sMss:

JOURNAL

OF

CHEMISTRY,

AND

THE ARTS,

VOL. XVIII.

P

3IIlusttatei3 toitfi OBngtatimgs.

BY WILLIAM NICHOLSON.

LONDON:

yaiNTED BY W. STRATFORD, CROWN COURT, TEMPLE BAR j FOR

THE AUTHOR,

AND SOLD BY

J.STRATFORD, No. Il2, Holborn-Hill.
1807.

PREFACE.

HE Authors of Original Papers and Communications
in the present Volume are^ Aletes; William Ramsey;
John Gough^ Esq.; Hydrophilus; James Parkinson;
11. B. ; Tyro; Apsophus; Sir George Cayley, Bart,;
Mr. Robert Harrup; O. N.; Thomas Young, M. I>.
F. R. S.

Of Foreign Works^ Henry Braconnot; Mr. West-
rumb; M. Berthollct, Jun.; M. Gueniveau; Mr. Ami
Argand; M. Regnier; P. F. G. Boullay; M. D'Arcet;
Dr. Henry; F. Link; M. Placidus Heinrich; M, Zacharj
Nordmark; M. Olbers; M. Gehlen; M. Berzelius;
M. Eckeberg; M. Allaire; Baron von Zois; M. Guyton;
n. A. Vagel; Bouillon Lagrange; M. Haquet; J. C. De-
lametherie; M. Eiot; C. A. Prieur; M. Descotils; M.
Thenard; *T. F. Daiibuisson; Dr. Veau-de-Launay; John
Ma^ltz; General Mcrriweather; Dr. Baoonio; Professor
Proust; F. Berger, M. D,; L. Juririe; M. L Fremy;
M, Du Pontde Nemours; M. deVincens; C. R. Jousselin;
Mr. J. M. Haussmann; Philip Antony Steinacher; Mr.
J. B. TrommsdorlF; Mr. Klaproth,

And of British Memoirs abridged or extracted, John
Bostock, M D.; Mr. Argand; Thomas Young, M. D. ;
John Maher, F. H. S.; Sir Joseph Banks, Bart. K. B.
P. R. S.; Thomas Andrew Knight, Esq. F.R. S.; Mr.
R. Sahnon; Mr. John Prior; Rev. James Hall; Humphry
Davy, Esq. F.R. S. M. R.LA.; Mr. Benjamin Stott.

The Engravings consist of L Capillary Action of Fluids,
by Aletes; 2. Boullay^s Apparatus for Phosphoric Ether;
3. Mr, Gough's Chamber Barometer; 4. The Proteus Aii-
guirjtis; 5, Mr. Maher's Blanching Pot ; 6. Three Repre-
sent ationSj^ of the Sacro Catino; ?. Universal Tide Table;
8. General Table of Lunations; 9. Mr. R. Salmon's Geo-
metrical Quadrant and Staff; 10. Mr. Jolln Prior's Larura
for Pocket Watches; II. Structure of Covered Ways; 12.
Sir George Cayley's Expansion Air Engine; 13. Mr. Stott's
Engine for splitting Sheep Skins.

TABl/E

TABLE OF CONTENTS

TO THIS EIGHTEENTH VOLUME.

SEPTEMBER, 1807.

JEngravings of the following Objects : L.CapilJary Actions of Fluids. 2. Ar-
i^and's Valve Siphon: 3. Regnier's Powder Prover: 4. BouUay's Apparatus
for Phosphoric Ether,

I. Remarks oiisomi; Difficulties which occur in the Investigation of the Capil-
lary Action of Fluids - - - ' - Page 1

II. On the Solubility of some of the Earths by Means of Sugar. By Mr. Wil-
liam Ramsay - - . _ . w q

HI. Inquiries concerning the assimilating Power in Vegetables f by Mr. Henry
Braconnot : read at the Academical Society of Sciences of Nanci, November
22d, 1806 - - - - - - 15

rV. On Vegetable Mucilages. By John Bostock, M. D. of Liverpool 28

y. Observatiohs on Sulphurous Mineral Waters. By !Mr. Westrumb 40

VI. Report on a Memoir of Mr. Berthollet, Jun. entitled : Inquiries concerning
•the reciprocal Action of Sulphur and Charcoal. BylVIessrs. Fourcroy, Dey-
f euxj andVauquelin - - - - "- 43

VII. Account of the Metallurgic Treatment of Pyritous Copper at the Mines
of Chessy and Sainbel, in theDepartment of the Rhone. By Mr. Gueniveau

• ■ « 51

Vni. Description of the Valve Siphon of the late Mr. Ami Argand, Inventor
of the Lamps with a Double Current of Air - - CI

JX. Descif[)tion of anew Instrument for proving the Strength of Gunpowder.

• By Mr. Regnier, Keeper of the central Depot of Artillery^ - 62

X. Mode of making Phosphoric Ether by Means of a peculiar Apparatus. By
•Mr. P. F. G. 'JonlUv, Apothecarv, at Paris. Read before the First Class of

theJnstitulje, Maiciii"he23d, ISO?' - , . - - 63

XI. Remarks on the Decomposition of Acetate of Barytes by Means of Soda.
By Mr. D'Arcet - - - - *^ - 6(5

XII. Observations on the preceding Article. By M, L. B. Guytcn, one of the
' Authors of the Annales de Chemie - " - . . 70

Scientific News. — Imperial Academy of Sciences, ib — ^Discovery of the New
Planet by Mr. Olbers, 75~Fluoric Acid in Teeth and Bones, ib— Sulphur

- inflamed by Oxide of Lead, 77 — YttHa and Cerium, ib— New Process for
' scowering .Wool, 78— Argand's Lamps, ib— Dr. Young's Lectures on Na-
tural Philosophy and the xMechanical Arts, 79— Mr, Accum's Lectures on

• Ckemistry and Mineralogy, 80

OCTOBER,

CONTENTS. , r

OCTOBER, 1807.

Engravings of the following Objects: 1. Mr. Gough's correct Chamber Barom-
i eter : 2.'The Proteus Anguinus : 3 . Tlnee Representations of the Sacro Catino :

4. Mr. Maher's Blanching Pot: 5. Universal Tide Table: 6. General Table

of Lunations.
A Duplicate of the Plate of the Tide and Lunar Tables is given, that it may be cut

out and put together, either as it is, or mounted on pasteboard, vrithout rendering

the Work imperfect.

I. Description of a correct Chamber Barometer. In a Letter from Jolm Gough,
Esq. , . - - - - Page 181

IL, Observations on the Phytolacca, or American Pokeweed. By Mr. H. Bra-
connot. Member of the Academy of Sciences, &c. at Nanci - 185

III. A Memoir on the Proteus Anguinus. By Baron von Zois - f'gi

IV. Account of the Antique Vessel, that was preserved at Genoa under the Name
of Sacro Catino, and reputed to be an Emerald; with the Report made of it
to the French Institute, August 4, 1806. ByMr. Guyton - 19t

V. On the Cultivation of the'Crambe Maritima of Linnens, or Sea Kale. By-
Mr. John Maher, F.H. S. - - ' - loa

VI. On Grease, and some Medicinal Compounds, of which it is the Basis. By
H. A. Vogel, Chemical Operator in the Pharmaceutic School at Paris.—
Abridged by Bouillon Lagrange _ - - - lp5

VII. Extract of a Memoir of Mr. Haquet, on the Formation of Flint 114
VII f. Of the Oxidation of the Solder of Leaden Vessels used in \\ ash-houses.

By J. C. Delametherie - . - - - 115

IX. Example of a Calculation in the Doctrine of Chances ; a Tide Table ; and

Remarks on the breaking of Waves. In a Letter from a Correspondent 1 1 S
yi. Nondescript Encrinus, in Mr. Donovan's Museum - li'l

XL Inquiry respecting a Fact not hitherto noticed in the Way of Discussion, hi

a Letter from R. B. - - - *- v - ]22

XII. Questions on some Appearances of the Electric Spark. By a Correspond-
ent ------ 123

XIII. Extract of a Letter from Mr. Biot to Mr. Berthollet - ibid.

XIV. Summary Considerations on the Prismatic Colours of Bodies reduced to
thin PeUicles ; with an Explanation of the Colours of Annealed ' Steel, and
those of the Peacock's Feathers. A Fragment of a Work on Colours. By
C. A. Pricur - - - - - 128

XV. Account of a Fulminating Compound of Silver, of a ^^'hite Colour nid
Crystalline Appearance. By Mr. Descotils ' - - 140

XVI. Mv^moir on the Means of forming a Judgment of the Quality of Glass,
particularly Window Glass, and distinguishing such as is liable to Alteration.
By Mr. Guyton. Bead at the General Meeting of the Society of Encourage-
ment, March the 11th, 1807 - - - - 142

XVH. Report on a Paper on Nitrous Ether, read to the Institute the 4th of Au-
gust, 1806, by Mr. Thenord, Professor in the College of France. By Messrs.
^ Guyton, Vauquelin, and Berthollet - - - 144

XVIII. Observations on Subterranean Heat, made in the Mines of PouUacucn
and Huelgoat in Brittany. ByJ. F. Daui)uisson - - 148

XIX. Letter from Dr. Veau-de-Launay to J. C. Delametherie on the Production
of oxigenized Muriatic Acid by the Galvanic Pile - - 155

XX. Scientific News. — 'New Bavarian Academy of Sciences, ib.— Boyal Li-
brary at Munich, 157, — Collection of ]*aintings, ib. — Royal Academy of His-
tory and Antiquities at Naples, ib. — Meclianical Imitation of various W^ind
Instnnnents and others, ib. — Intended Tour in the East, 158. — Ancient Busts
made by American Indians, ib. — Extensive Bidgesof Shells in America, ib.
— Vegetable Galvanic Pile, 159 — Mathematical Kepository, ib. — Mr. Ac-
cum's new Mineralogical Work, 160. — Lectures on Surgery, and on Physi-
ology, ib. — Medical and Chemical Lectures, St. George's Hospital, and
George Street, Hanover Square, ib,

NOVEMBER.

IV. Some
Climate

^\ ^ CONTENTS.

NOVEMBER, 1807.

■Enirravmgs of the following Objects: 1. Mr. Salmon's Geometrical Quadrant
and Staff: 2. Mr. John Prior's Larum for Pocket Watches.

L Facts towards a History of Pit-coal. By Professor Proust. - 161

11. Abstract of a Memoir on Muriatic Ether, read at the Institute February the
nth, 1807, by Mr. Thenar d ----- 17<5

in. Abstract of a Memoir on the Products that result from the Action of Metallic
Muriates, oxigenized iMuriatic Acid, ajid Acetic Acid, on Alcohol. By Mr.
Tbenard . • - - - - 183

Hints respectinjT the proper Mode of inuring Tender Plants to our
. By the Right Hon. Sir Joseph Banks, liart. K. B. P. R. S. &c. 186

V. Observations on the MetlM>d of producing new and early Fruits. By Thomas
Andrew Knight, Esq. F.R.S. &c. . - - 189

Vf. Memoir on the Desulphuration of Metals. By Mr. Gueniveau, Engineer
of Mines - - - - - - 197

VII. Heights of various Places d^ermrned by tlie Barometer, in the Course of
seveial Tours through France, Switzerland/ and Italy. By F. Berger, M. D.
of Geneva - - ■* - - - 210

VI n. A new Method oi classing the Hymenopterous and Dipterous Insects.
By L, Jurine, Correspondent of tiie Institute, Professor of Anatomy, &c. 218

|X Description and Manner of using Mr. Robert Sahuon's Geometrical Plot-
ting Quadrant, Level, and Calculator, for the IJse of Navigation and Land-
Surveying; ascertaining inaccessible Distances, and demonstrating and deteB-
ipining various Problems in Geou^etry and 1 rigonomctry - 21^

X. Description of a Larum applicable to any Pocket Watch, By Mr. John
Prior, of Nesslicld, nearSkipton, in Craven' - - 22S

Xf. Observations on .the Combination of fixed Oils wilh the Oxides of Lead,
and with Alkalis. By Mr. F. Fremy, Apothecary, of Versailles 231

;^Il. Account of a pretended pure native Magnesia ^ - 23S

XIII. Some remarkable Occurrences in Natural History, From the Rev. James
Hall's Travels in.Scotland - - ^ - 23Q

XIV, Facts respecting Indian Corn. By Professor Proust ^ 233

DECEMBER,

CONTENTS. Yii

DECEMBER 1807.

"Engravings of the following Objeccts : 1. On the Construction of GovcFod Wajs^t
2. Sir John Caviey's Expansion Air Engine.

I, Remarks on the Structure of- covered Ways, independent of the Pririciblef of
the Arch in Equilibrium, and on the best Forms for Arches in Buildings,
From a Correspondent (Apsophus) - - - - 241

IE Additional Remarks on the capillary Actions of Fluids. By Aletes. 250^

III. On a Kind of DeatJi, that may be presumed to be only appaj-ent. By Mr.
' Du Pont de Nemours. Read at the First Class of the Institute, October 28,

1806 - - - « ... . .2H^

IV. Description of an Engine for affording Mechanical Power from Air ex-,
panded by Heat. By Sir George Cayley, Bart. - - 26<y

V. A Letter from Mr. Robert Harrup to the Editor, on the Diseases of Wheat

2Q2f

VI. Description of a simple and convenient portable Electrometer for Mineral-
ogists. In a Letter from a Correspondent . - - 27 Q-

VII. A Method of sowing Clover^ and a new Plan for a Rotation of Crops.
By Mr. de Vincens, of Th<»de, near Clermont - - 271

VIII. A Memoir on Roman Alum, compared with different Kinds manufac-
tured in France. By Messrs. Thenard and Roard. Abridged by Mr. Bouil*
lon-Lagrange . - . . _ 275

IX. Essays on the Improvement of Pottery in general, or the Art of making, at
the least Expense. Vessels for eveiy Use, more handsome, strong, and whole-
some, without ei7iploying Lead or Tin, in the Composition of the Coatings
Enamel, or Glaze. By Mr. C. R. Jousselin, Manufacturer at Nevers. An
Abstract by Mr. Guyton - - - - 251.

K. Process for proving the Quality of a Glaze of Earthen Ware - 294

XI. Heights of various Places in France, &c. By Dr. Berger - 295

XII. Transformation of Mr. Dubuat's Hydraulic Theorem. By Thomas
Young, M. D. F. R. S. - - - - 309

XIII. Observations on the Theory of Ear Trumpets, with a View to their Im-
provement. ByJohnGough, Esq. - - - - 310

XIV. Report made to the Mathematical and Physical Class of the Institute, on
a Memoir of Mr. Descotils, relative to Iron Spar. By Messrs. Berthollet,
Lelievre, andVauquelin - - - • 315

Scientific News * * • % » 32d

SUPPLEMENT

tlit CONTENTS.

SUPPLEMENT TO VOL. XVIIL

Engraving of the following Object : Mr. Stotf s Engine for splitting Sheep Skins.

I. On some Chemical Agencies of Electricity. By Humphry Davy, Esq.
F. R. S» M. R. L A. Read November 20, 1806 - - Page 321

H. Extract of a Letter from Mr. J. M. Haussmann to Mr. Berthollet 339.'

». .'.1 /•-'■''•' > . • '. ' ' ■ '

HI. Observations on the Distilled Water of common Borage. By Philip Antony

Steinacher, Member of the Pharmacuetic Society of Paris - 343

IV. A Memoir on Acetic Acid . By Mr. J. B. Trommsdorff - 345

y. Account of an Engine for splitting Sheep Skins. By Mr. Benjamin Stott, of
Bermondsey Street - - ^ _ 34 g

^. A Memoir on Sulphuric Acid. By Mr. Klaproth : read at the Philomathic
Society of Berlin ~ - - - - , 349;

Scientific News. — A Classification of Vegetables, and Plan of a new Method
formed on that of Toiirnefort, according to which the Plants of the Garden
of the private School of Pharmacy at Paris are arranged. By D. L. Guyart,
Assistant Professor of E0tany at the School, &:c. - - 351

Lid - ^9T/i>iiaJ[

«i^ 2. yi//ii/f!!flll0

h\/n'{^n^ r/ulcK).f<Hti'n^,YolJ]^UI.riJl.p.

A

JOURNAL.

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

SEPTEMBER, IS07.

ARTICLE I.

Remarks on some Difficulties which oceur in the Investigation
of the Capillary Actions of Fluids,

To Mr. NICHOLSON.
SIR,

JL HE capillary actions of liquids have lately been mi- Capillary ac-
imtely investigated, both in this country and in France, and poryet corn-
several essays on the subje6t have been inserted in your pletely investi-
Journal: but there appears to me to be still some deficiency ^^^^ '
in all the modes of demonstration which have been employ-
ed. Mr. Laplace's first method leads to erroneous conclu- Laplace defec*
sions, respecting the angle of contact of a solid and a fluid : *^^®*
his second is less exceptionable, but it is still defective in
omitting the consideration of the force of repulsion ; for it
cannot be denied, that this force is equally indispensable p f i-
with that of cohesion to the existence of all material bodies sion necessary
in the state of solids or of hquids; and every theory of the tobeconsid^-
mutual actions of the particles of such bodies, which does !

not comprehend the consideration of both these forces, must
necessarily be imperfect. Dr. T. Young's reasoning, al- Dr. T. Young,
though built on more probable suppositions respecting the
mutual actions of the particles, does not seem to be mathe-
VoL. XVIII— Sept. 1807» B matically

2 ON CAPILLARY ACTION*

. itiatically conclusive, so fat as it relates to the pliysical foun-
dation of the general law of an equal tension of the surface
of any given liquid.

In the first place it appears, that Mr. Laplace's conclu-
sion respecting the attraction, which he supposes to be Ex-
erted by a liquid, terminated by a plane surface, on any
imaginary column within it, may be confuted on every sup-
position that can be formed, respecting the nature of the
Force that forces concerned. For the force which tends to draw every

tends to draw guch column downwards into the liquid, can only be derived,

a column of _ , _. _ , . , , . . _

fluid down- irom the actions ot the neighbourmg columns, and must

ward, tends to therefore tend in an equal deoree to elevate them : so that
draw the ntigh- , n ^ i t - ^ i n

bouring co- ^"^ parts ot each column which are nearest to the surface

lumns upward, are urged downwards, and the remoter parts upwards, by
equal forces ; and the result is merely a general attraction
of the whole'stratum for the stratum next below, which of
Counteracted course must be completely counteracted by the (repulsive
sive force. force, whatever its nature may be. Thus the portion A (PI. I,
Fig. 1) is urged downwards by the attractions of the por-
tions B and C, while D is urged upwards by those of E
and F ; and in the same manner D is urged downwards by
G and II, while I is urged upwards by B and C. And
thus, by continually adding to the substance any number of
successive strata, we shall still find, that the general effect

Thus equih- ^f ^^^ whole body on the column A I will retain it in equi-
biium main- ,., , , i xi i i t • i

"tained to any bbnum, whatever may be the depth. It is true, that ac-

depth. cording to Mr. Laplace's own principles, the attraction of

Laplace's prin- any limited number of strata, on a column passing through

Jteabfe "o^so-^ them, must disappear, the force of the lower surface, which

lids, or solids he supposes to be directed upwards, -counteracting that of

an uids. the upper in a contrary direction; but this consideration,

although it may lead to a correct result with respect to the

actions of fluids only, is not applicable to those of solids,

or to the mutual actions of solids and fluids.

Hisdctermifta- In the second place, Mr. Laplace's determination of the

tion of the at- attractive powers of a wedt^e of any kind, as proportional to

traction of a. '^ -iiit^xti

wedge leads to its chord, must necessarily lead, as Ur. Young has already

erroneous piin- observed, to a proposition respecting the equilibrium of the

surface of a fluid with a so.lid, which Mr. Laplace will

not justify, and which he has silently abandoned ; that is,

that

ON CAPILLARY ACTION. $

that no antjular termination, of a fluid in contact with a so- Angular ter-
. 1 .1 J '^L r u.^ 1- 1 I A rnination of a

lid can remain at rest, unless the density ot the solid ue (:i^,j^j-,j^q^j^j,j

precisely half that of the fluid. Thus if A B (Fig. 2) be with a golid
^ „ ,. r. . 1 ' 1 • 1 • ^ 1 -^ i- 1 cannot Vemaiii

the surliice of a fluid retained in a horizontal situation by ^t rest, unless

the vortical force C D, resulting from the joint actions C E the density of
and C F of the wedges A C H and B C H, Jf we add a [h^t^of ^jj *^
t\'edge B C I opposite and similar to A C H, we shall have fluid exactly as
a straight line H I, and the action C K of this' wedge re-
ducing C E to C L, that of the wedge B C H must be re-
duced in the same proportion, in order that the result may
remain in the direction C D, and the density of B C H
must be made equal to the difference of the densities of
B C I and A C II ; or, if H I be the termination of a sin-
gle solid, that solid must be of half the density of the fluid.
It was perhaps in order to avoid this inference from his first
theory, that Mr. Laplace adopted afterwards a different .^

mode of reasoning.

I shall now examine the consequences of the supposition Consequences
of a repulsive force extending its action to all particles fo;^feJ^^^" '''^^
within a certain very small distance of each other. Since it
is certain, that the particles of all bodies in the state of gas P<:;rticles of gas

repel each other, without any thinaj like the actual contact [^i^*^!.^^ ^®'^^^'
" ' "^ y Die distances,

of impenetrable atoms ; and since it may be shown by ex- as do many so-
periment, that many solid bodies exert repulsive powers on ^^''^^
each other at sensible distances; it is natural to imagine,
that the repulsive force, acting on any given particle, is de-
rived from the joint effect of a considerable number of other therefore re-
particles at different distances from it, in the same manner pulsion the ^
as the force of cohesion is conceived to be derived from the many particles,
joint actions of a great number of particles cooperating with
eacli other; although the repulsive force may naturally be ^nd probably-
supposed, to consist principally in the stronger action of a from the
smaller number of particles. Now if the circle A (Fig. 3) ^f fewer parti-
represent the limits of the force of cohesion, and B those of dt's than ope-
the force of repulsion acting on the ceiitral particle C, it is l^^^ ^^ ^^ ^'

evident, that, if the substance be divided into any number ^,. ,. ,.

J This applied to

of wedges meeting in the point C, the two f^^rces exerted sectors of cir-
by any one of these D C E, upon any other F C G, must ^^^^•
be equal, since the segments are in the same proportions as
the whole circles ; and the effects of the whole circles are

B 2 equal :

4 ON CAPILLARY ACTION.

equal: for, if an imaginary separation. be made in tlie sub-
stance in any direction A C, it is evident, that the cohesive
force, tending to bring all the particles of the two segments
togetlicr, nniist be ex\uix\ to the repulsive force, which prevent;s
their nearer approach ; and, into whatever portions the co-
hciiive forces of the wedges be supposed to be divided, it is
obvious, that for each of these, as for example, the mutual
actions of the particles situate at II and I, an equivalent
may be found in the repulsive force K L, exerted between
the particles whicli are similarly situate within the sphere
of repulsion: consequently, the whole result must be not
only equal, but also parallel: so that, if the wedge F C G
be considered as the termination of a vertical column, the
eflect of the wedge D C E, or of D C G, will have no ten-
Thfi counter- dency either to elevate or to depress that column. The only

tctiou not ab- ^^^^ ^^ pt^pfcct counteraction will be, that the parts nearest
•olutely per- ' _ *^ .

tect. the wedge will be urged more downwards by the repulsive

force, and the remoter parts more upwards by the cohesive

force. In order to understand the effect of a combination

Effect of a of such actions where the surface is curved, let us suppose

combination of ^^^^ superficial particles to be situate at the angles of a po-
such actions. it n i

lygon, A B C D E F G H, (Fig. 4) and the repulsive force

to extend only to the two nearest particles, one on each
side, while the'coliesive force is so distributed, as to have its
general result directed to the next particle but one: it will
then be necessary, in order that there may be an equilibrium
between the ix)!ccs tending to separate and to unite any two
particles D and E in the direction of the surface, that the
cohesive forces in the directions D F, EC, be represented
by D I and I K, while D E represents the repulsive force:
then the forces acting on D being represented by CD,
£ D, L D, and I D, it is evident, that the parts of these
forces which tend to urge the particle D to and from the
line C E, are precisely equal, so that this particle will re-
main perfectly in equilibrium, without occasioning any

Dr Yonng\s pressure on the stratum within it. It is supposed in Dr.

supposition. Young's reasoning on this subject, that the repulsive and
cohesive forces acting on each particle are either accurately
or very nearly equal ; but this supposition, although it ap-
pears

pears at first sight unexceptionable, is in fact inconsistent
with the general principles of the theory.

It appears therefore on one hand, that the considenilion Repulsive force
of a repulsive force is indispensably necessary to the perfect ^'^^^^^y^oThe
solution of the problem ; and on the other, tluit such a force solution; but
as there is reason to infer from experiment is not capable of ^^JJ.^^j^'^J^^^
producing effects similar to those of the capillary affections experiment
of liquids. There appears to be only one way of avoiding "^"^jf^'^X'^j^
these difficulties, which is, to suppose that a part of (he

force of repulsion only is concerned in that actioii which is PaVt of this
J ^ I •' . iorce only sup-

observed at sensible distances, whde another part is so con- ^^^.^^ ^^-.^g. ut
fined to the particles in immediate contact with each other, smsible dis-
th;it if we suppose a liquid to be divided by any imaginary ''"^'^^'
plane surface, the particles on one side of this surface can
only act on the particles on the other side in a direction per-
pendicular to it, leaving them completely at liberty to move
without resistance in the direction of the surface itself. This
hypothesis has been tacitly assumed by Mr. Laplace, with
respect to the whole force of repulsion ; but in any shape it
is still an hypothesis only, and the reasoning founded on it
can only be considered as demonstrative, so far as its results
are justitied by a coincidence with facts and experiments.

Suppose a column or stratum A B (Fig. 5) terminating Supposition of
in a curved surface C D, to be contained between two pa- ^,[^^.jj™ j* a
rallel planes perpendicular to the tangent E F ; then the roncatc sur-
action of the pai tides below E F^ will have no power to ^^^'
move the column in a vertical direction ; but the portion of
the substance included between the curve and its tangent
will tend to elevate it, and the more in proportion as the
curvature is greater; the number of particles within a very
minute distance from the column being directly as the cur-
vature, or, where the surface has a double curvature, as the Surface of dou-
sum of the two curvatures in directions perpendicular to ^^^*^"*"''^^"'^*
each other. And if the line G 11 be every where as much
below E F as C D is above it, the action of the particles,
cut off by this line on the column A B, will be equal to that
of the particles above E F, and will produce an equal force
tending to raise it ; hence, if all these particles be removed,
the remaining parts of the substance below G H will attract
the column with the same force as was before counteracted

by

6 ON CAPILLARY ACTION.

Picssure pro- "by that of the parts removed ; and the pressure will there-
curvature. ^^^^ ^^ every case be proportional to the curvature.
A drop of fluid Heiice if we imagine a drop of a fluid to be perfectly in-
being pert ecty sulated, it is evident, that the superficial parts on one side
' of the drop must press the included fluid towards the other
side, and must consequently be pressed back in an equal
degree, so that at the circumference of the circle supposed,
to divide the drop, the surface must be stretched by the
the tension of whole of this force, reduced only to a single direction ; and

us surface wil ^]^f.y^ must therefore be a uniform tension of the surface,
be uniform m, , , . , i i «• ,

1 he only case which can be supposed to anord an exception

Exception to this demonstration, is that of the surface of a liquid ter-
where the sur- minated on each side bv a solid of precisely half the den-
faceofthefluid . , , -^ • r- v^.i i . , ,

is bounded on ^ity : but it is ot little consequenceiwhat may be the result

each side by a of such a combination, since it is scarcely possible, that it
the density.^ should ever be observed in nature. If it were not true, that
Tension of ^^^^ surfaces of liquids are stretched by a uniform force, it
fluid surfaces wou Id follow, that a coik, wetted on one side and greased
Hjus e eq ^^ ^^^ other, would continue for ever to move, on the sur-
face of a large reservoir, towards the wetted side.
Hence the an- The angle of contact of a solid and a fluid, of given den-
gle of contact sity, may be deduced from the law of equable tension, when

of a solid and a /ir i i • i.- r i ^

fluid may be ^'^*^^ established, in a very satislactory manner. Conceive

deduced. a body, of the density of the solid only, to extend through

the substance of the solid and fluid ABC (Fig. 6) ; the
attraction' of its surface will then urge the angular particle
in the direction B D, with a force which is to the whole ten-
sion as B D to half A B ; then a substance equal in density
to the difference of the solid and the fluid, being superadded
to the wedge C B E, will draw the particle in the direction
B F with a force B F : now in order that the forces in the
directions B D and B F may produce a result B G, capable
of being completely counteracted by the perpendicular at-
traction of the surface A E, they must be proportional to
BD and D G, and the density of the additional portion
C B E must be to that of the solid as D G to B F, or to
D C or A D, and the whole density of the liquid C B E to
that of the solid as A G to A D, that is, by similar trian-
gles, as A E to A H, which is the versed sine of the angle
A ]5 C, A E being the diameter.

Mr.

ON CAPILLARY ACTION. /

Mr. I^aplace's second method of considering tlie effects Laplace's se-

„ .„ , ... J cond method

of capillary action, though not wholly new, is ingenious and iaceiuoi.s, but

satisfactory: but it requires the assistance of the same hypo- requues the

. '' , ^ . K,._ sanje hypothe-

thesis respecting repulsion, as is necessary to Ijis first theory, sis of repulsion

The attraction of a capillary tube A B (Fig. 7) on the co-
lumn C consists of two equal parts, one of which is de-
rived from the action of the part,,D E F G on the upper
portion of the fluid at C, the other from that of the end of
the tube at H 1 upon the portion below at K ; and these
two forces are opposed by the attraction of L M, the part of
the jffuid forming a continuation of the solid, which draws
the column downwards in the same manner as each of the *

other forces draws it upwards : so that the weight of the fluid -
elevated must be proportional to the excess of twice the den- -
sity of the solid above that of the fluid. Supposing the
fluid to be elevated in a verj'^ narrow space of a given
breadth, the half of this breadth being the radius, the se-
cant of the angle of contact will become equal to the radius
of curvature of the surface, which is always inversely as the
height of the elevated column ; hence the cosine of the an-
gle of Contact will be directly as the height, that is, as the
difference between the density of the fluid and twice that of
t|ie solid, the whole density of the fluid being represented
by the radius ; and this determination agrees precisely with
the former.

Mr. Laplace has very justly observed, that where two Laplace's ob-

floatiniJ: bodies are surrounded by an elevation and a depres- servation on

1-1 1 • 1 • 1 I • 1 ■ -HI unequal eleva-

sion which are unequal in height, their repulsion will become tions and de-

a maximum at a certain distance, and upon a still nearer pressions of a
approach will be changed into an attraction. When the floatuig bodies
distance is very small, the height of the fluid elevated be-J"st.
tween the bodies is the mean of the heights to which it
would be raised between two similar portions of the respect-
ive substances, and hence the magnitude of the force may

be readily determined. Dr. Youncr seems to have consider- J^^^^"°^ consi-

^ p dered by Dr.

ed only the case of an equal depression and elevation. Young.

As an illustration of the combined effects of the forces of Combineii ef-

cohesion and repulsion in the constitution of natural bodies, ^^'^^'^ of cohe-
T1111-- 1^. . oi . sion and repul-

1 shall subjoin a short investigation of the magnitude of the sion in the con.

attractive power which retains the particles in solids and stuutionofna-

fluids

S: aN CAPILLARY ACTION.

tural bodies, fluids in their situation, upon the simple, although perhaps
inadequate supposition of a congeries of irjcompressible par-*
tides in contact with each other, actuated by a cohesive
force, which extends, without diminution of its intensity, to
a certain small distance from each particle.

In the series of single particles A B (Fig. 8) the particle
A, being attracted by all the particles between A and C,
the limit of the cohesive force, presses on the next particle
D with the whole of this force, which may be represented
by the line A E : but the pressure occasioned by the cohe-
sion of the particle D is only proportional to the line D F,
which is to A E as D C to A C, because the mutual ac-
tion of D and A takes from the whole cohesive force a part
■which is equivalent to the action of the particle next beyond
C: hence D presses on G with a force represented by the
sum of A E and D F ; and in the same manner it may be
shown, that the whole mutual pressure of the particles at or
beyond C is expressed by the area of the triangle A E C ;
and in general, that it may every where be represented by
the ordinates of the parabolic curve A H, or of the mixtili-
near figure A II I. The same may be inferred from consi-
dering the whole force resisting the division of the series
between any two of its particles.

Magnitude of Suppose now that a single particle A (Fig. Q) is placed
beyond the limit B C of an attractive body ; it is required
to determine the magnitude of the whole force with which
it is attracted. The force of the particles situate upon the
arc B D, when reduced to the direction A D, is represented
by the line D E, since the number of particles in any small
portion B F is as much greater than in E G, as A H is less
than A B; and in the same manner the force of the particles
in the line or narrow ring I K is represented by the line I L;
hence the attraction of the whole segment B D H will be
represented by the area D H E, I L being always equal to
H K, and the curve H E being a hyperbola, which, when
A comes into contact with H, becomes a right line. But
when B C is considered as representing the surface of a so-
lid, the measure of the attraction is the hyperbolic conoici,
QT the coue described by the revolution of the line H E on
H D as an axis ; and hence the attraction of the solid on a

parti c<*

the force of at
traction.

SOLUBILITY OF EARTHS BY WEANS OP SUGAR. A

particle at H is precisely half as great, as if all the parti«
cles within the hcmisphe|^e of cohesion were situate in the
line H D. If we take H M = A D, and make the ordi-
nate A N every where proportional to the content of the
conoid corresponding to the distance A H, the curve M N
will approach at M infinitely near to a parabola, and at O
will become parallel to A H ; and the area A M N will ex-
press the sum of the attractions of a series of particles ex-
tending froui M to A, and consequently the proportional
attractive force of two solids situate at the distance A ti-
lt is easy to show, by a fluxional calculation, that the area
H M (3 is half of the rectangle MHO, and consequently*
that the mutual action of the substances when in contact, is
half as great, as if all the particles of the one body withia
reach of the cohesive force of the other, were situate imme-
diately at its surface.

If one of the bodies be equal in thickness to the distance
to which the cohesion extends, it will still be attracted by
the whole force of the other: but if its thickness be lesp,
and equal, for example, to A H only, the attraction will be
expressed by the area A H O N only, which is ultimately to
the whole area H M O as twice A H to M H. This is per- j^x's a © nts
haps the reason, why the superficial particles of liquids are f^r the process
easily detached by the action of heat, in the process of slow "jfj^^"^ ^^^^*
evaporation.

I am. Sir,

Your very obedient servant,
20 Julf/, IS07. ' ALETES.

II.

On the Soldbilky of some of the Earths hy means of SugOr,
By Mr, William Ramsay.

SIR, Clasgowy July 14, IQ07^

i^HOULD you think the following experimeTits, on the
solubility of some of the earths by means of sugar, worthy

of

10 SOLUBILITY OF EARTHS BY MEANS OF SUGAR.

of notice, you are at liberty to publish them in your valua-
ble Journal.

I am, Sir,

Your most humble servant,

AVILLIAM RAMSAY.
Wm. Nicholson, Esq.

London.

Quicklime BEING employed in making experiments on sugar, and

tostetosohftion ^^PP^ning to put some quicklime into a cold solution of
of sugar. it, I noticed, that it had acquired an uncommon caustic

taste.
Sugar dissolved Uncertain whether sugar dissolved in common lime water
different ^^^"^ '^ might not have the same taste, I prepared a small quantity,
and added sugar to it; but the taste of the solution was
very little different from that of sugar dissolved in water.
On adding diluted sulphuric atid to the former, a copious
precipitation of sulphate of lime took place, while the latter
scarcely showed any traces of the presence of lime by the

Sugar dissolves Hence I concluded, that sugar possesses the property of
*""5* dissolving a certain proportion of lime ; and in order to as-

certain its capacity in this respect, the following experi-
ments were made upon this earth, together with barites,
strontites, magnesia, &c.
Solution of su- One pound avoirdupois of common unrefined sugar was
^'^^* dissolved in rain water, and the solution tiltered ; the speci-

al 50°, fie gravity at the temperature of 50 degrees of Fahrenheit's

thermometer was found to be 1040. This solution was used
in all the following experiments as a standard, to which the
earths were added at tirst at the temperature of 50 degrees,
dissolves lime A portion of the saccharine solution was taken, quicklime
was added to it in superabundance, repeatedly liltered, and
fresh portions of the earth given to it,- until the solution
was evidently saturated ; when the specific gravity was found
to be

Solution of sugar 1020

Increased sp. grav. from lime in solution • 40

1060
Consequently

in

SOLITDILITY OF EARTHS BY MEANS OF SUGfAR. | I

Consequently sup^ar dissolved in water at the temperature of t^^e proportion
50 degrees is capable of dissolving one half pf its veeight of sugar.^'
lime.

As most salts combine with greater facility, and in gene- Heat does not
ral in lafger proportion by the medium of heat, it was J^s^solvenT^^*
thought, that the action of the sugar on the lime might be power,
increased, and a greater quantity of it dissolved, at a higher
temperature. Fresh quicklime was boiled in the solution of
sugar. On filtering and cooling the liquid, it was found,
that very little of the earth was dissolved. On the addition
of dilute sulphuric acid, a slight cloudiness only appeared ;
but by the addition of oxalic acid to another portion of the
liquid, a precipitation of oxalate of lime took place, which
was estimated at about t\^ce the quantity of lime that would
have been precipitated from common limewater by the same •

agent.

The solution of lime in sugar is of a beautiful white wine Chemical pro-
colour, and has the smell of fresh slacked quicklime.

It is precipitated from the solution, by the carbonic, citric,
tartarous, sulphuric, and oxalic acids. And it is decomposed
by double affinity, by caustic and carbonated potash and
soda, the citrate, tartrite, and oxalate of potash, &c.

Having ascertained the quantity of lime that is dissolved Sugar in solu-

in a o-iven quantitv of susirar, I next tried it as a solvent of t>on dissolves

", ^ - , l-4tn or stron-

strontites. Two ounces of this earth were taken, and the tltes at 50",

carbonic acid expelled by dilute nitric acid; the mixture vt'

was evaporated to dryness, and then put into a crucible in

a red heat, until the nitric acid was decomposed. A portion -

of the solution of sugar was taken, and the earth added to

it in the cold state ; the specific gravity was increased to

1050. This solution was boiled on a fresh portion of earth, and an equal

and the liquid immediately filtered; for some time it re- weight at 2 12%

malued of a pure white wine colour, but as the liquid cooled, ^ains at 50''.

it gradually deposited a number of gray coloured crystals,

which are soluble in water, and have the same taste as the

saccharine solution of strontites. At the temperature of 50

degrees, the specific gravity of this solution was as under.

Solution of sugar • • 1 040

Jncreased sp, grav. from strontites in solution • • • • 40

1080
Consequentlj

Consequently an equal weight of strontites with the sugai-
employed is capable of being- dissolved at the temperature
of 212 degrees; and of being retained in solution by the
sugar at 50 de^rpes of Fahrenheit. On exposiui^ the crys-
tals, which had fallen down during the cooling of the liquid
to t})e air of the atmosphere, tjiey attracted carbonic acid
and effloresced. . ' •

Chemical pro- The solution of strontites in ay^ar Is of a fine white wine
**^'^^' colour, and like that of lime has a peculiar caustic smell.

This earth is precipitated by caustic and carbonated jfotash
and soda; also by the carbonic, citric, tartarous, sulphuric,
and oxalic acjds. And it is decomposed, by compound af-
^nity, by the carbonates of potash and soda-; also by the
citrate, tartrite, and oxalate of potash.
Sugar and ba- Judging from the greater solifbiiity of strontites when
fyies. compared with lime in the saccharine solution, that this

flight pvoceed from its superior affinity for this substance ;
it was thought, that a greater proportion of barytes would
"be dissolved than of either of the former earths. Two
ounces of the carbonate of barytes were taken, and treated
in the same manner as has been narrated in the preparation
of the strontian earth, by ex;pelling the carbonic acid by
dilute nitric acid, evaporating to dryness, and then igniting
the mixture until the nitric acid was destroyed. The pre-
pared earth was put into the saccharine solution in the cold
state, and frequently agitated ; the liquid assumed a dull
greenish appearance, and the smell of carbonated hidrogen
gas was sensibly felt. After 24 hours rest the solution had los$
its green colour, and was of the same colour as the original
Nonedissolved solution of sugar; and a black matter was found precipitated
fold, to the bottom of the glass jar. . On trying the specific gra-

vity of the solution it was not increased. The liquid was
then taken apd boiled on a fre^ih portion of the barytic earth,
and bat little *'"^" fil^i'^d ; on being cooled to the temperature of 50 de-
hot, gi'ees, the specific gravity was

Solution of silgar 1040

Barytes in solution 6

104<i
From

SOLUBILITY or EARTHS BY MEA^S Of SUGAtl. 13

From the result of this experiment beinp^ so very difFer(?nt Theexperi-
, i. • ,• 1 • T 1 "lent repeated,

from those preceam$]^ it on \ni\e and strontites, 1 supposed,

that some change had taken placie either in the sugar or ba-
rytes ; the experiment was therefore repeated several times,
but always with the same result. The barytic eartli, which The barytes
was left on the filtering p»per, was put into dilute nitric acid, k^/" '^,j^j*^*
and a violent disengagement of carbonic acid gas took place,
iiltho'igh the whole of this gas was apparently expelled be-r-
fore the eartli was introduced into the saccharine solution.
The same portion of earth was treated in the same manner Repeated with
thrice, and on expelling the carbonic acid and introducing
it into the saccharine liquor, the specitic gravity was not ^.

farther increased; the liquid always assumed the greenish
appearance before noticed, and when in this state carbonated
hidrogen gas was evidently disengaged, and a bldck floccu-
lent matter always subsided before the liquid became trans-
parent.

From these appearances one would be almost ready to Probably the
conclude, " That barytes, by its superior affinity with the pog^^jj^J^^jj-^^gJ
*' carbon of the sugar, is capable of decomposing it ; that by its affinity
" part of the carbon, in union with the baiytes, is precipi-
'1**tated along with the earth in its carbonated state; and
*^ that the oxigen of the sugar, being set at liberty, unites
" with the hidrogen and another portion of the carbon, and
*' is disengaged in the state of carbonated hidi-bgen gas.**
But as I cannot say, that the earth and the nitric acid were
in a state of absolute purity, on this account I dare not trust
entirely to this explanation, and only state what took place
during the course of making these experiments. ^

I next tried the power of the solution of sugar on mag- Magnesia very
nesia. One half ounce of this earth calcined was added tO J'ttle soluble ia
the saccharine solution in the cold state, without the specific
gravity being perceptibly increased ; the mixture was then
boiled, when on filtering and cooling the liquid to 50 degrees,
the specific gravity was -

Solution of sugar 1040.000

Magnesia in solution • • 3.050

1043.050

The

14 SOLUBILITY dF EART*HS BTf kEANS OF SUGAR.

Chemical pro- The salutioii of magnesia, like those of lime and slron-

pcrtie*. tites, was of a j)ure white wine colour, and had no sensible

variation in smell or taste from the common solution of su-*>

gar ; farther than that the sweet seemed much improved,

and was softer and more agreeable on the palate, as if it

were entirely freed from the earthy taste, which unrefined

sugar frequently has. On its remaining at rest for some

months in a bottle well corked, the magnesia appears to be

entirely separated.

Alumine but Very little alumine is dissolved by a solution of sugar,

little soluble when fresh precipitated earth is presented to it either in thfe
in sugar. , .

cold or hot state. Neither does it seem capable of holding

it in solution, when sulphate of alumine is decomposed by

sacchariie of lime in the way of double decomposition : both

the lime and alumine are precipitated together. But when

fresh precipitated earth of alum is boiled for some time in

the saccharine solution, it seems capable of attracting the

colouring matter of tlie sugar, and the liquid, when the earth

Perhaps it has precipitated, is in a purer state than before. Perhaps

might be use- ^.-j-j^ certain modifications this au-eut might be of service in
Jul la refining . o o

it. the refining of sugar.

Alkaline car- The union of sugar with the alkalis has been long known ;
ra^teThe earTli ^"^ *^^^® ^^ rendered more strikingly evident, hf carbonated
from sugar. potash or soda (for instance) decomposing the solutions of

lime and strontites in sugar by double affinity.
Weak sugai^ In making solutions of unrefined sugar for culinary pur-
contain lime, p^ggg^ .^ gj-^y coloured substance is found frequently preci-
pitated. It is probable, that this proceeds from a super-
abundance of lime, which has been used in clarifying the
juice of the sugar cane at the plantations abroad. Sugar
with this imperfection is known among the refiners of this
article by the name of weak. And it is justly termed so,
the precipitated matter being nothing but lime which has
attracted cal-bonic acid from the sugar, (of which there is a
Lime separates great probability) or from the air of the atmosphere. A
from sugar ia bottle in which I had kept a solution of lime in sugar for at
state of a car- ^^^^t four years closely corked, was entirely encrusted with
bonate. a yellowish coloured matter, which on examination was

found tp be entirely carbonate of lime.

III.

NUTRITION OF VEGETABLES*

III.

is

Inquiries concerning the assimilating Pouter in Vegetahles; hy
Mr. Henry Braconnot: read at the Academical Society
of Sciences of Nanci, November the 22d, 1 806*.

_ HYTOLOGISTS for a loni? time imagined, that vege- Supposition

, , / . , , , ... 1 • 1 ^1 ' ^ ^ J that vegetables

tables were nourished by certam juices, which they extracted extracted nu-

ready formed from the earth. Van Helmont in great mea- triiious juices
sure refuted this by his celebrated experiment. In a box refu*ed by Van
containing 100 lbs. of earth, and covered with lead, he Helmont,
planted u willow, weighing 50 lbs. TJiis he watered with ^^^l^^^ ^^^
distilled water, and in five years it had acquired an addition
to its weight of 1 19 lbs. 3 oz. without any perceptible dimi-
nution of the earth. The experiments of Boyle with earth
baked in an oven, and those of Duhamel and Bonnet with
mossf, prove the same thing.

Other natural philosophers have pursued the same in- Tiliet showed
quiry: Tiliet, in particular, made a number of experiments, ^nTto^eTe-
to ascertain whether water and air were the only substances cessary to their
necessary for the growth of plants. He filled several pots S^o^^^ •
with different earthy matters, some with old plaster, others
with pure river sand, fragments of stone broken to powder,
&c. ; buried them partly in the ground, to retain the moist-
ure; and sowed wheat in them. The wheat produced very
fine ears ; and the grains, being sown, produced other fine
plants.

From the infant state of chemistry, at the time, however, None of these
none of the plants produced by means of air and water alone ^^ ^" ^ ^"* ^^*^
were analysed. This indeed has since been done ; and it has
been advanced, that plants growing in such a manner as to '^^^^ plants ^'
have been nourished by water alone, did not furnish as much contained less

* Abridged from the Annales de Chemie, Vol. LXI. p. 187. Feb. 1807.

■\- Mr. Procoplus Dcnsidoff of Moscow, who has a very fine botanic Seeds mpstdif-

garden, raises all sorts of plants bv a peculiar method. He sows the ^*^^"' ^" S^*^"/^"

J. ,, ■ ^ , ^ • , ,. w nate succeed

fseeds m moss, where they germinate, and then plants them m pots. In -^ moss

this way he loses very few seeds of those that grow with most diffi-
culty. Note o/ Prof. Willmett^

carbon

16

kutrttion of TrAtXAttV,^,

Its products.

carbon than cart>on as was contained in the seeds from which they sptUn^ ;
while those in mould were much more vigorous, in conse-
quence of the carbon with which it furnished their roots.
But these experiments were on too small a scale to furnish
satisfactory results; and I have therefore attempted to inves-
tigate the subject anew, in order to ascertain, how far this
opinion is well founded.
Mould first As a preliminary step, T conceived it necessary to analyse

analysed. vegetable mould in a state of perfect decompoiition. F or

this purpose I selected perfectly pure, black, pulverulent
mould, from among the hollow roots of a very old ti'ec.
Contained no- Distilled water, in which it was boiled, remained colourless
thing soluble after filtration, and on being evaporated left no sign of any
in water. i v i ^.

soluble matter.

Very retentive A hundred grammes [3| oz.] were reduced by dessication
of moisture, ^q oy^ which shows it to be extremely retentive of water.

These "20 gr,, distilled at a red heat, gave out 4 of water,
that powerfully reddened infusion of litmus; and contained
empyreumatic acetous acid, partly saturated with ammonia;
2 of an acrid oil, that congealed on cooling, and was of a
dark brown colour; 89 cubic inches of oily hidrogen gas,
burning with a blue flame; and 34 cubic inches of carbonic
acid absorbed by lime.

The coally residuum weighed 8*5 grammes, which were
reduced by incineration to 2*4 gr. of light yellow ashes.

Boiling distilled water digested on these ashes acquired nO
peculiar taste, did not turn sirup of violets green, and was
barely rendered turbid by the addition of a few drops of
oxalic acid, which seemed to indicate, that a few particles
«if lime had been set free by the calcination. The nitrates
of barj^es and of silver produced no change in it. On far-
ther analysis these ashes afforded 1*3 of a gr. of silex, "3, of
oxide of iron containing a little oxide of manganese, '25 of
phosphate of lime, '2 of lime, and some traces of magneVia.

I belled G gr. [92 grains] of the same mould for an hour,
i^^ol r>«^"^^ a strong solution of caustic potash, when it became glu-
tinous, and swelled up. I then diluted it with water fil-
tered, and obtained a very deep brown liquor. This mixed
if lib the lixiviating waters gave on the addition of an acid
a precipitate, that weighed 1 gr. when dried. It was of a

ver/

Residuum.

Ashes.

The mould
boiled in sokl
tipn

NUTKITION OF VEGETABLES. ly

very Hack colour, ^md in little shinin*^ scales. Scarcely
any vapour arose from it when throvvi) on burning coals, and
1 consider it as charcoal well saturated with hidroj^en. Art
nmy imitate this substance, by effecting by fire what nature
does by time. If we deprive a vegetable substance of al-
most all its oxigen, and a small quantity of its hidrogen, by
exposing it to a certain temperature, the result will be a hi-
droguretted charcoal, partly soluble in potash, as I have
found by experience.

That part of the mould, which had resisted the action of The residuum
potash, weighed when dried 5 gr. It had no longer the phy- ^0^1?'^^°*^ ^'*^'
sical characters of mould ; was in pieces that were tolerably ''l^ii

hard and brittle; and had a striking resemblance to pitcoal,
which led me to produce it in larger quantity. In this way
it had still such a resemblance to coal, that I could com-
pare it to nothing else.

From this examination of mould it appears, that it can- It afFords no
not supply plants with any soluble matter for their nutrition, ^^^"^^^ matter
since boiling water has no action on it. It would be super-
fluous to say, that seeds sowed in it vegetated with extraor-
dinary vigour; but I must not omit to mention the presence
of a large quantity of potash in the plants, though I could
not detect any in the mould in which they grew, by the most
strict researches.

These observations appear to corroborate the opinion of Manure thcre-
Tillet and Parmentler, who consider manure as useful only ^""^^^ seems to
by retaining moisture, and keeping strong soils open for by retailing
some time, so as to allow the roots of plants to penetrate "Jointure.
them. But if water and air be the only sources of the food
of plants, any insoluble matter, sufficient in quantity, and
duly watered, must be adequate to the purpose of their
growth. This I endeavoured to ascertain by experiments.

Exp. I. In a box tilled with pure litharge I sowed 400 Mustard seed
seeds of white mustard, weighing 2*2 gr. These I watered -o^^" '" ^i-
frequently and carefully with distilled Avater. The box was ^^^^^^'
placed in a good aspect, and a glass was hung over it to
keep out the dust. The plants throve very well, and pro-
duced perfect pods. I collected all the seminal leaves as
well as the rest that dropped off; and when the vegetation
was at its height, pulled up the plants. Having well washed

Vol. X VIII— Sept. I807. C the

18

NUTRITION OF VEGETABLES.

the roots, to remove any portions of oxide of lead, and wiped
them dry* the whole weighed 264 gr. After thej were dried,
the weight was 34*2 gr.
The produce These yielded 12 gr. of coal, which by incineration were
analysed. reduced to 4'2 gr. of ashes. These lost by lixiviation 2*2

gr. ; of which '59 gr. were sulphate of potash, '6g gr. pot-
ash. The insoluble residuum aftbrded '4 gr. of silex; '45
gr. of oxide of iron, alumine, and phosphate of lime, the
proportions of which were not determined ; '57 gr. of ox-
ide of iron ; and a very small portion of magnesia.
Mustard seed Exp. II. In a very large, deep, and perforated bowl of
of sulphur. stone ware, filled with well washed flowers of sulphur, 250
seeds of white mustard were sown. The whole was covered
with a large bell glass, allowing free access to the air and
light. The plants grew vigorously, being frequently wa-
tered with distilled water ; as sulphur, having little affinity
with water, parts with it very easily, and dries on the sur-
face. They produced flowers in tolerable abundance, and
The produce the seeds produced plants in common groimd. The weight
analysed. ^^ ^^^ f^,^^^ plants, with the fallen leaves, was 108 gr. ; and

when dried 18*6 gr. Their coal weighed 7*8 gr. and left
1*55 gr. of whitish ashes, which aflbrded by lixiviation '6 gr.
of carbonate and sulphate of potash. The insoluble part was
similar to that of the former.
Mustard seed Exp. III. A hundred seeds of white mustard were sown
sown m small ^^ twenty pounds of very smaU unglazed shot, on the 9th of
July. On the 28th of August they began to flower, and
aflbrded small pods. All these plants were slender, and had
but few and small leaves. When fresh they weighed 10 gr.
and after being dried 2*3 gr. they yielded very little coal,
but more than the weight of the seed. The weight of the
shot appeared to oppose too great an ebstacle to the young
roots, as most of them spread over the surface, without
being able to penetrate it. The iittle affinity of the lead for
water was another reason of the feeble growth of the plants ;
and hence I have found, that plants thrive less in metallic
powders, than in their oxides.
Radish seed Exp. IV. On a flat stone pavement a bed was formed,

s.mn in aheap ^^^^^ a yard hit;h, of fine sand, taken immediately from
of sund, . o ' .'

the bed of the river, and well washed. In this were sown

seeds

NUTRITION OF VEGETABLES. jl^

seeds of the common radish fraphanvs sativnsjy which were
fiequtntly watered witli perlectly pure rain water, and the
■plants grew with as mucli vigour as they would have done in
any ground. The greater part of the radishes were brought
to table, and were of a very delicate flavour, without any
of the disagreeable earthy taste they have sometimes. Some
of them were left to seed; and most of these grew to the
height of 2 feet or 2j. It was observed, that those at the
top of the heap were much larger and stronger than those
near the bottom*.

Sixty three of these plants when dried weighed 372 gr. 'Hie produce
Incinerated they left 54'2 ^v, of gray ashes. These afforded ^^^'y^ed,
by lixiviation 18'6 of very fine potash. From this I am in-
clined to think, that the radish might be cultivated with ad-
vantage on wet sandy places by the sea shore, for the pur-
pose of fabricating potash f. Th<ise 18'"6 gr. being farther

analysed,

• A skilful gardener informs me, that asparagus too will succeed very Asparagus and
well ill pure river sand. Potatoes also grow well in sand, and are said to potatoes grow
be better tasted. ^^^ii in saad.

•f- It appears, that potash abounds in all the plants of the class tetra- Potash abounds
dynamia, and the ashes of some of the species were long in use for in tetradyna-
making soap and glass, before the introduction of soda as an article of ^^^^ ^ ^" ***
trade. According to Bomare, the bunias cakile, sea rocket, was much
employed for these purposes.

I must here add an observation, which appears to me pretty general, Acrid and bit-
and which I made in examining the acrid and bitter properties of plants. ^'^^ plants ge-
One or other of these principles 1 have almost always found in con- ^^^^ J^ "
junction with a large quantity of potash, which was frequently saturated quently coni-
with nitric acid. Thus among the cruciferous plants, which are ail more bined with ni-
or less acrid, the sisymbrium nasturtium, common water-cress, afforded ^^^^ ^c\d,.
nie a great deal of alkaline matter after incineration j and when frCbh I
found in it nitrate of potash. I have observed the nitre melt on incine-
rating cabbages and turnips ; and Mr. Delaville found this salt in large
quantity ia the sop of these plants. Mr Bouillon-Lagiange found a
large quantity of potash in the ashes of the crigeron canadense, Canada
fleabane, which is acrid. The ashes of tobacco, the acrimony of which
is well known, yield 40 per cent of potash. Among the bitter plants I
have examined, 1 found niirate of potash in the fumitory, 100 parts of
the a^^hes of which contain more than G6 soluble jn water, according to
Wiegleb and Rukert. The common centaury, marsh and Siberian tre-
foil, and different species of the genus centaurea, which are very bitter,
afford ashes in wVuch potash abounds. Whether in these plants it be

C ^ saturati'd

20 NUTRlTtON OF VEGETABLES.

* . analysed, were found to contain 6*7 of pure potash ; 7-35 of

sulphate of potash; a small quantity of phosphate of lime ;
and the rest was carbonic acid.

Residuum con- Thg residuum left after lixiviatine: the ashes appeared to
tained sulphur. . ,, , ..., ...

contam sulphur, as on pounng nitric acid over it sulphuret-
ted hidrogen was given out ; but I could not find any phos-
phoric acid in it. I did not examine it for the earths, as
these might have been said to have been taken up from the
sand.
Compared with Having thus examined these plants, I thought it might
from •r'irdeii ^^^ ^^ amiss to compare their produce with that of some
irioui'd. others, which had grown in common garden mould. Of

these dried 372 gr. afforded but 34 of ashes, which it is true
were very saline, and yielded l6 gr. of saline matter, con-
sisting of carbonate and sulphate of potash. In the incinera-
tion of these plants too I observed a very copious production
of ammonia, on pouring a little water on their ashes while
gtill hot.
Whence these -^"^ whence come these earths, alkalis, acids, metals, snl-
substancts phur, phosphorus, found in plants, that have had no ali-
nomished only ^""^"^^ ^^'^ P^''^ water? Can vitality, 'in conjunction with
with water? light and heat, determine certain quantities of oxigen and
Are they all hidrogen to form by peculiar condensations those substances

formed ftorn w]^j(.}j j^^ve been considered as simple? this mlaht put us on
oxigen and hi- . . i i i

drogen? examkiing in a new point of view all those substances, that

chemistry has not yet been able to decompose, and thus per-
haps the conjectures, that have been advanced by some, may
be verified,
U\t the same We may even extend these remarks to animallzation, sup-
withaoimals? ported by the well-known experiment of Rondeletius, who

saturated with nitric acid I have not ascertained. I must observe, how-
ever, that 1 have found no nitric acid in wormwood, 100 parts of the ashes
of which afford nearly 75 of saline matter, according to Wiegleb. This
The alkali large quantity of alkali has appeared to me to be partly saturated with a
partly saturat- peculiar inaiter, which is deposited by a decoction of the fresh plant,
cd with a pe- and may be precipitated abundantly by nitrate of lead. This matter dis-
cuhar matter: solves very well in alkalies neutralizi)ig part of their properties : it is the
same that Mr. Vauquelin has found in some species of cinchona. Does
is-itcin hon'n ' ^xist in all b.tier plants? and is it this which in chichona and worm-
wood cures iritermittent and low fevers ?

kept

NUTRITION OF VEGETABLES. 21

kept a fish in pure v;ater, till it grew too large for the vessel x©

containing it, and by other similar experiments on different "' *^

animals. It would even seem, that food acts on the stomach p^^g ^^^^j ^^^

in a great measure as mould does on the roots of plants, on the stomach

merely retaining water in such a state of division, as to fit it JJ^^Jfij jj^ ^^^

for absorption and assimilation. roots of plants?

From what has been said it appears, that foreign matters Matter-; dis-

dissolved in water only check the progress of vegetation ; but ^n^J^^^jol" To^'^'^

that the vital powers can sometimes surmount these obstacles, vegetation.

appropriating only the pure water, that held these matters in

solution.

If experiments founded on lono: practice were still neces- Absence of so-
1 1 -1 • 1 1 /> luble matter

sary to prove, that the soil is so much the more proper tor advantageous,

vegetation in proportion as it is deprived of soluble foreign as appears
matter, I would mention the practice of paring and burning ^f p^rin^ and
wastes, used cliiefly in England. Lands thus treated remain burning j
in heart a long time ; the parts where the heaps of surface
mould were burned are most fertile ; and manure even ap-
pears to be injurious, by causing the wheat to run chiefly to
straw, with thin ears, and those of bad quality.

This extraordinary effect of torrefaction on the soil ap- ^^^I'ch proba-
pears to me attributable to the combustion of those excre- strovint the ^
mentitious matters, which are ejected by the roots of plants, matter excret-
When the soil is impregnated with these matters, which are roots of plums.
eminently injurious to vegetation, the perfect developement
of plants is prevented. This excretion from the roofs is evi- This excretion
dent from the surrounding earth, which becomes unctuous, f"ct^. '°^^
and sometimes of a darker colour. In several of the euphor-
biuras and cicoraceous plants it is very perceptible, and
milky. It may be observed too, that roots, when they multi-
ply under water, become covered with a glairy matter, which
deserves to be examined ; and which no doubt the earth
would have absorbed, had the roots remained buried in it.

It is to these excretions from the roots perhaps we must fre- ^"^ prob biy

^, .,,-,,„ • 1 1 . the cause whv

quently ascribe that kind of antipathy between certain some plants '

plants, which are never found together. Thus the thistle is particularly in-
injurious to oats, euphorbium and scabious to flax, elecam- {j^^ers
pane to carrots, fleabane and dnrnel to wheat, &:c.

It would cei^ainly be wrong, to ascribe the fertility of land Effects of par-
pared and burned to the charcoal produced in this operation ; Jr^g and burn-

r ing cannot be

22 NUTRITION OF VEGETABLES.

«wing to char- f^^ Mr. Cliaptal ]ias shown, that dry charcoal, alone or mixed
>cith earths of little solubility, does not penetrate into the
vessels of vegetables.
P'lantsaonot To add to the proofs, that vegetables have no need of
from the Sxith. ^^'^^^'"g carbon from the earth, I might mention high trees,
loaded with fruit, tliat grow and thrive on rocks or old walls,
totally destitute of vegetable mould ; and those vast forests,
the soil of which is pure sand extending far beyond the
roots.

Opinion that J have now to examine the opinion, tliat vegetables absorb

they derive it , i /. n • ,» i •

from the at- their carbon from the small quantity of carbonic acid con-

niosphere. tained in the astmosphere. Sennebier first announced this

decomposition ; and T. Saussure afterward endeavoured to

prove, that this very small quantity would be sufficient for

all the vegetables that exist. But though this philosopher

was persuvded of the utility of carbonic acid in vegetation,

. be satisfied himself, that plants could grow in an atmospliere

freed from it ; and he ascribed this grovvtii to the carbonic

acid produced by the plants themselves, which they decom-

^erimem^ *^^ posed after having formed it*. To prove this he exposed to

the sun closed receivers, in which plants were growing, and

suspended quicklime to the upper part of them. The plants

soon grew yellow, and at the expiration of five days gave no

signs of vegetation ; whence he inferred, that the absorption

of carb<mic acid by the lime was the cause of their death,

and that the elaboration of this acid was necessary to veget-

The plants kil- ation in the sun. But I cannot be of his opinion. I have

iK>urof the^*" examined the experiment careruUy, and satisfied myself,

lime. that the death of the plants was not owing to the privation of

carbonic acid alone, but to the lime itself in vapour.

The following experiments convinced me of the volatility
of lime.
Jiine is in some ^' i^^^per tinged by repeated immersion in infusion of lit-
. measure yola- uiu$, then reddened, and afterward washed in water to re-
move its excess of acid, was suspended in a stopped phiul.

* It is obvious, that the carbonic acid formed byAhe plants could not
furnish them with more of its base than it luid jjreviously taken from
them. Tr.

1 into

NUTRITIOJI OP VEGETABLES. 23

into which I had put with great caution some lime, that was
slaked, and suitably moistened with water. It was not long
before the red colour of the paper was changed to blue.
This effect was not unknown to Fourcroy.

2. Into a retort I put with all possible precaution a certain ^^^^^^ ^
quantity of lime and water, and by distillation I obtained a
liquor impregnated with an intolerable smell of lime. This
liquor left a disagreeable impression on the palate, and had
manifestly alkaline properties.

Alcohol by its volatility carries up in vapour a much larger Still more rises
quantity of lime, as appears from an experiment of Proust. "^^^^ ^P'"^-
In order to obtain spirit free from acetic acid, he distilled
25lbs. of red wine with a handful of quicklime. The pro-
<luct was so much impregnated with the taste and smell of
the lime, that he was surprised. When redistilled it had
the same taste, precipitated metallic solutions and oxalic
acid, and restored tlie blue of litmus.

Lime is not the only fixed alkali, that shows a disposition Other fixed al-
to rise at a pretty low temperature. kalis^nse at a
A solution of potash, subjected to distillation, afforded me p^^ ^^^ ,j ^j^^
a water with a strong lixivial smell. This water redistilled led.
retained the same smell, and gave with nitrate of lead a
white flocculent precipitate, which was completely soluble in
distilled vinegar.

But there are other substances beside alkalis, the volatility Other snbstan-
of which is so little apparent in the temperature of the at- ^^j partially
mosphere, that it is discoverable only from its effects on
organized beings.

Some Dutch chemists set plants in water, by the side of Quicksilver.
which they placed, a small bottle of mercury, and covered
the whole with a jar standing in water. On the third day
the plants were covered with black spots, and on the fourth,
the fifth, or at latest the sixth, they were entirely black.
The effects were the same when the jar rested on pieces of
cork on a table. Other plants lived a long time under simi-
lar circumstances except the presence of mercury.

Sennebier and Hubert too have shown, that the vapour Other vapours
of sulphuric ether prevents germination from taking place, i"i""o"sto
without altering the quantity of the air. Camphor, oil of
turpentine, assafetida, vinegar, ammonia, bodies in a state

of

34 NUTRITION OF VEGETABLES.

of piitrctaction; &c., have the same effect. Hence we may

infer, that all those matters, which are injurious to animals,

seitsibly affect vegetables likewise.

Carbpuic acid \\q cannot therefore lay much stress on Saussure's expe-
not useful, ...

nments to show the utility of carbonic acid in vegetation,

particularly when we recollect an experiment of Priestley's,
which proved, that an atmosphere with an ei^^hth part of
but injurums carbonic acid was sufficient to kill two plants of mint, though
proportion ^'^^ ^^'^ Small quantity of acid was ia contact with a large sur-
face of water.
Seeds germi- Having found by experiment, that seeds germinate very
ide of lead ^^^^^ '" oxides of lead, which are known to be greedy of car-
bonic acid, I conceived, that these might contribute to elu-
cidate the question respecting the utility of carbonic acid in"
vegetation. In consequence I moistened with distilled wa-
butnotif re- ter some recently prepared oxide of lead in the lirst stage of

ccntiv ofC" •

pared oxidation. This mixture I introduced speedily into a flint

glass bottle : and though the disagreeable and as it were al-
kaline smell that arose from it, led me to doubt the success
of my experiment, t sowed some mustard seed in this oxide,
and included in ajjfl corked the bottle tight. As I foresaw, no germination
took place : but what I was far from expecting, and to my
The lead partly great surprise, part of the oxide of lead in the water was re-
re uce , duced by the seeds, each of which was enveloped by a shining
coat of metallic lead. This appeared to me to be very pro-
bably owing to a production of water by the union of the
oxigen of the oxide with the large quantity of hidrogen, that
is condensed in this oily seed, which after the reduction was
more or less carbonized.
If tlie oxide ^^ ^^^ oxide of lead be left exposed to the air for some
have been ex- time after it is made, and then put into a bottle with water
siiT*the°ceds ^"^^ seeds, no reduction of the metal will be effected, but
grow. germination will take place.
Oxide of lead These experiments show the extreme facility, with which

easily reduced the oxides of lead are reduced, and the obstacle that car-
unl-ss carbonic , . . , ^ ^i • j i-

aci»l prevent it, bomc acid opposes to this reduction.

As these first attempts did not afford me the result I

sought, I availed myself of an old experiment of Huyghens,

Seeds so'wn in who, in l672, put some earth into a bottle, corked it up, and

siliceous earth, f^^j^d i^ produce such a quantity of plants, as almost to till

ties, ' the

NUTRITION OF VEGETABLES. g5

the bottle, without having had any fresh air admitted to it.

Accordingly I procured six large flint glass bottles, most of

which were square: filled them iu part with very fine white

sand, which I deprived of all calcareous earth by washing

with weak muriatic acid; and moistened this with distilled ^jj.j. .,

water. The remainder of the bottle was filled with atmos- presence of

pheric air freed from carbonic acid. carbonic acid.

In these bottles having sowed 460 seeds of white mustard,
I closed them very accurately, and plained them a few inches
deep in a moist soil. Vegetation soon commenced, and con- They grew, ,
siderable vertiure was produced*. After six weeks growth
my plants were liberated from their prisons, washed with
great care, and dried. Tn this state they weighed J) gram.
[140 grs.] I filled a phial with them, which terminated in a
narrow tube, and exposed it gradually to a strong heat.
Thus I obtained 4 gr. 8 dec. [74 grs.] of coal. But as I
supposed this coal might still contain a fittle sand, I incine- carbon
rated it, and found 3 gr. 3 dec. [51 grs.] of very alkaline
ashes. Consequently there was if gr. [23 grs.] of pure
carbon.

In a very small vessel I distilled 460 white mustard seeds,
and from this highly hidrogenatcd seed I obtained only 4 gr,
[6-2 grs.] of coal, which lost near half its weight by calcin- In larger quan-
ation. Hence it follows, that 460 mustard seeds acquired in ^^^^^^ ^^'"^ '^*
close vessels upwards of a gramme [l5j grs.] of pure carbon,

• It may be supposGd, that these seeds did not germinate with as r„.
1. • .... . rr,, . , r , , , The plants

much vigour, as it in the open air. This however 1 do not thtnk must grew weakiy

be ascribed to the want of oxigen ; for by trial of the air with a sulphuret ij^^ ^^^ f q_

before and after the experiment, its proportions appeared to be nearly the want of oxi-

same. This is agreeable to the experiments of Hassenfratz, who con- S^n.

vinced himself, that plants do not diminish the quantity of oxigen in a

confined atmosphere : and I am inclined to think, that oxigen acts on

plants merely as a stimulant, which is not indispensable, for Homber* "■

found diiferent seeds germinate in the vacuum of an airpump. The

principal cause, that prevents the complete dcvelopement of plants in

close vessels, appears to me to be owing to their abundant perspiration, nj.o|ja{,iy frpij,

which throws out the excremeutitious fluids, that are so fatal to them their perspira-

even in the open air, as to render a certain space among their neighbours ti"r^ "ot bein^

necessary to their vigorous growth. carried olF, . ,

which

QS *?UXRlTroN OF VSGETABtEb.

which appeared evidently to have been formed at the ex-
pense of water, and probably of li<^ht*,
Arpuments Geoloujlcal facts too seem to shake that theory, which as-

froin geology cribes the carbon found in vegetables to the small quantity

thaithfcavbon of carbonic acid contained in the atmosphere. How indeed

o!^ jlant>. does , . .

Ti jt come from can so small a portion of this acid, scarcely amounting to a
• atmos- ^pj^ thonsandth part of the air, explain the formation of those
vast mines of pitcoal, which still retains the marks of those
organized substances whence it originated, and the organic
origin of which is sufficiently announced by its composition
of carbon, hidrogen, oxigen, and azote ? But without appeal-
ing to these ancient productions of the vegetable kingdom,
burled in the earth in such abundance, we need only cast an
eye on its surface, to satisfy ourselves that nature must have
taken other steps to produce carbon.

Charcoal pro- On the other hand, if, in the silent progress of vegetation,

duced from ^|^g elements of water concur with the solar light to produce
water, and . , • • i

therefore con- charcoal by mtmiate combmations unknown to us, charcoal

fains hidiogen. oug]^^ to contain hidrogen likewise; and this is confirmed by
experience.

Proofs of this. If charcoal strongly calcined be urged in the fire with a
substance that has an affinity for hidrogen, the charcoal is
partly decomposed, and hidrogurettcd products are obtained.

Light neces-

* To satisfy myself, that plants can appropriate to themselves the ele-
sary to the pro- nients of water, so as to constitute their different materials, only by their
duciion of car- own organic action combined with that of light, I caused a given quan-
bon in plants, ^ity of seed to grow in complete darkness, and at the common tempera-
ture of the air. They shot out long white filaments, at the extremity of
v/hich were the two seminal leaves; but nothing more appeared. After
desiccation these plants weighed less than the seeds whence they sprung :
which appeared to be owing to their having lost carbon in this languisli-
ing state, instead of acquiring it,
A re tl ♦ "t ^"^ ^^^ mode of action of light on vegetables remains yet to be known,
combines with It appears however, that it enters into combination with them, and that
them. to this combination is owing the green colour of their leaves, and the va-

riety of hues admired in their flowers. Yet Mr. Humboldt has found
green plants growing in deep and dark mines, the atmosphere of which
contained a great deal of hidrogen. Does not this fact indicate some-
Perhap? ana- thing common between hidrogen and light, particularly when we ob-
logous with hi* serve, that these two fluids, the lightest in nature, seem likewise to pro-
rogen. ^^^^ analogous effects on some metallic oxides and salt ?

Mr.

NUTRITION OF VEGETABLES.

27

Mr. Bcrtliollet mixed 30 gr. [463 grs.] of charcoal cal-
cinefl In a forge fire with 20 gr. [309 grs.] of sulphur, and
by distillation in a porcelain retort obtained more tlian 100
cuhie centim. [391 lines] of sulphuretted hidrogen gas : and
it appears to me to be probable, that, if the experiment were
frequently repeated with the same charcoal, it might be to- ^

tally decomposed, a fact that it would be interesting to
verify.

If oxigen in the state of gas be presented to the charcoal
instead of sulphur, water is formed, as is proved by the ex-
periments of Lavoisier on the combustion of charcoal, as
well as by those of ^Ir. Ilassenfratz : and analogous results
are obtainable with metallic oxides, according to the obser-
vations of Cruikshank.

It even appears from the nice investigations of Messrs, The diamond
Biot and Arrago on the refractive power of bodies, that the hidrcm,
diamond, which has hitherto been considered as pure car-
bon, must contain 'a large quantity of hidrogen, which has
the greatest refractive power of any substance yet observed
in nature. These gentlemen intend to verify their conjecture
by direct experiments, from which very interesting results
may be expected, The existence of hidrogen in the dia-
mond has been announced from other facts by Mr.Winterl.

From the chief facts that have been here mentioned it

follows : General con-

1 . That vegetables find in pure water every thing necessary
for them to assimilate.

2. Tliat vegetable mould in a state of complete decay
contains nothing soluble, and can only supply plants with i
water, which it retains abundantly in a certain state of divi-
sion adapted to their nourishment, ^

3. That vegetables can grow in any substance, provided it
have no action on them, and be perfectly insoluble in water.

4. That the organic powers, assisted by the solar light, de-
velopes in plants substances that have been deemed simple,
as earths, alkalis, metals, sulphur, pb.ospl.orus, charcoal,
and perhaps too nitrogen, that probably will no longer con-
tinue to be the limits at which chemical analysis will stop,

o. That oxigen, hidrogen, and tire appear to be the only

ekmea- ' ,

Jf^ ^ ON VEGETABLE MUCILAGES.

elementary substances, that serve to constitute the uhf.
verse.

6. Lastly that nature, in its simple course, produces the
most various effects by tlie slightest modiiicatioas in the
means it employs. '

** IV.

Oil Vegetahte Mucildges; by John Bostock, M. D. of
Liverpool.

Vegetable nui- J|_ lYE term mucilage is employed, in rather a va^^ue man-

cilage a vague ^,, ^ , „ ^,, i.-i-i

jgr^, ner, to designate a class ot vegetable productions, vvliich,

although they agree in many of their properties, are in other
The author's respects considerably dissimilar. My object in the follow-
object. jjjg course of experiments was to obtain a more accurate

knowledge of their peculiar properties, and. to discover tests
by which their presence may be detected, without having re-
course to those methods of analysis, in which they are re-
solved into their component elements.
Solution of Gum arabic, when dissolved in water, exhibits all the

gum arabic. properties of a vegetable mucilage in the most complete
form. I prepared a solution, in the proportion of ten parts
of water to one of gum, and to portions of this the follow^
ing reagents were respectively added; in general one drachm
of the solution was mixed with ten drops of the reagent, ex-
^ cept in the case of alcohol and the infusion of galls, when

^ . . equal parts were employed, 1. Acetate of lead, 2. super-
Examined > ,.-, ^^ • /»• • -^
^iih different acetate 01 lead*, 3. mtro-muriate ot tin, 4. nitro-muriate of

reagents, gold, -5. nitrate of mercury, 6. oxysulphate of iron, 7. sili-

Their effects. ^'*^^^^ potash, 8. alcohol, and 9. infusion of galls. In No. 1,
there was a copious, dense, white precipitate. No effect
was produced in Nos. 2, 3, and 4. In No. 5 a white preci-
pitate appeared, which was dissolved by agitation, but was
reproduced by thcaddition of water, and in a few hours it
assumed a light pink colour. In No. 6 an orange coloured
precipitate was formed, at first in small quantity, but in 24

• For the difference between these two salts see Nicholson's Journal,
XI, 7b', und Thoa.sai/> Chemistry, Hi, 2G2, (^3d Edit J

hours

ON VEGETABLK MUCILAGES. S9

hours'' the whole became opake. In No. 7 an immediate
opacity was produced, and after some time a precipitate fell
down. There was an immediate precipitate in No. 8 : but
in No. 9 there was no effect produced. If the oxysulphate
of iron be added to a solution containing -g- of its weight of
gum, the whole is immediately converted into a solid, trans-
parent, orange coloured jellvi; When the solution is so far
diluted as to contain only a" thousandth of its weight of
gum, alcohol no longer produces any visible effect ; while a
strong solution is immediately converted into a white, and
perfectly opake fluid.

A substance which, in its physical properties, bears a Cherry tree
strong resemblance to gum arabic, is the gum which exudes fljfJrently br
from the cherry tree ; but I found the effects of reagents reagent*,
upon it to be considerably different^ When the acetate of
lead is added to a mucilage of cherry gum, there is no pre-
cipitate thrown down, but there appears a slight tendency
to coagulation, and in the space of 24 hours the gum ap-
pears to be separated from its solvent in the form of tine fila-
ments. The nitro-rauriate of tin converts the mucilage into
a solid jelly of a light yellow colour; the oxysulphate of
iron causes no precipitation or coagulation, but changes th-e
colour to a blackish brown ; the nitro-muriate of gold causes
an immediate opacity, and changes its colour to a light
brown, but there is no precipitate thrown down ; the super-
acetate of lead and the nitrate of mercury produce no effect.
When alcohol is added to a strong solution of cherry gum. Part of its so-
a number of filaments are formed, but the erreatest part of ^"tion incorpo-
,, ., , . i. VI XT- 1 1 1 • 1 rates with alco^

the mucilage seems to mcorporate with the alcohol without hoi,

undergoing any alteration ; the solid gum is not, however,
in the slightest degree soluble in boiling alcohol. The in-
fusion of galls produces no effect upon the mucilage of
cherry gum. The cherry gum, when first dissolved in water, Separates from
forms a uniform and transparent solution, but after being water by stand-
kept for some days in a warm atmosphere, it gradually ex- *"^*
hi bits a tendency to separation, a number of dark films are
formed in it, which rise to the surface, and the whole be- *^

comes slightly turbid *,

* The result of my experiments on cherry gym will be found to differ
very considerably from those of Dr. Thomson. Chem. V, 48.

Tragacanth

30 ON VEGETABLE IHr( It.AGKS.

Tragacanth. Traj^acauth is, in many of its physical properties, consi-

derably dift'erent iVom gum arable, and its habitudes with
the chemical reagents appear to be^o less dissimilar. Wn-
ter dissolves this substance with so much difificulty, that it
hea been said to be absolutely insoluble f. When traga-
canth is digested in water, it absorbs a large quantity of the
fluid, and is greatly increased in bulk, but even after being
kept for sorrie time at the boiling temperature, no proper
When soften- solution seems to be produced. If, however, the tragacanth
in water' m^y ^" *^'^ softened state be strongly rubbed in a mortar with an
bedis-:o]ved by additional quar^tity of fluid, a real combination appears to
tnturutiun. -^^ effected ; a mucilage is formed, which possesses a homo-
geneous consistence, and retains the same state for several
weeks, without manifesting any tendency to subsidence. A
1 part to If^O: >jjy(.j|jjp.g ^f ^\^\^ kind was made with I part of trao-acantlr

equal to 10 of ^ . ' ^,

gum arabic. ^^ 100 parts oi water; it was of about tne same consistence

with that composed of 1 part of gum arable to 10 parts of

water. To this mucilage the same <J reagents were added

Effects of rea- as in the former experiments. In No. 1 a copious dense

gents on t xe precipitate was instantly produced. In No. 2 there was a
solution. ^. ^ " .

slight degree of coagulation, and a precipitate, which was

increased in the space of 24 hours. In No. 3 a firm coagu-
lum was instantly formed. No elfect was produced in No.
4, except the mucilage was extremely dense, when its colour
was changed to a dusky gray, and afterward to a blackish
purple ; but without any precipitation or coagulation. lu
. the same manner the oxysulphate of iron produced no ef-
fect, except the mucilage was of a very strong consistence,
when its colour was changed to a deep brown; but there was
no precipitate or coagulum. The nitrate of mercury threw
down a slight precipitate of a reddish tinge. Silicated pot-
ash produced HO efl'ect, except a very strong solution was
employed, when there was a degree of opacity produced;
bat the same was observable upon the addition of caustic
potash. It was difficult to asce-.tain the elfect of alcohol
upon tragacanth, because, however ci»refully the mucilage
JL greater per- was prepared, any farther addition of fluid would not incor-

tion of fluid uofate with it, but produced un aiipearance of precipitation.
, "would not in *

♦ Duncan^- Dispensatory, p. 182. Thoi*:-ou'» Chemistry, V. 46.

In

ON VEGETABLE MUCII-AGES. g]

In this case, however, I conceive that a proper precipitate corporate with
WHS formed, because a greater decree of opacity was percep- ^^'
tible, upon the additiun of alcohol to the mucilage, than
from an equal quantity of water ; and «^fter remaining for
some time, the effect was evidently increased, the solid mat-
ter being separated in a liocculent form. A turbidness was
produced upon adding the infusion of galls to the mucilage
of tragacanth, biit the same difficulty occurred in determin-
ing whether there was any speciiic effect produced by trie iStH^y
presence of the tan. I did not tind tragacanth to be preci-
pitated by the sulphate of copper, as stated by Dr. Dun-
can*.

A well known vegetable mucilage is extracted from lin- ^^ucilsge of
seed. By adding a quantity of the seeds to 10 times their
weight of water, a fluid was procured of about the consist-
ence of the abumen ovi ; when poured from one vessel to
another it showed the same tenacity with the mucilage of
gum arable, and it also resembled gum in being indefinitely incorporates
soluble in water, and in immediately, incorporating itself ^^^''^^^^^'^^^k®
with any additional quantity of fluid. Its chemical properties . '
are, however, considerably different from those of gum, its chemical
Upon the addition of the acetate of lead a copious, dense propemes.
precipitate was immediately thrown down ; with the super- , *^^

acetate of lead, and the nitro-muriate of tin, there was a
considerable opacity ; with the nitrate of mercury a slight
precipitate only was formed; while the nitro-muriate of gold,
the oxysulphate of iron, and silicated potash, produced no
effect. When equal parts of the mucilage and alcohol were
mixed, the fluid became slightly turbid, a degree of coa^^u- ^

lation was produced, and at length the solid matter was se-
parated in a flocculent form. Linseed mucilage is not pre-
cipitated by tan.

A substance, which in its physical properties, and in the Mucilage of
manner in which it is procured, bears a strong analogy to quincesecd.
the linseed mucilage, is that^erived from the seeds of the
quince. A quantity of these seeds, boiled for a few mi-
nutes in 40 times their weight of water, produced a fluid of
about the same consistence with the linseed mucilage eai-

♦ Ed. Dispensatory, p. 183, »

ployed

32 ON VEGETABLE MUCILAGES.

-m

ployed in the last experiments. When poured from one

vessel to another, it exhibited tlie same deoTPo of tenacity ;

when recent it was perfectly homogeneou^', but after being

kept for some time, it shoM'ed a tendency to coagulation. It

Coagulated by was submitted to the same reagents as in the former experi-

most of the re- ^ j -.t i, ^ t , . . ,

agents. ments ; and with all of them, except the sihcated potash

and the galls, the efiect produced was a greater or less de-
- ^ gree of coagulation. With the acetate of lead the coagu-
1^ lation was so considerable, tiiat the solid matter was in-
stantly precipitated in the form of dense white flakes; the
eft'ect was equally rapid with the nitro-niuriate of tin, but
the coagulum was not in quite so dense a state. With the
superacetate of lead, the nitro-muriate of gold, the nitrate
of mercury, and the oxysulphate of iron, the coagulation

Coagulable by was less complete, although sufficiently a|>parent. As the
quince niucilage is coagulated by the mere addition of an
acid, it is probable, that the effect produced in these cases
may depend in some degree upon the acid, which enters

but this does iwto the composition of these metallic salts ; yet the action

rot account ^f j-j^^ acetate of lead and the nitro-muriate of tin were so
for the effects. . .

remarkable, as to indicate the operation of a specific affi-

Tiity. It may be farther observed, that a greater effect is
produced by the acetate of lead, than by the super-acetate,
although in this latter salt there is a portion of uncombined
acid. The effect of alcohol upon the quince mucilage was
exactly similar to that upon the linseed.
Hyacinth roots The bulbous roots of many vegetables are composed in a
great measure of mucilage, upon which I proposed to make
my next experiments, and for this purpose I selected the
hyacinth. Some of the roots of the common blue bell*,
were bruised in an earthen mortar, and afterward rubbed
with four times their weight of water. The whole was con-
verted into a pulpy mass, which was strained through linen,
and then appeared homogeneous, although opake. In a
few hours a substance of a farinaceous appearance separated
from it, and left the mucilage more transparent. It was
now filtered through paper, and w as in appearance and con-
sistence very similar to the mucilage of linseed; although it

* Hyacinihus non sciiptus of Withering, scilla nutans of Smith.

* ' ^ differed

ON VEGETABLE MUCILAGES. 33

differed from it in soon showing a tendency to putridity. Their muci-
wben it exhaled a very nauseous odour. The reagents used pufreStion!*
in the former experiments were employed in this case. The Xfsted with
acetate of lead formed a dense precipitate, composed of the reagents,
white fdms and flakes; the super-acetate of lead threw
down a precipitate in moderate quantity ; the nitrate of mer-
cury a precipitate of a light pink colour ; the nitro-muriate
of tin a copious white precipitate ; the nitro-muriate of gold
u liglit brown precipitate ; the oxysiilphate of iron a brown ^'R*

precipitate; the infusion of galls also formed a precipitate;
while the silicated potash produced no effect *.

After having- examined the properties of six species of Experiments
mucilage, I next turned my attention to some bodies, which sub^tancfs*"^
although obviously different from the mucilages, yet seem
to have a close connection with them in their origin and con--
stitution. The first of these is starch. A quantity of it Starch,
was boiled in water, until it had acquired that state of half
solution, of which it is alone capable, and in this form it
was subjected to the usual trials. With the acetate of lead
an immediate and very dense precipitate was thrown down,
aiid so intimate a combination formed between the lead and
the starch, that the water was separated from them nearly in
a limpid state. By the nitro-muriate of tin a very copious
precipitate was also thrown down, although less dense than *

tJie former; but no effect appeared to be produced by any
other of the reagents. It is not without considerable diffi- Effects of infu-

dence, that 1 venture to dissent from the opinion of Dr. f^o" ^^ t^»i o^-
rr.1 1 1 • p 1 • mg to the wa-

Ihomson, on tlie subject ot the action which takes place ter.

between tan and starch. When equal quantities of the mu-
cilage of starch and the infusion of tan are mixed together,
a precipitate is produced, which slowly subsides ; it disap-
pears by heating the fluid, and again becomes visible as it
cools. This process is described as a characteristic property
of tan ; but 1 have observed the same appearance to ensue,
if an equal quantity of water be added to the starch muci-
lage, it appears to depend merely upon the insolubility of
starch in cold water.

The effects produced by the reagents upon paste, made Flour past«.

* These results differ from those of le Roiix. Ann. Chira. 145 S: seq.
Vol. XVIII—Sept. 180(t. D by

S4 oif Vegetable mucilages.

by boilins^ flour in water, were somewhat different from those
upon starch. The acetate of lead and the nitro-muriate of
tin produced, as in the former ease, very copious precipi-
tates ; the nitrate of mercury caused the fluid to assume a
pink colour, and the nitro-muriate of gold a dusky gray, but
without any precipitate; the super-acetate of lead, the
oxysulphate of iron, the silicated potash, and the infusion of
reagentt qot ea- galls had no visible effect. It is necessary to observe, that
sily observable, in the experiments upon starch and paste, the substances
themselves being opake, it is difiicult to ascertain the effect
of reagents upon them, unless it be considerable and im-
mediate.

As starch and paste differ from each other principally in
Gluten. consequence of a quantity of gluten which exists in the lat-

ter, 1 thought it necessary to obtain this substance in a sepa-
rate state, in order that its properties might be examined
with more accuracy. I accordingly procured it in the usual
manner, and digesting a quantity of it for some days in
solved. water, it exhibited marks of partial solution. The fluid was

then filtered, and appeared homogeneous, although some-
Effects of the what opake; in this state it was submitted to the reagents.
reagonts. Precipitates were thrown down by the acetate of lead, super-

acetate of lead, and the nitro-muriate of tin. With the ni-
trate of mercury a precipitate was produced in moderate
quantity, which very quickly subsided, while the fluid as-
sumed a beautiful pink hue. With the oxysulphate of iron,
and the nitro-muriate of gold, precipitates were also thrown
down, the latter of a light brown colour. No effect was pro-
duced by silicated potash ; but a very copious precipitate
ensued ujion the addition of the infusion of galls.
V t ble ' I- ^ i^ext wished to ascertain the properties of vegetable
ly. J€lly» 8nd for this purpose I procured a quantity of it from

Prom the the oulp of the gooseberrv. I could not, however, succeed

gooseberry. .*..., -'i i • i •

N tf^ li from ^" freeing it from the acid which it contains, and was, on

acid. this account, prevented from observing the operation of the

metallic salts and the silicated potash. I found that a pre-

^In?''^^^^'^ ^^ cipitate was formed by adding the infusion of gall to it.

I next submitted a strong: solution of sua^ar to the action
Sugar. , . .

of the difterent reagents, but I found that no effect was pro-
duced in any of them, except the acetate of lead, which nfter

some

ON VEGETABLE MUCILAGES. c35

some time became opake; but as thisi effect is produced
merely by adding it to water, when exposed to the atmos-
phere, I was inclined to suppose, that the effect was produced
independently of the sugar. . , .-

These bein«: all the substances to which I bad an oppor- General coh^
„ ,. . ^ T ^ • • clubions.

tunity ot extending my expernncnts, 1 must now mquire r

whether any general conclusions can be deduced from them.
And first, as to the value of the different reagents employed
as tests. The acetate of lead is by far the most delicate and Acetate ef ' •
copious in its effects, but it can be of little value in discrimi- ^^'"^^ ^^^ ^^^^^
nating the different species from each other, because it- prq- notdisciimina-
duces its operation almost equally on all of the.a. With t'^^-
respect to the super-acetate of lead, we may in the first The superace-
place remark how materially it differs from the acetate, with ^^^^greutf ^^^^
which, until lately, it was confounded. The acetate of lead
was affected by all the substances to which it was applied,
except sugar; while the super-acetate* produced no change
upon gum arabic and starch, nor had it any specific effect
upon quince mucilage; it was affected only in a slight de-
gree by tragacanth, while with the linseed and hyacinth my^
cilage, and with gluten, tolerably copious precipitates weFe
thrown down. The nitro-muriate of tin does not act upon xt-
gum arabic, but is more or less atiected by every other kind fj/tin.
of mucilage, particularly by those of cherry gum, tragi\^
canth, and quince, and by starch of gluten. We have sven
in how peculiar a manner the oxysulphate of iron acts.,i|po'n Oxysulphate
^um arabic; it produces a brown colour in a strong solution of 'ron.
iif tragacanth ; and it forms a precipitate with th^^ hyacinth
and the gluten ; the quince is, as usual, coag\;}ated ; while
no change is effected on the linseed or t\^e starch. The
nitro-muriate of gold is precipitated by ^ayacinth mucilage ^'gold?""***^
and by gluten; the quince, as in other cases, is cqagulated
by it, but its most remarkable effect \s upon the tragacanth,
the colour of which it converts to a ^'^ep blackish purple.

The nitrate of mercnry throw ^ down a precipitate of a sin- ...
T ^ X' u- ' . . Nitrate of ai#r-

gular nature from gum arab .p, and tinges the fluid of a pink cury.

colour; the same shade is. produced iu the tragacanth, the

* Dr Thomson raust^ no doubt, have employed this suit, when he
:itates, tliat the acetat'^Q^jead does not precipitate gum.

£> ^ hyacinth

;d6

ON VEftF.TABLE MUCILAGES.

Silicated pot
ash.

Tan.

AloohQl.

Nitric acid.

hyacinth mucilage, and in the flour paste, and still more re-*
inarkably in the ghiten ; there is a slight precipitate in the
linseed, and a coagulation in the quince, but no change of
colour. The silicated potash acts only upon gum arable, and
points out its presence when it exists only in a very minute
quantity. Tan does not act upon any of the mucilage^, ex-
cept in a slight degree upon tragacanth ; it is copiously pre-'
cipitated by gluten, and also by vegetable jelly. The eifects
of alcohol have been fully stated. Gum arabic it precipitates
from the water in such a manner as to render the fluid com-
pletely opake ; whereas in the linseed, quince, and traga-
canth mucilages, the solid matter was separated in a fibrous
form; with the hyacinth mucilage both the pulverulent and
fibrous kinds of precipitate were produced ; while the cherry
gum was only slightly affected by it. Alcohol precipitated
starch in the same manner that it did gum arabic,

The action of the nitric acid on the different mucilages
was so similar, as not to exhibit any phenomena, which can
assist us in distinguishing them from each other. Accord-
ing to the circumstances of the process, either the saclactic
acid, or a mixture of this acid and the oxalic was produced,
attended with the usual disengagement of gas. It did not
appear, that any use can be made of the sulphuric acid as a
test of the differejit mucilages ; I put in practice the process
mentioned by Ilermbstaedt, for separating gum from muci-
lage, but in no instance did 1 perceive the coagulation whieh
he describes. The acid, in a concentrated state, slowly dis-
solves the different mucilages, and forms with them a thick,
black fluid. I did not observe any effect to be produced by
Neutral sajts. the addition of the neutral salts, except that many of them
Alkalis coagulated the quince mucilage. The pure alkalis gene*

rally rendered the mucilages more fluid, but they did not
exhibit any specific or discriminating effect,

. _ . Before we attempt to make any arrangements of the ve-

Arrangfiment ^ •■ ^ , ■^ ~

of the vegeta- getable mucilages, it is necessary to inquire, whether the
lie mucilages, different varieties are to be considered as all of them homo--
geneous, or whether at least some of them ought not to be
regarded as compounds of two or more of the primary niuci-
Some of the ^^r,^^' Although I am not acquainted with any method, by
compounds, which the constituent parts of the compounds can be sepa^

rated

Sulphuric
acid.

ON VEGEtABtir MUCtLAGES* 3^

VAted from each other, yet I am inclined to believe, that this
is the case; and we may conjecture, with some degree of
plausibility, that thbse species are the most simple, that are
acted upon by the fewest reagents. In the first place 1 con-
sider gum arable ti:> be ft homogeneous substance ; and we h'^j^cge^ieous
may pro[.erly assign to it the specific name of gum, to which • nd gum by
it is entitled by long usage and general cons<^nt. Its preci- ^'^^ of emi-
pitation by silict»ted potash, and the orange coloured jelly
which it forms with the oxysulphate of iron, are sufficient to ^ aracters.
constitute its essential characters ; to which may be added
the milky precipitate which is formed by the addition of
alcohol to it, and the negative circumstance of its not being
affected by the nitro-muriate of tin. I am disposed to re- •> >

erard as pure veffetabie mucus the substance procured from *r .1.1

'-; "^ . o . ^ ^ V egetable mw

hnseed. It is sufficiently characterized by the effect of the cus from Un-
superacetate of lead and the nitro-muriate of tin, and by ^^^^•
the manner in which it is precipitated by alcohol from its
aqueous solution ; these circumstances, as well as the nega-
tive operation of the oxysidphate of iron and the silicated
potash, serve to mark an obvious distinction between this
substance and gum. A third vegetable principle, which is
possessed of pecular physical properties, is starch. In its starch,
relations to the different chemical reagents it strongly re-
sembles mucus, although it differs from it in the manner in
which it is precipitated by alcohol. Gluten is a fourth sub- Gluten.
stance, in every respect essentially different from any which
we have hitherto examined. The most remarkable effect
produced upon it, by any of the chemical reagents, is the
change of colour induced by the nitrate of mercury, and the
copious precipitate by the addition of tan.

In endeavouring to form an arrangement of vegetable
mucilages, and to assign definite characters for the primary ^x*^"^ °^ ^"^''
substances, which enter into the composition, we must con-
sider to what degree of minuteness our subdivisions ought
to be extended. If, for instance, we meet with a body,
agreeing in every physical and chemical property witli gum
arable, except that it is not precipitated by silicated potash,
are we to regard this as a distinct vegetable principle, or sim-
ply as a variety of gum ? This latter opinion I should cer-
tainly be inclined to adopt ; for by indefinitely multiplyino-

Qur

38 ^^ VEGETABLE MUCILAGES.

our principles, we should defeat the very end of arrangement.
Hence, in the formation of our essential characters, we must
epdeavour to adopt the due jnedium between the extremes
of minuteness and. laxity. In each particular instance we
must be guided by those propertied, which are the most dis-
dinctly recognized, and the most readily ascertained, and
which exliibit the closest analogy to each otlier. Under this
impression I shall not think it desirable, 'm tJie present state
of our knowledge, to proceed any farther in proposing an
additional number of primary vegetable compounds ; but 1
shall offer a few remarks upon the different mucilages, that
have been made the subject of experiment.
Generic clia- Gum T consider as a generic term, which may be defined
meters of gum. a transparent, brittle, insipid substance, indefinitely soluble'
in water, with which it forms a mucilaore; the mucilag^e is
precipitated by alcohol, in such a manner as to render the
fluid perfectly opake ; it is also precipitated by the acetate
of lead in dense flakes. Under this genus we can, at pre-
Species and sent, rank only one species, viz. gum arabic, to which the
following specific character may be applied. A gum, the
mucilage of which may be precipitated by silicated potash ;
forms with the oxysulphate of iron a solid jelly, with the ni-
trate of mercury a precipitate of a pink colour; and is not
acted upon by the superacetate of lead, the nitro-uiuriate of
tin, or the nitro-muriate of gold.
Generic cha- The second genus is mucus, a substance seldom found
racters of mu- in a separate state, but forming a frequent constituent of the
seeds, roots, leaves, and other parts of vegetables. It is
indefinitely soluble in water, and forms with it a mucilage ;
this is precipitated by alcohol in a fibmus form, without ren-
dering th€ fluid opake ; it is also precipitated by the acetate
of lead, the super-acetate of lead, and the nitro-muriate of
tin.. Under the genus of mucus we may enumerate three
Three species. ^P^pi^s, that of linseed, of quinceseed, and of the hyacinth.
To the first of these the generic character strictly applies ;
Specific cha- ^*^ to the second we maj^ add the specific character of being
racters. Qpagulated by the addition of any acid, neutral, earthy, or

That of the metallic salt. The hyacinth mucilage I have also classed as
hyacinth a ^ mucus, because its leading properties are such as point
out its relatioji to the substances of this genus. In the state,

however,

ON VEGETABLE MUCILAGES* - 39

liow6Vcrr, in which it is usually procured, it seems to be a
compound of two or more of the \«e,^et able principles. A
quantity of starch is obviously mixed with it ; and I am in-
clined to think, that it also contains gluten, a supposition
which will account for all the phenomena it exhibits with
the chemical reagents.

There are two substances, the characters of which still Cheny gum,
remain to be ascertained, cherry gum and tragacanth. From
its physical properties we should be disposed to place cherry
gum in the same class with gum arabic ; but it is so differ-
ently affected by the chemical reagents, as absolutely to pre-
vent us from considering it in this point of view. Its pro-
perties are not more characteristic of mucus ; nor does it af-
ford any indications of being a compound substance, so that it
may probably be necessary to consider it as a distinct veget-
able principle. The action of the acetate of lead and of al- tinci^principle*
cohol upon cherry gum would induce us to suppose, that it
bore an analogy to sugar, rather than to the gums or mu-
cuses; but the effect of the nitro-muriate of tin is not fa-
vourable to this supposition ; nor is that of the nitric acid,
which I found, by the usual process, converted it principally
into the saclactic acid. If we are to bestow a new name
upon it, we might denominate it cerasin. Cerasin.

I am equally unable to determine in what class traga-
canth ought to be placed. It has obviously no relation to Tragacanth.
gum, either in its physical or chemical properties ; and it
differs very considerably from what has been laid down as
the generic character of mucus. Its properties are the most
similar to those of starch and gluten ; particularly to that
form of starch, which is prepared by first forming it into a
mucilage with hot water, and then evaporating it to dryness,
when it becomes transparent and brittle, but almost insoluble
in water. The effect of the nitro-muriate of gold forms a
remarkable character of tragacanth mucilage ; it seems to
depend upon a partial reduction of the oxide, at the same
time that it unites with the tragacanth. The effect was very
evident when the solid matter composed 1-50 part of the
fluid, but if much more diluted, it was not perceptible ; a
slight degree of the same effect is produced when the nitro-i
muriate of oold is added to flour paste.

I am

40 ^^ SULPHUROUS MINERAL WATERS.

I am fully sensible, that I have by no means executed the
I task, whieh 1 proposed to myself, of charactevizin}^ and ar-

ranging the vegetable mucilages ; but a particular circum-
stance having, for the present, put a stop to my experiments,
I was induced to publish this very imperfect attempt, in
hopes, that the difficulties being pointed out, some more able
hand may endeavour to remove them.

Liverpool^ Aug. l'2ylS07.

y.

Observations on Sulphurous Mineral Waters; 7jy Mr,
Westrumb*.

Sulphurous i-vAR. Westrilmb has examined various sulphurous waters,
hidr'uf^hu^"^ and lately those of Eilsen in the county of Schanmbourg,
ret of lime. One of the most interesting facets he has observed is, that
all stilphuroits waters contain more or less hidrosulphuret
of lime.
Thp gasses be- '^^ detect this he boiled the mineral water, excluding the
ing expelled br contact of attnospheric air, to expel the sulphuretted hidro-
shown by sul- g^" g^^ ^"<^ carbonic acid. Into the water thus boiled he
phuric, nitric, poured sulphuric acid, when more sulphuretted hidrogen
' gas was evolved, and sulphate of lime was thrown down :
fuming nitric acid, which separated from it sulphur : and
oxalic acid, which expelled sulphuretted hidrogen, and
formed oxalate of lime. The water evaporated in open ves-
sels let fall sulphate of lime, and gave out sulphuretted hi-
drogen ga.8*
M tl d f '^^ ascertain the quantity of sulphuretted hidrogen gas and

certaining the carbonic acid, Mr. Westrumb proceeded as follows. He in-
**hureuld^7ii ^^o^luced the sulphurous watet into a matrass, till it was fil-
drogenandcar- led to a certain point, which he marked ; fitted to it a curved
fnlhem '"^ «*^ tube, which terminated in a long cylinder ; filled this cylin-
der with limewater for the one experiment, and with acetate
of lead with excess of acid for the other; luted the apparatus ;

* Driginally published in Gehleii's new Journal of Chemistry, and
abridged by Vogel, Aimales de Chimie, vol, Ixii, p. 183, May, 1807.

the

ON SULPHUROUS MINERAL WATERS. , 41

unci boiled the water till noniore gas was expelled. When the
liniewater is used carbonate of lime is precipitated in the pro-
portion of 20 grains to every 10 cubic inches of carbonic acid
gas ; when the solution of acetate, hidrosulphuret of lead is
thrown down in the proportion of 19 grains to 10 cubic
inches of sulphuretted; hidrogen gas;

Another observation, not less remarkable, relates to sul- Sulphuretted
phuretted nitrogen gas. "'^''^S^" g^'

It is known tliat Dr. Gimbernat, a Spanish chemist, as- ''^ the waters of
sells, that the thermal waters of Aix-la-Chapelle contain snl- ^^
phuretted nitrogen gas, Mr. Schaub too says, that he has
obtained it from- tlie sulphurous waters of Nenndorf in and Nenndorf.
llesse. The following characters are ascribed to this gas. j^g chaiacters.
1. In smell it resembles sulphuretted hidrogen. 2. It is not
decomposable by carbonic acid. 3. It is not inflammable.
4. It will not maintain combustion. 5. It is not decom-
posable by nitrous acid. 6. It is not decomposable by con-
centrated nitric acid, which separates from it sulphur. 7. It
decomposes metallic solutions, and forms sulphurets. 8. It
has a great affinity for water, from which it is separable only
by long boiling.

But Mr. Westrumb has found, that sulphuretted hidrogen Sulphuretted
gas, when washed with milk of lime, or passed through lime j^^s the*^ ^^*
diluted with water, acqu'nres all the properties here men- properties im-
tioued. Whether the sulphuretted hidrogen gas be obtained P^'^^'^*^ ^o ^^ ^Y
from sulphurous waters, or prepared artific.ally, the same
phenomena take place. If the milk of lane be taken from
it by an acid, sulphuretted hidrogen is disengaged, which is
inflammable, and possesses the usual properties. Sulphu-
retted nitrogen gas. tlierefme is a product of the operation.
Mr, Westrumb however is in doubt, whether this new gas be Whether a
produced by the action of^quipklime. on sulphuretted hidro- product or an
gen, or whether the sulph\^retted hidrogt^n gas contain sul- ^ "*^' ^^^^ '
phuretted nitrogen.

A third observation, not less interesting, is the presence Carbon in sul
of carbon and carburetted substances in sulphurous mine- [,,J.g'^°"* ^'*"
ral waters. ., ^; , , . . '

Mr. Westrumb^has jdiscovered in them & new principle, a A fetid resin of
fetid resin of sulphur fslinkendes. schwefelharzj. To ob- la'them.^"'""*
tain this, the sulphurous wuteu laust be evaporated in open

vessels

'^ OS SU^rHUROUS MINERAL WATERS.

rt'ssels, and the residuum dissolved in alcohol, which thlces

up tliis resin and the earthy muriates. By evaporating tlie

alcohol, this substance apy)ear8 at Hrst as a yellowish fat,

'which jwradually assumes a brown colour, and becomes resin-

^\\s. By repeated solutions in alcohol and evaporations it is

decomposed into sulphur^ and h blackish bronn resiii; It

^ ,, ... emits a earlic smell ; which becomes very strono;, and similar

Smells like ", ' -i -n . .

garlic. to that of assatetida, if water be poured into the alcoholic

solution. Its solution acts as an acid.

The resin is soluble in ammonia, and communicates to it

monia. «i yellow colour. This liquid comportsiitseJf Ike that of

Vorms hidro- ^^o^^"* With timewater a hidrosulphuvet is formed. All

sulphurets. the&'e sollltions act ou metallic compounds in the «ame man-

•li'^r'ks sulphuretted liidrbgeri. "

As sulphurous milieral waters arise from strata of pltcoal,

th^e bitumen of i^^i'^i^ps the source of this bituminous principle may be

coal. traced to the coal itself. ' '

„, , , c '' "Rouiid the baths' of Eilsen, as round those of St. Amand,
Black mud of , ...

the baths of k mud accumulates, which in time grows darker coloured,

Eilsea. ^^^ ultimately black. From this are obtained, on analyzing

it, fetid sulphurous resin, hidrosulphuret of lime, sulphur,

lime, alumine, magnesia, charcoal, an<i sand, with some fi-

' brous substances;' and a little sulphuretted hidrogen gas,

• • •'' 'i and carbonic acid gas. » ■

' ' ",■,, Whatever maybe the origin of the bituminous principle

Charcoal- afid . , ^ , . -« r ^xr .l i • i i T»/r

the fetid resin m the sulphurous waters, Mr. W estrumb, assisted by Mr.

produced from Basse, has been able to produce charcoal and the fetid resin
f>u P ^^- |-j.Q^ py,.g sulphur. For this purpose he has digested in al-

cohol sulphur precipitated from sulphuretted hidrogen by
an acid. On distilling off part^of the alcohol, sulphur is se-
parated in yellow crystals, or in a yellowish gray powder.
The fetid resin is then completely formed in the superna-
tant liqtibr, and possesses aU the properties mentioned
above.
Not formed b^' Its formation may be ascribed to the concurrence of the
the alcohol. alcohol,* particularly as after its separation from the resi-
duum left on evaporating sulphurous water, the pungent
^mell iiS ipanifested on its being taken up by alcohol. But
eeveril observations lead Mr: WestrUmb to believe, that,
'alcohol does not contribute to the formation of this sub-
stance.

ACTION OF SULPHUR ON CHARCOAL* S.$

stance, but rather that it dejives its origin from the sulphut

itself.

Messrs. Westrumb and Basse intend to pursue the inquiry, The inquiry

and promise to make known the results, ^'•^ ^^ P^J^r

^ sued.

VI.

Report on a Memoir of Mr. Berthoi.let, Jmm., entitled:
Inquiries concerning the reciprocal Action of Sulphur and
Charcoal; hu Messrs, Fourcroy, Deyeux, and Vaut

QUELIN*.

JLN 1796 prof*. Lampadius, of Freyberg, endeavouring to Lampadlus's

ascertain how much sulphur a martial pyrites mixed with sulphur alco-

charcoal would furnish when acted upon by fire, obtained a

very volatile sulphurous liquid, which he suspected to be a

compound of sulphur and hidrogen, and to which he after- hidroguretted

ward gave the name of sulphur alcohol. sulphur.

Clement and Desormes, unacquainted with this fact, when ^ , ,

» afterward endeavouring to demonstrate, that there is no hi- sulphur of CleV

c hogen in well burned charcoal, by passing sulphur in va- "™^"^ ^"'^ "

, r ,•• , , • 1 1 t' ■• i sornies.

p. our 'over very hot charcoal, obtained a product exactly si-

m ilar to that 6^ Lampadius. Having remarked, that the

ch arcoal in this operation was desti-^ye'd without evolving

anj ' gas; and that the liquid product, when burned, left

sora e slight black spots on the vessel that contained it;

thej ' thought, that this liquor was formed hj the combination

of su Iphur with charcoal, and consequently termed it carbu-

retted sulphur.

Thi's diiference of opinion respecting its composition in- Examined by
duced Mr. A. B. BerthoUet," to examine experimentally this Berthoile!,jun,
-question, with which rtiany interesting points in chemistry
are conn ected.

His ap 'paratus, which does not differ much from that of
Clement and Desormes, was constructed in the following |^^T.li'!!°r. ^^

o nib ^pp^rdlU::.

manner. A straight glass tube, about a yard long, was

Aiiiiales de Chemie, Vol. LXI, p. 127. Feb. 1807.

placed

^^ ACTiaN OF SULPHUR O^ CHARCOAL*

placed in a reverberatory furnace, so that one end projectecl
a little more than four inches beyond the wali of the fur-
nace; and the other end, which sloped gently upward, about
eighteen inches. The part within the furnace was coated
with a lute capable of sustaining a very strong heat. To
the lower end was fitted an adopter, terminating in a small
tubulated receiver, from which a curved tube passed into
water contained in a two-necked bottle. Another tube
with two bendings conveyed the gas from this bottle into a
pneumatic apparatus.
Charcoal in- Charcoal being included In that paft of the tube that was

cludea^m the juted, and sulphur introduced into the empty part, its up-
phur above it, per end was hermetically sealed; the tube was gradually
''"^ J^^* ^1'' heated to incandescence; and th^^ sulphur as it melted flow-

_, ,' ed down into the charcoal. When these came into contact.

Products. .

bubbles of gas were extricated, that succeeded each other

rapidly, and were accompanied with white vapours, which,
condensing in the adopter, passed into the receiver, and sunk
to the bottom of the water in the form of a white or some-
times yellowish oil.

^ , , , Mr. Berthollet however observes, that the results of this

These liable to . .. i ^ • , . ^

vary. Operation vary accordmg to a number ot circumstances,whicn

he has carefully described ; and the chemist not having it
always in his power to render these circumstances perfectly
similar, different products are frequently obtained.

If for instance the extrication gf gas and condensation of
that atfect Hquid slacken, the sulphur must be heated, that more rtiay
them. pass down ; and if this do not accelerate the operation, the

temperature of the charcoal must be increased. When th6
operator is desirous of producing much of the liquid, it is
necessary to i-aise the temperature of the charcoal a little
above a cherry red, and to allow only a slight excess of sul-
phur to pass down. Tod little df the sulphur prodiicea
only gasses, and a few drops of a liquid lighter than water^
which in the course of the process resumes the state of gas.
On the contrary, if the sulphur be too abundant, nothing
is formed but gasses, and solid hidroguretted sulphur, which
was mistaken for carburetted sulphur by Clement and De-

sornies. It is always iKjvantaeecus, to keep the vessels, in
The receivers " '^ * , , ,

which

ACTION OF SULPHUR ON CHARCOAL.

45

which the liquid is to be condensed, in a refrigerating ^^^^^^P^^*^' 5"
mixture.

In conducting the operation with these precautions, the Two stages in
extrication of gas will not take place after a certain time, tlie process,
unless both the temperature of the tube and the quantity
of sulphur be augmented.

The charcoal used by Mr. BerthoUet was always pre- Necessary pre^
viously heated for half an hour, to expel the water and gas- cautions.
€es that yield to simple heat. When the operation was
finished, he kept up the temperature of the tube, that the
nature of the residuum might not be altered by the sulphur
in contact with it; and for the same reason he prevented all
access of air to the apparatus, by turning a cock adapted
to the tubulure of the bottle.

On examining the products of the operation, stopped at ProductsoHh*
the end of the first stage, he found : 1. That the water in ^ *

the bottle, which was milky, had the smell and all the pro-
perties of sulphuretted hldrogen water. 2. That the gas
itself had a similar smell, dissolved in water by agitation or
long contact, and communicated to it all the characters of
sulphuretted hidrogen. 3. That this gas burned with a blue
flame, and diffusing a smell of sulphurous acid, 4. That
when mixed with oxlgen gas it detonated briskly with the
electric spark, sometimes without rendering limewater tur-
bid, but more frequently producing a slight precipitate, and
depositing sulphur.

From these characters every one must recognise in it sul- Evidently sul-
phuretted hidrogen; though Mr. BerthoUet found, that it P'l"'"^"^^ ^i-

1 111- ? .-1.1., . diogen,thougli

was less soluble m water than what is obtained by the ordi- little soluble

nary means. Scheele, Kirwan, and others, however, have ^'^ ^^^^^''•
mentioned combinations of sulphur and hidrogen, which
were little, if at all, soluble in water.

The liquid collected under the water in the receiver, and a liquid like
in the bottle, had perfectly similar properties to those de- ^^^*. '^^ '"^"^"
scribed by Lampadius, and by Clement and Desormes : ^*^^^"*'
that is, it was as transparent as water; it emitted a smell
resembling that of sulphuretted hidrogen, but more lively
and pungent; shaken in a phial with water, it adhered to
the glass, and rendered it greasy like an oil; and it burned
rapidly, with a blue flame, and smell of sulphurous acid.

He

46 ACTION OF SULPHUR ON CHARCOAL.

Left no char- He did not obtain any charcoal, however, as a residuum
bumed^^'^ of its combustion ; the circumstance on which Clement and
Desormes founded their opinion : for it burned entirely away,
or, if the combustion were stopped before it was completed,
left nothing but sulphur.
Its characters. This liquid, being very volatile, produces on the skin a
sensation of great cold. It dissolves in the air, greatly in-
creasing its volume; and then hums calmly with a blue
flame, and does not detonate by the electric spark. If wa-
ter be admitted to the air thus expanded, the air returns to
its original bulk, and the water acquires the properties of

EvHently con- guiphuretted hidrogen. This Mr. Berthollet observes would
tains hidrogen. „r„- m • • pi-i

of itself be sufficient to prove the existence of hidrogen m

the liquid.
Not entirely However transparent it was, he could never volatilise it

phur being entirely. Whether he left it exposed to the air, or assisted
^^ft. its evaporation by heat, he had always a residuum of sul-

phur, which he could sublime completely, without perceiving
any vestige of charcoal.
Thegassesit The residuum of this liquid affording Mr. Berthollet no

forded'^no indi- charcoal, he examined the gasses it produced, to ascertain
cations of char- its existence. But neither its combustion with oxigen gas
*^^^ * in vessels placed over water, nor the action of oxigenized

muriatic acid, nor that of alkalis, produced any indications
of charcoal, or of carbonic acid. In the first case the pro-
duct of its combustion did not render limewater turbid; in
the second nothing was found but sulphuric acid mixed
with muriatic ; and in the third a combination was obtained,
which comported itself like the hidroguretted sulphurets.
Tt'is therefore From all these facts the author concludes, that the liquid
sulphur" and ^ produced by the reciprocal action of incandescent charcoal
hidrogen. and sulphur is formed of sulphur and hidrogen, as Lampa-

dius announced.; and, contrary to the assertion of Clement
and Desormes, contains no charcoal. These facts at the
same time show, that sulphur and hidrogen, like many other
These unite in substances, are capable of uniting in various .proportions,
^^"^"'*^"'"P°''' according to circumstances ; and that the predominating in-
gredient always communicates some of its properties to the
compound. In the present case for instance, if the sulphur

ACTION OF SULPHUR ON CHARCOAL. 47

h€ very abundant, the compound takes the solid form : if which alter

. ,.11 ^ • 1 iu J.J. ^.• I"*, the characters

the proportion ot hidrogen be increased, the attraction ot its ofthecom-

particles is diminished, and it resolves itself into a liquid ; if pound.
a still greater quantity of hidrogen be present, the compound
expands, and the result is a gas.

Mr. Berthollet has made a very interesting experiment, The liquid
which greatly confirms this. The liquid in question, dis- ^'^^^'"^^^"^'^^
tilled with water at a temperature of 3G° [113° F.] afforded heat gave a
him a gas, that had the smell of sulphuretted hidrogen, burn- S^*»
ed with a blue flame, detonated briskly with oxigen when
fired, and combined readily with water, wliich it turned
milky, communicating to it the properties of sulphurous
water. After this gas a transparent liquor came over, swim- a light liquid,
ming on water, and wliich, as it evaporated on the contact of
air, precipitated to the bottom, or disappeared entirely, leav-
ing only some slight traces of sulphur on the water. At 45°
[133^] the extrication of gas Ceased, and a liquid heavier than aheavy liquid^
water succeeded. The colour and consistency of this liquid
increased, as the distillation proceeded.

On stopping the process when the temperature had been and a solid re-
kept some time at 45° [133°], what remains in the retort '"^'
becomes solid by cooling, and prismatic crystals are distiar*
guished in the mass. ' If a su<1icient quantity of sulphur be
not melted down on the charcoal, liquids of different den*? When the sul
sities are likewise obtained: the heaviest condense in the J^-^JJI^ J- ^^^j^^f
receiver ; the lighter do not condense, till they reach the different den-
bottle, where they rise to the surface of the water; and ^'^^^^ °^^^'"^*
lastly others, carried off by the gasses, reach the pneumatic
apparatus.

It is evident, that the efficient cause of these different mo- These modifi-
difications, depending on the respective qualities of the ^^'^'.^^°^''"^^-
elements that combine, is the difference of temperature, temperature,
which disengages first the most expansible bodies. This is
not peculiar to the compound of sulphur and hidrogen ; and
the effect is the move obvious, the greater tne ditlerence in
the expansive force of the substances.

The sulphur that flows into the adopter during the ope- The sulphur
ration contains a certain quantity of hidrogen, wiiich gives ^j^^^ flows by
it a laminated texture, an inferior density, and in particular contains hi-
a very decided smell of sulphuretted hidrogen, a small quan- ^^'^^sen,

tity

48 ACTION OF StirPHUR ON CHARCOAt.

tlty of which Mr. B^rthollet obtained from it by means of a

gentle heat.

but no char- But b}'' no method could he discover in it charcoal;

<^*^^'- thouffh he imacrined he discerned some very slight traces of

Some manga- i r • • r *i u i i-

nese and iron, manganese and or iron, arising irom the charcoal, or irom

The same pro- the sulphur itself. A fact long known, that confirms the

ducts when conclusions of Mr. Berthollet, is, that the same products

sulphurets are ™^y ^^ obtained by decomposing hidroguretted sulphurets

decomposed by means of acids, as by distilling sulphur over charcoal,

namely, sulphuretted hidrogen in the ^tate of gas, liquid

hidroguretted sulphur, and solid hidroguretted sulphur ;

and in all these substances there is no charcoal.

The charcoal On examining the charcoal remaining in the apparatus

notahered in after having been long exposed to the heat, Mr. Berthollet
appearance, r»i ici • x ■ t -,

but combined lound no external appearance oi alteration. It retained sul-

with sulphur, phur in actual combination, which heat could not separate,
but which might be dissolved by an alkali, or burned by
heating in contact with air. The charcoal is then very light
and friable, leaves fine black traces on paper, and burns
with difficulty. Charcoal therefore can combine with sul-
phur ; but this compound assumes neither the liquid nor
the gaseous state.
Charcoal con- All the facts adduced by Mr. Berthollet clearly demon-
tains hidrogen; strate the presence of hidrogen in charcoal, from which it is
inseparable by any heat we have yet been aVjle to produce,
which sulphur If sulphur take it from charcoal, it is by combining its che-
aidedby hear, jrj,it>al action with that of heat : and perhaps this may be a
takes from it. „ . . . , . • i /> i • i , ,

means oi depriving charcoal entirely ox hidrogen, and ob-
taining it in a state of purity, so as to describe its properties,
which from this observation may be yet unknown to us.
The whole of Mr. Berthollet has remarked however, that, when all the

the cliarcoal phenomena already described have taken place, if the tem-
may be made ' i ■ i i i f> i

lo disappear; perature be strongly raised, and a great deal of sulphur

caused to pass, the extrication of gasses recommences, and
the charcoaV may be made to disappear entirely. On stop-
])ing the process before this arrives, pieces of charcoal exhi-
biting evident marks of erosion will be found in the tube.
The little liquid obtained in this second stage of the process
is so volatile, that it soon reassumes the state of gas. The
sulphur that flows into the adopter contains no more char-
coal.

ACTION OF SULPHUR ON CHARCOAL. 49

c<t<il, than what passed at th<j commencement, but it contains
hidro^jen. An experiment made on a gramme [15| grs.] of
charcbal, previously heated for an liour in a for^e fire, con-
tinued five of six hoursj and produced four or five litres
[or wine quarts] of s^as.

This gas resembled sulphuretted hidrogen in its smell, and a gasems
manner of burning", solubility in water, and the properties ^^JljJ^^ j^i^^o-
it communicated to water. But water did not absorb it gen, and sul-
completely ; and the product of its combustion rendered ^^^^ *
limewater considerably turbid. In this gas therefore, ana-
logous probably to that which Clement and Desormes term'»
ed gaseous carburet of sulphur, the carbon subjected to.
the experiment is foand. It is ia fact a triple com-
pound of carbon, hidrogen, and sulphur ; requires for itsr ,
combustion nearly an equal bulk of oxigen gas ; and at
the moment of taking fire has its volume increased at least
tenfold.

With respect to the doubts, that may arise respecting the
natui'eof the precipitates formed in limewater in these expe-
riments, Mr. Berthollet gives means of ascertaining, whether
they be owing to sulphurous acid or carbonic.

Reflecting on the complete destruction of charcdafby the Somehkttogen

action of sulphur, and the nature of the products it furnishes, essential to

111- 1 1 ■, ■ • . 1 .r. charcoal,

we are tempted tobeheve, that charcoal is inseparable from

a certain quantity of hidrogen ; and that, at a high terape-

ratilre, the sulphur in contact with it occasions a new ordei* of

compounds, which assume the elastic state*

But on considering the quantity of gas obtained ^ and the The sulph'.:?
property sulphur has of retaining hidrbgen in the solid state, too probably
Mr. Berthollet suspected, that possibly the sulphur itself
furnished a certain quantity of the gas. To verify this in- Experiments
genious suggestion, he passed sulphur through a glass tubcj ^o prove ihis,
coated, and brought to a white heat ; adapted to it a tube,
for collecting the gas ; and obtained some very slight indi«
cations of sulphuretted liidrogen.

On the other hand, on iorming metallic sulphurets i^ From the for-
earthen retorts, after taking all possible precautions to re- mation of mo-
move every source of uncertainty, he obtained sufficient sul* ^^^''^ sulphu-
phuretted hidrogen gas to precipitate tlie solution of lead,
and to be set on tire. In these experiments he employed

Vol. XVIIi.— Sept. I8O7, E iroA

so

ACTION or SULPHUR ON CHAHCOAt.

Aqueous va-
pour passed
over mehed
sulphur takes
up hidiogeii,
■without being
decomposed.

General con-
clusions.

iron prepared expressly tor the purpose, copper, and mer-
cury. The last metal afforded him the most.

On this occasion too he repeated an experiment of Priest-
ley's,'who produced sulphuretted hidrogen gas, by passing
the vapour of water over melted sulphur r and he found,
that the water was not decomposed, for he could discover no
trace of sulphuric acid ; it only served therefore, to disengage
the sulphuretted hidrogen. Many other facts in confirma-
tion of these experiments might be adduced if necessary.
From the experiments of Mr. Berthollet we may conclude:

• 1. That charcoal contains hidrogen, which the most in-
tense heat we can produce will not completely expel.

' 2. That sulphur at a red heat acts upon hidrogen, and
forms compounds in very different proportions, on which
their propertit s depend.

3. That charcoal deprived of hidrogen, or at least nearly
so, forms with sulphur a solid compound, into which the
sulphur-enters in a small proportion.

4. That at a high temperature sulphur, carbon, and hi-
drogen unite into a compound, which assumes the state of
gas.

5. And lastly, that sulphur contains hidrogen.

Experiments
by Robiquet
confirm those
of Berthollet.

Biot supposes
sulphur to
contain hidro-
gen. .

While Mr. A. B. Berthollet was examining the nature of
tliis compound, Mr. Robiquet, apothecary to the hospital
of V^l-de-grace> was likewise making experiments on it,
at the suggestion of Mr. Vauquehn, to whom Mr. Berthol-
let's intentions were unknown. These led to similar con-«
elusions ; but were discontinued, as soon as Mr. Vauquelin
was acquainted with the labours of Mr. Berthollet. Mr.
Vauquelin had likewise given a tolerable quantity of the
liquid to Mr. Biot, that he might ascertain, if possible, from
its refractive power, the proportion of hidrogen it contains.
Wemay add, that Mr. Biot had already inferred the presence
of hidrogen in sulphur, during the course of his experiments
on refraction.

vn.

SMELTING OF CUPREOUS PYRITES. 5 J

VII

Account of the Metallurgic Treatment of Pi/riious Copper at
the JMiues of Clie.^sy and Sainbel, in t/ni Department of the
Rhone: ^// i)/r. Gueniveau*.

JL HIS paper contains several results of the analysis of th'e Products of th(>

nietallurcfic products of the works at Chess^^ which appear ^^'^^^^^^tniht

calculated to serve as bases for the theory ofsmeltin'o^ copper tlieoryof smel-

i)vrites, and particularly to show the effect of quartz added tmg copper py-

, . , . . rni f> 1 • • ntes, and the

to the ore HI tins operation. The fifth part is employed in eftectofquartzj

describing those chemical operations, that afforded new re-
sults ; and the remainder in deriving from those results the
most remarkable consequences, and pointing out their ap-
plication.

The chemical experiments were made in part at the la- in concert with
boratory of the School of Mining of Mont Blanc, under the ^^ Descotlls
inspection of Mr. Hassenfratz, and partly at the laboratory
of the Council of Mines, under Mr. Descotils.

The metallurgic products subjected to analysis were sco- They were the
rite from the pyritous copper, taken from the basin of the ^^^"^ a ^/!l^
fore hearth during the operation. Of these there are two matts.
sorts, one formed during the fusion of the roasted ore, the characters of
other during that of the roasted matts. The first sort is of a the 1st,
tolerably brilliant metallic gray colour ; exhibits laminae,
indicating a crystallization ; and may easily be confounded
with certain ores of oxidulous iron. The second has no me- o^ ^^^ 2d,
tallic lustre, is of a brown colour, and of a fibrous fracture.
The characters common to both are, they are tolerably com- common t«
pact, without any vitreous appearance, and almost without °^ *
blebs ; attractable by the magnet ; melt before the blow-
pipe without addition, sometimes emitting a slight smell of
sulphur, and with borax exhibiting the same characters as
iron ores; yielding iron when assayed in the dry way, and
sometimes traces of copper ; and forming a jelly with acids
with great facilit}'.

The following is a general description of the mode in General mode
which they were analysed. After they were powdered, they ° ^" ^^"^'

• Abridged from the Journal des Mines, Oct. 1806, Vol. xx, p. 245.

E 2 were

Si

Component
parts of the
scoria: No. 1

No. 2.

Assay gaVe
of iron.

The iron

slightly

oxiUed.

SMELTING OP CTJPREOUS PYRITES.

were treated witti concentrated muriatic acid, mixed with
a little nitric acid. With this tliey formed a tolerably te-
nacious jelly, which was diluted by adding water, and boil-
ing- it. The insoluble part, become very white,, was sepa-
rated, dried, weighed, and then heated red hot, to expel the
sulphur* The residuum had all the characters of wlex.
The muriatic solution contained no sulphuric acid. To
this ammonia was added in excess, which gave indications
of copper and dissolved the zinc. The precipitated oxide of
iron was treated while wet with a solution of caustic potash,
to separate the alumine. Into the aramoniacal liquor oxa-
late of ammonia was poured, to separate the lime : after
which an excesg of sulphuric acid was added, in order to pre-
cipitate the co})per by a slip of iron. By a large quantity
of ammonia the zinc was separated from the iron intro-
duced ; and the proportion of this metal was determined
by converting it into a prussiate.

The first precipitate of oxide of iron was examined anevr,
in the hope of finding in it portions of copper and of lime,
which might have escaped the first operations. The sul-
phur, copper, and zinc, were examined by separate experi-
ments.

From 100 parts of tlie scoriae of the roasted ore were ob-
tained silex 31, red oxide of iron 75, metallic zinc 2. Be-
side which there were some indications of copper and sul-
phur, and an atom of lime.

From 100 parts of the scoriae of the roasted matt were
obtained silex 22, red oxide of iron C)0, lime 3, sulphur 3 ;
beside a trace of copper and of zinc.
50 The assay in the dry way, with Guy ton's flux, gave 50
per cent of iron.

The iron in these scorife is very little oxided^ for the weight
of all the products of the analysis exceeds that of the sub-
stance employed, and ammonia precipitates the muriatic
solutions of a green colour*; It is observable too, that the
second kind of scorife contained much more iron than the first.

Some

iBtate of the 'The stats of the iron in this combination appears to me very doubt-

iron doubtful, fui . for, if we consider it as black oxide, that is with 27 per cent of
oxigen, it is not easy to explain the efFcrvesceuce, that the powdered

scoriir

SMELTING OF CUPREOUS PYRITES. 53

Sometime afterward Mr. Giieniveau examined a sped- Another spe-
men of scoriae of the first kind, obtained in like manner from anTr"edfo/*
the fusion of the ore, which was in the collection of the Coup- manganese
cil of Mines. His principal objects were to ascertain whe- ^ru^^^.^'g^^"
ther it contained manganese, and wliether the insoluble r€-
siduum had a mixture of sulphate of barytes : but as the
component parts of this specimen ditfered from those of the
former, he gives the following account of his analysis.

He treated 5 gram. [77g»*s.] of the scorire, thoroughly pul- Analysis,
verised, with ten of caustic potash, in a silver crucible. The
fusion was complete ; and on its being sufiTered to grow
cold, and a large quantity of water being added, no
green colour appeared, which evinced, that no manganese No manganese,
was present.

Another portion he treated with concentrated muriatic Examined for
a<4d mixed with a little nitric, to detect the alkalis. Having; ^^^^^^^*
separated the insoluble residuum, he treated the solution with
ammonia, which separated a part of the earths and metals.
The copper and zinc dissolved were then precipitated by
sulphuretted hidrogen; the excess of this gas >\as expelled
by ebullition; the lime was thrown down by oxalate of am-
njonigi ; and the liquor was evaporated to dryness. The am-
monlacal salts were then driven off by bringing the residuum
to a red heat in a platina crucible, and a pretty considerable
quantity of fixed salts remained. Having dissolved these in
a very small quantity of water, he added to the solution mu-
riate of platina, which occasioned no precipitate ; and en-
deavoured, but in vain, to obtain crystals by cautious eva-
poration and cooling; which convinced him, that neither Neither potash
potash nor soda was present. nor soda.

13y various trials he found, that the fixed residuum con- Barytes and
sisted of the muriates of barytes and magnesia. magnesia.

Lead too was an object of his particular research ; but he j^q je^^j
could not discover an atom.

scorlvB make with sulphuric acid a little concentrated, and with dilute
muriatic acid ; an effervescence owing to the decomposition of water,
since the gas has the smell of hidrogen set tree by iron. The same phe-
nomenon has been observed in scoriie from sparry iron ores, which were
not attractable by the magnet, and contained a great deal of manganese,
and but little iron.' " .

From

54 SMELTING OF CUPREOUS PYRITES.

From these data Mr. Gneniveau undertook a complete

analysis of tliis specimen of the scoriae of Chessy.

Its external Its external characters were the same as those of the scoriae

c\aracterb. No. 1. Its specific gravity was 3*61 . Assayed with borax

it gave 23 per cent of iron, without any signs of copper.

Analysis. Five grammes, well powdered, were treated with concen-

Treated with tr^ted muriatic acid, mixed with a little nitric. The whole

concentrated

muriatic acid, Coagulated mto a jelly. On this water was poured, it was

and a little ni- boiled, and fresh acid was added ; by which means a very-
white residuum was obtained. The decanted liquors were
mixed, and evaporated to dryness, in order to separate the
silex completely from the muriatic acid. Water being add-
ed, and filtered, a residuum was collected, which Contained
no sulphur, and weighed 1'75 ^^r. after having been exposed
to a red heat. This was fused with very pure caustic potash ;
and the whole of the compound being soluble in muriatic.
Residuum acid, Mr. GuenWeau inferred, that the residuum was very
pure silex. pure silex, without any mixture of sulphate of barytes.
Muriatic solu- ' The muriatic solution gave with sulphuric acid a precipi-
ed^Jiirsur*' tate of 0-90 gr. of sulphate of barytes, with which he ascer-
pburic acid, tained no sulphate of lime was mixed, and which was heated
red hot before it was weighed. The same solution was treat-
and hidrosul- ^^ with'hidrosulphuret of ammonia, which precipitated the
phuret of am- i , • r • • ■, • ^• i

monia. metals and alumme, leaving \n solution lime and magnesia.

The sulphurets were roasted, and afterv/ard dissolved by
pitro-muriatic acid : and lastly, the sulphur and sulphuret-
ted hidrogen were separated from the preceding liquor.
He had then two soUitions ; one. A, coiituining lime and
magnesia ; the other, B, containing the metals and alu-
miiie.
Lime thrown From tljie solution A the lime was thrown down by oxalate
down by ox2t- of aminoiiia; and the precipitate, being strongly calcined,
j^^j^ ° left 0*18 gr, of caustic lime. The magnesia, which re-

and magnesia rained, was precipitated by potash ; and, after being cal-
by ijotash. cined, weighed 0*1 gr.

Iron and alu- The solution B was treated by ammonia, an excess of
mine precipi- which dissolved the zinc and copper. The oxide of ir<m

tated by am- t i i • i • i ^ n t t i

mouia, and se- «-na the alumme, which tell down together, were separated

paratedbypot- by liquid caustic potash, assisted by heat. The red oxide

of iron after calcination weighed 2*30 gr. ; and the alumine,

after

SMELTING OF CUPREOUS PYRITES. 55

after exposure to a red licat, O.Ql gr. As the ammoniacal
solution of , copper and zinc had a very slight blue colour, it
did not appear necessary, to separate the few atoms of cop-
per: so the whole was precipitated together by carbonate of ^^PP®*" ^"'^
r • '^'^ • I r ^^ ^ . ^ Zinc by carbon-

potash, assisted by a boiling heat. The carbonate, being ate of potash,
calcined, gave O'l? gr. of zinc mixed with a very small
quantity of copper. The quantity of copper and zinc was
ascertained likewise by separating them from the iron by
sulphuretted hiilrogen, and it did not differ perceptibly from
this.

One hundred parts of these scoriae gave therefore silex 35, Component
barvtes, not sulphurated, 12, alumine 4, lime 3, magnesia 2, parts^ot" scoriae
red oxide of iron 46, oxide of zinc 3, beside some traces of
copper and of sulphur.

This specimen contained much less iron than No. 1, which Less iron than
was formed under the same circumstances: but the differ- No. 1.
ence will not appear surprising to those, who know how
much tlie proportions of the gangue, and foreign matter
added to the ore, vary in different smeltings. The follow-
ing are the most important consequences deducible from
these analyses.

1. The predominant parts of the scoriae of the pyrltous General infer-
copper of Chessy are oxide of iron and silex, the rest being ences.
variable, and in small proportion.

2. The combination of the silex with the oxide of iron is
effected in the furnaces in which the ore is smelted.

3. The presence of barytes, not sulphurated, announces,
tfiat the sulphate of barytes, which made part of the gangue,
is decomposed. No doubt it had been converted into a sul-
phuret, the sulphur of which was taken up by the iron or
copperj and the free barytes remained in the scoriae.

4. The scoria? arising from the smelting of the copper py-
rites and matts may be considered as iron ores, since they
yield a considerable quantity of iron when assayed.

The application of chemistry to the art of treating ores, chemistr}' the
observes Mr. (jueniveau, is considered by all metallurgists means of ex-
as one of the most certain means of elucidating its opera- f ^^icaf urol^ '
tions, and consetpiently improving its processes: and ac- cesses,
cordingly he relates in a few words the principal parts of
tlie metallurgic treatment of the pyritous copper of Chessy,

from

56 SMELTING OF CUPREOUS PYRITES.

f)om the account given by Messrs. Lemaire and Bouesnel,
iu order to render more perspicuous the comparison between
the chemical and metal lurojical results.

Treatment of The greater part of the ore wrouoht at Chessv is verv
t be ore of , ^ ^ , n

Ch<'s>y, which poor "» copper. It is a mixtuve of sulphuretted iron, sul-
is very poor, phuretted zinc, pyritous copper, and a small portion of
earthy substant es, as quartz and sulphate of barytes. The
Pounded, roasf- ore after pounding is roasted by a very economical process,
with thr^ddi- '^^^ch saves the greater part of the sulphur contained in it.
tioaof scoriu;. It is then smelted, with the addition of scoria? from pre-
ceding smeltings, and quartz broken to pieces, the propor-
tion of which varies from seven to ten hundredths of the
weight of the ore.

This smelting affords tvro products ; the scoriae, of wliich
Matts roasted analyses have been given, Nos. 1 and 3 ; and raatts, or sul-
rej.eatedly, phurets of iron and copper. These matts are roasted seve-
w'th scoriy; ^^^ times, and resm'elted with scoriae and quartz, but in less
and quartz. proportions than at first. By these operations are obtained
black copper, matts rich in copper, and the scoiite analvsed
No. 3." In all thiBse fusions no oxide of iron is reduced*.

The

* Most of the ores and products of the smehing have been subjected

to analysis, and assayed in the-dry way.' The following ai^e sOriic cH>ie

results. •

^ na.yMSoitne ^'j^g ^^ qj._ mailed at Chsssv meagre ore, is separated from \vh,d

poor ore. - o » i , ,

they cajl the yellow ore, ■which is much more rich, and is lOkstL'd and

smeltfc'd separfilely. Tjie poor alone is consid.rL'd here. The crude ore
roasted by itself, or in the great, most frequently yields ho copper 'ito
assaying. Once with four parts bf blaek flux Mr. Gueiiiveau obtain<Hi
from it 11 per cent of tolerably pure copper. By oheiuital ^laalysis it
never afforded him more than 4 or 5 per cent of copper j but it con-
tained from C6 to 55 of iron, accordinj!; as it was miked with the ganjjue,
pr piote or less toasted. The mean of the iron may be estimated at 40
per cent.
* *• The matts obtained fron) the first smelting of the ore amount to seven

hnndredihs of its weif^ht. They contairt about 25 parts of sulphur, 40
of metallic iron, and from i^5 to 27 v{ copper. It is of imj)ortance to
observe, that of 45 pirts of iron introduced into tlie furnace not abov;;
ij or 4 remain in the m^tt after the fiiSL fusion. The whole of the zipc
is volatilised in this oper.tion.
Black copper 'pi,^. |natts are roas'td and resmelted, and the products are blaek eop-
ai^ rich malts. • • , ^ r ,.■ . • v . . .^

per, coiUamuig 1 or 2 per cent oi metallic ironj and rich n^atts, con-
taining

SMELTING OF CUPREOUS PYRITES, 37

The mixture of quartz with the ore deserves particular ^^^ "^® °f
^ . . ^^ -11 11, quartz <es5ea-

notioe tor its importance. Many trials have been made to ^^i^

use other eartliy substances in its stead, but they were with-
out success ; and if a vein of quartz had not been discovered
in the neighbourhood, the working of this poor ore must
have been given up.

Of the component parts of the ore, the sulphur is sepa- '^^^ sulphur
'?ated in great part by roasting, and the zinc subHmes at the rXTing and
iirst smelting : but the iron, the proportion of which in the *^^ ^^^^ sub^
raetalHc state amounts to at least 40 per cent of the mass
to be fused, is unquestionably the most embarrassing for its trouble^oj^l
quantity, and because by being reduced it choaks up the
furnace, and stops the operation. The intention of adding
quartz is to carry the iron out of the furnace. In fact the ^[^ oxide corn-
analyses above given show, that a combination takes place siiex.
between the silex and oxide of iron; and that this homoge-
neous compound becomes sufficiently fluid in the heat of the
furnace, to allow the co[)per and the matts to separate from
the mere difference of specific gravity; so that itself can be
taken off the basin of the fore hearth during the fusion.

The afiflnity between the parts of this compound must be Tlieir afTimty
pretty strong, to preverit the reduction of the oxide of iron, ^ *' ^ ^ ^°^*'
rnd to enable it to yield its sulphur to the copper, which
does not happen but through some particular circumstance,
as in this case the presence of silex. It is an established Iron here
fact in metallurgy, that iron takes sulphur from copper : ^^''^^pJ'JJ. j^^.^^^^
here on the contrary the iron yields the sulphur to the cop- a double afli-
per, while itself unites with a compound in wliich it is al- "^^-'*
r.ady abundant to form the scoriae*, and does not appear in

the

taining ^.bout 21 part:^ sulphur, GG copper, and 8 metallic iron. It ap-
pears froDa various calcul;^tions, thai not above a hundredth of the iron
in the roasted ore reqiains i:i tliese two producf;, while they contain
iiearly half of the copper, that was in such small proportion.

The iron therefore jnis been separated and carded off in the scoriae, Iron carried ofF
-ince no other product retains any considerable quantity. ' »" the scoriae.

The sublimed matter, or cadmia of the furnaces, is nothing but oxide Zinc,
f'f/unc with some slight traces of copper, and free from iron-

• Beside tlie quartz and scoria; j;resunied to retain copper, scoriie frotn
th'j .;.njching of I lie ore, containing aboutO-66 of , oxide of ^oa only(analysis

^^o.

$8 SMELTING OF CUPRKOpS PYIITTES.

the rich matts, except in quantity sufficient as it were to

complete tlie saturation of tlie su1])hur.
A small q«an- The process adopted at Chessy is as remarkahle for the
extiacteTfrom "^^J^^^^ ^^ which it accomplishes its object, as for the sim-
a large portion plicity of the agents.it employs. From a ferruj^inous mass
of irou. containing only 4 or 5 per cent of copper, more than half

this is obtained; a result, that theory could scarcely have

predicted, since it can hardly render it conceivable. ♦

Oxide of iron fo ascertain how far oxide of iron is capable of direct

COIVi billed di- , • • ■ ^ ■^ ^r ^ • • •

rectiy with si- combmation with silex, Mr. Guemveau intntiately mixed

*^^* some red oxide with powdered quartz; put the mixture into

a crucible lined with a thin stratum of levigated quartz; and

exposed it to a forge fire equal to the heat of the furnace.

Forms a glass, The first trials produced only glasses njore or less opake

and coloured ; but at length he formed a compact com-

,pound of a metallic aspect, exhibiting laminae indicative of

crystallization, and in Cact perfectly similar to the scori<^.

The coating of the crucible was attacked, but the crucible

•was not melted. When the siiex was equal or superior in

unless the iron wj^jo^jt to the oxide, the product was vitreous ; when it was

naii\! ^"l^ ^ third, fourth, or sixth of the mass, it was compact and

metallic.
The operation He likewise attempted to produce in a crucible the same
smaU way!'^^ effects as took plaqe in tlie furnaces of Chessy. Accord-
ingly he mixed ;with great cave some of the rich copper py-
rites, as well roasted as possible, with 14 hundredths of its
weight of pure silex, .made it into a paste with olive oil, and
put it into a crucible not lined. On heating it as in a com-
mon assay, a portion of red copper and some grains were
obtained. Some matts were distinguishable, but the greater
part of the substance covering the copper had precisely the
appearance of the scoriae of Chessy.
Why does not Perhaps it may be asked why in iron furnaces, where an
silex unite with ^^,^ mixed with quartz is frequently smelted, the same com-

oxide of iron . * i ^^ i • • p i > t- i •

in iron fur- bmation between the silex and iron is not tormed? Jb or this
iiaces ? several causes may be assigned, acting either separately or

No. 1), are added to the roasted malts ; and the scorix issuing from the
furnace during this operation contain three fourths of their weight (ana-
lysis No. 2).

conjointly.

SMELTING OF CUPRF.OUS PYRITES. ^g

conjointly. In the first place no doubt the high temperature Owing to the
of these furnaces, and the long time the ore is kept in them, ^^f^^^ lengtrof
must be reckoned*; neither must we omit the presence of the operation,
earths and metallic oxides, the action of which on the silex ^^ ^j^ij^^ g^j,,
may counterbalance that of the oxide of iron. To confirm stances,
this opinion, Mr. Gueniveau took an artificial compound of
^ilex and iron, added ^ its weight of very pure white marble,
made the mixture into a paste with olive oil, and placed it
in a crucible lined with charcoal powder. A button of iron
and a few grains were obtained ; and the scoriae wore an
opake glass, of a light green colour, that did not contain a j. . .
fifth of the iron. An analysis of the scoriae of the high fur- mine,' and
nace shows, that the separation of the iron is much more "^^'ig^nese,
ix UT /• i-ii- promote tiie

complete, when lime, alumme, and oxidp ol manganese, are separation of

found in due proportion with the silex. ^^^^ ^^^^^•

The presence of other earths beside silex, which is advan- These earths,

tageous in iron furnaces, because they facilitate the reduc- f^ ^Q.^e^case"^

tion of this metal, is for the same reason prejudicial in prejudicial ia

furnaces for smelting cupreous pyrites. In these furnaces '' ^^ °^ ^'^^'

opposite eiferts are endeavoured to be produced on the iron :

the object being to reduce the oxide of the metal in the for-

juer ; while in the latter it is to prevent this reduction, and

at the same time to promote tlie reduction of the copper.

The means employed by the metallurgist to eff'ect these

opposite purpo:^es merit the attention of the man of science.

The scoriae produced in the smelting works of copper py- The scorix

rites resemble iron ores, not only in their aspect and mai^- i^("*«"yic'i "i

, f. -T ' -I 1-11 • 1 i" n-onthanmanr

netic properties, but m the laciiity witli which they yield a iron ores.

very considerable quantity of ii'on when assayed. It may
be reckoned, that the mean produce of the assay would be
at least 40 per cent ; a quantity superior to that of many
bog iron ores, which are notwithstanding wrought with ad-
vantage.

To ascertain how far these scoriae are capable of being Examined

wrouglit for iron in the high furnace, thev were treated with ^'^^^ '^ ^'^^^ *^
, c 1 CI- 1 " 1, • 1 , working them.

25 per cent ot carbonate ot lime, and a well united button

was obtained, equivalent to two thirds of the iron it con-
tained.

* This is an opiHioii long held by Mr. Hasscnfratz,

Mr

60 SMELTING 01? CUPREOUS PYRlTna.

May be smdt- ]\f r. Gueniveau thinks therefore, that they mav he smelted

like the boj^ iron ores with an ar£i::iUaceous carbonate or

. . ' . '■•

lime; and thon<:>h the iron produced might not be of prime

quahty, it would answer for several purposes. This must
appear an object of considerable importance to those, who
have seen the vast quantities of scoriae near the works. The
only operations required are pounding and smelting ; and
the smelting would not be very expensive, if coke could be
employed, as is done at Clu ssy for the copper, where the
whole process is conducted in a very intelligent and econo-^
niical manner.
Silex acts cher The observations nnd experiments here .given not only
inically m this j^^j ^^^ ^^ Consider silex, or quartz, as a metallurgic agent,
capable of separating iron in a state of combination from
copper, which it allows to melt alone or mixed with sulphur,
when assisted by the high temperature of the furnace ; but
"which eluci- serves to explain many passages in treatises on metallurgy.
^hiTs^thaf oc- '^^^^s^ works offer nothing precise respecting tlie manner, in
cur in metal- which substances mixed or combined in ores act on one ano-
iurgic -works, ^j^^^,^ ^^^ allow the separation of the metal, which we seek
to obtain. The same facts teach us why various kinds of
scoriae are mixed with the ores or matts under different cir-
cumstances: some being employed as fluxes of thej gangues;
others only to give fluidity to the whole mass, and produce
a kind of solution, which facilitates tlieir reciprocal action ;
and others act as a medium to separate the iron, when they
are not already- saturated with it. At Chessy the scoria? of
the ore perform this office in the smelting of. the matts, as
has been said. The general opinion' of metallurgists there-
fore, who consider the addition of earthy substances to ores
as serving merely to form fusible compounds WitH their
gangues, without paying any attention to the action they
exert on metallic oxides, requires modification in many
cases.

VIII.

TAliVE SIPHON. 6i

viih

Vcsctiption of the Valve Siphon of the tate Mr. kiki Argaki^j
liweutorcf the Lamps with a Double Current of Air*.

JL IILS improvement, though simple, is ingenious, and Description of
particularlr adapted to large siphons, that require to be re- * valve siphon*
moved IVom one vessel to another. A valve, as E, or H,
pi. II, fig. 1, is applied to the loot of the shorter or ascending
leg of a siphon A B, B C, at the other foot of which a step
cock F is placed. The cock being open, and the foot E
immersed in any liquid in a vessel I K, by moving the leg
E perpendicularly downvvard and upward, the liquid will
gradually ascend through the valve E, till it iTins out at th<r
point L. The pressure of the air on the surface I will then
be sufficient, to force the liquid through the valve E, as
long as this remains beneath it; and thus it will continue to
act as a common siphon, and the vessel will be emptied,
unless supplied from some reservoir, as N.

As soon as the siphon is filled, and begins to discharge Conveniently
tiie liquid at L i or at any period while it continues full ; if removable.
the cock F be turned so as to stop it, it may be very safely
and conveniently removed to any other vessel ; as the cock
will prevent the liquid from running out at one end, and the ^

valve at the other : and the moment the extremity E is im-
mersed in the liquid in another vessel, and the stop cock F
turned, it will act again as before.

The siphon may be filled in this way in a clear liquid, Mode of filling

and then removed into a vessel of the same kind of liquid, ^'^1^.°°^ 'J''^'

^ ' turbing the se-

that has a sediment at bottom, which would be disturbed by dinientof U-
moving itup and down. This however may not always be ^"^'^^^
convenient: Mr. Argand therefore makes an aperture with
a short perpendicular tube O in the horizontal branch B B,
through which, by means of a funnel, D, the siphon may be
filled, while the cock F is shut; so tliat it may be inserted
into the liquid, and made to act without disturbing it. When

* Sonniui'-j Blbrioihoque PJiysico-^'conomique, Nov. 18C6, p. 117.

th«

Igi GUNPOAVBETl PROVE R.

the siphon is thus filled, or when the fupnel D is not re-
quired, the aperture at O is closed by the stoyjple G.
Made to take For the convenience of carrying the f^iphon, as well as for
to pieces. packing it up, or cleaning- it, the horizontal and perpendicu-

lar branches are made to take asunder at the joints M M.
The nozzle L is likewise made to take off, as it is frequently
more convenient for the fluid to be drawn off perpendi-
cularly.

IX.

Description of a neic Instrument for proving the Strength of
Gunpowder, by Mr. Regnier, Keeper of the central Depot
of Artillery^,

Defects of the JL H'E old toothed wheel instrument for trying powder is
stiument!' obvioush defective, as the friction of the spring blunts and
rounds the edges of the teeth; the spring, being necessarily
strong, and always in a state of tension, loses in time its
strength and elasticity ; and the wheel, which is too much
confined in its movements, is exposed to irregular degrees of
friction, which likewise vary according as the instrument is
A weight here kept clean, or suliered to grow rusty. To obviate these de-
emp o)ec . fg^ts Mr. Regnier has recourse to a weight ; and the follow-
ing is a description of the mode in v;hich he applies it.
Decviption of A, plate II, fig. 2, is a stock of walnut wood, about 8
themsirument. inches long, with a plate of copper let into it, to support the
mechanism.

B, a small copper mortar, to hold the powder to be tried,
with a pan for firing it.

C, a brass wheel, grooved like the wheel of a pulley, with
thirty ratchet teeth on its circumference. To this wheel is
fixed a projecting piece, or obturator, accurately covering the
mouth of the small mortar, B.

D, a forked support, in which the wheel C plays freely on
its axis.

E, a spring pallet, acting as a click, to stop the wheel at
the point to which the strength of the powder carries it.

♦ Sonniai's Bibliolhique, March, 1807, p, 415,

MODE OF MAKING PHOSPHORIC ETIIEtt, ^3

F, a small copper weight suspended by a string, which 19
fiistened by a knot at the hole G in the thickness of the
wheel. The string passes through an aperture in the
wooden stock and the plate of copper, sufficiently large to
occasion no friction.

li, a loop at the end of the handle, to hang up the instru-
ment when not in use.

To use it the small mortar B is fdled with powder, and the Method of
end of the linger passed over its mouth, that no grains may "^"^g*^-
remain between the mortar and its obturator. A little priming
is to be put into the pan, and the instrument is to be held
in a horizontal position in the left hand, while it is hred. A
red hot iron skewer is the most convenient for setting fire to
the priming.

The clastic fluids extricated on firiYig the gunpowder im- Its mode of aq.
pel the obturator upward, thus turning round the wheel, and ^io"*
raising the weighty that resists its action. The strength of
tliis action is indicated by the extremity of the pallet E, that
marks the degree to which the weight is raised.

The degree marked good denotes a good powder for shoot-
ing; but the farther it goes beyond this, the better the
powder.

The same powder will not always produce an equal ef- A.dapted to the
feet on the same instrument; to prove it properly therefore P^n^^^'^^s of the
several trials should be made, and the mean of them' taken. oiX^"^^"^
To prove the large grained powder usedfor military purposes
other modes must be adopted, this instrument being suited
only to the sportsman.

Mof^e of maldng Phosphoric Ether by means of a peculiar
Apparatus; hy Mr. P. F. G. Boullay, Apothecary, at
Paris, Read before the First Class of the Institute, March
the '23dy I8O7*.

J30Tri Scheele and Lavoisier had attempted to trans- unsuccessful
form alcohol into ether by means of the phosphoric acid, attempts to

make phos-
♦ Annales de Chimie, vol. Ixii, p. 192, May, 1807. ' phoric ether,

without

g4 >fODE Ot MAKING PIIOSPHOIlIC ETHER;

without success, when Eoudet the younger published a pa-
per on this subject in the XLth vol. of the Annales de Chi-
mie. The phenomena he described announce a real action
' between the acid and alcohol, and display various circum-

stances, that usually accompany the formation of ether.-
However this chemist confessedj that the product he ob-
tained possessed little volatility ; that it was (Entirely soluble
in water ; and that, thdtigh it liad a peculiar smelly it did
not exhibit the characters of real ether*

r%. -r.r\r. ♦>.« Convinced by various trials^ that the want 6f action of the
Owing to the *' ^

difficulty of phosphoric acid, when concentrated or even glacial, on alco-

acid^& alcobol ^^'^^ depended particularly on the difficulty of uniting these

into intimate two substances, and multiplying and prolonging the contact

eoiitact. ^^ their mutual particles, I resumed, the attempt; and the

hope I conceived of obtaining a more satisfactory result ^\as

realized by the following process.

Apparatus for '^^ ^ tubulated retort, placed on a sand bathj I fitted a

thii purpose, receiver, likewise tubulated, which comtnunicated by a

Welter's tube with a bottle full of limewater. From this

bottle a second tube proceeded to a pneumatic trough, and

there opened under an inverted jar.

Into the retort I introduced 500 gram. []603 grs. troy] of
pure phosphoric acid, arising from the combustion of phos«
phoros by nitric acid, vitriGed, redissolved, and evaporated
to the Consistence of honej*

On the tubulure of the retort I placed a glass vessel, thaf
may be called a reservoir^ of an oblong shape, and open at
both extremities, each of which might be shut close by
means of a cork. From the lower end a tube descended to
the bottom of the retort, being thus immersed in the pho's-
phoric acid. The upper end, in which was a funnel, that
might be made to communicate with the reservoir, or not, at
pleasure, had a small aperture with a grotmd glass stopple
intended to give tent to the air, when displaced by pouring
in a liquid. See plate II, fig. 3 ; and for its horizontal sec-»
tion hg. 4.

The apparatus being thus disposed and carefully luted,
a,nd the tirst receiver being cooled by a mixture of pounded
ice and common salt, a tiie was kindled under the retort,
and the heat gradually increased, so as to heat the acid to

MODE OF MAKING PHOSPHORIC ETHER. 6*5

95^ of Reaumur [v>4G° F.]. An equal weight of alcohol at
40^ was then introduced into the reservoir, and by means of
the lower cocic allowed to fall drop by drop into the hot and
fluid phosphoric acid, The^ mixture took place with vio-
lence and ebullition ; it assumed a black colour, and copious
streaks immediately appeared on the upper part and neck
of the retort.

The fire being kept up, and the distillation continued to Products^
dryness, there passed into the receiver,

1, A hundred and twenty gram. [3oz, 6dr. 53gT.] of alco- Alcohol

hoi weakly etherised. ^^'s!^^'>' ^'^'^"

2, Two hundred and sixty gram. [8oz. 2dr. 55gr.] of a ^ ^^^^^ ether*
white, light fluid, of a brisk smell, and much more ethereal eal fluid.
than the former.

3, Sixty gram. [loz. 7<ii*. 26gr.] of water saturated with Water satu-

ether, on which swam about 4 gram. r62u;rs.l of a. lemon- '^^'^'^ ^^'^^

1 I ,1 • 1 -.1 .-11 • ■■, ciher, and oil

coloured tiuid, with an empyreumatic smell, very sunilar to of wine.

that which comes after sulphuric ether, and which is com-
monly known by the name of sweet oil of wine.

4, Another fluid of an insupportably fetid smell, redden- a fetid liquor
ing tincture of litmus, and combining with carbonate of with acetate of
potash with effervescence. This combination, being evapo-
rated to dryness, was a deliquescent salt, foliated, and per-
fectly similar to acetate of potash.

The hmewater was rendered turbid, but not till toward the A little car-
end of the distillation. ^^^^'^ acid at

Beside the air in the vessels, a gas was collected of a sweet ^ , . ' ,
11 1 • • . 1 ■ r, 1 Ether in tho

and penetrating smell, burnmg with a white flame, and state of gas.

when burned depositing on the sides of the vessel a very

plentiful coat of carbonaceous matter. It was a little ether

that escaped condensation, that passed at the same time as

the most ethereal liquid product, and a little before the

white vapours, that announced the presence of the oil.

What remained in the retort was a blackish, glassy mat- j^^^. .
ter, consisting of phosphoric acid, and a little charcoal.

The first two products mixed together, and rectified over Rectified,
dried muriate of lime, at a heat of about 50° [144°], aflbrded
near Co gram. [loz. 7dr. 27gr.] of a liquid, which in smell
and taste had the greatest resemblance to the purest sulphu- Pure ether.
ric ether, It marked like it 60^ on Bauuie's areometer, the
:. Vol. XVIII— Sept. 1807. F thermo-

66

BARTTIC SALTS DECOMPOSED BT SODA.

Alcohol slight-
ly etherised.

More ether.

Phosphoric
ciher

most resem-
bling sulphu-

therraometer bein^ at 10<^ [54|°]; dissolved in eip^ht or ten
parts of cold water; evaporated quickly; boiled at 30^
[99 P] ; dissolved resins and phosphorus; burned v/jth a
whitish flame, leaving a carbonaceous residuum, and with-
out any trace of acid appearing from its combustion on the
suface of water.

The other product of the rectification was alcohol, slightly
etherised, This alcohol, passed again in the same manner
through the phosphoric acid employed in the experiment,
gave rise to the formation of a fresh quantity of ether in
every respect resembling the first.

From these facts, and on exarhination of the products
submitted to the inspection of the class, it appears to me,

1st, That phosphoric acid is capable of transforming al-
cohol into a perfect ether, by means of the apparatus I em-
ployed, and the precautions 1 have mentioned :

2dly, That, of all the different ethers known, the ether
resulting from the action of phosphoric acid on alcohol has
the greatest analogy to sulphuric ether, with respect to its
properties, and the phenomena observed in preparing it.

XI.

Acetate of
soda said to be
decomposed
by baryies.

Solution of ba-
rytcs added to
acetate of soda,
cryitals fall
down.

Remarks on the Decomposition of Acetate of Barytes hj Means
of Soda; hy Mr. D'Arcet*.

JLn N°. 180 of the Annales deChimie, p. 286, Mr. Perpe-
res, speaking of the formation of acetous acid in cases of
indigestion, says, that, to ascertain the presence of this acid,
h? saturated it with pure soda ; afterward decomposed the
acetate of soda by means of barytes ; and having thus set
the soda free, dissolved it in alcohol, which, uniting with
the water of the solution, precipitated the acetate of barytes,
that had been formed. The result of this experiment ii
certainly inaccurate, as the following details will show.

Take a hot saturated solution of barytes, pour it into
acetate of soda, and immediately an infinite number of ht-
tie, shining, and iridescent laminae will fall down. If these

« Annales de Chimie, Vol. LXI, p. 2-18, March 1807.

he

BARYXrC SALTS DECOMPOSED BY SODA. 6^

"be separated from the liquid after it is completely cooled,
Washed in the smallest possible quantity of water, and dried
quickly by pressing them between several folds of blotting
paper, they will be found to be crystals of pure barj'^tes, These pure
without any mixture of acetate. Of this I satisfied myself ^'y^^^-
in the following^ way,

1. 1 exposed part of these crystals to the air. After some Converted into
days I washed the carbonate thus obtained with pure water, exposure to
which then took up nothing, that sulphuric acid, or alkaline Hie air.
carbonates or sulphates would throw down. The whole

of the crystals therefore had been converted into carbonate;
which would not have been the case, had they contained any
acetate of barytes.

2. I dissolved two or three grammes of the same crystals Were alkaline.
in distilled water. The solution restored the blue colour of
reddened litmus paper : consequently it contained an ex-
cess of alkali.

I added a few drops of sulphuric acid to this solution, J^lpli^nc acid
J .. r»ii/»i f IT lormed With

and a precipitate ot sulphate ot barytes was tormed. 1 them sulphate

tested the liquid again with litmus paper, and I still found of barytes,
an excess of alkali. I then gradually added more sulphuric
acid, till there was a slight excess of acid in the liquor;
filtered it, and found it no longer contained any barytes, but
a little free sulphuric acid. This would not have been the
case, had^ the crystals contained any acetate of barytes ; for,
on this supposition, the moment when the excess of acid
began to be sensible by the test paper, only a small portion and no acetous
of the acetate would have been decomposed, and acetous ^^^ appeare .
acid would have been set free. The filtered liquor there-
fore ought to have contained a slight excess of acetous acid,
and the undecomposed acetate of barytes : but this was con-
tradicted by the experiment.

3. The mother water of the crystals employed in the pre- The mother

ceding experiments ought to contain only that small quan- ^f^^\ contain-
j^'j. o J 1 • 1 • 1 1 • • 1 . , edonly pure

tity or pure barytes, which it could retain m solution when barytes and

cold, in addition to the whole of the acetate of soda em- acetate of soda.
ployed. This too the analysis of the mother water demon-
strates, if alcohol be poured into it, as Mr. Perpj^res directs.
The shining scales that fall down are nothing but crystals
of barytes: and examined in the way I have mentioned

r 2 above.

jB$ B\RTTtC SALTS DEfOMPOSED BY SODA,

al>ove, they produced nothing but veiy pure carbonate of
barj-tes, aud not an atom of acetate. If the mother water
be farther examined with sulphuric acid, or alkaline carbo-
nates, it will immediately appear, tliat it contains but little
barytes and a great deal of acetous acid ; which becomes
still more sensible, if it be evaporated to dryness, and the
residuum be redissolved in distilled water : for this solution
does not contain an atom of barytes, but merely acetate of
soda, the little barjtes that was present being reduced to the
state of a carbonate during the evaporation.
Barytes does Hence it follows, that barytes does not decompose acetate
acetate of soda. ^^^'^^^ J ^^^ ^^ ^^^^ contrar}^, that, if we try the opposite
experiment, it will succeed. In fact the whole of the ace-
tate of barj^tes may be decomposed, by adding to it a suffi-
cient quantity of pure soda to saturate all the acetous acid.
The barytes contained in the phial accompanying my letter
was prepared in this way.

My object is not to invalidate the conclusion of Mr. Per-
peres, which appears to me just, and consistent with what
was already known. I only criticise one of the proofs he
Potash and l^as adduced, and avail myself of this opportunity, to remind
soda have ^jj^ public, that in the year 12 a paper on the affinities of
stronger affim- i -m/r . o i m. . i • i .

ties than ba- barytes, by Mr. Antrye and rayseli, was inserted m the An-

rytes for all nales de Chimie ; where we proved, that in the classification
cept the sul- ^^ alkalis barytes ought to be placed before potash and soda
ph uric and only with respect to the sulphuric and carbonic acids, the
affinities of potash and soda being superior in every other
case. How is it, that, notwithstanding the facts so posi-
tively announced in that paper, different authors have re-
tained the ancient order of affinity assigned to barytes ? It
appears to me, that, with regard to experiments, either the
results of such as are made public should he adopted ; or
they should be refuted, by repeating them, and proving their
erroneousness.

I shall conclude this note by citing in confirmation one of

the processes, the goodness of which has been proved by our

labours on barytes in the large way. It follows naturally

from the facts mentioned above.

This theory The decomposition of muriate, nitrate, and acetate of

applied to the barytes by potash or soda is so complete and easy, that it

BARYTIC SALTS DECOMPOSED BY SODA. ^g

is unquestionably the mos.t simple method of procunng in » tammg pwre

, . , - - , 1 ri ^t • barytej in the

laboratory the biirytes that may be wanted, tor this pur- large way vith

pose ahaiidred parts of sulphate of barytes accurately mixed successu
with twenty parts of charcoal powder are to be calcined by
a strong heat in close vessels. After being exposed to a
high heat for an hour, the crucible is to be suffered to cool ;
the residuum separated and diluted in water; and a suffi-
cient quantity of nitric, muriatic, or acetous acid added,
llie mixture is to be heated gently, when it will give out a
large quantity of sulphuretted hidrogen and carbonic acid,
which must be guarded against with care. When the effer-
vescence ceases, and test paper indicates a slight excess of
acid in the liquor, it is to be filtered and evaporated, to de-
compose the sulphuretted hidrogen, and precipitate the sul-
phur, that was retained in solution*. The residuum is to
be redissolved in the least water possible, and a saturated
solutionof caustic potash is to be added. At the instant of
mixture a large quantity of crystals of barytes falls down.
Tlie whole being left at rest in as low a temperature as pos-
sible for an liour or two, the mother water is to be poured
off; the crystals are to be washed with a little distilled water,
and then dried by pressing them between folds of blotting
paper ; and lastly they are to be dissolved in as much boil-
ing water as is necessary. This solution, being filtered, will
let fall when cold the barytes, which is much more pure, and
costs less, than when obtained from the decomposition of
nitrate of barytes by heat alone.

It is to be observed, that the muriatic or acetous acid is Muriatic or

^referable to the nitric, because each forms a more soluble f^^'^"^ ^'^^^} *•
^ ... be ijreterred.

salt than the nitric, and the washing is more easy ; and be-
cause in making the solution the nitric acid is partly decom-
posed, and oxigenizes a portion of the sulphuret of barytes,
so that soniQ^of the acid is lost, and some of* the barytes ub-
feorbed by the sulphuric acid formed.

The caustic potash used in this process must be prepared The potash
from carbonate perfectly free from sulphate. ^'^ ^^/^Z^

* The same object may be attained more readily by pouring into the
liquor a few drops of solution of nitrate of copper or lead, letting the me-
taliVo sulphuret subside, filtering afresh, &g.

Observathn

70 SCIENTIFIC NEWS.

Ohservation on the preceding article hy one of the miihors of
the Annales de C hemic.

The result ex- Agreeably to the request of Mr. d'Arcet, in addressing to
Guvton ^^ "^^ ^^'® "°*^' ^ ^^^^ examined the liquid in the phial ac-
companying it. It was more than half full of small, white,
crystalline scales. Tlie liquor acted powerfully on paper
tinged by mallow flowers, changing it green. On dropping
into it sulphuric acid a little in excess, a copious precipitate
of sulphate of barytes was formed, without the least smell
of acetic acid. After having filtered the liquor from this
precipitate, I evaporated it by a gentle heat, in a platina
capsule ; but it left no trace of any neutral salt. No doubt
can remain therefore, but the acetate of barytes is radically
decomposed by soda.

L. B. GUYTON,

SCIENTIFIC NEWS.

Adjudication of Prizes, with a proposed new Question, hy the
Imperial Academy of Sciences at St. Petersburgh,

Question pro- A HE Imperial Academy of Sciences had proposed in

posed by the their last public notice the prize of five hundred rubles
academy on,^ _. i,.,

light. [A II 2 J 05. J, to be given to any professor or natural philo-

sophy, who would establish, and communicate to the aca-
demy, a series of " new and instructive experiments on light
** considered as matter ; also, on the properties, which may
** in part be attributed to it; on the affinities, which it may
*' appear to have either on organized or unorganized bodies;
** and upon the modifications and phenomena of these sub-
*' stances by their combinations with the matter of light.'*
— The academy had declared at tlje same time, in order not
to confine the learned who might have been pursuing simi-
lar inquiries, that they contented themselves with stating
the subject generally, leaving them at liberty to consider
the question in any point of view, that might appear best
calculated to elucidate a question so diflicult.

The academy has received within the prescribed time six
tracts on the question, each having a note sealed and motto.

— viz.

SCIENTIFIC NEWS.

— viz. No. 1. In the Russian language with the motto: ** A
" philosopher who has learned to doubts hioivs more than all
*' tJie Itarncd, ^c/' No. 2. In the Russian language :
" Time is the earliest thing in nature, ^-c." No. 3. In La-
tin : " Est-ne color proprius verum, lucisne repulsus eludunt
** aciemf* No. 4. In French: " IXox abiit, nee tamen orta
** diesT^ No. 5. In German: " Ut noscas splendore novo
•* res semper egere, et primum factum, Sfc.'' No. 6. In
Geniian : " La physique ne sera tcritablement i^ne science,
** que lorsque tons les effets naturels se dcdidront clairement
** dhin seul et meme principe evidemment dtmcntri'.'"

The first tliree tracts, beside the common fault of wantin<^
new experiments, a complete and instructive series of which
was required by tlie academical notice, contained hypothe-
ses and propositions, either well known, erroneous, or ill
expressed, and advanced without demonstration. F or these
reasons the academy did not' think they hud any claim to the
prize.

The tract No. 4 is not without merit. The author enters
upon several interesting questions concerning the nature of
light, in a: manner that readily convinces us he is no stran-
ger to the subject. But the dehciency of connexion and
systematic arrangement, which is perceived in it, and above
all, the absolute want of new experiments which might lead
to new results, or serve as a support to a number of hypo-
theses advanced by the author, and destitute of every spe-
cies of demonstration, would not permit the academy to
adjudge the prize to this memoir, even had there been none
of greater merit.

As to the last pieces. No. 5 and No. 6, the academy has
found them worthy of tlieir particular attention, from the
report of the committee appointed to decide on the different
performances. These essays are agreeable to the principal
condition stated in the notice, inasmuch as chey contain a
great number of new experiments on the effects and proper-
ties of hght, and a judicious application of those, which,
though already known, were repeated, whenever they ap»
peared doubtful to the authors. Both pieces are executed
upon a plan wisely conceived, expressed with clearness, and
arranged in sufficiently systematic order. Ou the other

hand,

71

72 SCIENTIFIC NEWS.

hand, in each were found some incoherent and contradlrtory
conclusions ; as also propositions advanced without sufficient
proof; beside some errours, and obscure passages. But as
these imperfections were overbalanced by researches of great
merit, the academy, without accedinjj to every assertion of
the authors, have nevertheless thoun:ht it their duty, to di-
vide the prize between them, thinking them worthy of en-
couragement and honourable reward.

On opening the two sealed notes. Doctor Henry Frede-
rick Link, professor of natural philosophy at the university
of Rostock, was found to be the author of No. 5 ; and Mr.
Placidus Heinrich, professor of natural philosophy and ma-
thematics at the Abbey of St. Emereau, at Ratisbon, the
author of No. 6. The notes of the remaining tracts were
burned, without being opened.

Question on When the academy had made public the notice, in which

the resistance , , i i • i

of fluids. ^he marine department proposed a prize on the question

concerning the resistance of fluids, they had engaged to
publish also the judgment, which that department, in con-
junction with the academy, should make on the memoirs
presented. Coniformably to this engagement, the academy
announce the receipt of three menioirs :— viz. No. 1. with
the motto: " 5if modus hsso maris ct viarum miiitiaeqtte.**
No. 2. ** Praesta vatura voce doceri, quam mgenio svo sa~
"^ pere. No. 3. " England and France agree,' ^ The last of
these arrived after the term.

Neither of them was found to satisfy all the conditions of
the problem : but, as the tract No. 2 exhibits a new theory;
which, though not established upon grouiids sufiiciently so-
lid, or applied to naval architecture in the manner the no-
tice required, is preferable, in some measure, to the theories
of Rome and don George Juan, agreeg-better with experi-
ments than the common theory, and deserves therefore to
be noticed advantageously ; the marine department, to re-
compense the author for his trouble and laudable efforts,
have decreed to him the prize of 1 00 Dutch ducats [£46 5s,],
and the academy have given their sanction to the decision.
The opening of the sealed note discovered the author to be
Mr. Zacbary Nordmark, professor of niathematics in the
university of Upsal.

In

SCIENTIFIC NEWS. 7^

In pull Vi sib Ing- these jn<lo^ments and cllstribution of prizes

for the year 1806, tlie academy proposes the following ques-

ti6n for the present year 1807'

Chemistry teaches us the means of discoverinsr the noxious Questioafcrf
. . . . . . Ib07.

<|uahty of mineral bodies, whereas it is only empirically,

that we have learned to distinguish poisonous plants from
those that are not so. Even the characteristics, by which
we think ourselves enabled to determine on the presence or
absence of poison in vegetables, are not always sufficiently
certain and incontestible. The livid colour, for example,
which has rendered many ])lants suspected, is a fallacious
sign. The burdock (arctium lappa) looks dull, and is of a
pale colour, yet it is a wholesome plant; on the contrary,
the laurel (daphne) is remarkable for the beauty of its
flowers and leaves, yet this is poisonous. The families of
ranunculus and anemone are as beautiful as they are nume-
rous; they are however for the greater part noxious. The
same may be said of the disagreeable smell of plants, which
is taken for a diagnostic of the poisonous quality, and which
sign is equally uncertain with the preceding. The smell of
the laurel is very agreeable, while the stinking orach (che-
nopodinm vulvaria), an innocent and even salutary plant, is
of a very disagreeable smell. The smell of coriander is dis-
agreeable to many persons, yet it is of a very salutary na-
ture. The umbelliferous plants, that grow in wet and marshy
situations, have the reputation of being poisonous ; notwith-
standing this, the water parsnep, (sivmj and all its species,
the sison iimndatum ct suhtim, the phellandrium aquaficum^
the angelica si/Ivestrts, the KEgopodium podagrariay plants
which thrive in marshes, contain no poison. It is plain,
therefore, that neither the livid colour, disagreeable smell,
nor growth in niarshy places, can furnish us with certain
and indisputable signs of the presence of poison in plants.

The pretended repugnance of animals to pernicious plant*
is evidently as little "infallible. The division of plants,
madt/ by botanists, into classes, orders, and families, ac-
cording to tlieir nature, is not more effectual in discriminat-
ing those that are venomous. To be convinced of this we
have only to observe, that among the species of the night-
shade, a genus so much suspected, are found the potato

(jolanum

74 SCIENTIFIO NEWS.

fsohtvum fuherosnmj, and i\\e winter cherry fs. pseudocap-
sicumji which possesses the virtues of a stimulant, and of
destroying the pernicious principle in narcotic plants.

In consequence of this want of an exterior and natural
certain sign, by which poisonouS plants might be immedi-
ately detected, it would be desirable, to tind out some easy
method of examining them, such foi- instance as a kind of
eudiometer, or any thing that might produce changes in
them, which, like the black colour assumed by mushroom*
when they are boiling, might indicate their noxio^us quali-
ties ; though it must be confessed, the criterion of poisonous
mushrooms is not yet sulficiently established,

" An easy method is therefore required, by which any indi"
vidua/, not having the least knowledge of botany, may deled
poisonous plants; in a short time, at a small expense, and in a
manner perfectly decisive.'^

The prize is one hundred Dutch ducats [^£46 58.1 and
the precise time, after which no memoir can be admitted to
the competition, is the 1st of July, 1808.

The academy invites the learned of all nations, without
excluding its honorary members and correspondents, to in-
vestigate this subject.

The learned who compete for the prize are not to put their
names to their works, but merely a sentence, or motto ; and
send with them sealed notes, which must have the same
motto on the outside, and the author's name, quality, and
place of residence, witliin. The note of the piece to which
the pnze is adjudged will be opened, and the rest shall be
burned unopened.

The tracts should be written in legible characters, either
in Russian, French, English, German, or Latin, and must
be addressed to the permanent secretary of the academy,
who will deliver to the person appointed by tiie author a re-
. .>ceipt, marked with the same motto and number as sliall be
inscribed on the piece. The successful memoir is to be the
property of the academy, without whose formal permission
the author shall not print it.

The rest of the tracts may be received back from the
secretary, who will deliver them at St. Petersburgh to any
person commissioned by the author to apply for them.

Discovery

SCIENTIFIC NE\yS. 75

Discovery of a new Planet, hy Mr. Olbers.

Mr. OLBERS has written to Mr. le Fran9ais Lalande, New planat
that he has recently discovered a new planet. The follow- oibers!"^^ ^
int^ are such elements of its orbit, as he has been able to
determine.

The 2yth of March, at 21 minutes after 8 mean time, its Elements of
ascension was 134° 8'; its north declination 11° 4?^ its orbit.

On the 30th, at 12h. 33^, mean time, its ascension wiis
183° 52'; its north declination 1 1° 54'.

It has been seen at Paris, and was visible to the naked Seen at Parla
eye. Its size appears nearly that of a star of the fifth mag- ^y t^* naked
nitude. Apparently it is about the same distance as the
three lately discovered planets, Ceres, Pallas, and Juno.

Fluoric Acid in Teeth and Bones.

In our Journal, VoL XIII, p. 214, is a letter with which Fluoijc acidtn
we were favoured by Mr. Brande, to show, that the enamel ^^®^ ^ bone«*
of the teeth does not contain any fluoric acid, an ItaUan
chemist having asserted, that they did. A letter from Mr.
Gehlen to the editor of the Journal de Physique, dated
March l6, informs us, however, that the fluoric acid exists
both in the enamel and bony part of teeth, and in other
bones. His words are :

*' The very extensive and accurate experiments of Mr,
Berzelius of Stockholm have proved, that the enamel and
the bony part of the teeth of man and of the ox, as well as
their bones themselves, contain fluoric acid. The foUowino'
are the results of the analyses.

" Enamel of human teeth, Enainel of the teeth of the ox.

Phosphate of lime 85*3 81 Component -

riuate of lime 3*2 4 P^''^^ ®f t^«

Carbonate of lime 8*0 7'1 tee\h

Phosphate of magnesia 1 -5 3

iSoda, combustible animal mat- Natron 1 '34

tcr, water 2 Animal matter 3.56

lUU 100

Osseous

76

SCIENTIFIC NEWS.

•« Osseous pnrt4!fhmon teeth. O*seou^ parUfiht teeth of

•r.tfceubonj P^iosphate of lime .'• 61-9.5 57.46

tBiit» Fluate of liiixe 2*10 5-6(>

Cai!)onate of lime 5*50 1 -SS

Phosphate of magnesia • • . • 1 '05 • . • 2*07

Soda, with a little mnriate of

soda 1*40 2-40

Gelatine, veins, water 28*00 31 *00

100 ]00

** Dry fresh hvmnrt homes, Drrj^frerh ox bones,

of b«mes. Gelatine 32-17)

Veins belonging to their or- > 33*30

ganization •• 1*13)

Phosphate of lime 51-04 •• 55*45

Fluate of lime 2*00 ••• 2*90

Carbonate of lime II -30 3*85

Phosphate of magnesia ••.• I-16 2*05

Soda, with a small quantity of

muriate 1*20 2*45

100 100 "

We regret, that we have not the particulars of the ana-
lyses before us, that we might see the proofs of the fact, or
be enabled to^trace the causes of the fallacy.
Fltioric acid in Mr. Berzelius says too, in a letter to Mr. Vauquelin^ that
unne. ^^^^ precipitate obtained from urine by limewater, when

washed and dried, being treated with sulphuric acid, gives
out fluoric acid, which corrodes glass. But it requires a
pretty considerable quantity of this precipitate, to give any
very perceptible signs of it.
Mtiriatic acid He adds, that the Swedish chemists have never been able
.nnd srida ob- |q obtain muriatic acid and^ soda by means of the galvanic
^"inTsin onfy pi^^ f'^m water perfectly pure. That they find pure water
T.heii ^aii is ^ very bad conductor; but if the least particle of salt be
present, the decomposinon is moit lapid, and its acid and
alkali are set free.

Sulphur

SCIE?<TIFIC NEWS. 7/

Sulpliur injlamed hy oxide of lead.

"Dr. THOMSON'S paper on th^ oxides of lead, Jounml, Brown oxide
\ o\. VIII, p, 280, having been translated into French, and ^ulp}iur\ri^^
userted in the Annales de Chimie, the passage in which he turaiion v/itk
ays he did not succeed, in triturating sulphur with the ^^
rown oxide, p. 283, is thus commented upon.
** Nothing however is more certain, than that Mr. Vau-
quehn has inflamed sulphur by triturating it with brown ox-
ide of lead, as he formerly mentioned. He lately repeated
•this experiment, in one of his lectures, before upwards of
fifty persons, among whom was prof. Proust of Madrid.
The only precautious the experiment requires are, to boii j^t^j.^^;,^ ™g^
the nitric acid a long time on the brown oxide, that no mi- cd-ntiuntu
Ilium may remain among it; to wash it afterward with a,
great deal of boiling water, so as to take up all t.lie nitrate
of lead; and lastly, to dry it well, aud to triturate it widi
flowers of sulphur equally well dried.

" On observing these essential conditions, there can be no
doubt, but Y)r. Thomson Avill succeed in inflaming the sul-
phur. The supposition he makes, to account for the plie-
nomeuon, is inadmissible, for Mr. Vauquelin never employ-
ed oxigenized muriatic acid, to prepare the brown oxide of
lead.

Yttria and Cerium.

THE chemists at Upsal at first imagined, that cerium yttnaoxJ**-
was nothing but u mixture of barytes, yttria, and magnesia, nizes nimuni*
Mr. Eckeberg, desirous of comj^aring them, has found that
yttria, after having been a long time exposed to the action
of fire, gives out oxigenized muriatic acid, when dissolved in
the common muriatic acid. Is yttria, asks Mr. Berzelins,
one of the new metals, uranium, titanium, or cerium, with
its nature ai it were changed ?

Mr. Gahn has formed an alloy of cerium with iron, partly AHoy of ce-
in a grayish powder. '^"™ ^^'^ ^«°-

New

78

SCIENTIFIC NEWS.

New Process proposed hy Mr. khi.kiKV.^ Administrator Ge-
neral of Forests, for scowering Wool.

Wool cleansed THIS process consists in repeatedly immersing the wool
^ "^ * *• in a warm chalk bath. The calcareous earth forms an ani-

mal soap with the greasy matter of the wool. By this me-
thod the wool is cleansed quickly, and without affecting it»
quality.

Argand's
lamps, with
bUie glass
chimneys.

The light
enclosed in
alabaster or
Derbyshire
spar.

Ar guild's Lamps.

MR. ARGAND has made different improvements in hi*
lamps. The first consists in using blue glass chimneysF,
which render the light mild, like that of day : for the light
traversing a medium similar to that of the atmospheric air, is
modified in a similar manner. This is an important advan-
tage to many artists, who find it necessary to work by arti-
ficial light, as it is well known, that several colours do not
appear by it of their natural tints *.

Another mean of obtaining a very mild, pleasant, and as
it were mysterious light, is to enclose the beak of the lamp
in a vase of alabaster or Derbyshire spar, the bottom and
neck of which are pierced, to admit this beak, while the body
of the lamp, that contains the oil, is concealed behind it.
A room lighted in this manner has a very curious and agree-
able appearance f.
Means of pre- Mr. Argand has likewise found the means of remedying
from overflow- ^^ inconvenience to which suspended lamps are liable, that
ing. of suffering the oil to run over, either by agitation, or from

rarefaction of the air in the reservoir by heat. Thus consists
in leaving an opening in the lamp at the top, so that het
temperature cannot influence it ; and it will always remain
at the same height.

♦ Chimneys made of the common blue glass of our glass houses, and
of the ordinary thickness, ■will not answer *, as I found by experience:
many yeat.s ago. At least they diminish the light in so great a degree,
that the consumption of oil to produce a given effect with them must be
so much more than with common glass chimneys, as to render them too
expensive for general use. W. N.

•f- This is evidentlj' analogous, hut I should suppose inferior, to Count
Rutnford's method of using ground glass. Sec Journal, Vol. XIV, p. 22.

He

SCIENTIFIC NEWS. ^C)

He.lifis likewise contrived vessels for keeping oil, so that Vessel foi*
when the oil is drawn off, its place is supplied by water at ^y^J|!^o"t thick-t
the bottom. Thus, the vessel being always full, the oil is ening.
not thickened by the action of the air.

A Course of Lectures on Natural Philosophy and the Mecha^
nlcal Arts. By Thomas Young, j\/. D,, For, Sec. to the
n. S., F. L. S., late Prof, of Nat. Phil, in the Royal In-
stitution of Great Britain, S^c. 2 vols. 4to. 1570 pages, 58
plates.

THIS valuable work has been for some time eagerly ex- Young"'s Natu-
pected ; but it has suffered no longer delay, than the co-
piousness of the subjects it -embraces, the great variety of
figures to be engraved, the large body of references, and the
accuracy required in every part of it, rendered indispensably
necessary. To give any adequate view of the multifarious
objects it embraces, would much exceed our limits ; we must
be content therefore with noticing them briefly. When Dr.
Y. undertook the office of professor of natural philosophy he
very properly conceived, that the plan of the Institution re-
quired something more, than a mere compilation from ele-
mentary works ; and therefore set himself to collect from
original authors, to examine with attention, and to digest
into one system every thing relating to the principles of the
mechanical sciences, that could tend to the improvement
of the arts subservient to the conveniences of life. In pur-
suing this course he has referred tlie fundamental doctrines
of motion to simply mathematical axioms, more immediately
than has been usual, and facilitated their application to
practical purpoies : very fully investigated the passive
strength of materials of all kinds, and formed many new
conclusions respecting it, of considerable importance to
the engineer and architect : simplified, extended, and il-
lustrated the theory and motions of waves, circulation of the
blood, and propagation of sound: investigated the curvature
of the images formed by lenses and mirrors : minutely exa-
mined the functions of the eye : copiously described and ac-
curately represented the phenomena of coloured light, and
pointed out some new cases of the production of colours :

reduced

go SCIENTIFIC NEWS.

reduced the theory of tlie tides to a simple form : inves-
tigated the cohesion and capillary action of fluids, in which
he has anticipated Laplace: made various comparative ex-
periments on the elasticity of steam, evaporation, iMO(^:,the
indicatioais of hygrometers : and interspersed much practical
information of various kinds, with new inventions and con-
trivances, that would take up too much room to enumerate.
The 'Jd vol. commences with the mathematical elements
of natural philosophy, comprehending every proposition re-
quired for forming a complete series of demonstrations, lead-
ing to ever}^ case of importance that occurs in the science,
except some of the more intricate calculations of astronomy.
But the greater part of it is occupied by what many will con-
sider as not the least important of the whole, a catalogue of
works relating to natural philosophy and the arts, metho-
dically subdivided as far as could be done with convenience
and accuracy. In this catalogue, works of superior merit
and accuracy are distinguished by asterisks, and those the
author considered as erroneous or unimportant by obelisks :
beside which he has pointed out those he has quoted ; and,
for the convenience of those who have access to the libraries
of the Royal Institution, Royal Society, Sir J. Banks, and
the British Museum, the books to be found in them*
Extracts to, and remarks, for the most part brief, are fre-
quently given, pointing out the leading objects, or affording
hints for farther investigation. In fact, such a body of in-
formation, and such a copious list of references to original
sources, condensed into a compass comparatively so small,
will not easily be found among the modern productions of
our press.

Lectures on CJicmlstnj.

Mr. ACCUM'S lectures on operative chemistry and mi-
neralogy, exhibiting a summarj^ exposition of the processes
of experimental chemistry, and general practical rules to be
observed in the performance of chemical experiments; to->
gether with a summary view of analytical mineralogy, exem-e
plifying the practical analysis of minerals; will commence
October 1st.

fLA^u-/uy6e?ij /y/f^j. 7ou'//ia/. Vo,

lMII.TUir.,

IZ 3 4-6

'III' 'I I I ' I IT

^3^

Scale ofInchej\

A

JOURNAL

OF

I^ATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

OCTOBER, 1807*

ARTICLE I.

Description of a correct Chamber Barometer. In tt Letter
from John Gough, Esq.

To Mr. NICHOLSON.

SIR, Middleshaiv, Aug. 17, I8O7.

ANY intelligent persons in the country have been pre- Correct baro-
vented from, entering upon a course of meteorological ob- meters not ea-
servations, by the want of good barometers ; which must be i^ the'^coumry.
procured from London, not without considerable risk. I
flatter myself, the present letter will remove this objection
to the study in a great measure ; for it describes an easy,
and perhaps original method of correcting the imperfections
of the instrument, and renders it fit for the purpose of every
meteorologist, whose pursuits and observations are confined
to his parlour or his study. When the correction in ques-
tion first occurred to me, some time ago, I communicated
it to Mr. Morris, of Kendal ; who made a barometer on the
principle explained to him, which has been some time in my
possession, and has fully answered my expectations. The
above gentleman also informs me, that any artist of moderate
abilities may be instructed how to construct an instrument
of the same kind, by a simple diagram properly explained:
VoL.XVIII— Oct. I8O7. G the

82 CORRECT CHAMBER DAROMETER.

tlie necessaiy instmctioris will accordingly be found in the
annexed figure, and description accompanying it ; which
explains the cause, that renders common barometers ini})er-
fect measures of the changes in the weight of the atmo-
sphere, and at the same time points^ out an easy and satis-
factory apparatus for counteracting this source of errour.
A correct Suppose A a (PI. IIT, fig. 1) to be the frame or outline of

chamber baro- ^]jg barometer, the ornamental part of which may be left to
meter describ- ,,..„, , , *

cd. the discretion of the workman : moreover let 28,31 repre-

sent a scale of 3 or more inches properly divided and fur-
^ nished with a nonius : let B C D E F be the compound

tube or inverted siphon containing the mercury ; it is her-
metically sealed at B, and open at E F ; the bore of the
longer leg B C is -^^ of an inch in diameter, and that of the
shorter D E F f |-, in the instrument from which the descrip-
tion is taken. When the siphon has been filled, it is to be
fi^ed to the frame A a, in such a manner, that the two legs
)5 C^ and D E F may have a vertical position. This being
^ done, a circle parallel to the horizon is to be cut on the ex-
ternal surface of the leg D E F at the distance of 31 inches
from the top of the scale, or 29f inclies from its middle, the
place of which is denoted in the figure by the line O o. It
The cause of will be perceived immediately that my barometer, as far as

maccuiacy in -^^ j^^^^ ^jg^^^ described, differs in nothing from the common
the common "

weather glass, weather glass: the imperfection of which ought to be ex-
plained to the less scientific reader, before the method of
correcting the instrument is described. In order to do this
!with the greater perspicuity, suppose, that when the tube is
first filled, the surface of the mercury in the leg D E F
coincides, as it ought to do, with the circle O o, and let the
surface on the other leg B C fall exactly on some division of
the scale, for instance 29 '5 : the weather glass will in this
case give the true weight of the atmosphere ; because the
■ length of the column of mercury in B C is exactly 29*5
.inches. But an instrument thus constructed will give the
Weight of the atmosphere falsely in all other instances : for
* let the length of the column in B C increase in consequence
of an increasing pressure in the atmosphere, it is evident)
that the surface of the mercury in the leg D E F will de-
scedd below the circle Oo; because the augmentation ii

tl)e

COilRECT CHAMBER BAROMETER. 83

the opposite column must be supplied by the branch D E F ;
let it then descend to the station H h. Now from the con-
struction of the weather glass here described, O o is the
only base from which we can measure the length of the mer-
cury contained at any time in C C accurately by the scale;
consequently the part of the column situate in H h and O o
will be neglected in the observation ; and the height of the
barometer will appear to be less than it really is by the space
H O; that is, the top of the column will not ascend so far
as' it ought to do above the middle poinl of the scale. On
the contrary, when the mercury descends in the leg B C it
will rise in the leg D E F, in consequence of a quantity o£
this fluid coming into it from the opposite branch. As oft
then as the weather glass denotes a height less than 29*5
inches, the surface of the mercury in the leg D E F will
ris6" above O o, the true base of the scale; consequently
when the column comes to be measured by the index, it will
appear longer than it really is by the height of the mercury's
surface jn the leg D E F above the base O o ; that is, the
upper Extremity of the column in the branch B C will fall
below the point 29*5, but not so far as it ought to do. Thus
it has been made evident, that the motion of the mercury
in the shorter leg diminishes the range of the barometer
when it comes to be estimated by the scale; which circum-
stance pointis out the necessity of a correction, and perhaps
the easiest method of doing it consists in bringing the sur-
face of the mercury in the leg D E F to a coincidence with
the base O o, before setting the index attached to the scale.
My apparatus for this purpose is nothing more than an ivory The method of
piston K of a cylindrical figure, about ]| inch in height ^^'■"^^""g ^lie
and I an inch in diameter. Its lower extremity is a little ther dass by %
convex and immersed in the mercury; it is also easily moved piston,
vertically by means of the handle or stem G L, which passes
through a cap covering the mouth of the tube E F, and
having a hole, 1, in its centre, wide enough to receive the
handle. iTh is part of the piston is also attached to the frame
A a by ia loop or socket of brass, L, in which it would move
lertically with perfect freedom, were it not for the pressure
or-ii bent spring which is situate between L and 1, and acts
ujthn the handle G 1, with a force, that keeps the piston iu

G 2 any ^

34- CORRECT CHAMBER BAROMETER.

Use of the pis- any position assigned to it by the operator. Tlie use of this
apparatus is almost too obvious to stand in need of an ex-
planation ; its office is to place the surface of the mercury
in the leg D E F on a level with O o, when an observation
is to be taken with the instrument. This is done by placinj*-
the finger upon G, and pressino- the piston downwards,
when the barometer is rising, which operation must be con-
tinued until the quicksilver coincides with ,0 o. On the
contrary, when the mercury falls in the leg B C, the piston
must be drawn up by means of the handle G L, so as to
produce a coincidence in the opposite branch of the tube,
A necessary similar to that just now mentioned. One circumstance must
thrconstruc- ^ attended to in the construction of the instrument ; for it
tion of the in is necessary that the middle of the piston K, which is mark-
b rumen . ^j ^j^l^ ^ dotted line in the figure, should coincide with
O o, as oft as the barometer stands at 39'5 inches. The
method of providing for this coincidence will be easily
pointed out by an example : suppose, when the tube is filled,
that the middle of the piston and the surface of the mer-
cury in the leg D E F coincide with O o, while the height
of the barometer is 29*00 or { an inch less than 29*5 ; in
this case, raise the piston until the mercury in B C stands
at 28*5, or as much below 29*0 as 29*0 is below 29*5 : this
being done, pour mercury into the leg D E F, so as to
make the opposite column rise again to 29*0, and the re-
quired coincidence will be provided for. On the other hand,
suppose the instrument to be adjusted as above described,
and the height of the barometer to be 30-0, or | an inch
above 29'5: in this case push the piston downwards, until
the column in B C stands at 30*5, or as much above 30*0 as
30*0 is above 29*5 : this being done, take a quantity of mer-
cury out of the leg D E F just sufficient to make the oppo-
site column fall again to 30*0, and you will have secured the
coincidence required.
Remarks re- I have observed in a preceding part of this letter, that the

specting the piston of my barometer is If inch in length, and ~ an inch
the piston. i» diameter ; but the reader is not to imagine, that these
dimensions are fixed by necessity, for they may be varied at
pleasure; and the following rule will determine the one,
wlien tlie other is given. 1st, When the diameter of tie

piston

ON THE PHYTOLACCA. 85

piston is given, multiply the length of the scale by the
squai-e of the internal dian«i|^r of the le<^ B C, and divide
the product by the square ojf the given diameter, and the
quotient will be the length of the piston : 2d. When the
length is given, divide the product found above, by the given
length, and the square root of the quotient will be the dia-
meter of the piston, hi adjusting these dimensions, we
have two circumstances of some importance to attend to ;
the quantity of mercury requisite to charge the tube in-
creases with the length of the piston, winch suggests a con-
sideration of an economical nature; but if the diameter of
the piston be too much augmented, to avoid expense, the
free motion of the barometer will be considerably impaired;
the artist must therefore use his own judgment in giving
those dimensions to the piston, which will be the most conve-
nient for the tube he is going to fit up.

I remain, Sec,

JOHN GOUGH. .

II.

Ohsefvattons on the Phytolacca^ or American Poke?veed; hy
Mr. H. Braconnot, Member of the Academy of Sciences^
Sfc. at Nancy*,

AN, who lays all nature under contribution, to increase T^e properties
his enjoyments, has availed himself of a i^reat number- of ° if ^"^.^"k^**

'J " r3 iciTldlu CO 06

vegetable productions; but, notwithstanding his extensive examiutd.
researches, he is yet far from being acquainted with the p'o-
perties that characterise the majority of plants. The Phy-
tolacca, which has been greatly neglected, may furnish an
instance of this.

Sect. I.
Tnchieralion of the phyfolacca.

THIS plant, which is acrid, has a very thick, fleshy root, Phytolacca.
^s big as a man's leg. Its stalks are as big as a large waik-
iiig stick, six or seven feet high, and purple.

•Abridged from the Annales de Chinile, Vol. LXXII, p. 71, April 1807.

If

85 ON THE PHYTOLACCA.

Stalk yields If a piece of the stalk be exposed to the flame of a cnn-

^° ^* die, it is reduced to a reticjJjir texture, exhibiting, when

viewed by a lens, a series of longitudinal filaments connected
by cross meshes. If t'nis be a^uin ejcposed to the flame, it
swells up, melts, and the result is potiash.

14 oz. troy in- Four woody stalks of this plant weighed wli,en dry 440

cmera e . graiti. [14 oz. troy]. These I burned in an iron crucible;
and when it began to grow red hot, the matter assumed a
_ paisty consistence, and ended by fusing, accompanied with
a swelling up occasioned by the evolution of hidrogen gas,
^vhich burnt with detonation qs it burst from the melted
matter. When the crucible was cold, it contained a hard
brown substance, that had a caustic taste.

Coal lixiviated. ' As it was impossible to get this saline residuum complete-
ly out of the crucible, I boiled water in it, and thus easily
separated it, great part of it being dissolved. The liquor

432 grs. of salt, filtered and evaporated to dryness left 28 gram. [432 gr.] of
a saline substance, which I saturated with pure nitric acid.
The liquor deposited a blue precipitate, which weighed
4 decig. [6 gr.]. This precipitate was not altered by mu-
riatic acid, and appeared to me to be prussian blue with a

A little silex. little silex.

In the solution saturated with nitric acid pure nitrate of

strontian occasioned no precipitate: but nitrate of silver

threw down some muriate of silver, which weighed when

8-6 grs. of mu- dry 22 dec. [34 gr.[. answering to 25 cent. [8| grs.] of mu-
riatic acid. • «.• * 1
riatic acid.

After having separated a little silver from tlie liquor by

means of sulphuretted hidrogen, I filtered, and evaporated

to dryness. Thus I obtained 33 gram. [510 gis.] of nitrate

270 grs. of pot- of potash ; containing 17*5 gram. [270 grs.] of pure potash

^^^' according to the analysis of Thenard. These 33 gram, of

potash contained no foreign matter, for they crystallized to

the last particle.

6 grs. of silex. The part insoluble in water being treated with nitric acid,

4 decig. [6 gr.] of silex were left. Carbonate of potash

110, grs. of tbrew down from the nitiic solution 13 gram. [200 grs.] of

^''"^' carbonate of lime; and the filtered liquor, being boiled, let .

A little magnc- fall a few decigr. of carbonate of magnesia And lime. It is

sia and lime, probable, however, that the lime, which constitutes the

ON THE PHYTOLACCA. 8/

greater part of the insoluble portion of the ashes, is not 1n
the state of carbqnate in the plant, but saturated, as well as
the potash, with another acid, which will be mcntijued pre-
sentl}'.

From these observations we may infer, that a hundred > 1 00 lbs. of asTi-
pounds of the ashes produced by incinerating the phytolacca^^S^''^® ^^^^^^»
will yield Gdj^lbs. 10 oz. 5 dr. of dried alkaline carbonate bonate of pot-
nearly pure, and containing about 42 lbs. of pure and caus- ^'^*
tic potash*.

Sect. II.

Examinaiion of the acid, tl^at neutralizes the potash in the ^
Phytolacca,

I BOILED 4| hectogr. [14§ oz. troy] of the ftesh woody 141 oz. of the
stalks of this plant in a quantity of water. The decoction
did not change infusion of litmus. On evaporating to a si-
rupy consistence, 1 gram. [15| ^rs.] of a salt confusedly yielded 15|grs
crystallized was deposited by stonding some time. Of this «^'»®"'=f^' ^^
the greater part was soluble in water, 2*5 decig. [3| grs.] of
a white powder remaining, which were dissolved in nitric
acid. With this .solution nitrate of lead gave a white' pre-
cipitate, which, dried and put on a red hot iron, gave a lit-
tle snjoke, and left a yellow oxide of lead, soluble in a weak
acid. . . ,

The soluble part of the sahne deposit did not afford any No* distinctly
very distinct crystals on being. evaporated, but a saline crust ^^^^ ^ '^
of a very pungent taste was formed.

This salt swells up and is carboiiized when exposed to the Swells np,

fire, and leaves as a residuum carbonate of potash. The f'"'""^' ^"^

1 1 1 -1 n 11 . ■ -1 . leaves carbn-

same salt, when heated with concentrated sulphuricaCid, is nate of potash,
blackened, and produces sulphurous acid. ; '- -sc'siiA

Lime water, and the nitrates of lime, strontian, and lead, Withirme,'
\ form white precipitates in its solution, which are insoluUlein jg^^j iusoluUe
distilled vinegar. . ; in vinegar,

• As potash diminishes considerably' iri vegetables in pvoj)ovtion as . .,->^l

liey api roach the wood> stat<^, it is prubable, that the phytalacca^wouJd - ■'*''^

aford a much {greater proportion of potash in an earlier stage of its

gywth.
\ These

88 ~ "ON THE PHYTOLACCA.

The decoction These experiments announced a del liquescent and diffi-
precipitatcdby <^"ltly crystal lizable salt in the phytolacca: and to separate
nitrate of lead, its elements, 1 diluted the decoction, which had been eva-
porated to a sirupy consistence, with a sufficient quantity
of water. To this I added a solution of nitrate of lead,
which formed a very copious precipitate ; and the filtered
liquor afforded an abundant crystallization of pitrate of pot-
ash.
Withsulphnric The precipitate, after being well washed and dried, weigh-
smplf oruree. ^^ ^ ^^"^- [77 grs.]. Being treated with a fourth of its
weight of sulphuric acid diluted with six parts of water, a
tolerably decided smell of uree exhaled from the mixture,
which had been exposed to a gentle heat on a sand bath ;
The acid U- and the liquor was filtered. What passed through was acid ;
quor. ^^^ ^^^ crystallize by evaporation or standing; and on con-

tinuing the evaporation a glutinous matter remained, yellow-
ish, attracting moisture from the air, and carbonized by a
stronger heat.
Farther exa- In this acid the nitrate of lead produced a very copious
miaed. flocculent precipitate ; and the precipitate, exposed to the

blowpipe, was immediately reduced to a globule of metallic
lead.

The nitrates of lime and strontian produced no percepti-
ble alteration in it, but ammonia occasioned a precipitate.

It precipitated lime water ; and the precipitate put on a
hot irou began by carbonizing, and left some ashes, which
dissolved with el'"'^rvescence in nitric acid.

What remained of the acid I saturated v;ith soda, but no

crystals were produced by evaporation. The result of this

combination, when heated in a crucible, burned, leaving a

light, alkaline coal, that efPervesced with nitric acid.

Analoeous to From i • e properties here mentioned, it appears, that the

the malic. gj^j^j of phytolacca has considerable affinity to the malic, but

]f>ointsin\vhrch with a few sha«'es of difference. With lime and lead malic

they differ. ^^.j^] forms i^occulent precipitates very easily soluble in disr

tilled vinegHr ; but those with the phytolaccic acid are in-

Perhaps inter- soluble. This acid may probably be a mean between tlie

mediat.: be- .'malrc and oxalic, or an oxit^enized malic acid ; but as it iS

tween th*' ma- -.,,.,,/ • n i

lie and oxalic. ^^^5^ abundant m the phytolacca, it will be easy to ascertan

this by farther examination of its saHne combinations,

' ' ^ On

ON THE PHYTOLACCA. SQ

On the contrary, sliould it prove to be malic acid, it would
be at least the first example of malate of potash found abuu-f
dantly as a natural production

Sect. ITI,

Exnjninatian of the colouring matter contained in the herries of
the Phytolacca.

The berries being bruised in a glass mortar with a certain The colouring
quantity of water, the filtered liquor was of a fine bright pur-
ple colour. I at first attempted to fix it on cloths, but soon
found its extreme fugaciousness.

The juice of the Ijerries has a sweetish taste, leaving be- The juice of
hind a sensation of acrimony, Paper tinged blue with lit-^^^ ernes.
mus, and wetted with water, was reddened when dipped into
it ; but the blue was restored without the least alteration by
washing with a little warm water.

At a moderate temperature it soon underwent the vinous Soon ferments,
fermentation. The wine produced was unpleasant to the ''''^^^^ ^^^» ^^^
taste, but brandy may be obtained from it by distillation. ^

If a few drops of lime water be added to the juice, it soon Lime water
assumes a fine yellow colour; but the smallest quantity of ^^^^^ ^^ ^^'
acid soon restores its purple hue. If the yellow liquor have Any acid,
sufficient colour to write with it, breathing on the paper will
change .the yellow letters to purple; and so will even expo-
sure to the air, though less speedily.

Sulphuretted hidrogen, or urine added in small quantity sulphuretted
to the yellow liquor, clianges it immediately purple. hid.ogen, or

The deep yellow liquor produced by the combination of "/jg'pj^^p^jg^^''^*"^
the purple of phytolacca with lime grovv^s lighter by the ad- Water dilutes
dition of water, and assumes the tint of chromate of })otash. the yellow, and
But if the quantity of water be still increased, the oriuinal I", j""^^^, ^"^"'

*■ •^ O Illy Ifc^SlOr&i

purple reappears. At fust I ascribed this effect to the car- t-^^e purple.
bonic acid, that might be contained in the water; but water
long boiled exhibits the same phenomenon. Hence I infer,
that water acts by weakening the effect of the lime in the
yellow liquor, which occasions it to return to purple.

From what has been said it appears, that the yellow li-
quid affords a verj delicate te§t of the presence of acids; ofaciir:^ ^^"

and

00 ON TUB PHYTOLACCA.

ttfid n c6mpaiative experiment with litmus will corroborate

this. Into two glasses I put equal quantities of the juibe of

Phytolacca, which I had turned yellow by a few drops of

lime water : and into the two otl.er gkisses I put an equal

weight of infusion of litmus, of an equal depth of colour.

More than 6o drops of a very weak acid were required to

redden the infusion of litmus, but less than 15 restored the

purple colour of the yellow liquor. Hence it follows, that

the yellow liquor of phytolacca is at least four times as sen-

tjttt. does not ^ible as the jnfusion of litmus ; but the yellow liquor being

keep. extremely fugacious, it cannot be kept, or even used but just

after it is prepared. A few hour^ are sufficient to char.ge it.

Its spontaneous First a fallow precipitate falls down, which, looked at in the

changes. ^^^^ exhibits very small scales with the various hues of the

opal. After a few days brown flocks separate from it. The

properties of the reagent are then entirely destroyed, and at

length the liquor is almost wholly deprived of colour.

The following are the results produced in the purple liquor

by other reagents.

Caustic alkalis give it a yellow colour. Alkaline subcar-

bonijites, a fine violet, that fades, and becomes yellow, by

Fff cts of re- standing. AVeak atids, nothing perceptible. Dilute oxi-

apents on the genized muriatic acid, a complete deprivation of colour, with

purple liquor, ^.j^j^g flocks. Aluiii, uothing apparent on mixing, but after

some days ^, very light red precipitate. Muriate of lime, no

change. 31uriate of tin, a red sediment inclining to lil^c,

and leaving the supernatant fluid colourless. Nitrate of

lead, a precipitate of the colour of wine-lees. Superoxided

sulphate of iron, a dirty violet: and on adding au alkali a

very deep green precipitate, changing yellovv by exposure to

the air.

The purple colour that tinges the epidermis of the stalks

of the Phytolacca is precisely of the same nature as thatcon-

Tv.. » t •„ tained in the berries, and atlordcd the same results.
The colouring

TuattcTofthe I have convined myself, that this purple does not arise
sulks the same. ^j,^jj^^ tiie alteration of any colour by au acid: for having

chanued it ytdlow by animouia perfectly freed bom carbonic
Not a colour "^ ♦ •' . , , : . i i r

altered by au acid, impregnated hneu with this, and exposed the linen to a

*^^'^' moderate temperature excluding the air, the purple re-

appeared in all its lustre as the ammonia was volatilized.

This

ON THE PROTEUS. ANGUJN US.

91

This colour is different therefore froip that of some other

fruits, as the plum uud cherry, which becomes green on the

addition of alkalks ; and from that of litmus, which alkalis Differs from

turn blue: but it appears to have some analogy with that of ^'^^r^*^ j"'c«*
^•^ 1 • f. T 11 of some othef

the grape, as Imie water turns red wuxe ot a dirty yellow, ,,: it.

which acids change again to red. ■■ Analogous ti9

that cf the
grapQ.

Sect. IY.
Other properties, and cultivation of the pliytolacca.

In North America the leaves are boiled, and eaten as spi-
nach, and 1 have found them very good*. Thp juice of the jfg leaves es
root is a purgative, and may be taken in the dose of a table- lent.
spoonful or two ; but must not be used when there is any Juice of ihe
inflammation of the viscera. The narcotic virtues, that have ^ «» *
been ascribed to it are illusory, as Lemery observed.

It may be propagated by seed, sown in the spring in light
ground, and transplanted to a dry soil, which should be dug '*'
very deep. When the plants have taken root, they require
no care, but to be kept free from weeds. The stalks die
with the first frosts, but the roots are 'perennial, and throw
out shoots in the spring for several years.

III.

A Memoir on the Proteus Anguinus; by Baron von Zoisf.

Ji- HE proteus anguinns is found in Carniola, between

Sittich, an ancient monastery about eight leagues from hi-Aj- Where found*

bach, on the roud to Neustadt, and a small village called Vir

in the Sclavonian language, and Weyer in German.

* Th^ young shoots are said to be as good as asparagus. Tr.

•f- Translated from the Italian manuscript of Baron Zois by Mr.Siauv'e,
commissary at, war; and inserted in tiie Magazin Encyclopedique for
January, 1807, p. 59 j whence this article is taken.

The

9<J| ON THE PROTEUS ANGUINUS.

Geology of the The rock tliat composes the hills of Sittich is a compact,
place, stratified, calcareous mass, rising in t4ie centre of our Alps

to the height of 1500 toises above the level of the Adriatic ;
and the geological character of which is to be interspersed
with funnel-shaped hollows on the surface, and grottoes and
caverns internally.

At the foot of a part of this calcareous rock, at the bottom
of the valley of Vir, are two openings or mouths of grottoes,
15 or 18 inches in diameter, 3 or 4 feet above the surface of
the ground, and about 12 feet distant from each other.
From each of these a stream of cold and limpid water flows
into a small basin beneath, which is afterward lost in the
Seen only in ground about 750 paces beyond the village. The amphi-
twobiisin>, bious animal in question has never yet been found in Car-
supplied from .7 •' • 1 -J. •
subterraneous niola, except in tlte^e two oabins : and as it is never seen m

cavrns, and them, except on the melting of the snow, or after heavy

tions. ' rains, it is supposed, that the overflow lag of the subterranean

reservoirs, to which they belong, drives them out. The pea-
sants of Vir, who know tiiem oy tradition as well as experi-

Popular names, ence, call them bela riba, wlvite tjsl>, or zhioneshka riba^ tish
that has soujethiug ; uman. The latter naine alludes to the
joints Oi their toes, or ringers, aiid viic colour of their skin.

By whom no- The animal was. tirst made known to the public by Dr.

iiced. Laurenti, in his Sijrwpsis ReptUiKm^ in 1/68. He gave jt

the name of proleus anguinus. Scopoli, who saw it alive,^
gave a fuller description of it in 177-ij io l''s Anims Quiutus
Htsforico-Naturaiis. He says, that L nneus, to whom he
sent it, considered it as the larva of a lizard ; but hettiought

Linnetis?iT?- it a distinct genus. Linneus however expressed himself

pected It to be cloubtingly both on this and the proteus tritoniusofSchianck,
found in lakes in tlie interior parts of Austria ; leaving it to
accurate and repeated observation to decide, whether or not
they underwent a transformation at a late period.

To forward the solution of the problem, Baron Zois sent
several specimens of the proteus anguinus preserved in spirit
to Dr. Scnreiber, professor of natural history at Vienna, that
he might dissect them. The anatomical description is given

«' at length in the Philosopliical Transactions for 1801.

Its ar!alQ«*v to '^'^ principal analogy between the proteus and the larvae

larvae of some of some amphibia, which has occasioned them to be con-
founded

a larva.

Dissected.

ON THE PROTEUS ANGUINUS. Q.^

founded*, consists in tlie "ills common to both. Mr. Schvelber amphibia in
liovvever observes, that the pills of the proteus differ essen- _.„''
tially from those of larvre and fishes by their red colour,
ovvinj^ to the blood which it causes to circulate through th'em
more or less abundantly at pleasure.

As to the organs of respiration, Mr. Schreiber asserts, that,
having dissected a great number of laryic of aquatic lizards,
he never found the leasit analogy between them and the pro-
teus. He considers it as more allied to the siren lacertina, Moreanalo- ^
both having gills and lungs; though Camper indeed denies fealacertinar
the existence of limgs in the siren. It is true Mr. Schreiber
observes, the siren differs in having but two feet; a short j)j|^gj.gj^j,g5^
head without any beak ; a small, pointed mouth ; eyes very
apparent, and eyebrows ; and the lungs, though equally Lun«Ts.
formed of one single membrane, without any cellular divi-
sions, running along both sides of the body, and exhibiting
neither the various turns nor the very remarkable bladders
found in those of the proteus.

That Mr. Schreiber found it difficult to discover and as- tac: ^^ .

Difficult to as-
certain all the parts of t!ie organization of specimens, that certain its

had been kept a long time in spirits, is not at all surprising. P^*^^^"

He observed ovaries however, and even something that had Apparently

the form of a uterus: but he lays no great stress on these ovaries and a
T 1 X ^ o uterus,

slight appearances.

I hope however he will be able to decide the question, by
means of the d'ssection of some individuals, which I have
found means to send him alive. The basins at Vir had fur- Only from 3 to
nished only three, four, or five in a year since 1798 : but on 5 found in a
the 26th of December, 1804, on the thawing of a deep snow, ^'^^*
fourteen w^ere brought rae at once. These are at present at Once U.
Vienna, some of them uiider the e^'e of Mr. Schreiber, and
others in u subterraneous canal, under circumstances the

• The question appears at present decided, and the protei are consi-
dered as a di'-tinct genus Beside the ang'unus, which had already been
figured aad described, but of the mannep and habits of which Baron Zois
gives here new and interesting particulars, and the tritonius of Schranck,
Humboldt and EonpJand observed another species in Peru, the skin and
limbs of which perfectly resemble those of the salamander.

most

^4* ^^ "THE PROTEUS ANGUINUS.

tnost favourable for their nourishment, and for their breed-
ing, if they be capable of it*.
Manners. As to the manner of living of the proteus, whether it be a

perfect animal or not, its principal eharact'^r is a very decided

Strong antipa- antipathy to daylight. Expoyed to the sun it is agitated in
thy to light. ,. ' , . '

an extraordmary manner, and makes continual efforts to es-

No external <^^pe. Yet it has no eyes externally, or, as Scopoli asserts,
eyes: £vvo tubercles in the place of eyes. Mr. Sthreiber first dis-

Vuttwoundsr- covered its small, black, subcutaneot-s eyes, which are per-
fieath the skin, ceptibte sometimes, though but rarely; and this only in in-
dividuals that have grown lean by forced abstinence, and the
epidermis of which is become very thin.
Mo"re«;bv ^" ^^^ movements under water the proteus sometimes em-

fneansofits ploys its paws, or feet; at other times its tail, in d-fferent
slowh'^^ ''^ ' manners. Its progress is slow and circumspect : but when it
When offend- ^^ irritated it flees with swiftness, and with a siouoiis motion
ed quickly and ^\q an eel. In this case it makes no use of its feet ; and as
those behind might impede its velocity, it keeps them close
Conceals itself *^ *^^ bod)% During the day it likes to keep itself concealed ,
in the day : and Seldom changes its place : by night on the contrary it is
at nig ^^'^"^O" aiyvays seen moving about at the bottom of tlie water, and

' frequently attempts to get out.

Takes no food Those t! at are thus in captivity would never toudi any of
in confine- the food offered them, such as fresh eggs of fishes, fibres of
*"^"^* fishes or frogs, aquatic worms, polypi, conferva, &c. ; pot

even the helix tliermalis, though it is certain in a state of
liberty they swallow a great number of these testaceous ani-
mals ; for I have found as many as eighty-four of their
shells in the excrements of a well fed proteus, which he dis-
charged at three times the second day of his captivity.
When living ones were given him, he took up one with hi*

Receptacle * The nrchduke John has had a subterranean canal constructed of tufa-

formed for ^ stroam yf spring water runs through the sinuosities formed in it, and

theni by the ^jj^ ^^^^ diflferon\ basins, in which the protei are. A snttne was selected,
Wehduke. , ',.,.. , , < , • \. , ,

the waters of v.hich contam insects ada^>ted tor then- food j and means

jhave been contrived for inspecting the little colony, when it may be
thought time. It is to he wished by tlie epicure, that the protei may
irced, for l[ieir flesh is vrbitc, delicate, and of an exquisite flavour,
as 1 have been assured by Baron Zois, -who has eaten it. Note t^f
Mr. Siauife,

mouth

O-N THE PROTEUS ANGUINUS. 9 J

month, but Immediately threw it out to the distance of two
inches. Afterward he chose rather to leave them to breed,
than to taste them.

NotwitJjstaJidiug' this obstinacy in refusing all kind of Lives fi long
food, these animals live a long time in pure water, if they ''^^^^^^ "^ ^^^^
be kept in the shade in wooden tubs 15 or 18 inches high,
and as mucli in diameter; and if the temperature of the
water, which ought to be changed every four or five days,
do-not exceed S® of Reaumur [50° F.]. Put into cold wa- about 50«'F,
ter in which snow was floating; I have seen them experience
painful sensations, manifested by their agitation, and die
within four and twenty hours.

AVhen put together they appear to know one another, for Know one ajwv
the new comers soon grow familiar with the old ones, and
sometimes even utter a gentle cry, that seems to indicate Utter a cry of
their satisfaction*: on the contrary, when they are offended ^^'^t'^fact'^^S

. and a hiss of

by the curiosity of the spectators, or the appearance of the displeasure,
sun, they hiss with a liarsh tone, very different from the pre-
ceding, and at the same time emit bubbles of air from the
mouth and gills. The degree of their agitation raa}"^ be dis- Express of,
tinguished by the greater or less tumefaction of the branchy ^'^}'>^^ ^Y ^^^®*f
plumes that rise from tlie gills, as well as from their colour,
which in this state assumes a fine crimson. If these plumes
be then viewed with a microscope, they resemble branches
of coral ; but when the animal is tranquil they fall, become ^
flaccid, and are of a livid white.

^ With a lens of moderate power the systole and diastole Circulation of
[ ©f the pulse may be perceived in these plumes, the branches fa'^the'^^Js^®*

c.

♦ The proteus appears to possess the sense of feeling in an eminent
j^egres. 1 have- often been pleased to see it pass its little hands over
ipthers of its own species.

Howpver this muy be, the rcoeniblance of its fore paws to the Immari
hand, the fine carnation tint of this pretty animal, the transparent epi-
dermis that may be compared with that which covers the person of a
handsome woman, the sort of amorous cry it utters when it has a com-
panion given it, have thrown me more than once into a revery., I know
not whether the proteus possess more than ordinary intelligence ; buf
every thing, even to its obstinacy iu refusing all kind of nourishment,
interest me in favour of t\mjish-man, ^s the Carniolians call it. AVe of
Mr. Siauve,

of

96 ON THE J»ROTEUS ANGUINUS.

of which are so nidriy tubes ; and the red globules of blood
may be seen to ascend and descend at each pulsation^ I
have counted from forty-five to forty-eight of these pulsations
in a. minute.
Out of the wa. Out of the water the proteus cannot proceed more than
to the ground^ ^ ^^^ ^^^^' ^^^ *^^® glutinous substance, with which it is en-
anU dies. veloped, soon dries, and g]ues it to the ground by the pait

on which it drags itself along. Several of mine died in this
state. Having found one thus, that had still some signs of
life, I separated it with my hand ; but it died two days af-
ter, having a red streak, indicating inflammation, along the
side which had adhered to the ground. Others after it,
which were separated by means of warm water, continued
Before death to live. In all that died under my inspection I observed an
their slimy jnfalHble sii^^n of approaching- death : the eluten, with which
coat separates. ^, i 1 • . . r .i i i ^ i

they are covered, begins to separate Irom the body, and be-
comes visible in the water ; it floats about them in flocks,
attaching itself particularly to the paws and tail ; at length
they turn on their backs, and soon come to die on the sur-
face of the water.
Size from 7 in. The annexed figure of a proteus anguinus drawn from
to 15, by 6 or nature, PL III, fig. 2, gives an accurate idea of its exter-
nal form. With respect to size, they have been found from
seven or eight to twelve or thirteen inches long, and even
fifteen or sixteen ; and in diameter from six to eighteen lines*
These dimensions do not agree with those of the aquatic sa-
lamander, and there is no other reptile in Carniola, that can
be compared with it.
Three have ^ have at present three, that have lived in pure water two

been kept 28 years and four months. They have grown thin, and dimi-
mont s. nished in size one half; and the fin that forms the tail even

appears to be shortened : yet they are in perfect health. I
shall not fail to observe^the duration of their lives ; though
I begin to persuade myself that the vague term, which Lin-
neus expresses by the words transformation at a late period,
is already past.

IV.

SUPPOSED ANTIQUE EMERALD, - §7

IV.

Account of the Antique Vessel, that was preserved at Genoa
under the name of ^kc^q Catino, and reputed to be dn
Emerald; tvith the Report made of it to the French Insti*
iuie, August 4, IS06, by Mr. Gv^iTos*,

Disli of an liexagorial shape had long been in possession Sacro Catino.
of the city of Genoa, which was supposed to be an emerald,
and consequently of inestimable price. Farther to enhance
its value, according to the legend it was the very dish, on Legend re-
which the paschal lamb was served up, when Christ cele-
brated the passover with his apostles, afterward miraculously
converted into an emerald ; though sOrae will have it to have
been originally an emerald, and among the presents of the
queen of Sheba to Solomon. Neither is it agreed in what Brought from
manner it came into the possession of the Genoese; as some ^*^*

say it was their part of the booty found at the taking of
Caesarea in the first croisade^; others, that it was presented
to them by Baldwin king of Coi^stantinople. It was so MoTtgaged for
highly valued, however, that at the siege of Genoa in 1319, 1200 marks of
it was mortgaged for 1200 marks of gold, and redeemed ^'^ '
eleven years aften

An act passed in 1476 to prohibit its being touched with Suspicions of
gold, silver, gems, coral, or any other substance, under very its being glass.
heavy penalties, and even in some cases pain of death,
shows, that suspicions of its genuineness existed. William
of Tyre is the first wq know, that expresses such a suspicion.
Barthelemy observed in it blebs, which induced him to think
it glass. Condamine too, examining it by torchlight, and
at some distance, could not perceive in it any of those clouds
or defects of transparency, that are common in emeralds as
well as in all gems of a. certain size ; yet he evidently dis-
cerned several small vacuities, resembling air blebs, both
round and oval.

*► Abstracted frojtn Mag.. Encyciop6dique, January, 1807, p. 137',
and Annales de Chimie, Vol. LXI, p 250, March, 1807.

Vol. XVIII—OcT, I8O7. H At

98

Remorcfl to
Parij, and ex;a«
xnmed.

Its fi^rc

Col©ur,

Has blebs.

These marks
doubtful.

Sped. grav. not
exami/ied.

Hardness.

liUPPOSED ANTIQUE EMERALD.

At length this vessel having been transferred to the impe-
rial library, the Institute was requested by the ininibter to.
ascertain its quahty ; and Haiiy, Vauquelin, and Guyton,
were accordingly appointed to examine it. What follows is
the substance of Mr. Guyton's report.

Its diameter, from one angle to another, is 39*143 cent.
[15 in. 2 1. Eng.], its depth within 12*357 [4 in. 8 1.], iU
height, including the foot, which is of the same piece, 1 6*476
[6 in. 4l.]. It has two handles, likewise formed in the same
piece, without any appearance of having being joined to it
after it was made. One of these is broken. The bottom ap-
pears to have been wrought on the wheel, so as to form a cir-
cle of small cavities, whence issue six rays, corresponding to
the angles. PI. Ill, fig. 3, is an exact representation of the
bottom ; fig. 4 shows it standing on its foot, and fig. 5 in-
verted, with the position of its handles, which are placed so
as to be concealed, yet in a manner to be taken hold of ea-
sily.

The colour of the dish is an olive green, duller than that
of the peridot, with something of a greasy cast, that brings
it nearer to the plasma of the German mineralogists, than
to the green emerald of Peru, or the bluish emerald, or
aqua marina, of Siberia. Its transparency participates of
this tint.

On holding it up against the light, a bleb about 2 millim.
['78 of a line] is distinguishable near the centre, and farther
off some very small blebs.

It would be difficult from this description to infer the na-
ture of its substance, since it is now well known, that the
colour of gems of the same species varies considerably, and
that rock crystals exhibit blebs interiorly, which we cannot
always distinguish with certainty from those in glass.

We could not conveniently examine its specific gravity,
on account of its size : and besides it would have been to
little purpose, as the specific gravity of the emerald does not
much exceed that of common glass, and is inferior to that of
a glass loaded with metallic oxides.

We ascertained its hardness, however, which is a less
equivocal character of gems ; and found it very evidently
scratched not only by the emeralds of Peru and Siberia,

but

SUPPOSED ANTIQUE EMERALD. QQ

but even by rock crystal. This would be sufficient to de- Not an eme-
cide, that it could not be a real emerald, if the enormous ^* *
block, from which such a vessel must have been cut, would
r.ot be a phenomenon, that nothing hitherto found in nature
renders probable.

It is a manifest errour in Dutens, to admit among the va- Mistake of
rieties of the Peruvian cmeryld a stone that can be touched ^'^'®"^'
by the file. Those of the environs of Limoges, which are
scarcely transparent, scratch flint.

The largest emeralds known, before the discovery of the Largest erne-
colourless emeralds in the department of Hautc-Vienne, '''^'^*^"°^"*
and mentioned in the inventory of the Garde-Meuble, the
catalogues of DaS'ila, Daugny, &c., and those that Conda-
mine saw at Rome, which he considered as enormous, did not
exceed 10 or 12 cent. [3 in. 9 1. or 4 in. 7l.] long, by 3 or 4
[1 in. 2 I. or 1 in. 61.] broad. Even those-of the commune Those of
of Bessines have yet afibrded only masses of 30 or 40 cent. France.
[11 in. 71. or 15in. 61.] high, by 15 or l6 [5 in. 8l. or6in*
21.] thick.

We may judge what would be the value of the dish, if it
were a real emerald, by taking the rule of its being worth
one fourth the price of a diamond of equal weight.

What has been said is sufficient to authorise us to con- A5 it is colour-
elude, that the substance of the dish cannot be considered *^ S^^^^ ^' ''S
as an emerald, or any other gem, but is coloured glass. I^a"n antique.
We leave to others to determine its value, either as a work
of art, or as an antique; and whether it may be identified
or compared with that which Herodotus says he saw at
Tyre, in the temple of Hercules. We shall only observe,
that the art of imitating gems by coloured glass dates from
remote antiquity. Pliny speaks in several places of these
false stones, and points out the method of distinguishing
them, by trying their hardness against others.

H 3 0

100 ON THE CUXTIVATION OF SEA KALE.

V.

On the Cultivation of the Cramhe Maritima of LinncuSj or
Sea Kale. By Mr. John Maher, F. H. S.*

Culture of sea -^ F the man wlio malces two blades of grass grow where
"^^ only one grfew before, is to be esteemed an important bene-

factor to his country ; he who teacher us how to improve a
jialatable and nutritious vegeta1)le, hitherto often negiected,
upon the barren cliffs of our sea-girt isle, has surely no small
claims to our gratitude: as such, I must ever regard those
improved by of the late Mr. Curtis, from whose pamphlet upon the
Cramhe Maritima, or Sea Kale, I first learnt how to grow
this early esculent; but as his useful directions are yet in
the hands of comparatively few of my brother gardeners,
Verv fine pro- ^"^ ^* *^^ young shoots have been obtained at Edmonton
duced at Ed- of a size and delicacy greatly superior to what generally
monton. appears at the table, I venture to offer a particular account

of the method of cultivatiiig it there to the Horticultural
Society.
Places where ^^^^ particular places on record where this plant grows
fbuo^Y?!.**' wild, are below Maryport ; also between Ravenglass and
'^: \ ' 5oof/e, in Cumberland ; at Jiooseheck, in Low Furness,

"'^' "" '" Lancashire; near Conumy, plentifully, but in the most in-
accessible rocks; promontory of Llyn, and near Cruccaethf
in Caernarvonshire; between Rhuddgaer and Llandwyn, in
the isle of Anglesea ; about Port Inon, in Glamorganshire;

Mr. Curiis.

near Mcgavissey, in Cornvvall ; marly cliHs, near TeigU'
mouthy and Sidmouth, in Devonshire ; on Chesil Bank, chalk
cliffs at Weymouth, lAilworth Cove, and about Poole, in
Dorsetshire; at IFestern Court, in Hampshire; near Wor-
thing and Shoreham, cliffs at Beachy Head, and near Has^
tivgs, in Sussex ; between Folkstone and Dover, at St. Mar-
garet's and Laugdon Bays, between Whitstable and the hie
of Thanet, at Lidde", in Kent ; near Harwich, in Essex ; on
the north coast of Norfolk^ abundantly; near Fast-castle,

• From the Transactions of the Horticultural Society of London,
!';>. I, Part I, p. 13. For an account of the- objects of this society see
Sffxirnal, Vol.XlV, p. 150.

Berwickshire.

ON THE CULTIVATION OF SEA KALE. XOl

Berwickshire. According to Dr. Smith, sandy shores are Natural soil, r

its natural soil, but by what I can learn from others, as well

as my own personal observation, it prefers loamy cliffs, rnixed

with gravel. I found it near Dover ^ also in Sussex, in stiff

loam : to the extensive beach of pure sand, both above and

below Scarborough, in Yorkshire, it is, i believe, quite a

stranger.

The whole plant is smooth, of a beautiful glaucous hue, Desfcriptiou.
covered with a very fine meal ; occasionally, however, it va-
ries like the wallflower-leaved ten weeks stock, with quite
green leaves. Root dark brown, perennial, running deep
into the ground, divided iiito numerous wide spreading
branches, but not creeping* Radical leaves very large,
and spreading wide upon the ground, waved, more or less
slnuated, and indented, containing: a bud, or rudiment of the
next year's stem at the bottom of the leafstalk, dying away
in the autumn f. Stems several, from one foot and a half • -

to two feet high, erect, branclsing alternately, and terminat-
ing in large panicles of spiked flowers, which smell some-
what like honey. Peduncles, as the fruit swells, consider-
ably elongated. Calyx often tinged with purple, its leaflets
nearly equal. Petals cream coloured, with purple claws,
larger than in many geaera of this natural order. Filaments-
purple. Anthers pale yellow. Glands of the receptacle
between the longer filaments yellowlah green. Stigma pale
yellow. Pouch, as the accurate Mr. Woodward describes it
in Wltherjng's work, at first egg-shaped, afterwards nearly
globular, fleshy, falling off when ripe, about August, with
the seed in it, which is large, and of a pale brown colour.

* Rojt not creeping, in the proper*sense of that word, as Parkinson,
MUlfer, and Bryant have described it ; but if the branches be divided
into a number of pieces, each piece \Vill grow if ccJ^mmitted to the earth ;
ai:d a'^ it is impossible to dig among the widely extended lOots of these
plants without cutting many of them, and leaving a number of fragment?,
plants arise from such around the original, and give to it the appearance
of having creeping roots. Cort.

"f- Parkinson perhaps nevor committed a more egregious blunder, than
in the account he has g'%'en of this part of the plant's economy ; ** Th e
root iff sometohnt great, keejungf the green leaves all the ic inter.'''' Bryant,
in his FL JJi<Et. misled, i)erhaps, by this account, says, *' The radical
haves bting green alt Ike ivinler, nre cut by ihe inhabitants where the
pUnt grows, and boUed<u Cabbage. C\'RT.

The

IQ^ ON THE CULTIVATION OF SEA KALE.

Exported 200 The Crambe Maritima was kaowii, and sent from this
year* ago. kingdom to the continent more than two hundred years a^o,
by rObel, and Turner*; but our immortal countryman.
Miller aoticed Philip Miller, has the honour of being the first who wrote
*^* upon it professionally, as an e^calent, telling us, in the first

edition of his Gardener's Dictionary, published in 1731,
that the inhabitants of Sussex gather the wild plant to eat
in sjring, soon after the heads are thrust out of the ground,
otherwise it will be tough and rank. Prcfessor Martyn,
next, in the last edition of the same work, has printed some
valuable additional instructions, how to cultivate this plant,
frem the M S. of the Rev. Mr. Laurent. Lastly, the late
celebrated Mr. Curtis has done more to recommend it, aad
difi'use the knowledge of it, in the dissertation above quoted,
than any of his predecessors.
Mode of cul- To grow this vegetable in the highest perfection, prepare
t^ire. the ground in December or January, by trenching it two

feet and a half deep; if not that depth naturally, and light,
it must be made so artiticially, by adding a due proportion
of fine white sand, and very rotten vegetable mould. If your
ground is wet in winter, it must be efTectually drained, so
that no water may stand within a foot at least of the bot-
tom: for the strength of your plants depends on the dryness
of the bottom, and richness of your soil. Then d'.vide the
ground into beds, four feet wide, w-th alleys of eighteen
inches, after which, at the distance of every two feet each
way, sow five or six seeds two inches deep, in a circle of
about four inches diametei; ; this operation must be per-
formed with strict care and regularity, as the plants are af-
terwards to be covered with the blanching potsf, of which

a drawing

• It would be difficult to ascertain the precise period of its being first
used with us as a culinary plant ; on many parts of the seacoast, the
inhabitants for time immemorial have been in the practice of seekir.g for
the plant in the spring, where it grows spontaneously ; and, r'^nioving
the sand or pebbles, they cut off the young shoots as yet blanched, close
to the root. Mr William Jones, of Chelsea, saw bundles of it in a
cuitivatod state, exposed for sale, in Chichester market, in the year 1 753.

CUBT.

-f It appears to me, that for forcing, it would be a great improvement
to mak« the blanching pois.in t'vq pieces, the uppt'-rmost of which

should

ON THE CULTIVATION OF SEA KALE. 103

a drawing is annexed, PI. Ill, fi^. 6, and both the health
and beauty of the crop depends upon their standing at equal
distances. In the months of May and June, if the seeds
are sound, the young plants willnappear. When they have
made three or four leaves, take away all but three of the
best plants from each circle, planting out those you pull up
(which by a careful hand may be drawn with all their tap
root) in a spare bed for extraforcing, or to repair accidents.
The turnip fly and wire worm are great enemies to the whole Wire worm
class of tetradynamia plants. I know no remedy for the *"^ turnip fly.
latter, but picking them out of the ground by hand ; the
former may be prevented from doing much damage, by a
circle of q-uick lime strewed round the young plants. If
the months of June and July prove dry, water the whole
beds plentifully. In the following November, as soon as
the leaves are decayed, clear them away, and cover the beds
an inch thick with fresh light earth and sand, that has laid
In a heap and been turned over at least three times the pre-
ceding summer ; this, and indeed all composts, should be
kept scrupulously free from weeds, many of which nourish
insects, and the compost is too often filled with their egg^
and grnbs. Upon this dressing of sandy loam, throw about
Rix inches in depth of light stable litter, which finishes every
thing to be done the first year.

In the spring of the second year, when the plants ^re be- gd year,
ginning to push, rake off the stable litter, digging a little
of the most rotten into the alleys, and add another inch in
depth of fresh loam and sand. Abstain from cutting this
year, though some of the plants will probably rise very
strong, treating the beds the succeeding winter exactly as
before.

The third season, a little before the plants begin to stir, q^ geason.
rake off the winter covering, laying on now an inch in depth
of pure dry sand, or tine gravel. Then cover each parcel
with one of the blanching pots, pressing it very firmly into
the ground, so as to exclude all light and air; for the colour
and flavour of the Sea Kale is greatly injured by being exr

shoul4 fit like a cap upon the lower j the crop might then be examined
without UUturbinit the Ivjt Uung. Secr.

posed

104 ^N '^^^ CULTIVATION OF SEA KALE.

posed to either. If the beds are twenty«-six feet lon^, and
four wide, they will hold tweaty-four blanching pots, with
three pUnts uud<?r each, making seventy-two plants in a bed.
Examine them from time to time, cutting the young stems,
when about three inches above ground, carefully, sa as not
t<C). injure any of the remaining buds below, some of which
"will immediately begin to swell; in this method, a succession
of gatherings may be continued for the space of six weeks,
after which period the plants should be uncovered, and their
leaves suft^red to grow, that* they may acquire and return
nutriment to the root for the next year's buds. The flowers,
when seeds are not wanted, ought to be nipped off with the
finger and thumb, as lo!)g as they appear. If a gentleman
does not choose to be at the expense of the blanching pots,
the beds must be covered witii a larger portion of loose gra-
vel, and mats; but the tim^ and trouble of taking away the
gravel from about (he plants to cut the crop, and replacing
it, is so-great, that there is no real economy in' it. In this
way Sea Ka/eh-ds been put in Mr. Beale's garden, which
10 to 12 inches iTieasured ten, eleven, and even twelve inches in circumfe-
circumference, r^nce, and upon an average each blanching pot affords a dish

twice in a season.
Forced with ^o vegetal>le can be so easily forced as this, or with §o

little expense little expense and trouble; for the dung is in the linest posr
sible order for spring hot-beds, after the Sea Kale is gathered.
The only thing necessary, is to be very particular in guard-
ing against too much heat, keeping the temperature under
the blanching pots as near to iifty-five degrees of Fahren-
heit's thermometer as may be, but never higher than sixty.
For this purpose, in November and December, according as
you want your Sea Kale^ prepare a sufficient quantity of
fresh stable dung, to cover both the beds and alleys, from
two to three f(^et high ; for in the quantity to be laid on, a
great detil must always be left to the good senge of the gar-
dener, and the mildness or severity of the season. . It should
be closely pressed down between the blanching pots, placing
heat-stiok^ At proper intervals, which by being examined
occa!5iona]ly will indicate the heat below. After the dung
Worms, has remained four or five days, examine the pots. Worms

often spring above the sur^ce, arid spoil the delicacy of the

young

ON LARD, AND COMPOUNDS MADE WITH IT. iOv>

youns; shoots : the best remefly against which 13 to corer
with dry sea-coal ashes, sifted neither very small nor very
large ; salt also e^ ectually destroys them, and will not in-
jure the Sea Kate, The crop will be ready to gather in three
weeks or a month from first applying the heat, but so much
mischief ensues when this is violent, that I would advise
every one to begin time enough, and force slowly, rathei*
than quickly. It is also necessary to cut the leaves off a foi-t-
night or three weeks before they decay, from such plants as
you intend to force very early.

VL

On Grease, and some Medicinal Compounds, of which it is
the Basis: by H. A. Vogkl, Chemical Operator in the
Pharmaceutic School at Paris, Abridged bi/ Bouillon-
Lagrange*.

R. Vogel, not having an opportunity of instituting a Lard.
comparative examination of the soit fat of various animals,
confined himself to hog's lard, the most common, and of
most extensive use.

Lurd, exposed for two months to the rays of the sun, Effects of lii^ht
without access of air, acquires a very pungent rancid smell, ^" ^*"
an acrid taste that affects the throat a long time, and a yel-
loAv colour, but no acidity. By the, joint action of light Of atr.
and air the same phenomena take place, and in addition it
becomes acid. .

It melts at 104° or 108® F,, and remains in fusion at this Ofciiloiic.
temperature without being decomposed ; but above '21^2^ der
compos ton commences. If it iiave been well washed, it
allords no traces of ammonia on distillation.

Mixed With half its weiLiht of washed flowers of sulphur, Dissolves sul-
forrajng what is commonly called sulphur pomatum, and P^^ur.
examined four days after, as well as when kept much longer,
no trace of sulphuric acid vtas discoverable. By gentle fu»

* Abridged from the Annates de Chiniie, Vol. LVIII, p. 154, May,
1800.

sion

106 *^N LARD, AND COMPOUNDS MADE WITH IT.

bion on a water bath a portion of the lard was separated,

and poured off; and by straining the rest through tine linen

the greater part was obtained. It was of a gray colour, aud

a very strong, acrid, bitter taste ; stood more readily on

cooling; and blackened silver. If sulphuretted lard be

boiled, decanted, and cooled quickly, part of the sulphur

precipitates: but if it be cooled slowly it crystallizes in line

needles.

This com- If this mixture be distilled in a coated glass retort, to

pound ^^*^j^^^_ which a receiver is adapted communicating with a mercurial

etted and car- trough, a large quantity of gas is obtained, which appears

buretted hidro- 1.^ |jg j^ mixture of a £>reat deal of sulphuretted hidroj>en,

gen&carbcmc . , ,., , ,. , , • i ivx

^cid: some carburetted nidrogen, and a little carbonic acid. ISo

sulphurous acid gas was found, as many chemists assert.

lard mixed As soon as the gusses cease to come over, thick, white va-

w.th sulphur pours rise, that condense with difficulty, and a yellow mat-
subhmesj * . . - , "...

ter sublimes into the neck of the retort, which is lard mixed

with a litiie sulphur. The liquor in the receiver is milky,

and on cooling ailbrds small crystals in white scales, which

a bulky coal are Bulphur in a state of extreme division. A very bulky,

remains i^hining, iiidiiscent coal i*eiiui".ns in the retort.

Sulphuretted Sulphuretted hidrogen gas, passed through melted lard,

hidrogen not p,.(^fiu(.es no chan;2re, and does not dissolve in it.

dissolved in it. '^^ ,

Dissolves a lit- Half an ounce of lard being melted on a water bath, two

tie phosphorus, grains of well purified and very transparent phosphorus were
added, and kept a quarter of an hour at the same tempera-
ture ; care being taken not to shake it too much, that the
air might not acidify the phosphorus. When cold, some of
the phosphorus was found undissolved. The lard Iiad ac-
quired a slight smell of garlic, and a disagreeable taste : it
reddened infusion of litmus: it formed a very copious black
precipitate with nitrate of silver, and a less abundant black
precipitate with neutral nitrate of mercury at a minimum.
An ounce of lard, brought to boil gently, was found to
dissolve five grains of phosphorus; but part was precipitated
by cooling. The lard was repeatedly washed with boihng
water, which it rendered acrid; but it still retained some
of the phosjUiorus in actual solution, without its being acid-
, ined.

The

ON LARD, AND COMPOUNDS MADE WITH IT. . IQJ

The phosphu retted lard prepa-ed with a boillui^ or a Sjen- Faintly lumi-
tle hear, and wa .bed or unwashed, did not shine in tl)e durk j)°^'j|.^^ ^^
at a teni erutuie ot 55° or Oj-', even when rubbed by the
haiid. At lt)7° it was fainti}^ luminous.

Twelve grains of phosphorus bein^ distilled with two Lard distilled
oniroes of lard, the mixture assumed a coally aspect much "* poosphB
sooner than lard alone. At the commencement phosphu-
retted hid:ogen gas was evolved, which took fire in the re-
ceiver; and afterward both phosphuretted and carbnretted
hidrogen were oi)tained in a jar over mercury. The receiver
contained lard, whit h had carried over with it phosphorus
and [jhosphu retted hidro^en gas. After cooling, on the ad-
mission of air, it burned the lard rapidly.

Whatever temperature be employed therefore, to dlssoive Phospborota*
phosphorus in laid, more or less pbos;)horous acid is always j^^^'' ^i^^ay*
formed ; whence I am induced to think, that the same thing
happens in many other phosphuretted compounds.

AH these experiments were made in contact with air. Tf air v ere ex-
When air was exciudvd, the lard dissolved a portion of phos- eluded, it soon
phorus without its being aciditied ; but it became acid in a on expoiu/e to
few minutes, on pouring out the nieited lard, or shaking it it-
in the open air.

A cylinder 10 inches long and 8 lines in diameter was fill- -VsMe^ phas-
ed with melted laid, and inunersed in merourj^ Half of it phorus from
being expelled in this situation by phosphuretted hidrogen hidro .;u.
gas, the cylinder was corked, removed into hot water to keep
the lard in fusion, and shaken tiil co.d. On examination it
was found to have diaaoived all ti;e piio-ipiiorus contained m
the gas.

As the muriatic acid does not act on hud, and t!-.er& is no- Action of
thing interesting in the action of the sulphuric, l\ir. Vogtl acids.
contined himself to tije nitric. He treated lard with it as
directed by Fourcioy and Alyon ibr making the oxigenized
pomatum. Alyon observes, that this pomatum has no need
of being washed^ as it is not acid. Vogel iepeated his pro- ^'jtric always
cess with an ounce of acid at 3ii^ to a paund of iard ; ana 'eaves It acid,
afterward with acid at 30^ 28^, and as weak as 24*^ ; but he
alwavs found the oxigen'.Eed lard acid.

Making the experiment in a retort communicating with a Nitrogen, ni-
pneuinato-cheanical apparatus, he obtained niti'Ogeu gas, n(»t t^ous, aud car*

pure,

JQg ON LARD, ABD COMPOUNDS MADE WITH IT,

botiic acH ^as- pure, as Mr. Alyoii says, but mixed with nitrous gas and
ses eYolved. carbonic acid gas, as Van Mens foiuKj.

Lardoxigen- The hird thus oxigenized is as hard us suet, and requires
ized by nitric ^ heat of 113° or 1 17x° to raelt it. Water boded with it,
and partly evaporated, acquired a lejnon colour, and a rough,
bitter taste ; reddened litmus ; and constantly precipitated
acetate of lead and nitrate of mercury. Distill^ in a retort
almost to dryness it yields a colourless fluitf containing a
qnantity of acetic acid, and not precipitating the metallic
solutions above mentioned.
YicMsan acid The water in which it is washed, bejng evaporated to the
owaer. f^onsistence of a thick liquid, lets full on cooling a brown,

tenacious matter, attracting moisture from the air. The
supernatant liquor bei no- decanted and evaporated, an infi-
iiite number of small, white, very bnliiant needles form in
it. These Mr. Vogel took at first for oxalic acid, but lime-
water was not rendered turbid by it, and it had none of the
properties of oxalic acid. Its nature will be st-eu below.
K<rthcrtheco- Neither tlie yellow colour nor acidity of oxigenized lard
JTmclv^e'dby'^'^ can be removed by repeated ablutrons ; for after the twelfth
vasbing, boiling it continues yellow, and tlie wat^r poured off from it

reddens litmus.
Alcohol dis- Alcohol comports itself differently. If it be boiled with

solves a large QxiLjenized lard, it dissolves a very lav-^e quantity ; and on
cooling a great dtnil separates in flocks, which, collected
and dried, afford an oxigenized lard strikingly whitened.
The remaining lard is rendered whiter: the alcohol acquires
a yellow colour, and becomes acid ; and it retains matter
enough in solution to fo^rn a copious prt^cipitate with water.

whic^i is after- q['}^P alcohol being evaporated, a great deal of yellow acid
-ward partly so- _ . , ,/- , i ii • i.

liible in witer. ^^^ remamcd, winch was partly soluble in water.

Does not re- Boiling alcohol however, employed repeatedly to wash

moves its acid- oxigenized lard, does not deprive it completely of acidity: it

* ^* rather dissolves the greater part of it, and the last liquor is

still acid.

The acidsepa- ^^ ^^^^ '^^'^^ adheres so intimately to the lard, T attempted

rated by lime : to se])arate it by salifiable bases. For this purpose I boiled

it with lime water, which was thus deprived of its alkalinity,

and ac(|uired a lemon colour. This neutral liquor, which I

* considered as a compound of lime with an acid and lard,

wa>>

ON LARD, AND COMPOUNDS MADE WITH IT. 1 Qg

was copiously preclpitatecl by acetate of lead. Evaporated
to the conslbteijce oi'a sirup, it was divested of colour by the
nitric and muriatic acids> which formed in it a whitish pre-
cipitate ; iuid on pouring in the acid a very rancid smell was
perceived. , -

Barytes water acts on the oxigenized lard more effectually, and more effcjc-
Theoranj^e yellow colour it acquires from it is equally de- ^"^^*y "7 °^''
stroyed by acids. I poured in a quantity of sulphuric acid
sufficient to take up the barytes, boiled the whole, and fil-
tered it at a boiling heat. The filtered liquor, which con-
tained nT> barytes, was evaporated in great part on a sand
heat. Small slender needles crystallized from it, inter-
spersed with silkv tufts. These were insoluble in alcohol,
did not precipitate lime water, and were not sublimable in
close vessels.

- If lard be boiled in concentrated nitric acid, and the ebul- Bailing niirjc
lition be continued, addinp^ water occasionally, a crystalline verulenrcfr"
White powder forms in it on cooling. This powder is rough tals,
'to the touch, insoluble in alcohol, and much more soluble in
hot water than in cold. Uy its combinations with diflerent which are' sac-
bases, and other characters, I satistied myself, that it was ^^^'^^^'^^'c acid.
tnucous acid*.

Lard thus oxigenized at a maxii;!;iiim is soft, of a brown L^^j-d oxi«^eii-
colour, perceptibly soluble in water, and vejy soluble in al- i-'^d at a maxi
cohol. The water in which it was washed being saturated "^""^'
by potash, the result was a foliated salt, attracting humidity Affords acetic
from the air, and giving out acetic acid mi treating it with '^^^''^'
sulphuric f. The precipitate ibrmed by acetate of lead in
this water is nothing but the lard itself, which combines
with the oxide of" lead, and carries down with it a little mu-
cous acid. The former swims on the surlace, when the pre-
cipitate is decomposed by sulphuric acid. . "

Oxigetrlzed lard being very soluble in alcohol, a large
quantity may be precipitated from it by water. By the
powerful action of concentrated nitric acid on lard a certain Nitrate of ani*
quantity of nitrate. of ammonia is forujed,; as may be seen "^<^^»^ ^o'^*^-

* Beef, suet, though, it decomposes ftitrie -acid less powerfully, like-
wise affoids mucous aCid.

f Rancid fat and'very" old suet likewise afforded Mr. Vogel acetic acid,
when treated in the same mauner. * •

by

110 OS T.ARB, AND COMPOUNDS MADE WITH IT.

by boiling down the water in which it is washed, and addinj?

to it potasli or quick lime.

Action of oxi- ^he action of oxigenized mmiatic acid not Itavinj^ yet

Stic acid. been described, Mr. Vo^el conceived it mi^ht be nst fVil to

enter into -t somewhat at large. He passed a lartjre quantity of

the acid in the state of gas through Utrd ke[>t in fusion on a

water bath. The gas previously travc-vsed a phial containing

water, and the process was continued, t;ll the bubbles were

no longer detained in the lard, which absorbed a very large

quantity. When cold, the lard was considerably increased

in wc'vt^ht, of a dirty white colour, and ranch aUered ia its

consistence ; as it was soft, resembling a thick oilv fluM, so

as to be capable of being poured easilv f-om one hot 'te into

another, at a temperature of 55°. When first exposed to

the air it emitted white acid vapours.

After standing exposed to the air for two months, it ac*

quired a little more solidity, but never that of common lard,

ttg taste was rancid, not perceptibly acid, and left behind it

Very little of a slight bitterness imtuting the throat. The simple muria-*

the acid taken ^^^ ^^-^ ^,^g g^ combined with the lard, that only a very
up by water, . ' . *

t>ut expelled small portion could be taken up by washing with boiling

by the nitric, water. Nitric acid however expelled it abundantly in the
Tvhich does not form of white vapours with effervescence: yet, what is sin-
fore, g"^*^'* the nitric acid is not decomposed, in whatever quan-
tity it be employed, and the lard acquires neither colour nor
solidity from it.
Actions on It is known, that fat acts more or less on several metals,
jncials. Copper for instance gives it a green colour, when air can act

jointly with it.
Mercury. As the combination of mercury with it is of most import-

ance to the art of pharmacy, Mr. Vogel attended to this
tnore particularly. Many apothecaries have endeavoured to
improve the processes for medicines of this kind, ^nd parti-
cularly for the strong mercurial ointiuent. Mr. Veau De-
launay proposes rancid oib and Fourcroy has shown, that
fat when oxigenized is better adapted for the extinction of
mercury. Many chenusts have suspected, that the mercury
in this ointment is in the metallic state, and not oxided*
Mr. Vogel, knowing no experiment to support this opinion,
made the following.

He

ON LARD, AND COMPOUNDS MADE WITH IT, 1 M

He triturated equal parts of lard and mercury in a mor- Gains no oxi-
lar, which he had accurately weighed. When the mercury arrlntrituraUoa
was completely extinguished, he weighed the mortar with with iard.
the ointment in it, and found it had gained nothing. Hence
he inferred, that the mercury, if oxided, must have been
so at the expense of the lard, and not by the oxigen of the
air.

To discover the state of the mercury, he introduced this It remains ia
ointment recently prepared into a cylinder of glass hermeti- g^^^^^
cally sealed at one end ; and kept it three hours in boiling
water. After it was cold two very distinct strata appeared,
the uppermost of which was white like lard. From this he
separated the lower by cutting the cylinder with a file. On
braying this gently with hot water, 3 drachms 3 grs. of
running mercury were collected. Tlie remainder, which
obstinately retained a little lard, was treated with a lie of
caustic potash. The soap formed was dissolved in alcohol,
and thus the whole of the mercury was recovered.

He likewise separated the lard from the mercury by boil- Farther proof*
ing the ointment in water. The lard swam on the top, o^^^i*'
slightly coloured by a little mercury, that adhered strongly
to it: and the mercury remained at the bottom of the vessel,
mixed with a little lard, but the slightest agitation united its
globules.

The ointment being treated with muriatic acid in close
vessels, no oxigenized muriatic gas was evolved.

Ointments that had been prepared three months, eiglit The mercury

months, and several years, beiny^ examined, a little oxided acquires a I ittl«
„ , , , -n • 1 oxigen by long

mercury was found, but the greater part was still m the me- keeping.

tallic state.

Mr. Vogel likewise triturated mercury with Venice tur- Mercury not
pentine, which extinguished it with facility. The turpentine ^'^^"^^ ^y **""*
being then dissolved in alcohol, the mercury was left behind
in little globules ; and the alcohol being evaporated, the
turpentine was recovered without any alteration in its pro-
perties.

In these ointments, therefore, the mercury is not in the Merely divided
state of oxide, as has generally been supposed, but merely '" t|jese and
divided very minutely. Mr. Vogel is likewise inclined to pounds,
think, that it is in a similar state iij many mercurial com-
pounds

l\Q ON LARD, AND COMPOUNDS MADE WITH IT.

pounds more or less in use, as the mercurial piaster of Vigo,
ethiops saccharatiis, ethiops alkalisatus, Plenck's gummy
mercurial, aud a number of s'.milar mixtures. If the colour
be objected, it may be observed, that antimony, however
brilliant, bismuth, or any other metal capiible of being pow-
dered, becomes of a blackish gray when minutely divided.
Action on salfs. Mr. Vo^el next examined the action of fat on metallic

salts.

Ointment of He prepared the unguentum citrhmm by dissolving three

Hlve^r.^^^"*^^' ounces of mercury in four of uitric acid, and mixing them

with two pounds of lard. As the surface of this ointment

always grows white after a time, for wliieh some account by

ascribing it gratuitously to the absopption of oxigeu by the

air, he poured this ointment while still fluid into squares of

paper. Some of these he' placed under a jar filled with air

over mercury. Tn twenty-four, hours no absorption had

taken place, yet the surface was strikingly whitened. Others

he placed under the receiver of an airpump, in which he

speedily made a vacuum ; and. this he kept up for some

hours, giving occasionally a stroke with the p'ston, which at

lirst occasioned an ebullition of air-bubbles. The ointment

. when removed from the vacuum was perfectly yellow, and

remained in this state without the least change.

Whiteness of From these experiments he conceives, that the white crust

the surface ow- jg owing" to the extrication of gas, either nitrogen or nitrous,

ing to air (le- .... „ ,, i • i ^ ^ i /• ' ■ ■,

taineJ there, which arrives rrom all the internal parts at the surtace, and

increases its volume. As it gradually cools, it does not l^ave

the gas time to escape entirely, so that part of it remains,

and forms an infiuite number of small white bubbles at the

surface. ' . i*^

Mavbemade i^^ confirmation of this may be added,- that, when the

so as to remain ointment is suiiered to cool in the vessel in which it was kept

^ ' in fusion, and |5articularly when it is still heated a little,

the quantity of caloric is sufficient to expel all the gas, and

the ointment remai^ns constantly yellow, without undergoing

any farther alteration..

„ ., ■ To examine this compound, and form a judgment of the

Boilca in wa- jo

ttr. chemical changes, that might have taken place, Mr. Vogel

bojled in water for half an hour some ointment, that had

been made about two years* It became very clotty, and the

water

ON LARD, AND COMPOUNDS MADE WITH IT. I ^5

water was so interposed, that it was difficult to separate the
whole of it. The water acquired a yellow colour, and a
slii^Htly bitter taste; was scarcely at all acid; aud did not
coutaiii an atom of mercviry.

By wny of comparison some ointment only a day old was
treated with hot water as loni* as it would take up any thing.
This had nearly the same clinvacters as the water with which
the old ointment was washed, and scarcely exhibited any
traces of mercury on the addition of a hidrosulphuret.

Henco ii was natural to conclude, that the acid nitrate of The acid con.
mercury had undergone a change; aud it might be P^^" curv to vdlow
8umed, that it had passed to the state of yellow nitrate, or nitrate.
nitrous turbith, which is little soluble in water. On keep-
ing the ointment a long time in fusion, liowever, no turbith
separated f o n it, so that it must be intimately united or
dissolved in the la^-d. To satisfy himself of the possibility Oxlgenized
of this solution, Mr. Vogel heated turbith with oxigenized la'dandydlow
Jard; and having decanted the clear fluid part, it perfectly form unguen-
resembled the unguentum citriuum, and contained a large turn citrmuro.
quantity of mercury.

With respect to the virtues of this ointment, which some Some consider

physiciansi assert are the same with those of lard simply oxi- the mercury as
. ... ... useless.

genized by nitric acid, I do not pretend to decide : but it is

probable, that a substance containing mercury in actual

combination must produce different effects from one that

does ijot.

Instead of the acid nitmte employed above, Mr. Vogel Neutral nitrate

next took neutral nitrate at a minimum, reduced it to a fine ^^'^"ffs^ from

■ white to vel-

powder, and projected it into heated lard. Bubliles were low by lard;

immediately produced, and the white powder of the nitrate

was soon changed to a yellow. The lard acquired a solid

consistence, and contained mercury in solution.

The neutral nitrate then is decomposed by lard : not that which takes up
the mercur>' parts with oxigen to it, for it is already at a mi- part of its acid.
nimufii ; but the nitric acid quits in part the oxide of mer-
cury, and attacks the lard, by which it is decomposed ; the
result of which is yellow nitrate of mercury, whjch in fact
contains but little nitric acid.

With the njtrates of silver and lead, and the oximuriates Other mct»lli«
of platina and mercury, very little decompositioi^ takes place, **^^*'

Yoi^-XVlU-OwT. I8O7. . I ' and

114 FORMATION OF FLINT,

and they 60 not produce the same effects oh lard as the ni-
trates of mercury,
©enerai ccn- From the facts here adduced we may infer,
elusions. i^ That light, without air, turns lard yellow, and gives it

an acrid, rancid taste, without acidifying it.

2. That lard yields no ammonia by distillation, and con-
tains no nitrogen, so that it may be considered as a purely
vegetable substance.

3. That in the sulphur pomatum a portion of sulphur is
dissolved, without being acidified.

4. That phosphorus dissolves in it, but is quickly changed
into phosphorous acid, and its acidification is increased by
the contact of air.

5. That lavd oxigenized by long exposure to air constant-^
ly becomes acid. That the water with which it is washed
precipitates some metallic solutions, and, if distilled, gives
oi^t at last acetic acid. ■

C. That nitric acid forms with lard a yellow bitter sub^
tance, acetic acid and mucous acid. That the latter can-
not be completely separated from it by washing ; and that
it is equally obtainable from suet by means of nitric acid,

7. That the oxigenized muriatic acid is decomposed by
lard, which it leaves whitish, very soft, and incapable of fur-
nishing the yellow bitter matter, when subsequently treated

<. with nitric acid.

8. That mercury is in the metallic state, but very minute*
ly divided, in fresh prepared mercurial ointment.

9. 1 hat in the unguentum citrinum the mercury is a ni-
trate with oxide at a minimum : that the white appearance
of the surface is owing to bubbles of gas: and that the neu-
tral nitrate ot" niercury at a minimum is decomposed in lard,

VII.

Extract of a Memoir of Mr, HaqueTj on the Formation of
Flint*.

Flint of recent "^ ^^^^ the vai'ions proofs, which this gentleman has
forniation. adduced of the recent formation of flint, we shall cite the
following.

* Journal (i§s Mines, No. 119, p. 405. November, t806.

In

OXIDATION OF LEAD SOLDER. 1 ] §

In the chalks of Volhynia there are a great number of , ^-

flints, in the form of nodules more or less large. In on^ Petrified woo4^
place were found two as big as a man's fist, enclosing petri* **"" *^ * *
fied roots of wood. The autlior possesses one of these, the
wood in which has not altered in colour, and appears to be
beech. Another nodule found in the same place contains a
number of splinters of wood.

The chalk, from which these flints were taken, analysed Analysis of tb»
by Mr. Haquet, gave in 100 parts, lime 47, magnesia 8, '^^^^^^ ^^*
carbonic acid 33, silex 7, alumine 2, oxide of iron 0*5.

He has likewise analysed several flints from different
places, ^nd found them containing :

Silex ...ff 92*75 •• 92-50.. 92-75.. 97 ••89 Analysesof

Alumine I-IO-. .. 1-50.. 1 ..2 ^i^^s.

Lime 1-25.. 3 .- 2-75.. 0-25«r 4-15

Magnesia ...••• •« •. 0-51'. ••

Oxide of iron 2 • • 1*25. . 1 • » 1 • • 1'75

Oxide of manganese •• 0*75. •

Mr. Haquet observes, that flints are never found at any Always near
nsiderable depth; and the deeper we go, tli
more distant from each other are the nodules.

considerable depth; and the deeper we go, the smaller and * ^® ^"' '^^*^'

VIII.

Of the Oxidation of the Solder <if Leaden Vessels used in
Wash-houses; by J, C.X>ELA^^TiiERiE*,

xILN enlightened amateur of the arts, Mr. Fougeray de Lead solder

^Launai, who lives near Soissons, informed me, that Taun- *^ '"r^^^'* '** '.

• . . Z . "" vessels used lO

dresses, who wash geat quantities of linen, use for their washing.

b^ucklng tubs large vessels made of se\'eral sheets of lead,

soldered together with the common solder consisting of lead

and tin. This solder suffers no damage, as long as the ves-

pel is kept in use : but if it be left empty for a few months,

the >«older is so much oxided, that the lead must be soldered

afresh, before it will hold lie again. 1 requested prof, Vau-

<jueiiii to examine this solder, and the following is the result.

He found, that it consisted almost whoUy of carbonated The lead con-

• Journal de Pbysiciue, Vol.LXllI, p. 252. September, 1806.

I 2 ©xide

115 CAlCULATfON OP CHANCES, &C.

verted into a oxide of lead, with a few particles of iron and tin. From

ona e, \\^\s^ and the circumstances under whicli it appeared to have

been formed, he concluded, that the metals forming the

solder were oxided by the air throut^h the influence of the

alkali, and that at the same time the carbonate of potash

WeVand dlf-'^' ^^^ ^^^" decomposed ; that is to say, the alkali had united

solved. with the tin, and the carbonic acid with the oxide of Uad.

Oxides of tin This conjecture he verified by a direct experiment, taking

th'^ d*** ^°S®' nearly equal parts of oxide of tin and oxide of lead, and

pose carbonate heating them slightly with a solution of carbonate of potash,

of potash, 'pjje f^j^ ^as dissolved, and the lead carbonated.

VII.

J^xample of a Calculation in the Doctrine oj' Chances; a Tide
Table; and Remarks on the breaking of Waves, In a Let'^
ter from a Correspondent,

To Mr. NICHOLSON,
SIR,

Jt^ Friend of mine, who has been spending the summer ai
a watenng place, has proposed to me some questions, which
arose out of the amusements of the season, but which it re-
quired some little consideration to answer in a satisfactory
manner. If you think the results of my reflections likely
to be Interesting to your readers, they are much at your ser-
vice.
"What is the !• The first question was how to determine the chance of

chance of win- winning a raffle, when you have thrown a given number. It
a'given^num-'^ is usual to throw three times, with three dice; the highest,
ber thrown? or sometimes the lowest, wins ; and if two or more persons
throw the same number, they must raffle again among
themselves. We must first calculate the chance, that none
of the persons who are to throw will throw higher; and then
the chame, that, if they da not, any one of them will tlirow
the same number, or any two, three, or more; but as thjs
caiculati6h cannot easily be made during the time of rat-
f!ihg, I have made a table which is sufficiently accurate for
the purpose.
r:^ . A Talk

CHANCES OP WINNING A RAFPtE.

117

^

'^

^

Oi

00 r^

CTi

a>

CO

-15

s

CO
CO

• Si"

CO

CTi -^ r^ "^

o^. C^ O^. C^d

oo o -^^ cy

j>. »^< »-i CO

O^ZTi CO <X)

a X 00 i^

o o o* »o

CTj 30 b^ 'O

C CO CO CO

:x: t>- 'o 'O

-< to o* c^

»0 'O O* C')

»> O -* CO

CO t^ 0> CO ■

'O -J' CO c^

—< GO CO "*

•O CO C^ -'

^ CT) CO «0

'O '-« o o

CTi in ^ o*

CO 'H

C^ O CO '^

o a^

O^ 00

»0 CN
CC CO

00 -^

CO c-<

-* 00

'O •

c^ •
i>- »o

00 00

b t--

00 t>.

O l>-

CTj'O
lO »o

r^ ^

CO o^

CO'CN
0» 00

C< r-l

CO O
CO o»

'f • CO o?

O^ GO

OC^GON.'O^O-'tCOC^'^OO

CTioOoOGOoOoOcOOOoOOOoOt^

'*C*Oa^N.'O'i<c0.-<O'v0N.
00 GO 00 K. l^ t^ l^ t^ tN. t^ O O

»Oc>?OoO'Oco-<C^ooCO'*CO
Ir^ t>. L^ 'O sO O O lO ^ to t'i »0

<?'^Ci»^-*CNC^N-'r1<C^OCO^

O'sOtO'OtO-h'^'j^'^ri'COCO

Ot^HiOcC'OCNOcCtO'^'^^
tO^ri^ri^cOCOCOGOC^O^CJC'

"^ "* O i^ -^^ c-/

CO CO CO C< CN C9

C 00 'O ■>* 0*5 C^

<N •-* rH — - >-<

-* - CC
0» O* r^

»0 CO -^,Q 00 t^'O <i •*

•*c<C?ib>.0»^'*coo?« •>-•
t>-5O'*c0 0>»'-t» • • • •
C0C<».-1««»«»«*»

CO 'O ^ c^

w> o

0< CO ">+ 'O 'O t-* 3C O^ O

*o

o

»

CN

-*

t>»

.—

CN

CO

'O

t>^

.^^

^

CO

o

o*

^

1—

r»

c-

^^-^

c

,.j rr 'O ^

:::::::: §S :

S?: : : :

cO • ♦ -« •

:g: :g

ac 00

** 2

C< r-t O
{>. t^ t-

00 t>.'0 lO -^ CO
t>. t> 1^ t>. H. b.

'OrfcOC^-^C^cOb^'sOiO

'O 'O ^ 'O 'O to to »^ <o »o

'^O^N.^**coC*OOiOO
tO'*««t-^'^-n*-<i'-<?coco

-^CO-'OoOt^'O-'tCOO*
C0CO50C0C-JC»C^C>»O«C^

O -f CO c<» -< o
O ^00 • I>.<0 lO • "f •

.-'0<c0"+'O^Ot>.00C?iO

«}/> fee S .*,

G a <v ^
*c '5 '^ 2

*> ^ x; *"

s^^ §

•c o ■£ °*

rt — I 4>

? ^ c *
- *« 2
«4- o ^ jr
o«^ « -

4) <« ^ V

C *bD O ««
rt B "^ •-»

I ?^ -*

C O « *J

t 13 TIDE TABLE, &C.

Universal tide 2. In the secotid place I was abked for the easiest mode of
^' fiiiding the time of high wqter, with sufficient accuracy for

common purposes. I have made a table, which, I believe,
. is- tolerably correct; but not being so conversant in the sub-
ject as I could wish, 1 shoiild be much obliged to any of
your correspondents skilled in navigation, if they would
compare it with the best observations, and inform me whe-
ther they approve of the principle.
Waves break 3. Xhe third inquiry related to the cause of the breaking
the lip )er part ^^ a wave into surf. Waves seldom break at sea, unless
moving fa-'.er the wind is very high : but when they approach the shore,
e ower, ^^^^^ always break sooner or later. The general reason of
their breaking appears to be the excess of the velocity with
which the upper part of the wave advances above that of the
lower part: and this may be derived either from the effect of
the wind on the upper part, or from the resistance of the
bottom to the motion of the lower part, or from a third
cause, which is more general, where the magnitude of the
wave is at all considerable in comparison with the depth of
the fluid; for in this case the upper part of the wave must
have a natural tendency to advance more rapidly than the
lower, on account of the greater depth which determines its
velocity. Beside this, the form of the wave itself, where
the water is shallow, may be such as to render it incapable
of advancing without a change of the direction of its ante-
rior surface into a situation more nearly vertical,
Defect in the ^^ *^^ calculations by which the velocity of waves has
calculation of been determined, it has been usual to neglect not only the
wlfvw!'''''^^ ^"^ difference of the whole depth of the fluid at different parts
of the wavers surface, but also the immediate effect of the
w horizontal motion of the particles, so far as it is not con-

cerned in producing an elevation or depression by its varia-
. tions. The theory, abstracted from these considerations, is
^ perfectly correct ; and may be combined with their results

so as to be rendered applicable to some cases, which are not
otherwise comprehended by it. Thus if we suppose a wave,
terminated by two planes, equally inclined, to be placed in
a surface on which it can move without resistance, it may be
shown, that the highest point will begin to be flattened with
the velocity deducible from the depth at that point, the new

angular

BREAKING OF WAVES. J 19

anovular point advancing on each side upon the inclined sur*
face with a velocity which is at tirst equal to that which is
due to half the depth, and is afterwards uniformly retarded;
so that the angle is twice as long- in travelling- over the whole
surface of the wave, as it would otherw ise have been. The
centre descends at first more rapidly than the part nearer
the margin, so that the wave becomes concave in the mid-
dle, instead of being flat, as it would be if the depth of the
fluid were very great. In the mean time the margins of the
wave advance with a velocity, which continues to be um«
formly accelerated, until the angle reaches it; and this ve-
locity is as much smaller than that of a body falling by its
weight, as the height of the wave is smaller than half the
breadth : for the whole horizontal pressure acting on any
vertical section of tlie wave is every where proportional to
the quantity of ttie fluid beyond it, and as long as the deeper
parts retain their form, they will urge forward the shallower
with a constant force. But if any part of the surface of the
wave be concave, the velocity thus produced in its upper
parts will cause them to advance more rapidly than the
lower, and the surface will become more and more inclined
to the horizon: if on the contrary it be convex, the lower
parts will be protruded, and the convexity will be diminish-
ed. Beside the case of a wave advancing in consequence These reason-
of its gravitation on a flat shore, these considerations aie Jq^'^Jq^^q^qji
also applicable to that of a drop of oil, spreading, by the spreading on
force of cohesion, on the surface of a vessel of water. ^* ^^'

I am. Sir,

Your very obedient servant,
W Sept. 1807. HYDROPHILUS.

ANNOTATION,

MY correspondent not having gone at large into the usfe'
and application of the tide table annexed, Plate IV, a little
more particular detail on the subject will probably be ac-
ceptable to many of my readers. The small shaded circle Manner of fit-
in fig. 1 being cut out, a damp wafer is to be put in its u^ng Jte^iide
place, and over it fig. 2; which is likewise to be cut out, table,

and

120 TIDB TABtR.

»n<i so adjuste<5, that its dotted circle shall coincide with that
of thp same size in fig. 1. Underneath the waier a circular
piece of paper, about the same diameter as fi^;, 2, i» to be
placed, so that fig. 2, may move f.eely rouixd on its centre.
The oblong shaded spare in fig. 2 is to be cut out previously,
so that the name of the place, for which we want to find thfe
time of highwater, may appear through it. The table being-
thus put together, we have only to turn round tlie smaller cir-
cle, fig. 2, till the name of the place, for which we would know
the time of highwater, is seen through the aperture; when
the time for any given day will be s own by the part of the
hour-circle, fig, 2, that stands against the line of the moon's
age on that day. Thus for example, if 1 want to adjust
the table to Worthing, having turned the circle till Worth-
' ing appears through it, I shall find, that, when the moon
is two days old, it will be high water there about five mi-
nutes before 12 ; when the moon is nine days old, about a
quarter after 6 ; and so for any other day.

The difference of the length of the lines in the larger
circle points out the progressive increase and decrease of the
rise of the tide ; showing its comparative height, from the
spring tide, when it is the greate&t, being about 36 hour*
after new or full moon, at every place, to the neap, when it
is the least. Hence, if we know what is the general rise of
the spring tides at any place, we may calculate how high
the tide may be expected to flow at any given time of the
moon's age.
Table to show As it is obviously essential for finding the time of high
themoon'sage. ^ater to know the moon's age, a general table of lunations
is annexed. The use of it being sufficiently explained in
the table itself, all that is necessary for me to say is, that
the small shaded circle of fig. 4 is to be cut out, and fig. 3
to be cut out and put over it in the same manner as fig. 2
over fig. 1.

For the gratification of such of my readers as might wish
to have these tables in a form for use, without taking the
trouble of copying them, or destroying the plate, I have
given a duplicate of it, which may be cut out and pasted on
a card.

Hydrophilus will no doubt perceive, that! have taken the

libert/

U/ui^'Da/f ^^^-^ ' /al^y

, A^iv/^nJ /M<»^^fHWmd^Vbl.miLrL.IV.pA2o.

BRiTTStI ENCRINITES. 121

liberty of making a slight alteration in the title of one of
his tables. If the reason of this -iiouhl not readily suggest
itself to him, it will be explained iri a private letter, oti^ his
favouring me with his address.

X.

Nondescript Encrinus, in Mr, Donovan's Museum*

SIR,

Jl ERMIT me through your excellent -publication, to ac- Mr. Donovan'i
knowledge ray obligations to Mr. Donovan, for the advan- Museum,
tages I have derived in my inquiries respecting the mineral-
ized remains of the animals of the former world, from the
examination of the inestimable fossils, contained in his
matchless museum.

By the investigations which I had previously made, and Several species

from specimens in my own collection, I had ascertained, o^ ^"<^""^*^^

-.^ , 1 , -,11 , • n ' • found inEng-

tnat tiUgland alone yielded several species ot encrimtes; as land.

I trust I shall show in the second volume of Organic Re-
mains of the former World, now in the press. But by an
examination of the series of fossils in this department of the
London Museum as above mentioned, I have gained the
knowledge, that our own country can boast of yielding at
least one additional curious species of this animal, hitherto New species.
I believe unknown ; and forming by the length of the arms
an intermediate species between the lily and plumose encri-
nus. The specimen of which I speak is numbered 924 in
the brief catalogue which is delivered at the museum.

From another specimen in the same collection, marked Tortoise encri-
950, I also acknowledge having derived ver}'^ considerable
information respecting the structure of that wonderful lost
animal, the tortoise encrinus.

Having no reason for concealing any of the motives which
induce me to trouble you with this request, I do not hesi-
tate to avow, that one of these is a wish to call the attention
of the curious, as well as scientific, to the most complete
collection of British Natural History, which has ever yet

been

nus.

132 IRRANGI^MENT OP THE SEDtMGKT OP WATER.

fccea furmed ; a museum not confined to any one particular
branch, but comprehending alike the three great depart-
ments of nature, the zoological, botanical, and mineral
productions of the island, upon the grandest scale possible.
It will not be too much to say, that this museum, from the
science evinced in its arrangement, independent of its im-
portance as a collection of choice and valuable specimens,
must, to those desirous of such knowledge, prove a most
instructive school ; and afford an inexhaustible fund of In-
formation to all those, who think the Natural Flistory of their
own country worth attending to,
1 am, SIR,

Your most obedient servant,
Mr. Nicholson. JAMES PARKINSON,

SepU Gth, 1807. Hoxtiyji Square,

Author of *' Organic Remains,'*
** Memoranda Chemica,'* &c.

XI.

Inquiry respecting a Fact not hitherto noticed in the way of
discussion^ In a Letter from R. B.

To. Mr. NICHOLSON.
SIR,

Sediment of V V HEN turbid water has become clear by subsidence,

water thrown ^^ light stratum of earthy matter, which covers the bottom
jato undula- ° . •^ i • • i

tion arranges of the vessel, is often, as might be expected, distributed

rr' yr ^^^^^' without any particular appearance of, symmetry : but if
the vessel be slightly moved liorizontally, so as to produce
an undulation of the fluid, without much disturbing the
deposit, this matter is found to arrange itself in a num-
ber of parallel ridges or embankments; or at least to indi-
cate a manifest tendency to form such ridges. I tind a

Whj? great difficulty in accounting for this fact. It seems to

suppose alternate differences in the velocity of the water,
as it runs over the bottom. These, however, seem incom-
patible with the almost .total want of elasticity in water.

Perhaps

ON THE ELECTRIC SPARtf. l^JJ

J'erliaps the hypothesis of a number of small eddies, or
rolling cylinders of water, may account for it, as ihe ridges
are at right angles to the course of the undulation. In this
supposition, however, there appears too much of gratuitous
demand. — Have the goodness to propose the matter to the
consideration of your con-espondents, if you should think
a§ I do, that no fact can be too trifling for philosophical dis-
cussion. I am, SIR,

Your obliged reader,

R. B.

XII.

Questions on some Appearances of the Electric Spark : hy 0
Correspondent,
SIR,

X Wish to be informed if it was ever remarked, that, when Question rc-

an electrical spark is taken from the conductor of a ma- specimg van-

.... ous appear-

chine, the line of white light is interrupted, and the spark auces of the
becomes red. Sometimes it assumes the form of two cones, electric spaxk.
one preceding from the conductor, and the other from the
body which is applied to it : at other times the interruption
is next the conductor ; and again it will be perceived near-
est the body receiving the spark.' When the spark is taken
at the least distance possible, the light is sometimes red,
sometimes white ; and when the spark is some inches in
length, the interruption is perceived in two or three places
of the line of white light. Any explanation of these phe-
nomena will much oblige, SIR,

Your humble servant,

TYRO.

XIII.
Extract of a Letter from Mr, BioT to Mr. Berthollet*,
Tarragona, 20tk December, 1S06,

•3l Have had an opportunity of conversing with that excel-
lent observer, Mr. de Marty, on several subjects of experi-

* Annales de Chimie, Vol.' LXI, p. 271, March, 1807.

ments

124 ^^ I^HE ABSOftPTION OF OASSES BY WATER.

tnents in which he has long been envfa^ed ; and I have re-
quested his permission to communicate to you the results,
perguaded that you will consider them extremely interest-
ing.
Influence of The experiments of which I speak have for their object
nShms ?he'" ^'^ *^^^ ^""^^ P^*^^ ^^^ influence of time on the exercise of che-
eiasicity of mical actions, when these actions tend to deprive an elastic
fluids. flui^j of its elasticity.

Oxigen gasab 1. Into a flint s^iass phial, the stopple of which was ground
ter. ^ ^ ^'^* ^'^*^ emery, and litted perfectly tight, Mr. de Marty intro-
duced a certain v]uantity of oxigen gas, and a certain quan-
titj^ of rain water, boiled or unboiled. Supposing there is
but a small quantity of water, on shaking the bottle for a
few minutes' a certain portion of the gas will be absorbed, as
may be found by opening it under water. After it has been
thus shaken and opened several times, the water in the phial
will be saturated, and absorb no more.
Left standing When things are in this state stop the bottle close, and
vessel' m^ore^*^ put it away in a place shaded from the sun, observing at the
will be absorb- same time the state of the barometer and thermometer.
*'*• After it has stood thus two or three days, shake the bottle

again, open it under water, and you will find the water rise
into it a little. Stop the bottle, put it into its place, and
shake it in the same manner from time to time. You will
always find a fresh quantity of gas absorbed, and the eflf'ect
will be the more perceptible, the longer you leave the phial
before you make the experiment.
In 18 months I niyself was witness to these eFects. Mr. de Marty had
^f^^J*^^ ^"''^ the civility, to open under water before me a phial, that had
absorbed. been kept stopped for more than a year and half, and which

contained oxigen gas with a small quantity of water. The
water rose in it very perceptibly, and the absorption appear-
ed to me e'jual at least to half the quantity of the water,
that the bottle contained before it was opened. The baro-
meter and thermometer were both nearly at the same height
as when the bottle had been set by, and the water in the
trough was at the same tempemture.
At first the gus From this expenment it appears, that the same volume
combiiies lee- ^f water, which at first was able to absorb only a certain
portion of oxigen, absorbed by the assistancsof time a more

considerable

ON THE ABSORPTION OF GASSE8 BY WATER, JjSlS

-considerable quantity. Hence it would seem, that in the
first case the air was but feebly combined, and in some sort
interposed between the particles of water: but the continued but its elastid-
action of the liquid, diminishing,' the elasticity of the gas the'u.i'ion i"^'
more and more, and contractinij; its dimensions su^ it were by inoie iutimate,
degrees, occasioned it to enter farther within the sphere of
attraction of its particles, which rendered the water capable
of absorbing- a fresh quantity of gas.

2. The same thing takes place with regard to hidrogen Hidro^en gas
gas, and Mr. de Marty afforded me the pleasure of tritness- saiua way" but
ing this likewise. The absorption was equally great. He water absorbs
finds by his experiments, that this gas is absorbed in larger j^^g ^[^^^
<juantity and with greater promptitude than ox i gen gas. He

finds also, that the bulk of the gas absorbed is not equal to
that of the water in two years.

3. Water already loaded with oxigen is better adapted to Water loadea
absorb hidrogen, and the contrary. This is analogous to absorbrihe^^
what von Humboldt and Gay-Lussac have observed, but the other more rea-
experiment of Mr. de Marty has the advantage, like the pre- ^ ^ ^*
ceding, of having been made in close vessels.

4. The absorption is so niuch the more sensible as the wa- P'"0|)ortlonaIto
ter is more considerable, and is proportional to it. water. " '^^

.5. These effects do not take place with nitrogen gas. Af- Only a limited
ter the water has been once shaken for some time with this P"' ^ i-"" ^^ i*2otc

•1, 1 1 1 , , absorbed.

gas, it will not absorb an atom more, however long it be left

in contact with it.

6. If water loaded with nitrogen be placed in contact Water saturat-
with hidrogen or oxigen gas, it will absorb it, without part- stlinl^L^^up
ing with its hidrogen. If it have been supposed, that an hidrogen or
exchange takes place, it is because in fact a little nitros-en ^^'S*"" ? ^"^^"

^ ' n OUT ceding Its

escapes at the commencement of the absorption of the hi- pl'ice.
drogen or oxigen : but on shaking the water and the gasses
together, all the n'rtrogen, that was before interposed be-
tween the particles of the water, wiii enter into it again as
before, independent of the hidrogen or oxigen absorbed.

7» The preceding result is so true, thdt an accurate ana- Thus atmo-

Jysis of atmospheric air may tnus be made by the absorbent fpl^<^"<^airrnay
. ,. , „^ , . be analysed by

action or water alone, 1 o ettect this it is sufficient, that water.

the water be previously impregnated with nitrogen ; when it
will absorb exactly '21 hundredths of the volume of the at-
mospheric

126 ON EUDIOMETRY.

mospherkr air in contact with it, precisely as a sulphuret
would do. Mr. de Marty asserts, that water thus employed
in large quantity, to prevent the process from being too te-
jdious, IS an excellent eudiometer, and he has had recourse
to it repeatedly. If you have no nitrogen at hand, water
may be impregnated with this gas by shaking it in contact
with atmospheric air, and leaving it some time in contact
with it. By these means it absorbs all the nitrogen it can
contain, and the oxigen it takes up with it does not prevent
it from absorbing in time, according to the first experiment,
that of the air to be analysed. Mr. de Marty avails himself of
this absorbing property of water to ascertain whether oxigen
gas contain any nitrogen ; for, if it do, water saturated with
nitrogen will not absorb the whole.

8 It is long since Mr. de Marty was acquainted with many
of these facts. Some of them, particularly 6 and 7, were
known to him, when he composed his Memoir on Eudiome-
try ; but he contented hhnself with simply raentionipg the
property he had observed in nitrogen.
Docs the oxi- Does this oxigeu, continuing to be absorbed, form at
gen formal! length an acid? and if so, what acid is it? The solutiau
of this problem Mr. de Marty awaits from time and expe^
rience,
"Hie experi- With respect to the preceding experiments I shall add,
Sade^'with^ that they were all made with the greatest care, in vessels well
great care. closed ; that Mr. de Marty has repeated and varied them in a
thousand manners ; and that he appears to have observed the
most scrupulous accuracy in all. '

Mr. de Marty's I shall conclude this letter with some remarks respecting
J^^'^^J°"^"-iheMeaioironEudiometry formerly published by Mr. de
Marty, of which I have a copy before me in the Spanish Ian*
guage, in the Memoriale Liferario for 1795; and of which
there is an abstract in the Journal de Physique, year 9. In
this abstract, however, many experiments have been omit-
ted ; the connexion and detail of which were indispensably
necessary to understand the course of the author, and the
conclusions at which he arrived : so that in consequence of
this omission opinions have been ascribed to Mr. de Marty
contrary to those he held, and results the reverse of those he
bought to establish.

For

ON EUDIOMETRY. 1Q7

For instance, in your Chemkal Statics you seem to insl- Mistaken by
nuate, that Mr. de .viarty a^^cribes to sulphurcts the pro- ^t^'^JJ^^"^^* ^*
pertv of absorbing nitrogen from their nature; and von
Humboldt and Gay-Lussac in their work on Eudiometry
express this opinion still more affirmatively. This errour
arose from the abstract. Mr. de Marty says expressly in Sul>ihure!%
his paper, that a hot sulphuret acts as any otl.er liquid f^^nuJog^^
would do, that had been deprived of the quantity of nitro-
gen it is naturally capable of absorbing j and thus he ac-
counted lor tli€ variatioiis he e?cperienced on operating with
greater or smaller quantities of sulphuret.

Von Humboldt aad Gay-Lussac say too, that Mr.de Mar- Proportion d
ty fixes the propprtion of oxigen in the atmosphere to be atm^osr>her« *
between '21 and '23; and hence they draw an argument
against the method of operating with sulphurets, which in ^
4:onsequence appears to them much less accurate than the
proof by hidrogeu gas. But this uncertainty between '21
and '23 Mr. de Marty experienced ouly in h s first experi-
ments : and it was from this very variation, and a wish to
diminish its extent, that he was led to discover the eriour
occasioned by the absorption of nitrogen by the sulphuret,
when it is deprived of this gas by heat ; so that when he had
completed the improvement of his method, the results were
constantly restricted between •21 and '22.

This being once thoroughly ptoved, I do not see what As a test of it,

advantage the analysis by hidrotcen eas has over that by the '^"^'^^g^" "o^

,1 1 . '. p , . . 1 . ,. , superior loah-

enlphuret, when it is pertormed with due precaution, which quid swlphuret

should always be a matter of course. It certainly has not in requiring
the advantage of requiring less time; for by operating as less time,
Mr. de Marty does, any one who hns acquired a little habit
of making the experiment can perform this in five minutes.
It has not that of greater simplicity : for the sulphu'et re- bein«rTnoTe
quires only a graduated tube, and a ground stopple bottle ; simple,
while for the hidvogen gas at least a small eudiometer and
an electrophorus are necessary ; and what is very inconve-
nient, the latter must be kept in a state to give sparks,
which is not very easy on mountains and when travelling,
particularly if the air be loaded with moisture. Lastly I
will add, that it has not the advantage of superior accuracy: or giving a
for when it is once proved, that the sulphuret will absorb "^^^^f accurate

only

J^8 ON COLOURS OF THIN PELLICLES.

only a given quantity of nitrogen as a liquid, and tliat, if it
be taken thus saturated, it constantly skives the precise pro-
portion of 'Ql in close vessels, no objection can be brought

But objection- ajrainst its use ; while a very stroni^ oue may be urged

able, as boiled " . . , . , '

■water absorbs against the use of the electric spark, since either boiled wa-
■omeoftheox- ter is employed, and then it willabsorb a small portion of
*d *nb 1 d ^^^ oxigen very g'eedily, or the water will be saturated with
jiTcs out air. air, and then the pressure occasioned by the detonation will
always lorce out nome bu!)bles. One or other of these in-
conve ieiices appears to me unavoidable ; and the latter in
particular oiten teamed me, in the numerous experiments I
had occjisiou to inake on the analysis of gasses by the elec-
tric spark, cither with Tiienaid, or alone, on the Alps* It
is true tVe diherences hence arising, when we operate with
care, amouiit only to some thousandth parts : but it is of
thou^alidth parts we are speaking; and if there be another
process, wiiic^h gives at least equal if not supTerior accuracy,
with less trouLde, it appears to me to deserve the prefer-
ence.
Air merowded Finally, to return to the memoir of Mr. de Marty, I shall

cKnrchesand add, that he has equally tried the air contained in theatres

theaties not

deficient in ox- aod m churches, when a great concourse of persons were

igen. assembled in them, and that he constantly found the same

quantity of oxigen ; an experiment which von Humboldt and

Gay-Lussac made likewise at Paris.

xiy.

Summanj Considerntmis on the Prismatic Colours of Bodies
reduced to thin Pellicles; with an Explanation of the Co-
lours of Amiealed Steel, and those of the Peacock's Fea,-
thers. A Fragment of a Work on Colours: by C, A.
Prieur*.

Tliin substan- ^ ERTAIN extremely thin substances, the thickness of

CCS exhibit ^j^jch varies proj^ressively from one part of them to another,
prismatic CO- i ?? j • n ^ p i- cf

lour^. exhibit, as is well known, a series oi colours ot ditierent

• Annales de Cliimie, Vol. LXI, p. 154, Feb. 1807.

tintSa

ON COLOURS or THIN PEtHCLES. ISQ

tints, sometimes very -brilliiint. It is hot my intention here
to describe these, still less to dispute the particulars so ad-
mirably described by Newton. 1 shall only attempt to draw-
some conclusions respecting the origin of these colours, to
establish a comparison with those arising from absorption,
and to assign the trus cause of some phenomena hitherto
diil'ereritly explained.

The principal effects, to which it is of importance for these
purposes to call the attention, are the following.

When the light falls on very thin bodies, that exhibit the When light

.• - 1 fallo oil theses

prismatic colours :

1. At the places where tliese colours arise on the thin sub- it is partly re-
stance, each pencil of rays, or if you please the white light, transmitted'^' ^
is separated into two portions in a variable manner, and one

of these portions is reflected, while the other can issue from
the substance only bj transmission.

2. This division of the pencil varies according to a cer- This depends
tain iaw, which depends on the thickness of the body, its ^^^^l^y ^and^^*
density, and the inclination of the luminous rays, inclination to

3. Each ray in particular comports itself, as if it possessed p , ,
the singular property of having fits of easy reflection at pe- alternate fits of
riodical intervals, and fits of easv transmission at other in- easy reflection

. , 1 » * n-«i • ^"" transmis-

tervals alternating with the former. 1 hese various results sion.

are equally indisputable.

But whence can this disposition of the rays arise ? Newton Newton sup-
has considered it as inherent. in the rays themselves, not only of this inherent
in that part of their passage comprised between the two ex- in the ray itself,
treme surfaces of a body that they traverse, but throughout '^ ^"^ ^ *^^*
the whole course of these rays, from the moment they begin
to issue from a luminous body*. This is a kind of occult
cause, of which it is difficult to form a clear idea; and ac-
cordingly some distinguished philosophers have shown great
hesitation to admit it.

But Newton himself, at. the end of his work, puts us into ^^ another re^
the right road in a more bappy manner, when heasks, whe- fers it to the
ther it be not by virtue of the same principle, that the rays ifg^eflection,
are reflected and refracted by bodies, and inflected in their
ricinity f.

• Opt. lib 2, part 3, prop. 13. -f lb. lib. 3, qujest, 4.

Vol. XVIII—OcT. 1807. K It

1.50 O?* COLOUKS OF THIN PELLICLES.

It 1$ taitich to be rei^retted, that tliia great man did not
treat the subject of inflexion as extensively as he did that of
coloured rings ; or even that he did not atteiid to the devia-
tion of light in the vicinity of bodies, before he examined its
changes of direction by the action of their surfaces: as un-
questionably he would have deduced new and very valuable
consequences from it.
A great analo- In fact the greatest analogy subsists between the pheno-
fhese pheno- ^^^^ of inflexion round a minute body, and those of re-
inena. flexion or transmission by thin substances : for the coloured

Coloured fringes in one case appear to follow the same law as the co-

loure^H ^\!^p:^°' l^ured rings in the other. And if this be not very sensible
follow the with respect to the fringes adjacent to the shadow of a body
same aw. ^^ small diameter received into a dark chamber, it is more
evident in the fringes produced by the light that passes be-
tween two bodies very near together ; it is still more in the
series of coloured images formed between the plumes of a
feather, when looking at a candle through them ; and it is
very manifest likewise in the bars seen by the eye, when a
piece of linen, or a series of wires very near together, is
placed between it and the light, as in the experiments of
Mr. Rittenhouse.
Method of I have found a method of rendering this resemblance still

rendering this Ytiove conspicuous. For this purpose I employ black crape,
more obvious. ,„ , , i ,, if. i i , , i

If the eye be covered thus, and irom a dark place you look

at a light a little distant, you will perceive the light sur-
rounded by a series of very apparent rings, the colours of
which are very vivid, and of the same tints as those of the co-
louTred rings of thin plates.
Candle seen If the flame of a candle be placed in the midst of a pret-

through va- ^y abundant aqueous smoke, or so that it can be seen only
^°^^' through this smoke, the flame will appear surrounded by

perfectly analogous rings. I can imitate them likewise very
conveniently by tarnishing a glass with breathing on it, and
immediately looking at the image of a luminous body either
through it or reflected from it. Those rings, which are some-
times seen surrounding the sun or moon very closely, are
probably phenomena of the same kind.
Newton speaks On the other hand Newton speaks of undulations like

of berpentine ^Uq^q of an eel, which he suspects are produced in the rays,
undulations, x * v

when

on COLOURS OF THIN PELLICLES. 131

■when they pass very near bodies*. The formation of these,
and the necessity of their existence, I think I can render
sensible.

With this view I would call tlie attention to the very in- "^°J^/J^^'^ '"'^
teresting results of the experiments of Newton and s'Grave-
sande relative to inflexion: results so certain, that no one
certainly will attempt to question them, but which it is not-
Avithstanding satisfactory to be able to verify ourselves, and
to observe with ail their peculiarities, as I had the advan-
tage of doing in experiments on the same subject made at
Mr. Treraery's, in concert with Messrs. Berthollet, and the
particulars of which I have given in a preceding part of my
work.

From the action which a point, or the edge of any body, E/^h particle

^ . " , of matter sur-

exerts on the luminous rays, it seems to me we are author- rounded by an

ized to consider eacli molecule, or distinct parcel of matter, attractive
as enveloped with a double sphere of activity in respect to j^ and'arepul-
light: one more interior, in which the rays are attracted by sive sphere ex-
the body; the other more exterior, in which the rays are re-
pelled. Now it will happen, that, in several positions, a
ray, coming to traverse the repellent sphere, will describe:
there a curve convex toward the body; that, if it afterward
penetrate the attractive sphere, the curve of deviation will
be concave toward the body ; and that it will a second time
become convex toward it, when the ray repasses into the
sphere of repulsion, to continue its course. Here we have
the commencement of an undulatory motion, the curves of
which may be multiplied by a series of molecules.

., Would this cause be sufficient, to effect the fits of easy Is this the cause
reflection and transmission of the rays directed to the sur- ^^^y refle'ction

face of a body.!* &transmi,sion?

The phenomena of colouration here considered appear to Probably it is.
tne, to be very naturally explained by this simple mean:
yet I merely announce it as a probability. To leave no-
thing to be desired in such a proposition, no doubt more
profound investigation is necesi«ary ; as well as in particular
to put it to the test of calculation, in order to see, whether
it be possible by the attractive and repulsive powers ascribed

* Opt. lib, 5, qusst.. 3.

K 2 to

132 ON COXOUES OF THIN PELLICLES.

to each molecule of a body, in a case given to deduce the
motion of the luminous rays repelled or impelled now in one
direction, now in another, conformably to the reflections or
transmissions produced by pelHcles.
The same co- It is of more importance to my object however to reraaik,
lours ; roduced ^i^,^^ ^| i ..g .^y\^\^^^ from fits of eusy reflection and trans-
b^'twe, II bodies _ ° /^ "^ ,

in a vacuum, mission are equally produced, as Mazeas very justly ob-
served, betAvcen the surfaces of two bodies brought near to-
gether, witliout the interposition of any matter, as in two
lenses, or two pieces of glass, applied to each other in the
vacuum of an airpump.
And in thick On the other hand these colours do not always require a
P ^-'^s. ^^^^,y. ^^^^Y distance of the surfaces, since Newton himself

obtained coloured rings by the action of two surfaces of a
concave glass mirror three lines thick; and found, that in
thick plates these rings depend on the ratio of the thickness,
according to the same law as he had determined with respect
to thin plates; which he confirmed by the observation of the
rings of a mirrOr only one line thick.
Colours of pel- ^^^ ^^^ *^^^" ^-*y comparing the various phenomena I have
licles indepen- mentioned, that the prismatic colours of a pellicle, or a thin
dautof ; icsu - pj^^^^ ^f glass, are as fugitive and independant of the proper
colour of the substance, as those of a thick piece of glass :
and of its thin- that those colours even may not depend on the thickness in
uess. jjjjy respect, as when they arise in the interval between two

glasses brought together, or in the fissures of certain mine-
Analogous to ^'^^s • *^^^* ^^^^y ^^^'^ ^^^ greatest analogy with the rings pro-
the rings iava- duced in a mist, in smoke, or in the intervals of threads
tween'onake impermeable themselves to liglit: and finally, that, if we
substances. trace it up to the action of a point, or a single particle of
And m?y be matter, on the luminou? fluid, we shall there find a very pro-
aTtton of par- bable origin of the modifications of the direction of the
tides of matter rays, that are deflected by the particles of bodies in the dif-
°" 'g t, ferent instances quoted, and which, being -difl^erently influ-

enced each according to its nature, ultimately escape in a
diflerelit direction. Hence results a variety of colours on
without any these bodies, determined solely by the number or distance
the'ir n^tu're ^^ ^^^'^ particles, without any relation to their nature.
Colours of bo- Let US now proceed to establish^a parallel between these

• sorts

ON COLOURS OF THIN PELLICLES. 133

sorts of colours, and those of the particles of bodie* sub- 'lies that ab-
jected to the laws oi" absorption. ■^^'^ ^*

In the first place with respectto the latter the luminous The pencil not
pencil is not divided as in the former. The rays that do not ^'^^'^•'^ ^^'■''•
reappear in a given direction are not thf-own into another di-
rection ; they remain absorbed in the substance, even when
the mass is perftctly transparent.

In the next place the colours resulting from absorption The colours

are sometimes owins: to grrouus of rays very different from differ ^rom

„? , ^ ',. . , T- . . , tliose of pelU-

those that tnin pellicles can lurinsh. Tor mstance, these (,ies.

never produce a compou.id colour like that of bodies tinged

violet by oxide of manganese, or like the blue of cobalt or

of indigo. Besides in these two kinds of phenomena there

is no relation between the progress of colour depending on

the degree of thickness.

Thirdly the colours of the thinnest pellicles are very vivid. Are impercep-
Those of the most intensely coloured solutions on the con- ^^^^"^^ thia.^*
trary are imperceptible when so thin. It is for this reason
the colour of extremely thin leaves of mica has no relation to
the yeliow or other colour of the ma^s from which they are
separated ; they resembling pieces of the m^ost colourless
glass of similar thinness, so tliat mixed together they would
not be distinguishable.

Thus glass, mica, or any other substance, which when Substances co-
very thin is invested with the most brilliant colours, pa-ses ' -"^^^ Y^'^?
to a colourless state by lacreasmg its thickness, or to a co- waen thicker.
lour iadependant of that displayed by it w hen thin.

But it may be said, to compare a coloured mass to an Molecules of a

assemblage of parcels of a determinate thickness, these g'^en thick-

. , IT ness, kepr at a

parcels must be kept at a suitable distance from each other, given di tance.

In this case, I should answer, you will have a certain co- yf^,old reflect
lour reflected, aad another transmitted, which is precisely ou^i roiour,
complementary to the former. Now this double colouration '^^ opposite.
never takes place in perfectly diaphanous substances.

The examples of the infusion of nephritic wood and pre- infuson of

cipitates of gold are not more applicable to this case, since, nephn?,c wood

11 1 ^1 n . n \ • • 1 & preci; itates

as 1 iiave shown, the redected colours are owing to particles of gold, u .ake

impermeable to hght, and disseminated in a transparent panicLs in a

fluid ; and we may alter the nature of these particles, or even liuidf ^"^^^

have

134 COLOURS OF HEATED METALS.

have others, so as to change the reflected colour, without any
alteration in the transmitted colour.

Hitherto there is no case known, that allows us any foun-
dation to consider a body that is perfectly transparent, or
even a httle turbid, as composed of parcels of a given thick- -
ness, and kept at a necessary distance, in order to produce
a colour dependant on the thickness of its elementary
parts.
Colours of pel- Lastly the colours of pellicles are in certain cases variable
the incliiiatioiri ^Y *^'^ inclination of the light and of the eye, and some-
oftherays,and times too by the influence of the mediums with which they
medium.^ are in contact. Nothing similar to this takes place in the

colours proper to the particles of bodies; for these are fixed
and permanent in whatever direction we look at them, and
are equally unchangeable by immersion in a dilferent fluid
medium of less or greater density.
Permanent co- These characteristic differences I conceive are sufficient
haveadrff" ^nl ^^ authorize the opinion, that the colours of substances in
capse. masses have not the same origin as those of thin pellicles ;

a conclusion as important with respect to its object, as to
the difference of opinion that still subsists on it amoi\g the
learned *.

I shall conclude with some observations on two curious

kinds of phenomena, analogous to the subject, which I think

I have sufficient grounds to explain in a manner different

from that'generally admitted.

Colours of ' The first relates chiefly to the colours of annealed steel.

heated steel, Newton has ranked these amone those that depend on co-
referrid to the , , . „ . , . . , . .

same cause by loured rings; not irom a particular exammation, but simply

Newton J as a consequence of the system he had formed, supposing

that the magniturle of the metallic particles must have beea
altered by the action of the fire. He did not consider whe-
ther thete were any jother causes, between which a choice was
to be made,
to oxigenation lyiore modern philosophers on the contrary have ascribed
dlxns' "^°' tl)ese colours without any hesitation to a different degree of

* See among others in the 2d edition of Berth oil et's Elements of Dye-
ing, and the 2d edition of Haiiy's Treatise on Natural Philosophy, the
discussions and opp<5'sife bpinions of theffe celebrated authors on this,
question, > -

oxidation,

COLOURS OF JIEATED METALS. 135

oxidation, because they have supposed they observed a great
similarity between the appearances in question, and those of
several metals placed in circumstances under which they are
actually oxided. This subject however deserves at least a
closer examination, and the following is the simple method
I have pursued.

1 held a steel watchspring across the flame of a candle a A steel watch-
few seconds in a fixed position. After it was cold and clean- ^vThe flame of
ed", I found both on the right and left of the central point, a'candle
where the flame had been, a series of colours more and more acquired the
faint [degradees], with periodical recurrences, such as would P"sniatic co-
have been exhibited by a small band cut precisely from the ly in concen-
middle of a circle formed of a series of concentric coloured ^"*^ ""^*
rings. The nature of the phenomenon then is very dis-
tinctly shown here, particularly as the exterior ring was
nearly 3 cent. [1 1*7 lines] in diameter, and the others de-
creased interiorly with intervals of a few millimetres. No-
thing was wanting to have completed the circles, but to have
operated on a bioad plate of steel suspended horizontally
over the point of the flame.

Not having such a plate at hand, I took a sheet of tin, A sheet of tin
which, with appearances analogous to the preceding, af-
forded very vivid colours in consequence of its natural
whiteness.' With a proper degree of inclination the colours
are most lively ; particularly tlie yellow, I'ed, and blue, which
form together a spot, in which the blue occupies the centre,
surrounded by the red, and beyond this with the yellow, with
the intermediate tints and gradations.

There is nothing in the property tin has of being oxided Not fromoxi-
and forming salts, that indicates colours corresponding with "^^''^'^'
these : on the other hand the periodical recurrences on the
steel spring evidently belongs to a series of rings : we must
conclude therefore, that this phenomenon is simply of the
class of coloured rings.

Another trial made with a gold ring equally produced re- q i j ^u
peated traces of rings, and here the suspicion of oxidation
will hold still less.

A copper wire gave me similar indications, though more Copper and
faintly; but I have observed them very striking on copper
chimneys of stoves. Lead that has just been melted ex hi- lead similar.

bits

shows this
more plainly.

i^

COLOURS OF HEATED METALS.

Caloric has not
altered the di-
nien-ions of
the panicles,

but separated
them progres-
sively.

Similar effects
from altering
the arraiijre-
ment of the
particles oi bj-
dies.

Proof of this.

These effects
shown in a
striking man-
ner.

bits the same kind of colours, according to the circumstances
of its cooling, even ou its lower surface not exposed to the
air.

With regard to the manner in which caloric acts on the
metal in these instances, 1 will not say, that it has altered
the magnitude of the particles; for how can we conce.ve,
that a substance can vary tl^e disposition of 4;he constituent
elements of its molecules without changing its nature? But
I can more readily conceive, that there has been a progressive
separation of the particles, increasing from the part scarcely
heated to that in immediate contact with the flame. This
separation, from the principles I have laid down, must in fact
have been sufficient to produce these rings.

Besides, we daily see many examples of this sort of co-
lours, where the arrangement of the particles appears to be
the sole determining cause. Such are the spots formed on
knife blades by the acid on fruit; those on silver by sul-
phurous vapoiirs, or the continued contact of certain subr
stances; and the prismatic colours of pellicles forpied on the
surface of liquids coritaining some matter at first dissolved,
and afterward precipitated slow^ly by the gradual evaporation
of some volatile principle, seen in manuiactories and labo-
ratories. The waters of dunghills are sometimes covered
with similar colours.

Now all these effects, whatever be the nature of the pri-
mitive matter, or of that secondarily formed, depends only
em the arrangement of the parts. Nothing is more easy than
to ascertain this. Scratch the surfaces, break the pellicles,
and all this tnultitude of colours will be annihilated, the frag-
ments of each leaving only particles uniformly possessing
the common properties of their kind.

• The following among others is a very convenient mode of
observing these effects. Take a small quantity of Schetle's
green, dissolve it in an acid, and, after having largely diluted
tiie solution with' water, precipitate by an alkah, and add
ammonia merely to rediscolve the precipitate. Let the whole
stand in a ve sel not closed, and in a few days the surface
w;U be covered with a' very evident coloured pellicie, in
yi^hich periodical recurrences of rings wdl be distinguished,
if it have remained undisturbed. This pellicle may be taken

up

ON CHANGEABLE COLOURS. 137

up by sliding underneath It a piece of paper, or of glass, as
the side of a funnel for instance, to allow the water to run
off. The colouvs of the pellible will continue visible after
it is removed ; and by lettin;^ the matter dry slowly we may
preserve them for an indefinite time with all their vividness.
But if we pa^s the linoer lightly over il, we shall collect
nothing but a green powder: the red, yellow, blue, and
purple, that appeared so brilliant, will be gone in an in-
stant.

My second phenomenon respects the changeable colour of Changeable
several pai ts of the plumage of the peacock, and of some ^j^g^s. ' ''

other birds, as the cock, pigeon, duck, and turkey. Here,
after a very deliberate compar;»rive examination, and the *

most circumspect reflection, I have ultimately relinquished
the idea, that the^e colours are to be referred to rings. My
conviction was produced as follows.

In the iirst place 1 considered, that these colours were not Not owing to
-the necessary result of a certain tenuity of parts; for on the ^®^^"^'y*
one hand several animals incontestably display in the slen-
der filaments of their hair, feathers, or dowii, various de-
grees of teiiuity, Irom tlie most imperceptible, vvitirout its
producing colour. Is not the white peacock itseif a staking
instanct of this?

On the other hand have not many birds and insects co-
lours unchangeable in situation and iii tlieir reflections in
every point of view? 'i hose ot the wings of some butter-
flies are peifeciiy tixed, tiiough dependant on a down so tme
as to be scarcely visible, it is likewise proper to remark. Ail o^^ake ex-
that all these colours indicate opacity, as those of the jxa- ^^-!'t^'''« wings
cock s feathers ; the wii.^s oi flits excepted, in which tints
analogous to coloured rings are observed : but iheae mem-
branes have a sensible tiani&pareucy, like scales of niica or
blown glass.

I alterward observed the change of colour of several fea- Feathers offhe

thers of the birds mtntioised. in those of the peacock's pe^^^^^^'^ i^'l*

tail, we see the lateral liiaments, on ciianging their position,

pass suddenly from red to green. 1 he red is produced by Redbyper-

a nearly perpendicular rellection of li<4hl,.the srreen by a l'^"^'cular,
,,.,,. , , . , °. "^ screen by ob-

very GblLc^ue retiection ; and there is no alternation of re- liquc reflection,

flection

J 38 ON CHANGEABLE COLOURS.

flection and transmission, the opacity of which I have spoken

not admitting it.

Eye of the fea- Near the eye of the feather an external ring exhibits yel-

♦h^'"* lowish tints by perpendicular reflection, and greenish by

oblique reflection ; while more interiorly, with the same

change of obliqueness, a space of the most vivid green takes

the new tint of violet. These are the principal mutations

of the colours, consisting oaly in two tints for each place.

Figeon*s neck In a feather from the neck of a pigeon, the disposition is

»h reverse of ^^^ reverse of that of the lateral filaments of the peacock's

the peacock s , ^ ...

lail. tail feathers : that is to say, under similar circumstances,

one of these feathers appears red, the other green, and vice

versa,

Tbe variation This alternation of colours, confined to two principal kinds,

confined to two • difficult to reconcile with that variety of tints, which

•olours. - . ..."

coloured rings apparently slrould exhibit m a substance of

so little density as feathers. And if it were attempted to be
supported by the more sensible changeability of tints in the
pigeon's feather, this would arise from a deception ; for this
changeability is owing to the naturally curved stale of the
feather, since it ceases when the feather is straightened
against a flat surface.
Feather of a But the feather of a duck's wing exhibits an appearance
buck's wing, totally dissimilar. Here the transition is from green to
blackish; and this green is not perceptible except in parti-
cular positions, in which the incidence and reflection of light
take place under very unequal angles, as for instance, when
the feather is seen with a certain degree of obliquity, the
spectator's back being turned to tlie light. Do we meet
with any thing like this in the succession of coloured
rings ?
Eyeofthe-pea- Lastly J bethought myself of wetting with caution difler*
cock's feather ^^^ parts of the eye of mv peacock's feather. I then saw,
weftedjshowed ^ , • r. i • ' , - i ,

new colours not a weakenmg oi the lormer tmts, but new colours

brought out with great vividness. Desirous of knowing
•rliich were the whether I could not produce permanent alterations by some
jamewithvari- solvent, I wetted it successively with saliva, vinegar, muri-
' atic acid both dilute and concentrated, ammonia, ether, al-
cohol, and deliquesced muriate of lime: and I found, that
they produced no eflect except as fluids, and all nearly

equal.

ON CHANGEABLE COLOURS. 130

«?qua], except the concentrated muriatic acid, which showed

some diflference; and all their effects ceased nearly alike on and disappear-
- , ed on drying,

arymo^.

When the exterior orbit of the eye was wetted, its yellow- The colours
ish colour became of a lively blood red; and the reflection, thus produced,
which was before p^reen when seen obliquely, was almost de-
stroyed. If the green space within were wetted, it was the
violet reflection that disappeared. Lastly with smoking mu-
riatic acid this green space viewed perpendicularly exhibited
a yellow inclining strongly to red, and the oblique reflection
changed at first to green, and then it passed on to violets
none of these changes however continued permanent.

By wetting in this manner the extremity of the feathers Feathers of a
of a turkey's tail, I brought out very vivid new colours, ^^ ^^ ^
which could not be perceived before in the same direction ;
Jbut the existence of which was indicated by certain reflec-
tions when viewed with the back to the light, analogous to
those I mentioned in speaking of the duck's feathers.

It was impossible for me, after all these particularities, to Perhaps from

persist in classing together the changing colours of feathers, ^^'^^ ^'^y^!'^°^^'
W' A,u ^.U 1 J • c u- ^ A r. 'rionofdiffer-

c; una those ot the coloured nngs ot pellicles. An otten re- ent coloured

peated examination of them at length suggested the idea, substances.
that they might arise from the superposition of different co-
loured substances, sometimes of two only, or of three, or of
a greater number ; nearly as if, wishing to paint a body with
several colours, we were to cover it in succession with a stra-
tum of each of the proposed ingredients.

. This supposition, suitably adapted to each part of the This Hlustrat-
feathers, very well accounts for all the appearances observed. ^^•
In fact, if over a coat of green paint for instance we spread
a thin stratum of a violet powder, it is obvious, that on look-
ing directly at it it will appear almost wholly green; while
on lowering the eye, so as to view it obliquely, the violet
will gradually predominate, till at length it alone is seen.
The intermediate tiuts will be different shades of green, to
which various shades of blue will succeed, before the violet
will appear.

' If in addition to this the green itself be laid on a red
i ground, this may remain invisible in the intervals of the co*
, loured matter of the superior strata : but if these strata be

rendered

J40 DETONATING SILVER.

rendered transparent by imbibing a fluid, the influence of
the lower stratums will be perceived, and will naturally
show itself here by a yellow or reddish colour, when seen
perpendicularly, while its oblique reflections will exhibit
^eenish or violet tints ; and the drying of the substaiice will
restore every thing- trt its former state.

Such in reality are the variations of the tints of certain
parts of a peacock's feathers: and such in my opinion is the
probable cause of their formation, which is equally applica-'
ble to those of the cock, the pigeon, and several other birds,
as well as to insects, and in particular that splendid but-
terfly, the large wings of which exhibit a fine green, when
\-iewed perpendicularly, and when obliquely a beautiful
violet.

XV.

Account of a Fnhn'inating Compoimd of Silver, of a white Co-
lour mid Crystalline Appearance : hy Mr, DEaCoriLS*.

Det&natin^ m\. Detonating powder has been sold lately at Paris as an
powder lately object of amusement. It is enclosed between the folds of a
sold, at Paris. , . ' i • i i i •

card, cut in two lengthwise; the powder being placed at one

end, ar.d tlie other being notched, that it may be distin^
guished. If it be lakeu by the notched end, and the other be
held over the flame ol a candle, it soon detonate.?, with a tharp
sound, and vio et flames. The card is toin, and changed
brown ; and the part in contact with the composition is co-
ve; eel with a light metallic coating, of a gra] ish white colour.

» ~. J Having: been consulted on the imture or this substance,

A componnd " .

of oxidL. of sil- which is sent to Paris ready prepared, 1 convinced myselt by

-sjr, ammonia, various tr'als, which it is unnecessary to relate, thatlt is a
and vegetable , . . , .•

matter. comy»ound of oxrie ot bilver, ammoiiia, and some vegetable

matter; su that it is analogous to the fulminating mercury of

Mr. Howard.
Methods of This couipound, which I call dKonating silver, to distin-

making it, g^j^]-, \^ f,.(jjjj the fulminating silver of Mr. Berthollet, may

♦ Annales de ChimiQ, vol. LXII, p. 198, May, 1807.

be

DETONATING SILVER. 141

be made by dissolvin«^ silver in pure nitric acid, and pouring

into the sobitiou, while it is goin<? on, a sufficient quantity of

rectiiied alcohol : or by adding alcohol to a nitric solution of

silver with considerable excess of acid.

In the first case the nitric acid, into which the silver is put, Poumitricacid
1 1 -11 1 1 • ' >l1 i • oi^ Sliver, heat

must be heated gently, till the solution commences, that is [^ gently,
tin the first bubbles begin to appear. It is then to be re-
moved from the fire, and a sufficient quantity of alcohol is to & add alcohol,
be added immediately, to prevent the evolution of any ni-
trous vapours. The mixture of the two liquors occasions an
extrication of heat; the effervescence quickly recommences,
without any nitrous gas being disengaged; and it gradually
increases, emitting at the same time a strong smell of nitric
ether. In a short time the liquor becomes turbid, and a very
heavy, white, crystalline powder falls down ; which must be
separated, when it ceases to increase, and washed several wash the p'reci-
timeswith small quantities of water. pitate.

If a very acid solution of silver previously made be em- Or to a heated
ployed, it must be heated gently, and the alcohol then added, ^^'^^add dcu-^'
The heat excited by the mixture, which is to be made gra- hoi.
dually, soon occasions a considerable ebullition, and the pow-
der immediately precipitates*.

This powder has the following properties.

It is white and crystalline; but the size and lustre of the xts properties.
crystals are variable. Light alters it a little. Heat, a blow,
or long continued friction, causes it to inflame v/ith a brisk
detonation. Pressure alone, if it be not very powerful, has
no effect on it. It likewise detonates by the electric spark.
It is slightly soluble in water. It has a very strong metallic
taste.

Concentrated sulphuric acid occasions it to take fire, and Action of I
is thrown by it to a considerable distance. Dilute sulphuric phuric acid oa
Acid appears to decompose it slowly. *^*

V Muriatic acid, whether concentrated or weak, decomposes Of muriatic.
it immediately, and forms w4th it muriate of silver. The
quantity of muriate it produces indicates, that it contains

..about 0-7] of metallic silver. A pretty evident smell of Smell of pru$-

sic acid.
* It would be superfluous to remind the chemi-t, that the mixture of
^alcohol with hot uitric acid is liable to occasion accidents, and that it is
consequently prudent, to operate oa small quantities.

prussic

442 MEANS OF ASCERTAINING THE QUALITY OF GLASS.

pruBsic acid is perceived the first rnoment of the mixture,

bat I never could discover any traces of it.

Decomposed Nitric acid decomposes it by the help of a bailing heat ;

y nitric aci ; ^^^ ^^^ products are nitrate of silver, and nitrate ot ammonia,

if it be continued long enough.

sulphuretted It is decomposed by sulphuretted hidro^en ; the ammonia

*= ' and vegetable matter remaining in the liquor.

and potash. Caustic potash decomposes it ; black oxide of silver being

separated, and ammonia di sen ganged.

Ammonia dis- It is soluble in ammonia; but by a slow evaporation it
solves It with- . ... . .

out alteraiion. may be separated from it, retaining its original colour and

other properties, particularly that of detonating by heat, and
not by simple contact.
A virulent poi- Its most important property to be considered, with respect
to the use made of it, is its action on the animal econom}'.
Mr. Pajot-la-Foret, who has made a great many experiments
on this subject, has found, that very small doses are suffi-
cient to destroy pretty strong animals, as cats. They all
expired in the most dreadful convulsions. It is unquestion-
ably one of the most violent poisons to be found among me-
tallic compounds.

XVI.

Memoir on the Means of forming a Judgment of the Quality

" of Glass, particular Ii/ Window Glass, and distinguishing

such as is liable to alteration: by Mr, Guyton. Read at

the General Meeting of the Society of Encouragement,

March the Uth, 1807*.

son

Prize proposed ABOUT two years ago Mr. Guyton suggested to the
for a test of societj^ to propose as the subject of a prize, a ready method
good glass. of ascertaining the goodness of window glass. It appears,;

that, from the negligence or ignorance of the glass maiiufac-
Frenchwin- t^rers, tlie windows in several large houses had become dis-
dow glass liable figured in a few months by a spontaneous alteration of the
^ ^P°'** glass, which destroys its transparency : accordingly it \^as of

some importance, to be able to guard against this inconve-
Jhe question jiience. The prize was proposed, and its term prolonged;

• Abridged from Anaales de Chimie, vol. Ixii, p. 5, April, 1807

but

MEANS OF ASCERTAINING THE QUALITJ OF GLASS. 143

but no paper was sent ori/ the subject. This led Mr. Guyton unanswered,
to investiiJ^ate it himself.

With respect to the general characters of glass he observes, Specific gra-
the specific gravity of different kinds of glass, all of which
may be good, is very various ; beside which, to ascertain it
requires nice instruments, and an expertness in their use not
commonly to be met with.

The inspection of the fracture affords but a loose conjee- Fracture,
ture to the most experienced eye : though Mr. Ducloseau
asserts, that the friictm-e of good glass is always wavy, and its
angles more or less acute.

The degree of hardness varies not only in different kinds Hardness.
of glass, but in glass of the same kind. Workmen used to
handle the diamond readily distinguish glass that cuts soft,
from that which cuts hard; so that this might seem a suffi-
cient indication of its good or bad quality. It is very difficult
however to discriminate degrees of difference in this respect,
neither is it always to be depended upon.

Glasses that are called greasy [gras] are bad insulators of Bad glass not a

electricity, and little capable of bein«j rendered electric by P^^'^f ^^ "°""
'' . * ... "^ conductor of

friction. Probably this, as well as their being liable to alter, electricity;

depends on an excess of saline flux, or an imperfect refining,

that has left sandiver in them.

Bad glass placed on burning coals becomes dull and more and tamlshedl
or less meally on its surface. The same effect is more spec- ^ ^'^^^'
dily and evidently produced before the blowpipe. But in
all such trials we have to guard against the too rapid or too
unequal action of the heat.

The experiments Mr. Guyton made with neutral salts Neutral salts
convinced him, that this mode of proof, which would have ^f ""'^ ^^^ °*'
been very convenient, was altogether inefficacious. Among
the specimens of the commonest window, glass however,
which is in general unalterable, he found one, that underwent
a perceptible change on its surface by merely boiling in a
solution of alum and mutiate of soda.

There are few glasses, which^ when reduced to an impalp- Acids acton

able powder) are not slightly acted upon by concentrated P°^^'<^^'-''^^'^ S^^^^

acids : though previously all well made glass resists sulphuric

acid, the most powerful of all, even assisted by heat. On 3^^ gj^^^ ^^_

the contrary it very readily attacks puss of bad quality, at roded by sul-,

., phuric acid.

144 ^^ VlTROUS ETHER.

tlie common temperature. I liave seeh^ says Mr. Giivton,

Iblack iJ^lass bottles, into which ronrentrate<l sulphuric aci(i

had been put, perforated with several holes in the course of a

few flays; which, bein^ largest interiorly, exhibited there

white, sUlvy excrescences, formed of the acid united with

T^. J the soluble earths of th6 elass. But all elass susceptible of

This a good ... . . ^ . i p • . •

test. alteration m the an* is not of so defective a composition ; so

that to form a judgment of it, the acid must be digested

upon it, and the heat carried so far as to raise the acid in

vapour. When this is done, it will leave untouched only

well made and well reflned glass, whatever be its nature,

transparency, or colour.

But may be Sulphuric acid then fulfils all the conditions required for

neglected from a test. I foresee liowever, that this chemical instrument

^^^* will frequently be ne<^lected, from fear of the accidents, to

which they may be exposed, who are not in the habit of using

it with caution. This has led me to substitute an agent

equally powerful, that may be procured more easily, and

employed without any danger.

Easy mode of This ageiit is sulphate of iron, the green copperas of the

ascertaining its shops. After having put into a small Hessian crucible, or

sulphate^/ any other of stoneware, shps of the glass to be examined,

iron. either alone, or comparitively with others, let the crucible be

nearly filled with this sulphate coarsely powdered. It may

tben beset on the fire, and kept there till the metallic salt

has acquired a red colour. When the glass is grown cold,

it only requires to be immersed in water, which will shovr

whether it will be altered, and in what degree.

This process is not expensive, requires no^pparatus, and

is in eveiy one*s power ; and the results I have obtained

appear to me to leave no doubt of its advantage.

XVII.

Iteport on a Paper on Nitrous Ether, read to the Institute the
4th of August, 1806, by Mr. Thenard, Professor in tJie
College of France. By Messrs. Guyton, Vauquelin,
and Berthollet*.

Various eibcrs. ^ ARIOUS kinds of ether have been formed by the ac-
tion of some of the acids on alcohol. Volatility, inflamraa-

• Annales de Chimie, vol. Ixi, p, 282, March, 1807.

bility,

ON NITROUS ETfTER. l4^

bility, and a peculiar smell, ^ive to them all a common cba^ Have a com-

, „ n 1 .1 '^1 i.1 tnon cyiuracter.

rp.cter, which does not allow us to confound them with other

substances: yet we have pnly an imperfect knowledge of the Yet differ,
differences that distinguish thew, and our theory of their
production is perhaps still more imperfect. It is trn«
Messrs. Fourcroy and Vauquelln have thrown much light
on the production of sulphuric ether ; but tlieir explanation
does not admit of being extended to some others. It wM
of importance therefore to resume this subject, and treat it
in a general manner. This Mr. Thenard has undertaken.
In the first paper he has presented to the Institute he treats
on nitric ether; from this he intends to proceed to others J
knd he will examine why some acids have the property of
producing ether, and others have not.

The processes recommended by different chemists for the Various pro-
. 1 , . 1 T./r mi 1 • , ceases ofmak'

production of mtnc ether, which Mr. 1 henard reviews, are ji^g jj,

tery discordant, and have no other object than the ethereal
liquor to be obtained, without any analysis of the gaseous
products, or any consideration of the circumstances of the
process; if a memoir by the Dutch chemists be excepted,
^hich Mr. Thenard examines particularly at the conclusion
of his own. Accordingly he found himself obliged to treat
his subject independantly of the labours of others.

Mr. Thenard began with distilling a mixture of equal ^/^"^/^i^^^f]'^^
weights of alcohol and nitric acid, both of given strengths, in and alcohol
an apparatus adapted for the separation of the flluid from the ^^stilled.
gaseous products. A gentle heat is sufficient; and indeed
the action soon becomes so brisk, that it is necessary to slip-
press even that. He afterward examined the residuum in
the retort, the fluid product, and the gasses.

The residuum was composed of nitrous acid, acetic acid, Residuum,
alcohol, water, afld a small quantity of matter, the nature of
which is uncertain, but which is easily carbonized. The pro-
portions of these he ascertained by ingenious and accurate
methods. If the distillation be carried on to dryness, the ,

tiscouS residuum contains oxalic acid, and probably malic.

The distilled liquor, which is considered in the shops as The distilled
. , . ^ . . hquor, onm-

nitric ether, is composed of water, nitrous acid, acetic acid, pure ether.

ether, ..nd probably alcohol.

The gaseous product in particular required miich patrence Masses produ-

VoL.XVIII-OcT. 1807. L and*"^"

145

ON NrTROUS ETHER,

and ability, to separate it into its dilferent elements, to as-*
sign to each of these the properties dependant on it, and to
explain the differences that result from the circumstances iu
which they are placed. It was composed of nitrous ga^',
a2ote, oxide of azote, nitrous acid gas, carbonic acid, and
etliereous gas, whicli it was particularly necessary to separate
from the rest, in order to examine its properties. By these
experiments, wliich may be termed preliminary, the author
was led to the following process for separating the pure ether,
and examining it, either in the liquid or ga-^eous state.
Mr.HienarcTs ^^^^ * retoti: he put five hectogrammes [l6oz. 48grs. troy]
jjrocess, of alcohol, and as much nitric acid, and adapted to it in suc-

cession by means of glass tubes five tall bottles half tilled
with a saturate solution of muriate of soda. In the last was
a tube opening under ajar to collect the gaseous pait. All
the bottles were surrounded with a mixture of pounded ice
and salt, which was stirred occasionally. To commence the
operation a little fire was applied, but it was soon necessary
to extinguish it, and even to cool the retort.

The fluid left in the retort was similar to that of the first
experiment already mentioned.
The ether pro- ^^ ^^^ surface of the solution in all the bottles was found
duced. a yellowish liquid; which weighed, when the whole was coU

lected together, 2^5 gr. [8 oz. 98 grs]. That in the first
bottle was a niixture of alcohol, ether, acetic acid, and ni-
trous acid : t,hat in the others was nitric ether free from al-
Its properties, cohol. The nitric ether in this state has a strong smell: it
is specifically lighter than water, and heavier than alcohol :
dissolves in any proportion in the latter, but requires near 48
parts of water to dissolve it, and at the same time is partly
decomposed by it, as will appear below. It possesses the
property of combustibility in a high degree; yet it strongly
reddens infusion of litmus, owing to a little nitrous and ace-
tic acid that it retains, and which may be separated by
means of lime.

_ - , The volatility of ether thus prepared is so great, that it

Much more "^ r i • ' , p , ,

vblatile than indicates a tension of 0*73 of a metre, while that of the best
srulphuric. sulphuric ether, under the same circumstanes, is but 0*46 of
a metre, at 21" of the centigrade thermometer [705 F], and
at 0-76 of a metre [29*7 in.] of atmospheric pressure. At

this

ON NITROUS ETHER. 147;

this temperature, and this pressure, therefore, it is at the
limit of its existence in the liquid state.

But if nitric ether be deprived of its acidity by means of Soon becomes
lime, it scon becomes acid again, whether it be redistilled,^^^ '
left in contact with the air, or kept in full and closed bot-
tles. This formation of acid takes place, when ether ia
treated with water, particularly at a temperature from 25* ta
,S8<^ [77° to 86^']. The author explains the formation 6f this
acid by the reciprocal action of the principles that constitute
etlier, and which are found to be feebly retained in it by
combination.

Mr. Thenard next proceeds to the decomposition of Analysed by
nitric ether by heat, and analyses the gasses arising from it. ^^**
Founding his calculations on the most accurate data we
possess, the result is, that 100 parts of nitric ether, rejecting Its^con^po^ent
fractions, are composed of azote iG, carbon 39, oxigen 34,
hidrogen 9«

Hence he infers what passes in the reciprocal action of Action of nitric
alcohol and nitric acid. The oxigen of this acid combines ^^^^^ on alcohol
with a great part of the hidrogen of the alcohol, and with a
very small quantity of its carbon. Hence result, 1st, a
great deal of Water, a great deal of gaseous oxide of azote, a
little carbonic acid, a little nitrous acid and nitrous gag:
2dly, the separation of a small quantity of azote, and the
formation of a great deal of nitric ether, by the combination
of a pretty large quantity of the two principles of nitric acid
with the alcohol dishidrogenized and slightly decarbonized :
3dly, the formation of a little acetic acid, and a small quan- ^

tity of a matter easily carbonized, by the combination of a
part of the hidrogen with carbon and oxigen.

Supported by these deductions, Mr. Thenard discusses pormer pro
the processes published before him for obtaining nitric ether, cesses, some
and he shows, that some are dangerous to attempt; that none *^''^'^S^'^°"*>
of them furnish the whole of the ether, that mi«ht be ob- all wasteful,
tained from the same ingredierits ; and that all jofthena yield ^^^ ^^^ ^^j^ej
only more or less compounded licjuors, in which the nitric impure,
ether, though they bear its name, constitutes but a part.

The Dutch chemists have published some interesting re- Thehypoihe-
searches on nitric ether, or rather on the gasses obtained by sis of the
the action of nitric acid on alcohol. But to explain the mis^s^e^rrone-
L 2 . curious ous.

248 ^^ SUBTERRANEAN HEAT.

curious facts they have made known, they have employed an
insufficient hypothesis. 1st, Tliey have considered the gas
in question as a compound of nitrous gas and ether ; while it
is composed of gaseous ether, nitrous gas, nitrous add, azote,
oxide of azote, carbonic acid, and acetic acid, in short of all
the substances capable of assuming the gaseous state, in the
various circumstances under which they are found. 2dly,
They have supposed ether to be a substance always identi-
cally the same, so that they neglected to analyse nitric ether,
atid establish its peculiar characters. 3dly, In consequence
of this opinion they have been led to ascribe to a preexist-
ing nitrous gas phenomena, that are owing to a decomposi--
tion of nitnc ether.
If the process After having discussed the opinion and experiments of the
•were varied, Dutch chemists, Mr. Thenard concludes his paper by ob-
would differ* Serving, that he has considered only the products and phe-
nomena obtained by given proportions, and under certaiw
circumstances. The effects must be different, when these
are varied ; and he intends to subject them to experiment :
but that above but he has already satisfied himself, that those he has em-
given the best, pj^ygfi ij^-e most favourable to the production of nitric ether.
The memoirs The committee concluded, that the memoir at large me-
InstiTutJ'^ ^^'^ ^^^^^ insertion in the Collection of foreign Papers, and the
class adapted their conclusion.

XVIII.

Ohservafions on subterranean Heat, made in the Mines of
Poullaouen and Huelgoat in Brittany : by J. F. Daubuis-

SON*.

Facts resoect- -^ HERE are few questions in natural philosophy, re-
ing the interior specting which we are more in want of positive and well esta-
earth^wantine ^^ished facts, to deduce consequences from, than that respect-
ing the temperature of the interior part of our globe, taken
at depths we are able to reach. I have already made known
some facts I observed on this subject in the Saxon mines.

♦ Journal des Mines, February, 1807, p. 119.

and

ON SUBT^ERRANEAN IIEAT. - l4g

, and I shall now give some othei-s noticed last summer in
Brittany. The habit of making aiinilar experiments, and
the knowledge" I had of the places, enabled me to choose
with some disdimination the points of which I ascertained
the temperature; so that I trust the facts I have recorded
will not be uninteresting to those, who make our Earth an
objeQt of their study. .

The thermometer I employed was of mercury, and di- Thermometer

y.yided into eighty degrees from the freezing to the boiling "^^ *
ppint of water. It was enclosed in a tube. 1 found by trial, 3'or 4'toalter
that when it indicated a given temperature, and was made ^^° ^- ^'^ ^'^^'
to deviate from this about a dozen degrees, it required thr^e
or four minutes to bring it back to the former point by \va-
mersing it in water of that temperature, and eleven or twelve ^ i' or 12' in
minutes if kept in the open air. Hence, whenever I was the air.
desirous of ascertaining the temperature of a body of water
in the mines, I immersed the thermometer in it entirely,-
and left it there five minutes; and when I took the temper-
ature in the air, I let it remain a quarter of an hour. All
the observations were afterward reduced to degrees of the
centigrade thermometer. Notwithstanding all the care and
patience I employed however, I cannot answer for their ex-
actness to less than a quarter of a degree.

Observations made at Poullaouen.

THE mine of Poullaouen is in latitude 48° I7' 49''' N., Situation and
and lon-itude 5° 06' ^l" West of Paris. Its mouth, that PoSuel^'^
of St. George's pit, is lOGmet. [347| feet] above the, level
of the sea. It is 4 myriam. [25 miles"| from the seacoast of
Brittany on the north, and 6 [SyJ miles] from that on the
south and that on the west. It is in that tongue of land,
which advances into the ocean under the form of a roof,
raised in its centre about 260 met. [853 feet] above the level
of the sea, and constitutes Brittahny. The country round
the mine, to the distance of near 6 miles, is about 150 met.
[490 feet] above the level of the sea; and is intersected in
eveiy direction by valleys, one of which is an almost circu-
lar basin about a millimetre [IO93 yards] in diameter, that
forms the roof of the mine.

k

According

1

150 ON SUBTERRANEAN HEAT.

Mean temper- According to tlie law of the temperature from th« equatotf

lation, ^^ ^^^^ pole, the mean temperature of the surface at Poul-

laouen should be 1^2-4® [5^-5° F.]*. The elevation of the

soil requires near 1® [l'8° of diminution, so that the mean

temperature may be estimated at 11*5"^ [50*9° F.]

Observations My observations were made the 5th of September, 1806^.

gept. Day fine. I^y^>"g the whole day the weather was fine, and but few

clouds were seen. The temperature in the shade, in the

middle of the day, was 19° [64*4° F,]. In reporting my

observations I shall mention the situation of the places where

they were made, as well as whatever appeared to me capable

of influencing the temperature. Opposite each expression

of the temperature I shall note the depth of the place below

the surface of the ground,

Tempe-
Tabulated !• I" the first gallery, called fifty foot /e- rature Depth

temperatures ve/, near the shaft, in a place where there was ^ . ^ ' '"§ 1^^^

and depths renn ri. in.

with remarks. ^"* ^ slight current of air, a little water that thermo

lay on the ground indicated 53*8° 52* »3

2. In St. George's gallery, under the inter-
section of three branches of the vein, in a kind
of cul de sac, very remote fora the places
where the miners were at work, in which there
was no current of air, but a lar^e quantity of

water filtered from the roof : this water' was • • 51*6° 127* '4

3. The ^ater that thus filtered into the gal-
lory,' when it reached the well from which it

was raised, was- • • . • 52^ ]27* '4

4. Thirty six metres lower, at the level of
Boullaye, toward the end of a long gallery,
where tliere was no current of air, and no per-
son at work, under very strong percolations

lind in the water 1 had 5r6<^ 244.10

* Theory and observation have led me to a very simple expression of

the iheriuQinetrical terjijperature of z, place, the latitude of which is

known. This expression is 30-7° [85 4^ F.]. cps. ^'zs latitude j or

"with sufficient exactnes&in the temperate zone 28® [80 6° F ]. cos. *

:iat. ' • ■'

•\ In the atmosphere the temperature diminishes 1° [18* F ] fs)r
every 175 met. [I9l yardc] in height. ,

'■■■"" •• • 5. At

ON SUBTERRANEAN HtAT.

5. At the bottc m oF St. George's shaft, in Tempe- Depth,
the well in which the watei-s that penetrate

into the lower parts of the mine around it are

rollected ....... .^ 55.7O 463 • '6

6. Tiie air over this water 57*2° 460.-3

7 In the well at the bottom of St. Barbe's

shaft, at the other extremity of the mine .... 54*5° 489. '6
' 8. In the air above this water 56-1^ 489. '^

9. The waters of the old excavations, that,
rah into this well • « . • * • • • • • 54*1?

N. B. These waters arising from filtratidns
that take place chiefly in the' upper parts of
the old workisig^s are cold; and as they form
the greater part of those that' enter into St,
Barbe's well , they av^ the occasion of the low-
ness of the temperature shown by the water
in it,

10. In an excavation but little distant from
the bottom of St. Barbe's shaft, called the
oven gallery, the sides of which are alnpst
every where interspersed with radiated pyrites
partly effloresced, the thermometer left a quar-
ter of an hour in a small hollow made in the
midst of the pyrites, and which contained a

great deal of white sulphate, indicated. ..... 56*5° 457

11. Afterward pint iijto a small hole, from
which a pretty strong spring issued, it equally
marked • • 56-5° 457

The observatlor)s 2, 3, and 4, incontestably prove, that
the heat of the rock in the upper parts of the mine is 51*8°.
The waters indicating this certainly acquired the tenipera-
ture of the rock in filtering through it; and this tempera-
ture does not dift^r in any sensible degree from that indi-
cated by theory. If the first observation shoved a little
higher temperature, it is because it was made in a place,
where air from without, and consequently warm, as the ex-
periments were made at th^ end of summer, was continually
passing.

Observations 5 and 6 show, that the temperature of th^

lower

151

Tabulated
temperatures
and depths,
with remarks.

General de-
ductions.

Superficial
temperature;
agreeable to
theory.

Temperature

152 ' ON SUBTERRANEAN HEAJ.

increases with lower parts of the niiue is ijaore> considerable than that of
* ' the upper parts. If in the cjeptbs the air a])pear hotter than
the water, it is probably because it has retained a part of
the heat it possessed wKen.it. enter^gl the mine. I have al-
ready pointed oui the reason why in 7, 8, and 9, the heat
was less than the depth requires.

Pyrites do not > Experiments 10 and 11 ,sl^oiy, that there are circum-

ahvays occa- stances in which the presence of pyrites does not occasion
sioa heat. i . i i • ,. V

heat. That which they indicated was not occasioned by

them, for in St. George's shaftj. where there was none, the
-.temperature was the same.
Heat increases Thus, setting aside every extraordinary cause, the ob-
^d° fV"th^ servations I have reported appear to me to indicate, that at

the depth of 150 met. [iCS yards] the temperature at Poul-

laouen is 2° Qr 3° [3*6° or ^?4J JF,,] ^ore^ than at the siir-

fiace.

Observations made at Huelgoat.

Huelgoat THE mine of Huel is in latitude 48° 18' J?"' N., lon^.

iniae. go j/ 45'/^ ^][^he opening of its shaft is 173 met. [188 yards]

above the level of the sea ; and is on a large hill, that sepa-
rates two valleys, the depth of which is 80 or <)0 met. [87 or
97 yards].

Me^n temper- From this latitude and elevatioJi we may infer the mean

Tatlon^' ''•'"" temperature to be 1 1° [50° F.]

Insciiist. '^^^ rock, like that of PouUaouen, is an argillaceous

schist, but it likewise contains some strata of aluminous ,
schist.

Observations The following are the observations I made on the 5th of

the same day. September, the same day as those at PouUaouen.

Tabulated 1» In a gallery about 16 yards below that Tempe-

^17.T ^ ^^[''^ the workmen commonly enter the "'^l ^^ '
^ith remarks, mine, into which no person had been for se- renh. Ft. In.
veral years, which has no other outlet, and in '
. which there was no current of air, a therna^)-
nieter at its northern end after twentyminutes

indicated 50^

After having descended the shaft called the
miners, and goiie a few dozen yards into Jthe

gallery

ON SUBTERRANEAN HEAT. ] 53

j^allery at its foot, I entered another shaft, Tempe- Depth. Tabulated
wliirh terminates in a gallery that hjas no com- ''^^"'^* In'd depths^

munication with the rest of the mine, and in with renjark*.

yfhiCh consequently tVjfive is no current of
air.

2. Here the thermometer immersed in a lit-
tle stat^nant water on the ground rose to .... S2'2^ 228* .6

3. I then ascended to the former gallery,
and under a strong infiltration, in the water,
and in a jjlace traversed by a cun-ent of air,

the thermometer iudicated 54*9^ 195, 10

I then directed my course to the south,
where the present workings are.

4. At the second gallery, at a little distance
from the main shaft, in a place where people
are continually passing, and where there was
a pretty Strong. current of air, a httle stagnant

vrater indicated .« 57.00 261

.5. At the iil'th gallery, the thermometer im-
mersed in a reservoir of water, which was near
^he main shaft, rose to 6v)'8° 457

6. At the extremity of the gallery, No. 9^,
the part where the works are farthest ad-
vanced in a southerly diiection, a large quan-
tity of water, slightly vitriolic, spouts from
the rock. The thermometer, kept a quarter
of an hour in the midst of this stream, con-
stantly marked 65*7° 750

7. Held on one side of it, in the open air, it
equally gave the sanje temperature ........ 65' 7° 750

8. Tt was the same about sixty paces to-
ward the shaft, when immersed in the middle
of the rivulet formed by the spring just men-
tioned 65*7*=' 750

The bottom of the mine was inundated, the
vater lying on it about 16 met. [52 feet] deep:
and by a small shaft, at a little distance from
the main shafts I descended to the level of this
subterranean lake.

9. The thermometer, kept a quarter of an

hour

154

Tabulated
temperatures
•nd depths,
with remarks.

ON SUBTERRANEAN HEAT.

1 1 1 rt .• 1 . ,. Tempo- Depth.

hour on a board tioatjiij^ on the water, mni- rauire.

776

77(J

cated *. Q4p

10. Immersed in the water it equally indi-
cated .....'.......' (J40

All the water that enters into this southern
part of the mine runs into the lake, from which
it is pumped up.

11. The temperature of the water issuing

from the pumps into the gallery No. 7 was • • 65*1® 587 ''G

Following the course of this gallery the wa-
ter runs to another shaft in the north part of
^e mine.

12. There it mixes with a small quantity of

V^ter, the temperature of which is • • « 57*2° 391 * •$

13. And when the water thus mixed is con-
veyed by the pumps to the discharging g^allery iiTO-> at:
it raises the thermometer to 63-3^ ti -rq v.

General de-
<!uctions.

Katu'aT tem-
jierature

agrees with the
Iheory. -

Increases with
4h3 depth.

Increased in
one part by
therm al wa-
ters.

Ca'.i?e of their

We have here two classes of observations to distinguish ;
those made in the north part of the mine, I, 2, 3, and 12;
and tliose made in the south part.

The first appear to me to indicate the natural tempera-
ture of the soil. No. 1, made 20 or 30 yards below the sur-
face of the ground over that part, of the mine, must be con^
sidered as giving the true degree of heat of the surface of
the earth in that country. I perceive no cause, that can
have altered the natural temperature of the place, which is;
very far from all the workhigs : certainly it continues the
same throughout all seasons : and its expression is precisely
the sam^ as theory indicates. Observations 2 and 3 sho\v„
that this temperature increases, as we penetrate deeper.
The current of air in the first galleiy, that through which
the ore is conveyed in wheel barrows, accounts for the smalj
excess of heat observed in it proportionally to. the depth.

As to the temperature of the observations made in the
south part of the mine, it is visibly influenced by a foreign
cause, the arrival of vitriolic wtiters coming from the south,
On sinking a new shaft a huridred yards from the southern
part of the present workings, strata of aluminous schist
were traversed, which had a very strong styptic taste as sqon

MURIATIC ACID BY GALVANISM. 1(\55

as '4xtradt^(!. "With a lens a iiumber of pyritous pioints may '*

be observed in it, which by their decomposition and action

on the schist probably produce an evolution of caloric, that

heats the water traversing these strata. These being at no

great depth may have a communication with the atmosphere _

through some fissures, and thus the decomposition may have o

been effected.

However this may be, it appears to me certain,' that the .

water must have acquired the heat of 20° [66-2 F.], which
is much more than naturally belongs to their depth, by tra-
versing these sti-ata.

I shall here observe too, that, if the heat is to be ascribed pyntes In co»!.
to the pyrites, they produce it by their action on the schist, junction with
Ifi the observations made at Poullaouen, we found a^onsi-
derable quantity of pyrites, without any particular heat
being produced : audi must repeat what I have said else-
where, that I have seen pyrites extracted, and found the Pyrites do tioI
heat not perctptibly greater than in other mines. Accord- always occa-
ingly I am inclined to believe, that pyrites in the mass, or
at least not radiated, do not prodnre subterranean h^at: but
such as are disseminated in extremely small parts through
bodies on which sulphuric acid is capable of acting are in a
different case, when the atmospheric air can have access to
them. In another paper I remarked, that the inflammable air Firedamp not

called fire-damp in coal-mines does not proceed from the coal Foc^uced by

. • 1 ^. 1 • 1 • 1 '^"^ most pyn-

that contams most pyntes, but from that m which scarcely touscoal.

any is discernible, and where the sulphuret of iron is proba-
bly in imperceptible particles.

XIX.

Letter from Dr. Veau-de-Launay to J, C. Delametherie,
on the Production of oxigejiized muriatic Acid by the gal-
vanic Pile*.

JL FIE experiments with respect to the production of the ^^j^ obtained
pxigenized muriatic acid, obtained in distilled water by the by galvanism

* Journal de Physique, Vol. LXllI, p. 472, Dec. 1806.

galvanic

156 SCIENTIFIC NEWS.

in small quan- galvanic action, have hitherto exhibited but a small quantity
titles hitherto, ^j- ^^.jj . which has led persons to question, and even to deny,
the result^f these experiments. What has lately been done
by the experimental clubs of the Galvanic Society will leave
l|or. of water no doubt with regard to the product. Fifty, grammes, or
converted into jj^arlv an ounce and half of distilled water, have passed into
riatic acid, dis- the state of oxigenized muriatic acid^ and dissolved a gold
solved 27 in, yy^r^. ^f ^\^^. ientfth of about 0*07 of a metre, or 2k inches f 2 in.
p/ gold wire. ,. ^^ -, ^ i . , , • , ^ . , ,.

7 Imes JLng.j, immersed in the cylinder, containing the dis-
tilled water, which had acquired a very sensible and even
strong smell of that acid, as well as u yellow colour, such as a
solution of gold exhibits. To these diifefent characters, easy
to distinguish^ were added those of the action of different
Precipitated by i^agents. The tincture of litmus was reddened powerfully ;
^e,.^ the solution of nitrate of silver was speedily changeti, and a

precipitate of muriate of silver thrown down.

I can assure you, there is not the least doubt of the cer-
tainty of the results displayed by this conversion of distilled
water into oxigenized muriatic acid.
If the acid Even if the result oi the experiment were to be consi-

were extricated dered as an extrication of the muriatic acid from the solu-

from the salt . p , • i • i t i

merely, still tion oi salt contained in the cylinder of the copper pole, a

interesting. very interesting phenomenon would remain to be considered
in this product. This experiment therefore deserves parti-
cular attention ; and it is to be wished, that it was varied
and repeated in different ways. I doubt not but the result
will offer facts of considerable importance to the science of
natural philosophy.

SCIENTIFIC NEWS.

New Bavarian -^ HE Bavarian Academy of Sciences at Munich, nc-o
Academy of cording to its new constitution, is to have a more extensive
field for its labours than any other in Europe. Under the
^ direction of the ministiy, it is to have the immediate super-

intendance of all the public seminaries of education in Ba-
varia, from-the universities down to the primary schools. It
will be composed of learned natives, and foreigners of cele-
brity invited by the government from other parts of Ger-
many.

SeiENTIFIC ilEW?. 157

many. Privy counsellor Jacobi is still tallied of as its prN ^

sident. Among the other academicians, whose names have
been mentioned, are Mr. Seyffer, whom the emperOr Napo-
leon appointed engineer geographer in the war against Rus-
sia and Austria, and who has been director of the observa-^ ^
tbry at Gottingen ; Eichhorn, the historian and orientalist,
whom the king^has likewise called from Gottingen ; Wiebe-
king, of Vienna, whose skill in hydraulics has already been
of service to the kingdom ; and Wolf, known by a very good
history of the Jesuits, to whom all the archives of Bavaria
are opened, for the purpose of his compiling a national his-
tory.

The royal library, which is already a very good one, will l^oyal library
be increased by a committee appointed to select for it every
thing of value in the libraries that are suppressed.

The collection of paintings at Munich has long been ce- Collection of
lebrated; but, -since the galleries of Manheim and Dussel- ^ ^ *'^*
dorf have been added to it, it is unquestionably the finest
in Europe, next to the Napoleon Museum.

A decree has been issued at Naples for forming 'a society Royal Acade-
consisting of forty men of letters, to be called the Royal &^AmruiU«
Academy of History and Antiquities. The first twenty at Naples,
members are to be named by the king; and when these have
assembled, they are to nominate three persons for each of
the remaining vacancies, out of whom the king will choose
one to fill it. It is to have a perpetual secretary appointed
by the king, and to choose its own president for three
months. The directors of the museum, excavations, and
royal printing office, are always to be chosen from its mem-
bersi The academicians are to be admitted at court.

Mr. John Maeltz, of Vienna, has exhibited at Paris a Mechanical
musical machine of his invention, to which he has ariven the ^'"i^^tion of
name of panharmomcon, 1 his machme, moved entirely by instruments
springs, gives the sounds of vairious wind instruments with ^"^ others.
a clearness and perfection never before attained. The in-
struments that compose it are the gerrnan flute, flagelet,
clarinet, hautboy, bassoon, horn, trombone, serpent, and
trumpet ; beside kettle drums, a great drum, cymbals, a
triangle, &c. Pieces are performed by it with great preci-
sion, and the forte and piano distinctly marked. The exe-

cutioa

15B SCIENTIFIC NEWS.

cution df the tfumpet isiparticulrtiiy astonishing. For eacit
instrument the inventor has contrived a moulhpiece adapted
to its nature, which answers with the greaiest perfection to
the capacity of the human organs.
Intended tour The chev. von Hoegemuller, superinteiidant of the Aos*
iuthe Last. ^^^^ ^^lilitaty studs, i& to set off in November (vn a tour in
the East, with the necessary instrumeiits and attendants,
under the patronage of prince Charles. His principal oL)-
ject is the natural histor\' of the horse ; but he will n>uke a
point of endeavouring to answer any quesiious, that shall
be addressed to him by the learned who cultivate sieogra-
phy, p])ilo!ogT, archaeology, numismatics, &c. He intends'
to traverse Hungary, Transylvania, Buchowina, the Ukraine,
embark at Odessa for Constantinople, and thence proceed'
to Aleppo.
Ancient busts Mr. Jefferson, the president of the United States of Ame-
Scan ladumsr ^'*^''*' ^^^^ "^ possession several busts made by Indians. They
are nearly of the natural s ze, and reach to the middle of the
body. The features are well marked, and characteristic of
the copper^coloured or American race. In one, represent-
ing an aged savage, the wrinkles and the expression of the
coimtenance are very well marked. These busts were found
in digging at Palmyra, on the river Tennessee. The sub--
stance of which they are formed, and which is extremely-
hard, is not known: some suppose them to have been cut
by the chissel out of solid stone ; others that they are a com-
position, first moulded, and then burned. Whether they
were idols, or busts of distinguished persons, is equally
questioned. Who were the progenitors of the present race
of Indians, that were capable of thus executing a tolerably
good resemblance of the human head, face, neck, and shoul-
ders?
Extensive General David Memweather writes to Dr* Mitchill p£

ridges of shells i^fg^ York, that the vast bauks of shells commencing on.
the southern bank of the Savannah, near White Blutl, ex-
tend in a right line through a space of about a hundred
miles from the borders of the sea toward the sotith-w est;
The ridges are not entire, but the ground is rnqre. elevated
to the breadth of six or eight miles than it is above or be-
^gw. Not only oyst-er-shclls, but those of cockles, and others,

are

SCIENTIFIC NEWS. loj

are found. Some are entire, and very large : others are ag-

j>Uitinated as by a cement. Some are iaige enough to cpa-

tuiia a man's foot. In different parts of the emiaences for

forty miles some of these sliells occur. They are used ror

makiijg hme ;. but a Uttle hi^her up to the south-west there

a heap of shells forming a kind of rock, that is preferred

-1 this purpose. At some distance still higher, and in the Fossil shells in

same direction, there are several quarries of a kind of sili- *

ceous stone, in which a great number of shells of all kinds

are interspersed here and there. These are petrified, and ^^^^ ^^ ^"^**

as hard as the flint itself. Millstones are made of it, in qua-^^^ljsto^es
1- ,1 , n TT made of it.

lity nearly the same as those or r ranee.

At Hudson's Bay some experiments have been made with Quicksilver ■
frozen mercury. It was reduced to a plate as thin as paper, ^^^^j^ plate,
by beating it on an anvil with a hammer brought to the same
temperature as the mercury. A piece of it being thrown
into a glass of hot water, the water froze instantly, the glass
flew to pieces, and the mercury became fluid.

Dr. Bacoaio 'of Milan has lately composed a galvanic
pile entirely of vegetable substances. He forms it of disks
of red beet root, two inches in diameter ; and disks of wal-
nut tree, of the, same size, divested of their resinous princi-
ple by digestion in a solution of cream of tartar in vinegar.
With this pile he produces galvanic efl'ects on a frog, taking
a leaf of scurvy-grass for an exciter.

THE seventh number of the new series of the Mathe- J;^atl^ematicaJ

Kepository,
matical Repository, by Mr, Thomas Ley bourn, contains :

1. Solutions to thirty curious mathematical questions pro-
posed in a former number; 2. Solutions to some mechanical
problems by Mr. John Dawson; 3. Solution of a curious
diophantine prob*jem by Mr. Cunliflc ; 4. An essay on the
theory of amicable numbers by Mr. JohnGough; 5. An
investigation of some theorems for finding the sums of cer-
tain infinite series b}^ Mr. Cunliffe: 6, Le Gendre on elliptic
transcendentals : and 7. Thirty new questions to be an-
swered io a subsequent number.

Mr.

l^Q SCIENTIFIC NEWS.

Newmitieralo- Mr» ACCUM, to whom the public is indebted for a Sys-
liica wor . ^gj^ ^^f practical Chemistry and several otlier works, has pnt
to the press a System of Mineraloj^^y and Mineral o«i,"ical'
Chemistry, and its application to the arts. This work, which
is formed chiefly on the plans of Haijy and Erongniait, will^
be in 2 vols. 8vo. with eight copper[)lates.

Sargical and
pbysiological
lectures.

Medical and
chemical lec-
tures.

Lectures on Surgery, and on Physiology,

Mr. A. CARLISLE, F. R. S, F. L. S. and surgeon tc/
the Westminster Hospital; will begin his course of lectures^
on .the art and practice of surgery, in all its branches, on
Tuesday, October 6th*, at eight o'clock, P. M. at his housfe
in Soho Square. The subject will be continued on Tues-
days, Thursdays, and Saturdays, at the same hoar. The
diseases and accidents allotted to tfie province of surgery
tvill be fully treated of, and illustrated by cases from the
lecturer's experience. The diiferent operations will be de-
monstrated, and the anatomy of the parts explained. On
ttie same evenings, a course of lectui'^s will be delivered on
the natural history, physiology, and pathology of the human
body, calculated to illustrate the several processes of heal-
ing, and to afford a; compendious *iew of the animal econo-
my. The introductory discourse will be open to all stu-
dents.

Medical and Chemical Lectures, St. George's Hospital, and
George Street, Hanover Square.

ON Monday, October 5th, a c6urse of lectures on phy-
sic and chemistry \^ill recommence at No. 9, George Street,
Hanover Square, at the usual morning hours : viz. the me-
dical lectures at 8, and the chemical at 9 o'Clock. By
Ge6rge Pearson, M. D. F. R. S. senior physician of St.
George's Hospital, of the College of Physicians, &c.

Note, a register is kept of the cases of Dr. Pearson's
patients in St. George's Hospital, and an account is given
of them at a chemical lecture every Saturday morning at g
o'clock. Proposals may be had at the Hospital, and at
No. 9, George Street,

.A

JOURNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

NOVEMBER, 1807^.

ARTICLE L

Facts toward a Hhtonj of PitcoaU ty Professor ProuSt^

A

: Coal of Decise, distilled by Siige, left '59 or -60 of Coal left from
carbonaceous residuum, or coak. A coal of Cevenes yield- ^^^ '^'^ "^
^<i BerthoUet •76 or *77 ; and that of a pit in the forest of
Gensane '75. T obtained from a coal from England '64 :
from Lieres 'Co, and froni Fondon, both in Asturia, '64:
from Belraez, in Estremadura, ^Q5 : franl Villa Nueva near
Seville 'SS: from Quiros '70, las Carnaras '70, Langreo '75,
la Kionda '76, and la lliosa •77> all in Asturia.

The environs of Madrid exhibit a few Vestiges of earth No coal near
impregnated with bitumen, but no coal, as was hoped; for " ^ " *
there is not a city in Europe at present ^o mudh in want of where it is
it. I hdve visited nO coal pits in Spaih, but some of those "^^ch wanted.
of the fertile and picturesque province of Asturia; a coun-
try that exhibits in miniature whatever of grand and sublime
the traveller admires in the Alps. The coal there in gene-
ral is in veins of little thickness; scarcely any so much as 18
inches.

The follow ing were the products of a hAindred poun(is o*f -
some of the coals I examined.

♦ Abridged frrtm Journal de Physique, vol. LXIII, p. S.20, Oct. 180G.

Vol. XVII I— Nov. I8O7. 78. M ViUanueva

162

BISTORf OF PITCOAL.

Products of dif-
ferent coals.

General con-
clusions.

« Coak» OiL

tbs. oz. dr. lbs. oz.

Viilanueva ''Gs 8 4'» 7 9

Belmez 70 0 2- -10 4

Langreo •..•75 0 0"1] 11

English ....64 1 0-. 7 0

Wafer,

dr.
0.

0-
4-
4.

Ib^.
4

7 7

4 7

12 14

Gasses lost*

lbs. oz, dr.
5 ()

7 4
3 2
t) 2

19

12

8

16

Tliose which
yield most tar
not easiest to
distil.

From these observations it follows, that the oily product
is more abundant than the aqueous froni three of these
coals.

2. Tliat the weight of the gasses is as variable as that of
the liquid.

a. That the veal quantity of coal furnished by these bi-
tuminous substances is in general above '60, and less thain
•80.

4. That it is three tiilies as riluch &s wood affords : atid we
know nothing but indigo, that can be compared with pitcoal
ID this respect.

5. That the matter of pitcoal varies as much in its car-
bonaceous, oily, gaseous, and other products, as the organ-*'
ized bodies, that are formed at present before our eyes.

6. That its oily produce is in general much greater, than
our resinous woods, as the oak, elm, ash, &c., can furnish.

7. That pitcoal is thrice as serviceable, in furnaces that
admit its use, as any wood known, since it leaves thrice as
much coally matter.

8. That its coak, in consequence of its azotization, de-
rives from our atmosphere much more tire thaa charred wood,
since it cannot burn but by decomposing a much larger
quantity of oxigen,

9. That as tlie oily and gaseous products are formed as
well in the open air as in close vessels, some coals produce
more flame than others, and are consequently better adapt-
ed to furnaces where a considerable current of flame is re-
quired; as those of bronze, porcelain, earthenware, &c.

10. That those which leave most coak after distillation
^ill consequently last longer in iron works, reverberatorj
furnaces, &c.

Of these four coals perhaps the richest in oil would not
be the most easy to distil, at least by lord Dundonald s me-
thod, since they run, swell up, and agglutinate, so as to-
ward

Ht'sTOliY OF PiTCOAL. 153

ward the end to become a uniform mass, no#to be divided
without labour.

All pitcoals iii general <^ive out more cr less sulphurous Yield sulphur-
acid toward the end of their combustion, which is owing^ to ^"^ acid,
pyrites. At first I supposed, that they contained a peculiar
compound of sulphur and carbon ; but all that I passed
through nitric acid, to free them from pyrites^ burned to
the end without emitting the slightest smell of sulphurous
acid.

The oily product of these coals varies greatly in consist- Oily product
ience; it is more or less fluid, and a direci experiment is al- si^tence" '^^^^
ways necessary, to ascertain how much thick oil, or tar, it
will afford. Is this tar really more preservative, ^.nd better Should be far-
adapted to retard the spontaneous oxidation of cordage, and ^^^er examined,
the rigging df ships, than that of resinous wood? This has
been asserted, but should it not be farther examined ?

The light oil separated from it is succinated, and not lin- Light oil,
pleasant. It is readily turned brown by the air. No parti-
cular use for it is known.

The aqueous product c6ntair<s carbonate df ammonia, but Water contains

in small quantity. I did not find in it any vinegar, but I carbonate of

T •' ^ , , -^ . ammonia, and

could wish to Examine this again ; particularly as I find in succinic acid.

my notes, that I separated a little succinic acid from it by

treating it with the muriatic.

The gas is an oily hidrogen, that burns with a white flame. Gas, oily'hi-

^hich limewater diminishes very little, because the ammi)nia[ fi'oge", with

. . , verv little car-

retains almost all the carbonic acid. bonic acid.

Naturalists, reflecting on the similitudes that analysis per- Coal supposed

ceives between the composition of ve^retables and that of *,*^^^ P*"*^^^^^*^

, . 1, 1 1 It ffO'^'^ vegeta-

pitcoal, have pretty generally supposed, that coal may have bles.

been produced by heaps of fern, polypody, reeds, jind aqua-
tic plants destroyed, the impressions of which are retained
by the adjacent strata ; or even by trees, and their frag-
luents, such as those which certain rivers by their inunda-
tions sweep away from the earth ; and that the sea has bro-
ken them by its agitation, and accumulated them in the
basins, fr«m which we at present extract them. Etit the
mechanism, and even possibility of these operations, simple
as they are in appearance, are exposed to innumerable diflfi-
culties, when we examine them in detaiU

M 2 IFor

164 HiiJTORY or PITCOAL.

Objection? to For mst-anc^l the most elevated parts of the Globe on
sis.* ^° which depositions of coal have been found, as the Cordillera

in Pern, where Leblond met with them, beiniij more than
fonr thousand yards above the level of the sea, do not easily
bend to the explanation attempted, when it is alleged, that
they are forests or plants swept away and comminuted by the
waters. IJad the sea at that period no lower place, on which
to deposit its rand of broken plants? or was the Cordillera
itself very favourable to the production of vegetables? These
objections, which were made by Patrin, are not easy to re-
move. If we consider farther, that these immense tracts of
carbonaceous mud, which resemble torrents of melted resin
that a volcano his vomited out at once into valleys ten, fif-
tc€in, or twenty leagues long, and to the height of thirty,
forty, or sixty feet, exhibit not the slightest interruption,
not the least vestige of fishes, shells, bones, or stones, in
their beds ; no foreign body in their mass; to indicate those
convulsions, or that diso.der, which the imaginution cannot
easily separate from such great devastations of forests, moun-
tains, and continents : we must confess, that such produc-
tions are not explicable by some of those accidents, of which
nature at present gives us occasionally examples.
Alternation of Beside tljat tlie recurrence of fifty or sixty strata of coal,

trmr strata ^j^jj ^ many of sandstone, do not allow the mind to con-
wuh vaitdstoue. . -' i • i V i- ^ -,

ceive, how these two kinns or seumient can have been accu-
mulated exclusively ; as if previous to these periods the earth
could produce nothing, but what furnished the sea with trees
to pulverize, and silex to precipitate, alternately ; and nei-
ther beast, nor bir<f„ nor rock, nor flint, nor gravel, to dis-
turb their contiiiuity : we must likewise observe, that the
coal, as we now find it, has certain characters, that will pre-
sently be r sntioned, which perhaps place it at a greater dis-
tan<*e from vegetable than from animal substances.
Impressio;><; of What data then have we after all for ascribing to plant*
plants in the ^y^^ orii^ln of bitumens? a few traces of mosses or ferns,
surrounding i . i p , i •

schist only scattered through the leaves of slate, that serve as their en-

proire, that velope ? ' Such vestip'cs ])rove at most, that nature, durincf
sr.oit then ex- , •..>,, ^ ' ,• ri • a ^ ^

iatitil: the period oi these great operations, likewise made plants

grow, and nourished animals in the seas, since we find shells

in the strata that separate the coal in some countries ; but

not

HISTORY OF PITCOAL. iGS

not tl+at It reaped from those plants sufficient materials to
till those inexhaustible lakes of bitumen, that intersperse
our ^lobe from one pole to the other, and which the genera-
tions vet to be born will perhaps never exhaust. Thev ^'^.'■^.^^'^*/"^^

' ^ . ., ongiuutcd on

would |>rove too, if this could be doubted, that it did not jij^ surface of
fabricate this composition, as it does that of minerals, mihe Earth,
the interior of the earth, but on its surface only ; that is,
in the region it has chosen for the existence of organized
beings.

It is true, that trunks of trees are found in veins of coal : Trunks of trees
consequently trees existed at that period. But are these jj^^^, really
trunks themselves coal ? Have they been analysed with a coal?
view to compare their products, and examine whether simi-
lar changes have taken place in these trees, and in those
that are supposed to have been converted into coal ? The Analysis of

importance of analysiui^ fossil wood in this respect appears dossil woodim-
, • r<. . 1 11 1* -1^. 1 portaat to the

obvious. It It were once demonstrated, that a tossil trunk qucbtion.

of a tree contains charcoal in the same proportion as the bi-
tumens surrounding it; and that this charcoal, beside its
degree of concentration, is combined with a fresh dose of
uitix)gen, so as to have lost that prompt and easy combusti-
bility, which characterizes the charcoal of our woods ; we
might flatter ourselves, that we had an argum.ent of great
weight in favour of the opinion here attempted to be shaken :
and we should be less surprised to find in this astonishing
result of their metamorphosis, pitcoal, seventy or eighty Quantity of
per cent of cliarcoal ; that is to say a proportion, which, if charcoal m pit-
• 1 1 1 PI • • 1 p ^^'^' incoasis-

it had been that of the vegetables existing before those pe- teni with such

riods, would appear difficult to reconcfte with that elastic ^'^?^'^^^'^^ ^'^

. . . . . ours.

and robust organization, which our forest trees require, to

raise tirm and secure trunk, and resists the storms of an
atmosphere agitated like ours. This weak part of the grand
problem may sooij be elucidated, if our cabinets do not de-
lay the eagerness of chemistry to decipher the medals of this
kind they contain : and if natural history, assisted by thp
light of analysis, do not discover something more satisfac-
tory, than any thing that has yet been advanced respecting
the origin of pitcoal, we ought no longer to waste our time
in reasoning on this prodigious event in geology, but banish
ail tjje hsarned hypotheses that have been started o a the sub-
ject,

l66 HISTORY OF PITCOAL.

ject, in CQiisort with those romances concerning the origiu

of metullic veins, to which our age has given birth.

Coal as nnich J ],ave said, that analysis discovers in these bitumens cha-

resenibles an ''

animal as a ve- racters, that do not show a greater affinity to vegetables

getable pro- than to animals. The following are the facts : and 1 leave

it to the learned to decide which way the balance inclines.

Its smell not J, Thp ^mell that coals exhale when heated is avomatic,

■wood bu° succin^ted, and decidedly resinous: it irritates neither the

fricndjy to the eyes nor the lungs, like that of wood or vegetables when burn-

"^^s- ej. and this resinousr smell has ev^n been considered as

friendly to the diseases of the chest.
Softens and 2. All coals soften, Icjse their shape, run, mould them-

by^heat?^ ^^ selves to the shape of the retort, and fill it with a spongy or
puffy coal, like that common to mucous substances, resins,
indigo, gluten, and animal matters; ]3ut npt like that of any
known wood or- plant.
Yields more oil ^. Distillation obtains from it a lighter, more aromatic,
ammonia, ^^^ niore abundi^nt oil, than the nonresinous woods used fo^r
but no vinegar, fuel; and 4 great deal of water and ammonia, but none of
that vinegar, which abounds in the distillation of our vege-
tables ; that encipyreumatic acid, which reriders thpir smoke
so troublesome and suffocating; vinegar whic'h is formed,
whenever oxigen is an integrant part of ap organic oxide,
and the absence of which in the products of coal would au-
thprise us in a certain degree to doubt, that oxigen is one of
its products*.
Coak does not 4, The combustipn of coak does npt at all resemble that
?eTwood •''^'''' ^^ ^^^ vegetable charcoals.. It is slow and difficult like t\m%
of mineral coals, because it likewise contains condensed ni^
trogen ; accordingly it requires a condensed atmosphere to
burn it. *'

affords prussic 5, Coak passed through potash always affords a prussic

' lixivium, which vegetable charcoals in general do not.
cannot be set 6. Animal charcoal cannot be set on tire by nitric aci(|,
on fire by mtric ^y^^ after it is disazotizf d by potash : neither can coak, everi
passed through this alkali.

Pyroliirneous * ^ f^"" some time doubted the fact, that the pyroligneous acid wac

acid formsace- really vinegary but J am now convinced of it, as the sail I formed with
ttite of copper, pxlde of copper and the acid of elm displayed is characters after three

purifications. It gave larsje rhombs^^ difxeriug in no respect from acetate

of copper.

A ri|ixture

HISTORY OF PITCOAL. l67

A inixtLire of nitre and coak burns with the same diffi- and mixed
jcalty as mixtures of nitre and charcoal of blood, white <>f bums difficult-
egg, indigo, &c. ^Y
' 7. There are few kinds of wood, that do not leave more Coal leaves
ashes than pitcoal. Coal therefore Is not clay impregnated ^J'^^f ^.^^1?^?
with bitumen, ais some naturalists have thought. fore not day

I have not yet found any oxide of manganese in animal "y,'^^^^^^^^^^ '^^"
charcoal; and I have sought it equally in vain in the five j^^ ^,^.j^ ^^
kinds of coal mentioned above, manganese.

8. Vegetable ashes contain a great deal of carbonate of Ashes ofvege-
lime, beside magnesia, alumine, and silex. Those of the f^^^m^holrof
five coals I examined afforded me t)nly a great deal of silex, coaL
a little magnesia, alumine, and sulphate of lime, but very
little carbonate; and in particular not an atom of those salts,
jyhich are habitually contained in our vegetable ashes;' no
phosphate, no muriate of soda, though the mud of these bi-
tumens is supposed to have been formed with sea-water.

10. All the soft or liquid parts of animals contain sulphur. Contains tul-
They cannot be dissolved in potash, without having the so- "
lution loaded with :t. Wool cannot be dipped in a bath of
litharge and lime without being blnckened, in consequence
of the sulphuret of lead that adheres to it.

If no pitcoal be absolutely free from pyrites, is it not be- Nonefreefitom
cause Ihe sulphur and iron, those two habitual elements of P>"^^^"*
animal matters, have withdrawn from the organic substance
converted into bitumen, to form a separate combination?

I content myself with bringing together these facts, and
refrain from dt ducing any consequences from them, as they
require to be compared with a greater number of coals, that
it may be known whether they be as general as I suppose.
But we now come to other properties, which sepa- ate still Farther differ
more the analogies supposed to exist between pitcoal and ve- *^"'^^^*
getables. ^

If, for exaiTiple, the carbonaceous principle be an ele- Charcoal fee-
pient of their composition, in the same manner, and in the !^' ^^nibine
same sense, as it is in our vegeta'^es and animals, we shall
chow, that it is very feebly combined however, verj- weakly
enchained at least by the hidrogen, nitrogen, and oxigen: I
could almost veniure to say independant of them, since it
may be ex.tracted from pitcoal by means, that certainly would

never

168

HtSTORY OF PITCOAL.

Coal treated
witli nitric
acid.

reduced to
coak.

This not the

The same as
produced in
distillation.

Hence the

never succeed with any vegetable or animal production we
know.

Let powdered coal, such as that of Villanucva, wliich af-
fords 68 per cent of coak, be heated in nitric acid of 18° or
20®; and thus in a few moments it will be- deprived of the
property it had before of forming' oil, oily gas, and ammo-
nia. The coal thus prepared, washed, and dried, and then
exposed to a moderate heat, affords products of a new order,
but with indications of those just mentioned, and is reduced
to '66 or *67 of coak.

All pitcoals afford this extraordinary result, which is ob-

case even with tained from no organic production known, not even from in-
incugo. . . .

digo, though it contains '7- or '73 of charcoal, or much more

than many kinds of pitcoal.

The carbonaceous principle, freed from the other ele-
ments of the compound by this method, has all the proper^
ties of what would be obtained by the simple distiHation of
pitcoal ; for, if it be treated with potash, it gives a prussic
lixivium like coak itself. I proceed to the conse((uences.

If in these bitumens the carbonaceous part be thus feebly

blackness and enchained by the other elements, and consequently approach
brittleness of . . ' . . . , • i i "^ ,

coal. in its properties charcoal uncombmed, we need not be sur-

prised either at the blackness or fragility of pitcoal.
The charcoal The Carbonaceous principle of organized bodies, freed

m coal retains fj^Q^ ^\^q fetters of combination by any means, and conse-
gome hidrogen , ^ ■, - '

and nitrogen, quently brought nearly to its natural density, may not sepa-
rate totally from the hidrogen and nitrogen, in consequence
of the reciprocal affinity of these three combustibles ; as is
shown by the habitual state of the coal in our fires, which
always contains more or less of them : but the same cannot
but no ox-gen. be said of the oxigen. The condensation of the charcoal,
carried to the degree that makes it appear black, is a state
decidedly opposing the capacity of this principle to adhere
to it as easily as the oihers. This admitted, if the charcoal
in these bitumens be near its habitual density, we must not
be surprised, that, remaining still united with the nitrogen
and hidrogen, it cannot be equally so with the oxigen. On
this principle neither is it strange toUnd, that pitcoal does
liot contain oxigen in a state to concur, during its distilla-

- tioiii

HISTORY OF PITCOAL. 16^

tioii, in the formation of vinegar; as it does, when it is a
constituent pact of our vegetables.

But lastly, if nitric acid separate from these bitumens a ^^^i^^^J^'^fhe-"
charcoal united with nitrogen, such as distillation would micaily cora-»
furnish, it uiu«t be acknowledged, that coak exists free and bined,
condensed in their constitution; but not in that state of per-
fect combination, or mutual interlacement, which never fails
to efface the characters of the elements of organized sub-
stances, as they reciprocally mask each other.

I have said enough. I beheve to show, that pitcoal, if it ^oal '-etain*

^ . . * noth n«^ of the

consist of vegetables, has retained nothing of the characters, veg^itable ch*-

that would approximate it rather to vegetable than animal '■=^'^^^'"'
substances. Vegetables, animals, bitumens, all have the
same elements; tliat is nitrogen, hidrogen, oxigen, charcoal,
sulphur, &c. : but the combination of these elements in pit-
coal certainly does not in any respect resemble those, that
vitality now forms in the beings arising before our eyes.
Where in fact are the vegetables or animals, that contain
charcoal simply deposited in their texture, as an oil or resin
is in a plant .^ Besides, what organization could admit with-
out inconvenience such a considerable excess of charcoal as
that we see unemployed in these bitumens? Such a prof u-
eion certainly could only be an oversight of nature.

We must therefore stop at one or other of the following Eitlier there
consequences. Either nature was once capable of producing "^'^"^* '^^'''*^ , .

*■ . . . I r o been organized

beings, the organization of which could admit so large a beings difFer-

proportion of charcoal ; and then the life, object, end, and ^'^* ^'■^^rn the

means of existence of such beings, could in no respect be

compared with those that now share the surface of the earth

^'ith us ; and on this supposition pitcoal could only be the

remains of animals or vegetables, which like so many others

have disappeared from it for ever :

Or, if coal have originated from organic productions si- or their ele-

iiiilar to ours, its interment has not only destroyed all marks ["^"^^^ ^^^^

^ '' '' have been

pi organization, but has displaced their elements, to reframe separated, and

them, and fabricate with them tiiose fossil masses, which ^'^'"^"'-^ '" *

. . ... . difft-rent way,

have indeed retained all the combustibility of their nature, to form coa,)'.
but in which we discern no trace of vegetation or animaliza-
tion, no indication of the part they had to perform on the
jsurface of the earth.

Oxide

iro

HISTORY OF PITCOAt.

Charcoal unites
•with oxigcn to
form an oxide.

Coal tieate4
^vith nitric
acid,

gains an in-
crease.

This owing to
a real coajbi-
jiation.

Oxide of char-
coal, heated,
in a retort.

detonates ob-
scurely.

Oxide of Charcoal.

Charcoal and oxig-en are susceptible of a kind of union,
whicli does not appear to me to have been noticed. It
is totally diiierent from carbonic acid, and from gaseous
pxide of carbon. These always take place between carbon
and oxigen; but the other readily admits chai-coal, whether
azotized or not ; such indeed as we burn. The following are
the facts.

A hundred parts of coal of Villanueva,' the coak of which
amounts cp Ob, y^e increased by the application of nitric
acid at 18° or 20° to 120 or 121 parts. Hence it follows,
that, if this acid destroy by ovulation all the principles
contained in this bitumen between o;* and 80, it leaves in
their place first 32, and next 20, of" sotiie other principle,
the nature of which we shall §oon perceive.

The coal of i3elmez likewise yields 120 or 121 ; that of
Langreo the same; and the English, which leaves 64 of coakj
proctuces 1 16, which amount to nearly the same.

That this is not owing to any thing merely imbibed, or to
defective washing of the product, is decisively proved by
the following experinient. Five drachms of Villanueva coal
became 6 by the application of nitric acid. These 6 drachms
were thrown into boiling water; but, after they had been
collected and dried, they returned precisely to the weight of
5 drachms. Such a result clearly shows a surcharge, which,
being of 50 Or 52, amounts to half the coal emploj^ed. It is
now time to make known its nature.

Hold in the hand a small retort containing one or two
hundred grains of oxided charcoal, its belly being at some
distance above a chatingdish, so as to receive a gentle heat,
and its beak being kept under water, to give vent to the at-
mospheric air, which the aqueous vapour t)egins to expel ;
and the instant the powder is agitated by a rapid movement
of ebullition, move the beak under an inverted jar tilled with
water. This movement, which raises up the charcoal brisk-
ly, is a strong' but obscure detonation, which terminates
quickly, and without the least danger. At the same time a
copious dew is produced, which, by its precipitation at, its

exit>

HISTORY OF PITGOAl. 17)^

exit, always canies some powdered charcoal out of the re-
tort.

> The srasses in this experiment are snch as miight easily be Fvolres car-
-> * . X 1 • -J J -1 „bonic' acid and

toreseen : a mixture or carbonic acid and gaseous oxide ot aaseous oxide,

carbon, burnini^ with a blue flame, and not detonating. If

it be yellow, it is owing to the charcoal having retained some

iiitric acid. This is perceived too by its reddening with oxi-

gen gas.

From the great quantity of water formed during this dis- ^uch water
tlllation, I was led at first to believe, that the oxigen of the
nitric acid, hidrogen, and charcoal, might form together a
sort of union comparable to that of a vegetable oxide, which
a higher temperature would occasion to be converted into
water, carbonic acid, and gaseous ojiide of carbon. Ailni
periiaps it is so. Yet the experiment I made immediately
witli powder of fir charcoal induced me, to consider the phe-
nomena as belonging exclusively to charcoal and oxigen.

Let nitric acid of 20® or 25° be boiled on calcined char- Wood charcoal
coal of fir, elm, or other wood, reduced to powder; the ^^.^^.*^^ ^'^^
pharcoal, after being washed and dried, will commonly have
a surcharge of twelve or thirteen per cent. If it be heated
with the precautions already given, it will detonate with agi-
tationj and afford the two gasses abovementioned, without
any mixture of nitrous gas. Other experiments will be seen
presently to prove, that this charcoal is in a state of pecu-
liar combination, and not contaminated by remains of nitric
acid.

I cannot fix with precision the method of thus oxiding This more va-
vegetable charcoal, because I have found it variable. But '^^'^^^^'
It is not the same with that of pitcoal, the state of extreme
division in which it is when deprived of hidrogen by the acid
facilitating that union, so as not to leave us to grope our
way.

Liquid potash, even at a boiling heat, has no action On Oxide of char-
pitcoal ; but if heated for a moment, in a very dilute state, coal soluble b/
on its oxide, or that of fir charcoal, a coffee coloured solu-
tion holding a considerable quantity is obtained, which is
not altered by standing, or by the addition of water.

Ammonia acts with equal efficacy on them. A hundred and by ammo-
grains of oxide of charcoal from Villaneuva coal dissolved "^^*

in

17S ttlSTORV OF PtTCOAL.

in it all except 15 grains, perhaps either because ihey were
not oxided, or because the oxigen had accumulated in the
rest, to facilitate its solution. From this solutiou an acid
threw down a precipitate, which was black and shining when
dry. It did not nnielt, and exhaled no smell on burning
coals.

Oxigenized muriatic acid precipitated it, without acting
on the precipitate.
Tlie solution, TJiis same charcoal, oxided, dissolved, and precipitated,
ySed sUe^< ^^'^ ^^^"^ burnt gray ashes, a little ferruginous, in which I
alamine, and found, silex, alumine, and a httle oxide. What sort of
*'^' union is there then between charcoals and their ashes? We

should suppose potash could not dissolve the latter. 1 ap-
plied nitric acid to difft^rent sorts of charcoal, to divest thera
of ashes, and try whether they would burn away entirely ;
but I could not succet^d.

I had intended to pursue the inquiry farther, but have

What so t of t>een prevented. TMeantime it will naturally be asked, what

combuiativ^n is (.Qj^Vj^f^^^^Qj^ qP Qjj^™gj^ ^j^jj charcoal is this, that excludes

neither nitrogen, nor any of the foreign substances it usually

contains ? and again what kind of union can charcoal form

with the same principle, without losing any thing of its den»-

eity or colour, which appears so little conformable to the

lavvd of combination ? I can only say, I know nothing on

the subject.

We Icnow less I would likewise ask, what is the nature of the combina-

c^ charcoal tiou that charcoal enters into with hidroo-en and nitrogen,
tflanoi carbon. . . ^ .

and other gasses which it absorbs and condenses in such

large quantity? In fact we are far from being as well acr

quainted with charcoal, which we see daily, as with carboq,

which never comes under tUe cognizance of our senses.

Duhidrogenized coal.

Coal divested When we consider how much the proportion of coak
of hidrogen. varies m pitcoals, we shall find it difficult not to believe, that,
if these bitumens be really derived from plants like ours, the
concentration of the carbonaceous principle, which is nothing
but the loss of hidrogen, must h;ive varied considerably in
different countries, A coal that yields '77 of coak cannot

contain

HISTORY OF PITCOAL* 1/3

contain as mucli hidrogen as another, that yields but '57
or 'Go,

This diminution of hidrogen has been carried so far in
some coals, that from a total loss of hidrogen they are pure
charcoal.

But if hidrogen have been capable of withdrawing entire- Nitrogen a<!-
ly from certain coally masses ; whicli will not appear sur- stmuV^^^ "***'*
prising : wlien we recollect, that the carbonaceous principle
in them is very near that degree of condensation which does
not admit combination ; it is not the same with nitrogen.
This appears to be the last of the movable principles to
quit it.

Near the monastery of Ilarbas, in the mountainous defile Natirc coak,
that separates the Asturias from the province of Leon, there
is a vein of coal, perfectly resembling that of Quiros in its
foliated texture and shining blackness. In this the carbo-
naceous principle is '03, while the hidrogen is absolutely 0.
In fact it is a true native coak, that burns without any bitu-
minous or sulphurous smell, and leaves '0/ of white ashes.

If, notwithstundiiig all its characters combined, it can be S.iU«mtejii»
supposed, that this was never the base of a bitumen, I ^"'•^^^^^
would urge the following experiment. Let it be heated with
potash, and prussic lixivium will be obtained from it. I'he
nitrogen, though the sole remain of the principles that bave
disappeared, here assists the chemist to trace its origin. It
iiicontestably indicates, that it has belonged to that organic
matter, which the hand of time has decomposed, to reduce
to pitcoah ^

Jet,

It is said that trunks of tret^ are found in collections, Trunk? ©ftr«««
ene extremity of which is converted into iet, while tlie otiier ^'^^^ j^h fe*i^
is still ligneous. If it be so, the analysis of such specimens
would be exremely interesting.

There is a great deal of difference in jets. A jet from /at? difl^f,
Almagra in Murcia gave '46 of charcoal without even soft-
ening: anothiifr, wrought into buttons, i^iielted like a re.si«,
and yielded ',52.

The following resultii to a certain point assimilate jet v^th
<?ur vegetables.

l74 • HtSTORY OF pfxcOAL.

Its resemblance Heat it with an acid at 20^, immediately a bulky efTer-
▼ege e». ygg^jgn^.^ takes place. As the solution advai.ces, a deep yel-
low or amiotta coloured concretion forms. The ebullitioii
should be continued a little while, to collect all that can be
formed. This substance, which is sbft while the liquor iif
hot, is easily softened jmd separated. On washing it in
boihng water, this acquires a yellow colour, hut does not
dissolve it. When dry it is bulky, bitter, and soluble in
alcohol. But what is remarkable is its property of deto-
tiating obscurely with a very moderate heat like oxide of
charcoal, either iti a retort, or held over the ilame of a can-
dle on paper,
i^foclucts. Its products are water, a little oil, ammonia, carbonic

acid gas, ^seous oxide of carbon buvninj^ with a blue Hame;
and '40 of a coal rridre bulky than the original substance.

The liquor that remains after its separation is of a deep
yellow, and very bitter. It yields crystallized oxalic acidy
and benzoic acid.
Compared Pitcoal heated with an acid of 40° dissolves slowly, doe*

^ith coal. not aiford any charcoal, and yields the detonating substance,
but with more difficulty, and in less quantity, than jetj
Cannel coal comports itself like common coal, and not like
jet. Some jet however does not yield the detonating sub^
stance without an acid of 40^, 6r with as much difficulty as
pitcoal.
Hidrof»en not ^^ ^^ consider, that the first action of nitric acid on pit-
fiecessary to coal consists in destroying the hidrogen, we shdl easily con-
•lurco'al^ " ceive, that this hidvogen is not necessary to the formation or
the detonating substance. The following experiment evi-
dently shows this. Oxided yillanueva cpal, certainly con-
tains no hidrogen : yet, treated with an acid of 40°, it af-
fords the detonating substance ; and since this yields water,
ammonia, oil, &c., it is evident, that the nitroo:en, the oxi-
gen of the nitric acid, and the charcoal which the water is
capable of furnishing by the concurrence of affinities that
bring on its decomposition, establish theniselves in a fixed
Illustrates the proportion, to give rise to tliis singular product. A vegeto-

formation of aj^inf^a] compound, an artificial oxide of this nature, remove*
tumun. ^ . . p .

the difficulties I at first found in the formation of tannm

from the simple presence of nitric acid and charcoal.

Acid.

lilSTORV OF PltCOAt^ ifS

Acid of 35° or 40®, heated with fir or elm charcoal, at Nitric aciddisl-
first i^ives out the gasses, that might be expected: but at a ^olves char-
certain point the gasses cease to be formed, and the char-
fcoal enters into solution. I have very old solutions of this
kind, that are h(it altered. Alkalies precipitate nothing
from them, because charcoal, either oxided or in a state of
simple division, is as soluble in alkalis as in acids. I had
proceeded thus far, when I learned from the Chemical An^
nals, that tannin was formed by the soliition of carbonaceous
substances. I believe Crell is the first, who announced the
solution of charcoal in nitric acid.

A hundred grains of Villanueva coal, ^reated with concen- ^?^}- treated ^^
trated sulphuric acid, and perfectly washed and dried, left acid.
104. Was this coal oxided ? T find nothing mentioned in
my notes, but that it burned withotit any bituminous smelly
that of sulphur only being noticeable.

Turf,

A Piece of turf froiri Dax afforded me the following re- Tuif

suits.

A hundred parts left 40 of charcoal without any change yields -40 of

of bulk. Its products were water, and vinejrar mingled c^^""^?^'' '^^'
. f» 1 • t • . t^r, vinegar,

v/ith ammonia, the taste of which did not differ from that of ammonia,

wood : but a yellow oily vapour came over, that became hard and '6 of a se-

like suet, which does not commonly occur in the distillation baceous oil,

of wood. This suet was from 6 to 6| per cent. I did not

examine the gasses.

Potash, which lias not the least action on pitcoal, to my Potash dis*
astonishment perfectly dissolved the turf. The solution jg ^^^ ^^^ ^"'" •
coffee-coloured. Acids decompose it, thrbwing down a
brown fiocculent precipitate, which distillation renders black,
shining, and fragile. When distilled it is converted into
charcoal, without softening or diminishing in bulk ; yields
the butyraceous product; and is reduced to '50 of char-
coali

Nitric acid at 30'^ does not decompose turf, as it does pit- ]sjit,i(. acid
COai. Washed and dried it affords water, and the butyra- ^o-s not du.
ceous matter, but no acid* It might be supposed, that this ^°"^P^^^ ^^'
suet exists ready formed ia turf. This- deserves to be far-
ther

17(> ^^ MURIATIC LtllLIi,

tljer exainiHed, and particAilarly to be compared with tlio-^^*
plants, the bituminization of which is not far advau- ed, tQ

■ see what changes its progress effects in their constitntjoii.

By hoiling dis- Nitric acid of 40°, with a boding heat, dissolves tn\f.

solves It. Crj'stallizable oxalic acid is oV)tained from it, and thj yel-

low bitter matter ; but no detonating product, like that of
jet. T know not whether Hatchett's tannim be found in it.

Incinovated. Its incineration is tolerably slow. Its coal does not emit

the aramoiiiacal smell of azotlzed charcoals. Its ashes arc*
gray, without the least indication of saline matter or lime.
Their lixivium does not alter tlie juice of the blue-bottle*
Acids do not occasion the slightest eJ^ecvcscence with theiri.
They contain a great deal of silex, sulphate of lime, and st
little magnesia.

II.

Ahslract of a Memoir on Muriatic Ether, read at the Insti-
tute February the lyth, 180/, bt/ Mr. Tiienard*.

Mnnatic ether jtjlFTER having examined why muriatic ether has re-
hi herto un-

kriowa° """ niained hitherto unknown to chemists, though it has been

repeatedly an object of their research, the author gives the

A gas at the process for obtaining it. As it is habitually in the state df

pemluro ^'''^" g^^' ^^^*^ following apparatus must be employed.

Arrantf<-mcr.t I'^to a retort, capable of containing no more than the mix-

of the appara- turc in its belly, equal parts by measure of highly concen-

lus for obuin- ^j.^jg^ muriatic acid and alcohol at 3ij° are to be put, and

well shaken, to bring all the particles of each into contact.

This done 7 or 8 grains of sand at most- are to be thrown

into the retort, to prevent th^ sudden ebullitions that might

otherwise take place in the course of the process : aftet

xvhich it is to be supported on the naked fire of a common

furnace by a grate of iron wire, and a Welter's tube adapted

to it, terminating in a threeiiecked bottle, the capacity, of

which is double that of the retort, and which must be half

• Annales (le Chimie, vol. LXI, p. 201, March, 1807: andjoufnal
4c Physi:]ue, vol. LXIV, p. i'60.

filled

ON MURIATIC ETHEA. 177

fiHed with water at 20® or 25° [66^ or 72** F.]. THe tube
must be immersed in the water to the depth of 7 or 8 cent.
[2f or 3 in.]; a strai^^ht tube of safety must be introduced
into the central tubulure; and from the third a curved tube
must proceed, opening under inverted phials filled with wa-
ter at the same temperature in an earthen bowl.

The apparatus being thus arranged, the retort is to be Process,
heated gradually ; and twenty or five and twenty minutes
after the fire is kindled bubbles will be seen to rise from the
lower part of the fluid, particularly from the surface of the
grains of sand. These bubbles presently become more nu-
merous, and abundance of ethereous gas is soon obtamed.
Acid, alcohol, and water, at the same time pass ovor, but
remain in the first phial. From 500 gr. [7722| grs.] of acid, Proportion of
and an equal bulk of alcohol, jupward of 20 litres [wiiue g'^s obtained,
-quarts], or even as far as 30, of ethereous gas, perfectly pure,
may be obtained. Much more will be obtained, if, as soon
as the extrication of gas begins to slacken, fresh alcohol be
added to the residuum ; that is, to the strongly acid resi^
duum, which remains in the retort, and will then be about

two fifths of the bulk of the original mixture. I even think, „ , , , ...
. P , ' Probably still -

that, rf hot alcohol were occasionally poured into the retort more by parti-
through a tube 6 or 7 decim. [24 or 27 in.] long reaching '"^"^^ manage-
to its bottom, the formation of etherized gas would be still
more abundant ; for it is obvious, that more alcohol than
muriatic acid rises every instant, thus therefore we should
reestablish their original proportions, which are best adapted
to the success of the process. In all cases the management Great atten-

<*f thte fire is of the highest importance : if it be too weak *'°" ^^ the fire

... , 1 "• 1 . , . requisite.

It wjil produce no etherjzed gas ; li it be too strong, it will

produce but little. Neither will the alcohol be etherified in If the acid, or

«:ny sensible degree by loading it with muriatic acid g-as, or ^«'^'^- '" ^!^^
1 • 1 I 1 1 I • -I < , r* ' state of gas, lit-

by causing tiie alcohol and acid both to meet in vapour in tie or no ether
a tube about 80^ [I74f ° F.]. It is only therefore by main- ^ili Reformed,
taining a due medium in the application of the fire, that we
can 6u<^ci?€d completely. The cauae of this is, that too
great or too little elasticity in the alcohol and in the muriatic
acid is injurious to their mutual action on each other. Ano- The water dis-
ther precaution to be taken is, to use the same water for col- solves a certaia
Vol. XyiU— Nov. I807. N lectino- quantity.

17S ON MURIATIC ETHEE.

lecting the gas, afid to employ as little as possible, because
it dissolves a certain quantity of it.
Characters of The gas is perfectly colourless ; it has a strong smell of
^ ^^' ether ; and its taste is perceptibly saccharine. It has no

action whatever on infusion of litmus, sirup of violets, or
limewater. Its specific gravity, compared with that of
the air, is 2-219 Jit 18« [63° F.], and 75 cent. [29*4 in.]
of atmospheric pressure. At this pressure water dissolves
its own bulk. At the same pressure, but at the tempe-
rature of 11° [50° F.], the gas assumes the liquid state.
Method ofob- A large quantity may be procured in this state by emplojv
taiiiing the Jng an apparatus similar to that already described ; only in-
quid state. stead of causing the last tube to open under a bottle filled
with water it must be made to reach to the bottom of a long,
narrow vessel, well dried, and surrounded with ice, which
must be renewed as it melts. The ethereous gas will arrive
alone in this, and be completely condensed : for as soon as
all the common air is expelled from the vessels, their commu-
nication with the atmosphere msj-y be cut off without danger.
Characters of This ether in the liquid state ig remarkably limpid. Like
the liquid ^j^g gas it is colourless, and has no action on litmus or sirup
. * of violets: is very soluble in alcohol, from which it may in

great part be separated by water : has a very decidecl smell,
and a very distinct taste resembling that of sugar, which is
particularly observable in water saturated with it. Proba-
'bly it may thus be employed with success as a medicine.
Poured on the hand it suddenly enters into ebullition, and
produces considerable cold, leaving a small whitish sediment.
At the ternperature of 5^^ [39^2° F.] its weight is to that of
Fater as 874 to 1000. Thu§, though it is much more vola-
tile than sulphuric ether, and of course than alcohol, it is?
not only heavier than the first, but even than the second of
these. Finally itiloes not congeal at a temperature of- 29**
[2^-2° below OF.].

Thus far we s^e nothing in this ether but agrees with the

phenomena exhibited by other bodies. It is an object of

curiosity only on account of its novelty, and the facihty

with which it is converted into a gas or a Hquid. But if w^

A -lingular study it farther, it will appear one of the most singular and

compound. extraordinary compounds we caii form. It; does not redden

the

ON MURIATIC FTHER. 179

the most dilute infusion of litmus; the strongest alkalis have No test indi-
1 - . /. •! • 1 1 • ^1 cates the pre-

no action ou it ; the solution of silver is not rendered lu the ^^^^^^^ of murU

least turbid by it: and all this whether it be used in the atic acid in it,
gaseous or liquid state, or dissolved in water. But set it on ^ greal'quan-
fire, and ianmediately such a large quantity of muriatic acid tity when
is developed, that it precipitates a concentrated solution of
nitrate of silver in a solid mass, sufix)cates those who inhale
it, and is even visible in the form of vapour in the surround-
ing air.

Is the muriatic acid formed in this combustion, as we is the acid then
might be tempted to suppose? or is it only set at libert3^ formed,oronly
which is possible ? These questions Mr. Thenard afterward
endeavours to solve.

If the muriatic acid be formed in the combustion of the If the former,
ethereous gas, the radical of this acid must exist in the gas ; jf^^^^f^^liTthe
and it must necessarilyproceed from the alcohol, or from the alcohol, the
muriatic acid decomposed by the alcohol, or, which is ira- ^*^^^» orboti.
probable, though not impossible, from both together. In Tests of these
the first case, on distilling a mixture of niuriatic acid and J.JJ"®^^^ supposi-
alcohol, we should find after the distillation all the muriatic
acid employed, beside what arises from the combustion of
the gas formed. In the second case, on the contrary, a large
quantity of acid ought to disappear in the distillation : but
the whole of this quantity, and no more, ought to reappear
on the combustion of the acid formed, in the third case,
a loss of acid should be occasioned by the distillation ; but
this loss should be more than compensated by the quantity
of acid, which is produced from the combustion of the gas
formed.

Now if the process be performed with 450'937 grq.m. Proof that the-
[6062-722 grs.] of muriatic acid, of the specific gravity of [^"^^^^^f ^f^^^^j^^^
11*349, at temperature 5° [39*2° F.], with an equal bulk of alcohol alone,
highly rectified alcohol, 23 lit. [quarts] of ethereous gas
will be formed at the temperature of 21° [68° F.]. and pies-
sure -745 met. [29*2 in.], and 122-288 gram. [1888*738 grs.]
of acid disappear. Consequently the first supposition is
false, since it is demonstrated, that, if the radical of the
muriatic acid exist in the ethereous gas, it must proceed,
not from the alcohol solely, but either from the muriatic acid
alone, or from the muriatic acid and alcohol.

IS 2 Z.et

180 py MUftlATTC ETHEft.

It might pro- Let us see whether it can proceed from the muriatic acid
add afoi^ \n ^^^iie, agreeably to the second supposition. There are two
two ways. ways in which this may he conceived to take place : either
the muriatic acid may have been decomposed by the alco-
hol, so that its radical is found in the ethereous gas separated
from its other principle : or the decomposition may have
taken phice in suph a way, that both the principles of the
muriatic acid exist in the etiiereous gas, not united together,
not forming muriatic acid, but combined with the principles
of the alcohol, in the same state in which hidrogen, oxigen,
carbon, and azote, are found in vegetable and animal sub-
stances.
If the radical Now if the radical of the muriatic acid exist alone, or

aloue enter m- ^j^jjQjj^ gQprie pjjit of the other principle, in the ethereous

to the ga^j n ' i i x • • i i i

cannot lep.o- gas, we ought to obtain no acid, when we decompose this

due- he acid ™jjg \^-^ ^ redhot tube with exclusion of air, or less than dis-
when buraed ° . . , . t, -^ ,

without access appeared m the expermient that produced it. But if the

of air. gjjs contain not only the radical of the muriatic acid, but all

li enter'into ^^^ constituent principles ; as the principles of this acid,

it, the wliole whatever they arc, have a great tendency to corrt.bine toge-

iSpioduced!^ thi. •', we ma i/rr nine, ihat, on destroying the ethereous g^s

by fire v/ith( iit liie contact of air, we shall probably obtain

the whole quantity of muriatic acid, that disappeared in the

exp<^riment in which the gas was formed. "

The gas de- It was of t\ie highest rmportance therefore, to effect this

conpos; d iii decomposition in close vessels. This was accordingly done

with 900 gram. [29 o?. troy] of concentrated muriatic acid,

and an equal bulk of well rectified alcohol. Between the

redhot tube of glass, in which the gas was decomposed, and

the retort where it was produced, a large tubulated bottle

was placed containing water at IS^orlG*' [57° or 59^ F.],

to retain the acid, alcohol, and water, that might rise with

the gas. The glass tube l:(ad a comrQunication also with

"two other bottles, one containing water, the other potnsh,

~'l!o kt)sor6 all the acid that might reappear in the operation,

■ iLlistiy by means of another tube the gasses were collect*

ed. That this operation may be attended with success,

the glass tube must be well coated, and the fire ca^u-

' lioui^ly managed, to prevent it from melting. Though

ucas

O^ MURIATIC ETHEHi |g|

ft'ear ^)0 litres of tthereoiis gas must have been produced in

this (Experiment, and near 250 gram, of acid have disappeared N<2arly the
. . !. • , . , r , • , whole of the

m the first instance, yet the whole ot the acid, except 4- gram, acid repro-

[62 grs.] reappeared in the rcdhot tube, and were dissolved ^"c^*

in the last two bottles of the apparatus. "^

Thus of all the suppositions above made, which are the The elements

only ones that can reasonably be formed Considering the mu- therefore exist

riaiic acid as a compound, there is only one admissible ; in the gas, if it

which is, that the elements of the muriatic acid exist in the ^ ^ ^°'^"

, . , . pound.

ethereous gas combined with those of the alcohol, in the same

manner as the elements of water, carbonic acid, ammonia,

&LC., exist in vegetable and animal substances.

But if we suppose the muriatic acid to be a simple sub- Supposition
., • 1 ^1 ^1 that the acid

stance, we must necessarily consider the ethereous gas as jj..^gijj^p]^gjy{^

formed of muriatic acid and alcohol, or as a substance de- stance,
rived from the decoiiiposition of the alcohol : for perhaps the
alcohol is decomposed when we distill it with muriatic acid,
at least this will easily be seen by and by. The question there-
fore being reduced to a choice between these two hypotheses,
let us endeavour as far as possible to discuss their weight.

The latter presents us witli phenomena very diflicult to ex- Difficulties
plain* In fact we must suppose that the alcohol, or the prin- obSc'tecf to^it.
ciple it contains, acts on the muriatic acid with much more
energy than the strcmgest alkali ; since this alkali cannot take
the acid from it, and muriate of potash, as I shall hereafter
uhow, contains less acid than the ethereous gas. How too can
\ve conceive, that nitrate of silver, which takes the whole of
the muriatic acid from muriate of potash, cannot take any"
from the ethereous gas, which contains still more?

On the other supposition, on the contrary, every thing is The other
naturally explained. We see why the ethereous gas does not naturally ac-

11 ^ ■ r ■ 'T I 11T1 yv • COUntS fof

redden the intusion or litmus; why alkalis do not aflect it ; every thing,
why nitrate of silver does not produce a precipitate with it;
and why on burning it so large a quantity of muriatic acid is
generated, that it appears in the surrounding air in the form of
vapour: in short every thing is reconcilable with the pheno-
mena exhibited by other substances.

Mr. Thenard however is far from absolutely adopting one Yet it cannot
hypothesis and rejecting the other. Both deserve to be inves- arabsoluSy^

tigated decided.

1S2 O* MtyRlATIC ETHER,

tigatcd, aud on this he is at present eagerly engaged, sinccj
however it may turu out, the results cannot lall to be very
important.

Note on the Discovery of the Muriatic Ether; hy Mt,
Thenard.
The muriatic When on the 18th of February last 1 read to the Institute
known la"^' my paper on muriatic ether, all the members, among whom
France, were Messrs. BerthoUet, Chaptal, Deyeux, Fourcroy, Guyton,

Vauquelin, and Gay-Lussac, considered the results it con-
tained as perfectly novel, and were struck with the conse-
and in Spain j quences, that might be deduced from them. Mr. Proust, who
is at present in Paris, and before whom I was eager to repeat,
at his desire, the experiments I had made with the ethereous
gas, was not less surprised than the French chemists. But
last friday, that is twenty-five days after I had read my paper,
but not inGer- j\|jr^ Gay-Lussac, turning over Gehlen's Journal, accidentally
found in a note, that Gehlerj himself had made experiments
on muriatic ether, and recorded them in on& of the volumes
of his Journal published in 1804.
Gehlen made ^^ appears, that Mr. Gehlen made muriatic ether from
it in dififerent equal weights of the fuming muriate of tin and alcohol. He
■' ' likewise made it in Basse's method, by a mixture of seasalt,

concentrated sulphuric acid, and alcohol ; from which till
Basse's time, and even Gehlen's, sulphuric ether onl}' was
supposed to be obtained. He did not obtain any with muri-
atic acid alone. Mr. Gehlen however observed most of the
properties in muriatic ether, that I have mentioned. The
chief differences between us are, that he has not attempted
to investigate the source of the muriatic acid produced by
burning the gas, the quantity it is capable of affording, or the
Hk'wAslessin *^®°^y ^^ *^^^ formation of the ether. My process-too not
quantity, and only affords ether in larger quantity probably than any other,
less pure, jj^j much purer; for the specific gravity of mine was '87 ^y of

his only "845, and in this case the greater gravity is a proof
of greater purity. He likewise marks tlie point of its conden-
gation as about 10° of Reaumur [54'5° F].

As from the account of Mr. Gehlen I could no longer
doubt but muriatic ether had been made in Germany, and its

property

ACTION OF MURIATES, •&C. ON ALCOHOL. 183

{)roperty of yielding a large (juantity of muriatic acid in
burning observed ; and at the same time convinced, that a
fact so important was altogether unknown both in France .and
Spain ; I was desirous of satisfying myself, whether the Kng- Not known in
lish chemists were any farther advanced in this respect. For ^
this purpose I addressed myself to Mr. Riffault, who is trans-
lating the third edition of Thomson's Chemistry, a work of
great erudition, begun long after Gehlen's paper was pub-
lished. Mr. Riffault read to me every thing in it concerning
muriatic ether. No mention is made ihere of Gehlen, or of
the singular properties of the muriatic ether. Hence I con-
sider myself authorized to conclude, that the muriatic ether
was unknown in England, as well as in France'and Spain;
and that, without having information of Gehlen's labours, I
hiay claim at least the merit of having made it known here.
How often has it already happened/that a discovery has been Discoveries of^
made in one country some years after it had been made in ^.^^^^y ^ji^g the
another ; and this because unfortunately all learned men do first remaining
not speak the same language, and all the works published in foJeieners.^^
one are far from being translated into the rest.

In an additional note Mr/Fhenard says, that, ten days after
his paper was read, Mr. BouUay, an Jipothecary of Paris, ac- Mr.BoulIay
quaintedhim,thathehad likewise formed muriatic ether direct- ^°^^^*^ ^^^
ly from muriatic acid and alcohol, but had not made it public,
because he had not yet completed his labours on the subject.

HI.

Abstract of a Memoir on the Products tlidt result from the
Action of Metallic Muriates^ oxigcnized Muriatic Acid, and
Acetic Acid, on Alcohol : by Mr, Tii en a r D *.

I

N this paper Mr. Thenard shows, that the nvetallic mtiri- Metallic muri*
ates form but a very small quantity of ether with alcohol : ^.^^ ^^^-^ ^"^"^
that this ether, which at first is found dissolved in a large withaicohoL
quantity of alcohol, may be separated from h in the state ofc

• Annales de Chimie, tol. LXI. p. SOS, March, 1807.

aM

ACTION or MURIATtS, &C. ON ALCOHOL,

Kot so volatil*
as that frop
the acid.

Formed
wholly from
tlie excess of
acid inthemu
riate.

Oxigenized
muriatic acid
decomposed
by alcohol.

But no ehter
produced.

Mistake of
45cheele in this
respect.

gas by a n;entle heat ; particularly by mean'* of hot water,
which seizes on the alcohol, and to a Certain poit.t sets the
ether at liberty: that this ethereous gas has the greHtost Hiia-
lojry with that which is obtained from muriatic acid nnd
alcohol: that both have the same smell, taste, and solubility
in water, and burn in the same' manner with a grem flame,
and diffusinfi; vapours of muriatic acid, though nrevious to
the combustion no test can delect the presence of any in the
gas: and that thry differ only in this,, that the muriatic ether-
eous gas is not condensible at a temperature above I'i*^''
[or?" F], while the other is at l6-5« [6o" F.]

This difference being but slight, Mr. Thenard conceives,
that the nature an»l mode of formation of both are the same;
and that in the metallic muriates it is only the excess of acid
that acts on the alcohol. For this reason a large quantity of
metallic muriate is necessary to convert alcohol into ether;
and it is the more easily effected, in proportion as the muriate
contains a greater excess of acid, and is more soluble in alco-
hol. Hence the process succeeds better with the muriate of
tin than with any other. In every case the muriate is not
disoxigenized, and a portion of the oxide only is found to be
precipitated.

Considering afterward the action of oxigenized muriatic
acid on alcohol, he shows, that in the mutual action of these
two substances on each other, which is very powerful, almost
all the oxigenized muriatic acid is decomposed: and the re-
sult is a great deal of water; a great deal of muriatic acid ;
some alcohol not decomposed ; a tolerable quantity of an oily
matter heavier than water, having a cool taste analogous to
that of mint, a peculiar smell differing from that of ether ;
and beside these a small quantity of carbonic acid, of a sub-
stance easily carbonized, and probably of acetous acid, but no
ether. Farther, that the oxigenized muriatic ether of Scheele
is nothing but muriatic ether properly so called, when
made with a mixture of alcohol, muriatic acid, and black
oxide of manganese; or a mixture of muriatic and sulphuric
ether, when made from black oxide of manganese, common
•salt, alcohol, and sulphuric acid: that Pelietier's is of the
same nature,. since he made it of a similar mixture: and that

what

ACTION OF MURIATES, &C. ON ALCOHOL* } S5

i\'hat is said to be abtaincd by passing; oxigenized muriatic acid Solution of a

Lms throiidi alcohol is nothing but a solution ol more or less peculiar oil lit
^ -^ " alcohol mista-

of the oily matter in alcohol. The oil may even be separated ken for eiliw,

from th€! alcohol by the addition of water, and the same com-
pound formed again by dissolving this oil in a given quantity
of alcohol.

What is new in this part of Mr. Thenard's labours is not
the formation of the oily matter, water, acetous, acid, &c., by
the decomposition of oxigenized muriatic acid: for Scheele,
in his Chen)ical Essays, speaks of the oily matter; and Ber-
thollet, in the Memoirs of the Academy for 1785, speaks not
only of this, but of the water, acetous acid, &c., formed in
the process: but it is the having proved"^, that oxigenized
muriatic acid cannot form ether with alcohol, and having ex-
pluified why Scheele and so many other chemists did
obtain some.

Finally, desirous of examining the formation of acetic Acetic ethejv

ether, Mr. Thenard mixed together 120 gram. [1853 grs.] of

alcohol as highly rectified as possible, and as much acetic

acid, of an acidity determined by the quantity of potash the

jacid requires to saturate it. He distilled the mixture, coho-

bated it twelve limes, and thus evidently decomposed all the

alcohol employed, beside 66' \6 gram. [1022 grs.] of acetic

acid, answering to 32 gram. [509 grs.] of dry acid, or such as

it exists in acetate of potash well fused. Yet about 120 gr,

[1853 grs.] only of acetic ether were formed; though no gas

was evolved, and, when the process was finished, a loss of 7

gram. [108 grs.] only appeared. Hence Mr. Thenard is led

^, , . r .1 . /> t . . . .'Water formelt

to suppose, that part of the oxigen of the acetic acid com- in this procesa,

bines with part of the hidrogen of the alcohol, while the other
principles of the acid, and those of the alcohol, unite to form
the ether. Otherwise, if no water were formed, we must ad-
mit, in order to account for the appearances, that the best
rectified alcohol contains nearly a fifth of its weight of water,
which is scarcely probable.

This

• Mr.Berthollet even mentioned, that the oxigenlzod muriatic acid
and alcohol produced but very little ether ; and we perceive, that hy ii>
clined to consider this small quantity of ether as foreign to the mutual
action of these two substances.

tSfi HtNTS ON ACCLIMATING tENDER PLANTS.

Characters of This ether has an agreeable smell of ether and acetic acid ;

acetic ci er. ^^^^ j^ reddens neither the infusion nor paper of litmus: and
it has a peculiar taste, not very different from that of alcohol.
N^either its spqcific gravity nor degree of elasticity was ac-
curately ascertained : but it is lignter than water, and swims
on it, and heavier than alcohol. Water appears to dissolve
Imuch more than it does of sulphuric ether. It burns with a,
yellowish white flame, and produces an acid, which is probably
the acetic. It does not appear to undergo any alteration by
keeping;, at least It did not in the course of six months.

IV.

Some Hints respecting the proper Mode of inuring Tender
\ Plants to our Climate. B(j the Right Hon, Sir Jose Pit

Banks, Bart. K. B. P. K. 6'. 4'C*v

tnteresting and Jt^ESPECTABLE and useful as every branch of the horti-^

advantageous Qu^m-^l art certainly is, no one is more interesting; to the

to harden ten- -^ ^

<er plants. public, or more likely to prove advantageous to those who

may be so fortunate as to succeed in it,, than that of inuring
plants, natives of warmer climates, to bear without covering
the ungenial springs, the chilly summers, and the rig(,rous
winters, by which, especially for some years past, we have
been perpetually visited,
. Many attempts have been made in this lire, and several

this way. valuable shrubs, that used to be kept in our stoves, are no\f

to be seen in the open garden ; there is, however, some rea-
son to believe, that every one of these was orginally the na-
tive of a cold climate, thpugh introduced to us through the
medium of a warm one ; as the gold tree, aucuba japonica,
the moutan, paeonia frutescens, and several others have been
in our times.

In the case of annuals, however, it is probable that much
Las been done by our ancestors, and something by the pre-
sent generation; but it must be remembered, that all that
is required in the case of an annual is, to enable it to ripen

• From the Transactions of the Horticultural Society, Part I, p, 21.

its

illNTS ON ACCLIMATING TENDER PLANTS*

m

its fruit in a comparatively cold summer, after which we
know that the hardest frost has no power to injure the seed,
though exposed in the open air to its severest influence ; but a
perennial has to encounter frosts with its buds and annual
shoots, that have sometimes been so severe with usj as to rend
asunder the trunks of our indigenous forest trees.

It is probable that wheat, our principal food at present, Wheat*
did not bring its seed to perfection in this climate, till
hardened to it by repeated sowings; a few years ago some
spring wheat from Guzerat was sown with barley, in a well
cultivated field : it rose, eared, and blossomed, with a healthy
appearance, but many ears were when ripe wholly without
corn, and few brought more than three or four grains to
perfection.

In the year 1791, some seeds of zizania aquatica were Water oaft
procured from Canada, and sown in a pond at Spring Grove,
near Hounslow ; it grew, and produced strong plants, whic^h
ripened their seeds; those seeds vegetated in the succeeding
spring, but the plants they produced were weak, slender, not
half so tall as those of the first generation, and grew in the
shallowest water only; the seeds of these plants produced
others the next year sensibly stronger than their parents of
the second year.

In this manner the plants proceeded, springing up every Gradually ac-
year from the seeds of the preceding one,^ every one becom- cli"^^*^^*
ing visibly stronger and larger, and rising from deeper parts
of the pond, till the last year, 1804-, when several of the
plants were six feet in height, and the whole pond was in
every part covered with them as thick as wheat grows on a
well managed field.

Here we have an experiment which proves, that an annual till perfectly
plant, scarce able to endure the ungenial summer of England, ^g|°g°"^ "^ ^^
has become, in fourteen generations, as strong and as vigo-
rous as our indigenous plants are, and as perfect in all its
parts as in its native climate.

Some of our most common flowering shrubs have been long Bay ti«e.
introduced into the gardens; the bay tree has been cultivated
more than two ctjnturies ; it is mcRtioned by Tusser, in the

list

188 HINTS ON ACCLIMATING TENDER PLANTSi

list of garden plants inserted in his book, culled 500 points of

good Husbandry, printed in 1573.
laurel. The laurel was introduced by Master Cole, a meiLchant

living at Hampstead, some years before l6'29, when Parkinson

published his Paradisus Terrestris, and at that time we had in

Orange, myr- oui' gardens, oranges, myrtles of three sorts, laurustinus, cy-

lie, Ac. press, phillyrca, alaternus, arbutus; a cactus brought from

passion flower i^t'rmudas, and the passion flower, which last had flowered

femarkable here, and showed a remarkable particularity, by risins; from
particularity. ^, , , ... ,,. , . '' .

the ground near a month sooner it a seedling plant, than if it

grew from roots brought from Virginia.

All still tender. '^^^ these were at that time rather tender plants; Master

Cole cast a blanket over the top of his laurel, in frosty wea*

ther, to protect it, but though nearly two centuries hav0

since elapsed not one of them will yet bear with certainty

our winter frosts.

*, ., Thoudi some of these shrubs ripen their seeds in this cli-

Hate not been o i

propztgated by mate, it never has been, I believe, the custom of gardeners to

ittgiish seed. ^^^^ them ; some are propagated by suckers and cuttings, and

others by imported seeds; consequently the very identical

laurel introduced by Master Cole, and some otliers of the

plants enumerated by Parkinson, are now actually growing in

our gardens; no wonder then, that these original shrubs have

not become hardier, though probably they would have done

so, had they passed through several generations by being

raised from British seeds.

Plants propa- ^^ '^ ^^"^ ^'^^^^ worthy a trial, as we find that plants raised

gated by cut* from suckers or cuttings do not grow hardier by time, and as

tings or suckers , » ^ ■ • • \ ^ ^i i ^i

do not grow ^"® experiment on zizania points out the roao, to sow tJic

hardy. Seed seeds of these and such tender shrubs as occasionally ripen
should b« them in this climate. Fourteen generations, in the case of the
tried. zizania^ produced a complete habit of succeeding in this cli-

mate, but a considerable improvement in hardiness was evi-
dent much earlier.

In plants that require some years to arrive at puberty,
ft)Ulteen generations is more than any man can hope to sur-
vive; but a much less number will in many cases be sufficient,
and in all, though a complete habit of hardihood is not at-
tained, a great progress may be made towards it in a much

less

METHOD OF PRODUCING NEW AND EARLY FRUITS. | gj

less time; even one generation may work a change of no
small importance, if we c«uld make the myrtle bear the cli-
mate of INIiddlesex, as well as it does that of Devonshire, or
exempt our laurel hedges from the danger of being cut down
by severe frosts, it would be an acquisition of no small conse-
queiice' to the pleasure of the gentleman, as well as to the
profit of the gardener.

Old as 1 am, I certainly intend this year to commence ex- Myrtle ana
periments on the myrtle and the laurel: I trust, therefore, it laurel begua

•1. . 1 .1 I ^ . • • •. .1 c to be tried,

will not be thought presumptuous in me to invite those ot my

brethren of this most useful Society, who are younger than I
am, luid who of course will see the effect of more generations
than I shall do, to take measures for bringing to the test of ex-
periment the theory I have ventured to bring forward; I hope
not without some prospect of success.

The settlement lately made at New Holland gives a large NewH-.lland
scope to these experiments; many plants have been brought ^[^^^^^^ °'^°^
thence which endure our climate with very little pro-
tection, and some of these arrive at puberty at an early pe-
riod ; we have already three from the south point o'' Van
Die men's Island, where the climate cannot be wholly without
frost; mimosa verticillata, eucalyptus hirsuta and obliqua.
The first of these appears to have produced flowers within
eight years of its first introduction, but as a settlement is
now made very near the spot where the seeds of these shrubsf
were collected, we may reasonably hope to receive farther
supplies, and, among them, the winterana aromatica, an in-
habitant of the inhospitable shore of Terra del Fuego, which
Mr. Brown has discovered on the south part of Van Diemen'.'i
Island also.

V.

Observations on the Method of producing new and early Fruits.
By Thomas Andrew Knight, Esq: F.R.S. Sfc*

J- nI ATURE has given to man the means of acquiring those Gifts of naturo
tilings which constitute the comforts and luxuries of civilized b"" ""mln ^''^^^'^

* Transactions of the Horticultural Society, Part I, p. SO,

life

IQO METHOD Of PRODUCING NEW AND EARLY FRUITS,

life, though not the things themselves; it has placed the
raw material within his reach ; but has left the preparation
and improvement of it to his own skill and industry, Every
plant and animal, adapted to his service, is made susceptible
of endless changes, and, as far as relates to his use, of almost
endless improvement. Variation is the constant attendant
on cultivation, both in the animal and vegetable world ; and
in each the offspring are constantly seen, in a greater or less
degree, to inherit the character of the parents from which
• they spring, '

"Fruits best In No experienced gardener c^n be ignorant, that every spe-?
situation ^^and ^^^^ ^^ ^'""^^ acquires its greatest state of perfection in some
management, peculiar soils and situation.-, and under some similar mode
of culture: the selection of a proper soil and situation must
therefore be the first object of the improver's pursuit; and
nothing should be neglected which can add to the size, or
improve the flavour of the fruit from which it is intended to
Hence new va- propagate. Due attention to these points will in almost all
cases be found to comprehend all that is necessary to insure
the introduction of new varieties.of fvait, of equal merit with
those from which they spring ; but the improver, who has to
adapt his productions to the cold and unsteady climate of
Hardiness and Britain, has still many difficulties to contend with ; he has
desirable^" "^ ^^ combine hardiness, energy of character, and early matu-
rity, with the improvements of high cultivation. Nature has,
however, in some measure, pointed out the path he is to pur-
sue; and, if it be followed with patience and industry, no
obstacles will be found, which may not be either removed,
or passed over.
Plants carried If two plants of the vine, or other tree, of similar habits,
to a hot o» cold Qj, even if obtained from cuttinjjs of the same tree, were

climate and -, . ' V •

brought back, placed to vegetate, dunng several successive seasons, m very
different climates ; if the one were planted on the banks of
the Rhine, and the other on those of the Nile, each would
adapt its habits to the climate in which it was placed ; and
if both were subsequently brought, in early spring, into a
climate similar to that of Italy, the plant which had adapted
its habit-s to a cold climate would instantly vegetate, whilst
the other would remain perfectly torpid. Precisely the same

Hothouses. thing occui*s in the hothouses of this country, where a plant

accustomed

HETHaD OF PRODUCING NEW AND EARLY FRUITS^ 1(J|

accustomed to the temperature of the open air will vegetate
strongly in December, whilst another plant of the same spe-
cies, and sprung from a cutting of the same original stock,
but habituated to the temperature of a stove, remains appa-
rently lifeless. It appears, therefore, that the powers of Pl^»<^3 from

1, ,-... , 11- 1 11 T X col^^ climate*

vegetable lite, in plants habituated to coid climates, are gj^^i^s^^

more easily brought into action than in those of hot cli-
mates; or, in other words, that the plants of cold climates
are most excitable : and as every quality in plants becomes
hereditary, when the causes which first gave existence to
those qualities continue to operate; it follows that their seed-
ling offspring have a constant tendency to adapt their habits
to any climate in which art or accident places them.

But the influence of climate on the habits of plants, will Not theaggre-
1 11 1 ...[' 1 ^ • LI- gate quantity

depend less on the aggregate quantity or heat m each ch- of heat butit«

mate, than on the distribution of it in the different seasons distributioa
jof the year. The aggregate temperature of England, and Benson, the
of those parts of the Russian empire, that are under the chief point,
same parallels of latitude, probably does not differ very con- Ruf^^^!
siderably ; but, in the latter, the summers are extremely
hot, and the winters intensely cold ; and the changes of
temperature between the different seasons are sudden and
violent. In the spring, great degrees of heat suddenly ope-
rate on plants which have been long exposed to intense cold,
and in which excitability has accumulated during along pe-
riod of almost total inaction ; and the progress of vegetation
is in consequence extremely rapid. In the climate of Eng-
land, the spring, on the contrary, advances with slow and
irregular steps, and only very moderate and siowly-increaaino-
degrees of heat act on plants in which the powers of life
have scarcely in any period of the preceding winter been to-
tally inactive. The crab is a native of both countries, and
has adapted alike its habits to both ; the Siberian variety in- Siberian crab.
troduced into the climate of England retains its habits, ex-
pands its leaves, and blossoms on the first approach of sprin«-,
and vegetates strongly in the same temperature in which the
native crab scarcely shows signs of life ; and its fruit acquires
a degree of maturity, even in the early part of an unfavoura-
ble season, which our native crab is rarely or never seen to
attain.

Similar

ig2 METHOD OF PRODUCING NEW AND EARLY FRUITS.

Annuals. Similar causes are productive of similar effects on the

habits of cultivated annual plants ; but these appear most
readily to acquire habits of maturity in warm climates ; for
it is in the power of the cultivator to commit his seeds to the

Seeds from a earth at any season ;^ and the projjress of the plants towards

warm climaie maturitv will be most rapid, where the climate and soil are
ripen earliest. * ^ ^

most warm. Thus the barley grown on sandy soils, in the

warmest parts of England, is always found by the Scotch
farmer, when introduced into his country, to ripen on his
cold hills earlier than his crops of the same kind do, when
he uses the seeds of plants, which have passed through seve-
ral successive generations in his colder climate; and in my
own experience, I have found that the crops of wheat on
some very high and cold ground, which I cultivate, ripen
much earlier when I obtain my seed-corn from a very warm
district and gravelly soil, which lies a few miles distant,, than
when I employ the seeds of the vicinity.
Ksculent The value, to the gardener, of an early crop, has attract-

plants. ^^ j^j^ attention to the propagation and culture of the ear-

liest varieties of many species of our esculent plants; but in
the improvement of these he is more often indebted to acci-
dent than to any plan of systematic culture; and coatents
himself with merely sdecting and propagating from the
plant of the earliest habits, vvhich accident throws in his
way ; without inquiring from what causes those habits have
arisen: and few efforts have been made to bring into exist-
ence better varieties of those fruits which are not generally
propagated from seeds, atid which, when so propagated,
of necessity exercise, during many years, the patience of
the cultivator, before he can hope to see the fruits of his la-
bour.
Attempts to The attempts which I have made to produce early varies

pro luce ecirly ^j^g ^^ f^.^^;^ ^^^ j [relieve, all that have yet been made; and
varieties of , ^ n ^ - ^ /r- • ^i i •

fruit. though the result of them is by no means sutnciently deci-

eive to prove the truth of the hypothesis I am endeavour-
ing to establish, or the eligibility of the practice I have
adopted, it is amply sufficient to encourage future experi-
ment.
Apples. The first species of fruit, which was subjected tcL experi-

ment by me, was the apple ; some young trees of those va-
rieties

WEtHOD eF PR0DUC'I??G KEW AND EARLY FRUITS. lf)3

rleties of tbisfiuit, from whicli I wished to propagate, were
-trained to a south wall, till they produced buds which con-
t'lined blossoms. Their branches were then, in the suc-
ceeding winter, detached from the wall, and removed to as
great a distance from it as the pliability of their stems would
permit; and in this situation they remained till their blos-
soms were so far advanced in the succeeding springs as to
be in some danger of injury from frost. The branches were
then trained to the wall, where every blossom I suffered to
tesnain, soon expanded, and produced fruit. This attained
in a few months the most perfect state of maturity ; and the
seeds aiforded plants, which have ripened the fruit very con-
siderably earlier than other trees, which T raised at the same
time, from seeds of the same fruit, which had grc^vn in the
orchard. In this experiment the fecundation of the bios- Fruit fecun-
soms, of each variety, was produced by the ^^''"^ of ano- J^^^^^J^^^^j^^^'"^
ther kind; from which process, I think, Tobtained, in this, tree.
and many similar experiments, an increased vigour and lux-
uriance of growth ; but I have no reasons whatever to think
that plants thus generated ripen their fruit earlier than others
which are obtained by the common methods of culture. I
must therefore attribute the early maturity of those I have "
tlescrlbed to the other peculiar circumstances tinder which
the fruit and seeds ripened, from which they sprang.

I obtained, by the same mode of culture, many new va- Siberian cmb
tieties, which are the offspring of the Siberian crab and the pie combined
richest of our apples, with the intention of affording fruits t^ produce ci-
for the press, which might ripen well in cold and exposed
situations. The plants, thus produced, seem perfectly well
Calculated, in every respect, to answer the object of the ex-
periment, and possess an extraordinary hardness and luxu-
riance of growth. The annual shoots of some of them, from
iiewly grafted trees in my nursery, the soil of which is by
no means rich, exceeded six feet and a half in height, in
the last jseason ; and their blossoms seem capable of bearing
extremely unfavourable weather without injury. In all the
preceding experiments some of the new varieties inherited
the character of the male, and others of the female, parent
in the greatest degree; and of some varieties of fruit (parti- Variety of th,e
cularly the golden pippin) I obtained a better copy, by in- gol^len pippin.

Vol. XVIII — Nov. IS07. O troducing

194 METHOD OF PRODUCT NG NEW AND "FARLY FRUITS.

troducins^ the farina into the blossom of another apple, than
by sowinor their own seeds ; I sent a new variety (the Down-
ton pippin) which was thus obtained fro;n the farina of the
p:olden pippin, to the Horticultural Society, last year, but
tliose specimens afforded but a very unfavourable sample of
it ; for the season, and the situation in which the fruit
ripened, w^ere very cold, and almost every leaf of the trees
had been eaten oif by insects. In a favourable season and
situation it will, I believe, "be found little, if at all, inferior
to the i;;olden|)ippin, when first taken from the tree; but it
is a good deal earlier, and probably cannot be preserved so
long.
Grape. I proceed -to experiments on the grape ; which, though

less successful than those on the apple, in the production of
good varieties, are not less favourable to the preceding con-
Vinery with- elusions. A vinery in which no fires are made during the
les. winter, affords to the vine a climate similar to that which the

southern parts of Siberia afford to the apple, or crab tree :
in it a similarly extensive variation of temperature takes
place, and the sudden transition from great comj>aratlve cold
to excessive heat is productive of the same rapid progress in
the growth of tlie plants, and advancement of the fruit to
Black cluster maturity. My first attempt was to combine the hardiness
united with the of the blossom of the black cluster, or Burgundy grape,
Sweetwater, ^y-^|^ the large berry and early maturity of the true sweet-
water*. The seedling plants produced fruit in my vinery
at three or four months old, and the fruit of some of them
was very early ; but the bunches were short, and ill formed,
and the berries much smaller than those of the sweetwater,
and the blossoms did not set by any means so well as I had
hoped,
and with the Substituting tlje white chasselas for the sweetwater, 1 ob-
tained several varieties, whose blossoms appear perfectly
hardy, and capable of setting well in the open air; and the
fruit of some of them is ripening a good deal earlier in the
present year than that of either of the parent plants. The
beriies, however, are smaller than those of the chasselas,
and with less tender and delicate skins : and, though not

• This grape is often confounded by gardener?, hoih with the white
chasselas and white jnuscadine.

without

chasselas.

METHOD OF PfeODUCING NEW AND EARLY FRUITS. IQS

Vvllhout considerable merits for the desert, they are gene-
rally best calonlated for the press : for the latteV purpose, Good forvrin^
in a cold climate,'! am confident that one or two of them ^^^g^
possess very great excellence. I sent a bunch of one of
those varieties to the Horticultural Society, in the la^t au-
tumn, and I propose to send two or three others in the pre-
sent year.

I have subsequently obtained plants from the white chas-
selas and sweetwater, the appearance of which is much more
pfomising ; and the earliest variety of the grape I have ever Y^^ ^^^^Y ^^
yet seen, sprang from a seed of the sweetwater, and the
farina of the red frontignac. This is also a very fine grape,
resembling the frontignac in colour and form of the bunch ;
but I fear its blossoms will prove too tender to succeed in
the open air in this coiintry ; a single bunch, consisting of a
few berries, is, however, all that has yet existed of this kind.
The present season also affords me two new varieties of the Vine with

vine, with striped fruit, and vafiec^ated autumnal leaves, pro- ^^"i'^^^ f"""'*

, 1 • 1 1 > . r- ^"^ variegated /

duced by the white chasselas and the farina of the Aleppo leaves.

vine: one of these has ripened extremely early, and is, I
think, a good grape. When perfectly ripe, I propose send-
ing a bunch of it for the inspection of the Horticultural
Society.

* In all attempts to obtain new varieties of fruit, the propa-
gator is at a loss to know what kinds are best calculated to
ianswer his purpose ; and therefore, I have mentioned those
varieties of the grape, from which I have propagated with
the best prospect of success. My experiments are, however. Experiments
still in their infancy; and I do not possess the means of y^'^ »^ ^lieir in*
making them on so large a scale, or in so perfect a manner as
I wish : nevertheless, the facts of which I am in possession,
leave no grounds of doubt in my mind, that varieties of the Better varieties
grape, capable of ripening perfectly in our climate, when niay no doubt
trained to a south wall, and of other fruits, better calculated ^^ pro^-uc«<i'
for our climate than those we now cultivate, may readily be
obtained ; but whether the mode of culture I have adopted
and recommended be the most eligible, must be decided by
future and more extensive practice.

1 have made experiments similar to the preceding, on the p ^.
peach ; but I can say no more of the result of them, than

O 3 tliat

IQS method of producing new and EARtY FRUITS.

that the plants possess the most perfect degree of health and
luxuriance of growth, and that their leaves afford satisfac-
tory evidence of the good quality of the future fruit. I am
ignorant of the age at which plants of this species become
May be capable of producing blossoms j but the rapid changes, in

bear at 3 or 4 *^^ character of the leaves and growth of my plants, which
years old. are now in their third year, induce me to believe, that they
will be capable of producing fruit at three or four year*
old.

I shall finish my paper with stating a few conclusions,^
which I have been ^ble to draw \yi the course of many years^
close attention to the subject on which I write.
Best mode of New varieties of every species of fruit will generally be
T^rieS "^"^ ^^-""^^ obtained by introducing the farina of one variety of
fruit into the blossom of another, than by propagating fron»
any single kind. When an experiment of this kind rs made,
between varieties of different size and character, the farina:
of the smaller kind should be introduced into the blossoms
of the larger ; for, under these circumstances, I have gene-'
i-ally {but with some exceptions) observed a prevalence in
fruit of the character of the female parent ; probably owing
to the following causes. The seedcoats are generated wholly
by the female parent, and these regulate the bulk of the
Peachv lobes and plantula ; and I have observed, in raising new va-

rieties of the peach, that when one stone contained two-
Choice of seeds, the plants these afforded were inferior to others. The
se«ds. largest seeds, obtained from the finest fruit, and from that

which ripens most perfectly and most early, should always
be selected. It is scarcely necessary to inform the expe-
rienced gardener, that it will be necessary to extract the
stamina of the blossoms from which he proposes to propa-
gate, some days before the farina begins to shed, when he
proposes to generate new varieties in the manner I have re-
Secdling tree*, commended. When young trees have sprung from the seed,
a certain period must elapse before they become capable of
bearing fruit, and this period, I believe, cannot be short-
Should not be ^ned by any means. Pruning and transplanting are both
pruned or injurious ; and no change in the character or merits of the
^^ * future fruit can be effected, during this period, either by
manure or culture. The young jilants should be suffered to

extend

DESULPHURATION OF METALS. 197

extend tlieiv branches in every direction, in whjch they do
not injuriously interfere with each other; and the soil should ^^J^ ^^^ ^^
just be sufficiently rich to promote a moderate degree of
growth, without stimulating the plant to preternatural exer-
tion, which always induces dieease*. The periods which
different kinds of fruit trees require to attain the age of pu-
berty, admits of much variation. The pear requires from AgeofbeaP"*
twelve to eighteen years; the apple, from five to twelve, or
thirteen ;^e plumb and cherry, four or five years; the vine,
three or four; and the raspberrj^ two years. The straw-
berry, if its seeds be sown early, affords an abundant crop
in the succeeding year. My garden at present contains se-
veral new and excellent varieties of this fruit, some of which
I should be happy to send to the Horticialtural Society, but
the distance renders it impracticable f.

yi.

Memoir on the Desulphurallon of Metals: by Mr, GuENl-
VEAU, Engineer of Mmes%»

■MONG the great number of metallic sulphurets, with Decomposi-

which Nature presents us, the decomposition of many is of *'^" ^^ native
, . -1 rm 1 1 r. • sulphurets im^

much importance in the arts. 1 he sulphurets oi iron, cop- portant.

per, lead, and mercury, and some others, give rise to raetai-

lurgical processes, that particularly claim the attention of

those, who are addicted to the study of chemistry. The The facts of

nature and pro^terties of these have been well known, since have-not been

cliemistry has made them an object of her labours : but as compared with

the facts collected in laboratories have never b/een carefully smeUia<^ housa

• The soil of -an old garden is peculiarly destructive.

-f Jhe hautboy strawberry does no; appear to propagate readily with Hautboy,
tte other varieties, and may possibly belong to an originally distinct spe-
pies. I have, however, obtained several offspring from its farina; but
they have all produced a fteble and abortive blossom. If nature, in any
instance, permits the existence of vegetable mules (but this I am n<jt
inclined to believe) these plants seem to be beings of that kind.

X Journal des Mines, No. 121, -p. a.

compared

ipg bESUjuPHURATION OF METALS.

compared with those that extensive works furnish, though
we are well aware, that this would be the best way of attain-
ing useful results, the theory of the various operations to
which sulphuiets are subjected has not yet been improved
by the progress of that science. My object is to supply this
defect; and to accomplish it I have collected a great many
experiments and observations, that have been long known ;
I have added some researches of my own ; and from their
examination I have deduced consequences, tl.at^must make
.pome alteration in the ideas generally entertained respecting
thfi -treatment of metallic sulphurets.

Sect. I.
Of the action of heat on metallic sulphurets.

Heat always THE action of heat on metallic sulphurets requires first
employ to de- to be examined, because it occurs in all the processes em-
compose them jpi^y^^ for their decomposition. To appreciate this with
accuracy, I have chosen experiments and observations in
which this action is completely distinct, which it is of im-
portance to remark ; for it is owing to not having analysed
the effects produced by various causes, that metallurgists
but it has not have ascribed to caloric alone a desulphurating power,

much effect which it does not appear to me to possess in any verv higli
alone.

degree.

Suluhnrets of The sulphurets of mercury and arsenic are volatilized in
mercury and close vessels, when exposed to a temperature a little elevated.
limed by It.' ^^^^ sublimed sulphuret has frequently a different colour
from that which has not been sublimed; and the experiments
of Proust and Thenard demonstrate, that this change is the
consequence of an alteration in the proportions of the ele-
ments of the compound.
That of iron The native sulphuret of iron experiences but a partial

not freid from decomposition by means of caloric. By distillation in a re-
half its sulphur ' . 1 l/» >I 11 '^ ^ ' T

ty it. tort we cannot extract halt the sulphur it contams. In

Saxony the distillation of pyrites in the large way never
yields more than 13 or 14 per cent of their weight of sul-
phur. ^

As these facts were r.ot sufficient to determine my opinion
respecting the efl[ects of heat, because all the experiments

that

DESUI.PIIURATION OF METALS, JQQ

that liad come to my knowledge were made at no very high Powdered py-
temperature,. I put into a crucible line*! with charcoal some for^anhourina
powdered pyrites, covered it with churc(jal powder, and ex- forge fire, was~
posed it for'^an hour to the heat of a forge., The result was \^^^ fj^'^ J^;
a mass still retaining all the characters of pyrites. It ap- of its sulphur,
peared to have been completely melted, and retains tvvo
thirds of the sulphur originally belonging to it. This ex-
periment, having been repeated, left me no doubt of the ef-
fects of heut alone on sulphuret of iron ; and I think I may
conclude from it, that, whatever be the temperature, only a
partial decomposition can be produced by it.

On sulphuretted copper and pyritous copper heat pro- Sulphuretted

duces effects analogous to those observed with irou. The ^"<^' pyntous
,...,. V „ . rt. 1 1 i . 1- , copper similar.

distillation (>f pyritous copper aftorded me but veiy little

sulphur. T^hese two ores however may be considered as

mixtures of the sulphurets of copper and of iron, and the

sulphur separated by heat comes from that of iron almost

wholly.

The sulphuret of lead, or galena, is one of those mine- Galepa.
rals, the tieatment of which is most, varied. All chemists
agree in considering it as a compound of sulphur and lead
only, in the proportion of 15 parts sulphur to S5 of lead. I
was the more careful in observing the eiiiscts of caloric on
galena, as in separating the sulphur by its means I might
hope to obtain metallic lead, the weight and fusibility of
which would render its union ver}'" easy. I could likewise
without difficulty exclude the air in the process.

Into a retort I put 30 gram. [463 grs.] of powdered ga- Heated gently
lena, which I heated for tvvo hours so gently as not to a^glu- g^ive out a lit-
ttnate it. Only a little sulphurous acid produced by the lcV,"but no"^ -
action of the air of the vessels was evolved, a^d I perceived sulphur.
no sulphur sublime in the neck of the retort. I then in- Heated nearly
creased the fire, and kept it thus two hours more, till both ^^ ^"sioii
5the galena and the retort experienced a commencement o^ '

fusion. The sulphur volatihzed in this second stage of the
operation was so little, that T could not detach it from the very little sul-
vessel and weigh it. The residuum had the metallic bril- P^"'^^"^^*"^®*^*
liancy, was agglutinated, and did not contain an atom of
ductile lead.

As the heat in this experiment was not very great;» I sub- Fused in a

jefted

20Q UESULP^!J9.ATfjON QF METALS.

fprg- fre jected to a forge irie «ome powdered galeim in a cruoibJe
vTihlsLrhiur ^^"^'^^ ^"'^ covered w,>h charcoal powder. The result was a
pxpeile4. itass. ihat had fjeen well fused, and resembled what metal-r

lurgists call lead matt Tliere was in it no lead united to-
gether, but some parts of the button were merely a little
ductile. By analysis I found, that about three fiftl)s of the
;^03s -27 from gulphur still remained. Part of the loss it had experienced
fi2aS)i7" ^''' ^y ^'^^ action of the lire, which was 27 per cent, I ascribed to
the vplatizatipn of a portion of the suiphuret; for that owing
^p the separation of the sulphur could not have exceeded G
per cent at most.

Galena then is but yery imperfectly decomposed by heat.
I shall npt speak particularly of tlie sulphurets of zinc,
antimony, &c., because I am npt acquainted with any expe*
riments sufficient to determine with certainty the eiTects,
that heat produce^ on them : but I am led to believe froa^
analogy, that it does not decompose them completely.
Heat alone All the facts I have adduced appear to me to evince, that

ihen expels ^^e action of .caloric a:lone on metallic sulphurets, and par-
but little oi the _ ^ .

sulphur. ticulurly pn those of iron, copper, and lead, is limited to

%he taking from them a small portipn of the sulphur con?

t.ained, an4 aftejrwg^rd fusing and even volatilizing them,

Sect. 11.

Of the simultaneous action of heat and air on metallic sul'
phineis. '

Roasting by That metallurgical process, thp object of which is the de-

the joint action
of heat and air.

the iomt action gulphuration of metals, is known by the name of roasting.

Most authors, who have treated of it, seem to Consider ca-
loric as the sole agent in" the decomposition ; and even those
who have remavked the influence of the air, since the esta*-
blishment of- the new chemical theory, have not considerecJ

^ . , it as essential. The experiments 1 have collected having^

Oxigen has a • : , ^ * ^ . ^^

great share iu ^hpwn tiie insufficiency of heat alone to decompose a metal-
^^' lie suiphuret, the oxigen of the air must be considered as

having a g'reater ^hare in the desulphuration of metals by-
toasting. The affinities both of sulphur and metalHc sub-
stances for this principle render it very probable ; and it i^
likewise proved by the chemical examination of the product^

■'■■•-■-■ '■• ■ . . • ^ . ■ '• '-^^

©ESUI>5IIURATI0N OF METAXS. £tOI

of all roaslincrs, sis well as by the manner in which the prOf
.cess is conclnrtcd. In the roasting- of snlphurets, instead
of seeino' the volatilization of the sulphur effected by a mo-
<derate and long continued heat, we find a sulphuret decom-
posed by the simultaneous action of caloric and air : and
the acknowledj^ed necessity of not fusing the ore, instead of The ore must
iirising from the fear of communicating to it by liquefaction "^^^f^!j^J^2^'^
a cohesive force capable of resisting the separation of the
^sulphur, will be ascribed more simply to this circmnstance,
that s:i(h a state will confine the action of the air to a sur-
face that cannot be renewed, and will soon be covered with -
A metallic oxide. The combination of oxigen with the ele-
ments of sulphurets gives rise to oxides and acids, the affi-
nities of which have great influence on the separation of the
sulphur, and the results of roasting; which are commonly a
jnixture of an oxide, a sulphate, and undecora posed 5ul-
phmet. I shall now examine more particularly and sepa-
rately the roasting of sevei*al kinds of sulphurets, because
the nature of the metal greatly modifies the results; and I
^hall afterward point out how the sulphur is separated, and
in what form.

Roasting of copper pyrites.

Pieces of pyritous copper are laid on billets of wood in Co])per py-
the most convenient manner for the combustion to continue '^'^^'^*
^ long time. The first heat separates part of the sulphur. Sulphur rises,
which is in some degree sublimed, and may be collected ;
but afterward it becomes the combustible, that serves by bums,
burning to continue the operation; and sulphurous acid is sulphurous
dksengtiged, the elasticity of which, being augmented by acid flies oft,
the increase of temperature, prevents its combiimtion with
the metallic "oxides. The sulphuric acid, tliat is formed ^^'-'ph ate of

notwithstandi'igthe care taken to moderate the combustion, ^^i^P'^^f^^^^ed,

'^^ , ^ , ' ana ot iron

unites with the oxides of iron and copper, but the sulphate which is agaih
of iron is in part decomposed by the superoxidation of the "^ P^rt decora-
metal.

Iron pyrites subjected to the same operation will undergo Iron pyrites.
similar decompositions in the same order.

The roasting of cupreoug pyrites in the revcrberatory fur* Copper pyrites
nape gives rise to the same phenomena, and mi«ht be sup- rator*^ T^^*^^^^

posed

O0O DESUI.PHURATIQN OF METALS.

posed to allow a much more complete separation of the sul-
phur than that conducted in the open air. If it do not, tliis
no doiibt is owing to the difficulty of preventing the agglu-
tination of the sulphuret produced by the elevation of tem-
perature arising from the rapid and unavoidable combustion
of a large quantity of sulphur,
ywrnace at j^ reujains for me to speak of a furnace, in which both

the smeltmg and roastmg or the pyntous copper, to a cer-
tain point, are effected at the same time. It is used at Fah-
lun in Sweden. This has an interior crucible, which receives
the product of a smelting of 24 or 48 hours, and in which a
separation, or rather combustion, of the sulphur is effect-
Blast of airdi- €'d. A stream of air from the bellows is made to blow on

Tected on the ^]^g melted mass with such force, as to drive off the scoriae,
metal.

and burn a part of the sulphur that is found on the surface.

The iron is thus oxided, and quartz is added to vitrify it in

proportion as the roasting goes on. This process is perhaps

the only one, in which sulphur and iron are separated «in so

large a quantity at the same time.

"Progress of de- The desulphuration of pyritous copper by roasting ap-

^ulphuration. pears to me to be effected, 1st, by the sublimation of a small

portion of sulyjhur, which may either be collected, or burned

in the air: 2dly, by the disengagement of sulphurous acid,

which is the more abundant in proportion as the process is

well managed: 3dly, by the vaporization of a little sulphuric

acid, the greater part of which however remains united with

the copper.

RoasliTi^ of galena.

Sulphuret of Galena is very difficult to desulphurate completely by
lead. roasting. The affinity of its component parts for oxigen, it

is true, renders their separation sufficiently speedy ; but that
of the new compounds, sulphuric acid and "oxide of lead,
<nves rise to a new combination, which retains the sulphur,
and thus forms an obstacle to the desulphuration. To this
affinity of the oxide of lead for sulphuric acid must be
ascnbed the faciHty, with which this acid is foriried in the
roasting of galena.' \

I shall analyse in detail the various processes, to which
this import«At decornpo6ition has given birth, because I con-
ceive

DESULPnuftATION OF METAJ-S. 20S

celve I fan account for the numerous and complicated phe-
nomena they exhibit.

Whatever care be taken to roast t^alena in a roasting test, In the small
It is impossible to convert the whole of the sulphur into sul- ^^i^Ja^^foJln*^
phurous acid, and avoid the formation of sulphuric. The
resrlt always exhibits a mixture of oxide and sulphate of
lead.

In roastings in the large way, on hearths prepared for the In the large
purpose, the proportion of sulphate of lead is still more ^^^5' st»ll more,
considerable, being in the ratio of the temperature, and the
facility with which the air pervades the ore. Numerous ana-
lyses made in the School of Mines lead me to believe, that
the roasted ore of the mines at Pezey contains from a third
to half its weight of sulphate of lead ; whence it follows,
that, even supposing the whole of the galena to have been -^

decomposed, the roasting has not separated half the sulphur
it contained.

The reverberatory furnace is employed with great success In the reverbc-
to roast ores of sulphuretted lead. In some works indeed, '■^^°''>' t^rnace
as at Poullaouen, such a complete separation of the sulphur a complete se-
is accomplished in this furnace, that, when the roasting is P^Y'\^'«n ^'f the

' , . . o sulphur may

judged to be finished, nothing more than the addition of be effected.

charcoal is requisite, to obtain directly a large quantity of
metallic lead. It cannot be doubted however, but a great Yetsulphatei5
deal of sulphate of lead is formed, which, as we have seen, **^'""^^""
is a necessary result of the action of air on galena subjected
to a high temperature : besides, the chimneys of the fur-
naces are filled with it. The decomposition of this sulphate
by the charcoal produces a sulphuret, or lead matt, and
though sulphurous acid may be evolved, it is very difficult
to explain how the addition of charcoal causes the lead to ^

flow immediately in considerable quantity. I have imagined
that the sulphate of lead was decomposed during the roast'-
ing; and that after this operation nothing remained but an
oxide very little mixed : and I think I have found the cause
©f this decomposition in the action of the galena still unde-
composed on the sulphate formed. The following experi-
ments will make known the nature and result of this action.

Into a retort I put a mixture of one part of powdered sul- Sulphuret 1
phuret of lead and three of sulphate; which at first I heated J^ef^'^'^^^^j^t*

slowly,

i2.04 DESULPHURATION OF METAI.S.

ed together in filrtwly. When the retort was redhot, a pretty considerable

p retort, quantity of sulphurous acid gas was evolved; and this conr

tinned for an hoyr, at the expiration of whicli the retort

The result a began to melt. The residuum had been fused, and wa»

^'T'ViT ^^^^'^ to be a mixture of oxide and sulphate of lead. I
Jd;. & sulphate. . , . ^ .

satisfied myself, that the sulphurous acid, which had been

received into water, was not mixed with any sulphuric.

The sulphate This experiment proves the possibility of the decomposi-

^ecomposed ^j^^^ ^f ^j^^ Sulphate of lead by the sulphuret ; or rather that

by the sulphu- c ^ l

ret. of the sulphuric ^cid it contains by the sulphur and lead of

the galena. The sulphurous acid arises no doubt equally

from the oxigenation of the sulphur, and the semidecom-

position of the acid ; for I convinced myself, that the re»ir

Equal parts duum contains no sulphate. I repeated the process with

*^?h^*^^^^"^ equal parts of galena in sulphate, when the evolution of
sulphurous acid was still more abundant, and what remained
in the retort was a mixture of oxide and sulphuret. Hence I
concluded, that, if tlie proportion of sulphuret of lead were
too small in the former experiment, it w^as too large in this*
I made also an attempt to ascertain more nearly the propor-
tions, that would exactly effect the mutual decomposition ;
and at the same time I endeavoured to satisfy myself of the
oxidation of the lead contained in the galena in the metallic
state.

14 parts to 8. With this view I put 14 gram, of sulphate and 8 of sul-
phuret, well mixed together, into a crucible, not lined,
which I suffered to grow redhot undisturbed. I observed.

Sulphurous that a considerable ebullition took place, occasioned by the
evolution of sulphurous acid; and I did not withdraw the
crucible, till the matter was in quiet fusion. When cold I

Result, sul- found two distinct substances; one, which was at the bottom,

^tasroHead ^'^nsisted entirely of sulphuret of lead, that had been fused,
without any mixture of ductile lead ; the other exhibited all
the characters of the oxide called glass of lead, and was 4
compound of oxide and silex from the crucible, without any
indication of sulphate of lead.

This experiment convinced me, that the le£^d of the ga-
lena had been oxided at the expense of the sulphuric acid :
but it did not show the quantity of galena necessary for the

Sulphuret 1 complete decomposition of the sulphate. I believe, how-
ever.

DESULPHURATION OF METALS. £05

ever, tlmt the pi-oportion of one part of galena to two of sul- sulpliate 2

1 T 1 1 -1 •. j-rr would produce

phate will be very near the mark ; and besides it ditters ^ decomposi-
littie from what a calculation of their component parts t^^/^-
would indicate.

The followiiiir are the natural consequences of these facts : Conclusions^.
], Galena and sulphate of lead mutually decompose each
other at a high heat. 2, This decomposition gives rise to the
formation and evolution of a large quantity of sulphurous
ax'id, and consequently to the separation of a considerable
portion of the sulphur contained in the ore. 3, The result
is oxide of lead, when the proportions are suitable; and
when. otherwise a mixture of oxide and sulphate, or oxide
? and galena.

>. .^ The application of these consequences to the roastinar of ''^^^^''5^ ^^ ,
■ , r. 1 1 • 1 1 n • T roasting galea*

sulphuret ot lead in the reverberatory furnace is easy. 1 in the reverbe^

shall explain the theory of this process in the manner in ratory furnace*
which I conceive it. The powdered galena, or washed ore
. of lead, spread on the bottom of the furnace to the thickness
of a few inches, the upper part of which is exposed to the
action of the air, gives rise to the phenomena we have ob-
served in ordinary roastings. The heat vaporizes a little sul- ^
phur: the air converts part of that on which it acts into sul-
phurous acid, which is evolved, and another more consic^^ra-
* ble into sulphuric acid, which combines with the lead oxided
at the same time. The ore is stirred : the sulphate of lead
mixes witk that which is not decomposed, and their mutual
decomposition produces sulphurous acid : the fresh surface
reproduces sulphate, which serves to occasion a fresh extri^*
-cation of giis, and thus to continue the desulphuration,
which is limited only by the complete decomposition of the
galena. If the process have been well managed, and too
much sulphate of lead has not been formed, the result of the
roasting will be almost pure oxide of lead : if the contrary,
some sulphate may remain, which the charcoal will reduce to
the state of sulphuret, and the decomposition of which will
be ejected in the same way as that of so much galena,
Jlence we may learn the importance of not fusing the sul-
phuret of lead subjected to the process of roasting; for the
action of the air on the fused ore would soon be rendered
null by the formation of oxide of lead which would cover it,

and f

£05 l>ESULPHUrvATlON OF METALS.

ond as the sulphate of lead could uo longer mix with tlic
galena, there would be mo way oj desulphurating it.
*rhis the n>ost The roasting- of galena in the reverberatory furnace then is^
sulnliu ration. i"educed to the conversion of the sulphur it contains into
sulphurous acid; and as this is in great measure effected by
the intervention of the sulphate of lead, wiiich is coatinually
forming, it admits a more complete clesulphuration than
other processes.
Decomposi- A similar decomposition of the sulphuret of lead by the

Scotch furnace ^^^P^^**^ appears to uie also to take place in the treatment
similar. of lead ores in the Scotch furnace. In Scotland galena i*

roasted and smelted in an uninterrilpted process by means
of coal and turf.
TTsed \»ithsuc- The same furnace is employed with success at Pezey for
cess at Pezey. fusi^o- roasted galena containing at least one third of its
weight of sulphate of lead. Its liual result gives no matts,
which proves, that it permits the decomposition of the sul-^
phate, and the separation of the sulphur it contains. I con-
ceive, that the action of the part reduced to the state of sul-
phuret, by the contact of the charcoal, on the undecomposed
sulphate, is one of the principal causes of the desulphur-
ation effected.

In some fiirna- S<mie furnaces have been mentioned, as that of Fahlun

ce">sc:ircely

any effect from and the Scotch, in which metallic sulphurets undergo a real

roasting. roasting; but there are others, in vvhich this effect is scarcely-

sensible. Some reflections on their differences in this res-
pect will probably not be out of place here ; and they will be
the more interesting, as they are intimately connected with
our subject, and account for phenomena, which are inexpli-
cable according to the idea generally entertained of roasting.
the higher the . It is a fact well known in smelting houses, that the highest
le Tsui \uir ftnnaces are least favourable to desulphuration, or in the
carried off, language of nvetallurgists produce the most noatts. If an
indisputable proof of this were required, I need only say,
that at Pezey I have seen roasted lead ores containing a
great deal of sulphate of lead, which smelted in the Scotch
furnace yielded not matts as the ultimate result, but pro-
duced a large quantity in the fourneau d tnauche [a kind of
|)igh furnace].
Heat alone inr if heat alone could easily and completely decompose me-
effectual. . tallic

DESULPIHTRATION OF METAtS. ' gO/

tallic sulp]uirets,the upper partof lnt>b furnaces would be well
adapted to the roasting of ores ; for, beside that the tempe-
rature there is not too great, the air that comes thither, being
deprived of part of its oxigen, scarcely forms any of those
sulpluites, that oppose the separation of the sulphur. But
th€ fact is the reverse of this, which is to me an additional
proof of the little effect of the action of caloric alone on
these substances. The sulphur is separated, from the sulphu-
rets, as has been seen, in the state of sulphurous acid, and
oxigen is indispensable to its formation. In furnaces of no Advantages of

G^reat heisfht the air that comes into contact with the fresh ^ J^werfur-

. . , nace.

charge of ore still contains a great deal of oxigen, and the

sulphurous acid formed is soon withdrawn from the dis-
oxidiug jaction of the charcoal : but if a small portion be de-
composed, a fresh sulphuret is formed, which is afterward
roasted in the same manner as the ore. In the Scotch fur-
nace for instance, when any matts flow from it, they are im- ^
mediately thrown into the furnace again, and what escaped
decomposition in the first process is decomposed in a second.
In high furnaces on the contrary the ore placed in the upper Disadvantage
part undergoes a very incomplete desulphuration, because ^^^^'^'^^^S^^"
the air coming into contact with it contains but very little
free oxigen ; the sulphurous acid formed in the Interior is far
the greater part decomposed in traversing all the height of
the furnace fdled with coals, and a sulphuret is recomposed ;
this by its gravity tends to descend into the basin, which it
does not reach till after a succession of decompositions ; and
the consequence must be a considerable loss of metal, as in
fact is observed.

All these facts together seem to me to place it beyond These proofs
doubt, that the decomposition of metallic sulphurets j^ '^^^^^"^'^'^>'^^'
roasting is produced by the oxigenatioii of their component
parts, and the sulphur is separated more or less completely ia
the state of sulphurous acid.

Sect. III.
Desulphurdtion of metals independently of the action of the air*

The I'arious affinities of sulphur for different mineral sub- Desulphura-
stances afford means of decomposing certain sulphurets, and tion by electiye
metallurgists have already availed themselves of several with

success.

JJ08 BESULPimRATlON OF METALS.

Requisite con- success. In order that thef decomposition of a metallic sul-
phuret b^ any mineral may constitute the basis of a metal-
lurgical pfocess, it is not sufficient, that the affinity of this
mineral for sulphur be greater than that of the metal : it ijT
farther necessary, beside the conditions economy requires^
that several others indispensable to the success of the process'
be satisfied, which greatly diminishes the number of ag'ent^
iudicated by chemistry. For example, if the sulphuret re-
fiultintr from the decomposition be infusible, or nearly so;
or if it have the property of combining with the metal to be
V separated, or witli the sulphuret yet undecom posed ; it is
obvious, that the object sought, which is the separation of
the metal, will not be obtained. Hitherto scarcely any thing.
but lime and iron has been employed.

Desulphuration of mefcury.

Sulphuret of The sulphufet of mercury is easily decomposed. It is

Jnercury by sufficient to present to the sulphur a substance capable of
lime or iron. . . . , , , t >•,• i i

retammg it, and the mercury may be volatilized alone.

Thus iron and lime are erriployed singly or conjointly in the

treatment of cinnabarine ores.

Desulphuration of copper.
Cojjper pyrites Copper pyrites afe smelted in some works with lime,
hy lime. either in the fourneau a mancfie^ or the reverberatory fur-

nace; but this process is not sufficiently known in detail, to'
enable us to judge of the efficacy of this agent.
tran tfoes not ^ ^*^^^ thought with some metallurgists, that tlie acknow-
answer. ledged greater affinity of i ron than of copper for sulphur might

occasion the decomposition of sulphnret of copper by this
metal, at least in some cases : but the experiments lam about
to give induced ^ne to relinquish this opinion.
Experiment in ^^t E.vp. I mixed 10 gram. {155 grs.] of pyritous copper,
proof. the composition of which 1 knew, with 4'3 gram. [66 grs.] of

iron filings ; put the mixture into a crucible ; covered it with
charcoal powder ; and heated it in a forge fire three quarters
of an liour. The proportion of iron was calculated so as to
be sufficient for taking up all the sulphur combined with
the copper in the ore en>ployed. In the crucible I found a
perfectly homogeneous mass, weighing 13*1 gram. [202 grs],
which dlid not contain the least globule of metallic copper,

nor

DESULP«tjRATION OF lilETALS. 209

or any sign of ?'eparatioti between the sulphuret of iron and
that of copper*.
' QdExp, Another trial was made with 10 gram. [155 grs] 2d experimetit.

of pyiitous copper and 5 gram. [77 g's] of the same mineral
roasted, which is nearly the state of the product when the
ore or matts have not been completely desulphurated. The
proportion of iron was still insufficient to separjite any cop-
per, of which there was abundance in the mixture. I heated
it three quarters of an hour, and found, as in the preceding
experiment, a homogeneous mass, without any sign of me-^
tallic copper, or pure sulphuret of copper : it was a tru6
coppfer matt.

3d Exp. Equal pJirts of crude and roasted copper py- Sdexperimeat.
rites were mixed, moistened with olive oil, and heated
strongly for half an hour in a crucible lined with charcoal,;
The product was nothing but a powder, that had not un-
dergone airiy fusion, no doubt owing to the superabundance
of iron.

These few trials I conceive are sufficient to prove, that th^ Iron, sulphur,
desulphuration of copper by means of iron will always be fr^m^a^tri^^le
f eiy difficult to effect, because a triple compound of sulphur, compound in
iron, and copper, is formed, or a combination tak,es place be- fj^^^^°^*^^*
tween the sulphurets of copper andiron, which obstructs the
Aeparatiou of the copper.

Desulphurhtion of galena.

Galena is one of those sulphurets, in which this decom- Sulphuret of
positioii is most readily effected; The fusibility of lead,
which facilitates the union of its particles, as Well as the little
affinity it has for sulphur, are the cailses of the Success of the
attempts of this kind. Lime and iron are employed in dif- by lime and
ferent circumstances for the desulphu ration of galena* The ^'■^'^-
use of lime is not very general, and it is impossible to judge Lime httle
of its effects from wl.at is known of the properties of sulphu-
ret of hme. The treatment of galena by malleable or cast iron pr^f^rsK*
iron in small pieces is more in use, and appears very advan- ble.
tageous.

* In the decomposition of galena by iron, when the latter, is ill toa
*mall quantity, three distanct substances may be observed : lead, sulphu-?
ret of lead, and lastly sulphuret of iron at the upper part.

Vol. XVI—Nov. IS07. P At

210 GEOLOGICAL OBSERVATIONS IN FRANCE.

Experiments ^t tlie school of mines of Montblanc a ffreat many expe-
at the School . ^ , , . , , , , . „

jj nments nave been made on the desulphuration of galena by-

iron, the results of which were of sufficient importance, to
render the publication of them desirable.
Hints may he The Drcsent paper contains several facts applicable to the
facish^'^^"*^^^^*^*^^ metallurj^y, and capable of sugj^esting different ex-
given, periments to those who cultivate it. I have not pointed out
any, because they wilT readily suggest themselves to those,
who are capable of conducting them.
Mr. Descotils AH the experimental researches here given were made in
th3 «cpS-^ ^^® laboratory of the Council of Mines, and under the eye
meats. of Mr. Descotils, whose advice was of great advantage to
me, in giving them that accuracy, which he is accustomed
to observe even in the least operations.

VII.

Heights of various Places determined hy the Barometer, in
the Course of several Tours through France, Switzerland,
and Italy: 6^ F. Berger, M. D.y of Geneva*.

Ascertauiing JtSlMONG the means best calculated to advance the phj*-
heights o^^^ ^^ gj^^l department of geography in the present state of our
the improve- knowledge we may reckon the ascertainment of the eleva-
ment of geolo- ^j^^j^ of a great number of points on the Earth's surface.
La Place The learned author of la Mecanique celeste has proposed to

employ with this view observations with the barometer con-
jointly with the longitude and latitude, to obtain a more
complete and extensive levelling than trigonometrical mea-
surement will admit, and at the same time to acquire a
knowledge of the direction of mountainous chains, the slope
* of rivulets, and the forms of countries. To promote these
useful objects I shall add to the researches of these natural
philosophers, who have attended to this branch of physics*
the observations I have collected in different journies. They
will form the subject of a f'ewpapers, which I shall publish

i * Abridged from the Journal de Physique, vol. LXlV, p. 220, March,
1807.

CEOLOGtCAt OBSERVATIONS IN FRANCE. 211

in Succession, and in which I shall point out generally the

n^iire of the' countries mentioned, that ray labour^ may be

more immediately useful to geoloj^y.

All the heisi:hts were calculated according to the formulae Hcic^hts calcu-

o? Messrs. de Luc and Trembley: not that I mean to speak l<ited according

•^ . ' . to de Luc and

of them as the only ones (it for practice ; I know there is a Trembley.

method founded on different principles^ which was proposed
some years ago by a learned philosopher, and has a just
claim to oiir best attention : but my labours were in great
measure completed, before I was acquainted with it, so
that it would have been too laborious a task, to begin them
anew.

They who have at heart the improvement of measuring Modes of as--
heights by the barometer however would do well, to calcu- hdtrhts by the
late their observatioiis according to different formultE, for on barometer
this point the result of experience is chiefly to be considered, p^red wkh°tri-
and we have not yet a sufficient number of decisive facts, to gonometrical
induce us to employ one formula or method exclusively of '^^'^^ ations;
every other. It is desirable that some philosopher, residing
in the neighbourhood of a solitary mountain, should mea-
sure it trigonometrically with great exactness, and afterward
r-epeatedly ascertain its height by the barometer, calculating
his observations according to several formulae, and com par-*
ing their results with his geoinetrical n;ieasurement. It is and tried at ya-
particularly important, that these observations should be "*^"s seasoiis
made at all seasons of the year, and at different times of the ti^es brth^
cliiy, so as to take in every variation of temperature: but in ^^y.
reality when mountains of moderate height are visited, we
■generally find on them the same degree of temperature, and
most frequently that at which the various formulae give near-
ly the same results. We ought not to suppose therefore,
that the science has already attained such a degree of per-
fection, as to enable us to dispense with farther trials: the
only course to be followed appears to me to be that of tz^pe-
rience.

The nec€ft!»ity of employiiSg good instruments is too ob-
vious to mention. It is likewise to be wished that th.e tra- When calculi*.

veller, into whose views it may not ciiler to give heights with ^^^"'' ^""^ m^dc

, ,..,„'? jn a loose way,

any great precision, as the geologist m general. for instance, this should be

V. on Id appiise us of this. It would farther be of advantage, mentioned.

P 2 ' when

212 GEOLOGICAL OBSERVATIONS IK FRANCE.

when accurate barometrical measuremeuts are published, to
mention the hour of the day when they were made ; and at
the same time the measurements of other travellers, liowever
diiJerent they may be from our own, with the formulae they
employed if possible. Thus useful materials would be stored
up for the promotion of science.

The following observations are classed according to the
journies in which they were made; and in them I have coii*
formed as much as possible to the rules I have laid down,

S^ct. L

Tour through Heights ascertained during a tonr made in the ci-devant prcH
Nonnaiidy. vinces of Picardy and Normandy,

This tour was made toward the end of the summer of
1803, in company with my friends and colleagues Messrs^
Its leading ob- Jurine and de la Roche. I set off from Paris with intention
jects. ^Q follow tlie seacoast as much as possible, to examine the

structure of the shores, and the different elevations of the
cliffs. I used a siphon barometer made by Diimotier, which
however I did not think sufficiently accurate to allow me
to consider my results in any other light than, simply geolo-
gical.
Chalk soil in- It is Well known, that part of the soil of France, pro-
terspersed with ceeding in a north-west direction from Champagne to the
borders of the sea, is composed of chalk, which continues
as far as England, and includes flints of irregular form, se-
parate from each other, but arranged in parallel beds, more
or less distant, which alternate with the chalk. Beauvais,
Amiens, &c., are in this line. On the left banlc of the
Somme, below Amiens, ore little hills of no great height
formed of this chalk, which is burned for lime. At Pic-
quigny there is very good peat.

At St. Valery on the Somme the cjiff is not above 6o or
Stratum of ^^ feet high. The chalk is in ])orizontal strata, a foot and
flints, which half thick, between which is a very thin bank of flints,
out torm\he The^e flints, separated and rounded by the waves of the sea,
pebbles on the appear to compose the pebbles that are found at the mouth
of the river. At Crotoy, a town formerly fortified, and
built on the right bank of the Somme at its mouth, the cliff

no

GEOLOGICAL OBSERVATIONS IN FRANC^. Ql^

no longer exists, and we find only a white quartzose sand, White quartz
forming downs of litile height followin;^- the direction of the ^^."^»
coast toward St. Quentin. The same sand is seen all along
the coast from St. Valery to Cayeux, and even to the envi-
rons of the town of Ault. This alluvion therefore, if it have
been produced by the Somme, occupies a space of at least 7

or 8 lea^rues flS or 20 railesl. Is it not rather owinoj to the perhaps left by

"_,'-. -* o the retreat of

retreat ot the sea r tlie sea.

Near the town of Ault the pebbles are so accumulated on y xtea./ive bed
the borders of the sea, that they extend above, a mile in- ^'^'i^-bblesm-
land. r found there a flint passing to the state of caUe-
dony. At this town the cliffs reappear, still exliibiting the
same structure. At the city of Eu there is an interruption
of the cliffs, whicji appear again at Treport with the same
character.

From Crlel to Dieppe the soil is essentially sandy. This Sandy soil.

town is in a bottom, through which the river Arques flows:

and it is these valleys, watered by so many different rivers. Cliffs inter«

the course of which in general approaches more or less aruptedbyri*

" ' ^ vers,

west-north-westerly direction, that the continuity of the

cliffs is interrupted. From Fecamp to Havre, the country

being less intersected by them, the cliffs are more conii-

nuous.

At cape de la Heve, about a mile and a quarter north-
noi-th-west of Havre, the cliff" is not so abrupt as at Aull
^!id Treport ; in other respects its striictu*-e is nearly the
same. At the bottom, toward the village of St. Adre^se, a
bank of marie is found, of which bricks are made: and the Marie,
cha>k rock includes different kinds of petrifactions, as well petrifactions
as flints, and nodules of pyrites, which are decompos;ed by '"'^d pyntes in
oxidation when exposed to the air. The cliff is continued
up the course of the Seine : and at Orcher, a pleaisant vil-
lage 3 leagues [7|- miles] east of Havre, it is about 200 feet
high. Here it is more abrupt than at cape de la Heve, and Sandstone un-
about a tifteenth part at the bottom is composed of a sand7 d^' ^'•
stone with small siliceous pebbles.

At Honfleur the cliff ceases to contain strata of flint, and prij^ts cea^e.
diminishes in heig!,t as it approaches the mouth of the
Toucques, 4 leagues [10 miles] farther. From Tronville
§ar mer to within 4 miles of the mouth of the Dives it al-
most

214

GfOLOQICAL OBSERVATIONS IN FRANCS.

Sand,

Caen river
building stone.

Reddish, most whoUy disappears. A reddish, shelly calcareous stone

stone/ is very abundant' on the shore. Imperceptibly the clitT rises

again, and opposite the rocks called the l5Uick Cows it is

Blue marie in- about 150 feet high, about two thirds of the lower part, be-

cludiug fossil . 1 I • 1 1 • 1 1 1 • /■ r 1

she\!s and '"g a blueish marie, include a large species ot tossjl oyster,

traces of bitu- called the crested oyster, other petrifactions, and signs of bi-
miai-ied wood. ^ ... , n i ^ • i n

tuminized wood. 1 he upper part is chalk.

From Dives to Savenelles, or Sallenelles, at the mouth of
the Orne, nothing appears but sand, forming in some places
downs. On proceeding up the Orne, .near a mile and half
beyond Savenelles, arc quarries of a large grained cakarecnis
stone, soiled with yellow earth, lying in horizontal strat.T,
and used for building in the country round.

From Gray, at the mouth of the Seule, no cliff is seen
till we come to Tracy, a village 8 or 10 miles to the west-
CUffof blueish south-west. There it is about 200 feet high ; and is formed
ireestoue. ^^ ^ ^^^y. fine grained bluoish freestone, tolerably hard, in-
terspersed with scah^s of mica, lying in horizontal strata, and
including a prodisious quantity of cornua Ammonis, some of
which are very large. The whole of this coast abounds in
fuel and other marinj plants.

The sum.' calcareous freestone forms the substratum of the
soil from -BayouK to Littry, a village 5 miles to the south-
west. At Litt-r\ is a coalpit, that deserves the attention of
the naturalist. It was opened in 174-1, and has two shafts,
-one of v.hich, called St. George's, is 343 feet [36'8 Eng.]
deep, and has several extensive galleries issuing from it. The
thickness of the coal varies from 4^ to 9 feet [4 feet 10 in.
to 9 feet 7 in.] : it lies on a browni.sh calcareous freestone,
but It tie effervescent ; and this an a clay, very soft to the
touch, and not attackable by acids. At 250 feet [267 Eng.]
from the surface occurs a stratum of a- primitive congluti-
nated stone, composed of siliceous pebbles generally an inch
or tv'o in liiameter, nodules of steatite, and thin laminae of
coal, cemented by a finer freestone, which does not effer-
vesce with acids. , No petrifaction has yet been found in this
coal mine, except one branch of a tree, in which traces of
woody fibres are perceptible. The coal is in general very
sulphurous ; that of the best miality is sold on the S|)ol (or,

^Q^.

Cornua Am-
m^iiiis.

Fuci.

Coalpit.

GEOLOGICAL OBSERVATIONS IN FRANCE. Q\;^

$6s. [13cl,] the bushel, \ypighing about 130 lbs; and the

worst fetches 15s. [Zftl.l. The water of a well 18 feet deep, Water at the

. . r c. r-y > i r. r '^ f • bottom free7.es

at the bottom of St. George s shaft, freezes on its surface in j„ wmcr.

winter. On the 27th of. September Deluc's thernpomeler Cokl greater

stood there at 12'8 fSO'S F.l, while in the open air it was tliani" the

V -* ' open air.

at 17-6 [7V6 F.]. The water of this well is extremely

acid.

'J'he Vire, which falls into the sea not far from Isigny, forms Sand bank.
a considerable bank of sand at its mouth. There is no ap-
pearance of cliff here; but at Vierville, a small town on its
left bank, and not far from the sea, there are some traces,
which soon give way to the sands and downs, that extend to

Ravenoville 7^ miles N. N. VV. Throughout this space an Shells and zos-

r I 11 r 11-1 11 1 tera marina

immense quantity of shells are found, which are collected ^g^.^! ^s ma- "

and sold to the farmers for dressing their grass land. The nure.
zostera marina, which covers the shore, is collected for the
same purpose. Thc^ rudiments of cliff seen at Vierville con-
sist of horizontal strata of free stone, alternating with clay ;
Voth including many petrifactions, particularly gpyphites and
ammites.

At Ravenoville, which lies opposite the isles of St. Mar- Petrosilex,
couf, we enter at once upon the primitive class of stones. A
beautiful kind of reddish scaly petrosilex forms the transi-
tion from the primitive substratum of the peninsula of Cher-
bourg to the shelly calcareous stone of the surrounding coun-
try. The houses of the neighbouring villages, as well as the
forts on the coast of la Hougue, are built with this petro-
silex.

The islands of St. Marconf are probably of a similar rock,
since the corresponding coasts of England are; so that, as Granite proba-

Mr. Delametherie observes, we can scarcely doubt, that the ^^^ extends

1 r • I ' t I • 1 ' /. 1 1 1 under the sea

granite extends far into the sea on both sides ol the channel : acoss the
and if it were ever to be laid drx', we should probably find channel,
the continuation of the gmnitic chain from one country to the
other; or at least they would be separated Vonly By a few
plains of secondary formation, as are the granites of Biitanny
and what was formerly Limousin.

Ravenoville is perhaps the most northerly place in France, Salt pans^
where salt is made byimitating to a certain point the pro-

216 GEOLOGICAL OBSERVATIONS IN FRANCE.

■ •>, - ■ .... ,,

cess of salt marshes; the tide flowing into basins formed in
the sand, where the \yater standi some time to evaporate be-
fore it is boiled down.

The cliffs do not reappear as far as fort de la Ilougue,
where I was obliged to give up my design of doubling cape
Barfleur, viewing the real granite in its native situation. A
idisngrecable event, which it would be useless to mention,
obliged me to proceed directly to Valogne. On this road I

Schist. continually met vyith argillaceous schist, which as it proceeds

in land forms a series of woody hills, rising in height as they

Furze sown to recede from the coast. Near Valogne the ulex EjiropceuSf

manure. furze, is seen in abundance. It is sown there, to be burned

on the land as a manure.

Woody coun- From Valogne to Cherbourg the country is w-oody, and the
^' soil re<]dish. Cherbourg is built on a substratum of light

Steatite. ^rcen steatite, very greasy to the feel, in laniinse more or less

Curved. In some places they are in separate pieces, coarse

ITarbourof grained, and easily broken. The new basins for the harbour
ler ourg. ^^^ Cutting out of this rock. Large nodules of true granite,
and veins of quartz, are included in the' steatite.

The mountain of Roule, a little to the south-south-east of
Cherbourg, may be considered as constituting the cliff. Ij;
terminates abruptly toward the town in a precipice about 4Q

Petrosilex. toises htgh. It consi'^ts of a kind of dull petrosilex, with a

shelly fracture, in some places reddish, in others whitish,

much like that of Ravenoville, but evidently in strata seve^

ral feet thick, all rupning S S. E. and N. N. W. Quartz

Quarried for crystals are occasionally found in it. This rock is wrought
the haroour of - , , _ , , , , ,, , • i *

Cherbourg. i^r the works of the harbour, be.ng blasted in large masses.

Hilly pcuntry. Between Cherbourg and St. Lo the soil is variable. Thence

to Aulnay and on to Falaise it is hilly, and woody, but the

trees are in general low. The usual direction of these hills

is noith and south, and they diminish \n height as they ap--

Schist. proach the coa*it. They consist of a micaceous argillaceous

schist, which does not effervesce with acids, and includes no

ciganic bodies. In some places it passes into true slate.

Limestone '^^»r Villers hbv^^eyier, in the Hlstrici of Cam, is found a gra-

Cattlefed on ^'"^"^s limestone containing a prodigious quaiitity of belem-

furve; - '' nhes. Tiic lurze on the downs is employed for feeding cattle.

The

GEOLOGICAj:. OBSERVATIONS IN FRANCE. 31/

I'he country on the right bank of the Orne begins to differ Limestonf

perceptibly from that on the left. At Ussy 10 or 11 miles

N. N. VV. of Falaise, limestone occurs in strata. The course

of the Orne indeed appears the boundary of two different

jkinds of country : on the left bank we find micaceous argil- divided from

laceous schist, and on the right limestone. The argillaceous thebctiitbf

. the Orne,

schi^t of the woody part of Normandy may be considered as

forming the transition to the primitive rork, that constitutes
ihe most advanced part of the peninsula of Cherbourg to the
N. N. W. At Veriieuil nodules of flint reappear in the Flinty challc. '
chalk, and we begin to perceive vineyards. The line traced * '^ y^
by Mr. Arthur Young on this point appears to me very ac-
curate.

Thus we see, 1st, that the part of France where we find a Extent of tli-i«
chalky soil interspersed with flints stretches S. E. and N. VV., ^^^^•
and is pretty accurately included between the mouths of the
Seine and fhe Lys, occupying a breadth of about 50 leagues
[125 miles] and a length of 70 [175 miles]: 2dly, that in
this the highest cliffs occur, at Ica.^t among those that are
seen between St. Valery on the Somnie and Cherbourg. The
following table will show this more conspicuously.

Heights above the sea in Table of

faces. toises&thousandih parts. heio-bts above

According According the level of the

to Deluc toTrt'nibley. ^^^*

Beaumont-sur-Oise •• .^.. .•35'352- 39 514

^Amiens*.. f....38'801 3S-977

Frixecourt SO'OOp 30'321

Ault 25-437 26'-100

Treport 59*458 6'0'99O

Etretat 52-944 54*243

Cape de la H^ve 46'"545 47 729

Honflour 41798 42*887

Caumunt 14r32() 143-707

Cahagnes 88*206' 89-13.5

Auinay * 58-61 7 58-913

Harcourt ...-*. 22'672 23'229

yiif.

2lfi JfEW CLASSIFICATION OF INSECTS.

VIIT.

A new Method of Chssing the Hymenopteraiis and Dipterous
Infects: bij L. Jurine, Correspondent of the Institute,
Professor of Anatomiji Sfc*,

H -mcnoDtcra *"" ^^^ distinction of the order fiymenoptera, pointed out
a natural order, by Aristotle, is SO natural, that it has been retained in ev^ery
Genera distin- System of entomology to the present day. Linneus, Geoff
guished arbi- froy, and Degeer, divided it into a few genera, more or less
arbitrary, from various particularities of confirmation : while
Fabricius and Lareilje have attended in this point to the
or b the arts P^^'^® ^^ *^^ mouth. The difficulty of dissecting this organ
of the mouth, however in the smaller species is a great inconvenience; to
which IS diiii- avoid which, and at the same time adhere more closely to the
/ system of classiiication by the wings, Mr. Jurine has recourse"
to the disposition of the principal ribs of the wing for the
generic characters.
New method Having observed, thtit these ribs, by intersecting or termi-
by the ribs of nating in each other, form various reticulations, which are
c vngs. constantly aniibvm in insects of the same kind, he has stu-
died these systematically, and given aci-'urate representations
of those of the hymenoptera in 14 coloured plates, included
in a quarto volume, in which he details his method. On the
outer edge of the upper or larger wing of the hymenoptera
are two large parallel ribs, appearing to issue from the corse-
let, and strongly united by an expansion of the membrane.
The outermost of these he terms the radi a f r'lh, the inner-
most the aihifdL The phice where they terminate toward
the end of the wing, which is commonly distinguished by a
?':ot or mark more or le'ss deep, he calls the pointy or carpus.
The rib that proceeds f'om this point to the extremity of
the wing has a membranous' space between it and the outer
edge of tlie wing, forming one or more areas, whiph he names
Tudtal celts. From the extremity CTf the cu'uital rib, and near
the carpus, another -prominent line proceeds towards the ex-
tremity of the wing, and the interval between this and the

* Abri tged frorri tlie Magazhi Eucycloptdio^ue for April, 1807, p. 434.

preceding

PLOTTING QUADRANT, LEVEL, AND CALCULATOR, «i]g,

^recedhit^ is the cubital cell, which is commonly divided into
two, three, or lour.

All these cells exhibit a g-eat many differences : thus they
are iiicouipieie, appea liculdte,'petiolate, &c. These difFer-
encCv-i coiist.tute the. characters.

Tt e whole of the hyraenoptera with which Mr. Jurfne is DiYided into »
^aoquuinted, and his own collection contains 2200 species, he gg^gg^^^* *'^*
.inciu<ie:> in i^iS j^ejiera, which he arranges in three suborders,
didti li^uisiied b the manner in which the abdomen is at-
jtac ed. The vdiptera, arranged according to the i^ame me- Thediptcri
thoa, w 11 siiortly appear. promised.

IX.

Description and Manner of Using Mr, Robert Salmon's
Gf'ometrical Plotting Quadrant^ J^evely and Calculator, for
the Use of JSavigatiun and Land~Survei/ing; ascertaining
inac essible JJistances, aud Demonstrating and JJetermin"
ing vuriou» Problems in Geomtiry and Trigonometry*,

N the instrument and parts thereof are engraved the Terms used.
names given by the inventor, and made use of in these ex-
planations; the base line being that at right angles with the
90 degrees on the arch, as it is also to the perpendicular,
which perpendicular always moves parallel to thejJO degrees.
-For the use of land-surveying, where the instrument can be
made stationary, the sight (mai'ked a. Fig, 1, P/. V.) with
the small hole in it, must be applied; but for sei c?rvicc,
the one h, Pig. 2, with the mirror, must be substituted in its
place.

Every person who has iiad occasion to rlescribe or calculate ^^^t ri<Tlit-rme<l
the parts of the right-lined figures used in geometry, per- ^^g^ire; resoWa-

. ,• V IT 1 ., n ble into ttiaii-

spective, surveymg, navigation, dmlhn^, architecture, &c., ^\^^^

murft have perceived, that all of them are resolvable into the
most simple of figures, a triangle, or some number of them.

Hence the great importance of geometry and trigono- Useoftrlgono-
iuetry.
• The Sftciety of Arts voted Mr. Sahiioii their silver medal and ten
guineas for this invention. See thj.r Tratxs-. Tol XXllI, p. 290, whence
Vn IS article is extracted.

' metry

g20 PLOTTING QUADRANT, LEVEL, AND CALCULATOR,

metry, in teaching, either by construction or calculation, the
knowledge of all the properties or relations between the three
sides and three angles, of which every plane triangle is corn-
Similar trian- P^s^*^' Euclid having demonstrated, in the fourth propo-
fles propro- sition of the sixth book of his Elements, that in any two
tlie'r' "to * similar triangles (by which he means their having the sQm«^
angles, without regard to the actual lengths of their sides,
for one triangle rnay be very small and the other ever so
large) every pair of the corresponding sides in the two trian-
V t* II - ) ^^^ ^^^ proportional ; it is the business of trigonometry to
plied to rectan- solve such problem.s, with the help of the tables of sines and
j^es, tangents, or of sectors, sliding or other rules, and scales, by

which you can find, on inspection, a right-angled triangle,
exactly similar to any given right-angled triangle, (or having
one of its angles equal to 90°) which ca?i be proposed, or can
occur in practice ; and by the Rule of Three we say, as any
side of the tabular triangle is to the similar side, supposed to
be known, of the triani>ie under consideration, so is any
other side of the same tabular triangle, to the corresponding
side supposed to be souo-ht, of the triangle in quesi-ion. It is
_ t V). ^^'^^^'^^' *^^*' hy means of the base line, perpendicular, and

pUcableto either the upper ^ or lower limb of my instrument, by the two
t^esej motions of which the perpendkidar is capable, and the an-

gular motion of which the limbs are capable ; any right-
angled triangle whatsoever, as C B E, or C D E, in the
diagram Fig. 6, P/. V, may be instantly formefl, (by bring- .
ing the top corner of the perpendicular to touch the lirnb)
with the same or greater facility, than it could be taken out
of a trigonometrical table, measured by the compasses on the
sector, or set on any instrument now in use for that purpose.
But no instrument that I have seen or read of is capable of
and ennally to forming immediately ani/ obtnse-ttvgled triangle, as on my
cbiuse angles, geometrical plotting (jvadrant can be done; nor can the tri-
gonometrical tables be applied, to produce the sides and
angles of such a triangle, without some trouble, in any case ;
and in some of the most useful cases in practice, the labour
is very considerable. 1 shall therefore give the solution of
Prob1ems(6be live problems. First, supposing, that Figure 6, PLY,
solved by it. represents my instrument, set to answer-ihis and the follow-
ing problems ; A, B, C, being the triangle under consider-
ation ;

PLOTTtNG <iuAl>RANf, LEVEL, AND CALCULAToiR* ^^J

ation ; then since the Z A C E, is by Euclid (I, 90) equal
to the Z B A C, it is evident that this angle will be shown, or
may be set, by means of the divisions on the arc F G; also,
that since C B E> and I C B, are also eq^ual, the arc H I,'
with the addition of 90*^ (for the angle E B A), will show the
Z C B A, of the triangle ; it is equally evident, that the a7X
F H will show the sum of the two Zs B C A, and AC F, af
the same time that the lengths of alt the sides may be read
off", on the divisions or scales, on C A, C B, and B A.
Therefore :

First, — To construct or set a triangle, having two of its angles
and the side hetioeen them given.
Set the limb C G, to the division at G upon the arc an- to set a triaa-
sweriug to one of tlie angles, say A, and make it fast, then S^® "^ which 2
to this ZA add the (rther given angle, (which we will call C) side between
and set the other limb C H, and make it fast at the division them are glv^,
H, on the arc answering to the sum of their degrees; then on
the limb C G seek the length of the given side C A ; next,
push the perpendicular up or down, till the parallel cuts the
point A, (always observing, the divided edges are those you
Work to), and by the help of the mill-headed nut, move the
perpendicular, till its top corner just touches the limb C H,
say in the point B; when it is evident that the degrees oa
the arc H I, added to 90°, is equal to the angle B, and that
the other sides C B, and B A, may be read orf thereon. Or
supposing C B D 16 be the triangle, whose angles B and C
and side B C are given, we have only to move the limbs so as
to make 1 H equttl to B, and H G equal to C, and then to
bnngthe top of the perpendicular to touch C H, at the divi-*
sion B, answerii'g to the sideSl^ B, when the other Z D will
be shown by the division on the arc G F, adding 90° thereto ;
and the remaining sides C D and B D may be read off on
their respective scales.

Second. — To set a triangle, having fivo sides and iht angle
included between them given.

Let A B C be the triangle, A B aud A C the given sides, T\7o sides and
and A the given angle; iirst set the litnb C G to the division ^^^ ^"g'® ^2- •
answering to A, then bring the parallel up to the point A, any J^Ien.

S52 PLOTTI?JG QUADRANT, LEVEt, AND CATXULATOR/

swering to the side C A, and by the ?/?// move the perpendi^
cular, till B A answers to the given side B A; next bring
down the limb C H to touch B, and on C B mav he read
the other side, while H G will show rbe aiifrle C, and 1 H -f
Q0° the Z B, wlienee all the six parts a,e known.

Third. — To set a triangle^ having two sides and an angle oppO"
sile to one of them given.

Two sides and Let A B C be the triangle, A C and G B the given sides,
an angleoppo- and A the given angle ; first read the angle A on F Gj and
them given! ^^^ ^^'^ ^^^^^ ^ ^ thereto ; then push up the parallel lo the
division at A, answering to C A, and with one hand work the
nvt and with the other move the limb C H, till they touch at
B, the division answering to the side C B ; then B A is the
side sought, and the arc G H will show tlie Z C, and I H +
Q<P the Z B.

Fourth. — To set a triangle, having two angles, and a side op^
pQsite to one of them given.

Two angles Let A B C be the triangle, A and C the given angles^

posite to one of ^"^ ^ ^ ^^^ given side ; first, set F G to the Z A, and G H
ihem given, to the Z C, then pu?h the perpendicular up or down with one
hand, while the other works the nut, till the given side B A,
on the parallel, is applied exactly between the limhs C H,
and C G, then I H + 90' will show the renaaining angle B,
and on C B, and C A, may be read the lengths of those sidesa

Fifthk — To set a triangle ichose three sides are given.

Three sides Let A B C be the triangle ; on the limb C H seek th<?

point B, austvering to the side C B ; then, using one hand

to move the perpendicular, and the other to turn the nut, let

an assistant at the saime time, with his right hand, gently

move the lintff C H, while you cause the top coiner of the

perpendicular aUvays to touch the point B; at the same time

let the assistant move the limb C G with his left hand, tiU

the lerigths of C A, and B A, on their respettive scales, art

found to intersect each other, when F G will show the Z A,

G H the Z C, and H 1 -f 90^ the Z B.

The instru- My solution to the last problem is inferior to the common

co^^eiiient ^'* method of plotting the triangle on paper, and measuring

the

PLOTTING QUADRANT, LEVEL, AND CALCULATOR. ^£5

the angles with a protractor; but I have introduced it here, than tlie com-

1 I - • ' \ ' i_i r 1 • ^i-- n nion method,

to show that my instrument is capable ot solvmgthis, as well

as all other cases of obtuse-angled triangles, and might, by
extending the arc to a semicircle, as shown by the dotted
lines on the figure, solve any triangle. In the practical pro-
blems in surveying, which follow, the triangles can always be
taken right or obtuse angled, and the instrument as at pre-
sent constructed is fully competent. I might here add, that j^jne divided
a given line can readily by my instrument be divided into by it into any
any number of equal parts; ,drq,wings might be enlarged or parts.
diminished, as readily as with the proportional compasses, and
many other equally useful purposes may be effected thereby.

First, — To meamre an inaccessible distance, hy a perpeadicu^
1 27' line set off towards the right hand, /torn the line or base
between the obser per a,ria objector.
Set the base line of the instrument in a Vine pointing to Method of

the object, at the same time place a staff at any distance at measunug aa

, ,.■,,.• , f .1 1 V inaccessible

pleasure, as a perpepdicplar (being 90 degrees irom the base), distance.

On this perpendicular measure, any distance (say 50 yards
or other measuresj as a second station ; move the instruWent
to this distance, and place it with \ts perpend iciilar in the
same line as before; the instrument being so pkced, set the
lower-limb pointing to the object, and with the screw make
the same fast; this done, the distance of the object will be
thus readily known. Raise the moving perpendicular of the
instrument to the division 50 (as before suggested), then with
this height move the same by means of the nul, till the extre^
mity intersects the lower li?nb befove set, at which intersection,
the distance from the second station will be shown ; and on
the base line will also at the same time be seen the distance
from the first station : this is a case of right-angled triangles.
]^ot€, — As the divisions on the perpendicular are denomi-
nated (either feet, yards, poles, or other measures), so will
the distances be indicated on the oXhex limbs, and on the base
of the instruiflient.

Secondly.--— To determine the distances of any two inaccessible
objects, both objects lying in a right line from the observer.

As before directed, place the instrument with its base in 'j.^ moagtire

the the distance ctf

224 PLOTtlNG QUADRANT, LEVEL, AND CALCULATOR.

t#o inaccessi- the line of the objects; th^n by means of the upper Hmh, set

"Lie objects in a ^_„, , -. « ii . ,.

fitlu ikie, ^'^ S^ degrees, place a staft as a perpendicular at any distanct

at pleasure (say 50 as before)^ This done, remove the in-
strument to this second station, and place it so that the
upjy4>r limb fstill at 90^) may be in the siime line as when at
tbe first station ; this done, iriove the upper limb into the di-
rection of the nearest, and the Imver Ihhh into the direction,
of the most distant object; which /i/n^.? being so set, and
inade fast, the distance of both objects from the second sta-*
tion will be seen on the two limbs, and the distance from the
first station a:t th^ same time seen on the base line, by setting;,
and moving the perpendicular as directed in the last case.
This is also a case of right-angled triangles. "

Thirdly. — To measure an inaccessible distance in an oblique^
angle, where a right angle cannot be obtained, by reason of
some impediment on the ground.

To measure an At tlie first station, from which the distance is required,

inaccessible p]ace the instrument; then set up a staff in any attainable

ifHtance in an ^ . i , , ,.

•Mi^ue angle, direction, to any distance at pleasure (the more distant the

better). The instrument being set with its base in direction
to the staff, with one of the moving limbs take the angle of
the object, and with the screw fix it thereto. This done,
move the instrument in the direction of its base (being be-
tween the first station and staff set up] to any certain distance,
(say 50 yards or measures) as a second station. From this
secoftd station again take the angle of the object, and theieto
fix the other moving limb ; this done, the distance both from
first and second station, as also the bases and perpendiculars
thereto will thus readily be seen. Set the perpendicular 2cX
random to any height, move the same till the upper point
intersect the upper limb, or that most distant fiom the base,
then read off on the parallel, the divisions parallel to the base
subtended between the two hjpothenuscs or limbs; if this
distance or division be equal to the distance measured on
the base line, {i. e. 50) then the distance of the object from
both stations will be shown on the two limbs, as will also tl»e
base and perpendicular on the resf>ective lines. If the divi-
sions on the parallel (\o not agree with the distance measured,
the perpendicular mu^t he altered till that division is shown,

when

PLOTTING QUADRANT, LEVEL, AND CALCULATOR. g^J

when the required distance will be given. This is a case of
our first problem.

Fourthly. — To leveU or measure the altitude of any object.

It is only neces«*ary to set the plane of the instrument ver- To measure
tical, instead of horizontal, by means of the joint under the '^^ object. ^
instrument, whence it is evident every case may be known as
on the horizon; and to level, it is onlv requisite to set the
spirit level at the back of the instrument, the base line and
every object cut by the same will be level thereto.

Fifthly. — To take angles or altitudes at sea, where the instru-
ment cannot be made statiof/ari/.

For this purpose, it is first requisite to chanp^e the sight a. To take angles
Mg, 1, and substitute the ond b, Fig. 2; which being firmly or^ltiiudes at
fixed and adjusted at right angles with the upper limb, it is
evident that when by reflection any object is brought to co-
incide on the mirror, at the extremity of the base Hue, with
another object seen in the dire( tion of such base, the angle
will then be known, being double what the uup'^r limb de-
notes on the arch, to which true angle, or ?ts double, the
loiver limb may be fixed, leaving the oc.e with the mirror
again at liberty to take another observation and angl<% a^ any-
distant place, or time; which being ^o taken, thi;s li^nb may
be also moved and fixed to double its appar/ent angle, and
the altitude or distance be then determined, by sctt ?;g the
perpendicular and parallel as in other common caa^ is on land.

From this mode of determining distances, as the use o( cal- Su; '^r^edefthe
culations and of tables of sines and tangents is supeseded, use of calcula-
itis presumed that much convenience will arise to th^ unlet- 1,;^',^ of s .. T
tered who may have occusion to use it, and thereb} the errours ^'^^ t.u geats.
of calculations will be avoided.

As well as the before-mentioned purposes to which the in- '^ arions other
strument appHes, it is presumed there will be i'ouuti oiher """'^ 'o vv^^^hJi
things which it will pes f urn, some it is hoped useuii, and
jBome amusing, amongst which may be enumerated. Multipli-
cation, Division, Rule of Three, Double Kuh of Thee, &c. ;
d'Ctermining the area or s-.des of any sort o^ fia^jgle i\om any
jnoperdata; determining the inscribing or inscribed circle

YuL. XVIU— Nov. 1807. Q of '

^26 PLOTTING QUADEANT, LEVEL, AND CALCULATOR.

of any triangle, square, or polygon, showing a mean propor-
tional between two numbers, &o.

It is presumed, that an instrument, if perfectly made, on
a large scale, would be found very useful and accurate in
various practical calculations, as well for making them, as for
proving them after made in tigures.

The following are specimens of the manner of calculating
by this instrument.

First Question. — Jf £\Q0 in 12 months produce 80 shillijigs
interest, what will ^£'200 produce in 18 months, and also
what will it produce in 12 months?

Question in On the base line of the instrument set ^100. On the

«d by U ^^^ 'perpendicular set 80 for shillings interest. Then bring the
lower limb to intersect, whkh angle will then be, as per
question, equal to 12 months at all places on the base; hav-
ing so fixed the loiver limb, move forward the perpendicular
till it intersects the lower limb at the height 12 on the perpenri
dicular, then mise the perpendicular to 18, and to the extre-
inity thereof fix the upper limb to intersect, which angle will
then be in proportion as 18 to 12 to the loicer limb, being
equal to the different times. The limbs being so fixed, it is
only requisite to move the perpendicular to 200 ©n the base;
and, raising the perpendicular till it intersects the upper limb,
you will have thereon the answer 240 shillings, and at the
same time, at the intersection on the lower limb, l6o, beijig
the interest for 12 months only.

' Question second. — To determine the imcrihed or inscribing

circle of any polygon, the side being given; for exampUi
a hexagon the side ojtvhich is 100 Jeet.

To determine Set one of the limbs to half the angle included in the

the inscribed or • i • i /. i i /• i » i . .i

inscribing cir- »'ec(uired side ot the hexiigon (i. e, 30 degrees), then set the

cleofapoiy- perpendicular to the height of half the side given, being as
per question 60. Then move the perpendicular till the ex-
tiTmity intersects the limb before set, on which, at such inter-
section, will be denoted the radius of the inscribing circle,
and at the same time may be seen on the base the radius of
the inscribed circle.

Question

PLOTTING QUADRANT, LEVEL, AND CALCULATOR. QQJ

Question third. — Tojinda mean proportional as between 6C0

and 200.
This depends on the well known property of a right angled

triangle.
Set the perpendicular on the hase line, at the distance of To find a mean
lialf of the difference of the two numbers [i. e. eoo — «o.o); this P'-oportional.
done, raise the perpendicular, and move either of the lifnbs
till the extremity of the 7)<?r/)e«t/ic?//ar intersects thereon at
half the sum of the numbers, being 400. This done, the
height of the perpendicular will show the proportional re-
quired, being- 347»

Note. — On the plate on which the perpendicular slides
will be found Noniuses for subdividing the divisions on the
base or perpendicular into 10 divisions.

Reference to the Engraving of Mr. Saltnon^s Geometrical
Quadrant and Staff, Plate V.

Tig. I represents the face of the quadrant, on which A is Explanation of
the fixed base line ; B the moveable perpendicular; C the
upper limb ; D the lower limb ; E the arc ; F the nut, which
moves the perpendicular by means of a rack and pinion.

G, a spring to keep the perpendicular steady ; H, a screw
for fixing the joint of the staff; a the eye piece, or sight, with
a small hole in its centre; I, I, T, the sights for direct vision,
consisting of only a small slit in each. When objects are to
be viewed by reflection, as with a Hadley's quadrant ; the
sight a at the centre is taken off, and the sight b with a mir-
ror, shown at Fig. II on rather a larger scale than the for-
mer, must be substituted.

Fig. III. — K is the staff, the mode of applying which to
support the instrument when in use is shown by the same
letters in the other figui-es ; L is the screw, by which the staff
is fixed firmly in the ground.

Fig. IV represents the back of the quadrant; M M are
the screws, by which the upper and lower limbs are fastened
after taking an observation.

O, a spirit level ; H the tightening screw for the joint be-
fore noticed ; P the socl<et attached by its joiiit and tighten-
Q 2 inP

128 DESCRIPTION OF A LARUM FOR A WATCIf.

ing screw to the back of the quadrai'.t; the staff K is screwed
into the above socket.

jF^o*. V shows the pi:actical method of using the instru-
ment for determining the distances of the objects Q end R
from the two stations S and T, at which the instrtiment is to
be successively pkiced, and used as before described.

Fi^, VI is the diagram referred to at page 220.

Fig. VII represents the mode of applying the tightenii)^
screw H, In Fig. I and iV, by means of the seiuicircuiar
spring, enclobjng the cylindrical stem, or neck of tiie joint.

Description of a Larvm appUcahle to any Pocket Watch, hy Mr»
John Prior, oflSessJield, near Skipton, in Craven*,

Ap-licdble (o JL N constructing this machine, I have endeavoured to makfg

w mut niur- ^* ^^ simple as I could ; so that by the assistance of a pocket

iug it, wrtrh, of any size, or any number of turns of the fusee,

which ever way it is wound np, it will cause the larum to let

go at any time required, without hurting the going of the

watch.

New method In winding up the main-spring of this machine, I have

", ^"''.'"^ "^ u?ed a niethod different from that of an v other person, and

I lie "lain- " ^

spring, which adrhits of Its acting with considerably more power than

where thicker pivots are used,
and >topping it The discovery of stonping the main-spring when wound
with.uta ^jp witbrnt a fusee, I must beg leave to say, gives me a

great deal of satisfaction; and will, I hope, be useful to my

brother workmen.

To show with what ease a watch will turn the larum screw,

I made the following exp' -iinent.
Ease with When the machine was wound up and the lever put u|)0i^

which it acts, j^^ screw, I turned the a\is of the screw, while one o^ the

pins, which has a communication with the key when the

** The Society of Arts voted Mr. Prior their silver medal and twer ♦; ^ui-
lU'jii; for thi^ iiiYcntiou. Traus, Vol. XXIII, p. ;39.3.

match

. DESCRIPTION OF A LARUM FOR A WATCH. 22?^

tvatch is put to the larum, was parallel to the horizon ; its
distance from the centre of motion was one eighth and
three fourths of an inch. I hunj^ a slender thread upon the
pin, with ten grains troy weight tied to it^ which moved the
crew.

This larum maybe seta week before-hand, if the watch May be set as
would go as long, by increasing the number of threads of hand as the
the screw. watch will go.

When a watch is made to wind up the contrary way, it is Left hand
necessary only to take out the pin in the axis of the detent, ^^^^ *
and turn the lever the other side up, and then it will drop off
at the other end of the screw to disengage the laru'^.

By taking notice at what hour you wind up your ^'atch, Number of
and by winding it up again at twenty-four hours, you v, ill ^£^i^J^(^^qq^^
ascertain how many hours are contained in one turn of the
fusee, the most common are four, five^ six, hours for each ,
turn. I have divided the common index into 120, which
does for three concentric circles. That next the centre is
for a watch fusee of four hours a turn ; the next five, and the
last six. While the hand of the larum passes over one of the
"jdi visions, it will be equal to two minutes to the four hours
«ircle, two and a half to the five hours, and three minutes to
the si!t hours circle, all shown by the same hand.

Before a v/atch is put to the larum, it must be fitted with A particular
n key that will not drop off when the watch is turned with ^^^ i^ecess^ry.
the key-hole downward, something like that which I have
sent ; then hang up the watch by the pendant to the holder,
which may be turned while the key end on the watch is
opposite to the axis of the screw, and the face of the
watch parallel to the plate. Then turn the sliding pieces
any way, as may suit the watch in that situation, and
screw it fast.

Supposing the watch is four hours in making a turn of the Method of set-
fusee, turn back the hand of the larum while one of the pins ^i"§ ^^«
touches the pin in thew^atch key, and if the han^ is not at
top, turn it back till it is. If the larum is required to go off
4n foui* hours, lift the lever into the first turn of the screw ; if
in fi^e hours, turn back the larum hand one hour; if in six
horn's, two back; if in seven hours, three back ; and if in

eight

2^0 DESCRIPTION OF A lAEUM OF A WATCH.

eight hours, do not turn it back, but put the lever into th*
second turn of the screw ; and so for the rest.

I am, Sir,

Your very humble servant,

JOHN PRIOR.

Reference to the Engraving of Mr, Prior' slL^arunu PL VL
Explanation of pig. \ shows a bird's-eye view of the machine,
t e p ate ^^ shows the position of the watch on the larum.

B. The spiral cylinder, fixed on the axis, and moved by a
pm across a key placed on the fusee square of the watch.

C. The acting lever, one end of which lies upon the spiral,
the other end is movable upon an arbor D.

E, shows a notch cut in the arbor D. This notch is cut
more than half through the arbor, in a situation opposite to a
pin at F, in the middle of the rim of the larum contrate
wheel G. When the lever C falls off the cylindrical spire
B, the notch E is moved to a situation so as to allow the pin
F to pass through the notch which discharges the larum
hammer H, which works by pallets in the contrate wheel G
in the usual manner*

O. The barrel which contains the spring, the inner hand of
which is connected with the same axis as the contrate wheel.

K. The finger piece which winds up the spring.

h, b, b. The three sliding pieces which hold the watch.

e, c. Two projecting pins, which are carried round by the
pin d, which is fixed across the key fitted to the fusee.

Fig, 2 shows that side of the machine on which the watch
is fixed.

a. The sliding piece, on which the pendant of the watch
is hung.

b, b, b, The three sliding pieces which serve to adjust the
watch, and hold it in such a position that the fusee square
maybe in a line with the axis of the spiral cylinder B,
slwwn in Fig. 1.

1 is a ratchet wheel, on the centre of which is a button or
finger-piece K, to wind up the larum spring.

L. The

ON Blasters ajmd soaps, g31

L. The click which works in the teetli of the ratchet wheel.

IJ. The lower part of the arm of the hanimer.

M. The bell, within which the hammer strikes*

N. The cock in which the pivot of the axis of the pallets
acts, and to which the hammer is connected.

Fig. S, shows a section of the ratchet wheel and spring
barrel, which are screwed together, and move at the same
time, bat are kept in their place by two pieces e, e, which fit
a groove in the barrel.

K. The button or finger piece;;

I. The ratchet wheel.

P. The box for the spring;
'R* The cap which covers the spring box;

V. The axis on which the main spring is wound*

Fig, 4. R. The cap, under which is the spring. On th8
edge of this cap, at S, is an indent to retain the spring when
wound up;

T. A lever, with a hook at its end.

At the end of this lever, on a line v/ith the hook, is a small
piece of steel, which goes through a hole in the box, and
presses upon the main spring; so that, when the main
Spring is wound up on the axis V, the hook is at liberty to
fall into the way of the indent S, and is there stopped.

Under the lever T is a small spring, which presses it
against the main spring within the barrel.

Fig. 5} shows the' index of the larum ; the outside circle
of which is divided into 120 parts, which index serves for
three concentric circles; that next the centre is for a watch
fusee of four hours a turn, the next five, and the last six, as
explained in the letter* '

XI.

Ohservatioris on the Comhination of fixed Oils ivlth the Oxides
of Lead, and with Alkalis: by Mr. F. Fremy, Apothecary ^
of Versailles*.

CHEELE was the first who observed, that the water, ^y^^^j. ^^^^ .^^

which serves as an intermedium when fat oils are combined making ti

tkarg'^ plaster
• Annales de Chimie, Vol. LXII, p. 25j April, 1807. is sweet.

with

232 ON PLASTER! AND SOAPS.

with litharge, hold in solution a substance, that he called the

Svreet ptjnci- sweet principle of oils, because it has a very decided saccha-

pco oi b. rinfi taste. But as, acrordins^ to the observations of that

eminent chemist, the water likewise holds in solution a cer-

Is •• not ow-ng tain quantity of oxide of lead, may it not he inferred, that

this taste is owing to the property that metal has of impart-

Que^tions to ins^ sweetness to n;ost of its compounds? If experience

be aiiswcrvid. pjoye the cont'ary, would it not be interesting, to inquire

how tins principle is formed ? what are its properties ? in

what state the oil is left, alter having lost the principles that

give birth to it ? whether this abstraction be indisDensable

to the combination of oil with oxide of lead? and on the

exj>eriments necessary in this research to establish the theory

of one of the most important operations of pharmacy and

the analogy of its results to alkaline soaps ?

Such were the propositions that led to the experiments I
am about to describe.
Oil litharge ^"*^ ^ tubulated glass body I put equal parts of olive oil,

and water litharfre, and water. To its tubulure I adapted a tube, ter-
tUer^ minating in a vessel of lime water ; and to its orifice a blad-

der, to prevent the contact of air. This bladder was so
contrived, as to allow me to stir the matter with a spatula, so
The oxide as to prevent it sticking to the bottom. Having brought the

changed yel- ^jixture to boil, I observed the oxide of lead change in sue-
low, andthen . „ , „ , p ,, ?. 1
white, cession from red to yellow, and irom yellow to white : and

and carbonic during the experiment carbonic acid was almost always fly-
acid evolved, ing off. Having suffered the apparatus to cool, I examined

the results of the experiment in succession.
Tiie water hjad The water, that had served as an intermedium, had a
te'^rl' would strong metallic taste. With the addition of yeast, and at a
not ferment, proper temperature, I could never biing it to ferment*. It
Lead precipi- formed an evident precipitate with sulphuric acid, and with
uted from it. hidroguretted sulphuretsf. I passed sulphuretted bidrogen

through it, till nothing more was thrown down, and then lil»

tered to separate the sulphuret of lead.

• I was for a moment led into an errour, by employing yeast, which,
not having been washed, contiintd some iilcohol.

_,, ,. , + I satisfievi myself by various expcrimeiii^, that it is of no consc-

Oil dissolves ' ■' ' , ; , , r , ,, ■,

t«^d without quence to the solution of oxiJe of lead, thai the oil or fat should be ran.

teing rancid, eid, as Scheele supposed.

The

ON PLASTERS AND SOAPS. Q33

The filtered liquor still retained a strong saccharine taste. The filtered U*
It was evaporated to the consistence of a sirup, and the ace- Evaporate4.
tate of lead then no longer indicated the presence of suU
phurctted hidroL^en. My attempts to ferment it vvefe as Would not fejir
unsuccessful, as before the oxide of lead was separated. *^^'^"'-
Exposed to tb.e air, it strontjly attracted moisture: thrown on Attracted
burning coals^it flamed like an od: on boilingit with the red, burned >vith
j^ellow, and white oxides of lead, it dissolved only the yeU ftame: dissoly^
low: on distilling it repeatedly with nitiic acid, oxalic acid of^ad-*formed
was formed: distilled in a retort on an open fire, part of it oxaiic acid.
rose, as Scheele observed; and by increasing the heat the its products.
products were an empyreumatic oil, acetic acid, carbonic
acid, carburetted hidrogen gas, and a light, spongy coal,
containing ho oxide of lead.

Froiu what I have mentioned it might be presumed, that
the oil, when it had combined with the white oxide of lea^d,
was not in the same state as before the combination. ,

To free it from this oxide I employed acetic acid, because rated^from^the
the solubihty of acetate of lead would affo-d ready means oxide.
of separating it from the oil, the properties of which I wishe4
to examine.

This oil has the cons:stence of soft fat, and the taste of ^^^ characters,
this animal substance when rancid. It is insoluble in water,
but soluble in alcohol ; from which it is precipitatfivd by water
as volatile oils are, and like them partly rises in dijitiilation*.

The slightest boiling is sufficient to combine it perfectly Readily unites
with white oxide of lead, and give it the consistence of a )'^^^^ y,'"^'^^ <^^-
fttrong plaster, which does not take place with litharge, or
with massicot.

The yellow and white oxides of lead cannot comlane with Neither white

common oils. I satisfied myself of this fact by boiimp-them ."°/y-'^^w °^-

-^ -' "> '^ ide unites witt^

t<)g€ther much longer, than would have been necessa'-y if I common oil.

had used litharge.

From these experiments it follows, that, when fat oils are Oxigen of li-

treated with litharge, the oxigen of the latter takes from ^^^^'S^ takes

them carbon, and previously hidrogen, to form with them dro^^en from

water aud carbonic acid. oils,

♦ All fat oils are soluble in alcohol j but they are far from possesiJiig ^

this property in so striking a manner, as after they have been boiled with
litharge.

' That

234 ^^ i*LASTERS AND SOAPS.

and thus pro- That this abstraction, rendering the oxigen more abim-
priudokr'^''^* dant in the oil, j^ives birth to that saccharine substance,

which Scheele calls the sweet volatile principle ol' oiLs.

BifFers from That this sweety principle differs from the raucoso-saccha-

mucilage and ^.-jp^ ]^^ -^g property of dissolving the yellow oxide of lead :

that its presence is independant of the presence of oxide;

and that it differs f-om sugar by its volatility, and by the

impossibility of brii.ging it to ferm nti

The oil ac- That the oil, deprived of the elements that give birth to

proptrUes"of *^^^^ sweet principle, and the quantity of hidrogen and car-

irolutile oils, bon that constituted it hxed oil, acquires several of the pro*

perties of volatile oh
The only state And finally, that this last state of oil is the only one, in
combines with ^^^^'^^ '^ ^^^ combine with white oxide of lead.
lead. From the knowledge 1 had' thus acquired of the theory of

Are plasters this combination of oils, I thought I ishould not neglect to
la ic soaps, examine how far the opiaion of several chemists, who con-
sidei' plasters as real metallic soaps, is well founded. The
analogy between plasters an<l soaps can be confirmed only
by observing in their respective combination's a similarity of
phenomena, or at least of results.
Strong lie -. I mixed very pure soapboilers lie with olive oil, a«d ex*
mixed with posed the mi?fture to the air under a glass jar. A week af-
ter there was but a very slight absorption ; the sOap had still a
strong alkaline taste ; and the oil of tl;is soap did not dis-
solve entirely in alcohol. But at the end of six weeks the
absorption of oxigen was complete; the soap was very white,
and of a good consistence; the taste of alkali in it was
faintly perceptible; dilute sulphuric acid extricated from it
carbonic acid ; and the oil proceeding from this decomposi-
tion had the same consistence as that from plasters, dissolved
very readily in alcohol without the assistance of heat, and
was precipitated from it by water.
Uo sweet prin- ^ made some soap in the same way as soapboilers, and very
eiple in water attentively examined the liquor, that remained after the soap
soa^p.™^ "^ ^'^^ completely formed; but I could not discover in it any

trace of the sweet principle.
The efF^ct dif- -^^ *^^ absence of this principle in making an alkaline
ferent-in de- soap probably depends only on a greater or less abstraction
San'iiTkind ^^ Carbon or of hidrogen ; and in other respects thi; action

of

I*RETENDED NATIVE MAGNESIA. ^^5

of dxigen on the oil, and the state of the oil, are absolutely
the same in the fabrication of plasters and of soaps ; T con-
ceive, that plasters Ought to be considered with respect to
soaps the same as insoluble metallic salts are to alkaline salts.

I satisfied myself, that the want of consistency in soaps Soaps with
made with potash is not at all owing to the state of the oil, ^rom t*hena-
but to the nature of the compound; for by treating with tureof theal-
potash the oil obtained from a very hard soap of soda, I ^^^'*
could form nothing but a soft soap*

XII.

Account of a pretended pure native Magnesia*.

HE German dealers in minerals sell under the name of Fossil sold as
pure indurated magnesia,, and as coming from Moravia, a ^"theGerinan
mineral substance found in amorphous masses of the size of dealers.
the fist, covered with an earthy crust of a yellowish white
colour, that slightly adheres to the tongue, and is a little
gteasy to the touch. Its fracture is dull, entirely compact. Its characters.
imperfectly conchoidal, and approaching to a plane : its co-
lour is yellowish white: it has small cavities, lined with lit*
tie mamillary projections, that appear to be composed of
crystalline points when viewed in a strong light: it is suffi*
ciently hard to scratch glass, and steel leaves a coloured
mark on it, but it does not strike fire with steel : its specific
gravity is 2*83: at its edges it is very transparent: it does
not absorb water, or adhere to the tongue.

Before the blowpipe it cracks, and does not melt : it is not
at all phosphorescent: it dissolves with effervescence in the
nitric and muriatic acids; with the sulphuric it occasions a
copious precipitate*

It cannot be confounded with the native magnesia of Difference of
Werner, which is easily scratched by steel, strongly adheres native magnet
to the tongue, and is of the specific gravity of 2 '88. ^^^'

This mineral, analysed by Mr. Bucholz, yielded in 100 j. ^onent

* Journal des Mines, January, 1807, p. 7o.

parts

§B6 , REMARKABLE OCCURIIETCCES IN NATURAL HISTORY.

pirU. parts 23 of pure lime, 20*5 of pure rruiJ-nesia, 1'5 of man*

ganese with a little iron, and 48 of carbonic acid.

A jfiiu-ituUite. Hence it appears, that it is a ran'ricalcite, or a varictV-of
the bitterspath of the Germans.

XTII.

Some rcmcrliuhle Occurrences in Natural Ilistori/, From the
Rev. James IJairs Traoeh in Scotland.

MILE Mr, Hall was at Elchies, on the north-west banks
of the Spey, abont fifteen miles from Elgin, he saw a remark-
a!)ie migration of eel-. The following are his own words.
i^figiv.tiua of A\hen I first observed thetn, it was about one in the af-
*'''^'' ternoon of a Sunday. How long the eels had been trans-

migrating before I know not. They continued making their
way up the river all that day till about eight iri the evening,
when it grew dark. They began again early next morning,
biit how long before five I cannot say. They continued to
fnigrate for three whole days after I observed them, with
6nly an interval of a few t»oars in the night. They kept as
iaear the north-west edge of the river as they could: an«i,
when there wer^ bays in the edge of it, they went regularlv
V, t-A^oV -.o , roiiiid these, whether great or small. They were about i:en
at rogdUr dis- abreast, and each eel about three inches and half long: they
aaces. niarched tit regular distances, wliich might be about four

feet; or rather three feet and half. There were stronger
eels as a guard, and geiierally about five or six inches long.
s-KilUst v.kxt ^ obscrrv^ed the smallest and weakest ones always kept nearest
the ihoro. the ed^e, where the current was least. From an accurate
calcuialion a hundred passed every minute, making six thou-
sand per hour. <

They proceeded at this rate for three days, from about
. half an hour beiore the sun rose till about half after he set,
to u iituc after njHkirig about sixteen hours each day, in all about forty-
eijjht hours, which, multiplied by the six thousand that
passed every liour,^ make two hundred and eight\^-eight
thousand, most of which I saw pass; but whence they came,
or what they were in quest of, 1 know not. They did not
stay for one another, but each made the b^st of its way,

wriggling

REMARKABLE OCCURRENCES IN NATURAL HISTORT. ^Sf

wrij^trlinjy with tli€ utmost celerity ; and wheu I pushed any
of them farther into the river, they always came to the edge
as fast as they could. Not one but had its head up the wa-
ter. Tltey seemed to be in great haste, and breathing hard, Travelled hasr
as small bubbles of air often rose up to the surface ; and *^ ^*
when, having caught any of them, I turned its head down-
warfl, so as to swim with the current, it would not, but with
all the expedition in its power joined its new companions,
and wriggled on along with them. As I could not be always All at once Hi4
there, I appointed others to watch their motions, and I |[je'"j|^^':j^"^.^'^
found, though I could not see exactly how they acted, that, yards j^ijglit^
during the time it was'beginning to grow dark, by a kind
of signal, they all at once hid themselves in the sand or mud

for miles at the same instant, and seemed not only under .

^ ' Apparently
the command, but the protection of the larger ones, that, under the conj-
like officers, commanded them. Indeed, I saw sometimes ^"'"^ of largejr
large eels from twelve to fifteen inches long, making up the
water now and then, about three or four j^ards farther to-
wards the middle of the river, and about five and tvienty
yards behind one another; but whether they v^ere connected
with the general emigration I know not, though I rather
suppose they were, as they were never above twelve or thirr
teen feet from the small eels, and often seemed to turn an
anxious look towards their young friends. Tlie young ones,
as they were near the edge, were seldom an inch below the
surface. Those about five or six inches long might be bcr
tween one and two inches below the surface, being in deeper
water, and the large eels went at a much greater velocity
than the small ones. But, if thfv had any connection, or
care of the small fry, they must sometimes have stop-?
ped short, or slackened their f)ace. 1 luive seen the horse
and foot guards reviewed by his majesty in Hyde Pavlv,
and ten thoui^and men performing the same action at the
same instant of time; but the eels in the river Spey kept *
their ranks as regularly, and seuined to be as subservient to
the gi'cater ones, as any of the corps at a review are to the
command of their officers.

Another fact he observed n\ay be mentioned as an instance
of the resources of animals, when prevented by circumstances
fiom following the usual practices of their species.

Nece;^sity .

235 REMARKABLE OrCURRENCES IN NATURAL HISTORY.

Magpie's nest Necessity often leads both men and other animals to do

bush. what they otherwise would not. As I was one day amusing

myself with the objects around me, on the road between

Huntley and Portsoy, I observed two mas^ples hopping round

a gooseberry bush in a small garden, near a poor-like house,

in a peculiar manner, and flying out and in to the bush. I

stepped aside to see what they were doing, and found, from

the poor man and his wife, that, as there are no trees all

around for some miles, these magpies, for several years,

built their nest, and brought forth their young in this bush.

Strongly barri- And, that foxes, cats, hawks, _&c. might not interrupt them,

e*do€d. ^i^^y j^.^^ barricadoed, not only their nest, but the bush all

around, with briars and thorns, in a formidable manner ;

nay, so much so, that it would cost even a fox, cunning as

he is, some days labour to get into the nest. The materials

in the inside of the nest were soft, warm, and comfortable to

the touch, but, all around on the outride, so rougli, strong,

and firmly entwined with the bush, that, without a hedge

knife, hatch bill, or something of the kind, even a man

could not, without much pain and trouble, get at their

young; for, from the out to the inside of the nest, it was

longer than my arm. Frogs, mice, worms, or any thing

Assisted by the IJvinj^, was what they brought their young. One day, one
young m kill- „ , .,.*■,• i t i . • i ,

inga rat. of the magpies havmg lighted on a rat, but not bemg able

to kill it, one of the young ones came out of the nest to its
mother and the rat, while they were lighting about the bush,
and assisted in killing it; which they did not accomphsh,
till the father, arriving with a dead mousey also lent his
aid. The poor woman told me, that, of the two magpies,
A chicken res- the mother was the most active and thievish. She was also
cued by its mo- unjcratef'ul . for, although the children about the house

had often frightened cats, hawks, &c. from the nest, yet
she one day Sf^ized a chicken, and earned it to the top of
, the house to eut it. But the chicken's mother flew up after

the magpie, and, having rescued the chicken, took it in her
nib ; and, as it was not able to fly, bi^ught it down in the
/ same way as a cat carries her kittens in her mouth, taking
its neck in her nib ; and the poor chicken, though it made
a great noise while the n»agpie was carrying it up, was ex-
tremely quiet, and teemed to feel no pain while its mother

CHAJICOAL OF MAIZE, ^3§

was bringing it down. These magpies had hevn faithful to Th»»same mag-
one another for several summers, and drove off their young, ft' f^,/ several*^
as well as every one else that attempted to take possession year^j.
of their nest. This they carefully repaired, and barrica-
doed in the spring with rough, strong, prickly sticks, that
they sonnetimes brought to it jointly, one at each end,
pulling it along, when they were not able to lift it from the
g-rouad.

He adds : The same poor people, having one year lost Cbicken nA3Ti>
the niotiicr of some chickens, the cock became their pro- ^ ^ ^^
tector, took them under his wings in the night time, and
whenever it was cold ; and continued this paternal care, not-
^vithstandiug that his wives often tried to seduce him from
the chickens, to attend to themselves. Here too I was in- ^nd young pi-
fornied, a pigeon took care and fed the young himself; his |^^|^* yt e
wife, the mother of the young ones, having been seized and
carried off by an insidious cat.

XIV.

Facts respecting Indian Corn, hy Professor PRouyT*.

A

Hundred parts of the grains of maize, subjected to dis- Charred maize

tilIation,left twenty four of charcoal. I converted into charcoal <^^'''^^'*i"s Pj^os-
1 1 * 7 -11 • -rur 1 , . pnoric acid,

as much as wiren very dry weigned 3^100 grains. Washed m
distilled water, this afforded indications of phosphoric acid ; it
rendered lime water turbid, and precipitated nitrate of lead.

This charcoal was very difficult of incineration. Its ashes, Ver}^ difficult
to obtain which I was obliged to repeat its combustion five ^^ ^"^■^'^^'^'^^^•
different times, weighed only 6o grains. They'^ were carbon^
aceous, f^itty, and without any particular taste. W'^ater ex-
tracted from them but two grains.

Ten drachms of charcoal of maize, after being calcined Ten drachms

for two hours, were reduced to seven. There was no an- ^^ repealed

f. 1 rr.1 11 1 • . n calcination r©-

pearance or ashes. 1 nese seven drachms, ca'cuied tor two duc«4

hours and half, were reduced to sontewhat less than five,

without any uhhes appearing. On calcining them three

hours longer, they were reduced to two drachms thirty

^ Journal dc Physique, Vol I.-XIII, p. 4^i9, Dec. 1806.

240 CHARCOAL OF MAIZE.

^iins. The residuum was still very black, pasty, and ad-

^ hered to the iron with which it was stirred. On washing it

was reduced to two drachms 8 of rains.

toatoutone. These two drachms 3 grains were calcined another hour,

which reduced the weight to about 6o grains ; and were theu

Gave ISgrs.of lij^.jviat^^]^ The lixiviums mixed t^opetheryielded ISi^rainsofa
saline extract. ,. , • ^ i • i .,.,...

salnie extract, the taste or which was not perceptjnly alkalme.

Phosphate of These IS grains, redissolved and drie^l, would not crystul-
potasi. ij^^^ and were reduced to 14. Suspecting that tlie potash

was saturated with phosphonc acid, I dissolved it in distilled
vinegar, and afterward treated it with alcohol. This opera?*
lion reduced it to 11 grains of that acidulous phosphate,
whici. crystallizes in letraedral pnsms termin;ited by similar
pyramids. I foget whether the faces of the pyramids anr
EwCiCd to the faces or edges of the prisn>*

If 10 drachms of chavcou!, the produce of 41 of maize,

gave 14 grains of phosphate, 100 drachms of maize v.ould

J'icld but 34 or 35 gtaiiis, which is far from 40 per cent, as

itienticned in Dpiamctherie's Journal. So great a ditference

could not have escaped such a man as de Saussure: it^ must

have been nn errournf the press therefore, or of the manuscript.

The obstinacy with which the cliarcoal of maize resistsbiirn-

in^ is astonisinnj;: animai charcoal could not exhibit more.

Charcoal frprh i he same plaint affords a ciiarcoal of very different kind.

th^ sMlk bums The charcoal of the stalk, triturated with five sixths its

the time. weight of saltpetre, is consumed in a tube of a given diameter

in '28 seconds, /Vs milar mixture made with the charcoal of

the grains rev^u-ret, 52 seconds for its being consumed in the

same tube*

To Correspondents*

The comiriiracat'on with winch N. R. D. promises to fa--
vour me will be Very acceptable. I have likewise to thank
him for his concluding hint, and shall certainly avail myself
of the sour( e it points out.

Mr. Cayley*s communication is received, but on account
of the engraving it could not be inserted in the present
month.

I hope to be able to give some correct Observations and
Resalts in oar next respecting the Comet, which is at pre-
Wiut visible.

2fuholscivfrhilc<s Journal Volimi.pU^/j. ^^'

Structure of covered/ ways.

^^^ i.n.i, n-.i

Fig.h

ri^.2.

^pczzzz.

Tig. 6.

r — r

7'/y

' .' I ' 1 ' l' .' .^

Pri , r^

, T-_ I ^ I, C

1 I

Fig. 6.

^7-

S=P-

^^'-

I ,t ll, I,

r Tzn:

^ ^^^^

^?s-

^^

I ,1 , ! L

^^'^^ ^^^

Fig. 10.

Fig.R.

Fiq.12.

Fig.m.

""""^^^^^/jy-

"\

«</.?(?.

n

■^^

Fig. 21.

W
w

A

J O U R N, A ]L

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

DECEMBER, I807.

ARTICLE I.

Remarks on the Struchire of covered Ways, independent of
the Principle of the Arch in Equilibrium , and on the best
Forms for Arches in Buildings. From a .Correspondent
(Apsophus).

To Mr. NICHOLSOK.
SIR,

HE subterraneous passages or tunnels of the Babylo- Ancient sub-
nians, and perhaps the cloacae of the Romans, were <^o*^" arch'^^^^'^* ^
structed, according to the opinion of the best informed
antiquaries, by simply causing the bricks or stones of each

, of the side walls to project more and more as they rose
higher, till they finally met in the summit. The most an-
cient remains of the Grecian buildings, for example, the

^treasury of Atreus at Mycetiae, and other ruins in the Pe-
loponnesus, ^exhibit in general over their doors, according to
the reports of modern travellers, a triangular aperture,
formed by large stones ; the base of the triangle coinciding
with the lintel of the door ; and the pointed arches of the

, Gothic buildings aVe by no means universally so ar, .nged,
as to derive their stability from the proportion of therf cur-
vature in every part, to the pressure which would be pro-
duced, according to the commonly received theory, by the
Vol. X VIII— Dec. I8O7. R height

242 ^N THE STRUCTURE OF COVERED WAYS.

height of the superincumbent wall. As far as I know, thi*
subject has not been matheiiiatically investi^ted in all its
parts, and I shatl therefore submit to the consideration of
your readers some propositions relating to the stability of
overhanging walls and of triangular covered ways.
Bricks over- I shiill examine those cases only, in which the materials

hanging till employed are equal rectangular parallelopipeds, whether
thev meet in a ^ -^ ^ , . , t

point. bricks or wrought stones, and m the first place I shall sup-

pose them destitute of all friction or adiiesion, and placed
horizontally. With such materials, it may be shown from
the principles of the lever only, that a covered way may
easily be made, not exceeding in breadth the length of three
or four bricks or stones, and that the combinations, repre-
sented in PI. VII, fig. 1 • •?, will stand in equilibrium without
external support: and that if the breadth of the way be
equal only to the length of two bricks, it may have any
height of wall added over it without destroying the equili-
^o support brium (Fig. 8). These combinations are however incapa-
thewidThmust ^^^ ^^ resisting the pressure of any considerable force, and
be small. the method of building in this manner cannot be generally-

advisable; but the weight of two* bricks is supported at the
vertex in Fig. 9, and by extending the basis, and heighten-
A stronger Jng the wall at the sides, a much greater strength might be
"*• obtained. It is however obvious, that a wall terminated in

this manner would by no means necessarily exert such a
pressure on any stones, forming a facing of the oblique sur-
face, as is commonly supposed in the theory of the arch; on
Arch turned the contrary it is plain, that an arch might be turned under
under it. j^^ which would be sufficiently strong for every purpose, if

capable of supporting little more than its own weight : and
the same reasoning is applicable to the wall in contact with
Pointed arch, the lower parts of every common arch. Hence it becomes
often eligible to construct the arch in such a manner as to
be more capable of resisting a pressure near its vertex ; and
thus its foriti will approach in some degree to that of a
Arches of a pointed arch. The arches of bridges, on the contrary, have
bridge. ^^ support the pressure of materials, of a very different de-

scription ; and for this reason their greatest curvature should
. be near the abutments.

« , s ♦ In the next place I shall inquire into the conditions requi-
R.c<JuwuC8 to *

I

ON THE STRUCTURE OF COVERED WAYS. £43.

site for the stability of an oblique facipg,, composed of rect- the stability of
angular bricks or stones only, both with and without the ^^^^
consideration of the effects of friction. The simplest case
that can be proposed is that of two bricks meeting each
other, and standing on a perfectly smooth and horizontal
plane, the centre of gravity of each' being vertically above
the lowest angle (Fig. 10). But if the base be widened,
the surfaces supporting the bricks must be rendered oblique.
The weight of the brick acts on a lever of vvliich the length
is A B (Fig. 11), in turning it round the point B; and this
is resisted by the horizontal thrust at C acting on the lever
B D, hence the horizontal thrust must be to the v^eight as
A B to B D, and making BE— A B, the horizontal thrust
at B combined with the \veiglit will act in the direction
D E, and the brick Will be supported by a surface B F per-
pendicular to D E. Supposing the thickness of the brick
inconsiderable, the centre of gravity bein^g in the line B C,
taking B G half B H, the line C G will be perpendicular
to the surface on which it will rest in equilibrium ; and this The same prin-
theorem may be of considerable use in carpentry, for find- ojetotheabut*
ing tlie best possible direction for the abutment of a rafter, mentof a raf-
If the abutment is in the direction of the end of t]ie4>lock
Fig. 12, describe on half the diagonal, A B, the semicircle
B C D A; and C B, or D B, v/ill show the position of a
line, which being made horizontal, the block will be sup-
ported in equilibrium. If the horizontal line cross the cir-
cle between C and D the end B will slide downwards, but
if between A and J>, or B and C, it would be urged up-
wards, but the bearing will be transferred to the lower cor-
ner, and the whole will remain at rest: and this will be the
case in all positions, when the circle falls wholly within the
side of the block, that is, when its thickness is not much
less than half its length. Thus two common bricks would Bricks in an
remain firm in all elevations if placed with the narrow sides ^|;^clined posi-
of their ends lowermost; even without any friction: but the narrow sid#
with the wider sides lowermost, they would slide down the '*^°^"^*'^'^'
abutments if the distance of their ends were more than about
twO; and less than fourteen inches.

The last additional circumstance which requires to be ex- Effects of frio
amlned, with regard to the stability of bricks or stones in *^^^*
R 2 oblique

244" OW THE STRUCTURE OF COVERED WAYS,

t'f ,<'>.0':ivv'j ,,',iiyih\\^ :■■■ -i"^.''; • . iii'.i .i,'-. "tJifl 'J/jl.Si'

oblique aitiiations, is the effect of friction or adliesion. Tnis
force may be corL5i(^eied, ii) all practical .inyefefigaiions, as
proportional to tlie mutual pressure of the surfaces concern-
Convenient ed; arid the mo^t convenient way of estimatirisr its mai^ni-
niode of mea- I -^ .. : . .. ,: . .^ ; ., v i ' ' 'i

suring it. tude is to incline the surbices to the horizon, until they begin

to sl'd^ on each other. The angle at which this happens
will be always very nearly il* pot exactly the same for sur-
fages of the same kind, and it may with propriety be called
Angle of re- the angle of repose : and it is obvious, that any other force
poic. acting on the surface in the same angle as that in which the

^orce of gravity acts in this inst;ance, will be completely ob-
yiated by the resistance of the surface : and the friction will
be to the pressure as the tangent of the angle of repose to
the radius. If therefore the surface A B (Fig. 13) is cal-
culated to resist the presswe of the block A without frictioti,
by making the angles B A C and BAD each equal to the
angle of repose, we may determine the greatest and least
inclination which will be sufficient for retaining the block
by the assistance of the friction or .idhesion ; the stability
being greatest of all in the original situation A B. In the
same manner the rectangular block A B, (Fig. 14) will «be
supported by its abutment a$ long as the horizontal line B C
crosses the semicircle within the line AD, DAE being
equal to the angle of repose.
Caseofafacing When two blocks of equal dimensions form an overhang-
on elchsidV *"o facing on each side of a triangular aperture, (Fig. 15)
the upper one is in the same predicament as if it rested sim-
ply on a fixed abutment; the lower oUe is retained in its
^situation by the force of friction only. If ABC be the
^aiigle of repose, the direction of the force supporting each
of the upper blocks will be B C ; and if the vertical line
B D represent tlie weight of the block A, B C will be the
resisting force, and AC the friction, which Counteracts the
tendency of the block B to descend along the abutment.
Worst possible and this force is represented by E B'. In order therefore to
position. flj^^ the postion in which the block B will most readily slide

away, we must make the proportion of E B to AC a max-
imum ; and this will happen, when the mean of ^le angles
T> B A and D B C is equal to half a right angle. For the

f: ilsd

ON THE STRUCTURE OF COVERED WAY3. "1545

sine of the angle DB C being ?-£ and its cosine |^, and

tlie sine and cosine of A B C "being —, and ^, the ^y^e

of DBA is E2_i£i^ + ££A£,'and cpnsequ^nily^ ETlfe

=: BD . D<^-A.B-t-gD A;C^ ^^1^;^,^^ divided by A C, is
B C q

r> n T^ C . A B 5-2Ji, and this must be a maximnm, con-

AC.BCq^ B U q

sequently, B C bemj^ supposed constant, —- . • ■■ 4-- ,, ;^

must also be a maximum. Then if we make D F perpen-
dicular to B C, and the angle F D G =i A C B, D F will

be 5^, F G = :^. ^££, and B F ^ i^, so that B G "X

B C AC BC ^>^ '

must be a maximum, which will evidently happen wh^ti
DG is a tangent to the semicircle BD G, and the angle
D B C half D II C, which is the difference between ABC
and a right a-rigle. If we wish to determine tlie ^oj>ortit)n Case of the

of the friction to the pressure when tlie friction is barely ^J^^^f^ ^^^^

*■ ..... bureiv sum-

capable of retaining the block in its situation in the most ci nt to retain

unfavourable position, let x be the sine, and y the cosine 6f ^'^'^ ^^ock.
hAlf the angle A B C, then the sine and cosine of half a
right angle being -v/ J-, the sine of A B D or BD E, as
well as that of B CD, will be a/ | ;r + 1/ f «/. Now, if
the weight be B D, B C zz !iiL_, and the sine of ABC

being 2xt/, A C is "^^^ but the weight which pro-

duces the friction is three times the weight of a single block,
the friction on the upper surface being derived from the
pressure of the highest block, and that on the l«wer frOm
the pressure of both blocks; while the tendency to descend
belongs to the lower block only, and is therefore expressed
by B D. -y/ 1^ [x + y) ; hence we have the equation V, |

(.1- + 1/) - -7 r/-^V-^ ' tlierefore i {x + i,'] ^ - G x y,
V 2 V'^ -r y)

[x 4- y)2 — I'i xy, x^ 4- y^ = lO'J^y ==: Ij 2a:y — i, which

is the sine of A B C, and the friction is in this case to .the

oblique resistance as 1 to 5, and to the pressure nearly as The frictioh

10 to 47 : so that whenever the friction is ereater than this, sufficient to re-

II taui two pairs
which

^246 ON THE STRUCTURE OF COVERED WATS.

of blocks in which is almost always the case with the materials common-

poi,i ions, j^, employed, two pairs of equal blocks meeting each other

in this manner will be secure from sliding in every possible

When more, position. If there are mqre than two blocks on each side,

or if the lower blocks are larger than the upper one, the

force tending tp support thp lower ones, which is deriv«p<l

from the pressure of the upper one, is twice the impiediate

friction occasioned by its weight, since the same pressure

acts in two different places, and as long as this exceeds the

difference between the friction and the relative weight of the

lower block or blocks, they will be secure from sliding along

Friction of ^|jg abutments. For example, in the case of comrrion bricks

common bricks "' " . . .

half the pres- pr stone, the friftion is at least half of the pressure ; for if

sure. a brick he placed with the short side of its end downwards

on another which is gi:adui|lly raisecj, it will full over before
it slides; we may therefore safely estimate the friction as
equal to half tlie pressure, the tangent of the angle ABC
heing '5, its sine •446, and its cosine '892. Now if the
18 bricks miglit whole aperture be supposed equilateral, the sine of 1) B A
cleof 60^"^" will be *5, and its cosine '866; and the sine of D B C near-
ly '06', and the friction A C will be to the weight B D ^s
•45 to 1, and to E B as () to IQ, so that 18 bricks on each
side might be secured from sliding by .the double effect pf
the upper pair.
Two modes in There are however two other ways in which such a struc-
which >!i y ture might give way: the lower portion revolving on its
w*y, lowest point, and the higher either moving with it towards

the opposite side, or sliding upwards in a contrary direction:
and in order that the pile may stand, it is obvious that it
must possess sufficient stability in both these respects.
When there aie only two equal blocks on each side, it is
• easy to determine whether or no their breadth is sufficient to
prevent their both falling inwards, by^describing round the
triangle ABC (Fig. 10), a segment of a circle, making
D E vertical, and joining A E, which mu?>t either coincide
with the diagonal A F, or be below it. If there are more
^han two pieces on each side, in order to determine the sta-
bility of any joint A B (Fig. 17), let A C and D E be ho-
rizontal, and F E vertical, draw D B C^ make E H zn E G,
and II 1 horizontal and equal to half A C ; tlien if F I fall

belovv

ON THE STRUCTURE OF COVERED WAYS. £47"

below B, tlie structure will not i^ive way at the joint A B.
The demonstration may easily be deduced from the princi- Two modes ia
pie of the equality of the horizontal thrusts in the case of'^'^^'^^^^^^y
- an equilibrium : and it may be shown, that, if the aperture way.
be equilateral, 15 common .bricks on each side will stand,
but 16 will give way at the sixth joint from the summit.
The stability is howeyer less considerable with respect to the
second mode of failure, in which the upper brick slides out-
wards, while all below it fall inwards (Fi^.18). In this
case the angular motion of the two portions is initially equal,
the points A and B remaining fixed. The velocities of the
centres of gravity reduced to a vertical direction are as the
distances C D, D E; in order therefore that there may be
an equilibrium without friction, the weight of the upper
portion must be to that of the lower as D E to C D ; and
in all cases the force of A D, tending to support D F, is to
the weight of D F, acting at its centre of gravity, as

A G , C D to F G . D E, or as A G . ^ to F G. The

friction of the upper block, of \vhich the magnitude may

be determined in the manner already shovyn, will act upon

the Vvhoje length of the arm F G, while the weight of D F

acts only on the length of half I) E, consequently its effect

ijiustbe considered as increased in the ratio of D E to twice

F G. Thus if we take the example of an equilateral aper- 7 bricks would

ture, constructed wjth 8 common bricks on each side, and ^^^"'^ ^y ^^^'''

. , ■ ,. T • 1 /-( TTx Ml 1 ^ • 1 -•-.. T-. o^Vn weight t 9

without cement ot any kind, C U will be 9*3 inches, U E would not,

2*7, and F G 21 ; hence the brick A will produce imme-
diately a force equivalei^t to the weight of 3*4 bricks, and
by its friction, which is ^% of its weight, another force equi-
valent to the weight of 7 more ; consequently the sum of
both will be fully adequate to the support of the 7 bricks
which form the lower portion of ttje structure. But if we
mulve the same calculation for 0 bricks, we shall find that
they will not stand without sdme external support.

It is pbyious that in all these cases the addition of any This compared
bad at the e^ummit of the structure would very materially ^'*^ ^^^ *^*^^*
increase its stability, and that even a block, of sufficient
magnitude to till up the angle only, would enable us cotisi-
4er:ibly to extend the base. It is also plain, that an inclined

facing"

2'48 ' O^ THE STRUCTURE OF COVERED WAYS.

facing of this kind is not distinguished from an arch by the
want of a key stone, since the two middle blocks act nearly
in the same manner ai if tliey were united, except when they
are forced outwards by the pressure of the lower parts ; and
a centre is as necessary for rasing a facing of this kind, as if
it were an arch of any other form.

I am, Sir,

Your very obedient servant,
17 Oct, 1807. APSOPHUS.

Postscripts — The equilibrium of the flattened arches,
commonly placed over windows, may be determined in a si-
milar manner, the princi|Sles being the same as those which
are employed in the construction of Fig. 11 and Fig. 13.
Supposing the blocks without friction and of equal height,
if their di/isions converge to one point, the lateral thrust
will be equal throughout, and the whole will remain in equi-
librium,, provided that the ends do not slide outwards. In
order to find the breadth which i^ within this limit, let the
horizontal line A B (Fig. 19) pass through the centre of gra-
vity of the blocks, draw any line C B from the centre of
divergence C, make B D — A B, join C D, and let the
vertical line B E meet it in E; then E F, drawn to the in-
tersection of the semicircle E F G with the lower termina-
tion of the blocks, will show the direction of the abutment
d, which will afford an equilibrium : and C H parallel to it
will determine the greatest breadth that will stand. But
since the blocks thus disposed, and supporting a wall, can-
not slide away without displacing the superincumbent
weight, the whole wall may be considered as adding to the
height of the blocks, and the stability in every case that
can occur in practice, must be completer it is oiily neces-
sary to reduce the horizontal thrust as much as possible, and
this must be done by making the point C as near the blocks
as convenient : the thrust being equal to the weight of the
portion A H, supposing A C H half a right angle. If we
wish to estimate also the eiiects of friction, let the segment
E I G contain a right angle diminished by the angle of re-
pose, then C K, parallel to E I, will be the direction of the

abutment

ON THE STRUCTURE OP COVERED WAYS, QJj^Q

abutment wbicb will secure tbe blocks, from sbdlng out-
wards, wltb tbe usbirftance of tbe force of friction. Gene-
rally however tbe obbquity must be mucb less tban tbis ;
and tbe resistance of tbe abutment becomes capable of be-
inu: exerted in the most tavouruble direction that its friction
will allow, that is, in a direction more nearly Vertical than
tbe perpendicular to its surface, for example L M, M L N
being the an^le of repose; and if we wish to have tbe thrust
equal throughout, we must employ blocks of such a form
that their divisions may make, with tbe lines converging to
C, angles equal to M L N; this however would lead us to
make the middle blocks of the form of inverted wedges
(Fig. 20), or at k-ast to make their divisions pdrallel : but it
will be sufficient in practice to cause the parts next tbe
abutments to converge to points somewhat nearer than the
point of convergence of tbe middle parts (Fig. 21); nor,
indeed, has this arrangement any material advantage over
the simpler form of lines converging to a single centre.

From a consideration of these principles, we may derive Observatiota
some useful inferences with respect to arches in g-eneral, ^'^ ^' , '^^ ^"
especially such as are employed in buildings.- The objects
to be attained in the construction of an arch are to diminish
as much as possible the horizontal thrust, and to secure the
stability by such an arrangement as requires the least size
in the blocks and firmness in the joints. The size of the Size of the
blocks must be such, that the curve of equilibrium, under ^^^^^^'
the pressure actually produced by the walls, may be every
where included within their substance, and even without
coming very near their termination ; and the horizontal „ - . ,
thrust will be less in proportion as the curvature at the ver- thrust.
tex is greater, that is, other things being equal, as the arch
is higher. Supposing the height of the wall supported by
tbe arch to be very considerable in proportion to that of the
arch itself, the curve of equilibrium must be very nearly a Curvature.
parabola : if the wall is raised but little above the arch, it
will approach to a segment of a circle. In order therefore
to find whether the size of the blocks is sufficient, describe
a parabola through the summit and the abutments ; and if
it pass wholly within I'he-blocks, they will stand ; provided
hovv ever that their joints are either perpendicular to the

CUA'C,

550 " CAPILLARY ACTION.

curve, or are within the limits of the angle of repose on eirr
ther side of the perpendicular. But if the wall is very low,
and the arch flat, a segment of a circlp will be more cor-
rect than a parabola. Hence it is obvious, first, that a seij;-
Circle prefera- ment of a circle is a better form for an arch than an ellipsis
lip^sis° " ^^ P^iual heij^ht and span, although less pleasing to the e^e^

the horizontal thrust being less: secondly, that for the same
Pointed arch reason, a Gothic or pointed arch is preferable to a Saxon or
rases"^ '^^^^^^^ semicircular arch, when its heiglit is greater; and even when
the height is equal, an arch composed of two panibolic seg-
ments meeting in the vertex is stronger than a semicircular
arch : for, supposing the whU very high, the depth of the
arch stones of a semicircular a^ch must be at least yV of
the span, in order that the arch may stand,, but that of the
stones of a Gothic arch, composed of two parabolic seg-
ments, may be less by one twentieth ; the parabola of equi-
librium touching in this case the internal limit of the arch
In ptliers the at -j-Vir of its whole height above the abutments. If, how-
circular. ^\^x^ the arch is flatter, a segment of a circle will be some-r
what stronger than a pointed arch composed of parabolic or
elliptical segments. When the arch is higher, it is obvious
that a single circular curve is no longer applicable : and in
this case, it is of little consequence whether the segments
be circular or paraboSic, either of these forms approaching
sufficiently near to the curve of equilibrium, and both pro-
ducing equally a much smaller horizontal thrust than a se-
micircular arch.

TI.

Additional Remarks on the capillary Actions of Fluids. By
Aletes.

To Mr. NICHOLSON.
SIR,

Capillary ac- JL T has been observed, with apparent justice, by Mr.
Laplace, that the force of capillary action, other things
being equal, must be proportional to the square of the den-
sity of a liquid; and it is easy to deduce this result from

the

CAPILLARY ACTION.

25?

the demonstrations which vou did me the honour to insert Capillary ac-
in your 76th nuiuber. The area of the triangle A £ C ^'^^^ ^*^ ^"^^^*^
(Vol. XVill, PI. I, Fig. 8), which shows the magnitude of
"the cohesive force at C, is proportional to the square of the
line A C, representing the distance to which the force of co-
liesion extends; and if the same number of particles be con-
densed into any smaller space, the force will remain the
same, and it will still be proportional to the square of the
number of particles concerned ; or, in other words, to the
square of the density of the substance. The same remark
is also applicable to the tension of the common surface of
two lifjuids, or of a liquid and a solid; and this determina-
tion of the force ought perhaps to have been employed in
the investigation of '* the angle of contact of a solid with a
fluid"; but it is very singular that the result of this investi-
gation will 'be precisely the same, whether we proceed on the
supposition of a tension proportional simply to the difference,
or to the square of the difference of the densities. Thus if
the density of the fluid C B E (Fig. 6) be called «, that of
the solid B, b, and that of a second fluid, supposed to oc-
cupy the space C B A, c; if the tension be simply propor-
tional to the difference of density, we may call the force
acting in the direction B A, b — c, in the direftion B E,
a — bf alid the difference of these, 2 b — c — c, must be equal
to the force /« — c in B C, reduced to the direction B H, and
must be represented by the line B H, if a — c be represent-
ed by B C or \ B, A H being 2 6—2 c; or if A E be called
a — c, A H will be b — c. Now if, instead of b — c, a — 6,
and a — c, we take their squares, the difference of the first
twQ will be c c — a a — 2 ^ c -f 2 a bzz^lb [a—c) — [a a—c c)
" (2 b — ("a -f cj) . (a — t), which is to {a — c)^ as 2 b — a — c
to a — c, and B H will be to B C in the same proportion as
before." It is obvious that when there is only one fluid, and
c — o, AH must be to A E as 6 to «, upon either supposi-
tion.

The two suppositions are however not indifferent with re-»
spect to many other cases of the actions of capillary, forces, ■
Ihus if two liquids be capable of perfectly wetting a tube,
supposing both of them to be contained in it at the same
time, the whole weight supported by the force of capillary

actioiv

£ 5 21 C Al^IL t A|IY ACT^^p N.

Capillary ac- , ^iqtjon would b^ jtbe s^me as wliep the densest only is con-

Uon of fluids.

tainjcd in it, if the tension of the oommon surface were
simply as the difierence of the densities ; but it would be
always less, if the tension .werCj as the square of the differ-
ence. .■;,,,?...,-..,- ■. , ■

It is very easy tp determine this point by a simple experi-
ment. Take a clean capillary tube, about one tenth of an
inch in diameter, and iniaicrse it in water, so that about
Jiftlf .s^n iiich of itft^ej^tieij^^ty ciay renoain empty :• introdup?
slowly, with a bristle, a small quantity of oil in successive
drops, so as to form a thin coatinj^ on the water. It will
then be observed that the heij^ht of the fluid is very coiispir*
cuously diminished, andreduced to about thr-ee fourths, or
two thirds. Your readers* are not required to place implicit
faith in the anonymous statement of an experiment : they
may easily repeat it for thei;n selves ; and it is only adduced
in support of a cliain of reasoning founded on mathematical
analogy.

In this respect therefore it cannot be allowed, that Mr.
Laplace's second methoc] of considering the effects of capili-
lary action is, so perfectly satisfactory as it ap)pears upon a
cursory examination :.for both demonstration and experiment
are in direct contradiction to his assertion, that '* If tlie in-
dehnite vessel, in which the parallelopipedon is immersed,^
include-any number of fluids placed horizontally one above
another ; tiie excess of the weights of these fluids contained
in the tube, over the weight of the fluids which it would
bave contained without capilljary action, is the same as the
weight of th<? fluid that would rise above the level, if the
vessel contained only t^iat fluid in which the inferior extre-
mity of the parallelopipedon is immersed." Journal, Vol.

XVII, p. 291.

Upon these grounds we may infer, that if a great num-
ber of liquids, becoming insensibly less and less dense, and
the density of the last being inconsiderable, were contained
in the same tube, their capillary action would be wholly
destroyed: and it is not. impossible that the capillary forces
of various substances, of equal density, may be somewhat
modified by the more or less abrupt change of density at
their surface ; since there is reason to think, as we have al-
ready

CAPILIARY ACTION. £53

ready seen, tliut the density of all bodies Is a little diminish- Capillary ac-
ca\ in the neighbourhood of an cxpo?.cd surface ; and when ^^^" ° "* '

these bodies come into, contact with others, new varieties
may again arise, from tlie efi^^ct of the mutual cohesion ou
the superficial density.

We may also obtain, from this important law, a very dis'^
tinct idea of the manner in which a drop of a lighter liquid
spreads itself on a heavier :. the sum of the tensions of the
two surfaces of the drop being abrays smaller than the ten*
siort Bf the stirrounding surface.' When, however, one drop
has thu^ diffused itself, it leaves an invisible film on the
surface, which reduces the tension tOL an. equality with that
of the drop : and in this state of the surface, a new drop
will remain undisturbed. Thfe form of the lower surface of
the drop will be of the same nature with that of the upper,
its curvature being proportional to the height above a cer-
tain line, at which the internal and external pressure would
become equal. It cannot therefore happen, except by acci-
dent, that the surface of the fluid should remain perfectly
horizontal, although it may require a very nice examination
to detect its curvature. For example, in the case of oil
floating fon water, the tension of the surface of the oil is
only about half as great as that of the water, consequently
the tension of the common surface must be about one fourth,
or half as great as that of the oil : but the inclination of this
surface to the horizon, when the drop is thin, is more than
ten times as great as that of the upppr surface; consequently
the direction of the joint efl'ect of the tension must be in-
clined to the horizon in an angle about one fourth as great
as that which is contained by the surfaces of the drop; and
the contiguous surface of the water must assume a similar
direction in order to counteract this force : this will require
a shght depression of the drop, and consequently a slight
alteration of its curvature, but the general result will be the
same. On the supposition of a force simply proportional to
the difference of densitj'^ or of capillary force, a still greater
derangement of the general surface would, in this case, be
required : so that the phenomena of drops, floating in 'this
manner, have not, in fact, any tendency to establish such a
law, although they may appear at first sight to favour it.

The

254 ON D£ATH niOM COLO.

• »»

Capillary ac- The climinution of the effect of the tension of the surfaces
titni of fluids. r ^i i- • i* i i i- ■.. ^ i

of the drop, n\ consequence of their obliquity, appears to be

exactly counteracted by the force derived from the curvature
of the hoHzoiital aciion ; and the film left on the surface
Seems to occasion a resislahce to all motion, which renders
it thfficult to observe the slight mutual attractions of the
drops M'hich must arise from the mi^iule depressions that sur-
round them,

I am, SIR,

Your obedient humble servant,
\6 November. ALETES.

III.

On a Kind of Death j that may he presumed to be only appa-
rent: by Mr. Du Pont de Nemours. Read at the Jirst
Class of the Institute, Oct, 28, 1806=^\

:feffccts of heat J[t bas long been known, that the effects of heat and cold
to the body td ^'^''Y according to the nature of the bodit^s that are exposed
■which it is ap- to them. ExtrenK* heat is necessary to liquefy steel, plfl-
^^^ ' lina, or good porcelain : lead requires far le^s ; and a por-

tion much smaller still is sufficient for frozen water. On the
otliet hand, the degree of cold refitiisite tb render mercuiy
feolid is very great; u-hile that wliich forms ice is very mode-
rate.
Some vegeta- Among vegetables there are many, the living principle of

bles not killed ^v|,j(«h resists the stronsrest frosts, these only occasioning dis-
by the severest . " -^ . =*

frosts case in them, or, it I may Use the term, setting them asleep.

Leaves de- Our native trees lose their leaves in winter, without their
ctroye y i , stems being injured. Many of our herbaceous plants lose
and stalks: their stalks, though their roots retains their functions. There
but some roots are plants still more robust, which, after their roots have
ihouffh'frozcn. ^^*^'^ frozen in the ground, into which, the frost has penetrated
several feet beneath their ramificattons, revive notwithstand-
ing at the return of spring.

* Archircs Htfdralre.f, Vol, XIII, p. 8.

ON JDEATII FROM COLD. MSS

If WO proceed to animals, wc see the ant fall asleep in a Ant, fly, and

^, . , „ , , , ,, n 1- 21 , other insects,

very -slight degree of cold ; and the common fly does tlife ^j^^^ -^^ ^^^^'

same witii every appearance of being dead. Nor are these weather.

the only insects subject to this lethargic sleep.

In the class mammalia we have dormice, marmots, a r>d In some of the:
othef sleepers, in which life appears to be suspended, when ^j^ended. ' *
cold weather comes on. This suspension f)f life is so com-
plete in'some of the species, that iheir heart Ceases to beat
for whole months.

The snail and the toad undergo the same stupefaction. Snail and toa^i.
Several serpeiits exhibit a phenomenon still more surprising:
they can be frozen so as to become brittle, and die if they Serpents may
be broken in this state; but if they he left in their holes, ^.'ifbefn'ykili'
into which the warmth of spring penetrates by very slow dc- led.
greos, they revive, and give proof tliey were not dea/I.

it IS in the season when their food begins to fail, when the Little fructivo.
fruits and herbs on which they fed disappear, after having sleep firlT-^ *
fattened them by their temporary abundance, and in this fat
supplied them with a narcotic to induce sleep as well as food
to support them while it lasts, that most of these little dc-
vourers conceal themselves to sleep, and cease to atford prey
to the larger devourcrs their enemies, wliich in their turn lose then the larger
thought and motion. ^ carnivorous.

Those that would be deprived of food by the snow cover- They sleep

ing it, sleep till the snow melts, and a little longer. Perhaps ^^'1^''^ ^l^eir
^ . •/ 1 , • , I • 1 't . ,- , food is wanting,

for a similar reason the white bear, which lives by fishing on rr

, . 1 , t • , 1 . Hence the

the seashore during the summer, and on the islands of ice in white bear re-
autumn, does not fall asleep till the ice united, thickened, ^i^es later than
. , , . , . . , , the black bearj

and raised too high above the water, is no longer the resort

of the seal. His means of subsistence continuing longer, a
much severer cold is requisite to deaden in him the call of
seeking it, than in the black bear in the first place, a great
devourer of honey and vegetables, and next in the brown ^^ ^y^j^ ^^^^
bear, which lives on animals that winter drives into their re- the browji.
treats before him.

That hunger should cease in these animals at the period p^^ jj .
when faniine would take place, and in consequence of the ordered it thus,
same degree of temperature, is certainly a great benefit con- lhe!n*^froin
ferred on them by that luteiUgcncc, which regulates every starving,

part

256

ox DEATH FROM COLt>.

part of the UHiversc. If they retttine(J their energy, they
wouhl peribh from inanition. They are unacquainted with
want; they feel not its pains; ihcy incur not its danger*
Nature saves theni from it by that axiom, which has b,een
fedunJumfo^^ ^^ ^ i^^^' he who sleeps, dines. I'hc state of

iood. .sUipefaction, in which their vital principle takes refuge as

long a§ the cold and its companion want continue, occasions
This stupor them no uneasine.s:, : it commences even with a sensation of
but pleasurable, tranquil enjoyment, a sensation not unknown to ourselves.
Notadisease, . It is certain, that being thus benumbed is not even a dis-
ease : that the drowsiness, which brings it on, is pleasurable:
but friendly to that sleep is an asylum, in which life fortifies itself, expend-
^'^* ing less, and husbanding its resources: that it is even a pro-

tection from the injuries as well as from the^ pains of cold :

and renders the and that it renders living bodies more capable of retainino-
body a woise l - i i- • • i • ^i • i ,• ^

cbnductorof "^^^^ by diminishing their conductmg power.

heat. When the Cold increases with too much violence, man be- ■

When our comes insensible to it. If one of his limbs freeze, he does
we areinsensi- "^^ perceive it, till he is informed of it by others*. On the
ble of it. contrar}', he fancies himself at length growing warmer; and

Effects of ge- jf no one of his limbs be more affected than another, his
state seems pleasurable : he feels a seducing and delightsome
propensity to sleep: he is angry with his friends, who urge
him to walk on, and prevent him from indulging his inclina-
tion : he intreats them, to let him close his eyes for a few
moments; and if they yield, he falls asleep, and appears
dead like a dormouse.

His death in Let US venture to suppose, that he is not more dead in

this case only .. _, . i , . ■ ^i • 1.1 i 1 1

apparent, like reality. There is no doubt in this case, but he would sleep

that of oiher Jike the dormouse, deprived of thought and of apparent vital

action, at least as long as the same temperature continued,

though it may ^^^ ^^^V ^^^'^ presume, that he would really and completely

end in extinc- Jose his life at the expiration of a certain time, if he received

tion o 1 e. 210 succour : for instance, after his fat was consumed, if he

were not frozen a'S^well as asleep; or after the habit of the

vital functions had been entirely extinguished by a frost too

severe/ or of too long continuance, so as to stop the ahmeu-

* This is very eommon in Poland and Russia.
^ tary

ox DEATit FTcOM COLD. ^ S,57

tary transfusion of the fat, or stiffen the organs to such a de-
gree, as to cause an absolute cessation of their secret move-
tnents, which appears to be an accident that the mamTnalia
are liable to, though some of the serpents and gelatinous ani-
mals are not.

This important point, that the general vitality of man is Wemayinfe?

mcrelv suspended in this case, is indicated by the repeated t^»s by reason-
-> r ' . . mg from a part

experience of northern countries and lofty mountains with to the whole.

respect to the particular vitality of frozen limbs.

It is by no means uncommon for the nose, ears, hands, or EfFect of cold
ifeet, to freeze in cold climates. If this be not quickly re- °"^^^ ^'"S^e
medied, the contrast between the living state of the rest of
the body and the incipient xieath of the limb attacked occa-
sions this limb to sphacelate : Nature cuts it off by the stre-
nuous resistance of the. contiguous and threatened limb. If
hasty means be adopted to remedy it, the too rapid distension
of the capillary vessels by the fluids contained in 'them rup-
tures their sides, and extravasations take place ; the commu-
nication, instead of being restored, is thus completely inter-
rupted, and a gangrene is induced from the same cause. The Effects on ve-
same thing happens to those buds of plants, that are exposed p^^^^^s sirai-
to the rays of the sun, befoie the frost that covered them has
been dispersed ; while those that are thawed gradually in the
shade receive no injur3\ " Nature," 3a3-s the great Newton,
** is consistent with herself." In all things, and at all times,
she follows the same laws. The more she is observed with a
philosophic eye, the more we perceive, that these laws are
few, alid combined with admirable, with astonishing benevo-
lence.

It is the same then with the limbs of animals, as with They must be
those of vegetables. If they be thawed with cautious slow- mlnishing th«
ness ; if the part frozen be removed from the extreme cold it ^^^^ ^Y slo'w
has experienced to a less degree of cold ; if it be rubbed ^"^^ * ^^"^'
with snow, then immersed in the water of melting ice, and
this be suffered to warm gradually, at first by the mere con-
tact of the contiguous unfrozen portion of the limb, the part
frozen will recover its local vitality. The cure may then be
completed by very small successive additions of water a little
Vol. XVin— Dec. 1807. S warmer

258 ^^ DEATH TROM COLD.

warmer than that by which the part was thawed, and thus

the limb be saved.
Similar treat- It is agreeable to all analogy to believe, or at least to sus-
probabTy^suc- V^^^f ^^^^ ^^hat thus happens with complete certainty to
cred when the every limb, lender such circumstances, must also take place
nerd!°"'^^^" ^^'^^ respect to thcwhole of the limbs, if the same or still

greater precautions were observed, if the delay of succour

be not too long, and if its application be not too rapid.

There are Instances of effectual assistance being given to men, either

many facts m gj^tirely frozen, which however is perhaps doubtful, or at
support of this. J » II >

least profoundly benumbed, have occurred frequently in our

glaciers, and are mentioned by our colleague Ramond. Hal-
ler regrets, that no means were tried with a man, vvho was
thrown up by a torrent of melted ice long after he had been
buried under it, at least as far as could be judged by hi*
dress, though his skin was not in the least discoloured.
Tortal's me- Our learned colleague Portal, in his excellent work on

thodgood, asphixies, points out for that which results from cold a me-
thod of treatment founded on very good principles ; but I
but too hasty, am apprehensive it would be found too hasty in its progress,
as it is more so than that emplo^^d in the case of a single
Should be limb, and it may be presumed than a general aftcction, being
than in a mere more serious and formidable than an affection merely local,
local affection, njugt require still more circumspection in the progressive gra-
duation of the means employed : the rupture or even aneurism
of a few vessels might have much more fatal consequences in
Hjis case.
The path is Be it as it may, it is evident, that the first steps are al-

opened: ready taken toward a constant and complete theory of the

effects of cold on plants and animals, in respect to the degree
of temperature, that suits each species. But if this new
branch of the beautiful stream of knowledge be opened, and
begin to excite our attention with advantage, we must con-
but not suffi- fess, that it has not hitherto been sufficiently explored ; that
T^^ilf ^*" of the important phenomenon of the life or death of men
frozen or simply laid asleep by cold we know nothing certain-
ly, either with respect to the periods or the physiology of the
transition from one of these to the other, the succession of
•means to be employed for the preservation of those whose

lives

ON DEATH FROM COLD. 253

lives are thus endangered, or the path to be pursued for the
advancement of our knowledge of them.

Experiments have not been repeated sufficiently or with Desiderata,
due regularity: they have neither been as scientifically di-
rected, nor as scrupulously described, as the case requires.
It appears to me therefore an object worthy the attention of
the class, to point out these experiments; to indicate the
proper path of inquiry with a view to improvement ; to as- •
certain,- whether man be in fact, like the bear and the mar-
mot, an animal that cold benumbs and lays asleep without
killing; whether it be true, that he can endure being com-
pletely frozen like the serpent ; and whether in this extreme
case a gently graduated warmth, applied in time, and slowly
developed, would restore life. This might throw a great
light on the question, which Drs. Herholdt and Rafn have
yet treated but in part, and the term of which you have pro-
longed.

We see that several animals destitute of vertebra?, among Difference in
those with vertebrae serpents, and among the mammalia a ani^aU.^
great number of the smaller species with cutting teeth, sleep
three or four months, or even more, in a ^-ery moderate de-
gree of cold : that a greater degree, and this in different pro-
portions, is required for the several species of bears, the sleep
of which too, in this state of imperfect death, does not ap-
pear to be so profound, or the suspension of life so complete:
that man falls asleep in a still greater degree of cold : that it Man.
is more than probable, nay almost certain, that judicious "
means, prudently adminbtered, would be capable of awaking
him from this dangerous sleep, so near akin to death : and
that it might be the same with other animals, or, indeed, Perhaps all
with all animals, that are rendered torpid only by a degree be^rendere?

of cold still greater than that which deprives man of the ap- torpid by cold,

c 1-r and recovered.

pearance of life.

Every particular, even to the minutest, that the respect- The minutest

able monks of St. Bernard, and the guides to the glaciers of shouW bf coL-

the Alps and Pyrenees, can give, should be collected. I lected.

even think that the class would do well, to call the attention

of all the learned to this subject, and particularly to invite

the four academies of Europe, that are best situate to pur-

S 2 su»

250 DESCRIPTION' OF AN AIR ENGINE.

sue it with success, those of Petersburg, Wilua, Copenha-
gen, and Stockholm, to investigate this point of natural his-
tory.
Wars have no- To this political circumstances can be no obstacle. There
wl'hfilies^i- ^^ never \var between the learned, between academies. Nei-
ences. ther our emperor nor the kino; of England has disapproved

your communicating with the royaj society of London for
the interests of the sciejiccs. Scientific voyages have been
respected by both parries. In the electorate of Hanover the
university of Gottingen was protected by our army. The
republic of letters, that great and noble benefactress of all
polished states, ever preserves its honourable and friendly
neutrality.

Suspended Already many of those who happen to be drowned, orsuf-

animation of r ^ ^ , , . ., . ,,> „,.

drowned and located by carbonic acid, are. restored to life. Ihese arc

suffocated per- two provinces, which Humanity has conquered from thft
sons- already . /• tn i ^ ' . . . ^ , . , . ,.

testored. empire ot Death at the two extremities of his domain: for

these two diseases, so long considered as deaths, are totally

different in their nature, and require opposite means of

cure.

Those princes, who dispute with each other the territories

of the living^ see with regret by how many murders they

must be purchased : they would be the first to encourage the

peaceful labours and fraternal correspondence, that might

conduce to recover from the yet' doubtful bonds of death a

third class of its victims, men benumbed by frost.

IV.

Description of an Engine for affording Mechanical Power
from Air expanded by Heat; hy Sir George Cayley, Bart,

To Mr. NICHOLSON.

Sir, Brompton, Sept. 25, 1807.

E^^pan^ion of JL Observed in your last vol. p. 368, thatsome experiment*

air by heat ^^^^ 1^^^^^ lately made in Fiance upon air, expanded by
considered as a •' ^ , '^ .

first mover. heat, applied as a ^rst naover tiar raechamcal purposes. 1 his

idea.

yiSwUvtU- Ffutos. Journal. Vol.Xi'llL nvilp. 2i
Sir Gee. Cini^'s E\xpanjioTv Ji;r Fngirn

^ n /

?fyvemloffigt^ Electrmneter

DESCRIPTION OF AS AIR ENGINE. g^l

idea, as you justly remark, is by no meaps new in this
country; yet I have not heard that ^ny successful experi-
ments have been made, exclusively upon this principle, in
England, though you hint that something promising has
been accomplished relative to it.

The subject is of much importance, as the steam engine its advantages*
has hitherto proved too v/eighty and cumbrous for most
purposes of locomotion ; whereas the expansion of air seems
calculated to supply a mover free from these defects. Under
this impression I send you a sketch of an engine I projected
upon this principle several years ago,^ it was made on a con-
siderable scale at Newcastle, though I must confess without
success in the result, which T attributed to the imperfect
iilanner in which it was executed, the cylinders being made
of sheets copper, and so irregular, as not to be rendered
tolerably air-tight bv any packing of the piston. I think
there can be no doubt that the scheme is practicable in some
way or other ; and I conceive that the form of the engine here
sketched will be the basis of whatever experience may prove
to be additional requisite to perfection in the apparatus of
the air engine.

A and B, PI. VIIT, fig. 1, are two cylinders, placed one Description of
above another; C and D, their respective pistons connected an engine;
by one rod. F is a cylinder, containing a fire in a vessel btowhie cy^lir^
within it in such a manner, that any air passing between the der & a work-
upper and lower portions of it must go through the fire. ^"^ '^^^'^ '^'^*
This vessel also contains a long cylinder, open at the bot-
tom, and directly over the centre of the fire, for the purpose
of holding coke or other fuel. This cylinder is covered at
the top, and packed air-tight when it has served the purpose
of permitting the fire to be kindled through it : and has been
filled with fuel.

The cylinder B is fitted up to answer the purpose of a
double stroke forcing pump, or bellows, to drive the air into
the upper portion oi the vessel F, from whence it passes
downwards thi-ough the fire for the purpose of consuming
the smoke (the fresh fuel being supplied from the reservoir
above) in its passage through the more completely ignited ■ -^f*"^

cinders below. In this act the air is expanded; and, by
means of pipes from the low6r portion of F, it is conveyed

alteriiately

25^ , DISEASES OF WHEAT.,

alternately above and below the piston of the cylinder A.
In f ach pipe is fixed a stop cock or valve, so constructed as
to open a passage to the external air, when it shuts the con-
nexion with the fire vessel. These cocks are worked by a
plug frame.

From this construction it will appear evident, that what-
ever expansion the air receives, its pressure will operate alike
upon the piston of the bellows and of the receiver; and
that always in opposition to each other : Hence the power of
the stroke will be in proportion to the excess of the area of
the receiving piston, over that of the feeding one, multiphed
by the expansive force of the contained air, and by the
length of the movement.
The engine If, when the engine is well constructed, the expansion of

maybe usRd for ^},p ^j,. \^ keeping up the fire be not found sufficiently sensi-
p^ed water. b^^> ^^'^^ *^^ form of the engine is such as to admit of either
inflammable gas, oil of tar, or other inflammable matters,
being injected, each stroke, upon the fire; so that all the
heat generated by the united combustion may operate
without waste ; perhaps even a slight sprinkling of water,
either upon, or round the sides of the fire, might answer the
purpose. It scarcely need be observed, that a tube con-
nected with a small forcing pump are the only things re?-
c^uired for producing these effects.

I remain, Sir,

Your obedient Servant,

GEORGE CAYLEY,

A Letter from Mr. Rob«rt Harrup to the Editor, on ike
Diseases of Wheat,

To Mr. NICHOLSON.
SIR,

Keference to JLn a former communication on smut in wheat, inserted ia

the author's you|. Journal last year, I gave an account of some experi-
former paper. ■^ , , , . . , i. i i-

inents which proved, that the principal cause oi the disease

DISEASES OF %HEA.T. Q63

IS smut mixed with the seed, and that although the diseased
grains do not ves^etate, they produce smut cars in the crop.
It was also shown, that the seed corn prepared with lime
})revented the disease from proving injurious in any consi-
derable degree. At that time my observations led me to
conjecture, that aninialcula might probably be the primary
cause. By reasoning from analogy, it still, however, re-
mained doubtful, whether these minute creatures might not
be the eifect rather than the cause of the disease ^ I there-
fore resolved to attempt an analysis of the smut itself.

From various unexpected circumstances I have been pre- On the cause
vented completing the inquiry, and am at present only war- ^yi^gat"
ranted in announcing, that o«e of the component parts of
srniit is the sole cause of that destructive malady, and that
wherever it exists, whether in the seed or in the soil, the crop
\vill be tainted. My chief motive in forwarding you at this
/f we what may be deemed a- premature communication is,
to earnestly recommend to all practical agriculturists the
following receipt for the preservation of seed wheat.

Put the wheat gradually into limewater*, at the same Receipt for
time carefully taking off the light grains which float on the P'-ep^nng seed

API- 1-11 wheat. — Soak

surface. After standing covered with the water to the depth it well in lim«»«

of five or six inches, and the vessel closely shut durins" 7^*^'^' ^}^^^

^r. 1 ... . , . . , . ^ keep It for

twelve or fitteen hours, stirring it twice or thrice in that time, some hours in

the liquor is to be drawn off, and the wheat put on a floor, 'i'^i*- <^ water.
The following mixture is then to be poured regularly over w^q powder,
it, viz^ Lime, five pounds; boiling water, three gallons; stir ^"^ '^^^^
them together till the lime is reduced to a powder, which
will happen in a minute or two. It is then to be intimately
mixed with the wheat, which after lying covered with cloths
for some hours may be dried with lime in poSvder, and im-
mediately sown. The above quantities are sufficient for hve
bushels of grain, and more ought not to be prepared toge-
ther.

• Limewater is made by mixing (boiling) water and quicklime toge-
ther, about one pound of lime (more or less) will be sufficient for three
gallons of water; and, -after standing ah hour or two in a covered vessel,
pouring off the liquor, which, if not immediately used, must. be. kept
in a vessel closely shut.

There

g64 DISEASES OF WHEAT.

An alkali There can be little doubt but either of the iixed alkalis

bly^haveUKT" ^^^^^ ^^^'^ ^^^^ ^^"^^ ell'ect as the lime; but as they are no<v
effect oflime. under trial, I do not venture to recommend them till I am

certain of the. result.
Other diseases Althouj^h smut is the most destructive, yet there are other
o ^K eat. diseases incident to wheat, which are sufficiently injurious
tp deserve attention. 1 shall therefore take the liberty of
making a few observations on each of them.

In the second edition of Adams's Essays on the Micro-
scope by Kanmacher a description of animalcular eels is
given, in what is there called blighted wheat. The grains
are said to be blackish, and contain a white soft substance^
which separates into numerous filaments when put into wa-
ter.
Account of tlie Needham was the first who discovered, that each of these
eels in diseased filaments was a living creature. He sent some of the grains
eorn. to M. Folkes, Esq., at tliat time president of the Royal So-

ciety, with an account of his discovery. They were deli-
Tered to Mr. Baker for examination, who after repeated
trials could discover no other motion than a separation of the
fibres or threads, which he imputed wholly to the elasticity
in them; and perceiving no token of life, after watching
them with due care and repeating the experiments, an ac-
count thereof was sent to Needham, who from his own trials
fmind out the cause of failure, and advised him to steep the
grains before he attempted to, open them. This method
proved successful ; and at different times after this Baker
made experiments with grains of the same parcel, without''
being once disappointed. He soaked a couple of them in
water for the space of thirty-six hours, when, believing them
sufficiently moistened, he cut one open^, and applying some
pf the fibrous substance to the microscope in a drop of wa-
ter, it separated immediately, and presented multitudes of
the anguillulae without the least motion or sign of life ; but
being taught by experience, that they might notwithstand-
ing possibly revive, he left them about four hours, and then
examining them again, found much the greatest number
moving their extremities pretty briskly, and in an hour or
two more they appeared as lively as these creatures usually

are.

DISEASES OF WJIEAT. ^65

&rei These grains were four years old at the time the exper
riuients were j^iiade.

M. Roffredl sowed some of the grains, which sprung up; The diseased
but the ear was either wholly or in a great measure spoiled, g^^^'J ^aj"d\ad
being filled with these eels. He ^Iso found^hem in other the same kind
parts of the plant. In order to diseu^age which, it must ofanimalcula.
he soaked in water, and then compressed a little. At first
sight they seemed to resemble the foregoing; but a more
accurate inspection showed, that they were difiierent in struc-
ture, and much more lively than those which were procured
from the dried grain. They also increased ia size in a cer- . .

tain proportion to the plant, so that at last they were ob-
served with great ease by the naked eye, being two teriths of
an inch long, and nearly one teiith in diameter.

This disease, which i am informed is known by the name The disease is
of ear-cockle, or, in some parts of the country is called cockle cr ^***'
burnt-wheat from the appearance of the grains, claims parti- burnt wheat,
cular attention, as it is by no means uncommon, and never
fails to prove highly injurious. I saw a field of wheat the
present season, in which ears of this sort were so abundant,
that it could not be worth above one third of the value had
it been clean: and I have heard of several more.

The cause seems to be either in the seed or in the soil, or inquirv re-
perhaps both contribute ; but it seems by no means to be speciing its
influenced by the weather. On a superficial view, the ears *^^^^*'^*
have much the appearance of those of smut, but on closer
examination are found to be very different. The grains,
before they are ripe, are t)f a dark olive green colour, not
exactly the shape of sound grains, and contain a white soft
matter, which does not fill them exactly. When at matu-
rity they are black, and by keeping become considerably-
harder than common wheat, and have much the appearance
as if they had been scorched. When they are opened in
this state, th6 black hard crust is found to be about one
third of their thickness, surrounding the white substance.
The white matter is the anguillula^, as mentioned before.
By viewing them with a magnifier before they are removed,
they have somewhat the appearance of very fine cotton fibres
coiled together, and no motion is perceptible amongst them.
But if a recent grain is opened, and a few of them taken

out

S66 BtSEASKS OF WHEATU

out on the point of a qnill, and in that situation examined
by a baud mtignilier, a slow yet very perceptible motion in
every direction may be seen in the extremities of those that
do not adhere closely to the main body." Indeed they seem
to be inctvpable of motion in any great degree till put into
water, being glued iSVgether by a visctd matter. When taken
from the recent grain and put into water, they are seen t#
"use every exertion to disentangle themselves, which is gene-
rally a work of time.
Life of the ani- It would appear from these facts, that they enjoy exist-
jnalculu in the ejice while enclosed in their dark cells; and probably the
gram, &c. ,, i • i i i . , . ,

small space which they do not occupy m the gram, and

which appears empty, is designed to contain air, which I
believe is absolutely necessary to the existence of eveiy crea-
ture however minute. It also appears, that when the grains
become dry animation is suspended, and continues so till
moisture is again added.
Suspension of That animal life can be suspended for four years at least,
aiuma i e. ^^ appears from the experiments of Baker, already noticed,
and how ranch longer we know not, and be then restored
by a drop of water, must ever excite wonder and admira-
tion. The reason why Baker failed in restoring life by im-
mediately putting the anguillulse from the old grains into
water seems to be, that the sudden ap[i\\c3.tion of that fluid
was too much for their delicate frames, for when the grains
were previously soaked, so that the water gradually pene-
trated the containing crust, he succeeded.

Grains eight or nine months old do not require to be
soaked, as the anguillulie will revive in a few hours, when put
immediately into water. ,
The author I repeatedly sowed some of this diseased grain, but never

never succeed- succeeded in raising a single plajit, nor even in producing
any plant from the least appearance of vegetation. Indeed I had little ex-
this dweascd pectation of success, for the whole of the substance con-
tained in the seed consisted of animalcula, excepting a very
minute portion of fiocculent matter, which could only be
discovered when in water. I took up some of the grains
after lying in the ground upwards ot nine weeks. Several
of them were empty, and others contained a few of tlie an-
jujllulae, whiiji mo\ed briskly the instant they were putint^

water-

J)ISEA^ES OF WHEAT. Q^f

water. One of the grains was tilled with a brownish sub-
stance fall of perforations, from which issued small worms
discernible by the naked eye. They continued to live in
water, and upon examination corresponded in all respecta
with those seen by Roffredi in the plants which he raised.
Since that time I have opened several recent grains, which
contained a few of this sort, as well as the anguillulae. They
were more than twice the diameter, and about the same
length. Perhaps the grains which vegetated with Roffredi
might not have been so much diseased as those I sowed, for
that some are only partially infected I accidentally disco-
vered. The first parcel I procured were only blackish on
one side, and contained very few animalcula. The rest of
their contents a])peared similar to that of sound wheat, ^^t he think*
There can therefore be little doubt, that had they been it possible and
sown, they would have come up. However that may be, it
is certain they do vegetate, for I have since that examined
several roots of this diseased wheat, and frequently found
the grain from which they sprung to be similar to that in the
«ar.

None of the anguillulee 1 examined exceeded the two hun- Examination
dredth part of an inch in diameter, and they were in general oftheanguillu-
about twenty-six times that length. When viewed with a croscope.
hand magnifier they appear of a silvery white, but when
placed in the microscope under a highly magnifying power,
they are of a bright chesnut colour. A row of transparent
globules, placed at regular distances, run down each side of
the body till within a third of the extremities. Last winter They are lonj^
I preserved an immense number of them three months in a ^^^^^>
watch glass, by frequently adding fresh water to them.
They did not increase in size, neither were they changed in
any respect. If they are not endowed with sight, they are and affected by
at least very much affected by light. When placed in the ^'Sl^'*
rays of the sun, or in the light of a candle, in a minute or
two they run together into one or several bunches or knots,
and continue so for some time. This effect is most distinctly
viewed by means of the solar microscope. When placed in
that instrument, they are seen floating from every part of
the fluid to form themselves into an apparently inextricable

bunch,

2g3 DISEASES OF WHEAT.

bunch, and those which arrive last use every exertion to bury
theniHelves amongst their companions. ' "*

Many other particuhirs velutin<^ to them mi^ht be stated^l
but as the subject seems not to lead to any purpose of uti*
lity, 1 shall close this account of them by mentioning two
facts, which may be of advantage to be known. — They are
instantly kilfed by adding' a few drops of limewater to the
water coritaining them. And if the entire grains are steeped
in limewater from twelve to ttveuty-four hours, the anguillulee
they contain are incapable of being revived, either by placing
them in fresh ivater^ or by any other means. The evident
inference from these facts is, that the same preparation^
\vhich has been recommended for the prevention of smut will
also prove effectual for ear-cockle.
The great va- An experimental inquiry into the nature, causes, and cure

lue ai.d im- ^f the diseases c/f corn won hi prove a valuable acquis" tiori ; in-^
ponance of in- , , ., . . . - ■, • i • ^ . i

quiries into the ^^^^ it is surprising, considermg the impo:tHnce of the sub-
diseases of ject, that notliing of thit:^ kind has been attempted. Sir Joseph
Banks, in his Short Account of the Cause of the Disease in,
Com called by Farmers the Blight, &c., published in the be-
ginning of 1805, presumes, that the want of actual observa-
tion will be abundantly supplied by those, "whose leisure and
residence in ihecountry enable them to examine, not only
the progress of the crops, but the origin and advances also
of all those obstacles which nature has opposed to the suc-
cess of agricultural labours.'' We have still to regret, that
the expectations of that justly celebrated philosopher have
been hitherto disappointed ; for 1 believe little or nothing
has been given to the public on the subject since that timie.
Two species of From the few observations 1 have been able to make on
funjii in the the blight, it appears, that the parasitic fungi which occa-
" sion it are of several difl'erent species, and that none of them

are particular!}" injuiious, except the dark coloured, such as
that which destroyed the crops in 1804. I was never able
to discover, that the orange coloured, which appears early
in the summer, was the dark coloured in an immature state.
the yellow and On the contrary, I have always found them ditlerent ; the
the dark. yellow changing to a dirty ash colour as it approached to

decay, and the dark coloured continuing unchanged from'
its first appearance. In tlie summer of last year I carefully

examined

DISEASES OF WHEAT. fl|69i

examined a number of wheat fields at different times, and
found tlie' straw untouched by the blight, and in every re-
spect in a healthy state. Every thing continued to have a
promising aspect till the heavy rains which fell a few weeks
before the eommencemcnt of harvest; the dark coloured
blight then began to show itself, and continued to spread
considerably ; and, if we may judge from its progress, had
the cutting down the crops been delayed a fortnight or three
weeks longer, it would have proved equally destructive with
that which took place in 1804. A sufficient number of facts ' ^

is yet wanting to warrant any conject'.ire on the manner in
which the fungi were produced by the heavy rains; however,
we may be pretty well assured, that all diseases which de-
pend so much on the state of the atmosphere, must ever
baffle human ingenuity to prevent. The earlier the crops
are ripe, the less liable will they be to be injured, and the
only remedy at present known is, to cut down the crop when-
ever the blight begins to make any progress.

Although the above are all the principal diseases of wheat, Appearance of
at least as far as my observation goes, I cannot take leave ^^tiy prrished
of the subject without noticing a very common appearance plantsinacrop
in wheat crops, which is more or less frequent every season, ^ ^ ^'^ *
and varies considerably in different fields. Some time after
the corn is come out in ear, but yet in a green, unripe state,
we frequently observe several plants entirely white, with
every appearance of having perished. As harvest approaches,
and the corn changes to a bright yellovv, these plants, par-
ticularly after rain or heavy dews, put on a blackish appear-
ance, as if sprinkled with a black powder. Upon examina-
tion by the microscope, this appearance is found to be occa-
sioned by innumerable tuffets of a parasitic plant growing
out of the poies of every part of the plant which is exposed,
to the action of the air, very much resembling some species
of the plantulae of mould ; even the sap vessels of the stravr
are frequently filled in different parts with a black substance, «
easily discernible by placing the straw between the eye and
a strong light. The grains, as might be expected, are small
in size, and of a reddish brown colour. Most probably this
affection arises from some dcQay at the root, but whatever
that may be I have not hitherto discovered.,^. I, have fie-

/ ' quently

I

j270 PORTABLE ELECTROMEfER.

quently examined the roots with attention, both in an entire
state and when dissected, but could never perceive the
smallest difference between them, and those of healthy
plants.

With the hope that the subject will be further investis^ated
by those whose leisure affords them opportunity, and whose
abilities are adequate to the inquiry,
I remain, SIR,

Your obedient humble servant,
Chohham, Oct. 1, 1807. ROBERT HARRUP.

vr.

Description of a simple and convenient portable Electrometer
for Mineralogists. In a Letter from a Correspondents

To Mr. NICHOLSON.
SIR,

trometer.

Portable elec- JLjOOKING over Brongniart's Treatise on Mineralogy,
lately published at Paris, ft appeared to me, that the elec-
trometer he has figured and described for the purpose of de-
tecting electricity in minerals deserves to be better known
than I imagine it is ; its simplicity rendering it very porta-
ble, and always ready to use, without being liable to be out
of order. If you entertain the same opinion of its conve-
nience to the mineralogical traveller, perhaps you may find
a corner for it in some plate or other of your valuable and
useful publication.

I am, SIR,

Your obliged reader,

O. N.

Method of de- To discover the production of electricity in a stone by
^^TV'' ft^^^^"' heat or friction, it is brought near to either end of the slen-
der brass needle, a h, PI, VIII, fig. 2, and whatever kind
of electricity the stone has acquired, it will make the needle
ttiove, if this be done with proper precaution.

. But

ITEVT ROTATION OF GROM. 27^

But to distinguish the kind of electricity developed in the Mode of dis-
-i-iii !• 'i tin^uislnng
Stone, the electronaeter must be insulated, by placing it on whether it be

a cake of resin, and positive or negative electricity may be posiuve or &«*
commuuicated to it in the following manner. Place a lin- ^
ger on the metallic base c of the electrometer ; and bring
within a proper distance of it a rod of glass, or resin, e^
electrified by friction. When the instrument may be pre-
sumed to be charged with the kind of electricity desired,
withdraw first the finger from the base, and then the rod of
glass or resin. The stone being then presented to one of
the knobs of the electrometer, a or h; if the stone repel it,
the electricity it possesses is of the same kind as that im--^
parted to the electrometer; if it attract it, it is of the oppo- ^
site kind.

Some stones communicate positive electricity to the .resin Soma stone*-
on which they are rubbed. To discover this, property, a ^o^tTve^g^ec-
piece of sealing wax may be flattened on a smooth substance, tricity to resia
and the stone rubbed gently on this plane surface. The ^^^ "ictjQa*
)cind of electricity the resinous matter has received may then
be found by means of the insulated electrometer.

VII.

A Method of Sowing Clover, and a new Plan for a Rotation of
Crops; by Mr. de V is cess, of Thcde, near Clermont*,

T the end of winter, after the hard frosts are over, and Clover sowe4
when the weather is dry, I sow twenty pounds of clover seed ^^ ^^^
on a septerce of land, about l^OO toises [2500 yards] in cir-
cumference, sowed with rye the preceding autumn. This
seed is harrowed in with a common wooden harrow, which is ^nd harrowei
drawn all over the field by a pair of oxen. Instead of in- ini«
juring the rye, this harrowing accelerates its growth, and it
actually affords a finer crop than rye that has not been har»
rowed.

When the rye is ripe, I cut it in the usual mode ; and

• Sonnini's Biblioth. Physico-6cQnomique, Oct. 1807, p 14.
^ when

^72 ^EW ROTATtON OF CROP^.

tvhen it is cnrried, the clover forms a green sward interniixcd

witli yellow stubble.
CTrtyer mown The clover may be mown in September the same year;
andcnitlc^um- ^"^ cattle may afterward be fed on it till the frosts come
ed on it. on, without inconvenience.

2d year cut The second year the cjover will be in its most productive

three or four state J it maybe mowed at least three times for hay, or four
then pastured ^^r green foflder; beside which it will afford an abundant

pasture till the frosts come*.

2d year cut The third rear I mow it but twice, and when it has shot

t\vice,and then ■,• ^ n i t. • t i • • -it

ploughed ill. "P ^ httle alter the second cuttmo^, I plow it m with the

simple plow of the eountry. I afterward plow and harrovr

it repeatedly, till the land is brought to a proper tilth for

jye or wheat, which I sow without any manure.

CloTcranatu- j^ is to be observed, that clover is a natural manure fof

ml manure for . -mi

wheat, wheat; that, as is well known^ a i^ood crop of wheat may bt.

had any where after a good crop of clover; that the wheat

particularly vvill be so much the better, if the clover have been dressed

-nith plaster of , ,. . . , ^ r i r rt •

Paris, the precedmg spring with 2 cwt. of plaster of Fans to every

quartelee of 300 toises scattered over the surface.
Wheat after Wheat succeeds veryAvell after clover without plaster or
clover requires ^^ ^^^^ other dressing, but it is indispensable to weed it, and

for want of hands I shall in future prefer rye, which when

once sown requires no farther care.
Advantajres of To prove the advantage of my practice in every respeet^
■s practice, ^jjjggj.^^^ ^)^^^ ^^^ ^y^ | ^^^.\\ manured I sow my clover in the

spring. This clover costs me nothing either for ploughing or
manuring ; but only the price of the seed] and the labour of
sowing and harrowing it].

A septeree of clover furnishes me, beside the feed at the
end of the first and second years, at least five crops of hay
during the two jxars that it wholly occupies the land.

Rotation (dt * If the farmer would adliere to the order of cropping where corn is

com eveiy sown every other year, he must plow in the clover after the second mow-
other year. .^^^ ^^ ^^^ y^^^ '

Rye better t ^ prefer sowing clover on rye to sowing it on oats, in the first place

than oats with because; the crop of rye is more valurbic, and in the next because expe-
clover. rience has convinced me, that the clover is mure forward ; no doubt be-

cause the rye being already at somo height, it germinates and grows more
advantageously under its shelter, particularly in dry seasons.

Calculating

NEW UOTATION OF CHOPS. Q^

Calculatiiiff efach croi) to mve me a ton of hay, at £2 10s. a Average price

,. , • 1 1 .- xu- ij ofcloverhay

ton, Its niedmm value since the revolution, this would pro- -^^ y^^^ce

duce me £l2 10s. for the two years, at the expense only of £2 lOs. a ton.

the seed, mowing, making, and carrying.

To this considerable return may be added the saving of A fine crop of
dung for the rye or wheat sown immediately after, and a tine 'Ji^i^^^y^^^^
crop of which is certain ; if no unforeseen and irremediable nure.
accident, as hail or frost, disappoint our expectations.

After this first crop of corn without dung, I immediately Rye.
sow rye, manuring it well.

As soon as this crop is carried off the ground, I sow win- Winter pease.
ter pease immediately on the stubble, covering them in with
one single plowing and harrowing. This crop has never
failed me: it is eaHier than that of corn, and nearly at the
same time with winter barley.

When the pease are carried I plow and dung the ground. Rye.
and sow it with rye.

After this rye I crop the ground in the spring partly with Mixed crop. .
potatoes, partly with other roots, and the rest with vetches
mixed with oats, to be cut as soon as the seed has formed,
and employed as pasture. All these crops are previously
well manured.

When the ground is cleared of these, I manure it tvell. Rye and clover
and begin ray rotation again with rye, on which I sow clover ^S*^"*
in the spring, as I mentioned above.

If I intended only to sow rye, I should not manure the The manure

land, after its havinej been well manured for the roots and "^cessary on

'=' , accouatoi the

pasturage, and my rye would be the fuller eared. But as clover.

the rotation of clover will leave the land three years without

dung, 1 consider this dressing as necessary. ^

I shall recapitulate my rotation of ci-ops in the following Rotation of
table. ^"^^P^-

1st year. Rye manured: clover sown on it in spring,
during dry weather, and harrowed in, without fear of injur-

ing the corn.

2d year. Clover in its most productive state. If you
would have a crop of clover seed, the second growth this
year must be left to ripen. With this view it should be
mowed the first time in May or June, when in full ilower,
»nd then left to stand for seed.
' Vol. XVIII,~-Dec. I8O7. T 3d

27^4 ^^^ ROTATION OF CROPS.

3ti yi»«*« Glorer to be mowed only twic«. The third
growth to be plowed in for raanui-e.
- 4th t/ear. Rye, or wheat, without jnanure. The wheat

Luast be hoed.

5 th 1/ear, Rye uiauui-ed.

tith year. WiQter pease, sowed on the stubble, and co-
vered by one plowing and one harrowing.

7th year. Rye manured,

Sth year. Vetches, oats, and turnips to be fed off, and
potatoes: the whole well manured.

yth year. Rye manured, on which clover is to be sown
in sprino' as before.

Obsenrations. Observations oh this rotation of crops.

Com o«cc in ^^ the first place it will be seen, that I take care to have a
ttro years. crop of com once in two years. If my clover interrupt this
course by occupying the land two 5^ears following, this is
balanced bj^ two successive crops of corn after the clover ;
the first without manure, the second with.
Croi>s charged As the land is rested by changing its produce, I do not
jj^jjjj sow clover on the same laud till after an interval of five years.

CropcTcry My land produces a crop of some kind or other every

year, with roa- ygg^j, j^j^^ j,j jj-ji,^ r^jj^jj^ years I manure it but four timee.
nure once ia i: -^ ., , i . • -c -^ ri

years. Consequently 1 have twice as many crops as it it were tal-

lowed every other year, without more expense of manure,
and I might almost say without more labour.

It is particularly to be observed, that, except after the

Pease do not clover, my land has never two successive crops of grain, un-

exlKuist the j^^g |.jjg winter pease be reckoned so, which do not exhaust

the land; and that it is so ordered, as to be cropped witli

P .. . Corn one year, and with green feed or roots the next. This

hi rejected ^* last rotation interposed between the crops of corn before the

withouvciover. ^joyp^ comes round again, appears to do away the necessity

of fallowing, without the assistance of clover, which however

I am fur from wishing to exclude by tliis observation.

ANNOTATION.
„ ' A continual succession of crops without fallowing has a

constant crop- specious appearance ot ben)g profitable at first sight ; but

as

COMPARISON OF DIFFERENT KINDS OF ALUM. Q^S

as an ihtelliij^ent friend of mine, an excellent practical far- pingeomparcd

n ■ .• X !• 11 -.1 1 ^ c c ^ with occasioi.-

mer, observes, a lair estnuate ot all the advantages ot i»i- ai fallowing.

lowing is seldom taken into the comparative calculation.
That land may be broui^ht to bear a crop of some sort or
other every year, there can be no dotibt; though it is obvi-
ous, that precisely the same manaj^ement cannot suit every
•pecies of soil. But when we compute the true value of this
practice, we should not reckon from the produce of a few
years at first, which wTll probably be higher than the average
at the long- run : at the same time we must consider, where
a proper rotation of fallows is observed, the saving of seed,
of labour in sowing, cutting, inning, threshing, and carrying
to market; and the advantage of having the land clean, and
reduced to a proper tilth by repeatedly plowing and stirring
the soil at times when the cattle and servants of the farm are
not required for more necessary labour. Thus when we take
into account the certain additional expense on the one hand,
to be deducted from the produce of two moderate or perhaps
indifferent crops; and on the other the savings in one year,
and the produce of a good crop in the next, beside the cer-
tainty of keeping the land in heart; we may perhaps be
inclined at least to doubt on which side the balance prepon-
derates, in cases where the too sanguine speak decidedly
without hesitation. At present it may be presumed no
country in Europe can be put in competition with our own
for agricultural skill; certainly France cannnot : as however
it stands foremost among the useful arts, whatever seems
likely to suggest any hint toward its promotion is not unde-
serving of notice, from whatever quarter it may come.

VI 11.

A Memoir on Roman Alum, compared ivith different Kinds
manufactured in France ; bi/ 3Iessrs, Then ard and Ro ard.
Abridged by Mr. Bouilhn'^Lagrange*.

Jl HE art of manOfacturing alum ori<rinated in the East, „« * r

^ ^ r> ' History of

and remained for a number of years the exclusive property alum works,
* Annales de Chimie, vol. LIX, p. 58. July, 1806.

T 2 ' of

sr6

Mistake of
Bergman.

Potash neces-
sary.

«

Vauquelin.

Alum a con-
stant salt,

but frequently
contaminated
with ammonia
and iron.

Preference
givfen to Ro-
man alum by
the dyers sup-
posed to be
without cause,

COMPARISON OF DIFFERENT KINDS OF ALUM.

of some cities in Syria. In the 15th century it was brought
into Europe, and soon becfime common in Ituly, where that
of Tolfa required great reputation by the constant unifor-
mity of its product, as well as its purity. But this art, slill
m its infancy, was very slowly improved; and it was not till
three hundred years after, when chemistry was sufficiently
advanced to discover the intimate nature of substances, that
it made some progress. Mar^ratf, Monnet, Erxleben, and
Bergman, then analysed all the kinds of alum most gene-
rally known. Bergman in particular was so well aware of
the importance of the question, that he wrote a dissertation
of considerable length on the history, preparation, analysis
and purification of alum ; in which he lays particular stress
on the' necessity of carefully separating the iron from it by
repeated crystallizations, by means of^which he says he ma-
nufactured alum even purer than that of Rome. He had
some erroneous ideas however, which modern chemists have
corrected.

Mr. Chaptal first perceived Bergman's mistake in pro-
posing to saturate the acidulous solutions with clay ; and the
simultaneous discoveries of Decroissilles, ChaptaV, and Van*
quelin, on the action of potash in the formation of alum,
and on the various combinations of the sulphuric acid with
alumine, left us nothing more to wish on these heads.

The knoVvledge thus acquired gave rise to several alum
works, the produce of which, though approaching that of
Tolfa, was not able to diminish the preference given it by
all manufacturers, or to lower the price it bore. The learned
awaited with impatience the solution of this important pro-
blem, when Mr. Vauquelin made known the result of his
analyses of Roman alum' compared with that of some other
kinds mo?t generally known. He showed, that the p'ropor-
tion of the constituent, principles of alum is always the
same, and that they differ only in consequence of a few par-
ticles of sulphate of ammonia and of iron, which he could
not find in any appreciable quantity in Roman alum. He
concluded his interesting analysis by saying, that, if there
w^re so much difference in alum as the dyers say, chemistry
in its present state was not able to detect the cause ; but that
it appeared to him more natural to suspect them of exagge-
ration :

•COMPARISON OF DIFFERENT KINDS OF ALUM. 277

ration; and he concluded, that any ttlum,' free from iron,
would be as good for use as the Roman. To place this be-
yond question however, it would be proper to make compa-
rative experiments with them in dyeing.

Encouraged by this some skilful manufacturers farther
improved the produce of their works, and supplied the shops
with alum, that wantM only a diiierent name and appear-
ance to rival the Roman.

But the predilection for Roman alum was soon abused; FactitJoits
and considerable quantities of the alums of Liege a"^ ""a^rforR^ ^"^
Javelle, to which all the outward appearance of that of man.
Totfa had been given, were sold. Most of the dyers and
manufacturers however, wlio at first had been imposed on
by this appearance, were induced afterward to be only so
much the more eager for the true Roman alum : for it was
much more easy to deceive tlum to convince them.

Sucli was the state of our knowledge repecting alum, Piize offered by

when the Society of Encourasjement, ever animated with a ^^^ Society of
-t • n ' • ' r. 1 Encouraae-

desire ol givmgour own manutactures a great preponderance ment.

over those of foreign countries, thought fit to oifer a prize
for the means of giving our alums all the properties of that
of Rome. The society having employed Messrs. Thenard Directed a
and Roard, to compare the Roman alum with that of French examl'^'tionJi
manufacture", in order to ascertain the difference both of of F'enL-haoSf
their nature and effects; these gentlemen, after having ac- ^"^^^^^^ '^ ^""^1
quainted the society with the results of their inquiry, sub-
mitted them to the Institute, before whom they laid the
numerous experiments they had made to solve the question.
They were very careful to, obtain the French alums in the Their prccau-
state in which they are commonly sold, and accordingly ^'°"*'
procured them themselves either from the manufacturers or
from the warehouses, taking at a venture a great variety of
cr^^stals from among considerable heapa.

It was of particular importance likewise, that they should
procure unmixed Roman alum. Accordingly they applied
to Mr. Schlumberger, their colleague, who has the care of

the warehouse at Paris on account of the proprietors, and to

\. v> ■ '
* Messrs. Thenai a and Roard say nothing of the English alum, though
it appears from Vauqudiu's paper, that the French consumers give it a'
decided preference over any made in Fri\nce. T.
. 't; ^,,,,. whom

278

COMPARISON OF DIFFERENT KINDS OF ALUM.

Plan of their
proceedings.

•♦

Alums com-
j)dred.

Analysis.

For the sul-
pliuric acid.

whom all the Roman alum is directly sent. Accordingly lie
had a great number of cask^ opened, that they mi^ht exa-
mine the external appearance, figure, and colour of the
crystals; and from each they took what they judged proper,
to make up in the whole the weight of 30 kilogrammes
[about 67lbs.] Tlie superiority of the Roman alum over all
other kinds met with in the shops being the object of the dis-
pute between the chemists and manufacturers, Messrs.
Thenard and Roard conceived, that to decide it an analysis
on a large scale alone would be insufficient ; and that it was
particularly necessary, to make numerous and very accurate
experiments with the best known colouring drugs on the
fabrics most iu use : and they conceived, that if, from the
whole of the facts, they could discover any necessary and
direct connexion between the results of the analysis and the
practical experiments, between the principles found by the
one and the effects obtained by the other, all the difficulties
would be elucidated, all doubts removed, and theory con-
joined with experience would lead them to a complete solu-
lution of the question.

The French alums subjected to their researches corapa-
rative'y with the Roman were those of Bouvier, Liege,
Javelle, and Curaudau.

Before they compared the effects of these various alums in
dyeing, their first care was to subject them to all the ana-
lytical trials already made by the chemists we have men-
tioned : thus at the same time they determined the propor-
tions of acid, alumine, potash, and water, and observed, as
Bergman, Vauquelin, and Chaptal had done before them,
the dangerous influence of iron. The experiments they
made on this subject constitute the first part of their memoir.

Part I.

Avalysis of Afums,

Exp, 1. To determine the proportions of sulphuric acid,
they dissolved in l6 litres [or wine quarts] of water 489 gr.
[15 oz.,6dr. troy] of each of the preceding alums entirely
freed from the dust that coiners the surface of some of -them*.

♦ The rosy du&t on the Roman alum yielded on analysis saturated
sulphate of alumine and ^mta&lt^ silex^ and oxide of iron.

- I»

COMPARISON OF DIFFEREXT KINDS OF Al.lJM. 279

loto the limpid solution of each, when completely dis-
solved, they poored muriate of barnes to saturation, and
even adJed a very slight excess, that they might be certain
all the sulphnric nt'id was throwii down. Each of the solu-
tions required precisely the same quantity of muriate of
barytes. The precipitates were washed in 90 quarts of
water; and wlieu that of the last washing was rendered but
very slightly turbid by nitrate of silver, as the water vised
for the purpose itself was, they were collected with the
greatest care.

After being dried, and calcined at a red heat for an hour,
the weight of the sulphate of barjtes produced was:

No, grammes.

1 , Roman alum 489-42

2, Alum of Bouvicr 45)070

3, ■ Liege 490*27

4, Javelle 490*27

5j -. Curaudau •••• 488*23

Mean of the whole • • 489*63

Messrs. Thcnanl and Roard adopted the proportion of 26
per cent of sulphuric acid in sulphate of barytes, because it
is the mean between the results of the anHi}'Sis of this sul-
phate obtained by one of them, and those found by Mr.
Berthollet after experiments made with the greatest care»

The determination of the proportion of sulphuric acid '

being the most important experiment, they attempted it a
second time with as much precision as beiore, and found no
difference between the quantities of sulphate of barytes ob-
tained by the two analyses.

Exp. 2. The equal quantities of sulphate of barytes ob- For the alu-
tained by Messrs. Thenard and Roard in the preceding tnals min^^*
leaving them no doubt with respect to th*^ projiortions of sul-
phuric acid in the alums they had examined, they did not
think it necessary to analyse any but those oi Rome, Bduvier,
and Liege, for the purpose of acertaining the proportions of
the other principles. These give us one artificial alum, and
two native alums, of which one is the most common, the
other the most esteemed. Of each of these 4S9 grammes v

well

0^30 COMPAEISON OF DIFFERENT KINDS OF ALUM.

well powdered were dissolved- by heat in 16' quarts of water,
and decomposed by equal quantities of ammonia, which was
added in very great excess. The alumine precipitated was
washed with b'O quarts of water ; and whea that of the last
washing ceased to precipitate muriate of barytes, it was col-
lected, and dried in a large silver basin. After being dried,
and kept at a red heat for an hour, it weighed:

No. gtammes.

1^ Roman alum .... 60*92

2, Alumofljouvier • 61*82

3, Liege 6l-02

Thus Messrs. Thenard and Roard found in these alums
exactly the same quantity of alumine ; for the Jrifiing differ-
ences observed between them do not amount to a gramme
[15 ~ grains], and are such as could not be avoided in such a
long series of operations.

The authors took so -much care in washing the alumine,
and not pouring off the water till the sediment was com-
pletily formed, and liad left it perfectly clear, that they can-
not fear having assigned the quantity too small. Neither can
it be too great, i»iuce, when it was dissolved in nitric acid, the
solution did not render muriate of barytes turbid: it was
completely freed from any sulphate therefore, that might have
increased its weight.

For the potash ^^P ^' '^^^ ^^ quarts of lixivium produced by washing
each of these alums were evaporated to dryness in a silver
bowl, and the products obtained were boiled several hours
with an equal weight of quicklime. The residuum was
treated four times successively with boiling water, to take up
completely every thing soluble; and these waters were'^va-
porated to dryness, the residuum dissolved in a very small
quantity of distilled water, and this repeated alternately se-
veral times, in order to separate completely the last portions
of sulphate of lirae. The solution of each of the sulphates
of potash was evaporated for the third time, and at length
heated red hot in ^ platina capsule.

The.

COMPAUISON OF DIFFEllENT KIIJDS Of ALUM. SSV

The weights of the sulphate of potash thus obtained
were :

- No. 7 gtammes.

1, Roman alum 77*05

2, Alum of Bouvier 76*80

3, Liege • 77*33

These sulphates no longer gave any sensible precipitate
with oxalate of ammonia, and rendered nitrate of silver but
very slightly turbid. They contained a little excess of alkali,
but in so small a quantity, that a few grains of sulphuric
acid were sufficient to saturate it.

Messrs. Thenard and Roard preferred treating the sulphates
with lime to employing calcination, for they had satisfied
themselves that by calcination acidulous sulphate of potash
can only be obtained, part of the alkali always flying off.

The analysis of the sulphate of potash, repeated several Constituent

times following, constantly afforded them the same results, P'^^"^^^^^^ of

r 1 • 1 ■ r sulphate o^

and showed, that a hundred parts of this salt consist of potash.

Sulphuric acid 36*4

Potash 63'6

100 '

Exp. 4. Desirous of knowing whether the alums they had Analysed foi-
analysed contained ammonia, they treated them with caustic ^"^"^o"^^*
potash, and with lime; and as they obtained none by this but none
method, they heated jhem strongly in a retort with an equal ^o^nd.
weight of powdered quicklime; but they could not thus
discover the slightest trace of it. In fact, say the}-, we
should have been surprised, if we had found any, for we
knew to a certainty, that it could not be one of the consti-
tuent parts of the artificial alums we examined; and as to
the native alums of Liege an<i Rome, as no urine is added in
their preparation, the ammonia mnst have existed in the ore,
and from this it must have been expelled by the roasting.

We m>ust not however conceal, that it is possible to find Mayexi^tin
alums with an aniinoniacal base, though they must be very *^"''^ ^^""^*
rare, for the practice of saturating the excess of acid in the
aluminous lixivia by means of urine has been very confined,

as

1852

Analysed for
iron.

Mode of esti-
mating its
quantity.

Pvoportions.

Component
parts of alura.

COMPARISON OP DIFFERENT KINDS OF ALUM.

as it has generally been supposed, that this alkali would in-
jure the beauty of dyes»

Exp, 5. The presence of iron in alums had been demon-
strated in a positive manner by several eminent chemists, who
considered them all, including the Roman, as one and the
same salt, except so far as its properties were altered by fo-
reign matters, and particularly by sulphate of iron.

To ascertain its influence, it was necei^sary to know the
quantity contained in the alum: but analysis not affording,
any means of determining it with sufficient accuracy, Messrs,
Thenard and Roard had recouse to the synthetical plan.
Accordingly they took some alum perfectly free from iron, to
the solution of which they added from t^tt t<^ tAtj P^J't of
sulphate of iron ; and then ihey compared the effect of prus-
siate of potash on each of these solutions., more or less ferru-
ginous, with that it produced in solutions of the rive kinds
of alum.

By this method they found, that the alum of Liege con-
tained at most T^otr of sulphate of iron, that of Javelle a
little less, that of Bouvier and of Curaudau riros ^^ tt'W*
and the Roman scarcely ^o-Vo*

From all these experiments it follows, that the alums of
Rome, Bouvier, Liege, Javelle, and Curaudau contain pre-
cisely the same quantities of sulphuric acid, alumine, potash,
and water, and differ only by a few thousiindth parts of sul-
phate of iron: and that a hundred parts consist of

Sulph uric acid Q6'04>

Alumine • • 12*53

Potash 10-02

Water • 51*41

, /-

100

Part IL

- Experiments with Di/cs.

r ' t After havins; given the results of their analyses in the first

r^xpcrimcnts ° '^ ''

with dyes. patr, Messrs. Thenard and Roard proceed to the second,

which includes all their experiments with dyes. As this docs

not

COMPARISON OF DIFFERENT KINDS OF ALUM. 2l83

not appear to US capable of being abridged, we shall give it
entire.

Convinced, sav they, by tlie preceding oxperiments, that All the alums
the alums of which we iiave spoken are formed of the same J.'^^lf ^ronrSie
quantities of sulphuric acid, alumine, potash, and water ; sulphate of
and that they may be considered as identical, differing ^^^^^'^
only by a thousandth part of sulphate of iron, we began with
examining, whether their action in dyes were as different as is
commonly asserted. Desirous that this part of our labours
should not be inferior in precision to the former, we endeavour-
ed to remove every cause of uncertainty that might occur ei-
ther fro^u the mixture of the colouring matters or the substance
dyed, the variations produced by the time or vessels employed
iji the application of the monlant, the unequal body of liquor,
or the ditTerence of temperature in the baths of dye. As we
w«re anxious to observe with the greatest care all the effects,
that might present themselves in the course of our experi-
ments, we performed the greater part of them ourselves, and
all the rest were executed under our inspection in our own
dyehouse.

We have not laid before the Institute the results of more
than five hundred experiments with dyes that we have made,
the greater part of which served only to point out our course,
or confirm facts we had already observed : all those we have
suppressed would have added nothing to the various proofs we
set before them.

All our researches were made at the Gobelins: we could-
not choose a dyehouse more convenient, or offering us more
advantages; for the processes there constantly carr;ying on,
to supply the demands of three imperial manufactories, ena-
bled us to make without interruption very numerous and
varied experiments, which could not have been executed
elsewhere without considerable expense. There we found
every thing we wanted, whether of vessels, dyes, or matters
to be dyed; and no where else could we have been assisted
by a more able dyer than our foreman, Mr. Blondeau,
who to great skill in colours adds very extensive practical
knowledge.

Art.

284

COMPARISON OF DIFFERENT KI^'DS OF ALlTM.

Art. I. ComparisoJi of the effect ■<: obtained in dj/cing with the
alums of Rome, Bouviert LiegCj Javelle, and Curaudau.

Comparative The materials we employed in operating with these five
w'^ol'^ilk II- ^^ums were wool, silk, thread, and cotton. Each of these
f»en, and cot- we subjected to the preliminary preparations adopted in the.
*^"* most celebrated dyeho^ises. Aware of the extensive use of

With printed Cotton for printed goods, and that Roman alum i.>. emp'ioyed
couons. exclusively for all their delicate colours, we were desirous of

making some trials, that would enable iis to decide upon this
subject. We then had recourse to Mr. Davilliers, who rea-
dily, and with the greatest politeness, made a trial of our five
alums in his manufactory. The patterns he was so obliging
as t6 send us agreed very well with our results; but as the
unequal application of the mordant might with some plausi-
bility have been objected to us, we endeavoured to obvinte
this by adopting another method, that used in dyeing piece
goods.

Mr. Berthollet, jun., who has already distinguished himself
in the science and in its application to the arts, particularly
■with respect to printed calicoes, which he has studied with
great care in the tine manufactory of Jouy, had the civility
to come and direct us in this important part of our labour,
and assist us in all the researches we made on this subject.
List of expert- Each of the experiments that compose this article was
ments. made with all the five alums.

Woollens.

Exp. 1. Weld yellow.

2. Cochineal.

3 & repeated. IMadder.

4. • • Kermes.

5. Archil.

T/iread.
6. Weld yellow.

Cotton Thread.

,7. Weld yellow.

H.* Madder.

Exp. 9. Sumach.

Calicoes.

10, - . . Weld yelKow.

11. JMadder.

12 ,.,,,. . .Sumach.
Silks.

13. ;.Weld.

14. . . .V . ,. .Crimson,

Silks xoith the acetates produced
from the fixe alums.

lo. .Weld.-

By

COMPAUISON OF DIFFERENT KINDS OF ALUM. ggj

By these experiments we find, that the five alums act ge-NNo difference
nerally in the same maoner on woollens, that they produce ^JJ ^^^^^Jj, ^ *
some (lifterencc in cotton, and that their effects differ greatly great on sUk,
on silk. But these alums contain precisely the same propor-
tions of the same principles, and differ only by t-s^o-tt of sul-
phate of iron: we are therefore obliged to conclude, that the
differences mentioned must be ascribed to this sulphate.

The following are the experiments we made to establish
this fact.

Art. II. Alums of Rome, Boutier, Liege^ Javelle, and CU"
raudau, in their common state, compared with the same alums
pur'ificd.

After having freed these five alums from all the iron that The difference*
existed in thep, we made comparative trials with them si^lplfate of ^
thus purified, and with Roman alum and the alums of French iron.
manufacture.

We first employed prussiate of potash to precipitate their
iron ; but as this method was slow and expensive, we substi-
tuted the more simple and -well-known process of dissolving
the alum rn boiling water, and washing the pulvcriform crys-
tals in cold water. In this way we obtained the complete
separation of all the sulphate of iron iVoTn our most impure
alum, which then was no longer perceptibly affected by prus^-
siate of potash, even after several days exposure to the air.
So complete a purification however is altogether unnecessary
for the purposes of the arts.

Wool.

Exp. \6. Weld yellow.

J7- Cochineal.

18. Madder.

19. '• •• ••Kermes,

Thread.
20. -....Weld.

Cotton thread.

21. Weld,

22. Madder.

Exp. 23. Sumach.

Calicoes.
2i.......Weid,

25. Madder.

26. Sumach,

Silks.

27. Weld.

28. •«.» ••Cochineal,
29. .... .. i'ustiic.

Table of ejfpf.

rinjents.

v^'nk

<g»gS COMPARISON OP DIFFERENT KI?fDS OF ALUM.

General eflFects With weld nnd cochineal, which arc colouring matters the
© He iron. j^-,ost sensible to the action of sulphate of iron, the purified
alums gave us colours more brilliant, fresh, and in a slight
degree lighter; while those with our commau alums were all
duller, and evidently of a deeper hue. This slight increase
of the inten:;ily of the colour arises solely from the small
quantity of sulphate of iron found in our common alums.
To satisfy ourselves of this, we added to our purified Liege
alum scarcely appreciable quantities of sulphate of iron,
and gradually more and more; till, by thus restoring all it
had lost in its purification, we caused it to assume the differ-
ent states of Roman alum, that of Bauvicr, Curaudau, and
Javelle, and lastly its original state of Liege alum.

AiiT. Iir. Comparison of the alums of Rome, Houvier, Liege ^
JavellCf and Curaudau, in their ordinari/ state, xcith ihe same
alums, to xchic/i ue had added increasing proportions of sul*
^ phate of iron.

Comparison of We Were convinced to demonstration, that the slight dif-
the alums with |-gj,^j^^^g produced by these several alums in dycini); were
owing to the different and scarcely calculable quantities of
sulphate of iron they Contained: but to remove completely
every doubt, that might still be entertained in this respect,
we confirmed by synthesis all the facts, that we had collected
from analysis.

The substances to bo died, woollen, linen, and cotton, were
prepared with solutions of the alums purified, of the same
alums Avith the addition oi rhuf rV^ aV> tV> o? ^'^^ i ^^ ^^^^'
phate of iron, and of sulphate of iron alone.

The silks were alumed in the same proportions with the
five different alums, and with pure alum to which from ^-^q-o
to Too- of sulphate of iron was added.

additions of
iron.

Table of expe-
riments. Exp. 30. -|

fr

ool.

Lxp.36.^
37.

, Madder.

32. J

. . . \vpbl

38..
39.-1

• • • > 1 CKI,

.

33. -^

40.

Kermes.

34.

t • •

• ••Cochineal.

41..

35.-

42..

• Prussiate of potash.
Exp.

COMPARISON OF DIFfc'ERENX KINDS OF ALUM.

a%7

7'hrcad.
Exp. 43. Weld.

Cotton. *

44-. Weld.

4.5...'-... Madder,
4:6, Sumach,

Calicoes.
4.7..... V.Weld.

48.' Madder.

49. ••••• 'Sumach.

Exp. 50.

51. <

Silks,
...Weld.
• >» 'Cochineal.
• . . Fustic.

Silks.

53.- Weld.

54,. . . . ..Cochineal.

55. Fustic.

55. Weld.

57. • ••• ..Cochineal.

From these experiments it appears, that weld yellows are General ef. -
greened and deadened by sulphate of iron. That cochineal f^*^"*
is turned violet by it, without being altered so quickly as
kcrhies, or even as madder: and that^ without being made
dull its colour is sulllciently heightened for persons not much
used in comparing colours to prefer generally on wool those
produced by Roman alum with ^V ^^ sulphate of iron to those
of the pure Roman alum.

In the colours 011 cotton, whether sumach or weld yellow, Oa cottoo.
or madder red, notwithstanding the slight differences from the
drying of the mordant, experiments 44, 45, and 46, with
purified Liege alum and xiu- ^^ sulphate of iron, never af-
forded us deeper or duller colours than the same experiments
with Roman alum and tIo of sulphate of iron.

Sulphate of iron acts in a more striking manner on silfcs, On silk.
fcr tli£ wc\d yellows and cochineal cririsons on them were
more affected by -j-o u <^f sulphate of iron, than on woollens

Knowing the great sensibility of silk in manifesting the The quantity
smallest quantities of iron, we employed it to satisfy ourselves by^sllk*^*^*^
whether our alums did not contain abo^ve tttW part, as we
had found synthetically by pouring prussiate of potash into
solutions of pure alum, afterward altered by greater or
smaller quantities of sulphate of iron.

We alunied silks with alum freed from iron, Roman alum,
the alums of liouvier, Liege, Javelle, and- Curaudau, ai)d
similar quantities of pure alum, to which we had addocj
irom T-yVij- to -^^ of sulphate oi iron.

AftCF

Sigg C0MPARIS6T^ OF DIFFfiRENT KINDS OF ALUM.

After they were dyed,' we found in the series of tints ex-
. peiiments 56 aiid 57> produced by our pare alum rendered
more or less ferruginous, colours perfectly similar to those
of our ordinary alums. Thus ^^V^ part of sulphate of iron
added to this pure alum, afforded us with weld and cochineal
, the same colours as Roman alum ; -■^'^tt the same as the
alums of Bouvier and Curaudau; ttVit ^^^ same as that of
Javelle; and tAtt the same as that of Liege.
J he different We can no longer therefore ascribe the differences we ob-
ow^ncto 1^"^ *^^"^^ ^^ clyeing with different alums to. any other cause,
than these infinitely small quantities of sulphate of iron ;
since, by adding this substance, we converted purified and
Roman alum into alums, which gave us the same results
with reagents as the most impure kinds of the shops; and.
On the contrary, by abstracting the sulphate of iron, we could
make at pleasure, from the most impure kinds, alums pro-
ducing as fine or finer colours than those obtained with
Roman alum.

Art. IV. Experiments on the injiuence of sulphate of ammo^
nia, and of alum with an nmmoniacal base.

Experiments Many distinguished chemists have asserted on the autho-
with sulphate ^^^ ^^ Ber^rman, that alums with an ammoniacal base are
«>t ammonia. ... . . . rn • i i i • • •

mjurious m dyemg. 1 o ascertam whether this opinion were

well founded, we treated wool and silk with several propor-
tions of sulphate of ammonia, which we added to Roman
alum, and with alum without potash, having its base entirely
of alumine and ammonia,
it produced no _».^ and j^y of sulphate of ammonia produced no percep-
fcjtec , tible change in silk or wool with weld or cochineal colours,

unless in consi- ^i^.^ „>_., x, and V of this salt produced a regular degrada-
Vtv^ ^ quan- ^-Qj^^ -j^ which the colour with Roman alum and -y its weight
of sulphate of ammonia was two or three shades weaker than
t^iat with Roman alum alone.
Common Hence we had reason to expect evident changes from alum

alums not in- with an ammoniacal base, but we found no difference in its
iured by this. ^^^^^ ^^^ ^^,^^ ^^ Roman alum.

Wool

tOMPAnrSON OF nrFFERENT KINDS OF ALUM.

289

Wool loith sulphate of ammonia.

Exp. 59 Weld.

59. .. . . .Cocliiaeal.

Silk with aliun having an ammo-
iiiacal base,

Exo. 60 Weld.

Such are the facts we were dcs'iroiis of laying before the General dqK
Institute, relative to the long' undecided question of the au- ^"cuons,
periority of Roman over all other alums. They afford us
an exact and complete coincidence between the results of
our analyses and of our experiments with dyes : they show
us, that much too extensive an action has been ascribed to
the sulphiite of iron, the wholfe of the influence of which
we have pointed out, at the snine time marking its limits:
and in particular they pvove, that the opinion of the evclu-«
sive advantages of Roman alum, formerly perlsaps sufficient-
ly just, is now to be considered as an errour successfully
combated by theory, and demonstrated by experiment.
These facts lead us directly to the following consequences.

1. All alums contain precisely the same proportions of sul- Alum Itself
phuric acid, alumine, potash, and water; though they pro- ^^®"^^'^^^-
duce sensible differences with reagents, and in their applica-
tion to the art of dyeing.

'•1. These diiferences arise solely from the unequal quanti- D'ffers from
ties of sulphate of iron found in them, amounting merely to beuig conta-
a few thousandth parts, for they disappear completely on ir^^'^
the purification of the alums, and are reproduced with the
same intensity, if we. refetore to them as much sulphate of
iron as had been abstracted.

3. The Roman alum contains the least sulphate of iron : Roman alum
the alums of Bouvier and Curaudau aflbrd us a little more, f'-'^t^rom it^
but the quantity they contain is appreciable oidy by reagents,

and on silk in weld and cochineal colours. In the alums of
Javelle and Liege prussiate of potash immediately indicates
the presence of sulphate of iron.

4. Roman alum does not merit the exclusive preference Other alum
given it over other alums, for we have oUtained on wool, ™'*y ^^ {"^de
cotton, and silk, with Liege alum purified by uieans of wa-
ter, and even with the alums of Bouvier and Curaudau, us
fine and brilliant colours as those produced by Roman alum :
and if the latter appeared to us to have tlie advantage over

Vol, XVTII— Dec. I8O7. U the

Qquul to it.

£90 COMPARISON OF DIFFERENT KINDS OF ,AL13M.

the aliiras of Bonvier and Cu:-audau, we can afiBrm, that the

differences were very trifling, and onlv to be perceived by an

expene^iced eye.
i-oW part of 5. The alum of Javelle, and that of Lie<>e in particular,
Loix luTurioixs. though not containing above a ihousaiKlth part of sulphate

of iron, almost always produce duller and lesa brig;ht colours

than those with purified or pure alums.

Its effect great- ^. The effect of sulphate of iron is not the same on all
est on silk, s . ^ i -,.1 n i • ^^ • •

. substances, and with all colounnj^ matters: it is very evi-
dent on silk ^vith \*eld and cochineal colours: it is a little
least on wool, less so on cotton, and it is much less on wool, with the same
substances. Wool appears to fix a less quantity of sulphate
of iron than cotton, atid particularly than silk ; for the co-
lours oil wool are less altered by ^V o^ t^'s sulphate than on
Little with silk by T^^i ^^^ ^^ all madder, archil, and kermes coloui*s,
*" kern*^'^'^^''' very large pro^wrtions of this substance are necessary to alter

the shade, or^even to diminish its liveliness.
Every manu- ?• Every manufacturer of alum therefore, if he will, may

facuirer "^^^7 ^bansre his most impure alum, by siuiple and not expensive
makeahimof '' . .......

the best qua- means, Hito an alum, that lu its application in all the aits,

^'^y- to the most lively colours, and to substances the most sen-

sible to the influence of sulphate of iron, shall possess all
the properties of the long: boasted Roman alum.
Remarks on Let US hope, that the importation of foreign alum into

the French France, which amounted a few years ago to several millions
of livres, and which has already decreased in a considerable
degree, will soon cease entirely : that our alum manufactu-
rers, better acquainted with their real interest, will no longer
endeavour to distinguish their good.s by' that coloured coat-
ing, which has most frequently been the resource of fraud :
that their endeavours to furnish the shops with an alum con-
stantly pure will soon lead all our manufacturers to think no
more of Roman alum : and that ultimately our alum works,
obtaining deserved celebrity, will be greatly increased, ex-
tend their sale to foreign countries, and enrich France with
a consideijable branch of trade.

IX.

ON THE IMPROVEMENT OF POTTERY. , ^91

IX.

Essays on the. Improvement of Pottery in general, or the Art
of making, at the least Expense, Vessels for every Use,
tnore handsome, strong, and wholesome, without employing
Lead or Tin, in the Composition of the Coating, Enamel,
or Glaze: by Mr. C. R. Jousselin, Manufacturer at

, Nevers, An Abstract by Mr, GvYTO]<i*. \

JLN the pamphlet that has just appeared under this title, History of the
the author, after noticing- the importance of this branch of ^"^ '
industry, takes a rapid view of the periods when the porce-
lains of Japan and China arrived in Europe, the introduc-
tion of Delft ware into France, which dates no farther back
than the 15th century, the extensions of the art which have
long rendered it an advantageous branch of foreign trade,
the importation of the white English ware, and manufacto-
ries established to imitate it.

He next lays it down as an estaljlished principle, at least No good pot-

amone men of science or those acquainted with the art, that ^'^"'^ butstone-
, V , , , 11- ware and por-

there is no truly good pottery but stoneware and porcelam : cdain.

as they are the only kinds, in which strength, neatness, and

wholesomeness are combined.

Before proceeding to the proofs of this, Mr. Jousselin importance of
justly observes, that this principle is not only interesting to the art to
the progress of the art; but that it merits the greatest at-
tention in a political and commercial view, particularly as
the neglecting it must render the French tributary to foreign
nations, and this to no small amount, were it merely for the
lead and tin employed in the composition of the coatings.

Common pottery, intended to stand the fire, has a very r^j^rnon pot-
porous biscuit, which is but slightly baked, that it may be tery f >r culi-
oapable of sustaining the transition from heat to cold, and '^*'"y "'^^^'
because it is not refractory enough to support a greater heat.
For the same reason it can only have a very fusible covering.
This is commonly sulphuret of lead, and oxides of copper, . ,
iron, and manganese.

^ • Annales de Chimie, Vol. LXII, p. 213, Mai, 1807.

U 2 Delft

2£^^ ON tChe improvement of pottert.

Delft. Delft ware, which was a grand invention in its time, on

account of the beauty of its coating, has likewise the defect
of being baked only so far as to vitrify the enamel, as a de-
gree of heat beyond tliis would spoil it. This renders it ne-
cessary, to employ a sufficient quantity of lime in it, to give
it a little consistency by a conamencement of fusion*

Its defects. "^ Its coating, composed of glass of lead and silex, rendered
white and opake by oxide of tin, cannot support changes
from heat to cold, and its biscuit is liable to imbibe grease.

Queen's ware. The white or pipe ware, after the English fashion, is
lighter; its biscuit has more solidity, being composed of
purer clay, and prepared flints ; and it is previously baked :
but the coating given it is much more fusible than that of
delft ; it is a glass, incapable of enduring an equal heat; is
subject to crack; is very easily scratched, when any oily
matter will penetrate the biscuit and leave spots ; and if the
glass of lead be in excess, which is unfortunately a too com-
mon case, oils and vegetable acids attack it, and render its
use dangerous.

Its glaze defec- The memoir published by an able chemist, Mr. Proust,

tive and dan- ^^ remove any apprehension of injury from its use, induced
Mr. Gay-Lussac and myself, to pay great attention to this
subject, at the time of the last exhibition of the products of
French Industry. We found very little, that was capable
of completely resisting the edge of a knife ; and after this
it could not stand the test even of boiling acetic acid, or the
yolk of egg boiled hard. We cannot therefore avoid adopt-
ing the opinion of Mr. Jousselin, that, whatever attempts
be made to improve this manufacture, it can never form
good pottery.

Is stone-ware Hence then it may be admitted as a general principle,

capable of be- ^^^^^ ^^^j ^.^^^^ kinds are admissible, stone-ware and porce-

ing made a *^ . ., ,

substitute for lain. But is it possible, to answer every purpose of strength,

every thing but gjggj^,^(,g^ wholesomeness, and economy, in a word, to ren-
der stone-ware capable of supplying the place of common
earthen-ware, or such as is required to stand the tire, of
delft, ixnd of pipe-ivare ? Mr. Jousselin affirms, that he is

Tes. convinced it is by numerous experiments. As he is esta-

blishing a manufactorj% it is natural for him to keep secret

th(e

ON-THE IMi»ROVEMENT OF POTTERY, 2^3

the processes he has tiiscovered, tliough what he says ap-
pears sufficient, to give him a claim to our contidence.

Without attempting to divine his secret, 1 shall add in stone-ware
support of its possibility, that it might reasonably have been "^^y ^^^ made
questioned, when the art wiis but a traditional practice, and fire.
when ail our stone-ware was of a close texture, incapable of
supporting the fire witliout cracking: it might have beeti'
questioned before the expevimeuts of Lauraguais in 1762, Lauraguais.
whence Mr. Jousselin dates the first conception of a com-
mon porcelain, and whose successes did not meet the en-
couragement thev deserved: before the property of magne-Useof magne-
• i . . 1 ^1 f • • ? . • X- 1 siaawdbarytes.

sia to put a stop to the fusion without impartmg any colour-
ing principle, and that of barytes to supply the place of
saline fluxes, were known: before the analyses of feldtspar Artificial feldt-
had taught us to compose it artificially with very common ^^^^'
materials: before the property of pumice stone to afford a Pumice stone
covering not attacked by any menstruum was discovered ; ^^^S^^^®*
and before the inventor of this process, Fourmi, crowned
by the Institute in the year 12, had fabricated his ht/gio- Ilygiociramcs,
ccrames, a species of common porcelain capable of standing
the fire: before the effects of heat prolonged to devitrifica- Devitrification
tion had been observed : and before the productions of the ^^ ^^^^'
manufactories of Utschneider, Lambert, and Mittenhof,
had been seen, which the jury of the exhibition of I8O6
recognized as a true stone-ware capable of standing the fire,
that is to say common porcelain*.

Thus

* I have here pointed out only the principal facts. 1 might quote
many others, that tend nit less powerfully to confirm the opinion For
instance, the spuma maris, the keffekil of Kiiwan, to which the name KefFekil,
of magnasite has been given, and of which the Turks make their pipes,
contains according to Klaproth but 0 50 silex, and 0 17 magnesia I
have found, that it loses 023 of its weight in the fire. It has the pro- its use.
perty of stopping both the vitrification and the contraction of the com-
positions ill 10 which it enters.

Mr. Giobert has shown, in the Memoirs of the Academy of Turin Magnesian
for 1802, that the earth of Baudissero, long considered as almost pure earth,
alumine, and used with success m the porcelain manufactory of Viuovo,
is a magnesian earth, containing about 0-14 of silex

Among the results of the syuihetical essays made in my laboratory at
^Jmj Imperial Polytechnic School, 1 obtained a ghis>s perfectly similar to Glass from ar-

that

294 TEST OF THE GLAZE OF POTTEKY.

Every necessa- Thus ki the present state of our knowledge it is far from
terv mav be i Impossible, that an artist perfectly acquainted witli it, and
made without improved by practice, should succeed in fabricatinfi^, as Mr.
any metal. Jousselin profejsses, three kinds of pottery, to snpply the
place, 1st, of close grained stone-ware, for containing li-
quids and other matters, with or without glazing : 2dly, of
less close grained stone-ware, with a brown glaze externally,
and a white enamel internally, for culinary utensils: and
3dly, of delfts and white earthen-wares, retaining both ele-?
gance of form and lustre of glazing, without employing any
metal.
Very cheap The enamel of which Mr. Jousselin announces the dis-

^one *^ ^^' covery is entirely earthy, and composed of materials so
cheap, that the enamel, which now costs the manufacturer
at the rate of 320 franks for a certain quantity of ware, will
come to no more than 15 or 20.

X.

Process for proving the QuaHty of a Glaze of Earthen-
War^ *.

Defects of Jl HE glaze of earthen-ware may hare several defects : it
glaze. jnay be scratched more or less readily by a hard body; weak

acids, such as vinegar, lemon-juice, verjuice, &c., may at-
tack and dissolve the lead it contains ; or oily substances
standing long on it may produce the same effect, stain it,
and render it dull.

tific'al feldt- that afforded me ' y the feldtspar of Baveno, by urging to fusion in a
spar. platina crucible a mixture of 62 parts silex, 16 alumine, 10 lime, and

Porcelain with- 12 i/otjsh. I have likewise made, without kaolin, a biscuit having the
out kaolin. hardness, semitransnarsncy, and grain of porcalain, by giving the pro-
per d-'gre3 of baking to a paste composed of 50 parts s.Iex, 20 alumine,
24Tnagne-»ia, and 6 lime I need not say, that it would be very easy to
employ the same proportions of silex and alumine, by choosing a good
clay, without being oblige^ to have recourse to the decomposition of
«lum for the earth.

• Soonini's Bibliotheque PhysicQ^6cononiique, July, 1807, p. 43.

To

GEOLOCtCAL OBSERVATFONS IN FRANtJE. 295

To (leterririfie its'po^^er of resisting friction, it raay ^ Jfiji'^g^iat^it.
nibbed with sand ; and if this scratch it more readily than
it does a glaze known to be good, we may be assured it is

soft.

If vinegar be boiled for some hours in a vessel coated with y■'nep^^^^l
• -t. » t , 11-1 *• dissolve us

a soft ghize, it will attack the glaze, and dissolve a portion jt^^d,

of its lead, which w.ll ])c precipitated from the vinegar on .,

the addition of a few drops of sulphuric acid, commonly

called oil of vitriol.

, But a method more within eveiy one*s reach, and there- '»k a ready

fore deserving to be known, is, to let fall a drop of strong

ink on a piece of earthen-ware, dry it before the fire, and

then wash it. If tbe glaze be too soft, the ink will leave oa

it a slight spot.

XL

Heights of vartovs Places in France, ^'c. ; bt/ Dr, Berger.
Continued^ from p, i217.

Sect. H.

Heights ascertained during a tour in the ci-devant Promnce of
Auvergjie,

JL HE following observations were collected in a tour made Tour in A.u-
in the spring of 1802, in company with Mr. Leopold von vergne.
Buch, a celebrated Prussian mineralogist, and Mr. A* Ju-
rine. With these gentlemen 1 set out from Geneva to visit
the chain of the mountains Dome and d'Or, traversing the
ci-devant provinces of Bugey, Bresse, Lyonnois, and Forez,
and returning through Dauphiny. As all this country, par-
ticularly the most interesting, which is for the greater part
included in the circle forming the department of Puy-de-
,Porae, has been carefully exaiuiued by several able mine-
'i»logists, I shall say little respecting its physical constita-
tion. Most of the heights were calculated by Mr. von Buch
from the simple formula of tlie difference of the logarithms
of the numt)ers expressmg the heights of the barometers at
' • , the

52P6

GEOLOGICAL OBSERVATIONS IN FRANCE.

From Geneva
along the
course of the
Rhone.

Lakes Syant
andNantaa.

Extremity of
the Jura.

the two stations* : neither were they made witli such strict
attention to accuracy, as to be considered as absolutely de-
termined.

It wouhl be diflficiilt to add any thinji^ to what Mr. von
Saussure says of the road from Geneva to Lyons in his Tours
to the Alps: I shall only* enlarge a little more than he has
done on some places where pebbles or blocks of primitive
rocks occur. Following more or less closely the course of
the Rhone from Geneva, we meet with some at the villages
of Coniigoon and petite Grave, where they rest on a bed of
soft gritstone; at Chancy, where we found on the banks of
the Rhone a granite with' reddish feldtspar ; and in the bed
of the Loudon, a small river that comes from mount Jura,
and falls into the Rhone, where there are several pebbles of
serpentine, including^ tolerably large garnets. But in a
marshy bottom situate below the village of Fougny a large
quantity of primitive compound rocks are seen^ some with
a base of diallage [sraarag'dite of Saussure] and jade, others
of almost pure jade, or compact petrosilex. Not far from
the loss of the Rhone, near the village of Vanchy, primi-
tive pebbles are still perceptible; afterward toward Chatil-
lon they become more rare ; yet I have seen blocks of gneiss
on this road, about a mile from the little lake of Syant or
Sylant, which no doubt formerly made but one with that of
Nantua, about 120 yards below it. Every thing leads us
to believe, as Mr. Saussnre remarks, that the latter ex-
tended much farther to the south-west, covering the large
flat meadows observed in that quarter, the soil of which
is composed of rounded pebbles for tlie inoit part calca-
reous.

From this place to the extremity of the Jura, between
Poncin and Pont-d'Ain, scarcely any primitive pebbles oc-
cur. There we begin to meet with pebbles of quartz in
considerable quantity, and some blocks of gneiss in the en-

♦ "Though the correction for temperature, with respect to the dilation
-of the air, is indispensable in nieasunr.g differences o( level in the same
cpuntry and at the same time j it is not quite certain, that it ought to bs
emj)loyed when we comt>are countries very distant from each other, and
take the mean of a great number of observalions." J. B. Biot's Phy-
sical Astronomy, vol. 1, p. 145,

virons

GEOLOGICAL OBSERVATIONS IN FRANCE. £9l7

Virons of Priay; wlience the road to Lyons is over plains Road to Lyons*
covered with pebbles,, frequently in such quantity as to pre-
vent the bind from b,eing cultivated. The prevailing species
are quartz, and hard quartzose gritstone. The pebbles of
the Alps indeed frequently occur, as micaceous s hist, schis-
l^se Korn.blende, and serpentines: yet when We traverse the
bed of any torrent or river coming from the adjacent moun-
tains, the calcareous stones always predominate.

Between lake Sylant and Ghatillon, about two or three
miles from this town, on the left bank of the little river is
a tolerably fine spring, called Entrebilliet, the temperature Heat of
of which on the 1st of April was 7*5° of Deluc [49° F.], ''P'-^'^S^'
while that of the open air was 6-5° [467^]. The height of
the place above the sea, as found by the barometer, was 241
toises. At Varambon, near Pont-ci'Ain, a spring rose out
of the ground, the temperature of which was 9° [5ii*25°],
and that of . the open air 12° [59°]- The height of this agreeing with
place was about 1 40 toises. These two observations agree ^^"^^^'^^''*^^'
sufficiently with the law established empirically by Mr.
Saussure, that the heat of the air decreases about l°of Deluc
for every hundred toises in height.

From Ghatillon to Nantua we found a prodigious quan- Box. -
tity of box. All the country, except the summits of the '

mountains, which are crowned with firs, is covered with
this shrub ; and from the warmth of its local aspect, it
grows to a considerable size, as in Campania and the East.

From the environs of the loss of the Rhone we do not Vines,
meet with any vines in the road, till we reach Cerdon*. At
this place is a plantation, reaching from the top of the moun-
tain, which is 403 feet higher than the lake of Geneva, to
the bottom of the declivity on the high road, which is 192
feet lower than the lake.

if in proceeding from Lyons into Auvergne we travel di-
rectly westward, traversing the Lyonnois and Forez, we are
constantly on the primitive soil. The chief base of the Granitic coun*
countiy of Limagnej that fine part of France, is well known ^'

•- The extent to which Mr. Arthur Young has availed himself of his
accurate ob.servations on the locality of certain cultivated plants, among
which is the vine, is well known. 1 do not hesitate to pursue his views
of vegetable physics, when opportunity offers,

to

g^5 GEOLOGICAL OBSERVATIONS I\ FRANCK.

to be granitic : the same kind of soil too, that we meet with
in going down the Rhone from Lyons by the way of Vieinld
and Tonrnon, occurs when we proceed to Beaujolois by
way of Tarare, Thizi, and la Claire : thus from the consi-
derable extent ocx^upied by this kind of soil in these coun-
tries the centre of all these chains cannot be far distant, and
it is not without reason, that Mr. Delametherie places it in

TheCevennes. the Cevennes, which he considers as one of the principal
centres of the primitive mountains of France.

M«untain of rjy^^ ^,^^^ ^j^^^ composes the mountain of St. Bonnet-le-

S». Bonnet. . . ^ .

Froid is an undulated reddish gneiss, evidently strutitied,

and intersected by strata or ve.ns of other rocks, particularly

white quartz, and schistose hornblende, which assumes a

porphyritic appearance mi the back of the mountaiiv to the

West, particularly between the villages of Conrsieux and

Ste Foy-l' Argentic re. Throughout the whole district of the

latter, situate in a valley watei-ed by the little river Bre-

Coat. venne, pitcoal is found. Among the fruit-trees surrounding

Chesnuts* the houses a few chesiiuts are to be seen, but all of them

. poor and low : probably thistree will not thrive without sheU

ter.

Vines and -waU On the back of the mountain of St. Bonnet, toward

nutsc ligema . (;;p^^g;gQj^_^ these are some tine plantations of vines; and in

the bottom of the valley very line walnut trees. This, is not

the only place where [ have observed the vine and the walnut

thriving- together ; probably therefore they require nearly a

similar temperature.

Holly The holly is common among the firs in the mountains of

till the Lyonuois, "und sometimes appears as a tree ten or eleven

and smooth ^^^^ high. In these cases the upper leaves are smooth, while

leaved at top., the lower ones are prickly as usual.

Lake diminish- The plain of Forez is covered with a multitude of ponds,

e<Uo i>oads. ^^^^ ^^ doubt formerly was one extensive lake. In it there

Basaltic moun- is a basaltic mount/m. The level of this plain is 185 feet

lain. below that of Limagne. Its soil is evidently formed by the

decomposition of the primitive rocks; but it appears per-

Wood sorrel, fectly adapted to wheat. One weed only infests all the fields,

the wood sorrel; but this is in great abundance, particularly

ou the i'aliows : hov/ever it is betieficial to the sheep folded

on

CE0L0G1CAL»0BSEIIVATI0NS IN FRANCE. 299

on them, for they prefer it to any other plant, whence Ta- Sheep fond of
bernaemontanus called it pxalis ovina.

In. the jrj.ej^hbourhood of Feurs I saw furze for the first Furze,
time on my road, a plant not to be met with in any part of
Switzerland.

Tahle of heights above the sea in toises and thousandth parts. Table of

heights aboTC
Without Accord- Accord- As . the level of the
cor. for ing to ing to given jea.

Places. tempera- Deluc. Trem- by ,

ture. bley. Deluc.

Chataillon de Michaille 286*068 287*945 264

Lake Syant 302-582 304-843

Cerdon •• • 191'820 193-874 158

Mexinieux 131080 132'634 118

Lyons 89*680 88

By Saussure 84 or 80
Petit-St.-Jean 121-500

The highest part of the

road over St. Bonnet-

le-Froid 390-500

Coursieux 188-000

Ste Foy-l'Argentiere ••229-500
St. Martin de I'Estra • • 297*000

Feurs • 173-000

St. Germain-le-Val . . . • 210*000
St. Just-en-Chevalet • • 352-636
The highest point of the

chain of Thiers, taken

on the road, near Ar-

consat ^ 481*601 488*096

Boen • 200-000

Noire-Table 344-500

Thiers, at the lower part

of the town 192*000

Clermont 200-000

Summit of the Pradelle,

an ancient basaltic pro- .,

montory, restiiig on

granite, but separated

from ir by a thin stra-

tu m of bolar earth .... 352*500

Orginet

300 GEOLOGICAL OBSERVATIONS J.N FRANCE.

Without cor.
for temi)erature.
Table of Orgines* 393-000

heights above The summit of Puy-de-UAmef 751-657

the level of the ^ r t^ . , , „ . fj^^ot

gea^ Jt^uy-de^lr'arion, on the edge of the crater GlO'833

at the bottom of the crater :J: • • • • 574-166

Puy-de-Barme 561-166

Orcival 448-000

Mount Jiughat, on the edge of the crater 574*166

; at the bottom of the crater 552 500

Issue of the current of lava from Puy-de-la-Vache 50y 000

Hake Aidat ........ > .;..... 419-000

MouiitUins of Croix-Marand 6.93^166

Village of Mont-d'Or-les-Bains. ................ 523-333

Cascade of la Dogne,' at bottom 654-000

— at the top § 694-333

Rock of the Cousiijs|l , . . . 8P>5-33t>'

Mountain of Cacadogneil ^)0l'Q6(i

Summit

Lava. * Here is found the grand stream of lava from Puy de-Pariou, This

lava is very fragile, and contains' only sniall crystals of feldtspar, which
retain their native hstrt,

^oii>hyry. -f This mountain is formed of a sort of porphyry, the cement of which,

not very hard, and of an earthy {^r»y colour,- includes mica and a great
many large crystals of feldtspar, which are- cracked and have a vitreous
appearance; while those found in the granite, that constitutes the base
of these mountains, have a pearly gloss.

According to Perrier the height of this, mountain above the sea is 700
toises j accoRling to Cassini and le Monnier, 757.

Crater. % 1 '^'^ crater, which is perfectly circular, measures 200 paces round :

it is covered with graSs, and cattle feed in it.

Volcanic pro- § ^" ^^^^ cxcur^ion fine feldtspars are found, in large double crystals,

ductions. in a porphyry, which according to Mr.' von Bueh cannot liave a very dif-

ferent origin from that of Puy-de-D6me. He adds, that it is a volcanic
production, but not lava. ■ . .

II If we proceed along the ridge of the inQuntain from the top of the
cascade of la Dogne, says Mr. von Buch, we arrive at the rock of the
Cousins, where we see substances that have much more ai)pearance of

Basaltes. basaltes, and in which the feldtspar becomes more rare. Continuing

along the ridge iov*ard Cacadogne, we go round's frightful, semicircular
precipice, the sides of which are covered with scoria;. This is the only

P J) lace in the neighbourhood, that can be termed a crater. From Caca-

dogne the ascent to the summit of Mont-d'Or is easy. It is an immcHSG

circus.

GEOLOGICAL OBSERVA'nO^'S IN FRANCE. 301

Without c<sr.
for temperature.

Summit of Mont d'Or* • 958-500 Table of

Circus at the footT3f Mont d'Or, before the June- SevcUflh?

tion of the waters of the d'Or and the Dogne • • GiroOO sea.

Summit of Mount Cupuein f 709*500

La-Tour-d'Auvergne+ • • 472-833

Murat-le-Qnayre, at the chateau 539*000

Rocks on the Dordogne, about half a mile lower § 417-6G6

St. Laurent-des-Mures • 117*000

Bourgoin 173*200

La-Tour-du-Pin 158*200

Pont-de-Beauvoisin 1 18*000

The lake of Epin or Aiguibellette • 193*334

Mount de I'Epin 463 666

Sect. III.

Brief description of several mount ains in the department o/" Mountains
^t T > 1 near the lake

the Leman lake. ' of Geneva.

Mount Salhe, four miles east of Geneva, is narrow, but Sal^ve.
of considerable length froiii N. N. E. to S. S. W. On the
W. N. W. it exhibits naked and steep rocks, in nearly hori-

circus, truly alpine, terminated on one hand by the sides of the valley of
la Cour, and on the other by the rock of the Cousins. These answer to
each other, and formerly closed the circus on the side of the valley of
Bains. But the whole of this vast circus cannot be a crater. I conceive,
continues Mr. von Buch, that there are two, the valley of la Cour, and Formerly two*
the funnelshaped hollow between Cacadogiie and the rock of the Cou-
sins; the remamder of the cavity was formed by the falling in of the
parts between these two craters, as is shown by the bare and salient an-
gles below the summit of Mont d'Or, and the valley of Enfer.

* According to Cassini the height of this mountain above the sea is
Y048 toises : and he afterward calculated by the barometer its height ^

'above the village of les Bains to be 512 toises, while according to our
observations it is only 435.

' \ Cassini makes this 224 toises higher than les Bains, and 760 above
'the level of the sea.
., X ^ causeway of basaltes in prisms of six feet diameter, with deci- Basaltes evi-

sive appearances of having been oritjinally a stream of lava, is seen here. "^, v "om a
■ \. J^ , ^ J i volcano.

Von Buck.

§ In this place is a grand colonnade of basaltes resembling the pipes Colonnade of

of an organ. it. ^

zontal

gQ3 CEOLOOICAL OBSERVATIONS IN^ FRANCE.

zontal strata. On the E. N. E., toward the valley of Boraes,
or the Alps, which lie beyond it, the strata decline with a
gentle and almost uniform slope. On this side we find strata
of soft sandstone imposed on calcareous strata inclining un-
der an an^le of 45°. Similar strata are found on the little
Saleve, sloping- in tlie same manner to the east. The sand-
stone^strata extend to some distance from the foot of Saleve,
joining underground those of the hill of Essery, and still
fetaining the same direction. The brook Viezou has hol-
lowed itself out a very deep hed in this soft standstone. The
Arve too has made its way across it : and in the little Sa-
leve we see beneath it strata of calcareous breccia, cover-
ing those of compact limestone tiiat form the body of the
mountain. The sides of the mountain toward the village of
Croisette are woodj^, and on the top the vegetable mould
Covers a considerable bed of white sand. In the interior of
the calcareous strata are petrified marine bodies in great va-
riety, some indications of coal, several nuclei of silex or pe-
trosilex of a naturally round form, iron in the state of earthy
oxide, &c.
^Voifoas. Mount Vuirons, three miles farther from the Leraan lake

than Saleve, would be in some measure parallel with it, if
it did not incline more to the south. Its summit forms a
long ridge. Ou the side next the lake its slope is gentle for
about two thirds of its height, where there is a small plain ;
and thence it becomes very steep, and is covered with firs*
it is comyjosed "chiefly of a calcareous gritstone, the nature
of which however varies greatly ; for the southern part of
its ridge is a kind of primitive puddingstoae, in which I
have found nuclei of a fine granite with red feldtspar and
black mica, the most rare, as Mr. Deluc observes, in that
part of the Alps which" approaches Geneva. Its declivity
- toward the Alps is much more steep than that of Saleve.
Near the southern extremity, about half way up the moun-
tain, is a large limestone quarry, the strata of which are
• nearly perpendicular to the horizon, lie east and west, and
include several species of marine petrifactions. Among
others Mr. Deluc found two large bufoniteS, which he co'n-
iniders »s new.

The

GEOLOGICAL OBSERVA'TIO^'S IN FRANCE. 30$

The valley d'AJnmdance, rich in fine pastures, ascends J^le of Abuu-
with an imperceptil)le slope to a defile, in wbichis placed a
cross, raarking the limits between France and the Vulais,
Thence the descent to the village of Monteiche, not far from f^ff^

the Pchone, is pretty quick. All the mountains on this road
are calcareous, generally steep toward the lake, and in seve-
nil places their strata are nearly vertical. Above the cot-
tages of Size, on the chaiil skirting this valley, good coal Coal,
has been found, and is wrought with advantage. The mouix-
tainsjiere are higher and steeper than those nearer Geneva,
becaiise they are nearer the centre of the Alps, and probably
too, as Mr. Saussure observes, because some of t])e lower
steps of the grand amphitheatre of the Alps are wanting
^ere.

^* The Mule is a long mountain, lying W. N. W. and E. S. E. Mdl«.
It is composed of compact limestone, which in some places
begins to assume the appearance of a schist by its disposi- ^

tion to split in leaves. There is some irregularity in the
situation of these rocks, yet they follow the law common to
all the exterior mountains of the chain of the Alps, their
slopes beiujg on the inner side, and their precipices on the
outer. Here Mr. Sausgure observes for the first time, that SeG(»nc!ary

tlie seeondasy mountains are so much the more irrepular niountains

,.,..'. . , , , . most irregular

and mcljnjijg- m proportjon as they approach the primary, xiear the pri^

It is from the Mole too we perceive very distinctly, that the mary.

Alps, to which all the surroundin<j: mountains are attached, General vievr
, „ , . . of the Al^s,

are composed of a great number oi chams, nearly parallel,

and separated by valleys following the same direction, which

in general, with some slight exceptions, is north-east and

south-w^est. On the Mole we iiieet with coarse calcareous

brecciae, imperfect vestiges of petrifactions, and frequently

nuclei or even veins of petrosilex included in limestone,

The valley of Taningey which opens into the great vale The valley pf

of the Arve near Bonneville, runs very evidently east ajid -^*"'"S®«

west. It is watered by the Gifre, a pretty considerable river

or torrent produced by the rfielting of the ice on Buet and

the mountains near that Glacier. Several of the calcareous j ,

• Lead ores con-

mountains in the course of j;his river include argentiferous tainmg silver.

lead-ores,^ The extremity of the valley is closed by moun- '

tains covered with eternal ice. The strata of the mountains

thsit

304 GEOLOOtCAL OBSERVATIONS I^T FRAXCE.

- "Inat surround the valley from Samoin are sin^cularly distort-

Bnder horizon- ^^ ^" several places. Ainon^ others I observed at the bot-

J^« torn of the mountain called Pointe de Sale strata bent con-

centrically on one another, so as to form a large ellipsis, and
over these horizontal strata. This is one instance of many
confirming Mr. Saussure's remark of the irregnlarity of the
strata of secondary mountains as they approach the primary^
I did not find a single block of primitive stone in this val-

Coitres. ley. At Samoin, the aspect of which is certainly the hottest

in the valley, I observed some cretins. On the left of the

Chalybeate ^^ad from Taninge, about an hour's journey before we reach

'pring. Samoin, is a chalybeate spring.

Bnson or Br^- Mount Brison, called Br/'xron by naturalists and geogra-
phers, forms with the Mole the entrance of the vale of
Arve. Jt is of compact limestone, and W. S. W. from the
Mole. Its summit toward this mountain is perpendicular
to a great depth, while its strata slope toward the Alps,
though very steep at the top. Its foot is covered with large
strata, nearly perpendicular, resting against the body ot the

Natural ice- mountain. In it there is a natural icehouse, containing ice
ouse. j^ij ^y^g ^.^^^ round, tliough it is of little depth. On the 25th

of July, 1800, the temperature of this cavern was 0° [32° F.]
while that of the open air was Q'b^ [54'5°].

Vejpf. The name of Vcrgi is given to a chain of loftier calcareous

mountains behind this. It declines to the north-east, and
rises to the south-west, without any reuiarkable and distinct

Lakes Saxon- summit. On its back are two lakes ; that of Saxonnex, or

uex and Lessy. g^^i, to the north ; and Lessy, which is larger but not so
deep, to the south. This has no apparent outlet; but be-
tween the little town of Entremont and that of petit Bor-
nand there is a pretty considerable cascade, spouting forci-
bly from a circular aperture in the middle of a rock lifty or
sixty yards below the summit of the mountain, and fed by
the lake. The limestone that forms this chain is of a dirty
gray, of a foliated texture like the schists, and in general
rising against the Alps at an angle of 31° or 33°. This is
not uniform however, for to the north-east ahove Scionzier
/Arched strata, ^^^ strata are arched, or bent double, and of a compact in-
stead of a slaty texture. All this chain, which some geo-
graphers still call ks monlagncs mauditeSy is very rich in

plants.

GEOLOGICAL OBSERVATIONS IN FRANCE. 505

plants, some of them rare. On the ground accumulated at

the foot of the Encrenaz, above lake Saxonnex, grows the

alpine poppy, remarkable for its iDeautiful milk white petals, Alpine popflP^

and its agreeable smell of vanello, particularly when the . ?

flower first opens.

On the east of this chain is the valley of 1e Reposoiry ^^5^^^^ ^® "
which on the opposite side is bounded by another calcareous
chain of very lofty mountains. A convent of Carthusians
here is an excellent station for a naturalist, who would wish
to explore the neighbouring mountains, which are in many
respects interesting. Having ascended mount Meiri to Point- ^^unt Meiri,
de-Chateau, one of the loftiest summits, the eye takes in the
whole chain of the Alps, and looks down upon the vale of
the Arve beneath. The highest point however is a little far-
ther west, and is called the mountain du Four, or de Pierre
percee, because its ridge is perforated. This mountain is
seen from every part of the Alps,, and at a distance appears
inaccessible, though it is not so. Had it been later in the
year I would have ascended it, but I was there in July.

The road from St. Martin to Servoz passes at the foot of
a chain of mountains, the base of which is composed of slate,
or a brown calcareous stone in thin leaves^ intersected by-
veins of calcareous spar or quartz. You then ascend to the
pleasing lake Chede; soon reach the fragments of a mOun- Lak^ChMe.

tain, the summit of which fell down in 1751 ; cross leNant- Fr/gments of
^T • 11'. -1 n 1 • 1 p 1 • 1 • '^ fallea moun-

JNon-; and, havmg passed a forest, the sou ot which is a tain.

yellowish tufa, reach Servoz, where we meet with a few per-
sons afflicted with the bronchocele, owing probably to its Cretins.
southern aspect, and being sheltered from the nOrth winds.

Ascending toward the point called P Aiguille de Varens, Peak of Va-
we meet with petrifactions in a transition limestone about
1200 toises above the level of the sea. It has no impressions
of, vegetables, but a large species of turbinite \yis]i and a
bivalve of which frequently nothing but the edges remain.
The real summit of the mountain is higher than this peak,
but cannot be seen from the bridge of Sallenches, being be-
hind the peak, which, as well as many others, is separated
from the mountain by a kind of circus of considerable depth.
On the summit of Varens is an extensive bed of numismal
stones, and some hundred toises below, among the mattei's
[^ Vol, XVIII.— Dec. I807. X that

rens.
Peirifections,

Jtg£ GEOLOGICAL OBSERVATIONS IN FRANC|;.

|hat have fallen from the mountain are many remarkajj^j
J(arg^ comua ammonis. I

JM^et. Mount Buet may be ascended not only from the valley

^fferentroadiof gj^t, taken by its first visitors, Messrs. Deluc ; or that
of Berard, the way chosen by Mr. Bounit, and described
by Mr. Saussure ; but by crossing mount Breven from the
priory of Chan^ouni, or from Servoz, by going up the val-
ValdofVilly. l^y of ViUy* This valley is watered by a rivulet, which
JEbrnas the precise boundary between the primary and secon-
dary rocks. Another observation to be uaade in this road Ib^
that the mountain above Servoz, which terminates the chain
of Aiguilles rouges to the south-west is in great part formed
^f a primitive micaceous gritstone ; there being only the
suipmit called Aiguilette, that is composed of a foliated
rock like that of mount Breven. In like manner at the
north-east of the chain the pass of Charlenton is formed of
a primitive gritstone, remarkable for its well defined small
quartz crystals; and is the intermediate point between the
primary rocks of the chain of Aiguilles rouges and the tran-
€rit or pud- sition limestone of the summit of Buet. This is another in-
clingstone ge- stance in support of Mr. Saussure*s remark, that bed? §€
the^pninary^" grit or puddingstone are almost always , foun^ betwefta the
and secondary last secondary and first primary strata.

ffi '^^^ valley of Cham.ouni runs S9uth-west and north-east,

inounL parallel to the chain of the Alps, and is bordered by moun-

Conttins some tains of the primary class. The col de Balme however, that

©econdary bounds it on the north-east, and mount Lacha, its termina-
Btrata.

tipa ^t the south-west, are composed of slate or calcareous

^stpnef* This valley contains other secondary rocks likewise,
a^s some fine white gypsum, about three miles south-west of
the priory, on the borders of the nant or torrent of Tacwiay ;
.jjtQj^e limestone opposite the priory, at a place called Biolsiy ;
A calcareous l^iid the isolated hill of Piget, in the bottom of the valley,
^^id stretching iiji the same direction, whicli is entirely formed
of limestone. These excepted, every thing in thp valley of
Chamouni i& of the primitive class.

Exactly above the priory, on the north-west of the va,ll(^,

ig mount Breven, the base of which is connected with the

Aiguilles roviges. Its summit is isylj^ted, and its striata are

^^t Q§ perpendicularly on ihU side, bjit slojpe gfintjy on the

... ... , o^hef

hill,

BrAveii.

GEOLOGICAL OBSEBVATIONS IN FRANCE.

idr

other toward the valley of Villy, which is parallel with this.
Its ascent tVom the priory, though steep, is practicable to
ubout two thirds of its height, through fragments of lamel- ^

lur rocks, mixed with quartz, feldtspar, and mica, in every
possible proportion, and of different degrees of hardness,
from the hardest lamellar granite to the softek micaceoo*
rock. These fragments come either from the summit or
from the flanks of the mountain. The summit in particular
is formed of a rock, that appears to belong to the class of
true granites, notwithstanding the parallel situation aHected
by the scales of mica, that form part of it. The back of
the mountaiu is composed in great measure of a veined gra-
nite, tvith lenticular crystals of quartz of various sizes, but

*ttoging in the direction of the laminae.

?■ The Aiguilles, or needles, on the south-east of the ralley Needles.
bf Chamouni, are five lofiy ])yramid9, decreasing in height
from the southernmost to the northernmost. The base that
supports them, which rises seven or eight hundred toi^ea
above the valley, is composed of lamellar rocks of different
kinds, but chietly quartzose or micaceous, arranged in very ?

regular strata, and running in the direction of the valley.
Their inclination toward the bottom of the mountains is
very little, but they gradually rise against the valley to the
top, where they are exactly vertical. The higher up the,
mountain they are, the more they approach the nature of
gtanite. The pyramids that rise above this are of granite
in mass. They are composed externally of pyramidal la-
rninse, subdivided into strata parallel to the planes of the
larainse themselves. These laminae are nearly vertical, and
do not lean against the valley, like the lower strata of the
inountain, but agninst the body of the pyramid. The heart
of the pyramids, or their interior part, appears in some places
to have no regular structure, and to be divided only by ac-
cidental clefts. These pyramids however must not be ima-
gined to stand upon the mass below, as a pillar on its bai?e :
on the contrary they must have a base of their own beneath,
on which the strata of this mass in part reist. . C

The Aiguille du Dru is of a nearly similar structure, but Aiguille da
among the fragments at its foot are blocks of primitive pe- ^^^'
trosilex, with a great deal of feldstpar, and a little mica.

X 9 The

308

Mount Jura.

I)Ale not so
high as Recu-

Reculet.

Temperature
of springs.

Agrees \»Uh
Saussure's law

Another does
not.

GEOLOGICAL OBSERVATIONS IN FRANCE.

The Jnra ig a chain of calcareous mountains 15O or 200
miles long:, by 35 or 40 broad ; running S. S. W. and N N. E,.
from the neighbourhood of Poii^iu in Eresse to Basil. Its
course therefore is nearly parallel with that of the Alp§, of
ide external chains of which it must be considered as a de*
pendance. It is not very easy to mark the Ssituation and
form of the strata of the Jura. ]\Jr. Saussure thinks, .thai-
the strata of the eastern chain, which \^,t\ie JQftiest arid the
nearest the Alps, rise leaning against the centre of the chain,
and decline on the opposite side; vvliile the strata of the lol-
lowiug chains to the west have the form of arches, or semi-
-arches, and terminate in plains, the l^ase of which consists
of horizontal Ji>eds of limestone.

The Dole, twelve miles north of Geneva, has been gee
nerally deemed the highest summit of the Jura. Accord-
ing to Mr. Deluc it is 658 toises above-the lake, a«d copse*
quently 847 above the sea. I co|isideF the Reculet, ten
miles north-west of Gerieva, as rath eF higher. It is one oi
the number of mountains in Ihe chain, that appear to con-
tradict the general for m, of, th^ strata above given; for, iri-.
stead of rising against the/centre of the chain, they present'
their cliffs to the Alps. - ., .-w.'-ii: u».' ;

In an expursjoii I made on the Re(cu.let,,the 7th of 4"-
^ust, 1802^ 1 5 J^scertaii^ed; th^ tejaiperature ofivvo; springs
at the same time with their,hei^ht .^bo\e. tl},e sea. The tem-
perature x)f one, situate above the chalet of Arderau, and
730 toises above the sea, was 48° [43° F.], while that of
the open air was 21-5° [80-3 F.]. That of the other, called
^oqverse, 815 toises above the sea, was 4° [41° F.], the
thermometer in the open air bting at 20*5° [78° F.]. These
twp. observations agree sufficiently with the law of the de-
crease of heat laid do^n by Mr., Saussure ;^ the following is
pot quite so consistent with it. Oa the 29th of August,
X^Q2, .the thermometer ip a fine spring near the village of
V^irisf at the foot of .mount Saleve, 200 toises above the
sea, stood at 8*5° [51-2^ F.], and in the open air at 13*7®
^62-8°F.].

XII.

ON dubuat's hydraulic theorem. 309

XII.

Trantformation of Mr. Dnhuafs Hydraulic Theorem, Bif
Thomas Young, M,D. F,R,S.

To Mr. NICHOLSON.
SIR,

i

N the course of some investigations respecting the mo- Dubuat's hy-
tion of the blood, and the rause of fever, I have had occa- transformed,
sion to employ the rules derved from the hydraulic experi-
ments of Dubuat ; and haviudj reduced them into a more
correct form than those which are mentioned in the second
volume of my Lectures on Natural Philosophy, p« 225, I
beg leave to make public, through the medium of your
Journal, the formula which I have obtained.

Dubuat's rule, reduced to English inches, is "^ — b,

h

and V — 153 [*/ cZ — -2) . ( — -} — ; ^ — -001)

I being the length of a pipe, d its diameter, h the height
of the reservoir, and tj the velocity in a second. Now

hA.xzznxii — M, when n is infinite, for the fluxion ''J^JL

becomes ultimately ~ ; and th6 same is very nearly true

when n is any large number: we may therefore express
the hyperbolical logarithm, taking n zr l6, in the terms
d i tV — S 4-1-,; and the whole formula may be changed into
another, which will often be more convenient, in this manner,
making c-h^\-^\yV=. 153 (v^(/ — -2) . (— ^ + ''Sl±l

— '0012.) This expression will be found as near the truth,
in all cases, as can be supposed to have been correctly as-
certained by Pubuat's experiments.

I am, SIR,

Your very obedient servant,

THOMAS YOUNG.

Wdhech Street, 22 Nqv,

XIII.

310 iriEORY or bar xavMPETS,

XIII.

Ohsercdtwns on tht Theory of Ear trumpets, with a View t»
their Improvement ; A3/J0HV Gouch, K^q,

Sir, Middfeshau\ *iOtk Nov. 1807'.

Animpro^red ^JTNE of your correspondents, who appears at pas,e 51 o£
requested. >^ur XlHth volunae, under the signature of A. B. has lately
*' addressed me in the same anonymous character on the subject

of ear ti umpets. He requests to learn my sentiments res-
pecting these instruments, and hints leading to their improv**
ment through the medium of your Journal,

•ni^subject hi- j^ believe but liltlc attention has been hitherto bestowed OQ

therto reglect-

cd by philoso- this part of acoustics, though the inquiry is intimately con-

P*^^*** nected with the ease and happiness of the partially deaf ol

all ranks and ages. This negligence in experimental philo-

phers, who have done so much for the improvement ot optics,

obi ges me to begin with a fundamental and essental point

' of my subject; for we are in uncertainty at present in what

Two theories manner an ear trumpet acts on the auditory organs. We

trumpeTpro- ^^*y Conceive the sonoriterous pulses to be collected in the

posed. cavity of the vessel, and to pass thence into the meatus au-

ditorius in a state of increased condensation.

On the other hand, we ma^ suppose, that the same pulses
strike the sides of the trumpet, and excite similar vibration*
in this metallic s..c'}, vliich imparts them to the orifice of the
The latter the- iiud it ory duct. The latur supposition is rendered plausible
ry p u I . ^^ ^ simple experiment ; if the porches of the ears be se-
curely stuffed with wet paper, you may convey the clicking of
a watch along a rod of wood or metal to the seat of bearing
by simply. touching the watch with one end of the rod, and
pressing the other against the'forehead, your teeth, or the wet
paper in your ears. The preceding fact, in conjunction with
other circumstances and arguments, induced me at first to
prefer the second theory of ear trumpets, and to conclude,
that the vibrations of the metal ccmstitute the real cause of
augmented sound rather th;in the condensation offlcnoriferou?
pulses.

After

THEORY OF EAU TRUMPETS. 3]!

After taking this view of the subject, I was inclined to M^. Nichol-

^ r t • 4 son's idea, vol,

Adopt your opinion in vol. XIIi, page 52, that an instrument xiii, page 52,

Cppsisting of a broad thin surface, furnished with a tail or exwnined,
Stem, promises to relieve partial deafness as effectually and
more conveniently than a trumpet. A number of experi-
ments, however, made for the purpose, have convinced me,
that the vibration excited in thin plates of metal, wood and
pasteboard, by sonoriferous pulses of air, cannot be condensed
in a stem attached to these substances, so as to be conveyed
with effect to the seat of hearing. My first trial was con- Not continued
ducted in the foUowing manner : a hole was made through a ^g^^^^^^* •
partition of lath and plaster, which was just large enough to
receive a rod of deal 2 feet long, and f an inch in diameter.
Some circular plates of metal were provided at the same
time, as well as thin boards and pieces of pasteboard of the
same figure, which were fixed at pleasure on the ends of the i

rod, by means of holes in their centres. This contrivance
gives the observer an opportunity of placing himself in one
room and the sonorous body in another; and this precaution
prevents all the pulses from reaching his ear, except those
that are conveyed by the rod, provided the force of the sound
be too weak to make its way through the partition itself.
The eff<»cts produced by this apparatus were the following:
when one of the circular plates properly mounted on the end,
was slightly scratched with a pin, or even with a piece of
twisted paper, the sound passed very distinctly along the deal
into the room where the observer was situated, and was
thrown off into the air from a circle of wood or metal fixed
on the rod in that apartment. The same circumstance took^
place when a watch was brought into contact wifh one of the
circles, and the observer stood near the other; but absolute
contact was found to be necessary, for the sound ceased as
oft as the watch was removed the shortest distance from the
circle.

The discovery of this fact damped the expectation which I Other experi-
had hitherto entertained of affording relief to partial deafness "»^"'s to the
by solid conductors of sound, but not to dismiss the inquiry
apparently- in a negligent manner, I procured two or three
plates of different elastic substances, furnished with slender

tails

3UI THEORY or EAR TRUMPETS.

tales of wood, with which I made an unsuccessful experiment
on the ears of a lady who labours under a considerable degree
of nervous deafness. An attempt was also made to convey
weak sounds by the same instrument to the auditory organs
through the medium of the teeth, when the ears were stopped ;
but att these trials failed, unless the sonorous body happened
to touch some part of the apparatus.

This succession of disappointments convinced me, that
solid conductors can be of no advantage to the partially deaf.
^Probable use of Instances of great insensibility may occur indeed, in which
•^lid cofaduc-^e may arrive at the seat of hearing by their assistance,
through the channel of the mouth, after every trial to ap-
proach it by the natural ducts and passages have proved
'fruitless. In this manner, perhaps, some persons apparently
in a state of absolute deafness, might acquire some idea of
the musical scale by attaching one end of a stick to a harpsi-
chord, and holding the other in the mouth. At the same
time, lam apprehensive your correspondent A. B. will be un-
fortunately disappointed in his expectations of relief from
conductors, which are to be held in the teeth in the manner
of a tobacco pipe.
Anexperiment The next experiment relates more directly to ear trumpets,
trumpet. ^"^ discovers the mode in which they operate on the auditory

organs. I took a hollow copper cone, the mouth of which
^ was finches in diameter, and having closed one of ray ears
with wet paper; I introduced the small end of the tube into
the other, taking care to cover that side of my face with a
^ 'folded handkerchief, with a view to intercept as much as

possible such vagrant pulses as were not received by the

* trumpet. Upon directing the wide end of my clumsy instru-
tnent towards a' watch on'a' table, I found that it rriagnified
the strokes of the balance beyond my expectation. But this

* was the case only while the tube remained open, for the
watch ceased to be audible after a plug of wet paper had
been forced into the narrow part of the tube, at the distance

Trumpets con- ^f ^ ^^ 3 inches frorri the smaller extremity. This experi-
Hense sonori- nflent poihts out the officfe of an ear trumpet in ii satisfactory
ferous pulses. , , • i i .111

manner. Its business is to condense the pulscsvvhich happen

' tO" fall into its cavity, and thereby to discharge them \yith
' ' ■ ■ ' greater

THEQRY PF EAR THUMPETS, gjj

greater effect into the auditory ducts; our attention therer-
fore, must be turned in future to the most probable means of
increasing the condensing power oi the instrument, if we wish
to mitigate the inconvenience of nervous deafness.

A vessel of a parabolical figure, and well polish(>d, promise^ Parabolictruift.
to be of service to the infirmity of partial deafness, on asu- Jered*^"^*'
perficial consideration of the subject, because such an in-
strument would concentrate in its focus all the pulses whiclji
happened to enter its mouth at the same instant, in a direc-
tion parallel to its axis. A trumpet of this description is
liable to two serious objections, for the construction of it is
very difficult, if not impossible; and if such a thing could
be made, it would be attended with inconveniences, arising
from its shape and ilimensions, that would render the appli-
cation of it very troublesome. This may be easily proved by
Q. few simple calculations derived from the properties of the
parabola; in reality it may be feared, that the partially deaf
have little to expect from any kind of ear trumpets, but those The itnprore-

of a conical fisuie; and apparently strong reasons lead me ments of coni-

" ' * ^ . ^ cal trumpets

to suspect the best of them to be very imperfect augmenters difficult,

of sound. Perhaps! may take a future opportunity to con-
sider their defects mathematically; Out it will be sufticient
for the present purpose to observe, that very few of the
pulses received at the mouth of a conical tube are trans-
mitted "^o the ear through the opposite extrcxiiity. This
might be demonstrated on the well known laws of incidence
and reflection, and the truth of it is experimental!, proved
by the office of the funnel in the invisible lady, which does **

not transmit the whisper committed to ic so much as it re-

■ . ■ -'♦

fleets it.

It may be here naturally asked, if the partially deaf are to Anmstrument

lay aside all future hopes of additional relief from the im- ^^'^ ^^® P""^^'
. ^ . . > T -11 ' . ' pie of a drum

provement ot acoustic instruments? 1 will not venture to give recommended.

a decisive answer to this question ; perhaps future experi-
ments may discover a more convenient and efficacious form of
the ear trumpet ttiaij any in use at present; but I would re-
commend your correspondent A. B. or some one of his fellow
sufferers, to exchange his trumpet f)r a drum, by way of
trial. Perhaps tliij> hint will appear obscure in its present

form,

914

THEOUT OF EAR TRUMPETS.

form, and an explanation will be expected. By a drum I
mean a circular box, or funnel, furnished with nn car pipe,
and having its mouth or widest aperture covered with a thin
elastic membrane, which must be stretched with an uniform
force in every direction, like the vellum of a military drum.
The pulses which fall from the atmosphere upon this mem-
brane will be immediately transmitted by it to the air con-
fined in the box, and their escape from this cavity must evi-
flently he through the" ear tube, because the covering of the
mouth will not permit them to return into the atmosphere by
that aperture.
An experi- The instrument here recommended is not a mere project of

with such an ^^^^'T? ^^^ ^ \mve made some experiments, which induce me
instrument. to hope for beneficial consequences from a contrivance of the
kiiSdV'' I tooka metal funnel of 2 inches radius, And a circu^
lal- wood box of the same diameter, which was a' segment 6f
'^ A sphere of 8 inches radius. The mouth of each vessel was
covered with apiece of hog's bladder, moistened in water,
and securely fixed by a thread to the outside of the instru-
tieiiC The bladder contracted in drying, by whicih it ac-
quired a considerable degree of tension; and I do not hesitate
to say, that both these drums, when properly applied to my
^a'r, augmented the beats of a watch and other weak sou rid «,
The further in a manner which was very perceptible. Should tHe experi-
thre'^jeT °^"l^"^ however, appear worthy of further attention, it must
jnent left to be left in future to those who expect advantage from it', Be-
^epartially cause such inquiries are attended with the greatest difficul-
ties, when undertaken by persons who possess the sense of
hearing in perfection. If your correspondent A. B. should
conclude to pursue the subject, he will recollect, that a fine
membrane is prepared from the intestines of cattle, which is
called gold beater's skin, at least in the north of England ;
and it is unnecessary to inform him, that this substance is
preferable; in every point of view to the bladder which 1 used

in my experiment.

JOHN GOUGH.

P, S. I have long expected, that some of your corrcspon-
dentb would call an opinion in question, which \ advanced

nearly

ON SPARRY IRON ORIS. 315

ntari)' two years ago in the Philosophical Journal ; but their
::>ileiice obliges me to become my own accuser. Jiome expe-
riment of mine will be found in your number for JVJarch, Water may be
1806', from which I inferred, that water cannot retain its go©
fluidity when cooled below 32°. Such was my opinion at
the time, but I was soon induced to suspect its accuracy from
a conversation on the subject with Mr. Dalton, of Manches-
ter. The gla&s vessels Ubed in my experiment:* were exter*
nally covered, witb the freezing mixture nearly to their
brims; but in consequence of this gentleman's infownation,
I repeated the same experiment last winter, care being taken
to raise the upper half of the vessel, containing the water, above
the salt and snow which surrounded its bottom. With this
precaution I found water might easily be cooled many de-
grees beiow the freezing point ; in consequence of which dis-
covery, I was obliged to abandon the theory referred to above,
and HI pronouncing it to beanerrourlamonly doing justice to
the truth and your excjrllent miscellany.

XIV.

Report made to the Mathematical and Physical Class of the
Institute, on a Memoir of Mr. Descotils, relative to Iron
Spar: hy Messrs, Berthollet, Lelietre, and Vav-

QUELIN*.

spara vary

JLN January 1806 Mr. Descotils read to the class a memoir iron

in wbich he proved by expenmer\t8, that the iron spar, which ^"^ *heir princi-

was the subject of it, varied in the proportions of its consti- be differently

tuent principles ; and hence he explained the differences treated.

that the ores require in their metallurgic treatment. The

difficulty of fusing some of them constituted at that time

the principal object of his research; and the comparative Their refracto-

analysis he made led him to the conclusion, that the mag- '■'"^ss owing to,

nesia, which is frequently found in them in large quantity,

was the cause of their refractoriness.

Reflecting on the processes adopted to deprive these ores Processes Tsy

•j^nales de Chimie, vol. LXIJ, p. 135^ May, 1807.

of

516

ON SPARRY IRON ORES.

whi h he are
deprived ot it.

Their moc^e
of operdticn.

Hassenfrata;
started some
objections, but
appears to have
Ifiven them up.

The author
has repealed
his experi-
ments, and
made fresh.

Experiment
with ore of
Elba.

Effect not ow-
ing to its being
powdered.

R«riaotoflness

of the principle of their infusibility, which consist chiefly in
exposure to the air and raiu, eitlier before or alter roasting,
Mr. Descotils conjectured, that these piocestes had no other
effect than that of separating- the magnesia.

In the lirst case, that is to say, when these ores were ex-*
posed to the air before roasting, he supposed, that this earth
was dissolved in the slate of carbonate by the rain, in the
second, on the contrary, he ascribed this ettt-ct to the sulphu-
ric acid developed by the eiflorescence of the pyrites, with
which the iron spar is aunost always accompatiied.

Since that period Mr, Descotils ht s ccumiumicatedtothis
assenably a second memoir, in which he fu.nishes substan-
tial proofs of the explanations he had oiie^ed in the lor-
mer paper as merely conjectural ; at the same time avails
himself of them to answer some objections, that had been
advanced by Mr. Has?enfratz. The latter gevjtleman how-
^ver,^ after having made some fresh experiments and obser-
vations, has withdrawn his memoir, w-hich the class had re-»
fer red to the same committee: we shall not therefore enter
into any discussion of the points, on which these two learned
chemists differed, but shall consider the facts related by Mr,
Descotils, and the conclusion he has deduced from them, as
jf they had never been disputed. *

On this second occtislon Mr. Descotils has repeated his
former experiments, which gave him the same results. He
has likewise made new ones; and all, mutually supporting
each other, have only confirmed him in his opinion. But
let us relate some of these experiments..

He exposed to the fire a mixture of fifteen parts of mag-»
nesia, and a hundred parts of iron ore from the isle of Elba,
finely powdered ; and the result he obtained was perfectly
similar to what every magnesian iron spar has furnished him.

To ascertain whether the division of the particles of the
substance had any influence on its fusibility, lie made atrial
with part of the same specimen of iron ore of Elba, without
wasting or powdering it, and he obtained a perfectly compact
button, at a degree of heat similar to what would have been
requisite for an assay of earthy iron ore with the addition of
borax.

This fact shews, snys the author, that cohesion does not

diminish

Olf SPARRY IRON ORES.

#

diminish the fusibility of iron ores; at least if this cohesion therefore not
can be estimated by the harclncss of the ore, and the resis- gjon. '
tance it offers to the action of acids, for none possess these
two qualities in a more striking degree than the iron crystals
of the isle of Elba. The committee are of a similar opinion,
only the fusion must requife so much lousier time in pro-
portion as the ore is in frag^ments of a larger bulk,

' 'Mr.'DescOtils could have wished to analyse specimens of
i^fractory iron "spar coin pari tively with specimens of th6
same ore become fusible by exposure to the air: bat not hav-
ini^been able to procure any, he thought he might supply
their place by two pieces from the same vein, one of which
was not altered, the otheir had passed to the state of a free
ore.

Without describing the method be employed for this pur- 'But tomagn*;.
pose, which we' Consider as very accurate, we shall only say, *^^'
tiiat be found the dtx!omposed ore no longer contained any
magnesia or carbonic acid, while the other contained four per
cent of carbonic acid and magnesia.

The analysis of live other specimens of free ores, from Farther proofs,
different places, gave him the same results, whence he con-
cludes, that the separation of the magnesia is complete when
the decomposition of the ores is complete.

In some cases he suspects^ that it is to the efflorescence of Modeinwhick
the pyrites, from which scarcely any spai-ry iron ore is free, the magnesia.
that the solution and abstraction of the magnesia of the raw ^^ ^^^^'^ ; ,
ore is owing; since sulphate of magnesia is sometimes to be
observed on heaps of ore of an analogous nature exposed to
the air, as well as in the waters with which these ores are
washed ; and he has obtained similar results in a small way,
by putting magnesian iron spar in powder, into a solution of
sulphate of iron.

He believes however, that it is most frequently the carbo- Action of car-
nic acid, which, disengaged from the iron in proportion as
this absorbs oxigen, dissolves and carries ofl" the magnesia by
means of watep, .1

As to the change effected in the roasted ore by exposure Effect of roa^-*
to air and rain, the conjectures of Mr, Descotils are con- ing.
firmed by analysing the waters, with which a heap of roasted
ore long exposed to the air had been washed. These waters

contained

•1«

■;2?:rs'?''s

Old ores more
fusible than
SL«vr,

Magnesia
most iiiiurious
to rich ores.

Ko external
marks of its
jprcience.

Application of
heal alone the
best test.

Marks of a re-
fractory ore.

Marks of a fu-
sible ore.

Indication of
manganese.

Loss in roast-
ing.

Quantities of

ON SPARRY inON ORES.

contained nothing but sulphate of magnesia, and a little
sulphate of lime; which suits could have been produced
only by the action of the sulphuric acid, arising from the
pyrites, on the earthy substances contained in the ore.

Mr. Descotils quotes letters of several well informed per-
sons, and worthy of credit, v/ho, in agreeing on the point
that sparry iron ores recently extracted and roasted are more
difficult of fasion, and less productive, than those that have
remained three or four years in the open air, give ftiil more
force to his theory.

Though it is certain, that the presence of magnesia in
iron ores diminishes their fusibility more or less, the author
of the memoir observes however, that, if it be accompanied
with a sufficient quantity of lime, silex, and alumine, or of
oxide of manganese, it is not so injurious, because it be-
comes fusible by combining with these substances.

Conceiving the advantage iron masters would find in hav-
iiig an easy method of knowing by simple inspection a free
from a refractory ore, Mr. Descotils has examined, whether
among the external characteristics of these substances there
might not be some, by which these properties could be dis-
tinguished : but the strictest scrutiny in this respect waS
without success. He has been obliged therefore, to have
recourse to chemical means, and what he found most to the
purpose was fusing the ore without the addition of any flwj^*

If a^te^ this operation the matter present itself in a grayish,
earth}^ friable mass, interspersed with small globules of cast
iron, it is a proof, that the ore is niagne&ian, and consequently
more or less refractory.

But on the contrary, if a well fused button be obtained,
with brown and not very abundant scoriai, the ore is fusible,
and contains but little magnesia.

When the scoriae are green, they indicate the presence of
oxide of manganese, part of which is reduced, and mixes
with the cast iron, by a high and long continued heat.

The least altered kinds of sparry ores, that Mr. Descotils
assayed, lost in roaating from 31 to 37 per cent. The altered
or free ores lost at most but 14 per cent, and this loss was-
merely water.

The quantities of magnesia and manganese vary greatly j
, sometimes

ON SPARRY IKON ORES« ^|^

•ometiraes there may be 12 per cent of either in the raw ore, manganese
and at others there is scarcely any. ^*^ magnesia.

From the results of his analyses Mr. Descotils concludes, Never a maxi-
that a high proportion of one excludes a high proportion "^^^*^^^^^'
of the other, without the absence of the one necessarily in-
dicating" the presence of the other; so that the iron, when
brought to the state of red oxide, always amounts to 60 per
cent at least.

Hence Mr. Descotils explains what takes place in the Ca- Cataloniaa
talonian forges, where the different species of ore are treated '^'^^^'
according to the nature, number, and quantity of the prin-
ciples they contain. He points out the method, that each
requires, and the product they afford, according as the ope-
ration is conducted. Sometimes it is cast steel, at others steel from th«.

malleable iron, or some mixture of the two. On this occa- ^^'-' Pyreaoau

ore.
fion he expresses his surprise, that no one has yet thought of

establishing a manufactory of cast steel in the Pyrenees.

He thinks justly, that all rich iron ores, which contain btit Richores»
few earthy parts, such as those of the island of Elba, might
t)e fused with advantage in the Catalonian method.

It follows evidently from the experiments of Mr. Descotils, General d©*
that certain kinds of sparry ores owe their infusibility to the Auction**
presence of a large quantity of magnesia: and that the prin-
cipal object of the exposure of these ores to the air and rain,
either before or after roasting, is to separate the magnesia,
and render them fusible. The various experiments we have
witnessed, and the results of which we have seen, leave us no
-doubt on this head: since on the one hand the ores in which
there is no magnesia are easy of fusion, and those which con-
tain a certain proportion are wholly infusible; while on the
other the addition of magnesia to fusible, ores divests them of
this property, and infusible ores, when their magnesia is ab-
stracted from them, become fusible.

From the observations of Mr. Descotils it farther follows,
that there is no external character, by which we can distin-
guish whether a sparry iron ore be fusible or not: but he has
pointed out chemical means of determining their nature,
which are easy to put in practice.

Hence we are of opinion, that Mr. Descotils has thrown
much liglkt on the working of sparry iron ores; and that, as

big

82d SCIENTIFIC NEWS.

his memoir may in consequence be a verj^ advantageous guide
to the iron master, both from the well conducted experiments
it exhibits, and the reflections and ideas he has added to them,
the class should direct it to be printed in the volumes of its
foreign contributions.

SCIENTIFIC NEWS.

R. Bucliolzhas analysed the seed of lycopodium, which
Analysis of has afforded him the following results. A thousand parts of
ycopo mm. ^^^ ^^^j contain ^0 of a fat oil, analogous to castor oil, and
very soluble in water, 30 of true sugar, and 15 of a mucila-
ginous extract. The remainder consists of a suh'^tance alto-
New substance g^t he p insoluble in water, alcohol, ether, oil of turpentine,
or caustic lixivium of potash. By long boiling with liquid
potash however this substance is decomposed, gives out am-
monia, and is converted into an extractive matter.

By distillation it affords carburetted hidrogen gas, and car-
bonic acid gas; and afterward a watery liquor, impregnated
with acetate of ammonia, and an empyreumatic oil. I'heie
remains a coal very analogous to anthracite, and difficult of
incineration.

Nitric acid moderately concentrated being boiled on this
substance converts it into a fat oil equally soluble in alcohol.
The author concludes, from his experiments, that this peculiar
matter must be considered as distinct from all other vegeta-
ble or animal substances.

Mr. Thenard had supposed, see our last number, p. 1^5,

that a certain quantity of water was formed in the mutual
Nowaterform ,. , i , , • i . i i •

cd in making action of alcohol and acetic acid : but he now says he is con-
acetic ether, vinced, that none is actually formed, of which he shall fur-
nish proof in his memoir on ethers.

To Correspondents,

Mr. C. Sylvester's paper was too late to be inserted in the

present nv^mber^ but will be given in the next.

A

J O U R N

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

SUPPLEMENT TO VOL, XVIIL

ARTICLE I.

On some Chemical Agencies of Electricity. Btj Humphry
' Davy, E*g. F,R,S, MALL A, Read November ^0^ .
1806 *

1. Introduction*

'A HE chemical effects produced hy electricity have been Introductoif
for some time objects of philosophical attention ; but the ^^"^'
novelty of the phenomena, their want of analogy to known
facts, and the apparent discordance of some of the results,
have involved the inquiry in much obscurity.

Art attempt to elucidate the subject will not, I hope, be
considered by the Society as unfitted to the design of the
Bakerian Lecture. I shall have to detail some minute (and
I fear tedious) experiments ; but they were absolutely es-
sential to the investigation. I shall likewise, however, be
able to offer some illustrations of appearances, which hitherto
have not been fully explained, and to point out some new
properties of one of the most powerful and general of ma-
-terial agents.

* From the Philosophical Transactions for 1807, Part I.
Voj.. XVIIL— SuppiEMSNT. Y IL

322 ^N SOME CHEMICAL AGENCIES OF BtECTEICITY,

11. On the Changes produced by Electricity in Water.
Early observa- The appearance of acid and alkaline matter in water acted
*"*d^alLr"*^ on by a current of electricity, at the opposite electrified
Voltaic experi- metallic surfaces, was observed in the first chemical experi-
ments, raents made with the column of Volta *.

Mr. Cruickshankt supposed, that the acid was the nitrous
acid, and the alkali ammonia. M. Desormes J soon after
attempted to show by experiments, that muriatic acid and
ammonia were the products, and M. Brugnatelli § asserted
the formation of a new and peculiar substance, which hehas
thought proper to call the electric acid. The experiments
said to be made in Italy, and in this country, on the pro-
duction of muriate of soda are recent j], and the discussions
with regard to them still alive. As early as 1800, I had
found that when separate portions of distilled w ater, filling
two glass tubes connected by moist bladders, or any moist
animal or vegetable substances, were submitted to the elec-
trical action of the pile of Volta by means of gold wires, a
nitre-muriatic solution of gold appeared in the tube con-
taining the positive wire, or the wire transmitting the elec-
tricity, and a solution of soda in the opposite tube **; but
I soon ascertained, that the muriatic acid owed its appear-
ance to the animal or vegetable matters employed ; for when
the same fibres of cotton were made use of in successive ex-
periments, and washed after every process in a weak solu-
tion of nitric acid, the water in the apparatus containing
' fhera, though acted on for a great length of time with a
Tery strong power, at last produced no effect upon solution
of nitrate of silver*

In cases when I had procured much sodaj the glass at its

*' Nicholson's Journal, 4to. Vol. IV, p. 183.

t Ibid. Vol. IV', p. 261.

I Annales de Chimie, Tom. XXXVII, p. 233.

§ Phil. Mag. Vol. IX, p. 181.

li ByM. Pacchioni, and by Mr. Peele. Phil. Mag. Vol. XXI,
p. 279.

** I showed the results of the experiment to Dr. Bed does at this
time; and mentioned the circumstance to Sir James Hall, Mr. Clay-
.field, aiid other friends in 1801.

-point

ON SOME CHEMICAL AGENCIES OP ELECTRICITY. 323

point of contact with the wire seemed considerably corroded ; Changes pro-
and I was confirmed in my idea of referring the production tricity ia water.
of the alkali principally to this source, by finding that no
fixed saline matter could be obtained, by electrifying distilled
water in a single agate cup from two points of platina con-
nected with the Voltaic battery. Similar conclusions with
regard to the appearance of the muriatic acid had been
formed by the Galvanic Society of Paris, by Dr. Wollaston,
who hit upon the happy expedient of connecting the tubes
together by well washed asbestus; and by M. M. Bipt and
Thenard *.

Mr. Sylvester, however, in a paper published in Mr.
Nicholson's Journal for last August, states, that though no
fixed alkali or muriatic acid appears when a single vessel is
employed ; yet that they are both formed when two vessels
are used. And to do away all objections with regard to ve-
getable substances or glass, he conducted his process in a
Tcssel made of baked tobacco-pipe clay inserted in a crucible
of platina. I have no doubt of the correctness of his results;
hut the conclusion appears objectionable. He conceives, that
he obtained fixed alkali, because the fluid after being heated
and evaporated left a matter that tinged turmeric brown,
which would have happened had it been lime, a substance
that exists in considerable quantities in all pipe-clay; and
even allowing the presence of fixed alkali, the materials em-
ployed for the manufacture of tobacco-pipes are not at all ^
such as to exclude the combinations of this substance.

I resumed the inquiry ; I procured small cylindrical cups
of agate, of the capacity of about | of a cubic inch each.
They were boiled for some hours in distilled water, and a
piece of very white and transparent amianthus, that had been
treated in the same way, was made to connect them together;
they were filled with distilled water, and exposed by means
of two platina wires to a current of electricity, from 150 pairs
of plates of copper and zinc 4 inches square, made active by
means of solution of alum. After 48 hours the process was
examined : paper tinged with litmus plunged into the tube
containing the transmitting or positive wire was immediately

■^ No. XL cfu Moniteur, 1806.

Y ^ strongly

<^g4 ^^ S&Sm eHEMtCAL AGENCIES OF SLCCTRICtTf*

Changes pro- stroncrly reddened. Paper coloured by turmeric introduced

ttid^^ in >vater *"^^* *^^® ^^^^^ *"^^ ^*^ ^** colour much deepened; the acid
matter garc a very slight degree of turbidness to solution of
nitrate of silver. The fluid that affected turmeric retained
this property after being strongly boiled ; and it appeared
more vivid as the quantity became reduced by evaporation;
carbonate of ammonia was mixed with it, and the whole dried
and exposed to a strong heat: a minute quantity of white
matter remained, which, as far as my examination could go^
had the properties of carbonate of soda. I compared it with
similar minute portions of the pure carbonates of potash and
soda. It was not so deliquescent as the former of these
bodies, and it formed a salt with nitric acid, which like ni-
trate of soda soon attracted moisture from a damp atmos-
phere, and became fluid.

This result was unexpected, but it was far from convincing
me, that the substances which I had obtained were generated.
In a similar process with glass tubes, carried on exactly under
the same circumstances, and for the same time, I obtained a,
quantity of alkali which must have been more than twenty
times greater, but no traces ef muriatic acid. There was
tncch probability, that the agate might contain some minute
• portion of saline matter, not easily detected by chemical
analysis, either in combination, or intimate adhesion in it«
|)ores. To determine this, I repeated the experiment a second,
a third, and a fourth time. In the second experiment turbid-
ness was still produced by solution of nitrate of siWer in the
tube containing the acid, but it was less distinct; in the third
process it was barely perceptible: and in the fourth the two
fluids remained perfectly clear after the mixture. The quan-
tity of alkaline matter diminished in every operation ; and in
the last process, though the battery had been kept in great
activity for three days, the fluid possessed in a very slight
degree only the power of acting on paper tinged with tur-
meric; but its alkaline property was very sensible to litmus
paper slightly reddened, which is a much more delicate test:
and after evaporation and the process by carbonate of am-
monia, a barely perceptible quantity of fixed alkali was Still
Jeft. The acid matter in the other tube was abundant ; its
4a.ste was sour; it smelt like /skater over which large quan-

- * titieii

on SOME CHEMICAL AGENCIES 0? ELi;CTIlICU'T. 33S

titles of nitrous gas have beon long kept ; it did not aifpc* Changes pro- .-^
«olutio^ of muriate of barytes ; and a drop of it placed uppn ^^i'dL hf ^atei-.^
a polished plate of silver left after evaporation a black stain^
precisely similar to that produced by extremely diluted ni-
trous acid.

After these resnitsj I could no longer doubt that some .
saline matter existing in the agate tubes had been the source <
of the acid matter capable of precipitating nitrate of silyeFj^^
and of much of the alkali. Four additional repetition.'^ of
the process, however, convinced me^that there was likewisa^
some other cause for the presence of this last substance;
for it continued to appear to t]}.e. last, in quantities suffi-
ciently-distinguishable, and apparently equal in every casQ,.
I had nsed every precaution ; I had included the tubes iu
glass vessels out of the reach of the circulating air;^ all the
acting materials had been repeatedly washed with distillec^r
Tfater ; and no part of them in contact with- the ^uid had '

been touched by the fingers. .,.....■

The only substance which I could now conceive capabl9,
of furnishing the fixed alkali was the water itself, This^
water appeared pure by the tests of nitrate of silver and,
muriate of barytes; brut potash and soda, as is well known^,
rise in small quantities in rapid distillations ; and the New-
River water, which I made use of, contains animal i\nd ve-
getable impurities, which it was easy to conceive might fnr-
nish neutral salts capable of being carried over in vivid
ebullition.

To make the experiment in as refuied a form as poseibk^^ I
procured two hollow concs_of pure gold containing about 25
grains of water each, thoy were filled with distilled water,'
connected together by a moistened piece of amianthus which:
had been used in the former experiments, and exposed to the
action of a Voltaic battery of 100 pairs of plates of copper
and zinc of six inches square, in which the fluid Avas a solu-
tion of alum and diluted sulphuric acid. In ten minutes the
watet in the negative tube had gained the power of givi^^
a slight blue tint to litmus paper: and the water in the posi-
tive tube rendered it red. The process was continued for
14 hours; the acid increased in quantity during the whole
time, and tlie water became at last very spur to the taste*

Th(?

g2g O^ SOytE CHEMICAL AGENCIES OF ELECTRICITT.

Changes pro- The alkaline proporties of the fluid in the other lube, on
tHciiy in wa^t«r. *^® ^°^*^^^'5 remained stationary, and at the end of the
time, it did not act upon litmus or turmeric paper more
than in the first trial: the effect was less vivid after it had
been strongly heated for a minute ; but evaporation and the
usual process proved that gome fixed alkali was present.
The acid, as far as its properties were examined, agreed
with pure nitrous acid, having an excess of nitrous gas. ^
I repeated the experiment, and carried on the process for
three days ; at the end of which time the water in the tube
was decomposed and evaporated to more than one half of its
original quantity; the acid was strong, but the alkali in as
minute a portion as in the last experiment. It acted indeed
rather more vividly on the tests, on account of the greater
diminution of the fluid, but presented the same results after
being heated. ,

It was now impossible to doubt, that the water contained
some substancein very minute quantities, capable of causing
the appearance of fixed alkali, but which was soon ex-
hausted; and the question that immediately presented itself
was. Is this substance saline matter carried over in distilla-
tion ? or is it nitrogen gas, which exists in minute portions
in all water that has been exposed to air, and which, if an
element of the fixed alkali, would under the circumstance
^f the experiment have been soon exhausted, whilst its ab-
sorption from the atmosphere would be impeded by the sa-
turation of the water with hydrogen?

i was much more inclined to the former than to the latter
supposition. I evaporated a quart of the distilled water that
I had used, very slowly at a heat below 140^ Fahrenheit,
ih a silver still; a solid matter remained, equal to -/^ of a
grain; this matter had a saline but metallic taste, and was
deliquescent vvhen exposed to air : I could not obtain from
it regular crystals; it did not afFect turmeric or litmus, but a
part of it, after being heated red, in a silver crucible, ex-
hibited strong alkaline properties. It M'as not possible to
make a minute analysis of so small a quantity, but it ap-
peared to me to be principally a mixture of nitrate of soda
d iiitrate of lead ; and the metallic substance, it is most

t

Ikely, was furnislK-d by the condensing tiibe of the com-

fiihh still,

The

ON SOME CHEMICIL AGENCIES OF ELECTRICITY. 327

The existence of saline matter in the distilled water being Changei pro- '

ihus distinct, it was easy to determine its operation in the ex- ^V<^.*^ f^X ^^^«"
' •' ^ tncity in water,

periment. I filled the two gold cones with water in the usual

manner ; that negatively electrified, soon attained the maxi,

mum of its effect upon turmeric paper. I then introduced

into it a very minute portion of the substance obtained by

the process of evaporation that has been just described ; in

less than two minutes its effects were evident ; and in five

minutes the tint of the paper was changed to a bright

brown.

I now conceived that by collecting the water obtained in
the second process of slow distillation I should be able to ^

carry on the experiment without any appearance of fixed
alkali, and the trial proved that I was not mistaken.

Some of this water was introduced into the gold tubes^
and the amianthus moistened by it.

After two hours the water in the negative tube produced
no effect upon turmeric paper ; it did produce an effect upon
litmus, which it required great minuteness of observation to
perceive; but it wholly lost the power by being heated
strongly for two or three minutes, so there is every reason
for supposing that it was owing to a small quantity of am- ^
monia.

I made a similar experiment with a portion of the same
water in the tubes of agate that had been so often used, and
I had the pleasure of finding the results precisely the same.

To detail any more operations of this kind will be unne-
cessary ; all the facts prove, that the fixed alkali is not gene,
rated, but evolved^ either from the solid materials employed,
or from saline matter in the water.

I have made many experiments in vessels composed of
different substances, with the water procured by very slow
distillation : and in almost every instance some fixed alkali
appeared.

In tubes of wax the alkaline matter was a mixture of soda,
and potash; and the acid matter a mixture of sulphuric,
muriatic, and nitric acids.

In a tube of resin, the alkaline matter seemed to be prin-
cipally potash.

A cube of Carrara marble of about ^n inch, having tti

aperture

338 ' •'^ *^^^ CHEmcAl. AdKNClES Of ELECTRICITY';

Changes pro- aperture in its centre, was placed in a crucible of platina,
tridty in watei . "^^^^^ ^^^^ filled as high as the upper surface of the cube
with the purified water, the aperture was filled with the
same fluid; the crucible was positively electrified by a strong
Voltaic power, and a negatively electrified wire introduced
into the aperture.

The water soon gained the property of affecting the tint
of turmeric; and fixed alkali and lime were both obtained
from it; and this effect took place in repeated experiments :
the fixed alkali, however, diminished in quantity every time 5
and after eleven processes conducted from two to three
hours each, disappeared altogether. The production oC
lime-water was uniform.

I made a solution of 500 grains of this marble in nitric
acid; I decomposed the mixture by carbonate of ammonia,
and I collected and evaporated the fluid part, and decom«.
posed the nitrate of ammonia by heat. About | of a grain
of fixed saline matter remained, which had soda for its
base.

It M as possible that the Carrara marble might have bee^
recently exposed to sea-water ; I therefore tried, in the same
way, a piece of granular marble, which I had myself broken
from a rock on one of the highest of the primitive moun-
tains of Donegal. It afforded fixed alkali by the agency of
negative electricity.

A piece of argillaceous schist from Cornwall, treated in
the same manner, gave the same result; and serpentine from
the Lizard, and grauwacke from North Wales, both afforded
8oda. It is probable that there are few stone's, tbat do not
contain some minute portions of saline matter, which in
many cases may be mechiinically diffused through their sub-
stance: and it is not difficult to conceive the possibility of
l^is, when we consider that all our common rocks and
strata bear evident niarks of having been anciently covered
by the sea.

I was now able to determine distinctly, tlmtthe soda pro-
cured in glass tubes came principally from the glass, as I
}iad always supposed.

I used the two cones of gold with the purified water and
the amianthus^ the process was conducted a« usual. After

^ (^uartei"

©N tOME CHEltflCAC AGENCIES OF ISEKCTRlCllf'i?, 3g^

•* quarter of an hour, the negatiTelj electrified 'tnT)e did iiot Changes pro^
<;hange the colour of turmeric. I introduced into the top fVx^^ .^^ ^^^
of it a bit of glass ; in a few minutes the fluid at th« surface
rendered the tint of the paper of a deep bright brown,

I had never made any experiments, hi which acid matter
having the properties of nitrous acid was not produced, and
the longer the operation the greater was the quantity that
appeared.

Volatile alkali likewise seemed to be always formed iii
T«ry minute portions, during the fir&t few minutes in the pu^
>ified water in the gold cones, but the limit to its quantity
was soon attained.

It was natural to account for both these appearances,
from the combination of nasceiit oxigen' and hidrogen
respectively; with the nitrogen of the common air dissolved
in the water: and Dr. Priestley's experiments on the ab-
sorption of gasses by water (on this idea) would furnisli an
«asy explanation of the causes of the constant production of
the acid, and the limited production of the alkali; for hi-
drogen, during its solution in water, seems to expel nitro-
gen; whilst nitrogen and oxigen are capable of coexisting
dissolved in that fluid *.

To render the investigation more complete, I introduced
tlie two cones of gold with purified water under the receiver
of an air pump ; the receiver was exhausted till it contained
only -j^ of the original quantity of air; and then, bymeanj;
of a convenient apparatus, the tubes were connected with
an active Voltaic pile of 50 pairs of plates of foiir inches
square. The process was carried on for 18 hours, when
(he result was examined. The water in the negative tube
produced no eficct upon prepared litmus, but that in the
positive tube gave it a barely perceptible tinge of red.

An incomparably greater quantity of acid would have
been formed in a similar time in the atmosphere, and the small
portion of nitrogen gas remainiing in contact with the water
seemed adequate to the effect.

I repeated the experiment under more conclusive circum-
stances. I arranged the apparatus as before ; I exhausted

* Priestley's Experiments and Observations, Vol. I, p. 59.

tht

330 ^^ SOME CHEMICAL AGENCIES OF ELECTRICITX.

Changes pro- the receiver, and filled it with hidrogen gas from a convex
tricitr in water. ^^^^^ airh older ; I made a second exhaustion, and again in,.
troduced hidrogen that had been carefully prepared. Thp
process was conducted for 24 hours, and at the end of thi^"
time neither of the portions of the water altered in the
slightest degree the tint of litmus.

It seems eyident then, that water chemically pure is de-
composed by electricity into gaseous matter alone, into ox-
igen and hidrogen.

The cause of its decomposition, and of the other de-
compositions which h^ve h^en mentioned, will be hereafter
discussed.

III. On the Agencies of Electricity in th(? Decont^pontig^,
of various Compounds.

Action of elec- The experiments th^t have been detailed on the production

liicity m de- ^ alkali from firlass, and on the decomposition of variouk
composingconr . . ^

pounds. saline eo^ipounds contained in animal and vegetable sub*.

stances, offered some curious objects of inquiry.

It was evident, tha't in all changes in which acid and aK
Valine matter had been present, the acid matter collected in
the water round the positively electrified metallic surface;
and the alkaline matter round the negatively electrified me-
tallic surface; and thisi principle of action appeared imme-
diately related to one of the first phaenomena observed iii
the Voltaic pile, the decomposition of the muriate of soda
attached to the pasteboard ; and io many facts which hav^
been since observed on the separation of the constituent
parts of neutrosaline and metallic solutions, particularly
those detailed by M. M. Hisiuger and Berzelius *.

The first experiments that I made immediately with re-
spect to this subject were on the decomposition of solid
bodies, insoluble, or diflicultly soluble in water. From the
eifFectsof the electrical agency on glass, I expected that
Varibu's earthy compounds Mould undergo change nndor
similar circumstances; and the results 6f the trials wef^
i|ecide(J and satisfactory.

'■^ Annales de Clumie, Tom. LI, p. 167.

■"''■ ""'• ' ' two.

ON SOME CHEMICAL ACENCTE!? OP EircYRldlTYi Sof'

Two cups made of compact sulpliate of lime, contaiiiine Action of elec^

. i» ' ... u .,^ J t jA tricity in de-

about 14 gram-measures of water each, wei<fe (Connected to-composiugcora-

gother by fibrous sulphate of lime, Mhich Was moistened by pounds,

pure water: the cups were filled with this fluid; platina

wires from the Voltaic battery of lOQ pairs of plates of six

inches were introduced into them, so that the circuit of elec,

tricity was through the fibrous sulphate of lime. In five

minutes the water in the cup connected with the positive

wire became acid ; that in the opposite cup strongly tinged

turmeric. After an hour the fluids were accurately exw

amined; when it was found that a pure and saturated sow

lution of lime had been produced in the cup containing the

negative wire, which was partially covered with a crust of

lime; and that the other cup was filled with a moderately

strong solution of sulphuric acid.

I procured two cubical pieces of crystallized sulphate of
strontites, of about an inch ; a hole was drilled in each ca-
pable of containing about eight grains of water: the cubes
were plunged in pure water in a platina crucible ; 9-nd the
level of the fluid preserved a few lines below the surface of
the cubes ; two platina wires were introduced into the
holes, which were filled with pure water. The disengage-
ment of gas, when the wires were connected with the bat-
tery of 100, proved that the sulphate of strontites was suf-t
ficiently porous to form a proper conducting chain. The
results were much longer in being obtained in this experi-
ment than in the last: some time elapsed before a sensible
eifect could be perceived ; but the termination was similar.
In 30 hours the fluid in the cavity containing the negative
wire had gained the propefrty of precipitating solution of
sulphate of potash ; and the presence of sulphuric acid in
the other cavity was evident from its effect upon solution
of muriate of barytes.

I made an experiment upon fluate of lime under like cir-
cumstances; but the crystallized fluate not being equally
permeable to moisture, the two cavities were connected by
moist asbestus. This decomposition was likewise very
slow; but in the course of two days a pretty strong solu-
tion of lime was obtained in one tube; and an acid fluid
'}W the otherj which precipitated acetitc of lead, and left a
scot upon the glass from which it had been evaporated.

Sulphat*

333 ON lOMX CHEMICAI, AGENCIES OF EtECTftlClTr^

Axjtlon of else- Sulphate of barytes^ as might be supposed, proTed much
•raiposingcom- ''^^■'® ^*®<^"^* ^^ decomposition than either sulphate of
jdunds. strontites oi^ fluate of lime. I had made four or five ex-

periments upon it, Avith the same kind of apparatus that
had been applied to the fluate of lime, befpre i was able to
gain decided results. In the last process pcrfoi*med on thi^
substance, two pieces of a large single crystal were hol-
lowed by grinding, so as to contain about five grains of
water each ; they were connected by moist asbestusj and
constantly subjected during four days to the strong aciion
of a battery of 150 pairs of plates of 4 inches square. As
the water diminished, its place was wipplied by new qtian^
tities. At the conclusion of the experiment the fluid on the
i>ositive side of the apparatus instantly reddened IHmusj
tasted Tcry sour, and gave a distinct precipitate with a so-
lution of muriate of barytes; the water on tke other side
deepened the tincture of turmeric; but did not render so-
lution of sulphate of potash turbid. There was a small
quantity of white crust, however, on the sides and tha
bottom of the cavity, and I conceived that this might be
the barytes, which, during the extremely slow decompo*
sition, would have combined with the carbonic acid of the
atmosphere. To ascertain if this had been the case, I in-
troduced into the cavity a drop of diluted muriatic acid ;
a slight effervescence appeared, and the fluid obtained occa«
, sioned a distinct white cloudiness in solution of sulphate of
soda.

In all these cases the constituent parts of the bodies
newly arranged by the effects of electricity existed in con-
siderable quantities, and exposed on a latge surfitce to its
action, I had great reason to believe, from the trials M'ith
distilled water in different vessels, that very minute portions
of acid and alkaline matter might be disengaged by this
agency from solid combinations, principally consisting of
pure earths.

This part of the investigation was easily elucidated.

For a purpose of geological inquiry, which on a future

occasion I shall have the honour of laying before the

Society, I had made a careful analysis of a specimen of

fine grained basalt from Port Rush in the county of Antrim,

tN SOME CHEMICAL AGENCIES OB ELECTRICItY, 335

hy meaas of fusion with boracic acid : it afforded in 100 ActVm of eieso

parts Sf parts of soda, and nearly { a part of muriatic ^^^^^^^ *" ^^'
r z ir 7 ^ i r- Composing coqjjb

acid, withi 15 parts of lime. This stone appeared to me pounds.
Tery well fitted for the purpose of experiment: cavities
were drilled in two pieces, properly shaped ; they contain,
ed about 12 graias of water each ; they were connected by
moistened amianthus, aud the process conducted as wsns^
with a power of 50 pairs of plates. At the end qf ten
hours the result was examined with care. The fluid that
had been positively electrified had the strong smell of oxi-
muriatic acid, and copiously precipitated nitrate of silver ;
the other portion of fluid alFected turmeric, and left by
evaporation a substance which seemed to be a mixture of
Jime and soda.

A part of a specimen of compact zeolite, from the Giant's
Causeway, which hy analysis had given 7 parts in 100 of
soda, had a small cavity made in it ; it was immerged in
pure water in a crucible of platina, and electrified in the
same manner as the cube of Carrara marble, mentioned in
page 328. In less than two minutes the water in the cavity
had gained the property of changing the colour of turme-
ric; aad in half an hour the solution was disagreeably
alkaline to the taste. The matter dissolved proved to be soda
and lime.

Lepidolite, treated in the same way, gave potash,

A piece of vitreous lava, from Etna, gave alkaline mat-
ter, which seemed to be a mixture of soda, potash, aud
lime.

As in these trials the object was merely to ascertain the
general fact of decomposition, the process was never con-
ducted for a sufEcient time to develope a quantity of alka-
line matter capable of being conveniently weighed, and of
course any loss of weight of the substance could not b^
determined.

I thought it right, however, to make one experiment of
this kind, for the sake of removing every possibility of
doubt on the source of the diflisrent products ; and I se*
lected for this purpose glass^ as a substance apparently in,
soluble iu water, and not likely to afford io auy way er-
roneous results.

3^ ON SOME CHEMICAL AGENCIES Of EtECTRIClTT.

Action of elec- Th^ bataiice that I employed was made for the Roya!

iTicity in de- ini^titutiOQ, by Mr. Fidler, after the model of that belong-

composing com- i t^ r^

poondi. J»g to the Hoyal Society 5 it turns readily with ^a^ of a

grain when loaded with 100 grains on each side; a glass
tube with a piatina wire attached^ weighing 84 grains ^^^
was connected with an agate cup, by amianthus ; they were
tilled with purified water, and electrified by a power from
150 pairs of plates, in such a way that the piatina in the
glass tube was negative. The process was continued for
four days, when the water was found alkaline. It gave by
evaporation and exposure to a heat of about 400'' Fah-
renheit, soda mixed with a white powder insoluble in acids,
the whole weight of which was ^W of a grain. The glass
tube carefully cleaned and dried weighed 84 grains, ^y^.
The dilFerence between the loss of weight of the tube and
the weight of the products in the water may be easily ex-
plained : some minute detached particles of amianthus were
present, and the soda must have contained water, a sub-
stance which it is probably perfectly free from in glass.

Having obtained such results with regard to the disengage-
ment of the saline parts of bodies insoluble in water, I made
a, number of experimewts on soluble compounds: their de-
composition was always much more rapid, and the pheno-
/ mena perfectly distinct.

In these processes I employed tlie agate cups with piatina
wires, connected by amianthus moistened in pure water ;
the solutions were introduced into the cups, and the elec-
trifying power applied from batteries of 50 pairs of plates,
in the usual way.

. A diluted solution of the sulphate of potash treated in this
manner, produced in four hours at the negative wire a weak
lixivium of potash; and a solution of sulphuric acid at the
positive wire.

The phenomena were similar when sulphate of soda, ni-
trate of potash, nitrate of barytes, sulphate of ammonia,
phosphate of soda, succinate, oxalate, and benzoate of am-
monia, and alum were used. The acids in a certain time
collected in the tube containing the positive wire, and the
alkalies and earths in that containing the negative wire.

Solutions of the muriatic salts, decomposed in the same
way, uniformly gave oximuriatic acid on the positive side.

When

ON' SOME CHEMICAL AGEI^CIES Ot EtECTRIClTYk 335

,' When compatible mixtures of neiitrosaline solutions cotl* Action of elec-
faining the common mineral acids were used, the different tncity in de-
acids and the different bases seemed to separate together in pounds.
a mixed state, without any respect to the orders of af-
finity.

When metallic solutions were employed, metallic cry-
stals or depositions were formed, as in common galvanic
experiments, on the negative wire, and oxide was likewise
deposited round it; and a great excess of acid was soon
found in the opposite cup. With solutions of iron, zinc,
and tin, this effect took place, as well as with the more
oxidable metals: when muriate of iron was used, the black
substance deposited upon the wire was magnetic, and dis-
solved with effervescence in muriatic acid ; and when sul-
phate of zinc was used, a gray powder possessed of the
metallic lustre, and likewise soluble with effervescence,
appeared; and in all cases acid in excess was exhibited on
the positive side.

Strong or saturated saline solutions, as might have been
expected, afforded indications of the progress of decompo- ^

sition much more rapidly than weak ones ; but the smallest ,

proportion of neutrosaline matter seemed to be acted on
with energy.

A very simple experiment demonstrates this last principle.
If a piece of paper tinged with turmeric is plunged into
pure water in a proper circuit, in contact with the negative
point, the very minute quantity of saline compound con-
tained in the paper affords alkaline matter sufficient to give
it instantly a brown tint near its point of contact : and acid
in the same manner is immediately developed from litmus
paper, at the positive surface.

I made several experiments, with the view of ascertain-
ing whether, in the decompositions by electricity, the se-
paration of the constituent parts was complete from the
last portions of the compound; and whenever the results
were distinct, this evidently appeared to be the case.

I shall describe one of the most conclusive of the experi-
tnents: a very weak solution of sulphate of potash, con-
taining 20 parts water and one part saturated solution, al
64"', was electrified in tlie two agate cups by the power x>f

50 paii't

335 ^^ »OMje CHEMltJAL AQtIfCli:* Of BLlCTftlCITT,

Agtwa of eleo 5Q pairs of plates for ihrQe days : the connecting amianthuft^
Jlm/osingcom-^^*'^^ ^^'^ been niobteacd with pure water, was remoTedy
Itouuds. washed M'ith pure water, and a^ain applied, tAvice every

day; by this precautioA the presence of any neuiral salt
that might adhere to it, and disturb the results, was. pre.
\ented. The alkali obtained in this process in the solution
had the properties of pure potash ; and when it had been
saturated with nitric acid it gave no turbidness by mixtura
with solution of muriate of barytes : the acid matter ex-
posed to a strong heat evaporated without leaving any re«
siduum.

IV, On the Transfer of certain of the constituent Parts of

Bodies by the Aotion of Electricity.

Transference of M. Gautherot has stated*, that in a single galvani«

certain consti- circle of zinc, silver, and water, in an active state, the oxid«
tuent parts of . . - , . , ., \ -^r -xt

bodies by elec- o* zinc formed is attracted by the silver t ; and M. M.

tricity, Hisingcr and Berzelius detail an account of an experiment,

in wliich solution of muriate of lime being placed in the

' positive part of a siphon, electrified by wires from a Voltaic

. pile, and distilled water in the negative part, lime appeared

in the distijlcd water.

These facts rendered it probable, that the saline element*
evolved in decompositions by electricity were capable of
being transferred from one electrified surface to another,
according to their usual order of arrangement; but to de«
monstrate this clearly, new researches were wanting.

I connected one of the cups of sulphate of lime, men»
tioned page 331, with a cup of agate by abestus ; and, filling
them with purified water, made the platiiia wire in the cup
of sulphate of lime transmit the electricity from a power
of 100; a wire in the agate cup received it. In about
four hours a strong solution of lime was found in the agat*
cup, and sulphuric acid in the cup of sulphate of lime. Bj
reversing the order, and carrying on the process for m
similar time, i^Q sulphuric acid appeiired in the agate cup,
and the solution of lime on the opposite side.

Many trials were made with other saline substances, witU

* Annales.de Chimle, Vol. XXXIX, page 203.
t Ibul. Vpl. JLI^pag^ 171-
^ analogpu*

t

43N SOME CHEMICAL AGENCIES OF ELECTRICITY. -337

a^ialogous results. When the compounds of the strong Transference of
tniueral acids with alkaline or alkaline-earthy bases were J^ent pa^ns of'
introduced^ into one tube of glass, distilled water connected bodies by «lec-
hy amianthus being in another tube, both connected by ^"^''^"
wires of platina in the Voltaic arrangement, the base al-
ways passed into the distilled water when it was negative,
and the acid when it was positive.

The metals and the metallic oxides passed towards the
noi^ative surface like the alkalies, and collected round it.
in a Case in which solution of nitrate of silver was used on
the positive side, and distilled water on the negative, silver
appeared on the whole of the transmitting amianthus, so
as to cover it with a thin metallic film.

The time required for these transmissions (the quantity
and intensity of the electricity, and other circumstances
remaining the same) seemed to be in some proportion as the
length of the intermediate volume of water. Thus when,
with the power of 100, suiphate of potash was on the ne-
gative side, 9,nd distilled water on the positive side, the dis-
tance between the wires being only an inch, sulphuric acid,
in sufficient quantity to be very manifies.t, was foumi in the
water in less than five minutes: but wheit^ the tubes were
connected by an intermediate vessel of pui^ water, so as to
make the circuit eight inches, 14 hours were re^qijired to
produce the same effect.

To ascertain whether the contact of the saline solution
with a metallic surface w^s necessary for the decomposition
and transfer, I introduced purified wg-ter into two glass
tubes; a vessel containing solution of muriate of potash
was connected with them respectively by amianthus ; and
the arrangement was made in such a way, that the level pf
both the portions of purified water was higl^er than t^e
level of uid saline sohition.

In this case, the saline matter was distant from each of
tlie wires at least |- of an inch ; yet alkaline matter soon ap.-
pciired in one tube, and acid matter in the other : and in
16 hours moderatelj strong solutions of potash, and of
juuriatic acid hgid been formed.

In this case of electrical transfer or attraction, the acid
,-dAu\ alkaline matter seemed to be perfectly pure; and I am

Vol, XVIII.— Suppj^^ewknt. Z incline^

S38

OS SOXfE CITEMICAL AGENCIES OF ELECTRICITY.

Transference of inclined to believe, that this fs uniformly the case in'all ex.
certain consti- . , if x% i /-» /..... .",.,,

periments carefully made. One of the instances in which I

tuent parts of
bodies by elec-
tricity.

conceived acid most likel}^ to be present, was in the transfer
of magnesia from sulphate of magnesia in the positive tube,
to distilled water in the negative tube. I examined the
case, taking care that the distilled water was never upon a
lowxr level than the saline solution : the process was con-
tinued for some hours, till a considerable quantity of mag.
nesia had appeared. The connecting amianthus was re-
moved, and muriatic acid poured into the tube: the satu-
rated solution did not precipitate solution of niuriate of
barytes. '

I endeavoured to ascertain the progress of the transfer,
and the course of the acid or alkaline matter in these decom-
positions, by using solutions of litmus and turmeric, and
papers coloured by these substances; and these trials led
to the knowledge of some singular and unexpected cir-
cumstances.

Two tubes, one containing distilled water, the other so-
lution of sulphate of potash, were each connected by ami-
anthus with a small oz, measure filled with distilled water
tinged by litmus : the saline solution was negatively elec-
trified; and as it was natural to suppose, that the sulphu-
ric acid in passing through the water to the positive sid«
would redden the litmus in its course, some slips of mois-
tened paper tinged with litmus were placed above and below
the pieces of amianthus, directly in the circuit. The pro-
gress of the experiment was minutely observed; the first
effect of reddening took place immediately above the posi-
tiTe surface, where I had least expected it; the red tint
slowly diffused itself from the positive side to the middle of
the vessel, but no redness appeared above the amianthus,
or about it, on the negative side, and though it had hcen
constantly transmitting sulphuric acid, it remained unaf-
fected to the last.

The order of the experiment was changed, and the saline
solution placed oh ihe positive side ; a solution and papers
.tinged with turmeric bein^ substituted for those tinged with
litmus. The effect was precisely analogous; the turmeric
became brownf ^st oear ific negative wire, and ao change

took

ON VARIOUS che:.iical action*. SS§-^

loflk place ia the intermediate vessel near the ppsitive
wire.

in anpther process, the two gUss tubes were tilled with
solutijon af muriate, of soda, and the intermediate vessel
Avi<h soJutioiji -ojf sulphate of silver: paper tinged with tur-
nieiic was placed on the positive side, and paper tinged with
litmus on the negative ^ide ; as soo^,^ the electrical circuit
was complete, soda began to appear in the negative tube,
^nd oximuriati/: acid in the positive tube, and the alternate
products lyere exhii^ited passing into the solution of sul-
phate of silver, the muriatic acid occasioning a dense heavy
precipitate, and the soda a more diffused and a lighter one ;
but neither the tiurineric transmitting the alkali, nor the
litmus transmitting the acid, had their tints in the slightest
degree altered.

(To he continued.)

II.

Extract of a Letter from Mr. J. M. Haussmavn to
J/r. Bertkollet*.

HEN I published ray memoir on Stahl's alkaline tine- Superoxige-
ture of steel, I imagined that this superoxigenated sulphate "^^q/"^^^^**
of iron would not fail to be examined moie minutely : but '

finding myself disappointed in this respect, I cannot re-
frain from again calling to mind some of its properties that jts properties,
appeared to me striking. These are its being wholly insipid
to the taste, when completely deprived of its water of cry-
utallization : and of acquiring astringent powers, surpassing
those of a<ny other astringent known, as soon as it has im- '''^\[ ^''^^V
Mbed moisture from the air, or been dissolved in water.
This superoxigenated sulphate of iron produces the most
beautiful prussian blue possible; and it may be used witt
Advantage in dyeing, particularly for blacks.

I read With pleasure Mr. Thenard's paper, but I cannot Nitm^Voj^wcJ
h^ of his opinion with respect to the nitrate of iron satu- '^O'staliiz^^
jated with ox^en, crystals of which I can easily produce
* Annales de Ghimie, Vol. LV III. p> 182, May, 180C.

i % >yji.th9v^

S40 ^^ YARIOUS CirrMICAL ACTIONS.

'i^Vthout diluting the vnlric acid of 40^ of Messrs. Coustou
and Co. at Paris. I use this same acid, to convert sugar

Patty matter into Q:?alic acid; and, vhcther I employ it of its full

torn sugar. strength, or diluted with equal parts of water, I constantly
obtain a little greasy matter, when I conduct the process in
the large way on a vapour bath.

Sugar treated On treating the same sugar three times snccossiTcly with

with mtncaad.gqyal portions of this^cid^ either concentrated or diluted,
the first portion occasions a broM-n colour, and produces
a smell of burnt sugar. And when the action of the nitric
acid has (icased, we already perceive some of this grease
swimrning at the top; and it appears to be farther in-
creased by the successive addition of the other two portions
of acid, which cause the brown colour and smell of burnf
sugar to disappear, forming a great abundance of oxalic
acid, and a small quantity of the laalic and citric acids.
Perhaps, if the gasscs were collected, we should find a littl«
acetic acid also.

No oil from it '^^ satisfy myself whether the sugar gave rise to the for*.

by boiling. mation of the grease, 1 examined one of the largest sized
sUjgar-loaves, wJiieh I commonly use. I divided it into two
equal portions, the first consisting of the outer part of the
loaf, the second of the inner. Kach of these portions 1
boiled for a few minutes in three times its weight of water.
No grease swam on either of these solutions of sugar, after

Frobably from they were cold; but as they were not very clear, I began
^^^^' to suspect, that, the sirup for common sugar being clari-
fied with bullock's blood by the sugar ?3aker«, the gelatinous
part of this animal substance unites in some measure with"
-the particles of sugar by a forced and confused crystal-
lization, and, when acted upon by nitric acid, may give

None from tine rise to the separation of grease. 1 was not long before!
sugar or cuudv. . ^ , ,i. , . *

satisned myself, that my suspicion was just, for, on making

oxalic acid with some fine w hite sugarcandy, and at th»

game time with the finest loaf sugar I could procufCj

neither of these showed any signs of grease.

Fat oils sepa- Fat oils in their natural state have not the least action
rated from -ooap? , , • , • i , , .i. ,

byanacidac- ^^^ asphaltum, jews' pitch, or copal: but if they be re*

quire a solvent duced to a soap, and afterward separated by any acid,

^ '^' they not only exert a strong solvent power on these sub-

^tancds^

ON VAniOUS CHEMICAL ACTIONS. 241-

stances, but they further acquire the property of decompo-
sing acetate of lead, as well as other metallic acetates, and
of combining readily with their oxides, the acetic acid of
which is given out. These oils thus separated would produce
the same effect perhaps on other metallic salts. In general This common
all fats, resins, and turpentines, combine better with ^.^.^^^^5
other substances, after they have been reduced to soap and
separated by an acid, than in their natural state. Wax
comports itself in the same manner. A knowledge of this This oil exposed

effect induced me to subject to the action of the process ^? ^^^ ^^*i°" ^
- - . ,. . - •' ,, . ^ ., nitric acxd.

for forming oxalic acid a small portion of oil separated

from Marseilles soap, which I mixed with sugar previously
powdered. At the end of the operation I found, that the
oil had acquired the consistence of suet, and that it had
assumed a yellowish colour and a rancid smell, retaining
the property of swimming on water. This grease, having
been exposed to the same process a second time, had its
rancidity increased, contracting at the same time a little of
the smell of wax; and its specific gravity became so great,
that, after it had been well washed and perfectly freed from
acidity, it sank to the bottom of water, Mithout having
lost its property of being soluble in alcohol.

My memoir on indigo shows, that I had long ago built Indigo-
great hopes on the action of nitric acid with respect to
other substances, and it is with great pleasure I perceive,
that Messrs. Fourcroy and Vauquelin have pursued my re-
searches on indigo exposed to the action of nitric acid
with more success than I obtained- I could only have
wished, that Mr. A. Laugier had passed me over in silence
in his abstract of the paper of those learned chemists, for
my way of thinking in cliemistry is totally difi'erent now
from what it was eighteen years ago. "When Mr. Laugier
quoted me, he should not have forgotten that passage in my
paper, which mentions the results of treating indigo with
nitric acid, results that struck me so forcibly, as to induce
me to recommend them to the attention of chemists.
Neither had I omitted to mention the phenomena of the
deflagration of the mixture, with the throwing of the glas«
rod out of the evaporating vessel. As a little time before
I undertook these experiments I had extracted the benzoic

acid

$a ON VARIOUS CIIKMICAL ACTION*^

acid irom its gura, I was too well acquainted with its smell,
ftot to have distinguished it in purifying and drying the re*
siduums of indigo treated with nitric acid, if my occupa-
tions as a manufacturer, which prevent me from gratifying
my iuclination for chtTinical experimenls, had not proved an
obstacle. Perhaps too I should not have missed the dis-
covery of the detonating property of the bitter portJon of
the residuum : but it seems I was not born to make a figure
I in the career of. discovery,

Aysenical allca- With respect to the solution of indigo by means of an
indjffo*^"^^^" ^ alkaline solution of red arsenic, which is used in calica
printing, 1 no longer observe the proportions indicated in
my memoir. 1 simply make a caustic alkaline solution of
red arsenic, to which I add, while it is yet boiling, a suf-
ficient quantity of brayed indigo, to obtain a very deep
shade, which it is easy to render lighter afterward, ac-
cording to the object proposed, by diluting the solution of
indigo with a weak lixivium of caustic potash. Tliis
i$ preferable to pure water, because it retards in some
measure the absorption of oxigen froaii the al-mosph^.re,
and cOnseq;U<3ntIy the regeneration of the indigo. The
Cav.t:onsre- beauty of the blue in the ; calicoes requires, that this
pifcation!'^^*^^"^^^^^'***^'^ should be neither too slow nor too speedy.
The too slow absorptijon arising from too great exteiss ©€
caustic alkali ought to be avoided in pencilling blues, as weM
as in the blues in block- printing, which are procured by
passing the goods, first printed with bra/ed. indigo miwed
with a gummy solutioti of sulphate of iron, alternately
through vats of caustic potash, water, siilphate of iron at
a minimum of oxidation, and lastly a vat acidulated by
sulphuric or muriatic acid.

Indigo and mw- On e?[posine to a sand-heat a mixture of brayed indiffa
tiate of tin. . ^ . . . • ^ . . , , . . .

With a muriatic Solution of tin oxided at a mimmum, m

which there is an excess of acid, the colouring substance is
decomposed, occasioning the evolution of a gas-of an in-
supportable and noxious smell, whlcli deserves to be
examined.
Eulphate of in- . Jf indigo treated with the muriatie solution of tin oxided
mteoi^tiii" at .> minimum, without the assistance of a caustic alkali,
f cirinot be of. aiiy. use -in .d)dng, it is not the same with

sulphate

DISOXIDING PRINCIPLE IN DISTILLED WATERS. 343

sulphate of indigo, treated or mixed in difl'erent propor-
tions Avith the same solution of tin, after having previously
absorbed sulphuric acid. This is employed in the manu-
facture of printed goods for producing all sorts of blues
and greens.

III.

Observations on the Distilled Water of common Borage;
hy Philip Antony Steinacher, Member of the Phar-
maceutic Society of Paris *.

-OITHERTO no particular property had been observed Borage wat<8f

in borage water, except its depositing mucous filaments after

being kept some time. Some that I distilled on the 7th of

June, 1806, exhibited the following remarkable properties.

The borage was very fresh, succulent, and immediately after

being very finely shred was put into the body of a tinned

copper alembic. Two parts of distilled water were poured very carefully

on it, which moistened it sufficiently. The head of the still ^^^*^^^^^*

was put on, and a receiver adapted to it, both of which

were previously rinsed clean with distilled water. The.dis-

tillation was commenced immediately with a heat so gentle,

that 20 or 30 seconds intervened between the fall of the

successive drops. Only half a part of water was drawn

off, which was limpid and colourless, and smelt and tasted

strongly of borage, at the same time having another smell

resembling that of a cucumber.

This water neither reddened litmus paper, nor turned Reddened infu-
green paper tinged with an infusion of red roses ; but it®'°^ *"

perceptibly reddened an aqueous infusion of litmus, which
liad been diluted with distilled water so as to appear of a
pure blue.

It rendered lime-water turbid instantly. Precipitated

A few drops of pure rectified sulphuric acid, distilled al- 1™«-
most to dryness, and diluted with distilled water, produced ^cid eiftmscIX
after the expiration of a few minutes a disengagement of

* Aopales de Chimie, VoI.LX, p. 83, October, 1806.

soaije

^44

plSOXlTilNG PRIXCIPLi: IN DIStlLLXD WATER*.

some very sfnall bubbles, withont emitting any nitrotis, mu*
riatic, or acetous smell, and without disturbing its trans-
parency.
A6tion of other It instantly whiteiied the aqueous solutions of oxalate
^®^^" of ammonia, muriate of barytes, nitrate of lead, and sul-

phate of silver *.
Oxigenized " The oxigenized muriate of mercury, purified by slow
Mercury 'con- sublimation, produced in it a copious white precipitate. At
venedby it into the expiration of half an hour 1 added lime-water in excess,
muna e. ^j^j^.]^ increased the quantity of the precipitate, and did not
turn it yellow even in twejity-four hours; which it would
infallibly have done, if the oxigenized muriate of mercury
had not been converted into muriate at a minimum.
wHh acidsul- Finally, having mixed Mith it some acid sulphate of mer-
phate of mer- cury in a liquid state, made by dissolving the yellow sulphate
oS precipi- ^^ sulphuric acid, the addition of caustic potash purified by
t*te. alcohol separated from it in a quarter of an hour flocks of

an opal colour ; while the same alkali, added to the same
sulphate of mercury without borage water, immediately
■ formed in it yellow flocks +.

prtnoiples con- Hence it follows, that my borage water, distilled with so
tamed in it. much care, and by a heat so gentle, contained carbonic
acid, sulphate of lime, and a disoxiding principle.

Siilnhate of * Sulphate of silver is decomposed by the action of sulphate of

silver decom- lime. The following experiment is a direct proof of this. I took
f o^ed by that sQ^e very limpid lime-water, and added a few small drops of pure
sulphuric acid. The solution remained clear, and had an excess
of acid. To this I added a little of my acid sulphate of silver>
which immediately occasioned a flocculent precipitate. After this
Forms an inso- had been washed, it was not soluble in muriatic acid. This fact
with^out'ra* 'a- P'"^^'^' ^^^^^ ^^^ oxide of silver enjoys a very considerable power of
lie acid. cohesion, and renders me very circumspect in forming a judgment

of the experiments for deciding the presence of muriatic acid in
delicate fluids from the single phenomenon of precipitation by
jn»'ans of any solution of silver, and without examining the other
circumstances, that might occasion the insolubility of the oxide of
silver.
Erratum in t According to Fourcroy's Chemistry, the sulphate of mercury

Foiircroy'sChft-with excess of oxide is precipitated .gray by the alkalis; but this
^^' mu'^t be an errour of the press, our iilu^trious professor having before

shown, that this property belonged to the neutral sulphate of mer-
cury, which he had discovered.

I must

0N ACETIC ACID. 345

I must observe, that several parcels of borage, gathered Some borage
on different soils, and not so fresh, did not exhibit the same^''^^ ^^^ ^'
phenomena in an equal degree. As to this disoxiding prin- Other distilled
ciple, which has a sensible effect on mercurial solutions, I t^jg ^^^^^ ^^^^^
hate found it in several other distilled waters, particularly ciple.
in the water of silver weed, potentilla anserina^ and strong
scented lettuce, laciuca virosa. The water of the last- Wild lettuce
mentioned plant holds in solution besides a fetid volatile oil,
which is rendered visible by adding rectified alcohol at 37^.
It is no wonder therefore, that these distilled waters are ca- Hence then
pable of producing some Q^^ct in the art of dyeing* : they and in some
must be of use likewise in some sthenic diseases. diseases.

IV.

A Memoir on Acetic Acid; hy Mr. J. B. Trommsdorff f.

The object of Mr. Trommsdorff was, to know whether Nitrogen said

*' ^ to be one ot the

azote make a part of the acetic acid, as Proust asserted, principles of

Having considered what is at present known respecting the^^^^^^^^*^"^ ^Y
composition of ammonia, and of vegetable acids, he was
justly surprised to find in Mr. Proust's paper, that he had
found ammonia and prussic acid in decomposing acetates.
Accordingly, notwithstanding the known accuracy and sa-
gacity of the chemist of Madrid, he was desirous of satis-
fying himself of the existence of azote in concentrated ace-
tic acid. The importance of the fact, and a love of truth,
led this indefatigable chemist to make a similar research.

Before relating the processes Mr. Trommsdorff employed,
i^ may be proper to give a succinct statement of the objec-
tions, that occurred to him.

If, says he, in the distillation of acetates ammonia be Objections,
formed, it is evident that they contain azote; but whence

* On consulting the anecdotes that Mr. Deyeux has published Distilled wtttrs
On distilled waters, in No. 168 of the Annales de Chimie, it ap.actonsiJk
. pears, that he found the distilled water of silver-weed had a decided
*<< ^action on the silks that he used to make gauze.

■ t Annales de Chimie, Vol. LVllI, p. IPO, May, 180(J.—
Abridged from the Berlin Journnl by Mr. Bergman.

,5

346 , ON ACETIC ACID.

can this principle be derived ? Is it from tlift basft^' But (his
cannot be, since ammonia was equally obtained from ace-
tate of lead. In this case it could be furnished only by the
acetic acid; or it must be allowed, that azote is only a mo-
dification of hidrogen.
D(ws nitrofjen He then inquires whether azote occur as frequently among
tMe aHlds^^^^' ^'^-^^^^^^^ acids, as among 'Minimal acids: because, if it be

so, their classification should be altered.
Very pure sub- In repeating the experiments of Mr. Proust, it appeared
ployed. " essential to Mr. Trommsdorff, to eiri])loy only very pure
substances. Accordingly, in order to have acetic acid in
the purest state possible, he decomposed the acetate of pot-
ash by sulphuric acid; heathen saturated this acid with car-
bonate of soda well purified, and efaporated the saline so-
lution in a silver basin. The salt obtained, which he put
into a bottle with a ground stopper, was extremely white.

In preparing the acetates Of potash and of lead he em-
ployed similar precautions.
Tliese distilled. lie took eight ounces of each of these salts, and intro-
duced them separately into three strong glass retorts. These
retorts were placed on the open fire of a furnace, and to
each was adapted a receiver, from which issued a glass tube,
terminating under a jar for receiving the gasses that should
come over.
The products. ' The products were, as every body knows, an acidulous
«thereous fluid mixed wilh oil. The alkali and carbone re-
mained in the retort; and in the decomposition of the ace-
tate of lead nothing of this salt remained but the lead ox-
ided.
The alkalis pro- Thus by the predisposing affinity of the alkalis for car-
noted thede- Jjqj^j^ acid, these determined the decomposition of the acetic
composition of ' ^ ^ ,

the acid, acid, to give rise to the formation of carbonic acid. The

oxide of lead on the contrary, not having so great an affi-
nity for carbonic acid, gave out the acetic acid in its greatest
purity.
How does the '^'^^ autlior asks, whether the metallic base yielded up
metal act? oxigcn to burn the carbone ; or whether the attraction be-
tween an oxide and an acid be less powerful than between
an acid and an alkali. To answer this question, he would
wish a great number of experiments to be made.

Th^

ON ACETIC ACID* 347

^ 'J'he ga^s^ <on examination emitted tio ammoniacal smell, No ammonia
it being merely empyrcumatic and penetrating. The liquids j"-^°
had the same smell, and none of the chemical tests could
detect the presence of ammonia in them.

The repiduums, which according to Mr. Proust contained or in the resi-
prussiate, were nothing but pure alkaline carbonate; or
pare oxide of lead.

Mr. Proust, on examining the residuum of acetate of From the ace-
fVotash, says, that he had a residuum consisting in part of p^o^Jt obtatned
prussiate, in part of carbonate of potash. Mr. Tronmis- prussiate and
dorff expected to find these two salts ; but, after having ^^^^^0"^^^
broken the retort, he found only a homogeneous coal, which
afforded him neither ammonia nor prussic acid, and which
had no smell of either of these substances. Yet we know
how easy it is to distinguish the smell of this acid wherever
it exists in a free state.

Mr. Proust adds, that the residuum of the acetate of The prn'sic
potash was so saturated with prussic acid, that its bitterness jidu^n^ very*^
was as striking as if tKe acid had been combined directly apparent.
with the alkali ; whence Mr. TrommsdorO' infers, that he
must have employed common vinegar in his experiments.

To distinguish the products resulting from the decompo- Vapour of ace-
sition of acetic acid, Mr. TrommsdortF passed the vapour [J^j.^['^^,P^''j;"^'J
of it through a red hot tube, which afforded him nothing tube.
but carbonic acid gas, carburetted hidrogen gas, and a small
quantity of an empyrcumatic liquor, without ammonia, and
without prussic acid. These substances were equally ab-
Rent in the residuums.

He afterwards examined attentively the ethereous acid u- Acetic ether ob-
lous fluids mingled with oil. These he distilled over carbo- fy'jjjg ^^^^ \l^^^'
nate of potash, and obtained an ethcr^ which, from all its quors.
properties, appeared to be true acetic ether.

The results of his experiments are :
. 1. That the presence of azote in acetic acid is not proved. General con-

2. That pure acetates, when distilled, give out neither
s^nmonia nor prussic acid,

5. That pure acetic acid has its nature very little altered
by passing through red hot [glass] tubes.

4. That, in an iron tube, it is completely decomposed
jtito carbonic acid gas, and carburetted hidrogen gas.

5. THi^

348 MACHINE r«R SPLlTtlNa SKINS.

Constituent 5. That the constituent parts of acetic acid are demon*

strated to be oxigen, carbone, and hidrogen.

Acetic ether. 6. That the ethereous fluid is similar to others in its ge-

neral properties. The author considers it as a medium be*

Acetic acid con- twcen alcohol and ether. That as acetic acid is changed in

vertibic into . , , i . ,

•xallc. part into ether, and this, when treated by nitric acid, is-

transformed into oxalic acid ; the conversion of acetic acid

into oxalic is demonstrated, though it is true indirectly.

And lastly, that it is probable Mr. Proust did not employ

pure acetates in his experiments ; or else the ethereous and

Tery penetrating smell led him to believe, that ammonia was

present.

Account of an En<rine for splitting Sheep Skin:<i : by Mr,
Bexjamin Stott, of Bermondset/ Street*,

Advantages of 1 HAVE invented an engine for the purpose of splitting
splitting skins. ^^®^P skins, that is, of making two good skins out of one.
The former and common mode of dressing skins is, to shave
one side off, reserving the shavings for glue pieces ; whereas
by my method, these shavings are all taken off in one piece,
forming a good skin of leather; and thus, independently
of the advantage arising to the proprietor, an additional re-
venue will be caused to the nation, in proportion to the
increase of leather made.
Description of Pi. IX, Fig. 1. A, the barrel of cast iron (having wooden
t e engine. ends) round which barrel the skin is wrapped, and kept close
by means of pins run through the edges into the wood, as
at ^, e, Fig. 2. B, (Fig. 1) an iron running in a groove
along the barrel, catching in a hole at c, and fastened dowr^
at the other end by a hook fixed in the end of the barrel, the
bar having points in it (as shown at B, Fig. 3,) under
which the edges of the skin are fastened (as seen at D,
Fig. 2). F, F, (Fig. 1 and 2) bars fixed across each end of
the strong wooden frame G, G, G, G, over which the barrel
is supported on friction-rollers, as at /i, A, (Fig. 2) which

♦Transactions of the Society of Arts, vol. xxiv, p. 133. The
St^iety voted Mr. Stott twenty guineas for this invention.

.1-

eJ-

FRl.VClPLr.S OF SULPHURIC ACID. 349

run on a slip of brass, moveable under the screws %"j e,
to adjust the barrel to the knife. K, K, (Fig. 1 and 2) a
strong bar of cast iron, to which the knife is screwed,
moving lengthwise on friction-rollers between the pieces of
wood L, L, L, L, on the frame G, as at K, (Fig. 4). The
pieces of wood L, L, L, L, are each moveable under two
icrews, by which they are adjusted to steady the motion
of the knife-bar. M, M, (Fig. 1 and 2) is a roller at the
back of the knife, to which it is kept close by a weight N,
at each end, acting over pulleys, as atO, (Fig. 2) suspended
from the slider p, between which the roller is placed ; by
drawing the spare skin over this roller, as it is cut off, it
keeps both sides of the skin equally up to the knife, and
makes it cut more uniform. Q, Q, is a lever acting on a
pin r, and moving another lever S, S, by means of a pin
and a notch #, which acts on another pin at u ; and by
means of the two pins at AV it moves the knife lengthwise to
and fro : as fast as the skin is cut the barrel is drawn round
by the weight X. 3/ is a guide to the lever, from which end
it is worked.

VI.

A Memoir on Sulphuric Acid; hy Mr^ Klaproth : read at
the Philomathic Society of Berlin *.

A HE object of the author was to ascertain the respective Proportions of

^quantities of the elements of sulphuric acid and of sulphate ^^^ elements of
^ ^ ^ sulphuric acid

ot barytes, and he mentions the analyses that have been according to

made of these substances by the chemists whose names are^^"^"^^"^^*****

nubjoined:

Sulphuric acid consists,

Sulphur.

Oxigen,

according to Lavoisier, of

69

31

Berthollet

72

28

Thenard .

55-56

44-44

Chenevix

51-5

38-5

TrommsdorfT

70

30

Richter

42-05

57-95

Bucholz

42-5

57-5

* Abridged from the German by Mr. Bergman. Anpahs 4t
^Chime, Vol. JLVIII, p. 122, May, 180S.

330 rRiNCiri^ES. OF ^ulpiiuHic acid.

Qr^« |a»t tvro, though cakulated in different wajiS^, co^^
neatPQst to e^ch othw> ?Nnd thtypefore deserve raqst confidj^n^f .
l>ii<; iVir. Klaproth conceived It necessary to satisfy hiuj^t'if
by his own cxperirnents of the respective quantities of ti*e
elements of sulphuric acid, that he ««i§ht afterward apply
the results with more certainty to the analysis of pyrites or
metallic sulphurets. For this pdr|>ose he employed, as
other chemists had done, nitric acid and carbonate of bary-
l^oportion of tes ; the elements of tiiis salt-having previously been aseer-
the elements of taioted by him to ho. biu yfces -78, carbojtie acid -2^,

sulphate of -^ j f

barytes. Mr. BuchoJz, hovve\er having since asserted, that this

salt consists of "79 barytes, ajid 'tX carbonic acid, Mr.
Klaproth repeated/ his analysis wit4i 9JU possible care, and
still obtained the same proportions m before. We may here
add, that ^Mr. Buchol? admits OTvly '%6 of acid in the car-
bonate of strontian., while Mr. Klaproth has found "30 in
all the analyses he has made of this substance.

The results of the analysis of the sulphate of barytes
made by various chemists do not ditfer less than the propor-
tions they have assigned to the constituent principles of sul-
phuric acid. It is composed,

Barytes. Sulphuric acid.
■Given diflFer- According to Fourcroy, of - 66 34

ently by differ- Clement and Dcsormes 67-82 32*18

tut authors.

Thenard

Chencvix
Kirwan
Richtcr
Bucholz

.Kirwan's-prc- If indeed we except the analyses of Chenevix and Thenard,

fcfred byKIap-^l^g j.^^^ do not vary greatly from each other; and if we

ta^^e a mean of t\(^s>e^ Kirwan's cosies nearest to it, which

has induced Mr. Klaproth to adopt it as the most accurate.

rroccss for de- Proceeding on these data, the followbig was the method

cidiugtheques-^^^p^g^ by Mr. Klaproth. He introduced 200 grains of

pure sulphur, and eight ounces of pure nitric acid, of the

(Specific gravity of 1*32, into a retort, and distilled till about

three fourths had passed over into the receiver. The pro*

duct of this distillation was returned into ^e retort, and

distilled a second time. Eight ounces more of acid wer«

then added, and the whole distilled agaiu.

The

74-82

25-lS

76-5

23-5

67

33

69

31

67

33

JRlNCIPLfiS OF «tTtriItfRIC ACID. 531

The nnlinrnecl sulpliiir was fdtirid to weigh 48 grains and
lialf; consequently 15 If were converted into sulphuric acid.
The product diluted in a certain quantity of water was min-
gled with mnriate of barytcs, till no more precipitate was
produced. The sulphate of barytes, well wiiifhed and dried,
weighed 1109 grains; but, calcined in a platina crucible, its
weight was reduced to 1082 grains.

To 'find the proportions of the constituent principles of
concrete sulphuric acid, Mr. Klaproth took a hundred
grains of highly concentrated sulphuric acid,, the -specific
gravity of which was 1*85: this he diluted with fifteen parts
of water, and added to it muriate of barytes, till no more
precipitate was formed. The sulphate of barytcs, carefully
washed and dried, weighed 225 grains. Hence it follows: I'loportions of
1st, that 100 parts of sulphuric acid of the specific gravity Sd'.Sru*
of 1*85 are composed of ric acid :

Concrete sulphuric acid 74*4 or, sulphur 31*5
Water - - 25-6 oxigen 42-9

water 25-6

100

2dly, That 100 parts of concrete acid are formed of sul- of concrete
phur 42-3, oxigen bl'l, ''^^^ '■

3dly, That 100 parts of calcined sulphate of barytes and of sulphate
contain barytes ^7^^ sulphur 14, oxigen 19. ^^ barytes.

SCIENTIFIC NEJVS, S(c,

A Clasmjication of Ves^etahlef^^ and Plan of a new Method

formed on that of Tournefort, according to which the

Plants of the Garden of the private School of Pharmacy/

ut Paris are arranged: bi/ D. L. Gu yart, Assistant

Professor of Botany at the School, Sfc. •»

If, among the different botanical methods, that of Tour- Tournefort's
nefort has always been considered as the most easy, and best*^'^'*^^*^^*^^°^^^
calculated to guide the first steps of those who would study
plants; it must also be confessed, that it is insufficiertt,
when we endeavour to obtain an accurate idea of vegetable
organization. For this reason, no doubt, the methods of
Linneus and Juspieu are at present preferred, and almost
jfinivarsally adopted by botanists.

It

S52

Improvement
•f his method.

M. Guyares

arrangement.

Useful to be-
t^inners and
those who wish
for a general
knowledge
merely.

fCIENTIflC NEWS.

It is of importance, however, that Tournefort*s should
not be lost, as well on account of the celebrity of its author^
as for the utility of which it may still prove to young stu*
dents. By these motives Mr. Guyart has been induced to
compose a new classification of vegetables, founded on the
method of Tournefort; but in which, availing himself of
the progress subsequently made in the science of botany, he
has formed his classes from more striking and constant cha-
racters than those adopted by Tournefort. Thus he has
given fresh youth to the method of that botanist, and ren^
dered it more natural.

Tournefort's new method, as proposed by Mr, Guyart,
consists of sixteen classes. The first eight are formed of
plants with complete simple flowers. The first containing
the monopetalous : the second, the personate: the third,
the labiate: the fourth, the cruciform: the fifth, the rosa-,
ceous : the sixth, the umbelliferous : the seventh, the cary-
ophyllaceous : the eighth, the Icguniinous. The next three
include the plants with complete compound flowers, with
united anthers : the semifloscular, the floscular, and the ra-
diate. The four following are appropriated to the distinct
incomplete flowers: the apetalous, the amentaceous, the
glumaceous, and the liliaceous. The sixteenth and last is
assigned to the anomalous plants, or those with indistinct
incomplete flowers.

This classification, as the author observes, is not free
from defects ; but, notwithstanding its imperfections, al-
most unavoidable, perhaps, in such an undertaking, in the
opinion of some botanists of celebrity, whom he has con-
sulted, it will much facilitate the study to beginners, and is
still better adapted to those, who, not having time to cul-
tivate the science to its full extent, require only an acquaint,
ance with its elements.

INDEX'

INDEX.

Absorption of gases by water, 123

^cadcmy of Sciences at Petersburgh ;
adjudication of prizes, and new ques-
tion by, 70— at Munich, new orga-
nization of, 156— History and anti-
quities at Naples, 157

Acclimation of tender plants, 187

Accum, Mr. his lectures in chemistry,
80— His « System of Mineralogy and
Mineralogical Chemistry," 160

Acid, fluoric, in teeth and bones, 75—
njuriatic, production of by galvanism,
155 — Acetic, its action on alcohol,
185— Memoir oil, 315— Acetic prin-
ciples of, 349

Acid« produce prismatic colours on
polished steel, 125

Acoustics, 310

Adams's " Essays on tlie Microscope,'*
264

Air engine, 260

Aix la Chapelle, waters of, contain sul-
phuretted nitrogen gas, 41

Alcohol, how affected by metallic mu-
riates, oxigenized muriatic acid and
acetic acid, 183

Aletes on some difficiilties which orcnr
in the investigation of the capillary
action of fluids, 1, 2 50

Allaire, M. his new method of scower-
ing wool, 78

Alum, comparison of different kinds of,
275 — Analysis of, 278— Experiments
vith dyes, 282

Alnm works, history of, 275

Amand, St. baths of, 42

Animation, suspended, 254, 266

Apples, hints for the improvement of,
192

voL.xvm.

Ap«ophu5 on the structure of corered

ways, independent of the prhiciple of

the arch in equilibrium, and on the

best forms of arches in buildings, 241

Arabic, gum, solution of, examined,

28, 37
Arch, ancient substitute for, 241
Arches in buildings, best forms of, 249
Argand, Mr. A. his valve syphon de-
scribed, 61— His lamps with blue glaif
chimneys, 78
Arrago, M. on the refractive power cff

bodies, 27
Asparagus grows well in sand, 19
Attraction and repulsion, 2, 8
Auvergne, geological tour in, 295

6.

Baconla, Dr. his newly indented vege-
table galvanic pile, 159 ' *

Baker, Mr. his experiments on smutted
and mildewed corn, 264 ^

Banks, Sir J. on the proper mode of
inuring tender plants to the climate of
England, 187

Barometer, chamber, 81

Barometrical observations on the heights
of various places in France, &c. 210,
295 ' •

Barthelemy, M. on the Saero Catino of
Genoa, 97

Barytic salts, see Salts.

Basse, M. on sulphurous mineral waters,
42 — His mode of forming muriatic
ether, 182

Bavarian Academy of Sciences, &c*
156

Bevger, Dr. F. experiments by, on the

heights of various places, determined

by the barometer, in the course of

b fereral

INDEX.

several tours through France, Swis-

serland, and Italy, 210, 295

Bergman, a mistake of, detected, 276

BerthoUet, M. 182 — Letter to, on the

absorption of gases by water, by M.

Biot, 12.3 — His experiments on rays

of light and prismatic colours, 13 1—

His fulminating compound of silver,

140 — Oil nitrous ether, 144 — On the

action of oxigenized muriatic acid on

alcohol, 180 — On iron spar, 315-—

Letter to on various chemical actions,

by Mr. Haussmann, 339

BerthoUet, jun. on. the reciprocal action

of charcoal and sulphur, 43 — His ex-

. periraents on different alums in dyes,

234
Benelius, M. on fluoric acid contained
in the enamel of teeth and in bones,
75— Question by, respecting yttrium,
77
Biot, M. on the refractive power of
bodies, 27 — Extract of a letter from
to Mr. BerthoUet, on the absorption
of gases by water, 123— His " Phy-
sical Astronomy," extract from, 296
Blight in corn, its causes, and method

of prevention, 262
Bones, existence of fluoric acid in, 75
Borage, distilled yrater of, observations

on, 343
Bostock, Dr. J. on vegetable mucilages,

28
Botany, prize questions in, for 1807, by

the Academy of Petersburgh, 74
Boudet, jun. on the formation of phos-
phoric ether, 64
Bouesnel, M. 66
Bouillon Lagrange on grease, &c. 105—

On alumj 275
BouUay, M. 183-^His mode of making
phosphoric ether by means of a pe-
culiar apparatus, 6Q
Boyle, 16

Braconnet, Mr. H. his inquiries con-
(rerning the assimilating power in ve-
y. getables, 15 — On the Phytolacca^, or
' American pokeweed, 85

Brande, Mr. reference to his letter in
vol. xiii. on the non-existence of
fluoric acid in teeth and bones, 75
Bryant, Mr. on sea kale, 100
Buch, Mr. Von, his geological tour in

Auvergne, 295
Bucholz, M. his analysis of a pretended

pure native magnesia, 236, 320
Burnt wheat, a disease in corn, 265
Busts, ancient, made by American In-
dians, 158

C.
Capillary action of fluids, 1, 250
Carbon in sulphurous waters, 41
Carlisle, Mr. his lectures on surgery and

physiology, 2^0
Cayley, Sir G. his engine for affording
mechanical power from air expanded
by heat, described, 260
Cerasin, a distinct principle peculiar to

cherry gum, 39
Cerium and iron formed into an alloy,

77
Chance, table for the calculation of, 117
Chaptal, M. 182 — On paring and burn-
ing land, 22— His correction of a mi,s-
take of Bergman, 276
Charcoal and sulphur, reciprocal action

of, 43
Charcoal of marze, 339
Chemical actions, 339
Chemistry, Mr, Accum's lectures in,

m

Chemists, Dutch, their hypothesis er-
roneous respecting nitrous ether, 147

Cherry-tree gum, examination of, 29,
39

Chessy, mines of, 51

Classification of insects, 218

Clement, M. his experiments on car-
binetted sulphur, 4S

Clover, improvement in the cultiva-
tion of, 271

Coal, see Pitcoal.— -pToductS ©f difft-rent
kinds, 162

Colours, prismaticof thin }>eHJcIes, 128

Canclamine, M. his opinion of the Sacro
Catitio of Gcnor.; 97

Cop^ir

INDEX.

Copper, pyrltous, account of the me-
tallurgic treatment of in the depart-
ment of the Rhone, 51
Copper, heated, displays piismatic lints,

135
Copper pyrites, effects of heat on, 20 1
Copper, desiilphu ration of, 208
tovereti ways of the ancients, 243
€rambe Maritimo, pr sea kale, cultiva-
tion of, 100
Crops, rotation of, a n^w plan for, 273
Cruickshauk on the formation of water,

27
•urtis, Mr. his improvement in the
culture of sea kale, 100
D.
D'Arcet, M. on the decomposition of
acetate of barytes, by means of soda,
66
Dalton, Mr. 315
DaviUiers, M.284

Davy, Humphry, Esq. on some chemi-
cal agencies of electricity, 32 1
Danbuisson, M. his observations on
subterranean heat, made in the mines
of Poullaouen and Huelgout, in Brit-
tany, 148
Death from cold, investigation of, 2!j4i
becroissilles, M. 276
Delametherie, M. on the oxidation of
the solder of leaden vessels used in
wash-houses, 115— Letter to, on the
production of muriatic acid by givlva-
nism, 153
Degeer, 218
Delft earthenware, its defects, and a

substitute proposed, 292
Densidoif, M. Procopius, his method

of germinating seeds, 15
Descotils, M. his experiments on cu-
preous pyrites, 51— His account of a
fulminating compound of s.lver, 140
*— On spar, 315
Desormes, on carburetted sulphur, 43
Desulphuration of metals, 197
Detonating silver, 140
Deyeux, M. 182 •—On the reciprocal
action of r^^lphur and chaiceal, 43

Diamonds contain hydrogen, 27
Disoxiding principle in distilled waters,

343
Donovan, Mr. his musaum, 121
Dubuat, M. his hydraulic theorertt

transformed, 309
Duck's wing, colours of, how produced,

138
Ducloseau, M. on ascertaining the

quality of window glass, 143
Dnhamel, 15

Duncan, Dr. his opinion on the preci-
pitation of tragacanth by sulphate of

copper, controverted, 31
Du Pont, Mr. De Nemours, on a kind

of death that may be presumed to be

only apparent^ 254
Diitens, M. a mistake of respecting a

stone, which he describes as a varietf

of the Peruvian emerald,
Dyes, experiments with, 2^2

E.

Ear-cockie in wheat, 265

Ear trumpets, theory of, 310

Earthenware, history of, 291— Fact for
proving the quality of its glaze, 294

Earth, solubility of, by means of sugar,
9

Eckeberg, Mr. his comparison of bary-
tes, yttria, and magnesia, 77

Eels, remarkable account of a migra-
tion of, 236

Eilsen, baths of, 42

Electric spark, query respecting, 123

Electricity, 271, 321

Electrometer, a portable, described,
270

Emeralds, the largest known, 99

Encrinites, British nondescript, 121

Ether, phosphoric, apparatus for making,
63

Ether, nitrous, report on a paper on,
144

Ether, muriatic, memoir on, 176 — Ap-
paratus for obtaining, described^ ib.

Evaporation, 9

Expansion of air by heat, 260

b2 Wi

I N tf^Xl

I.

Fabricluf, 218

^aWun, description of the smelting
furnace there, 202

Fire-damps in coal pits, 155

Flints, formation of, 114— Analysis of,
115

Flour paste, experiments on, 54

Fluids, resistance of, prize question on,
by the Petersburgh Academy, and
answers, 72

Fluoric acid in teeth and bones, 75

Folkes, M. Esq. 264

Fossil shells in America, 159

Fougeray de Laurmi, M 115

Fourcroy, M. 23, 182— On the action
bf sulphur on charcoal, 4-3

Fourmi, his invention of a porcelain
capable of bearing the action of fire,
293

France, geological tour through part of,
212

Fremy, M . his observations on the com-
bination of fixed oils with the oxides
of lead, and with alkalis,. 231

Fruits, new and early, method of pro-
ducing, 189

Fulminating compound of silver, 140

Furnance at Fahlun, in Sweden, de-
scribed, 202

Gahn, Mr. his alloy of cerium and
iron, 77

Galena, e^Tects of heat on, 202, 209

Galvanic pile of vegetabk subs lance?,
159

Galvanism, 155

Gases, absorption of by water, 123—
Produced by nitrous ether, 145

Gay Lussac, M. 182— On the absorp-
tion of gases by water, 125— On eu-
diometry, 126— On the glaze of com-
nroa pottery, 29Z

Gchlen, M. oii the existcnct of i\wn&
acid in teeth and bones, 75— His dis-
covery of muriatic ether, 1^2

Gems, artificial, method of det«cting,
99

Geneva, Lake of, brief description of
several mountains in its neighboiu-*
hood, 301

Genoa, account of the antique vessel
there called Sacro Catinoy 97

Geoffrey, 218

Geological observations in France, &c.
210, 295

Geometrical instruments, improve<^
219

Gimbernat, Dr. on the waters of Aix
la Chapelle, 41

Giobert, M. on magnesian earth, 293

Glassy coloured, of remote invention,.
99

Glass, means of ascertaining the qua*
Kty of, 142

Glass obtained from aitificial feldt spar,
294

Glaze of earthenware defective and per-
nicious, 292— Test fur proving the
quality of, 294

Gluten of flour paste, experiments on,
34, 37

Gough, J. Esq. his description of it
correct chamber barometer, 81— *On
the theory of ear trun)peti?, 310—
Correction of a mistake respecting \.\\q.
degree of cold at which water may
retain its fluidity, 315

Gold, colours produced by when heat-»
ed, 135

Gooseberry jelly, experiments on, 34

Gravesande, M. his experiments on in •
flexiony 131

Grapesy hints on the improvement of
the growth of, 194

Grease, medicinal compounds made
with it, 105

Gueniveau, M. his account of the me-

tallurgic treatment of pyritons copper

at the mines of Chessy and Sainbel,

in the department of the Rhone, 31

^Oa

INDEX.

- €— On tlie desulphuration of metals,

197
Gums, see Arabic, cherry -tree, traga-

canth, «&c.— General characters and
species, 38
Gunpowder prober, 62
Cuyart, M. his new classification of

plants, 351
Guyton, M. his account of the antique
vessel that was preserved at Genoa,
under the name of Sacro Catino, and
, reputed to be an emerald, 97— On
the means of forming a judgment on
the quality of glass, particularly win-
dow glass, and distiiiguishing such as
is liable to alteration, 142— On ni-
trous ether, 144— On conamon pot-
tery and porcelain, 291
H.
ilall, Rer. James, extracts from his

" Travels in Scotland, 236
Haquet, M. on the formation of flint,

114 '

Uarrup, Mr, on the diseases of wheat,

2G2
Hassenfratz's experiments on'rogetatlon,
25, 27 — On copper pyrites, 51— On
sparry iron ores, S16
Haussmaiin, M. on various chemical

action*;, 339
Hauy, 98

Hearing trumpets, 310
Heat, subterranean, 148— Action of on

metallic sulphurets, 108
Heinrich, Mr. his prize essay on light,

72
Helmont, Van, his experiment on ve-
getable nutrition, 1 5
Hoegemuller, Chevalier Von, his in-
. tended tour to the East, 158
Romberg on vegetation, 25
Howard, Mr. his fulminating mercury,

140
Hubert, M. on vegetation, 23
Humboldt, Von, on plants growing in
deep mines, 26— On the absorption
of gases by water, i:,'^>'— On audiome-
try, 126

Huygens's experiments on vegetation, S4
Hyacinth roots, mucilage of, its proper

ties, 52, 38
Hydraulics, 309
Hydrophilus, on the doctrine of chancfeg,

116 — ^An universal tide table by, 118

—Remarks on the breaking of the

waves, ib
Hygiocerames, a species of porcelain,

capable of standing the hfe, 293

I.

Indian corn, facts respecting, 239
Indigestion caused by the formation of

acetous acid, 66
Iron pyrites, effects of heat on, 2QI
Iron spar, 315
Insects, new classification of, 213

J.

Jefferson, Mr. president of the United
States of America, his collection oi
Indian busts, 158

Jellies, vegetable, experiments on, 34

Joussclin, M. his " essays on the im-
provement of pottery in general, or
the art of making at the least expence
vessels for every use, more handsom^
strong, and wholesome, without em-
ploying lead or tin in the composi-
tion of the coating, enamel, or glaze,'*
abridged, 201

Juan, Don George, his theory of the
resistance of flui<ls, 72

Jurine, Professor, his new method of
classing the hymenopterous and dip-
terous insects, 218— His geological
tourinAuvejgne, 295

Kenmacher, on the cause of the bli|;ht

in wheat, 264
Kirwan, Mr. 293 — On combiriations of

sulphur and hidrogen, 45 v^

Klaproth, M. on sulphuric acid, o49
Knight, T. A. Esq. on the method q£

pfoducint? new and earlv fruits, 18^

u

INDEX.

L.

la!ande, M- 75
Lambert, M. 293

lAinpadius, Professor, his experiments
,. , on siilphqi" and charcoal, 43
Lamps, witix blue glass or spar chim-
neys, 78
JLaplace's doctrine of capillary action,

defective, 1, 7, 250
l^arum for a watch, 228
LareUle, 218

Latoisier, on the combustion of char-
coat, 27— His unsuccessful attempt
at making phosphoric ether, 63
Lauragais's experiment on stoneware,

20S
Laurent, Rev. Mr. on sea kale, 101
Lead solder, s^S solder.
Lead, bro^Tn oxide of, inflames sulphur
by trituration, 71 — melted exhibits
prismatic colours in cooUng, 1S5
Lelievre, M. on iron spar, yi5
Lemairc, M. on cupreous pyrites, 56
Leybourn, Mr. T. his " Mathemaiical

Repository," lo9
Library at Munich, 157
Life, animal suspension of, 254,266
Light, $»e colours.

Light, question on, proposed by the
Petersburgh Academy of Sciences,
and answers, 70
Lt^ht and hidrogen, probablUty of their
being analogous in regard to vegeta-
tion, 26
Lime proved to be volatile, 22
Link, Professor, his prize essay on light,

72
Linnasus, 218
Linseed, mucilage of, experiments on,

01, 37
Luc, M. 'de, on the calculation of

heights, 211
Lunar teble, 100
l.ycopodium, analysis of, 320

M.

Maeltz, M, his mechanical imitating

various v.ind instrmnents and oth«r»i|
157
Magnesia, pretended native, 235
Magpie, singular economy of, 238
Maher, Mr. on the cultivation of the
crambo maritima of Linnaeus, or sea
kale, 100
Maize, facts respecting, 239
Manure, how fur useful to vegetation,

16
Marty, Mr. Do, on absorption of gases
by water, 123, 125, &c.— On eu-
diometry,Nl26
Marty n. Professor, on sea kale, 101
" Mathematical Repository," 159
Medical and chemical lectures at St.

George's Hospital 160
Murcury, desulphuration of, 208— •

Fulminating compound of, 140
Merriweather, General D. on the ridges

of shells fovind in America, 158
Metals, desulphuration of, 197
Miller, Mr. P. on sea kale, 100
Mineral waters containing sulphur>

analysis of, 40
Mitchell, Dr. letter to, 158
MittenJjof, M. 296
Moss used to promote the germination

of seeds, 15
Mould, vegetable, analysed, 16
Mucilages, vegetable, 2B, 38
Mucus, generic characters and specie*

of, 38
Munich, its Academy of Sciences, Li-
brary, and Gallery of Paintings, 147
Muriatic acid, see acid.
Muriatic ether, see ether.
Muriate", metallic, their action on al-
cohol, 183
Mustard seed, experiments on th#
grow I h of, 17

N.

Naples, institution of a Royal Academy

of history und antiquities at, 157
Napolean Museum, 157

Natural

INDEX.

Natural history, some i:«markable oc-
currences in, 236

Natural philosophy, see Philosophy.

Is'eedham, Mr. his discovery of auimal-
culae in diseased corn, 264

Nenndorf, in Hesse, waters of, contain
sulphuretted nitrogen ga-s^ 41

Newton, Sir Isaac, on colours, 129,
267

Nordmark, Professor, his prize essay on
the resistance of fluids, 72

Nutrition of vegetables, \b

O,

Oil, vessel fot preservuig free from co-
agulation, 79

Oils, fixed, cdrabiuation of with oxides
of lead and with alkalies, 231

Olbers, M. his discovery of a new
planet, 75

O. N.'s description of a simple and con-
venient portable electfometer for mi-
neralogistis, 270

P.

Paring and burning land, examination
of its effects and their cat^ses, 21

Pajot la Foret, M. 142

Parkinson's description of the sea kale
erroneous, 100 — On British encrintes,
121

farmentier, M. his opinion of the uses
of manure, 17

Peaches, improvement in the manage-
ment of, 195

Peacock's feathers, .summary consider-
ations on the colours of, 137

Pearson, Dr. his medical and chemical
lectures, 160

Perperrcs, M. on the causes of indiges-
tion, 66

Petersburgh, Academy of SdeHces at,
j^vQceedings of, 70

Philosophy, naturat, Dr. ToTing'f Te^
tures in, 79

Phosphoric ether, see ether. '

Physiology, lectures on, 160

Phytolacca, or American pokeweel,
85

Pigeon's neck, colours of, how producei|
138

Pitcoal, facts towards a history of, 161

Place, La, on determining heights by-
means of the barometer, 210

Planet, new, discovered by M. OJbeis,
75

Plants produced by means of air and
water only, contain less carbon than
their seeds, 15— Analysis of, 18

Plants 1 tender, hints respecting the pro-
per mode of inuring them to the cli-
mate of England, 187

Plasters and soaps, 231

Porcelain, improvements in the fabrica-
tion of, 293

Potatoes grow best in sand, 19

Pottery, improvement of, 291

Priestly, Dr. 24

Prienr, M. on the prismatic colours of
bodies reduced to thin pellicles, with
an explanation of the colours of an-
i^ealed steel, and those of a pea-
cock's feathers, 128

Prior, Mr. description of his larum for
pocket watches, 228

Prismatic colours, see colours.

Proteus Anguinus, description of, 91

Proust, Professor, 77, 182— His expe-
riments on alcohol and lime, 23—
Memoir on the glaze of earthenware
incorrect, 292 — On pitcoal, 1 Gl— On
Indian corn, 239

Pyrita^, copper and iron, effects of heat
on, 51, 201

Quadrant and Stafti Mr. I^almon^s, de-
scribeil, 227

Que;iPR*li

INDEX.

<ft«««i*s eafH^enware, its defects, and a

substitute proposed, 292
Quicksilver fro«en and beaten into a

thin plate, 159
Quinceseed, mucilage of, experiments

on, 31

R.

lUdish seed, experiments on the growth

«f, 18

Ramsay, Mr. W. on the solubility of
earths by means of sugar, 9

R. B. letter from, containing an in-
quiry respecting a fact not hitherto
noticed in the way of discussion,
122

Regnier, Mr. his instrument for proving
the strength of gunpowder, described,
€$?

Repulsion, see Attraction.

Ridges of shells in America, 158

E},ffault, M. 183

Roard, M. on Roman alum, 275

Rt>biquet, M. bis experiments on the
action of sulphur on charcoal, 50

Rome's theory of the re;,istance of fluids,
72

Rotation of crops, a new, 273

S.
Sacro Catino of Genoa, described, 97
Satnbcl, mines of, 51
Salmon, Mr. description and manner of
using his geometrical plotting qua-
drant, level, and calculator, for the
use of navigation, and land-survey-
ing, ascertaining inaccessible dis-
tances, and demonstrating and de-
termining various problems in geo-
metry and trigonometry, 219
Salts, barytic, decomposed by nitric, 66
Saussure, M. Von, his experiment on
the uses of carbonic acid to vegeta-
tion, 22, 24— His tour to the Alps,
296
Schaub, '^"^ on the waters of Nenndorf,

in Hesse, 41
Scheele, M. 2o2— On combinations of
sulphur and hydrogen, 45— Notice
isi his unsuccessful attempts to trans-

form alcohol into ether, 63— Cor*
rection of a mistake of his, respect-
ing muriatic ether, 184
Schlumberger, M. 277
Schreiber, M. on the natural history ©f

the Proteus Anguinis, 93
Scientiac News, 70, 55, 320, 351
Sea kale, cultivation of, 100
Sediment of water, arrangement of*

122
Seeds most difficult to germinate, suc-
ceed in Moss, 15
Sennebier, on the decomposition and
absorption of atmospheric carbonic
acid by vegetables, 22, 23
Shell's extensive ridges of, in America*

158
Siauve, M. 91

Silver, detonating compoimd of , 1 40
Siphon, Mr. Argand's, described, 61
Skins, machine for splitting, 348
Smelting, furnace at Fahlun, in Swe-
den, 202
Smith, Dr on the cultivation of sea

kale, 100
Smut in wheat, its causes and method

of preservation, 263
Soaps and plasters, 231
Solder of leaden vessels. Oxidation of,

115
Solubility of earths, by means of su-
gar, 9
Spark, electric, its various appear-
ances, 123
Sparry, iron ores, 315
Starch, mucilage of, examined, 23, 37
Steel, annealed, considerations on tha

colours, of, 134
Steinacher, M. on the distilled water of

common borage, 343
Stoneware proposed as a substitute for

all glazed earthenware, 293
Stott, Mr. account of his engine for

splitting sheep skins, 348
Strawberries, their varieties, 197
Sugar, Experiments on, 10
Sugar, mucilage of, examination of its
properties, 34

2 Sulphuf

INDEX.

gulpliur, action of, on cUarcoal, 43—
inflamed by* oxide of lead, 77

Sulphurets metallic, how affected by
the action of heat, 198, 202

Sulphurous mineral waters, 40

Surgery, lectures on, 160

Sylvester, Mr. a 520

Tables of heights above the level of

the sea in France, 217, 299
Tan mixed with mucilage of staich, 53
Teeth, fluoric acid in the enamel and

bones of, 75
Tests, of vegetable mucilages, and

jellies, 35
Thenard, M. on nitrous ether, 144 —
abstract of his memoir on the mu-
riatic ether, 176— 'Observations on its
discovery, 182 — Abstracts of his me-
moir on the products that result
from the action of metallic muriates,
oxigenized muiiatic acid, and acetic
acid, on alcohol, 183, see also 320
Thenard and Roard, their memoirs on
Roman alum, compared with differ'
ent kinds manufactured in France
275
Thomson, Dr. his experiments on the
mucilage of cherry-tree gum, 29,
35 — On the effects produced by an
infusion of tan in the mucilage of
starch, S3— Comment on his paper
in the oxides of lead (inserted vol.
viii.) 77
« Thomson's Chemistry," 183
Tide table, an imiversal, 118, 119
Tiilet's experiments on vegetation,

15 — On manure, 17.
Tin, heated, produced prismatic colours,

135
Tour to the East, intended, 158
Tour through Picardy and Normandy,

212 — In Auveigne, 295
Tournefort's classification of plants, 351
Tragacanth, gum, examination of its
pr©penies, 30, 39

Trembley, M. on the calculatitn of ijji
titudes, 211

Tremery, M. 131

Trigonometry, use of, 2W

Trommpdorff, M. on aaetic acid, 345

Turf, analysis of, 175

Tyro, questions by, on some appear-
ances of the electric sparky 123

Valve Siphon, description of, 61

Vapours injurious to vegetation, 22

Vauquelin, M. 182 — On the action of
Sulphur on charcoal, 43, 50— On
the exides of lead, 77 — On tht
Sacro Catino of Genoa. 98 — On ni-
trous ether, 144 — On the solder of
leaden vessels used by laundresses,
115 — His analysis of alum, 276—
On iron spar, 315

Veau de Launay, Dr. on the produc-
tion of oxigenized muriatic acid by
the galvanic pile, 155

Vegetable mucilages, 28 — ^Jellies, 34

Vegetables, nutrition of, 15

Vincent, M. De, his method of sowing
clover, and a new plan for a rotation
of crops, 271

Vogel, M. on grease and some medici-
nal compoimds of which ii is the
basis, 105

U

Urine, presence of fluoric acid in, 7^
Utschneider, M: 293

W.

Water, inquiry relative to the arrange-
ment of its sediment, 122

Water, sulphurous mineral, examined,
40

Waves, remarks on the breaking of, 1 18

Westrumb, M. on sulphurous mineral
waters, 40

Wheat, diseases of, 262

Wind instruments, mechanical imita-

tation of, 157

%Vitit«rl,

I J^ D feX.

1

Wiaterl, Mr. on the existence of hy-
drogen in diamonds, 27
Withering, Mr. on sea kale, 100
W. N. on an universal tide table, 119
Woodward, Mr, on sea kale, 100
Wool, new pro<Sess for scowering, 78

Y.

Young) Dr. T. lamination of his rea^ i

soning on the capillary action of
fluids, 1, 4— Notice of his lectures ia
natural philosophy, 79 — On the hy-
draulic theorem of Dubicat, 309
Yttria, oxigenizes muriatic acid, 77

Z.

Zois, Baron Von, his memoir ©n t)i«
Proteus Anguinis, 91

END OP THJ: CICHTEENTH VOLUMEr

JfrJmed by W. Stratford, Crown-Covrt, Temi>lc-i5.^r.