever arithmetic operations may be
requisite in using them. Every sincere lover of the science
will no doubt join with me in requesting that these tables
and methods may form the subject of another communica-
tion to the world, whereby it is presumed the mode of find-
ing the refraction will be made extremely easy, and an im-
portant service rendered to astronomy.

As an appendix to what has been said on the refraction,
I shall take the liberty of adding the following method of
finding the sun's parallax, which is rather more accurate
than as it is usually given in the Tables. Add together the
logarithmic sine of Ike sun's zenith distance, the logarithmic
distance for the given day taken from page iii Nautical Al-
manack, and the constant number 094151 : their sum, re-
jecting the tens in the index, will be the logarithm of the
sun's parallax in seconds.

It must however be observed, that 1 have taken the sun's
mean horizontal parallax at 8"*74: for it was found f by
observations made at the Cape of Good Hope, as well as
others made by M. Pingre and Mr. Short, 8"*8; by M. du
Sejour, 8*84; by M. Lexell and M. de la Lande, 8"*6.
The mean of these six determinations is 8"* 74, which is the
quantity we have adopted above.

* When the thermometer is below zero, this expression will of course
become 1 + f>n, in which case it may, as above, be compared with 1 + f1 —f1.
but instances are extremely rare where any necessity for this occurs in En-
gland.

f La Lande's Astronomy, art. 1725,3d edit.

LXXXI. Be-

[ 458 ]

LXXXT. Description of a Manometer, hy means of which
we may ascertain the Changes which take place in the
Elasticity and in the Composition of a determinate Volume
of Air. By M. C. L. Berthollkt*.

jl he appellation of maho/meter has been given to various
instruments whieii have been contrived for ascertaining the
differences of density of the strata of the atmosphere ; for
we cannot determine by the barometer the variations which
depend upon heat and upon the hygrometrical state.

Otto Guerick describes a manometer, which was after-
wards given by Bovle as his own invention ; but neither of
these writers distinguishes its use from that of the barome-
ter. Varignon, Fouehi and Gerstner have since given
various manometers.

These instruments have been generally used for ascertain-
ing the changes of density in the air, by means of the dif-
ference between an empty globe and one full of air, but
sealed hermetically, and put in equilibrium with a metallic
weight; for, when the density of the external air changes,
the globe undergoes a change in its weight, which answers
to that which takes place in a volume of air equal to that
which it occupies, while the metallic weight, which is of a
small volume on!v, remains sensibly the same.

Bouguer employed a different method for comparing the
densities of the atmospheric airf : he used a pendulum
which he made to oscillate at various heights, in order to
judge, from the losses of motion experienced by the pen-
dulum in a given time, of the resistance of the air, and
consequently of its density. His experiments seemed to
him to confirm the opinion which he had been led to form,
viz. that, from the height at which the barometer supports
itself at 16 inches, to that at which it supports itself at 21
inches, there is a constant relation between the densities of
the air and the weights which compress it ; but that this
relation varies from that height down to the level of the sea,
which he attributes to a difference in the elasticity of the
molecules of the air. This error mav proceed from the
difficulty of obtaining results free from uncertainty by means
of the pendulum used by Bouguer, as has been proved by
M. de Saussurej, and from his neglecting to reckon the
effect of the heat, and of the hygrometrical stale of the air.

We might with propriety resort to these methods of

* From Mcmmrci de In SurK'' dTArnttil, torn. i.p. 2F2.

f Man. dt CAcud. des Sciences, 1753. J Joutn, de Physique, 1790.

• ascertain ins

Description of a Manometer* 459

ascertaining the density of the strata of the atmosphere,
if any doubts remained as to the nature of the air, the pro-
portions of its constituent parts, and the law which its di-
latation follows by the elevation of temperature.: but at
present, as we have precise information on these subjects,
and as the uncertainties which may remain on the indica-
tions of the hygrometer are much smaller than those which
ought to result from the methods mentioned ; it is more
expeditious and more certain to adhere to the barometer,
combining its indication with that of the thermometer and
hygrometer.

The case is not the same with the manometer destined
to determine the changes which take place in the elasticity
of a quantity of air contained in a vase. Saussure directed
towards this object the apparatus to which he gave the
name of manometer, and by means of which he made some
most important observations*: it is simply a barometer,
the bulb of which is contained in a bell-glass which is her-
metically closed, and into which we may introduce the sub-
stances which mav afTect the elasticity of the air, by an
aperture in the neck of the bdl-glass, but by establishing,
at that instant, the communication between the internal
and external air.

While the communication with the external air is inter-
rupted, the barometer is insensible to the variations of the
atmosphere, and it undergoes no change in its elevation ex-
cept by the increase or diminution of the elasticity.

This is the manometer, the applications of which I wished
to extend, and which I endeavoured to adapt to the obser-
vation of the phenomena which take place during vegeta-
tion, and generally those which animal and vegetable sub-
stances present, during life or after death, relative to the at-
mosphere with which they are surrounded.

In the first place we perceive that the barometer which
performs the functions of the manometer, indicates. the
quantities of gas which are disengaged or absorbed in a
given time ; and as it is easy to ascertain a change even of
one thousandth part in the height of the barometer, we
may determine a change of one thousandth pari in the
quantity of the contained air, by the absorption or extrica-
tion of a gas.

But in order to make this estimate, there must be a ther-
mometer suspended internally to indicate the same tem-
perature with that of the first observation : or if the tem-

* Essais sur CHygrometrie, p. 109.

peraturt

46o Description of a Manometer.

peraturc be different, we ought to bring back the gas to the
first by calculation.

This calculation requires that we should take in not only
the change of elasticity produced by the temperature, but
also that which flows from the tension of the vapour of the
water which is formed or destroyed; and for the latter pur-
pose we may use the observations of Mr. Dalton.

After having ascertained the variations which have taken
place in the elasticity at different times of the observation,
it is important to be able to determine the chemical changes
which have taken place in the atmosphere of the vegetable
or animal substance, and the nature of the gaseous sub-
stances which may be liberated or absorbed.

This object is attained by means of a stop-cock, above
which we adapt into a reservoir a graduated tube filled
with water : on opening the stop-cock the water falls into
the manometer, and its place is supplied in the tube by an
equal volume of gas : the stop-cock is closed, and we may
carry the tube with the gas which it contains.

We thus obtain a quantity of the gas contained in the
apparatus, every time that we wish to examine it, without
producing any change in the pressure of that which remains,
and in the elevation of the barometer : it is only requisite
to submit the gas which has been extracted to chemical
tests.

We determine the proportion of carbonic acid by the
absorption of lime water, afterwards that of the oxygen by
the hydrogenated sulphuret of lime, according to the
method of M. de Marty* : and lastly, we test the residuum
with oxygenated gas in the eudiometer of Volta, if we
suppose an inflammable gas to exist in it. The remainder
gives the proportion oi' the azote.

In most circumstances carbonic acid is formed, and
more or less of it is dissolved in the water which has been
introduced into the apparatus, according to its quantity,
temperature, and the pressure to which it is submitted.
M. Theodore de Saussure, in order to determine the quan-
tity of carbonic acid which was absorbed in several of his
experiments, contented himself with regarding it as equal
to the volume of water which was in his apparatus. This
determination is not sufficiently rigorous, since the quantity
which is absorbed by the water varies much by the circum-
stances which have been detailed.

The quantity of carbonic acid which has been absorbed

* Journal de Physique, tome lii. dnnalts de Chimie, tome Ixi.

by

Description of a Manometer. 461

by tbe liquid contained in the apparatus, may be determined
by precipitating this acid by lime water, or by water of
barytes, either from the whole or from a part of the liquid :
after that, we introduce the precipitate into a flask, adapt the
tube of a funnel to it, through which we pour a quantity of
dilute sulphuric acid ; and by the loss of weight which takes
place, we ascertain the quantity of carbonic acid which was
dissolved in the liquid, and which is disengaged from the
carbonate. — We may, by the processes which I have indi-
cated, ascertain in a volume of air equal to that of a kilo-
gramme of water, and contained in a manometer which has
this dimension, the change which would be produced by
the volume of one gramme of water ; the production of a
quantity of carbonic acid which does not exceed a centi-
gramme in weight; and a variation in the proportions of the
oxygen and azote which does not exceed a centieme : this
is a precision which would seem to be sufficient for all the
determinations which we would wish to establish.

We have besides the advantage of being able to repeat
and compare the tests at different times, without in-
terrupting the experiment, and to vary several of its cir-
cumstances: 1 have constructed manometers of different
dimensions, in order to apply them to different objects^

Hitherto I have made but a small number of observations
with this instrument, and I have not pursued them with
the care which they require; but my chief object in this
publication is to induce those to employ it who are occupied
with experiments of this nature, and who have more leisure
and perseverance than I have. I shall describe some early
attempts.

M.Theodore de Saussure, to whom we are indebted for
some learned and laborious researches upon vegetation, has
shown, that in most of the cases where we suppose thai the
oxygen gas was absorbed by a vegetable or animal substance,
there is simply formed a combination of the, carbon of
these substances with the oxygen of the atmosphere; that
the volume of the gas did not diminish, except on account
of the absorption of the carbonic acid by water; and that
at the same time water was produced by the combination
of the oxygen and hydrogen which existed in the sub-
stance; so that, although the residue had been deprived of a
part of its carbon by the action of the oxygen £>as, it is
nevertheless found more carbonized afterwards, because it
has been stripped of a greater proportion of hydrogen and
oxygen than of carbon*.

* Reiherches Chimiques sur la rjgjtatidn.

It

462 Description of a Manometer.

It appeared to me to be useful to examine whether these
results, which give the explanation of several transmutations
undergone by animal and vegetable substances, might con-
duce to general consequences, or if they ought to be re-
stricted to a certain class of phenomena.

M.de Saussure had already remarked that the oxvgen gas
was absorbed by the oils, without forming a corresponding
quantity of carbonic acid.

The theory of the solution of indigo by the alkaline bases
which are combined with it, when it is deprived of Oxygen,
and of its precipitation by the oxygen of the atmosphere,
which has been explained in the Elements of the Art of
Dyeing, seemed established on sufficient proofs. Neverthe-
less the analogy, with the facts observed by M. deSaussure,
might lead us to believe that the oxygen of the atmosphere
served to form carbonic acid, with a part of the carbon of
the indigo which had been rendered soluble.

A solution of indigo, made by means of the sulphate of
iron and of lime, limpid and of a fawn-colour, after having
been carefully separaied from the sediment, was introduced
into a manometer of 11 litres 632 capacity: the barometer
was at um,75.74, the thermometer at 12°: two days after-
wards the liquor was completely colourless, and the indigo
was precipitated in dark blue, the thermometer beingat 12,5,
the haromcier had fallen six millimetres.

The filtered liquor was covered while in the air with pel-
Jicles of carbonateof lime, and precipitated abundantly with
oxalate of ammonia : the blue precipitate retained or, a filter
did not effervesce with an acid, and gave with sulphuric
acid a very deep solution of indigo.

Thus we see that the lime preserved its state during: the
precipitation of the indigo, and that carbonic acid is not
formed.

On the other hand, the test of the air contained in the
manometer has shown that it was the oxygen gas which
alone had been absorbed bv the indigo, whose precipitation
it had operated. The experiment repeated a second time
gave similar results: but we bete neglect the calculations
necessary for determining the quantity of the absorption,
because we have not ascertained the weight of the indigo
precipitated. We confine ourselves to the conclusion, that
the quantity of oxygen which disappeared has not been
employed in this case to form carbonic acid ; but that it is
combined with the indigo, to which it lias theieby rendered
its insolubility and colour.

i was anxious to compare the changes which are pro-
duced

Description of a Manometer. 46*3

duced by a colouring substance of a different species, which
was cam peachy wood.

The decoction of campeachy generally obtained has a
blue colour, because we prepare it in copper vessels: jt is
of a fine red when glass or silver vessels are used.

This very clear decoction was cooled in a bottle with a
ground stopper, in order that it might not be altered by the
contact of the air, and placed in the manometer, the ther-
mometer being at 18,5, the barometer Om.7593: four days
afterwards the liquor was turbid, and the temperature being
the same, the interior barometer fell ()m.03. This lowering
continued for two months, and in this time the liquor beeame
very turbid and of a reddish fawn colour: a trifling sedi-
ment was formed, and some crusts.

At the end of the experiment the thermometer was 21 ,25,
the total lowering of the barometer Om.05(), the air of the
manometer wheif referred to its primitive pressure contained
in 100 parts

Carbonic acid , . . 3 oi

Oxygen 6'55

Azote . 89*54

There was at. the end of the operation an increase of tem-
perature of 3° 25, which requires the following correction
in the volume of the gas at the primitive pressure of
0,n.7593.

According to the determinations which M. Gay-Lussac
communicates, the quantity by which a volume of air is di-
lated by 1°, is expressed by the height of the barometer
which represents the tension of this air divided by 266,66,
and becomes on setting out from the degree above zero equal
to the quotient of the tension by this divisor, augmented
by the number of degrees from which we begin to count
the dilatation. In the present case, the height of the baro-
meter at the commencement of the operation = 0'".7593,
the temperature 18°, the column of mercury corresponding
to a dilatation of 1° will therefore be

£ ■»#»» = 0^.00266,
26660+18

and that which is to take off for the dilatation is 3°. 25 =

0,00864. * . .

As to the vapour which ought to be formed on bringing

the numbers of the table of Dalton to the degrees of the

centigrade thermometer, and to the divisions or the metre,

we find that the tension of the vapour being 21°,25,

= Om.018J7 —

and at 18° = cr .01536. The

4 64 Description of a Manometer.

The column of mercury sustained by the elastic vapour
which was produced during the experiment,

= Om.003ll.
The manometer brought to the primitive data has therefore
undergone a decrease

= 0,n.050 •+ 0n,.0O864 + 0n,.00311 =s Om.06)75,

= 0.0813 of the volume of air used in the experiment.

In order to know on what substance the absorption acts,
we must keep an account of the quantity of carbonic acid
which ought to be dissolved; and as we have neglected to
do it by precipitation, as I have indicated, we shall confine
ourselves to regard, with M. de Saussure, this quantity as
equal in volume to the liquid.

The capacity of the manometer being four litres 676, the
volume of the liquid = 0,565, the volume of the air in the
experiment = 4 lit. Ill, the volume of the carbonic acid
dissolved by the liquor = 0 lit. 565y forms the 0,137 : now
on adding up the proportionsof carbonic acid and of oxygen
formed in the air, and supposing that the oxygen gas on
combining with the carbon is replaced by a volume of car-
bonic acid precisely equal to its own, we find that there
is wanting in 100 parts of air 10,54 of oxygen, or the 0,105
of the volume of the air, a quantity which only differs
0,032 from that of the carbonic acid which has been sup-
posed to be dissolved by the liquid. This difference ought
to be neglected, because the volume of the carbonic acid
absorbed ought to be inferior to that of the water, either on
account of the elevation of temperature, or on account of
the diminution of the pressure.

If we compare this result with the preceding indication
of the manometer, we find that there is only 0,02 of dif-
ference, a quantity which may be neglected, chiefly on ac-
count of the inaccurate valuation of the carbonic acid held
in solution.

The phaenomena, therefore, answer perfectly in this cir-
cumstance to the observations of M. de Saussure; the oxy-
gen gas is not absorbed by the decoction of campeachy ; but
the latter changes it into carbonic acid, on giving up car-
bon to it : at the same time, without doubt, water is
formed by the intimate union of the oxygen and hydrogen
which existed in the substance, which thereby becomes
more carbonized; and it is by these effects that we ought to
explain the alterations which it undergoes in its properties.

Then this solution gives only a yellow precipitate with
the nitro-muriate of tin, instead of a bright red precipitate:

an

Description of a Manometer. 46$

an olive-coloured precipitate with the solution of highly
oxidated iron, instead of a blackish blue precipitate: a fawn-
red precipitate with the muriate of copper, instead of a blue
precipitate.

Hence we see that, in the application to the arts, we may
obtain from the campeacby a different colour, according to
the kind of vessel in which we make the decoction : that
the action of the air, at least when it is continued too long,
changes its nature and decomposes it : so that the decoction
kept by the name of campeacby juice may be spoiled, if we
allow it to undergo the action of the air without some pre-
caution.

Results were obtained different from the two foregoing,
when we submitted gall-nuts to the. test of the mano-
meter, with the view of examining what passed in the de-
velopment of the gallic acid : a portion of the oxygen of
the air is transformed into carbonic acid by means of the
carbon of the substance; but another portion also is libe-
rated, the two elements of which it had furnished ; and
lastly, there is a considerable absorption of azote; a cir-
cumstance which requires ulterior observations.

Explanation of the Plate which represents the Manometer,
* and of the Method of using it.

Fig. I and 2. Vertical and horizontal projections of a
cylindrical manometer formed by a vessel A with a large
aperture, the neck of which has a copper rim B. The in-
side of this rim forms a screw for receiving the plate of
copper E, which serves to close the manometer : it rests on a
round pad of leather so arranged that when the lid is screwed
down upon it, the vessel is very closely shut. G,G, but-
tons on which are fixed the notches of the key represented
flat in R, and seen directly in S ; this key serves to keep
the vessel steady, while we turn and fasten the lid with the
other key T ; the square head of which embraces the button
of the same form, which we see at E in the two projections.

a, a j a, three hooks fixed in the lid from which we may
suspend a thermometer, a hygrometer, &c. D, a socket in
which we fix with hard mastic a barometer with a syphon :
as it would be difficult to give it, in this socket, a situation
exactly vertical, and besides, as the inclination of the screw
in the lid may remove it from this position, in order to oive
more precision to its indications, we rest the manometer on
a rim of wood, having three screws in it k, k, k, which we
move until the tube of the barometer be very vertical ; which
we may easily judge by means of the plummet IF, which

Vol. 36. No. 152. Dec. 1810. 2 G is

466 Description of a Manometer*

is to be adjusted successively in two positions which form x
right angle with each other. This plummet is attached to:
a moveable brass scale H, to which we give only 0m.04 to
0m.05 or' extent. This scale embraces, by means of two
rings b b, not shut, the barometrical" tube: it may thus be
placed at any height on the barometer, and preserve the
position- which is given to it. It is used to determine the
quantity which the height of the column of mercury has
varied in the course of an experiment: if this quantity
exceeds the limits of this scale, which is not very probable,,
it may be shifted so as to measure at several times the wholtr
variation observed. The absolute height of the mercury is
taken at the commencement of the experiment on a barometer,
and we fix one of the extremities of the scale H at the sum-
mit of the mercury at this moment. The small branch of
the syphon is furnished with a scale, in order also to ob-
serve the difference of the height of the mercury from the
commencement to the end of the experiment. When the
experiments require it, we give to the tube a length which
exceeds much that of the common barometers, and it may
he augmented sufficiently to indicate a pressure double that
of the atmosphere.

The plate E has at C a stop-cock intended to give .issue
to the air of the apparatus when we wish to examine it ;
and this stop-cock is adjusted in such a manner that we
may repeat these experiments as often as we jud^e it neces-
sary in the course of an experiment, without fearing to
change the nature, or even the state of compression, of the
air of the manometer. For this effect, the stop-cock has
■above Its collet at L (figures 2, 3,4, and 5) two nut-screws,
one internal and one external. On the latter is mounted a
copper salver M, which we fill with distilled water: the
glass tube N, graduated and furnished with a copper socket
at O, is adjusted upon the internal screw, after having been,
also filled with distilled water : the extremity of its screw
is furnished with a round of leather, which we compress.
On opening the stop-cock the water of the tube is dis-
placed by the air, which escapes from the manometer, and
when we perceive that a sufficient quantity has entered into
the tube, we shut the stop-cock. Upon unscrewing the
tube, the volume of the air which has entered generally
changes, and occ upies a smaller or larger space, in proportion
as it underwent in the manometer a pressure weaker or
stronger than that of the atmosphere. But we remove the
tube by plunging the finger into the water of the bason, and
closing with its extremity the orifice of the lube, and we

do

On the Barometer, 467

do not measure the air until after we have determined with
the usual precautions the temperature and pressure to
which it is exposed.

We must only introduce in this manner into the mano-
meter, a liquid, which most commonly does not disturb the
results, and the influence, of which we can always ascertain :
if we were afraid, however, that it would interrupt the ex-
periment, we might receive it into a vessel disposed for this
purpose in the inside of the manometer.

Fig. 3 shows the various pieces just described, ready to
be adjusted : fig. 5 is a section of these same pieces all
adjusted.

We ought to take care, in the construction of this appa-
ratus, to give the hole of the key of the stop-cock a dia-
meter sufficiently large to admit of the easy no win j of the
waAer of the tube, and it ought not to be less than twelve
millimetres. In order that the air contained in this hole
may be in-thesame circumstances with that which occupies
the whole capacity of the manometer, we leave the stop-
cock open during the experiments, as seen in fig. ,1 and 2 ;
we intercept the communication with the external air by
means of a copper stopper O (fig. 1 and 4) which has the
same screw with the mounting of the divided tube, and
which is also furnished with a run of leather. In order to
close it properly, it has at its surface a square cavity which
is seen at p, into which we insert the stalk r of the same
form which is at the extremity of the handle of the key T.
We then only close the stop-cock at the moment when we
wish to extract the air from the manometer.

LXXXU. On the Barometer. By Richard Walker, Esq.

To Mr. Tdloch.

Sir, I^onsidering that I may not have been sufficiently
explicit in my last paper, respecting the effects of the
difference of temperature on the weather, 1 have been in-
duced 'to offer the following remarks on that part of the
subject.

A warm temperature of the air, at any degree of density
of the atmosphere, will retain a greater portion of water in
a state of chemical combination, than a cold temperature of
the air at a similar degree of density of the atmosphere.
Hence we may account for the almost constant dry state
»f the lower stratum of the atmosphere during the sum-

2 G 2 MEK

468 On the Barometer,

mer season, and the almost constant moist stale of the
lower stratum of the atmosphere during the wiNTt r sea-
son ; the air, however, being sometimes sufficiently dense,
as in the clear weather which accompanies a freezing atmo-
sphere, to retain the water in a state of chemical combina-
tion, notwithstanding the diminution of temperature.

The same circumstance accounts likewise for the dif-
ferent states, with respect to moisture and dryness, of the
middle seasons, viz. spring and autumn, accordingly
as these participate in their nature more or less of either of
the former seasons ; observing that, cceteris paribus , there is
more rain and misty weather during autumn than spring,
in consequence of the greater quantity of water which has
been raised into the atmosphere during the summer than

the WINTER SEASON.

All the circumstances I have had occasion to mentibn,
depending upon the greater or less density, and the higher
and lower degrees of temperature of the atmosphere, are
exemplified by the two following familiar experiments:

In the first instance, by means of pumping out of a glass
receiver (containing air apparently dry and perfectly trans-
parent) a certain portion of the air it contains, when the
air being rarefied deposits a certain portion of the water it
originally Contained in chemical combination in a cloudy
vapour, which, upon re-admission of the air, is re-absorbed;
and in the second instance, by abstracting heat from a glass
vessel containing atmospherical air, and again restoring the
heat. The latter circumstance is likewise instanced, natu-
rally, by what commonly happens in the course of a hot
summer's day, particularly when the ground has become
very moist by previous rain ; the vapour ascending visibly in
the morning, disappearing during the middle of 'the day,
and descending visibly again in the evening*.

The variations of temperature in the atmosphere inde-
pendent of those which proceed from the direct influence of
the sun, arise from the conversion of water into vapour,
which produces cold ; and the condensation of vapour into
water, which produces heat. Hence it commonly follows,
that in proportion as the barometer rises, the thermometer
sinks, and vice versa, throughout the year; the direct influ-
ence of the sun in clear weather being abstractedf.

* At Lima, in Peru, it never rains ; the moisture raised in the day time
being restored again at night in the state of mist.

f In summer, during fair wearher, the nights, or rather the mornings be-
fore sun rise, are cold, approaching even to frost.

• Thunder

Royal Society, 409

Thunder frequently follows a considerable duration of
dry hot weather, both these circumstances being favour-
able to the collection and insulation of electric matter.

The extraordinary elevation of the barometer which
sometimes happens, is said to arise from two currents of
air, from opposite directions, meeting and accumulating
over a particular spot ; and the extraordinary depression of
the barometer* from the circumstance of two currents of
air setting out from any particular spot: in either case a
commotion of the air is necessarily produced, whilst the
equilibrium is restoring.

That the atmosphere, as well as the sea, is affected pe-
riodically in a small decree by the attraction of the moon,
is well ascertained ; but it does not appear that the wea-
ther is in the least influenced by any mechanical effect of
the moon.

I was first led to the remark noticed in a former paper,
respecting the difference of the weather during the increase
and during the waneoi the moon, by observing that eclipses
of the moon were much seldomer obscured by a clouded
atmosphere than eclipses of the sun ; and subsequent ob-
servations of a general nature have somewhat confirmed
me in the same opinion.

P. S. I omitted to mention, in my paperou the measure-
ments of heights by the barometer, (Phil. Mag. for Oct.
1610, p. ^ 7 8) that when the lower station in the barometer
is behw what is provided for in Table 2, p". 2*9, as is some-
times the case in different gradations of heights, the most
accurate method will be, first to calculate the whble height,
assuming 30 inches of the barometer for the lower station ;
dnd in like manner calculate the lower portion only, and
then subtract the latter product from the former.

Oxford, Dec 15, 18 1Q. RD. WALKER.

LXXXIII. Proceedings of Learned Societies,

ROYAL SOCIETY.

\Jn Dec. 6th, the reading of Mr. Davy's Bakerian Lecture
was continued, and on the 13th concluded. In this part
of the lecture Mr. Davy detailed a number of experiments,
which he regarded as showing that when any metallic
oxide is converted into the substance improperly called a
muriate, but which is a binary combination or oxymunatic
gas and a metal, the oxygen produced is exactly that which
2 G 3 had

470 Royal Society.

had been absorbed by the metal : and he stated, that the
proportions of oxygen or of oxyinuriatic gas which com-
bine with metals, are always definite; and that when two
proportions combine, the one bears a simple ratio to the
other.

Mr. Davy, inferring from the whole series of facts that
oxymuriatic gas must he considered as a substance as yet
undecompounded, and analogous in many or its properties
to oxygen gas, but having stronger attractions for most in-
flammable bodies, — suggests the necessity of altering its
name; which conveys so false an idea of its nature.

Conceiving it dangerous in the present improving state
of science to adopt any names connected with theoretical
arrangements, which may require alteration as knowledge
advances, — he ventures to suggest for the consideration of
chemical philosophers the name of chlorice, derived from
its screen colour; and he proposes to signify its compounds
by the name of the ba»isv with a termination in inc or awe :
thus hornsilver, improperly called muriate of silver, would
be named argentatte ; muriate of baryies, baryuwe, &c.

On the 13th and 20th, the Croonian Lecture on muscu-
lar motion, by ■ Brodic, Csq. F. K. S. was read. The

subjects introduced in this lecture were less numerous, and
the discussion less varied, than usual on similar occasions;
and very little or no reference was made to muscular
action, the ingenious lecturer confining himself to a simple
detail of the thermo metrical effects on the animal body, in
consequence of dividing the spinal marrow and afterwards
inflating the lungs artificially with a pair of bellows, and
continuing the circulation of the blood under such circum-
stances for nearly two hours. The subjects of operation
were chiefly rabbits: and the author made a great number
of experiments on these animals by dividing the spinal
marrow and suffering them to die in this manner, noticing
their temperature and that of the room at particular periods;
or, after dividing the spinal marrow, inflating the lungs, and
thus keeping up tire circulation for an hour, and even an
hour and a half; noting also the temperature of the heart,
intestines, and rectum, at various times during the experi-
ments. The result of the author's inquiries wa-, that ani-
mal heat dots not appear to be produced, as generally sup-
posed, by the action of the air on the lutfcs, and the cir-
culation of the blood ; as those animals whose lungs were
inflated, and ihe circulation artificially continued, were al-
wavs from one to three or four degrees colder in a certain
time than those whose spinal marrow was divided and s. f-

fered

Royal Society of Edinburgh. 471

Fered to die. Professor Davy suggested to the author, that
the cold air thrown into the lungs (which produced the
usual change in the colour of the blood) might contribute
to this effect; and accordingly an experiment was madr to
obviate such consequence by means of a ligature : when it
appeared, that i:; an hour and forty minutes the body in
which the circulation was artificially continued after di-
v:dmg the spinal marrow, was only one degree colder than
that which died immediately. Mr. B.'s experiments seem to
militate against the doctrine of the vitality of the blood;
but they do little towards illustrating the fact, that tortoises
can live and walk about long alter having been deprived
entirely of the brain, and even part of the spinal marrow.
On the evening of the 20th, part of a letter from Dr.
Parry, of Bath, was read, on certain nervous affections; as
convulsions, tremulous motions, and sudden slartings or
pulsations of what is vulgarly called the life blood ; after
which the society adjourned till January 10.

KOVrAL SOCIETY OF EDINBURGH.

On Monday the 5th of November, the Royal Society of
Edinburgh met for the first time in their new apartments
Sri George-street, when Dr. Thomas Thomson read two
papers, giving the account of the analyses of two new mi-
nerals from Greenland. To one of them he has given the
name of allanite, and to the other sodalite. In the first
he discovered a considerable portion of cerium, and in one
analysis he detected a quantity of a^ metallic oxide per-
fectly new in its properties, for which he proposed the
name of junonium. The other mineral, according to his
investigation, affords 23 percent, of soda and three of mu-
riatic acid. By an analysis of Mr. Ekeberg, the same con-
stituents were yielded in the proportions of 25 per cent, and
six per cent.

At the next meeting on the 19th, a short communica-
tion was read,, respecting a singular water-spout observed
at Ramsgate.

On the 3d inst. a paper by Dr. Brewster was read, being
a new demonstration of the fundamental properties of, the
lever. — Also a communication by Sir George Mackenzie,
Bart, relative to the hot springs of Iceland ; when Sir George
exhibited some beautiful drawings and part of a series of
magnificent specimens from that country, which he pro-
poses to deposit in the cabinet of the Society: and at the
last meeting, on the 1 7th, Sir George began a description
of the minerals of Iceland, when he exhibited specimen
from the district called the Guldbringe Syssel.

LXXXIV. In-

[ 472 ]
LXXXTV. Intelligence and Miscellaneous Articles,

DE LUC'S ELECTRIC COLUMN.

W e have now to inform our readers, that the small pair of
bells connected with the electric column invented by Mr. de
Luc, which we have frequently noticed, were perceived to
cease ringing for about ten minutes on the 4th of September;
then (the apparatus remaining untouched) to begin again to
ring by intervals, stopping perhaps half a second or more
at a time : they stopped for several days after this, and be-
gan again, and at other times for hours ; and on the 18th
of November they were removed from the column, not
having been heard that morning.

1 3i h December, 1810.

Till the appearance of Dr. Adams's last edition of Mor-
bid Poison, it was universally believed that the unhappy
subjects of the Arabian leprosy are peculiarly salacious;
an opinion as old as Aretaeus, copied by most succeeding
authors and contradicted by none. Dr. Adams, from ac-
tual observation, has proved the fallacy of this opinion.
A melancholy case is now in St. Bartholomew's Hospital ;
a native of the Portuguese Brazils, about 30 years of age,
without beard, and with all the other peculiarities remarked
by the above accurate writer.

LECTURES.

Mr. Taunton's Spring Course of Lectures on Anatomy,
Physiology, Pathology, and Surgery, will commence on
Saturday, January 19th, 1811, at Eight o'clock in the
Evening precisely, and will be continued every Tuesday,
Thursday, and Saturday, at the same hour, at the Theatre
of Anatomy, Greville-Street, Hatton Garden.

Dr. Clutterbuck will begin his Spring Course of Lec-
tures on the Theory and Practice of Physic, Materia Medica,
and Chemistry, on Monday January 21st, at Ten o'clock in
the Morning : viz. Theory and Practice, on Mondays, Wed-
nesdays, and Fridays ; and the Materia Medica and Che-
mistry, on Tuesdays, Thursdays, and Saturdays. Further
particulars maybe had at No. 1, Crescent, New Bridge-
Street.

Dr. Adams's Course of Lectures on the Institutes and
Practice of Medicine, will commence on Thursday the 10th
Instant, at his House in Hatton Garden, precisely at Ten
o'clock.

METEORO-

Meteorology.

47*

METEOROLOGICAL TABLE,

Bir Mr. Carey, of the Strand,
For December 1810.

Days of
Month.

Th

ermom

c
9

2

eter.

Height of

tnc Baiom.
Inches.

DcurcesofDry-
nessbv Leslie's
Hygrometer.

Weather.

Nov. 27

41

47°

42°

29*20

12

Fair

28

40

46

39

•01

21

Fair

2<J

36

43

37

26*98

0

Rain

30

35

42

34

29*25

17

Fair

Dec. 1

34

38

36

•50

12

Fair ,

2

32

36

31

•90

10

Fair

3

3(>

37

40

•65

0

Rain

4

42

44

44

•90

8

Fair

5

45

49

47

. '89

10

Fair

6

47

50

44

•46

0

Rain *

7

44

47

36

•30

6

Fair

8

37

42

30

•61

0

Rain

9

29

35

31

•87

10

Fair

10

35

40

36

•23

0

Rain

U

36

38

30

•80

5

Fair

12

35

46

42

•30

0

Rain

13

46

52

47

•85

10

Fair

14
15

48
40

48
46

43
36

•50
•86

5
15

Stormy
Fair

16

37

43

35

30*30

10

Cloudy

17

41

49

47

•08

7

Cloudy

18

48

46

45

29*40

0

Rain

19

41

40

36

•51

9

Fair

20

37

44

43

•62

0

Rain ,

21

43

46

42

•38

10

Fair

22

41

46

52

•60

9

Cloudy

23

52

47

43

•42

8

Fair

24

42

43

41

•45

4

Rain

25
26

49

44 J

49

47

46

•05

1

25

Stormy, and in the
evening many
vivid flashes of
lightning.

Fair

N

.B. Th

e Bare

meter'

i height is tal

V.

cen atone

o'clock.

C 474 ]

INDEX to VOL. XXXVI.

A CETATE of potash. To prepare
colourless, 53

Acid, muriatic, the base of, 71,. 152,
1)515; Oxynwriatic, a simple sub-
stance, 152, 352, S03, 404 ; corn^
binationsof,404 ; Mucous, to pro-
cure pure, 191 ; prussic and prus-
sous, Porrett on, ' 196

Alumine- Constituents of, 88

Amalgams of the new metals, 86 ;
mercury and silver, 143

Ammonia. Davy on, 17; singular
compound of, 71, 152, 354, 407;
constituents of, 89; perhaps a deu-
toxideof ammonium, 91

Analysis of meteoric stone, 32; of a
supposed new earth, 77; of British
and foreign salt, 106 ; of Atropa
belladonna, 144; ofscammony, of
socotrine and hepatic aloes, 22 1, 225
Animal heat, new ideas on, 470

Arbor Diana: Vitalison, 143

Artillery, proper charges for, 333
Astronomic refraction. Improvements
in, 340, 446

Atropa "belladonna analysed, 143

Attraction, sol-lunar influence of, on
clouds, 58

Bakerian lecture for 1 809, Davy's, 1 7
Balls, On penetration of, wuh dif-
ferent charges, 325
' Barometer. Sir H. CEnglefield's, 241 ;
prognostics of, 275, 376
Barraud's mercurial pendulum, 83
Baryl.es. Constituents of, • 88
Berrard on muriate of tin, 205
Bernoidly on acetate of potash, .03
Bethlcm hospital. Subscription for
rebuilding, 234
Bogs in Ireland. Parliamentary re-
port on, 361,487
Braconnol's analysis of aloes, 224
Calculi, urinary. Remedy fo'r 8
Calomel. Cheap process for prepar-
ing, 281 ; to purify, 283
Camp telegraph, Knight's, 321
Carey s meteorological tables, 80, 160,
240, 320, 400,473
Chenevix on mineralogical systems
286, 878,413
City, ancient, discovered, 78
Coffee grown in France, 316
, Cold, Leslie's artificial, 76
Combustion, not caused exclusively
by oxygen, '557

Comets. New theory on orbits of'

253
Compensation Pendulums. On, 81
Congreve's roikcls, a prize question,

232
Coromandel. Land winds of, 243
Ccw covered with horns, 70

Crane on orbits of comets, 253

Craniognosy. A work on, 74,77
Crystallography. Haiiy on, 64,121
Ci/raduu's process for obtaining so-
dium and potassium, 282
Cuthbertson on increasing the charge
of electric jars, 2.59
Cystic o.ride, a species of urinary cal-
culus, 70

Dalian, on proportion of oxygen in
protoxides and neutral salts, 88

I? Ariel's notes on Gold, 153

Davy's Bakerian lecture for 1809 —
Fxper. on nitrogen, ammonia, and
the amalgam from ammonia, 17;
on the metals of the earths, 85 »
on muriatic and oxymuriatic acid,
70, 152, 352; his experiments re-
peated at Moscow, 73; conside-
rations of theory, 90; recantation
of French chemists respecting his
new metals, 153; new experiments
On oxymuriatic gas, 392, 404

De thut on the poison of the Bohan
vp'.is and Anted, 70

De Luc's geological travels, 3 ; elec-
trical column, 75, 317,472

Did'uc on sugar of apples, 218

Dyeing. Hints on, 433

Earthquake at the Azores, 397

Earth screw. Salmon's, 257

Ecliptic. Obliquity of, 424

Electricity, a prize question, 232
Electrical jars. Charging capacity of,
increased, 259

Eugle/ield's (Sir K. C.) mountain ba-
rometer, 241 ; account of a thun-
der-storm, 349
Emu* on astronomic refraction, 340
44G
Extractive principle, a prize question,

154
Fubbroni on purity of gold, 182

Farcy's musical theorems, 39; re-
marks on Michel's list of British
strata, »ol -S+tf

Farcy (//I) On bogs in Ireland, .443

INDEX.

475

Firminger on obliquity of ecliptic,

424
Flesh. Loss by cooking, 142

trench National Institute, 153

Fremy on acetat of potash, 55

Gales of besieged places, best way of

forcing, 333,334

Geoghegan's mode of treating rupture,

2:57
Geological travels. DeLuc's,3'/ac/5,445
Gold. Native coined, modes of pu-
rifying, 153
Gum-resins Exper. on, 18.5
Harris on 6ol-lunar influence on
clouds, 58
IJassenfralz on fight, 271
Hauy's Crystallography 64, 121 ;
system examined, 296
Jlealy on cupping, 131
Heights, to measure, by barometer,

277
Hemp. A new species of, 157

Henry's analysis of British and fo-
reign salt, 106,171
Home on bite of rattle-snake, 209
Houses. To build of earth, 263

Imperial society of Moscow, 7 1

indigo. Experiments on, 462

Ireland. On the bogs of, 361, 437
KnighCs telegraph, 3.21

Language, universal, a prize question,

233
Laplace on obliquity of ecliptic, 424
Learned societies, 70, 152, 392, 469
Lectures, 157, 237, 317,472

Lennons proposed iron tunnel, - 34
Leslie's artificial cold, 76

Letsom on the use of oil of turpen-
tine to expel the tape-worm, 306,
335
Light. Experiments on, 27 1

Lime, effect* of, on healthy urine, 15 ;
constituents of, 88

Lunar injiuencc on clouds, 58

Magnesia effect of, in preventing the
formation of urinary calculi, 8 ;
on healthy urine, 14; constituents
of, 88; native, 3*6

Mammoth. Notice respecting, 74
Manometer described, 465

Marrat on prime and ultimate ratios,

186
Mastich. Exper. on, 185

Mathematics. Discovery in, 236

Mercurial pendulum, performance of

83

Meteoric stones. Analysis of, 32;

shower of, 316

Meteorology, 58, 74, 80, 160, 240, 320,

393, 400, 473

MicheFs list of British strata, 102

Mineralogical systems. On, 286, 378V

413
Moore on charges for ships' guns, 325
Muriatic acid gas. Davy's ideas on, 91
Muriate of mercury, sublimed. To
prepare, 281 ; to purify, 283

Muriate of soda.' Henry on, 106,171
Muriate of tin. On preparing, 20S
Muriatic acid. Composition of, 71,
152, 353
Musical theorems, 39, 374; instru-
ments, on tuning, 163, 167; time*
220, 435
National vaccine establishment. In-
structions from, 303
Natural philosophy, a priee question,

233

Neutral salts, proportion of acid in, 83

New books, 15, 156, 1 59, 236

Nismes, restoration of antier.t, 234

Nitrogen. Davy on, 17 ; not a metal

in the form of gas, 91 ; perhaps a

protoxide of ammonium ; basis of

muriatic acid, 153

Nomenclature, New 470

Numbers, propos«d improvement i»

noting, 397

Obliquity of ecliptic. Diminution of,

424
Oil, olive, to purify, 372

Oil of turpentine. A cure for tape-
worm, 306, 335
Oiii-Hixum, composed of gum and re-
sin, 185
Orbits of comets. New theory of, 253
Oxygen gas. On supposed absorption
of, by vegetables, 46 i ; by indigo,
462; with Campeachy wood, 463
Oxy muriatic acid, a simple substance,
155*, 353 ; combinations of, 353,
404, 470
Park?, MtiJigo. Tidings of, 39S
Patents, 78, 159, 238, 318, 399
Pendulums, compensation. On, 81
Phcenotnriutn, singular, at sea, 395
Phosphorus. Davy's exper. on, 352;
singular compound of, 71, 152,
354, 407
PUot'Jtsk, 156
Potash. Exper on, 393
Polonium. Curadau's process for
obtaining, 283
Prixe questions, 75, 154,232
Protoxides. Proportion of oxygen in,

88
Psychology, a prize question, 23$
Pus. Pearson on, 71, 161

Ratofcite, a new earthy substance, 73
Ratios, prime and ultimate. On, 18Q
Rattlesnake. Effects of bite of, 209
Refraction, astronomic. Improve-
ments made in, S4Q, 446

476

INDEX.

Resijis. Exper. on, 185 ; redden turn-
sole, 186

Roxburgh on land winds of Coroman-
del, 243

Royal Society, London, 70, 152, 392
469

Royal Society, Edinburgh, 471

Rupture. New mode of treating, 237

Salmon's thief- catcher, 256; method
of building houses of earth, 263
Salt, (muriate of soda) Henry on,
106, 171
Sandarach, a pure resin, 185

Screw to secure posts, &c ax the earth,

257
Serpents fed by a child, 315

Ships* guns. Charges for, 328

Singular compound, 71, 152, 354, 407
Smeaton's papers, preparing for the
press, * 102

Smyth's system of tuning. On, 1 65, 435
Soap-works. Cause of explosions in,

304
Societies, learned, 70, 152, 392, 4(>9
S<;*ia, effects of, on healthy urine, IS;
exper. on, 393

Sodium. Curadau's process for ob-
taining, 283; Davy's new process
for obtaining, 393

Solar injlaence on clouds, 58

Strata. The principal British, 102
Stroniites. Constituents of, 88

Sugar from apples, 218

Sulphur. Davy's exper. on, 352

Surgical cases, 151, 230

Surgery. Hints to improve, 401
Tape-K"»m, expelled by oil of tur-
pentine, J306, 335
Taunton's iurgical

Taylor's new engine, to be worked
either by water or by steam, 394
TcUgrafsh, Knight's, 321

Thermometer. On Mr. E. Walker's
scale, 16; Mr. R. Walker's metal-
lic for high temperatures, 119
Thief-taker, a mechanical, 256
Thunder-storm. Violent, 349
Toridci/T on decomposing water, 303
Travels in Siberia, 72 ; in Russia, 72
Tiomsduijf' on aloes, 221
' Tunnel under the Thames proposed
to be made of iron, 34.

FatciuatUm. Dublin report, 96 ; na-
tional establishment instructions,
308

Fauquflin's analysis of Atropa bella-
donna, 143

Fegetables. On supposed absorption
of oxygen gas by, 46 1

Vesuvius. Eruption of 313

Upas. Exper. on, 70

Urinary calculi. Remedy for, 8

Walker's, (R.) Thermometer for high
temperatures, 119; on prognostics
by the barometer, 275, 376, 467
Walker, (E.) on pendulums, 81 ; on
purifying olive oil, 372

Warden's analysis of meteoric stone,32
Watches. Oil for pivots of, 372

Water. Decomposition of by char-
coal 303
Weather. To foretell, 275, 376
Wernerian Society, 233
Werner's system. examined 286, 378
Winds, land, of Coromandel, 243
Winsfield's method of increasing the

charge of electric jars,
Wollaslon on cystic oxide,

259
70

END OF THE THIRTF-SIXTH VOLUME.

Printed by Richard Taylor and Co., Shoe Lane, Lmdon.

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