si^r

JOURNAL

or

NATURAL PHILOSOPHY,
CHEMISTRY,

AND

THE ARTS.

VOL. XIX.

3jllustratetJ tottf) <£ngtat)tng&.

BY WILLIAM NICHOLSON

sc

LONDON:

PRINTED BY W. STRATFORD, CROWN COURT, TEMPLE BAR ; FOR

W. NICHOLSON,
CHARLOTTE STREET, BLOOMSBURY,

AND SOLD BY

J. STRATFORD, No. 112, Holborn-Hill.

1808.

«1 PREFACE.

HE Authors of Original Papers and Communications
in the present Volume are, Mr. Charles Sylvester ; J. S.
Traill, M. D. ; Mr. Richard Winter ; Philommatos ; A
Chemist; J. G. C; William Henry, M. D.; Thomas
Thomson, M. D. F. R. S. E.; Mr. William Skrimshire,
Jun.; John Gough Esq.; G. S. Gibbes, M. D.;
N. R. D.; Joseph Reade, M. D ; Mr. Donovan; Mr.
Barraud; Dytiscus; J. Garnett, Esq.; The Rev, T.
Vince, Professor of Astronomy at Cambridge ; and Fre-
derick Stromeyer, M. D. Professor at Gottingen.

Of Foreign Works, M. La Lande ; J. Carradori de
Prato, M. D.; M. Decandolle; M. Trommsdorff ; M.
Bernhardi; M. Robiquet; M. Chevreul; M. C. A. Cadet;
M. Vauquelin; M. Boullay; M. Hisinger; M. Berzelius;
M. Thenard; Dr. Berger; Mr. Adolphus Ledhuy.

And of British Memoirs abridged or extracted, Mr.
Davis; Humphry Davy, Esq. F. R. S. M. R. I. A.; Wil-
liam Hasledine Pepys, Esq.; Right Hon. Sir Joseph
Banks, Bart, Tv. B. P. R. S. &c; Thomas Andrew Knight,
Esq. F. R, S. ; Everard Home, Esq. F. R. S; William
Herschell, L. L. D. F. R. S. ; William Allen, Esq. F. L. S. ;
John Jerome Schroeter, F. R. S.; Mr. Lewi n Tug well;
Dr. Cogan; Mr. Robert Hallett; Brigade Major William
Lambton; C. H. Parry, M. D.; T. Davis, Esq.; W.
Matthews, Esq.; Dr. Anderson; Mr. Edward Martin;
W, H. Wollaston, M. D.; and W. Roxburge, M. D.

The Engravings consist of 1. Guide to the Constella-
tions; 2. Mr. Davis's Machine for Glaziers; 3. Mr. Davy's
Experiments oq Galvanism; 4. New Eudiometer by W.
H. Pepys, Esq.; 5. Experiments on inflected Light, by
Mr. R. Winter; 6 and 7. Dr. Hershell on coloured con-
centric Rings; 8. Dr. Joseph Reade's Calorimeter; 9.
Messrs. Allen and Pepys on Carbonic Acid, and the
Diamond; 10. Mr. Barraud's Mercurial Pendulum; 11.
Dr. Hershell on the Planet Vesta; 12. Mr. Tugwell's
new Method of Roofing Houses; 13. Representation of a
Mineral Bason in South Wales.

TABLE

TABLt .OF CONTENTS

TO THIS NINETEENTH VOLUME. r>-

[ 1

ill

:ih

jaxuarv

-

Engravings of the following Objects: 1. Guide to. the Constellations: 2. Mr.
Machine for Glaziers: 3. Mr. Davy's Experiments. on Galvanism!

* A . 1 .( . ■.'- ,n<

I. An Account of the relative Situations of the different Stars; ( by whjcja the
principal Constellations mav be distinguished. From la Lande's'Astrbnomv,
third Edition, Art. 743, &p, - - - -; .d .Rge 1

II. On the Advantages of Malleable Zinc, aiid the Purposes to which1 it may be
applied. By Mr. Charles Sylvester - - ] i

III. Description of Mr Davis's improved Machine for Painters and Graders 13

IV. Answer to some Observations of Mr. Dispan on the pretended Attraction
of Surface between Oil and Water ; by J. Carjadori de Prato, Mr D." 14

V. Abstract of an Essay on the Medicinal Properties of Plants compared with
their external Form and natural Classifications : by Mr. Decandolie- 17

VI. Analysis of the Siderite, or Lazulite; by Messrs. Trommsdorff and Bern-
hardt - - - - - 20

VII. On the Preparation of 'pure Barytes; by Mr. Robiquet - 23

VIII. Remark on the spontaneous Decomposition of the hidroguretted Sul-
phuret of Bary tes : by Messrs. Robiquet and Chevreul - . 25

IX. Remark on a. Property of Camphorated Water: by C. A, Cadet, Apothe-
cary in ordinary to his Majesty - - - - 26

X. Report on a Memoir of Mr. Destouches, Apothecary at Paris ; by Messrs.
Vauquelin and Boullay. Read at the Parisian Society of Pharmacy, Fe-
bruary lo, 1807 - - - • - ' 2&

XT. Mineraiogica] Description and Chemical Analysis of a Stone, called Py-
rophysalite: by Messrs. Hisinger and BerzelLus - - 33

XII. On some Chemical Agencies of Electricity : by Humphrey Davy, Esq.
F. R. S. M. R. I. A. - - - - - 37

XIN. Memoir on the Analysis of the Sweat* the Acid it contains, and the Acids
of the Urine and Milk ; read to the National Institute by Mr. Thenard 03

XIV- Remarks on Orpirnent and Realgar: by Mr. Thenard - 74

Scientific News - - - - ' 78

FEBRUARY,

C O N T E N T S.

FEBRUARY, 1808.

Engravings of the following Objects: l.New Eudiometer, by W. H. Pepys,
Esq.: 2*. Experiments on infloctrel Liglit, by Mr. R. Winter: 3. Figures "to
illustrate the Formation of coloured concentric Rings,' by Dr. W. Herschel.

I. On Albinoes ; bv T. $. trauf, M. D. - 81

II, Description of a new Eudiometer, accompanied with Experiments, eluci-
dating its Application. By William Haslediue Pepys, Esq. Communicated
by Charles Hatchett, Esq. F. R. S. '-' ' - 80

111 On the Revival of ah obsolete Mode of managing Strawberries. By the
Right" Hon. Sir Joseph Banks, Bart, K. B. P. R. sY&c. - 95

IV. On raising new and early Varieties of the Potato (Solanum Tuberosum.)
By Thomas Andrew Knight, Esq. F. R. S. &c. - - 97

V. An Account of two Children bom with Cataracts in their Eyes, to show
that their Sight was obscured in very different Degrees ; with Experiments to
determine the proportional' Knowledge of Objects acquired by them imme-
diately ailer the Cataracts were removed. By Everard Home, Esq. F. R. S. 99

VI. Experiments on various Species of Cinchona : by Mr. Vauquelin 100

VJJ. Experiments for investigating the Cause of the coloured concentric Rings,
discovered bv Sir Isaac Newton, between two Object-glasses laid upon one
another. By William Herschel, LL.D. F. R. S. - - 121

VIJI. A Method of finding the Specific Gravity of Light from Analogy ; and
the undulatory Svstem defended by an Experiment on inflected Light. In a
Letter from Mr. kichard Winter - - - 143

IX. Account of an Accident from the sudden Deflagration of the Base of Potash.
In a Letter from a Correspondent - * * 146

X. Correction of some Misstatements in the Account of Mr. Davy's Decom-
position of the fixed Alkalis, in a Letter from a Correspondent " 147

XL An Improvement in the Galvanic Trough, to prevent the Cement from
being melted, when the Action is very powerful. Communicated by a Cor-
respondent - - - - - -148

XII. Experiments on the Fire-damp of Coal Mines, by William Henry, M. D.;
including a Communication on the Subject from Thomas Thomson, M. D.
F. R. S. E. Communicated by Dr. Henry - 14fli

XIII. On the Phosphorescence of Bodies, from the Action of the Electric Ex-
plosion. In a Letter from Mr. William Skrimshire, Jun. to Mr. John Cuth-
bertson --.___ 153

XIV. Experiments on the Decomposition of the fixed Alkalis by Galvanism.
In a Letter from Mr. Charles Sylvester - - - 156

Scientific News - • - * - 157

MARCH,

vi CONTENTS.

MARCH, 1808.

Engravings of the following Objects : 1. Figures to illustrate the Formation of
coloured concentric Rings, by Dr. W. Herschel : 2. Dr. Joseph Reade's Ca-
lorimeter: 3. Messrs: Allen and Pepys on Carbonic Acid, and the Diamond.

I. Remarks on Torpidity in Animals, in two Letters from John Gough, Esq. 161

II. On the Nonexistence of Oxigen and Hidrogen, as Bases of particular
Gasse> ; the Action of Galvanism ; and the compound Nature of the Matter
of Heat. In a Letter from G. S. Gibbes, M. D. - - 170

III. Letter from N. R. D., containing some Remarks and Emendations of his
Communication in the Number for January - - - 173

IV. On the Advantages of grafting Walnut, Mulberry, and Chesnut Trees.
By Thomas Andrew Knight, Esq. F.R.S. &c. - - 175

V. Experiments for investigating the Cause of the coloured concentric Rings*
discovered by Sir Isaac Newton, between two Object-glasses laid upon one
another. By Wiliiam Herschel, L.L. D. F. R. S. - 177

AT. Description of a newly-invented Calorimeter; with Experiments to prove,
that an increased Capacity for Caloric accompanies an Increase of Temper
rature. 'By Joseph Reade, M. D. - - 107

VII, Experiments on the various Species of Cinchona ; by M. Vauquelin 203

VI II. On the Quantity of Carbon in Carbonic Acid, and on the Nature of the
Diamond. By William Allen, Esq. F. L. S. and William Hasledine Pepys,
Es,q. Communicated by Humphry Davy, Esq. Secretary R. S. M. R. 1 A.

216

]yi. Account of an extinct Volcano in Britain. Communicated by Mr, Don-
ovan - - - - - 237

Scientific News - 24&

APRIL,

CONTENTS. vii

APRIL, 1808.

Engravings of the following Objects: 1. Mr. Barraud's Mercurial Pendulum:
2. Dr. Herschel on tUe Planet Vesta: 3. Mr. Tugwell's new Method of
Roofing Houses.

I. On the formation of the Bark of Trees. In a Letter from T. A. Knight, Esq.
F. R. S. to the Right Honourable Sir Joseph Banks, K. B. P. R. S. &c 2-H

II. On the Economy of Bees. In a Letter from Thomas Andrew Knight, Jmj.
F. R. S. to the Right Honourable Sir Joseph Banks, Bart. K. B. P. R. S. 250

III. Description of a Mercurial Pendulum. Communicated by Mr. Barraud, of
Cornhill, who has made several, and has been highly satisfied with their Per-
formance in the Measure af Time - - - < 258

IV. Observations on the Nature of the new celestial Body discovered by Dr.
Olbers, and of the Comet which was expected to appear last January in its
Return from the Sun. By William Herschel, LL.D. F. R. S. - 259

V. Observations and Measurements of the Planet Vesta. By John Jerome
Schroeter, F. R. S. - - - - 264

VI. On a new Method of Slating, and constructing the Roofs of Houses : by
Mr. Lewin Tugwell - - - 2Q0

VIL Heights of various Places in France, &c. ; by Dr. Berger. Concluded
from Vol. XVIII, p. 308 - !272

VIII. On the Cultivation of the Poppy. By T. Cogan, M. D. 282

IX. On the Use of Tobacco Water, in preserving Fruit Crops, by destroying
Insects : and on the Use of the Striped or Ribband Grass. By Mr. Robert
Hallett ------ 298

X. A second Letter from Mr. Robert Hallet, on the Efficacy of Tobacco Water
in destroying Insects, infesting Fruit Trees - - 301

XI. Remarks on a Pamphlet, lately publi xed by the Rev. S. Vince, respecting
the Cause of Gravitation. By a Corre pondent. - - 304

XII. Farther Experiments and Obse* .ations on Potash and its Base. In a
Letter from Mr. C. Sylvester - - - - 307

XIII. An Account of the Measurer^ jnt of an Arc on the Meridian on the Coast
of Coromandel, and the Leng*\ of a Degree deduced therefrom in the La-
titude 12° 32', By Brigade Ma :>r William Lambton - 309

Scientific News - * - - 317

SUPPLEMENT.

viii CONTENTS.

SUPPLEMENT TO VOL XIX.

iviijff of the following Object: Representation of a Mineral Basin in
south Wales.

I. Remarks ©n the total Eclipse of the Sun, June 16, 1806"; with some new
Methods of timling the Sun or Moon's Meridian Altitude, and the approximate
Time, by Altitudes taken near the Time of Noon. In a Letter from J. Garnett,
Esq. Editor of the American Nautical Almanack - - 321

II. An Inquiry into the Causes of the Decay of Wood, and the Means of pre-
venting it. "By C. II. Parry. M. D. 328

III. On the Blight in Wheat. By Mr. Thomas Davis, of Horningsham 338

IV. Answer to Remarks on a Pamphlet, lately published by the (Rev. T. Vince,
respecting the Cause of Gravitation. In a Letter from the Author 344

V. Observations on the Structure of the dii'ferent Cavities, which constitute >the
Stomach of the- Whale, compared with those of ruminating Ajrckmals, with a
View to ascertain the Situation of the digestive Organ, By Everard Home,
Esq. F..R. & - - - - 348

VI. On Family Wine Making. By W. Mathews, Esq. - 353

VII. Description of the"Mineral Bason, in the Counties of Monmouth, Glamor-
gan, Brecon, Carmarthen, and Pembroke. By ,Mr. Edward Martin. Com-
municated by the Right Hon. C. F. Grenvrlle, F. R. S. - - 361

VIII. On Fairy-Rings. By VV. H. Wollaston, M.D. Sec. R. 5. 3G7

IX. Account of a Musical Instrument, called an Organized Lyre, invented by
Mr. Adolphus Ledlurv, latv- Geometrical Surveyor of Forests, of Coucy-le-
Chateau, in the Department of the Aisne - - 371

X. A Botanical and Economical Account of Bassia Butyracea, or the East
India Butter Tree. By W. Roxburgh, M.D. - - 372

- ■

XI. Observations on Werner's Silex Schistosus Politorius,, Polierschiefer, from
Bilhn, in Bohemia - 380

Scientific News - - - - 381

(Z&uu

Mchcht'li- /fnks.JounuilJoim. lll/U.

( 'r//,j />/v/Av/,/.

Fio.2.
Cafswpeia/.

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minor

Big. I.

* *

Fc/-j.

{fad

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W! Davis's Machine for Glaziers:
Fig.4-

b 'i

A

JOURNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS

JANUARY, 1808.

ARTICLE I.

An Account of the relative Situations of the different Stars,
by ichich the principal Constellations may be distinguisJied.
From la Lande's Astronomy, third Edition, Art. 743,
$c*. k

JL HE great Bear is a constellation, which is always visi-
ble, it is easily known from the seven stars of which it con- J constella?
J ti >ns visible at

aists (see PI. I, Fig. 1). Four of them are in the body and all times.

three in the tail ; and the two farthest from the tail a and £ Ursa Major.
are called the pointers, because a line drawn from 6 to a, if
produced, witl pass on to the pole star, which is about as
far from a as a is from ??. The convex side of the tail is
turned toward the pole.

Cassiopeia is opposite to the great Bear, the polar star Cassiopeia,
lying between them, so that if a line be drawn from s Ursa*

* The following paper is a free translation of all that part of Mr. la
Landed work, -which can be of most service to those, who have not the
advantage of any astronomical instruments, by which they may measure
angles, or take observations on the meridian. At the same time, how-
ever, that I endeavoured to render the meaning as precisely as I could, I
tbought myself at liberty to make any small alteration, which would
rftore clearly point out the sense of the passage, or adapt it to the use of
the English reader.

N. R.D.

Vol. XIX— Jan* 1808. B Majoris

2 GUIDE TO THE CONSTELLATIONS.

Majoris through the pole star, it will pass through the mid-
dle of Cassiopeia. This constellation consists of six or
seven stars, which form a Y, or, as some describe it, a
chair turned on its back. This description is by no means
distinct, but there is little danger of any mistake; because
several of these stars are of the second magnitude (Fig. 2).

Ursa Minor. The little Bear is nearly of the same form as the great

Bear, but the figures though parallel are reversed with re-
■pect to one another. The pole star is of the 3d magnitude
at the extremity of the tail, the four next stars to it are
only of the 4th magnitude ; but the two last, which make
up the square, are of the 3d, and are called the Guards.
'These last are in a line drawn through the centre of the great
Bear, perpendicular to its longest side.

Arcturus. Arcturus, a star of the first magnitude in Bootes, is dis-

tant 31° from the tail of the great Bear; and if a line be
drawn through £ and r, the two stars at the extremity of the
tail, it will point to Arcturus.

Lyra and Ca- When the great Bear is on the meridian, Lyra- and Ca-
pella, two stars of the first magnitude, are seen, one in the
east, the other in the west, in a line drawn through the pole
star, perpendicularly to that which joins the great Bear and
Cassiopeia. Capella is to the east when the great Bear is:
under the pole ; and then, if their altitude is the same, it is-
almost equal to that of the pole star.

Draco. Draco is on the line drawn from a Ursee Majoris through

the Guards of the little Bear, between which and Lyra
may be observed the four stars in the shape of a lozenge,
which form the head; the tail lies between the pole star and
the body of the great Bear. The Hue through the Guards
points to v) Draconis, which is north of 0 and south of £
in the line, which is directed towards the pole of the eclip--
tic.

Cepheus. This line produced a little farther towards cT and g Dra-

conis will pass between 0 and «. Cephei.

Cygnus. The line drawn from the pole star to these two last men-

tioned stars in Cepheus will pass near to the tail of the
Swan, which is a beautiful object, and never sinks below the
horizon of London.

The constella- Having now gone through those constellations, which are

always

GUIDE TO THE CONSTELLATIONS. 3

always above our horizon, we will next proceed to those, tions visible in

3. winter's
which are visible in a winter's evening. evening.

About 7 or 8 o'clock P. M. in the months of January Orion,
and February, Orion is visible in the south. It consists of
seven stars, four of which are at considerable distances from
each other, and in the ceptre of them are three others of
the 2d magnitude, which are much closer and in a straight
line. This is a very remarkable constellation and may be
easily recognised if compared with Fig. 3.

The three bright stars in the belt of Orion point on one Pleiades and
side to the Pleiades and on the other to Sirius. Sirius is the Sirius«
brightest of all the fixed stars, and is remarkable for its ra-
diancy and brilliance: it lies on the south-east of Orion.
The Pleiades are on the north-west of Orion, and form a
group of small stars, which may be easily distinguished, as
they lie a little above the line drawn through the three stars
of the belt of Orion.

Aldebaran, or the Bull's eye, is a star of the first magni- Aldc&aran.
tude very near the Pleiades, and situated between them and
y the star in the western shoulder of Orion.

Procyon or Canis Minor is a star of the first magnitude, Procyon.
situated to the north of Sirius and the east of Orion : it
makes nearly an equilateral triangle with Sirius and the belt
of Orion.

The Twins are two stars of the second magnitude, situ- Gemini,
ated about midway between Orion and the great Bear.
They may also be distinguished by drawing a line from Ri- Rigel.
gel (which is 3 or that of the four outermost stars in Orion,
which lies in the south-west) through £ the eastern star in
the belt; since this will direct us to the heads of the Twins:
and again if we draw a line from f or s of Orion to eP and
£ of the great Bear, it will pass over one of the paws of the
Bear, and also by the heads of the Twins. This same line
will cross the feet of the Twins, and will pass very near a,
the star in the eastern shoulder of Orion. The feet of the
Twins are marked by four stars in a straight line perpendi-
cular to the direction here given.

The line drawn from Rigel through y in the western Taurus.
shoulder of Orion, will pass on the north through f a star
C£f the third magnitude, on the southern horn of Taurus : it

B 2 is

GUIDE TO THE CONSTELLATIONS.

Regulu*, or
Cor Leouis.

Cancer.

if about 14° from y Ononis, or the same distance at which
y Ononis is from Rigel. |3, the northern horn of the Bull,
is also called the foot of Auriga, it is of the second magnU
hide, and in the line drawn from a in the eastern shoulder
of Orion through f Tauri.'the southern horn. The ecliptic
passes between the two horns.

Leo. The Lion may be recognised by the same stars a and )3

in the great Bear, which serve to point out the polar star.
They arc distant about 45° north of the Lion, which forms
a large trapezium, in which there is a star of the first mag-
nitude called Regulus, or Cor Leouis ; it is in a line with
Rigid and Procyon, but at the distance of 37° from the lat-*
ter. $ also, a star of the second magnitude in the Lion's
tail, i6 a little on the south of a line drawn from Arcturus
to Regulus : it is 24* to the east of Regulus, and makes an
equilateral triangle with Spica Virginia and Arcturus.

Cancer is a constellation of small stars, which are distin-

Thc Nebulous guished with difficulty. The nebulous star in Cancer is less

*ursrJ\Cancer perceptible than the Pleiades, and we meet it nearly half
and Orion. r , „ ~ . . . , ^ T .

way between the centre of Gemini and the Cor Leonis, or

iu the line which joins Procyon and the tail of the great"

Bear. From u the middle star of the belt of Orion, there

proceeds a train, which is called the Sword ; it contains the

Nebula. Aline drawn through the Sword and the star «

points towards {, the southern horn of the Bull, and beyond

it to the middle of Auriga.

Auriga forms an irregular pentagon, the most northern
star of which is Capella : it is of the first magnitude, and
may be found by drawing a line through £ and a, the two
most northern stars in the body of the great Bear.

Aries, the first of the twelve constellations in the Zodiac,
consists principally of two stars of the first magnitude, si-
tuated near one another: & the more western of the two,
is accompanied by y, of the 4th magnitude, which has been
called the first star in Aries, because it was once the nearest
star to the equinoctial point. This constellation is in the
same line with Aldebaran and Procyon, from the former of
which it is distant about 35°.
*er*eu«. The belt of Perseus consists of three stars, one of which

is of the second magnitude. They form a curve with its

convex

Auriga.
Capella.

Aries,

GUIDE TO THE CONSTELLATIONS, §

eonvex side turned towards the great Bear. It might be
sufficient to mention, that they lie in the line drawn from
the pole star to the Pleiades ; but they may also be found
by producing a line through Gemini and Capella. The
line drawn from the belt of Orion through Aldebaran passes
through /?, the head of Medusa, which Perseus holds in
his hand : this star, which is also called Algol, is change-
able.

The Swan is a very remarkable constellation : it forms a Cygnus.
large cross, and contains a star of the second magnitude. A
line drawn from Gemini through the polar star will meet
the Swan at about an equal distance on the opposite side:
at some seasons of the year they are both at the same time
above the horizon. But we shall have another means of
distinguishing this constellation, when we are acquainted
with that of Pegasus.

The square of Pegasus is formed by four stars -of the se- Pegasus.
cond magnitude: the most northern is the head of Andro-
meda. The line drawn from « and 0 of the great Bear
through the pole star will pass across the middle of these
four stars. A line drawn from the belt of Orion through
Aries will lead to the head of Andromeda : one drawn from
the Pleiades through Aries will lead to y iu the wing of Pe-
gasus : the other two stars are to the west ; the northern is
/3 and the southern a.

The diagonal drawn through y and 0 passes on north-
west towards a. in the tail of the Swan : the other diagonal,
drawn through « and the head of Andromeda, points uo.th-
east to the belt of Perseus, having tirst parsed (3 iu the gir-
dle, and y near the foot of Andromeda: these two stats (/2
and y) are of the second magnitude, and divide the space
between the head of Andromeda and the beit ot Perseus
into three equal parts. The line which connects them is
at right angles to that which would join Aries aud Cassio-
peia.

The constellations visible in a summer's evening do not The constella-
possess such strongly distinguishing characters as those, tio&s visible in
which we have just been describing : but a person who has tveni„E,
made himself acquainted with those, which may be seen in

winter,

6

GUIDE TO THE CONSTELLATIONS.

winter, will find that the knowledge of them will assist him
very much in ascertaining the rest.

Spica Virginia. The m\^\e star (f) m tne tail of the great Bear is on
the meridian over the pole star, about 9 o'clock in the latter
end of May. Spica Virginis, a star of the first magnitude,
will then appear on the meridian in the south at the alti-
tude of about 28° 30'. The diagonal drawn through a and
y in the great Bear will nearly pass through this star, al-
though at the distance of 68°. Moreover Spica Virginia
makes nearly an equilateral triangle with Arcturus and the
Lion's tail, from which it is distant about 35°.

Comi>. At this time also the four principal stars in the Crow are

a little to the right, below Spica Virginis. They form a
trapezium, and are situated in the same line with Lyra
and Spica Virginis.

Hydra. If from £ and y, the last stars in the square of the great

Bear, a line be drawn through Regulus, it will meet, at the
distance of 22° to the south, the star called Cor Hydra?.
The head of the Hydra is to the south of Cancer, between
Procyon and Regulus ; but it is a little south of the line
which joins them. This constellation extends from Canis
Minor to the part of the heavens, which is situated below
Spica Virginis and part of Libra. Between it and the Crow
is the Cup.

Lyra, a star of the first magnitude, is one of the most
brilliant in the whole heavens. The situation with respect
to Arcturus and the pole star is such, as to make nearly a
right angle to the east in Lyra.

The Northern Crown is a small constellation, situated
between Arcturus and Lyra: it is near Arcturus, and may
be easily distinguished by the seven stars, of which it is
composed; they are arranged in a semicircular form, and
one of them (a) is of the second magnitude, f and *?, t)ie
two last stars in the tail of the great Bear, are in a line with
the Crown.
Aquila. The Eagle contains a very bright star of the second mag-

nitude, which is in the south of the Lyre and the Swan. It
is easily distinguished, because it is situated between # and
y, two stars of the third magnitude, which are very close
and form a straight line with it.

The

Crater.
Lyra.

Corona Bo-
red is.

GUIDE TO THE CONSTELLATIONS. 7

The great circle, which passes through Regulu9 and Spica Scorpio.
Virginia, is nearly the same with the ecliptic, and if it be
produced to the eastward, it meets the Scorpion, a remark-
able constellation on account of the four stars in its head,
which form a large arch fVora N. to S. round Antares, or the Antares.
Cor Scorpionis, which is placed as a centre to them. One
of the four stars is of the 2d magnitude, and Antares is a
bright star of the first magnitude.

The Balance contains two stars of the second magnitude, Libra,
which form the two scales : the line which connects them is
nearly perpendicular to that which may be drawn from Arc-
turus to Antares, and they lie a little to the south of the
middle of this line of direction. The southern scale is si-
tuated between Spica Virginia and Antares, and these three
stars a;e all very nearly in the ecliptic. Spica Virginis is at
the distance of 21°, and Antares at the distance of 25°,
from the southern scale.

Sagittarius is a constellation, which follows the Scorpion, Sagittarius.
being a little to the east of it. It is in the line, which,
passing through Spica Virginis and Antares, follows nearly
the direction of the ecliptic : it contains several stars of the
third magnitude, which form a large trapezium, two stars of
which, together with two others, form a second trapezium,
perpendicular as it were to the first. Sagittarius may be
known by a line drawn through the middle of the Swan and
EagJe : for it is 3.5° south of the Eagle, or nearly the same
distance fr<fm it as the Eagle is from the Swan. Sagittarius
may also be known by the diagonal drawn from the head
of Andromeda to « Pegasi, the same line, which produced
towards the north points out the belt of Perseus.

The line drawn from Antares to the pole star passes through Ophiucus and
Ophiucus, or Serpentarius, and then through Hercules. It Hercules,
is rather difficult to know these constellations, and therefore
they must be described more particularly. The line drawn
from Antares to the Lyre passes near the head of Ophiucus,
which is not far from that of Hercules, and lies to the south-
east of it. They are marked by two stars of the second
magnitude, and the line which connects the^i points to the
Crown; it also passes through y Hercuii? at the distance of
13° from the head of Hercules. jS Her<:ulis is at the distance

of

8 Cl'IDE TO THE CONSTELLATIONS.

Ophiucus and 0f 30 t0 the north-east of y, the line drawn from it \o y
points on the north to g Herculis, and on the south, or ra-
ther south-west, to a Serpentis, which forms nearly an equi-
lateral triangle with the head of Hercules and the Crown.
The line drawn from the head of Ophiucus to the southern
scale of the Balance passes through £ and g Ophiuci, two
stars of the third and fourth magnitudes, which are at the
distance of only 1° 20' from one another, and in the line
drawn perpendicular to that which was last described, o
lies to the north-west of g, and these two stars point on the
south-east towards f in the western knee of Ophiucus, which
is 7|° from g. This same direction will lead near to ^, the
star in the other knee of Ophiucus, which is about 9|° to
the south east of f. These same stars £ and g point a little
below cc Serpeutis, and, if considered as one group, they
would make nearly an equilateral triangle with a, Serpentis
and 0 in the northern scale, 4§° north-west of <* Serpentis
is £, and 3° south-east is g of the same constellation. The
direction of these three stars is also towards I and g Ophi-
uci, which are 11° from g Serpentis. /3 and y, the two stars
in the eastern shoulder of Ophiucus, are in the line drawn
from the head of Hercules to the head of Sagittarius : this
line passes a little to the south-east of the head of Ophi-
ucus. # is 8° and y 11° from the head of Ophiucus. A
line drawn through them would pass between the two head*
of Hercules and Ophiucus: the line connecting these two
heads points to 0 at the extremity of the tail of the Ser-
pent, which is 22° east of the head of Ophiucus. The
line drawn from the most eastern stars in the Crown (which
are on the side turned towards the Lyre) to a Serpentis
passes by the head of the Serpent, between y and 0, two
stars of the third magnitude : $ is the more western of
the two. The western foot of Ophiucus lies between An-
tares and /3, the northern star in the head of the Scorpion :
the eastern leg is between Antares and y, Sagittarii, which
is the highest and most western star in the how.
Capricorn. Capricorn may be found by producing the line drawn

from the Lyve to the 'Eagle: this line will pass through a.
and £ two stars of the third magnitude in the head of Capri-
corn. These star* are only 2° from one another. Farther

to

GIHDE TO THE CONSTELLATIONS. Q

to the east by 20° are two other stars, y and £, situated east
and west about 2° asunder: they are in the tail of Capricorn.

Fomalhaut, or the mouth of the southern Fish, is a star of Fomalhaut.
the first magnitude, and is pointed out by a line drawn from
Aquila to the tail of Capricorn. Fomalhaut lies about 20°
to the south east of £ Capricorni.

The Dolphin is a small constellation situated about 15° Delphlm*
east of the Eagle. It consists of a lozenge of four stars of
the 3d magnitude. A line drawn from the Dolphin perpen-
dicularly through the middle of y, «, and /?, the three stars
in the Eagle, will pass through 0 in the extremity of the tail
of the Serpent.

Aquarius is found by a line drawn from the Lyre through Aquarius
the Dolphin, and carried on about 30°, which is as far be-
yond the Dolphin as the Dolphin is distant from the Lyre:
Aquarius lies a little to the east of this line. A line drawn
from the Dolphin to Fomalhaut will pass entirely across the
constellation of Aquarius, and it will pass about midway
between a and (2, two stars of the 3d magnitude, in the
shoulders of Aquarius. They are the most remarkable stars
in the whole constellation, and are about 10° distant from
one another.

The Whale is a large constellation, situated on the south Ce'.us.
of Aries, and extending through a space, which is equal in
length to the distance of the Pleiades from the four stars in
Pegasus. A linedravvn from the girdle of Andromeda, and pas-
sing between the two stars in Aries, will meet «, a star in the
mouth of the Whale, which is of the 3d magnitude, and 25°
from the horns of Aries. A line drawn from Capella through
the Pleiades will also pass south of a. Ceti. A line drawn
from Aldebaran through the mouth of the Whale will pass
through & a star of the 2d magnitude in the tail: £ \H
42° l.v st of «, and very near the constellation of Aquarius.
The square in Pegasus is alone sufficient to point out the
Whale; for the line drawn through the two most southern
of these stars passes between Aries and the knot of the
Fishes, and will meet the head of the Whale: and the line
drawn through the most eastern stars in the same square
points to the tail. Between the head and the tail are situ-
ated y and £, and between £ and the tail is 0, a changeable

star,

10 GUIDE TO THE CONSTELLATIONS.

6tar, which is sometimes of the 2d magnitude, and sometimes
quite invisible. £ lies about half way between a and o.

Pisces. The Fishes, which form the twelfth sign of the Zodiac,

are not a very remarkable constellation. One of them lies
on the south side of the square in Pegasus, under a and y ;
the other is on the east of the square, and between the heads
of Andromeda and of the Whale. The star a in the
knot of the string which joins the Fishes is of the 3d
magnitude, and is the most remarkable star in the whole
constellation : it is situated in the line which joins the head
of Andromeda and o the changeable star in the Whale ; it is
also in the line drawn from the feet of the Twins through
Aldebaran and produced towards the west. This star- (*
Piscium) is 40° west of Aldebaran, and makes a triangle
with x Ceti and (3 or y Arietis, which is right angled at the
star in the Fishes.

We have now given an account of the principal constel-
lations, from which the rest may easily be known with the

Pole of the assistance of a globe. But it may be necessary to add some
directions for finding the pole of the Ecliptic, which is one
of the most remarkable points in the heavens ; and one, with
which a person should be particularly acquainted, who
wishes to become familiar with the heavenly bodies. It is
situated in the constellation of Draco, in the same line with
y and ^, the two stars in the great Bear, which are nearest to
the tail ; it makes almost an equilateral triangle with Lyra
and a Cygni ; it is also in the line drawn from a point half
way between the two eastern stars in the square of the great
Bear, and produced through the middle of the guards of the
little Bear 3° beyond u Draconis. u may be easily known,
since it is nearly in the same line with the three stars of the
same constellation, marked 0, '/? and £, whith are situated in
the line drawn from Arcturus to Cepheus and Cassiopeia,
that , passt s between £ and g Draconis on the opposite
side of the pole of the Ecliptic. £ and i are near to one
another, and in a direction parallel to the tail of the little
Bear, so as to point to the head of the Dragon. The mid-
dle star » is thai, towards which the guards of the little Bear
point. Lastly, the pole of the Ecliptic makes a right angled
and isosceles triangle with the pole star and /5 Ursa? Minoris,

which

USES OF MALLEABLE ZINC. \\

which is the more northern of the guards; the right angle is

at (3.

The distances of some of the most remarkable fixed stars Distances of

will y,ive the reader a better idea of the magnitude of degrees, |°ed stats *°

and are, therefore, added.

o f ft

Arcturus to * Ursa? Majoris 30 29 0

The two outermost stars in the belt of

Orion 2 44 O

The two stars in the shoulders of Orion 7 32 30

Capella to Castor (a Geminorum) • • 30 0 0

Aldebaran to Sirius • ••• 45 53 20

to Capella ...30 43 30

to the western shoulder of

Orion 15 47 36

Sirius to Rigel (£ Orionis) 23 40 0

Procyon to Regulus (a Leonis) .... 37 20 0

to Rigel 38 27 30

Regulus to Spica Virginis 54 2 0

Arcturus to Spica Virginis 32 2 0

to Regulus^ 59 49 0

Spica Virginis to Antares 45 52 0

Antares to Arcturus 56 4 10

to Aquila 60 9 30

Lyra- to Spica Virginis 87 46 0

to Aquila 34 9 0

to the tail of the Swan 23 52 0

The tail of the Lion (0) to Spica Vir-
ginis 35 2 10

N. R. D.

II.

On the Advantages of Malleable Zinc, and the Purposes to
which it may be applied. By Mr. Charles Sylvester.

To Mr. NICHOLSON.

Sir,

,/a.T the time I had some conversation with you on the sub- Of the uses of
jcct of malleable zinc, 1 was not aware of all the advantages zmc*

possessed

12 USES OP MALLEABLE ZINC.

possessed by that metal, though I could fully speak to the
facility with which it eoulcl be worked into vessels, and of its
application to other purposes. I was still, for want of longer
experience, not decided as to its changeability when exposed
to the action of water and air.
Zinc might be From the great affinity which zinc possesses for oxigen, it ,
supposed ea- might be expected to oxidate with great avidity, and on that
account be rendered useless in the situations above alluded
Put it is not, to; but, to the astonishment of most theorists, the contrary
proves to be the case. Many specimens of zinc, both in
the state of sheets and wire, have been exposed in the open
air, as well as in damp rooms, without undergoing any other
change than that of colour. Indeed it appears, that a piece
of polished zinc will lose its lustre, and assume a blue gray-
colour, when exposed in a damp room for the space of a few
except super-. *ce*8. An oxide is formed upon the surface, which, though
fccially. of an imperceptible thickness, is so exceedingly hard, and at

the same time so insoluble, that it resists ail the future at-
Less affected tacks both of the air and of water. From numerous expe-

tUan copper by riments I have ascertained, that copper is much more liable
seawater. .

to waste than zinc in sea water, and even in strong solutions of

muriate of soda. There cannot be therefore a doubt of its

ready application to the sheathing of ships.

Its superiority For the purposes of roofing houses, forming cisterns,
over lead or Q . i » .

copper for ra- PumPs> pipes, &c, it possesses many advantages over lead

rio us purposes. and copper. In the first place it is equally durable with those
metals, without possessing any of their deleterious effects. It is
also capable of being lapped and soldered with the same faci-
lity as sheets of copper, lead, or tinned iron plates ; and may be
worked to advantage equally by the brazier, the plumber, and
the tinman. Its little specific gravity, which is to that of lead
as 7 to 11, compared with its greater strength, which is 15
times that of lead, gives it a decided advantage over that
metal in point of price. Allowing the sheets of zinc to be
only |th the thickness of lead, the zinc will come in at one
third the price of that metal. Its advantage in a similar
point of view over copper will not admit of a question.
fTeneral size of The sheets arc generally made 2 feet by 4, and can be
the sheets. xo\\^{\ as thin as G ounces to the square foot.

Sheets

MACHINE FOR PAINTERS AND GLAZIERS. 1$

Sheets or wire of zinc may be purchased of Mr. Philip
George of Bristol, or of Messrs. Harvy and Golden, 98,
Iloundsditch, London: Of whom may also be had, vessels
and utensils of any form. They likewise undertake the roof-
ing of houses, or sheathing vessels, with zinc.

By giving the above a place in your much esteemed Journal,
vou will much oblige

Your obedient servant,

CHARLES SYLVESTER.

P. S. I observed some time ago in your Journal, experi-
ments by Mr. Davy on the subject of the production of the
muriatic acid and fixed alkali by galvanism, in which some of
my former experiments were alluded to. I do not think Mr.
Davy is decisive on the subject, and have not a doubt of very-
soon confirming all that I have previously asserted.

Sh<> fuld, Nov. 20, 1807.

III.

Description of Mr. Davis's improved Machine for Faint ers
and Glaziers'*,

T

HE frequent accidents which happen to painters and Machine for

glaziers, from the unsteadiness of their machines, and the preventing ac-
to . ,._.,. .11 cidents to pam-

cunsequent misery brought upon their families, stimulated ters and gl*-

Mr. Joseph Davis, of the Crescent, Kingsland Road, to en- ziers»

deavour at their improvement. The result was the machine

delineated in plate I, which may be made perfectly firm and

secure, without occasioning any injury to the wainscoting or

paint. In those cases however, where the bottoms of the

windows are flush with the floor, as is usual in the best

apartments of modern houses, neither the common machine,

nor this with the improvement intended for general use, can

l>e applied : but Mr. Davis has contrived an additional piece

$o be used on such occasions, which renders it equally secure.

* From the Trans, of the Society of Arts for 1806, p. 138.

]4 0N TIIE ATTRACTION OF SURFACES,

Description of Fig. 4, plate I, Represents the machine: the part a is si -

and placer's* miliir to l,,at useJ % gHiziets, which is placed on the outsidt

machine. of the window. b, is an additional moving piece, which

presses against the inside of the window frame, and is brought

nearer to, or removed farther from it, by means of the male

screw c, and its handle d.

Fig. 5, Shows the lower part of a window, and the manner
in which the moving piece b, including a female screw, acts
against the inside of the window frame.

Fig. 6, Shows a cross bar introduced in place of the moving

piece last mentioned which bar extends from one window side

% to the other, ami explains how the machine may be used,

where any injury might arise from screwing the moving piece

in the centre of the recess of the window.

The general improvement consists In the use of a screw on
that end of the frame which is within the house, and which
keeps the machine steady and firm, instead of the two upright
irons, which are put through holes made in the top plank of
the machine, in the common mode, and which occasion the
machine to be very unsteady in use, and liable to accident.
There are two blocks marked rf, c/, in Fig. 4, which may be
occasionally put in, or taken out, according as the stone work
under the window may require.

IV.

Answer to some Observations of Mr. Dispan on the pretended
Attraction of Surface between Oil and Water: by J. Car-

RADORI DE PRATO, M. D*.

Oil spreads on JlvJL R. Dispan, a celebrated professor of chemistry, imagines
attempUopre- tnat tne phenomenon of the spreading of oil on the surface of
serve their le- water arises simply from an effort of libration between two
two fluids of bodies of very different specific gravities, as oil and water
different gravi- are. " A drop of oil," says he, " falling on still water, is a
sphere composed of extremely movable particles, disposed by
its difference of gravity to yield the level to the water, and

• Annales de Chimie, vol. LXII, p." 65, April, 1807.

consequently

ON THE ATTRACTION OF SURFACES. 15

consequent])' to apply itself to the whole surface in a very
thin stratum. At the instant of its fall the drop of oil dis-
places a volume of water equal to its momentum. But
presently, as the fluidity of the oil gives its particles the fa-
culty of gliding one upon another, the reaction of the water
having raised the drop, its particles, finding no obstacle, slide
down on all sides with rapidity, till the whole is reduced to a
very thin stratum. Thus in this fact there is nothing, that
justifies the pretended affinity of surface between oil and
water: on the contrary, instead of an application or reunion
of surface, there is rather a division and a separation; since
the drop of oil, which is spread upon the water, divides it-
self into an infinite number of others."

With all the respect due to the talents of the professor, it This opposed
appears to me, that his explanation is strongly contradicted y acts*
by the facts on which mine is founded. I have adduced se-
veral experiments, in two papers inserted in the Transactions x
of the Italian Society of Sciences, Vols. XI and XII, which
show, that there is a, physical force, by which the spreading of
oil on water, and on other fluids, is determined. With these
professor Dispan could not be acquainted, otherwise he
would have refrained from giving his explanation of this phe-
nomenon.

I would ask Mr. Dispan, how he accounts for the spread- It is not nee«*.
ing of oil on water, when the drop is not let fall upon it, but s,ar*r inatthf
- , i. , • , , • , , • . droP should

cautiously applied, without making the least impression upon fall, so as to

the water, so that no reaction is produced, that can over- cause r<?act-00'
come the affinity of aggregation of the oil. A drop so ap-
plied certainly spreads completely, and particularly if the
water expose an extensive surface. It will be still more dif- Juice of spurgs
ftcult for him to explain, how a drop of the milky juice of spreatswte
spurge, applied on water in the same manner, spreads over it
in the twinkling of an eye, and covers it with a very thin pel-
licle; or even why a small quantity of wheat flour, or any Farinaceous
other fecula, thrown on water, instead of falling to the bot- powders to th#
torn, spreads on its surface. There is no libration, no effort,
no reaction of the water here. It appears to me, that these
facts are much better explained by the principle I have esta-
blished

\6 ON THE ATTRACTION OF SURFACfS.

blished in the two papers abovementioned, than by the mecha-
nical operation imagined by Mr. Dwp&n.
The oil collect- J |inow wt\\f thHt ^ (jrop 0f vl[ breaks, after it has spread

vain into i i • n •

drops no aigu- upon the water, and that it collects into other very small

jueut. drops: but this dens not hinder the spreading of the oil

from being occasioned by a force, which has compelled it
to diffuse itself over the surface, and before acted for a
moment.

Thatasubse- But it is not true, that, if, after the spreading of the first

CT'et tlr°P' a stJCon(* ancl a tnirci l)e appl',e(l to the surface of the

•piead, not ow- water, they do not spread like the first, because they find an
Stance tfthe oi)StacIe t() their movement, and to their gliding on the water,
former, since it in the fragments of the drop of oil, which was before spread,
pm freeft-oin am' occl,P'ec' Ml surface: for the phenomenon does not take
•il. place, though the drops be applied far from the space occu-

pied by the diffusion of the first drop; and though the eye,
assisted by a lens, have previously ascertained, that the sur-
face of the water is free from every obstacle in the place
to which the drop of oil is afterward applied.
Oil no obstacle I could prove to him likewise, that these obstacles are not

to the spread sufficient to prevent the diffusion of fluids and other substan-

of the juice of r , .. /

spurge, which ces» that spread on water. Let a drop or oil spread over the

impels it in a surface 0f some water in a goblet, and when it has completely
globule lo one & . . ,f.

*ide$ covered it, apply a drop of the juice of spurge; this fluid will

diffuse itself over the surface with astonishing rapidity, though

' the surface is already occupied by the oil spread on it before,

and, displacing the oil, will force it to accumulate in-one or

two drops against the side of the glass. It will be just the'

•rof flour, same, if, instead of the juice of spurge, a little flour be ap-

which collects pjj^j to the water; for this will equally spread over the sur-

tbe 01! in a glo- l , , , .,-?,,,,. •

bule under it. wee ot the water, and the oil will be obliged to unite into a

single drop or globule, which will sink under the flour, that
occupies the surface. What other reason for these pheno-
mena can there be, than the force of adhesion between the
surface of the water 'and these substances?
Adhesion has Lastly I have to observe, that I never asserted there was
some proper- any thing of chemical action in this phenomenon. I only
mon withche- saiu" m m> ^rst Paper on the attraction of surfaces, Vol. XI of
aiical affimity. t|ie Italian Transactions, that the force which natural philo-
sophers

MEDICINAL PROPERTIES OF PLANTS. J7

sophers have distinguished by the name of adhesion has some
properties in common with chemical attraction, such as the
point of saturation, and elective affinity, and that hence it
Appeared to me, to be very properly termed attraction of
surfaces.

I shall not hesitate however, to renounce the principle I
have adopted, that of an attraction of surfaces, and retract
the explanations of some interesting phenomena, which I have
deduced from this principle, and given in the papers already
mentioned, if convincing facts and just reasonings show me
their incompetency.

Abstract of an Essay on the Medicinal Properties of Plants
compared with their external Form and natural Classifica-
tions: by Mr, Decandolle*.

O branch of study deserves the name of science, till it Indication of
is sufficiently advanced, to be able to determine facts a priori. *he virtues o{
The materia medica, which rests entirely on the basis of ex-
perience, has but three means of forming a judgment of the
properties of substances; which are, their sensible qualities,
their chemical composition, and their natural analogy. The
object of Mr. Decandolle's work, which forms a quarto vo-
lume, is to ascertain how far the analogy of the forms of
vegetables affords indications of their properties.

Camerarius first decidedly took up the affirmative side of Have plantssi-
this question in \699- He was followed by Isenflamm, ^nce'simii
Wilka, Gmelin, and more especially by Linneus and de Jus- lar virtues-?
sieu. On the other hand Vogel, Plaz, and Gleditsch wrote
against it. Notwithstanding what has been written by these
learned men, Mr. Decandolle has contrived to treat the ques-
tion with some novelty, not only in consequence of the pro-
gress, that the study of natural affinities has made within these
twenty or thirty years; but because, confining himself ex-
clusively to no system, he has formed his deductions not from

* Annates de Chimie, Vol. LXI, p. *U, January, 1807.
Vol. XIX.— Jan. 1808. C a fe\r

18 MEDICINAL PROPERTIES OP PLAXTS.

a few solitary families, but from all that compose the veget-
able kingdom.

Arguments for He commences with establishing the general proofs, that the
medicinal properties of plants are analogous to their external
forms. In fact no one will question, that the properties of
medicines depend on their physical constitution or chemical
composition: but in organized bodies the nature of a produc-
tion is determined by the form of the organs, since the same
aliments, digested by different beings, afford different results;
consequently the productions bear some relation to the forms.
This reasoning is applicable to the vegetable kingdom, though
its classification is not derived from the organs of nutrition,
but from those of reproduction; for the natural classes deduced
from one function necessarily agree with those deduced from
another function.

Observations These general inferences are confirmed by the observation,

pending to con- tj^ herbivorous animals frequently avoid or seek all the

Arm it. • n J

plants of the same family: that those, which seem deter-
mined to feed only on a single plant, frequently submit to eat
plants of the same genus, or of the same family : and that para-
sitic plants, particularly funguses, display the same preference
for certain genera, or certain families. To this may be ad-
ded, that several foreign drugs, which were formerly supposed
to be the production of a single plant, have been found oa
inquiry to be furnished by several species of the same genus;
and that with respect to indigenous simples it is no new thing,
for species of the same genus to be substituted for each other.
And we may observe, the narratives of travellers inform us,
that plants of the same family are often employed for similar
purposes in countries remote from each other.

Y«t many ex- Notwithstanding these assertions however, which the au-

ceptions. thor supports by several examples, it cannot be denied, thai

vegetables very closely allied present very striking anomalies.
In order to estimate the real weight of these, the author takes
a review of the rules of comparison between forms and pro-
perties, and this is the part of his work that displays most
novelty.

Resembtance &• ^n tne ^rst P^ace "e observes, that, though M«e arrange

in some fami- Species under genera, genera under families, and families u li-
lies ©f plants 7- ,

MEDICINAL PROPERTIES OF PLANTS. 19

der classes, in a uniform manner, the groups are far from be- closrr than

» i „,, . others,

ing separated from each other in an equal degree 1 hus in

certain families plants differ from each other by slight modifi-
cations only, while in others they are distinguished by more
important characteristics. The analogy between their proper-
tics may be presumed to be proportional to the analogy of
their structure.

2. Secondly, it is contrary to the spirit of the method, to Similar organs

„. c ... only and simi-

compare the properties ot a given organ, or a given juice, jar :ujceg

with those of another organ, or another juice. This however should becom-

is one of the most frequent causes, that have led to mistakes Pare "

on the question. In this discussion the author introduces by

the way some new views respecting the structure of bulbs,

the body of which he proves to be in reality an abortive

stalk, and not a root.

3. The circumstances of the age of a plant, the season in Adventitious

which it is gathered, the soil in which it has grown, and the circ,,"lstances.
Y o * should be simi-

d eg ree -of light to which it has been exposed, are so many lar.

causes of crrour, that are to be avoided in the comparison.

4. Unequal mixtures or unequal combinations of different Principles
principles are found in the organs or juices of certain fami- equulv"63'""^
lie.s; and in these families several of the most apparent ano-' or combined.
malics occur.

5. In the comparison of properties, we should pay at ten- Modes of pre-

tion to the difference that may exist in the mode of extracting ParaUJn ;il!er

J . & properties.

and preparing a drug; for these circumstances frequently

have as much influence on their properties as their intrinsic

nature.

6. 'We should -exclude from the comparion the mechanical Accidental

... . . . - . . , qualities must

or accidental properties, that arise From circumstances inde- be excluded.

pendent of the true nature of substances.

7- Above all we should most scrupuously attend not to the Not the paiti-
,„ c iL ;• .. • '. c , . , ,. cular result but

result ot the application ot a. medicine, but to its mode ot act- general mode

ing; for medicines similar in reality act differently according OI* action to be

i i-i i- i i • . • • • regarded.

to the oigan to which they are applied, or tne casein which

they are administered, and the contrary.

After laying down those principles th-e author takes a view

of all the families, that compose the vegetable- kingdom ; and

details live properties of all ihe plants that belong to them.

C 2 including

CO

ANALYSIS OF LAZULITE.

Mr D'swork
a complete
view of the
properties of
Tegeubles.

Of 76 families
analogy little
violated in 46,
and not at all
in 23.

including not only those that are admitted into our European
Pharmacopoeias, but those that arc employed medicinally by
the inhabitants of any part of the globe. In this respect Mr.
Dccandolle's work gives a complete and methodical display
of the properties of vegetables: and the result of this exhibi-
tion is, that, of seventy-six families, the properties of which
are known, there are thirty-seven where the law of analogy is
violated, twenty-three where it is completely preserved, and
forty-six in which it is observable with a small number of
exceptions.

VI,

Analysis of the Siderite, or Lazulite i by Messrs. Tromms-
dorff and Bernhardi*.

Lazulite of
Stiria.

T:

Analysed by
Klaproth,

and by Heim

Little analo-
gous to feldt-
spar.

Its usual form.

HE lazulite was found at first near Waldbach, in
Stiria, and afterward in the environs of Wienerisch-
Neustadt. It is sufficiently known from the works of vari-
ous mineralogists. Some time after a mineral was discovered
in the country of Salzburg, which was called mollite; but
baron Moll has given it the name of siderite, on account of
its acknowledged identity with this fossil according to the
researches of Mr. Mohs.

Though Klaproth found in the lazulite of Vorau silex,
alumine, and iron, he could not ascertain their proportions,
from the smallness of the quantity he had to examine. An
analysis of the siderite by Heim gave 0*6'5 alumine, and
0*30 iron.

It is strange, that Messrs. Klaproth, Estner, and Mohs,
should fancy there was a great analogy between the lazulite
and feldtspar, as analysis shows this analogy to be very
slight; and that between their crystallizations and contexture
is equally so.

The most usual form of tbe lazulite is a regular octaedron
with truncated edges, passing to the regular rbomboidal

* Annales de Chimie, Vol. LX1I, p. 43, April, 1807. Abridged from
Gehlen's Journal by Mr. Vogel.

dodecaedron

ANALYSIS OF LAftTJLITE. 21

dodecaedron. The faces of the octaedron make an angle of
109a 28' lfi": those of the dodecaedron an angle of 120°:
and the former cot these at an angle of 144° 44' 8". Be-
side these severtl smaller faces were observed, which were
not easy to determine, because the specimens were not
very distinct.

It is not uncommon to meet with flattened quadrilateral Varieties of
prisms, the faces of which form angles of 101° 32' and form* %
78° 28'; angles that occur in several minerals, particularly
in the calcareous spar. At the extremities of these prisms
were faces in greater or less number, which we could not
ascertain.

As to its contexture, we could not find it split decisively Not fissile.
10 any direction.

With respect to its crystallization it can be compared only Resembles th«
with the spinelle, with which Mr. Haiiy classes the ceylanite Spme
or pleonast. As analysis informs us too, that it resembles
it in its constituent parts, we must consider them as similar.

The following is a comparative analysis of them.

Of the ~ei.
Of the ceyla- °J£?
Of the spinelle by spinelle nite by . .
V.u,u.lta. by Kla- Coll*. ^^
proth. Desco- , ff
tils.

Alumine 860 82*47 745 68 66 Comparative

Magnesia 8'5 S'7S 8.25 12 18 analys,s-

Silex 15*5 2 10

Lime ' 0*75 2

Oxide of iron • • 1'5 l() 2'5

Oxide of chrome 5 25 6*18

We find that alumine united with magnesia must be con-
sidered as the essential part of the mineral.

As Mr. Bernhardi took upon himself to describe the cha-
racters of the lazulite, Mr. Trommsdorff attended more
particularly to the analysis. He proceeded as follows. its analysis.

A. A hundred grains of siderite strongly calcined in a calcined
covered crucible lost 5 grains of their weight. The fine
blue colour had disappeared, and was changed to a yellowish
white.

B. The

22 ANALYSIS OF LAZVLITE.

Treated with B. The calcined mineral was easily ground, and did not
soda. 7

scratch the agate mortar. One hundred grams were urged

to a red heat with 400 of canstic soda: and after a pasty fu-
sion there remained a mass, which, diffused in water, afforded.
a turbid solution void of colour. This was supersaturated
with muriatic acid; evaporated and redissolved in boiling

Silex precipi- water; when silex was precipitated from it, which weighed
ut. " 10 grains after calcination.

C. The boiling liquor was precipitated by carbonate of soda.
tfo ulutineor F). The precipitate, containing neither glucine nor yttria,

ytiria. vvas boiled in a lixivium of canstic soda, which effected a

partial solution. The spongy, insoluble, brownish red resi-
duum was set apart.
Lixivium satu- ^. The soda lixivium (D) was supersaturated with muri-
■ imted with nm- atic acid, and the boiling liquor precipitated by carbonate
ahlmine'seua-1 °^ s0^a' ^he white precipitate, after sufficient elutriation,
rated. and being strongly calcined, left C6 grains of pure alumine.

Lime. F. The reddish brown residuum (D) dissolved entirely in

muriatic acid. The solution was concentrated, and the ex-
cess of muriatic acid saturated with ammonia. A little con-,
centrated sulphuric acid was then poured in, which threw
down a white precipitate. This was washed several times in
cold water, and calcined, after which (5 grains of sulphate of
lime, being equivalent to 2 grains of lime, remained.
Oxide of iron. Qf Into tne liquor from which the lime had been precipi-
tated prussiate of potash was poured, and the precipitate
produced contained 2'5 grains of oxide of iron.
Magnesia. "• * ne U(luor decanted from the prussiate of potash was

mixed with carbonate of soda, and kept some time boiling,
A white substance fell down, which, after calcination, con-^
sisted of 18 grains of magnesia.
Its component ^ne hundred grains of the calcined fossil therefore con-
paru. tained

Silex 10 (B)

Alumine C6 (E)

Magnesia 18 (II)

Lime- 2 (F)

Oxide of Iron • • 2*5 (G.)

Loss 1-5

100 "

The

ON PREPARING PURE BARYTE8. £3

The blue colour of the fossil appears to be owing to the Blue colour

degree of oxidation of the iron ; and this is so much the more owing toa11

... ■»« ' ~,-r»." ' ', . *. _ oxide of iron,

probable, as Mw Hitter has announced the existence of a

blue oxide of iron.

Jt is true Mr. Guyton has discovered also a blue sulphuret Not asulphu-

of iron, to which he ascribes the colour of lapis lazuli: but re* as Guytoti

in this case perhaps the sulphur may serve to produce this su^gse *

minimum of oxidation. Besides, direct experiments on the

lazulite have convinced the author of this memoir, that

it does not contain the least trace of sulphur or sulphuric

acid.

VIT.

On the Preparation of pure Barylcs : by Mr. Robiquet*.

N a note inserted in No. 183 of the Annales de Chimie, Mr ^'Arcet*-
[see Journal No. 76, p. 66], on the decomposition of acetate process for ob-
of barytes by means of soda, Mr. d'Arcet points out as a ^"^ J^e
more economical and certain process for procuring pure ba- preferable to
rytes, to decompose any barytic salt, particularly the mu- e conaraon'
viate, by a caustic alkali. I conceive however, that the pre-
ference he gives to this process over that more generally
employed, namely the decomposition of the nitrate by means
of heat, is not well founded.

If we consider the subject in an economical view, we find Comparison of
in both cases a soluble barytic salt is first to be formed: that lhera*
in the first case we cannot employ liquors sufficiently con-
centrated, to prevent any barytes from remaining; in a state Losses in his

. way,

of solution: that whatever precaution we take in preparin°*

the caustic alkali by means of lime, a portion will always
become carbonated, were it only during the processes of fil-
tration ; consequently there will be so much to be deducted,
from the quantity of barytes that might have been obtained :
that besides, as the liquor must be shaken during the preci-
pitation, a certain portion will then become carbonated : that
a loss is occasioned by the washing likewise : and lastly, that

» Annales de Chimie, Vol. LXII, p. 61^ April, 1807.

a great

34 ON PREPARING PURE BARYTES.

a great deal more becomes carbonated by dissolving it afresh

in boiling water. It is obvious, that all these deductions

XT . ,. taken together will amount to a considerable sum, while in
None m trie °

other.] the decomposition of the nitrate we obtain the whole of the

quantity it contained, which amounts to nearly half the
weight of the dry salt; and that besides this process is neither
difficult nor expensive, to those who know how to conduct it
properly. The following are the precautions to be taken, to
ensure its success.

Process for de- Let a covered crucible be nearly two thirds filled with dry

composing the and powdered nitrate of barytes, and placed in a common
furnace, heated moderately so as to cause the salt to dis-i-
solve in its own water of crystallization. Increase the fire
gradually, and with caution, on account of the considerable
tumefaction that takes place toward the end. When the
mass, which ought then to be of a cherry red, no longer emits
any bubbles, cover the crucible with charcoal to the depth of
an inch or two ; fit on the furnace its dome, furnished with a
plate iron chimney; let it heat thus for a quarter of an
hour; and afterward withdraw the crucible from the fire,
break it, and put the barytes into a close vessel as quickly
as possible.

71bs. produced In this way I lately treated seven pounds of nitrate, which

Slbs 602. of j divided into three common crucibles, and placed in the
pure barytes. r

same furnace. The charcoal expended cost about 30s.

[Is. 3d.]; the decomposition was completely effected in

two hours; and I obtained 3lbs. 6oz. of perfectly pure ba«

Necessary cau- rytes. But it is to be observed, that, if the barytes be kept

tion. too long in the fire after the nitrate is decomposed, it will

become considerably carbonated : and if the quantity be at

all too great, it is impossible, whatever heat we afterward em*

ploy, to deprive it completely of carbonic acid. This is the

whole of the difficulty, which is completely removed, by

acting as I have directed.

F Thus I conceive it is in reiditv more economical, to ex-
Advantages of t

thia mode. tract the barytes from the nitrate by the help of fire, than to
follow the process proposed by Mr. d'Arcet: for even sup-
posing the barytes to be equal in quantity by both processes,
which I have shown cannot be the case, the price of the
potash I must have employed would have nearly doubled

the

ON HIDROGURETTED SULPHURET OF BARYTES. £5

the expense. And as to the purity of the product, since the
washing must be performed very sparingly, I do not see,
that the process of Mr. d'Arcet deserves the preference in
this respect: for it is probable, that the barytes thus ob-
tained will retain a little of the salt of the mother water J
and on the contrary that obtained from the nitrate is ex-
tremely pure, at least if the precaution be taken, before it is
decomposed, to calcine it slightly, and redissolve it, in or-
der to separate a portion of iron proceeding from the suU
phate employed.

VIII.

Remark on the spontaneous Decomposition of the kidroguret*
ted Sulphuret of Barytes : by Messrs. Robiquet and
Chevreul*.

JL N the course of last month, Mr. Robiquet, in order to se- Two sorts of
parate some crystals, that had formed in a phial half filled ^^neo^y
ivith hidroguretted sulphuret of barytes, turned it upside in hidroguret-
down, without uncorking it. Some days after, the weather ^ farv\e&.
having grown colder, the liquor afforded some tolerably large
crystals, which were of a very different figure from those,
that remained at the bottom of the phial. We have exa-
mined these two substances together, and the following are
the results of our observations.

1. The first crystals were elongated prisms. On the ap- 1st, sulphuret
plication of sulphuric acid they gave out sulphurous acid 'etl f luPh^ °£
gas, and at the same time let fall sulphur mixed with sul-
phate of barytes, Hence there could be no doubt, that.they

were sulphuretted sulphite of barytes.

2, The mother water, in which the second crystals had 2d, pure b^
formed, was colourless and very limpid. It retained nei- Jy^'watei
ther sulphur nor sulphurous acid ; had all the characters of

a simple solution of barytes in water; and the crystals com-
ported themselves as the crystals of that earth. They dis-
solved in weak muriatic acid without effervescence, and rn

# Annales de Chimie, yq\. LX1I, p. 180, Mar, 1807.

watep

££) 'PROPERTY OF CAMPHORATED WAT; (Jb

water without leaving any residuum. The latter solution
yielded a precipitate both with sulphuric and with carbonic
acid.
Occasioned by From these observations it was easy to explain the separa-
the phial " t*on °^ tae bidrogtaretted sulphuretof barytes into pure ba-
rytes and sulphuretted sulphite. The oxigen contained in
the pliial, being absorbed by the sulphuret, formed water
and sulphurous acid : but the quantity of oxigen being in-
sufficient, to convert all the sulphuret into sulphite, the
consequence was, that the portion of sulphite which was
formed sulphuretted itself at the expense of the undecorn-
posed sulphuret, and left its base free. The sulphuretted
sulphite, being less soluble than the barytes, of course
crystallized first.
I liclro«u rotted Hence we conclude, that the absorption of oxigen gas by
sulphurets,ab- hidroguretted sulphurets never produces immediately a sul-
nfi always pnate, but a sulphite, notwithstanding the great affinity of
iormsulpliites. the base for sulphuric acid ; as Mr. Berthollet has explained
Sulphite of ba- Jn his Memoir on sulphuretted hidrogen: and that the affi-
phur from ba- n,ty °* sulphite of barytes for sulphur is greater, than that
fy:es« of barytes for the same substance.

IX.

Remark on a Property of Camphorated Water : by C. A*
Cadet, Apothecary in ordinary to his Majesty*.

Carbonic acid ■*■*• Surgeon at a lad rid announced three years ago, that
said to piomote carbonic acid promoted the solution of camphor in water,
camphorTn an<* ^at *ms water nad ver.V decided medicinal properties in
watef, disorders of the bladder. Leaving to the physician to deter-

mine the value of the medicine, I have attempted merely to
confirm the chemical fact.

For this purpose 1 made a solution of camphor in distil-

^ c-^i- i \ led water, and another in water saturated with carbonic acid
evolved j-6 y-»

aerated water after Mr. Paul's method, in order to compare the quantities
**< T?Vr of camphor dissolved. I weighed the camphor before and

• AnnaksdeChimie, vol. LX1I, p. 133, May, 1807.

lifter

■PROPERTY OF CAMPHORATED WATBR. #7

after solution, and I found, that the distilled water had
taken up sixteen grains per quart, and the carbonic acid
only fifteen. As I had been obliged to filter the liquors and Perhaps an er-
diy the iilters, I imagined, that the undissolved camphor j,oration in
must have lost some of its weight by evaporation, and that drying,
the balance did not give me the precise quantity absorbed
by the water. Accordingly I sought for a reagent, that
should acquaint me with the presence of camphor in wa-
ter.

Potash I found would precipitate camphorated water, Pure potash
while neither soda nor ammonia rendered it at all turbid, camphor'from
£ut the potash must be pure and caustic. If it contain car- water, but no
borne acid it no longer precipitates the camphor : and if, °^r a,kali
after it has been precipitated, the vessel be left exposed to
the air, the liquid recovers its transparency by absorbing
carbonic acid.

Here then we have a new method of distinguishing pot- Thisanewust

ash from soda. Camphorated water is in this respect a more Pota?hfrom

certain test than the nitromuriate of platina, and more easily soda.

procured. The metallic salt however is more commodious,

as it precipitates the carbonate of potash,

When employing caustic potash as a test of camphorated Pure Potasn ift
,.,-/, , , . excess precipi

water impregnated with carbonic acid, I obtained no preci- tates it if car-

pitate but by adding a great excess of alkali ; and this pre- bonic acid b*"

. • vj -iiii i present,

cipitate did not appear to me more considerable, than that

obtained in distilled water. I think therefore, that carbonic

acid does not in any sensible degree promote the solution of

camphor in water : and it follows at least from these expe*

riments, that water does not impregnate itself with the

aroma of the camphor solely, as some chemists have be*

lieyed, but that it dissolves a sufficient proportion of this

concrete volatile oil for the purposes of which it is emr

ployed.

If the camphor be reduced to a state of extreme division If the camphor

by trituration with a few drops of alcohol, the water will take alcohol 1 qt/

up more than sixteen grains per quart: some chemists have Yil1 ta/e up

4Jjissohed as far as thirty grains, gai

N ON THE LIMB IN CttEAM OF TARTAR.

X.

Report on a \femoir of Mr. Destouches, Apothecary at Pa-
ris: by Messrs. Vauquelin and Boullay, Read at the.
Parisian Society of Pharmacy, Feb. 1(5, 1S07*.

T:

HE paper, on which these gentlemen were appointed
to make a report, was entitled, a Memoir on the Tartrite of
Lime contained in the Tartarous Acidule.
Tn preparing Preparing Rochelle salt in Quantity, Mr. Destonehes was

unarmed na- desirous of collecting the tartrite of lime, that separates
tron ver^ little » ...

tartrite of lime from cream of tartar at the moment of its saturation, in oi>
found. ^er to turn jt to accoUDt : but he was very much surprised

not to obtain more than two pounds of precipitate at farthest
from about three hundred of cream of tartar, that he had
used, instead of ten times that quantity, which he had rea-
son to expect from the observations of Mr. Vauquelin,
Repeated with The same process repeated afforded Mr. Destouches but
the same eilect. a yery s|jg|lt precipitate, which, confirming the former, in-
duced him to make the following experiments.
Exp. 1. About 1st. To a boiling solution of eight ounces of crystallized
10 oz. of cream car]J0nate 0f soda he added cream of tartar to the point of

01 tartar gave *

1 dr. of tartrite saturation, without any precipitate being produced : but af-

e* ter the solution had stood twenty-four hours, a number of

silky crystals were deposited, which when separated weighed

five drachms. These crystals, being mixed with an excess

of acidulous tartrite of potash, were reduced to one drachm

by washing with boiling water.

Exp. 2. Appa- 2d. A fresh experiment, made with the cream of tartar

iTrs y U employed in the operations in the large way, afforded but two

drachms of precipitate, which were reduced to eighteen

grains by washing with boiling water.

Tartarised na- Surprised by these results, Mr. Destouches conceived,

tron remotes that the tartrite of lime might be dissolved by the Rochelle

the solution of ...

tartrite of lime salt, which prevented it from separating readily. In conse-

ty toiling, but quence he boiled a pound of Rochelle salt and two ounces

it falls down on _ . .

standing. °* tartrite of lime in two quarts or water, when three drachm's

• Annates de Chimie, vol. LX1I, p. 33. April, 18.7.

of

ON THE LIME IN CREAM OF TARTAR. g(J

of the calcareous salt were dissolved; but, after standing
two days, the whole was deposited in a needly form, so as
not to «how an atom of lime on the addition of oxalate of
ammonia.

Whence -could arise thjs difference in the quantity of tar-
trite of lime in different parcels of cream of tartar, which,
according to Mr. Destouches, was ¥V m tne fifst experiment,
and T^ in the second ?

To account for this fact, and ascertain whether, if the Supertartrite
... . n , • i t,,i , , >, P of potash takes

acidulous tartnte of potash contained little or no tartnte ot • gf tor-

lime, it might acquire some in the process of purification, trite of lime by^

the author boiled two ounces of tartrite of lime and eight of ^oili"g theiu

, together.
cream of tartar in eight quarts of water. In this process the

latter retained T\ of its weight of the former.

Mr. Destouches farther satisfied himself of the propor-
tion in which the tartrite of lime unites with boiling water.

Lastly, he concluded from his experiments: General con-:

1st, That the quantity of tartnte of lime in cream of tar- clusions-
tar is liable to vary from the smallest quantity to seven per J^y^^19
cent.

c2dly, That tartnte of lime is soluble in six hundred parts Soluble in 600
of boiling water; and that it is susceptible of a regular cry- Partsof boiling
stallization by being dissolved in a soluble tartnte.

3dly, That, in making Rochelle salt, the solution should In making tar-
be suffered to cool, in order to deprive it of tartrite of tJgbg0j"tj*r°n
lime. should be suf-

4thly, That the carbonate of soda affords the most simple fered tocooL

means of analysing cream of tartar with respect to tartrite SO(Ja test°f

of lime*. lime in cream

of tartar.

Experiments and reflections hy the commissioners. Experiments

1. Six parcels of cream of tartar of the shops, bought at by d^jfuq,Vclm

differeut places, were numbered. A hundred drachms of c. , -

r ' . Six parcels of

each, saturated hot with a solution of pure carbonate of cream of tartar

soda, exhibited towards the end of the saturation a greater 1eft dl^erent

, . & proportions of

or less quantity of precipitate, which separated spontaneous- tartnte ethnic.
ly, but only toward the end of the combination. The so-
lutions, filtered separately, as soon as they were cooled, left
on the filter a substance, part of which was crystalline, part
pulverulent, in the following proportions.

Cream
• See page 32.

50 ON THE LIME IN CREAM OF TARTAR.

Cream of tartar, No. 1

drach. grs.

drach. grs.

1 — 3

No. 4 — 3 9

% — 3 36

5—3 16

3 — 3 4

6 — 2 40

From 2-3 to These different precipitates, which varied from two and

3 5 percent, ^Xf to t^ree an(i j1;ijf per cent, were composed of almost

pure tartrite of lime, soluble, as Mr. Destouches observed,

More left in ' jn about six hundred parts of boiling water. T.*he solution*

solution. of the six sortg of Roc]ielle 8ajt formed, being too dilute for

crystallization, were left to stand for six days. They afji

forded fresh quantities of tartrite of lime, which we. did not

weigh, because the supernatant liquors still afforded a very

sensible precipitate with oxalate of ammonia.

A larger pro- 2. A similar quantity of the cream of tartar No. 6, which

portion obtain* j^ afforded the least portion of tartrite of lime in the pre-
ed by cold so- . r . . *

lution. ceding experiment, was triturated cold with an excess or

carbonate of soda and a little water. Being afterward di-
luted with a sufficient quantity of water to dissolve all the
Rochelle salt formed, it left a residuum of a pulverulent,
insipid matter, a little yellowish, which, when washed and
dried, weighed four drachms and twenty grains. The so-
lution of Rochelle salt formed in this operation was still
precipitable by oxalate of ammonia, eveu after five or six
days.
Tartarised na- 3. A pound of distilled water, boiled with four ounces of

rron took up j^ocjieue 8H|t aiJf] a drachm of calcareous tartrite, dissolved
*ovne in boil-
ing, about twenty grains of the latter, the greater part of which

crystallized on cooling; but the liquor examined at the ex-
piration of six days still afforded unequivocal signs of the
presence of a salt with a calcareous basis.
Vfr. De^tou- This very great difference between our results and those
ehes deceived. annouuced by Mr. Destouches, the much greater proportion
of tartrite of lime which we obtained, and the presence of
this salt in the solutions and mother waters, clearly pointed
out to us, that, deceived by appearances, he did not carry
his researches far enough.
Analysed dif- Jn consequence, without regarding the preparation of Ro-
fereruly. chelle salt, and to find precisely the quantity of tartrite of

lime contained in the specimens of cream of tartar we had

tried,

ON THE I.IME IN CREAM OP TARTAR. 31'

tried, we proceeded in the following manner. A thousand 1000 grs.
grains of each parcel, heated alternately hi a platina cruci-
ble, to dry them without producing* any other alteration,
lost e mally eighteen grains. The heat being increased, till
the complete extrication of the vapours, that announced the
decomposition of the tartarous acid, was accomplished, a
bulky coal remained, of the weight of four hundred and *eft 430 of coat-,
twenty-six or four hundred and thirty grains.

Each coally residuum was diffused in eight ounces of dis- Dissolved in di,
.... • - • <i •• • i #• i • 1 l-i jute muriatic

tilled water, saturated with muriatic acid, or which a slight acij arKj j)rCT

excess was added, and then filtered. Into each of the li- cipitatcd by
... i, ,. . . , . carbonate of

quors, containing the muriates ot lime and potash, a solu- SO(ja

tion of carbonate of soda was poured gradually, till no pre-
cipitate was formed by it.

The precipitates, being collected on dried filters of a Precipitated

known weight, were washed, and afterward exposed for twelve .°.ar °imc °J!
o ■ lime trom oZ

liours in a stove kept at a temperature of 40° or 45° II. [from to 42 grs,
123° to 133° F.]. They were then carbonate of lime in the
following proportions.

grs.

grs.

gr*,

>. 1 — 33

No. 3 — 32

No. 5 — 38

2 — 42

4 — 39

6 — 32

The weight of these carbonates of lime being known, it
remained for us, in order to attain a complete solution of the
question, to reduce them to pure lime, and to learn after-
ward in what proportion this same lime entered into the cal-
careous tartrite to form its basis. With this view we pro-
ceeded as follows.

1. A hundred grains of our calcareous carbonates strongly Carbonate of
calcined left fifty-four of lime in a caustic state, mixed with ,ime contain*
a little oxide of iron in too small a proportion to be calcu-
lated.

2. A hundred grains of tartrite of lime, heated very Tartrite of lime
strongly in the same manner, gave thirty-five grains of a contains"S5«
residuum, that did not effervesce, and was found to be pure

lime.

The first of these two experiments demonstrates, that
lime constitutes fifty- four hundredth parts of calcareous car-
bonate. The second, that the base of tartrite of lime formi

thirty-

<J$ os THE LIME IN CREAM OF TARTAR.

thirty-five hundredth parts of the whole. Consequently the
specimens of cream of tartar, which were the object of our
inquiries, contained the following quantities of lime;

grs. grs. grs.

Proportions of No. 1 — 17*82, No. 3 -*• 17*28, NO. 5 — 2052,
!&£&« S- 81-68, 4-21-08, 6 - l7-38:

and therefore of tartrite of lime ;

gr*. grs. grs.

and hence of No. t — 50*91, No. 3 — 49*37, No. 0 — 58'63,
*a«-trite. g — 61-94, 4 — GO* 17, .6 — 49*37-

General infer- From all these facts we conclude:

fcnces. 1st. That it is true, that the quantity of tartrite of lime

Proportion of varies in different parcels of cream of tartar to be met with
tartrite of lime , , , . j . . . . , , _

from 05 to 07. in the shops : but that this variation does not exceed troni

five to seven per cent, at least in those we had an opportunity

of examining.
"fexists in the 2dly, That it is more natural to look for the source of this
trude tartar, earthy salt in the crude tartar, which contains it ready

formed, than to suppose it produced in the process of puri*

tying it.
Carbonate of 3dly, That the carbonate of soda does not appear by any
testan°ta8°° means calculated for the analysis of cream of tartar with re-.

spect to tartrite of lime.

Tartarised na- 4thly, That in fact Rochelle salt promotes the solution of

iron retains a this calcareous salt with the assistance of heat; and it has
portion. _ _ . , . . .

the farther inconvenience of retaining a certain quantity a

long time in solution.
Khouldbe fiord Sthly, That the Rochelle salt of the shops always con-
from it by cold tains more or less of this earthy salt, and that it ought to be
redissolved in cold water, to obtain it perfectly pure.

6th, That the mode of analysis we employed appeared
to us very proper, to make known precisely how much tar-
trite of lime is contained in the acidulous tartrite of pot-
ash.

XL

ANALYSIS OF T«E PYROPHYSALITE. 3J

XI. •

JSlinercihgical Description and chemical Analysis of a Stone,
called JHyrophysalite : by Messrs. Hisinger and Berze-

LILS*.

JL HE colour of this stone is white, or sometimes of a green- Colour,
ish white, and occasionally small superficial blue 9pots of
filiate of lime may be observed on it.

It is found in masses, forming oblong nodules, most com- Form.
monly of no determinate figure, but sometimes approaching
an irregular rhomboid. Hence no exact measure of its an-
gles can be taken : though apparently its lateral angles are
about 118' and 62° reciprocally.

Its fracture is unequal, foliated and very shining in one Fracture,
direction only, which seems to be that formed by the incli-
nation of 90° or 100° to the axis of the rhomboid. It may
be cleft, though less decidedly, in two other directions
nearly parallel to the sides of the rhomboid. If broken
transversely, it has little or no lustre. The fragments are
of an indeterminate form, angular, with sharp edges, on
which it is a little translucid. They strike fire with steel, Hardness and
and are hard enough to scratch glass easily, but are scratch- gravit>*«
ed by quartz. It is difficult to reduce to powder. Specific
gravity 3*451.

The powder of the purest fragments, projected into a hot Phosphores-
spoon, emit a greenish phosphoric light, that is but of short cent by heat-
duration.

Before the plowpipe without any addition it is nearly in- Before the
fusible: but if the heat be urged to a high degree, it '^SteJSbST*'
ders it white, opake, and its surface is surrounded by small but at a high
bubbles, which issue from it hastily, and burst if the tern- JMj*«*to*A-
perature be kept up. This is a very decided characteristic
appearance, from which the substance has received its
name.

With borax it fuses easily into a colourless transparent Fuses with bo*
glass.

• Annales de Chimie, vol LXVIII, p. 113, May, 1806.

Vol. XIX— Jan. 1808. D Soda

34? ANALVStS OF *HE PYROPHTSALtT*.

Attacked by Soda attacks it with a little effervescence, and produces a
soda.

porous mass.

Where found. This stone was found by Mr. Gahn, at Finbo, near Fah-

lun, about three quarters of a league west of the town, 6ft

the road to Sundborn. The nodules are imbedded in a

granite composed of white quartz, feldtspar, and silvery

mica, the lamina? of which are rhomboidal and in hexagonal

prisms. The nodules are separated from the rock by thin

scales of mica, covered bj^ a talcous substance of a greenish

yellow colour.

Its dfferenre Jt differs from feldtspar, to which it appears to have most

par. resemu]ance> m having but one determinate direction in

which it cau be split, while feldtspar has two. Trie specific

gravity of feldtspar too is but 2*704, and besides it is much

less difficult to fuse.

Analysis. x The following analysis was undertaken conjointly with

Mr. Berzelius.
Powdered. Two hundred grains of pyrophysalite, reduced to fine

powder in a mortar, acquired an increase of weight of four
grains.
Heated alone. a. These 204 grains, having been kept at a red heat in the

fire for three hours, lost 1 '$ grains.
Treated with b. On adding 600 grains of carbonate of potash, and ex-
carbonate of pOS'ulor the mixture to a red heat for three hours in a platina

potash, una • , ,

muriatic acid, crucible, a colourless mass was obtained, perfectly soluble

in muriatic acid. This solution being evaporated to dry-
ness, and diffused in water with a very little muriatic acid,
the silex was obtained, which, after having been washed and
Silex. heated red hot for half an hour, weighed 6(vc25 grains.

Precipitated by c. The sdlutiou in water was precipitated by carbonate of
carbonate of potash, which was added in excess, taking care to keep the
liquor boiling during the process. The precipitate obtained
wag dissolved in caustic potash, except a small portion of a
yellowish powder.
Neither glu- <L To t)m liquor precipitated by carbonate of potash mu-
rine, zircon, ^atic acid was added in excess, and caustic ammonia, with-
noryttria. . , .

out the liquor undergoing any change : a proof, that it con-*

tuined neither glucine, zircon, nor yttria.
Muriat?ofam- «• To the solution in caustic potash muriate of ammonia
nxmiaaddedto was udded, and it was boiled till the ammonia was expelled

ANALYSTS CfF THE PYROPHYSALITE. 35

in vapour. The alumine obtained by this process was care- {^^^
fully washed, and heated red hot. In this last operation,
when the incandescence was carried to a high degree, the
mass emitted fuming vapours; an unexpected phenomenon,
that did not take place at a less elevated temperature. As
we conceived these vapours to be muriate of ammonia, part
of which might have remained in the to ass, it was heated
red hot in the fire full two hours longer. After this the alu- Alumine.
mine weighed 107*5 grains. In another experiment, when
alumine had been exposed to a lower degree of heat, and for
a quarter of an hour only, 116 grains were obtained, which
were reduced to 107*5 by longer calcination. In these ope- An aluminous
rations an aluminous salt was found to attach itself to the
edges of the lid that covered the crucible, but the smallness
of its quantity did not allow us to examine its nature. Ano-
ther time, instead of exposing the alumine to heat, we dis-
solved it in sulphuric acid, and added a little potash ; when
the result was a crystallization of sulphate of alumine,
which continued to the last drop. The sulphuric acid,
in dissolving the alumine, left a residuum of 2 grains of si- Silex.
lex.

f. The yellow powder, which was not attacked by the Yellow re'si-
caustic potash {c), was dissolved in nitromuriatic acid; being duum-
evaporated to dryness, and redissolved in water, a grain and
half of silex were separated from it. By adding to the li- Silex.
quor succinate of ammonia, a precipitate of oxide of iron, Oxide of iron,,
weighing 1*75 grain, was obtained: and on adding caustic
ammonia 1 grain of alumine was precipitated^ The re- Alumine,
nmining liquor being boiled with carbonate of potash, some
carbonate of lime was separated, which, after being heated Lime. x
red hot in the fire, weighed 1*75 grain. This portion of
lime dissolved in weak sulphuric acid without effervescence
forming with it sulphate of liuie.

Thus, if we subtract the 4 grains of silex gained from the Component
mortar in reducing the stone to powder, we find the propor- parts.
tions given by 100 parts of it to be

P2 Al

umiiie

36 ANALYSIS OF THE PYROPHYSALITi:.

Alumine 53*25

Silex 32*88

Lime 0*88

Oxide of iron 0*88

87*89

Loss by calcination '•••'* 0*75

Loss in the analysis 11 *36

100

Loss appeared The last mentioned loss, which we experienced in several

not to proceed trials, led us to suspect the presence of an alkali. In con-

from an alkali. .

sequence we heated the stone with nitrate of barj'tes, dis-
solved in sulphuric acid the mass obtained by this operation,
and poured ammonia into the solution. The saline liquor
being evaporated, and the salt heated red hot in a platina
crucible, we imagined in what remained we discovered traces
of a salt with an alkaline base, mixed with sulphate of lime„
but the quantity of which was too small to ascertain its
weight. It is even probable, that this salt may have been
produced by the reagents. Thus it remained for us to exa-
mine, whether this stone did not contain an acid j as the
fluoric for instance.

Examined for Tn orc|er to determine this, we saturated with muriatic
an a,Ciu. .

acid the liquor that remained after the precipitation of the

earthy substances in the preceding experiments, and then
added muriate of lime. No precipitate however was ob-
tained. We then determined to boil for an hour a portion
of the stone, previously reduced to powder, in sulphuric
acid. Employing a glass retort in this operation, we placed
a vessel filled with lime-water, to receive the gasses, that
should pass over during the solution. None however came
over, except what was contained in the vessels, and the lime-
It contains the water underwent no alteration. We saw however that, the
upper part of the retort and part of the receiver had been
corroded by fluoric acid. This acid therefore actually exists
in the stone, though perhaps in small quantity* or strongly
united with its base. Mr. J. G. Gahn observed a more con-
siderable extrication of it, by treating with sulphuric acid
tUe powder of this stone previously fused with an alkali. In

our

ON SOME CHEMICAL AGENCIES. OF ELECTRICITY. $7

our experiment with nitrate of barytes, this change could

scarcely be perceived. Hence we have still a suspicion, that

the fluoric acid, which adheres strongly to alumine, may have

carried oft' a portion of this earth with it at a high tempera- off^ome^lu-4

ture, as was observed by Mr. Klaproth in his experiments on mine with it.

the topaz. In our experiments therefore there may have been

a loss of both fluoric acid and alumine at the same time.

Finally we conceive the presence of fluoric acid will explain This accounts
that striking emanation of bubbles, which is exhibited by
this stone when exposed to the flame of the blowpipe: it ap-
pears, that part of the acid united to its earthy base produces
a very fusible substance, while another is extricated in the
forms of vapour. This supposition is strengthened by the
observation of Mr. Gahn, that the topaz, particularly that of Topaz emits
Brasil, when exposed to a very violent heat, emits bubbles si- the same'
milar to those produced on the pyropbysalite. As the topaz
contains alumine and silux, with a portion of fluoric acid, we its place
conceive it ought to be placed in a mineralogical view be- amon8 mine-
tween the topaz and the pyenite, which, according to Mr.
Bucholz, contains 0*17 of fluoric acid*.

XII.

On some Chemical Agencies of Electricity, by Humphrey
Davy, Esq. F. R. S. M. R. /. A.

Concluded from Vol. XVIII, p. 339.

V. On the Passage of Acids, Alkalis, and other Substances
through various attracting chemical Menstrua, by Means of
Electricity,

XjSlS acid and alkaline substances, during the time of their Passage of va

electrical transfer, passed through water containing vegetable rious substan"
r ° & & ces through at-

* According to Vauquelin the pyenite, schorlite of Klaproth and
others, schorliform beryl of some, contains but 006 of fluoric acid, 0*60
alumine, 0 SO silex, 002 lime, and 0-01 water. Hauy thinks, that the
pyrophysalite should be considered as a variety of the topaz. Ed.

colours

38 ON SOME CHEMICAL AGENCIES OF ELECTRICITY.

trading chc- colours without affecting them, or apparently combining with
mical mixture* . r . i i ' .• c ■ \ i

by means of them, it immediately became an object of inquiry, whether

electricity. they would not likewise pass through chemical menstma,
having stronger attractions tor them; and it seemed reason-
able to suppose, that the same power, which destroyed elective
affinity in the vicinity of the metallic points, would likewise
destroy it, or suspend its operation, throughout the whole of
the circuit.

An arrangement was made, of the same vessels and appa-
ratus employed in the experiment on the solution of muriate
of soda and sulphate of silver, vol. XVIII, p. 33S. Solution
of sulphate of potash was placed in contact with the negatively
electrified point, pure water was placed in contact with the
positively electrified point, and a weak solution of ammonia
was made the middle link of the conducting chain; so that no
sulphuric acid could pass to the positive pnint in the distilled
water, without passing through the solution of ammonia.

The power of 150 was used: in less than five minutes it
was found, by means of litmus paper, that acid was collecting
round the positive point; in half an hour, the result was Suf-
ficiently distinct for accurate examination.

The water was sour to the taste, and precipitated solution
of nitrate of barytes.

Similar experiments were made with solution of lime, and
weak solutions of potash and soda, and the results were ana-
logous. With strong solutions of potash and soda a much
longer time was required for the exhibition of the acid ; but
even with the most saturated alkaline lixivium, it always ap-
peared in a certain period.

Muriatic acid, from muriate of soda, and nitric acid from
nitrate of potash, were transmitted through concentrated al-
kaline menstrua, under similar circumstances.

"When distilled water was placed in the negative part of the
circuit, and a solution of sulphuric, muriatic, or nitric acid,
in the middle, and any neutral salt with a base of lime, soda,
potash, ammonia, or magnesia, in the positive part, the alka-
line matter was transmitted through the acid matter to the
negative surface, with similar circumstances to those occcu-
ing during the passage of the acid through the alkaline men-
strua j

ON SOME CHEMICAL AGENCIES OF ELECTRICITT. 3Q .

sfrua; and the less concentrated the solution, the greater Pawa?eofva-

nous suostan-
seemed to be the facility of transmission. ces through

I tried in this wav muriate of lime with sulphuric acid, attracting che-

1 mural mixtures

nitrate of potash with muriatic acid, sulphate of soda with bymeansof
muriatic acid, and muriate of magnesia with sulphuric acid; electncity.
I employed the power of 150 ; and in less than 48 hours, I
gained in all these cases decided results; and magnesia came
over like the rest.

Strontites and barytes passed, like the other alkaline sub-
stances, readily through muriatic and nitric acids; and, vice
versa1, these acids passed with facility through aqueous solu-
tions of barytes and strontites; but in experiments in which
it was attempted to pass sulphuric acid through the same men-
strua, or to pass barytes or strontites through this acid, the
results were very different.

When solution of sulphate of potash was in the negative
part of the circuit, distilled water in the positive part, and
saturated solution of barytes ia the middle, no sensible quan-
tity of sulphuric acid existed in the distilled water after 30
hours, the power of 150 being used ; after Jour days, sulphu- ;

ric acid appeared, but the quantity was extremely minute;
much sulphate of barytes had formed in the intermediate
vessel; the solution of barytes was so weak, as barely to tinge
litmus; and a thick film of carbonate of barytes had formed
on the surface of the fluid. With solution of strontites the
result was very analogous, but the sulphuric acid was sensible [
in three days.

When solution of muriate of barytes was made positive by
the power of 150, concentrated sulphuric acid intermediate,
and distilled water negative: no barytes appeared in the
distilled water, when the experiment had been carried on lor
four days; but much oxi muriatic acid had formed in the
positive vessel, and much sulphate of barytes had been de-
posited in the sulphuric acid.

Such of the metallic oxides as were made subjects of expe-
riment passed through acid solutions from the positive to the
negative side, but the effect was much longer in taking place
than in the instances of the transition of alkaline matter.
When solution of green sulphate of iron was made positive,

solution

4(7 OX SOME CHEMICAL AGENCIES OF ELECTRICITY.

F^ssn^o of va- solution of muriatic acid intermediate, and water .negative.

nous substan- , , . . ' T . °

ces through at- ,n lne usual arrangement, green oxide oi iron began to appear

tract>ng che- jn about ttn hours upon the negative connecting amianthus,

roical mixtures , . , •,,,-,

by means of anc* ,n three days a considerable portion had been deposited in

eJecncity. ^he tube. Analogous results were obtained with sulphate of
copper, nitrate of lead, and nitromuriate of tin.

I made several experiments on the transition of alkaline
and acid matter through different neutrosaline solutions, and
the results were such as might well have been anticipated.

When solution of muriate of barytes was negative, solution
of sulphate of potash intermediate, and pure water positive,
the power being from 150, sulphuric acid appeared in about
five minutes in the distilled water; and in two hours the muri-
atic acid was likewise very evident. When solution of sul-
phate of potash was positive, solution o( muriate of barytes
intermediate, and distilled water negative, the barytes ap-
peared in the water in a few minutes; the potash from the
more remote part of the chain was nearly an hour in accumu-
lating, so as to be sensible.

When the solution of muriate of barvtes was positive, the
solution of sulphate of potash intermediate, and distilled water
negative, the potash soon appeared in the distilled water; a
copious precipitation of sulphate of barytes formed in the
middle vessel; but after ten hours no barytes had passed intq
the water.

When solution of sulphate of silver was interposed between
solution of muriate of barytes on the negative side, and pure
water on the positive side, sulphuric acid alone passed into
the distilled water; and there was a copious precipitation in
the solution of sulphate of silver. This process was carried
on for ten hours.

I tried several of these experiments of transition upon ve-
getable and animal substances with perfect success.

The saline matter exposed in contact with the metal, and
that existing in the vegetable or animal substances, both un-
derwent decomposition and transfer; and the time of the ap-
pearance of the different products at the extremities of the
circuit was governed by the degree of their vicinity.

Thus, when a fresh leaf stalk of the polyanthus, about 2

i nches

OK SOME CHEMICAL AGENCIES OF ELECTRICITY. gfi

inches Ion?, was made to connect a positively electrified tube Passage of va.
. . „ ,. - , .- , noussubstan-

contaimng solution oi nitrate ot strontites, and a negatively ces throughat*

electrified tube containing pure water; the water spon be- tractingche-

-• • .• \- r 11 r *• i nncal mixtures

came green, anc^gave indications ot alkaline properties, and by means of

free nitric acid was rapidly separated in the positive tube, electricity.
Alter ten minutes, the alkaline matter wan examined ; it con-
sisted of potash and lime, and as yet no strontites had been
curried into it: for the precipitate it gave with sulphuric acid
readily dissolved in muriatic acid. In haifan hour strontites,
however, appeared ; and in four hours it formed a very abun-
dant ingredient of the solution.

A piece of muscular flesh of beef, of about 3 inches in
length and haifan inch in thickness, was treated in the same
way as the medium of communication between muriate of
barytes and distilled water. The first products were soda,
ammonia, and lime; and after an hour and a quarter, the
barytes was very evident. There was much free oximuriatic
acid in the positively electrified tube, but no particle of
muriatic acid had passed into the negative tube, either from
the muriatic solution or from the muscular fibre.

VI. Some general Observations on these Phenomena, and on
the Mode of Decomposition and Transition.

It will be a general expression of the facts that have been General oh-

detailed, relating to the changes and transitions by elec- servatidns <**
'. .. . ... i • , i , , . the preceding

tricity, in common philosophical language, to say, that hi- phenomena.

drogen, the alkaline substances, the metals, and certain
metallic oxides, are attracted by negatively electrified metal-
lic surfaces, and repelled by positively electrified metallic
surfaces ; and contrariwise, that oxigen and acid substances
are attracted by positively electrified metallic surfaces, and
repelled by negatively electrined metallic surfaces; and
these attractive and repulsive forces are sufficiently ener-
getic, to destroy or suspend the usual operation of elective
affinity.

It is very natural to suppose, that the repellent and attrac-
tive energies are communicated from one particle to another
particle of the same kind, so as to establish a conducting
. chain in the fluid; and that the locomotion takes place in

consequence ;

42 ON SOME CHEMICAL AGENCIES OF ELECT1UCITT.

1 oh' consequence; and that this is really the, case seems to be
the preceding shown by many tacts. Thus, in all the instances in which I
phenomena, examined alkaline solutions through which acids had been
transmitted, I always found acid in them whenever any acid
matter remained at the original source. In time, by the at-
tractive power of the positive surface, the decomposition and
transfer undoubtedly become complete; but this does not
affect the conclusion.

In the cases of the separation of ,the constituents of water,
and of solutions of neutral salts forming the whole of the)
chain, there may possibly be a succession of decompositions
and recompositions throughout the fluid. And this idea is
strengthened by the experiments on the attempt to pass ba-
rytes through sulphuric acid, and muriatic acid through so-
lution of sulphate of silver, in which, as insoluble com-
pounds are formed and carried out of the sphere of the
electrical action, the power of transfer is destroyed. A simw
lar conclusion might likewise be drawn from many pther
instances. Magnesia and the metallic oxides, as I have
already mentioned, will pass along moist amianthus from the
positive to the negative surface; but if the vessel of pnre~
water be interposed, they do not reach the negative vessel,
but sink to the bottom. These experiments I have very often
made, and the results are perfectly conclusive ; and in the
case, page 39, in which sulphuric acid seemed to pass in
small quantities through very weak solutions of strontites
and barytes, 1 have no doubt but that it was carried through
by means of a thin stratum of pure water, where the solution
had been decomposed at the surface by carbonic acid ; for in
an experiment similar to these in which the film of car-
bonate of barytes was often removed and the fluid agitated,
no particle of suLphuric acid appeared in the positive part of
the chain.

It is easy to explain, from the general phenomena of de-
composition and transfer, the mode in which oxigen and
hidrogen are separately evolved from water. The oxigen
of a portion of water is attracted by the positive surf-ice, at
the same time that the other constituent part, the hidrogen,
is repelled by it; and the opposite process takes place at the
negative surface; and in the middle or neutral point of the

circuit,

ON SOME CHEMICAL AGENCIES OF ELECTRICITY. 43

circuit, whether there be a series of decompositions and General ob-
, , . , J . , ,. . , J scrvations on

rerompositions, or whether the particles from the extreme the preceding

points only ore active, there must be a new combination of phenomena,

the repelled matter: and the case is analogous to that of two

portions of muriate of soda separated by distilled water;

muriatic acid is repelled from the negative side, and soda

from the positive side, and muriate of soda is composed ir*

the middle vessel.

These facts seem fully to invalidate the conjectures of M.
Hitter, and some other philosophers, with regard to the ele-
mentary nature of water, and perfectly to confirm the great
discovery of Mr. Cavendish.

M. Ritter conceived, that he had procured oxigen from
water without hidrogen, by making sulphuric acid the me-
dium of communication at the negative surface; but in this
case, sulphur is deposited, and the oxigen from the acid,
and the hidrogen from the water, are respectively repelled;
and a new combination produced.

I have attempted some of the experiments of decomposi-
tion and transfer, by means of common electricity, making
use of a powerful electrical machine of Mr. Nairne's con-
struction, belonging to the Royal Institution, of which the
cylinder is 15 inches in diameter, and 2 feet long.

With the same aparatus as that employed for decomposi-
tions by the Voltaic battery, no perceptible effect was pro-
duced by passing a strong current of electricity silently for
four hours through solution of sulphate of potash.

But by employing fine platina points of— of an inch in
diameter, cemented in glass tubes in the manner contrived
by Dr. Wollaston*, and bringing them near each other, in
vessels containing from 3 to 4 grains of the solution, and
connected by moist asbestus, potash appeared in less than
two hours round the negatively electrified point, and sulphu-
ric acid round the positive point.

In a similar experiment sulphuric acid was transferred
through moist asbestus into water; so that there can be no

* Phil. Trans. Vol. XCI, page 427.

doubt

44 ON SOME CHEMICAL AGENCIES OF ELECTRICITY.

doubt, that the principle of action is the same in common
and the Voltaic electricity*.

VII. On the general Principles of the chemical Changes pro-
duced by Electricity.

General prin- The experiments of Mr. Bennet had shown, that many

ciplcsof the bodies brought into contact and afterwards separated, exhi-

than«res pro- kited opposite states of electricity; but it is to the invest! ga-

duced by elec tions of Volta that a clear deyelopement of the fact is

owing; he has distinctly shown it iu the ease of copper and

zinc, and other metallic combinations; and has supposed that

it also takes place with regard to metals and fluids.

In a series of experiments made in 180lt» on the con*
struction of electrical combinations by means of alternations
of single metallic plates, and different strata of fluids, I ob*
eerved, that, when acid and alkaline solution* were employed
as elements of these instruments, the alkaline solutions al-
ways received the electricity from the metal, and the acid
always transmitted it to the metal ; thus, in an arrangement
of which the elements were tin, water, and solution of potash,
the circulation of the electricity was from the water to the

* This had been shown, with regard to the decomposition of water, by
£)r. Wollaston's important researches.— By carefully avoiding sparks,. 1
"have been able to obtain the two constituents in a separate stale. In an
experiment in which a fine platina point cemented in glass, and con-
nected by a single wire with the positive conductor of this machine, was
plunged in distilled water in an insulated state, and the electricity dissi-
pated into the atmosphere by means of moistened filaments of cotton,
oxigen gas, mixed with a little nitrogen gas, was produced; and when
the same apparatus was applied to the negative conductor hidrogen gas
was evolved, and a minute portion of oxigen and nitrogen gasses : but
neither of the foreign products, the nitrogen gas in the one case and the
nitrogen and oxigen gasses in the other, formed as mush as -jV pait of
the volume of the g^es } and there is every reason to suppose, that they
were derived from the extrication of common air, which had been dis-
ud in the water. This result, which, when I first obtained it in 1803,
aied very obscure, is now easily explained; the alternate products
must have been evolved at the points of the dissipation of the elec-
tricity.

f See Phil. Trans. Vol. XCI, j age 397.

tin,

ON SOME CHEMICAL AGENCIES OP ELECTRICITY. 45

tin, and from the tin to the solution of potash; but in an General prin-.
arrangement composed of weak nitric acid, water, and tin; ehemical

the order was from the acid to the tin, and from the tin to changes pro?
A, ■. ducod by elep*

the water. ... tricky.

These principles seem to bear an immediate relation to
the general phaeuoineua of decomposition and transference,
which have been the subject of the preceding details.

in the simplest case of electrical action, the alkali which
receives electricity from the metal would necessarily, on be-
ing separated from it, appear positive; whilst the acid under
similar circumstances would be negative; and these bodies
having respectively, with, regard to the metals, that which
may be called a positive and a negative electrical energy, in
their repellent and attractive functions seem to be governed
by laws the same as the common laws of electrical attraction
and repulsion. The body possessing the positive energy be-
ing repelled by positively electrified surfaces, and attracted
by negatively electrical surfaces; and the body possessing
the negative energy following the contrary order.

I have made a number of experiments with the view of
elucidating this idea, and of extending its application; and
in all cases they have tended to confirm the analogy in a
remarkable manner.

Well burned charcoal, water, and nitric acid ; the same
substance, water, and solution of soda; made respectively ele-
ments of different electrical combinations, became distinctly
active when L2Q alternations were put together : the positive
energy being exhibited ou the side of the alkali, and the nega-
tive on that of the acid. Arrangements of plates of zinc, pieces,
of moistened pasteboard, and moistened quicklime, to the
number of 40 series, likewise formed a weak electrical pile,
the effect of the lime being similar to that of an alkali, but
the power was soon lost.

I endeavoured, by means of very delicate instruments, to
ascertain the electrical states of single insulated acid and
alkaline solutions, after their contact with metal's ; and for
this purpose I employed at different times the condensing
electrometer of Mr. Cuthbertson's construction, Mr. Ca-
vallo's multiplier, and a very sensible electrical balance, on
the principle of tortion, adopted by M. Coulomb; but the

effects

46 *W SOME CHEMtCAt AGENCIES OF ELECTRIC! TT.

Genera! prin- effects Were unsatisfactory, the circumstances of evaporal ium's

chemteal ' anr* °^ chewed action, and the adherence of the solutions

cha up ■> pro- to the surfaces of the metals employed, in most cast's, piv-

>;. e ee- ven^e(] any distinct result, or rendered the source oi* tin

tiieity doubtful. I shall not enter into any details of these
processes, or attempt to draw conclusions from capricious
and uncertain appearances, which, as we shall immediately
see, may be fully deduced from clear and distinct ones.

The alkaline and acid substances capable of existing in the
dry and solid form, give by contact with the metals exceed-
ingly sensible electricities, which require lor their exhibition
the gold leaf electrometer only with the small condensing
plate.

When oxalic, succinic, benzoic, or boracic acid, perfectly
dry, either in powder or crystals, was touched upon an ex-
tended surface with a plate of copper insulated by a glass
handle, the copper was found positive, the acid negative. In
favourable weather, and when the electrometer was in pet-
feet condition, one contact of the metal was sufficient to pro-
duce a sensible charge; but seldom more than five or six
were required. Other metals, zinc and tin for instance, were
tried with the same effect. And the metal received the posi-
tive charge, apparently to the same extent, whether the acid
was insulated upon glass, or connected with the ground.

The solid acid of phosphorus, which had been strongly
ignited, and most carefully excluded from the contact of air,
rendered the insulated plate of zinc positive by four con-
tacts; but after exposure to the atmosphere for a few mi-
nutes it wholly lost this power.

When metallic plates were made to touch dry lime, stron-
tites, or magnesia, the metal became negative; the effect was
exceedinglv distinct, a single contact upon a large surface
being sufficient to communicate a considerable charge. For
these experiments the earths were carefully prepared; they
were in powder, and had been kept for several da^s in glass1
bottles before they were used : it is essential to the success of
the process that they be of the? temperature of the atmos-
phere. In some experiments which 1 made upon them when
cooling, after having been ignited; they appeared strongly

electrical,

ON SOME CHEMICAL AGENCIES OF ELECTRICITY, 47

electrical, and rendered the conductors brought iii coutact General pnn-
... . . ciples of the

with them positive. chemical

I made several experiments in a similar manner on the changes pro-
effects of the contact of potash and soda with the metals. tricit^
Potash in no instance afforded a satisfactory result; its pow-
erful attraction for water presents an obstacle probably un-
surmountable to the success of any trials made in the free
atmosphere. Soda, in the only case in -which electricity was
exhibited, affected the metal iu the same way as lime, strou- .
titcs, and magnesia. Upon this occasion the soda had been v
prepared with great care, exposed in a platina crucible for
nearly an hour in a red heat, and suffered to cool in the cru-
cible inverted over mercury : when cool it was immediately
removed, and the contact made with a plate of zinc : the
experiment was performed in the open air; the weather was
peculiarly dry, the thermometer stood at 28° Fahrenheit, and
the barometer at 30*2 inches : six contacts gave a charge to
the condensing electrometer in the first trial; in die second
ten were required to produce a similar effect; and after this,
though two minutes only had elapsed, no further result could
be obtained.

In the decomposition of sulphuric acid by Voltaic electri-
city the sulphur separates on the negative side. The expe-
riments of various electricians prove, that, by the friction of
sulphur and metals, the sulphur becomes positive and the
metals negative ; the same thing I lind happens from the
contact of an unexcited cake of sulphur and iusulated me-
tallic plates. Mr* Wilke has stated an exception to lead,
as rendering sulphur negative by its friction. The results
that I have obtained with lead, in trials very carefully made,
are the same as those with other metals*. Sulphur, by be-

* As sulphar is a nonconductor, and easily excited by slight friction,
tor small changes in its temperature, some caution is required in drawing
conclusions from the experiments in which it is employed. Sulphur,
examined immediately after having been heated, gives a positive charge
to conductors, agreeing in this respect with the alkaline substances; and
a slight contact with the diy hand is sufficient to render it negative. In
general likewise in experiments of contact care should be taken that the
metallic plate is free from electricity : well polished plates of copper and
zinc will, I find, receive a negative charge from being laid on a table of
■common mahogany.

ins

4S ON SOME CliEMfCAt AGEKCllSS OF ELECTRICITY.

General pjin. \1](r rubbed or struck against newlv polished lead, always
ctplesof the ' . . __ _,,.., , J ' ,, f ' ,J

chemical became positive. Mr. W like perhaps was misled by using

changes pro- tarnished lead : sulphur, I find, rubbed against litharge, or
iricity. ^a(^ ^ie surface of which has been long exposed to air, be«»

comes negative ; and this exception being removed, all the
, facts on the subject are confirmations of the general princi-

ple*.

On the gpneral principle, oxigen and hidrogen ought to
possess, with regard to the metals respectively, the negative
and positive energy. This I have not been able to prove by
direct experiments of contact; but the idea is confirmed by
the agency of their compounds ; thus I have found, that so-
lution of sulphuretted hidrogen in water acts in the electri-
cal apparatus composed of single pistes and different strata
of fluids, in the same manner as alkaline solutions; and that
solution of oxl muriatic acid is more powerful in similar ar*
rangements than solutions of muriatic acid of a higher de-
gree of concentration ; and- in both these cases, it is impos-
sible to conceive the combined hidrogen and oxigen inactive.
The inference likewise is fully warranted by the case of the
solutions of alkaline hidroguretted sulphurets, which, con-
sisting principally of alkali and sulphur together in union
with water, exhibit the positive energy with regard to the
metals in a very high degree. Tn the series of experiments
on Voltaic arrangements constructed with single plates
above-mentioned, I found the solutions of hidroguretted sul-
phurets in general much more active than alkaline solu-
tions, and particularly active with copper, silver, and lead.
And in an experiment that I made on a combination of cop-
per, iron, and hidroguretted sulphuret of potash, in 1802,
I found that the positive energy of the hidroguretted sul-

* Concentrated solution of phosphoric acid, I find, is decomposed by
Voltaic electricity : the phosphorus combines with the negatively electri-
fied metal, and forms a phosphuret ; at least this happened in the two
cases that I tried with platina and copper. From all analogy it may be
inferred, that the electrical energy of this inflammable substance with
regard to metals is the same as that of sulphur. I tried some experi-
ments of contact upon it, but without success. Its slow combustion in
the atmosphere it is most likely was the cause of the failure: but even
in gasses not containing free or louse' y combined oxigen, its evaporation
would probably interfere.

phuret

ON 80MTB CHCMTCiL AGFiNCirS OF ELECTRICITY. 4<)

phurets with regard to tike copper, was sufficient to m'etv General prin-

power that of the iron : so that the electricity did not circu- 5* !Jg j l fc0

late from the copper to the iron, arid from the iron to the change* pro-

fluid, us id common cases, but from the copper to the iiidro- (lVc'"Hi l>y elec-

tncity.
guretted sulpliiiret, and from the hidroguretted sulphuretto

the iron.

All these details afford the strongest confirmation of the
principle. It may be considered almost as a mere arrange-
ment of facts ; and with some extensions it seems capable of
being generally applied.

.Bodies possessing" opposite electrical energies with regard
to one and the same body, we might fairly conclude would
likewise possess them with regard to each other. This I hare
found by experiment is the case witli lime and oxalic acid.
A dry piece of lime, made from a very pure compact second-
ary limestone, and of such a form as to present a large
smooth surface, became positively electrical by repeated con-
tacts with crystals of oxalic acid : and these crystals placed
upon the top of a condensing electrometer, and repeated!}7
touched by the line, which after each contact was freed from
its charge, rendered the gold leaves negatively electrical.
The tendency of the mere contacts of the acid and alkali
with the metal would be to produce opposite effects to those
exhibited, so that their mutual agency must have been very
energetic.

It will not certainly be a remote analogy to enn-^der the
other acid and alkaline substances generally, and OTigen and
hidrogen as possessing similar electrical relations; and in
the decompositions and changes presented by the effects of
electricity, the different bodies; naturally possessed of che-
mical affinities appear incapable of combining, or of re-
maining in combination, when placed in a state of eieetricity
diHerent from their natural order. Thus, as we have seen,
the acids in the positive part of the circuit separate them-
selves from alkalis, oxigen from hidrogen, and soon; a.;d
metals on the negative side do not nine to oxigen, and
acids do frot remain in union with their oxides; and in this
way the attractive and repellent agencies 'seem to be com-
municated from the metallic surfaces throughout the whole
0f the menstruum.

Vol. XIX — Jan. 1808. E VUI,

50 ON S°M£ CHEMICAL AGENCIES OF ELECTRICITY.

VIII. On the relations between the electrical energies of bo-
dies, and their chemical affinities.
Relations be- As the chemical attraction between two bodies seems to

tween tilt"* dt*f*—

trical energies ^e destroyed by giving one of them an electrical state dif-
of bodies and ferent from that which it naturally possesses ; that is, by-
affinities, bringing it artificially into a state similar to the other, so it
may be increased by exalting its natural energy. Thus,
whilst zinc, one of the most oxidable of the metals, is in-
capable of combining with oxigen when negatively electri-
fied in the circuit, even by a feeble power ; silver, one of
the least oxidable, easily unites to it when positively elec-
trified ; and the same thing might be said of other metals.

Amongst the substances that combine chemically, all
those, the electrical energies of which are well known, ex-
hibit opposite states ; thus, copper and zinc, gold and
quicksilver, sulphur and the metals, the acid and alkaline
substances, afford apposite instances ; and supposing per-
fect freedom of motion in their particles or elementary mat-
ter, they ought, according to the principles laid down, to
attract each other in consequence of their electrical powers.
In the present state of our knowledge, it would be useless
to attempt to speculate on the remote cause of the electric
cal energy, or the reason why different bodies, after being
brought into contact, should be found differently electrified ;
its relation to chemical affinity is, however, sufficiently evi-
dent. May it not be identical with it, and an essential pro-
perty of matter?

The coated glass plates of Beccaria strongly adhere to
each other when oppositely charged, and retain their charges
.on being ^parated. This fact affords a distinct analogy to
the subject; d iferent particles in combining must still be
supposed to preserve their peculiar states of energy.

In the present early stage of the investigation, it would be
improper to place unbounded confidence in this hypothesis;
» . but it seems naturally to arise from the, facts, an,^ to coin-

cide with the laws of affinity, so ably developed Jay modern
chemists ; and -the general application of it may be easily
made.

Supposing two bodies, the particfes of which are in diffe-
rent

ON SOME CHEMICAL AGENCIES OF ELECTRICITY. SI

rent electrical states, and those states sufficiently exalted to Relations be-
give them an attractive lorce superior to the power ol aggre- tri(.al ener„iw
gation, a combination would take place which would be more of bodies and
or less intense according as the energies were more or less af^iesT*"*3;
perfectly balanced; and the change of properties would be
correspondent ly proportional.

This would be the simplest case of chemical union. But
different substances have different decrees of the same elec-
trical energy in relation to the same body: thus the different
acids and alkalis are possessed of different energies with re-
gard to the same metal ; sulphuric acid, for instance, is more
powerful with lead than muriatic acid, and solution of pot-
ash is more active with tin than solution of soda. Such
bodies likewise may be in the same state or repellent with
regard to each other, as apparently happens in the cases just
mentioned ; or they may be neutral ; or they may be in op-
posite or attracting states, which last seems to be the condi-
tion of sulphur and alkalis that have the same kind of energy
with regard to metals.

When two bodies repellent of each other act upon the
same body with different degrees of the same electrical at-
tracting energy, the combination would be determined by
the degree; and the substance possessing the weakest ener-
gy would be repelled; and this principle would aford an
expression of the causes of elective affinity, and the decom-
positions produced in consequence.

Or where the bodies having different decrees of the same
energy, with regard to the third body, had likewise different
energies with regard to each other, there might be such a
balance of attractive and repellent powers as to produce a
triple compound ; and by the extension of this reasoning,
complicated chemical union may be easily explained.

Numerical illustrations of these notions might be made *

without difficulty, and they might be applied to all cases of
chemical action ; but in the present state of the inquiry, a
great extension of this hypothetical part of the subject would
be premature.

The general idea will, however, afford an easy explanation
of the influence of affinity by the masses of the acting sub-
stances, as elucidated by the experiments of M. Berthollet;

E 2 for

5<2 ON SOME CHEMICAL AGENCIES OF ELECTIUCITY.

Relations be- for the combined effect of many particles possessing a feeble

twfccn the elec- , . . , . * . , ,

trical energies electrical energy may be conceived equal or even superior

of bodies and to the effect of a few particles possessing a strong electrical
affinities. * energy: and the facts mentioned, page 38, confirm the sup-
position: for concentrated alkaline lixivia resist the trans-
mission of acids by electricity much more powerfully than
weak ones.

Allowing combination to depend upon the balance of the
natural electrical energies of bodies, it is easy to conceive
that a measure may be found of the artificial energies, as to
intensity and quantity produced in the common electrical
machine, or the Voltaic apparatus, capable of destroying
this equilibrium ; and such a measure would enable ns to
make a scale of electrical powers corresponding to degrees
of affinity.

In the circuit of the Voltaic apparatus, completed by
metallic wires and water, the strength of the opposite elec-
tricities diminishes from the points of contact of the wires
towards the middle point in the water, which is necessarily
neutral. In a body or water of considerable length it pro-
bably would not be difficult to assign the places in which
the different neutral compounds yielded to, or resisted, de-
composition. Sulphate of barytes, in all cases that 1 tried,
required immediate contact with the wire: solution of sul-
phate of potash exhibited no marks of decomposition with
the power of 150, when connected in a circuit of water ten
inches in length, at four inches from the positive point; but
when placed within two inches, its alkali was slowly repelled
and its acid attracted*.

Whenever

* In this experiment, the water was contained in a circular glass ba-
sis two inches deep, the communication was made by pieces of amian-
thus of about the eighth of an inch in breadth The saline solution
filled a half ounce measure, and the distance between the solution and
the water, at both points of communication, was a quarter of an inch.
I mention these circumstances because the quantity of fluid and the ex-
tent of surface materially influence the result in trials of this kind. Wa-
ter included in glass siphons forms a much less perfect conducting chain
than when diffused upon the surface of fibrous nonconducting substances
of much smaller volume than the diameter of the siphons,. 1 attempted
to employ siphons in some of my first experiments $ but the -very great

inferiority

affinities.

ON SOME CHEMICAL AGENCIES oE ELECTRICITY. 53

"Whenever bodies brought by artificial means into a high Relations be-
state of opposite electricities are made to restore the eqiiili- trTcaTener^ies*
brium, heat and light are the common consequences. It is of bodies and
perhaps an additional circumstance in favour of the theory *
to state, that heat and light are always the result of all in-
tense chemical action. And as in certain forms of the
Voltaic battery, where large quantities of electricity of low
intensity act, heat is produced without light; so in slow-
combinations there is an increase of temperature without
luminous appearance.

The effect of heat, in producing combination, maybe easily
explained according to these ideas. It not only often gives
more freedom of uiotion to the particles, but in a number
of cases it seems to exalt the electrical energies of bodies;
glass, the tourmalin, sulphur, all afford familiar instances of
this last species of energy.

I heated together an insulated plate of copper and a plate
of sulphur, and examined their electricities as their temper-
ature became elevated: these electricites, scarcely sensible
at 5()° Fahrenheit to the condensing electrometer, became
at 100° Fahrenheit capable of affecting the gold leaves*
without condensation; they increased in a still higher ratio
as the sulphur approached towards its point of fusion. At
a little above this point, as is well known from the experi-
ments of the Dutch chemists, the two substances rapidly
combine, and heat and light are evident.

Similar effects may be conceived to occur in the case of
oxlgen and hidrogen, which form water, a body apparently
neutral in electrical energy to most other substances: and
we may reasonably conclude that there is the same exalta-
tion of power, in all cases of combustion. In general, when
the different energies are strong and in perfect equilibrium,
the combination ought to be quick, the heat and light in-
tense, and the new compound in a neutral state. This
would seem to be the case in the instance just quoted ; and
in the circumstances of the nnion of the strong alkalis and
acids. But where one energy is feeble and the other strong,

inferiority of effect as compared with that $>f amianthus made me alto-
gether relinquish the ujc of them.

all

5^ ON SOME CHEM|CAL AGENCJES OF ELECTRICITY.

Relations be- all the eilects must be less vivid ; and the compound, instead

tweentheel.ee- of being neutral, ought to exhibit the excess of the stronger
trim energies " n »

of bodies and energy.

«Bnitr CmiC*' TlllS Ia3t k1(>Q is connrmed b)r a11 the experiments, which I
have been able to make on the energies of the saline com-
pounds with regard to the metals. Nitrate and sulphate of
potash, muriate of lime, oximuriate of potash, though re-
peatedly touched upon a large surface by plates of copper
and zinc, gave no electrical charge to them; subcarbonate
of soda and borax, on the contrary, gave a slight negative
charge, and alum and superphosphate of lime a feeble posi-
tive charge.

Should this principle on further inquiry be found to apply
generally, the degree of the electrical energies of bodies, as-
certained by means of sensible instruments, will afford new
and useful indications of their composition.

IX. On the mode of action on the pile of Volta, with experi-
mental elucidations.

Mode of action. The great tendency of the attraction of the different che-»

onVolta's pile, rnlca] agents, by the positive, and negative surfaces in the
with exoeri- . \ . .

mental eluci- Voltaic apparatus, seems to be to restore the electrical equi-
dations, librium. In a Voltaic battery, composed of copper, zinc, and

solution of muriate of soda, all circulation of the electricity
ceases, the equilibrium is restored if copper be brought in
contact with the zinc on both sides: and oxigen and acids,
which are attracted by the positively electrified zinc, exert
similar agencies to the copper, but probably in a slighter de-»
gree, and being capable of combination with the metal, they
produce a momentary equilibrium only.

The electrical energies of the metals with regard to each
other, or the substances dissolved in the water, in the Vol-
taic and other analogous instruments, seem to be the causes
- disturb the equilibrium, and the chemical changes the
se» that tend to restore the equilibrium; and the pheno-
mena most probably depend on their joint agency.

In the Voltaic pile of zinc, copper, and solution of muriate
of soda, in what has been called its condition of electrical
tension, the communicating plates of copper and zinc are in
^>posite electrical states. And with regard to electricities of

such

ON SOME CHEMICAL AGENCIES OF ELECTRICITY. 55

such very low intensity* water is an insulating- body : every Mode of action
copper plate consequently produces by induction an increase with experi- 6>
oi" positive electricity upon the opposite zinc plate; and mental eluci-
every zinc plate an increase of negative electricity on the atlons*
opposite copper plate: and the intensity increases with the
number, and the quantity with the extent of the series.

When a communication is made between the two extreme
points, the opposite electricities tend to annihilate each
other; and if the fluid medium could be a substance inca-
pable of decomposition, the equilibrium, there is every rea-
son to believe, would be restored, and the motion of the
electricity cease. But solution of muriate of soda being
composed of two series of elements possessing opposite elec-
trical energies, the oxigen and the acid are attracted by the
zinc, and the hidrogen and the alkali by the copper. The
balance of power is momentary only ; for solution of zinc is
formed, and the hidrogen disengaged. The negative energy
of the copper and the positive energy of the zinc are conse-
quently again exerted, enfeebled only by the opposing
energy of the soda in contact with the copper, and the pro-
cess of electroinotion continues, as long as the chemical
changes are capable of being carried on.

This theory in some measure reconciles the hypothetical
principles of the action of the pile adopted by its illustrious
inventor, with the opinions concerning the chemical origin of
Galvanism, supported by the greater number of the British
philosophers, and it is confirmed and strengthened by many
lacts and experiments.

Thus the Voltaic pile of 20 pairs of plates of copper and *

zinc exhibits no permanent electromotive power when the
connecting fluid is water free from air*; for this substance
does not readily undergo chemical change, and the equili-
brium seems to be capable of being permanently restored
through it. Concentrated sulphuric acid, which is a much
more perfect conductor, is equally inefficient, for it has little
action upon zinc, and is itself decomposed only by a ver/
strong power. Piles, containing as their fluid element ei-

* The experiments proving this fact, and the other analogous tacts la
this page, may be seen detailed in Nicholson's Journal, 4to, Vol. IV,
I and.'>94; and Phil. Mag. Vol. X, p. 40.

ther

56 ON *<>MF. CIirMTCAL AGENCIES OF ELECTRICITY.

Mode of action ther pure water or sulphuric acid, will undoubtedly give
with expert- ' sul^e shocks, and this effect is connected with the rcstora-
iiitmtal elud- tion of the equilibrium disturbed by the energies of the
metals ; but when their extreme plates are connected there
is no exhibition, as in usual cases of electromotion. Water
containing loosely combined oxigen is more efficient than
Water containing common air, as it enables oxide of zinc to
be formed more rapidly, and in larger quantities. Neutro-
saline solutions, which are at first very active, lose their
energy in proportion as their acid arranges itself on the side
of the zinc, and their alkali on that of the copper ; and I
have found the powers of a combination, nearly destroyed
from this cause, very much revived, merely by agitating the
fluids in the cells and mixing their parts together. Diluted
acids, which are themselves easily decomposed, or which
assist the decomposition of water, are above all other sub-*
stances powerful ; for they dissolve the zinc, and furnish only
a gaseous product to the negative surface, which is imme-
diately disengaged.

There are other experiments connected with very striking
results, which offer additional reasons for supposing the de-
composition of the chemical menstrua essential to the con-
tinued electromotion in the pile.

As when an electrical discharge is produced by means of
small metallic surfaces in the Voltaic battery, (the opposite
states being exalted) sensible heat is the consequence, it oc-
curred to me, that if the decomposition of the chemical
agents was essential to the balance of the opposed electrici-
ties, the effect, in a saline solution, of this decomposition,
and of the transfer of the alkali to the negative side, and of
the acid to the positive side, ought, under favourable cir-
cumstances, to be connected with an increase of tempera-
ture.

I placed the gold cones, which have been so often men-
tioned, in the circuit of the battery with the power of 100,
I tilled them with distilled water, and connected them by a
piece of moistened asbestus, about an inch in length and g.
of an inch diameter ; I provided a small air thermometer
capable of being immersed in the gold cones, expecting (if
iiiy) only a very slight change of temperature; 1 introduced

a drop

ON SOME CHEMICAL AGENCIES OF ELECTRICITY. 5/

a drop of solution of sulphate of potash into the positive Mode of action
, . •••II i i on Vol'a's pile-

Cone: the decomposition instantly began.: potash passed with cxpeii.

rapidly over into the negative cone, heat was immediately mental eluci-*

. , * . . . . . dations.

sensible; and in less than two minutes the water was in a

state of ebullition.

I tried the same thing with the solution of nitrate of ammo-
nia, and in this instance the heat rose to such an intensity as
to evaporate all the water in three or four minute^,, with a
kind of explosive noise; and at last actual inflammation took
place, with the decomposition and dissipation of the greatest
part of the salt*.

That the increase of the conducting power of the water by
the drop of saline solution had little or nothing to do with the
effect, is evident from this crrcumstance. I introduced a
quantity of strong lixivium of potash into the cones, and like-
wise concentrated sulphuric acid, separately, which are better
conductors than solutions of the neutral salts; but there was
very little sensible effect.

The same principles will apply to all. the varieties of the
electrical apparatus, whether containing double or single
plates; and if the ideas developed in the preceding sections be
correct, one property operating under different modifications
is the universal cause of their activity.

X. On some general Illustrations and .Applications of the fore-
going Facts and Principles, and Conclusion,

The general ideas advanced in the preceding pages are GeneraUllus-
evidently directly in contradiction to the opinion advanced by tratlonsand
Fabroni, and which, in the early stage of the investigation,
appeared extremely probable, namely, that chemical changes
are the primui 1/ causes of the phenomena of Galvanism.

Before the experiments of M. Volta on the electricity ex-
cited by the mere contact of metals were published, 1 had to
a certain extent adopted this opinion; but the new facts imt

* In this process ammonia was rapidly given off from the surface of the
negative cone, and nitrous acid from that of the positive cone, and a white
vapour was produced by their combination in the atmosphere above the
apparatus,

mediately

58

OV SOME CHEMICAL AGENCIES 0* ELECTRICITY.

Bttienl i'Ius- mediately proved, that another power must necessarily be*
t rat ions and ' , „ ... »,,'..

applications. concvrntMl ; tor it was not possible to refer the electricity

exhibited by the opposition of metallic surfaces to any che-
mical alterations, particularly as the effect is more distinct in
a dry atmosphere, in which even the most oxidable metals do
not chan.e, than in a moist one, in which many metals un-
dergo chemical alteration.

Other facts likewise soon occurred demonstrative of the
same thing. In the Voltaic combination of diluted nitrous
acid, zinc, and copper, as is well known, the side of the zinc
exposed to the acid is positive. But in combinations of zinc,
water, and diluted nitric acid, the surface exposed to the acid
is negative; though if the chemical action of the acid on the
zinc had been the cause of the effect, it ought to be the same
in both cases.

In mere cases of chemical change likewise electricity it
never exhibited. Iron burnt in oxigen gas, properly con-
nected with a condensing electrometer, gives no charge to it,
during the process. Nitre and charcoal deflagrated in com-
munication with the same instrument do not by their agencies
in the slightest degree affect the gold leaves. Solid pure
potash and sulphuric acid made to combine in an insulated
platina crucible produce no electrical appearances. A solid
amalgam of bismuth and a solid amalgam of lead become
fluid when mixed together : the experiment, I find, is con-
nected with a diminution of temperature, but with no exhi-
bition of electrical effects. A thin plate of zinc, after being
placed upon a surface of mercury, and separated by an insu-
lating body, is found positive, the mercury is negative: the
effects are exalted by heating the metals; but let them be kept
in contact sufficiently long to amalgamate, and the compound
gives no signs of electricity. I could mention a great number
of other instances of pure chemical action in which I have used
all the means in my power to ascertain the fact, and the
result has been constantly the same. In cases of effervescence,
indeed, particularly when accompanied by much heat, the
metallic vessels employed become negative, but this is a phe-
nomenon connected with ctaporation, the change of state of a

body

Otf SOME CHEMICAL AGENCIES OF ELECTRICIT V. £(J

General illus-
trations and
application;,

body independent of chemical change, and is to be referred to General illus-

.. .v , -m trations and

a diflerent law*.

I mentioned the glass plates of Beccaria as affording a
parallel to the case of combination in consequence of the
diflerent electrical states of bodies. In Guyton de Morveau's
experiments on cohesion, the diflerent metals are said to have
adhered to mercury with a force proportional to their che-
mical affinities. But the other metals have different electrical
energies, or different degrees of the same electrical energy
with regard to this body; and in all cases of contact of mer-
cury with another metal, upon a large surface, they ought to
adhere in consequence of the difference of their electrical
states, and that with a force proportional to the exaltation of
those states. Iron, which M. Guyton found slightly adhesive,
I find exhibits little positive electricity after being laid upon
a surface of mercury, and then separated. Tin, zinc, and
copper, which adhere much more strongly, communicate
higher charges to the condensing electrometer: I have had
no instrument sufficiently exact to measure the differences:
but it would seem, that the adhesion from the difference of
electrical states must have operated in these experimentsf,
which being proportional to the electrical energies are, on the

* The cHarigs of the capacities of bodies in consequence of the alter-
ation in their volumes, or states of existence by heat, is a continually
operating source of electrical effects : and as I have hinted, page 47, it
often interferes with the results of experiments on the electrical energies
of bodies as exhibited by contact. It is likewise probably one of the
sources of the capricious remits of experiments of friction, in which the
same body, according as its texture is altered, or its temperature changed,
assumes different states with regard to another body. Friction may be
considered as a succession of contacts, and the natural energies of bodies
would probably be accurately exhibited by it, if the unequal excitation of
heat or its unequal communication to the different surfaces did not inter-
fere by altering unequally their electrical capacities. Of the elements of
flint glass, silex is slightly negative with regard to the metals, the soda is
positive j and in contacts of glass with metals I find it exhibits the excess
of the energy of the alkali: the case, as is well known, is the same in
fiiction, the amalgam of the common machine is essential to its powerfu/
excitation.

f Amalgamation undoubtedly most have interfered; but the genera}
result .seems to have been distinct.

hvpothes's

€0

ON SOME CHEMtCAL AGENCIES OF ELECTRICITY.

General illus-
trations and
applications.

hypothesis before stated, proportional to the chemical affini-
ties. I low far cohesion in general may be influenced or oc-
casioned by this effect of the difference of the electrical ener-
gies of bodies is a curious question for investigation.

Many applications of the general farts and principles to
the processes of chemistry, both in art and in nature, will
readily suggest themselves to the philosophical inquirer.

They offer very easy methods of separating acid and alka-
line matter, when they exist in combination, either together
or separately, in minerals; and the electrical powers of de-
composition may be easily employed in animal and vegetable
analysis.

A piece of muscular fibre, of two inches long and half an
inch in diameter, after being electrified by the power oi 150
for five days, became perfectly dry and hard, and left on in-
cineration no saline matter. Potash, soda, ammonia, lime,
and oxide of iron were evolved from it on the negative side,
and the three common mineral acids and the phosphoric acid
were given out on the positive side.

A laurel leaf, treated in the same manner, appeared as if it
had been exposed to a heat of 500° Or 6*00° Fahrenheit, and
was brown and parched. Gieen colouring matter, with resin,
alkali, and lime, appeared in the negative vessel : and the
positive vessel contained a clear fluid, which had the smell of
peach blossoms; and which, when neutralized by potash,
gave a blue-green precipitate to solution of sulphate of iron;
so that it contained vegetable prussic acid.

A small plant of mint, in a state of healthy vegetation, was
made the medium of connection in the battery, its extremities
being in contact with pure water; the process was carried on
for 10 minutes: potash and lime were found in the negatively
electrified water, and acid matter in the positively electrified
water, v\hich occasioned a precipitate in solutions of muriate
of barvtes, nitrate of silver, and muriate of lime. This plant
recovered alter the process: but a similar one, that had been
electrified for four hours with like results, faded and died*.

The

* Seeds, I find, when placed in pure water in the positive part of the
circuit, geiminate much more rapidly than under common circumstances;

bat

OS SOME CHEMICAL AGENCIES OF ELECTRICITY. 6l

The farts show, that the electrical powers of decomposition ^t"f^as1^ldus"
act even upon living vegetable matter; and there are some applications,
phenomena which seem to prove, that they operate likewise
upon living animal systems. When the fingers, after having
been carefully washed with pure water, are brought in con-
tact with this fluid in the positive part of the circuit, acid
matter is rapidly developed, having the characters of a mix-
ture of muriatic, phosphoric, and sulphuric acids: and if a
similar trial be made in the negative part, fixed alkaline mat-
ter is as quickly exhibited.

The acid and alkaline tastes produced upon the tongue, in
Galvanic experiments, seem to depend upon the decompo-
sition of the saline matter contained in the living animal sub-
stance, and perhaps in the saliva.

As acid and alkaline substances are capable of being sepa-
rated from their combinations in living systems by electrical
powers, there is every reason to believe, that by converse
methods they may be likewise introduced into the animal
economy, or made to pass through the animal organs: and
the same thing may be supposed of metallic oxides; and
these ideas ought to lead to some new investigations in medi-
cine and physiology.

It is not improbable, that the electrical decomposition of the
neutral salts in different cases may admit of economical uses.
^V'ell burned charcoal and plumbago, or charcoal and iron,
might be made the exciting powers; and such an arrangement,
if erected upon an extensive scale, neutrosaline matter being
employed in every series, would, there is every reason to be-
lieve, produce large quantities of acids and alkalies with very-
little trouble or expense.

Ammonia, and acids capable of decomposition, undergo
chemical change in the Voltaic circuit only when the)- are iij
very concentrated solution, and in other cases are merely car-
ried to their particular points of rest. This fact may induce

but in the negative part of the circuit they do not germinate at all.
Without supposing any peculiar effects from the different electricities,
which however may operate, the phenomenon may be accounted for from
the saturation of the water near the positive metallic surface with oxi gen,
and of that near the negative surface with hidrogen,

US

62 ON SOME CHEMICAL AGENCIES Of ELECTRICITY.

mES llldS" us lo il0pe' tnat tne new nl0(le °* wfe8** ma>* leacI us to tfte

applications, discovery of the true elements of bodies, if the materials
acted on be employed in a certain state of concentration, ami
the electricity be sufficiently exalted. For if chemical union
be of the nature which I have ventured to suppose, however
Strong the natural electrical energies of the elements of bodies
may be, yet there is every probability of a limit to their
strength: whereas the powers of our artificial instruments
seem capable of indefinite increase.

Alterations of electrical equilibrium are continually taking
jplace in nature; and it is probable that this influence, in its
faculties of decomposition and transference, considerably in*
lerferes with the chemical alterations occurring in different
parts of our system.

The electrical appearances which precede earthquakes and
volcanic eruptions, and which have been described by the
greater number of observers of these awful events, admit of
very easy explanation on the principles that have been stated.

Beside the cases of sudden and violent change?, there must
be constant and tranquil alterations, in which electricity is
concerned, produced in various parts of the interior strata of
our globe.

Where pyritous strata and strata of coal-blende occur,
•where the pure metals or the sulphurets are found in contact
with each other, or any conducting substances, and where
different strata contain different sahne menstrua, electricity
must be continually manifested; and it is very probable, that
many mineral formations have been materially influenced, or
even occasioned by its agencies.

In an experiment that 1 made of electrifying a mixed solu-
tion of muriates of iron, of copper, oi tin, and of cobalt, in a
positive vessel, distilled water being in a negative vessel, all
» the four oxides passed along the asbestus, and into the nega-

tube, and a yellow metallic crust formed on the wire,
and the oxides arranged themselves in a mixed state round
the base of it.

Fn another experiment, in winch carbonate of copper was

diffused through water in a state of minute division, and a

~.tive wire placed in a small perforated cube of zeolite in

the

Mcfwkong JfiOos. Journal- VMHr.pl Jl.p.tt.

Fig.*.

Fig. 3.

Fuj.4.

ON SWEAT AND ITS ACID. 63

the water, green crystals collected round the cube; the parti- General illus-

, ' , , s trations and

cles not being capable of penetrating it. application*.

By a multiplication of such instances the electrical power
of transference may be easily conceived to apply to the ex-*
planation of some oi the principal and most mysterious facts
in geology.

And by imagining a scale of feeble powers, it would be easy
to account for the association of the insoluble metallic and
earthy compounds containing acids.

Natural electricity has hitherto been little investigated, ex-
cept in the case of- its evident and powerful concentration in
the atmosphere.

Its slow and silent operations in every part of the surface
will probably be found more immediately and importantly
connected with the order and economy oi nature; and inves-
tigations on this subject can hardly fail to enlighten our
philosophical systems of the Earth; and may possibly place
new powers within our reach.

Explanation of the Figures,

PL I. Fig. 1, Represents the agate cups, mentioned VoL
XVIII, p. 323.

Frg. 2, Represents the gold cones, page 325.

Fig. 3, Represents the glass tubes, and their attached
apparatus, page 337- ,

Fig. 4, Represents the two glass tubes, with the interme-
diate vessel, page 338.

In all the figures A B denote the wires, rendered one posi-
tively, the other negatively electrical; and C the connecting
pieces of moistened amianthus.

-*-■■ '- -■ ■■■:.'■■■ ■ ■■■ —, — -

XIII.

Memoir on the Analysis of the Sweat, the Acid it contains, and
the Acids of the Urine and Milk; read to the National In-
fiitute by Mr. Thenard*.

F we examine the principal fluids of the animal economy, Animal flunk
hat some are alkaline, and the others acid.

Annales de Chimie, vol. L1X, p. 262, Sept. 1S06.

we find, that some are alkaline, and the others acid. To the ?Cid °' alku

' line.

first

(>£ ON SWEAT AND ITS ACID.

first class belong the blood and bile: to the second, the
urine, milk, and sweat!

Hence arise naturally two questions; what are the alkalis,
and what are the acids, proper to these fluids ? The first lias

S<xTa i the only a]pea(jy ^een solved, as the researches of Cadet and Deyeux
have proved, that we never meet with any alkali but soda in

What are the animal substances. The solution of the second however is
but little advanced : even the data, that might lead to it, are
for the most part inaccurate: and many of the results relat>
ing to some of these parts are too deficient in proof, to be
placed in the rank of demonstrated truths. This is the
question therefore, that will form the subject of the present
memoir; and, that I may treat it in a manner suitable to
the object I have in view, I shall tirtt present as full aq ana-
lysis of the sweat, as we have of urine and of milk.

Part I. Of the Sweat.

Sweat. The sweat is a fluid separated from, the blood in the skin

by exhalant vessels, with which its texture is traversed or
filled. It is more or less copious in different individuals:
and its quantity is perceptibly in the inverse ratio of that of
the urine. All other circumstances being similar, much

That of an more is produced during digestion than dnring repose. The

adult from maximum of its production appears to be twentv-six "rains

1S20 grs. near ' , . , . F . , • • • * •

2 lbs. avoivd., and two thirds in a minute, the minimum nine grains, troy

to 58400, near weight. It is much inferior however to the pulmonary tran-

M lbs. per day. . n . " . . V1 ' , *\

r.r, c , spiration: and there is likewise a great inherence between

i hat from the P p ' .

luuns still their nature and manner of formation. Ihe one is the pro-

*n"re« duct of a particular secretion, similar in some sort to that

crvtloa"1 a **' °f tne urme: tne Other* composed of a great deal of water
and carbonic acid, is the product of a combustion gradually
effected by the atmospheric air.
Ir quarries. The sweat, in a healthy state, very sensibly reddens litmus,

paper or infusion. In certain diseases, and particularly in
putrid fevers, it is alkaline: yet its ta*te is always rather sa-
line, and similar to that of salt, than acid. Though colour-
less, it stains linen. Its smell is peculiar, and insupportable
when it is concentrated, which is the case in particular during
distillation. But before I speak of the trials to which I sub-
jected it, and for winch 1 had occasion for a great quantity,

I

ON SWEAT AND ITS ACID. 65

I ought to mention the method I adopted for procuring
it.

I applied to persons who are in the babit of wearing flan- How obtained
ml waistcoats next the skin. To avoid every source of y
errour, the waistcoats, before they were put on, were first
washed with soap; then rinsed in a stream of water, and af-
terward in diluted muriatic acid several times; and lastly
thev were immersed and wrung out of a large tub of water.
The persons who were so obliging as to submit to the expe-
riment, went into the bath before they began it, and were
:ularly careful to rub every part of the body well. The
sweat that was collected uninterruptedly in the flannel dur-
ing the course of ten days I separated by means of hot dis-
tilled water; and this I boiled down to the consistence of a Distilled.
sirup in a retort, to the neck of which a receiver was adapted.
The product of this distillation emitted a nauseous smell,
which diminished as the liquor cooled. It caused no alteration
in sirup of violets, but it evidently reddened infusion of lit-
mus. Left for some time exposed to the air, it retained the
transparency it had at first, and underwent no remarkable
change, unless with respect to its smell, which entirely
vanifhed : in a close vessel probably it would have putrified,
like the product of the distillation of all other animal fluids,.

The residuum was not very copious, and evidently void of Residuum
smell ; though pretty strongly acid, the agreeable taste of
eea salt predominated in it, yet with this taste something
acrid and pungent was perceptible; it was slightly deliques-
cent, requiring some days to resolve into a liquid; and it was
completely soluble in water. Lime, barytes, ammonia, the
acidulous oxalate of potash, the carbonates of potash and
soda, most acids, and acetate of lead, gave no precipitate
with this solution, and disengaged nothing from it. Nut-
occasioned a slight precipitate in it, but the nitrate of
« r rendered it very tuvbid.

tJalciued by if self it was decomposed, emitting vapours Calcined,
that had nothing of the. fetid smell of animal matter, and
was converted into a black substance, that was composed
*imply of a great deal of common salt, charcoal, and scarcely
. perceptible quantities of lime and oxide of iron.

Finally, when subjected to calcination after the acid has Calcined aftar
Vol. XXIX.— Jan. 1S0S. F been

66

saturation with
potash.

Contains com-
mon salt, very
little phos-
phate of lime,
oxide of iron ,&
animal matter,
and an acid.

This probably
the acetous.

Yet it might be
a new acid.

Positive proof
to be sought
where practi-
cable.

Th one/id ob-
tained se-
parate.

fa properties;

ON SWEAT AND ITS ACII*.

been saturated with potash, this base was obtained in the
state of carbonate, beside the preceding matters, in the black
substance remaining.

These trials already convinced me, that sweat contains
muriate of soda, traces of phosphate of lime and oxide of
iron, very little animal matter, no sulphate, no soluble phos-
phate, and in addition an acid, the nature of which I already
suspected.

In fact this acid, combined with a base, giving rise to st
carbonate by its calcination, must belong to the vegetable or
animal kingdom ; and as besides it was volatile, and formed
soluble salts with the different salifiable bases, it became
very probable that it was the acetous acid.

Led by this reasoning to suppose the existence of acetous-
acid in sweat, I still required possitive experiments, to con-
vince myself of it: for though the properties I have menti-
oned belong only to the acetous, of all the known acids, yet
they might equally belong to an unknown acid. Thus azote
is far from being sufficiently characterised by the properties*
with which we usually content ourselves as denoting its pre-
sence; namely, it^being without smell, without colour, and
without action on blue colours or solution of lime; all nega-
tive properties, and far from being as characteristic as those,
which, being founded on combinations, maybe termed posi-
tive. Farther, to give certainty, there must be a combina-
tion of these positive properties, unless some one, which hap-
pens in certain instances, be so decisive, as to suffice of
itself.

Thus, though every thing apparently tended to show me,
that the acid of sweat was the acetous, it was neceffary for
me to obtain it separate, and combine it with different sub-
stances, before I would pronounce definitively on its nature.
This I effected easily, by distilling with another acid the re-
siduum, tvhich a certain quantity of sweat collected in a flan-
nel waistcoat slightly alkaline afforded by evaporation. In
this distillation I preferred the phosphoric acid ; on one hand,
because it is fixed ; and on the other, because as it is very difi-
cult to decompose, it acts less on organic matters than many
others. I farther took every precaution, to condense the
product of distillation in the receiver. This product strongly

reddened

ON URINE AND ITS ACIDS* ($J

te.Mened infusion of litmus: its taste was that of a weak-
aeid: its smell that of vinegar: combined with potash it
formed a salt, which by evaporation was reduced to little
Wiihing scales, micaceous as it were, acrid, and very deli-
quescent: on the addition of sulphuric or phosphoric acid
this salt evolved a strong smell of acetic acid; and, poured
into a solution of nitrate of mercury, it precipitated crystal-
line scales, similar to accetite of mercury.

This acid therefore was the acetous, and consequently hu- This acid the
man sweat is formed of a great deal of water f free acetous acetous«
acid; muriate of soda; an atom of phosphate of lime and
oxide of iron ; and an inappreciable quantity of animal matter, The animal
which approaches much nearer to gelatine than to any other S^XunT
substance.

Part. IT. Of the acids of urine.

These acids are, 1st, the uric acid, which frequently gives Urine contain*
Vise to the stone in the bladder: 2dly, thebenzoic acid, which s0mtt\mQs
exists very rarely in that of adults or old persons, and is benzoic, and a
tnore frequent in that of infants : 3dly, we are obliged to ad* thl '
mit another acid, since the urine strongly and constantly
reddens tincture of litmus, an action which cannot be
ascribed either to the uric acid, that does not alter its colour,
i>Y to the benzoic acid, that is found in the urine only un-
der certain circumstances, which are not yet well known.

What is this new acid? This is the second question that I whatisthitj
shall attempt to discuss. At present it is generally supposed acid?
to be the phosphoric acid. This opinion is grounded on the Supposed to be
presence of a pretty large quantity of phosphate of lime in phosphoric.
urine, which, being itself insoluble when neutral, becomes
very soluble and even deliquescent, when it is with an excess
of acid : and at the same time it is strengthened by the con-
sideration, that beside the phosphates of lime, soda, amtno-
nia, and magnesia, we find nothing in urine but the sulphates
of potash and soda, and muriates of soda and ammonia,
neither of which salts is decomposed by the acidulous phos-
phate of lime: their acids therefore, that is the sulphuric
and muriatic, cannot exist in the urine, sine^ as is well
known, they would convert the phosphate of lime into aci-
dulous phosphate of lime. If then the phosphoric acid be
X F 2 not

(Jg ON URINE AND ITS ACIDS.

not the solvent of the phosphate of lime in urine, it must
undoubted ly be some other weak acid, and probably an acid
of the nature of the vegetable and animal acids.
This probably Nothing- in fact proves, that this is not the case. I will
a mistake. venture to say farther, that this hypothesis appears to me
more admissible than the former: for, to admit the acidu-
lous phosphate of lime in urine, we must suppose, that a
portion of one of the phosphates of the blood is decomposed
in the kidneys, when it reaches them: that the phosphoric
acid is free, or at least constitutes an acidulous phosphate
with the phosphate of lime, though present with the soda of
the blood, and with the base of the phosphate decomposed,
both of which appear not to enter into any new combination
at the time, and which are taken up with the residuum of the
secretion by the venous system, to be returned into the cir-
culation.
In the living It is true it may be said, that bodies under the influence

action0 ma" be °lf ^e act m a different manner from what they do when de-
restrained, pvived of it ; and that consequently decompositions may take
place in the animal economy contrary to all that we are ac-
quainted with. But, beside that this answer, though accu-
rate, proves little in favour of the case in question, it may
be employed in a certain degree to retort the argument, as
thus: we have no avowed instance of salts being decom-
posed in the animal economy so that their alkali and acid re-
main present together without combining, while on the other
hand it is demonstrated, that animal substances, particularly
those that exist in the blood, as the fi brine and albumen, are
transformed into some other in passing through this or that
organ; thus in the mammary glands they are converted into
sugar of milk, and the caseous, butyraceous, and extrac-
tive matters; and in the kidneys they form uree, uric acid,
and sometimes benzoic acid. Now if they constantly form
one of these acids, and sometimes the other likewise, it is
possible they may form a third, which combines with the
phosphate of lime, and holds it in solution. Such were the
reflections that have led me to examine the acid of urine;
and I shall proceed to relate the experiments, that I have
made to discover its nature*

After having employed several means, which I shall pase

over,

ON URINE AND ITS ACIDS, 69

over, as they were without success, at least directly, I cvapo- Urtye evapora-
. , J . . .. , .» .. . a • VA _ A j U:<i continued

rated almost to dryness, in a water-bath, that I might not de- an acid>

compose the urce, about twenty quarts of fresh urine. The

residuum powerfully reddened infusion of litmus; and I

treated it cold, at several times, with a great deal of alcohol

at 36° of strength.

I thus dissolved the greater part of the acid; but T could This separate!
_. „ .. ••«-:, i • f i i -i i'i ureat part.

not effect its complete solution, whatever quantity of alcohol

I employed, and even by the assistance of a small degree of
heat. Having mixed all the liquors, I concentrated them by
evaporation at a low temperature. I then examined the mat- Examined.
ter, which I had afresh reduced toasirupy consistence. First
I diluted a portion with water, and added to it lime-water and
ammonia. No precipitate took place, or at least it was so
slight, that it did not appear till long after the mixture was
made. Another portion I calcined. The residuum was not
only not acid; but, even treated with water, the calcareous
salts and lime-water, added to the solution, gave no indica-
tion of an atom of phosphate. That which was not dissolved,
and which contained a great deal of coal when completely
incinerated, merely left a few traces of phosphate of lime.

Hence it should seem, that urine contains, beside the uric It has at least
., •■,'•, -. * • i-it, i a f)»naiv radi-

acid, an acid with at least a binary radical. I strongly sus- ca| '

pected, that it was the acetous; because I had already found
this acid in other animal fluids, it exists in almost all vegeta-
bles, and it is formed in almost all the decompositions, that
organized bodies undergo. In consequence into the portion Barytas added,
I had left containing the acid T poured barytes-water. Hav-
ing then evaporated the mixture to dryness, still with a gentle
heat, I treated it afresh with alcohol, which dissolved the
whole, except a yellowish powder, that was true acetate of

barytes. '11ms from this experiment we may infer, that f°riTl<:'c' acetate
. * . .,.-,,., , offaarytes.

there is acetous acid m urine ; though it does not prove, that

there is no phosphoric acid, since urine evaporated by a water-
bath, and treated with a great deal of alcohol, always leaves
a slightly acid residuum, and this acid, it may be said, is the
phosphoric.

To demonstrate, that this acid is not really the phospho- Attempt to
ric, I could not have recourse to calcination ; for the resi- prove, that it
duutn, containing phosphate of ammonia, could not have c

failed

70 ON URINE AND ITS ACIDS.

fee phospho- failed to yield phosphoric acid : I was under the necessity

ric acid. . ., _

therefore of adopting the synthetical method. Accordingly
after having saturated by means of potash the extract of
some urine, thnt I had evaporated to dryness with the pre-
; cautions already described, I poured in a little vinegar,
treated it with alcohol, and obtained the same results us {
have already related; that is to say, the portion, that was
not dissolved after repeated affusions of alcohol, was acid.
This proof, I am aware, may still be questioned : for, if the
phosphoric acid existed in the urine, it would be partly re-
tained by the salts present in it, in the same manner as the
acetous, and would become insoluble in alcohol. But if it
be considered, that the existence of the acetous acid in
urine appears certain*; that nothing demonstrates the pre-
sence of the phosphoric; that the greater part of the free
acid of the urine evaporated to the consistence of a sirup
dissolves in alcohol; and that all this acid, thus dissolved, is
the acetous : lastly, if we recollect, that the residuum is
slightly acid ; and that, if saturated with potash, afterward
acidulated with vinegar, and treated afresh with alcohol, it
remains equally acid: all these circumstances compared to-
gether, I conceive, will acquire such a degree of certainty,
as absolutely to convince us, that it is the acetous acid alone
in Urine which dissolves the phosphate of lime, and which
alone too most commonly imparts to it the property of red-
dening infusion of litmus.
Farther proof But, to render this last conclusion still more evident, X
that it is the ought to demonstrate, more directly than has hitherto been
done, that the benzoic acid is not in fact a constant princi-
ple of urine. For this, instead of employing sublimation
with or without an excess of another acid, when the urine
is reduced to a sirupy consistence; a method always inaccu-
rate, since the benzoic acid combined with ammonia is car-

* I believe, that, in the evaporation of the urine in a water hath, a
little litee is decomposed, and that ammonia, and peihaps a little ace-
tous acid is formed. Supposing this to he the ease, it still remains very
probable, that the acid of urine is the acetous acid, and r*ot any other :,
for in favour of this opinion 1 might not only adduce the reasons that
have been, or that will be given, but even the tendency the uree would
have in this case to be converted into acetous acid.

ried

ON URINE AND ITS ACIDS, 71

ricd off more of less with the water that rises in vapour ; I
added lime before I began the evaporation, and treated the
extract with alcohol. >.

It is true by this method we dissolve, beside the benzoate
of lime, some uree, muriate of ammonia, and soda, and
acetous acid : but if the alcoholic solution be converted into
a concentrated aqueous solution, the acids added afterward
will soon manifest the presence of benzoic acid, if there be '
ever so little in the solution.

Thus, when we would analyse urine, the benzoic acid Mode of ana-
should be first sought for, either by this or some analogous y!>m8 UI
process. If by this we discover no trace of it in the liquid,
which is most commonly the case, we may conclude, that it
does not contain any sensible quantity of it : then, after
having evaporated another portion of the urine in a water-
bath, and thus ascertained the quantity of water that enters
into its composition, the residuum must be treated repeat-
edly with alcohol at 36*: thus we shall dissolve the uree, the
muriate of ammonia, some muriate of soda, and the greater
part of the acetous acid.

The mixture of these different substances should be di-
vided into thfee portions. From the first the acetous acid
is to be separated by the means pointed out. From the se-
cond the uree is to be extracted by concentrated nitric acid,
from which again it is to be separated by the carbonate of
potash and alcohol*. Lastly, from the third part the quan-
tity of sal ammoniac and muriate of soda is to be ascer-
tained by sublimation. In this sublimation the uree is de-
stroyed, the acetous acid is volatilized, the muriate of soda
remains behind, and is to be weighed : the -sal ammoniac
sublimes, and is to be collected ; and as it is always mixed
with black matters, and may besides contain a little carbo-
nate of ammonia, it is to be purified by dissolving it in wa-
ter and evaporating the solution.

The matters contained in urine, that are soluble in alco- Soluble mat-

* Pure uree does not crystallize : it is only when combined with eer Uree does not

tain salts, which frequently happens, that it forms crystals. I believe, cryntallije

but I am Hot ceitain, that it renders several salts soluble in alcohol, u.1. 0ul *

, . , , , „, addition of

winch when alone arc insoluble in it. This might easily be verified with gomeaalt.

muriate ©f baryte**

hol,

yS ON THE ACID OF MILK.

tcrs contained hoi, are five; namely, acetous acid, benzoic acid, muriate
of ammonia, muriate of soda in part, and uree. These that
are insoluble in it are more numerous, as at least eight may
be reckoned ; namely, four phosphates, two sulphates, mu-
riate of soda, and uric acid. On treating with water these
eight substances insoluble in alcohol, we dissolve the phos-
phates of soda and ammonia, a very little phosphate of
magnesia, the muriate of soda, the sulphates of potash and
soda, which are known by their crystallization, and which
may be separated from one another in a certain degree by
solutions of platina. We may judge that phosphate of mag-
nesia is present by means of potash, which will precipitate a
small quantity of this earth.

The substances insoluble in water then are the phosphate
of lime, some phosphate of magnesia combined with phos-
phate of ammonia, and uric acid, which may be separated
in the usual way. This method however differs very little
from those that have been given by other chemists ; and I
describe it here in a concise manner, because it is intimately
connected with my subject.

Part III. Of the acid of milk.

Milk quite Milk as soon as it comes from the mammary glands red-

fresh contains dens litmus paper: it contains therefore a free acid. AVhen
I discovered this fact near eighteen months ago, I endea-
voured in vain to obtain it pure* in order to examine its pro-
perties I and all my endeavours since that time, to attain the
same object, have been equally fruitless.
Probably the Though every thing leads us to believe, that it is the ace-
acetous. tous aci,^ yet it is the same with respect to it, as with re-
spect to the acids of sweat and urine: to pronounce decidedly
on its nature, it was necessary to separate it, and combine
it afterward with salifiable bases. This at length I effected,
by pursuing a method analogous to that, which enabled me
to obtain the acid of urine. 1st, I evaporated the milk to
dryness: 2dly, T treated the residuum with barytes water,
to saturate the acid: 3dly, I evaporated to dryness again:
4thly, I treated it with alcohol, to dissolve in part the ex-
tractive matter, and particularly to collect the caseous sub-
stance, so that none should remain suspended in the water:

5thlv,

This j roved.

ON THE ACID OF MILK. 73

5thly, I macerated in water what was not dissolved by the
alcohol, filtered the liquor, concentrated it by evaporation,
and distilled it with phosphoric acid. By these means I col-
lected in the receiver a fluid, which possessed all the proper-
ties of acetous acid.

It follows then, from the various experiments I have de- General con-
scribed, 1st, that urine probably contains no free phosphoric
acid* but that there is to be found in it, as well as in the
milk and sweat, acetous acid. 2dly, That the sweat con-
tains, beside this, a great deal of water, some muriate of
soda, a small quantity of animal matter, and some traces of
oxide of iron and phosphate of lime.

It is probable, that the acetous acid exists in several other Acetous arid

substances. Several observations lead me to believe, that probabiy1ex!st3

' . in several other

it would be found in cantharides: the analogy of thebombic substances,
and formic acids with vinegar have already been suspected :
and I would almost venture, to generalize this idea, and say,
that it exists in almost all animals, as in the sap of almost perhaps in
all vegetables: at least we may affirm, that of all the acids
its formation costs nature least; its principles having such a Most easily
tendency to unite, that we can scarcely ever disturb the *ormed-
equilibrium of the molecules of organized substances, with-
out producing more or less of it. If the decomposition be
rapid, acetous acid is formed; if slow, it is formed still:
Avitness the distillation of vegetable and animal substances,
their treatment by nitric and by oxigenized muriatic acid,
their spontaneous decomposition, and their transformation
into vegetable mould oradipocire.

In cases of indigestion it is known, that the food becomes Formed in iu~
ncid, and this too is owing to acetous acid. In several cir- d,Sestl0U'
cumstances however, its production has not yet been tho-
roughly appreciated : it remains to be seen, whether it exist Farther inqui-
in the milk of all kinds of animals; whether it be found in riesi,,tended*
the sweat of all, and whether the sweat of different animals
be identical; and lastly, whether it be not in the state of
acetate in such urine as is alkaline. This is an inquiry which
I propose to undertake, and the results of which 1 shall sub-
mit to the judgment of the Institute, if they prove worthy
its attention.

XIV.

*>W ORPIMENT AND REALGAR.
XIV.

Remarks on Orpimcnt and Realgar: by Mr. Thenard*.

?XZT mid "RPIMENT and realgar are two ores of arsenic sum-,
ciently abundant. The first is almost always in the form of
laminae of a pure yellow colour; and the second is as gene-
gaid to be the rally a red mass more or less brown. Bucquet asserted, that
of arsenic mo- these compounds were formed of oxide of arsenic, and sul-
difiedby heat; phur, in the same proportions, and ascribed their difference
of colour to the different degree of heat employed in pre-
thensulphurot- paring them. Bergman likewise admitted the oxide of ar-
fering m 'their semc» as well as sulphur, in both ; but he imagined they
proportions j differed in colour because they contained different propor-
tions. These opinions, supported by some experiments that
were capable of deceiving, prevented chemists for some time
fjjom forming a decided opinion: that of the Swedish che-
mist however prevailed, and since the creation of the new
theory, and the reform of chemical language, orpinient and
realgar are described in chemical treatises under the names
of yellow sulphuret of oxide of arsenic, aud red sulphuret-
and lastly ted oxide of arsenic. Nevertheless some have lately thought,
d£en?ox-f that these two substances differed less with respect to their
ides. proportions of sulphur, than those of their oxigen.

Thus it has been successively supposed, 1st, that orpiment
and realgar were hornogeneal compounds containing burned
arsenic: 2dly, that they were oxides more or less sulphuret-
ted: and 3dly, that they were oxides more or less oxided, m
well as more or less sulphuretted.
AT-^montsfor The partisans of the first opinion ground it on the fact,

the first opi- \\m\ by heating equal quantities of arser.ious acid and sul-
ttion. i i i •

phur in a less or greater degree the product is sometimes or-
piment, at others realgar: therefore say they, if their colour
differ, it is owing to the heat, which occasions a different ar-
rangement of their particles.

* Annates de Chimic, vol. L1X, p. 284, Sept. 1806. This paper was
read to the Phdomathic Society about a year ago.

Those

OJif ORPIMENT ATfD REALGAR. /,>

Those of the second refer to the analysis of orpiraent and For the second
realgar in the humid way. As they obtained from the lat-
ter much more oxide of arsenic, and less sulphur, than from
the former, their conclusion appeared to them just.

Those of the third argue from analogy. They imagine, For the tlurJ.
that, when a metallic solution is precipitated by a hidrosul-
phuret, the sulphuretted oxide that i$ formed is always of
the colour of the oxide it contained.

It is easy to perceive, that none of these reasonings are All liable to
free from objection : and hence I have imagined it would not
be useless, to subject both orpiment and realgar to a fresh
examination, in order to tind with precision how they differ
from each other.

But before I speak of the experiments however, which I promt says,
have made with them, I ought to quote what prof. Proust that» in Pre*

o • -i t i i i-ki i -%,-r t txr paring orpi-

says or orpiment in the Journal de Physique, vol. XL1X, ment

pp. 411, 412: particularly as I am perfectly of his opinion

respecting the nature of this compound.

" Things happen differently," says Mr. Proust, " when,

instead of applying potash to the sulphuret of antimony,

we add it to the ore of arsenic : the sulphuretted hidrogen,

that is formed while the arsenic becomes oxided, does not

adhere to this oxide, on precipitating it with an acid, as

happens to that of antimony. The hidrogen acts a very the oxide of

different part during this precipitation : it is employed in a'-smcisdc-
,. • ,. , ? ' . v , . , . comnosedbr

disoxidmg the arsenic, in order that it may attach itself as the hidrogen,

a metal to the sulphur, and produce the yellow sulphuret, and lhe arse"

1-1 n • n i i • i • i „ nic unites in.

which we call orpiment : tor the hidrosulphuret of arsenic, the metallic

and the sulphuretted oxide, are two combinations that ap- stale with tna

it xo ■,• ■ ! • . suluhur.

patently do not exist. It we dissolve white arsenic in tho-
roughly saturated hidrosulphuret of potash, and afterward
add an acid, orpiment is precipitated without the least dis-
engagement of gas, without the slightest smell : but on the
one hand the sulphuretted hidrogen is no longer to be found,
and on the other the arsenic in the orpiment is in the metal-
lic state: in this precipitation therefore water is formed. The
pure regulus of arsenic is not soluble in the arsenical hidro-
sulphuret."

If 1 might be permitted to make one observation on this Hi* experi-
passage in Mr. Proust's paper, I would say, that, it seems meuts scycely

to

76 °N ORPIMENT AND REALGAR,

prove the ab- to me> the experiments adduced by this learned chemist are

sence or oxi- , . r

gen. not altogether sufficient to prove the nonexistence of o.vi-

gcn in orpiment : for we may account for the result, whe-
ther we admit the existence of sulphuretted hidrogeu in
this compound, or that of an oxide less oxided than the
white oxide of arsenic. Mr. Proust has said nothing of real-
gar.
Bothsulphu- Both orpiment and realgar, if reduced to powder, and

rets of arsenic • . ■■ » • *■'•*'% ,, i

decomposed on Projected on burning coals, melt, swell up,, and emit sul-
the open fire, phurous acid : but all these phenomena are more obvious
and sublimed with realgar. Heated in close vessels the fusion and tume-
* faction are the same, and they are sublimed without chang-
ing their nature, consequently without giving out any sul-
phurous acid.
Realgar con- Sulphur fused with realgar converts it into orpiment;
g^k " while arsenic fused with orpiment converts it into realgar.

Acids that at- The sulphuric, nitric, nitrous, and oxigenized muriatic
tack them. acid, are, as is well known, the only ones that attack orpi^

ment and realgar.
Sulphuric. Sulphuric acid acts perceptibly with greater power on or-

piment than on realgar. In both cases sulphurous acid
is formed, and likewise arsenious acid ; but more sulphu-
rous acid, and less arsenious, are produced with the orpi-
ment.
ftitrlc, Nitric acid is decomposed by both these substances, even

without the assistance of heat : and orpiment affords with it
more sulphur, and less arsenious acid, than realgar.
Oxigenized With oxigenized muriatic acid, and with the nitro-muri-

nitro-muriatic a*'c' tne same results are obtained as with the nitric.
Alkalis. The alkalis, particularly potash and soda, easily dissolve

both, even cold. Hidroguretted sulphnret. of potash and
arsenite of potash are formed : since on pouring lime-water
into the solution a pretty copious white precipitate is obtain-
ed, which, treated with carbonate of potash, affords a liquor,
that yields, on adding a sufficient quantity of muriatic acid,
and evaporating to a proper point, a great deal of arsenious
acid.

Orpiment con- ^11 these experiments show, that more sulphur is contam-
fcains most sul- . . . . . , , ,. , . , ,

phur, and nei- ed ,n orpiment than in realgar, and some ot them lead us to

ther probably suspect, that no oxigeii is present in either. The following
">J °* wUl

ON ORPIMENT AND REALGAR. 77

*ill serve farther to establish the former fact, and will place

the latter in a stronger light.

It is very certain, that, if arsenic were in the state of ox- These &ulphu«

itle in these compounds, they might easily be formed hy for^}nr^ ar_e

employing arsenious acid and sulphur. But on heating senious acid &

these substances together in a retort, &c, we obtain for a oxiglSgiveu

long time nothing but sulphurous acid: it is not till this gas out.

nearly ceases to come over, that orpiment or realgar is

formed. It may be said indeed, that arsenic is les3 oxided

in these sulphurets, than in arsenious acid. But the exist->

ence of such oxides has never been proved. When arseni- Nointerme-

ous acid is reduced by any method whatever, even by means oxidation.

of bidrogen gas, nothing is ever obtained but arsenious acid

and arsenic, suspend the process at what period of it you

please: and probably, if there were any fixed intermediate

degrees of oxidation, they would be detected by proceeding

in this way. Be this as it may, by combining sulphur with

arsenic in different proportions in close vessels, we obtain at

pleasure orpiment or realgar.

Three parts of sulphur and four of arsenic form orpiment: Extinguishing-

r properties of

one of sulphur and three 'of arsenic form realgar. Realgar thetwosul-

enters into fusion at a very low temperature, and continues L)llurets*
fluid long after the retort is withdrawn from the fire. Orpi-
ment requires a somewhat higher heat to fuse it. Both rise
by sublimation, and adhere to the neck of the retort. The
orpiment is transparent, and of a hyacinth colour, so that
at first it might he taken for a sort of realgar: but native
orpiment itself assumes this colour on being melted ; and
both, that is the native orpiment after its beautiful colour Los
been thus changed, and the artificial, become of a very pure
and lively yellow by pulverization. It is not the same with
the orpiment produced in the humid way. The colour of
this is similar to that of native orpiment that has never been
exposed to heat : and it is in every respect similar to it, whe-
ther it be the prod net of a mixture of arsenious acid and
sulphuretted hidiogen, or of a soluble arsenite, hidrosulphu
.ret, and an acid.

Thus it appears demonstrated, that yellow orpiment in
shining scales, and even endued with a sort of elasticity, is
formed in some fluids; while realgar is produced by arsenic

an<i

78 ■'•

Orpiment and sulphur melted together: and that, since orpiment as-
sometimes may . , , ...... .

be mistaken sumes a hyacinth colour on fusion, similar compounds may

tor realgar. possibly exist in nature, and have been mistaken for realgar.

Neither con- However this may be, it is established beyond a doubt, that

tams oxigen. koth orpjment anj realgar contain no oxigen: they are sul-

Orpimcnt 4 phurets of arsenic more or less sulphuretted. h\ orpiment

parts atonic the arsenic is to the sulphur in the proportion of four to

and S sulphur. - . . . r . 1t. .

^ . 0 three; in realgar, in that of three to one. If more than three

Realgar 3 ar- &

senic and i sul- parts of sulphur be combined with four of arsenic, a yellow
1 r* compound is obtained, the colour of which is not very lively,

But sulphur & ancl approaches more or less to that of sulphur : in like man-

com- neTj if jebS than one part of sulphur be united with three of
nine in various . .

intermediate arsenic, a compound of a browner colour than common real-
proportions, gar is formed : and as sulphur and arsenic are capable of
combining together in a great number of different proportions^
the shades that sulphuret of arsenic may present to us must
be very numerous.

SCIENTIFIC NEWS.
Decomposition of the Alkalies.

Thealkihsde- J[_ jjj? Sl1ororestions of Mr. Davy, in his observations ort
composed. „ , . . , • , , , i •

the agencies of electricity, which we have already given in

this number, see p. 62, have been in some measure verified by

that ingenious and learned gentleman, and produced very

intooxigenand surprising results. Moistened potash and soda, exposed

bk'base"111^ on a Plate of P*alina to the acti°n oi tae galvanic circle, have

been decomposed into oxigen and a base, that in some of its

properties resembles metals. Thus we find oxigen has no

more claim to be considered as the generator of acids, than as

that of alkalis, for it appears to make a part of ammonia

Properties of likewise. The base too is highly inflammable, and forms an

the base of amalgam with mercury: but it is so far from having the

*°l specific gravity of metals, that it is ligher than most fluids.

rihe base of potash has jl specific gravity of 0 6' only: at the

freezing

SCIENTIFIC NEWS. 7?

freezing point it is hard, brittle, and when broken exhibits
facets, as it crystallized, when examined by the microscope :
at 40a it is scarcely distinguishable from a small globule of
quicksilver, at rjO° is quite fluid, mid at 100° evaporates. It
is extremely greedy of oxigen, absorbing it rapidly from the
atmosphere, and resuming the alkaline state. Yet if amalga-
mated with twice its bulk of quicksilver, and applied in the
circuit of a powerful battery to iron, silver, gold, or platina,
these metals are immediately dissolved, and converted into
oxides, while the alkali is regenerated. Glass is dissolved by
it in the same manner as the metals. A globule placed on
a piece of ice burnt with a bright flame and intense heat,
and potash was found in the water from the melted ice. In
this case, as well as when a globule was thrown into water, a
considerable quantity of hidrogen was rapidly evolved. When
a globule was placed on a piece of moist turmeric paper, it
appeared instantly to acquire intense heat, but moved so
rapidly in quest of the moisture, that the paper was no where
burned; but a deep red stain, that marked its course, proved
the regeneration of the alkali. ^

The^base of soda is somewhat heavier than that of potash, Base 0f §ocla.
its specific gravity being 0*7. It remains solid in a tempera-
ture not exceeding 150°, but at 180° it is perfectly fluid.

From a considerable number of experiments potash ap- Proportions of
pears to consist of 85 parts base and 15 oxigen, and soda of oxigen in the
80 parts base and 20 oxigen. It would seem too, that am-
monia contains 20 per cent of oxigen; but this proportion
-was deducted from more complicated calculations, and less
direct experiments.

On examining strontia and barytes, oxigen was educed Strontia an*
from both of them. barytes.

Economical and medicinal uses of Chinese radish oil.

ABOUT fifteen years ago Mr. de Grandi, member of the Chinese radish

Patriotic Society of Milan, introduced and established the produced into
J ? Italy.

cultivation

80 SCIENTIFIC NEWS.

cultivation of a species of radish, the raphanm sinensis. Ths

culture of this plant ha«> been attended with buch success, as

to merit attention.
Yields an ex- The Chinese radish yields a large quantity of oil ; and ex-
th^tobl or Pcrnncnts 'ateb' made at Venice show, that this oil is prefer-
lamps. able to any other kind known, not only for culinary purposes,

■i:u! giving light, but in medicine.

Useful in mc- From the experiments made by Dr. Francis di Oliviero, it

dicine, and is extremely useful in rheumatic and pulmonary affections :

extraor- J l J '

ilinunly well, it is not liable to spoil by keeping like other oils; and it has

been employed with much success in convulsive coughs.

Culture. 'Ihe plant is not injured by the strongest frosts; it is sown

IB September, and in May or June the seed is gathered, whicl*

js very abundant.

Simple process Jo? sailing and smoking meat.

Process for 1° Franconia a method of salting and smoking meat i'e

making excel- employed, that requires only eight and forty hours. The
ifl48houfg/ following is the process. A quantity of saltpetre, equal to
the common salt that would be required for the meat in the
usual way, is dissolved in water. Into this the meat to be
smoked is put, and kept over a slow tire for a few hours, till
all the water is evaporated. It is then hung up in a thick
smoke for four and twenty hours, when it will be found
equal in flavour to the best Hamburg smoked meat, that has
been kept several weeks in salt, as red interiorly, and as firm.

To Correspondents.

I am sorry to inform my correspondent at Whitby, that
his letter was unfortunately lost by the carelessness of the
messenger employed to convey it to mc from the publisher.
If he has retained a copy of it therefore, I would re-:
the favour of him, to transmit it to me.

Dr. Traill's letter will appear in our next number.

A

JOURNAL,

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

FEBRUARY, 1808.

ARTICLE I.

Vn Albhwes: by T. S. Traill, M. D.

To Mr. NICHOLSON.

JL HE following account of a poor family in this town is Albinoe**
transmitted lor insertion in your Journal, if deemed singular
enough to entitle it to a place in that valuable miscellany.
The history was noted down a few days ago in my house from
the words of the mother, who brought with her two of her
children, who in all respects resembles the Albinoes of Cha-
mouni, so well described by de Saussure in his Voyage Dans
les A I pes.

Robert Edmond and his wife Anne are both natives of Their parentf.
Anglesey in North Wales. He has blue eyes and hair almost
black; her eyes are blue, and her hair of a light brown.
Neither of them have remarkably fair skins, They have
been married fourteen years. Their first child, a girl, had
blue eyes and brown hair. The second, a' boy, (now before
me) has the characteristics of an albino: viz. very fair skin,
flaxen hair, and rose-coloured eyes. The third and fourth
children were twins, and both boys; cne of thein has blue
eyes and dark brown hair; the other was an albino. The for-
nier is still alive: the albino lived nine months, though a very

Vol. XIX, Feb. 180S— No. 82. G pun/

82

ON ALBINOES,

The oldest de-
scribed.

The younger.

Approach to It
in a relation.

Supposed want
of the black
mucus in the
eye.

puny child. The fifth child, a girl, had blue eyes and brown
hair. The sixth, and last now here, is a perfect albino.

The oldest of these albinoes is now nine years of age, of a
delicate constitution, slender, but well formed both in person
and in features ; his appetite has always been bad; he fre-
quently com plains of aduli pain in his forehead; his skin is
exceedingly fair; his hair flaxen and soft ; his cheeks have
very little of the rose in them. The iris and pupil of his eyes
are of a bright rose-red colour, reflecting in some situations
an opaline tinge. He cannot endure the strong light of the
sun. When desired to look up, his eyelids are in constant
motion, and he is incapable of iixing the eye steadily on any
object, as is observed in those labouring under some kinds of
slight ophthalmia, but in him it is unaccompanied by tears.
His mother says, that his tears never Ajw in the coldest wea-
ther, but when vexed they are shed abundantly. The white
of the eye is generally bloodshot. He says he sees better by
candle than by daylight; especially at present, when the re-
flection from the snow on the ground is extremely offensive to
him. He goes to school, but generally retires to the darkest
part of it to read his lesson, because this is most agreeable
to his eyes. In my room, which has a northern aspect, he can
only distinguish some of the fetters in the pages of the Edin-
burgh Review; but, if the light is not permitted to fall full
on the book, he is able to read most of them. He holds the
book very near his eye. His disposition is very gentle; he is
not deficient in intellect. His whole appearance is so re-
markable, that some years ago a person attempted to steal
him, and would have succeeded in dragging him away, had
not his cries brought a person to his assistance.

The youngest child is now nine months old ; is a very stout,
lively, noisy, and healthy boy. In other respects he perfectly
resembles his brother.

The mother says, that one of her cousins has a very fair
skin, flaxen hair, and very weak light blue eyes.

Professor Blumehbach of Gottingrn, in a curious memoir
read before the Royal Society of that city, endeavoured to
prove, that the red colour of the eyes of the albinoes of
Chamouni was owing to the want of pigment urn nigrum within

the

ON ALBINOES. 83

the eye. About the same time, Buzzi of Milan had an op«

portunity of dissecting an albino, and proved, that the pig- Proved by dis-

mcnlum nigrum of the choroid coat, and also that portion of

it which lies behind the iris, and is called uvea by anatomists,

were wanting; thus demonstrating what Blumenbach had

supposed. This deficiency was observed before by Blumen- gom"^ !a

bach in some white dogs, owls, and in white rabbits. Buzzi animals too.

discovered, that the layer of the skin called rete mucosum Rete muco-

was also wanting, and to this he with great probability attri- sum a >eut"

butes the peculiar fairness of the skin; the colouring matter

of the negro, and of the hair of animals, being lodged in this

membrane.

Jt is well known, that from the tawny natives of Asia, Albinoes from

Africa, and America, albinoes sometimes spring, who are condnue^hetr

said to be capable of propagating a race like themselves, when race.

they intermarry. Whether this be the case with the albinoes

of Europe is unknown; for, as far as I have been able to European a.U

learn, not one of them was a female. There are on record bi"oes Sfne-

rally males,
eight instances of European albinoes, beside the three now

noticed. Two of these are described by Saussure, four by

Buzzi, one by Helvetius, and one by Maupertuis, all of whom

were males. The parents of the two young men of Chamouni

had female children of the usual appearance. The woman

of Milan had seven sons, three of whom were albinoes.

Mrs. Edmond's girls were all of the usual appearance, but all

her boys were albinoes. Among these eleven cases not one

albino girl has been found. This at least proves, that males

are more subject than females to this singular structure.

From the perpetuation of this variety of the human spe- This variety

ciesinJava, Guinea, and other places, as well as from the becomes here*

. . ditary.

account Mrs. Edmond gives of her cousin, it would seem to

be hereditary.

The causes which produce it arc like those which produce Its cause un-

defects of limbs, or of various viscera, wholly concealed *nown*

from our curiosity. Buzzi relates, that the woman of Milan,

when pregnant with the albinoes, always had an immoderate

longing for milk, which she used to excess; but never felt

that desire while pregnant with her other children; and he

seems to ascribe this longing to some internal heat or disease.

G 2 Mrs,

84 ON ALBINOES.

Mrs. Edmond neither experienced any sensation, which
could lead her to distinguish between each kind of foetus; nor
was her general health sensibly affected in one case more
than in the other. The story of the milk, so much resembles
those invented by our own good ladies to explain tut&i matcmi,
or those singular marks which are sometimes observable on
the bodies of children, that I am not disposed to pay much
attention to it. With regard to the supposed internal disease,
which Buzzi imagines destroyed the rcte mucmum of the albi-
no foetus, it is difficult to conceive any disease of the mother
capable of producing so extensive an effect on one of Mrs.
Edmond's children, while its twin brother was altogether free
from any mark of the existence of such malady. Beside this,
the regular alternation of the albinoes with her other chil-
dren does not favour the notion of their peculiarities arising
Not connected from disease on the system of the mother. De Saussure very
^inous^gion. ProPerb' rejects the idea of this conformation being produced
by the air of mountainous regions. The three albinoes I
have just described were born near the sea, on the extensive
plains of Lancashire, and the birthplace of the parents is the
flat island of Anglesey. Where facts are so few, and the
causes seemingly so remote from human investigation, it is
better to rest satisfied with having observed them, than to
waste time on useless hypothesis.

THOMAS STEWART TRAILL.

Liz v pool, Pec. 9, 1807.

ANNOTATION.

Instance of an Dr. Traill justly remarks the singularity, that of all the
££ l" cascs °f European albinoes on record not one should be a

male. Most of my London readers, however, will be aware,
that a female of this description has been exhibited in the
.metropolis for some years, and is at present at the rooms in
Spiing Gardens. She answers exactly to the full and accu-
rate description of the boy given above. Her hair, I think,
which she suffers to grow very long, has more of a silky
appearance than that of the two male albinoes exhibited

liere

ON ALBINOES. 85

here about twenty years ego, at least to the best of my recol-
lection, and more of the yellow tinge of raw silk. She does
not see better in the dark than other people, but on the con-
trary not so well as most. She is a native of Essex, and [
apprehend between twenty and thirty years old; perfectly
well shaped, about the middle size, and says she has always
been very healthy, which her appearance does not any way
contradict, in her understanding she seems by no means
deficient.

She informs me, that her mother's first child, a girl, is also A second in-
an albiness like herself; that she was the third child; and <uaace*
that the fifth, a boy, is an albino. The two intermediate
children had nothing remarkable. Her mother had never
any peculiar longing, ailment, or fright, she added, during
either of her pregnancies.

Another instance of a female in my own knowledge is the A third,
eldest daughter of a respectable tradesman in Lonoon, about
three and twenty, who has a brother an albino, about ten
years younger than herself. She was the first child of her
parents, the boy the last, and none of the intermediate chil-
dren had any thing peculiar in their appearance.

I am farther informed, that two albinesses, both young, are Two more,
now exhibiting about the country with their brother, who is
an albino. They are said to be natives of Ireland, but I
have not been able to get auy certain information respecting
them.

I likewise remember an albiness, perhaps eight or nine A sixth,
years old, being introduced one evening to the society at
Guy's Hospital about twenty years ago ; and had supposed
it might be the same person as is now to be seen at Spring
Gardens: but she assures me, that neither she nor her sister
had ever been shown at Guy's, or any other place, till she
began to be exhibited in public a few years ago. Thus there
would appear to have been no less than six females of this
description born in the United Kingdom within these thirty
years: and if none have been noticed by writers, it is pro-
bably to be ascribed to the greater care, with which women
endeavour to conceal any thing they would consider as a
personal blemish, or to shun the view of strangers, when

marked

§5 ACCOUNT OF A NEW EUDIOMETER.

marked by any thing singular. In confirmation of this it
may be added, that the young lady I have mentioned conceals
her peculiarity as much as possible by wearing a wig that falls
down over her eyebrows, and a bonnet as large as fashion will
allow.

II.

Description of a new Eudiometer, accompanied ivith Experi-
ments, elucidating its Application. By William Hasle-
dinePepys, Esq. Communicated by Charles Hatchett,
Esq. F.R.S*.

Atmospheric JJ_ jjj£ important part which atmospheric air performs, in
portanceia va- maintaining the principle of life in animals, in combustion
rious natural 0f every description, the acidification, and oxidation of a
processes. great variety of substances, and in numerous other processes

both of nature and art, gives a high degree of interest to
every thing calculated to extend our knowledge of its nature
and properties.
Many other The evidence furnished by modern chemistry, of the ex-

aenform fluids. istence Gf many other aeriform substances, increases this in-
terest, especially when it is considered that, owing to their
possessing some of the most obvious properties of atmosphe-
ric air, as transparency, elasticity, and a power of great ex-
pansion, on being exposed to an increase of temperature,
they were with very few exceptions, till lately, confounded
either with common air, or not even suspected to exist.
Frequently When to these considerations we add the facility, with which

little expected. some products, especially the gaseous, are evolved, in cir-
cumstances under which, in the present state of our know-
ledge, we should hardly look for them ; the power they pos-
sess of decomposing each other, and, by an interchange
and new arrangement of principles, of producing com-
pounds, possessing properties altogether different from those
of the ingredients supposed to be present; and the facili-
ties which every new detection of unsuspected principles

• From the Philosophical Trans, for 1807, Part II, p. 247.

affords,

ACCOUNT OF A NEW EUDIOMETER. 87

affords, toward the diseoveiy of others, and consequently Hence eudio-
the composition, or analysis of bodies before held to be sim- mUchatteii«
pie, it will not appear a matter of surprise, that the subject tion.
of eudioinetry should have obtained a considerable degree
of attention from modern philosophers.

This would be an improper place to enumerate all that Whathasbeea
has been done, or proposed, by different men of eminence, '!on.e on the
towards the production of something like a perfect system
on this important subject; yet some allusion to their labours
appears to be indispensible, and will be the means of pre-
venting some circumlocution in our farther progress.

Hales* appears to be the tirst who observed absorption Hales.
to take place in common air, on mixing it with air obtained
from a mixture of Walton pyrites and spirit of nitre; and
that in this process from being clear they became " a red-
dish turbid fume."

Dr. Priestley, as he informs us in his Observations on dif- Priestley.
Jerent kinds of 'Airt, was much struck With this experiment,
but never expected to have the satisfaction of seeing this re-
markable appearance, supposing it to be peculiar to the
Walton pyrites, till encouraged by a suggestion of Mr. Ca-
vendish, that probably the red appearance or the mixture
depended upon the spirit of nitre only, he tried solutions of
the different metals in that acid, and, catching the air which
was generated, obtained what he wished. To the air thus
produced he gave the name of nitrous air; and, from its
possessing the properties of absorbing that portion of atmos-
pheric air which he calls dephlogisticuted, first proposed its
being used as a test for ascertaining tiie purity of air. Kis The first eudi#-
znethod of proceeding was ingenious and simple; known meter«
quantities of the air to be tried, and of nitrous gas, being
mixed, were admitted, after the diminution of volume occa-
sioned by their union, into a graduated tube, which he de-
nominated a eudiometer.

It was with the test of nitrous gas, that Mr. Cavendish J Cavendish's
made his masterly analysis of the air at Kensington and common°air.
'London ; and by many laborious processes and comparative

* Statical Essays, Vol. I, p. 224 5 Vol II, p. 280.
J Phil. Trans, for 1783, f Phil. Trans, for 1772, p. 210.

trials ►

§8 ACCOUNT OF A NEW EUDIOMETER. „

trials obtained results, the accuracy of which has been more
distinctly perceived, the more the science of chemistry has
advanced.

The slow combustion of phosphorus, which unites with
Phosphorut the oxigen to form an acid, and the decomposition of the
and s 1 .huret flyij sulpnuret of potash, are certain methods of separating

oi potash cm- ... • . , ,

ployed. combmatioua consisting ot oxigen and azote: but the de-

composition is effected so slowly, by the action of these sub-
stances, that it became a desirable object, to discover some
means for accelerating the process. This was supposed to
have been effected by Gnyton, who proposed heating the
Guyton. sulphuret of potash ; in doing this, sulphuretted hidrogen gas

however is frequently evolved, which, mixing with the residual
gas, increases its quantity, and renders the result fallacious.
Davy, The green sulphate of iron impregnated with nitrous gas,

§, iphate of first discovered by Dr. Priestley, and recently used by Mr.
iron impregna Davy for eudiometrical purposes, from its possessing the
gas. property of absorbing oxigen gas from the atmosphere, is

much to be preferred to the method with nitrous gas, as the
green sulphate of iron does not combine with the other
gassea, with which the nitrous gas is commonly found to be
contaminated, and more certain results are obtained.
A correct and Having had occasion to repeat many of the experiments
com mo bus Gf others, and to make some new ones, I soon found what
wanting. * every o ie, who has been eugaged on the same subject, must
have experienced; that an apparatus more commodious than
has yet been proposed, and at the same time capable of
giving correct results, with the greatest minuteness, was still
a desideratum in eudiometry. To detail the various ideas,
that presented themselves on the subject, would be an un-
necessary encroachment on the time of this Society : but as
I at last succeeded in contriving an instrument, possessing
the above properties in a very eminent degree, I flatter my-
self I shall not be thought intrusive, in offering a description
of it.
Description of ^n*s aPParatus» which is of easy construction, and cx-
med tremely portable, consists of a glass measure M, pi. Ill, fig.
by theau.hor. ^ gracluated into hundred parts; a small gum elastic bottle
B, tig, 4, capable of containing about twice the quantity of
the measure, and furnished with a perforated glass stopper,

S,

NiAohmts POu-- Jmnwl. KlSLPlULp,

( 4mr defamsnt/,

tMy^oy

ffyj.

Kg.\

1 2 3 4 3 £ J*

.^iijiiii

Fi#.4.

Hff.5.

ACCOUNT OF A NEW EUDIOMETER. 89

$, which is well secured in the neck of it, by means of
waxed thread wound tight round it : and a "lass tube, T,
fig. 3, also graduated, but into tenths of the former divisions,
or into thousandth parts of the measure.

The glass stopper, made fast in the neck of the gum elas-
tic bottle, as aboVe mentioned, has its exterior end ground
with emery, exactly to tit the mouth of the measure. To
the lower end of the graduated tube T is cemented a small
steel cock, which is secured into the neck of a very small
gum elastic bottle, fig. 2, by means of waxed thread. The
other end of the tube is conical, so as to present a very
small orifice.

Beside this, the apparatus is furnished with a kind of
movable cistern C, in which the tube can be slid easily up
and clown, and yet in such a manner, that the water or other
liquid in the cistern may not pass. This is easily accom-
plished by means of a cork fitted into its mouth, with a
perforation through its axis to receive the tube. The cis-
tern, when in use, is to be filled with water, or mercury, as
the experiment may require, and becomes a secondary cis-
tern for the measure, as will be more clearly understood, by
the following description of the method of performing ex-
periments with this instrument.

The measure is filled with the air, or gas, over mercury in Manner of
the usual manner; and the elastic bottle is charged with the usillS **•
solution, intended to be employed as the reagent : the orifice
of the stopper is then inserted into the mouth of the mea-
sure, in the mercury, and pressed home to its place.

The bottle and measure, being thus united, are to be
firmly held at the joint. Upon pressing the former, a por-
tion of the fluid is injected into the latter, and the gas suf-
fers a degree of compression, by which the action of the af-
finitv, between it and the fluid, is accelerated. On taking

o

off the pressure, the bottle, by its elasticity, endeavours to
obtain its original form, and receives back the fluid. This
process should be continued as long as any absorption is ob-
served to take place. When absorption ceases, the bottle is
to be separated from the measure under mercury, and the
quicksilver which remains in the measure being brought to

the

gO ACCOUNT OF A NEW EUDIOMETER.

the level of that in the cistern, the quantity of absorption is

then to be determined, which is done as follows :

Method of as- Suppose atmospheric air has been the subject of the expe-
certaining the j ,, , • «»«.',»

absorption. nment, and consequently a large residuum hit: rirst note

the hundredth parts: and then, to obtain a knowledge of
the fractional parts, remove the measure into the small cis-
tern, in which the graduated tube tilled with mercury is
placed; slide the tube above the surface of the fluid in the
measure, and, opening the stop-cock, sutler the mercury to
descend, till it has drawn the fluid in the measure to a regu-
lar division ; then stop the rock, and register the hundredth
parts on the measure, and the thousandth parts on the gradua-
ted tube; the united quantities give the sum of the residual
gas. Observe well in registering the thousandth parts, that the
fluids are exactly on a level, on the outside and the inside of
the measure; this may be easily effected, by pouring out a
portion of the liquid o*' the small cistern, or adding thereto.
When the re If instead of atmospheric air, a gfts is tried, which so far as
small™ 1S ^ '* *s "^contaminated can be nearly wholly absorbed by the
reagents employed, the process becomes exceedingly simple;
for if the residuum is under a hundredth part of the measure,
it may be transferred completely into the graduated tube,
and its quantity at once ascertained.

The stopper S would have injected the fluid with greater
velocity had it been straight ; but it would not then have been
so convenient in the analysis of compound gasses, where both
mercury and hot solutions are occasionally employed; as the
mercury would have so compressed the fluid in the bottle, in
introducing it under that metal, as to have thrown out a por-
tion of its contents, and also have robbed the hot solutions of
the temperature, which was necessary to their perfect action.
Mode of re- As to the size of the measure M, 1 have generally preferred

ducing the ^ cu|^c ^^ divided into hundredth parts. This is easily
measure to a i . ;

proper size, effected by taking a stout glass tube about half an inch cali-
bre, sealing one end, then weighing 3422 grains of mercury,
equal to 252 grains of distilled water at temperature 50°
Fahrenheit. This is introduced into the tube; the extra
length is cut off with a sharp-edged file, care being taken to
leave a sufficient portion to grind the perforated stopper S

into its mouth.

The

Advantage of
the bent tube

ACCOUNT OF A NEW EUDIOMETER. 0/1

The divisions are obtained by a small measure, made from and graduating
a glass tube sealed at the end, and cut off exactly to the hun-
dredth part of a cubic inch, equal to 34'2 grains of mercury,
which, being ground flat, is stopped by a piece of plate-glass,
and the divisions marked by the diamond, upon the introduc-
tion of each hundredth part of mercury into the measure M.

The tube T is divided into tenths of the measure M, or Mode of gra.
thousandth parts of a cubic inch. This is done by measur- du£thlS ^
ing one hundredth part of a cubic inch into the tube, and di-
viding it into ten parts,markingthe divisions with fluoric acid,
or black enamel.

To prove the accuracy of the instrument, I shall proceed to
relate a few experiments made with it.

The elastic bottle being filled with the solution of sulphate Experiment*

of iron impregnated with nitrous gas, and the measure with t0 Prove »»

, ... -.ill Al • • ■• accuracv.

atmospheric air, they were united, and by gentle injection

tVW were absorbed.

If the experiment is made hastily, the impregnated solu-
tion loses a portion of its nitrous gas, which must be again
absorbed by a solution of green sulphate of iron.

For ascertaining the purity of nitrous gas, the bottle may
be charged with the solution of green sulphate or muriate of
iron.

For carbonic acid gas, with lime or barytic water.
For oxigen gas*, with the solution of green sulphate of
iron impregnated with nitrous gas.

For sulphuretted hidrogen gas, a solution of nitrate of sil-
ver was put into the elastic bottle, and sulphuretted hidro-
gen gasf into the graduated measure. Upon the first injec-
tion, the solution took a black flocculent appearance, and a
considerable portion of the gas was absorbed. After re-
peating the process as before mentioned, the residuum was

TTSTTTo*

The instrument may be likewise generally applied to the Mixed gasses
analysis of mixed gasses. may be ana*

I have been able completely to separate the carbonic acid
gas from the sulphuretted hidrogen, by a solution of the ni-

* Obtained from oximuriate of potash by heat.

f Obtained from sulphuret of potash by diluted muriatic acid, and col-
lected and preserved with the greatest care.

trate

92

ACCOUNT OF A NEW EUDIOMETER.

trnte of silver, or of mercury employed hot. The carbonic
acid gas is expanded in this process, but on standing over
mercury it returns to its original volume. The sulphuretted
hidrogen, in this instance, is taken up by the metallic nitrate.
Carbonic acid It should be here observed, that theacetite of lead must not

pose^accSte of be ll8e<*» as the carl:)onic Hci<t gas» even at a high tempera-,
lead. ' ture, decomposes it, forming carbonate of lead.

Whythesolu- The propriety of using the solutions hot will be seen,
used hot. G wnen we ^collect, that the carbonic acid gas is soluble in the
water of solution at the common temperature of all these
compounds.
Nitrous gas and Nitrous gas, and carbonic acid gas, may be separated by
carbonic acid means of the hot solution of the green sulphate of iron. To
effect this, heat a solution on a glass capsule over a spirit lamp
until ebullition. Having filled the measure with the com-
pound gas, charge the elastic bottle with the hot solution,
and unite them. The nitrous gas in two or thee injections
will be absorbed, changing the colour of the solution, while
the carbonic acid gas will be a little rarefied, but no absorp-
tion of it will take place.
Ga*ses ab- Previous to these experiments on the compound gasses, I

sorbed by alco- jlad tried geveral Qn tne carbonic acid, sulphuretted hidro-

faoj, . . ,

gen, and nitrous gasses in their unmixed states. One hun-
dred parts of pure alcohol at the common temperature will
absorb 70 parts in volume of carbonic acid, and the same
quantity of sulphuretted hidrogen. Alcohol impregnated
with the latter precipitates the solutions of the nitrates of

by nitric acid, lead, silver, and mercury, of a dark brown colour. Nitric
acid of the specific gravity 1*4, and also of T25, absorbs
carbonic acid gas, without any apparent change in the nitric
acid. Sulphuretted hidrogen gas is also absorbed by nitric
acid, which occasions a slight milky cloud or precipitate
therein.

and by nitrates. The solutions of nitrates of barytes, strontian, and lime,
absorb carbonic acid gas equal to half their volume, without
any apparent alteration.

Solutions of nitrates of barytes, strontian, and lime, also
absorb sulphuretted hidrogen gas, equal to T%- of their vo-
lume, with a slight change of eoiour; the solutions thus
impregnated precipitate solutions of nitrate of mercury and

•f

ACCOUNT OF A tf£W EUDIOMETER. £3

•f silver, and acetite of lead, of a dark. brown colour, and
would be useful as chemical reagents.

Carbonic acid gas, as 1 have before stated, decomposes so-
lutions of the acetite of lead, hot or cold, forming a precipi-
tate of carbonate of lead.

Carbonic acid gas is absorbed by the solution of the green Carbonic acid
sulphate of iron, under the temperature of 100° Fahren- Sa= absorbed
■ • i i • it • f i /> i on'y hy the

heit: but this is only the action or the water or solution. water in solu_

If the temperature be near boiling, or above 180° Fahren- tion of sul-

heit, the solution increases the volume of the gas without

the slightest absorption ; after carbonic acid gas has in this

way been treated with the hot solutions, it is still soluble in

water at the common temperature, or in aqueous solutions

of lime, or alkali.

Nitrous gas is absorbed by solution of sulphuret of pot- Nitrous gaS.
ash, with a separation or formation of sulphur. Upon inject-
ing the solution the sides of the measure take a milky ap-
pearance, which on the second injection is washed down, in-
soluble in the liquor. About 80 parts from 100 of gas are
absorbed.

Nitrous gas is also absorbed by nitrate of copper in solu-
tion, without any peculiar alteration.

In these experiments, great care must be taken not to in- Forceps used

crease the temperature of the gas by the hand. To prevent to Prevent to-

i-r c n-i ito -.•! crease ©f tem-

tlus 1 use a pair or small circular-mouthed forceps, lined pw-ature from

with cloth, which firmly grasp the measure, fig. 5 ; and if the hand,
the experiments should in any way be delayed, a correspond-
ing manometer will always be. sufficient to correct the errour
occasioned by change of atmospheric temperature and pres-
sure.

To ascertain the quantity of carbonic acid gas, contained Examination
in oxigen gas (of a known purity,) after combustion, or de- of oxiSen *°r
composition of carbonaceous substances, lime water will be after Combu*.
found sufficient. tion,

If it is required to know the purity of the oxigen gas, af- an(j for otjier
ter the carbonic acid gas has been absorbed, the best method, gasse*.
and the least liable to errour, is to withdraw the residual oxi-
gen gas, by means of the small graduated tube before de-
scribed.

To do this, remove the measure into the small cistern of

mercury :

C)4 ACCOUNT OF A NEW EUDIOMETER.

mercury; press the quicksilver out of the small bottle by
the fingers and thumb, and let the tube rise a sufficient
height within th<- measure, that the bottle extending itself
shall withdraw ihe whole of the gas from the measure, tak-
ing care that the cock be stopped as soon as '.t has completed
it, and also to prevent the solution from entering the tube.

If the i f the tube is small, it may then be drawn

down into the mercury, without the possibility of any portion

of the g. 'bile the measure is dried or cleaned,

or a fresh one tilled with mercury supplied to receive k.

Convenience ^is WH* °* transferring will be found very advantageous*

of this mode of particularly in the separation of gasses liable to be absorbed

transferring under certain temperatures ; and also where a new series of

gasses. r

reagents is to be employed, as from the depositions of for-
mer solutions on the glass measure a source of .considerable
-errour would arise.

Farther in- ^ ne residual oxigen gas being thus transferred into a clean

structions for <]ry measure, the processes before described for examining
using the ap- . , , , , , „ ,

paratus. oxigen gas may be then used ; or the quantity ot carbonic

acid gas (for examination) being found by lime water, another
measure of the gas may be tried, iirst with the green sul-
phate of iron impregnated with nitrous gas, and then with
the green sulphate in solution only : these will take up both
the carbonic acid gas, and the oxigen gas, leaving only such
residual gas as the oxigen might have originally contained.

Transferring is not here necessary, as the two solutions
may be used one after the other, taking care to use the so-
lution of green sulphate last.

Where it is not requisite to transfer the gas into a dried or
clean measure, previous to the use of another solution, as in
the instance I have just mentioned, a quantity of the first
solution may be withdrawn, by simply filling the elastic bot-
tle with mercury, then joining it to the measure, and by in-
clining the measure, the mercury by its gravity will displace
the former solution.

If at any time the gas should get drawn into the elastic
bottle, it may be very easily returned into the measure, by
inclining sometimes the bottle, and sometimes the measure.
The only errour that could arise from this is, an increase of
temperature in the gas, which may be rectified, by plunging

the

MODE OF MANAGING STRAWBERRIES. Q$

the whole apparatus into mercury, or water, of the standard
temperature.

The advantages of this construction of the eudiometer Advantages of
.,.,-. i i -ii T--x r« this euuiomt-

will be readily perceived by all those, who are in the habit ot ter>

ittftking chemical experiments. The portion of gas to be

examined is completely under command ; it may be agitated

without the least fear of the intrusion of any atmospheric air,

and the process thereby very materially shortened. The

gum elastic is a substance so little acted upon by chemical i

agents, that a great variety may be employed; and above

all, we can very conveniently use hot solutions, which will

be found an important auxiliary in the examination of some

compound gasses.

Simple as this instrument may appear, it is calculated to
extend our knowledge of the different kinds of air, by the
precision and accuracy which it enables us to obtain, and
which solely constitute the value of every experiment.
A degree of confidence is inspired from knowing, that we
can depend upon our results; and hence much valuable
time, which would have been wasted in uncertain, if not
useless investigations, may be directly applied to the ad-
vancement of science.

III.

On the Revival of an Obsolete Mode of managing Straw-
berries. By the Right Hon. Sir Joseph Banks, Bart.
K.B. P.R.S.Sfc* '

JL HE custom of laying straw under strawberry plants, straw formerly
when their fruit begins to swell, is probably very old in this laili under
country: the name of the fruit bears testimony in favour of piants iu'thi*
this conjecture, for the plant has no relation to straw in any country.
other way, and no other European language applies the idea Hence the
of straw in any shape to the name of the berry, or to the narae*
plant that bears it.

When Sir Joseph Banks came to Spring Grove, in 1779» Practised with*

* From the Transactions of the Horticultural Society, Vol. I, Part I, p. 54.

he

<)6 MODE OF MANAGING STRAWBERRIES.

in these GO he found this practice in the garden: John Smith, the gar-
years., dener, well known among- his brethren as a man of more
than ordinary abilities in the profession, had used it there
many years; he learned it soon after lie came to London
from Scotland ; probably at the Neat Houses, where he first
worked among the maiket gardeners, if is therefore clearly
an old practice, though now almost obsolete.
Attended with ^ts UkS(" U1 preserving a crop is very extensive: it shades
various advan- the roots from the sun ; prevents the waste of moisture by
tages. evaporation, and consequently, in dry times, when watering
is necessary, makes a less quantity of water suffice than
would be used if the sun could act immediately on the sur-
face of the mould ; besides, it keeps the leaning fruit from
resting on the earth, and gives the whole an air of neatness
as well as an effect of real cleanliness, which should never
be wanting in a gentleman's garden.
Expense of the The strawberry beds in that garden at Spring Grove,
practice which has been measured for the purpose of ascertaining
the expense incurred by this method of management, are
about 75 feet long, and five feet wide, each containing three
rows of plants, and of course requiring four rows of straw to
be laid under them. The whole consists of 600 feet of
beds, or 1800 feet of strawberry plants, of different sorts, in
rows. The strawing of these beds consumed this year, 1 806,
the long straw of 26 trusses, for the short straw being as good
for litter as the long straw, but less applicable to this use, is
taken out ; if we allow then, on the original 26 trusses, six
ajnere trifle. f°r tne short straw taken out and applied to other uses, 20
trusses will remain, which cost this year 10c/. a truss, or l6jr.
8c?. being one penny for every nine feet of strawberries in
rows.
The straw From this original expenditure the value of the manure
makes manure: made by the straw when taken from the beds must be de-
ducted, as the whole of it goes undiminished to the dung-
hill as soon as tie crop is over. The cost of this practice
therefore cannot be considered as heavy ; in the present year
not a single shower fell at Spring Grove, from the time the
straw was laid down till the crop of scarlets was nearly
smd much la- finished, at the end of June. The expense of strawing was
kour and water therefore many times repaid by the saving made in the la-
bour

ON RAISING NEW VARIETIES OF THE POTATO. QJ

bonr of watering, and the profit of this saving was immedi- saved by it in
ately brought to account in increase of other crops, by the ry seasons:
use of water spared from the strawberries ; and besides, the
berries themselves were, under this management, as fair and
nearly as large as in ordinary years, but the general com-
pliant of the gardeners this year was, that the scarlets did
not reach half their natural size, and of course required
twice as many to (ill a pottle as would do it in a good year.

In wet years the straw is of less importance in this point In moderately

of view, but in years moderately wet, the use of strawing wet years ren"

J . . ders watering

sometimes makes watering- wholly unnecessary, when gar- unnecessary.

doners who do not straw are under the necessity of resorting

to it ; and we all know if Watering is once begun, it cannot

be left off till rain enough has fallen to give the ground a

thorough soaking.

Even in wet years the straw does considerable service, And in wet

heavy rains never fail to dash up abundance of mould, and J^rable ser-"

fix it upon the berries, this is entirely prevented, as well as vice.

the dirtiness of those berries that lean down upon the earth,

so that the whole crop is kept pure and clean : no earthy

taste will be observed in eating the fruit that has been

strawed, and the cream which is sometimes soiled when

mixed with strawberries, by the dirt that adheres to them,

especially in the early part of the season, will retain to the

last drop that unsullied red avid white, which give almost

as much satisfaction to the eye while we are eating it, as

the taste of that most excellent mixture does to the palate.

IV.

On raising new and early Varieties of the Potato (Solanum
Tuberosum). By Thomas Andrew Knight, Esq,
F. R. S. 8fc*

.r

JL HE potato contributes to afford food to1 so large a por-
tion of the inhabitants of tins country, that every improve-
ment in its culture becomes an object of national impor-

* From the Trans, of the Horticultural Society, toI I,-p. I, p. 57.

Vol. XIX. Feb. 1808. H tance;

sums.

QS ON RAISING WF.TT VARIETIES OF THE POTATO.

tance; and thence 1 am induced to hope, that the following
communication may not be unacceptable to the Horticultu-s
ral Society.

tarty notators Every Person, who has cultivated early varieties of this
about bios- p]an^ must have observed, that they never afford seeds, nor
rven blossoms; and that the only method of propagating
them is by dividing their tuberous roots: and experience

Degenerate .has sufficiently proved, that every variety, when it lias been

from continued j0 propagated, loses gradually some of those good quali*
propagation by . ° r . r ■ ? *' . P . l

roots/ ties, winch it possessed m the earlier stages ot its existence.

Dr. Hunter, in his Georgical Essays, I think has limited
Varieties con- the duration of a variety, in a state of perfection, to about
fLaio^ahout fourteen years i and probably, taking varieties in the aggre-
14 years. gate, and as the plant is generally cultivated, he is nearly

accurate. A good new variety of an early potato is there-
fore considered a valuable acquisition by the person, who
has the good fortune to have raised it; and as an early va-
riety, according to any mode of culture at present practised,
can only be obtained by accident from seeds of late kinds,
one is pot very frequently produced: but by the method I
have to communicate, seeds are readily obtained from the
earliest and best varieties ; and the seeds of these, in sucn
cessive generations, may, not improbably, ultimately afford
mueh earlier and better varieties, than have yet existed.
Early potatoes I suspected the cause of the constant failure of the early

tail to seed, p0tato to produce seeds, to be the preternatu rally earlv for-?
irom soon r r r . *

forming tubers mation of the tuberous root ; which draws off, for its sup-
port, that portion of the sap, which, in other plants of the
same species, affords nutriment to the blossoms and seeds:
and experiment soon satisfied me, that my conjectures were
perfectly well founded.

I took several methods of placing the plants to grow, iq
such a situation, as enabled me readily to prevent the for-
mation of tuberous roots; but the following appearing the
best, it is unnecessary to trouble the Society with an account
of any other.
Method of pie- Having fixed strong stakes in the ground, I raised the
venting this, mouhj in a heap round the bases of them; aiid in contact
with the stakes, on their south sides, I planted the potatoes
from which I wished to obtain seeds. When the young

plants

CHILDREN BORN BLIND RESTORED TO SIGHT. gg

plants were about four inches hi <>-h, they were secured to the
stakes with shreds and nails, and the mould was then
washed away, by a strong- current of water, from the bases
of their stems, so that the fibrous roots only of the plants
entered into the soil. The librous roots of this plant are The proper
perfectly distinct orija'ns from the runners, which give exis- ~uot <h->tinct
teuce, and subsequently convey nutriment, to the tuberous ners.
roots; and as the runners spring from the stems only of the
plants, which are, in the mode of culture I have described,
placed wholly out of the soil, the formation of tuberous
roots is easily prevented; and whenever this is done, numer-
ous blossoms will soon appear, and almost every blossom
will afford fruit and seeds. It appears not improbable, that Moderately
by introducing the farina of the small, and very early varie- perh/Tob165
ties into the blossoms of those of larger size, and somewhat tainableby
later habits, moderately early varieties, adapted to field cul- mixture-
ture, and winter use, might be obtained ; and the value of
these to the farmer in the colder parts of the kingdom,
whose crop of potatoes is succeeded by one of wheat,
would be very great. I have not yet made any experiment
of this kind; but I am prepared to do it in the present
spring.

V.

An Account of two Children bom with Cataracts in their
Eyes, to show that their Sight teas obscured in very different
Degrees; with Experiments to determine the proportional
Knowledge of Objects acquired by them immediately after
the Cataracts icere removed. By Everard Home, Esq.
F.R.S*.

R. Cheselden's observations on this subject, recorded Cheselden's
in the Phil. Trans, for the year 1728, pointed out two mate- observatioils»
rial facts ; that vision alone gives no idea of the figure of ob-
jects. or their distance from the eye, since a very intelligent

* Phil. Trans, for 1806, Part I, p. 83.

H 2 bov,

100 CHILDREN BORN BUND RESTORED TO SIGHT-

boy, 13 years of age, upon recovering his sight was unable to
distinguish the outline of any thing placed before him, and

thought that every object touched his eye.
Ware's in op- Mr. Ware's cases, which have also a place in the Phil,
sition to thorn. Trans. foj, lg0^ ^ ^ (<oull);irC(l Wlth that 0f ^ Chesel-

den, appear to lead to a different conclusion. The fallowing
observations are laid before the Society with a view to explain
this circumstance.

Bey bom Case 1. William Stiff, twelve years of age, was admitted

into St. George's Hospital under my care, on the 17th of
July, 1S06, with cataracts in his eyes, which, according to
the account of his mother, existed at the time of birth.
From earliest infancy he never stretched out his hand to catch
at any thing, nor were his eyes directed to objects placed be-
fore him, but rolled about in a very unusual manner, although
in other respects he was a lively child. The eyes were not
examined till he was six months old, and at that time the
cataracts were as distinct as when he was received into the
hospital.

Distinguished Previous to an operation being performed, the following

light, & could circumstances were ascertained respecting his vision. He
discern the sua ,a ■»;... •,,-,,. , , , , ,• , /> ,

eracandk*. could distinguish light from darkness, and the light of the

sun from that of a tire or candle: he said it was redder, and
more pleasant to look at, but lightning made a still stronger
impression on his eyes. All these different lights he called
red. The sun appeared to him the size of his hat. The
candle flame was larger than his finger, and smaller than his
arm. AY hen he looked at the sun he said it appeared to
touch his eyev When a lighted candle was placed before
him both his eyes were directed towards it, and moved toge-
ther. When it was at any nearer distance than 1-2 inches,
he said it touched his eyes. When moved further off he
said it did not touch them; and at 22 inches it became in-
viable.
One of the ca- On the 21st of July the operation of extracting the crys-
Jarac* , c.x"7 tailine lens was performed on the left eye. The capsule of
years of age. the lens was so very strong as to require some force to pene-
trate it. When wounded, the contents, which were fluid,
rushed out with gr< at violence. Light became very distress-
ing to his eye, and gave him pain. After allowing the eye-

lidl

CHILDREN BORN BLIND RESTORED TO SIGHT. 101

l'ds to remain dosed for a few minutes, and then opening
them, the pupil appeared elear, but be conld not bear ex-
posure to light. On 1117 asking him what he had seen, he J ®\j ° * e
said, " your head, which seemed to touch my eye:" but he
could not tell its shape. He went to bed, and took an opi-
ate draught: the pain in his eye lusted about an hour, after
which he fell asleep. The whole of that day the light was
distressing to his eye, so that he Could not bear the least ex-
posure to it.

On the 22d the eye-lids were opened to examine the eye.
The light was less offensive. He said he saw my hfad,
which touched his eye. There was so much inflammation
on the eye-ball, that a leech was applied to the temple, and
the common means for removing inflammation were used.

On the 23d the eye was less inflamed, and he could bear
a weak light. The pupil was of an irregular figure, and
the wounded cornea had not united frith a smooth surface.
lie said he coald see several gentlemen round him, but
could not describe their figure. My face, while I was look-
ing at his eye, he said was round and red.

On the 25th the inflammation had subsided, but on the
27th returned, and continued notwithstanding different
means were employed for its removal, till, the 1st of August,
when it was almost entirely gone. On the 4th the eye was
apparently so well, that an attempt was made in the pre-
sence of Mr. Cavendish and Dr. Wollaston to ascertain its
powers of vision ; but it was so weak, that it became ne-
cessary to shade the glare of light by hanging a white cloth
before the window. The least exertion fatigued the eye,
and the cicatrix on the cornea, to which the iris had become
attached, drew it down so as considerably to diminish the
pupil. From these circumstances nothing could be satis-
factorily made out respecting the hoy's vision. On the 11th
a second attempt was made in the presence of Mr. Caven-
dish, but the pupil continued so contracted and irregular,
and the eye so imperfect in its powers, that it became neces-
sary a second time to postpone any experiments.

On the 16th of September the ri^ht eye was couched. The other ey«
This operation was preferred after what had happened to the coucie<*
other eye, in the hope that there would not be the same de-
gree

IOC CHILDREN BORN BLIND RESTORED TO SIGHT.

gree of inflammation, and as the former cataract was fluid,

there was every reason to believe that couching would in this

instance be most efficacious.

Effectsof this The operation gave pain, and the light was so distressing

operation. ^Q j^g e^e> tj)at tjie yK^b were closed as soon as it was over,

and he was put to bed. The consequent inflammation was
not severe, but as soon as the fluid cataract, which had been
diffused through the aqueous humour, was absorbed, the
capsule of the lens was found to be opaque, and the sight
consequently imperfect. The eyes were not examined with
respect to their vision till the 13th of October, during which
period the boy remained quiet in the hospital. On that day
the upper part of the pupil of the left eye had in some mea-
sure recovered its natural state, and had become transparent,
but the cicatrix in the cornea was more extensively opaque
than before. The light now was not distressing to either
eye, and when strong, he could readily discern a white, red,
or yellow colour, particularly when bright and shining.
The sun and other objects did not now seem to touch his
eyes as before, they appeared to be at a short distance
from him. The eye, which had been couched, had the most
distinct vision of the two, but in both it was imperfect.
The distance at which he saw best was five inches.

When the object was of a bright colour, and illuminated
by a strong light, he could make out that it was fiat and
broad ; and when one corner of a square substance was
pointed out to him, he saw it, and could find out the other,
which was at the end of the same side, but could not do this
under less favourable circumstances. When the four cor-
ners of a white card were pointed out, and he had examined
them, he seemed to know them, but when the opposite sur-
face of the same card, which was yellow, was placed before
him, he could noeteli whether it had corners or not, so that
he had not acquired any correct knowledge of them, since
he eould not apply it. to the next coloured surface, whose
form was exactly the same, with that, trie outline of which
thee^e had just been taught to trace. »

rhoy C.AflE (1. John Salter, seven years of age, was admitted

bom blind. iniQ st Gem,,e's n0Spital on the 1st of October, 1 S06', un-
der

CHILDREN BORN BLIND RESTORED TO SIGHT. 103

der Wcu re, with cataracts in both eyes, which according to
llte&iccotH ts of his relations had existed from his birth.

After he was received into the hospital, the following cir- Distinguished;
cumstanees were ascertained respecting his vision. The pu- u»ht & colours
pils contracted considerably when a lighted candle was
placet! before him, and dilated as socn as it was withdrawn.
He was capable of distinguishing colours with tolerable ac-
curacy, particularly the more bright aud vivid ones.

On the fith of October the left eye was couched. This One eye
operation was preferred to extraction, from a belief, that the "^ ol(Ja
cataracts were not solid, and as the injury done to the- cap-
sule by the operation would be less, there was not the same
cha ace or' inflammation, the disposition for which had been
so strong in the former case. As the -eye was not irritable,
and was likely to be but little disturbed by this operation,
every thing was previously got ready for ascertaining his
knowledge of objects, as soon as the operation was over,
should the circumstances prove favourable. The operation Effects of the
was attended with success, and gave very little pain. The operation.
eye was allowed ten minutes to recover itself: a round piece
of card of a yellow colour, one inch in diameter, was then
placed about six inches from it. He said immediately, that
it w * yeilow, and on being asked its shape said, ■'.« Let me
touch it, and 1 will tell you*" Being told that he must
not touch it, after looking for some time, he said it was
round. A square blue card, nearly the same size, beiug put
before him, he said it was blue and round. A triangular
jjieee he also called round* The different colours of the
objects placed before him he instantly decided on with
great correctness, but had no idea of their form. He moved
his eye to different distances, and seemed to see best at G or
7 inches. His focal distance has been since ascertained to
be 7 inches. He was asked whether the object seemed to
touch his eye, he said " No ;" but when desired to say at
what distance it was, he could not tell. These experiments
were made in the theatre of the hospital, in which the opera-
tion was performed* before the surgeons and all the students.
He was highly delighted with the pleasure of seeing, and
said it was " so pretty," even when no object was before
Jiim, only the light upon his eye. The eye was covered,

and

104 CHILDREN BORN BUND RESTORED TO SIGHT.

Sense of vi>ion and he was put to bed, and told to keep himself quiet, but
af tfr the oper- , ■ . r ! '

ation. upon the house-surgeon going to Intn half an hour after-

wards, his eye was found uncovered, and he was looking at
his bed curtains, which were close drawn. The bandage
was replaced, but so delighted was the boy with seeing-, that
he again immediately removed it. This circumstance dis-
tressed the house-surgeon, who had been directed to pre-
vent him from looking at any thing till the next day, when
the experiment was to be repeated. Finding that he could
not enforce bis instructions, he thought it most advisable to
repeat the experiment about two hours after the operation.
At first the boy called the different cards round ; but upon
being shown a square, and asked if he could rind any cor-
ners to it, he was very desirous of touching it. This being
refused, he examined it for some time, and said at last, that
he had found a corner, and then readily counted the four
corners of the square; and afterwards when a triangle was
shown him, he counted the corners in the same way; but in
doing so his eye went along the edge from corner to corner,
naming them as he went along.

Next day, when I saw him, he told me he had seen " the
soldiers with their fifes and pretty things." The guards in
the morning had inarched past the hospital with their band;
on hearing the music he had got out of bed, and gone to the
window to look at them. Seeing the bright barrels of the
musquets, he must in his mind have connected them with
the sounds which he heard, and mistaken them for musical
instruments. On examining the eye 24 hours after the ope-
ration, the pupil was found to be clear. A pair of scissors
was shown him, and he said it was a knife. On being told
he was wrong, he could not make them out; but the mo-
ment he touched them he said they were scissors, and
seemed delighted with the discovery. On being shown a
guinea at the distance of 15 inches from his eye, he said it
was a seven shilling piece, but placing it about 5 inches from
his eye, he knew it to be a guinea; and made the same mis-
take, as often as the experiment was repeated.

From this time he was constantly improving himself by
looking at, and examining with his hands, every thing
within his reach, but he frequently forgot what he had learnt.

Ou

CHILDREN BORN BLIND RESTORED TO SIGHT. 105

On the loth I saw him aguin, and I told him his eye was so j^^JjJJ
- well, that he might gfb about as he pleased without leaving ation,
the room. He immediately went to the window, and called
out, " What is that moving ?" 1 asked him what he thought
it was: lie said, " A dog drawing a wheelbarrow. There
is one, two, three dog« drawing another. How very pretty !"
These proved to be earts and horses on the road, which he
saw from a two pair of stairs window.

On the 19th, the different coloured pieces of card were
separately placed before his eye, and so little had he gained
in thirteen days, that he could not without counting
their comers one by one tell their shape. This he did with
great facility, running his eye quickly along the outline, so
that it was evident he was still learning, just as a child learns
to read. He had got so far as to know the angles, when
they were placed before him, and to count the number be-
longing to any one object.

The reason of his making so slow a progress was, that
these figures had never been subjected to examination by
touch, and were unlike any thing he was accustomed to see.

lie had got so much the habit of assisting his eyes with
his hands, that nothing but holding them could keep them
from the object.

On the 2Gth the experiments were again repeated on the
couched eye, to ascertain the degree of improvement which
had been made. It was now found that the boy, on looking
at any one of the cards in a good light, could tell the form
nearly as readily as the colour.

From these two cases the following conclusions may be
drawn :

That, where the eye, before the cataract is removed, has General am*
only been capable of discerning light, without being able to cIusK,ns'
distinguish colours, objects after its removal will seem to
touch the eye, and there will be no knowledge of their out-
line; which confirms the observations made by Mr. Chesel-
den :

That where the eye has previously distinguished colours,
there must also be an imperfect knowledge of distances,
but not of outline, which however will afterwards be very
soon acquired, as happened in Mr. Ware's cases. This is

proved

10$ ON VARIOUS SPECIES OK CINCHONA.

proved by the history of the first boy in the present Piper,
who before the operation had no knowledge of colours or
distances, but after it, when his eye had only arrived at the
same stare^ that the second boy's was in before the operation*
he had learnt that the objects were at a distance, and of dif-
ferent colours: that when a child has acquired a new sense*
nothing- but great pain or absolute coercion will prevent
him from making use of it.
Gabraclsin In a practical view, these cases confirm every thing, tiiat

thildren gene- has been stated by Mr. Pott and Mr. Ware, in proof of ca->

hilly soft, and J . . '

touching pro taracts in children being generally soft, and in favour of

ferable to ex- couching, as being the operation best adapted for removing
them. They also lead us to a conclusion of no small im-
portance, which has not before been adverted to; that,
when the cataract has assumed xa fluid form, the capsule,
which is naturally a thin transparent membrane, has to resist
the pressure of this fluid, which like every other diseased
accumulation is liable to increase, and distend it, and there-*
fore the capsule is rendered thicker and more opaque in its
substance, like the coats of encysted tumours in general.
The earlier the As such a change is liable to take place, the earlier the
performed the operation is performed in all children, who have cataracts
betten. completely formed, the greater is their chance of having

distinct vision after the Operation. It is unnecessary to point
out the advantages to be derived from its being done at a
more early age, independent of those respecting the opera-
% tion itself.

VI.

Experiments on Various Species of Cinikona: by Mr.
Vauquelin*.

fceVeral kinds VO EVERAL different kinds of cinchona are met with in

of iJ r, vian ^ shops, but the chief and most in use are the following
bark in the r ' ~

?ho;>s three. First that formerly called by the vague nameof Peruvi-

'ree an b;>rk, and white appears to be taken from the cinchona of*

iicinahs L. This is externally of a gray colour, and inter-

thief.

The common :

Abridged from the Annates de Chimie, vol. LIX, p. 1 13, Aug. 1306.

nally

ON VARIOUS SPECIES OF CINCHONA. J 07

nally of a pale red; thin, and convoluted from the contrac-
tion of the inner surface; smooth and us it were resinous in
its fracture, but sometimes slightly iibrous; and of an as-
tringeut and bitter taste. Its powder is fawn coloured,
mingled with a tinge of gray.

The second, known by the name of red bark, and some- the red»
times erroneously called in France quinquina pitton, is of
a much deeper coiour ; commonly very thick; little if at all
convoluted; fibrous, and not at all resinous in its fracture;
with an astringent and very slightly bitter taste.

The third, or yellow bark, which is of most recent date, the yellow.

must not be confounded with the Angustura bark, as is

sometimes done by the French druggists. This is of a pale

yellow colour ; of a more bitter but less astringent taste than

either of the preceding; partly woody, partly resinous in its

fracture; and a little convoluted, according as it is more or

less thick.

It would be of important service to the physician, as well No ready me-
, i ■/» i i i thod of <lis-

as to the merchant, it there were any sure and simple me- tinguishine
thods of distinguishing the good kinds of cinchona from, their goodness,
such as are bad or damaged : but hitherto we have nothing
to guide us except their appearance, which may be fallaci-
ous, and our judgment from which must depend on our in-
dividual skill and practice. Mr. Seguin indeed has said, Seguin mis-
that the aqueous infusion of the good kinds possesses ex- laken.
clusively the property of precipitating infusion of tan, and
that of the bad of precipitating animal gelatine; but this is
an errour, for there are several species of true cinchona, that
do not precipitate tannin, and yet cure fever*.

I have compared the physical and chemical properties of
the infusions of every kind of cinchona to be found in the
shops, to which I have added that of some other vegetable
substances, apparently analogous with cinchona, and which
are said to have cured fever. The infusions were prepared
with the same quantity of water, the same quantity of bark,
at an equal temperature, and for an equal time, so that no
difference could arise from the mode of preparation.

* Our readers will recollect, that Seguin fancied he had discovered the
febrifuge principle in cinchona to be nothing more or less than gelatine.
See Journal, Vol. VI, p. 13G.

Spec*

108 ON VARIOUS SPECIES OF CINCHONA.

Spec. 1. Ye/hir hark.

Infusion of 122 grammes, or near 4oz troy, of this bark, infused for

* twenty-four hours in two litres [a little more than 2 wine

quarts] of water at 12° [54*6° F.], imparted to it a yellow

colour, and a very hitter and slightly astringent taste.

Tested with va- This infusion occasioned a very copious flocculent precipi-
rious reagents. ... , .. r • • i

° tate in a solution or isinglass.

In a solution of sulphate of iron it produced a green co-
lour resembling that of bile, and some time after a precipi-
tate of the same colour fell down.

The solution of antimoniated tartrite of potash was preci-
pitated by it of a yellowish white.

The oxalate of ammonia threw down from it a precipitate,
which was oxalate of lime.

Lastly it very evidently reddened tincture of litmus.

This infusion, when completely precipitated by a solution
of isinglass, and filtered, was deprived of colour, and scarcely
at all astringent, but it retained its bitterness. In this state
mixed with a solution of sulphate of iron, it turned it green
as before, except that the colour inclined more to a yellow.
It still precipitated the solution of emetic tartar, with this
difference, that the precipitate was whiter. This cannot be
ascribed to an excess of the isinglass, for a solution of isinglass
occasions no change in that of emetic tartar.

Another portion of the infusion, being completely precipi-
tated by emetic tartar and liltered, still rendered the solu-
tions of isinglass and sulphate of iron turbid, but much less
than before. The precipitate formed by the emetic tartar
was turned slightly green by the addition of a few drops of
sulphate of iron.
Principle that ^ W011^ appear from these experiments, that the principle
precipitates which precipitates emetic tartar, isinglass, and sulphate of

nvmv d^tfrrent ir0n> is the Same ! anf* that' I* tllG 1^U°r St'lU ****** tbe pi'°"
ri-om that perty of precipitating isinglass and sulphate of iron, it is be-

irli precipi. cnuse jt retains some portions of the combination of this
principle with antimony. This supposition however is not
reconcilable with the very copious precipitation of isinglass
by certain kinds of cinchona, that do not precipitate emetic
tartar. The principle >that precipitates isinglass therefore

must

Ifctcs gelatine.

ON VARIOUS SPECIES OF CINCHONA. |0A

must he different from that which decomposes tartarised
antimony.

The hark left after this infusion being boiled in water, the Residuum de-
decoction Had utmost exactly the same effects on the reagents cocte<*'
above enumerated: the only difference between them was,
that the decoction became turbid on cooling, furnished a
smaller quantity of precipitate, and this separated from the
liquor more speedily.

I have to add, that both of them threw down from the so- with other
lotion of sulphate of copper a reddish yellow precipitate, and reagents
from that of acetate of lead a yellowish white.

Spec. 2. Santa Fe bark.

This bark, which is lately introduced, has been found to Santa Fe bark,
possess the febrifuge power by able physicians. It is gray on
the outside, red within, thick, little convoluted, with an as-
tringent and slightly bitter taste. Its infusion is much red-
der than that of the yellow bark. Tried in the same manner
it produced the following effects.

With the solution of isinglass it gives a very copious red- r* .• -*u

1- in • • rm • /*» . Its aCtiOU With

dish nocculeut precipitate. Tins effect, which has never yet reagents.
been mentioned by any person to rny knowledge, is worthy
of remark.

It occasioned no change in solution of emetic tartar, in
which it differs from the yellow bark.

It throws down a nne deep green precipitate from solution
-of sulphate of iron; perceptibly reddens tincture of
litmus; is precipitated by oxalate of ammonia, but the
oxalate of lime it thus yields is much less than that from
the yellow bark.

It precipitates acetate of lead and sulphate of copper of a
reddish brown.

The principle which precipitates emetic tartar appears to rts diftVene*

be wanting in this bark: and a farther proof of its differ- from yellow'

ing in some respects from the yellow bark is, that their infu- h"uk'

sions on mixture become turbid.

The decocthm of this species produced the same effects ^
• i .... Decoction,

with reagents as its infusion : but it is observable, that it does

not grow turbid on cooling.

Spec.

110 6X VAV10US SPECIES OF CINCHONA.

Spec. 3. Gray Lark, called super fine.
Gray bark. The infusion of this species ib nearly colourless. lis taste

is bitter ami astringent.
its action with It forms a very copious white precipitate with isinglass, a
i»agent.% rfccj w^jj jnfu<jion 0f tan, a copious and white with emetic

tartar, ami a very fine emerald green with sulphate of iron.

It produces no change in infusion of yellow b.irk.

Spj'C 4. Cinnamon gray bark.

Cinnamon The infusion is of a deep red, and has a bitter astringent

&rar- taste.

its action with It precipitates solution of isinglass of a brown fawn colour,

reagents. gives a green colour with sulphate of iron, but does not pre-

cipitate emetic tartar.

It occasions no change in the infusion of the gray bark,
but it produces a brown precipitate with that of the yellow
bark, and does not precipitate the infusion of tan.

Gelatine and These vegetable infusions, after having precipitated each

tanansed arm- otner as completely as possible, act no longer on emetic tar-

mony precipi- . . " .

tated by differ- tar: whence it follows, that the principle in the inlusion of
pnncip es. yP]jow ^ai.^ which precipitates this salt combines with some-
thing in the infusion of cinnamon gray bark and tan. But
these infusions, thus precipitated, still throw down an abun-
dant precipitate from solution of isinglass, whence it follows,
that these two substances are precipitated by different prin-
ciples.

Precipitate The precipitate formed by mixing the infusions of the 1st

from spec. 1 am] ^ Specjes drjes easily, swells up when heated, gives out
and 4» ' '

a smoke devoid of acrimony, and having some analogy to

that of animal substances, and leaves a light spongy coal.
Spec. 5. Ilcd bark, called pit ton in the shops.

Red bark. ^ n^s ]S erroneously, named, for the true pitton bark has dif-

ferent characters, as will be seen farther on.

Its infusion has a light orange red colour, and an astringent
bitter taste.
Its action with ^ f°rnis a copious reddish precipitate with isinglass, yel»
«gen lowisb white with emetic tartar, brown with the infusion of

the

ON VARIOUS 3FECIES OF CINCHONA. J J J.

the cinnamon gray bark, oriv.n with sulphate of iron. On
the other metallic solutions it acts like other species of cin*
chona.

Spec. 6. Gray bark.

This, which I had from Mr. Bouillon Lagrange, was very Qraybarfc,
thin and convoluted ; and apparently from twigs or very
young trees of the Loxa bark, which will be mentioned fur-
ther on.

The infusion of this species had the red colour of Malaga lis action \yUfo
wine, and an astringent bitter taste. It gave a copious white rea8e- $•
precipitate with isinglass, reddish yellow with infusion of tan,
gray with infusion of yellow bark, yellowish white and floc-
culent with emetic tartar, green with sulphate of iron, white
with acetate of lead.. It did not precipitate sulphate of cop-
per, or infusion of Santa Fe bark. It must possess thefebri- Highly fehfj*
fuge property in a high degree. ?%Q-

Spec. 7- Flat gray hark*.

The infusion of this bark has the colour of Malaga wine, Flat gray barfe.
•and a flat taste, without any astringency or bitterness.

From the infusion of yellow bark it throws down a copious, jts action ^\\\\
brown, flocculent precipitate. To the solution of red sul- ^S?^?
phate of iron it gives a fine green colour, and in a 'few mi-
nutes a precipitate of the same colour is thrown down. Nei-
ther tartarised antimony, isinglass, nor cinnamon gray bark
produces any change in its infusion.

These appearances indicate, that it is not a true cinchona; Not a cmcl>9*
or, if it belong to the genus, at least it has not its chemical na»
properties ; whence we may presume, that it does not possess
the same medicinal virtues.

Spec. 8 . Yellow [ w h i te] bark, cinchona pubescens of Vahl.

A hundred grammes of this bark in fine powder macerated white bark,
four and twenty hours in distilled water afforded a transparent
liquor of it golden yellow colour, very bitter, and frothing

* This appears to be the white cinchona of Santa Fe brought oyer by
Mr. von Humboldt, which will be noticed further on.

when

112 ON' VARIOUS SPECIES OF CINCHONA.

when shaken. Willi reagents it exhibited the following ap-
pearances.
Its action with Tincture of gaits formed in it a copious precipitate, which
ias' an excess of the tincture redissolved, and the addition of

water again threw down. This shows, that the matter sepa-
rated by the tannin is not pure!)' animal.

From the solutions of tartarised antimony and nitrate of
mercury it threw down a yellowish white precipitate. To
that of sulphate of iron it gave a decided green colour, but
nothing fell down. Solution of isinglass pruduced no change
in it. It did not redden infusion of litmus.
Ueposite from During evaporation this infusion deposited a rosocoh.ured
't« -substance on the sides of the dish; and being reduced to the

consistence of a sirup, it deposited farther on cooling a fresh
quantity of a chesnut-brown substance. The filtered liquor
was stiil coloured, and contained the salt peculiar to cincho-
nas, which will be noticed hereafter.

The brown substance, washed with a small quantity of cold
water, is soluble in warm water and in alcohol ; but very spa-
ringly in cold water. Its taste is very bitter.

In the aqueous solution of this sediment nutgalls form a
copious precipitate. Tartarised antimony and nitrate of
mercury produce the same effects in this solution as in the
infusion of the bark itself. Sulphate of iron is turned green
by it. Oxigenized muriatic acid loses its smell when poured
into the solution, and presently forms a flocculent precipitate.
Isinglass has no effect on it: it is not changed by sulphuric or
acetic acid : and when diluted with caustic potash it gives out
no smell of ammonia.

Two bundled and twenty-five grammes [3475 grs.] of this
substance, weighed when dry, afforded on distillation a great
deal of water, a perceptible quantity of ammonia, and a pur-
ple oil, which loses this Co) our on being dissolved in alcohol,
but resumes it as the menstruum evaporates by being left
exposed to the air.

They left in the retort 11 decig. [17 grs.] of coal, which
yielded by incineration 1 dec. [1'olgrs.] of ashes soluble
With effeivescence in muriatic acid, and the solution of which
yielded lime and iron.

ft

ON VARIOUS SPECIES OF CINCHONA. ]J3

It is evident from what has been seen, that it is this Co- Thisa mean
loured, bitter substance, which, in the maceration of the cin- ^a^nd^-
chona in question, produces with reagents all the phenomena table matter,
mentioned above. This substance seems to be a medium, in
its nature and properties, between vegetable and animal sub-
stances. Probably it is the eilicacious principle in the cure of Probably the

,. , i- 1 i i- .i • l c febrifuge prin-

intermittent fevers. I he liquor separated from this substance ci lc> *

was treated with alcohol, which took up the colouring mat-
ter; and this proved to be nothing but a portion of the same (
substance, that the water had retained. The portion insolu-
ble in alcohol was of the consistence of a thick mucilage, and
had scarcely any taste or colour. It dissolved in large quan-Salt of bark,
tity in water; and the solution yielded by spontaneous evapo-
ration slightly coloured and lamellated crystals of a salt,
which will be farther noticed in the sequel.

The same portion of cinchona, when it had been macerated
for the seventh time, still giving a precipitate with galls, I con-
ceived, that the cold water had been incapable of dissolving
the whole of the principle, by which this effect was produced.
In consequence I boiled the residuum of the cinchona, and Residuum de-
the liquor thus obtained exhibited the same phenomena as cocted.
the infusion, except that it did not precipitate the solution of
Urtarised antimony, probably because it was too much di-
luted with water.

This bark therefore is not the same as species 1, though
they are both called by the same name.

Spec. 9« Common bark, cinchona officinalis.

Eighty-four grammes [1297 grs.] of this bark, treated Common bark
like the preceeding, afforded a paler coloured liquor, and of tfte sho!JS*
more mucilaginous, though equally bitter. This infusion its action with
slightly reddened that of litmus. With other reagents it ex- ^agents.
hibited similar phenomena to the cinchona pubescens.

All the liquors obtained by maceration when evaporated
afforded a sediment, the properties of which so much resem-
bled those of the same substance from the cinchona pubes-
cens, that I conceived they might be mixed together: but the
supernatant liquor, containing the salt essential to cinchona,
was evaporated separately, and set to crystallize by sponta-

Vol. XIX. Feb. 1808. i neous

114 ON VARIOUS SPECIES OF CINCHONA.

neons evaporation, after the colouring matter had boon sepa-
rated by alcohol, and in a few days crystals were produced
from it.

Thus we have two species of cinchona, which do not preci-
pitate isinglass, and which are consequently destitute of the
principle, that produces this effect in other species. Accord-
ing to Mr. Seguin they are to be classed among the best sorts.

After several washings with cold water, as galls still occa-
sioned a precipitate, the residuum was treated with hot water,
which acquired a pretty deep colour. This was less bitter
than the liquor obtained by maceration, and still more muci-
laginous than the decoction of the cinchona pubescens. It
formed a precipitate with galls and nitrate of mercury, and
• turned green with sulphate of iron ; but neither tartarised
antimony nor isinglass occasioned any change it it.

This species therefore is not the same with that examined
above by the name of gray, and called superfine.

Spec. 10. Large-leaved bark, cinchona magnifolia.

Lar^e-leavcd A hundred grammes of this bark in fine powder, macerated
tark- for twenty-four hours, yielded a solution that did not pass the

filter easily. It was of a ruby red colour, little mucilaginous,
slightly bitter, and very decidedly astringent.
Its action with This infusion did not redden that of litmus: neither galls
nor tartarised antimony afforded any precipitate with it : with
solution of isinglass it gave a copious precipitate: sulphate of
iron gave it the green hue of oxide of chrome, which muri-
atic acid converted into a dirty green. With the infusions of
the eigbth and ninth species it gave a precipitate.

The water in which it was steeped cold a second time did
not precipitate isinglass.

The several waters in which it had been macerated were
evaporated to the consistence of an extract, and treated with
hot alcohol, which acquired from it a very fine colour. This
alcoholic solution diluted with water, and tested with the rea-
gents employed with the first water in which it had been
macerated, exhibited the same results. The matter there-
fore, that produced the effects above enumerated, is soluble in
alcohol.

The

ON VARIOUS SPECIES OF CINCHONA. ]]5

The part not soluble in alcohol was of an ochre red, and Portion not so-
blackcned by exposure to the air. It was redissolvable in llol<
water; and its solution precipitated neither isinglass nor galls:
but it precipitated tartarised antimony and nitrate of mercury,
and turned sulphate of iron green.

Ten grammes [154f grs.] of this substance insoluble in
alcohol being distilled afforded ammonia, and a coal that
weighed 41 cent. [0| grs.]

A bark sold me without any name*.

A hundred grammes of this bark macerated for twenty- Another spe-
four hours did not give the water so deep a colour as the pre- ^thepreceed-
ceeding species, and its astringency was less, but it was more ing.
bitter.

It perceptibly reddened infusion of litmus; precipitated
neither with galls nor tartarised antimony ; but formed a pre-
cipitate with isinglass and nitrate of mercury, and turned
sulphate of iron green.

This species exhibited all the characters in general of the
preceding, and should be placed in the same class.

The decoction of the residuum showed no difference from
the infusion.

Spec. 11. True pit ton bark.

This species, which was given me by Mr. Solome, an emi- Pittontark.
licnt apothecary in Paris, greatly resembles in colour, form,
and bitterness the cinchona of St. Domingo, which was ana-
lysed by Mr. Fourcroy about fifteen years ago.

A hundred grammes of this bark, treated like the other,
imparted to the water a red colour like that of venous blood.
Its taste is more bitter and disagreeable than that of the If* action with
others. Tincture of galls, tartarised antimony, nitrate of re fce
mercury, and sulphate of iron, produced copious precipitates
with this infusion of cinchona. Isinglass produced no change
in it. It was precipitated by oxigenised muriatic acid, but by
no other.

The infusion left by evaporation a residuum, which partly
dissolved in alcohol, communicating to it a fine red colour.

* Jt had all the characters of the cinchona magnifolia [grandifolia].
I 2 The

}\Q ON VARIOUS SPECIES OF CINCHONA.

The portion not soluble in alcohol had a gray colour and
earthy appearance. It yielded ammonia on distillation. The
portion dissolved exhibited the same phenomena as the in-
fusion from which it was obtained.

Cinchona of different kinds brought from America
by Messrs. von Humboldt and Bonpland.

Spec. 12. Bark of Loxay taken from branches of the second
year, and used by the apothecary to the king of Spain.

Loxabaik. TJ»W is externally gray, internally yellow, thin, convo-

luted, and bitter and astringent to the taste.

Eight grammes of this bark, infused for twenty-four hours
in 150 grammes of water at 15° [59° Fj, yielded a reddish
yellow liquor not very deeply coloured, having a slightly
Its action with mouldy smell, and a bitter taste. It precipitated galls, tar-
reagents, tarised antimony, and acetate of lead of a yellowish white,
iron of a blueish green, oxalate of ammonia white, and
isinglass in large, white, glutinous flocks. The precipitates
formed by tartarised antimony and isinglass redissolved in an
excess of the hot infusion.
Highly febri- From these properties this cinchona must have great fe-
Juge. brifuge virtue.

Spec. 13. White lark of Santa Fe,

White bark of This bark has a rusty yellow colour externally, which is

Santa Fe. deeper within. It is flat and thick. Its fracture is granu-

lated nearly like that of beech bark. Its taste is neither bit-
ter nor astringent like that of the other barks.

Eight grammes macerated for twenty-four hours in 150
grammes of water imparted to it a deeper yellow colour than

Its action with the Loxa barks. This infusion precipitated neither galls,
tartarised antimony, nor isinglass; it turned solution of iron
green ; and precipitated acetate of lead of a brownish yellow.

Notacincho- From these properties this bark appears not to be a trne
cinchona.

Spkc. 14. Orange-coloured bark of Santa Fe.

Orange co- This bark is of a cinnamon yellow colour, without any

loured bark of epidermis, thick, and very fibrous in its fracture. The thin-
Santa Fe. r

nest

OX VARIOUS SPECIES OF CINCHONA. 117

nest pieces are convoluted, the thickest flat. It is not at all

astringent.

Its infusion, made as above, is scarcely coloured; has a Its act'on Wlth

A . . . reagents.

decidedly bitter taste; forms a eopious white precipitate with

tartarised antimony; precipitates tannin, but not isinglass ;
turns iron slightly green ; and does not render the infusion
of Loxa bark turbid. This species of cinchona differs from Of little virtue,
that of Loxa, and cannot have very striking febrifuge pro-
perties.

Spec. 15. Common peruvian bark.

This bark is gray externally, and of an ochre red within-. Common bark,
its surface is wrinkled; it is convoluted, and of various thick-
nesses according to the difference of the pieces; its taste is
bitter and astringent.

Eight grammes, macerated for twenty-four hours in 150
grammes of water, gave it a light yellow colour, and a fitter
and astringent taste. This infusion precipitated tartarised Its action with
antimony, isinglass, and tannin of a yellowish white, and reagen^.
sulphate of iron green. It reddened litmus paper.

This bark appears to be the same with the gray, called An excellent
superfine, spec. 3. From the properties it exhibited it must febniu£e-
be excellent in fevers, &c.

Spec. lG. Red bark of Santa Fe.

This does not appear to differ in any sensible degree from Red bark of
that mentioned above by the name of Santa Fe bark, spec. 2. 'Sullte *e*

Eight grammes, macerated as above, gave an infusion of Tts action with
the red colour of Malaga wine, with an astringent taste, and reagents.
but little bitterness. It precipitated isinglass brown ; gave
no precipitate with tannin or tartarised antimony ; turned
sulphate of iron green; and slightly reddened litmus paper.
These chemical properties are equally apparent in the Santa
Fe bark described above.

Spec. 17. Yellow bark of Cuenqa, from branches of four or
six years old.

This bark is gray exteriorly, covered with a white lichen, Yellow bark #f
of a brown yellow interiorly, having a fibrous fracture, and Cuenca.
scarcely any taste. Its infusion is neither bitter nor astrin-
gent.

J ] g ON VARIOUS SPECIES OF CINCHONA.

gent. It precipitates neither tartarised antimony, isinglass,
nor tannin; merely turns sulphate of iron green; but preci-
pitates acetate of lead.
Not febrifuge. It can have no febrifuge virtue.

Table of the
properties of
the barks
brought over
by von Hum-
boldt.

5

S

IB

o

K

%

■a

en
O

<

%

W

V5

CQ
O

« .

-W P

SB

bc.ti

c —

•c «

-«-> -

tT'P

<

Red colour ot Malaga
wine: littlebitterness,but
astringent to the taste.

Neither bitter nor astrin-
gent. Precipitates ace-
tate of lead.

O 0)

is

si

Pretty deep yellow colour.
Neither bitter nor astrin-
gent. Precipitates ace-
tate of lead.

Taste decidedly bitter,
slightly astringent. In-
fusion light coloured.

h

s

<

H
0

X

iJ

5

i

"EL
*S

U

ft- a;

o

a
o

p

0

i

'ft-.
'3

•
ft <y

c

i

o
fe

*£L
'5

CJ

a.£

en ctf

P ■*>
O

'ft,

o

£ 3
t ©

b£>"o

LI

1

p

Oj n~;

0

i

p

o

1

p

cu no

0"

q3
g

c

O

p
O
fe

en

J!

H

q3
p
o

0)
en "ti

- is
.2-?

If

^ ft.

3 ,tS

.o a-

0

0)

c

0- •
en -w

C

Q

a

o

Copious pre-
cipitate.

p

o

125

P
o

00

W

ft.

Common gray
Peruvian bark.

Red bark of
Santa Fe.

3

Vellow bark
of Cuenca.

4

King of Spain's
Loxa bark.

5

White bark of
Santa Fe.

6

Yellow bark
of Santa Fe.

T#

ON VARIOUS SPECIES OF CINCHONA. 1 ]0,

To gain some additional light respecting the nature of the Other sub-
principles contained in cinchona, I instituted a comparative parg^withdn-
examination of several other vegetable substances, that ap- chona.
pear to have some analog}' with it, and the composition of
which is a little better known ; such as galls, oak, bark,
Angustura bark, and some others.

Natgalls.

The infusion of this substance copiously precipitated i sin- Galls,
glass white; iron, blue; tartarised antimony, yellowish
white; infusion of yellow bark, in dirty white flocks; cop-
per, brown yellow ; and lead, yellowish white.

It did not precipitate infusion of Santa Fe bark, or of
tan.

The infusion of nutgalls therefore, like that of yellow
bark, contains the principle that precipitates isinglass with
that which precipitates tartarised antimony; and in this re-
spect they resemble each other. But they differ with regard
to the principle that acts on tan and on iron, since their me-
tal is precipitated green by cinchona, and blue by galls.
They differ too in another point, since they mutually preci-
pitate each other.

Tan.

The infusion of this substance, made with the same care Oak bark.
and in the same proportions as those of the cinchona bark,
precipitated solution of isinglass yellowish; iron blue; cop-
per, brown : but it occasioned no change in solution of Santa
Fe bark, or solution of tartarised antimony. It reddened
infusion of litmus, and was precipitated by oxalate of am-
monia.

Hence we see, that oak bark, does not contain the sub-
stance that precipitates tartarised antimony, as nutgalls, yel-
low bark, and some other barks do; and in this respect it
differs from them, though they agree in precipitating isin-
glass.

Cherry-tree bark.

This bark, which has sometimes been fraudulently sub- Bark of the
stituted for that of cinchona, has nothing in common with ch"rry-tlf'«

» it

120 ON VARIOUS SPFCIES OF CINCHONA.

it except the property of forming a green precipitate with
solution of sulphate of iron. It occasions no change in isin-
glass, tartarised antimony, or decoction of oak bark. It£
possessing any febrifuge property therefore is very question-
able.

Centaury and Germander.

Centaurea and These two plants afforded me the same results as cherry-
chamicdrys. tree bark: their efficacy in fever therefore is equally doubt-
ful.

White willow bark.

Bark of the This bark, to which febrifuge virtues have formerly been

white willow, ascribed, possesses in fact some of the chemical properties
of certain species of cinchona, namely those of precipitating
isinglass, and throwing down sulphate of iron green, and
acetate of copper brownish. The white willow bark, there-
fore, as it unites the bitter' and astringent tastes, may possi-
bly be a febrifuge.

Angustura
bark.

Angustura bark.

The infusion of this bark does not precipitate isinglass:
but it forms a copious precipitate with infusion of nutgalls,
and with that of yellow bark, though it merely renders in*
fusion of Santa Fe bark slightly turbid.

It precipitates iron, tartarised antimony, copper, lead, and
infusion of tan, all yellow.

This bark, we see, differs from several of the species of
cinchona, and from the other substances submitted to the
comparative examination, in not precipitating animal gela-
tine. It wants too the astringent taste, but on the other
hand is extremely bitter. There is reason to believe too,
that the principle, which in this precipitates the metallic so-
lutions, is not altogether the same with that in the cincho-
nas; at least the colour of the precipitates it gives is very
different. From these properties however the Angustura
bark may possibly be a febrifuge.

(To be concluded in the next number.)

Experiments

irER^CHEL ON COLOURED RINGS. 121

VII.

Experiments Jbr investigating the Canse of the coloured con-
centric Rings, discovered by Sir Isaac Newton, between
two Object-Classes laid upon one another. By William
Herschel, £ZD. F.R.S*.

XhE account given bv Sir I. Newton of the coloured Coloured rings
P Sir I. Newtou

arcs and rings, which he discovered by laying two prisms or supposed,

object-p-lasses upon each other, is highly interesting. He may Iea? to *

. . , , oj-mi completion of

very justly remarks, that these phenomena are " or difficult the theory of

consideration," but that " they may conduce to farther dis- llSht'

coveries for completing the theory of light, especially as to

the constitution of the parts of natural bodies on which

their colours or transparency dependf."

With regard to the explanation of the appearance of His explana-
these coloured rings, which is given by Sir I. Newton, I unSitaheUKr*
must confess, that it has never been satisfactory to me. He
accounts for the production of the rings, by ascribing to the
rays of light certain fits of easy reflection and easy trans-
mission alternately returning and taking place with each ray
at certain stated intervals}. But this, without mentioning
particular objections, seems to be an hypothesis, which can-
not be easily reconciled with the minuteness and extreme
velocity of the particles, of which these rays, according to
the Newtonian theory, are composed. i

The great beauty of the coloured rings, and the pleasing Dr Herschel
appearances arising from the different degrees of pressure of ^ s^ect u>
the two surfaces of the glasses against each other when they some extent.
are formed, and especially the importance of the subject,
have often excited my desire of inquiring farther into the
cause of such interesting phenomena; and with a view to
examine them properly I obtained, in the year 1792, the two
object-glasses of Huygens, in the possession of the Royal
Society, one of 122, and the other of 170 faet focal length,
and began a series of experiments with them, which, though

• From the Phil. Tran?. for 1807, Part 111, p 180.
f Newton's Optics, 4th ed. p. 169. J Ibid. p. 256.

many

12$

J I is experi-
Inents led to

hew conclusi-
ons, and discri-
minations.

Minute detail
necessary.

*Ferm modifi-
cation.

HKRSCIIEL ON COLOURED KINGS*

tnany times interrupted by astronomical pursuits, has ofterl
been taken up again, and has lately been carried to a very
considerable extent. The conclusions that may be drawn
from them, though they may not perfectly account for all
the phenomena of the rings, are yet sufficientl)- well sup-
ported, and of such a nature as to point out several modifi-
cations of light that have been totally overlooked, and others
that have never been properly discriminated. It will, there-
fore, be the aim of this paper to arrange and distinguish the
various modifications of light in a clear and perspicuous or-
der, and afterwards to give my sentiments upon the cause
of the formation of the concentric rings. The avowed in-
tricacy of the subject*, however, requires, in the first place,
a minute detail of experiments, and afterwards a very gra-
dual developement of the consequences to be deduced from
them.

As the word modification will frequently be used, it may
not be amiss to say, that when applied to light, it is intended
•to stand for a general expression of all the changes that are
made in its colours, direction, or motion: thus, by the mo-
dification of reflection, light is thrown back; by that of re-
fraction, it is bent from its former course; by the modifica-
tion of dispersion, it is divided into colours, and so of the rest.

I. Of different Methods to make one set of concentric Rings
visible.

One set of rings
made visible
by different

methods.

In the beginning of my experiments 1 followed the New-
tonian example, and, having laid the two object-glasses of
Huygens upon one another, I soon perceived the concentric
rings. It is almost needless to say, that I found all the
Newtonian observations of these rings completely verified ;
but as his experiments seemed to be too much confined for
drawing general conclusions, I endeavoured to extend them :
and by way of rendering the methods I point out very clear,
I have given one easy particular instance of each, with the
addition of a generalization of it, as follows:

First Method, On a table placed before a window I laid

down a slip of glass, the sides of which were perfectly plain,

neof<dai. parallel, and highly polished. Upon this I laid a double

* Newton's Optics, 4th ed. p. 288$ end of Obs. 12.

convex

-1st method.
Double eon
vex lens on a

HERSCHEL ON COLOURED RINGS. \<*§

convex lens of 20 inches focal length, and found that this
arrangement gave me a set of beautiful concentric rings.

I viewed them with a double convex eye lens of 2f inches
focus mounted upon an adjustable stand, by which simple ap-.
paratus I could examine them with great ease; and as it was
not material to my present purpose by what obliquity of in-»
eidence of light I saw the rings, I received the rays from the
window most conveniently when they fell upon the lens in an
angle of about 30 degrees from the perpendicular, the eye
being; placed on the opposite side at an equal angle of eleva*
vation to receive the reflected rays.

Generalization. Instead of a plain slip of glass, the plain Generalize
side of a plano-concave, or plano-convex len6 of any focal ti0n»
length whatsoever may be used : and when the convex side
of any lens is laid upon it, whatever may be the figure of
the other surface, whether plain, concave, or convex, and
whatever may be its focal length, a set of concentric rings
will always be obtained. I have seen rings with lenses of
all varieties of focus, from 1?0 feet down to one quarter of
an inch. Even a common watch glass laid upon the same
plain surface will give them.

To insure success, it is necessary, that the glasses should Necessary ptp,
be perfectly well cleaned from any adhering dust or soil, cautl0U^
especially about the point of contact; and in laying them
upon each other a little pressure should be used, accompan-
ied at first with a little side motion, after which they must
be left at rest.

If the surface of the incumbent lens, especially when it

is of a very short focal length, is free from all imperfection

and highly polished, the adjustment of the focus of the

above mentioned eye-glass, which I always use for viewing

the rings, is rather troublesome, in which case a small spot

of ink made upon the lens will serve as an object for a sufhv

cient adjustment to find the rings.

Second Method. Instead of the slip of glass, I laid down ,.

v & 2d method.

a well polished plain metalline mirror; and placingupon it Double con-

the same 26-inch double convex lens, I saw again a complete vex lens nn *

,. ° L metallic miir

set ot concentric rings. ror<

It is singular that, in this case, the rings reflected from a

bright metalline surface will appear fainter than when the

I same

124

HF.RSCHEL ON COLOURED RINGS.

Generaliza-
tion.

3d method.
Double convex
lens on a pia-
no convex.

4th. The samp
on convex me
tal.

Generaliza-
tion.

5th. Double
convex lens in
a double con-
cave glass.

same lens is laid on a surface of glass reflecting- but littt*
light, this may however be accounted for by the brilliancy
of the metalline ground, on which these faint rings are seen,
the contrast of which will orFuscate their feeble appearance.

Generalization. On the same metalline surface every va-
riety of lenses may be laid, whatever be the figure of their
upper surface, whether plain, concave, or convex, and what-
ever be their focal lengths, provided the lowest surface re-
mains convex, and concentric rings will always be obtained ;
but for the reason mentioned in the preceding paragraph,
very small lenses should not be used, till the experimentalist
has been familiarized with the method of seeing these rings,
after which lenses of two inches focus, and gradually less,
may be tried.

Third Method. Hitherto we have only used a plain sur-
face, upon which many sorts of glasses have been placed ; in
order therefore to obtain a still greater variety, I have laid
down a plano-convex lens of 15 inches focal length, and upon
the convex surface of it I placed the 26-inch double convex
lens, which produced a complete set of rings.

Fourth Method. The same lens, placed upon a convex
metalline mirror of about 15 inches focal length, gave also a
complete set of rings.

Generalization. These two cases admit of a much greater
variety than the first and second methods ; for here the incum-
bent glass may have not only one, but both its surfaces of
any figure whatsoever; whether plain, concave, or convex ;
provided the radius of concavity, when concave lenses are
laid upon the convex surface of glass or metal, is greater
than that of the convexity on which they are laid.

The figure of the lowest surface of the subjacent substance,
when it is glass, may also be plain, concave, or convex ; and
the curvature of its upper surface, as well as of the mirror,
may be such as to give them any focal length, provided the
radius of their convexities is less than that of the concavity of
an incumbent lens; in all which cases complete sets of con-
centric rings will be obtained.

Fifth Method. Into the concavity of a double concave
glass of 8 inches focal length I placed a 7-inch double con-
vex lens, and saw a very beautiful set of rings.

Sixth

HERSCIIEL ON COLOURED RINGS. 125

Sixth Method. Upon a 7 feet concave metalline mirror I
placed the double convex 20-inch lens, and had a very line
6et of ring's.

Generalization. With these two last methods, whatever Gth. Lens in
may be the radius of the concavity of the subjacent surface, collcave meta^
provided it be greater than that of the convexity of the in-
cumbent glass; and whatever may be the figure of the up-
per surface of the lenses, that are placed upon the former,
there will be produced concentric rings. The figure of the
iow est surface of the subjacent glass may also be varied at
pleasure, and still concentric rings will be obtained.

II. Of seeing Rings by Transmission.

The great variety of the different combinations of these Rino-s by trans-
differently figured glasses and mirrors will still admit of far- mission,
ther addition, by using a different way of viewing the rings.
Hitherto the arrangement of the apparatus has been such,
as to make them visible only by reflection, which is evident,
because all the experiments that have been pointed out may
be made by the light of a candle placed so, that the angle of
incidence and of reflection towards the eye of the observer
may be equal. But Sir I. Newton has given us also an ob-
servation, where he saw these rings by transmission, in con-
sequence of which I have again multiplied and varied the
method of producing them that way, as follows:

First Method. On a slip of plain glass highly polished on lst met]-,0(1

both sides place the same double convex lens of 2(i-inches, Double convex

which had already been used when the rings were seen by ^ns on plain

& J glass.

reflection. Take them both up together and hold them

against the light of a window, in which position the concen-
tric rings will be seen with great ease by transmitted light.
But as the use of an eye-glass will not be convenient in this
■situation, it will be necessary to put on a pair of spectacles
-with glasses of 5, (i, or 7 inches focus, to magnify the rings
in order to see them more readily.

Second Method. Tt would be easy to construct an appara- od. xi,e same
tusfor viewing the rings by transmisson fitted with a proper with tne Kf&i
eve-glass; but other methods of effecting the same purpose ^'"w! ^"^
are preferable. Thus, if the two glasses that are to give the
rings be laid upon a hollow stand, a candle placed at a pro-
per

12(J HEltSCHEL ON COLOURED RINGS*

per angle and distance under them will show the rings con-
veniently by transmitted light, while the observer and the
apparatus remain in the same situation as if they were to be
seen by reflection.
3d. Daylight Third Method. A still more eligible way is to use daylight

reflected up- received upon a plain metalline mirror reflecting it upwards
ward from a , , * , , • • , • , •

minor. to the glasses placed over it, as practised in the construction

of the common double microscope ; but 1 forbear entering
into a farther detail of this last and most useful way of see-
ing rings by transmission, as I shall soon have occasion to
say more on the same aubp
Generalization. Generalization. Every combination of glasses, that has
been explained in the first, third, and fifth methods of see-
iug rings by reflection, will also give them by transmission,
when exposed to the light in any of the three ways that
have now been pointed out. When these are added to the
former, it will be allowed, that we have an extensive variety
of arrangements for every desirable purpose of making ex-
periments upon rings, as far as single sets of them are
Concerned.

III. Of Shadows.

Of shadows. When two or more sets of rings are to be seen, it will re-

quire some artificial means, not only to examine them criti-
cally, but even to perceive them ; and here the shadow of
Point of a pen- some slender opaque body will be of eminent service. To
teufe cast shadows of a proper size and upon places where they

are wanted, a pointed penknife may be used as follows.
eives two si a- When a plain slip of glass or convex lens is laid down, and
dews from a the point of a penknife is brought over either of them, it will
Vexicliissf>a" cast two sna-dows, one of which may be seen on the hrst sur-
face of the glass or lens, and the other on the lowest.

When two slips of glass are laid upon each other, or a con-
three from two ,. iii- i
glasses, vex lens upon oueshp, so that both are in contact, the pen-
knife will give three shadows; but if the convex lens should
and in some _ . . „ , .. „ . , ,._..
mmoiom, be of a very short focus, or the slips or glass be a little separa-
ted, four of them may be perceived; for in that case there
will be one formed on the lowest surface of the incumbent
s^lass or lens; but in my distinction of shadows this will not
he noticed. Of the three shadows thus formed the second

will

HERSCHEL ON COLOURED RINGS. \OJ

frill be darker than the first, but the third will be faint.
When a piece of looking-, glass is substituted for the lowest
slip* the third shadow will be the strongest.

Three slips of glass in contact, or two slips with a lens Four from
upon them, or also a looking glass, a slip and a lens put toge- three glasses.
(her, will give four shadows, one from each upper surface and
one from the bottom of the lowest of them.

In all these cases a metalline mirror may be laid under Metallic mirror
the same arrangement without adding to the number of sha- renders them
dows, itseifect being only to render them more iutense and dl
distinct.

The shadows may be distinguished by the following me- Method of dis-
thod. When the point of the penknife is made to touch the tinguishing
surface of the uppermost glass or lens, it will touch the point the shadow>»
of its own shadow, which may thus at aey time be easily as-
certained: and this in all cases I call the first shadow ; that
which is next to it, the second ; after which follows the third,
and >o on.

In receding from the point, the shadows will mix together, Mixture of ih«
and thus become more intense; but which, or how many of shadows.
them are united togther, may always be known by the points
of the shadows.

When a shadow is to be thrown upon any required place, precautions
hold the penknife nearly half an inch above the glasses, and
advance its edge foremost gradually towards the incident
light. The front should be held a little downwards to keep
the light from the underside of the penknife, and the sha-
dows to be used should be obtained from a narrow part of it.

With this preparatory information it will be easy to
point out the use that is to be made of the shadows when
they are wanted.

IV. Of two sets of Rings.

I shall now proceed to describe a somewhat more compli- Two sets of
cated way of observation, by which two complete sets of r,nSs«
concentric rings may be seen at once. The new or additi-
onal set will furnish us with an opportunity of examining
lings in situations where they have never been seen before,
which will be of eminent service for investigating the cause
of their origin, land with the assistance of the shadows to be

formed,

128 HERSCHEL ON COLOURED RINGS.

formed, as has been explained, we shall not find it difficult
to see them iu these situations,

1st method. First Method. Upon a well polished piece of good look-

ou e eon vex j^ g]ass ]av down a double convex lens of about i>0 inches

glass: focus. When the eye-glass has been adjusted as equal for

seeing one set of rings, make the shadow of the penknife in
the order which has been described, pass over the lens ; then
as it sometimes happens in this arrangement that no rings
are easily to be seen, the shadow will, in its passage over the
surface, show where they are situated. When a set of them
is perceived, which is generally the primary one, bring the
third shadow of the penknife over it, in which situation it
will be seen to the greatest advantage.

Secondary set Then, if at the same time a secondary set of rings lias

«tf ruigs. not yet been discovered, it will certainly be perceived when

the second shadow of the penknife is brought upon the pri-
mary set. As soon as it has been found out, the compound
shadow, consisting of all the three shadows united, may
then be thrown upon this secondary set, in order to view it
at leisure and in perfection. I>ut this compound shadow
should be taken no farther from the point than is necessary
to cover it; nor should the third shadow touch the primary
set. The two sets are so near together, that many of the
rings of one set intersect some of the other.

,,. , , When a sight of the secondary set has been once obtained,

\ievred alter- » ,

natdy with the it will be very easy to view it alternately with the primary
primary. one by a slight motion of the penknife, so as to make the

third shadow^ of it go from one set to the other.
The rinws made Besides the use of the shadows, there is another way to
■visible by set- make rings visible when they cannot be easily perceived,

mrJiiun!"1 ^ which is to take hold °f the lens wit]l b°th hands> to Press
it alternately a little more with one than with the other; a
tilting motion, given to the lens in this manner, will move
the two sets of rings from side, to side; and as it is well
known that a faint object in motion may be sooner perceived
than when it is at rest, both sets of rings will by these means
be generally detected together.

_.',..■, It will also contribute much to faciliate the method of

Thelicht . ....

should be cbli- seeing two sets of rings, rf we receive the light in a more

*lue- oblique angle of incidence, such as 40, 50, or even GO de-

grees

ITERSCIIEL OX COLOURED RINGS. 129

Gvops. This will increase the distance between the centres of ,

the primary and secondary sets, and at the same time occa-
sion a more copious reflection of light.

Instead of a common looking-glass a convex glass mirror With glasses
may be used, on which may be placed either a plain, a con- of other forms,
cave, or a convex surface of any lens or glass, and two sets of
rings will be obtained.

In the same manner, by laying upon a concave glass mirror
a convex lens* we shall also have two sets of rings.

The generalizations that have been mentioned when one set Generalization.
of rings was proposed to be obtained may be easily applied
with proper regulations, according to the circumstances of
the case, not only to the method by glass mirrors already
mentioned, but likewise to all those that follow hereafter, and
need not be particularized for the future. In the choice of
the surfaces to be joined, we have only to select such as will
form a central contact, the focal length of the lenses and the
figure of the upper surface being variable at pleasure.

Second Method. On a plain metalline mirror I laid a pa- 2d. Lens on
rallel slip of glass, and placed upon it the convex surface 0fglass and metal.
a 17 -inch plano-convex lens, by which means two sets of
rings were produced.

Upon the same minor the plain side of the plano-convex
glass maybe laid instead of the plain slip, and any plain,
convex, or concave surface, being placed upon the convexity
of the subjacent lens, will give two sets of rings.

The plain side of a plano-concave glass may also be placed
upon the same mirror, and into the concavity may be laid any
lens that will make a central contact with it, by which ar-
rangement two sets of rings will be obtained.

Third Method. Upon a small well polished slip of glass 3d. Lens'on
place another slip of the same size, and upon them lay a 39- fc^° s,1t)S'^
inch double convex lens. This will produce two sets of rings;
one of them reflected from the upper surface of the first slip
of glass, and the other from that of the second.

Instead of the uppermost plain dip of glass we mav place
upon the lowest slip the plain side of a plano-convex or
piano-conrave lens, and the same variety which has been ex-
plained in the third method, by using any incumbent lens that
Vol. XIX. Feb. 1S08. K will

130 iMISCHEL ON COLOURED RINGS.

will make a central contact, either with the convexity or

concavity of the subjacent glass, will always produce two sets

of rings.

4th. Lens on Fourth Method. A more refined but rather more difficult

- on black -. - . . . ,. ,, .

paper. wav °* seeiM£ tw° se*s of rings is to lay a plain slip of ixlass

on a piece of black paper, and when a convex lens is placed
upon the slip, there may be perceived, but not without parti-
cular attention, not only the first set, which has already been
pointed out as reflected from the first surface of the slip, but
also a faint secondary set from the lowest surface of the same
slip of glass.

It will be less difficult to see two sets of rings by a reflec-
tion from both surfaces of the same glass, if we use, for in-
stance, a double concave of 8 inches focus with a double cont
vex of 7f inches placed upon it. For, as it is well known that
glass will reflect more light from the farthest surface when air
rather than a denser medium is in contact with it, the hollow
space o.f the 8-inch concave will give a pretty strong reflec-
tion of the secondary set.
•>th. Two pri- Fifth Method. The use that is intended to be made of two
pendent sets of sets °^ r'nSs requires, that one of them should be dependent
rings* upon the other: this is a circumstance that will be explained

hereafter, but the following instance, where two independent
sets of rings are given, will partly anticipate the subject.
When a double convex lens of 50 inches is laid down with a
slip of glass placed upon it, and another double convex one of
26 inches is then placed upon the slip, we get two sets of
rings of different sizes; the large rings are from the 50-inch
glass, the small lings from the 26- inch one. They arc to be
seen with great. ease, because they are each of them primary.
These may be By tilting the incumbent lens, or the slip of. glass, these two
TfcrTecT 3I sels °* r'nfas mav ^e made to cross each other in any direc-

tion,; the small set may belaid upon the large one, or either
of them may be separately removed towards any part of the
glass. This will be sufficient to show, that they have no con-
nection with each other. The phenomena of the motions,
and of the various colours and sizes assumed by these rings,
when different pressures and tiltings of the glasses are used,
will afford some entertainment. With the assistance of the

shadow

pEUSCHEL ON COLOURED RINGS. 131

shadow of the penknife the secondary set belonging to the
rings from the 26-inch lens will be added to the other two
sets; but in tilting the glasses this set will never leave its pri-
mary one, while that from the 50-inch lens maybe made to
go any where across the other two.

V. Of three sets of Rings.

To see three sets of concentric rings at once is attended Three sets of
with some difficulty, hut by the assistance of the methods of ring3-
tilting the glasses, and making use of the multiplied shadows
of a penknife, we may see them very well', when there is a
sufficient illumination of bright daylight.

First Method. A 26 inch double convex lens placed upon lst A ]ens Qrl
three slips of plain glass will give three sets of rings. The three slips of
slips of glass should be nearly 2 tenths of an inch thick, other- &"
wise the different sets will not be sufficiently separated. When
all the glasses are in full contact, the first and second sets
may be seen with a little pressure and a small motion, and, if
circumstances are favourable, the third, which is the faintest,
will also appear. If it cannot be seen, some of the compound
shadows of the penknife must be thrown upon it; for in this
case there will be five shadows visible, several of which will .
fall together, and give different intensity to their mixture.

Second Method. When a single slip of glass, with a 34-inch 2d. Alensand

lens upon it, is placed upon a piece of good looking glass, a sl'P of S,ass

n . , i /• ii-i oa lookhrg

three sets of rings may be seen: the first and third sets are giass,

pretty bright, and will be perceived by only pressing the lens
a little upon the slip of glass; after which it will be easy to find
the second set with the assistance of the proper shadow. In
this case four shadows will be seen ; and when the third sha-
dow is upon the first set, the fourth will be over the second
set and render it visible.

Third Method. When two slips of glass are laid upon a S(i Lens on

• plain' metalline mirror, then a 26-inch lens placed upon the two glassy and
slips will produce three sets of rings ; but it is not very easy me u
to perceive them. By a tilting motion the third set will gene-
rally appear like a small white circle, which at a proper dis-
tance will follow the movement of the first set. As soon as

I ihe first and third t-ets are in view, the third shadow of the peu-

K 2 knife

1-32 IIEttSCHEL ON COLOURED RING*.

knife may be bruught over the first set, by which means the
fourth shadow will come upon the second set, and in this posi-
tion of the apparatus it will become visible.
4th. Lens on Tourtli Method, On a plain metalline mirror lay one slip
foraunc anan- °f o^ass' but w*tn a sina^ piece of wood at duc end under it,
glewith metal, so that it may be kept about one tenth of an inch from the
mirror, and form an inclined plane. A 20-inch lens laid upon
the slip of glass will give three sets of rings. Two of them
will easily be seen; and when the shadow of the penknife is
held between them the third set will also be perceived. There
is but one shadow visible in this arrangement, which is the
third; the first and second shadows being lost in the bright
reflection from the mirror.
5th. A convex Fifth Method. I placed a 6|-inch double convex upon an
cavea^d^hpof ^""icn double concave, and laid both together upon a plain
glass. slip of glass. This arrangement gave three sets of rings. They

may be seen without the assistance of-shadows, by using only
pressure and tilting. The first had a black and the other twd
v had white centres.

VI. Of four sets of Rings.

Four sets of- The difficulty of seeing many sets of rings increases with
rinSs« their number, yet by a proper attention to the directions

that are given four sets of concentric rings may be seen.
1st, Lens on a First Method. Let a slip of glass, with a 26-inch lens
glass forming (^j Up0n j* fce p]aced upon a piece of looking glass. Un-
aa angle With . l to.,. ,, • ,. , t />

a mirror. der one end oi the slip, a small piece ot wood one tenth of

an inch thick must be put, to keep it from touching the
looking glass. This arrangement will give us four sets of
rings. The first, third, and fourth may easily be seen, but
the second set will require some management. Of the three
shadows, which this apparatus gives, -the second and third
must be brought between the first and fourth sets of rings,
in which situation the second set of rings wjjl become visible.
2d. Piano cor.- Second Method. When three slips of glass are laid upon
rex 'ens on a metalline mirror, and a plano-convex lens of about 17

three sii,js Of i , ' .

glass & metal, inches focus is placed with its convex siue upon them, four
sets of rings may be seen ; but this experiment requires a
very bright day, and very clean, highly polished slips of

plain

HEItSCHEL ON COLOURED RINGS. 133

plain glass. Nor can it be successful unless all the forego-
ing- methods of seeing multiplied sets of riugs are become
familiar and easy.

I have seen occasionally, not only four and five, but even 5 or G sets of
six sets of concentric rings, from a very simple an-angement rulSs-
of glasses : they arise from reiterated internal reflections ;
but it will not be necessary to carry this account of seeing
multiplied sets of rings to a greater length.

VII. Of the Size of the Rings.

The diameter of the concentric rings depends upon the Sizeofthe

radius of the curvature of the surfaces between which they nngs*

are formed. Curvatures of a short radius, cretcris paribus,

give smaller rings than those of a longer; but Sir I. Newton

having already treated on this part of the subject at large,

it will not be necessary to enter farther into it.

I should however remark, that, when two curves are con- Inverselyas<the
. . •.• n 1 i 1 ,i -ii angle of con-

cerned, it is the application of them to each other, that will tacU

determine the size of the rings, so that large ones may be v

produced from curvatures of a very short radius. A double

convex lens of 2^-mches focus, for instance, when it is laid

upon a double concave which is but little more in focal length,

gives rings that are larger than those from a lens of ci6 inches

laid upon a plain slip of glass.

VIII. Of Contact.

The size of the rings is considerably affected by pressure. Pressing the

Thev srow larger when the two surfaces that form them are surfaces toSe~
J 5 e , 1 i- • • 1 1 • ther enlarges

pressed closer together, and diminish when the pressure is the rings.

gradually removed. The smallest ring of a set may be in-
creased by this means to double and treble its former diame-
ter ; but as the common or natural pressure of glasses laid
upon any flat or curved surface is occasioned by their weight,
the variations of pressure will not be very considerable,
when they are left to assume their own distance or contact.
To produce that situation, however, which is generally cal-
led contact, it will always be necessary, to give a little mo-
tion backwards and forwards to the incumbent lens or glass,
accompanied with some moderate pressure, after which it
may be left to settle properly by its own weight.

IX.

134 HERSCHEL ON COLOURED RINGS.

IX. Of measuring Rings.

The rin^s dif- ^ maY ^e supposed from what has been said concerning
fault to mea- the kind of contact, which is required for glasses to produce
lute! * . rings, that an attempt to take absolute measures must be
liable to great inaccuracy. This was fully proved to me,
when I wanted to ascertain, in the year 1792, whether a lens
laid upon a metalline surface would give rings of an equal
diameter with those it gave when placed on glass. The
measures differed so much, that I was at first deceived ; but
on proper consideration it appeared, that the Huygenian ob-
ject glass, of 122 feet focus, which I used for the experiment,
could not so easily be brought to the same contact on metal
as on glass ; nor can we ever be well assured, that an equal
distance between the two surfaces in both cases has been ac-
tually obtained. The colour of the central point, as will be
shown hereafter, may serve as a direction; but even that
cannot be easily made equal in both cases. By taking a
sufficient number of measures of any given ring of a set,
when a glass of a sufficient focal length is used, we may
however determine its diameter to about the 25th or 30th
part of its dimension.
But their pro- Relative measures, for ascertaining the proportion of the
portions in the different rings in the same set to each other, may be more
it!?i«Sm«T°ie accurately taken, for in that case the contact with them all

CdSIlj IT J Gel* •*

sured. will remain the same, if we do not disturb the glasses during

the time of measuring.

X. Of the Number of Rings,
Number of When there is a sufficient illumination, many concentric

nnSs« rings in every set will be perceived ; in the primary set we

see generally 8, 9, or 10, very conveniently. By holding
the eye in the most favourable situation I have often counted
near 20, and the number of them is generally lost, when
they grow too narrow and minute to be perceived, so that
we can never be said fairly to have counted them to their
full extent. In the second set I have seen as many as in the
first, and they are full as bright. The third set, when it is
seen by a metalline mirror under two slips, will be brighter
than the second, and almost as bright as the iirst: I have
easily counted 7, 8, aud 9 rings. •

XI.

HERSCIIEL ON COLOURED RINUS, \$$

XI. Of the Effect of Pressure on the Colour of the Rings.

When a double convex object glass of 14 or 15 feet focus Their colours

is laid on a plain slip of glass, the first colours that make their affccted b^

r . pressure*

faintest appearance will be red surrounded by green; the

smallest pressure will turn the centre into green surrounded

by red : an additional pressure will give a red centre again,

and so on till there have been so many successive alterations,

as to give us six or seven times a red centre, after which the

greatest pressure will only produce a very large black one

surrounded by white.

When the rings are seen by transmission, the colours are
In the same manner subject to a gradual alternate change
occasioned by pressure , but when that is carried to its full
extent, the centre of the rings will be a large white spot sur-
rounded by black.

The succession and addition of the other prismatic colours,
after the first or second change, in both cases is extremely
beautiful ; but as the experiment may be so easily made, a
description, which certainly would fall short of an actual view
of these phenomena, will not be necessary.

Wrhen the rings are produced by curves of a very short
radius, and the incumbent lens is in full contact with the slip
of glass, they will be alternately black and white; but by
lessening the contact, I have seen, even with a double convex
lens of no more than two tenths of an inch focus, the centre
of the rings white, red, green, yellow, and black, at pleasure. -
In this case I used an eye-glass of one inch focus; but as it
requires much practice to manage such small glasses, the
experiment may be more conveniently made by placing a
double convex lens of 2 inches focus on a plain slip of £>lass,
and viewing the rings by an eye-glass of 2f inches; then
having first brought the lens into full contact, the rings will
be only black and white, but by gently lifting up or tilting
the lens, the centre of the rings will assume various colours
at pleasure.

XII. Of diluting and concentrating the Colours.

Lifting up or tilting a lens being subject to great uncer- Method of dfc
tainty, a surer way of acting upon the colours of the rings is lutinS or con"

by

~13& HERSCHEL ON COLOURED RINGS,

centrating the by dilution and concentration. After having seen tli at very-
colours. Ml 1111 ft 1 • 1 • <* ,i

small lenses give only black and white when in full contact,
we may gradually take others of a longer focus. With a
double convex lens of four inches the outward rings will be*
gin to assume a faint red colour. With 5, 6, andV, this ap-
pearance will increase; and proceeding with lenses of a larger
focus, when we come to about 16, 18, or 20 inches, green
rings will gradually make their appearance.

This and other colours come on- much sooner if the ceutre
of the lens is not. kept in a black contact, which in these ex-
periments must be attended to.

A lens of 26 inches not only shows black, white, red, and

green rings, but the central black begins already to be diluted

so as to incline to violet, indigo, or blue. With one of 34, the

white about the dark centre begins to be diluted, and shows a

kind of gray inclining to yellow. With 42 and 48, yellow

rings begin to become visible. With 55 and 59, blue rings

show themselves very plainly. With a focal length of 9 and

II feet, orange may be distinguished from the yellow and

indigo from the blue. With 14 feet, some violet becomes

Analysis of the vis]Dle. When the 122-feet Huygenian glass is laid on a
black & white . . ,. s ■ « i , •/ i * ? i i • ;1 '

centre. plain slip, and well settled upon it, the central colour is then

sufficiently diluted, to show that the dark spot, which in smalj
lenses, when concentrated, had the appearance of black, is
now drawn out into violet, indigo, and blue, with a little ad-
mixture of green ; and that the white ring, which used to be
about the central spot, is turned partly green with a sur-
rounding yellow, orange, and red-coloured space or ring; by
which means we seem to have a fair analysis of our former
compound black and white centre.

One of my slips of glass, which is probably a little con<-
cave, gave the rings still larger, when the 122 feet glass was
firmly pressed against it. I used a little side motion at the
same time, and brought the glasses into such contact, that
they adhered sufficiently to* be lifted up together. Witli
this adhesion I perceived a colour surrounding a dark centre^
A light brown which I have never seen in any prismatic spectrum. It is a
kind of light brown, resembling the colour of a certain sort of
Spanish snuff. The 170 feet object-glass showed the same
colour also very clear! v.

XIII.

HERSCHEL ON COLOURED RINGS.

XII I. Of the order of the Colours.

The arrangement of the colours in each compound ring or The most re-
alternation, seen by reflection, is, that the most refrangible frangible rays

. J , \ . , • ■ . ■ • , rt, nearest the

rays are nearest the centre; and the same order takes place centre
when seen by transmission. We have already shown, that,
when a full dilution of the colours was obtaiued, their ar-
rangement was violet, indigo, blue, green, yellow, orange,
and red ; and the same order will hold good, when the co-
lours are gradually concentrated again ; for though some of
them should vanish before others, those that remain will al-
ways be found to agree with the same arrangement.

If the rings should chance to be red and green alternately,
a doubt might arise, which of them is nearest the centre ; but
by the method of dilution, a little pressure, or some small in-
crease of the focal length of the incumbent lens, there will
be introduced an orange tint between them, which will im-
mediately ascertain the order of the colours.

In the second set of rings the same order is still preserved ia all cases,
as in the first ; and the same arrangement takes place in the
third set as well as in the fourth. In all of them the most

refrangible rays produce the smallest rings.

t »

XIV. Of the alternate Colour and Size of the Rings belong-'
ing to the primary and dependent Sets.

When two sets of rings are seen at once, and the colour Alternation of
of the centre of the primary set is black, that of the secon- the depep'Hwt
dary will be white; if the former is white, the latter will be ^j ^J^ ° r
black. The same alternation will take place if the colour, of
the centre of the primary set should be red or orange ; for
then the centre of the secondary one will be green ; or if
the former happens to be green, the latter will be red or
orange. At the same time there will be a similar alternation ,

in the size of the rings ; for the white rings in one set will be
of the diameter of the black in the other ; or the orange
Tings of the former will be of equal magnitude with the
green of the latter.

M lien three sets of rings are to be seen, the second and
third sets will be alike in colour and size, but alternate in
both particulars with the primary set.

Tne

T5S" HERSCHEL ON COLOURED RINGS.

The same thin^ will happen when four sets are visible;
for all the sets that are formed from the primary one will re-
semble each other, but will be alternate in the colour and
dimensions of their rings with those of the primary set.

XV. Of the sudden Change of the Size and Colour of the
Jiings in different Sets,

The size and When two sets of rings are viewed, which are dependent

fin""in0f thG upon eac}l other> the co,our of tneir centres, and of all the
different sets rings in each set, may be made to undergo a sudden change
Sly chanced ^ *^e aPProacn of the shadow of the point of a penknife or
other opaque slender body. To view this phenomenon pro-
perly, let a 1 6-inch double convex lens be laid upon a piece
of looking glass, and when the contact between them has
been made to give the primary set with a black centre, that
of the secondary will be white. To keep the lens in this
contact, a pretty heavy plate of lead with a circular hole in
it of nearly the diameter of the lens should be laid upon it.
The margin of the hole must be tapering, that no obstruc-
tion may be made to either the incident or reflected light.
When this is properly arranged, bring the third shadow of
the penknife upon the primary set, which is that towards the
light. The real colours of this and the secondary set will
then be seen to the greatest advantage. When the third
shadow is advanced till it covers the second set, the second
, shadow will at the same time fall upon the first set, and the
colour of the centres, and of all the rings in both sets, will
undergo a sudden transformation from black to white and
white to black.

The alternation of the colour is accompanied with a
change of size, for as the white rings before the change were
of a different diameter from the black ones, these latter,
having now assumed a black colour, will be of a different
size from the former black ones.

When the weight is taken from the lens, the black con-
tact will be changed into some other. In the present expe-
riment it happened, that the primary set got an orange co-
loured centre, and the secondary a green one. The same
way of proceeding with the direction of the shadow being
then pursued, the orange centre was instantly changed to a

green

.— -. Nicholson's fhtfoj. Journal*, Vol. HX.PlJf'b./3q .

fy *■ fig. 2.^

Fiy.3.

/a

IT"

Ify.4-

d

Fy.5.

Jfy.d

IIERSCHEL ON COLOURED RINCS. 1^9

green one, while at the same moment the green centre was,
turned into orange. With a different contact I have had the
primary set with a blue centre and the secondary with a deep
yellow one; and by bringing the second and third shadows
alternately over the primary set, the blue centre was changed
to a yellow, and the yellow centre to a blue one ; and all the
rings of both sets had their share in the transformation of co-
lour and size.

If there are three sets of rings, and the primary set has a
black centre, the other two will have a white one; and when
the lowest shadow is made to fall on the third set, the central
colour of all the three sets will be suddenly changed, the first
from black to white, the other two from white to black.

A full explanation of these changes, which at first sight
have the appearance of a magical delusion, will be found in a
future article.

XVI. Of the Course of the Rays by which different Sets
of Rings are seen.

In order to determine the course of the rays, which give Determination

the rings both by reflection and bv transmission, we should °. J!,course
c> " j ine ru. j s.

begin from the place whence the light proceeds that forms
them. In PI. IV, fig. 1 , we have a plano-convex lens laid upon
three slips of glass, under which a metalline mirror is placed.
An incident ray 1, 2, is transmitted, through the first and
and second surface of the lens, and comes to the point of
contact at 3. Here the rings are formed, and are both re-
flected and transmitted : they are reflected from the upper
surface of the first slip, and pass from 3 to the eye at 4:
they are also transmitted through the first slip of glass from
3 to 5 ; and at 5 they are again both reflected and transmit-
ted ; reflected from 5 to 6, and transmitted from 5 to 7 ; from
7 they are reflected to 8, and transmitted to 9; and lastly
they are reflected from 9 to 10. And thus four complete sets
of rings will be seen at 4, 6, 8, and JO.

The most convenient way of viewing the same rings by
transmission is that, which has been mentioned in thesecoud
article of this paper, when light is conveyed upwards by re-
flection. In figure 2, consisting of the same arrangement
of glasses as before, the light by which the rings are to be

seen

140 HERSCrtfcL ON COLOURED RlNf.S.

seen comes either from 1, 2, or 3, or from all these places to-
gether, and being reflected at 4, 5, and 6, rises up by trans*
mission to the point of contact at 7, where the rings are
formed. Here they are both transmitted tip to the eye at 8,
and reflected down to 9 ; from 9 they are reflected up to 10
and transmitted down to 11 ; from 11 they are reflected to 1 J
and transmitted to 13 ; and lastly, from 13 they are reflected
to 14 ; so, that again four sets of rings will be seen at 8, 10,
12, and 14.

This being a theoretical way of conceiving how the rays
of light may produce the effects, it will be required to show
by experiments, that this is the actual progress of the rays,
and that all the sets of rings we perceive are really reflected
or transmitted in the manner that has been pointed out ;
but as we have so many reflections and transmissions. be-
fore us, it will be necessary to confine these expressions to
one particular signification when they are applied to a set of

and transmit
tech

What is meant When the centre of the rings is seen at the point of con-
by reflected tact, it is a primary set; and 1 call it reflected, when the
rays which come to that point and form the rings undergo
an immediate reflection. But I call it transmitted, when
the rays, after having formed the rings about the point of
contact, are immediately transmitted.

Thus in figure 3 and 4 the rays a b c, d e f, give reflected
sets of rings; and the rays g h i, k I m, in figure 5 and 6,
give transmitted sets.

In this denomination, no account is taken of the course of
the rays before they come to a, (J, g, k; nor of what be-
comes of them after their arrival at c, f9 i, m : they may
either come to those places or go from them by one or more
transmissions or reflections, as the case may require ; but our
denomination will relate only to their course immediately af-
ter the formation of the rings between the glasses.

The secondary and other dependent sets will also be called
reflected or transmitted by the same definition : and as a set
of these rings formed originally by reflection may come to
the eye by one or more subsequent transmissions; or being
formed by transmission, may at least be seen by a reflection
from some interposed surface, these subsequent transmissions

HERSCIIEL ON COLOURED RINGS. 141

or reflections are .to be regarded only as convenient ways to
get a good sight of them.

With this definition in view, and with the .assistance of a
principle which has already been proved by experiments, we
may explain some very intricate phenomena; and the satis-
factory manner of accounting for them will establish the
truth of the theory relating to the course of rays that has
been described.

The principal to which I refer is, that, when the pressure
is such as to give a black centre to a set of rings seen by re-
flection, the centre of the same set, with the same pressure
of the glasses, seen by transmission will be white*.

I have only mentioned black and, white, but any other al-
ternate colours, which the ring3 or centres of the two set*
may assume, are included in the same predicament.

XVII. Why two connected Sets of Rings are of alternate
Colours.,

It has already been shown, when two sets of rings are Whytwocou-

seen, that their colours are alternate, and that the approach nected sets ar<*
3 ' 'r of alternate co»

of the shadow of a penknife will cause a sudden change of lours.

them to take place. I shall now prove, that this is a very ob-
vious consequence of the course of rays that has been propo-
sed. Let figure 7 and 8 represent the arrangement given in
a preceding article, where a 1 6-inch lens was laid upon a
looking glass, and gave two sets of rings with centres of dif-
ferent colours : but let figure 7 give them by one set of rays,
and figure 8 by another. Then, if the incident rays come in
the direction which is represented in figure 7» it is evident
that we see the primary set with its centre at 2 by reflection,
and the secondary one at 4 by transmission. Hence it fol-
lows, in consequence of the admitted principle, that if the
| contact is such as to give us the primary set with a black cen-
tre, the secondary set must have a white one ; and thus the
reason of the alternation is explained.

But if the rays come as represented in figure 8, we see the
primary set by transmission, and the secondary one by reflec-
tion ; therefore, with an equal pressure of the glasses, the

* See Article XI, of this Paper, p. 1S5.

primary

142 JlETtSClIEL ON COLOURED RINGS.

primary centre must now be white, and the secondary one
black.

Without being well acquainted with this double course of
rays, we shall be liable to frequent mistakes in our estimation
of the colour of the centres of two sets of fittgs ; for by a cer-
tain position of the Itgnt, or of the eye, we may see one set
by one light, and the other set by the other.

XVIII. Of the Cause of the sudden Change of Colours.

Cause of the Having thus accounted for the alternation of the central

sudden change co]ourS) we mav easily conceive, that the interposition of
of colour. . ,

the penknife must have an instantaneous effect upon them.

When it stops the rays of figure 7, which will happen when
its second shadow falls upon the primary set, the rings will
then be seen by the rays I, 2, 3, 4, and 1, c2, 3, 5, 6, of figure
8. When it stops the rays of figure 8, which must happen
when the third shadow falls upon the primary set, we then
see both sets by the rays 1, 2, 3, and 1, 2, 4, 5, of figure 7.
When the penknife is quite removed, both sets of rays will
come to the point of contact, and in some respects interfere
with each other ; but the strongest of the two, which is gene-
rally the direct light of figure 7, will prevail. This affords a
complete explanation of all the observed phenomena: by the
rays of figure 7 the centres will be black and white ; by those
of figure 8 they will be white and black ; and by both we
shall not see the first set so well as when the third shadow, be-
ing upon it, has taken away the rays of figure 8: indeed we
can hardly see the secondary set at all, till the shadow of the
penknife has covered either the rays of figure 7 or of figure 8.
Both thecen- As soon as we are a little practised m the management of
trcs and rings t]]e rdySf by knowing their course, we may change the colour
^partially, so gradually as to have half the centre white, while the other
half shall still remain black ; and the same may be done with
green and orange, or blue and yellow centres. The rings of
Loth sets will also participate in the gradual change; and
thus what has been said of the course of rays in the l6th ar-
ticle will again be confirmed.

To he concluded in our next,

VIII.

SPECIFIC GRAVITY OF LIGHT, \^§

VIII.

A Method of finding the specific Gravity of Light from Ana*
logy; and the undulalory St/stem defended by an Expert*
mod on inflected Light. In a Letter from Mr* Richard
Winter.

To Mr. NICHOLSON.

Dear Sir, Wliithy, Jan. 8th, 1S03.

JL HE undulatory system of light had until within very Undulatory
lately become exploded by the extraordinary abilities of New- system of UgUt
ton, and his great exertions in favour of the emanative sys- a^|n to'c^iff*
tern ; bat no name, however great, should prevent inquiry attention,
after truth and extension of science, so naturally allied to
the civilization and happiness of mankind. It is, I believe,
generally allowed, that few discoveries have been made by
pursuing a beaten path ; it is on this account that so few im»
provements have been made in the theory of light since the
time of Sir Isaac Newton. Dr. Young's experiments, and
reasoning from facts, in favour of the undulatory motion of
light, are deserving of impartial attention.

The great influence of light on vegetables and animals is Light has g*aai
ascertained, from the want of colour in both when deprived influence on
thereof; and the vigour, odour, and density of tropical anhnals-
plants, and the ferocity of animals indigenous to those cli-e
mates. Its consequences in the arts and manufactures are ln arts a^j ma^
very considerable, in its various combinations with the ele- nufactures 5
mentary bodies. Its effect also upon man is acknowledged on man*
and felt by all nations, so as to contribute a principal cha->
racteristic (viz. that of colour).

The physical phenomena arising therefrom display a wide and t «

field for the investigation of the natural philosopher, in the phenomena,
production and change of colours — the formation of the rain-
bow, parhelia, haloes, &c.

It has baffled the ingenuity of man to determine its den^ It:} jcasjty Bo6
sity by mechanical means. Michell attempted to find its e«y fe.aiOTN

momentum

] .|.]j SPECIFIC CR.WITY OF M(.I1T

tain mechanl- momentum upon a balance, but the transmission through

fa y* different glasses will vary, as the lenses may happen either to

differ in density or transparency ; and consequently will give
different results. You also advanced (Introduction to Na-
tural Philosophy) some ingenious arguments to decide ife
amazing subtlety, founded upon undoubted principles.

Mav perhaps ^^g following analogy will appear perhaps hypothetical ;

analogically, however, such as it is I will submit it to the candid and dis-
criminating', to determine whether the conclusions are sub-
stantial or premature.

Undulations of The resistance of fluids is as their densities reciprocally;

their gravities, therefore it may be presumed, that the undulations of diffe-
rent mediums will, bear. the baine proportion to one another,
as their specific gravities.

Velocity of It has been demonstrated by the accurate observations and

those of light, ^coyeries 0f £>r. Bradley on the aberration of light, that
this medium is conveyed from the sun to the earth, or in
other words, an undulation of light reaches the earth from
the sun, in the space of 8' 7*5" of time. Taking the mean
apparent diameter of the sun at 32' 1*5 ''» and his mean ho-
rizontal parallax at 8'72", as determined by Dr. Maskelyne,
and the semidiameter of the earth at 3964 miles, we shall
find the sun's real diameter to be 873,489 miles, and his dis-
tance from the earth equal to 93,334,047 miles: therefore

the velocity of lieht will be determined thus, J~>J 1 '■ ~

J b ' 8' 7-5"

191,434 miles in one second of time, or 1,010,771,520
feet.
Undulations of* According to Hales (Statics, Vol. TI, p. 331) the velo-
*** ared*1 * c't*v °^ modulating air is to the velocity of undulating water
as 8C5 to 1, or as their specific gravities. The motion of
sound is found to be 1130 feet in one second (Young's Syl-
labus of a Course of Lectures, 1802): then, as the velocity
of sound is to the velocity of light, so is the specific gravity
Hence Kgfat of air to the specific gravity of light, according to the fol-

4 B • ;m>s 1010rT71520

lighter than lowing formula ; — : — = 894,583 times lighter than at-
mospheric air; or it will require 1553 cubic feet of light to
weigh one grain. If we compare them with water, taken as

unity

air

SPECIFIC GRAVITY OF LIGHT. 145

wnity, we shall find them expressed as follows at a mean
temperature.

SPECIFIC GRAVITIES.

Water 1-00000000000

Air 0*00120000000

Light o-oooooooooi3

If this be the real density of light, it will appear, that all Hence incapa-
former attempts to appreciate its specific gravity by meeha- J*1^.0* vjjf
meal means must have been fruitless, as the quantity thrown rectly.
by a lens, however large, upon a balance of the most de.i-
cate-construction, must be exceedingly minute; yet it may
have very considerable effects when exerted upon the body
of the planets. May not the diurnal motion of the planets
be the effect of its momentum?

It appears to me, that the experiment on inflected light, Inflection^
mentioned in Newton's optics, performed by passing the ^faine(j b/un-
light through an aperture of a window shutter into a dark- duiation than
ened room, is much better explained, by allowing an undu-
latory than a radiating motion of light.

It is the nature of all fluids to undulate in circular arcs
when moved by any impulse.

Let a represent an aperture into a darkened room, equal Phenomena of

• ^ c • i • j* 2. j * flight admitted

to TV part ot an inch in diameter, 6, e, a, e, j, waves ot t|jrou(rh a

light, moving in succession against the solid object g h, small aperture.

which we will suppose the side of a house : here the light,

meeting with an opake substance, will be reflected every

where, except at the aperture «, which will then become

the centre of motion. The undulating light, having passed

the aperture, will dilate in the concentric arcs 1, 2, 3, 4, &c,

till they arrive at i, on the opposite side of the room; and

the greater the distance between a and i, the greater will be

the diameter of the shadow of the aperture; all obstacles

placed in this lucid stream will have their shadows augmented

in diameter, when received upon the wall, in proportion to

their distance therefrom.

If the attraction of the sides of the aperture and window Not owing to
shutter was the cause of this enlargement of the shadow, j*f ."J^J t-the
the obstacle^ when interposed in the lucid stream within the sides of the
room, would also attract the light, and the diameter of its al)erlure«

Vol. XIX— Feb. 1808. L shadow,

146 ACCIDENT FKOM THE DECOMPOSITION OF POTASH.

shadow, instead of being augmented (as it really appears to
be), would be diminished.

I am very respectfully,

Your obedient servant,

RICHARD WINTER.

It gives me great pleasure to observe, that you have under-
taken to publish an Encyclopedia upon a limited scale. It
will be peculiarly adapted to the interest of the artizan, the
mechanic, the manufacturer, and to the most numerous class
of society.

There is one article which would be useful to your coun-
try readers, I mean a Monthly Meteorological Register in-
serted in the Journal, of the Barometer, Thermometer,
Winds, &c. at London, in order to enable them to compare
them with observations made in the country; perhaps this
may be inconsistent with your plan, which is generally ap-
proved.

As it is my wish to gratify all my readers, in whatever
tends to promote the interests of science, I shall take mea-
sures to comply with the request of my correspondent, by
inserting, as soon as conveniently can be done, a meteorolo-
gical register, from a hand that may be relied on with confi-
dence for its accuracy. W. N.

IX.

Account of an Accident from the sudden Deflagration of the
Base of Potash. In a Letter from a Correspondent.

SLR, To Mr- NICHOLSON,

Caution -OlS the late brilliant discoveries by Mr. Davy, of the de-

ugainst acci-
dents in de-

composition of the fixed alkalis, will probably induce many
composing the to repeat his experiments, I take the liberty of suggesting
alkahs. to them, through the medium of your Journal, the caution

of using glasses to defend the eyes during the operation. The
flat glasses, commonly called goggles, are best adapted to
the purpose.

For want of this precaution, I yesterday met with an ac-
cident, from which I have suffered much pain, and might
even have been totally deprived of sight by it. A consider-
able

ON THE DECOMPOSITION OP THE FIXED ALKALIS. ] 47

able quantity of potash being decomposed in the galvanic Potash being

circle, a sudden deflagration of the metallary base ensued, ^^J^/

by which several particles of the caustic alkali were thrown deuly deftagra-
. , ted,

into my eyes. : .

. ,., -ii i ,i 1 and several

To prevent the like accident happening to others, who partictes

mav be ensued in similar experiments, is my motive for thrown into

n , . ,T~ 1 • • , • ■ tne operator'*

sending you this. Vv nether it is worth your notice or not, eyes#

you will judge.

I remain, blrl,

Your obedient servant,
Tunbridge, Jan. 22, 1808. PHILOMMATOS.

P. S. I lose no time in making the communication, but
my eyes are still so weak, I can scarcely see to write.

X.

Correction of some Misstatements in the Account of Mr. Davfs
Decomposition of the fixed Alkalis. In a Letter from a
Correspondent.

To Mr. NICHOLSON.

SIR* London, Jan. 24, 180S.

JL HE extensive circulation of your excellent Journal both Misstatements
at home and abroad makes it more desirable, that it should in the account
not be the means of propagating any incorrect statements of °>0^Jfon^"n"e
scientific facts; and such statements are given in the account fixed alkalis.
of Mr. Davy's important discovery of the decomposition of
the fixed alkalis.

I was present at the reading of his lecture. I paid the
greatest attention to it. I feel that your well known love of
philosophical justice will induce you, to give a place in your
publication to what I am convinced were the real accounts
of the author.

It is stated in your Journal, that the basis of potash is vo- Basis of potash

latile at 100°. Mr. Davy's account was, that it is volatile ™jatile a h"le

.... below a red

at a heat a little below redness. It is likewise said, that the heat.

amalgam of the basis of potash and quicksilver, when ap- Its amalgam
plied in the circle of a galvanic battery, dissolved iron, sil- dlssolve* nie"
ver, gold, and platina. Mr. Davy merely mentioned, that
it dissolved these metals ; he said nothing, that \ can recol-
lect, of the galvanic battery.

L 2 Glass,

148 IMPROVEMENT IN THE GALVANIC APPARATUS.

It decomposes Glass, it is said in your Journal, is dissolved by the basis

f aSS b- • a °^ Potasn m tne same manner as tlie metals. The real
with its aUcafi statement with regard to glass was, that the basis of potash

into an oxide decomposed it by combining w'.th its alkali, and bv forming
with less oxt- , .. c , , .. . ,'• .

ireri than pot- a rccl oxlde ot a less degree ot oxygenation than potash,

ash. which oxide was likewise procured. by other means.

Spec. grav. of It is stated, that the specific gravity of the basis of soda

&tdabo-9 of is to that of water as 7 10 10, Mr* Ddyy sald' as 9 to 10,

I am, Sir, with great respect,

Your obedient humble servant,

A CHEMIST.

XI.

An Improvement in the Galvanic Trough, to prevent the Ce-
ment from being melted, when the Action is very powerful.
Communicated by a Correspondent.

SIR? To Mr. NICHOLSON.

Cement of tne JL HE superiority of galvanic batteries constructed on the
trough hable principle of Volta's couromie des tasses, as recommended
to be melted bv Mr. Wilkinson, is, I believe, fully established. One in-
evolveV at convenience however attends it: the action of the acid on
the zinc plates being greatly increased, the quantity of ca-
loric evolved is fo considerable, as frequently to melt the ce-
ment with which the wooden partitions of the troughs are
This may be covered. To remedy this inconvenience, I have had recourse

remedied by t |agg petitions, and rind them answer mv expectations

making the .

partitions of completely. Tj; is better to make them so much larger than

glasi. t^e 1Tieta.llic plates, as to leave a space of about half an inch

(it should not I think be less) between the sides and bottom
of the trough, and metallic plates. Common crown glass
is perfectly adapted to the purpose: its thickness, of course,
must be proportioned to the size required ; and the top edge

This battcrv should be around smooth. A batterv constructed on this

, .■ , o * . .

to^r-aYin en I>lan may be excited to great intensity, without injuring the
sity. cement at all.

I have the honour to be, Sir,

Your obedient servant, J. G. C.
TunbridgCyJan.Zl, 1808.

XII

ON THE FIRE-DAMP OF COAL MINES. 149

XI r.

Experiments on the Fire-damp of Coal Mines, by William
Henry, M. D. ; including a Communication on the Sub-
ject from Thomas Thomson, M. D. F.R.S.E. Com-
municated by Dr. Henry,

BOUT the close of 1S06, I received, from the Rev. History of the
William Turner of Newcastle on Tyne, two bladders filled ^ctedTexpt
with the fire-damp, which had been procured from a coal riment.
mine in the neighbourhood of that town. It was caught by
luting a common funnel over the month of a blower *, and
tying a compressed bladder to the pipe of the funnel, after
the gas had issued from it for some time. My experiments
were made on the gas, about seveu days after its being first
collected. At that time, the bladders were perfectly dry, and
bhowed no signs of putrefaction.

The general results of these experiments (as stated in a General re-
memoir which was read in January 1807> before the Medi-
cal Society of Edinburgh) are the following. The gas was
found, by the test of nitric oxide, used in Mr. Dalton's me-
thod f, to contain about 4 its bulk of common air. It had
a disagreeable smell. When set on fire as it issued from the
orifice of a small pipe, it burned with a dark blue flame;
and a long conical glass vessel, held over the flame, was soon
bedewed with moisture. Mixed with common air, it did not
detonate on the approach of a lighted taper, at least in any
proportion that was tried. The utmost effect was a deep
blue flame, which spread quickly through the vessel, but
was not accompanied with any noise. With oxigen gas,
however, it exploded, and gave a loud report. On agitation
with limewater it lost about -V of its bulk. The nicest tests
did not discover any admixture of sulphuretted hidrogen.
One hundred parts by measure appeared, therefore, to con-
sist of

* B'.o'.cers are holes or crevices in the coal or in the accompanying
strata, from which the tire-damp issues, sometime* with considerable
force.

f Phil. Journ. XVI, 247; or I-tenry's Epitome, chap xii,vsect. 2.

63*34 '

150 ON THE FIRE^I>A*lt> OF COAL MINES.

Component ()3'34 atmospherical air

i)arls* 1 -66 carbonic acid

35* inflammable gas

100- 0

Thcinflam.gas The nature of the inflammable gas was next ascertained
hWro'en r * ^y detonation with oxigen gas. Reducing the results to a
general average, and excluding the common air, the really
inflammable part of the gas required for combustion about
twice its bulk of oxigen; and gave its own volume of car-
bonic acid. Hence the inflammable portion of the gas was
carburetted hidrogen. From the experiments of Mr. Dal ton
on the gas from stagnant water, and my own obtained by
distilling pit-coal*, the fire-damp appears to differ very lit-
tle from both those gasses.
Fire-damp less It was desirable, however, to repeat the analysis of fire-
examined by** ^amp, *ess adulterated with common air ; and for this pur-
Dr. Thomson, pose a quantity was collected (as it issued through water on
the floor of the mine) in an inverted bottle, which was well
corked and tied over with bladder. Happening to pass
through Newcastle last spring, I carried this gas with me to
Edinburgh ; and, having no opportunity of making experi-
ments upon it there, my friend Dr. Thomson was so good
as to undertake its analysis, and to furnish me with the fol-
lowing results.
Detail of the From the action of nitrous gas and of lime-water, the gas
andTesul"5 aPPtared by Dr. Thomson's experiments, to contain, in 100
measures,

63 inflammable gas

6 *5 oxigen
Z5'5 azote

5* carbonic acid

100-0

* The gas obtained by the destructive distillation of coal I have
found to contain a variable proportion of sulphuretted hidrogen, and to
differ somewhat from the composition which I have stated in the 11th
vol. of this Journal. The correction of those results 1 reserve for ano-
ther occasion.

The

■

H
5fi

5

ON THE FTRE-DAMP OF COAL MINES.

151

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ON THE FIRE-DAMP OF COAL-MINES.

Over

Over

water.

mercury.

260-4

246-

98*4

90-6

It appears, therefore, that, when the gas was entirely con-
sumed, 12'6 measures of the really inflammable part gave
11*5 measures of carbonic acid, and required for saturation
about 132 measures of oxigen. The average results are the
followiug, excluding the first experiment in which the com-
bustion was far from being perfect.

Measures of oxigen required for saturating

100 measures of fire-damp

Measures of carbonic acid produced '•

The second column contains the average results of two ex-
periments, which Dr. Thomson made over mercury; but
on these he places less reliance than on the foregoing series.
The general issue of his experiments agrees with that of
mine ; and the difference is chiefly in the quantity of oxigen
consumed by the combustion of the fire-damp, which ap-
peared to me not to exceed twice its volume.
The fire-damp I know not whether the result of the foregoing experi-
is not produced ments will be considered as" affording any insight into the
posed pyrites nature °f tne process, by which the fire-damp is generated
nor from water in coal mines. The entire absence of sulphuretted hidro-
coaT^butpro- ^en 8as snowsJ that it is not the immediate product of the
bably from decomposition of water by beds of pyrites ; for in that case,
by the heat o/ tne evolved hidrogen would undoubtedly have dissolved a
pyrites. portion of sulphur. Neither can it arise from the decom-

position of water by coal ; for, besides that coal has no ac-
tion on water at a moderate temperature, this origin is con-
tradicted by the smallness of the proportion of carbonic
acid which is present in the fire-damp. The most probable
supposition is, perhaps, that it is disengaged from coal by
a kind of natural distillation. The heat required for this
purpose may be communicated by contiguous beds of py-
rites ; and may be excited in them by the occasional influx
of water. In confirmation of this opinion it may be ob-
served, that the fire-damp is generated most abundantly af-
ter long and heavy rains. The freedom, also, of some coal
mines fiom this destructive gas, indicates the operation of a
partial cause.

It

OK THE PHOSPHORESCENCE OF BODIES. 153

ft is to be regretted, that the analysis of the lire-damp affords Hence the
no encouragement to expect, that it can ever be destroyed o" opposing
in coal mines by any chemical process, as has lately been the destructivt
proposed. The only feasible method of preventing the J^yJ^J^
dreadful consequences of its combustion is, to enforce the tilaiu weU.
steady execution of a well planned system of ventilation,
not only in the part of the mine actually in work, but in the
old workings or waste. Every accident which has happened
may, I have been informed, be traced either to an errour in
the method of ventilation, or to neglect of its enforcement.
The most important object, therefore, appears to be, the
improvement of the mode of ventilating coal mines ; and
especially the superseding, by proper mechanical contriv-
ances, the necessity of those attentions which are at pre-
sent required on the part of the workmen. The peculiar
expediency of changing the air of a mine, after an accident
tal explosion, before venturing into it, is apparent from the
foregoing experiments, which show, that, after every such
combustion, a large quantity of that gas must have been,
generated, which is known to miners under the name of
choak damp.

Manchester, Jan. 10, 1808*

XIII.

On the Phosphorescence of Bodies, from the Action of the
Electric Explosion. In a Letter from Mr. William
Skrimshire, Jun. to Mr. John Cuthbertson.

I

Dear Sir, Wishech, Jan. 5, 180S.

Have lately resumed my Electrical Experiments, and Continuation

having gone through the inflammables, as also the metal's, °f electrical*

. . . . penments.

metallic ores, and oxides, I take the liberty of sending

them to you. Respecting the phosphoric appearance of bo-
dies, these few experiments are no otherwise interesting,
than as forming additional links in the chain of facts, which
I have formerly stated, and which it is my intention to ex-
tend throughout the animal and vegetable kingdoms. But

as

]j4j OIi THE PHOSPHORESCENCE OF BODIES*

as they discover to us a whole class of bodies devoid of the
least phoxphorescency, after exposure to electric light, they
may be deemed of some importance, especially as being one
step towards leading us to a theory of this phenomenon. I
trust you will be kind enough to send them to Mr. Nichol-
son, to be inserted in his extremely useful Journal.

Combustibles.

Habitudes of Sulphur. 1st, Roll brimstone gives no spark, and 'm

bodies as to the scarcely at all luminous bv the shock. 2d, Flowers of sulphur
electric spark . , , . . l

and the pro- are not phosphoric. 3a, A native specimen pure gave no

spark, and was very slightly luminous by the shock. 4th,

A native specimen mixed with carbonate of lime gave no

spark, but was more luminous than the preceding specimens.

Phosphorus inflames both by the spark and shock.

Charcoal. Some kinds afford very good sparks, are phos-
phorescent upon the surface, and when the rods rest upon
them the dust is dispersed by the explosion, in the forms of
a luminous cloud. But other pieces, which were tried, did
not become phosphoric by exposure to the electric light*

Coke gives a good spark, but is not luminous by the shock*

Cannel coal and common Sunderland coal give sparks
beautifully variegated in minute spangles radiated upon its
surface, but they are not phosphoric. Welsh coal gives
similar sparks, but not so beautiful as the above; and is not
luminous by the shock.

Peat, hard and dry, affords a very good 9park, but is
scarcely luminous.

Soft, porous, very light peat, termed in this neighbour-
hood Ramsay turf, is not luminous except in the track of the
discharge, and even then it is extremely evanescent.

Charred peat affords a very good spark, and is slightly
luminous.

Bitumen, hard and brittle, of a dark brown colour, from
Derbyshire, gives no sparks* but the fluid spreads uniformly
and silently over its whole surface, to pass from the conduce
tor to the knob of the discharger held above it, with an ap-
pearance similar to the electric light in an exhausted receiver.
It is luminous by the shock, as is also the elastic bitumen
from the same country.

Jet

duction of
phosphores-
cence.

Sulphur.

Phosphorus.

Charcoal.

Coke.
Cannel coal.

Peat.

JBHumeri.

ON THE PHOSPHORESCENCE OF BODIES. \o5

Jet and asphaltum, instead of a spark, afford the same ap- Jet. Asphal-
pearance of electric light as bitumen does; but they are not
luminous by the explosion.

Amber gives no spark, but is phosphorescent, especially Amber.
that kind termed fat amber.

Plumbago gives good sparks, and is not phosphoric; but Plumbago.
when mixed with clay, and manufactured into crucibles, it
affords good sparks, which are flame-coloured and purple
upon the surface, and becomes luminous when the shock is
taken above its surface.

Metals, their Ones and Oxides.

As the metals are excellent conductors of electricity, it is
well known that they all afford good sparks; but I have not
been able to perceive any material difference in the colour of
the electric light, from different metals, unless the metal has
been formed into exceeding thin leaves, or otherwise minutely
divided, and the spark be sufficiently strong to produce oxi-
dation.

Not one of the metals is phosphoric by exposure to the The metals are
light of an electric explosion, if its surface be clean and bright. n.ot PhosPh»-

This is the only class of natural bodies, which I have yet
found uniformly to remain dark after exposure to the electric
. light. Some of their ores and oxides, such as the red and yel-
low arsenic, haematites, pyrites which is found in chalk, oxide
of zinc, and oxide of antimony are very slightly luminous;
whilst others, for instance cinnabar, black sulphuret of mer-
cury or ethiops mineral of the shops, mundic, galena,
blend, and the sulphurets of antimony, minium, litharge,
and some other oxides, as readily absorb, and as obstinately
retain within their substance, the electric light to which they
are exposed, as even the metals themselves. In short I have
not met with a single brilliant phosphoric appearance in any
of the metals, ores, or oxides, which I have had the opportu-
nity of subjecting to experiment. These observations en- Tjiese exp^;,
tirely coincide witli the results of experiments on solar phos- ments agree
phori by Beccari, who tried every means that his inventive Bec^r^oTi'so-
genius could suggest, to render the metals phosphoric, but larphosphori.
without success. However it is not surprising, that there
should be a tolerably exact agreement between the observa-
tions

]$Q DECOMPOSITION OFTOTASH BY GALVANISM.

tions of Beccari on solar phor.phori, and those facts, which
are stated in my letters. For as I think there can be no
doubt but the phosphoric appearance of bodies in the dark,
after exposure to the light of the sun, and the phosphores-
cency of those substances that have been exposed to the
light of an electric explosion, proceed from the same cause,
they mtist necessarily be subject to similar laws.

But this subject will claim our attention more particularly
hereafter, when I shall have occasion to speak of the nature
and cause of this phosphoric phenomenon.

I remain, Your's, &c.
WILLIAM SKRIMSH1RE, Ju*.

XIV.

Experiments on the Decomposition of the fixed Alkalis bp
Galvanism. In a Letter from Mr. Charles Sylvester.

To Mr. NICHOLSON.
Dear Sir,

Farther expe- JD>EING on a visit, for a few days, with my friend, Mr.
nments on the J J

decomposition Oakes, Jun. of Derby, we have together made some expe-

o a ka is. riments, in prosecution of the inquiry instituted by Mr.
Davy, relative to the decomposition of the fixed alkalis by
the galvanic influence; the result of whose research has
been recently communicated to the Royal Society.

Potash expos- In the first experiment, we used a pair of troughs, expo-

ed to the action sm„. a surface of 1400 square inches, and placed the potash,
of a surface ot , r . r 1 , , . . „ . . _

1400 inches, which was perfectly pure and white, on a plate of platina ; but

did not moisten it, as is said to have been the casein Mr.Davy's
experiments, the deliquescence of the alkali precluding the
necessity of such precaution. As soon as the platina wire
was brought into contact with the potash, from the opposite
Gas evolved, end of the battery, a considerable quantity of gas was
evolved; arising most probably from a decomposition of the
The alkali water. The alkali, in consequence, assumed a blackish co-
blackened and j0lir which continued to be produced so long as the action
emitted sparks. . > . ' . ° ,,v, .i

was maintained, sparks being frequently emitted ; which- lat-
ter effect has only been observed to take place with charcoal
and the metals. *f

Exposed to the ^ second experiment was made, with the addition of ano-
ther

DECOMPOSITION OF TOTASH BY GALVANISM. \$~(

ther pair of troughs of the same size as the first ; and to re- action of 2800
medy the inconvenience occasioned by the deliquescence of ijqueScence
the potash in the former attempt, a glass tube was employed, prevented by
having a platina wire, coiled into a spiral form, sealed into ^e°3ing in*
one of its ends. The alkali was placed in the tube, sur-
rounded by the spiral wire, and another wire, passing through
a cock which occupied the ,other end of the tube, was, by
sliding freely up and down, made to touch the potash at in-
tervals. The wires being connected with the battery,- and
the alkali slightly moistened, a considerable portion of gas
was evolved, which from time to time exploded by the sparks
produced : the temperature of the mass was materially in- Appearance*
creased, and the black matier, which was deposited on solution a3 bcfore-
of the alkali in water, appeared in greater quantity than be- incased "^
fore. Small portions of this black substance sticking to the Back matter
eud of the wire, on being brought into contact with water, detonated on
suddenly detonated accompanied with a vivid flash ; an ef- water#
feet which was also produced on pouring distilled water into
the tube.
The detonations caused by the black matter coming into Potash does not

contact with water, we ascertained from experiment, could P™**"^ tnis
i iii i • n , i • effect i'1 any

not be produced by potash in any state of dryness; hence it state.

would appear, that some substance has been created during Farther inquiry

the galvanic process, possessed of properties very different P:omised"

from those of the materials employed.

It is our intention however, to resume these experiments
assisted by greater galvanic power, the result of which I shall
transmit to you.

I am, Sir, Your obedient servant,

Derby, 20th Jan. 1808. CHA. SYLVESTER.

SCIENTIFIC NEWS.
Discovery of a complete Mammoth.

JL HE bones that have been discovered in different Mammoth

parts of the northern hemisphere sufficiently prove the ex- Jou,ld in a Per"
. _ . l , • i , fect slute*

istence ot some large animal, or animals, now unknown;

and some writers have even given a particular description of
the quadruped generally called a mammoth, though it would
seem merely from the report of tradition among the uncul-
tivated

15$

SCIENTIFIC NEWS.

discovery.

tivated nations of the north. Lately however one has been
found, not alive indeed, but complete, and in a stare of per-
fect preservation, on the borders of the Frozen ocean. The
following is the account, that has .been received of it from
Petersburg.

Schoumachoff, a Tnngoose chief, about the end of august
1799? when the fishing in the river Lena was over, repaired
according to annual custom to the seaside. Leaving his
family in their huts, he coasted along the shore in quest of
mammoth's tusks, and one day perceived in the midst of a
rock of ice a large shapeless block, not at all resembling the
logs of drift wood eotnrao lily found there. He climbed the
rock, and examined it all round* but could not make out
what it. was. The next year, visiting the same spot, he
found there the carcase of a seacow (tr'rchccus rosmarvs) ;
and observed, not only t^at the mass he had seen the year be-
fore was freer from ire, but that there were two similar pieces
b}' the side of it. These afterward turned out to be the feet
of the mammoth. In 1801, the side of the animal and one
of its tusks appearing very distinctly, he acquainted his wife
and some of his fiends with what he had found. This
however gave them great alarm, for the old men said, that
they had been told by their forefathers a similar monster was
onee before seen in those parts, and the whole family of the
person who discovered it soon became extinct. At this
Schoumachoff was so much alarmed, that he fell sick. On
his recovery however he could not relinquish the expectation
of the profit he might make of the tusks; and directed his
servants to conceal the circumstance carefully, and endea-
vour to keep away all strangers by some pretext or other.
Jt was not till the fifth year, that the ice had melted suffici-
ently to disengage the mammoth, when it fell over on its
sule upon a bank of sand. Schoumachoff then cut off the
tusks, which he bartered for goods to the value of 50 rubles
[ct'll. 5*.] with a Russian merchant. Being satisfied with
Its flesh eaten this, the carcase was left to be devoured by the bears, wolves,

by Hop and a f except what the Yakouts in the neighbourhood

wilo beasts. r , °

cut off to feed their dogs. Previous to this indeed he

Drawing of it. had a rude drawing made of it, which represents it with

pointed ears, very small eyes, horse's hoofs, and a bristly

mane

Tradition of
another.

SCIENTIFIC NEWS. ] jC)

mane extending along the whole of its back. Tn this it has
the appearance of something between a pig and an elephant.

In 1306, Mr. Mich. Adams, of Petersburg, being at Description of
Yakoutsk, fortunately heard of this circumstance, and re- ' '
paired to the spot. When he arrived there, the skeleton,
nearly stripped of its flesh, was entire, one of the forefeet
excepted. The vertebra?, from the head to the os coccygis,
one of the shoulderblades, the pelvis, and the remaining
three extremities, were still held firmly together by the liga-
ments of the joints, and by strips of skin and flesh. The
head was covered with a dry skin. One of the ears, well
preserved, was furnished with a tuft of bristles. These
parts could not avoid receiving some injury during their re-
moval to Petersburg, a distance of 1 1000 wersts [6875 miles] :
the eyes however are preserved, and the pupil of the left eye
is still distinguishable. The tip of the under lip was eaten
away; and the upper being destroyed, the teeth were ex-
posed. The brain, which was still within the cranium, ap-
peared dry. The parts least damaged were one of the fore-
feet and one of the hind: these were still covered with skin,
and had the sole attached to them.

According to theTungoose chief the animal was so corpu-
lent and well fed, that its belly hung down below the knee
joints. Tt was a male, with a long mane, but had neither
tail nor trunk. From the structure of the os coccygis how-
ever, Mr. Adams is persuaded, that it had a short thick tail:
and from the smallness of its snout, and the size of its tusks,
he conceives it could not have been able to feed without the
assistance of a proboscis; but Schoumachoff persisted in the
assertion, that he never saw any appearance of a trunk, and
it does not appear probable, that even his rude draughtsman
would have omitted such a striking feature. The skiu,
three fourths of which are in possession of Mr. Adams, the
part that lay on the ground having been preserved, was of a
deep gray colour, and covered with reddish hair and black
bristles. These, from the dampness of the grouud, had
lost some part of their elasticity. More than a poud [40 lbs.]
weight of them, that had been trodden into the ground by the
bears, was collected, many of them an archine [2 feet 4 in.]
long. What remained of the skin was so heavy, that ten

persons

JgO SCIENTIFIC NEWS.

persons found great difficulty in carrying it to the seaside, in
Its dimensions, order to stretch it on logs of wood. The head weighs llf
pouds [46olbs.]; the two horns, each of which is lj toise
[9~ feet] long, weigh 10 pouds [400 lbs.] ; and the entire ani-
mal measured 4f archines [lOf feet] high, by 7 [l6§- feet]
long. Mr. Adams has seen tusks of the mammoth so curved
as to form three fourths of a circle; and one at Yakoutsk
2 J toises' [15 feet 9 in.] long, an archine [2 feet 4 in.] thick
near the root, and weighing 7 pouds [280 lbs.]. They are
* curved in the direction opposite to those of the elephant,
bending toward the body of the animal ; and th« point is al-
ways more or less worn on the outside, so that the right tusk
is easily distinguishable from the left. He adds, that he
Amber. found a great quantity of amber on the shores.

We understand he wishes to dispose of the skeleton,and means
to employ the money in a journey toward the north pole, and
particularly in visiting what is called the island of Ljaehow,
or Sichow, which, from the information he has received, he
believes to be part of the continent of North America.

St. Thomas's and Guys Hospitals.

The Spring Course of Lectures at these adjoining Hos-
pitals, will commence the beginning of February: viz. at
St. Thomas's,

Anatomy and the Operations of Surgery, by Mr. Clinea
and Mr. Cooper.

Principles and Practice of Surgery, by Mr. Cooper.
Guy%

Practice of Medicine, by Dr. Babington and Dr. Curry.

Chemistry, by Dr. Babington, Dr. Marcet, and Mr. Allen.

Experimental Philosophy, by Mr. Allen.

Theory of Medicine, and Materia Medica, by Dr. Curry
and Dr. Cholmeley.

Midwifery, and Diseases of Women and Children, by
Dr. Haigl ton.

Physiology, or Laws of the Animal (Economy, by Dr.
Haighton.

Structure and Diseases of the Teeth, by Mr. Fox.

JV. B. These several Lectures are so arranged, that no two
of them interfere in the hours of attendance ; and the whole
are calculated to form a Complete Course of Medical and
Chirurgical Instructions. — Terms and other Particulars may
be learnt from Mr. Stocker, Apothecary to Guy's Hospital.

The communications from J. Gougk} Esq., Dr. Gibbcs, and
N. It. 1.. will be given in our next.

A

JOURNAL

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

MARCH, 1908.

ARTICLE I.

Remarks on Torpidity in Animals, in two Letters from John
Gough, Esq.

SIR, Middleshaw, 16 Jan. 1808.

OU have given, in your XVIIIth volume, page 254, Mr. du Pont's
an excellent memoir by Mr. du Pont de Nemours, on a kind ^moir valua"
of death, that may be presumed to be only apparent. This
ingenious philosopher suggests several practical observations
which merit the attention both of the benevolent and the
curious, because they promise to promote the interests of
humanity as well as of science. This writer, however,
adopts one opinion, which perhaps is supported by the au-
thority of antiquity, rather than facts and the known habits
of animals.

Mr. du Pont agrees in opinion, perhaps with the majority The prevaii}n„
of naturalists, respecting the nature of torpidity ; for he re- explanation of
fers it, partly to the benumbing effects of the cold which %f*** 8Ul"
prevails in winter; and partly to a high degree of corpu-
lence, which is generally contracted in autumn, from an un-
restrained indulgence in the abundance and delicacies of that
season. He moreover supposes, that animals do not submit
to this long suspension of the vital functions in obedience to

Vol, XIX— March, 1809. M the

162 ON TORPIDITY IN ANIMALS.

the dictates of necessity; on the contrary, he imagines them

to court a lethargic habit, in consequence of certain pleasing

sensations, which are known to precede the first moments of

sleep.

Objections to The preceding hypothesis is commonly supposed to assign
the preceding .« *",•.", . »■ , , • «• i ,

hypothesis. the true causes ot torpidity; but we doctrine is liable to

certain objections. I will state these in the first place, and
afterwards endeavour to substantiate them by facts, which are
new, or but imperfectly understood. My objections are
contained in the four" following propositions.
Objection 1st. First, Animals do not submit to torpidity upon choice, but
from necessity; and when cold happens to be the immediate
cause, they fly from it, if possible.
Objection 2d. Second, Certain animals apparently support a voluntary
suspension of their functions in summer as well as winter,
when food is withheld from them; this is probably intended
to preserve life by diminishing the action of the system.
Objection Cd. Third, A quadruped noted for its lethargic disposition in
winter may be so far strengthened by a generous diet, as
to retain the full use of its faculties during the time of a se-
vere. frost: from which we may infer, that an emaciated
habit of body is the predisposing cause of torpidity, in op-
position to the common opinion, which assigns this office to
corpulence.
Objection 4th. Fourth, The united action of hunger and a low tempera-
ture has produced a kind of apparent death in a human
being, who was restored to life by stimulating remedies, af-
ter laying several days without sense and motion.
Thefirstobj?c- The hearth cricket (gryllus domesticusj affords a proof of
fie^b^the11 the tirst ob.iection- Those who have attended to the man-
hearth cricket, ners of this familiar insect will know, that it passes the hot-
test part of summer in sunny situations, concealed in the
crevices of walls and heaps of rubbish. It quits its summer
abode about the end of August, and fixes its residence by.
the fireside of the kitchen or cottage, where it multiplies its
species, and is as merry at Christmas as other insects are in
the Dog-days. Thus do the comforts of a warm hearth af-
ford the cricket a safe refuge, not from death, but from
temporary torpidity; which it can support for a long time,
when deprived by accident of artificial warmth. I came to

the

ON TORPIDITY IN ANIMALS.

163

the knowledge of this fact, by planting a colony of these in-
sects in a kitchen, where a constant fire is kept through the
summer, but which la discontinued from November to June,
with the exception of a day once in six or eight weeks. The
crickets were brought from a distance, and let go in this
room in the beginning of September 1806; here they in-
creased considerably in the course of two months, but were
not heard or seen after the fire was removed. Their disap-
pearance led me to conclude, that the cold had killed them;
but in this I was mistaken : for a brisk fire being kept up
for a whole day in the winter, the warmth of it invited my
colony from their hiding-place, but not before the evening;
after which they continued to skip about and chirp the
greater part of the following day, when they again disap-
peared, being compelled by the returning cold to take re-
fuge in their former retreats. They left the chimney corner
on the 28th of May, 1807, after a fit of very hot weather,
and revisited their winter residence on the 31st of August.
Here they spent the autumn merely, and lie torpid at pre-
sent in the crevices of the chimney, with the exception of
those days, on which they are recalled to a temporary exist-
ence by the comforts of a fire.

Crickets are commonly supposed to be exempted by na-
ture from the hardships of torpidity; but the preceding nar-
rative proves the exemption to be conditional in these in- .
sects; and those who take the liberty to argue from analogy
will feel an inclination, to attribute the same accommodating
faculty to other animals, some of which are nearly connect-
ed with the welfare of society. In reality, the supposition Sheep can live
is strongly favoured by facts : for we have frequent instances sno^Un ^
in this part of the nation, of sheep living three or four
weeks under drifts of snow, where they can procure little or
no food ; and a ewe was recovered alive from a drift at En-
nerdale in Cumberland, on Christmas-day last, after re-
maining under it five weeks in a space not exceeding one
yard in diameter. If the same or any other sheep were con-
fined half the time in a moderately warm room, with but
one square yard of grass, no doubt could be entertained
respecting the event of the experiment.

Much has been said respecting the torpidity of those birds a. remark on
M 2 which

jg« ON TORPIDITY IN ANIMALS.

birds of pas- which are seen in summer only ; but though the opinion has
saS0, had its advocates as long ago as Pliny, it has never been

proved, and perhaps it never will. For since the cricket
avoids the cold when it can, and the woodcock, as well as
the snipe, retires from the north at the end of autumn with
the same intention ; it is highly probable, that the swallow,
with many more periodical birds, quits this country, and
flies to warmer regions on the approach of winter; while the
bat, the dormouse, and hedgehog, are obliged to abide the
rigours of the season, benumbed by the frost and debilitated
by hunger. But it is time to return from this digression,
and to come to the second objection, the proof of which is
contained in the following experiment.
The second I took several specimens of the garden snail, helix Jtortensis,

°m^ified bv anc* s^ut tnena UP m a perforated wafer box ; which secluded
two kinds of them from food and water, but not from air. A number of
snails, t|ie fefe ZQnar'ia was treated in the same manner; and a few

of this species were put into a bottle, which was corked, to
cut off all communication with the atmosphere, as well as
food and water. Those snails did not live long which were
deprived of air; but the specimens of both species did not
die which were confined in the perforated boxes. On the
contrary they retired into their shell, closing the apertures
of them with thin membranes; here they remained dead to
all appearance, as long as I kept them dry. But this death
was nothing more than apparent; for I restored my prisoners
to life in succession, by dropping them into a glass con-
taining water of the temperature of 70° or 72°: after leav-
ing them four or five hours in this fituation, I constantly
found them alive, and sticking to a plate which covered the
vessel. A large garden snail supported this severe confine-
ment nearly three years, being apparently dead all the time;
after which it revived upon being put into water, like the
.rest of its fellow captives.

This wonderful faculty however is not possessed by snails
of every description; this I discovered, by treating an aqua-
tic species, the helix putris, in the manner described above.
The preceding experiment was made in consequence of a
short memoir which I met with some years ago, in a volume
of the Philosophical Transactions of an older date. The

writer

ON TOJIPIDITY IN AINMALS. } 65

writer of this paper had observed accidentally, that some
snails, which had been long confined in a drawer, were found
to be alive after beiug immersed in water: the fact appeared
very singular to me, and I was desirous to ascertain the ac-
curacy of it more correctly by a direct experiment.

The proof of the second objection being now finished, I
am obliged by want of room to defer the remaining two to
a future opportunity.

JOHN GOUGH.

Middleshaw, 5th Feb, 1808,
SIR,

I Had the honour of presenting the following me-
moir to the Society of Nat. Hist. Edinburgh, in October,
1798; since which time it has come to my knowledge, that
this learned body is not in the habit of publishing its pa- •
pers ; and as the essay promises to establish the third and
fourth objections offered in my last letter to the received
theory of torpidity, I have transmitted it to your valuable
Journal.

And remain, &c.

JOHN GOUGH.

On the changes produced in the habits of animals by difference
of diet and other causes, together with the history of a rfo-
mesticated dormouse.

The remarks contained in the present essay are not the Introductory

Tesult of experiments instituted either to confirm or con- remark*

tradict any notion ; but were collected from observations

made on the general economy of the little quadruped under

consideration.

Having procured two dormice, mures avellanarii, in Ja- Manners of *

nuarv, 1792, which were caught in the woods but a few dayS pair of dormice

recently
before they came into my hands, I confined them in a cage caught.

furnished with a thermometer, and placed in a chamber
where no tire was kept. In this situation they were supplied
regularly with water and food, consisting of hazel-nuts and
biscuit. The weather in February being warm for the sea-
son

\66 ON TORPIDITY TV ANIMALS.

son at the beginning and end of the month, and frosty from
the l6th to the 25th, I had an opportunity to obsewe, that,
whenever the thermometer, which was attached to the cage,
fell to 4-2°, the dormice became inactive, and remained ap-
parently insensible as long as the heat of that part of the
chamber did not exceed the temperature here specified : but
as oft as the mercury reached !47°j they became very sus~
ceptible of external impressions, and awaked in the even-
ings, when they repaired to their stock of provisions, of
The pair killed which they consumed not a little. The same dry food was
treatnfentT1" ^judiciously persisted in through the succeeding summer ;
in consequence of which they grew sickly, and died before
• the winter commenced : so that I had not a second oppor-

tunity to attend to the economy of this couple during the
cold season.

A third dor- About the middle of April, 179-3, I obtained a third dor-

mouse more, ' r , 0 ., i r • i .

judiciously mouse fresh from the woods : former experience taught me
treated. to manage this in a manner more congenial to its constitu-

tion ; for in addition to the nuts and biscuit, it was constantly
supplied with green hazel-buds or raisins in spring ; with
ripe fruits, particularly cherries and pears, in sum rarer; and
with apples and raisins in winter. This generous diet not
*■ only preserved the creature in health and high condition,
but appeared to fortify it against the benumbing effects of
cold, which it supported the following winter much better
than the other couple had done formerly : for it never slept
more than 48 hours, and that but seldom, without visiting
the cup which contained its provisions.
Proof of the I now began to suspect the torpidity of the dormouse in

o jec wri. a wj|^ state, to be nothing but a custom imposed by neces-
sity on a constitution, which nature has intended to retain
life during the cold season of winter, with but little food
and an imperfect degree of respiration, as well as a languid
or perhaps a partial action of the sanguiferous system. The
preceding supposition can alone reconcile the difference of
manners observable in the dormice I had in 179c3, and that
which has been described above: for as soon as the neces-
sity of sleeping was removed, the propensity to become tor-
pid with cold disappeared in a great measure. Tiie uncom-
monly severe weather which ushered in the next year, viz.

1795,

ON TORPIDITY IN ANIMALS. 107

1795, confirmed the foregoing opinion apparently beyond
exception: for a constant use of a generous and plentiful
diet had by this time completely conquered the torpid ha-
bit, which the animal in all probability contracted in its
native habitation from hunger, or more properly from a state
of inactivity voluntarily imposed on itself, with a view to
husband its stock of nuts, which would be frequently too
soon exhausted but for this precaution. Notwithstanding
the hard frost of January, it brayed the co!d with wonderful
fortitude, or if the expression be thought less exceptionable,
with wonderful indifference ; for it awaked every evening,
when it consumed in the course of .the night a quantity of
food amounting to 100 or 120 grains, and frequently gnawed - '
the ice which covered the water in the cage: it **ven. uv.
took, in the coldest part of the month, to repair its nest,
which happened to receive an injury, and perfected the task
in one night,

Many instances are recorded of animals being compelled Instances of
-, , . r . , i .,. animals chang-

by strong circumstances to relinquish them cnaracte. ;s:ie h,ff their habits

manners, in order to act a part contrary in several impor-
tant points to the uniform conduct of their species. Liu-
nseus has preserved the memory of a tame fieldfare, tiirdifs
pilaris, belonging to a vintner in Stockholm, wijich learned
to drink wine, and became bald in consequence of this
strange beverage. I also knew a mastiff, which was equally
fond of ale, and never failed to get drunk when an oppor-
tunity offered. The hyaena lives on the roots of fritiilary,
in the unfrequented parts of Africa ; but in the vicinities of
populous cities it changes into a disgusting glutton, feeding
on filth and carrion. May not the nasty ways of the domes-
tic hog be considered as so many new habits introduced hv
similar causes in lieu of the cleaner manners of the wild
animal? The pied flycatcher, muscicapa atricapWa, lives
on soft seeds and insects in this country; but its food is
very different in Norway, especially during winter, when it
repairs to the habitations of men, where it sui>sis>ts on tle.^h
dried in the smoke. Signior Spallaazani converted a pigeon,
which is granivorous, into a carnivorous bird, by inducing
it in the iirst place to eat fresh meat, and afterward to giy/e
a preference to putrid animal -jsubttanccs. In reality, the

facts

X68 ON TORPIDITY IN ANIMALS.

facts which prove how little philosophers know of the prin-
ciple of accommodation, that regulates the animal economy
according to prevailing circumstances, are already nume-
rous, and observation bids fair to multiply them.
The diminish- I have shown in the present essay, that a quadruped re-
ed action of the markable for its torpidity may be rendered active at all sea-
brain thecause , , .,, . , * ,. .
of torpidity. sons Dy a P'entlTul and generous diet: perhaps a contrary

regimen properly managed might incline an animal, no less
remarkable for its activity, to become torpid at times. The
preceding suggestion will not appear absurd to those, who
view torpidity in the light it is here represented, I mean as
a periodical custom of prolonging sleep to an unusual
length, the respiration becoming at the same time slow and
feeble, and the heat of the body diminishing of conse-
quence. Some singular anomalies in the history of man
himself may be said to answer in part to the foregoing de-
scription, and to indicate an incipient propensity to become
torpid under certain circumstances. There are instances of
great insensibility arising from the operation of causes on
the system, which have an evident tendency to destroy the
vital power ; or which, to speak more properly, incapitate
the brain to generate this power in sufficient quantity, to
supply the various demands of the voluntary and involun-
tary functions : the little that is produced being expended
on those operations of the economy, which are absolutely
Proof ofobjec- necessary for the continuance of life. Dr. Plot relates the
turn 4th. case 0jf a p00r „',ri eight years old, who, being beaten by a

severe stepmother, and then sent hungry with some refresh-
ments to her father in the fields, could not refrain from eat-
ing part of them ; reflecting afterwards on the probable
consequences of her conduct, she proceeded no further on
her way, but retired to a neighbouring wood, and there fell
into a profound sleep, being oppressed with fear and sor-
row: in this state she remained for seven days, and, when
discovered, showed no symptoms of life, beside the softness
of her flesh, and flexibility of her joints. Dan. Ludovicus,
from whom Dr. Plot borrows this relation, happened to be
present, and succeeded in his attempts to recover this poor
creature. He first washed a glutinous phlegm from her
face with warm water, and cleared her mouth and nostrils

from

ON TORPIDITY IN ANIMALS. l6Q

from a viscid substance that obstructed them : a few spoon-
fuls of brandy were then administered ; after the second she
was heard to groan, after the third she opened her eyes,
and so came at length to herself by degrees (History of
Stafford shire, chap, viii, sect. 36). The same author has
also preserved another instance of a sleeper in the circle of
his own acquaintance. This is the history of Mary Foster,
of Admaston ; but her singular case is too imperfectly-
stated, to ascertain any thing more than the fact aud cause
of it- She remained in a profound sleep for fourteen days
and nights, after an equal period of fear and anxiety, occa-
sioned by the woman falling casually into a well ; and the
accident seems to have produced in her a disposition to tor-
por : for two years afterwards she slept two nights and a day
at Uttoxeter, but the reason of this relapse is omitted. The
annals of medicine furnish without doubt many more exam-
ples of a like nature ; but the few which I have specified
appear sufficient to prove, that torpidity is a mere habit, and
not a constitutional principle of the animal economy.

Supplementary remarks*

I was unacquainted, at the date of the preceding essay, An experiment
with an experiment made by Mr. Pallas, and mentioned by bv M- Pallas.
Mr. Cox, in his Travels through Russia. This celebrated
Russian naturalist conquered the torpid habit in a marmot,
by confining it through winter to a warm stove, and giving
it a plentiful supply ol food. If my recollection be correct,
the species of Mr. Pallas' s marmot is overlooked by Mr. Cox,
but the omission is of little moment, seeing the fact has
been ascertained by a philosopher of high reputation.

The natural history of the earless marmot, arclomys cit'd-
lus, also establishes the general proposition, viz. that tor-
pidity is a habit, and not a necessary propensity. These
animals imitate the manners of the hearth cricket; for those
that burrow in the fields fall asleep about the end of Sep-
tember, and appear again with the first symptoms of spring;
but when the same quadruped finds its way into a granary,
it remains active all winter.

The preceding observations agree very well with the sub- General re-
stance of the present essay, and my last on the same sub- mark.

ject:

170 OBJECTIONS TO THE MODERN CHEMICAL THEORY.

ject: but the experiment, ma''e on the dormouse, appears to
throw a light on the nature of torpidity; which perhaps, as
far as T know, can not. be derived from any other fact in
natural history : for according tr- it, a liberal use of nutritious
food will in time enable this little aainfal to support a degree
of cold much severer than that which benumbs the same
creature when wild and habituated to a meager diet. This is
a solitary instance of the surprising effects produced on the
constitution by regimen; from which we mar infer, that the
torpidity of the dormouse arises from the united operations
of cold and hunger ; but future observations must determine
how far other torpid animals are influenced by diet, before
we can pronounce the preceding explanation of torpidity to
be general.

II.

On the Nonexistence of Oxigen and Hidrogen, as Bases of par-
ticular Gasses; the Action of Galvanism ; and the compound
Nature of the Matter of Heat. In a Letter from G. S.

GlBBES, M. D.

To Mr. NICHOLSON,

Sir, Bath, Jan. 13, 1808.

Objections to JL OU have already done me the honour of publishing in
the theory yf vyour excellent Journal some opinions, which 1 maintain,
respecting the nonexistence of oxigen and hidrogen; and
the consequent failure of the Lavoisierian theory of chemistry
in explaining the phenomena, which are presented in that
science. I now take the liberty of sending some farther ob-
servations on the same subject, which lead me to conclude,
that my former opinions were well founded, and that the gene-
rallv received doctrine of the decomposition of water is not

~,, c r consistent with fact. I contend, that in no one experiment

liTeorv of the. l

composition of have we the least evidence, that the ponderable parts of oxi-

water not ^ n'1(jr0rreii air are substances differing from each other,

founded on . « ° .

fact. or in any respect peculiar substances; or thai water is a

compound resulting from the union of these two substances.

If

OBJECTIONS TO THE MODERN CHEMICAL THEORY. \J\

If this position can be proved, the Lavoisierian theory will
lose its fundamental support, and the whole superstructure
falls to the ground.

Tt is asserted, that the phenomena of galvanism, like Phenomena of
electricity, are owing to the presence or absence of one and J^-Tb^ine*
the same fluid, which constitute the positive and negative fluid,
sjdes.

If two bodies, acting upon a third produce different effects, This contra-
the bodies themselves must be different. dicted b? factB*

A different power is conducted into the water by the two
ends of the galvanic battery ; for, as the two pieces of ola-
tina remain unaltered, the effect on the water in the ga^-anic
experiment must be produced by two different powers, to
which the pieces of platina merely act as conductors. The
simple fact is then, that the one platina wire produces, when
placed in water, one particular air; and the other platina
wire, placed under similar circumstances, a different one:
the two powers therefore, conducted by the platina wires,
must be different.

Bodies in assuming an aeriform state require the union of The same sub-
different other bodies to constitute those characters which *1*^ ;Cn°t""dif.
distinguish them ; therefore these two different airs must ferent gasses,
have received from the two platina wires two different powers, 5ftjadd^tio11
to enable them, since water is concerned in the production substances.
©f both, to assume two different aeriform states. The two
airs, so formed, have certainly distinguishing characters ; for
the one supports combustion, and the other is a combustible
budy.

Water then is by the union of these two galvanic powers Fire a corn-
transformed into two aeriform bodies, in which reside all the j^olralvanic*
requisite circumstances of inflammation and combustion, powers.
Upon this combustion water is reproduced, and the two ai-
vanic powers form tire; fire therefore is composed of the two
galvanic powers.

Water then and one power of the pile produces oxigcn Water with

air; and water and the other power, l»idrogen air : and com- °.neof these
' . r » ft forms oxigen,

bustion is always produced by the union of these two powers, -with the other
The positive end of the galvanic battery then we assert, pro- hldr°gen-
duces in every, instance that effect on bodies which oxigen is
asserted to do ; and is not the basis or ponderable part of the

air,

172 OBJECTIONS TO THE MODE-UN CHEMICAL THEORY.

air, but the expansible power, which causes water to assume

Metallic calces t»at peculiar aeriform state. The same reasoning holds good

reduced by one with respect to the galvanic property of the negative end of

Si^the other". tne P''e> as m tne instance of metallic calces being reducible

to their metallic state; and we account for this by saying,

that the oxidated or positive state of the metal is destroyed

by its being saturated with the hidrogenous or negative

Bodies burnt p0vver 0f the pile. Jn short, bodies are burnt by the power

burnt by the or principle which comes from one end of the pile, and un-

other. burnt by the power or principle which comes from the other

end of the pile.
Metals render- Metals are combustible bodies, and in becoming oxides
busrible^by the tnev are burnt. Metals not easily burnt are rendered more
negative end combustible by being connected with the negative end of
epl the pile. Thus copper, which is easier converted into an ox-

ide than silver, will in ordinary cases take the acid from a
solution of silver in nitrous acid, and the silver will be de-
and thus their posited in its metallic form ; but if silver be rendered more
chaneed combustible by being connected with the pile, it will then

A supersede the copper in its attraction for the acid, and the

copper will be deposited in its metallic form. The above
proves, that a real and distinct power is communicated to the
silver by the pile.
Neutral salts Mr. Davy has shown, that neutral salts are decomposed
"alvaTiismedby by HW Powers ot> the pile ; that the acids appear on the posi-
tive side, and the bases on the negative; and that, when
muriatic salts are decomposed, the oxigenated muriatic acid
Galvanic appa- appears on the positive side. The galvanic apparatus re-
ritus decom- solves the matter of heat into its two- constituent principles,
teTof heat into which principles, being thereby freed from their affinity with
nstwopiinci- each other, are at liberty to enter into new combinations;
these combinations of the one, as with water in oxigen air,
in acids, metallic oxides, &c. ; and of the other in combusti-
Experiments ble bodies of all kinds, I shall attempt to illustrate by expe-
promued. riments, which I shall take the liberty of transmitting to you
in a future letter.

I am, Sir,

Yours, &c.

G. S. GIBBES.

III.

REMARKS ON THE CONSTELLATIONS. J73

II r.

Letter from N. R. D., containing some Remarks and Emen-
dations of his Communication in the Number for January.

To Mr. NICHOLSON.
SIR,

JL Take the liberty of sending you a few remarks on the Corrections &•
translation from Lalande, which you did me the favour of additions to the

t -»t paperonthe

inserting in the last number of your Journal. My only rea- Constellations
son for sending it originally to you was, the hopes of being inour8ist
useful, and the same motive induces me to point out the cor-
rections which have occurred to me.

In p. 3 I have given a somewhat different description from Gemini.
Lalande of the means by which we may find the constella-
tion of Gemini; because I think that in general it is much
more clear to the beginner, when the object to be found is
situate between two others, with which he is already ac-
quainted. I therefore ventured to alter the arrangement of
my author's directions, while I preserved the substance of
it: but it might have marked the line still more strongly, if
I had added with him, that it passes nearly through e and £
the two stars in the tail of the great Bear which are nearest
the body.

P. 5, 1. 18. Lalande describes the head of Andromeda as Head of An-
the " most northern" star in the square of Pegasus, and so dromeda.
it really is; but its declination so little exceeds that of 0 Pe-
gasi, that it would have been much more clear to have called
it the " N. E." star.

P. 3. line 6 from bottom. The "leg" of Ophiucus is Ophiucus.
substituted for the " foot," in consequence of my having
used Dr. Bevis's Uranographia Britannica. The eastern
foot is there placed in 10° or 11° of south declination. I
had not, when I wrote, the opportunity of consulting Flam-
stead's Atlas Ccelestis, or I should have made no alteration.
This circumstance will account for my having omitted the
notice of the two feet being on the ecliptic.

P. 9, 1. 12 from bottom. A line drawn from Capella * Ceti,
through the Pleiades will also *' pass south of a. Ceti." It
should have been said, as it is in the French, that it will

point

J74 REMARKS ON THE CONSTELLATIONS.

point to a. Ceti. The alteration was suggested by looking
through mistake, at the Hyades near Aldebaran, instead of
the Pleiades,
a Piscium. ?• 10. T'le direction for finding a Piscium was altered

from the wish before mentioned, of giving two known ob-
jects on opposite sides of that which was to be pointed out;
and the proximity of o Ceti made it very useful for this pur-
pose. 1 still think, that this description is better than La-
lande's, when » is brilliant ; but as that star is sometimes
invisible, the original should likewise have been added,
which says, that a Piscium will be found in the line drawn
from y, the foot of Andromeda, through the head of
Aries.

P. 10, 1, 13 from bottom. " Les deux precedentes " are
rendered " the two eastern" stars in the body of the great
Bear. This translation is only accurate when the constella-
tion is under the pole. The stars should therefore have been
described as those which are " farthest from the tail."

The above remarks may induce your readers to think,
that I have taken greater liberty with my original than I
have even given notice of in the short note at p. I: and as
it is a bold measure for an anonymous writer, to venture on
correcting what has been printed by an author of established
"Errours in La- fame like Lalande, it may be right to mention a few of the
lande. instances which occur in the text, to prove that some revi-

sion was necessary. In § 770, Aquila is described as being
"au milieu de la Lyre et du Cygne ;" there can be no
doubt, that this ought to be " au midi de la Lyre et du
Cygne." § 774. The tail of the Serpent is said to be
M vers l'occident," with respect to Ophiucus, when it cer-
tainly is towards the east. § 779* Aquarius is said to be as
far from the Dolphin as the Dolphin is from the Eagle ; but*
n,o one acquainted with the heavens will blame me, for sub-
stituting the Lyre in this place instead of the Eagle. — I took
considerable pains in comparing the translation with the
globe and the Celestial Atlas, and I hope therefore, that it
will be found in some parts more accurate even than the ori-
ginal, especially when the following additions are made and
errata corrected. 1 sincerely regret, that there should be
any occasion for correction, and I can only apologise by

stating,

ADVANTAGE OF GRAFTING CERTAIN TREES. 175

stating, that the copy was written out under a most unusual
press of business, which scarcely allowed me to finish it in
time to send it to you as soou as I had promised.

Jan. 15, 1808. **• R- D-

In p. 2, 1. 18, for points to read points nearly to. — p. 4,
1. 6, after horns add which are 8° apart.— ib, 1. 32, for first
read third.— p. 7, 1. 25, after and add of the.— p. 8, 1. 0,

for through read near: I. 23, for south-east read south-west :
1. 27, after 0 add a changeable star.— p. 9, 1. 13 from bott.

for 3d read 2d.— p. 10, 1. 7, for the Whale read Aries.—
p. 11, 1. 10, for 32° 2' read 33° 2'.

IV.

On the Advantages of Grafting Walnut, Mulberry, and
Chesnut Trees, By Thomas Andrew Knight, Esq,
F.R.S. $**

JlN the course of very extensive experience in the propaga- Grafts of bear-

tion of apple and pear trees, I found that the detached parts ing branches

, n . . do not form

of the bearing branches of old trees ot those species, when yoUng trees,

employed as grafts, never formed what could with propriety
be called young trees : the stocks appeared to afford nutri-
ment only; and the new plants retained, in all instances,
the character and habits of the bearing branches of which
they once formed parts; and generally produced fruit the
second or third year after the grafts had been insertedf,

I was therefore induced to hope, that the effects of time Applied to the
might be anticipated in the culture of several fruits, the trees speedy pcoduc-
of which remain unproductive during many years after they fmits
are planted: and that parts of the bearing branches of those,

detached

* From the Trans, of the Horticultural Society. Vol I, p 60.

-}• Columella appears to have known, that a cutting of a bearing branch
did not form a young tree ; for speaking of cutting-; of the vine (semina)
he says, "optima habentur alumbi*; secundaab humeri*; tertia summi
iu vite lecta, qux celerrime comprehend unt, et sunt feraciora, sed et
ouarn celerrime senescunt." De Arboribu?, chap. ■).

\JQ ADVANTAGE OF GRAFTING CERTAIN TREES.

detached from the old trees, and employed as grafts, would
still retain the character and habits of bearing branches.
Experiment Having therefore planted in the spring of 1799 some wal-

nut!* " nut trees> °* two years °W, in garden pots, 1 raised them up

to the bearing branches of an old walnut tree, by placing
them on the top of poles placed in the earth; and I grafted
them, by approach, with parts of the bearing branches of the
old tree. A union took place during the summer, and in the
autumn the grafts were detached from the parent stock.
The plants thus obtained were planted in a nursery, and,
without any peculiar care or management, pioduced both
male and female blossoms in the third succeeding spring,
and have since afforded blossoms every season. The frost
has, however, rendered their blossoms, as well as those of
other trees in their vicinity, wholly unproductive during the
last three years, and in the spring of 1805, almost wholly
With the iauU^estroyec^ tne w0°d °* tne preceding year. A similar expe-
freny« riment was made in the same year, but under many disad-

vantages, on the mulberry tree. I had not any young plants
of this tree, and therefore could only make the experiment
with scions of one year old ; and of these I had only two,
which had sprung from the roots of a young tree, in the pre-
ceding year. These were planted in pots, and raised to the
bearing branches of an old tree, in the manner I have already
described in speaking of the walnut tree. One of these
scions died ; the other, which had but very few roots, suc-
ceeded; and the young grafted tree bore fruit the third year,
and has continued annually productive. In the last spring I
introduced it into my vinery, where its fruit ripened, in the
greatest state of perfection, in the beginning of the present
month, [January, 1807].
Grafting by ap- Both the walnut and mulberry tree succeed so ill when
them ei,ttor grafted, unless by approach, that I can scarcely recommend
attempts to propagate them in any other way ; but when
they succeed by other modes of grafting, nearly the same
advantages will probably be obtained : the habit of the
bearing branch is, however, least disturbed by grafting by
approach.
Spanish ches- The Spanish ehesnut succeeds readily when grafted in

nut succeeds a|,110st any of the usual ways, and when the grafts are taken
any way.

from

_^ tyf&T'iPcA^/'

S'nMsom Thilos. Journal. VolM . PI V. p/j y.

J\ J\ Fig. 11

MlW

Fig. 3.

Fig. 2.

Z-JJ.. ptt-cA/i _yc€a^/e^ ual0rts??ze£e4S.

HERSCHRL ON COLOURED RINCS. \J~

from bearing brandies, the young trees afford blossoms in

the succeeding year : and I am much inclined to think, from

experiments I have made on this tree, that by selecting those

varieties which ripen their fruit early in the autumn, and by

propagating with grafts or buds from young and vigorous

trees of that kind, which have just attained the age necessary

to enable them to bear fruit, it might be cultivated with

much advantage in this country, both for its fruit and Valuable both
~ , ' tor us trim ana

timber. timber.

I have tried similar experiments on many other species of Tried on many-
trees, and always with the same result; and I entertain no other trees,
doubt, that the effects of time might be thus anticipated in maturity anti-
the culture of any fruit, which is not produced till the seed- cipated,
ling trees acquire a considerable age. For I am thoroughly
confident, from very extensive* and long experience, that the
graft derives nutriment only, and not growth, from the young
stock in which it is inserted ; and that with the life of the pa-
rent stock the graft retains its habits and its constitution.

Experiments for investigating the Cause of the coloured con-
centric Rmgs, discovered by Sir Isaac Newton, between
two Object-glasses laid upon one another. By William
Herschel, L.L.D. F.R.S.

( Concluded from p. W&.)

XIX. Of the Place where the different Sets of Rings are to
be seen.

JD>Y an application of the same course of the rays, we may pjacc wiiere
now also determine the situation of the place, where the dif- the different
ferent sets of rings are seen : for, according to what has been are seen.' &*
said in the foregoing article, the situation of the primary set
should be between the lens and the surface of the looking- . f

glass : and the place of the secondary on« at the metalline
coating of the lowest surface. To try whether this be ac-
tually as represented, let us substitute a metalline mirror
Vol. XIX.— March, 1809. N with

178 Ill.RSCIIEL ON COLOURED RINGS.

with a slip of glass laid upon it in the room of the piece of
looking-glass; and let there be interposed a short bit of
wood, one tenth of au inch thick, between the slip, of glass
and the mirror, so as to keep up that end of the slip which is
towards the light. This arrangement is represented in Pl.V,
fig. 9> where both sets of rays are delineated. Then i-f we in-?
terpose a narrow tapering strip of card, discoloured with ja-
pan ink, between the slip of glass and the mirror,, so as to
cover it at 7> we do not only still perceive the primary set,
but see it better than before: which proves, that, being si-
tuated above the slip of glass, the card below cannot cover it.
If on the contrary we insert the strip of card far enough, that
it may at the same time cover the mirror both at 4 and at 7,
we shall lose the secondary set, which proves, that its. situation
was on the face of the mirror.
Eye-glass re- When several sets of rings are to be perceived, by the same

quires a differ- eve_criass and they are placed at different distances, a parti-*
entadjustment J ° ,.' % . r.,v . . . _ ■ 1 . ,

for each set. cular adjustment of it will be required tor each set, in order

to see it well defined. This will be very sensible when we

attempt to see three or four sets, each of them situated lower

than the preceding; for without a previous adjustment to the

distance of the set intended to be viewed, we shall be seldom

successful; and this is therefore a corroborating proof of the

situation, that has been assigned to different sets; of rings.

XX. Of the Connection between different Sets of Rings.

Connexion be- It will now be easy to explain in what manner different
i ween different setg of ^^ are connected> and w\iy taey have been called

primary and dependent. When the incident rays come to the
point of contact, and form a set of rings., I call it the pri-
mary one: when this is formed, some of the rays are conti-
nued by transmission or reflection, but modified so as to con-
vey an image of the primary set with opposite colours for-
ward through any number of successive transmissions or re-
flections; whenever this image comes to the eye, a set of
lings will again be seen, which is a dependent one. Many
proofs of the dependency of the second, third, and fourth sets
of rings upon their primary one may be given; I shall only
mention a few.
P;oofs that all When two sets of rings are seen by a lens placed upon a

looking-

HERSCIIEL ON COLOURED RINGS. 179

looking-glass, the centre of the secondary set will always re- the ot*ier sets

main in the same plane with the incident and reflected rays primary TneV*

passing- through the centre of the primary one. If the point

of contact is changed by tilting, the secondary set will follow

the motion of the primary set; and if the looking-glass is

turned about, the secondary will be made to describe a circle

upon that part of tlie looking-glass, which surrounds the

primary one as a centre. If there is a defect in the centre

or in the rings of the primary set, there will be exactly the

same delect in the secondary one; and if the rays that

cause the primary set are eclipsed, both sets will be lost

together. If the colour of the primary one is changed, that

of the secondary will also undergo its alternate change, and

the same thing will hold good of all the dependent rings,

when three or four sets of them are seen, that have the same

primary one.

The dependency of all the sets on their primary one may
also be perceived, when we change the obliquity of the inci-
dent light; for the centres of the rings will recede from one
another when that is increased, and draw together when we
lessen it, which may go so far, that by an incidence nearly
perpendicular we shall bring the dependent sets of rings al-
most under the primary one.

XXI. To account for the Appearance of several Sets of Rings
with the same coloured Centres,

It has often happened, that the colour of the centres of Why several

difterents sets was not what the theory of the alternation of sets hav(r the ,
i 11 i i i • n i -r i same coloured

the central colours would have induced me to expect : I have centre.

seen two, three, and even four sets of rings, all of which had
a white centre. We are however now sufficiently prepared,
to account for every appearance relating to the colour of rings
and their centres.

Let an arrangement of glasses be as in figure 9. When
this is laid down so as to receive an illumination of day light,
which should not be strong, nor should it be very oblique, the
reflection from the mirror will then exceed that from the sur-
face of glass; therefore the primary set will be seen by the -
rays 6, 7, coming to the mirror at 7, and going through the
point of contact in the direction 7, 2, 3, which proves it to be
N 2 a set

180 MKUSCHEL ON COLOURED RINGS.

a set that is seen by transmission, and it will therefore luive a
white centre. The rays 1, 2*, 4, passing through the point of
contact, will also form a transmitted set with a white centre,
which will be seen when the reflection from 4 to 5 conveys it
to the eye. Hut these two sets have no connection with each
other; and as primary sets are independent of all other sets,
I have only to prove, that this secondary set belongs not to
the primary one which is seen, but to another invisible one.
This may be done as follows.

Introduce the black strip of card, that has been mentioned
before, till it covers the mirror at 7; this will takeaway the
strong reflection of light, which overpowers the feeble illu-
mination of the rays 1, 2, 3 ; and the real hitherto eclipsed
primary set, belonging to the secondary one with a white cen-
tre, will instantly make its appearance with a black one. We
may alternately withdraw and introduce again the strip of
card, and the centre of the primary set will be as often
changed from one colour to its opposite ; but the secondary
set, not being dependent on the rays 6, 7, will not be in the
least affected by the change.

If the contact should have been such as to give both sets
with orange centres, the introduction of the strip of card will
prove, that the set which is primary to the other has really a
green centre.

Another way of destroying the illusion is to expose the
same arrangement to a brighter light, and at the same time
to increase the obliquity of the angle of incidence; this
will give a sufficient reflection from the surface of the glas*
to be no longer subject to the former deceptive appearance;
for now the centre of the primary set will be black, as it
ought to be.

XXII. Of the reflecting Surfaces.

Situation of The ra>s °f Kjfht, tnat *°rm rings between glasses, must

the surfaces undergo certain modifications by some of the surfaces
£l,eflcct the through which they pass, or from which they are reflected;
aud to tind out the nature of these modifications, it will be
necessary to examine which surfaces are efficient. As we
see rings by reflection, and also by transmission, 1 shall begin
with the most simple, and ^how experimentally the situation

of

HKRSCIIEL ON COLOURED RINGS. ]gl

of the suiace that reflects, not only the primary but also the
secondary sets of rings.

Upon a slip of glass, the lowest surface of which was de-
prived of its polish by emery, I laid an object-glass of 21
feet focal length, and saw a very complete set of rings. I
then put the same glass upon a plain metalline mirror, and
saw likewise a set of them. They were consequently not
reflected from the lowest surface of the subjacent glass or
metal.

It will easily be understood, that, were we to lay the same
object-glass upon a slip of glass emeried on both sides, or
upon an unpolished metal, no rings would be seen. It is
therefore neither from the first surface of the incumbent
object-glass, nor from its lowest, that they are reflected; for The. reflecting
if they could be formed without the modification of reflec- under the point
tion from the upper surface of a subjacent glass or metal, of contact,
they would still be seen when laid on rough surfaces ; and
consequently, the efficient reflecting surface, by which we
see primary sets of rings, is that which is immediately under
the point of contact.

To see a secondary set of rings by reflection, is only an
inversion of the method of seeing a primary one. For in-
stance, when a lens is laid upon a looking glass, the course
of the rays represented in figure 8, pi. IV, will show, that
the rays, 1, 2, 3, 5, 6, by which a secondary set is seen, are
reflected about the point of contact at 3, and that the
lowest surface of the incumbent lens is therefore the effi-
cient reflecting one; and thus it is proved, that in either case
of seeing reflected rings, one of the surfaces that are joined
at the point of contact contributes to their formation by a
certain modification of reflection.

XXII T. Of the transmitting Surfaces,

It would seem to be almost self-evident, that, when a set Transmitting
of rings is seen by transmission, the light which occasions sur aces'
them must come through all the four surfaces of the two
glasses which are employed; and yet it may be shown, that
this is not necessary. We may, for instance, convey light into
the body of the subjacent glass through its first surface, and
fet it be reflected within the glass at a proper angle, so that

it

182 HERSCHEL ON COLOURED RINGS.

it may come up through the point of contact, and rcai h the
eye, having been transmitted through no more than three sur»
faces. To prove this I used a small box, blackened on the
inside, and covered with a piece of black pasteboard, which
\\ad a hole of about half an inch in the middle. Over this
hole 1 laid a slip of glass with a 56-inch lens upon it; and
viewed a set ot rings given by this arrangement very obliquely,
that the reflection from the slip of glass might be copious.
Then guarding the point of contact between the lens and the
slip of glass from the direct incident light, I saw the rings,
after the colour of their centre had been changed, by means
of an internal reflection from the lowest surface of the slip
of glass; by which it rose up through the point of contact,
and formed the primary set of rings, without having been
transmitted through the lowest surface of the subjacent glass.
The number of transmitting surfaces is therefore by this expe-
riment reduced to three; but I shall soon have an opportunity
of showing, that so many are not required for the purpose of
forming the rings.

XXIV. Of the Action of the first Surface,

Aetipn of the We have already shown, that two sets of rings may be seen
upper surface. ^v usjng a ]ens |4jd Up0n a slip of glass ; in which case, there-
fore, whether we see the rings by reflection or by transmis^
sion,nomore than four surfaces can be essential to their
formation. In the following experiments for investigating the
action of these surfaces I have preferred metalline reflection,
when glass was not required, that the apparatus might be
more simple.
This not af- Upon a plain metalline mirror I laid a double convex lens,

fected by a having a strong emery scratch on its upper surface. When I
' saw the rings through the scratch, they appeared to have a
black mark across them. By tilting the lens, I brought (be
centre of the rings upon the projection of the scratch, so that
the incident light was obliged to come through the sciatch to
the rings, and the black mark was again visible upon them,
but much stronger than before. In neither of the situations
were the rings disfigured. The stronger mark was owing to
the interception of the incident light, but when the rings had

received

HERSCHF.r. ON COLOURED RINGS. 183

received thai full illumination, the mark was weaker, because
in the latter case the rings themselves were probably com-
plete, but in the former deficient.

I placed a lens that had a very scabrous polish on one side, scabrousness,
but was highly polished on the other, upon a metalline mir-
ror. The defective side being uppermost, I did not find that
its scabrousness had a-uy distorting effect upon the rings.

I splintered off the edge of a plain slip of glass; it broke as or irregularity,
it usualty does with a waving, striated, curved slope coming
to an edge. The splintered part was placed upon a convex
metalline mirror of 2 inches focus, as in PI. V, fig, 10. The
irregularity of the striated surface, through which the incident
ray 1, 2, was made to pass, had very little effect upon the form
of the rings; the at rise appearing only like fine dark lines, with
hardly any visible distortion; but when, by tilting, the return-
ing ray, 2, 3, was also brought over the striated surface, the
rings were much disfigured. This experiment therefore seems
to prove, that a very regular refraction of light by the first
surface is not necessary; for though the rings were much dis-
figured, when the returning light came through the splintered
defect, this is no more than what must happen to the appear-
ance of every object, which is seen through a distorting
medium.

I laid the convex side of a plano-convex lens of 2*8-inch Altering the
•focus with a diameter of 1*5 upon a plain mirror, and when I denc^ ha^no
saw a set of rings, I tilted the lens so as to bring the point of effect,
contact to the very edge of the lens, both towards the light
and from the light, which, on account of the large diameter of
the lens, gave a great variety in the angle of incidence to the
rays which formed the rings; but no difference in their size
or appearance could be perceived. This seems to prove,
that no modification of the first surface in which the angle of
incidence is concerned, such as refraction and dispersion, has
any share in the production of the rings, and that it acts
merely by the intromission of light ; and though even this is
not without being influenced by a change of the angle, it
can only produce a small difference in the brightness of the
rings.

A more forcible argument, that leads to the same conclu- Further nro#f.

sion.

ened with
emery.

184, HERSCHEL ON COLOURED RINGS.

sion, is as follows. Laying down three 54-inch double con-
vex lenses, I placed upon the first the plain side of a plano-
convex lens of -g. inch focus; upon the second, a plain slip of
glass; and upon the third, the plain side of a plano-concave
lens also | inch focus. I had before tried the same experi-
ment with glasses of a greater focal length, but selected
these to strengthen the argument. Then, as nothing could be
more different than the refraction of the upper surfaces of
these glasses, I examined the three sets of rings that were
formed bv these three combinations, and found them so per-
fectly alike, that it was not possible to perceive any difference

The first sur- jn the size and colour. This shows, that the first surface of

face simply an . .

inlet to the *hc incumbent glasses merely acts as an inlet to the rays that

rays. afterward form the rings.

Surface roughr To confirm the idea, that the mere admission of light would
be sufficient, I used a slip of glass polished on one side but
roughened with emery on the other; this being laid upon a
21-feet object-glass, I saw a set of rings through the rough
surface; and though they appeared hazy, they were otherwise
complete in figure and colour. The slip of glass, when laid in
the same manner upon the letters of a book, made them ap-
pear equally hazy; so that the rings were probably as sharply
formed as the letters.

Having now already great reason to believe, that no modifi-
cation, that can be given by the first surface to the incident
rays of light, is essential to the formation of the rings, I made
the following decisive experiment.

Upon a small piece of looking-glass I laid half a double
convex lens of l6 inches focus, with the fracture exposed to
the light, as represented in figure 11. Under the edge of the
perfect part of the lens was put a small lump of wax, soft
enough to allow a gentle pressure to bring the point of con-
tact towards the fractured edge, and to keep it there. In this
arrangement it has already been shown, that there are two
different ways of seeing two sets of rings: by the rays 1, 2,
3, we see a primary set ; and by 1, 2, 4, 5, the secondary set
belonging to it : by the rays fj, 7, 2, 3, we see a different pri-
mary set ; and by 6', 7, 2, 4, 5, we see its secondary one.
That this theory is well founded has already been proved ;

but

Experimen-
tal!} crucis.

HERCIIRL ON COLOURED RINGS. 185

but if we should have a doubt remaining, the interposition of
any small opaque object upon the looking glass near the frac-
ture will instantly stop the latter two sets of rings, ami show
the alternate colours of the two sets, that will then be seen by
the rays 1, 2, 3, and 1, 2, 4, 5. Remove in the next place
the stop from the looking-glass, and bring the second shadow
of the penknife over the primary set, and there will then
only remain the two sets of rings formed by incident rays
which come from rj, and which have never passed through the
upper surface of the lens. Now, as both sets of rings in this
case are completely formed by rays transmitted upwards from
the coated part of the looking-glass without passing through
the first surface of the incumbent lens, the proof that the
modifying power of that surface is not required to the form-
ation of the rings, is established.

It can hardly be supposed, that the first surface of the lens The upper
should have any concern in the formation of the rings, when cessarv for Uvb
the rays are reflected from the looking-glass towards the eye; returning ray.
but the same experiment, that has proved that this surface
was not required to be used with incident rays, will show, that
we may do without it when they are on their return. We
need only invert the fractured lens, as in figure 12, when ei-
ther 1, 2, 4, 5, or 6, 7, 2, 4, 5, will convey the image of the
rings, after their formation, to the eye, without passing
through any part of the lens.

XXV. Of the Action of the second Surface*

As rings are formed when two glasses are laid upon each Action of the
other, it is but reasonable to expect, that the two surfaces at second surface,
least which are placed together should have an immediate
effect upon them ; and so much the more, as it has been ascer-
tained, that the first surface assists only by permitting light to
pass into the body of the glass. Some of the experiments,
that have been instituted for examining the action of the
iirst surface, will equally serve for investigating that of the
second.

The lens already used with a strong emery scratch being scratched,
again placed on the mirror, but with the injured side down-
wards, I found that the rings, when brought under the scratch,

were

186 HERSCIIEL ON COLOURED RINGS.

were not distorter]; they had only a black mark of the same
shape as the scratch across them.

Scabrous. 'J'he lens with a scabrous side was also placed again upon

the mirror, but with the highly polished side upwards, in this
position the scabrousness of the lowest surface occasioned
great irregularity among the rings, which were indented and
broken wherever the little polished holes that make up a sca-
brous surface came near them; and if by gently lilting the
lens a strong contact was prevented, the colours of the rings
were likewise extremely disfigured and changed.

is the distor- As we have now seen that a polished defect upon the second

tion occasioned surfacc will affect the figure of the rings that are under it, it

by the rings be- . °

ing Jeen Wtjl remain to be determined, whether such defects do really

throngh an ir- distort them bv some modification they give to the rays of
regular me- . .■* , " " *

.dium? light in their passage through them, or whether they only re-

present the rings as deformed, because we. see them through
a distorted medium, For although the scabrousness did not
sensibly affect the figure of the rings when it was on the first
surface, we may suppose the little polished holes to have a
much stronger effect in distorting the appearance of the rings
when they are close to them* The following experiment will
entirely clear up this point.
Effect of a v>o- Over the middle of a 22-inch double convex lens I drew a
nshrtltine. strong line with a diamond, and gave it a polish afterward)
that it might occasion an irregular refraction. This being
prepared, I laid a slip of glass upon a plain metalline mirror,
and planed th'e ltens with the polished line downwards upon
the slip of glass. This arrangement has been shown to give
The primary two sets of rings. When I examined the primary set, a
f1 rtd^and stron» disfiguring of the rings was visible; they had the
likewise the appearance of having been forced asunder, or swelled out, so
secondary. as to ^e much broader one way than another. The rings of
the secondary set had exactly the same defects, which, being
strongly marked, could not be mistaken. The centres of the
two sets, as usual, were «jf opposite colours, the first being
Mack, the second white; and all those defects, that were of
one colour in the first set, were of the opposite colour in the
second. When, by the usual method, I changed the colours
of the centres of the rings, making that of the primary white

and

HKRSCUKL ON COLOURED RINGS,

187

and of the secondary black, the defects in both sets Avere
still exactly alike, and as before; except that they had also
undergone the like transformation of colour, each having as-
sumed its opposite. It remains now only to show, that this
experiment is decisive; for by the established course of the
rays we saw the secondary set of rings when it had a white
centre by the transmitted rays marked 1, i>, 4, 5, in figure
13 ; and when it had a black one, by the reflected rays 6, 7,
2, 4, 5, of the same figure; but in neither of these two
cases did the rays come through the defective part of the
lens in their return to the eye.

This experiment proves more than we might at first be This proves it
aware of; for it does not only establish, that the second t0 ^ concern-
surface, when properly combined with a third surface, has a nation of the
modifying power, whereby it can interrupt the regularity of rulS*-
the rings, but also one whereby it contributes to their for-
mation ; for, if it can give an irregular figure to them by
transmitting its irregularly modified rays, it follows, that
when these rays are regularly modified it will be the cause of
the regular figure of the rings. Nay, it proves more ; for if
it modifies the figure of the rings by transmission, it modi-
fies them no less by reflection ; which may be seen by follow-
ing the course of the rays 6, 7> ~> 4, o; for as they do not
pass through the defective place of the lens, they can only
receive their modification from it by reflection. This opens Hence we may
a field of view to us, that leads to the cause of all these in- beled *?*

, . cause of the

tricate phenomena, of which in a second part of this paper phenomena.

I shall avail myself.

XXVI. Of the Action of the third Surface.

When a double convex lens is laid upon a plain metalline Action of the
mirror, that happens to have an emery scratch in its surface, 3tl surface«
we see it as a black line under the rings that are formed over
them. This shows, that, when a defect from want of polish
has not a power to reflect light in an irregular manner, it
cannot distort the rings that are formed upon it.

When I laid a good 21-feet object glass upon a plain slip Defects in this

that had some defects in its surface, the rings* 'in every part caPab,e ?f di*-

* t tortin,r the
of the object glass that was brought over them, were always rings,"

disfigured ; which proves, that a reflection from a defective

third

\

188 HERSCHKL 0NT COLOURED RINGS.

third surface has a power of forming distorted rings, and that
consequently a reflection from one that is perfect must have
a power of forming rings without distortion, when it is com-
bined with a proper second surface,
both of the pri< When the defective slip e# glass, with a perfect lens upon
condary sets" **> *** P^acec^ upon a metal line mirror, I saw the secondary
set affected by distortions of the rings that were perfectly
like those in the primary set ; which proves, that a polished
defect in the third surface will give modifications to the
rays that form the rings by transmission as well as by reflec-
tion.

XXVII. The Colour of the reflecting and transmitting Swr-
faces is of no consequence.

The colour of I laid seven 54-inch double convex lenses upon seven eo-

the surfaces of iourecl pjeces of plain glass. The colours of the glasses
no conse- f . ^ ? . n .

fjuence. were those which are given by a prism, namely, violet, in-

digo, blue, green, yellow, orange, aud red. The rings re-
flected from each of these glasses were in every respect
alike ; at least so far that I could have a black, a white, a
red, an orange, a yellow, a green, or a blue centre with
every one of them, according to the degree of pressure I
used. The lenses being very transparent, it may be admit-
ted, that the colours of the glasses seen through them would
in some degree mix with the colours of the rings; but the
action of the cause that gives the rings was not in the least
affected by that circumstance.
"* I saw the rings also by direct transmission through all the
coloured glasses except a dark red, which stopped so much
light, that I could not perceive them. The colour of the
glasses, in this way, coining directly to the eye, gave a strong
tinge to the centres of the rings, so that instead of a pure
white I had a blueish white, a greenish white, and so of the
rest ; but the form of the rings was no less perfect on that
account.

X X V 1 1 1. Of the Action of the fourth Surface.

of rhe We have already seen, that a set of rings may be com-

4th surface, pjttely formed by reflection from a third surface, without

the introduction of a fourth; this, at all events, must prove,

that

IIERfiCHEL ON COLOURED RINGS. 189

that ftrch a surface is not essential to the formation of rings,
but as not only in direct transmission, but also when two sets
of rings are to be seen, one of which may be formed by trans-
mission, this fourth surface must be introduced ; I have ascer-
tained by the following experiments how far the same has any
share in the formation of rings.

- In direct transmission, where the light comes from below,
the fourth surface will take the part which is acted by the
first, when rings are seen reflected from a metalline mirror.
Its office therefore will be merely to afford an entrance to the
rays of light into the substance of the subjacent glass ; but
when that light is admitted through the first, second, and
third surfaces, the fourth takes the office of a reflector, and
sends it back towards the point of contact. It will not be re-
quired to examine this reflection, since the light thus turned
back again is, with respect to the point of contact, in the
same situation in which it was after its entrance through the
first surface, when it proceeded to the same point ; but when
two sets of rings are to be formed by rays, either coming
through this point directly towards the fourth surface, or by
reflection from the same point towards the place where the
secondary rings are to be seen, it will then be necessary to
examine, whether this surface has any share in their forma-
tion, or whether these rings, being already completely form-
ed, are only reflected by it to the eye. With a view to Experiment

this, I selected a certain polished defect in the surface of a Y^haPollfl!e*
1 # # defect in tlus

piece of coach-glass, and when a 26-inch lens was laid upon surface.
it, the rings of the set it produced were much distorted.
The lens was then put upon a perfect slip of glass, and both
together were then laid upon the defective place of the coach-
glass. The rings of the secondary set reflected by it were
nevertheless as perfect as those of the primary set. It oc-
curred to me, that these rings might possibly be reflected
from the lowest surface of the perfect slip of glass, espe-
cially as by lifting it up from the coach-glass I still continued
to see both sets. To clear up this point, therefore, I took
away the slip, and turning the defective place of the coach-
glass downwards, produced a set of perfect rings between
the lens and the upper surface of the coach-glass, and
brought it into such a situation, that a secondare set must

be

j(j() Hir.jiscni;i. oft vohcmiv.n king*.

be reflected from the defective i>i;ice of the lowest surface.

This being obtained, tlie rings of tins set were again as well

formed, and as free from distortions* as those of the primary

set.

■Refraction of Upon a plain metalline mirror I laid down two lenses, one

ihe4thsur%» a planoconvex, the other a pluno-coneave, both of 2*9 inches

has little or no . .

rtiect. focus, and having the plain side upwards* When two 21-inch

double convex glasses were laid upon them, the secondary

sets of both the combinations were of equal size, and perfectly

like their primary sets; which proves, that the refraction of

the fourth surface is either not at all concerned, or at least

has so little ati effect in altering the size of the rings that it

cannot be perceived.

The result oi^ the foregoing- experiments, relating to the

action of the several surfaces, is,

General re- i. That only two of them are essential to the formation of

sulls* concentric -rings.

II. That these two must be of a certain regular construc-
tion, and so as to form a central contaet.

III. That the rays from one side, or the other, must either
pass through the point of contact, or through one of the
surfaces about the same point to the other to be reflected

. from it.

I V. And that in all these cases a set of rings will be formed,
having their common centre in the place where the two sur-
faces toueh each other.

XXIX. Considerations that relate to the Cause of the for-
mation of concentric Rings

Inquiry con-
cerning the
cause of the

It is perfectly evident, that the phenomena of concentric
rings must have an adequate cause, either in the very nature
or motion of the rays of light, or in the modifications that
are given to them by the two essential surfaces that act upon
them at the time of the formation of the rings.

This seems to reduce the cause we are looking for to an
alternative, that may be determined; for if it can be shown,
that a disposition of the rays of light to be alternately re-
flected and transmitted eannot account for the phenomena,
which this hypothesis is to explain, a proposition of account-
ing for them by modifications that may be proved, even on

tbe

III.RSCHEI. ON COLOURED RINGS. JQ\

the very principles of Sir. I. Newton, to have an existence,
will find a ready admittance. I propose, therefore, now to
give some arguments, which will remove an obstacle to the
investigation of the real cause of the formation of the con-
centric rings; for after the very plausible supposition of the
alternate lits, which agrees so wonderfully well with a num-
ber of facts that have been related, it will hardly be at-
tempted, if these should be set aside, to ascribe some other
inherent property to the rays of light, whereby we might
account for them ; and thus we shall be at liberty to turn
our thoughts to a cause, that may -be found in the modifi-
cations arising from the action of those surfaces, which have
been proved to be the only essential ones in the formation of
rings,

XXX. Concentric Rings cannot be formed by an alternate
Reflection and Transmission of the Rays of Light.

One of the most simple methods of obtaining a set of con- They cannot
centric rings is, to lay a convex lens on a plain metalline ,e ormed b>'
mirror; but in this ease we can have no transmission of rays, flection and
and therefore we cannot have, an alternate reflection and transmission of
transmission of them. If to get over this objection it should ','
be said, that, instead of transmission, we ought to substitute-
absorption ; since those rays, which in glass would have been
transmitted, will be absorbed by the metal, we may admit
the elusion: it ought however to have been made a part of
the hypothesis

XXXI, Alternate Fits of easy Reflection and easy Trans*
?nissiofi9 if they exist, do not exert themselves according to

various Thicknesses of thin Plates of Air.

■

In the following experiment, I placed a plain well polished If fits of easy
piece of glass 5'ti inches long, and 2'3 thick, upon a plain reflection and

_i li- • m 1 , , • , , , »• transmission

metalline mirror of the same length .with the glass; and in exist, they do

order to keep the minor and glass at a distance from each not exert

• " themselves ac-

otlier, I laid between them, at one end, a narrow strip of cording to va-

sueh paper as we commonly put between prints. The thick- rious tl»cktus-

c i • I r* l n ' ses of thin

ness or that which J used was the 040th p&rt ot an inch ; plates of air.

for 128 folds of it laid together would hardly make up

two tenths. Upon the glass I put a 39-inch double convex

lens ;

jQO HER9CHEL Off COtOl'RED RfXG'3*

lens ; and having exposed tins combination to a proper light,

I saw two complete sets of coloured rings.

In this arrangement, the rays which convey the secondary

set of rings to the eye must pass through a thin wedge of

air, and if these rays are endowed with permanent fits of

Change of easy reflection, and easy transmission, or absorption, their

thickness in exertion, according to Sir I. Newton, should be repeated at

capable of af- eveiT different thickness of the plate of air, which amount-

fecting the co- to the ---g}yj part of an inch, of which he says, " Hcec est

N/Ihypothe- crassitudo aeris in primo annulo obscuro radiis ad perpendi-

s"»s culum ineidentibus esibito, qua parte is annulus obscuris-

simus est." The length of the thin wedge of air, reckoned

from the line of contact, to the beginning of the interposed

strip of paper, is 5*2 inches, from which we calculate, that

it will have the above mentioned thickness at TT of an inch

from the contact ; and therefore at T!T, y\, ^5T» /t> tt» tt»

&c. we shall have the thickness of air between the mirror

and glass equal to -ry-gW* Tyvinnr> ty Aoo» ttiW* &c. ;

of which the same author says, that they give " crassitudi-

nes aeris in omnibus annulis lucidis, qua parte illi lucidis-

sime sunt.'* Hence it follows, that, according to the above

occurred at hypothesis, the rings of the secondary set, which extended

ies> over a space of *14 of an inch, should suffer more than seven

interruptions of shape and colour in the direction of the

wedge of air.

In order to ascertain, whether such an effect had any e'

istence, I viewed the secondary set of rings upon every part

of the glass-plate, by moving the convex lens from one end

of it gradually to the other; and my attention being parti-

withoutpro- cularly directed to the 3d, 4th, and 5th rings, which were

ducing the ef- extremely distinct, 1 saw them retain their shape and colour
feet.

all the time without the smallest alteration.

The same experiment was repeated with a piece of plain
glass instead of the metalline mirror, in order to give room
for the fits of easy transmission, if they existed, to exert
themselves; but the result was still the same; and the con-
stancy of the brightness and colours of the rings of the se-
condary set plainly proved, that the rays of light were not
affected by the thickness of the plate of air through which
thev passed.

XXXIT.

HERSCHEL ON COLOURRD RINGS. ]Q3

XXXII. Alternate Fits of easy Reflection and easy Trans-
mission, if they exist, do not exert themselves according to
various Thicknesses of thin Plates of Glass.

I selected a well polished plate of coach glass 17 inches No fits exert
long, and about 9 broad. Its thickness at one end was 33, cSglova^
and at the other 31 two hundredths of an inch ; so that in rious thick-
its whole length it differed T^ of an inch in thickness. By "fg^°f P
measuring many other parts of the plate I found, that it was
very regularly tapering from one end to the other. This
plate, with a double convex lens of 55 inches laid upon it,
being placed upon a small metalline mirror, and properly
exposed to the light, gave me the usual two sets of rings.
In the secondary set, which was the object of my attention,
I counted twelve rings, and estimated the central space be-
tween them to be about V± times as broad as the space taken
up by the 12 rings on either side ; the* whole of the space
taken up may therefore be reckoned equal to the breadth of
40 rings of a mean size: for the 12 rings, as usual, were
gradually contracted in breadth as they receded from the
centre, and, by a measure of the whole space thus taken up,
1 found, that the breadth of a ring of a mean size was about
the 308th part of an inch.

Now, according to Sir I. Newton's calculation of the ac-
tion of the fits of easy reflection and easy transmission in
thick glass plates, an alternation from a reflecting to a trans-
mitting fit requires a difference of tttttt Part pf an inch in
thickness* ; and by calculation this difference took place in
the glass plate that was used at every 80th part of an inch
of its whole length; the 12 rings, as well as the central co-
lour of the secondary set, should consequently have been
broken by the exertion of the fits at every 80th part of an
inch ; and from the space over which these rings extended,
which was about *13 inch, we find that there must have been
more than ten such interruptions or breaks in a set of which
the 308th part was plainly to be distinguished. Put when
I drew the glass pjate gently over the small mirror, keeping .

# Newton's Optics, p 277.

Vol. XIX— March, 1808. O the

194 HERSCHEL ON COLOURED RINGS*

the secondary set of rings in view, I found their shape and
colour always completely well formed.

This experiment was also repeated with a small plain glass
instead of the metalline minor put under the large plate. In
this manner it still gave the same result, with no other differ-
ence but that only six rings could be distinctly seen in the
secondary set, on account of the inferior reflection of the sub-
jacent glass.

XXXIII. Coloured Rings may be completely formed with~
out tlie Assistance of any thin or thick Plates^ either of Glass
or of Air.

The rings may The experiment I am now to relate was at first intended

be formed to be reserved for the second part of this paper, because it

•without thick 5 n .

or thin plates properly belongs to the subject of the flection of the rays

of glass or air. 0f light, which is not at preseut under consideration; but
as it particularly opposes the admission of alternate fits of
easy reflection and easy transmission of these rays in their
passage through plates of air or glass, by proving, that their
assistance in the formation of rings is not required, and also
throws light upon a subject, that has at different times been
considered by some of our most acute experimentalists, I
have used it at present, though only in one of the various
arrangements, in which I shall have occasion to recur to it
hereafter.
Experiment of Sir I. Newton placed a concave glass mirror at double its
Sir I.Newton, f0CB\ iength from a chart, and observed, that the reflection
of a beam of light admitted into a dark room, when thrown
upon this mirror, gave " four or five concentric irises or
'* rings of colours like rainbows*." He accounts for them
by alternate fits of easy reflection and easy transmission ex-
erted in their passage through the glass plate of the concave
mirror f.
of the duke of ^ie Duke de Chaulnes concluded from his own experi-
Chaulnes, ments of the same phenomena, " that these coloured rings
depeuded upon " the first surface of the mirror, and that the
u second surface, or that which reflects them after they had
, " passed the first, only served to collect them and throw them

* Newton's Optics, p. 265. f Ibid, p. 277.

a upon

HERSCHEL ON COLOURED RINGS. ]£5

" upon the pasteboard, in a quantity sufficient to make them
" visible*."

Mr. Brougham, after having considered what the two au- of Brougham,
thors I have mentioned had done, says, "that upon the whole
" there appears every reason to believe, that the rings are
" formed by the first surface out of the light, which, after
'* reflection from the second surface, is scattered, and passes
" on to the chart f."

My own experiment is as follows. I placed a highly po- of the author,
lished 7 feet mirror, but of metal instead of glass, that I
might not have two surfaces, at the distance of 14 feet from
a white screen , and through a hole in the middle of it one
tenth of an inch in diameter I admitted a beam of the sun
into my dark room, directed so as to fall perpendicularly on,
the mirror. In this arrangement the whole screen remained
perfectly free from light, because the focus of all the rays,
which came to the mirror, was by reflection thrown back '
into the hole, through which they entered. When all was
duly prepared, I made an assistant strew some hair-powder
with a puff into the beam of light, while I kept my attention
fixed upon the screen. As soon as the hair-powder reached
the beam of light, the screen was suddenly covered with
the most beautiful arrangement of concentric circles, dis-
playing all the brilliant colours of the rainbow. A great
variety in the size of the rings was obtained by making the
assistant strew, the powder into the beam at a greater dis-
tance from the mirror; for the rings contract by an increase
of the distance, and dilate on a nearer approach of the pow-
der.

This experiment is so simple, and points out the general
causes of the rings, which are here produced, in so plain a
manner, that we may confidently say they arise from the
flection of the rays of light on the particles of the floating
powder, modified by the curvature of the reflecting surface
of the mirror.

Here we have no interposed plate of glass of a given
thickness between one surface and another, that might pro-

* Priestley's History, &c. on the Colours of thin Plates, p. 515.
, + Phil. Trans, for 1796, p. 216.

O 2 ducc

]g6 KERSCHEL ON COLOURED RINGS.

duoe the colours by reflecting some rays of light and trans-
mitting others; and if we were inclined to look upon the
distance of the particles of the floating powder from the
minor as plates of air, it would not be possible to assign any
certain thickness to them, since these particles may be spread
in the beam of light over a considerable space, and perhaps
none of them will be exactly at the same distance from the
mirror.
(1 I shall not enter into a further analysis of this experiment,

as- the only purpose for which it is given in this place is to
show, that the principle of thin or thick plates, either of air
or glass, on which the rays might alternately exert their fits
of easy reflection and easy transmission, must be given up,
and that the fits themselves of course cannot be shown to
have any existence.

► XXXIV. Conclusion,
Newton's the- It will hardly fee necessary to say, that all the theory re-

and°intersiice» ^a^nS to tn^ s*ze °^ tne Parts or* natural bodies and their in-
of bodies, terstices, which Sir I. Newton has founded upon the exist-
founded or i fits ence 0f £ts 0f ^gy reflecti0n and easy trasmission, exerted

of easy reflec- . , .

tion aid trans- differently, according to the different thickness 01 the thm
mission of plates of which he supposes the parts of natural bodies to
ported by fact, consist, will remain unsupported; for if the above mentioned
fits have no existence, the whole foundation, on which the
theory of the size of such parts is placed, will be takeir away;
and we shaft consequently have to look out for a more firm
basis, on which a similar edifice may be placed. That there
is such a one we cannot doubt; and what I have already said
will lead us to look for it in the modifying power, which the
two surfaces, that have been proved to be essential to the
formation of rings, exert upon the rays of light. The Second
Part of this Paper, therefore, will enter into an examination
of tlie various modifications, that light receives in its approach
to, entrance into, or passage by, differently disposed surfaces
or bodies ; in order to discover, if possible, which of them
may be the immediate cause of the coloured rings that are
formed between glasses.

VI.

DESCRIPTION OF A NEW CALORIMETER. ] 97

VI.

Description of a newly .invented Calorimeter; with Experi-
ments to prove, that an increased Capacity, for Caloric
accompanies an Incrcafe of Temperature. By Joseph
Ueade, M. D.

SIR, Edinburgh, Jan. 22, 1808.

I-
Beg leave to communicate, through the medium of your

very interesjt'mg an(I scientific Journal, the invention of a

calorimeter, -rree from those inaccuracies incident to the ap- Defects of the

paratus of Messrs. Lavoisier and Laplace, in which it was apparatus of
: .: '. , . . . r ... LavuLbier and

impossible to guard against errours arising from capiw^ify^ , Laplace.

attraction, from the process of freezing and thawing pro-
ceeding at the same period, and likewise from, the influence
of a current of atmospheric air. In this communication I
will confine myself to a summary description of the appa-
ratus, and of a discovery deduced from it, which must in-
fluence in a most important manner, if proved, the investi-
gations of caloric ; that, contrary to received opinion, water Capacity of
increases in capacity from the thermometric range of 32 t° ri? increas/s
212, in a just rate for every degree of temperature commu- uniformly with
nieated. its temPera"

Dcscription of the Calorimetbr, ichich is to be formed of thin
sheets of Brass or Tin.

The innermost compartment No. 1, PI. V, tig. 1,- designed T-te catoriinfc*
for the fluid to be subjected to experiment, is to be stopped CT
with a thermometric cork, a, or, what is better, a thermo-
meter surrounded with chamois leather, and made to fit
accurately the aperture. The second compartment, No. 2,
holds a quantity of water, and is likewise to be stopped by
a thermometric cork, b, made air-tight by sealing wax, as
this water is not to be removed from the compartment during
the course of the experiments.

The external compartment, 3, is designed to act as an
imperfect conductor of caloric, and is to have a coating of

list

198 DESCRIPTION OF A NEW CALORIMETER.

list or flannel between the sheets of brass, which, combined
with the confined air. renders the instrument extremely accu-
rate, a minute elapsing before the thermometer fell 1 degree
at 150°. Therefore in experiments scarcely requiring that
time, there can be no abstraction of any consequence by
the atmosphere.
Method of When we wish to estimate the specific caloric of two

comparative fluids, suppose oil and water, we bring the calorimeter to
specific heat of the precise temperature of 32°, 40°, 50°, or any other we
two fluids. desire> indicated by the two thermometers. We then fill
the interior compartment, No. 1, with water at 212°, and
immediately stop it with the therm ometric cork, a. After
agitating the apparatus for about the space of 1 J minute in
a horizontal position, the thermometers indicate the rise
experienced by the water at 50° in the second compart-
ment, and the number of degrees lost by the water at 212°
in the interior. Suppose the calorimeter be raised from 50°
to 80°, we take that number as the specific caloric of water.
We then pour the water from the interior compartment,
and again reduce the temperature of the apparatus to 50°,
which is speedily accomplished, by pouring cold water into
the innermost compartment, until the thermometers are re-
duced to the desired point. We are next to fill the interior
compartment with oil at 212°; and if, after agitation, on
examining the two thermometers, we find the temperature
raised, suppose to 60°, we easily find the specific caloric of
oil compared with water. T? .«s taking water as the stan-
dard, in a short time all fluids may be examined. By sub-
Solids and cor- stituting an iron cage, solids may be subjected to ex per i-
rosive fluids rnent; so likewise may fluids, which act chemically on metals,
bTexandned! by enclosing them in a glass vessel.

Th uth re - ' am at Present engaged in a series of experiments, which
ga^- d in a se- I hope soon to be enabled to lay before the public. Here
s of expen j,ne rea(]er js to take notice, that I have only used ideal
numbers, more clearly to illustrate trie mode of operating
with the apparatus, and by no means indicative of the real
specific calouc of oil and water. I will end this part of my
communication by remarking, that in this instrument the
inaccuracies arising from abstraction of caloric by the at-
mosphere and vessel are obviated, which was impossible by

means

|N

ments.

DESCRIPTION OF A NEW CALORIMETER* ]QQ

means of mixture; for in pouring the hot liquid into the in- Inaccuracies

terior chamber, the pipe of the kettle may enter it, so ttf °bviatedb7

1 r J ' this apparatus.

entirely to prevent the abstraction of heat, and the vessel

must act in a similar manner on both fluids.

It is one of the most important questions in chemistry, to Whether the

determine, whether or not the capacities of fluids are pei*~-"PjCI'ies of

r r fluids be per-

manent from 32° to 212°: or in other words, whether 10 manent from

degrees of caloric, added to water at 32°, will produce the [|j* ^mng to
same elevation of temperature, as 10 degrees thrown into the point a pro-
same quantity at 200°. Most chemists are of opinion, that b^dto be
water changes its capacity at two points only, in passing The affirma_
from the solid to the fluid, and from the fluid to the aeri*- tive generally
form state ; and consequently, that there is a permanency of beheved>
capacity between the thermometric range of the freezing
and boiling points. Drs. Crawford, Black, Irvine, de Luc,
&c. thought they decidedly proved this to be the fact, by a
number of experiments; for on mixing equal quantities of
water at different temperatures, they found nearly a mean
produced. " The air of the room," says Dr. Crawford, Dr. Crawford's
** being 6l'5°, a quantity of water, weighing 13lbs. lOjoz. experiment,
was heated in a slight tinned iron vessel, that had a cover of
the same metal closely adapted to it, a thermometer being
inserted in the centre of the cover by means of a cork.
When the water was raised to the desired temperature, it
was gently agitated, that every part of it might be brought
to the same heat. The thermometer immersed in it point-
ing precisely to 120*6°, an equal quantity of cold water at
50*9°> the parts of which were also brought by agitation to
a common temperature, was mixed with the warm, by pour-
ing it into the tinned vessel in which the latter was contain-
ed. When the mixture was reduced, by agitating it with a
wooden rod to a mean heat, its temperature at the end of
one minute was 89*8°. Allowing therefore -066° for the
heat lost in the first minute, we have 89*866° for the true
temperature of the mixture. If the thermometer at the
moment of immersion bad indicated the exact arithmetical
mean it would have stood at 89*8.*'*

I will not here enter into the many difficulties and sources Remark.
of inaccuracy attendant on this method by mixture, but

* Cravrford on Animal Heat.

merely

200 DESCRIPTION OF A NEW CALORIMETER.

merely observe,. that when we consider the quantity of calo-
ric unavoidably carried off, the coming so near an exact
mean «t the end of one minute is very surprising.
Dr. Crawford I will now endeavour to demonstrate by direct experi-

mistaken, and ments, that an increase of capacity does invariably take place

his data erro- . . . P ,

neous. in a just raUo to the increase of temperature; and in the

second place, that a mean, or an approximation to it, may
result as well from a gradual increase of capacity, as from
a permanency : consequently, that Dr. Crawford's experi-
ments and mathematical propositions are founded on false
data.

Experiment ivhich proves the progressive Increase of Capa-
city.

Experiment to The calorimeter being at the precise temperature of 48°,
which was also that of the room, I filled the interior com-
partment, No. 1, with water from a boiling kettle at 212°,
and having closed it as before represented with a thermome-
tric cork, I agitated the apparatus well for about the space
of lj minute, in a horizontal position, when the two ther-
mometers indicated 97°. Therefore the water at 212° had
lost 115°, which, being communicated to the water at 48°
in the second compartment, had raised its temperature 49
degrees. Having taken down these numbers, I poured out
the water from the interior compartment, and brought the
s calorimeter to the exact temperature of 150°, and again
filled the interior compartment with water from the kettle
at 212°; when, after brisk agitation as before, I found the
temperature to be 166°. Therefore in this experiment the
water at 212° had lost 46 degrees, which, being communi-
cated to the water in the second compartment at 15Q°,
raised its temperature but 16 degrees; whereas if equal in-
crements of caloric produced equal increments of tempera-
ture, or in other words if the capacity were permanent, it
should have raised it 19tt°t> which is easily demonstrated by
the following calculation.

If 115 degrees raise water 49 degrees, what should 4G
raise it ? — Answer, 19rW'

Here it is obvious, that the difference between lG and
19rrV> is the difference between the capacity of water at 48°

and

DESCRIPTION OF A NEW CALORIMETER. £01

find the same quantity of wat^r at 1.50°, in the proportions
used in the calorimeter. Or that upwards of '3 degrees be-
came latent, according to Dr. Black ; or, what is more
simple and philosophical, went to supply the increased ca-
pacity.

Having performed this and a number of other experiments The result con-
at different temperatures, with similar results; and also hav- ^™ed by ^ar*
irig repeated them before a most accurate and scientific ex- merits.
perimenter, for whose opinions I have the highest respect;
and having found them all to coincide, I may justly infer,
that capacities are not permanent from the freezing to the
boiling point.

I now proceed to«show, that a mean, or an approximation Mean maybe
to it, may be produced by a gradual increase of capacity. opacity in-

If I mix water at 100° with water at 50° in equal propor- crease regulat-
ions, a mean of 75* may result. Here 25 degrees with a -v'
larger capacity are lost by the water at 100% which go not
only to supply the 25 degrees gained by the water at 50°,
but also to fill up that increased capacity, which the water
at 50° experienced, to bring its capacity from the freezing
point up to an equality of 75° ; and we may easily conceive,
that they may 60 nicely* balance*, as even to produce a mean.
Dr. Crawford entirely forgot this increased capacity gained
by the water at 50°. This may be more clearly demonstrated
by two diagrams, the one representing Dr. Crawford's
theory, the other mine.

Suppose a and g in the parallelogram, PI. V, fig. 2, to E>r- Crawford's
represent the thermometric range, a b are equal te c e7, and
c d to e f and e f to g h ; therefore, if these are equal to
one another, and represent the capacities, the capacities are
also equal. This may be all very true ; but as similar ef- The proof de-
fects may arise from different causes, I will endeavour to fective«
show, how a mean may be produced by a progressive increase
of capacity.

Suppose a g, fig. 3, to represent the thermometric range The author's
from 32° to 100° ; No. 4 the capacity of 100°, No. 3 that theory*
of 75°, and No. 2 that of 50°, although a b is not equal
to c </, nor c d to ef but if we produce from g *h to i,
g i is equal to c d, and if we produce g i to &, g k is equal
to a b. To demonstrate this in another point of view,

if

£02 DESCRIPTION OF A NEW CALORIMETER.

if we add water at 100°, represented by space 4, to water at
50°, represented by space Sj ; J5 degrees taken from space 4
of large capacity, not only go to fill up space 3, represent-
ing 759> but also to till up space 1, the increased capacity
gained by 50° in rising from the freezing point.

Although geometrical figures are no evidence of the truth
of a chemical doctrine, and should be avoided unless tending
tp illustrate the subject, yet I thought it necessary to call
them to my aid, the uore especially as Dr. Crawford has
dwelt on them at xnt length*.

Other fluids From these jenments we may analogically infer, that

obey a similar . ., , , , n ■ , . ,

law# similar laws regulate other fluids in a greater or less degree;

and that neither the mercurial, nor any other thermo-
meter, is a faithful index of the quantity of caloric. Thus
if the capacity of water increase, it does not bespeak the
quantity of caloric thrown in at different temperatures. But,
as this is a most important investigation, I will defer the dis-
cussion of it to a more voluminous detail; for, should my
experiments undergo the ordeal of critical investigation, and
be established as facts, the thermometer must be regulated
according to the increasing- capacity of the fluid, before we
can determine the exact quantity of caloric communicated,
and there must also be some other method adopted for prov-
ing the regularity of mercurial expansion.
The apparatus I •HI conclude by remarking, that the apparatus abstract-
lost more calo- efi more caloric in rising from 48° to 97°, than from 150° to
than at a high l66°, and therefore, in that respect, there can be no source
temperature. 0f fallacy.

Sir, I beg leave to remain,

Your very obedient servant,

JOSEPH READE, M.D.

Dimensions of P. S. The calorimeter I used held in the interior com-

the calonme- partment, No. 1, 6oz. of water, and in the second ]0| oz.
ter used. r . „ . . . x

consequently, if equal quantities were used, the increase

would be much more.

VII.

* The simple statement of the argument is, that, if the capacities an-
swering to any successive number of degrees of the thermometer be
supposed to increase by the augmentation or addition of any constant

quantity,

ON VARIOUS SPECIES OF CINCHONA. Q03

VII.

Experiments on the various Species of Cinchona: by Mr. Vau-

QUELIN.

(Concluded from page 120. J

appearances exhibited on a more minute examination by tJte infu- jjarks thatpre-
sion and decoction of different sptcies of cinchona, that prcci- cipitate nei-
pitate neither infusion of tan nor tartarised antimony. emetic tartar.

X HESE sorts of bark impart to cold water a red colour, Macerated in
frequently a yellowish red, sometimes a brown red. Water water,
thus loaded with the soluble part of these barks frolhs on
agitation like wort. Its taste is bitter, and more or less as-
tringent, this differing in the different sorts.

Left to stand in an open vessel, or in a close one if not
full, it soon grows mouldy, and is covered with a greenish
pellicle.

Some of them are perceptibly reddened by infusion of lit- Some of them
mus, which announces the presence of a free acid. acid-

Alcohol, mixed with these infusions in the proportion of two precjpitatedby
parts to one, precipitates a grayish substance, which grows alcohol,
black on desiccation. The fluid is left more clear, and of a
purer red. This indicates the presence of mucous matter.

In those infusions which have an acid a small quantity of By alkali.
caustic alkali lorms a red precipitate inclining to violet : but
a large quantity of the reagent redissolves this precipitate, and
renders the colour of the infusion more intense.

Subjected to evaporation they become higher coloured ; Evaporate(i
and, attei being thus boiled down, they let tall on cooling a form a deposit
very bitter brown substance, which dissolves readily in alco- on co° * 8-
hoi, particularly with the assistance of heat, and is precipi-
tated from it by water, if the solution be sutiicienrly satu-

quantiryj the series of capacities will be in arithmetical progression, and
th« half sum of any two terms equidistant from the same middle (degree
or) term will be equal ; and the result might therefore be mistaken to
indicate an equality of the capacities. N.

rated

204 0N VARIOUS SPECIES OF CINCHONA.

rated. Water itself redissolves this substance, though it has
been separated from it by evaporation ; but it requires a larger
quantity, than when it is accompanied with the other princi-
ples of cinchona, which seems to show, that these principles
promote the solution in water.
This not ran. If the infusions of. bark be allowed to cool several times,
t\Teu fW j "n before tney are evaporated to dryness, at each cooling they let
fall a matter similar to that just mentioned. It was formerly
supposed, that this substance was rendered insoluble by con-
biningwitb oxigen, but the effect appears rather to be owing
to the insufficiency of the water.
In this the bit- It is this sort of resinous matter, that gives to bark and its
' emess resi | ■ * infusions their bitter taste : for if these sediments be separated
as they form, and the infusion thus boiled down be afterward
made up to its former quantity by the addition of water, it
will no longer possess the same degree of bitterness. The
■uhole"of this matter however cannot thus be separated from
water; for the other principles of the cinchona always retain
a pretty large quantity in solution.
Itisbestpreci- But if, after having proceeded as I have just mentioned,
cohol a" ^e in*usi°ns °f cinchona reduced to the state of soft extract
be treated with alcohol, the greater part of the resiniform mat-
ter will be separated ; and nothing will remain but a brown
viscous substance, that has scarcely any bitterness, is per-
fectly soluble in water, and does not precipitate from it on
cooling.
Two different These experiments teach us, that in the infusions of these
principles m Specics 0f cinchona there are at least two very distinct sub-
stances: *one bitter and astringent, soluble in alcohol, and
but little soluble in water; the other on the contrary wholly
insoluble in alcohol, very soluble in water, and having a
sweet and mucilaginous taste,
in which most These substances being unquestionably those, which ope-
of Us virtue rate m0st efficaciously in the diseases in which cinchona is
employed, I conceive it will not be superfluous to give an
account of their properties somewhat more at large. I shall
Properties of begin with that which is soluble in alcohol. 1. This sub-
that which is stance, in the dry state, has a brown red colour, and a very
hQjU " bitter taste. 2. Cold water dissolves only one portion of it,

another

ON VARIOUS SPECIES OF CINCHONA. 205

another remaining in a flocculent form and of a reddish co-
lour : but if the mixture be heated, this dissolves too, and the
result is a clear liquor, of a very deep red, which grows turbid
on cooling, but lets fall very little sediment.

What is remarkable in the manner in which this substance Singular effect
comports itself with water is, that, if we employ but a small of wateronit'
quantity of this fluid, it dissolves entirely, and produces a
clear liquor : if after this more water be added, it grows tur-
bid; and again it becomes clear on the addition of a still
greater quantity of this fluid.

It would seem from this, that there is spme other sub- Apparently

stance present with it, which promotes its solution when con- °^m& to some

- ' ' *•■'*. • other pnnci-

centrated, and loses this property by being diluted in water, pie.

This is the matter, that renders the decoction or infusion of Erroneously
cinchona turbid, by separating as it cools ; as it does the caUed resin.'
water in which it is macerated, if this be evaporated to a cer-
tain point. It is the same as has been called in pharmacy
resin of bark : but its solution in water grows mouldy in a few
days, and produces fungi, like a solution of gum ; which
proves it not to be a true resin, for it is well known, that
resins never grow mouldy.

The aqueous solution of this substance, recently prepared, Its aqueous so-

and in a somewhat concentrated state, produced the follow- milie&

ing effects with the different reagents I shall mention. 1.

With ammonia it coagulated into a whitish, thick matter, with ammonia,

which grew brown in the open air, and hardened considerably

a little while after: but it softens by heat, and assumes the

ductility and silky lustre of turpentine when kneaded between

the hands.

'*Z. It produced nearly the same appearances with the alka- alkaline car-
... bonates.

line carbonates.

3. The common acids produced no sensible change in it. acids>
Oxigenized muriatic acid turned it yellow, without pro-
ducing any precipitation; but if ammonia were then added,

a light, flocculent, grayish white precipitate was formed.-

4. The solution of animal gelatine does not precipitate it: gelatme>
yet the infusion of these species of cinchona precipitates the
solution of animal &l tie; the principle that produces this ef-
fect therefore must be altered during the evaporation. s

5. The

g06 °N VARIOUS SPECIES OF CINCHONA.

chaly beates, 5. The muriate of iron, or any other ferruginous salt, pro-
duces in it a deep green colour, and soon after a precipitate
of the same tint.

emetic tartar, fj. The antimoniated tartrite of potash occasions no preci-
pitation in it. This substance therefore is not the same as
that, which in the infusions of certain species of cinchona
precipitates this metallic salt.

and litmus. 7. Lastly it very perceptibly reddens infusion of litmus.

Scarcely solu- The acidity of this substance, and the precipitation occa-

ble in water sionocl by alkalis in its concentrated solution, led me to sus-

freed from J . . 7

ackrj ' pect, that its solubility was in part owing to the presence of

the free acid that accompanies it: and this appeared to me to
be confirmed by the circumstance, that, when once separated
by an alkali, washed, and dried, it was no longer soluble in
water but in an infinitely small proportion,
unless an acid To acquire.a greater degree of certainty upon this subject,
theVater*0 * Put some *nt0 water acidulated with various acids; and I
found in fact, that it dissolved in them readily, and that its
solutions resumed a bitter taste, similar to that it had before
it was precipitated by an alkali.
Seems to retain I remarked, that this substance, when precipitated, re-
some of the al- tajneci a part 0f (ne alkali employed to throw it down: at
kah that threw r . r . . .

it down. least the following experiment seemed to prove this. After

its solution had been precipitated by ammonia, and washed in
a large quantity of water, I mixed with it caustic potash,
which immediately produced a very evident smell of ammo-
nia; and this was not, the case, before it had been precipitated
by that alkali.

It is evident therefore, that this substance combines with a
portion of the ammonia, which is employed to precipitate it
from its solution; unless the acid, which naturally accompa-
nies it, forms with this alkali an insoluble salt, tnat mixes
with the resinous mutter, a circumstance that appears not
very probable.
Neutralizes I* seems from these properties, that this substance acts the

both acids and part sometimes ot an acid, at others of an alkali, since it
combines with both these, and in part neutralizes their pro-
perties.
Soluble in ex- If, after having precipitated this matter by alkalis, an excess
cess of alkali. 0f

ON VARIOUS SPECIES OP CINCHONA. £07

of these reagents be added, it is redissolved, and the solution

has a brown red colour.

The solubility of this substance in alcohol is singularly in- Heatgr«atly

creased by heat. When the menstruum is saturated with it, Jnf ceases its so.

i . i . • ,ir lubility in al-

lt has a red colour, and an extremely bitter taste. Water cohol.

throws clown from it a copious precipitate of a fine red slightly

inclining to rose-colour. The alcoholic solution, exposed

to the air in an open vessel, crystallizes in a needly form like

a salt.

The alcoholic solution precipitated by water still retains a Tincture precl-
portion of this substance, which continues to give it a rose- Pltatedby wa*
colour inclining to deep orange [nacarat], and a perceptibly
bitter taste. It deposits this in scales of a brown red by spon-
taneous evaporation.

That principle of the cinchona, which is insoluble in alco- Principle inso-
hoi, being dissolved in water, filtered, and left to spontaneous jubleinako-
evaporation in a warm place, thickens like a kind of sirup,
and crystallizes in laminae, sometimes hexaedral, at others Yields a sak.
rhoniboidal, at others square, and slightly tinged with a red-
dish brown. A portion of a thick fluid always remains, which
never crystallizes completely, and which must be separated
by decantation.

By repeated solution and crystallization this salt may be Which may be
obtained white and pure. Of its properties I shall speak purified.
hereafter. As to the matter that does not crystallize, but re- The remainder
mains in the form of a mother water, it exhibited all the mucilaginous,
characters of a mucilaginous matter, still retaining a small
portion of the salt I have just mentioned, which it is impossi-
ble to separate from it entirely by crystallization.

Action of acids on the rcsiduums of cinchona exhausted by water.

The barks in question, after being exhausted by water, Action of acid*
and even by alcohol, still yield something to acids. They all af:er w*ter,
act nearly in the same manner: that is to say, their effect is
confined to simple solution, without occasioning any per*
ceptibie change in the nature of the principles of the cin-
chona.

I must observe however, that, if the bark have been reduced Dissolve the

to fine powder, aud subjected to the repeated action of a part soluble in

, alcohol,

large

208 0N VARIOUS SPLCIES OF CINCHONA.

. large quantity of alcohol assisted by heat, little is left to hv
done by the acids. The matter taken from the bark by acids
is acccording t*> all appearance the same, as that which dis-
solves in alcohol, as I shall show farther on.
Nitric acuK Nitric acid acquires from it a red, inclining to rose-colour,

and sometimes to a deep orange [nacarat] : but these tints
vary greatly in their intensity according to the strength of the
acid; the stronger this is, the more they incline to yellow.
The nitric acid Jose$,much of its acidity by this combination,
at least as far as we can judge from the taste: it is true it
dissolves at the same time ft certain quantity of lime, which is
detected by oxalate of ammonia, and this contributes to its
neutralization.
Action of car- If saturated carbonate of potash be p'oured into this nitric
soluaon°n the sollltion» a flnc mJ precipitate is formed : but if the common
carbonate be employed, and added in excess, the colour of
the precipitate becomes violet, purple, or blue. Thus alkalis
have the property of blueing that colour of these barks, which
is naturally red.
and of solu- Metallic solutions likewise form in it precipitates of various

ttons of metals, colours, and more or less abundant, according as the nitric
acid contains more or less vegetable matter: but, if the ex-
cess of acid be saturated, the metallic salts then produce in it
ver) copious precipitates, and the liquor is deprived of colour.
• 1. Solution of muriate of tin produces in it a rose-coloured
or carnation precipitate.

2. That of sulphate of iron, a grayish precipitate.

3. That of copper a chesnut brown.

4. Sulphate of titanium, assisted with a little carbonate of
soda, formed with the nitric solution of cinchona an orange
red precipitate, pretty analogous in colour to that produced
by solutions of this metal with galls.

5. Alum occasioned no change in the acid solution of cin-
chona : but aided by a little alkali it carries down with it the
colouring part, and the liquor is rendered colourless.

Might be em- In the countries where these cinchonas grow, a very fine

ployed as a ancj permanent chesnut red for wool and cotton might be ob-
dye. r °

tained from their bark. Soap turns it to a rose colour.

Sulphuric and The sulphuric and muriatic acids, diluted with water, and
muriatic acids. . p0UIC{]

OS VARIOUS SPECIES OF CINCHONA. 209

poured on the residuums of" these cinchonas, dissolve the re-
siniform substance, and saturate themselves with it like the
nitric acid. The colour they thus acquire inclines less to
yellow than that of the nitric acid: it is always of a more de-
cided red.

The precipitates formed in these solutions by alkaline car- Action of car-
bonutes are likewise of a purer red ; and an excess of these al- bonates on
iv . • i •• i * li these solu-

xaline sails gives the precipitate a more evident blue. tions.

The residuums of the cinchonas appear to contain a large Lime in the
quantity of lime : at least a great deal of sulphate of lime is re:>lduums-
produced by spontaneous evaporation in the sulphuric acid in
which they have been macerated.

From the action of acids on the resiniform matter of these Remarks on

c •" i •/ >fJ i l i . c'-i i i tr»e action of

species of cinchona, if it snould at any future time be demon- acid3<

strated, that this substance is the only febrifuge principle in
them, it is evident, that the art of physic may derive from
these barks much more advantage in the cure of intermittent
and low fevers, by adding to them acids or wine. In fact, as
has been seen above, water extracts from cinchona, particu-
larly when it is merely bruised, but a very small quantity of
resiniform matter, and even the greater part of this is precipi-
tated by cooling. Now by this means it is certain, that from
a large quantity of cinchona we extract but a very small part
of the febrifuge principle*; which too, being diffused through
a large body of water, unquestionably cannot produce ail the
effect, of which it would be capable in a more concentrated
state.

It has long been known, that the effect of the essential salt II* €ssentl£d

suit,
of cinchona in fever is by no means proportional to that of

the quantity of bark from which it has been extracted : which
proves, that something useful in the cure of this disease is
left in the magma.

According to my way of thinking, the method hitherto pur- Hith^ta ex-
sued for preparing the essential salt of bark is the reverse of ^d process-
what it ought to be. When an infusion of cinchona is made,

* Mr. Vauquelin has forgotten hi-; if, in the first sentence of this pa-
ragraph. U has not yet been proved, that this is the febrifuge principle :
and indeed he himself had before ranked the principle soluble In water
■with it in this respect. Tr.

Vol. XIX— March, 1803. P it

£10 0N VARIOUS SPECIES OP CINCHONA.

it is evaporated to n certain point, left to grow cool that it
may deposit a sediment, this resiniform sediment is separated
from the liquor, and the evaporation and refrigeration are re-
peated, till the liquor no longer becomes turbid, and has only
a pale yellow colour. It is then dried on plates by the heat
of a stove. By operating thus a very small quantity of re-
siniform matter only remains in the water, with a gum, and a
salt with a calcareous basis, the efficacy of which in the cure
of fever is very questionable.

Co?vparativc examination of the resin of these cinchonas iciih
other known vegetable substances.

jg the matter Is tqere in the vegetable kingdom any immediate principle,
soluble in alco- with which this can be classed? Is it to be placed among
the resins, as has hitherto been done? It is true that chemists
and apothecaries formerly arranged together so many sub-
stances under this genus, that, if we looked to some of its
properties only, we might also rank this among them: but if
we apply the name of resin only to those substances, which
are absolutely entitled to it, those of cinchona and many
other vegetables must be separated from the resins properly so
called.
^0. If the resiniform matter of these cinchonas resemble resins

by its solubility in alcohol, it differs from them by its solubi-
lity in water, acids, and alkalis, and particularly by its pro-
perty of precipitating metallic salts, and fixing in cloth. I
but a peculiar believe then it maybe considered as a peculiar vegetable
principle. principle, the properties of which have not hitherto been well

understood by chemists. This principle is not the same in
every species of cinchona : it differs in those that precipitate
infusion of tan and tartarised antimony, and in those that pre-
cipitate isinglass only.
Perhaos simi- It is probably a principle extremely analogus to it, that

lar to v.hat most commonly imparts a bitter taste to vegetables .

gives bitter- .

ness.

Recapitulation of the properties of cinchonas.

General pro- 1. The different species of bark may be divided into three

hTk*3 °[ classes with respect to their chemical properties.

In

ON VARIOUS SPECIES OF CINCHONA. 21 1

In the first may be comprise:! those, that precipitate tan- Tfh^ dasses
nin, and do not precipitate animal glue.

In the second, those that precipitate animal glue, and do
not precipitate tannin.

In the third, those that precipitate both tannin and animal
glue, and also tartarised antimony.

2. (Ve may conjecture with sufficient probability, that Indication of
every vegetable substance, which does not possess at least one febnfuge pro-
of the properties above mentioned, will not be a febrifuge;

and it is probable too, that the more these properties unite in
a cinchona, or in any other substance, the more striking will
be its febrifuge effects.

3. The property of precipitating tannin not being com-
mon to all the cinchonas, it is not from this exclusively, that
they derive their febrifuge virtue; for there are several that
do not precipitate it, and yet cure intermittent fevers.

4. It appears however, that the principle which precipi-
tates infusion of oak bark and nutgalls is febrifuge, for the spe-
cies that produce this effect are generally allowed to be the
best for medicinal use.

5. On the other hand, since cinchonas which precipitate These not con-
• i • r ■ <> lii c » c , fined to one

neither infusion of tan nor nutgalls are febrifuge, we must principle.

conclude, that the principle, by which these precipitations
are produced, is not the only one in cinchona, that cures
fever.

6. The principle that precipitates infusion of - tan and Principle that
nutgalls has a brown colour, and a bitter taste; it is less so- tar^

luble- in water -than in alcohol; it precipitates likewise tar-
tarised antimony, but not isinglass. It has some analogy
with resinous substances, though it affords ammonia by dis-
tillation.

7. It is apparently with the tannin of oak bark and nut- Doubts,
galls, that this principle combines to form the. precipitates it
occasions in the infusions of these substances: yet, as this
principle exists in some species of cinchona, that precipitate
isinglass at the same time, it remains questionable, whether it
actually combine with the tannin of the infusion of oak bark,

or whether the principle, that in other species of cinchona
precipitates isinglass, be real tannin.

P 2 ft. But

212 OH VARIOUS SVECIF.S OF CINCHONA.

8. But one or the other of these suppositions must neces-
sarily be true, since the infusions of these two sorts of cin-
chona mutually precipitate each other.
Principle that 9. The principle, which in some species of cinchona pre-
Sntine."* "^ c*P*tates isinglass, has a bitter and astringent taste : it is more
soluble in water than thatj' which in other species precipitates
infusion of tan: it is likewise soluble in alcohol: and it does
not precipitate tartarised antimony.

10. It appears, that the substance which precipitates infu-
sion of tan is the same, as that which decomposes antimoniated
tartrite of potash.
Knowlcge of We see from all these doubts, that much remains yet to be
principle a*de- ^ofl*» before we shall attain an accurate knowledge of the.
sideratum. principle or principles in cinchona, from which it derives its
efficacy in the cure of fevers. It is to be hoped, that time
and assiduity will accomplish the solution of this important
question.

Analysis of the salt of cinchona.

Salt of cinch*. Mr. Deschamps, jun., a druggist at Lyons, is the first to
my knowledge, who announced the presence of a peculiar salt
in cinchona, which must not be confounded with the essential
sflll of la Garaye, for this contains at the same time both resin
and mucilage: but as Mr. Deschamps has described only
some of the physical properties of this salt, I thought it neces-
sary to analyse it, in order to discover the nature and pro-
portions of its principles. I have already said how this salt
may be obtained and purified : here therefore I shall confine
myself to an account of its properties.

Its characters. 1. This salt is white; crystallizes in square laminae, which
are sometimes rhomboidal, or truncated at their solid angles;
and these lamina? frequently unite in clusters.

2. It has scarcely any taste, and is flexible between the
teeth.

3. It requires about five parts of water at 10° [50° F.] for
its solution.

4. On burning coals it swells up like tartar, and emits a
- imilar smell ; and leaves a grayish substance, which dissolves

ON VARIOUS SPECIES OF CINCHONA. £ K>

in acids with effervescence, and is nothing but a mixture <•
carbonate of time and charcoal.

0« Its solution does not alter the colour of litmus. In al-
cohol it is completely insoluble.

0. The fixed alkalis, whether caustic or carbonated, de-
compose it. and precipitate lime from it, either pure or in
the state of carbonate.

7. It is not decomposed by ammonia ; which proves, that
its acid has a stronger affinity for lime.

8. Both sulphuric and oxalic acids form a precipitate in its
solution, if it be in a tolerably concentrated state ; the result
being sulphate or oxalate of lime.

9. It produces no apparent alteration in solution of ace-
tate of lead, or of nitrate of silver.

10. Concentrated sulphuric acid, poured on this salt re-
duced to powder, blackens it slightly; but it does not emit
any of the pungent vapour evolved from acetates.

11. A remarkable circumstance is, that the infusion of
tan, and of some species of cinchoua, that of Santa Fe for
instance, occasions a yeiiow flocculent precipitate in the so-
lution of this salt.

The various phenomena produced by these experiments \ compound

indicating, that this salt consisted of a vegetable acid and oflime aud
_. ■ , 111 -i some acid.

lime, in order to decompose it, and obtain the acid separate,

I employed oxalic acid, which is well known to render lime
most insoluble by combining with it. With this view I pro-
ceeded in the following manner.

I dissolved 100 parts of this salt in as much water as was Analysis of it.
requisite. Into this solution I poured a solution of oxalic
acid, from a quantity of a known weight, at different t;nes,
till no precipitate was formed. About twenty-two parts were
necessary, to precipitate the whole of tiie lime, yet I obtained
but twenty-seven parts of dry precipitate.

This proves, that the oxaiic acid employed retained about
half its weight of water of crystallization; and that the salt
of cinchona contained but a small quantity of lime, lor in
twenty-seven parts of oxalate of lime there are but fifteen of
this earth at most.

After having thus separated the lime from this salt by
means of oxalic acid, I allowed the supernatant liquor to

evaporate

£14 ON VARIOUS SPECIES OF CINCHONA.

evaporate spontaneously ; and it was thus reduced to the
The acid erys- sfate 0f a very thick sirup, without affording anv sian of
talhzed sud- ,,••',- • i i i i i " •• , •

denly on agi- crystallization, atter it had stood above a week. Having

tation. stirred it however with a piece of glass, in order to take out a

portion which I intended for another experiment, I was sur-
prised to find the fluid crystallized a few instants after into
a hard mass, formed of a great quantity of lamina*, diverg-
ing from several very distinct centres of crystallization.

It was slightly tinged of a brown colour: its taste was ex-
tremely acid and a little bitter, because the salt of cinchona
I had employed had not been perfectly purified.

I shall now proceed to the properties I ohserved in this
acid, on which however I cannot enlarge very minutely, as
I had but a moderate quantity of the salt at my disposal. I
believe however, that I have examined it sufficiently, to be
convinced of its being a peculiar acid hitherto unknown.

Its properties. In its state of crystallization it has a very acid taste, and is
a little bitter*, as I have said above.

It keeps perfectly well in the open air, being neither deli-
quescent nor efflorescent*

On burning coals it melts very quickly, boils, grows black,
emits pungent white vapours, and leaves but a very light
coally residuum.

With the earths and alkalis it forms soluble and crystal-
lizable salts.

It does not precipitate nitrate of silver, mercury, or lead,
as most other vegetable acids do.

It is s new ve- There appears no doubt, that this acid is new to us; for,

differing from on reviewin°' the characters, of all the other vegetable acids
known, neither of them unites in it all the properties of this.

the oxalic, Jn fact oxalic acid forms an insoluble salt with lime, and

besides decomposes the compound formed of this earth and
acid of cinchona.

citric, and tar- The citric and tartarous acids form likewise insoluble salts
with lime, and decompose acetate of lead.

malic, The malic acid- does not crystallize, and precipitates ace-

tate of lead.

* Mr. Vauquelin has just beon ascribing this bitterness to the im-
purity of the salt he employed, consequently iti> not a character of Lhe
afcid. Tr.'

The

\

ON VARIOUS SPECIES OF CINCHONA. 0]5

The benzoic acid is but little soluble in cold water, and is benzoic,
volatilized without being decomposed.

The o-allic acid too is but little soluble in cold water, and gallic,

o

blackens solution of iron.

It is analogous to the acetous acid in the solubility of its acetous,
combinations; but the acetous acid does not crystallize, and
is volatilized without alteration. ,

I say nothing of the camphoric, suberic, or succinic acids, and others,
for they bear no analogy to it.

Let us then conclude, that this acid is really different from The kink acid
all those hitherto known, and give it the name of Jcznic acid,
from the word quinquina, ti&U becoming more ultimately
acquainted with its nature and combination, we can frame a
better.

It is to this acid united with lime, according to the report combined with

of Mr. Deschamps, that the physicians of Lyons ascribe the li1me :.s*id ,to be

r l J - . , the febrifuge

febrifuge virtue of cinchona. They assert, that no intermit- substance.

tent fever can resist two doses of this salt of thirty-six grains
each.

If this assertion. were proved, we might pretty easily con-
ceive how a drachm of this salt cures an intermittent fever,
for this quantity is as much as can be obtained from at least
live or six ounces of common gray bark.

I cannot directly contradict this result, announced by per- This question-
sons of credibility and well informed ; yet I think 1 have suf- a e»
ficient reason, to entertain some doubts of its accuracy. In for different
the first place, before it can deserve complete confidence, it reasons.
must have been tried a great number of times, and with uni-
form success: for it too often happens, that effects are ascribed
to medicines, which in fact are owing entirely to nature. In
the art of physic, more than in any other branch of natural
philosophy, causes are so complicated, that it is difficult to
trace with certainty what belongs properly to each.

On the other hand physicians have learned by long expe-
rience, that the infusions and extract of bark prepared after
the manner of la Garaye are far from producing equal ef-
fects in fever with the quantity of bark from which they are
prepared, if this were administered in its natural state : yet
these preparations contain the salt in question.

It is known too, that spirituous tinctures of bark, in

which

2 \6 ON THE QUANTITY OF CARBON IN CARBONIC ACID.

in which the salt of Mr. Deschamps does not exist, since
it is insoluble in such menstruunis, cure intermittent fe-
vers.

Besides, there are cinchonas, which contain but extremely
small quantities of this salt, and vegetables in which none
of it is found, that likewise cure fevers. Tt is not then
without reason, as is obvious, that I express my doubts on
this head: and if it have sometimes happened, that this salt
has cured fever, we may suspect, that it had not been perfectly
freed from the bitter principle, which it strongly retains.
Desirable that It is desirable however, that this question should be re-
b SJl()U(jd be solved by experiment as soon as possible: for, if the results
of experience be conformable to those of the physicians of
Lyons, it would certainly be a very useful discovery for man-
kind.

VIII.

On the Quantity of Carbon in Carbonic Acid, and on the
Nature of the Diamond, By William Allen, Esq.
F.L.S. and William Hasledine Pepys, Esq. Com-
municated by Humphry Davy, Esq., Secretary R. S.
M. R. I. A*

Quantity of JL HE estimates of the quantity of real carbon in carbo-

carbonmcar- bonjc acjd differing very widely, and the experiments of

bonic acid not _ _ __ & , * , • c . v i

ascertained Guytpn de Morveau upon the combustion or the diamond,

and experi- detailed in the 3 1st volume of the Annales de Chbnie, being
ments on the .... , . n ,, • , . , .,,

diamond ob- liable to some objections, from the manner in which the

jectionable. operations were conducted ; we determined to institute a
set of experiments, in order, if possible, to settle the ques-
tion.

Lavoisier, from the result of experiments apparently con-
ducted with much accuracy, concluded, that every hundred
parts by weight of carbonic acid consisted of 28 carbon and
72 oxigen. This was in a, great degree confirmed by the

♦ Philos. Trans, for 1^07, Part II, p. 267.

very

ON THE QUANTITY OV CAR50N IN CARBONIC ACID* 217

very valuable researches of Smithson Tennant, Esq., on the
nature of the diamond, an account of which is printed in
the Transactions of tins Society for the year 1797, and which
were made previously to the experiments of Guyton ; but
notwithstanding this, the result of Guyton's experiment,
which only allowed i7*88 per cent of carbon to carbonic
acid, has been adopted in all the systems of chemistry to
the present time.

In researches of this nature, the results are much in-
fluenced by slight variations* in the quality of the gas; but
having- had repeated experience of the accuracy of the eudi-
ometer described in No. XII, of this volume*, we were en-
abled to proceed in this respect with great confidence.

Our object was, to consume certain known quantities of Attempt to at.
diamond and other carbonaceous substances in oxigen gas, certain the
and we at first determined to employ the sun's rays, by means
of a powerful lens ; but considering the uncertainty of a
favourable opportunity in this country, and at the season in
which our experiments were made, we resolved to employ
the apparatus respresented by the drawing.

Description of the apparatus.

This consisted of two mercurial gasometers, PI. VI, fig. Apparatus de-
1 and 2, each capable of containing from 70 to 80 cubic scnbed«
inches of gas. The internal cylinder C C is of cast iron,
and solid, except the perforation through its middle; the ex-
ternal cylinder is also of cast iron ; and the glass receiver
slides up and down in the space between them, which is
tilled with mercury: not more than 16 pounds are required
for each, and the small bath B, fig. 1.

To the top of each receiver a graduated scale or register,
H, is screwed, showing the number of cubic inches of gas,
measuring from the upper edge of the external iron cylinder.
The level of the mercury is ascertained by a small glass
gauge. The registers were graduated by throwing up one
cubic inch of gas at a time.

The gasometers stand upon mahogany stools, perforated
for a socket, to which, according to the nature of the ex; e-

* See our last Number, page 86.

riment,

£]£ ON THE QUANTITY OF CAllBON IN CARBONIC ACID.

riment, a small receiver R, or the triple socket T S, or any-
other combination, may be united.

V represents the platina tube with its furnace ; the ends
of the tube are mounted with female screws of brass, to one
Of which the accommodating screw socket AS was joined.

T is a double section of the platina tray, which contained
the substances to be heated. During their combustion, it was
made to slide easily within the platina tube P. The accom-
modating socket and platina tray are drawn considerably
larger in proportion than the instrument.

By means of the triple socket and the cocks, the gas was
made to pass freely over the substances in combustion, from
one gasometer to the other ; and by shutting off the commu-
nication with the platina tube, while that with the small re-
ceiver was open, any portion of gas in the gasometer, fig. 1,
might be transferred into eudiometers or measures standing
in the mercury bath M, for examination.

In order to discover whether the several sockets were air-
tight, after the apparatus was put together, the communica-
tion with the gasometer, fig. 1, was closed, and the other
communications opened; the receiver of the gasometer, fig.
2, being raised, drew up a column of mercury in the small
receiver R, equal to 2 inches: the communication with the
gasometer was then closed, and the column was supported
■without alteration. This was always tried previous to, and
after every experiment. As the joints would bear this degree
of exhaustion, we were confident they would resist a much
greater pressure than we had any occasion to employ. The
glass tubes G G, which connected the platina tube with the
gasometers, enabled us to observe any flash arising from the
combustion of hidrogen which might be contained in the
substances subjected to experiment. In order to avoid prolix-
ity, we shall generally state the method which was invariably
followed.
Oxigen gas in- We soon found that oxigen gas, even when secured in
jured by keep- bottles with ground glass stoppers, was not always to be de-
pended upon, but was sensibly deteriorated by keeping; and
therefore in all our experiments we made the gas within an
hour or two of the time of using it, and always from the hy-
Manner in peroxigenised muriate of potash. Its degree of purity was

constantly

ON THI QUANTITY OF CARBON IN CARBONIC ACIIT. 219

constantly ascertained by the eudiometer before every expe- whioh its puri-
, ;, , , • . , • ty wasascci-

nrnont, and was generally determined in about 10 minutes. tained.
The solution employed was that recotnmendt d by Professor
Davy ; namely, the solution of green sulphate of iron satu-
rated with nitrous gas*; and whenever the diminution had
arrived at its maximum, and the gas began to increase in
volume, we substituted a. simple solution ofj the green sul-
phate of iron for that saturated with nitrous gas, and always
had the most satisfactory results : for the simple sulphate
absorbs any nitrous gas which may have escaped from the
saturated solution, and the residuum in this case enables us
to ascertain exactly the quantity of oxigen contained in the
gas.

We determined to make our first experiment with char- Woods char
coal, and as Morozzo and Rouppe had ascertained the ab- re '
sorbing properties of this substance, and as our results must
obviously be influenced by it, our attention was directed to
this point. The following quantities of different kinds of
wood, sawed into slips -tV of an inch were weighed.

White Fir 300 grains ° Their weight.

Lignum Vitas 800

Box • 400

Beech • • • • 500

English Oak 250 .

Mahogany ...... o(,o

These slips were put into small crucibles, and completely jn sman cruci_
covered with dry sand. Heat was very gradually applied at ble* u»der dry
first, until the volatile parts were dissipated ; they were then
kept about 40 minutes iu a white heat. On being collected
and weighed, while still warm, the charcoal from each was as
follows :

fir 51*5 grs, equal to 18-17 per cent. Weight of

Lignum Yitae 138 17-35 . duced** ^°"

Box 81 20-25

Beech • 75 15

Oak 43-5 17'40

Mahogany. 31'5 ••• 1575

* Tnis solution absorbs oxigen much more rapidly in warm weather
than in cold.

These

*20

Gain by a
week's expo-
sure to air.

This probably
by absorption
of water.

"Experiment
with willow
charcoal.

ON THE QUANTIFY OF CARBOtflN CARBONIC ACID.

These being exposed to the air during one week, increased
in weight thus :

Fir 13 per cent.

Lignum Vita • • 0/6

Box 14

Beech l6*3

Oak 16-5

Mahogany .... 18

Certain quantities being confined in common air increased
very little in weight, and all in the same proportion ; we are
therefore much inclined to think, that this increase is owing
to an absorption of water from the air ; and we repeatedly
found, that the greatest increase of weight took place in the
first hour or two after exposure, and arrived at its maximum
in less than 24 hours, as the following experiment, selected
from several others, will prove.

Forty grains of charcoal from willow wood, which had
been put into a bottle with a ground glass stopper immedi*-
ateltf after they were removed from the fire, were exposed in
the scale of a delicate balance, in a room where the thermo-
meter was 62° Fahrenheit, barometer 30*26.

Grains. Total Increase. Time.

6 o'clock P. M. 40

\ past 407 + *7

7 41*3 + •<> = 1*3 1 hour.

I past 41*6 + '3 ~ V6 If hour.

8 41*8 + -2 = 1*8 2 hours.

The pieces were now spread out on paper after every weigh-
ing, to expose them more completely.

£ past 8 42-5 -f 7 = 25 2f hours.

9 42*8 + "3 n 2*8 3 hours.

§ past • 43.1 + '3 ' — 3-1 3j hours.

10 43-3 -f -2 c 3*3 4 hours.

\ past 43*4 + -1 SE 3-4 4| hours.

Here it was left all night.

10 A. M. 45 +1*6 =: 5 lG hours.

4 P.M. 45

6 P.M.

ON THE QUANTITY OF CARBON IN CARBONIC ACID. 221

Grains. Total increase. Time.

6 P.M. 44*5 — '5 38 4*5 24 hours.

9 44*4 — '1 zz 4*4 27 hours.

Next day.

f past 8 A.M. 44*9 + '5 = 4*9 38f houfs.

f past 1 P.M. 447 ~ *2 is 4*7 43 § hours.

10 .•••• 44*5 — *2 = 4*5 52 hours.

Hence charcoal seems to act as an hygrometer: its greatest Seems to acta*
increase was 5 grains on 40, or 12f per cent. And in order anhygromeier*
to ascertain to what the increase of weight was owing, we
put 27*25 grains of charcoal, which had been thus exposed,
into a small bottle and tube connected with a receiver stand-
ing in the mercury bath, the whole of the vessels being also Water expel-
filled with mercury, in order to exclude common air. Heat
applied by an Argand's lamp produced gas equal to about
half the bulk of the charcoal; but as soon as the temperature
of the mercury rose to 214° Fahrenheit, elastic fluid stream-
ed from every piece of charcoal, which quickly condensed,
and 1± inch of the tube was occupied with water. This
proved that our suspicion of the increase of weight being
principally attributable to water, was well founded.

The result of these, and other experiments, plainly point- Hence certain
ed out the precautions which were necessary, in order to ob- nece^sarr*18
tain an accurate result with charcoal; for if we had weighed
4 grains of the charcoal a few hours after it was made, we
should only in fact have had 3 '5 grains of real charcoal, and
our calculations would have been erroneous. To avoid this
source of errour, we subjected our charcoal to a red heat im-
mediately before using it, and also weighed it as speedily as
possible; in fact, while it was still warm. It may be proper
to state, that our weights were such as we could thoroughly
depend upou.

The volume of gas being so much influenced by tempera- The volumeof
ture and pressure, these were noted during every experiment ; fenced by *
and thermometer Go0 Fahrenheit, barometer 30°, were as- temperature
sumed as the standard. Gay Lussac remarks, that from an ?ressure-
32° to 212° Fahrenheit, dry air expands 0-00209, Or ^
part of its bulk for every degree of the thermometer. Dal-
ton makes it 0*00207, or 4-|T part; we therefore divided

the

(222 oN THE QUANTITY OF CARBON IN CARBONIC ACID.

the whole quantity of gas by 480, and multiplied the quotient
by the degrees of difference under GO°.

It being- of great consequence in these experiments to
Sp. grav. of ox- know the exact weight of a given quantity of oxigen and car-
mc^arid "asses Domc llCK^ gasses, we resolved to examine for ourselves,
determined. whether the statements aheady given were quite correct, and
accordingly made carbonic acid over mercury from Carrara
marble and diluted sulphuric acid, which, being tried with
lime water in Pepys's eudiometer, was all absorbed in 3 mi-
nutes, except 1 part in 100. We used two charges of lime
water, though one would have been sufficient.
Carbonic acid A glass globe, being exhausted by an excellent airpump,
was exactly balanced on a beam sensible to a minute portion
of a grain : then being screwed upon one of the glass receivers
of the mercurial gasometer previously filled with carbonic
acid gas, 21 cubic inches entered. The globe was now in-
creased in weight by 10'2 grains, In order to be certain,
We repeated the experiment, with exactly the same results*
The 21 cubic inches were to be brought to the mean tem-
perature and pressure, as the thermometer stood at 44° Fah-
renheit, the barometer *29 '30'.

21 480) 2 1-00(0-043 G0°

-6$ add for temp. 16 44

21-68 0-6S8 add for temp. 16 diff.

Correction for pressure.
30: 29*86:: 21-68 : 21'58

The volume therefore at mean temperature and pressure
would have been 2 1*58, cubic inches.

21-58 : 10*2:: 100:47*26

100 cub. inches Consequently 100 cubic inches of carbonic acid gas at mean

weigh 47-^0 temperature and pressure weigh 47*26 grains.

g's" We next tried oxigen eas from the hyperoxigenised mu-

Oxigon gas. . „ .. , b i i • i i xi ■ i-

riate of potash made over mercury, and which by the eudi-

- ometer left only a residuum of 2 parts in 100. The glasi

globe, exhausted as before, and weighed, was screwed on to

the glass receiver of the mercurial gasometer containing

oxigen, and 21 cubic inches entered,, by which it increased

in

ON TIIF. QUANTITY OF CARBON IN CARBOLIC ACID. 0.0%

ia weight 7*3 grains. This experiment was repeated with
exactly the same result. The thermometer and barometer
remaining the same, we take the volume as before cor*
rected.

21*58 cubic inches.
21*58 :7*3 :: 100:33*83

Then 100 cubic inches of oxigen gas at mean temperature lOOcub.inche*
and pressure weigh 33*82 grains. After these experiments, wei£h^-82
we examined Davy's researches on nitrous oxide, and had
the satisfaction to find, that his estimate, both of carbonic
acid and oxi gen gasses, agreed almost exactly with ours,

The next point was to ascertain whether limewater would Whole of car-
take the whole of the carbonic acid gas from a mixture with ^"^bedV38
oxigen, or common air; we therefore mixed a known quan- common air by
tity of carbonic acid gas with a certain quantity of common UmewateF
air, and on trying it with our eudiometer and limewater, the
whole of the carbonic acid gas was in a short time absorbed,
We also found, that, though the solution of green sulphate
saturated with nitrous gas would not take up the whole of
the carbonic acid gas, yet the simple green sulphate, merely or <*reen rat
by its water of solution, absorbed it very readilv. phateof iron,

Jt may be proper to notice here, that though we repeatedly Gas from hyp,
tried the oxigen procured from hyperoxigenised muriate °f ™ntained°no*
potash by the eudiometer and limewater, it never gave the trace of carbo-
least trace of carbonic acid. nic acid*

Experiment with Charcoal from Box-wood,

The thermometer being at 42° Fahrenheit, barometer at Experiment

30*2, vve kept some box-wood charcoal red hot for a consi- withbox wo°4
■ill- i i i'ii • charcoaj.

derable time under sand, and weighed 4 grains as expedi-
tiously as possible; this, being put into the platina tray, was
pushed to the middle of the platina tube; the oxigen (made
from hyperoxigenised muriate of potash over mercury) was
contained in gasometer No. 1 ; No. 2 was empty, Every-
thing being adjusted and found perfectly air-tight, the com-
munication with the small receiver R was closed, and the
common air contained in the tubes and sockets, amounting
only to 2*84 cubic inches, was driven out by a pressure of
oxigen from gasometer No. I. When several cubic inches

had

224* 0K T1IE QUANTITY OF CARBON IN CARBONIC ACID.

had passed info gasometer No. 2, the gas was let out by
opening the cock at the top of its glass receiver, and pres-
sing it down ; the cock being then closed, the gasometer
No. 2 was completely empty, and the whole of the gas from
No. 1 was driven through the tubes into No. 2, and back
again. The common air having been previously withdrawn
from the small receiver R, we tried the purity of our oxigen
by the eudiometer in the manner before described, and
found a residuum of 3 parts in 100: we then disengaged as
much gas as reduced the quantity to 47 cubic inches by the
register or scale; to this must be added the contents of the
tubes and sockets 2*84 cubic inches, making the total quan-
tity of oxigen employed 49*84 cubic inches.

Correction for temperature.
49*84 480)49'84(0'103 60°

1*85 for temp. 18 42

5 1 69 1 *854 add for temp. 1 8 diff.

Correction for pressure.
30: 30-2:: 51-69 :5203.

The volume, therefore, at mean pressure and temperature,

would have been 52*03 rubic inches.

Burned in the We now lighted a fire in the small black lead furnace

witrTox^een un^er tne platina tube, and, as soon as it became red hot,

gas. opened the cocks, and passed the gas from No. 1 to No. 2,

when the charcoal entered into vivid combustion, and heated

the platina tube white hot. The operation was repeated

many times during 6 or 7 minutes, by pressing alternately

No flash of upon the glasses of the gasometers; Not the least flash of

light or appear- light was observable in the glass connecting tubes GG, nor

anceof BOB- ' ° »'■■>* r™ r 1 •

ture. the smallest appearance 01 moisture. 1 he turnace being

removed, the tube was now cooled by the application of wet
cloths ; and when all was reduced to the temperature of the
room, we pressed upon the glass of gasometer No. 2, so as
to force ail the gas into No. 1 . The cock below being closed,
we tried the tubes, &c. and found them perfectly air-tight.
We next unscrewed the tube and took out the platina tray ;
but it only contained a light white ash, somewhat resembling

the

OK THE QUANTITY OF CARBON IN CARBONIC ACID. OO5

the shape of the pieces of charcoal, and weighing only *02 Left -02 gr. of
of a grain. On observing the register of No. I, it indicated whlte ashes*
exactly the quantity of gas that we began with, so that al- Thevolumcof
though 3*98 grains of charcoal had been dissolved, the vo- gas unaltered*
lurae of gas was unaltered by it; a circumstance which had
been remarked before by Lavoisier. Tke small receiver 11
was now nearly full of mercury ; the communication with
the gasometer being opened, the large glass receiver was gen-
tly pressed upon, until several cubic inches were forced
through the receiver II, and tube K, in order to clear the
latter of common air. This being done, on trying our gas
with the eudiometer and limevvater, 56 parts were absorbed
out of 100. These of course were carbonic acid gas; the test
for oxigen absorbed 4-1, and a residuum of 3 was left, which
was exactly what we began with. This is a striking proof, that Nothing pro-
jiMhing but carbonic acid was produced in the experiment. jjuc?d b?j car"

.100: 56:: 52-03: 29-13.
Then 29*13 cubic inches of carbonic acid gas were produced. 2913 cub.
100 : 47*26 : : 29'13 : 1376\ incbe*»

These 29*13 cubic inches of carbonic acid gas would there- weighing
fore weigh 1376 grains. 13'76 SIS-

The charcoal weighed 4 grains.
The residual white ash 0*02

Charcoal consumed • • 3*98 grains.

Then if 13 76 grains, the weight of the carbonic acid produced,
contain 3*98 of charcoal, 100 grains must contain 28*92.

1376: 3'98:: 100: 28-92.

Then, according to this experiment, 100 grains of carbonic
acid gas contain 28 '92 charcoal.

The gas before the experiment consisted of

Oxigen .50*47 cubic inches.
Azote* • l'5()

u

5203
Voi>. XIX— March, 1808. Q After

236

ON THE QUANTITY OF CARBON IN CARBONIC ACID.

After the experiment,
Carbonic acid '2$' 13 cubic inches.

Oxig.n 21 '34

Azote 1*56

52'03

Now as the volume of gas was unaltered, it will be fair to
consider the quantity of oxigen gas consumed as equal to the
carbonic acid produced, or 29*13 cubic iiieh'cs.
Then, if 100 cubic inches of oxigen weigh 33'82 grains, 29*13
cubic inches will weigh 9<S5 grains.

100: 33*82:: 29*13 :9'85.
77 charcoal. The weight of oxigen consumed was therefore Q'S5 grains.
Charcoal consumed 3'98

100 parts of
carbonic acid
gas by weight
Contain 71-23
oxigen gas

Carbonic acid from this statement

Ditto by calculations on Carb. acidgas 1376

13- S3 grains.

•07

Exp. 1. On
diamond .

3*95 grs Brazil

13*83 :3*9S: : 100:2877.
Thus, calculating by the oxigen consumed, 100 grains of car-
bonic acid gas contain 28*77 charcoal.

First Experiment on Diamond,
Thermometer 5a? Fahrenheit, barometer 30*20.
Our oxigen was made as in the former experiment; it con-
tained no carbonic acid; and, on being tried with the impreg-
nated green sulphate, left a residuum of 3. parts in 100.
Having selected nine of the clearest and. most transparent

diamond bum- Brazil diamonds, we found they weighed 3'9o grains. Theso
real. " wCre r^nSe^ m ^ne Patina tray, which was placed in the tube,

and the whole apparatus, adjusted as before, was perfectly air-
tight. The quantity of oxigen was 4-9*84 cubic inches, as in
the last experiment. The .same precaution.^ were used to se-
cure accuracy in the results as in the former experiment; and
it would only be an unnecessary intrusion on the time of the
Society to repeat them. The platinatubc was heated red hot,
and kept so for ten minutes : during this time the gas .was re-
peatedly

OX THE QUANTITY OF CARBON IS CARBONIC ACID* QOJ

peatedly passed from one gasometer to the other .;• the tube The combus-

did not become white hot, as in tbe experiment with charcoal,

because in this case the combustion went on more slowly.

When every thing was cooled to tlue temperature, of the room,

the gas was'all passed into No. 1, by pressing down the receiver

of No. 2, and the volume was precisely the same as when we

began the experiment. On drawing out the tray, we observed Residuum an

that some of the diamonds were reduced to a minute speck, ename^

and all of them resembled opake white enamel: there was no

discoloration in the tray, nor any residual ash whatever ; the

unconsumed'parts weighed 1*40' grains; the original weight

was 3'Qj • 2-49 gr». con-

,../• sumed.

1*40

consequently 2*49 grains' were consumed,.

i

We could not perceive any dullness on the surface of the mcr- No moisture-
cury in the geometers, or any appearance of moisture. appeared.

On introducing limewater .to. 100 parts of the gas in the
eudiometer^ a dense white precipitate was formed, and 3$
parts absorbed; the test for oxigen absorbed Go, and a.resi- Residual gas
iluum of 4 was left. increased -01.

Correction for temperature.
60° 450)49'S4(0:10:3 4<J\84

56* 4 -41 add for temp.

4 difference ;412 80*36

Correction f6r pressure.
30: 30'20 ;:io*25: 50*58.

The quantity of oxigen at the mean was 50'5S cubic inches.
100 :3<i : : 50*58 : 18 '20 cubic inches.

The quantity of carbonic acid gas produced wasl&*20 cubic 18 2 cub. inch.
i ' carbonic acid

,nchcs- produced, -

100 : 47-26 : : 1S'20 : : 8'GO grains.

8*00: 2-49:: 100 : 28;95. "

Then 100 grains of carbonic acid gas contain 28*95 of dia- containing

mond. "2895 b? wt-

of diamond.

Q 2 Calculation

22S

ON THE QUANTITY OF CARBON IN CARBONIC ACID.

100 : 33S2 : : 18*20 : 6*15 grains of oxigen consumed
2*49 grains of diamond.

8*64
Calculation by carbonic acid 8*60

•04 difference.

or fr«m the
oxigen con

Exp. 2.

4'01 grs. of
diamonds

8-64: 2*49 :: 100:28*81.
Thus, if we calculate upon the oxigen consumed, 100 grains
sumed °288l. °^ carbonic acid gas contain 28'Sl of diamond.

Second Experiment on Diamond,

Thermometer 48° Fahrenheit, barometer 30*08. Oxigen
gas, made as usual, left a residuum of 3 parts in 100.

Eleven small diamonds, weighing 4*01 grains, were put
into the tray. We began with 49*84 cubic inches of oxigen ;
and every thing being properly adjusted, kept the platina
tube red-hot for a quarter of an hour, and during this time
the gas was passed from one gasometer to the other, as in
the former experiments. When the tubes, &c. were cooled
down to the temperature of the room, all the gas was trans-
ferred to gasometer No. 1, and the volume was exactly
the same as before the experiment. On examining the tray,
all the diamonds were entirely confumed and not a vestige
left.

Lime water absorbed 57*5 parts from 100
The test for oxigen 3.9*5
Residuum • • 3

entirely con-
sumed.

100

60e

48

Correction for temperature.

0*103 49*84

12 1*23

Correction for pressure.
30: 3008:: 51*07*51 -CO.

12 diff. 1*236 add for temp. 51*07

The

ON THE QUANTITY OF CARBON IN CARBONIC ACID. ggg

The volume of gas at the mean was therefore 51*20 cubic
inches.

100 : 57'50 : : 51*20 : 29*44.

Then 20*44 cubic inches of carbonic acid gas were produced. Produced

° 2944 cub. in.

100 : 47*26 :: 29*44 : 13*91. of carbonic acid

13*91 :4*01 :: 100:28*82. guS

Then, according: to this experiment, 100 grains of carbonic containing

• , • <J ™ j f -2882 of dia.

acid contain 28*82 diamond. niond ,

Calculation by Oxigen.

100 : 33 '82 : : 29*44 : 9*95 grains of oxigen consumed

4*01 of diamond

13*96
Calculation bv carbonic acid 13*9 1

•05 diff.

13'96:4*01 :: 100 :28*72.

Then, calculating by the weight of oxigen employed, 100 or,fromoxr-
grains of carbonic acid contain 28'72 diamond. g2e8720nSUm

The precipitate in lime water from the gas produced in the Appeared to
combustion of diamond appeared to us denser than that occasion a den-
from the combustion of charcoal. ii/limewater,

In order to see how far the weight of the precipitate of than that from
carbonate of lime would agree with the results of the fore-
going experiments, we drew off 20*5 cubic inches of the gas,
which had been thus altered by the combustion of diamond
in the last experiment, by the register H, and received it in
bottles over mercury ; then admitting lime water, we obtained
a copious precipitate of carbonate of lime, which, being
dried at the temperature of 212° Fahrenheit, weighed 12
grains.

But as the 20*5 cubic inches require the same corrections
to bring them to the mean' temperature and pressure ; we
say, as the actual volume of all the gas is to its correction,
so is the quantity drawn off to that which it would have been
at the mean :

49*84 : 51*20 : : 20*50 : 21-06, the volume after the correc-
tions were made.

Then,

£30 0N TIIE QUANTITY. OF CARBON IN CARBONIC ACID

Then, to find how much carbonic acid was contained in
these 2T06 cubic inches, we state it thus: As the total quan-
tity of gas after the experiment is to the total weight of car-
bonic acid gas found by calculation, so is the quantity of gas
experimented upon to the weight of carbonic acid gas which
it ought to have contained,

51*20 : 13<)1 : : 21*06 : 5*72 grains.

Every 100 grains of precipitated carbonate of lime con-
tain 44 grains of [carbonic acid; 12 grains were procured in
our experiment. 100 : 44 : : 12 : 5*28

The weight of Therefore the carbonic acid contained in our precipitate of
Mwee<nwlTC l* *'6™°* weigned 5*28; by calculation it should have
with the fore- weighed 5*72; this is as near as we had a right to expect
going results. from the difficulty of collecting the precipitate.

Stone Coal.

Experiment Upon the suggestion of our mutual friend Professor Davy,

with Welch we next examined the results of the combustion of stone
stone coal. coaj an(j piumbago ; thermometer 57° Fahrenheit, barome-
ter 29*65.

The stone coal from Wales, employed by maltsters, is well
known to contain little or no maltha, or mineral pitch, and
to burn without flame. .

A portion of this coal was placed under sand in a crucible,
4 grs. charred an(^ exPose(l to a strong heat for one hour ; 4 grains of it thus
and then bum- prepared were put into the tray : our oxigen left a residuum of
5 parts in 100, and we began with 49*84 cubic inches as
usual. The tray being placed in the platina tube was
heated to redness for about 10 minutes. When the gas
was first passed, we thought we saw a flash in the glass
tubes. On suffering the whole to cool, the quantity of gas
still remained the same, and the tray being drawn out con-
tained only *5 of a grain unconsumed. From the gas thus
|gr. residuum, charged with 3*5 grains of coal,

Residual gas Lime water absorbed 53 parts from 100.

increased '03 , The tests for oxigen 39

Residuum 8 or an increase of 3.

100

Cor recti ou

$N THE QUANTITY OF CARBON IN CARBONIC ACID. £3 J

Correction for temperature.

60° 0*103 49.84

57 3 -30

_ ...

3 difV. 0-309 add for temp. 50*14

Correction for pressure,
30:29*65 :: 50'14: 49*55.

The quantity of oxigen at the mean was therefore 49*55 cu-
bic inches.

100:53 :: 49*55 : 26-26.

Consequently 26*26 cubic inches of .carbonic acid gas were 26-26 cubic

produced. inch carbonic

acid gas produ-

100 : 47*26 : : 26*26 : 12*41 grains. ced»

12*41 :3'50 :: 100:28*20.

Then, according to this experiment, 100 grains of carbonic !?8<Simfng i
acid gas contain 28*20 of coal.

Calculation by oxigen.
100 : 33*&2 : : 26*26 : 8*88 grains of oxigen consumed.
3*50 coal

12*38

Calculation by carbonic acid 12*41
by oxigen 12*38

difference -03

Here, contrary to what happened in other experiments, the or,from oxigen
calculation by carbonic acid rather exceeds that by oxigen : -2827.

12*38:3-50 :: 100:28*27.

Calculating therefore by oxigen, 100 grains of carbonic
acid contain 28*27 of coal.

Experiment xcith Plumbago.

Thermometer 44° Fahrenheit, barometer 29*94. Exp. with

Four grains of plumbago, from a very fine specimen be- 4 grs#

longing

S3S

left *2 gr. of
oxide of iron.

Residual gas
increased -01,

ON THE QUANTITY OF CARBON IN CARBONIC ACID.

longing to Dr. Babington, were put into the tray. Our oxi-
gen left a residuum of 2 parts in 100, and we began with
49*84 cubic inches. The tray, with its contents, being
placed in the platina tube, was heated to redness for a quar-
ter of an hour, and the gas made to pass over it several
times. When all was cool, the original quantity was neither
increased nor diminished, and on withdrawing the tray we
found only *2 of a grain of oxide of iron ; so that this spe-
cimen of plumbago contains only 5 per cent oxide of iron.
The gas being now examined,

Lime water absorbed 55 parts from 100

The tests for oxigen 42

Residuum 3or an increase of 1 percent.

x'8 25 cubic
inches of car-
bonic acid gas
produced,
containing
'2846 of car-
ton.

6o°

44°
16 diff.

100

Correction for temperature.
01 03
16*

49*84
1-64

1-648 add for temp. 51*48

Correction for pressure.
30: 29*94:: 51*48: 51*37.
The quantity of oxigen at the mean would be 51*37 cubic
inches.

100:55 :: 51*37: 28*25,

Therefore 28*25 cubic inches of carbonic acid gas were pro-
duced.

100 : 47*26, : ; 28*25 : 13*35 grains.
13-35:3*8 :: 100:28*46.

Then, according to this experiment, 100 grains of carbonic
acid contain 28*46 of the carbonaceous part of the plum-
bago.

Calculation by oxigen.
100 : 33*82 : : 28*25 : 9*55 grains of oxiget*
consumed 3-?o plumbago.

13*35
Calculation by carbonic acid 13.35

First

ON THE QUANTITY OF CARBON IN CARBONIC ACID. £33

First Experiment on animal Charcoal.

Thermometer 60° Fahrenheit, barometer 30*23. Exp. l. On

Muscular fibre distilled in a coated glass retort left a coal"* ° &^
black shining- coal, 4 grains of which were put into the tray. 4grains from
Our oxigen left a residuum of 2 parts in 100. The tray muscular fibre,
and its contents being placed in the platina tube, was heated
to redness for 8 minutes. The first time the gas was Lambent
passed, a lambent flame filled the whole length of the glass
tube, and the gas became turbid or milky. It was passed turbid.
frequently through the heated tube, but we observed no re-
petition of the flashes. Hence we conjecture that if the
diamond had contained hidrogen, we should probably have
had a similar appearance. After the experiment all the ap-
paratus was, as usual, perfectly tight, and the Volume of
gas unaltered. On examining the platina tray a minute Saline matter
portion of charcoal remained, and a quantity of saline mat- efu
ter adhered to it so firmly, that it became difficult to ascer-
tain the quantity of carbon consumed, and we forebore to
make the calculation ; we however examined the gas.

Lime water absorbed 40 parts from 100
The tests for oxigen 54

Residuum ......... 6 or an increaseof 4 per ct. Residua! ^as

increased '04.

100

Second Experiment on animal Charcoal.
Thermometer 59° Fahrenheit, barometer 29*45. ExD o n

Some of the animal charcoal of the last experiment was animal char-
heated to redness under sand for one hour, four grains °°a
were placed in the platina tray ; and as we were so much
embarrassed in the last experiment with the saline matter
w|vich adhered to the tray, we exactly balanced it with its
contents. Our oxigen, made as usual, left a residuum of 2
parts in 100, and we began with 49*34 cubic inches. When Flashn>oi'
every thing was adjusted, and the platina tube red hot, on nSlu«
parsing the oxigen, flashes resembling lightning ran along
the glass tube ; and this was repeated 5 or 6 times. The Gas tulfc-I(j#
whole of the gus became very cloudy, exhibiting a turbid

*iilkj

IPI ON THE QUANTITY Otf CARBON IN CARBONIC ACID.

milky appearance. The tube was rendered white hot by the
combustion of the carbonaceous matter in oxigen. The fire
was kept up about S minutes, and the gas passed several
times. When all was cool, we could observe no alteration
in the volume of gas by the register. The tray contained a
mixture of salts; and being weighed, was lighter by 3*2
Residuum 8 grains. This loss was not wholly carbon, for it is well known
if18' that animal substance contains a variety of salts, as phos-

phates, muriates, &c. some of which, though not volatile in
a low red heat, might be decomposed and dissipated in the
intense white heat produced by the combustion of the car-

Siight efflores- kQnaceoug matter in oxigen ; and we accordingly found the
cence on the . n .

interior of the internal parts of the gasometers and tubes very slightly co-
apparatus, vered with a soFt of efflorescence. On examining the gas
after the experiment,

Lime water absorbed 41 parts from 100
The tests for oxigen 55
Residual <*as Residuum .• • 4 or an increase of 2.

increased '02.

100

Correction for temperature.
6d° 49*84

59 -10 add for temp.

1 diff, or 0*103 49*94

Correction for pressure;
30 : 29*45 : : 49D4 : 49*02.

The quantity of oxigen at the mean would therefore b«
49*02 cubic inches.

100 : 41 : : 49*02 : 20*09

Carbonic acid The carbonic acid gas produced was therefore 20*09 cubic

^produced mches>
20 G9£ub in.

100 :47*2G:: 20-09: 9-49

and this carbonic acid weighed 9*49 grains.

Now the coal in the tray had lost 3*2 grains; but as the
whole of this was not carbon, but part of it volatile saline

matter,

ON THE QUANTITY OF CARBON TN CARBONIC ACID* £35

matter, &c. we shall endeavour to estimate the carbon by
the experiment on plumbago. When 13*35 grains of car-
bonic acid contained 3*80 grains of carbon,

13-35:3-80 :: 9*49: 270.
The quantity of carbonic acid produced in this experiment, Containing 2*7
therefore, contained 2*70 grains of carbon. fir3 of carbon*

Loss 3*20

Carbon 270

Leaves *50 for volatile saline matter, &c.

So that, this being granted, the present experiment agrees Matter volati-
with the foregoing. lizeel/*5 Srs'

In two of our first experiments with box-wood charcoal, jn some eXpe.
the calculations gave us in one case 2975 parts of carbon in fiments quan-
100 of carbonic acid, and the other 30*68; but we were apparently ^
not then fully aware of the absorption of water by charcoal, greater.
which rendered the quantity of real carbon employed less
than indicated by the weight. Also in another experiment,
in which 4 grains of diamond were consumed, the calcula-
tion gave us 29*06 per cent of diamond in carbonic acid ;
but apprehending, that a slight degree of inaccuracy had
crept into this experiment, we have not detailed it with the
rest ; but we have thought it right to give a simple statement
of matters of fact; in no one instance have we endeavoured
to strain or accommodate these to suit any particular theory,
being fully aware, that every experiment, carefully made and
faithfully recorded, will remain an immutable truth to the
end of time, while hypotheses are constantly varying, and
even the most beautiful theories are liable to change.

The experiments above related give us the following results.

. By carbonic acid. By oxigen.

Box-wood charcoal • • 23 92
lstexpt. diamond ■ . . . 28*95
'id expt. diamond • • . • 28*82

Stone dotal 28*20

Plumbago ,. . 28*46

2877

Table of re-

28-81

suits.

28*72

28*27

28*46

>) 143*35 * 5)143*03

mean 2S*67 28*60

Hence,

£36 0\ THE QUANTITY Ot? CARfeOtt IN CARBONIC ACID.

100 grs. carbo- Hence we conclude, that 100 grains of carbonic acid con*
fainTs^of" tam 28'GO °f carbon, which docs not greatly differ from the
carbon. results of the experiments of SmithsOn Tennant, Esq. oa

the nature of diamond. See Phil. Trans. 1797.
Mr. Tennant's This gentleman made his experiment in the following
experiment! nianuer. A quarter of an ounce of nitrate of potash was
rendered somewhat alkaline by exposure to heat, in order
that it might more readily absorb carbonic acid ; it was then
put into a gold tube with 2§- grains of diamond, and being
subjected to heat, the diamond was converted iuto carbonic
acid, by uniting with the oxigen contained in the nitric acid.
The carbonic acid thus produced combined with the potash,
and on pouring a solution of muriate of lime into a solution
of this salt, he obtained a precipitate of carbonate of lime,
this, being decomposed by muriatic acid, gave as much car-
bonic acid gas as occupied the space of 10*1 ounces of wa-
ter. The thermometer was at 55° Fahrenheit, the barome-
ter 2j)'80. In a second experiment he procured a larger
quantity, or equal to 10*3 ounces of water.
ga?e27or27-8. If we therefore consider an ounce of water as consisting
of 480 grains, and a cubic inch of water equal to 2o3 grains,
and then make the proper corrections for temperature and
pressure, one of his experiments will give about 27 per cent,
the other about 27*80 for the carbon in carbonic acid, which
is somewhat less than our estimate; but the difference may
easily be accounted for, from the different methods employed.
Guytoirsex- The experiments of Guyton, as detailed in the Annates de

fo iiTe"ennd0ed Chimie> vol« X*XI, P*ge 7&, are liable to very strong objec-
ou. tions ; but at the same time the candid manner, in which he

has related every circumstance, merits considerable praise.
ft is impossible, however, not to observe, that the quantity of
gas before and after the experiment could not, from the
construction of his apparatus, be very rigorously ascertained.
We object also to nitrous gas as a test for oxigen ; and as it
is acknowledged, that the wooden support included in the
oxigen gas took fire, the product of carbonic acid must have
been influenced by it ; so that, if no chance of errour had
existed in estimating the carbonic acid gas from the residuum
after barytic water had absorbed a part, still the result would
Lot have been satisfactory.

The

EXTINCT VOLCANO IN BRITAIN. 237

The experiments which we have had the honour of laying General con-
« „ , - r, l • • 4. elusions.

before this Society prove several important points:

]st. That the estimate given by Lavoisier, of 23 parts of Lavoisier's es*
carbon in every 1 00 parts of carbonic acid, is very nearly £0^**.°*^
Correct; the mean of our experiments makes it 28*60.

2dly. That the diamond is pure carbon; for had it con- Diamond pure
tained any notable proportion of hidrogen, it must have carbon.
been discovered, either by detonating with the oxigen, as in
the case of animal charcoal, or by diminishing the quantity
of oxigen gas.

3clly. That well burnt charcoal contains no sensible quan- Fresh charcoal
tity of hidrogen ; but if exposed to the air for a few hours it contains no hi-
absorbs moisture, which venders the results uncertain. a

4thly. That charcoal can no longer be considered as an Charcoal not
oxide of carbon, because, when properly prepared, it requires oxl'le-
quite as much oxigen for its combustion as the diamond.
This is also the case with stone coal and plumbago.

5thly. It appears that diamond and all carbonaceous sub- Carbonaceous
stances (as far as our present methods of analysis are capable f"r oSHntheir
of demonstrating their nature) differ principally from each aggregation.
other in the state of aggregation of their particles. Berthol-
let has well remarked, that in proportion as this is stronger,
decomposition is more difficult : and hence the variety of
temperatures required for the combustion of different inflam-
mable substances.

IX.

Account of an extinct Volcano in Britain. Communicated by
Mr. Donovan.

_R. Donovan announces some particulars of an extraor- Cader Idris for^
dinary nature to the scientific world respecting one of the |^er y
Cambrian mountains; which, from the result of attentive
observation, and indubitable evidence, he endeavours to de-
monstrate must have been at some remote period a volcano

of

33S EXTINCT VOLCANO IN ElllTAlN.

of immense magnitude. The mountain alluded to is Cader

Idris, situate in* the. county of Merioneth, which in point of

size is esteemed the most considerable in the principality of

Wales, Snowdon alone excepted*

First noticed The remarkable appearance of this, stupendous mountain

J^r' no* attracted the attention of Mr. Donovan about seven years
vuii seven y eurs

a«°- ago. He was then led to consider from a variety of circum-

stances, that iLe original form of the mountain must have
undergone very material alteration,, occasioned as he con-
ceived by the powerful effects of the volcanic explosion ; but
his remarks were not .sufficiently precise to authorise the as-
sertion. Since that period he has examined the mountain
in a less cursory manner, more especially in the summer of
1307, when he was at .full leisure to devote some time to this
interesting subject of inquiry, and his observations in the
latter instance tend entirely to confirm the idea iir&t sug-

Proofsinvol- gested. In support of tiiis opinion Mr. Donovan has now

came produc- a(Jded to h\s mUseum abundant examples of different kind*
twrib collected r

there m ISO 7. °f lava, pumice, and other volcanic matters of the most une-
quivocal character, collected by himself from the sides and
base of the mountain ; and also a suite of the remarkable and
singularly formed columnar crystals of basalt, that are scat-
tered in profusion about the loftiest summit, and cliffs sur-
rounding the crater.
Appearance of The general aspect of this crater is exactly that of mount
the crater. Vesuvius, except that one of its sides is broken down, by
which means the abyss of this funnel-shaped excavation is
Wiore completely dis^lo;-**! than in the Vesuvian mountain ;
and it this side of Cader ldris which affords the most illus-
trative examples of porous stones, these forming immense
beds on the declivities a few inches only in many instances
below the surface of the, eaith. A number of these porous
. stones lately found in this spot by Mr. Donovan exhibit evi-
dent marks of strong ignition and' vitrification, some are re-
duced to the state of slags, while others have all the cel£ular
1 lightness of pumice.

appearance and

V» 'jthout entering upon any discussion as to the relative

formed by an merits of the neptunian and vulcanian theories, it must be

2 er1™ admitted, that the agency of water might have contributed

materially to affect those changes in the primitive form of tfie

Cader

EXTINCT VOLCANO IN. EKITAIN.1 &KL

Cader Idrie mountain, which have evidently taken place.
But with respect to the crater itself, this appears very clearly
to have derived its origin from the violence of an explosion
upwards, in which a very considerable portion of the highest
eminence was torn from its native bed of rocks, and thrown
to a considerable height over the other parts of the moun-
tain. In confirmation of this suggestion it should be men- Proof* of this,
tioned, that the summit of the mountain is covered with an
immense wreck of the stones, ejected as it is presumed from
the crater at the time of this explosion ; it would be difficult
otherwise to account for the vast profusion of tljose stones
scattered in all- directions about the loftiest elevations, and
which, from the confused manner 'in which they are dis-
persed, must have been thrown into iheir present situation by
no small violence. Myriads of these stones have borne a
regular crystallized form, though from their great bulk and
weight they have for the most part suffered material injury
in the general convulsion. The usual length of these crys- Columnar
tals is from three to six or ten feet in length : some itte'&tire^^ feet long,
even fifteen or twenty, and one in: particular, which Mr.
Donovan has seen, was twenty-two feet three inches long*
They are however slender in proportion to the length.

^The substance of these crystals is of the basalt kind, aud Basil tes.
corresponds very nearly with some varieties of the «' lave
porphyrc" of Etna described by Dolomieu, and Faujas de
St. Fond ; and in the form of its crystals agrees with others
of the basaltes prismatlque of the last author.. In the nep-
t urn ran theory it is not indeed admitted ,as a basalt, but as a
porphyry argil. It is the porphir-schtefcr of Werner, "ana
porphyry slate, or clinkstone porphyry of Jamieson.

The suite of these stupendous crystals, which Mr. Dono- Specimens of
van collected from tb6 summit of Cader Idris last summer, 1*™J^J ]?*
and has lately added to his museum, consists of a small tri-
hedral column about eighteen inches in length ;.a tetrahedral
column of much superior size ; an interesting portion of a
pentagonal column', and another of the san\e figure about
fwur feet in length, and having the termination of the crys-
tal complete. The latter is estimated at about five hundred
weight, but this is still exceeded by another of a somewhat
compressed hexagonal figure with an oblique termination.

novatrs r
»eum.

<240 SCIENTIFIC MEWS.

The whole of these are verv 'perfect, and extremely well de-
fined.

Lambeth, Feb. 22</. 1808*

■■**? * «• r

SCIENTIFIC NEWS.
New mode of preparing Calomel,

[E object of this process, invented by Mr. Joseph
Jewel, is to produce a cak.r.el, that shall always be in the
state of an impalpable powder. In the common mode this is
effected by grinding, or trituration, which is liable to
"be negligently performed 1 and Mr. Jewel, to prevent all.
danger of this, endeavours to obtain it in a powder uniformly
fine, by a particular manipulation in the last sublimation of
the calomel, which he describes as follows.

I take calomel or mercurius dulcis, broken into small
pieces, and put it into an earthen crucible of the form of a
long bowl, so as to fill about one half thereof. I place the
crucible on its side in a furnace provided with an opening,
through which the mouth of the crucible projects about an
inch. I then join to the mouth of the crucible an earthen
ware receiver, having an opening at its side, to receive the
open end of the crucible. This receiver is about half filled
with water. I lute the joint with a mixture of sand and pipe
clay. The receiver has a cover, which cover has a side con-
tinued upwards for containing water, with a chimney or tube
in it, to allow the escape of steam from the water below. I
then apply a fire around the crucible, sufficient to raise the
calomel in vapours, and forced it through the mouth of the
crucible into the receiver ; where, by the water while cold, or
assisted by the steam when it becomes hot, it is instantly
condensed into an impalpable powder, possessing all the
qualities of calomel in its most perfect state. The calomel,
when thus prepared, is purer, whiter, and more attenuated,
than that obtained by grinding. It is proper to wash the
product over with water, before it is dried, to rid it of any
courser particles, which may form about the mouth of the
crucible.

A

JOURNAL . .

OP

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

APRIL, 1808.

ARTICLE I.

On (he formation of the Bark of Trees. In a Letter from T. A,
Knight, Esq. F. R. S. to the Right Honourable Sir Joseph
Banks, K. B. P. R. S. #c*.

My Dear Sir,

.A.N extraordinary diversity of opinion appears to have Vaiious
prevailed among naturalists, respecting the production and opinions re-
subsequent state of the bark of trees. production ©f

According to the theory of Malpighi, the cortical sub- bark,
stance, which is annually generated, derives its origin from
the older bark ; and the interior part of this new substance is
annually transmuted into alburnum or sap wood; whilst the
exterior part, becoming dry and lifeless, forms the exterior
covering or cortex.

The opinions of Grew do not appear to differ much from
those of Malpighi ; but he conceives the interior bark to con-
sist of two distinct substances, one of which becomes albur-

* Philos. Tras. for 1806, Part I, p. 103. Sir Godfrey Copley's gold
medal for 1806 was adjudged to Mr. Knight for his various papers on
vegetation printed »n the Phil. Trans.

Vol. XIX. No. 84.— April, 1808. R num.

5J42 FORMATION OF THE BARK OF TREES.

num, whilst the other remains in the state of bark: he, how-
ever, supposes the insertments in the wood, the " utriculi" of
Malpighi, and the " tissu cellulaire" of du Hamel, to have
originally existed in the bark.

Hales on the contrary contends, that the bark derives its
1 existence from the alburnum, and that it does not undergo
any subsequent transformation.

The discoveries of du Hamel have thrown much light on
the subject; but his experiments do not afford any conclu»
sive result, and some of them may be adduced in support of
either of the preceding hypotheses : and a modern writer
(Mirbel*) has endeavoured to combine and reconcile, in
some degree, the apparently discordant theories of Malpighi
and Hales. He contends with Hales, that the alburnum
gives existence to the new layer of bark ; but that this bark
subsequently changes into alburnum, though not precisely
in the manner described by Malpighi.

So much difference of opinion, amongst men so capable of
observing, sufficiently evinces the difficulty of the subject they
endeavoured to investigate: and in a course of experiments,
which has occupied more than twenty years, I have scarcely
felt myself prepared, till the present time, even to give an
opinion respecting the manner in which the cortical substance
is geuerated in the ordinary course of its growth; or repro^
duced, when that, which previously existed, has been taken
off.
Bark of some Du Hamel has shown, that the bark of some species of
treesrepro- trees is readily reproduced, when the decorticated surface of
the alburnum is secluded from the air; and 1 have repeated
similar experiments on the apple, the sycamore, and other
trees, with the same result; I have also often observed a si-
milar reproduction of bark on the surface of the alburnum
of the wj/ch elm (ulmus montana) in shady situations, when
apparently no covering whatever was applied. A glareous fluid, as du

from the al- Hamel has stated, exudes from the surface of the alburnum :
burnura. , . _ . , , , ,

this fluid appears to change into a pulpous unorganized mass,

which subsequently becomes organized and cellular; and the

* Traite d'Anatonrie et de Physiologic vegetale.

matter,

FORMATION OF THE BARK OF TREES. $&3

matter, which entere into the composition of this cellular

substance, is evidently derived from the alburnum.

These facts are therefore extremely favourable to the

theory of Hales ; but other facts may be adduced, which are

scarcely consistent with that theory.

The internal surface of pieces of bark, when detached Internal sar-
• , , i. • i i l l i face of the bark

from contact with the alburnum, provided they remain united itSelf generates

to the tree at their upper ends, much more readily generate it more readily,
a new bark, than the alburnum does under similar circum-
stances: a similar fluid exudes from the surfaces of both,
and the same phenomena are observable in both cases. The
Cellular substance, however, which is thus generated, though
it presents every external appearance of a perfect bark, is
internally very imperfectly organized; and the vessels which
contain the true sap in the bark are still wanting; md I Course of the
have found, that these may be made, by appropriate manage- "arTabhT* *
ment, to traverse the new cellular substance in almost any
direction. When I cut off all communication above, and
on one side, between the old bark and that substance, I ob-
served, that the vessels proceeded across it, from the old bark
on the other side, taking always in a greater or less degree an
inclination downwards; and when the cellular substance re-
mained united to the bark at its upper end only, the vessels
descended nearly perpendicularly down it; but they did not
readily ascend into it, wtten k was connected with the bark at its
lower extremity only; the result of similar experiments, when
made on different species of trees, was, however, subject to
some variations.

Pieces of bark of the walnut-tree, which were two inches Experimentoti
broad, and four long, having been detached from contact the walnut*
with the alburnum, except at their upper ends, and covered
with a plaster composed of bees-wax and turpentine, in
some instances, and with clay only in others, readily gene-
rated the cellular substance of a new bark; and between that
and the old detached bark, very nearly as much alburnum
was deposited as in other parts of the tree, where the bark re-
tained its natural position; which. I think, affords very deci-
sive evidence of the descent of the sap through the bark. The ?ap de.

Similar pieces of bark, under the same mode of treatment, scendsthrough

r» r* t. ^ the bark.

R2 but

£44< FORMATION' OF THE BARK OF TREKS.

but united to the tree at their lower ends only, did not long
remain alive, except at their lower extremities; and there a
very little alburnum only was generated. Other pieces of
bark of the same dimensions, which were laterally united to
the tree, continued alive almost to their extremities : and a
considerable portion of alburnum was generated, particularly
near their lower edges; the st p appearing in its passage
across the bark to have been given a considerable inclination
downwards: probably owing to an arrangement in the or-
ganization of the bark, that I have noticed in a former me-
moir*, which renders it better calculated to transmit the sap
towards the roots than in any other direction.
Bark repro- I have in very few instances been able to make the walnut-

alburaunTof16 trce rePro^uce its bark from the alburnum, though under the
the sycamore same management I rarely failed to succeed with the syca-
app e. more and apple tree. Pieces of the bark of the apple-tree
will also live, and generate a small portion of alburnum,
though only attached to the tree at their lower extremities;
probably owing to a small part of the true sap being carried
upwards by capillary attraction, when the proper action of
the cortical vessels is necessarily suspended.

The preceding experiments, and the authority of du Ha-
mel, having perfectly satisfied me, that both the alburnum
and the bark of trees are capable of generating a new bark,
or at least of transmitting a fluid capable of generating a
cellular substance, to which the bark in its more perfectly
organized state owes its existence, my attention was directed
to discover the sources from which this fluid is derived.

Both bark and Both the bark and the alburnum of trees are composed
alburnum con- . . .. - -:. , c , j , . ■ c ,

sist of tubes and principally of two substances; one ol which consists of long

celluiarsub* tubes, and the other is cellular; and the cellular substance

of the bark is in contact with the similar substance in the

alburnum, and through these I have long suspected the true

sap to pass Irom the vessels of the bark to those of the albur-

numf. The intricate mixture of the cellular and vascular

substances long baffled my endeavours to discover from which

* Philosophical Transactions of 1804, or Philosophical Journal, vol.
X, p. 289.

f Phil. Trans. 1805, p. 14, or Philos. Journal, vol. XIII, p. Cb2.

of

FORMATION OF THE BAUK OF TREES. 24J

of.tlicm, in the preceding cases, the sup, and consequently
the new bark, proceeded; but I was ultimately successful.

The cellular substance, both in the alburnum and bark of Experiments
,, , . <■ • , • c ,. . on pollard

old pollard oaks, often exists in masses ot near a Jine in 03^s%

width, and this organization was peculiarly favourable to my
purpose. I therefore repeated on the trunks of trees of
this kind experiments similar to those above mentioned,
which were made on the walnut-tree.

Apparently owing to the small quantity of sap, which the
old pollard trees contained, their bark way very imperfectly
reproduced j but I observed a fluid 10 ouze from the cellular
substance, both of the bark and alburnum ; and on the sur-
face of these substances alone, in many instances, the new
bark was reproduced in small detached pieces.

I have endeavoured to prove in former communications*, Absorbed fluid

. . - ^ .' ' , ill- converted into

that the true sap ot trees acquires those properties which dis- sap by circu]a.

tinguish it from the fluid recently absorbed, by circulating tion in the leaf,
through the leaf; and that it descends down the bark, where SCe1M]s down
part of it is employed iri generating the new substances an- the bark, to
jmally added to the tree; and that the remainder, not thus ^^Cq^W SU
expended, passes into the alburnum, and there joins the as-
cending current of sap. The cellular substance, both of
the bark and alburnum, has been proved, in the preceding
experiments, to be capable of affording the sap a passage
through it; and therefore it appears not very improbable,
that it executes an office similar to that of the anastomosing
vessels of the animal economy, when the cellular surfaces of
the bark and alburnum are in contact with each other; and,
when detached, it may be inferred, that the passing fluid
will exude from both surfaces: because almost all the vessels
of trees appear to be capable of an inverted action in giving
motion to the fluids which they carry.

As the power of generating a new bark appeared in the Sap ascending
preceding cases to exist alike in the sap of the bark and of shoots can _e.
the alburnum, I was anxious to discover how far the fluid, "erate new
which ascends through the central vessels of the succulent
annual shoot, is endued with similar powers. Having tliero-

* Phil. Trans 1801, 1805, and 1806.

fore

24:6 FORMATION OF THE BARK OF TREES.

fore made two circular incisions through the bark, rount£
the stems of several annual shoots of the vine, as early in tho
summer as the alburnum within them had acquired sufficient
maturity to perform its office of carrying up the sap, I toofo
off the bark between these incisions; and I abraded the sur-
face of the alburnum to prevent a reproduction of it. The
alburnum in the decorticated spaces soon became externally
dry and lifeless ; and several incisions were then made lon-
gitudinally through it. The incisions commenced a little
above, and extended below the decorticated spaces, so that,
if the sap of the central vessels generated a cellular sub-
stance (as I concluded it would), that substance might come
into contact and form a union with the substance of the
same kind emitted by the bark above and below.

The experiment succeeded perfectly, and the cellular sub-
stances generated by the central vessels, and the bark, soon
united, and a perfect vascular bark was subsequently formed
beneath the alburnum, and appeared perfectly to execute the
office of that which had been taken off; the medulla ap-
peared to be wholly inactive.
Cortical vessels I nave already observed, that the vessels, which were
from regenera- generated in the cellular substance on the surface of the al-
ia various di- hurnum of the sycamore and the apple-tree, traversed that
sections. substance in almost every direction; and the same thing ap-

pears to occur beneath the old bark, when united to the al-
burnum. For having attentively examined, through every
part of the spring and summer, the formation of the interna}
bark, and al burnous layer beneath it, round the bases of re-
generated buds, which I had made to spring from smooth
spaces on the roots and stems of trees, I found every appear-
ance perfectly consistent with the preceding observations.
A single shoot only was suffered to spring from each root and
stem, and from the base of this, in every instance, the cortical
vessels dispersed themselves in different directions. Some de-
scended perpendicularly downwards, whilst others diverged
on each side, round the alburnum,' with more or less inclina-
tion downwards, and met on the opposite side of it. The
same, pulpous and cellular substance appeared to cover the
surfaces of the bark and alburnum, when in contact with

cacb

FORMATION OF THE BARK OF TREES. 247

each other, as when detached ; and through this substance

the ramifications of the vessels of the new bark extended

themselves, appearing to receive their direction from the fluid

sap, which descended from the bark of the young shoots, and

not to be, in any degree, influenced in their course by the

direction taken by the cortical and alburnous vessels of the

preceding year.

Whenever the vessels of the bark, which proceeded from Cortical vessels
, . ' . , , . A meeting form,

different points, met each other, an interwoven texture was an interwoven

produced, and the alburnum beneath acquired a similar or- texture,
ganization; and the same thing occurs, and is productive of
very important effects, in the ordinary course of the growth
of trees. The bark of the principal stem, and of every la- Junction of la-
teral branch, contains very numerous vessels, which are tera ranc es*
charged with the descending true sap; and at the juncture
of the lateral branch with the stem, these vessels meet each
other. A kind of pedestal of alburnum, the texture of
which is much interwoven, is in consequence formed round
the base of the lateral branch ; which thus becomes firmly
united to the tree. This pedestal, though apparently a part
of the branch, derives a large portion of the matter, annually
added to it, from the cortical vessels of the principal stem ;
and thence, in the event of the death of the lateral branch,
it always continues to live. But it not unfrequently happens, Weak when

that a lateral branch forms a very acute angle with the fornun£ a very

acute angle,
principal stem, and, in this case, the bark between them be-
comes compressed and inactive; no pedestal is in conse-
quence formed, and the attachment of such a branch to the
stem becomes extremely feeble and insecure*. Instead of

* The advantages, which may be obtained by pruning timber trees ju- Advantages of
diciously, appear to be very little known. I have endeavoured to as- Pr0Perly prun-
certain the practicability of giving to trees such forms as will render their in* timber
timber more advantageously convertible to naval or other purposes, trees.
The success of the experiments, on small trees, has been complete, and
the results perfectly consistent, in every case, with the theory I have
endeavoured to support in former memoirs ; and I am confident, that by
appropriate management, the trunks and branches of growing trees may
be moulded into the various forms best adapted to the use of the ship-
builder •, and that the growth of the trees may at the same time be ren-
dered considerably more rapid, without any expense or temporary loss to
the proprietor.

248 FORMATION OF THE BARK OF TREES.

the reproduced buds of the preceding experiment, buds were
inserted in the foregoing summer, or attached by grafting in
the spring ; and, when these succeeded, though they were in
many instances taken from trees of different species, and
even of different genera, no sensible difference existed in th$
vessels, which appeared to diverge into the bark of the
stock, from these buds and from those reproduced in the
preceding experiments.
Theory. It appears, therefore, probable, that a pulpous organizable

mass first derives its matter either from the bark, or the al-
burnum ; and that this matter subsequently forms the new
layer of bark ; for, if the vessels had proceeded, as radicles*,
from the inserted buds or grafts, such vessels would have
been in some degree different from the natural vessels of the
bark of the stocks ; and it does not appear probable, even
without referring to the preceding facts, that vessels should
be extended, in a few days, by parts successively added to
their extremities, from the leaves to the extremities of the
roots ; which are, in many instances, more than two hundred
feet distant from each other. I am, therefore, incline^ to
believe, that, as the preceding facts seem to indicate, the
matter, which composes the new bark, acquires an organiza-
tion calculated to transmit the true sap towards the roots, as
that fluid progressively descends from the leaves in the
spring; but whether the matter, which enters into the compo-
sition of the new bark, be derived from the bark or the albur-
num, in the ordinary course of the growth of the tree, it will
be extremely difficult to ascertain.
Bark some- It is, however, no difficult task to prove, that the bark does

times exists nof jn a|j cas€S spring from the alburnum ; for many cases
previous to the ' ,, ,..",.., ' . ,

alburnum. may be adduced, in which it is always generated previously to

the existence of the alburnum beneath it; but none, I be-
lieve in which the external surface of the alburnum exists
previously to the bark in contact with it. except when the
cortical substance has been taken off, as in the preceding
experiments. In the radicle of germinating seeds, the cor-
tical vessels elongate, and new portions of bark are succes-

• Darwin's Phytologia.

sive)y

FORMATION OF THE BARK OF TREES.

249

sively added to their points, many days before any albiirnous
substance is generated in them ; and in the succulent an-
nual shoot the formation of the bark long precedes that of
ttie alburnum. In the radicle the sap appears also evidently
to descend* through the cortical vesselsf, and in the succu-
lent annual shoot it as evidently passes up through the cen->
tral vessels}, which surround the medulla. In both cases a
cellular substance, similar to that which was generated in
the preceding experiments, is first formed, and this cellular
substance in the same manner subsequently becomes vascu-
lar; whence it appears, that the true sap, or blood of the
plant, produces similar effects, and passes through similar
stages of organization, when it flows from different sources,
and that the power of generating a new bark, properly speak-
ing, belongs neither to the bark nor alburnum, but to a fluid,
which pervades alike the vessels of both,

I shall, therefore, not attempt to decide on the merits of Bark not tran*
the theory of Malpighi, or of Hales, respecting the reproduc- mutpd intoaj-
tion of the interior bark ; but I cannot by any means admit
the hypothesis at Malpighi and other naturalists, relative to
the trasmutation of bark into alburnum; and I propose to
state my reasons for rejecting that hypothesis, in the ne$t
communication I have the honour to address to you.

I am, my dear Sir,

Your most obliged obedient Servant,

FMon, Dec. 18, 18 Off. T. A. KNIGHT.

* Phil. Trans, 1805 and 1806, or Philos. Journal, vol. XIII and XVL

+ I wish it to be understood, that I exclude in fhese remarks, and in
those contained in my former Memoirs, all trees of the palm kiad, with
the organization of which I am almost wholly unaccquainted.

% Phil. Trans. 1805. Mirbel has called the tubes, which I call the
central vessels, the " tissu tubuiaire" of the medulla. •

If.

$50 °* TnE ECONOMY OF BEES.

II.

On the Economy of fyes. In a Letter from Thomas An-
drew Knioht, Esq. F.R.S. to the Right Honourable
Sir Joseph Banks, Bart. KB. P.R.S.*

My dear Sir,

I

N the prosecution of those experiments on trees, accounts
of which you have so often done me the honour to present
to the Royal Society, my residence has necessarily been al-
most wholly confined to the same spot ; and I have thence
been induced to pay considerable attention to the economy
of bees, amongst other objects ; and as some interesting
circumstances in the habit of these singular insects appear
to have come under my observation, and to have escaped the
notice of former writers, I take the liberty to communicate
my observations to you.
Friendly inter- It is, I believe, generally supposed, that each hive, or swarm,

course takes Qf these insects remains at all times wholly unconnected with
place bet.veen ....... . . / . ...

bees of differ- other colonies in the vicinity; and that the bee never distin-

«it swarms. guishes a stranger from an enemy. The circumstances which

I shall proceed to state will, however, tend to prove, that these

opinions are not well founded, and that a friendly intercourse

not unfrequently takes place between different colonies, and

is productive of very important consequences in their political

economy.

Evening visits Passing through one of my orchards rather late in the

between two ^venmg m the month of August, in the year 1801, I ob-

served, that several bees passed me in a direct line from the

hives in my own garden to those in the garden of a cottager,

which was about a hundred yards distant from it. As it was

considerably later in the evening than the time when bees

usually cease to labour, I concluded, that something more

than ordinary was going forward. Going first to my own

garden, and then to that of the cottager, I found a very

considerable degree of bustle and agitation to prevail in one

hive in each : every bee, as it arrived, seemed to be stopped

* PhUos. Trans, for 1807, Part II, p. 234.

and

ON THE ECONOMY OF BEES. 251

»nd questioned, at the mouth of each hive ; but I could not
discover any thing like actual resistance, or hostility, to take
place; though I was much inclined to believe the intercourse
between the hives to be hostile and predatory. The same
kind of intercourse continued, iu a greater or less degree;
during eight succeeding days, and though I watched them
very closely, nothing occurred to induce me to suppose,
that their intercourse was not of an amicable kind. On the Ended in a
tenth morning, however, their friendship ended, as sudden Huarre»*
•and violent friendships often do, in a quarrel ; and they ,

fought most furiously ; and after this there was no more vi»
siting.

Two jears subsequent to this period I observed the same Similar inter-
kind of intercourse to take place between two hives of my course between
own bees, which were situate about two hundred yards dis- hives,
tant from each other ; they passed from each hive to the
other just as they did in the preceding instance, and a simi-
lar degree of agitation was observable. In this instance,
however, their friendlhip appeared to be of much shorter Quarrelled oi»
duration, for they fought most desperately on the fifth day; tne fi*lh 4ar,
and then, as in the last mentioned case, all further visiting
ceased.

I have some reason to believe, that the kind of intercourse Sometimes

I have described, which I have often seen, and which is by two swarm*

r. .i j • • form a June*

no means uncommon, not untrequently ends in a junction t\oaf

of the two swarms ; for one instance came under my obser-
vation, many years ago, in which the labouring bees, under
•circumstances perfectly similar to those I have described,
wholly disappeared, leaving the drones in peaceable posses-
sion of the hive, but without any thing to live upon. I have
also reasons for believing, that whenever a junction of two
swarms, with their property, is agreed upon, that which pro-
poses to remove, immediately, or soon afterward, unites
with the other swarm, and returns to the deserted hive during
the day only to carry off the honey : for having examined at
night a hive from which I suspected the bees to be migrat-
ing, I found it without a single inhabitant. I was led to
make the examination by information I had received from a
very accurate observer, that all the bees would then be ab-
sent. A very considerable quantity of honey was in this in-
stance

£5£ 99 THE ECONOMY OF BEES.

stance kft in the hive without any guards to defend it; but
I conclude, that the bees would have returned for it, had it
remained till the next day. Whenever the bees quit their
habitation in this way, I have always observed some fighting
to take place ; but I conceived it to be between the bees of
the adjoining hives, and those which were removing; the for-
mer being attracted by the scent of the honey, which the lat-
ter were carrying off.
feessefflihgm On the farm which I occupy, there were formerly many
appear totend °^ decayed trees, the cavities of which were frequently oc-
out scouts to cupied by swarms of bees ; and when these were destroyed,
afteranYndl/i- a board was generally fitted to the aperture, which had been
dual has in- made to extract the honey; and the cavity was thus prepared

formed them for tj,e reception of another swarm, in the succeeding season.

of a proper r °

place. Whenever a swarm came, I constantly observed, that about

fourteen days previous to their arrival, a small number of
bees, varying from twenty to fifty, were every day employed
in examining, and apparently in keeping possession of the
cavity ; for if molested, they showed evident signs of dis-
pleasure, though they never employed their stings in defend-
ing their proposed habitation. Their examination was not
confined to the cavity, but extended to the external parts of
the tree above; and every dead knot particularly arrested
their attention, as if they had been apprehensive of being
injured by moisture, which this might admit into the cavity
below ; and they apparently did not leave any part of the
bark near the cavity unexamined. A part of the colony,
which purposed to emigrate, appeared in this case to have
been delegated to search for a proper habitation ; and the
individual who succeeded must have apparently had some
means of conveying information of his success to others; for
it cannot be supposed, that fifty bees should each acciden-
tally meet at, and fix upon, the same cavity, at a mile dis-
tant from their hive, which I have frequently observed them
to do, in a wood where several trees were adapted for their
reception ; and indeed I observed, that they almost uni-
formly selected that cavity, which I thought best adapted to
their use.

It not unfrequently happened, that swarms of my own
bees took possession of these cavities, and such swarms were

ON THE ECONOMY OF BEES. 253

\

ia several instances followed from my garden to the trees :
and they were observed to deviate very little from the direct
line between the one point and the other; which seems to in-
dicate, that those bees, which had formerly acted as purveyors,
now became guides.

Two instances came under my own observation, in which a Swarms admit?
swarm was received into a cavity, of which another swarm in^hoUows
had previous possession. In the tirst instance I arrived with already occu-
the swarm, and I could not discover, that the least oppoai- pi *
tion was made to their entrance: in the second instance, ob-
serving the direction that the swarm took, I used all the ex-
pedition 1 could to arrive tirst at the tree, to which I supposed
they were going, whilst a servant followed them ; and a de-
scent of ground being in my favour, and the wind against
them, I succeeded in arriving at the tree some seconds be-
fore them ; and 1 am perfectly confident, that not the least
resistance was opposed to their entrance. to.ij

Now it does not appear probable, that animals so much A previous

attached to their property as bees are, so jealous of all ap- communit'attoit
i j-i i n i • »• i between them

proach towards it, and so ready to sacrifice their lives in de- must have

fence of it, should suffer a colony of strangers, with whose taken place,
intentions they were unacquainted, to take possession, with-
out making some effort to defend it: nor does it seem much
more probable, that the same animals, which spent so much
time in examining their future habitation, in the cases I have
mentioned, should have attempted in this case to enter
without knowing whether there was space sufficient to con-
tain them, and without any examination at all. I must
therefore infer, that some previous intercourse had taken
place between the two swarms, and that those in the posses-
sion of the cavities were not unacquainted with the inten-
tions of their guests; though the formation of any thing
like an agreement between the different parties be scarcely
consistent with the limitations generally supposed to be
fixed by nature to the instinctive powers of the brute crea-
tion.

Brutes have evidently language; but it is a language of Brutes have
passion only, and not of ideas. They express to each other lan§uage to
sentiments of love, of fear, and of anger; but they appear sions only :
to be wholly incapable of transmitting to each other any

ideas

£54 on tub ecoxomt or bees.

ideas they have received from the impression of external
objects* They convey to other animals of their species, on
the approach of an enemy, a sentiment of danger; but
they appear wholly incapable of communicating what the
but bees must enemy is, or the kind of danger apprehended. A language
communicate Qf more extensive use seems, from the preceding circum-
stances, to have been given to bees; and if it be not, in some
degree, a language of ideas, it appears to be something very
similar.
A colony of "When a swarm of bees issues from the parent hive, they

bees settles generally soon settle on some neighbouring bush or tree ;
soon after quit- & . . . . . . . rt. B _ ' , ,

ting the hive. and as in this situation they are generally not at all defended

from rain or cold, it is often inferred, that they are less am-
ply gifted with those instinctive powers, that direct to self-

This merely to preservation, than many other animals. JBut their object in

tr together^" settling soon after they leave the hive is apparently nothing
more than to collect their numbers ; and they have gene-
rally, I believe always, another place to which they intend
subsequently to go : and if the situation they select be not
perfectly adapted to secure them from injuries, it is proba-*
bly, in almost all instances, the best they can discover, for

Choose the I have very often observed, that, when one of my hives was
est place that near]v reacjy to swarm, one of the hollow trees I have men-
tioned (and generally that best adapted for the accommoda-
tion of a swarm) was every day occupied by a small number

and relinquish of bees ; but that after the swarm had issued from that hive,

an intended an(j hacj taken possession of another, the tree was wholly
settlement in a , . , r , . „ , , . ,. , .,

hollow tree, deserted ; whence 1 interred, that the swarm, which would

when a hive is have taken possession of the cavity of that tree, had relin-

offered them. .«,... , , , , . ^ i

quished their intended migration, when a hive was ottered

This prefei- them at home, And I am much disposed to doubt, whe-
ther it be not rather habit, produced by domestication, dur-
ing many successive generations, than any thing inherent
in the nature of bees, which induces them to accept a hive,
when offered them, in preference to the situation they hjave
previously chosen : for I have noticed the disposition to mi-
grate to exist in a much greater degree in some families of
bees than in others ; and the offspring of domesticated ani-
mals inherit, in a very remarkable manner, the acquired
habits of their parents. In all animals this is observable :

but

ence Arises
from-habit.

ON THE ECONOMY OF BEES. £55 •

but in the dog it exists to a wonderful extent ; and the off- Remarkable

. iv • j effects of here-

spring appears to inherit not only the passions and propen- dltary habjt in

sities, but even the resentments, of the family from which dogs.
it springs. I ascertained by repeated experiment, that a
terrier, whose parents had been in the habit of fighting with
polecats, will instantly show every mark of anger, when he;
first perceives the scent of that animal ; though the animal
itself be wholly concealed from his sight. A young spaniel
brought up with the terriers showed no marks whatever of
emotion at the scent of the polecat ; but it pursued a wood-
cock, the first time it saw one, with clamour and exulta-
tion : and a young pointer, which I am certain had never
seen a partridge, stood trembling with anxiety, its eyes fix-
ed, and its muscles rigid, when conducted into the midst of
a covey of those birds. Yet each of these dogs is a mere
variety of the same species ; and to that species none of these
habits are given by nature. The peculiarities of character
can therefore be traced to no other source than the acquired
habits of the parents, which are inherited by the offspring,
and become what I shall call instinctive hereditary propen-
sities. These propensities, or modifications of the natural These habits

instinctive powers of animals, are capable of endless varia- altered and
ii 11 i'ii. i modified by

tion and change; and hence their habits soon become circumstances.

adapted to different countries and different states of domes-
tication, the acquired habits of the parents being transferred
hereditarily to the offspring. Bees, like other animals, are
probably susceptible of these changes of habit, and thence,
when accustomed through many generations to the hive, in
a country which does not afford hollow trees, or other habi-
tations adapted to their purpose, they may become more
dependent on man, and rely on his care wholly for a habi- *

tation ; but in situations where the cavities of trees present
to them the means of providing for themselves, I have found,
that they will discover such trees in the closest recesses of
the woods, and at an extraordinary distance from their hives;
and that they will keep possession of such cavities in the
manner I have stated : and I am confident that, under such Bees never mi-
circumstances, a swarm never issues from the parent hive, grate taJ they

. r have selected a

without having previously selected some such place to retire habitation.

to.

It

<}5(> 0N THE ECONOMY OF BEES.

Bee* ncrt only It has been remarked by Mr. John Hunter, that the mat-

their thighs, ter which bee^ carry on their thighs is the farina 'of plants,

tut other mat- tvith wliich they feed their young, and not the substance with

which they make their combs ; and his statement is., I believe,

perfectly correct: but I have observed, that they will also

carry other things on their thighs. I frequently covered the

decorticated parts of trees, on which I, was making experi-

A compound ments, with a cement composed of bees-wax and turpentine;

of wax and. and in the autumn I have frequently observed a great num-

takenthusby ber of bees employed in carrying off this substance. They

them, detached it from the tree with their forceps, and the little

portion thus obtained was then transferred by the first to the

second leg, by wliich it was deposited on the thigh of the

third: the farina of plants is collected and transferred in the

and used as a same manner. This mixture of wax and turpentine did not,

c«ment. however, appear to have been employed in the formation of

combs; but only to attach the hive to the board on which it

was placed, and probably to exclude other insects, and air

\ during winter. Whilst the bees were employed in the collec-

fhe" bee Very tion of this substance, I had many opportunities of observing

patient as an the peaceful and patient disposition of them as individuals,
individual. r . i i

which Mr. Hunter has also, in some measure notked. When

one bee had collected its load, and was just prepared to take
flight, another often came behind it, and despoiled it of all it
had collecied. A second, and even a third, load was col-
lected and lost in the same manner, and still the patient in-
sect pursued its labour, without betraying any symptoms of
impatience or resentment. When, however, the hive is ap-
proached, the bee appears often to be the most irritable of
all animals; but a circumstance I have observed amongst
another species of insects, whose habits are in many respects
similar to those of bees, induces me to believe, that the rea-
diness of the bees, to attack those who approach their hives,
docs not in any degree spring either from the sense of injury
or apprehensions of the individual, who makes the attack.
Wilsps similar If a nest of wasps be approached without alarming its in ha-
in their habits, hitants, and all communication be suddenly cut off between
those out of the nest, and those within it, no provocation
will induce the former to defend their nest, or themselves.

Buft

0J* THE ECONOMY OF BEES. Q£j

But if one escape from within, it comes with a very different Not sowhen
temper, and appears commissioned to avenge public wrongs, 2^jSS
and prepared to sacrifice its life in the execution of its orders, fight.
I discovered the circumstance, that wasps thus excluded
from their nest would neither defend it nor themselves, at a
very early period of my life; and 1 profited so often, by the
discovery, as a schoolboy, that I am quite certain of the
fact 1 state; and I do not entertain any doubt, though f speak
from experiments less accurately made, that the actions of
bees, under similar circumstances, would be the samer.

Mr. Hunter conceived bees wax to be an animal substarrce, Mr. Hunter
which exuded between the scales of the belly of the insect ; JJ^tngSees
but I am strongly disponed to believe, that it is collected from wax an animal
plants, and merely deposited between the scales of the belly SU s *nce*
of the bee, for the joint purposes of being carried with con-
venience, and giving it the temperature necessary for being
moulded into combs.: and 1 am led to this conclusion, not
only by the circumstance of wax being found in the vegeta-
ble world, but also by having often observed bees employed
in detaching something from the bases of the leaves of plants
with their forceps, which they did not deposit on their thighs,

* A curious circumstance, relative to wasps, attracted the notice of Abundance of
some of my fiends last year, and has net, I believe, been satisfactorily *em*jewasps
accounted for A greater number of female wasps were observed in dif-
ferent parts of the kingdom, in the spung and early part of the summer
of that year, than at almost any former period ; yet scarcely any nests,
or labouring wasps, were seen in the following autumn ; the cause of
which I believe 1 can explain. Attending to some peach trees in my
garden, late in the autumn of the year 1805, on which I had been mak-
ing experiments, I noticed, during many successive days, a vast number
of female wasps, which appeared to have been attracted there by the
shelter and warmth of a south wal1 ; but I did not observe any males.
At length, during a warm gleam in the middle of one of the days, a
single male appeared, and selected a female close to me ; and this wfts
the only male 1 saw in that season. The male wasp, which is readily
distinguishable from the female and labourer, by his long antenna and
sinning wings, and by a blacker and more slender body, is rarely seen out This account-
of the nest, except in very warm days, like the drone bee; and the nests *or*
of wasps, though very abundant in the year 1805, were not formed till
remarkably late in the season ; and thence 1 conclude, that the males had
not acquired maturity till the weather had ceased to be warm, and that
the females, in consequence, retired to their long winter sleep without
having had any intercourse with them.

Vol. XIX— April, 1808. S ' as

258 . MERCURIAL PENDULUM.

as they do (I believe invariably) the farina of plants. I have
also frequently observed the combs of very late swarms to be
remarkably thin, and white, and brittle ; which are circum-
stances very favourable to the conclusion, that the wax is a
vegetable substance, for it would probably be less abundant
during autumn than in summer; and that portion which had
remained on the plants till late in the season would hence
become more colourless by exposure to light, as well as more
dry and brittle than when it first exuded ; but were it an
animal substance, there does not appear any reason, why it
should be more dry and brittle, or less abundant, in the au-
tumn, than in the spring and summer. Thti conclusions of
Mr. Hunter are, however, always drawn with so much cau-
tion, and he united so much skill and science with the great-
est degree of industry, that it is not without much hesitation
and diffidence, that I venture to put my opinion in opposition
to his authority.

Elton, May 4, 1807. T. A. KNIGHT.

III.

Description of a Mercurial Pendulum. Communicated by Mr.
Barraud, of Cornhillj who has made several, and has been
highly satisfied with their performance in the Measure of
Time.

Description of A HE whole length of the pendulum rod, from the rivet

a mercurial that joins the spring to its top, to the end of the screw at L,
pendulum.

fig. 1, PI. VII, is 33A inches, (say 34- inches). The side

pieces of the frame M M are of steel, as thick as the

rod, that is | of an inch, and not less. The top of the frame

H consists of two pieces of steel, each J of an inch thick,

shaped as in the drawing, and screwed over the ends of the

side pieces M M. The inside height of the frame, from E to

A, is 8^ inches, and the inside width between the pieces

M M about 2| inches, so that the cylinder stands \ of an

inch clear of them. The bottom piece N is \ an inch thick

from

ViMtmt FMas. Journal Vol.ATX.Tl.W-p.258.

/.

fig. I

\

o

a

Q

%

o

o

iT

"3

f 1

*

1

ti

ON THE PLANET VESTA. 259

from E to R, and hollowed down to i- of an inch, so as to fit Description of

..... a mercurial

the bottom of the cylinder. pendulum.

L is the bottom of the rod, and one. inch of the end of it is
made into a screw, that has forty threads in an inch. The
ri it K is J of an inch deep, and the diameter of its circle
from m to n is 1T%- inch, having the upper edge divided into 28
equal parts, and figured 0, 1, 2, 3, or at each 7th division.
£ach of these divisions is very nearly equal to l" in 24 hours.

The quantity of quicksilver required is between 10 and 11
lbs. It should fill the glass cylinder up to P, being 6'"4 inches
from the bottom of the glass, measured internally. Fig. 2 is
the cover of the glass cylinder, and fig. 3 the bottom of the
frame, that supports the cylinder, both viewed vertically.

If with this pendulum the clock be found to go right with
the thermometer at 30°, and loses l" in 24 .hours with the
thermometer at 90°> it will be remedied by adding 10 oz. of
quicksilver; and if the reverse by taking out that quantity.

The rod should be -J- of an inch thick, and £ of an inch
wide. The spring should be an inch long, and pretty stiff.

IV.

'Observations on the Nature of the new celestial Body discovered
by Dr. Olbers, and of the Comet which was expected to
appear last January in its return from the Sun. By Wil-
liam Herschel, L. L. D. F. R. S.*

JL HE late discovery of an additional body belonging to the Account of
solar system by Dr. Olbers having been communicated to me lJ)e "^^"ril
the 20th of April, an event of such consequence engaged my 20th, 1807.
immediate attention. In the evening of the same day I tried
to discover its situation by the information I had obtained of
its motion ; but the brightness of the moon, which was near
the full, and at no great distance from the object for which I
looked, would not permit a star of even the 5th magnitude to
be seen; and it was not till the 24th, that a tolerable view

* Philos. Trans, for 1807, P. II, p» 260.

S 2 could

£(j0 ON THE PLANET VESTA.

could be obtained of that space of the heavens, in which our
new wanderer was pursuing its hitherto unknown path.
Looked for. As soon as I found that small stars might be perceived, I

made several delineations of certain telescopic constellations,
the first of which was as represented in rig. 4, PI. VII, and I
fixed upon the star A, as most likely, from its expected si-
tuation andvbrightness, to be the one I was looking for. The
stars in this figure, as well as in all the other delineations I had
made, were carefully examined with several magnifying pow-
ers, that in case any one of them should hereafter appear to
have been the lately discovered object, I might not lose the
opportunity of un early acquaintance with its condition. An
observation of the star marked A, in particular, was made
with a very distinct magnifying power of 460, and says, that
it had nothing in its appearance that differed from what we
see in other stars of the same size ; indeed Dr. Olbers, by
mentioning in the communication which I received, that -
Presumed to with such magnifying powers as he could use, it was not
be an asteroid. to ^e distinguished from a fixed star*, had already pre-
pared me to expect the newly discovered heavenly body to
be a valuable addition to our increasing catalogue of aste-
roids.

The 25th of April I looked over my delineations of the
preceding evening, antl found no material difference in the
situation of the stars I had marked for examination ; and in
addition to them new asterisms were prepared, but on ac-
count of the retarded motion of the new star, which was
drawing towards a period of its retrogradation, the small
change of its situation was not sufficiently marked, to be rea-
dily perceived the next day when these asterisms were again
examined, which it is well known can only be done with
night-glasses of a very low magnifying power.

A long interruption of bad weather would not permit any
regular examination of the situation of small stars ; and it
was only when I had obtained a more precise information
from the Astronomer Royal, who, by means of fixed instru-

* Der ncus planet zeigt sich als ein stern 7\vi?chen der 5ten and f.fen
gnisse, und ist im f.rnrohr, weni'j.sten mit den vergrosserun^en dip icfi
anwenaen kann, \on tinen fixstern nicht zu unterscheldeu.

ments,

ON THE PLANET VESTA. 26 1

♦nents, was already in possession of the place and rate of
motion of the new star, that I could direct my telescope
with greater accuracy by an application of higher magnify-
ing powers. My observations on the nature of this second
new star discovered by Dr. Olbers are as follow.

April 24. This day, as we have already seen, the new ce- Observations
lestial object was examined with a high power; and since a of i:«
magnifier of 460 would not show it to be different from the
stars of an equal apparent brightness; its diameter must be
extremely small, and we may reasonably expect it to be an
r. steroid.

May 2 J. With a double eye-piece magnifying only JS
times, the supposed asteroid A makes a right-angled triangle
with two small stars a b. See fig. 5.

With a very distinct magnifier of 460 there is no appear-
ance of any planetary disk.

May 22. The new star has moved away from a b, and is
now situated as in fig. 6. The star A of fig. 4 is no longer
in the place where I observed it the 24th of April, and was
therefore the asteroid. I examined it now with gradually
increased magnifying powers, and the air being remarkably * t
clear, I saw it very distinctly with 460, 577, and 636. On
comparing its appearance with these powers alternately to
that of equal stars, among which was the 463d of Bode's
Catalogue of the stars in the Lion of the 7th magnitude,
I could not find any difference in the visible size of their
disks.

By the estimations of the distances of double stars, con-
tained in the first and second classes of the catalogues I have
given of them, it will be seen, that I have always considered
every star as having a visible, though spurious, disk or dia-
meter; and in a late paper I have entered at large into the
method of detecting real disks from spurious ones ; it may
therefore be supposed that I proceeded now with Vesta
(which name I understand Dr. Olbers has given the asteroid),
as I did before in the investigation of the magnitudes of
Ceres, Pallas, and Juno.

The same telescopes, the same comparative views, by Similar to

which the smallness of the latter three had been proved, Ce[e;s» Palla3,

r . * and Juno,
convinced

rations.

262 ON THE PLANET VESTA.

convinced me now, that I bad before rae a similar fourth ce-
lestial body.
Described. The disk of the asteroid which I saw was clear, well de-

fined, and free from nebulosity. At the first view I was in-
clined to believe it a real one; and the Georgian planet
being conveniently situate, so that a telescope might without
loss of time be turned alternately either to this or to the ast-
teroid, I found that the disk of the latter, if it were real,
would be about one sixth of the former, when viewed with
a magnifying power of 460. The spurious nature of the
asteroidal disk, however, was soon manifested by an increase
of the magnifying power, which would not proportionally
increase its diameter as it increased that of the planet; and
a real disk of the asteroid still remains unseen with a power
of 636.
Farther obser- May 23. The new star has advanced, and its motion is
direct ; its situation with respect to the two small stars a 6,
is given in fig. 7»

Its apparent disk with a magnifier of 460 is about 5 or 6
tenths of a second ; but this is evidently a spurious appear-
ance, because higher powers destroy the proportion it bears
to a real disk when equally magnified. The air is not suffi-
ciently pure this evening to use large telescopes.

May 24. With a magnifying power of 577 I compared
the appearance of the Georgian planet to that of the aste-
roid, and with this power the diameter of the visible disk of
the latter was about one 9th or 10th part of the former. The
apparent disk of the small star near 0 Leonis, which has been
mentioned before, had an equal comparative magnitude, and
probably the disks of the asteroid and of the star it resem-
bles are equally spurious.

The 20 feet reflector, with many different magnifying
powers, gave still the same result; and being already con-
vinced of the impossibility, in the present situation of the
asteroid, which is above two months past the opposition, to
obtain a better view of its diameter, I used this instrument
chiefly to ascertain, whether any nebulosity or atmosphere
might be seen about it. For this purpose the valuable quan-
tity of light collected by an aperture of 18£ inches directly
received by an eye-glass of the front view without a second

reflection,

OBSERVATIONS OF AN EXPECTED COMET. %63

reflection, proved of eminent use, and gave me the diame-
ter of this asteroid intirely free from all nebulous or atmo-
spheric appearances.

The result of these observations is, that we now are in
possession of a formerly unknown species of celestial bodies,
which, by their small ness and considerable deviation from
the path in which the planets move, are in no danger of dis-
turbing, or being disturbed by them ; and the great success
that has already attended the pursuit of the celebrated dis-
coverers of Ceres, Pallas, Juno, and Vesta, will induce us
to hope, that some further light may soon be thrown upon
this new and most interesting branch of astronomy.

Observations of the expected Comet,

The comet which has been seen descending to the sun, Reappearance
and from the motion of which it was concluded, that we pj^g^
should probably see it again on its return from the perihe-
lion, was expected to make its reappearance about the mid-
dle of last January, near the southern parts of the constella-
tion of the whale.

January 27. Towards the evening, on my return from Seen by Miss
Bath, where I had been a few days, I gave my sister Caro- "ersc e *
lina the place where this comet might be looked for, and
between flying clouds, the same evening about 6h 4Q/> she
saw it just long enough to make a short sketch of its situ-
ation.

January 31. Clouds having obscured the sky till this time,
I obtained a transitory view of the comet, and perceived that
it was within a few degrees of the place which had been as-
signed to it ; the unfavourable state of the atmosphere, how-
ever, would not permit the use of any instrument proper for
examining it minutely. ,

There will be no occasion for my giving a more particu-
lar account of its place, than that it was very near the elec-
trometer of the constellation, which in Mr. Bode's maps is
called machina electrica ; the only intention I had in looking
for it being to make a few observations upon its physical
condition.

February 1. The comet had moved but very little from Described*
the place where it was last night ; and as the air was pretty

clear,
\

264

Compared
with others.

ON THE PLANET VESTA.

clear, I used a 10-feet reflector with a low power to examine
it. There was no visible nucleus, nor did the light which is
called the coma increase suddenly towards the centre, but
was of an irregular round form,- and with this low power
extended to about 5, 6, or 7 minutes in diameter. When
I magnified \6Q times it was considerably reduced in size,
which plainly indicated, that a farther increase of magnify-
ing power would be of no service for discovering a nucleus.
On account of cloudy weather I never had an opportunity
of seeing the comet afterwards.

When I compare these observations with my former ones
of 15 other telescopic comets, I find, that, out of the 16
which I have examined, 14 have been without any visible so-
lid body in their centre, and that the other two had a very ill
defined small central light, which perhaps might be called a
nucleus, but did not deserve the name of a disk.

V.

Observations and Measurements of the Planet Vesta,
John Jerome Schroeter, F.R.S.*

Planet Vesta
has no disk
with a power
of 300,

and an intense
radiating light,
like a star of
the 6th magni-
tude.

The same with
Other tele-
scopes.

By

T our very first observations with magnifying powers of
150 and 300 applied to the excellent new 15-feet reflector,
we found the planet Vesta without any appearance of a disk,
merely as a point like a fixed star with an intense, radiating
light, and exactly of the same appearance as that of any fixed
star of the sixth magnitude. In the same manner we both
afterwards saw this planet several times with our naked eyes,
when the sky was clear, and when it was surrounded by
smaller invisible stars, which precluded all possibility of mis-
taking it for another. This proves how very like the intense
light of this planet is to that of a fixed star.

As the observations and measurements of Ceres, Pallas,
and Juno, were made with the same eye-glasses, but with
the 13-feet reflector, we soon after compared the planet
Vesta with the same glasses of 136 and 288 times magnify-

« From the Philos. Trans, for 1&07, Pa:t II, p. 245.

mg

ON THE PLANET VESTA. £&>

ing power in the 13-feet reflector. In both these telescopes
its image was, without the least difference, that of a fixed
star of the Oth magnitude with an intense radiating light ;
so that this new planet may with the greatest propriety be
called an asteroid. An asteroid.

April 2<3th in the evening at 9 o'clock, true time, 1 sue- Measured,
ceeded in effecting the measurement of Vesta, with the same
power of 288, by means of the 13-feet reflector, with which
that of Ceres, Pallas, and Juno had been made; and when
viewed by this reflector it also appeared exactly in the same
manner. Of several illuminated disks, of 2-0 to 0*5 decimal
lines, which I had before made use of for measuring the sa-
tellites of Saturn and Jupiter, the smallest disk only of 0'5
lines could be used for this purpose; by it the rounded nu-
cleus of the planet Vesta, when the disk was at the distance
of 6iro lines from the eye, appeared at most of the same
size, and I must even estimate its diameter as £ smaller. If
therefore, we attend, not to the full magnitude of the pro- Tts apparent
jection, but the estimation just mentioned, it follows by cal- diameter only
culation that the apparent diameter of the planet Vesta is ^t of'the 4th
only 0*488 of a second, and consequently only half of what satellite of Sa-
I have found to be the apparent diameter ofthefourtl\ salel- turn*
lite of Saturn.

This extraordinary smallness, with such an intense, ra-
diant and unsteady light of a fixed star, is the more remark-
able, as, according to the preliminary calculations of Dr.
Gauss, there can be no doubt that this planet is found in the n is between
same region between Mars and Jupiter, in which Ceres, Mars and Junt.
Pallas, and Juno, perform their revolutions round the sun ;
that, in close union with them, it has the same cosmological
origin; and that as a planet of such smallness and of so very
intense light, it is comparatively near to the earth. This re-
markable circumstance will no doubt be productive of im-
portant cosmological observations, as soon as the elements
of the new planet have been sufficiently determined, and its
distance from the Earth ascertained by calculation.

I/ilienthal, May 12, 1807-

VI.

%66 NEW METHOD OF SLATING.

VI.

On a new Method of Slating, and constructing tlie Roofs of
Houses: by Mr. Lewin Tugwell*.

Principles of ^ JL HE leading principles of Mr. Tugwell's plan are, to
method of* S save s*ate ancJ tmiker, tn»s diminishing the expense of a
roofing. roof; and at the same time to render it secure against the

admission of wind or water. The saving of slate is effected
by lowering the pitch of the roof. This likewise diminishes
the length of the rafters, which at the same time are placed
farther asunder than usual; and besides this the boarding,
usually placed under slates to keep out the wet, is dispensed
with entirely. An additional advantage he observes is con-
nected with his roof. It possesses such superior strength,
as to be capable of sustaining, if necessary, partitions, and
floors connected with them, even down to the ceilings of
the modern enlarged dining rooms, if they be appropriately
constructed and suspended from it; thus superseding the
necessity of the otherwise expensive and complicated con-
struction of spliced beams, ceiling joists, &c, saving tim-
ber and workmanship in these also ; and finally, by thus
combining in a frame the roof, partitions, and floors of a
building, of rendering the whole much more firm and com-
pact, than any mode hitherto used.
His ne\r mode The peculiarities of the mode, and as such necessary to
described. be pointed out, cannot be described, and consist in,

1st. A diminution in its elevation, seen in the beam-raf-
ters A A, PI. VIII, fig. 1, giving an angle of only twelve
degrees from the horizon, whereby both its timbers and slates
will be lessened in quantity in a ratio generally as of three
to four.

2c%. The increased distance of these rafters, as at B B,
fig. 2, one from another, i. e. to two feet. And as, in the
modes hitherto used, they are generally at not more than 15
inches asunder, a farther saving will therein be found of

• Abridged from the Letters and Papers of the Bath and West of Eng-
land Society, vol. XI,

more

0 R

** III i'"

a «

_

r-

NEW METHOD OF SLATING. 267

more than one in three, or as in the proportion of 18 to 11 ; Ne* mode of
and which, together with the diminution in their length bribed. *'
above-mentioned, while they combine in a system of far
greater strength and duration, will incur a saving in the slatr
ing as aforesaid of about a fourth part, and in the raftering
of considerably more than half.

C C, figs. 1, 2, Wall-plates in substance considerably in?
creased ; viz. to six inches square.

D D D, figs. I, 2, Foot-beams, firmly inserted in the wall-
plates, by means of dove-tailed joints, at six feet distance
from each other; one of which joints is seen at fig. 8, laid
open, to display the operation of the wedge; as, should ijfc
inadvertently be driven in on the inside of the plate, and
where floors, partitions, &c. as before hinted, on any occa-
sion, are to be suspended on the roof-timbers, it would ne-
cessarily draw, and derange the whole of the superstruc-
ture *.

E E E, figs. 1, 2, First-piece, of peculiar shape an(J
strength, being two inches thick, and nine deep.

F F, figs. 1, 2, Purloins, or side-pieces, let in, and spike-
oailed to the queen-posts, at right angles with the rafters,
and at equal distances from their extremities.

G G, fig. 2, Plate-rafters, let into the wall-plates at their
lower ends, screwed at their centres to the purloins, and
firmly fastened by an appropriate joint (see fig. 3) to the first
pieces. Thus in these is more distinctly seen the peculiar
and singular stability of the system. As each of the foot*-
beams, together with its sustained and sustaining rafters,
king and queen posts, &c, forms an arch, or rather a series
of arches, of such permanency as not to be subdued, while
their parts remain uncrushed, the wall-plates C G, fastened

* Should it at any time be foreseen that a more than ordinary weight
will be found in floors, partitions, &c, thus suspended on the roof-tim-
bers, it will be only necessary to enlarge the size of the latter, and they
may therein be adapted to any scale required. If, however, there
should be a probability that an alteration in the upper chambers may at
some future peiiod take place, and wherein a removal of the partitions
may become necessary, although it would be far from being impractica-
ble, the method may, notwithstanding, *all things considered, perhaps
not be found the most eligible.

268 WW METHOD OF SLATING,

New mode of to them by dove-tailed joints as aforesaid, constitute, for
scribed. these intervenient rafters, abutments as immovable as those

of the beaftu-rafters themselves ; and which, like those, be-
ing firmly fastened to the purloins F F, at their centres, and
to the first-pieces at their upper ends; while these first-pieces
remain unbent in an upward direction, and the wall-plates
are found immovable outwards, they form, each pair of them,
as permanent an arch as the beam-rafters themselves ; and
thus aiding the latter, they altogether constitute, as afore-
said, a frame of such singular and uniform strength and
stability, as undoubtedly to be capable of sustaining at least
any weight that it may ever be necessary to" lay on it.

H H H, figs. 1, 2, Deal laths, each an inch thick, and
two inches wide, their lower half rabbited for receiving the*
tipper ends of the slates, in depth equal to the thickness of
the latter.

1 1, figs. 1, 2, Slates, nailed nearly at their centres to the
tipper parts of the laths, the nails clenched, and the slates
cemented on both sides to each other with putty, or any
other matter proper for uniting them ; and thereby effectu-
ally excluding rain, wind, driving snow, and all aerial hu-
midity.

K K, fig. 2, Ceiling-joists inserted in the foot-beams after
the usual manner.

L, fig. 2, A portable stage or scaffold for the slater to
work on between the rafters, for keeping at all times under
his thumb a new and appropriate set of simple implements,
(as usefully employed by rational beings in all other matters)
and occasionally, as the work proceeds, to be drawn back-
ward on the ceiling-joists.

M, fig. 1, The slater seated between the rafters on his
stage, with his work before him, and immediately under his
eye.

N, fig. 7, A discharging saw, that, being of proper tem-
per, and having a series of teeth about three inches down on
each side from its point, is occasionally introduced by a
hammer at its heel, and thus removes putty, nails, &c. from
a broken slate ; when a new one, supplying its place, will,
with a little putty under its lower edge to cement it, become
quite as effectual, if not as firm, as the original one. Pro-
bably,

NEW METHOD OF SLATING. <Z6§

bably, the putty having been thus removed by the teeth of New mcdeof
the saw up to the nail, a similar instrument, with however l^ed. *
finer teeth, would more properly apply for cutting off the
latter, when the first might again proceed to the entire sepa-
ration of the slate.

O, fig. 4, A pallet of thin permanent board, that, being
put into a mould for the purpose, receives on its upper sur-
face putty, mortar, or any other proper cement ; and which,
being spread over it with a moistened wooden spatula, or
striker, obtains a uniform thickness (a quarter of an inch
more or less), governed by the depth of the mould, in the
maimer of forming bricks : this is afterward divided into
hull-inch slivers, aud applied on the joints of the slates; as
seen at P, fig. 2.

Q, fig. 5, The mould, of the same breadth on the inside
as the pallet; and which, having an edge vising on three of
its sides more than the thickness of the pallet, gives that of
the cake of cement.

R, fig. 6, A two-edged knife, for dividing and applying
the above slivers of mortar, putty, &c.

S, figs. 1 and 2, a small set or head of iron, about three
pounds weight, to be taken with the left hand, at the driving
of the nails, and pressed hard against their points, thus giv-
ing them an effectual clinching, and at the same time re-
ceiving the impulse of the hammer, so as to prevent all jar-
ring, disjunction, and derangement. Still farther to guard
against this, and to avoid the absurd practice of splitting
the laths with almost every nail that is driven through them,
an appropriate brad-awl, T, fig. 2, with a T head and chis-
sel point, to cut its way across the grain, should be used to
make a passage for the nail, previous to driving it.

While the pressure of every kind of slating on the tim- General defect
bers of a roof is found in all its parts equal, and the power ° r0° b*
of such timbers for sustaining it is, by the modes hitherto
used, very partially applied, and chieBy found in those that
have their lower ends set in its foot-beams ; an idea of a pe-
culiar uniformity and consequent stability in the general
system here recommended, as well as separately in that of
fastening down its slates, will, 1 humbly conceive, impress
itself on every mind open to conviction.

Was

£f$ new Method of slating.

plates should Was the value of these slates duly estimated, howsoever
fuarrte*1 thC P^ente0l,s an(* inexhaustible at their quarries, they might
there, by means of various patterns, saws, drills, rasps, and
other proper machinery, while moist and soft, be formed
into differeutly sized parallelograms, with the greatest faci-
lity, accuracy, and dispatch ; and every slate being made
thereby to retain the utmost regular size its rough dimen-
sions would admit of, much unnecessary waste would be
avoided, and being afterwards regularly classed and deno-
minated by the number of inches in their lengths and
breadths respectively, (as nine fifteens, ten eighteens, &c.
instead of the burlesque terms of ladies, countesses, and
duchesses) they might with much less expense be conveyed
to their respective destinations; and when, whatever the class
preferred, they would be also much more conveniently and
effectively applied, than if of various shapes and sizes; Mill-
stones, grindstones, and indeed all others, if raised at a dis-
tance from their respective destinations, are prudently di-
vested of all superfluous matter and weight at their quarries;
and, but for its claim to exemption from all that is rational,
there is no cause why the same economy may not be used in
the removal of slate.
Thatching From considerations of the great scarcity, and high price

L"ded IS" of timber in general, end consequent necessity for our re-

garding the most frugal use of that article ; also, the im-
mense waste of that ground-work of all our wealth and sup-
port, manure^for our lands, that has, through all ages, front
time immemorial prevailed in the use of thatch; and finally,
from the certain and very great danger of the latter being
destroyed by fire ; the obvious absurdity of using it at all,
wherever a better material may be obtained, one might na*»
turally suppose would evince the propriety of an almost uni-
versal recourse to light thin slates, as a most eligible mate-
rial for roofing in general,
banger of fires I recollect no less than six fires having taken place in my
instanced. native village, from its cottages having been covered with
thatch. One of them was occasioned by sparks from a
forge; another by those from an oven; and three, if not
four, were generally supposed to have proceeded from the
hands of incendiaries. It is observable, that during the

whole

NEW METHOD OF SLATING. 271

whole period of the above only one fire has happened there
under a roof formed of slate : and that in the building of
all houses since, that article has judiciously obtained a pre-
ference. >

With a view to general reformation in the matter, we may Lombardy
observe, that from the universal predilection, during about P°Plar-
thirty years past, for that very beautiful and quick growing
plant, the Lombardy poplar, wisely fostered in all crowded
places, and particularly the metropolis, among other good
purposes, for the purification of the atmosphere, its tine
straight timbers begin now necessarily to be taken down
and brought to market, so that in a short time we may ex-
pect an abundant supply ; and although, being of a very
light and soft texture, no particular use has yet been as-
signed them, there cannot be a doubt of their being ere long
very generally used, at least for inferior buildings ; the pre- Cautions re-
cautions being regarded of felling them always in winter, sPeclmS u-
and when sawn, washing out their saccharine juices, by lay-
ing their scantlings awhile under water; and also giving
them (together with their plank, boards, &c.) extra size, in
proportion to their want of density. The Scotch fir like- Scotch firs,
wise, from the scarcity and dearth of all other timber, and
particularly foreign deals, begins now to be universally em-
ployed. And were the genius and peculiar properties of our
immense tracts of waste lands thought worth attending to,
it cannot be supposed, but that many of them, composed
of light, pervious, blowing sands, and fit for little else,
(such as about Basingstoke in Hampshire, and indeed to be
found elsewhere in too many parts of the kingdom) might
be rendered abundantly productive of this article; and
which also, when felled and sawn, being properly washed,
would be found very generally useful in better erections.
Whenever their long horizontal roots may without obstruc-
tion extend themselves, howsoever infertile, in the common
acceptation, the soil, their growth is generally more rapid
than in land more rich ; but at the same time more close
and impervious*. Nor, it is to be hoped, will the idea be

thought

* There are now lying on the Quay in this town, brought down by
theKcnnet and Avon Canal, many fine trees of larch, with others of

Scotch

iw

Instance in
proof of the
adequacy of
the method.

GEOLOGICAL OBSERVATIONS IN FRANCE, &C.

thought visionary, that were a sufficiency of these article*
thus easily and quickly procured, they might afterwards, by
means of our already numerous and constantly increasing
canals, and other improved modes of conveyance, together
with a proper accompaniment of blue slate, or at least the
factitious red pantiles, be transmitted to every town and
village in the kingdom ; whence the produce of perhaps
richer lands might be remitted in return, and in some degree
commensurate to the expense.

Much also might be done by appropriate and judicious
planning; some houses containing by far more room, and
particularly useful room, than others under the same or a less
quantity of rooting.

The danger of the slates being broken ; and the insuffi-
ciency of the putty or cement, to keep the joints weather-
tight, have been objected to Mr. Tugweirs pian. In answer
to this he points out a house thus covered in upward of three
years ago, which has remained during that time impervious
to wind, wet, or dampness of any kind from the air.

VII.

Heights of various Places in France, $c. ; by Dr. Berger.
Concluded from Vol. XV III, p. 30S.

Sect. IV.

Brief description of some mountains in the department of

Mont-Blanc.

Valley <les JL HE valley des Eornes, the bottom of which is scarcely
Bornc5, higher than the plain of the lake of Geneva, and which is

Scotch and spruce fir, more than forty feet in length, although of less
\ than forty years growth ; they, several of them, square two feet at bot-

tom, and nearly one at the top ; many of the larch, approaching nearer
to parallelisms, are straight, and free from knots; and the lower lengths
of even the Scotch fir cut very good board ; while their tops serve well
Metliod of f°r Coarsti ro°f timbers ; but as the knots hi those dispose their scantlings
feating knotty to warp in drying, care should be taken to soak them immediately from
plants. the saw-pit ; and in about six weeks after, judiciously to stack them from

•'"'the pool, placing the most knotty always at the bottom of the pile, where-
by much of such warping would generally be prevented.

separated

GEOLOGICAL OBSERVATIONS IN FRANCE, &C. 273

separated from it only by the mountains Saleve, Sion, and
Vouache, has for its limits to the south a chain of moun-
tains in the same line as mount Brison, and the direction of
which is parallel to that of the central chain. The course
of the Arve, "and the low mountains that skirt the western
shore of the lake of Annecy, are its boundaries to the north-
east and south-west.

Mr. Saussure has described only the mountains on the Southern
north of this valley. The chain on the south, taken toge- *

ther, is at least 15 miles long-. Its greatest height, like that
of the Jura, is to the south-west. One mountain there, la La Toumette.
Toumette, rises 040 toises above its base. The precipices
of this chain look from the Alps, that is to say, the strata
slope toward them. The limestone that composes them is Silex inter--
compact, including great numbers of imbedded flints, and sPersed m
not unfrequently we meet with calcareous rocks, the tops of
which are completely capped with silex.

Though the mountains that form this chain are all con-
nected together, except that the continuity is occasionally
interrupted by a transverse valley, they have almost as
many different names, as there are parishes at their feet.
The strata are much more regular in the north-east part of
the chains, than in the south-west. Thus the mountains of
St. Laurence display horizontal banks, much resembling
those of mount Saleve ; while at Villaz and Dingy, where
the principal branch of the chain has a perceptible inflexion
to the south', the strata lose their uniform horizontality, and Variation in
this more and more as we approach Tournette, where we the strata.
"see some completely broken, others arched or raised upon
themselves; a character, as already observed, announcing
the vicinity of a transition chain. The back of this chain
toward the Alps falls into the valley of little Bornand, at the
bottom of which flows the river Borne. Over this river is a
bridge more than sixty feet high.

The two principal summits of this chain are Pormonaz Pormonaz.
and Toumette. Pormonaz is nearly in the middle of the
chain, and rises 540 toises above its base. The first part of
the ascent is through a very thick wood, from which, after Thi k wood.
a journey of two hours and half, you enter into rich pas- pasl
tures, bounded on all sides, except to the north-east, by

Vol. XIX— April, 1808. T cliffs

274

GEOLOGICAL OBSERVATIONS IN FRANCE, &C.

cliffs more than 180 toises high. In these meadows, which
form a natural amphitheatre, are huts, where you may spend
the night on occasion, and whence there is a pleasant view
of part of lake Annecy and the surrounding country. From
this station you gain the summit of the mountain in an hour
and three quarters. Nothing can be more dreary than the

Extensive baie top of mount Pormonaz. Figure to yourself a vast flat of

flat* ^imestone rock, perfectly bare and destitute of vegetation,

intersected by clefts in every direction, like the table-land
of mount Plattet, and you will have a just idea of it. Here
and there at the bottom of these clefts are seen the dry
trunks of some lifeless firs, the brown colour of which forms
a striking contrast with the whiteness of the rocks amidst
which they are found.

Flints. In no part of the chain did I find nodules and caps of

flints so abundant. The analysis of one of these nodules
gave me 0*87 of siliceous earth : yet when reduced to pow-
der an acid excited a slight effervescence in it, from a small
quantity of calcareous earth, either forming a constituent
part of it, or from which the surface could not be completely
freed.

Touraette. From the summit of Pormonaz Tournette appears to ad-

vantage. It is seen directly south, and exceeding in height
most of the mountains around it as much as Mont Blanc
surpasses the summits in its vicinity.

Ascent to it. Tournette may be ascended by the way of Talloires, but
more easily by that of Thones, a small but very ancient
town, now the chief place of a circle, which is seated at its

Th6nes. east foot. This town is built in a very narrow valley, which

on this account enjoys a warmer temperature than the larger
vale, as is evident from the plants it produces.

From Thones you proceed along the bottom of this val-
ley for half an hour, then cross a branch of the Siere on a

Clefs. wooden bridge, and reach the hamlet of Clefs. Thence

the road continues through a wood of beech and firs, not
very thick, to about one third the height of the mountain.
At this place are a few summer huts. The first time I

JRecent glacier, ascended Tournette, which was in 1799* I found on the
12th of August, some distance above these huts, a cake of
frozen snow, several feet thick at bottom, the only place

where

GEOLOGICAL OBSERVATIONS IN FRANCE, &C. 275

\rhere its thickness could be estimated, and extending up
the acclivity of the mountain quite to its summit. The pre-
ceding winter having been severe, so much snow had fallen,
that the heat of summer had not been able to melt it, a cir-
cumstance uuheard of before, for the oldest inhabitants
could not recollect, that the snow had ever remained longer
than the end of June. I conceived this mass of frozen
snow might prove the nucleus of a glacier of the second
order*: and in fact the following year, when I returned
thither in July, I found the snow, far from having dimi-
nished, had rather increased, so that the recent production
of a glacier on this mountain appeared to me very proba-
ble.

On approaching the summit the stone assumes a fissile
character, which it had not below ; and we meet with dode-
caedral calcareous spar finely crystallized, and several frag- Spar,
ments of gritstone, of which there is a stratum 116 toises Grit. *
above the level of the sea. I did not perceive any nodules ^0 fljnt#
of silex, which are so common on mount Pormonaz. The .
loftiest point of Tournette is a very remarkable rock. It Singular rock.
is nearly circular, 94 feet high, and 145 in diameter, stand-
ing alone on a point of the ridge that forms the summit,
and cut perpendicularly nearly alike^on every side. There
is no getting to the top of it, but my means of steps cut in
the rock on the north-east. It is no doubt from this rock,
standing there like a sentry-box, and seen from all the sur-
rounding country, that the mountain received its name.
The prospect from it is very extensive and interesting. To Prospect from
the east it takes in the centre of the grand chain, and all ll*
the secondary ones attached to it in succession: to the south-
east the mountains Tarenteuse and Maurienne: to the south-
west those of the department of the Isere : the chain of
Jura to the north-north-west: and the lake of Geneva to

* Mr. Saussure first distinguished the glaciers into two kinds. The Glaciers of tw*
first are included in the bottoms of the high valleys, almost all in a kinds,
transverse direction, that terminate at bottom in the low longitudinal
valleys, while at top they form grand culs-de-sac surrounded by inacces-
sible rocks. Such are those that terminate in the valley of Charnouni.
Those of the second kind are not included in valleys, but spread over
the slopes of lofty summits.

T 2 the

£76 ©EOtOGICAL OBSERVATIONS IN FRANCE, &C.

the north. Beneath your feet you have a bird's eye view of
the lake of Annecy, and the fine plains around it: and
westerly, toward the Lyonnois, the view extends very far, as
there is nothing to interrupt it.

Another road. The road by way of Annecy and Talloires is much more
laborious. The ascent from Talloires is very steep, and not
free from danger. In the neighbourhood of that town is a

Vineyard. fine vineyard, formerly belonging to a convent of Benedic-
tines there ; and the road to it from Menthon is shaded by

Chesnuts and walnut and chesnut trees. The mountain itself is very rich

walnuts. m piantSj whichever way you ascend it.

The following table exhibits the heights of the different
places that have been mentioned, in fathoms and thousandth
parts above the level of the sea, as calculated from the height
of the barometer, both according to the formula of Deluc
and that of Trembley, with the mean temperature by Fah-
renheit's thermometer, and the time when the observations
were made.

The heights of some of the principal points, as given by
Deluc, Pictet, and Saussure, are also added.

TABLE

GEOLOGICAL OBSERVATIONS IN FRANCE, &C.

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2g£ et/LTtmt of- the fopfy FOR on,

VIII.

On *fo Cultivation of the Poppy. By T. Cog aw, M. D**
Gentlemex,

A

LTHOUGH the ardour with which the British nation
pursues whatever promises to be of public utility, is perhaps
unequalled by any other, and certainly exceeded by none;
yet there is one subject which has hitherto been permitted to
Cultivation of escape our attention, and in which several nations upon the
the poppy neg- continent can not only boast of their superior policy, but are
already enjoying considerable advantages from it; I mean the
cultivation of the poppy to a great extent for the benefit of its
oilt as an article of food, and for other useful purposes.
Objection to It. It will doubtless be remarked, that we ought not to ascribe
the neglect of it as an article of food to inattention altogether,
but to a superior caution, as the narcotic quality of the
poppy renders it totally unfit to be taken inwardly. This, it
is allowed, is, in appearance, a very formidable objection;
and as it respects the lives of multitudes, it ought not to be
treated with levity: the objection itself, and the argument
from analogy on which it is founded, ought to be completely
confuted, before the article can be recommended to the com-
munity in this novel point of view.
Answer to this We might observe that the objection is solely founded
objection. upon very slight and imperfect analogy. It assumes, that,
because some parts of a plant are noxious, the whole must
be equally noxious. But this assumption may be confuted
in numberless instances. Daily experience testifies, that dif-
ferent parts of plants possess not only different, but opposite
qualities. Oranges and lemons, which are used in profusion,
possess juices that are both palatable and refrigerating; but
these are enclosed in a rind, the essential oil of which is ex-
tremely acrid and stimulating: and it is well known that the
bland and nutritive tapioca is the produce of a tree the roots
of which are highly poisonous. In this case, therefore, the ar-

* Papers of the Bath and West of England Society, vol. X, p. 331.

CULTURE OF THE POPPf FO* OIL. g85

Aliment from analogy may be considered as a very proper mo-
tive for caution; but if it advances farther, it degenerates
into a pernicious prejudice.

There have been, however, many incidental circumstances The oil has
which have had a partial influence in removing these preju- J?eeri used
dices. It is well known, that compounders of medicine have injury,
made a very liberal use of the seeds of poppies, as substi-
tutes for tjie oil of sweet almonds, without the least detri-
ment to the patient. They have sometimes imputed to it
additional virtues, from its being supposed to possess narcotic
properties. But that they have erred in their hypothesis is
plain, from the practice of many individuals, who have made and the seeflg
the seeds of poppies a common article of food*. also.

But it will be the principal object of the following paper
to inform the inhabitants of this country, through the me-
dium of your publication, that the above objection has been
repeatedly advanced and repeatedly confuted; that experi- Cultivated ex-
ments, first made with a degree of caution, have finally re- Pensively
moved prejudices long and inveterate; and that the white Q\\%
poppy (papaver hortense scmine albo) is cultivated to a very
great extent in Dance, Brabantr and Germany, and more re-
cently in Holland, chiefly to extract the oil from its seeds;
which is found not only to be salubrious, but to be peculiarly
delicate in its flavour. It is now become a considerable ar-
ticle of commerce : the oil of a superior quality, for the use
of the table, and the inferior for manufactories and various
other purposes. It is produced not only with considerable
profit to the cultivator, but also to the merchant and con-
sumer.

As it is natural to imagine, that the prejudices against the Prejudice*
common use of poppy oil for culinary purposes will be very against it,
general, since they are apparently sanctioned by prudent cau-
tion, it is not expected that the most positive assertions,
founded upon the experience of strangers on the continent,
would be sufficient to remove them. But a circumstantial
narrative of a contest which has already taken place; and succeSsfuUr
the final triumph of experience over the opposition lounded combated.

* See Prosper Alpinus, lib. iv, cap. i. Geofrey Mat. Med. torn, ii, p .
715. Lewis's Materia Medica, Article Papaver Album.

on

£$4 CULTURE OF THE POPPY FOR OIL..

on analogous reasoning; and a particular statement of the
advantages which have accrued to the cultivator, merchant,
and consumer, may -perhaps attract the attention of some
agriculturists in our own country, who may thus be en-
couraged to make similar experiments: and as the issue must
be the same, they will be able to produce absolute demon-
stration, that the oil is totally destitute of the noxious quali-
ties, that have been ascribed to it; and finally convince the
public, that it may become a cheap and useful substitute for
the olive oil, and a very beneficial article of commerce.
Hiseand pro- For this purpose I shall state to the agriculturist a succinct

gress of its account of the rise and progress of the cultivation of the
cultivation. . . , , ,- , , ,

poppy, in order to express the oil from the seed; the manner

of cultivating it, and the emoluments which have been re-
ceived by the cultivator, from authentic documents in the
Dutch and German languages which are in my possession.

Oil of poppies. In the year 1798* the Society established at Amsterdam
for the encouragement of agriculture, being informed that
the oil of poppies was cultivated in several parts of France,
Flanders, and Brabant, thought it an object of sufficient im-
portance to make more particular inquiry; and they learned
from indubitable authority, not only that it was generally

Made in large used in the place of olive oil, but that several thousand casks

grammes and 0f jt were exported annually, a large quantity of which was
imported into Holland, and sold under the name of olive oil,
or mixed with it in considerable abundance; and they appealed
to several merchants who were members of the Society for
the truth of this assertion, without being contradicted.

Premiums pro- These facts induced the Society to propose three premiums,

posed by a So- consjgj;jng 0f a silver medal and ten ducats each, which were

ctety at Am- &

sterdam. divided into the three following classes.

The Jirst to the husbandman who should sow not less than
half an acre of a clayey soil with poppy seed; the second on
a sandy ground; and the third on turf or peat land.

They also offered to the person who shall have cultivated
the largest quantity of ground, on the two first species of
soil, in the most masterly and advantageous manner, a gold
medal, value fifty ducats, or that sum in money, in lieu of
the above premiums.

The

CULTURE OF THE POPPY FOK OIL. g85

The candidates were to give an accurate statement of the
quantity of seed sown per acre; the time of sowing, and of
gathering the poppies; the quality of the soil; the manner
of procedure in every part of the process; the quantity of
oil produced, and the total of the expenses.

In consequence of the above proposals, in the year follow- Clairaantfor
ing (1799) Mr. P. Haak became a claimant; sent in satis-
factory specimens of the oil produced, accompanied with
testimonies from two respectable physicians, that upon expe-
riments made, it fully appeared that the use of the oil was not
in the least prejudicial to the human constitution; and that
the oil-cakes were very wholesome and nutritive food for
cattle.

The Committee appointed to receive this report not only
expressed their entire satisfaction at the attestations of the
physicians, but they laid before the Society at large an
account of the proceedings which had taken place in France,
upon the interesting question concerning the noxious or "sa-
lubrious qualities of the poppy oil, in the following Narrative,

So early as in the beginning of the seventeenth century, Proceedings in
the oil of poppies was produced in such large quantities, that ^"in th 3^
it gave rise to great and lasting contentions, which rose to good or bad
such a height, that the government was desired to interfere, <lualmes °f
and appease the contending parties; either by authorising
the use of this oil, or totally to prohibit the consumption,
according as experiments should decide whether it contained
the noxious qualities ascribed to it, or not.

The opposers urged the objections already stated : they as- Arguments
serted, that as the capsulum or poppy-head contained aSainst*^
juices highly narcotic, this must also be the case with its
seeds ; that the frequent use of the oil extracted from them
exposed the consumer to all the dangerous consequences
arising from the too liberal use of opiates; and that they
would finally obtund the faculties of the soul ; that the oil
was of a drying quality, for that it was upon this account it
became peculiarly useful to painters : they therefor* implored
government to confine its uses to this object.

The advocates maintained that no -proofs existed of these Answered by
pernicious effects; but on the contrary, experience testified facts*

that

286

CULTURE OF THE POPPY FOR Ott.

Used by the
ancient Ro-

Cerreets the
rancidity of
•live oil.

Consequence
of a scarcity
of olive oil.

that the seeds were peculiarly nutritive both to men and (Tat-
tle; they asserted that the ancient Romans, concerning whose
mental powers there could be no doubt, were accustomed to
mix the oil and meal of the poppy seed with honey, and
have it served up as a second course at their tables ; and that
it was on account of its nutritious qualities so well known to
the Romans, that Virgil gives it the title of ve&aim,food, by
way of preeminence; and that the peculiar qualities of this
oil rendered it a desirable object of cultivation; and that taste
was delicate and pleasant, somewhat resembling that of the
hazel nut; that it continued in a fluid state, exposed to a
much greater degree of cold than was required to congeal
the olive oil ; that it contained a larger quantity of fixed air,
which preserved it a longer time from being rancid; that in
these particulars it not only approached to the finest oil of
Provence* but it mitigated the disagreeable taste which that
oil acquired by length: of time; and that the poppy oil de-
cidedly deserved a preference to every other oil expressed
from seeds, whether nut, almond, or beech ; which, tho' they
yielded large quantities, soon became rancid : and as7 there
was no appearance of its being pernicious in the more exten-
sive use of it, so valuable a product ought not to be confined
within the narrow bounds of the painter's use.

Things were in this state, without any prospect of accom-
modation between the parties, when the severe winter of 1709
overtook the combatants. This damaged the olive, nut, and
almond trees to such a degree, that there was a great scarcity
of their oils; and they were obliged to have recourse to the
substitutes, beech and rape, &c. But it was soon perceived,
that these were far inferior to the oil extracted from the red,
white, or brown poppy, which had a much nearer resemblance
to the small portion of the olive oil which the winter had
spared. This was consequently mixed with the olive oil in
the proportion of 4-, %, \, without the least opposition. But
when it was attempted to sell the poppy oil in its pure and
unmixed state, the opposition became so violent, that the
Lieutenant-Gene ral of the police of Paris resolved, in the
year 1717, to order the medical faculty of that city to make

the

CULTURE OF THE POPPY FOR OIL. £87

the strictest examination concerning this subject, and deliver

in their report.

The faculty appointed forty of the most celebrated prac* Report of a

titioners in medicine as a committee of inquiry, who were SwrSSSito

witnesses to various experiments accurately made, and whose its fayour.

report was expressed in the following terms : " cum sensuissant

doctores, nihil narcotici, aut sanitati inimici in se continere,

ipsius usum tolerandum esse existimarunt ;" that is, they were of

opinion, that as there is nothing narcotic or prejudicial to

health contained in the oil, the use of it might be permitted.

But this decision was unsatisfactory ; and popular clamours Popular eta-
, . , , „ . , .t mours against

determined the court of justice to pass a decree in the year it>

1718, whereby the sale of poppy oil, whether mixed or un-
mixed, was prohibited, under a fine of three thousand livres
for the first offence. Notwithstanding this prohibition, the
sale of the article was clandestinely encouraged and gradu-
ally increased until the year 1735, when the court issued a
severer decree, enjoining it upon superintendants appointed,
to mix a certain quantity of the extnact of turpentine to every
cask containing lOOlbs. of this oil; of which not less than
two thousand casks were consumed in Paris alone. This at-
tempt to render the use of it impracticable, had no other
influence than to annihilate the public sale of the article,
but the secret demand for it increased : till at length, in the
year 1773, a society of agriculture undertook to examine
with the closest attention all that had been alleged, either by
writing or otherwise, for or against the general use of this oil,
Experiments were repeated in the presence of the most dis-r
tinguished chymists, with the same result, and the Society
presented a petition to the Minister of Police, setting forth
the great advantages that would accrue both to commerce
And agriculture, by reversing the prohibition.

This petition was put into the hands of persons who vended
various kinds of drugs, and who had, as a body, opposed the
subject of it, with orders to state all their objections to the
medical faculty ; by these means the faculty became masters
of every thing that was urged in the debate. They again y\^ determi-
made several experiments in the year 1776, and finally con- nation in its
firmed the decree of the faculty issued in 1717, declaring avoar*

that

£gg CUXTURE OF THE POPPY FOR Oil.

that the oil of poppies was not injurious to health, that it did
not contain a narcotic power, and that it might be recom-
mended to general use with the utmost safety. The medical
faculty at hide had also made a similar declaration in the
j car 17/3. From that time to the present the cultivation of.
the poppy has not met with any formidable opposition; and
has increased to such a degree both in Fiance and Brabant,
that they have been able to export a considerable surplus, to
the great advantage of the husbandman, as well as the mer-
chant: and in seasons of scarcity it has been found of the
most essential service, in all cases where the use of oils was
Cilusedby required. In the northern parts of France, it was used by
soap-boilers, soap-boilers, as a substitute for other oils, which were ex-
Oil cakes for tremely dear: and in Brabant the oil-cakes are constantly
catlle# used as food for cattle with obvious benefit.

These facts being established, the Committee of Agricul-
ture in Amsterdam proposed the premiums above-mentioned,
in order to ascertain whether the experiments made would
authorize the cultivation of the article upon a large scale;
whether the soil and climate of Holland were beneficial to its
growth ; whether the quantity or quality of the oil would be
similar to the product of France and Brabant ; whether the
profits would indemnify the husbandman for giving it the
preference to other crops ; whether the oils could be afforded
cheaper than those in common use ; and to what purposes
either in the arts or manufactories it might be applied.

Deeming it possible, that the narrative of a contest which
subsibted the greater part of a century, and in which the ad-
vocates for the internal use of the poppy oil were uniformly
triumphant, may have some influence in destroying our own
prejudices and apprehensions, respecting the pernicious
Particulars of quaMty ©f this oil, I shall now proceed to state, in as concise
culture. a manner as perspicuity will permit, the most interesting

particulars respecting its culture; selected from various fo-
reign publications upon the subject.
Soil. SoiL The poppy may be cultivated with success on vari-

ous kinds of soil. It has been tried on a rich black soil,
peat-ground, and sandy heaths, and been productive. Those
lands in which the wild poppy abounds the most, are obvi-
ously

CULTURE OF THE POPPY FOR OIL. g8<)

ously most congenial to its nature. The richer the soil, and
the clearer from weeds, the larger will be the crop. It is not
so advisable, however, to manure for the poppy, as for the Management,
crop preceding it, as it is more exposed to injury by weeds.
Hence it succeeds the best after carrots, cabbage, potatoes,
&c. The land was generally prepared by the spade, ns in
planting potatoes; and the finer it is worked the greater the
advantage. But when it is cultivated to a great extent, they
use the plough. The seed has generally been sown broad-
cast, the plants thinned, and weeded afterwards, as in the cul-
ture of turnips ; but in drills it is sown about six or eight in-
ches distant in the rows, which has been strongly recom-
mended ; experiments upon a small scale having manifested a
superiority in this mode.

The Kind and Quantity of Seed. Although the white What kind
poppy has been chiefly used in Trance and Brabant, under the
supposition that it produced the finest oil, yet it has been
found that various other kinds will answer the purpose as
well. It is even asserted that the blue poppy, while it yields
the largest quantity of seed, is in no respect inferior in the
quality of the oil. Admiral Kingsbergen, whose private vir-
tues render him no less a favourite with his countrymen, than
his skill and courage as a naval officer, instituted an experi-
ment with different kinds of seeds in the same soil, and he
could not perceive any difference in the quality of the oil,
while the seeds of the blue poppy yielded considerably more.

The quantity of seed generally used in the broad-cast has Quantity of
been after the rate of 2 lbs. to an English acre. In drills seed*
a less proportion has been used.

Time of sowing. This is from the middle of March to the Seed time,
middle of April. If it be sown much earlier, it is more likely
to be choked by weeds; if later, the harvest will be thrown
deep into the autumn ; and unless the weather be unusually
favourable, the seeds will not ripen kindly.

Weeding, As soon as the plants appear about two inches Weeding ne-
above the ground, they must be carefully weeded and thinned, cessary.
till they stand about seven or eight inches from each
other. The weeding to be repeated as often as it shall appear
necessary.

Vol. XIX— April, 1808- U Harvest.

290 CULTURE OF THE POPPY FOR OIL.

Method of har- Panesfr In the beginning, middle, or end of August, ac-
cording as the time of sowing has been earlier or later, and
the season propitious, the seeds are ripe for gathering the
poppy heads. Several methods have been recommended to
harvest the crop. At first, the heads or balls were broken off
from their stems, gathered together in large quantities, and
deposited in a barn, or any other convenient place, in large
heaps, in order to dry them. This method was not only te-
dious but injurious; some of the balls becoming musty, com-
municated a disagreeable taste to the seeds, and consequently
to the oil. Mr. Poske, of Zell, in the electorate of Hanover,
prefers the following method. He draws the entire plants
out of the ground ; binds a sufficient number of them at each
extremity, and places them against each other in the manner
of wheat-sheaves ; and lets the whole remain in the field for
eight or ten days, until they are perfectly dry. It was cus-
tomary to cut open the capsulum with a, knife; he prefers
hacking it in two or three places with a bill-hook, and asserts
that one person may in this manner do more work than ten
times the number of hands in the former manner; and that
the seeds are more easily evacuated from their cells. But
the most convenient and expeditious method is to cut off the
poppy heads, as they stand in the field : the reapers having
an apron before them, tied up at the corners. In this they
collect as large a number as is convenient, and empty them
into bushel baskets placed upon a cloth ; by which a consider-
able quantity of seed is saved. The heads are afterwards put
into corn sacks, in a competent number to be trodden by
men or children in sabots, or to be bruised by a mallet or flail:
by these means the heads are confined from flying from the
stroke, and the seeds preserved from being scattered, and
afterwards passed through a sieve of a proper size.

Extraction of Tn extracting the oil, it is of the utmost importance that the
mill,press, and bags be perfectly clean and pure. New hags are
necessary, as those used for linseed, rape, or any other seed,
will communicate aiv unpleasant taste to the oil. It is ad-
viseable to extractjthe oil as soon after the harvest as possible,,
as the seeds will yield a larger quantity than if deferred till
the spring.

The

CULTURE OF THE POPPY FOR OIL. 2Q 1

The first oil is destined for the use of families. This is Two kinds of it.
<s>M-drawn9 as any degree of warmth injures the flavour. Af-
ter as much is extracted in this manner as possible, a con-
siderable quantity of an inferior quality is obtained by heat-
ing the cakes, and pressing them a second time.

The oil expressed must remain for the space of five or six Management
weeks before it is used, that it may deposit in a sediment a ° lt"
kind of milky substance that is mixed with it. It must then
be poured into another vessel ; and this should not be per-
fectly closed at first, but the opening be covered with a
linen cloth, or a pricked bladder, that certain exhalations
may pass. Nor should the oil be immediately used after the
process is finished, as it continues to improve for a consider-
able length of time.

That which is first expressed is of a pale colour; is pecu- The best oil.

liarly bland and soft, has a flavour approaching to that of

the almond oil. It is used for sallads and other domestic

purposes, either alone or mixed with olive oil. Should the

latter be stale or rancid, it will be considerably improved by

a mixture of recent poppy oil. It is not asserted that this Superior to the

oil may be placed in competition with Provence or Italian c°m™°n °hve
.,„... i i • • • ii- oil of the shops,

oils of prime quality ; but that it is superior to the olive oils

sold in shops, being often used to improve their quality.
May I not add, that the inhabitants of this country are some-
what prepared for the culinary use of this oil, by being al-
ready accustomed to its taste, though without their know-
ledge. For since it has long been imported into Holland,
and used without suspicion, we cannot suppose that the mer-
chants of this commercial nation are totally strangers to the
commodity*.

The

* We are told by Mr. C. A. Fisher, in his Letters written during a
Journey to Montpeilier, in the year 1804, " that the oil of Provence, which,
on account of its purity, mildness, and fine flavour, is famous all over * *'
-Europe, is exported to Italy in large quantities, and was formerly ex-
ported to many distant countries. But since the hard winters of 1789,
and the following years, so many olive trees have been frozen, and dur-
ing the Revolution so few planted, that Aix (which was the principal
seat of its traffic) has now entirely lost its first and most lucrative branch
©f commerce.

U2 Two

292

Inferior useful
for lamps, and
other purposes.

Cakes equal to
linseed for cat-
tle.

Stems make
fodder or ma-
nure.

Frofit of thif
culture.

Produce of
seed.

CULTURE OF THE POPPY FOR OIL.

The second-drawn oils are of a deeper colour, and are ap-
plicable to all the purposes of the more common oils. This
may even be used as lamp oil ; and it is alleged, that it does
not give off so large a quantity of smoak, and emits a
brighter flame.

The oil-cakes are peculiarly serviceable for feeding and
fattening of cattle: being deemed equal to linseed cakes.
All cattle are very fond of it, and eat it with eagerness^
This is the constant use of it in Brabant. The stems art
sometimes used for fodder, containing a considerable quan-
tity of nutritive oils ; or mixed with stable dung and other
manures, they enrich their quality.

Expenses) produce) and profits* Concerning these arti-
cles it will be necessary to be particular, though it is some-
what difficult from a difference in the current coins, mea-
sures, &c. I shall state the result of experiments made on
three hundred roedenf , about one acre, of a sandy soil, and
three hundred roeden of a heavy peat, made by a claimant
named S. N. Van Eys. The peat land being low and hu-
mid, he was obliged to make deep trenches between the
beds. The harvest on this soil was later, the poppy heads
were not so dry when gathered, and they shrunk considera-
bly in drying. There was so small a difference in the quan-
tity of seed from these different soils, that no important
preference could be given. The sand ground yielded in
this instance rather less than the peat land. As the quality
of the seeds appeared perfectly similar, he mixed the whole
produce together, when he sent them to the oil mills.

The produce of the sand ground rather exceeded 13 sacks,
that of the vecn or peat land, was about 12 sacks: together
they made 25 sacks, 1 bushel of seed. These yielded oil in
the following proportions : —

Two inferences may be drawn from the above information. Our best
oils, though imported from Italy, are probably of the growth of Pro-
vence ; and it is still more probable that the inferior sorts could not be
afforded, even at the present price, v ithout a larg- mixture of iho poppy otf.

f The English statute acre is 160 square perches; and the Dutch
morge, consisting of GOO roeden, is equal to 300 square perches : so that
the difference between a Dutch morge and two acres, is as 300 to S20,
the former being only 20 perches less than two acres.

23 sacks

CULTURE OF THE POPPY FOR OIL. ££3

Mingles*. Cake*
<23 sacks which were pressed cold gave •• 271 834 Of oil and

2 sacks warmed » 29 56

834 cakes warmed and pressed gave 73

cakes.

Total oil 373 890

Cakes diminished in a second pressure to
726 minus, 108

Total of cakes 732

Mr. Van Eys remarks that poppy oil of a very inferior
quality is sold retail at one guilder, or 1*. \0a\ per mingle
or quart, and that mixed with olive oil at a much higher
price. However he estimates the cold-drawn at \6d. only,
and the second sort at 14c?. per. mingle. The cakes are va-
lued at 10 guilders, or 19*. per 100. His receipts stand
thus : —

271 Mingles, (cold drawn) ? __ k . ,.
' * v ' >F. 216 16
at lod. )

102 ditto, (warm) at I Ad. 7 1 8 ^

782 Cakes at 10 f. per 100 .... 78 4

Total • • F. 366 8 • • £33 0 8

STATEMENT OF EXPENSES. Exneoses.

To digging, &c. 600 roeden, ? F

at 1 f d. per r. )

Seed, sowing, weeding, &c •• • 42 19
Harvesting, beating out seed, r „

&c... )

Pressing out the oil, bags, &c. 63 8

Total • -F. 207 0..£l8 14 Q

Receipts • . ' F. 366 80- £33 0 8

Expenses 207 00- 18 14 0

Total of Profit F. 159 8 0 £14 6 8

This degree of profit upon nearly two acres does not at Observation*,
first appear to be encouraging: particularly if we take into

* A. Mingle is about two pints.

con-

£94 CULTURE OF THE POPPY POR OIL.

consideration rent of land, taxes, &c., winch are not men-
tioned in the statement. Mr. Van Eys has remarked, that
the expenses attendant upon pressing out the oil, in this
first essay, were considerably greater than would be experi-
enced in the usual course of business. We may also notice,
that the preparation of the ground by manual labour crea-
ted a difference in the expense, that would prove an equiva-
lent at least to the value of land and contingent charges.
But what is of much greater moment is the very low price
of the oil, as stated in the above account. That of an infe-
rior quality being valued at somewhat less than 5s per gal-
lon; and the superior at less than 5s. 6d.; whereas common
lamp oil is with us sold for 6s. per gallon, and sallad oil of
no extraordinary quality at 2s. 6d. or 3s. per pint, or l/. or
4s. per gallon.

It clearly appears from these facts, that Is. 6d. per pint,
or 12s. per gallon for the prime article wholesale, and at least
4s, per gallon for the inferior sort, would be an advantage-
ous price for the purchaser, who would be able to retail it
considerably under the current prices of these articles.
Estimate to the Accordiug to this estimate, the receipts upon 271 minge-
mer.b ' ^en or °iuarts °f tne co/c?-drawn would amount to about 40/. ;

upon 102 quarts of the inferior, to 5/. ; and upon 782 cakes,
at l/. per 100, to 7/. 10*. ; total 52/. 10s. for one morge, which
would be after the ratio of 26/. 5s, per acre. The expen-
ses not exceeding 10/. per acre, would yield a clear profit of
1/. 16/.

Should the oil of superior quality answer the description
given of it, and be more palatable than the olive oil in com-
mon use, \2s. per gallon would perhaps be too low an esti-
mate for our national character. For observation authorizes
me to assert it as a serious fact, that nothing has a greater
tendency with us to depreciate articles of nutrition, especi-
ally if they approach to luxuries, than to render them too
cheap. And although we complain universally, that such
articles are extravagantly dear, we almost as universally sus-
pect or despise whatever may be purchased at a very reason-
able price. But as retailers are both able and willing to
obviate this objection, the above statement for the vendor in
wholesale may be permitted to remain.

But

CULTURE OF THE POPPY FOR OIL. 29«5

But there is another important point of view in which this l^^^at
suhject may be considered. Successful attempts have lately opium to be
been made to procure opium from the poppy, in no respect obtame •
inferior to that imported from the East*; and it is asserted,
that although it may be afforded at a very inferior price, the
product would afford ample profit to the cultivator. As the
opium issues from the rind, and the seeds have been proved
not to partake of its narcotic properties, an important in-
quiry presents itself, whether the poppy may not be cultivated
with a view to both articles? This can only be determined by
solving another question, will the incisions made in the green
and unripe capsufum, and the exudation of its juices, prove inju-
rious to the seeds in this advanced state of its growth ? The
argument from analogy, which is the only mode until we can
obtain facts, appears to favour the negative of the question ;
not only as there is no immediate correspondence in the
qualities of these two parts of the same vegetable, but as many
experiments have proved, that by checking the growth, or
weakening the vegetative powers of one part of a plant, they
are increased and improved in another.

Desirous of obtaining some information concerning this Experiments,
interesting subject, I sowed, in the year 1804, about half a
lug of garden ground with the white poppy seed; and when
the heads were advanced to a sufficient state of maturity, I
scarified the external surface of one portion of them with a
penknife, suffering the others to remain entire; and though the
exudations were very considerable, there was no perceptible
difference in the colour, taste, or size of the seeds; except-
ing where the incisions passed through the whole integument,
which frequently happened from the imperfection of the in-
strument, and my inexpertness. The seeds which lay near-
est to the openings were discoloured by the admission of ex-
ternal air; but the taste of the seed was not injured.

This little experiment served to convince me, that the seeds Rats,mice,iind
of the poppy are peculiarly grateful to birds, rats, and mice. *?*jfjj|
• The first dexterously made large holes in the lower surface of

* See Transactions of the Society instituted at London, for the En-
' couragement of Arts, &c. on the mode and advantages attending the
cultivation of Opium.— Vols. 14, 15, 1G, 18.

the

£Q6 culture of the poppy for oil.

the ball, through which the seed fell to the ground; and they
tluis materially injured a considerable portion of my crop
while it was standing; nor were the latter less destructive,
when the poppy heads were spread upon the floor of the
summer-house in order to dry them. I was however indem-
nified for. this loss, by observing that not a single instance of
mortality presented itself to evince the noxious quality of
the seed.

If future experiments should prove, that both objects may
be pursued by the same culture, scarcely any plan can be
devised, which would prove equally profitable to the cultiva-
tor, and more beneficial to the community.
General itflec- I am n0* so sanguine, gentlemen, as to expect that any por-
tions. son Upon reading the above account will immediately resolve
to cultivate the poppy to a great extent, as an article of profit,
There is often a long repose between the acquisition of know-
ledge, and the application of it to practical purposes; and
in this case I allow that many difficulties are to be sur-
mounted, before the open and avowed consumption of this
oil would be sufficiently extensive, to make the production of
it an object of sufficient magnitude. But the increasing de-
mand for oils of all sorts in our extensive manufactories,
and by the daily improvements in our provincial towns, the
immense sums expended in the importation of foreign oils,
and most probably of this very oil under a false name, and
the daily increase of their price, render a power in reserve
most desirable. The time may arrive when the scarcity of
oils for domestic use may increase to an alarming degree ; in
this case the general reluctance to the use of those which are
now deemed of an inferior quality may in great measure
subside, and we may perhaps rejoice at being supplied at a
cheaper rate with that very oil, which passes smoothly among
us under the ficticious character of genuine oil of olives. I
shall at least enjoy the satisfaction of putting it in the power
of the public to assist themselves at some future period; and
take encouragement respecting the success of my endeavours
from the nature of this very plant, which is frequently
known to lie for years in the soil in a state perfectly inert,
until some favourable circumstances may have promoted a

vigorous

CULTURE OF THE POPPY FOR OIL. gC^

vigorous vegetation, to the surprise and alarm of the farmer,
who has uniform! v mistaken it for a weed.

N. B. It may be objected, that in the above estimate of
the profits, mention is not made of the duties which may
hereafter he imposed by government, and become consider-
able deductions. But this objection has uo reference to our
first essays. The duties will not become an object until the
product of popny oils shall s< nsibly diminish the importa-
tion of foreign oils; and in that case the wisdom of govern-
ment will doubtless prevent their rising so high, as to ope-
rate as a discouragement to a culture, which would turn the
balance of the oil trade in our favour; and should we be
able to extend this culture so fai as to export the article,
a very moderate duty upon both home consumption and
exportation may prove more than equivalent to the duties
at present collected.

Since writing the above, I am informed by a person
who deals largely in foreign oils, that letters from Leghorn
announce an alarming deficiency in the last year's product;
that the quantity is very small, and of a very inferior quality.
This information should operate as an additional motive to
the attempt recommended. The injury induced upon olive
trees by inclement weather is frequently to such an extent,
that it can only be repaired by the slow growth of new
plantations. This circumstance gives an astonishing ad- Advantage
vantage to a substitute, of which, by its being an annual frombeing***
product, the deficiency of the most unfavourable year
cannot be equally extensive, and would probably be sup-
plied by the increased abundance of the year ensuing.

IX.

2g8 tJSE 0? TOBACCO WATER.

IX.

On the Use of Tobacco Water, m preserving Fruit Crops, by
destroying Insects; and on the Use of the Striped or Rib-
band Grass* By Mr. Robert Hallett *.

SifLf Axminster, April 13, 1802,

EING much engaged in mercantile concerns, and hav-
ing but little time for other pursuits, I have not an oppor-
tunity, though extremely fond of my garden, of bestowing
the attention to it I could wish ; but having made a few ex-
periments with a view of improving the state and bearing of
my fruit trees, in which I hare succeeded beyond my high-
est expectations, I hope, as my intention is to benefit the
public, I shall be pardoned for troubling you with the pre-
sent communication of them.
Popular notion The old gardeners with us have long entertained an idea,
of wail-fruit tnat our climate has suffered a change particularly inimical
trees. to the successful cultivation of Wall Fruit Trees. To this

circumstance they attribute the blight, which annually dis-
appoints their hopes, and consider the evil beyond the reach
of their skill to remedy.
Common di«- The disease to which I have paid regard, is that which
ease of these a#ects tj,e trees m the early part of the season, curls up their
leaves, often destroys the young shoot, and not un frequently
reduces the tree to a state of weakness, from which it is sel-
dom to be recovered. I have, however, for some years past,
successfully combated this baneful complaint, 'with a pre-
paration easily to be obtained, attended with little expense,
and yet certain in its effect.
Tobacco de* The efficacy of tobacco in destroying insects has no doubt

1 been long known, and which I was well aware of. But as
the expense attending its use, either for fumigating my
trees, or washing them with an infusion, was considerable,
and was perhaps the obstacle to its being generally resorted
to, I endeavoured to find out the best method of obtaining

» Papers of the B-th and West of England Society, Vol. X, -p. 199.

"it

sect*.

USE OF TOBACCO WATER. 299

it in quantities at a cheap and easy Tate, of applying it with

the least possible waste, and of preparing it so as to be used

with safety. On considering the subject, it struck me that Water of t0-

i * ba -co & snuff

the tobacco water used by shepherds, having the power of manufacturers.

curing the scab in sheep, might answer my purpose ; and
having a tobacco and snurT manufacturer very near us, I ap-
plied to him, and had the pleasure of finding, that in pres-
sing his tobacco he obtained large quantities of it, which he
threw away as useless, except some little which he sold to
shepherds. This liquor was exceedingly strong; and, after
various trials, I found, that a quarter of a pint, or indeed
less if it was tolerably thick, would impregnate a gallon of
water with sufficient power to destroy every insect or reptile
that felt its influence ; and that two gallons of it, when di-
luted, were enough to wash all my trees, which are about
fifty, three times over, and to preserve them throughout the
season in the finest health and vigour.

My method of using it has been thus : as soon in the Method of
spring as I observe a leaf on any of my trees begin to curl, using
or be in the least diseased, I prepare my tobacco water as
I have before mentioned, viz. to something more than a
wine-glass full, or nearly to a quarter of a pint of the liquor,
I add a gallon of water ; and mix it well together. I then
sprinkle the whole of my trees over with this preparation,
with a brush such as the plasterers use in moistening their
walls, or sometimes by pouring it from a very small watering
^ pot with fine holes; beginning at the top of the tree, and
laying it on very gently to prevent waste, which would be
considerable, if done with violence or thrown from an en-
gine. Some time after, either in one, two, or three weeks,
as I find it necessary, I repeat the sprinkling ; and before
the fruit gets to a size to be stained by it, 1 go over them
again ; and have always found three times sufficient to secure
them from the depredations of the insect, which generally
preys on the leaves before the shoots are much advanced in
strength. I have now practised this antidote for some years ;
and having during that time taken every opportunity of com-
municating the knowledge of it, I have at this time the sa-
tisfaction of seeing it in such general use around me, that I
find our tobacco manufacturer has such a demand for the

liquor,

300 UTILITY OF tllBliAMD GRASS*

liquor, that he sells it at is. 6d. a gallon. It may, however*
no doubt, be obtained at a very cheap rate in Enstol, and
other places, where much tobacco is manufactured. 1 would
further add, that I have not confined my experiments of its
Destroys fn- use wholly to fruit trees. Every vegetable and shrub which

shmbs'and ve- * ^ave aPP^e(^ lt to nave ^een relieved by it, and restored to
getables. health, though ever so much injured by the insect tribe. I

have no doubt but it would effectually destroy the red spi-
der; and that it may be used with salutary advantage in
numerous other instances. And as it is a remedy so cheap,
and attainable in any quantity that may be desired, I hope
it will prove, on being generally known, beneficial to the
Perhaps appli- public. How far it may be practicable to use it in hop-
cable in hop grounds, or in other extensive views, I canuot say. But I
grounds. & . ' . ' J

should imagine, as one watering only has a most powerful

efficacy ; and as the labour of one man would in a day go
far in the application of it, that considerable benefit may be
derived from it wherever the insert preys.

I cannot dismiss my pen without mentioning a few words
respecting another experiment, which my situation prevents
my following up to the extent 1 could wish. I shall there-
Ribband grass fore briefly state, that observing from time to time the im-
very pro i c. ni€»nse produce of an ornamental grass, which I had much
of in my garden, and which is distinguished in Miller's
Dictionary by the name of Striped or Ribband Grass; it
occurred to me, that Nature in her bounty did not bestow
such a prolific quality on this beautiful grass, but for some
wiser purpose than merely to gratify the eye. I therefore
Excellent food examined it attentively, and found it to be very succulent,
for cattle. anj possessing much sweetness; and on offering it to. my
horses and cows, that they fed on it very eagerly. I had by
me a calf just weaned, which I kept wholly by it for a
month ; and notwithstanding it had so recently been taken
from its mother, this grass supported it admirably, and-I had
the pleasure of seeing it thrive beyond my most sanguine
Produce great, expectations. I ascertained in the course of the year, that I
could cut it three or four times, and that its produce was al-
ways prodigious. It takes a very deep root, produces an
early spring crop, and, I believe, is an excellent summer
food for cattle : in the winter it disappears. I should ima-
gine

USE OF TOBACCO WATER. 301

sine it may be raised from seed ; but I have found it to be Method of
easily propagated by dividing the roots into smaller plants,
and disposing of them at distances of from fonr to six
inches. In moist ground it spreads rapidly, and soon forms
a thick mass of food exceeding any other kind I ever wit-
nessed. Its durability is such, that what I have in my gar* Very durablt.
den, which has been there to my knowledge these twenty
years, is as thriving, and yields as much as ever.

I had need apologize for trespassing so long on your pa-
tience; and shall be happy if these remarks be in any degree
found beneficial.

I am, with great respect, Sir,

Your most obedient servaut,

ROBERT HALLETT.

[QCf It is presumed the destroying of insects, by sprinkling with to- Perhaps some

bacco water, is not new, though not generally practised ; it may there- indigenous

fore be a public service to recommend the method. But as tobacco is PI*nt.may De

n . , . , substituted for

comparatively a dear article, and the fluid above mentioned not easily tobacco.

procured in many situations, it might be a public advantage of no small

importance, if our ingenious correspondents would turn their attention

to the different tribes of vegetables, with a view to finding among our

most pungent and bitter plants, or by a cheap and easy mixture of them,

a substitute for foreign tobacco, for such uses. The idea is not without

promise. .

And further experiments on the striped grass are undoubtedly worthy

of being made, in small enclosures near the farmer'* or gentleman'/?

house. — Editor.]

X.

A Second Letter from Mr. Robert Hallett, on the Effu>
cacy of Tobacco Water in destroying Insects infesting Fruit
Trees,

SIR, Axminster, Jan. 14, 1304.

.S you requested in your favour of the 28th ult., that I
would communicate to you any farther discoveries that might
have occurred to me in the use of the tobacco water for de^

stroyinjj

30£ USE OF lOfiACCO "WATER.

stroying insects on fruit tree?, T trouble you with the result
of my experiments last year, as it will strongly tend to con-
firm my representation to you on the subject, in the spring of
1802.

Experiments Being from home in the early part of last season, when

with tobacco ° . '. r

water on fruit W trees were putting: forth their shoots, I was prevented

trees. the opportunity of applying the tobacco water as usual, and

found on my return several large peacTi and nectarine trees,
against a west wall in my garden, so wholly diseased, that
not a leaf was to be found on them, but which was curled
pp and full of insects. The trees were then well covered
with fruit of nearly the size of a hazel nut ; but being des-
titute of leaves to shelter them, I despaired of saving any,
and was apprehensive of losing even the trees. I imme-
diately prepared some tobacco water, of more strength than
usual, and applied it by sprinkling it very forcibly from a
brush, and in two or three days I could perceive the insects
were nearly all killed. I then renewed the application ;
and in about a week after I had the diseased leaves picked
off, and repeated the wash, and found it to be thoroughly
effectual. The trees completely recovered, put forth the
finest shoots possible, and ripened an immense quantity of
fruit in the highest perfection.
Ten years ex- I have now used it about ten years, and am more than
Sscac06 °f lU ever satisned> tnat ""thing can more effectually destroy
every insect, that ravages on the leaves of trees and plants
of all descriptions. And I conceive its benefits may be in-
valuable, if applied, as 1 observed in my former paper, to
exterminate in hop plantations those insects, which are so
destructive to the plants.

it being, as I have mentioned above, about ten years
since I resorted to the tobacco water, and recommended it,
its use has been gradually extending through this part of the
Has been mix- country ; and I observe, that some have mixed it with other
th W»th °Uier tmnSs» anc* having found benefit from it, have considered
their composition as an important discovery : but I am cer-
tain it has been several years longer in use by myself and
my particular friends near me, than by any other person ;
and that it requires not any additional ingredient to render
its good effects obvious, whenever properly applied. But I

find,

USE OF TOBACCO WATER. 303

find, that as the demand increases, the tobacconists weaken It ought to b©

what they send out ; and care must therefore be taken, that ^j^1" y

it be sufficiently strong when used, which may be known by

its giving the water a tolerably brown colour. I have found

sometimes a wine-glass full sufficient for a gallon of water ;

at other times, what I have procured has been so much di»

luted by the tobacconist, that it has required a pint to give

a proper strength to that quantity. I was last summer

greatly annoyed by the red spider on those trees that had a Red spidtr.

direct south aspect. The minuteness of the insect, and

being so securely sheltered underneath the leaf, prevented

several of ray applications from taking a due effect; but on

watering my trees with an engine for about ten successive

evenings, very forcibly, and immediately after being so wa«-

tered giving them whilst wet a sprinkling of tobacco water,

about three of those evenings, the trees recovered and ripened

their fruit very finely,

I hope next summer to have it in my power to inform you Apple trees
of the result of an experiment T am now making, with respect transPlante(*'
to transplanting apple trees from an orchard near me, that
is about to be converted to some other purpose, Havin«-
purchased as many of the trees as I was desirous of remov-
ing, 1 have newly planted out about forty of them, several
of which bare each a hogshead of eider last year, and hare
done it in many previous seasons. As I have paid great at>
tention to the preservation of them, I have little doubt of
success. But as it cannot yet be ascertained, I shall defer
enlarging upon the subject till I have the pleasure of ad- •
dressing you again, tn the mean time I remain with great
respect,

Your most obedient servant,

HOBERT HALLETT,

XI,

304 REMARKS OK MR. VfNCE's PAMPHLET.

XT.

Remarks on a Pamphlet, lately published by the Reverend
S. Vincr, respecting the Cause of Gravitation. By a Cor-
respondent.

To Mr. NICHOLSON.
SIR,

Mr. Vince's JlT is not long since I first saw Mr. Viuce's pamphlet re-
thecausc of sPectm& Sir Isaac Newton's conjectures on the cause of
gravitation. gravitation ; some parts of it appear to me so erroneous and
so injudicious, that I think it right to take the first oppor-
tunity of expressing the disapprobation, which the author
seems to deserve.

Cannot be the After having shown, that the established laws of srravitu-
pressure of a ° . jf

medium vary- tion cannot be derived from the pressure of a medium, of

ing in density which the density varies simply as any given power of the

of the distance! distance, Mr. Vince proceeds in these words , (P. 21), " It

may be supposed, that if the above assumed law of density

of the fluid will not answer the required conditions, yet some

other law of density, which is compounded of different

powers of the distance, may be made to agree with the law

of gravity. Let us therefore represent the density of the

medium by P am + Q a1 4- R a* + &c« — Hence, according

to the foregoing reasoning (taking only the two first terms

of the series), the law of force tending to the sun is

p x 2 '"-'"" x a fei? - 1 + Q X a VttZ x a'2-£=^-

3e 2 He 2

1 -\- R, &c. Now these, being different powers of the dis-
tance a, the whole can never constitute a power which varies

Mis mistake as —77." On this point the Professor's whole demonstration

pointed out. aZ

rests, and it is difficult to imagine how he could have com-
mitted so palpable a blunder. We have only to put m — 0,
and R ~ o, in order to show the fallacy of his reasoning :
the force will then be respresented according to the expres-
sion here laid down, by Q X !£Z£J X ?±ZlI!_lf' and

a e '<5

"? qn — j 11]av become ~ — 2 on many suppositions, while

the

REMARKS ON MR. VINCE's PAMPHLET. 305

But

nce*s Another er-

the density is expressed by two terms of the first series,
in fact there appears to be another mistake in Mr. Vi
calculations, for instead of 2 wi and 2 q, he ought to have1"
written 3 m and 3 q ; Mr. Vince says, *' let the density be as

rT1, then — the distance of the particles is as ^ " (p. 17) :
Newton on the contrary, says, " particularum distantiae Newton's av
erunt ut cuborum latera A B, a b, et mediorum densitates
reciproce ut spatia continentia A B cub. et ab cub." II. 23.
So that if the density be expressed by P — ~, n being — 1,

which is the power of the distance of the particles of an
elastic medium expressing their repulsive force, the law of

2 Q
the derivative force will be represented by - — -

Sea2,

These errours in the work of a Professor of Astronomy
and Experimental Philosophy, and a Professor in the Uni-
versity of Cambridge, afford no very flattering specimens of
the mathematical attainments of this country: and 1 am
sorry to say, that they have been passed unnoticed by one of Mistake unno-^
the most respectable of our reviews, in which a copious ac- R^'iew.
count of the essay is inserted. " If the salt has lost its sa-
vour, wherewith shall it be salted ?" Et quis custodiat ipsos
Custodes ?

Mr. Vince has thought proper to complain, in his prefa- Complaint of
tory statement, of the conduct of the Council of the Royal ^ainst^he
Society, and in particular of that of its President, in de- Royal Society,
clining to publish his essay in the Philosophical Transac-
tions. He says, that it was presented by the Astronomer
Royal to the Society, " when the President and one of the
Secretaries requested, that the author would withdraw it,
and present it again in the November following, as the pa-
per appeared a proper subject for the Bakerian Lecture. It
was accordingly withdrawn, and offered again at the time
when it was requested to be presented. The paper was then
read, and appointed to be the Bakerian Lecture. But before
it went into the Committee which is expressly appointed to
examine and determine what papers shall be printed, the
author was informed, that it was doubtful whether his paper
would be published. The circumstances attending this in-
Vol. XIX— April, 1808. X formation

206

REMARKS ON MR. VINCE S PAMPHLET.

The Society
vindicated.

Farther re-
marks.

formation led him to suspect, that it would not appear in
the Transactions of the Society, and in this he was not dis-
appointed.'*

In the whole of this important history thfre appears to me
nothing whatever, that an impartial person could deem a
just cause of offence. The author had more than once be-
fore been appointed to give a Bakerian Lecture; and when
he offered this paper to the Society, " the President and one
of the Secretaries" probably thought it a compliment due
to his established reputation, to suggest to him, that it might
serve for a Bakerian Lecture, without having gone farther
than the title of his paper. He accordingly accepted the
compliment and -.the fee. The paper having been partially
read, as all mathematical papers must be, it is natural to
suppose, that it was submitted to the examination of some
one or more individuals, previously to its being discussed by
the Committee of papers, since mathematical demonstra-
tions cannot easily be examined by any large body of per-
sons, however select; and as the opinion of such individuals
might easily be expected to influence the determination of
the Committee, it is not difficult to imagine, that it might
be known beforehand, " that it was doubtful whether the
paper would be published," although it may be questioned,
whether or no the person who gave the hint aeted with per-
fect discretion.

After these remarks on the mathematical parts of Mr.
Vince's paper, and this attempt to explain the conduct of
the Council of the Royal Society, it will scarcely, be neces-
sary to make any comment on the unjust and illiberal insi-
nuation conveyed by the observation, that '* Sir J. Pringle,
the late worthy and learned President of the Royal Society,
executed the duties of his high office with great impartiality
and honour" Nor shall I enlarge at present on any other
objections which might be made to Mr. Vince*s essay : what
be says respecting the interference of the ethereal atmo-
spheres of the different planets is totally foreign to the ques-
tion ; and some others of his remark?, which are perhaps
better founded, have already been stated by Professor Ro-
bison, and by other authors : but these are imperfections

which

ON THE BASI OF FOTASH. 307

which might easily be forgiven, if they were the only errours
that have been committed in the essay.

I am, SIR,
Your obedient humble servant,
3 March, 1808. DYTISCUS.

See errata at the foot of the last page.

XII.

Farther Experiments and Observations on Potash and its Base.
In a Letter from Mr. C. Sylvester,

To Mr. NICHOLSON,
Dear Sir, Derby, March 28th, 1808.

J N your Journal for February of this year, I communica- Detonating
ted an account of some experiments, made, in company with ducec? frorn^
my friend Mr. James Oakes, with a view to produce the me- potash,
tallic base of the alkalis, discovered by Professor Davy. In
consequence of our not having sufficient galvanic power at
that time, we did not succeed in separating the globules of
metal from the potash, although we produced a substance,
which detonated with a bright flash, when presented to wa-
ter. We have however since repeated the experiments, with Completely se.
increased power, and have completely succeeded in producing para e rom
the metal, detached from the alkali, in which it is imbedded.
The result of these additional experiments I should, accord-
ing to promise, have communicated for insertion in the suc-
ceeding number of your Journal; but, observing, both in
your, and other periodical works, that the same result had
been obtained by others, I conceived any farther detail un-
necessary: as however wc have paid attention to the pro-
duction of the black matter alluded to in my last, which ap- Black matter
pearance has not been observed by any other experimen- accomPan> in8
talist, I have thought proper to make a few additional re-
marks.

After repeating the experiments several times, we ascer- Formed at the
tained tho curious fact, that the black matter was lormed at JJJP r
X 2 the

30$ ON THE BASB OF POTASH.

the wire coming from the copper end of the apparatus only.
tob^aSon" Suspecting from its blackness, that it might be carbon, we
collected and dried a portion of it, which was subjected to
the test of nitre in a platina. spoon; we did not, however,
observe the slightest indication of the presence of that in-
flamable body; but, since the quantity operated upon was
very small, no absolute conclusion can be drawn from the
experiment.
Cannot be an That it cannot be an oxide of the alcaline base containing
base.e° 6 *ess ox'Sen tnan constitutes alkalinity, appears from its re-
maining permanent jn water, for several weeks after the ex-
periment ; a circumstance, which could not take place with
any substance having so great an affinity for oxigen : It is
equally evident, that it cannot be an oxide with more oxi-
gen, because it is formed at the copper end of the battery.
Is it any foreign matter, derived from the vegetable, whence
the potash has been obtained ?
Alkaii formed It is a well ascertained fact, I believe, that vegetables fur-
of vec "tables" msn a greater quantity of alkali by incineration, than is to
but in what be found in their composition previous to the process. It

state does it would therefore seem, that alkali is formed during the com-
exi»t in them r ' 7 .

bustion, and that all of it does not exist in the vegetable in

the state of alkali : nor does it exist in the state of its base,
since this substance would be incompatible with the pre-
sence of the vegetable fluids, in what form, then, does it
exist?
Alkalis com- In consequence of the numerous confirmations of Mr.
^a^th-5' h E>avv>s discovery, we may with some confidence conclude,
the same. that the alkalis ought no longer to be considered as simple
bodies, and it is exceedingly probable, that the earths are
also compounds of oxigen, united to certain inflammable
bases; a circumstance long ago suspected by Lavoisier,

Chemical no- an(j otners# i^e nomenclature and systematic arrangement
menclature and .

system require of chemistry therefore must undergo an alteration, particu-
ac ange. larly that part of the former, which embraces oxigen and its

compounds; since we find that substance to be as well the
principle of alkalinity, as of acidity. Under the new ar-
New arrange- rangement all ponderable matter will most likely be divided
ment. jnt0 tw0 ciasscs> 0f simple bo, lies, namely, oxigen and in-

flammable

MEASURE OP A DEGREE ON THE COROMANDEL COAST. QQg

flammable bodies; from which will result the following
classes of compounds, first, all those formed by the union of
inflammable bases, and secondly, the simple and compound
oxides. The simple oxides will include all oxides, properly
so called, the acids, the alkalis, and the earths; under the
compound oxides will be comprised the various genera of
neutral salts*

1 am, Sir,
Your most obedient humble Servant,

CHARLES SYLVESTER.

A spontaneous explosion of the alkaline base, mentioned
by your Correspondent, page 146 of the present volume, oc-
curred to us; the effect of which fractured the glass tube in
which the experiment was made.

Erratum. Vol. XIX, page 157, line 7, fir " cock/' read,
" cork/'

XIII.

An Account of the Measurement of an Arc on the Meridian
on the Coast of Coromandel, and the Length of a Degree
deduced therefrom in the Latitude 12° 32'. By Brigade
Major William Lambton *.

I

N a former paper which I had the honour to communicate pian for mea-
to the Asiatic Society, I gave a short sketch of an intended suring an arc
plan for establishing a series of connecting points com-
mencing from the Coromandel Coast, and extending across
the Peninsula ; but that paper was only meant to convey a
general idea of the principles on which the work was to be
conducted ; a more circumstantial and scientific account, it
was thought, would be more to the purpose, when I had the
means of putting the plan in execution, and detailing the
particulars. Since that time I have received a most com-
plete apparatus, which has enabled me to proceed on the

* Abridged from the Asiatic Researches, vol. VIII.

•cale

310 MEASURE OF A DEGREE ON THE COROMANDEL COASTV

scale I originally proposed, and what is here offered is the
beginning of that work, being the measurement of an arc
on the meridian, from which is deduced the length of a de-
gree for the latitude 12° 32', which is nearly the middle of
the arc

An account of the base Tine.

The place of Some time had been taken up in examining the country
best suited for this measurement, and at length a tract was
found near St. Thomas's Mount, extremely well adapted for
the purpose, being an entire flat, without any impediment
for near eight miles, commencing at the race ground, and
extending southerly. This being determined on, and the
necessary preparations made, it was begun on the 10th of
April, and completed on the 22d of May, 1902.

Instruments I had expected a small transit instrument from England,
' for the purpose of fixing objects in the alignement, and for

taking elevations and depressions at th£ same time ; but that
instrument not having arrived, I thought it unnecessary to
wait, particularly as the ground was so free from ascents and
descents ; I therefore used the same apparatus as I had for-
merly done, viz. the transit circular instrument, and the le-
velling telescope fixed on a tripod with an elevating screw
in the centre. In all horizontal directions, this telescope
fully answers the purpose, and as there has been no deviation
from the level to exceed 26' 30' , excepting in one single
chain, and those cases but very few, I feel entirely satisfied
as to the accuracy of the whole measurement.

The chain. The chain which was made use of is the one 1 formerly

bad ; and I was fortunate enough to receive another from-
England, made also by the late Mr. Ramsden, and this
having been measured off by the standard in London, when
the temperature was 50° by Fahrenheit's thermometer, it
afforded me an advantage of correcting for the effects of
expansion, a circumstance in which I was by no means sa-
tisfied in the former measurement. In order, therefore, to
have a standard at all times to refer to, I hiive reserved the
new chain for this purpose, and used the old one only as a
measuring chain, by which means I can always determine the
correction for the wear.

There

MEASURE OF A DEGREE ON THE COROMANDEL COAST. 3 J J

There were only four angles of depression, and two of Proceeding on

elevation, taken in the whole length of the base; the rest rajsing°r lo^-

, enng the cof-

were all horizontal measurements, and many of them consist fere.

of a great number of feet before it became necessary either
to sink or elevate the coffers ; when that was done, great
care was taken to mark the termination of the preceding
measurement ; and for that purpose a small tripod was used
in the shape of a T, with three iron feet to run into the
ground, the straight side of which T was placed in the line.
Another small t was made with its top also parallel to the
line, and fixed upon the large one so as to slide to the right
or left, and upon that again was a long piece of brass made
to slide out at right-angles to the top of the T ; in the mid-
dle of this brass a mark was made, which was brought to a
plumb line let fall from the arrow, and the height from the
brass to the arrow was noted down ; when the succeeding
chain was laid, which was to commence the new level or
hypothenuse, the arrow was then brought so, that a plumb
line, freely suspended, would coincide with the mark on the
brass slider. The height of that chain above the brass was
likewise taken ; by comparing these two heights the eleva-
tion or depression of the new commencement was deter-
mined; and these differences noted in the seventh and
eighth columns of the table. The differences of the two
aggregates contained in these columns, when applied to the
ascents and descents, will therefore show how much one ex-
tremity of the base is above the other. The height of the
chain at the commencement and termination of the whole
was of course taken from the ground.

All the other particulars respecting this measurement are
nearly the same as that in the Mysore country, a full ac-
count of which has been published in a former volume of
the Asiatic Researches. Some little alterations have been Coffers,
made in the coffers ; that is, they were all of the same length,
and the whole together about ninety-six feet, so as to give
room for the pickets with the brass register heads. Their
sides continued to the ends, and their depth on each side
was the same, for the purpose of being turned every day,
that they might not fall iuto a curve by their own weight and
that of the chain. I also used tripods with elevating screws

in

312 MEASURE OF A DEGREE ON THE COROMANDEL COAST.

in the centre, for supporting the coffers, making no other
use of pickets than for the drawing and weight posts, and
for carrying the register heads. The top of each stand or
tripod was a thick circular piece of wood, fixed firmly to the
end of the elevating screw, and a slip of board was fastened
across the circular top, screwed into the centre, and allowed
to turn round. When the ends of two coffers were placed
on the top piece, this slip of board was admitted into the
under part of each, and prevented their sliding off, a
precaution that was very necessary on account of the high
winds.

Commence- The point of commencement of the base was had by drop-

ment of the ping a plummet from the arrow of the chain suspended by
a silken thread. A long but small bamboo picket had been
driven into the ground, till its top was level with the sur-
face, and the cavity of the bamboo was such as just to re-
ceive the plummet, and when the first chain was in the cof-
fers, drawn out; by the weight at the opposite end, it was
adjusted by the finger screw at the drawing post in such a
manner, that the plummet might hang suspended over the
cavity of the bamboo, while the thread was applied to the
arrow. This was done within the observatory tent, that the
plumb line might hang freely without being disturbed by
the wind. The bamboo picket was preserved with great care
during the time I was observing for 'the latitude, and was
then protected under the frame of the zenith sector. When
the tent was removed, a large bamboo flag-staff was erected,
the cavity of which covered the picket, and in this state it re-
mained until the measurement was completed.

Termination of At the termination of the base, being the end of a chain,
one of the large hooped pickets was driven into the ground
till its top was on a level with the cofFers and under the ar-
row of the chain. The opposite end being adjusted by the
finger screw, the arrow at the leading end was nearly the
centre of the picket. A mark was made, and a small round
headed nail was driven in till it was level with the surface.
The chain was again applied, and the arrow cut the centre
of the nail. I he picket had been driven upwards of two feet
and a half into very hard clay.

The extremi- But that these extremities may be preserved, in case they

i *»>'

MEASURE OF A DEGREE ON THE COROMANDEL COAST. 313

may hereafter be referred to, I efeteted small masses of hewn ties marked.

stone eight feet square at the bottom and four at the top,

the axis of these masses being made to pass through the

points of commencement and termination, and in order that

this might be correctly done, the following method was

used.

I marked out the foundation of the building, so that the Structure of
... , . , » iT -ii the truncated

picket might be as nearly in the centre ot it as possible. pyrami<Jatthe

The earth was dug about a foot deep, reserving a space end,
round the centre untouched. After the foundation was
brought to a level with the surface, the first tier of stones
was laid, being one foot in height. The inner part was then
filled up with stones and mortar, taking particular care at
the same time, that the centre was not touched. The next
tier of stones was then laid, which was six feet square and
one foot high. This also was filled in with great care, and
some cement and bricks put gradually round the picket.
After that the last tier was laid, which was four feet square,
and also one foot high. When these stones were firmly
fixed, small silken threads were drawn across each other in
the diagonals of the square. A plummet (pointed) was
then suspended from the point of intersection of these
threads, and they were so moved, that the point of the
plummet coincided with the centre of the nail in the picket.
The position of these threads being determined, marks were
inserted in the stone. The cavity was then filled up, and a
square thick stone was fixed in the middle of the mass, hav-
ing a circular place of about four inches diameter, sunk half
an inch deep, and the centre of which was marked by a point.
This point, by moving the stone and again applying the
silken threads, was brought to coincide with the point of in-
tersection, and then it was firmly fixed and pointed.

Precisely the same kind of building was erected at the and of that at
beginning of the base, but, in place of having a picket in ^J56^™"'
the centre, four large hooped ones were driven into the
ground, forming a square of about ten feet, the small bam-
boo picket being intended as the centre. Silken threads
were then drawn across from the diagonal pickets, and so
moved, that the plummet first u*ed, suspended from the
point of intersection of the threads, might drop into the ca-
vity

gJ4r MEASURE OP A DEGREE ON THE COROMANDEL COAST,

vity of the bamboo. That being adjusted, lines were drawn
on the tops of the pickets where the threads had been ex-
tended. The building was then erected, and the centre
both of the second and Inst tier was marked by the inter-
section of those threads, when applied to the marks on the
pickets.

Such has been the mode of defining the extremities of the
line. The buildings are well built of stone and some brick,
and will remain for years, if not injured by acts of violence.
They are intended to receive an instrument on the top, and
the points are points of reference, if it should ever be jthought
necessary to have recourse to them.

Expansion of the chains, and their comparative lengths.

Comparison of ^s ' wished to be satisfied with respect to the expansion
the chain used of each of the chains, and their comparative lengths, I made
^indarcT* a course °^ experiments for both purposes. I had accord-
ingly the coffers arranged near the ground, that the drawing
and weight posts might be driven deep and firmly fixed.
Both the chains were then put into the coffers, and the com-
parisons made as follows :

April 10, at 6 P. M. the temperature by a mean of five
thermometers was 850,6.

Three comparisons were made, and the old chain ex-
ceeded the new one, nine divisions of the micrometer screw.

April 10, at 6 A. M. the temperature by a mean of five
thermometers was 79°-

Four comparisons were made, and the old chain exceeded
the new one nine divisions. Therefore at the commence-
ment, the old chain exceeded the new one in length, nine
divisions of the micrometer.

May 23. After the base was completed, the temperature
by a mean of five thermometers, was 86°.
By a mean of five comparisons,
the old chain exceeded the

new one 10*65 divisions.

24. The temperature by a mean of five
thermometers was 84°.

And

MEASURE OE A DEGREE ON THE COROMANDEL COAST. 515

And a mean of six comparisons
gave the excess of the old
chain above the new one* • • • 1T08 ditto.
25. The temperature was 87°.

And a mean of two compari-
sons, crave. 1 1*00 ditto.

Mean 1086 ditto.

Hence it appears, that, at the conclusion of the base, the
old chain was longer than the new one 1 1 divisions of the
micrometer very nearly, so that it had increased, from being
in use, 2 divisions, or T£T of an inch.

These experiments were made with great attention, and
when either chain was stretched out by the weight, it was
carefully brought into a line in the coffers.

As I had reserved the new chain for a standard, and know- Rateof expan-
ing the temperature at which it had been measured off in
London, I considered it an object to determine its rate of
expansion and contraction compared with the thermometers
which had been in use in measuring the base, since these
were but common ones, and might probably differ from those
made usa of by General Roy and others, who had deter-
mined the expansion of metals by the pyrometer; and I was
farther induced to do this, from seeing the great variation
among them, when the degree of heat became above one
hundred, which it generally was in the coffers every day be-
fore I left off. To avoid those irregularities arising from the Time allowed
expansions being checked by the resistance from the pres- J? Jj ™ftQ,
sure on the coffers, I chose the times of sunrise, and from tion.
one to two o'clock, P. M. for making the observations.
Sunrise in India is generally the coolest time of the twenty-
four hours, and the chain had during the night, on account
of the uniform state of temperature, full time to free itself
from any resistance. At the hottest part of the day likewise
there is a considerable time when the thermometers are
nearly stationary, which will afford time for the resistance in
the coffers to be overcome ; and it is necessary to pay parti-
cular attention to this circumstance, for the chain will be
perceived to lengthen often for nearly half an hour after the
thermometers are at their highest.

I had

31$ MEASURE OF A DEGREE ON THE COROMANOEt COAST.

I had made a great many experiments prior to .the mea*
Suretnent, but found great irregularity, partly from not at-
tending sufficiently to the above circumstance, and partly
from the unsteadiness of the drawing post, notwithstanding
it was driven deep into very hard ground, and secured, as I
thought, by having large stones pressed close on each side
of it. To remedy this latter inconvenience, I had a staple
driven into a brick wall, into which the iron was fixed with
the adjusting screw for the chain, after which I perceived a
perfect coincidence with the arrow and mark on the brass
head, except what arose from the trifling expansion and con-
traction of the iron which held the chain. I then began a
Bew course of experiments on both the chains, and the re-
sults were as follows.

Experiments for determining the expansion of the new
Chain.

Expansion of
the standard
chain.

1802.

si

4} t*

> ■

Total ex-

Total

TIME.

I 1

8 • »;

3 £t)

■v c
• .2

pansion
and con-

due to
1°.

Remarks*

Month.

4! -a S

uh 2

3 'x

2;

traction.

June 4.

2 P.M.

11 6*4

Inches

Inches

5.

O rise.
2 P.M.

83

123*8

33-4
40*8

51

64

•245157
•307648

•00734
•00754

Weather
clear and

6.

0 rise.

82 5

41*3

64

•307648

•00744

windy

14.

0 rise.
2 P. M.
0 rise.
2P.M.

80
H9'l

81*4
121-9

79*7

39*1

60

•288420

•00737

during
the whole

15.

37*7

5/

•273999

•OO727

of these

40 5

63

•302841

•00747 experi-

16.

0 rise.

42-2

66

•317262

•00752

ments.

Mean -00752

Experiments

SCIENTIFIC NEWS.

317

Experiments for determining the expansion of the old
Chain.

1802.
Month.

TIME.

Mean of 5
Thermome-
eis

Change or
Tempera-
ture.

> •
. S
z

Total ex-
pansion
and con-
traction.

Total

due to
1°.

1
Remarks. (

June 8.

9.

12.

13.

14.

0 rise.
2 P.M.
0 rise.
1P.M.
0 rise.
2 P. M.
0 rise.
2 P.M.
O rise.

83-5
110-3

85-2
110

80-2
108-1

83-3
1113

80

26-8
25*1

24'8

27-9
24*8
28
31*3

42
40
39

42
38
42
46

•201894
•192280
•187473

•201894
•182666
•201894
•221122

•00749
00766
•00755

•00724
•00736
•007"21
•00706

Cloudy
weather
and high
winds du-
ring the
whole of
these ex-
periments.

Mean

•00737

Expansion of
the measuring
chain.

It appears from these results, that the expansion due to
1° of the thermometer is less than what has been allowed by th^nTnowed
experiments made in England; but this might arise from in England.
the thermometers, as they were such as could be purchased
in the shops, and therefore most probably not of the best
kind. Great care, however, was taken to watch the moment
when they stood the highest, and though they varied from
one another considerably at that time, yet that variation was
generally the same in equal temperatures.

(To be concluded in our next, J

SCIENTIFIC NEWS.

Wernerian Natural History Society,

J\. Society has been established at Edinburgh for the cul- Wernerian

tivation of the different branches of natural history. It has Natural Hlsto.

J ry Society at

been denominated the Wernerian Natural History Society, in Edinburgh.

honour of Werner. The following gentlemen have been

elected office bearers.

PRESIDENT,

318

SCIENTIFIC NEWS.

PRESIDENT,

Robert Jameson, Esq. F.R.S. Prof. Nat. Hist. Edin.

VICE PRESIDENTS,

Wra. Wright, M. D- F.R.S.
Rev. T. Macnight, F. R. S.

John Barclay, M. D. F.R.S.
Tho.Thompson, /!/.£>. F.R.S.

Patrick Walker, Esq, Treasurer.
Pat. Neil. Esq. Secretary.
Council, — nine in number, viz. The above office bearers,
with Charles Anderson, Esq. F. R. C. $.: and Lieut. Col. Ful-
Jerton, of Bartonholm. Sir Joseph Banks, President of the
Royal Society of London; Richard Kir wan, Esq. President of
the Royal "Irish Academy ; and Professor Werner of Frey-
berg, were elected honorary members. The following
foreign members have been elected. Professor Karsten, Ber-
lin; Professor Klaproth, Berlin; Mr. Von Humboldt, Berlin;
Mr. Von Buch, Berlin; Mr. F. Mohs, of Stiria; Mr.
Herder, Mr. Friesleben, and Mr. Meuder, of Saxony.

True reins
characterized.

Two orders of -At the last meeting of the Wernerian Natural History So-
veins of miner- ciety, Professor Jameson read a description of contempora-
neous or enclosed veins. He divided veins into two classes.
The first class comprehends true veins, the second contempora-
neous or enclosed veins.

True veins, he remarked, excepting when the strata or
beds are of uncommon thickness, traverse many different
strata or beds; and, although we do not always observe them
open at the surface of the earth, they invariably open at the
surface of the formation or series of formations they traverse ;
thus the outgoings or openings of certain metalliferous
veins, that traverse clay, slate, and mica slate, are sometimes
covered by the second porphyry formation.

Contemporaneous or enclosed veins are in general con-
fined to individual beds or strata, and are completely enclosed
in them, or in other words wedge out in every direction in
the bed or stratum in which they are contained. After de-
tailing the various characters of true and contemporaneous
veins, the Professor next described the contemporaneous

veins

Contempora.
fieous or en-
closed veins.

SCIENTIFIC NEWS. . 31J

veins that occur indifferent great rock-formations, beginning
with granite, and ending with the newest ftcetz trap forma-
tion. He next explained the mode of formation of these
veins. When describing the contemporaneous veins, that
occur in gneiss, he remarked, that certain varieties of veni-
genous gneiss bear a striking resemblance to granite, and
hence have been frequently confounded with it. This led
him to point out the characters by which true granite veins
are distinguished from veins of granitic gneiss.

As connected with this part of the subject he examined the Ramark on the
facts, on which the Huttonian theory of granite is founded ; th"0tryniaft
and proved by a detail of his examination of the appearances
described by Dr. Hutton, Professor Playfair, and others, that
the supposed granite veins, shooting from subjacent granite
into superincumbent rocks, are merely veins of granitic
gneiss accidentally in contact with granite.

Professor Jameson has just published the third volume of professorjame.
his System of Mineralogy, under the title Elements of Geog- son's Elements
nosy. The contents of this valuable work are as follows, or Scfvol" ofhi*
Chap. I, Description of the surface of the earth; chap, 2, System of
Effects of water on the surface of the earth ; chap. 3, Inter- inera Q^y'
nal structure of the earth ; chap. 4, General account of the
different formations in regard to their succession and strati-
fication, and this illustrated by a short description of the
Ilartz and Saxon Erzebirge; chap. 5. Theory of the dimi-
nution of the waters of the globe — Description of overlaying
formations — An investigation of the original contents of the
waters of the globe, during the different periods of the earth's
formation. The division of rocks into five classes; chap.
6, class 1, Primitive rocks ; chap. 7, class 2, Transition rocks,
chap. 8, class 3, Floetz rocks ; chap. 9, class 4, Alluvial
rocks; chap. 10, class 5, Volcanic rocks; chap. 11,
Mineral repositories; chap. 12, Relative age of metals,
and general inferences. These are followed by a table of
32 pages, containing the relative antiquity and geognostic re-
lations of simple minerals : also an extensive table of the

most

520 SCIENTIFIC NEWS.

most remarkable heights of mountains, hills, and lakes in
different parts of the world, and a table of volcanoes. The
volume is concluded with a series of notes explanatory of
passages in the text, and referring to the Huttonian theory
of the earth.

TO CORRESPONDENTS.

Jt would.be highly gratifying to the author of this Jour-
nal, to publish a complete Index of the whole to the present
time; and there is no motive for hesitation, but the probabi-
lity, that the heavy expense attending it might not be indem-
nified in the actual sale. It is, however, under considera-
tion.

The MeteorologicalJournal will appear in the first number
of the next volume ; and every attention that circumstances
can admit will be paid to the suggestions received in the favour
from an anonymous correspondent.

The errour of a word which he notices, is of the press, and
we trust that errours of this description are not very frequent
with us.

The tetter from Mr. Garnett, of New York, was received
too late for insertion this month, but will appear in our next
number. His favours will be always acceptable. The en-
closure to the Astronomer Royal was immediately forwarded.

ERRATA.

Page 304, 1. 10 from bottom, read

Oe

1. 7 from bot. for — read a2,

lioe 2 from bot. read Q X *S^H X a — I —

A

JOU

OF

NATURAL PHILOSOPHY, CHEMISTRY,

AND

THE ARTS.

"SUPPLEMENT TO VOL. XIX.

ARTICLE I*

Remarks on the tot id Eclipse of the Sun, June 16, 1806/
with some nezo Methods of finding the Sun or Moon's
Meridian Altitude, and the approximate Time, by AU
titudes taken near the Time of Noon. In a Letter from
J. Garnett, Esq. Editor of the American Nautical
Almanac,

To Mr. NICHOLSON.
SIR,

A AM a constant reader of your valuable Joiirnal, but Mistake of the
have only lately received your No. 75, in which, from the ^Sn^o*
proceedings of the French Institute, you have copied Mr. the French
Ferrer's observation of the total eclipse of the sun atIa$titute-
Kinderhook. As I assisted him in the observation, I beg
leave to remark a considerable errour, made by you or the
French Institute, which places Kinderhook upward of 7k
to the eastward of Paris, instead of Upward of 5h to the

westward.

h. nv. •
You mark the time of the conjunction 11 45 33*
whereas it was, apparent time - 23 25 33,2>
as you will perceive by the printed calculation enclosed.

Before

* I copied this time from the Magazin Encycloptdique, and on

referring to the Journal de Physique, where there is likewise a

Vol. XIX.— Supplement. Y brief

322 to£AL ECLIPSE Of THE SUN OF 1806.

limb of the Before the end of the total eclipse, the west limb of the
moon illumi- moon began to be illuminated, and the light increased so-
the end of the rapidly, that I at last mistook it for the sun's egress, and
eclipse. called the time to Mr. Ferrer: but he saw the errour, and

still kept his eye to the glass, when the first solar ray nearly
I * blinded him.

Whence this? Whence could proceed this illumination? from a lunar

or solar atmosphere ?
American Nau- In the American Nautical Almanac, which I hare pub-
lished here since 1803, I have given the moon's declination
for every six hours, instead of twelve ; which I did before
I knew it was done in France, and for the same reason.

tkal Almanac.

I am, with the greatest esteem,

Sir,

Your obedient Servant

JOHN GARNETT.

Vew York, North America.
February , 6, 1808.

Brief notice of it, I find the time set down 1 lh 25' 33". This is
evidently according to the popular, not astronomical notation of
time ; and in a work intended for the general reader, as well as the
astronomer, it was perhaps preferable. It appears however to have
occasioned the errour of the French reporter of the proceedings of
the National Institute,

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METHODS OF FINDING MERIDIAN ALTITUDE. 32&

N. B. The number of seconds in table XVIII may be Method of
found independent of the tabic, thus; add the constant ridian°altitude
log. 0.29303, the log. cosine of latitude by account, and and approxi-
log. cosine of declination together; and subtract the log, two altitude.°m
sine of the difference or sum of the latit. and declin. ac-
cording as they are of the same or different names ; the
remainder will be the logarithm of the number of seconds
in table XVIII.

If to this log. be added twice the log. of any number of
minutes less than 30 minutes, the sum will be the logarithm
of a number of seconds; which added to the altitude, taken
at that number of minutes from noon, will give the wie-
ridian altitude, the same as above.

REMARKS.
1. If the number of seconds that the sun or moon's de-
clination changes in one minute, be divided by twice the
number of seconds found from table XVIII, the quotient
in minutes will be the Correction of Noon, from equal
altitudes, for any less interval of time than twenty
minutes.

2. This correction is also tlie time, in minutes, between
the sun and moon's greatest altitude and meridian al-
titude.

3. And if this correction be multiplied into half the num. '
ber of seconds that the declination varies in one minute,
the product will be the difference, in seconds, between the
sun or moon's greatest and meridian altitude, which, re-
specting the moon, is sometimes considerable; therefore as
the altitude found by this problem H -f-A is strictly the
greatest, not the meridian altitude, and the time F and G
is the time before and after the greatest attitude: this pro-
duct should be applied as a correction to reduce the moon's
altitude when thus found, to her true meridian altitude,
when that is required.

See also Remark 2 on the page next but one.

fROBLEar

326

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328

ON PRETEXTING THE DECAY OF WOOD.

Tlighly impor-
tant to preserve
wood from de-
cay.

Two causes that
destroy it.

Two kinds of
rot:

wet,

and dry,

Dead matter
subject to de-
composition,

only under cer-
tain circum-
stance?,.
Fi-h and other
anitnal matter

II.

An Inquiry into the Causes of the Decay of Wood, and the
Means of preventing it. By C. H. Parry, M, D.*

JL HE power of wood in different forms to supply luxury,
to promote science, and to guard and prolong human life,
has made the means of preserving it from decay highly in-
teresting to mankind. With this view various premiums
have been offered by this and other ceconomical societies.
The object of the following discussion is to suggest the best
means of prevention, chiefly by inquiring into the nature
and sources of the evil against which it is intended to
guard.

Wood, when killed by being separated from its root, is
subject to gradual destruction from two causes, — rotting,
and the depredations of insects.

Of the rot there are two supposed kinds, as they affect
wood, first, in the open air, or secondly, under cover.

The first is that which in the terms of our premium,
Class VII, No. 3, is said to occur to u barn and other
outside doors, weather-boarding, gates, stiles, and imple,
ments of husbandry :" To which, if there were any need
of this minute specification, might have been added posts,
rails, paling, water-shoots, and various other objects.

The second is well known under the name of the dry.
rot, the cause and prevention of which are the subjects of a
premium by the Society of Arts in London.

Animal and vegetable substances possess certain common
properties and movements, which constitute what is called
life. When that state ceases, and these properties and mo-
tions no longer exist, the bodies become subject to the che,
mical and mechanical laws of all other matter.

When perfectly dry, and in certain degrees of tempera-
ture, both seem to be scarcely capable of spontaneous de-
cay. On this principle vast quantities of salmon are an-
nually conveyed in a frozen state to London from the north

* From Papers of the Bath and West of England Society,
vol. XI, p. 226.

Of

ON PREVENTING THE DECAY Of WOO». 329

of England and Scotland; and the inhabitants of the still preserved by
more northern regions constantly preserve their food, by ^iffpf^Li.
freezing, unchanged through the longest winters. The ge- sture.
latinous and other soluble parts of animal substances, when
extracted by boiling, and kept in a soft moist state, Terj
readily putrefy. But if the same matter be dried by a
gentle heat, and secluded from moisture and air by being
kept in bottles or metallic cases, it will remain very long
without decay. This is the theory of that well-known and
useful substance, portable soup. In the burning climate of
Africa, when it is intended to preserve a dead animal for
food, all that is necessary is to cut the muscular parts into
thin strips, from which, in a few hours, the heat of the sun
exhales all moisture, reducing them to a substance like
leather or horn, which proves to be unsusceptible of future
decay from putrefaction. So also entire human bodies, bu-
ried in the arid sands of those countries, have often been,
found converted by exhalation and absorption of their na-
tural moisture into a dry hard sort of mummy, incapable of
any farther change from the agency of those causes, to
which, in such situations, they are exposed.

Similar causes produce the same effects on wood. Even Timber long

under less riffid circumstances of this kind, as in the roofs Preserve? m

& ' large buildings,

and other timber of large buildings, it continues for an

astonishing length of time unchanged; witness the timber
of that noble edifice Westminster Hall, built by Richard II
in 1397; and the more extraordinary instance quoted by
Dr. Darwiu, in his ingenious work the Phytologia, of the
gates of the old St. Peter's church in Rome, which were
said to have contiuued without rotting from the time of the
emperor Constantino, to that of pope Eugene IV, a period
of eleven hundred years. On the other hand, wood will
remain for ages with little change, when continually im-
mersed in, water, or even when deeply buried in the earth ; underwater,
as in the piles and buttresses of bridges, and in various mo- dn m eart '
Tasses. These latter facts seem to show, that, if the access of
atmospherical air is not necessary to the decay of wood, it
is, at least, highly conducive to it.

In posts fixed in the ground and exposed to the weather, Decays soon *>»
we constantly find that part soonest decay, which is j ust *f *{j^ gVoSnd,

above

330 ON PRETEXTING THE DECAY OF WOOD.

«r-where moi- *bove or within the ground. So also where there is an ac-
**"re wzy cidental hole in an exposed surface, or any artificial cavity,
as in a mortice and tenon, or the part where pales nearly
touch the rails on which they are nailed, there the wood
universally begins first to moulder away. The same thing
happens with regard to horizontal rails themselves, which,
when made of the same materials, rot much sooner than the
pales which they support. These facts are very easily ex-
plained. They clearly show, that the great cause of decay
is the constant action of water aided by air, which most af-
fects those points, where it is most retained, but has less
operation, where, as in the perpendicular pales, it chiefly
runs off by its own gravity, so that the little which remains
is easily and quickly abstracted by the cooperating power of
the sun and wind.
This owing to The change which I am describing is the consequence of
pu re action, putrefactive fermentation ; a chemical operation, in which
the component parts of the wood form new combinations
among themselves, and with the water which is essential to
the process. The precise nature of these new compounds
has not been ascertained ; but, so far as they are known,
they consist of certain gasses, or species of air, which fly off,
and leave behind a powder, consisting chiefly of carbon or
charcoal, and the earth which entered into the original com-
position of the wood.
Water acts me- Beside this chemical change depending on water, that
substance tends to destroy wood exposed to the open air by
a mechanical operation. Every farmer is acquainted with
the power of winter in mouldering down the earth of his
fallows. It is equally well known, that porous freestone
splits and shivers during severe winters. These effects are
produced by frost, which, acting on the water in the pores
or interstices of these substances, expands it by conversion
into ice, and thus bursts the minute cells in which it was
contained. There can be no doubt, that a similar operation
takes place to a certain extent in exposed wood, and thus in
some degree promotes its destruction.
Water and air It appears, then, that the contact of water and air are
the chief m- ^ chjef causes 0f the decay of wood. If, therefore, any
means can be devised, by which the access of moisture and

ajr

ON PREVENTING THE DECAY OF "WOOD. 331

a?r can be prevented, the wood is so far secure against de- therefore to b»

mi* . • . i. -ii * i u • excluded,

cay. a his principle may be illustrated by supposing a cy-
linder of dry wood to be placed in a glass tube or case,
which it exactly fills, and the two ends of which are, as it
is called, hermetically sealed, that is, entirely closed by
uniting the melted sides of each end of the tube. Who
will doubt that such a piece of wood might remain in the
open air a thousand years unchanged? Or let us take a still Thus amber
more apposite illustration of this fact; that of amber, a^ts^&c.11*"
native bitumen, or resin, in which a variety of small flies,
filaments of vegetables, aud others of the most fragile sub-
stances are seen imbedded, having been preserved from de-
cay much longer probably than a thousand years, and with
no apparent tendency to change for ten times that period.
Let us see then if we cannot, by the exclusion of moisture
and air, find means of virtually placing our timber in a case
of glass or amber.

With this view, various expedients have been employed, Paint employ*
of which the most common is covering the surface with yiew'
paint ; which is oil mixed with some substance capable of
giving it the colour which we desire. It is well known, that
several of the oils, as those of linseed, hempsced, &c, be-
come dry when thinly spread on any hard substance. The
drying quality is much assisted by their being previously
boiled with certain metallic oxides, more especially that of
lead, litharge. The crust so formed is with difficulty pe-
netrated by moisture or air. For this purpose drying oil is
Spread on silk or linen, in the manufacture of umbrellas;
and will tolerably well succeed in confining hidrogen gas,
or inflammable air, in the construction of air-balloons.
Hence we see the mode in which the application of paint on
wood serves to defend it against the causes of destruction.

When paint is employed within doors, it is customary to Uses of oil of
add to the oil, beside the colouring matter, some essential .tturI)entme m
oil of turpentine, which not only makes it dry more rea-
dily, but, by giving it greater tenuity, causes it to flow
more freely from the brush, and therefore to go farther in
the work. For the same purposes I observe it forms a part
of the paint used on wood and iron work in the open air;
Jjut, as it appears to nie, roost improperly : For I have re- its disadvan-

marked^**-

S3<£ ON PREVENTING THE DECAY OF WOOD.

marked that on rubbing wood painted white, and long ex.
posed to the weather, the white lead has come off in a dry-
powder like whiting ; as if the vehicle which glued it to the
wood had been decomposed and lost, leaving only the pig-
ment behind: And I have been much iuclined to suspect,
that this has arisen from the oil having been too much
ope?iedy as the workmen call it, or having its thickness and
tenacity too much diminished by a superabundance of the
oil of turpentine. In this state it may, in various ways,
Acts similarly be more readily acted on by water and air. We know, that
in discharging ^ properties of what are called unctuous or fat oils are
much changed by the admixture of the volatile or essential
oils. On this principle we succeed in getting grease out of
woollen cloths by oil of turpentine ; bnt whether the same
change is produced on the drying oils, I have not learned.
Is the pigment It appears, then, that these drying oils either by them-

Or usf* '

selves, or boiled with metallic oxides, will form a varnish
on wood ; but it may be questioned how far the colouring
matters, with which they are usually mixed, contribute to
increase their preservative power. I do not however, deny,
that they may be serviceable in this and other views. They
might be supposed to enable the oil to lay firmer hold, as it
were, on the wood; and they may serve to increase the
thickness of the defensive covering. The first of these
This doubtful, points is of some importance ; for we observe that the paint
on street doors, which is become thick by frequent incrus-
tation, is apt, from the strong influence of the summer's
sun, to separate from the polished wood beneath, and rise
in large blisters; probably in consequence of a greater ex-
pansion in the crust itself than in the subjacent wood.
Here, therefore, the colouring matter of the paint fails to
produce the desired effect; and as to the second end, or
that of increasing the thickness of the covering, that may,
probably, be much more effectually accomplished than by
the mere addition of pigments, some of which are capable
of chemical decomposition, and all are costly. This pur-
Road dust. Pose an ingenious artist has of late attempted to answer, by
recommending an admixture of road-dust; and for that and
other means of reducing the price of paints, has obtained

3 premium

ON PREVENTING THE DECAY OP WOOD. S3S

ft premium from the London Society of Arts*. However just
the general principle in this case may be, the application is
somewhat unphilosophical; unless it shall be found, which
will scarcely be admitted, that dust of every chemical and
mechanical quality will equally or sufficiently answer the in-,
tended purpose.

Some material of this kind, selected with greater^ pre- Perhaps fine
cision, may however undoubtedly be useful ; and none I *[Je pre er"
think promises more fairly than siliceous or flinty sand,
which, so far as we know, is absolutely indestructible, and
which may be easily procured from the sea-shore, and from
the currents of the clear rivers and roads in Berkshire and
other counties abounding with siliceous stones. Sand from
the sea must first be cleared from all saline impregnations
by washing in several waters ; and any sand may be ob-
tained of the fineness desired, by mixing it with water in a
, tub, and after having stirred the whole well together,
pouring out, in a longer or shorter time, the muddy water,
from which the sand will settle by its own gravity, in a state „
fit for use when dried.

More than thirty years ago this subject presented itself to Water-shoots
my mind, on seeing some water-shoots, which had been
pitched and painted in the common way, taken down in a
state of complete rottenness. I had read that charcoal, bu-
ried in the moist earth, had come down to us perfectly
sound from the times of the Romans ; and that posts long
withstood the same moisture, if the part intended to be put
into the ground was charred all round to a certain depth.
Impressed with these facts, I determined to try an arti- Covered with

final coat of charcoal; and when new water-shoots were J?"!5 oll» an'!

tins dusted with
constructed, I strongly and carefully rubbed them with a charcoal.

coat of drying oil, which I immediately dredged all over
with a thick layer of charcoal finely powdered, and con-
tained in a muslin bag. After two or three days, when the
oil was thoroughly dried, and firmly retained the greatest
part of the charcoal, I brushed oft' what was loose, and
over that which adhered I applied a coat of common lead-
coloured paint, and a few days after, a second. The

* See Journal, Vol. XIV. p. 258.

whole

answer.

334 ON MtmSTINfi TRE DECAY OP WO#D;

whole became a firm and solid crust ; after which the shoots
vere put into their places,, and beii*£ examined many jears
afterward, appeared perfectly sound. Any other colour
would probably have succeeded equally well with that
Lamp black which 1 employed. I do not think that lamp black, which
rood Sn°tS0 IS a Pure sPecies °f charcoal, would have answered the
purpose of forming a thick defensive covering so well as the
grosser charcoal which I used. But whatever sort of char-
coal is employed, it ought either to be fresh made, or heated
again in close vessels, so as to expel the water which it
greedily attracts from the air.
Drtins oils ex- To all compositions formed from drying vegetable oils
pensive. there is this objection ; that however well they may answer

the end proposed, they arc too dear for that great con-
sumption, which is usually required for outside work. For
this and other reasons, various other substances have been
employed fop the same purpose.
Pitch does not Of these the most common is pitch, which is well known
to be the resinous matter melted by heat out of the pine
tribe of trees in form of tar, and afterward hardened by
evaporation. It is applied hot, and when cold, makes a
moderately hard varnish. It does not however appear, in
fact, to answer the purpose so well as might have been ex-
pected. The sun at first melts it, so that it runs ofl in
drops, or adheres to every thing which touches it; and the
united influence of air and water seems to make it brittle
and powdery like resin. Experience therefore shows it to
be of little value. Neither is it probable that its powers
would be much improved by admixture with charcoal, sand,
or other similar substances. Many members of this So.
ciety may recollect its application twenty years ago on the
red-deal shingled roofs of part of our market. In this
case it was used hot, mixed with Spanish brown, and har-
dened by sand sifted over it with a sieve; notwithstanding
which it seems to have left the wood like the unmixed
pitch, and, though frequently renewed, has not preventer
the necessity of various repairs within these last five years.
The original boards are now every where more or less in a
state of decay.

Th#
/

ON PREVENTING THE DECAY OF WOOD* 335

Tbe bituminous substance melted by heat out of coal, Coal tar.
and commonly called coal tar, lias been strongly recom-
mended for this purpose by that ingenious philosopher
Lord Dundonald. I have tried it largely and unsuccess-
fully, though perhaps not fairly ; for the workman whom
I employed, in order to make it work more easily, added
to it oil of turpentine, which certainly diminished its du-
rability by rendering it more miscible with water. I am
however inclined to believe, that no substance of this kind,
used by itself, will become sufficiently dry and hard to resist
the influence of the weather.

As animal oils are considerably cheaper than those ex- Animal oils
pressed from vegetables, attempts have been made to com- ma e rying'
municate to them a drying quality. This has been effected
by dissolving in them while hot various substances capable
of being melted, in such a portion that the whole mass
would become dry and hard when cold. Bees' wax, resin,
and brimstone are found to have this property. Some of
them, when united with drying oil, have long been em-
ployed for making boots and shoes water-proof, or im-
pervious to moisture^. But they will also succeed when
mixed with train oil, which is obtained from the blubber of
the whale. In the second volume of the Memoirs of this
Society, printed in the year 1783, there is the following
receipt. " Melt twelve ounces of resin in an iron pot or Composition q*
kettle; add three gallons of train oil and three or four, ort'
rolls of brimstone; and when the resin and brimstone are
melted and become thin, add as much Spanish brown, or
red or yellow ochre, or any colour you want, first ground
tine with some of the oil, as will give the whole as deep a

* For this purpose there is the following receipt by Mr. Barker Old receipt for
in Sir John Hawkins's edition of that entertaining work, Isaac ^ater-Pr°of
Walton's complete Angler: 4th edition, page 223. " Take a pint
of linseed oil, with half a pound of mutton suet, six or eight
ounces of bees' wax, and half a pennyworth of resin. Boil all this
jn a pipkin together ; so let it cool till it be milk-warm. Then take
a little hair-brush, and lay it on your new boots ; but it is best that
this stuff be laid on before the boot-maker makes the boots ; then
brush them once over (with it) after they come from him. As for
•Id boots, you must lay it on when your boots be dry."

4 shade

236 °* PREYENtlXG THE DECAY OF WOOtf.

shade as you like. Then lay it on with a brush as hot anil
thin as you can. Some days after the first coat is dried,
give it a second. It will preserve plank for ages, and
keep the weather from driving through brick-work."
Page 114.
Tried with ap- This composition I tried about eighteen years ago on
paren success. gQmc cjm paffj^ substituting for the colouring matter one
or two coats of common white paint for the sake of the
appearance. This paling appears to me to be in every
part of it, which was so covered, as sound as when it was
first put up.
Bees wax ad- As compositions of the resinous kind are apt to crack
and become powdery, like the varnish of carriages, by ex-
posure to weather, it is not improbable, that this effect may
be in some measure counteracted by the mixture of a small
proportion of bees' wax. Such a compound I have used,
but in the quantity of eight ounces to the gallon found it
too slow in drying, and capable of being easily scraped oft*
with the nail. Wax is also at this time very scarce and
dear*.
Remarks. All the substances contained in these mixtures are ca-

pable of perfect incorporation with each other by heat, and
v when separately exposed, are with great difficulty acted on
by water or air in any heat which occurs in our climate.
Method of ap- They should be applied hot with a common painter's brush
p ica ioa, ^^ t^e wood which is previously very dry, so as to sink

deeply into its pores ; and though at first they arc appa-
rently somewhat greasy when cold, yet after some days
they make a firm varnish, which does not come off on rub-
bing. Wheu it is required to give beauty to the work, co-
louring matters may either be added to the mixture, or af-
terward applied over it in form of common paint. Two

* For the information of those who may be inclined to make a
trial of these compositions, I have inquired the wholesale prices of
the different ingredients of Messrs. Cave and Co. Bristol, from
whore I learn, that they are ,very fluctuating, train oil being from
2*. 3d. to 3s. 2d. per gallon ; resin from 12 to 21 shillings per cwt. ;
roll brimstone from 34 to 38 shillings per cwt. ; and bees' wax from
3s. 3d. to 3s. 6d. per lb. ; the lowest of these prices being about
what these articles at present bear.

coats

ON PREVENTING THE DECAY OP WOOD. 337

coats of the composition should always be given ; and in
all compound machinery, the separate parts should be so
Tarnished before they are put together ; after which it will
be prudent to give a third coating to the joints, or to any
other part which is peculiarly exposed to the action of moi-
sture, such as water-shoots, flood-gates, the beds of carts,
the tops of posts and rails, and all timber which is near or
within the ground. Each coat should be dry before the
parts are joined, or the last coat applied.

These compositions are equally efficacious in keeping it would pre-

iron from decay by rusting. They might also be very ad- serv,e iron» and

i i j- j • T x- ix xi. , , render arches

vantageously employed in rendering water-tight the plaster, impervious to

which is used to case the outside of the arches of vaults water«
unsheltered by roofs, provided the mortar were made per-
fectly dry, and the covering of the arch brought up to an
angle, instead of making it follow the form of the arch in
an elipse or the segment of a circle.

It is necessary to mention, that compositions made of Caution,
hot oil should for the sake of security be heated in metallic
or glazed earthen vessels in the open air. For whenever
oil is brought to the boiling point, or 600° of Fahren-
heit's thermometer, the vapour immediately catches fire,
although not in contact with any flame; and though a
lower degree of temperature than that of boiling should be
used in this process, it is not always practicable either ex-
actly to regulate the heat, or to prevent the overflowing of
the materials, in either of which cases, were the melting
performed in a house, the most fatal accidents might
follow.

The following is the proportion of the above ingre-
dients, an^ the mode of mixing them, which I should re-
commend.

Take 12 ounces of resin, and 8 ounces of roll brim- Mode of mak-
stone, each coarsely powdered, and 3 gallons of train-oil. r,ir the comP°-
Heat them slowly, gradually adding 4 ounces of bees'-wax,
cut into small bits. Frequently stir the liquor, which, as soon
as the solid ingredients are dissolved, will be fit for use.
What remains unused will become solid on cooling, and
may be remelted on subsequent occasions.
Vol. XIX.— Svwmment. Z If

338 *N «« BLIGHT IN WHEAT.

Charcoal pow- If the addition of charcoal powder or siliceous sanii
Her or sand may contributes to the durability of drying oiI9 it may pro*
bably have a similar effect on this composition ; but whe-
ther it may be best to mix them with the ingredients, or
apply them afterward, I cannot from experience tell. In
the latter case, the powder should be sifted on, while the
first coat of the composition is still hot ; and, after some
days, when that is dry, should have a brush gently passed
over it, in order to remove all the particles which do not
adhere ; after which other coats of the composition may be
applied, as before directed.

This is all which occurs to me as to the mode of pre-
serving wood when exposed to the weather.

(To be concluded in our next.)

III.

On the Blight in Wheat, By Mr. Thomas Davis, of
Horningsham *.

^tfheat Wight a JL HE opinion I gave in the Bath Society's Papers,
plant. yo^ x^ p 41^ that thc wjjeat blight is a plant, and not

an insect, is now fully confirmed by the microscopical ob-
servations of that able naturalist, Sir Joseph Banks, who,
in his treatise on the subject, has given magnified repret
sentations of the plant, in which its form and fructification
are so conspicuous, that no one can doubt the fact +.

Sir Joseph also describes the manner in which the mi-
nute seeds of this plant (which are as light as air) are car-
ried by the wind, and lodged on the growing stalks of
wheat, where they take root and vegetate, and, like all
other parasitical plants, rob the plant to which they at-
tach of its nourishment, to support themselves. The ef-
Its destructive ^ec* is *00 we^ known. The rapidity with which these
operation. minute plants vegetate, and the destruction they make in a
crop of wheat, of which the ears only a few days before

* From the Bath Society's Papers, Vol. XI, pill.
t See Philos. Journal, Vol, X, p. 225, and Plates IX, X.

appeared

ON THE BLIGHT IN WHEAT. 33J

appeared full and heavy and nearly fit for the sickle, can
scarcely be believed by those who have not observed it, and
is astonishing even to those who have watched its progress.
It seems to produce something more than a mere cessation
of growth. Its action is like that of poison. It p.bsorbs
the farina or flour of the fairest and plumpest grain, and
reduces it to a mere shell of bran.

But although the nature of this disease is now so well Remedy 4if-
known, the remedy is not so easily found. With all due
deference to the great abilities of Sir Joseph Banks, I am
not so sanguine as to expect, that it can be eradicated by
pulling up the diseased plants: or even, if it were practi-
cable, by burning all the straw of every blighted crop.

The seeds of this destructive plant arc too minute and
abundant, and capable of being wafted to too great a dis-
tance, to be totally destroyed. A single acre of blighted
wheat will produce seed enough to supply a whole district ;
and indeed it is too well known to botanists, that the plant The plant not
grows and flourishes on many other plants beside wheat, confined to
And were there but a single piece of wheat in a country
where none had grown before, the enemy would be ready

for the attack, whenever there was a predisposing cause in Predisposing
,, , . . cause to be

the wheat crop to receive it. guarded against.

It is probably not within the power of man to prevent,
totally, the ravages of this destructive, though minute
enemy to agriculture, but it may yet be in his power to
reduce them in a considerable degree, by ascertaining and
obviating the causes zchich peculiarly dispose and prepare
the wheat plant for its attacks. These may be summed up This debility.
in one word, viz. weakness, or debility.

The class of plants called by botanists mosses and lichens Mosses and Ji-
are the insects of the vegetable kingdom, created to prey on w^us^Tin-
tceak plants, as the insects of the animal kingdom, are to sects.
prey on zceak animals. In both instances, the juices by
being weakened and deprived of their acridity become their
proper food. The remedy must be to restore to the object
its natural health and vigour.

To apply this argument to wheat, and to show the cause s
which render it unproductive, it will be accessary to con-

Z % lider

340

Mode in which
wheat grows.

An irregularly
ripening crop
subject to
blight.

Thin and late
crops particu-
larly so.

Causes that
render wheat
weak.

ON THE BLIGHT IN WHEAT.

sider the nature of the plant, and the kind of cultivation
which usually renders it productive.

It is well known, that nature has furnished the wheat
plant with a double set of roots, so contrived, that the first
may be deep enough to enable it to stand the severity of the
winter ; and the second so shallow as to admit the genial
influence of the spring. It first shoots down a perpen-
dicular tap-root, which supports the plant and keeps it
steady during the winter; and in the spring it tillers out a
number of coronal shoots, each of which has its own proper
root, and produces its ozen ear, though still adhering to
and dependent on each other for mutual support; and when
that operation is complete, the winter root becomes useless
and dies.

If this winter root be imperfect, the side shoots which
arc to produce the crop will also be so. A strong solid
foothold for the tap-root is therefore necessary for wheat ;
and the more complete the winter root is, before the spring
tillering takes place, the more perfect will be the crop. If
the formation of the young plants be unequal, so will be
the ripening of the crop ; and if the ripe ears on one part
of the plant are waiting for the green ones on the other, the
blight generally attacks the crop.

A thin crop of wheat, and a late ripening crop, (and a
thin crop is usually a late ripening one,) are the peculiar
prey of the blight ; and these are generally produced either
by sowing land with wheat, which is unfit for wheat, or in
an improper state of cultivation, or by sowing it in an im-
proper season. In fine, any cause which tends to weaken
the plant, will predispose it to receive the blight.

The causes which tend to weaken the wheat plant are
many, but the following are the most obvious :

1*/. Sowing wheat on land that has been so worn out by
cropping, as to have lost that tenacity and cohesion, which
are so necessary to a wheat crop, and which even dung,
without rest, will not restore.

Idly. Sowing the land in a light loose state, whereby the
wheat plant roots too near the surface, and is liable to be
injured by the winter's frost, and to have its roots laid
bare by the wind,

Zdly.

.ON THE BLIGHT IN WHEAT. 341

3dhj. Sowing wheat too late in the autumn, (which is
too common,) especially in poor land and exposed situa-
tions, where the roots have not time to establish them-
selves before the winter comes on, and vegetation is totally
at a stand.

Now as these causes have, in consequence of the ad- Probably Jn-
Tance in the price of wheat, occurred more frequently 0fcrease<l°f late.
iate years than formerly ; it is probable that the assertion
u that the blight on wheat has increased of late years"
may be true. For,

1st. It has not been uncommon to sow land with wheat From sowing

every third year, instead of every fourth or fifth: and as wheatto° fre-

, quently,

the land, in the interim, has been under crops, the very

nature of which is to make land light, and no fallow year
having been allowed to get it close again; the crops,
though abundant in straw, have not had strength enough to
support them till harvest, and have been laid by the rains,
and thereby become a prey to the blight.

c2d. It has been, very much the practice of late years to or after tur-
sow wheat after turnips, and very clean crops have been mps'
produced thereby. But this system is wrong: the tur-
nips arc eaten before they are wanted, and the wheat is
sown a month too late; and being necessarily late ripe , is
often attacked by the blight.

3d. It has been also a frequent practice to sow wheat or after pota-
after potatoes; and this system is still worse: the land is toeb*
rendered too light for wheat, and the seed time is much too
late, unless it be in deep rich land, where the wheat plants
will grow during the whole of the winter.

4th. And even the practice of sowing wheal after clover and in some
has been carried to too great an extent on light land; espe-cases c over"
daily where the land is nearly tired of clover. It en-
courages the slug, and the wire-worm, which destroy a
considerable part of the wheat plants, leaving the residue a
thin unequal crop, which the blight seldom fails to attack,
and frequently to ruin.

To sum up the whole: — If it can be proved, (and every General direc-
man who is a farmer must have observed it,) that all ueaktlons*
crops of wheat, and particularly all late-ripe crops, are
peculiarly subject to Ulight; it should be the great object

of

842 ON *H* BLIGHT IN WHEAT.

of every farmer to sow such land, and such only, to wheat,
as is fit for wheat ; to get it in order early in the summer,
that it may be close and firm before sowing ; to sow as early
as the state of the weather will permit, particularly in cold
soils or exposed situations ; and to sow those kinds of wheat,
which arc disposed to ripen early, (a circumstance much
more attended to in Scotland than in England;) but above
all, not to wear out his land by cropping it oftcner with
wheat than its nature will bear ; always considering, that
it is not the number of acres sown, but the number of
bushels produced, that will enrich the farmer, or supply the
market.

Blight in some When I assert that weak crops are the most susceptible

cases mcreased of flight, I do not altogether mean such crops as are weak
in consequence of a zcant of manure, but such as grow on
land which has been made so light by repeated culture, that
the plants cannot get firm foothold, the great desideratum,
in fact the sine qua non of a good wheat crop ; and ma-
nure, particularly horse-dung, instead of remedying this
defect, only adds to the evil. In this instance, the remark
which has been often made, that the highest manured crops
are the most susceptible of blight, is perfectly consonant
with my observation. For the same reason, these crops
are apt to fall before they are ripe, and in that situation if
there be any blight in the air, they are sure to be infected
with it, because the sun cannot dry them, and the circula-
tion of the sap is impeded by the bruising of the straw.

Too much ma- It Avas well observed in one of the Agricultural Re-
ure injurious j)0r^ " that land may be made so drunk with dung, that
a wheat crop cannot stand upon it :" and I will defy any
man to get a good yielding crop of wheat in a highly-ma-
nured garden. He may, and probably will, get a good
crop of straw.

Wheatoncer- Mr. A. Young is right, in saying in his Annals, that

lain lands sel- on hj„h ]and, not of the best quality* wheat is seldom
dom blighted. , ,

blighted. The reason is, that such land is not made too

loose by culture and manure, and the straw stands upright
Instances of and exposed to the sun and wind. I had a very striking in-
flight on ,and stance of this on the Marquis of Bath's land, under my
loosened too ' J

much by cul- care, a few years ago : I had ploughed up twenty acres of

furze-

ON THE BLIGHT IN WHEAT. 343

furze-land in the autumn, with intent to sow it to wheat, ture and ma-
It was run back in the spring, and cross- ploughed early innure*
the summer, so as to be quite close and firm before wheat
sowing; but having occasion to plant two acres of po-
tatoes, I took part of this land and manured it well with
rotten dung, and planted the potatoes therein. They were
ripe early, and when dug, the two acres were sown with
wheat; on the same day, the rest of the piece, which had
not been dunged at all, was sown. The wheat on the two
acres was much the proudest during the winter, and the
best crop when it came into ear ; but when it was just ripe,
(which Was ten days after the other part,) the blight struck
it, and it was as black as a coal, while the rest was as
bright as silver. In fact the two acres were scarcely worth
reaping.

Again, with respect to late-ripening crops being subject Ripening a ces-
to the blight, I am of opinion, that the act of ripening sation of action.
wheat and all annual graminiferous plants is not so much
an effort of nature, as a cessation of nature's efforts ; and
that no crop of grain can be a good one, unless the whole
ripens together ; and if by any cause, particularly by the
seed being sown too thin, or by a partial failure of the
plants from a severe winter, the plant is forming new
roots, or one part of it is doing so, while the other is or
ought to be ripening its seed, the straw keeps green and
moist, instead of turning yellow and dry, and the blight is
sure to take it. And this has brought drilling into dis- Circumstance*

grace more than all other causes, particularly when the?6114111?.1,?'
i » . * % « brmS driving

crop has been sown too thin, or the hoe has been used too into disrepute
late*.

* I have just been a witness to the threshing a piece of drilled
wheat, which was injured by harrowing in grass seeds in April j the
harrowing made the wheat too thin, and caused it to throw out new
shoots ; it kept growing while it ought to have been ripening ; it of
course took the blight, and though the ears were six inches long*
the produce weighed only 40lb. per bushel

IV. Jnszcer

AXSWER TO REMARKS ON MR. YXNCE'S PAMPHLET.,

IV.

Object of Mr.
Vince's pam-
phlet.

The principal
objection
founded on 3
mistake.

Anszcer to Remarks on a Pamphlet, lately published by
the Rev. T. Vinck, respecting the Cause of Gravitation*
In a Letter from the Author.

To Mr. NICHOLSON.

SIR,

X Observations on the Cause of Gravitation having
been attacked in the last number of your Journal, by a
person calling himself Dytiscus, you will, I trust, do me
the justice to admit my answer in the next.

What I proposed to establish was, that the fluid as-
sumed by Sir J. Newton as the cause of gravitation can-
not produce a force to impel a body towards the sun, which

shall vary as — . The principal objection is to the 18th

article, in which it is said, "hence, according to the fore-
going reasoning, taking only the two first terms of the
series, &c. &c." In the foregoing reasoning we took «>«
for the density of the medium, and then the force was re-
presented by the sum of the alternate terms of the Binomial
theorem ; in this particular case, therefore, we take the
two first terms only, as is here proposed. But in the pre-
sent article we represented the density by P ff>«-|-Qa7-f-
It «7+? kc. each of which terms gives a series for the force,
similar to that stated above ; here, therefore, according
to the same proceeding, we take the two first terms of each
of these series. This must be the meaning of the words,
" taking only the two first terms of the series ;" for they
must mean, either the two first terms of each of the series
composing the whole force, or the two first terms of the
whole considered as one series. But the latter meaning
would have entirely ex. luded all the other series for the
force, arising from the general law of density Prt'«-j-Q«?
~f-Rar+, &c. continued to an indefinite number of terms,
ind which it was the declared intention of the proposition
to take inland here confined the force to two terms only,
Pa^4-Qa7. It would, therefore, have been totally in-
consistent with the terms of the proposition^ to have taken

the

%NSWER Td REMARKS ON MR. VINTt'S PAMPHLET. 345

the words in the latter sense, as it would have destroyed it
as a general proposition here proposed for investigation,
and reduced it to a particular case, besides, the two first
terms of the whole as forming one series would not have
had a definite meaning ; for we might write down all the
first terms of each series, and then all the second terms, in
their order: or, we might write down the first and second
terms of the first series, and then the first and second terms
of the second series, and so on. As the terms of each
series are the alternate terms of the binomial theorem,
the first terms only of the first three series were put down,
with -J-, &c. showing that the other terms were to be under-
stood. Two terms only of each series were proposed to
be taken, to show, even upon that supposition, that as
different powers of a must then enter into the two first
terms of each series. The whole could not constitute a

quantity which should vary as — . But Mr. D. seems to have

paid no attention to the words, u taking only the two first
terms of the series," nor to have considered that the word
series is used in both numbers; and hence, instead of
taking the first and second terms of each series, he has
taken the first terms of the two first series, leaving out the
second terms which it was proposed to take in, and thus
(to use his own expression) u committed so palpable a
blunder," as totally to do away the whole force of his
objection.

But Mr. D. goes on thus : cc on this point the professor's Another mis-
whole demonstration rests." This is another most un- take Pomtfed

out.
fortunate mistake, and contains a further proof, how little

Mr. D. attended to the subject. What is here assumed, is
only a very near approximation to the force, but still suf-
ficient for our purpose; the correct law of the force is
obtained by taking in all the terins of each of the series,
instead of the two first only. And the proof of my pro-
position further rests upon this, that the density of the
planet enters into the expression for the force; on which
account it was not necessary for me to have gone any fur-
ther in the investigation than the 13th article; here I have
fully established my proposition: but the subject being

new,

846

The objection
proves nothing
•gainst the pro-
position.

Farther exami
nation of the
objection.

The second
objection an»
swered.

ANSWER TCJ REMARK* CfN MR. VINCE'l »AMfHEt<;

ftety, and of a Curious nature, I was induced to consider
it a little further.

If, however, Mr. D's objection had been well founded,
it would hate prored nothing against my proposition, a°
his own conclusion shows, that the force does not vary as

— p the density e entering into the expression for the force.

Upon his own assumption, taking in all the terms of the

series, the force will be represented under this 'form;

a (T y l

— 4-— ^.A - + &c. and cart this vary as , even

«2 a* a6 J a2 '

omitting e ?

But there is another ground upon which we may examine
the objection. The quantity Pa"»-|- Qa? -j-Ra^-j. . &c.
representing the density of the fluid, must always be
positive ; hence P, Q, R, &c. m, gr, r, &c. are under certain
restrictions, such as to make the above quantity positive
for every value of a. Now we must have some standard for
our quantities. Let, therefore, the sun's radius=l, the den-
sity of the fluid at the sun's surface = 1. Now according to
Sir J. Nczrtori's hypothesis, the fluid pervades the sun,
causing thereby the gravitation within as well as without
the sun. Also, a varies from o to infinity. Now ac-
cording to Mr. D's assumption of Q, m, q, the density of

Q

the fluid is represented by P ; when, therefore, by di-

Q

minishing c, — 5- becomes greater than P, the density of the

fluid becomes negative, that is, there is no fluid, and con-

Q n

sequently no gravitation. Make P — — - = o, and «=v/-i*

a p

From the centra of the sun, therefore, to this distance,
there is no fluid: hence, according to Mr. D's assumption,
part of the sun is not endued with gravitation ! he has
therefore made an illegal assumption of the quantities Q7
my q; what then becomes of his objection?

But he has brought forward another objection. He
says, I ought to have used 3 m, 3q, for 2 m. 2 q ; this, he
asserts would have bein the ckse5 if I had estimated the

density

ANSWER TO REMARK5 ON MR. VINCfc's PAMPHLET. J4T

density of the fluid as Newton did, that is, by the quantity
of matter in a given cubical space. True ; but the nature
of my proposition necessarily obliged me to measure the
density by the quantity of matter on a given plane; my
2 w, 2 q, are therefore perfectly correct, and this is no
new use of the term density ; it is so used when we say the
density of light, heat, &e. varies inversely as the square of
the distance. With so little attention did Mr. D. examine
my investigation, as not to see, that I was under the ne-
cessity of so estimating it on the ground I took ; for he im-
putes it to a mistake, that I did not estimate it as Nexton
did. Is not this a M palpable blunder r".

From -an attentive consideration of what is advanced by The objector
Mr. D., I am clearly of opinion, that he did not read the f^ ^oleoTt!^
whole of the essay, so as to comprehend the true grounds investigation.
upon which the truth of my proposition rests. He seems
only to have looked amongst the expressions, to see, if by
assuming particular values of the quantities, he could not
prove against the proposition; imagining that such values
were unlimited, and altogether misunderstanding the sub-
ject. If I am wrong in this conjecture, his mistakes must
have arisen from his not having mathematical knowledge
sufficient to comprehend the investigation.

The truth of my proposition rests upon two independent
circumstances — that the density e of the planet enters into
the law of force; and that by taking in all the terms of the
scries expressing the force, it is impossible to make the force

vary as — , even omitting e. What then becomes of H#b>

D's vaunting assertion, u on this point the Professor's
whole demonstration rests." From the scientific knowledge
displayed by Mr. D. in his animadversions on my essay, we
are justified in applying to himself his own words, muta-
tis mutandis ; " the errours in the works of Dytiscus afford
no very flattering specimen of the mathematical abilities of
this country."

He further objects thus: " what he says respecting the What was «aid

interference of the ethereal atmosphere of the different °^thee,the'ea?'

r atmospheres of

planets is totally foreign to the question." Not totally the planets an

foreign; for it makes directly against the existence of such ^^their
, an existence.

*4S

STOMACH dP THE WHALE.

The reviewers
vindicated.

in atmosphere, so far as wc have any experience of elastta
fluids.

Mr. D. is very angry with the Reviewers, that they were
not so quick-sighted as himself, in discovering the faults
in my essay ; what has here been said may, perhaps, tend
a little to explain the reason.

The information, that my paper might probably not be
printed, came from the Secretary, Dr. Grey; this Mr. D.
acknowledges was not prudent conduct. But I conceive
myself to have been also very uncivilly treated on this
account, that the Secretary, whose duty it was to have in-
formed me how my paper was disposed of, never com-
municated to me the information. Having had occasion to
mention Sir J. Pringle, and not having been aware of any
circumstances, which ought to have prevented me from
Stating my opinion of his character, I thought it proper to
pay him a mark of respect, justly due tm his memory.

I am, Sir,
Your obedient Servant,

S. VINCE.
Cambridge,
April 6th, 1808.

Object of m«
author.

V.

Observations on the Structure of the different Cavities,
uhich constitute the Stomach of the Whale, compared with
those of ruminating Animals, zcith a Vzcxz to ascertain
the Situation of the digestive Organ. By Everariv
Home, Esq.F.R.S.*

A HE following observations are in some measure a con-
tinuation of those upon the stomachs of ruminating animals
contained in a former paper. They are intended to show
that the stomach of the whale forms a link in the gradation
toward the stomachs of truly carnivorous animals.

* Abridged from the Pliilos. Trans, for 1807, Part I, p. 93.

The

STOMACH OF THE WHALE. 349

The number of cavities constituting the stomach are not Stomachs of the
the same in all animals of the whale tribe. In the com- whaletube*
mon porpoise, grampus, and piked whale, the number is
the same as in the bottle-nose porpoise ; but in the bottle-
nose whale of Dale there are two more cavities. This va-
riation is however by no means material, since the general
structure of the stomach is the same.

In all of the whale tribe there is one cavity lined with a First cavity,
cuticle, as in the bullock and camel.

In all of them there is a second cavity made up of a very Second cavity,
glandular structure. In the porpoise, grampus, and large
bottle-nose whale this structure resembles that which is
above described. In the piked whale the rugs are longi-
tudinal and deep, but in some places united by cross bands;
and as the piked whale has whalebone teeth, the great
whalebone whale will probably, from the analogy of its
teeth, resemble it in the structure of its stomach.

The third cavity in all of them is very small, and bears Third cavity.
a strong resemblance to the third cavity in the camel's
stomach ; its use, therefore, is probably the same.

The fourth stomach in all of them has a smooth internal Fourth cavity,
surface, with the orifices of glands opening into its cavity.
In the bottle-nose whale of Dale the two additional cavities
have the same internal structure, and therefore must have
the same general use, with a greater extension of surface,
and the subdivisions will make the food pass more slowly
into the intestine.

The first stomach of the whale is not only a reservoir, .Office of the
but the food undergoes a considerable change in it."" ^fee first stonjach-
flesh is entirely separated from the bones in this cafity,
which proves that the secretion from the glandular paffchas
a solvent power. This was found to be the case in the
bottle-nose porpoise and large bottle-nose whale. In hoth
of them several handfuls of bones were found in the n*fst
stomach, without the smallest remains of the fish, to which
they belonged. The soft parts only can be conveyed frrto
the second and third stomachs, the orifices being too small
to admit the bones to pass.

The bones must therefore be reduced to a jelly in the
£ rst stomachj and although tke process^ by which this is

effected,

3b0 , STOMACH OF THE WHALE.

effected, being slower than that, which separates the flesh,
i9 the reason of their being found in such quantity in the
cavity, the means by which it is performed are probably
the same.
Mr. Hunter's The second cavity was supposed by Mr. Hunter to be
wconTcavity! tiie true WfiHfeg stomach, in which the food becomes
chyle, and the use of the third and fourth he looked upon
as iiot exactly ascertained*.
Erroneous. Upon what ground Mr. Hunter was led to draw this con-

tusion cannot now be ascertained ; and, such is my respect
for his opinion, that nothing but the following observa-
tions, supported by facts, could lead me to form a different
one. In considering this subject, it struck me that the
second stomach could not be that, in which chyle is form-
ed, since that process having been completed, any other
The chyle al- cavities would be superfluous. The last cavity in all
theT f°rmecjin stomachs is that, in which the process must be brought to
perfection : and therefore the most essential change, which
the food undergoes, or that by which it is formed into
chyle, should be performed in that cavity. Surveying the
different cavities in the whale's and ruminating stomachs
with this impression on my mind, and comparing them with
the single stomachs of carnivorous animals, it appeared
that the first point, which required to be ascertained, was,
which of the cavities in these more complex stomachs bears
the greatest resemblance to the simple one. 'The fourth of
the whale is certainly more like the human stomach than
the second or third. I therefore concluded, that the fourth,
both from analogy and situation, is the stomach in which
the process is completed : and that in this animal, from the
peculiarities of its ceconomy, and the nature of the food,
not only a cuticular stomach is necessary, but also two
glandular ones, in which it undergoes changes preparatory
to its being converted into chyle.
Compart -with Having satisfied myself upon this subject, and having
the stomach ef^ired the sfomac},s 0f the whale with the fourth of
the camel j

the camel, the contraction or partial division of the camel's

made it apparent, that the lower portion only of that ca-

* Fide Observations on the Structure and (Economy of Whale?.
By John Hunter. Philos. Trans. Vol. LXXVII, p, 411.

4 Thy,

STOMACH OF THE WHALE. 35 X

vity, which resembles in shape and internal appearance
the human stomach, is the cavity in which chyle is formed,
and the upper or plicated portion i3 onjy to prepare the
food, and is therefore analogous to the second in the
whale.

As the same appearances are met with in the fourth and of the
stomach of the bullock, as well as in the camel, although buliac^
there is no permanent contraction, or division betweea
them, the upper or plicated portion must be considered as
a preparatory organ, and the lower portion as that, in
which the formation of chyle is completed. This receives
farther confirmation from a more attentive examination of
the parts immediately after death, by which it was found,
that, before the stomach has been disturbed, there is a*
evident muscular contraction between the plicated an4
lower portion. This appearance was met with in everj
instance that was examined, and these were not fewer than
nine or ten. Ad4ed to this the lower portion, on a more
minute inspection, has an appearance somewhat similar to
the inner membrane of the human stomach : and the surface
of the plicae is in many respects different.

From the facts and observations which have been stated, Chyle pro-
it appears, that, in many animals of the class mammalia, similar Secre*#
the food undergoes different changes preparatory to its tion in a}l tnt
being converted into chyle, and this last process is effected
by a somewhat similar secretion, since the part of the
stomach which produces it has in all of them an evident
similarity of structure.

The above facts appear to throw some light on the diges-
tion of the different kinds of food, and open a wide field
of inquiry into one of the most interesting parts of the
animal ceconomy, which has been hitherto too much neg-
lected. In the present very limited state of our knowledge
there are many circumstances, which cannot be accounted
for : these however will be explained, when a further pro-
gress has been made in this investigation.

It is obvious, that as the stomachs of carnivorous animals Animal sub-
are the most simple, animal substances, on which they stances e"ier

r 7 ' f converted intq

feed, require a shorter process to convert them inte chyle chyle than ve-

than vegetables 5 but why the whale tribe; which live on setables«

fch,

from their
bones

S5g STOMACH OF THE WHALE.

fish, should hare a more complex stomach, it is not easy
to explain : since fish are very readily converted into chyle,
in the stomachs of animals of their own class, as well as in
the human stomach, and there is therefore reason to be-
lieve, that they require as little preparation for that process,
if not less than animal substances.
Ruminating The fish bones swallowed by the whale tribe being rc-

tf lirineorffisrf i^nc^ in tne cuticular bag, till they are reduced to jelly,
ithout injury explains the circumstance of cows, and other ruminating
animals being able occasionally to live on fish, (a fact, of
which there is no doubt, both in the Orkneys and in Ice-
land ;) since, if the bones are dissolved in the paunch, the
other stomachs are in no danger of being injured from the
animal living on this kind of food. I

Whether these cavities, which I have called preparatory
stomachs, are solely for purposes connected with digestion,
or are also in any way connected with the formation of
secretions peculiar to those animals, cannot be ascertained
in the present state of our knowledge of digestion.
Anomaly of The oil of the physeter, which crystallizes into sperma-

wnale.ermaC ' cc^t shows some affinity in this respect to the secretion of
fat, that becomes suet, which is only met with in rumi-
nating animals : but on the other hand, the oil of the rest
of the whale tribe does not form this substance, more than
the fat of the horse produces tallow. These facts may be
hereafter explained by an examination of the digestive
organs of the physeter, when an anatomist shall have an
opportunity of examining them.

VI. On

0* TAMILY WINT. MAKI.YG?. 35^

Vf.

On Family Wine Making. By W. Matthews. E*q. *,

To the Committee of Superintendance of the Bath and
Went of England Society*

Gentlemen,

AlAVING in the 10th volume of the Society's papers Hom« made
been indulged with the insertion of a few remarks on the '
utility of making family wines from several of our garden
fruits ; I took the liberty of presenting, at a subsequent
General Meeting, for its examination, a sample of suck
"wine made under my own notice. It will be within the re-
collection of different gentlemen, who attended that meet-
ing, that the wine they tasted w^as deemed a very good,
pleasant-flavoured, and useful article. The price at which
it was made + was considered as small, when compared with '

the uses to which the wine may be applied, even in genteel for family use,
families, where economy is regarded. But the idea of
making such an article, in considerable quantities, (espe-
cially in abundant fruit years,) so as to have the power of
furnishing sick and sickly poor persons with such occa- and the sick
sional refreshment, could not pass unapproved. The oldest Poor-
w ine of this sort which 1 now have by me, is yet too young
to give proof of that excellence, which three or four years
more will give it; but it is now so rich and valuable, that
I can have no hesitation about publishing the recipe, by
which it is made, and encouraging any of our members fully
to rely upon it for success. The fruits used were of the
different sorts mentioned in the recipe, excepting goose-
berries, and I think nearly of equal quantities, taken out
of a private garden, where they would otherwise have
turned to very little account. My friends having fully Goodness,
convinced me, that if I gave them white wine equally good

* Papers of the Bath and West of England Society, vol. XI,
p. 2?<2.

f This will be from 2s. (3d. to 3s. per gallon, according to cir-
cumstances.

Vol. XIX. — Supplement. 2 A with

354 ON FAMILY WINE MAKING.

with that produced, they will not call on me for foreign

white wine, of at leastyZre times the price ; I have this year

taken the advantage of a fine fruit season, and made several

Several hogs- hogsheads. If I live to present the Society with a taste

of it some years hence, I have no doubt of its being found

worthy of their commendation.

Black currants j cannot conclude without repeating my recommendation
recommended *■*•'. « '»» >

to the owners ot gardens in general, to all farmers m easy

circumstances, and country gentlemen especially, to regard
this useful practice : — and that they may do it to the greater
advantage, the increased cultivation of the black-currant
plant seems essential : It is easy to increase, greatly pro-
ductive, and its fruit, in general, can scarcely form too
large a proportion of the mixture.

I remain, with all due respect,

Your faithful coadjutor,

WILLIAM MATTHEWS.

Bath, September, 1807.

A useful Recipe for making Family Wine.
Receipt for the Take, black currants, red ditto, white ditto, ripe cherries,
"wme* (black hearts are the best) rasberries, each an equal, or

nearly an equal quantity: If the black currants be the
most abundant, so much the better. — To 41b. of the mixed
fruit, well bruised, put one gallon of clear soft water :
steep three days and nights, in open vessels, frequently
stirring up the mass : then strain through a hair sieve.
The remaining pulp press to dryness. Put both liquids to-
gether, and to each gallon of the whole put three pounds of
good, rich, moist sugar, of a bright yellowish appearance.
Let the whole stand again three days and nights, frequently
stirring up as before, after skimming oiF the top. Then
,tiiQ it into casks, and let it remain, full and purging at
the bung-hole, about two weeks. Lastly, to every nine
gallons put one quart of good brandy, and bung down.
If it does not soon drop fine, a steeping of isinglass may
be introduced, and stirred into the liquid, in the propor-
tion of about half an ounce to nine gallons.

N. B.

ON FAMILY WINE MAKING. , 355

N. B. Gooseberries, especially the largest, rich flavoured, Gooseberries
may be used in the mixture to great advantage; but it has may bea<ided-
been found the best way to prepare them separately, by
more powerful bruising, Or pounding, so as to form the
proper consistence in pulp; and by putting six quarts of
fruit to one gallon of water, pouring on the water at twice,
the smaller quantity at night, and the larger the next
morning. — This process, finished as aforesaid, will make
excellent wine, unmixed ; but this fluid, added to the former
mixture, will sometimes improve the compound.

ANNOTATION.

I am inclined to think the addition of brandy, here re- Brandy perhaps
commended, injurious : an opinion founded on the authority otter onu
of a respected friend, formerly a chemist in a country
town, who excelled in making family wine, and confirmed
by my own experience. A similar sentiment is entertained
by Dr. Anderson, as appears in his judicious letter on the
subject to the author of the preceding article, inserted in
Vol. X of the Bath Society's papers, which I shall here
annex.

I will only add, that the best home made wine I recollect Method of
to have tasted was made by expressing the juice of white currant wine.
currants, bruised but not picked from the stalks : adding
water to the fruit after it was pressed, in the proportion of
double the quantity of juice: mixing the two liquors to-
gether, and putting the whole into a barrel with three
pounds of pretty coarse brown sugar to every gallon of
the mixture : stirring it well, amLthen leaving it to ferment
with the bunghole at first open, and afterward loosely
covered, the barrel not being quite filled. As the sugar
does not immediately dissolve, the stirring must be repeated
occasionally at intervals of a few days, till this is effected.
After it has fermented properly, the barrel must be stopped
close ; and it may afterward be bottled for use. Some use-
ful information respecting the fermentation and manage-
ment of wine may be obtained from Mr. German's paper
on the wines of Champagne; Philos. Journal, Vol. XVII,
p. 353.

2 A 2 hleworthy

356

ON FAMILY WINE MAKING.

On r own fruits
afford wine as
food as foreign,

Liable to fail.

Two leading
points*

Quality of the
fruit.

klczcorth, Jan. 24, 1804.
Dear Sir,

" I received your letter some days ago re-
specting the wines that may be made from the natural fruits
of this country, which I should have sooner answered,
could I communicate any thing of the importance I wished;
but that not being the case, I felt a great reluctance at the
thought of troubling you with any tiling not satisfactory.

li I can say little else than that from our own expe-
rience for a short time past, and what I have seen of others,
I am perfectly satisfied that wine may be made from our
native fruits — red and white currants, gooseberries, black
currants, rasbenies, and other fruits, (with the help of
sugar) as good, and of as rich a flavour in all respects, as
any that are imported from abroad. But the particulars
in the process that may vary the qualities of the wine,
where the materials are the same, are so numerous, and
the time that must elapse before the result of any experi-
ment can be known is so great, that I despair of living to
see any certainty established on this head. At present I
sometimes taste as good wine of that sort as could be de-
sired, and again as bad as can be thought of, made by tha
same persons, when they can assign no reason for the dif-
ference. From our own limited practice I have been able
to ascertain only two points, that I think can be relied
upon as tolerably well etablished. These are, first, that
age, I mean not less than three years, is required to elapse,
before any wine, that is to be really good, can attain such
excellence as to deserve the name of good; and second,
that it never can attain that perfection, if spirits of any
kind be mixed with it. I apprehend that most of our made
wines are greatly hurt by not adverting to these two cir-
cumstances.

" Another circumstance that is in my opinion very
necessary for the formation of good wine of this sort, is a
certain degree of acidity in the fruit, without which the
wine never acquires the zest which constitutes its peculiar
excellence^ but hurries forward too rapidly into the state
of vinegar. Currants at all times possess enough of that
acidity ; but if gooseberries be too ripe they are apt to

want

ON PAMILT WINTE MAKING. 357

want it, and become insipidly sweet at an early period, Acidity of
though they soon become vinegar. It ought to be re- vj"iegar
marked, that the native acidity of the fruit is different from
the acidity of vinegar, and possesses qualities extremely
dissimilar. The sourness of vinegar, when it has once
begun to be formed, continues to augment with age; but
the native vegetable acid, when combined with saccharin*
matter, is gradually diminished as the fermentation pro-
ceeds, till it is totally lost in the vinous zest into which botn
this and the sugar are completely converted before any
vinegar is produced: if the fermentation be properly con*
ducted.

" This I believe is a new opinion, which experience
alone enabled me to adopt not very long ago. But I have
had so many experimental proofs of this fact, independent
of the support it derives from reasoning, that I am satisfied
it is well founded. I am satisfied farther, that the wines
of this country are debased chiefly by not adverting to it,
and of which I think you will be convinced also by a mode-
rate degree of attention.

M Every person knows, that an insipid sweetness is the The sweetness
prevailing taste in liquors when they begin to ferment, and gU wol,id the
that it is gradually changed into a pungent vinosity as the acidity,
process proceeds ; but few persons have had occasion to
remark, that the native acid of fruit undergoes a similar
change by the fermentatory process. Every one who tastes
made wines, however, soon after the process has commenced,
perceives that sour to a certain degree is mixed with the
sweet. It chances, indeed, that the sweet is sooner blend-
ed than the sour; so that when the liquor is tasted a few
months after it has been made, it hath lost some part of its
sweetness ; but still retains nearly the whole of the sour-
ness of the native acid of the fruit. And as the vinous
flavour is yet but weak, the liquor appears to be thin and
weak, and running into acidity. It is therefore feared, Common
that if it be not then drunk, it will soon run to the state of nusUke-
vinegar; on this account it is often used in this state, when
it forms a very insipid beverage. Frequently also, with a
view to check the acetous process, and to give that degree
of strength which will entitle it to the name of a cordial

liquor,

358 #N FAMTLY WTtfE MAKING.

Brandy, liquor, a certain portion of brandy is added to it, after

•ffedt°US ^ ^ which lt may be **B* for sonie time* The effect of this
addition is to put a stop to that salutary process of fermen-
tation which was going slowly forward, and gradually ma-
turing the native vegetable acid into vinous liquor, which
being at last blended with the saccharine vinous juice, pro-
duces that warm exhilarating fluid which cheers the heart,
and invigorates the strength of man. In this way the sharp
insipid and poor liquor which was first tasted is, by a slow
process, which requires a great length of time to complete
it, converted into rich pleasant wine, possessing, in a
great degree, that high zest which constitutes its principal
excellence.

ic My experience does not yet enable me to speak with
certainty respecting all the circumstances that may affect
the flavour, or augment or diminish the strength of wine,
or accelerate or retard the time of its ripening. But my
The flavour opinion at present is, that a great part of the flavour of
affected by the wine depends considerably upon the skin of the fruity
fruit. which may be augmented or diminished by the degree of

pressure the fruit is subjected to, and other particulars con-
nected with it; or by the macerating the fruit more or less
in the juice before the skins be separated from the pulp :
and that the ultimate qualities of the wine are considerably
affected by the proportion of the original native acid of the
fruit, conjoined with the saccharine part of the juice. It
seems to me very evident also, that the saccharine juice can
be more quickly brought into the state of wine than the
Some sooner fit acid portion of it, and that of course those wines that con-
fer drinking sjst entirely of saccharine matter, flavoured only by some
pleasing vegetable perfume, such as cowslip or elder-flower
wine, and others of similar sorts, may be sooner brought
to be tit for drinking than those in which the juices of fruit
form a considerable ingredient ; and may be also made of a
weaker and lighter quality. And that fruit-wines, in pro-
portion to the diminution of the quantity of fruit to that
of sugar, or in proportion to the quantity of acid in the
fruit, may be accelerated or retarded in the progress of fer-,
mentation ; but that strong full-bodied wine, of good fla-
V pur, must have a considerable proportion of native acid,

an4

ON FAMILY WINE MAKING. 339

and requires to be kept a long while before it can attain its
ultimate perfection.

u I have had too little experience in the practice of Grape wint^
making grape wine to enable me to speak with precision.
The flavour of different kinds of grapes we know varies
consid .<ibJy, which must affect the wine; but other cir-
cumstances in the process must affect it greatly. It is the
only fruit known in this country that affords juice in abun-
dance sufficient to admit of being made into wine without
the addition of water, or rich enough without the use of sugar.
Two years ago the season was so favourable, that my grapes
(the muscadine) ripened completely, and I determined to
try to make some wine of them without either sugar or
water. The juice was squeezed out by hand without any
pressure, as I had no press. It fermented very well, and
after a proper time it was tried. The liquor tasted sweetish,
but wanted much of the vinous zest we wished for. This
arose, I have no doubt, from the want of a due proportion
of native acid, which would have been probably supplied
by a complete pressure of the must, had I possessed the
means of doing it, especially if the bunches of grapes had
not been separated from the small foot-stalks to which
the berries adhere. But not having a quantity sufficient to
make it worth while to have a press, I thought of another
method of attaining the end I aimed at, to which I was Birds and ver-

forced to resort: on finding that birds and vermin arennnfondof

-, - t i grapes.

so greedy of the grape, that it is a matter next to impossi-
ble to preserve them for any time here in quantities after and frequently

they are ripe without being broken, which, by letting theoccasioua

. . n , , i i . . i , nmstv taste by

juice ilow out, lodges between the berries in the clusters, opening them.

and there becomes mouldy, and communicates a musty
taste that cannot be got rid of.

" To avoid all these evils, I determined to gather the fruit Attempt to
when it is so far ripened only as just to begin to be pecked remedy this.
by the birds. As the juice possesses at that time more ve-
getable acidity, and less of the saccharine taste than when
fully ripe, I conceive that the wine made from it will be
sharper, and have a higher zest than the other ; but dread-
ing that the juice might not be sufficiently matured to do by
itself, I added a portion of sugar and water to the juice,

and

3(30 ON FAMILY WINE MAKING.

and have put it by for trial. It fermented well, and the
liquor has at present as promising an appearance as f could
-wish. Should this mode of making grape wine succeed,
it will be by far the cheapest wine we can make in this
country ; for the quantity of juice yielded by the grape is
jfo much more abundant, aud so much richer than that of
our other fruits, and it is so much easier to be gathered
and otherwise managed, that it must be much more desira-
A d vantages of ble. The quantity of fruit produced too is much greater
the grape. wnen the vines are properly managed, than can be gotten

from the same extent of ground of other fruits, as to give it a
decided preference on the whole. I have just now in my
cellar above forty gallons of that wine made from the grapes
that were gathered from a wall of about fifteen yards in
length, and fifteen feet high. Nor was that crop above the
average. Neither had that wine above half the quantity of
sugar that other fruit wines would have required. I have no
doubt that were vines raised from seeds of the best and earliest
sorts, and carefully selected when they come to bear, we
might thus obtain a grape that would ripen very well in this
country without the assistance of a wall. It is by no means
improbable that such a vine was once known in England.
Black currant " Next to the vine, I agree with you in thinking that the
ranks next. black currant is the best fruit we have of that kind for ma-
king vt inc. I have seen some of it that was truly excellent.
It would be of great use for giving flavour to some other
wines.

« When I began this letter I thought that I had nothing
to say ; but being once begun, it has run on to an enormous
length. I hope you will forgive me for it. I now speak
little, and write less : and it requires an effort for me to be-
gin with either; but, like a disorderly clock, when I am
once fairly set agoing, I run on perhaps without rhiine or rea-
son. Wishing you success in all your useful pursuits.

U I remain, dear Sir,

*< Your most humble servant,

" JAMES ANDERSON."

VII, Description

MINERAL BASON IN WALES. 3gJ

VII.

Description of the Mineral Bason in the Counties of Mon-
mouth, Glamorgan, Brecon, Carmarthen, andJPembrokc.
By Mr. Edward Martin. Communicated by the Right
Hon. C. F. Grenville, F. R. S*

1 i HE irregular oval line, delineated on the annexed Limestone ba-
map (Plate IX.) shows nearly the inner edge of a little- ^IfjJw^Srmof
stone bason, in which all the strata of coal and iron ore«>aland iron
(commonly called iron stone) in South Wales are deposited; \Vales
the length of this bason is upwards of 100 miles, and the
average breadth in the counties of Monmouth, Glamorgan,
Carmarthen, and part of Brecon, is from 18 to 20 miles,
and in Pembrokeshire only from 3 to 5 miles.

2. On the north side of a line, that may be drawn in an On the north
east and west direction, ranging nearly through the middle °he stn^ti^e
of this bason, all the strata rise gradually northward ; and to the north,
on the south side of this line they rise southward, till they loutjl t0 the
come to the surface, except at the east end, which is in the south,
vicinity of Pontipool, where they rise eastward.

3. The depths from the surface to the various strata of Depths from
coal and iron ore depend upon their respective local situa- vary<
tions.

4. The deepest part of the bason is between Neath, in Deepest part
Glamorganshire, and Llanelly, in Carmarthenshire; tneu ^etmott"
uppermost stratum of coal here does not extend a mile in stratum.

a north and south direction, and not many miles in an east
and west direction, and its utmost depth is not above 50 or
CO fathoms.

5. The next stratum of coal, and those likewise beneath Second and
it, lie deeper and expand still longer and wider, and the iower strata.
lowest which are attended by parallel strata of iron ore,

of which there are in some situations about 16 accompanied
by irregular balls or lumps of iron ore, tfecupy the whole
space between Llanmaddock Hill, near the entrance of
Burry river, to Llanbidie, from the Mumbles to Cribbath,
from Newton Down to Penderryn, from Castle Coch to
Castle Morlais, and from Risca to Llangattock, and in

* From the Philos. Trans, for 1806, p. 342.

length

362 . MINERAL DASOiV IN WALES.

length on the south side of the bason from Pontypoo!
through Risca, Tinkwood, Llantrissent, Margam, Swansea
Bay, and Cline -Wood, to Llanmaddock Hill, and on the
north side through Biarnafon, Ebbw, Sirhowy, Merthyr,
. , Aberdare, Aberpergwm, Glyntowy, Llandibie, and the
Groat Mountain, to Pcmbrey Hill, near Llanelly in Car-
marthenshire, and their depths are at the centre range of
strata from G to 7G0 fathoms.
Strata running 6. The strata of coal and iron ore running from Pern-
m™then bay' ^7 HilI> tnrouSh Carmarthen Bay and Pembrokeshire to
and Pembroke- St. Bride's Bay, are only a continuation of those in the
shir*. counties of Glamorgan and Carmarthen, which lie next to

and parallel with the north side of the bason, all the re*
maining strata rising southward ; and the middle ranges on
the north side of the bason, are lost between where they
meet the sea near Llanmaddock Hill and the south side of
Pembrey Hill, iu their course towards Pembrokeshire, in
consequence of a contraction of the sides of the mineral
bason, or rather by its becoming shallower ; for in Pem-
brokeshire none of the strata of coal or iron ore lie above
80 or 100 fathoms deep, consequently all those which do
not lie above 5 or 600 fathoms in Glamorganshire and Car-
marthenshire have not reached this county, by reason of
the bason not being of sufficient depth and width to hold
them.
Strata at the 7. The strata of coal at the east end of the bason run,

east end of the ning from pontyp0ol to Rlaenafon and Clydach, and on the
north side from thence to Nanty Glo, Ebbw, Beaufort,
Sirhowy, Tredegar, Romney, Dowlais, Penderryn, Ply-
mouth, Cyfarthfa, Abernant, Aberdare and Hurwain Fur-
naces and Iron Works, are of- a cokeing quality, and
thence the whole strata of coal to St. Bride's Bay alter
in their quality to what is called stone coal, (the large of
which has hitherto been used for the purposes of drying
malt and hops, and the small, which is called culm, for
burning of limestone); the several strata of coal from Pon-
typool, on the south side of the bason, through Risca
Llan dissent, Margam, and Cline Wood, to Burry River,
Llantlly, and the south side of Pembrey Hill, are prin-

cipally of a bitumiuous or binding quality.

8. Notwithstanding

MINERAL BAS0V IN WALES. 3fig

•'8* Notwithstanding the principal strata of coal in Gla- Strata worked
morganshirc lie from 5 fathoms to 6 or 700 fathoms deep, f&£fa£^
still it has not been necessary to pursue these strata deeper
than about 80 fathoms.

9. The veins of coal and iron ore, in the vicinity of Method of
most of the iron works in Monmouthshire and Glamorgan- wor n*'
shire, are drained and worked by levels or horizontal drifts,

for which opportunity is given by the deep valleys which ge-
nerally run in a north and south direction, intersecting the
range of coal and iron ore, which run in an east and west
direction, under the high mountains, and thereby serving
as main drains, so that the collier or miner here gets at the
treasures of the earth, without going to the expense and
labour of sinking deep pits, and erecting powerful fire-
engines. However, in process of time, in situations where
the coal and iron ore that are above the level of these na-
tural drains become exhausted, it will be found necessary
to sink shallow pits, and erect fire-engines for the draining
and working of the coal and 'iron ore, and at a future
period, pits of greater depths must be sunk for the same
purposes.

10. There are 12 veins or strata of coal in this mineral Number and
depository, from '3 to 9 feet thick each ; which together ^Jjj*1** of
make 70f feet: and there are 11 more, from 18 inches to

3 feet, which make 24| feet, making in all 95 feet ; beside
a number of smaller veins from 12 to 18 inches, and from
6 to 12 inches in thickness, not calculated upon.

11. By taking the average length and breadth of the Produce in the
foregoing different strata of coal, the amount is about 1000 ™™i™°nwayof
square miles, containing 95 feet of coal in 23 distinct

strata, which will produce in the common way of work-
ing 100,000 tons per acre, 64,000,000 tons per square
mile.

12. If the whole extent of this mineral country was an Edges of the
even plain, the border or outbreak of each stratum would straU disturbed*
appear regular and true ; but owing to the interposition of

hills and valleys, the edges of the strata, if nicely measured
and planned, would seem indented and uneven, yet in many
instances the due range is totally thrown out of course,
in consequence of knots, dikes, or faults.

13. These

304 W7VERAL BA90X IS WALES.

The irregulari- £$. Th cse faults or irregularities arc not confined to the

hiTolhe^in' cdgcs of th* strata> b,,t they take Srantl ranges, through
the interior of the bason, generally in a north and south
direction, and often throw the whole of the strata, for
hundreds of acres together, 40, 60, 80, or 100 fathoms,
up or down, and still there is seldom any superficial ap,
pearance, that indicates a disjunction, for the largest faults
frequently lie under even surfaces.
It is not proba- 14. As every stratum rises regularly from its base to the
vdno^stratum SUI*ace? ai1(* is frequently visible and bare, in precipices
remains undis- and deep dingles, and often discovered where the earth or
severed. sojl js shallow in trenching, or in forming high roads, and

by reason of the whole of the country within this boundary
being so perforated by pits, and so intersected by the various
operations of art and nature, it is not probable that any
vein of coal, iron ore, or other stratum remains undiscover-
ed in this mineral bason.
Their distribu- 15. Glamorganshire engrosses far the greatest portion of
countes°.ng thC coal and iron orc> Monmouthshire the next in point of
quantity, Carmarthenshire the next, Pembrokeshire the
next, and Brecknockshire possesses the least.
Breakings out 16. The strata of coal and iron ore in *he last named
Brecknock-* "* county> whicn arc the lowest in the bason, break out
shire. northward, and only take place in the three following

distinct spots, viz. 1st. From Turch River (which is the
boundary between Lord Cawdor and Charles Morgan Esq.)
across the river Tawc and the Drin Mountain to the great
forest of Brecon. 2d. A corner of ground from Blacn
Romney to the north of Brynoer. 3d. Another spot,
from Rhyd Ebbw and Beaufort Iron Works, through
Llwyn y Pwll, near Tavern Maed Sur, to where it joins
Lord Abergavenny's mineral property.
Principal 17. Note. A principal fault is observable at Cribbath,

fault*. where the beds or strata of the limestone stand erect,

another, of considerable magnitude, lies between Ystrad-
vellte and Pendcrryn, where all the strata on the north side
of the bason are moved many hundreds of yards southward
(as at Dinas).
Limestone. 18. Note. The limestone appears to the surface all along

the boundary line in the counties of Monmouth, Glamorgan,

Carmarthen
4

MINERAL BASON IN WALTS. S(>5

Carmarthen, Brecon, and no doubt can be entertained of
its due range from Newton across Swansea Bay to the
Mumbles, and from Llanmaddock Hill across Carmarthen
Bay to Tenby. In Pembrokeshire it appears to the surface
on the south side of the bason, at Tenby, Ivy Tower, Co-
chelard, Bit Church, Williamston, Lawrinny, Cord, Canta,
and Johnston ; and on the north side of the bason, at Tern-
pleton, Picton, Harriston, and Persfield; yet it certainly
forms an underground connection from point to point.

The following is an Enumeration of the Strata, as tfiey
appear in the Section, at the Fool of Plate IX.

1. If foot Cwm little vein. Knumeration,

2. %l feet Hendro Vawr vein. of the strata

3. Three or four small veins of coal.

4. 3 feet the yard vein of Cwm.

5. If Do. the little coal vein.

2 or 3 courses of regular balls are seen between 5 and 6..
C. 4 feet Cwm Canaid coal.

Between 6 and 7 are balls not yet worked.

7. 4 feet, Clynderris coal.

The division between 7 and 8 varies much in the per-
pendicular distance between the veins sometimes 30 and
sometimes 20 yards.

8. 4 feet, the clay vein. \

9. 9 feet, Cwm Glo big vein.

Balls and little veins of mine arc seen in the division be-
tween 9 and 10.

10. 9 feet, Cwm Whern big vein.

11. 2 feet, Cwm Glo little vein and \\ foot little Tein with
\ yard of rubbish between them.

2 or 3 poor little veins of mine occur between 11 and 12.

12. 1 foot vein above the balls.

2 courses of balls, but no veins, between 12 and 13.

13. 4 feet, Whern vein, a little rubbish in the middle.
There are mines in the division between 13 and 14 ; but
not yet worked.

14. 2| feet, and 3 feet vein. These appear at Penywaia
with 1 foot rubbish between them.

16. 3 feet

366 MINERAL BASON IN WALES.

Enumeration IB. 3 Ceet, Dowlais little vein, at Penywain.

•f the strata. ]\j0 mine yet found in the division between 15 and 1G.

16. 4 feet vein between Cwm Mpin and Penywain.

No mine of consequence occurs between. 16 and 17.

17. 3 feet Cwm Moin vein. Between 17 and 18 the fol-
lowing occur in succession as here set down.

3 inches yellow vein.

3 ditto Pin Brith.

4 ditto the black vein.
4 ditto the yellow vein.

4 ditto the jack vein.

2 ditto the Gurthean vein.

5 ditto the Gurthean Clase Vawr.

5 ditto the Gurthean Clase, or blue vein.

1 ditto upper black pin.

2 ditto lower black piu.
4 ditto the big vein.

3 ditto Gurthean Spinkin.

4 ditto Gurthean Vawr gona.

2 ditto Gurthean Knappe.

3 ditto Piu Garw.

IS. Smoot and fire clay. Between 18 and 19 are
4| inches lower black vein.

4 ditto black balls.

1 ditto upper inch vein.

1 ditto lower inch vein.

2 ditto upper 2 inch vein and 2 inches lower 2 inch vein.

2 ditto irregular balls.

3 ditto best pin.

19. Course of very hard rock, 3 feet.

VII. On

ON FAIRY RINGS. 367

VIII.

On Fairy-Rings. By W. H. Wollaston5 M. D. Sec R. £.*

1 HE circles of dark-green grass frequently observed in Various aft.
old pastures, and known to most persons by the name °f COunt for fairy
Fairy-rings, although in themselves of no importance, yet rings,
seem to claim some attention, if we consider the many in-
genious attempts that have been made to explain their
origin. On such a subject I shall be excused offering any
examination of opinions previously formed by others, and
shall therefore proceed briefly to relate such observations as
I made, during a few years residence in the country, on
the progressive changes of these circles, and which seem to
me to lead to a clear and satisfactory conclusion.

That which first attracted my notice, was the position of Certain fungi
certain fungi which are always Lo be found growing uPOn^°^ ut
these circles, if examined in a proper season. In the case
of mushrooms, I found them to be solely at the exterior
margin of the dark ring of grass. The breadth of the ring
in that instance, measured from them toward the centre,
was about twelve or fourteen inches, while the mushrooms
themselves covered an exterior ring about four or five inches
broad.

The position of these mushrooms led me to conjecture These occasion

that progressive increase, from a central point, was thethe nn§ b7

_ , _ . . , , *" ' . . T ' spreading pro-

probable mode of formation of the ring. 1 was the more gressively front

inclined to this hypothesis, when I found that a second the centre> as

- r i . .i . , tneY cannot

species of fungus presented a similar arrangement, with re- continue to

spect to the relative position ef the ring and fungi; for 1 §row in the
■ . • ... , same spot.

observed, that in all instances the present appearance of

fungi was upon the exterior border of a dark ring of grass.

I thought it not improbable that the soil, which had once

contributed to the support of fungi, might be so exhausted

of some peculiar pabulum necessary for their production,

as to be rendered incapable of producing a second crop of

that singular class of vegetables. The second year's crop

would consequently appear in a small ring surrounding the

original centre of vegetation, aud at every succeeding year

* Phil. Trans, for, 1807, p. 133.

the

368 ON FAIRY RIKGJ.

the defect of nutriment on ona side would necessarfly cause
the new roots to extend themselves solely in the opposite
direction, and would occasion the circle of fungi conti-
nually to proceed by annual enlargement from the centre
outwards. An appearance of luxuriance of the grass
would follow as a natural consequence, as the soil of an
interior circle would always be enriched by the decayed roots
of fungi of the preceding year's growth.
Dr. Hutton's By reference to Dr. Button's* u Observations on cer-

them at Ar- *a*n natural appearances of the ground of the hill of Ar-
thur's seat. thur's Seat near Edinburgh," we find the progressive en-
largement distinctly noticed ; but as he happened not to
observe any of the fungi that occasioned them, he speaks of
it merely as " a piece of natural history worth recording,
and for which, a theory is wanting."

Respecting the enlargement, he says, Ci from all the ob-
servations I have made, this progress seems always to have
proceeded in the direction of a line bisecting the segment,
that is to say, those portions of concentric circles are
never inscribed, but always circumscribed; and for this
reason it appears, that those circles of which segments are
.exhibited to our observation must be increasing and not di-
minishing in their diameters."
Br. Withering Although Dr. Hutton has overlooked the real origin of
ascribed them g^ appearanccS9 J)r. Withering has ascribed them to their
cause. true cause; but his remarks are confined to one species of

agaric (the ag. orcades of his Arrangement), and do not ap-
pear to have been confirmed by any subsequent observation
of their annual progress.

a I am satisfied," says he, cc that the bare and brown,
or highly clothed and verdant circles in pasture fields called
Fairy-rings are caused by the growth of this agaric."
11 Where the ring is brown and almost bare, by digging up
tin: soil to the depth of about two inches, the spawn of the
fungus will be found of a grayish white colour ; but where
the grass has again grown green and rank, I have never
-found any of the spawn existing."

* Edinburgh Transactions.

Had

,G\- TAIKY RINGS. .^{J9

r Had Df. Withering frequently repeated this examination Spawn of fungi
of the soil he would have corrected the last remark, which found' mXr
is not universally true, as the grass may at some period be the luxuriant
found luxuriant even over the undecayed spawn. During grass*
the growth of the fungi, they so entirely absorb all nutri-
ment from the soil beneath, that the herbage is for a while
destroyed, and a ring appears bare of grass surrounding
the dark ring. If a transverse section be made of the soil
beneath the ring at this time, the part beneath the fungi
appears paler than the soil on either side of it, but that
which is beneath the interior circle of dark grass is found
on the contrary, to be considerably darker than the ge-
neral surrounding soil. But in the course of a few weeks
after the fungi have ceased to appear, the soil where they
stood grows darker, and the grass soon vegetates again
with peculiar vigour; so that I have seen the surface co-
vered with dark grass, although the darkened soil has n«t -
exceeded half an inch in thickness, while that beneath has .

continued white with spawn for about two inches in depth.

The section of the space occupied by the white spawn has Progressive.
in general nearly the same form, and may be compared to course of the
that of a wave proceeding from the centre outwards, as. its
boundary on the inner side ascends obliquely toward the
surface, while its exterior termination is nearly in a ver-
tical position. The extent occupied by the spawn varies
considerably according to the season of the year, being
greatest after the fungi have come to perfection, and is re-
duced to its smallest dimensions, and may in some cases
not be discernible, before the next year's crop begins to make
its appearance.

For the purpose of observing the progress of various Annua! in-

circles I marked them three or four years in succession, bycrea,se ° -

J i J circle various.

incisions of different forms, by which I could distinguish

clearly the successive annual increase, and -I found it to

vary in different circles from eight inches to as much as two

feet. The broadest rings that I have seen were those of Br°adest when
., , " \ . . from the com-

the common mushroom (ag. campestris); the narrowest mon mush-

are the most frequent, and are those of the champignon roo,n : "ar" ,

J* ' r ■ rowest from th ".

(ag. oreades of Dr. Withering). Ihe mushroom accord- champignon.

iugly makes circles of largest diameter, but those of the

\ ol, XIX. — Supplement. B b champignon

370 0N FAIRY AlMfCl.

Three other champignon are most regular. There are, however", a»

thT^e^ffect marty as *hrec other fungi that exhibit the same mode of
extension, and produce the same effect upon the herbage.
These are the ag. terreus, ag. procerus, and the lycopcrdon
bovfstti) the last of which is far more common than the two
last mentioned agarics.

Confirmation of There is one circumstance that may frequently be ob-
served respecting these circles, which can satisfactorily be
accounted for, according to the preceding hypothesis of
the cause of their increase, and may be considered as a con-
firmation of its truth. Whenever two adjacent circles are
found to interfere, they not only do not cross each other,
but both circles are invariably obliterated between the
points of contact : at least in more than twenty cases, I
have seen no one instance to the contrary. The exhaustion
occasioned by each obstructs the progress of the other, and
both are starved.

EKffeient fungi I think it also not unworthy of observation, that dif-

stop the pro- ferent species of fungi appear to require the same nutri-
Ijress of each l - . - ^ . . ~

«ther~ ment; for in a case of interference between one circle of

puff-balls and another of mushrooms, they did not in-
tersect; but I cannot say positively that I have seen more
than one instance.

I once found that a tree had interrupted the regular pro-

Circ»€ inter-

rupted by i gress of a circle ; but this appeared to be only a temporary

tree,

impediment, as the extension had proceeded at the usual
rate, and by passing obliquely from each side into the soil
beyond the tree, had given the ring the form of a kidney,
so that another year or two would probably reunite the two
extremities into one curve surrounding the tree.
Ii>s-awn will Being desirous of ascertaining in what length of time a
xiot vegetate goii might again recover the power of producing a fresh

ipo^foTsome cr0P of fung*!? I cut a groove? in one or two instances,
time. along the diameter of a mushroom-ring, and inserted a

quantity of spawn taken from its circumference, with the
hope of seeing it vegetate for some distance near the centre ;
but the experiment failed altogether : and as I shortly after
quitted my residence in the country, I had no opportunity
of repeating the experiment, and must leave it to be pro-
secuted by those who are more favourably circumstanced.
** IX. Account

NEW MtsiCAL I.VStRtMtHt, 371

IX.

Account of a Musical Instrument, called an Organized
Lyre, invented by Mr. Adolphus Ledhuy, late Geo-
metrical Surveyor of Forests, of Coucy-le -Chateau, itf
the Department of the Ahne *♦

1 HE object of the author was simply to improve the Organized lyr*.
guitar-lyre, but by a simple mechanism be has rendered the
sounds of this new instrument susceptible of several dif- Capable of imi-
ferent tones or stops, by means of" which tbe performer jnst"umenu!
may imitate several instruments, such as the lyre, tbe piano
forte, the barp, &c. ; while at tbe same time it is as easy
to play upon as the guitar-lyre, being fingered in the same
manner, and riot more inconvenient for carriage. In ac-
companiments, soloes, and quartettoes, or with several
Other instruments, it answers equally well: and, when it
was submitted to the examination of the first artists in
Paris, the inventor received the most flattering enco-
miums.

Mr. Adolphus has likewise composed instructions for his
new lyre, in which he details every particular necessary for
learning to play on it without a master : and in a second
part he has added examples And lessons of every kind, to
point out the advantages derivable from his invention in
gradations of tone and expression ; so that any one, who
plays already on the guitar, or lyre-guitar, may render
himself familiarly acquainted with this instrument in Jess
than a month.

The following is a description of the instrument. Description cf

1. The organized lyre has fifteen strings, separated into the instrum*nt'
three distinct divisions, and embracing the compass of four in faee ^m?*
complete octaves. The three divisions are called the base, sionj.
tenor, and treble.

2. It has a row of six keys, which include the extent of Keys,
■three octaves. With these the pianoforte may be imitated,

but the sounds produced are more soft.

* Sonninis Bibliotheque Pbysico-e'conornique, July, 1807, p. 01.
The inventor has taken out a patent for this instrument in France.
B b 2 3. By

372

Mute.

Mode of ap-
plying th«
mute.

Two necks for
Angering.

Case.

EAST INDIA BUTTER TREE*.

3. By means of a mote the performer may change the
sound of the instrument, either gradually or instanta-
neously, from the loudest of which it is capable to the
softest, or the contrary.

To apply this mute the performer has not the least oc-
casion to employ his hand, or stop his performance : all
that is required is to press with his arm on a pedal, which is
precisely at the place where the arm rests habitually on the
instrument, and to increase or diminish this pressure, till
the mute produces the desired effect.

4. The instrument has two necks, each wrth six strings,
which are fingered in the same manner as the guitar-lyre.

5. The case of the instrument, which is indispensably-
necessary for its conveyance from place to place, is equally
so for playing on it ; because, the performer being obliged
to have the left knee raised a little, the better to support the
instrument, and to give freedom of movement to the arm,
he rests his foot on the box, out of which rises a stand for
the music, which may be raised or lowered at pleasure.
This stand folds up so as not to increase the size of the
case, and adds but little to its weight.

Generic cha-
racter.

Specific cha-
racter.

X.

A Botanical and Economical Account of Bassia Butyracea^
or the East India Butter Tree. By W. Roxburgh?
M.I>*

BASSIA BUTYRACEA.

Polyandria monogynia:

V^ALYX beneath, four or five leaved. Coral, one pe-
talled : border about eight cleft.- Berry superior, with,
from one to five seeds.

Bassia but yr ace a. Roxburgh.

Calyx five-leaved ; stamens thirty or forty, crowning the
subcylindric tube of the corol.

* From the Asiatic Researches, Vol. VIII.

Fulmah,

EAST INDIA BUTTER TREE.. £f<J

Fuizcak, phufaarahy or phulxara, of the in&abitants of Synonimes.
the Almorah hills, where the tree is indigenous. Flower-
ing time, in its native soil, the month of January ; seed*
ripe in August.

Trunk of the larger trees, straight, and about fire or Trunk... r _
six feet in circumference. Bark of the young branches
smooth, brown, and marked with small ash-coloured
specks.

Leaves alternate, about the ends of the branchlefs, pe- Leave*,
tioled, obovate-cuneate, obtuse-pointed, entire; smooth
above, villous underneath; veins simple, and parallel;
length, six to twelve inches ; breadth, three to six.

Petioles, from one to two inches long. Petioles.

. Stipules, if any, minute, and caducous. Stipule*

Flowers numerous, round the base of the young shoots, Flowers.
aud from the axils of the lower leaves, peduncled, large,
pale-yellow, drooping.

Calyx, four, five, or six leaved (five is by far the most Calyx,
common number) ; ovate, obtuse, covered externally with
ferruginous pubescence, permanent.

Corol; tube subcylindric, length of the calyx; border Corolla,
of eight, spreading, oblong, obtuse divisions, longer than
the tube.
' Stamens ; filaments from thirty to forty, about as long Stamens.
as the tube of the corol, and inserted on its mouth. An-
thers linear-oblong.

Pistil, germe conical, (ten or twelve celled, one seeded,) Pistil.1
tlowny, surrounded with a downy nectarial ring. Style
longer than the stamens ; stigma acute.

Berry oblong, generally pointed by a remaining portion Berry,
of the style; smooth, fleshy, containing one, two, or three,
rarely more, large seeds ; the rest not ripened.

Seeds oblong, rather round than flat, but differing in Seeds,
shape according to the number contained in each fruit;
smooth, shining, light brown, with a long, lanceolate,
lighter coloured, less smooth, umbilical mark on the in-
side.

This tree, which is rendered interesting on account of its
seeds, yielding a firm butyraceous substance, resembles ^s.e"J,.es bai"
4 bassidt

#4

tAST INDIA BtTTETl TREE.

bassia latifolia, (see Coromandel Plants, Volume I, No. !9;
also Asiatic Researches, Volume I, page 300.) so much as
scarce to be distinguished from it, except by the corol and
stamina.
T>ifer«nc€ in Here (in bassia butyracea) the corol is of a thin texture,
the corols, ^j^ a tu|je neaj.iy cylindric, and border of eight, large,
spreading, oblong segments. There (in bassia latifolia) it
is thick and fleshy, with a gibbous, indeed almost globular
tube; and border of generally more than eight, small,
cordate, rather incurved segments,
andstamioa. Here, the stamina, from thirty to forty in number, hare
long filaments inserted on the mouth of the tube of the
corol. There they are fewer in number ; have very short
filaments, and are arranged in two, or three series, com-
pletely within the tube, to which they are affixed.
Other sped ei. It may not be improper to notice here some other species
of the same genus. The following Botanical description of
bassia longifolia, Linn. Mant. page 563, I have been
favoured with by Doctor Klein, of Tranquebar, and the
account of its economical uses by the Reverend Doctor John
or' the same place.

Description by Doctor Klein,
Bassia Jongi- Calyx, Perianth ; monophyllum, 4-partitum ; laciniis

folia described, ovatis, acutis, coriaceis, extus tomento ferruginco obductis,
persistentibus.

Corolla monophylla, campanulata; tubo cylindraceo,
inflato, carnoso, limbo 8-partito; laciniis lanceolatis,
erectis.

Stamina, filamenta 16, brevissima, in, duos ordines divisa,
quorum octo ad incisuras laciniarum, octo in tubo corollat
inserta. Anthers lineares, sebaceae, acuta;, extus piiosa*,
limbo breyiores,

Pistil: Germen superum, ovatum. Stylus setaccus, co.
roll a duplo Iongjor. Stigma simplex.

Pericarp : drupa pblonga, J -3 sperma, carnosa, lactes-
cens. Seminibus subtrigonis oblongis.

Arbor magna; ramis sparsis, erectis, horizontalibusquc.
« Folia sparsa, petiolata, Ianceolata, acuta, integerrima,

glabra, venosa.

Florcs longe-pedunculafi, axillares, solitarii, etaggregati.

1st. The

EAST INDIA BUTTER TEEE. §*£&

1st. The oil, pressed from the ripe fruit, is used as a Oil used in
common lamp oil, by those who cannot afford to buy the l*raPV
oil of the cocoa-nut. It is thicker, burns longer, but dim*
mer, smokes a little, and gives some disagreeable smell.

2d. It is a principal ingredient in making the country for making
soap, and therefore often bears the same price with the soap>
oil of the cocoa-nut.

3. It is, to the common people, a substitute for ghee, in cookery,
*,nd cocoa-nut oil, in their curries and other dishes. They
make cakes of it, and many of the poor get their livelihood
by selling these sweet oil cakes.

4th. It is used to heal different eruptions, such as the and in medi-
itch, &c. cine-

5th. The cake (or sakcy) is used for washing the head ; The cake.
and is carried, as a petty article of trade, to those coun-
tries, where these trees are not found.

6th. The flowers, which fall in Mat/, are gathered by the Flowers eaten,
common people, dried in the sun, roasted, and eaten, as
good food. They are also bruised, and boiled to a jelly,
and made into small balls, which they sell or exchange, for
fish, rice, and various sorts of small grain.

7th. The ripe fruit, as well as the unripe, is eaten by the Fruit eaten,
poor, as other fruits. Of the unripe, the skin is taken off,
and after throwing away the unripe kernel, boiled to a jelly,
and eaten with salt and capsicum.

8tfe. The leaves are boiled with water, and given as a Leaves a medi-
medicine, in several diseases, both to men, and to cattle. '

9th. The milk of the green fruit, and of the tender bark and mu%
is also administered as a medicine.

10th. The bark is used as a remedy for the itch. and bark,

11th. The wood is as hard, and durable, as teak wood, Wood,
but not so easily wrought, nor is it procurable of such a
length for beams, and planks as the former; except in clay
ground, where the tree grows to a considerable height; but,
in such a soil, it produces fewer branches, and is less fruit-
ful, than in a sandy, or mixed soil, which is the best
juited for it. In a sandy soil, the branches shoot out nearer
to the ground, and to a greater circumference, and yield
more fruit. These trees require but little attention;
^eyond watering them during the first two or three years,
in the dry season. Being of so great use, we have here

wiiqle

of the same
genu

o7() $4$S INDIA BUTTER- TREfc.

whole groves of them, on high, and sandy grounds, where
no other fruit trees will grow.
Flowers eaten 12th. We may add, that the owls, squirrels, lizards,
by animals. dogs? and jackaj^ take a share of the flowers ; but the
vulgar belief is, that the latter, especially in the time of
blossom, are apt to grow mad, by too much feeding ow
them, x
Basi>ia obovata. Bassia obovata, Forster's Prod. No. 200 r a native of
the Isle of Tanna, in the South Sea. Of this species I
possess no other account than the definition, which cor-
responds with the habit of the genus. If Forster has left us
no account of the uses of the tree, it may be worth while
to make inquiry, when an opportunity offers.
Shea a species Park's shea, or butter tree of Africa, we have reason,
from his description, and figure, as well as from analogy,
to suppose a species of this same genus. At page 352 of
his travels in the interior of Africa he says, u The appear-
ance of the fruit evidently places the shea tree in the natural
order of sapotae, (to which bassia belongs,) and it has
some resemblance to the madhuca tree (bassia latifolia,)
described by Lieutenant Charles Hamilton, iu the Asiatic
Researches, Volume I, page 300.
Park's account " The people were every where employed in collecting
°f & the fruit of the shea trees, from which they prepare a

vegetable butter, mentioned in the former part of this
. work *. These trees grow in great abundance all over this
part of Bambarra. They are not planted by the natives, but
are found growing naturally in the woods; and in clearing
woodland for cultivation, every tree is cut down but the
: shea. The tree itself very much resembles, the American
oak ; and the fruit, from the kernel of which, first dried in
the sun, the butter is prepared, by boiling the kernel in

* This commodity, shea toulou, which, literally translated,
signifies tret-butter, is extracted, by means of boiling water, from
fKe kernel of the nut, has the consistence and appearance of butter,
and is in'truth an admirable substitute for it. It forms an impor-
tant article in the food of the natives, ahd serves also for every
domestic purpose in which oil would otherwise be used. The de-
lnaud for it is therefore great. Fork's rl ravels in Africa. Page 20'.

water

BAST INDIA BUTTER TREE* 377

iwatPr, has- somewhat the appearance of a Spanish olive.
The kernel is enveloped in a sweet pulp, under a thin green,
rind; and the butter produced from it, besides the advantage
of its keeping the whole year without salt, is whiter,
firmer, and to my palate, of a richer flavour, than the best
butter I ever tasted made of cows milk. The growth and
preparation of this commodity seems to be amongst th*
first objects of African industry, in this and the neighbouring
states; and it constitutes a main article of their inland
commerce." Park's Travels in Africa, page 203-8.

In the following account of the bassia butyracca, by Bassia Butyra-
Mr. Gott, we find the people of Almorah eat the dregs, cea*
left after the finer parts have been extracted ; consequently
there can be little doubt of the wholesomeness of the pure
•vegetable butter itself. The thick oil of bassia lafifolia,
and longifolia, the natives of various parts of India
either use alone, or mixed with ghee (clarified butter), in
their diet.

On captain Hardwicke's departure for England, in the Some given the
beginning of 1803, he gave me a small quantity of theauthor m1803-
above-mentioned substance, observing, that the only ac-
count he could give me of it was, that it was reported
to him to be a vegetable product from Almorah, or its
neighbourhood, where it is called fulrcah, or phulwarah.
In consequence of this information I applied to Mr. Gott,
(who is stationed in the vicinity of that country,) to make
the necessary enquiries ; and from him I procured an abun-
dance of well preserved specimens, at various times, in
leaf, flower, and fruit. From these, and that gentleman's
account of the tree, and its product, the foregoing descrip-
tion was taken.

The same sample, which I got from captain Hardwickc Keeps well,
in January, 1803, I have still by me. It remains perfectly
sweet, both in taste and smell. Its flavour is that of cloves;
having, I presume, been perfumed with that spice, previ-
ously to its falling into his hands, a practice mentioned ki
the following narrative. At this instant the thermometer is Consistent
at ninety-five, and for these six weeks, it has rarely been.
below ninety, and has ofteu risen to on^ hundred, or mora,
yet it continues about as firm as butter is in England during
winter,

Mr. Gott's

37S

tAST IMDIA TJUTTER TItfcF.

Account of
the tree.

Native count n

Nut

Mr. Gott's account of the tree, and its product, is at
follows t —

The tree producing a fat-like substance, known in this
country by the name of phulicah, is a native of the Almo-
rah hills, and known there by the same name. The tree i*
*earce, grows on a strong soil, on the declivities of the
southern aspects of the hills below Almorah, generally at-
taining the height, when full grown, of fifty feet, with a
circumference of six. The bark, of such specimens as I
have been able to obtain, is inclined to smoothness, and
speckled ; it flowers in January, and the seed is perfect
about August, at which time the natives collect them, for
the purpose of extracting the above substance. On opening
the shell of the seed or nut, which is of a fine chesnut co-
lour, smooth, and brittle, the kernel appears of the size
and shape of a blanched almond; the kernels are bruised,
Fat exprrsscd. on a smooth stone, to the consistency of cream, or of a
fine pulpy matter ; which is then put into a cloth bag,
with a moderate weight laid on, and left to stand, till the
oil, or fat, is expressed, which becomes immediately of the
consistency of hog's-lard, and is of a delicate white colour.
Its uses are in medicine; being highly esteemed in rheuma-»
tlsm, and contractions of the limbs. It is is also much
esteemed, and used by the natives of rank, as an unction,
for which purpose, it is generally mixed with an utr of
some kind. Except the fruit, which is not much esteemed,
no other part of the tree is used.

This tree is supposed to bear a strong affinity to the
mawa, (madhuca, or bassia latifolia;) but the oil or fat,
extracted from the seeds, difiers very materially. The oil
from the maica is of a greenish yellow colour, and seldom
congeals. That from the phulicah congeals immediately
after expression, is perfectly colourless; and, in the hottest
weather, if melted by art, will, on being left to cool, re-
sume its former consistency. The oil from the seed of the
mazca, if rubbed on woollen cloth, leaves as strong a stain
as other oils or animal fat. The fatty substance from the
phuhcah, if pure, being rubbed on woollen cloth, will
leave no trace behind.

Th<|

Use.

Its difference
from oil of
mavra.

EAST INDIA- BUTTER TREE. 379

The oil of marca is expressed in considerable, quantltlei
about Cazcnpoor, and Furruckabad, and being mixed
With, is sold as ghee,

This fatty substance very rarely comes pure from the hills,
and receives more and more adulteration, (by adding the
purest ghee,) as it passes down to the lower provinces : age
gives it the firmness of pure tallow.

Additional Remarks by the same, in consequence of a few
Queries transmitted to Mr. Gott.

It is supposed there might be annually procured from Farther re-
twenty to thirty maunds, at the price of fourteen or fifteen mar
rupees the maund.

1st. It is never taken inwardly as a medicine, nor is it
used in diet ; further than that the dregs, after the purer
fatty substance is expressed, are eaten, as a substitute for
ghee, by the peasants, or labourers, who extract the fat.

2d. I have some pure, which has been by me ten months,
and it has neither acquired colour, nor bad smell.

3d. After it is imported into Rohilkhund, it is scented
-with utr, (an essential oil,) and a little of the flour of In-
dian corn (zea mays) is added, to increase its consistency.
N. B. This flour is added on account of its peculiar
whiteness.

4th. If it is clean, and free from dirt, it never undergoes
any purification ; if the contrary, it is heated, and filtered
through a coarse cloth.

5th. The flowers are never used. The pulp of the fruit
is eaten by some ; it is of a sweet, and flat taste.

The timber is white, soft, and porous ; and is never Wood,
made any use of by the natives. It is nearly as light as the
$emul) or cotton tree (bombax hcptaphj/llum).

XI. Observations

S30

ANALYSTS O? POLISHING SLATf..

Where found.

Described.

Stratum
described.

XI.

Observations on Werner's Silex Sthistosus Politorius, •
Polterschiefer, from Biffin, in Bohemia *.

: A HIS substance, called polishing slate, is found about thrcQ
miles south of Billin, in Bohemia, immediately under the
vegetable mould, and less than a yard deep. It is of a yeU
lowish colour, and slaty texture ; has an earthy appearance. ;
and leaves a coloured mark on cloth. Between the fingers
it is easily reduced to a powder, which is a little rough to the
feel ; it adheres strongly to the tongue ; it is infufible. Its
specific gravity according to Mr. Habcrle is 0*6 ; and if left
twelve hours in water 100 parts absorb 117. In Saxony
it is known in the shops by the name of silver tripoli.

In the place where I observed it, near the top of a
pretty high hill, it forms the superior part of a stratum,
which increases in density as you penetrate into it; and in.
some places at the depth of two yards it is compact, with
a yellowish and somewhat shining aspect, like that of cer-
tain semiopals : but it is not so hard, or so heavy. From
every thing I observed on the spot, the polishing slate is
nothing more than a portion of this stratum, the texture of
which is loosened and altered by decomposition. Accord-
ing to Mr. Reuss, who lives at Billin, the stratum includes
remains of vegetables, and impressions of fish. Everything
besides indicates, that it is a recent alluvial production.

Mr. Bucholz has analysed both the polishing slate and
the adhesive slate, klebschiefer, that accompanies the meni-
lite of Menil-Montant, which had been considered as a va-
riety of it : and as Mr. Klaproth has made a more full and
complete analysis of the Klebschiefer than that he first gave
the public, we shall here present the three analyses in a com-
parative view.

Polishing slate

Adhesive

slate

by Bucholz.

by Bucholz.

by Klaproth.

Silex ... 79

.

-

- -

58 - -

- 62*5

Alumine - - 1

-

-

- -

5 - -

- 0-75

Lime - - - 1

.

-

- .

1-5

- 0-25

Oxide of Iron 4

-

-

.

9 - -

- 4

Water - - 14

.

.

- -

19 - .

- 22

Magnesia - - -
Carbon - -

6-5 -

- 8
. 0-75

99 99

* Journal des Mines, K. 121, p. 77.

98-25

SCIENTIFIC NEWS. gjU

The oxide in the analysis of the adhesive slate by. B.u- v

.cholz was part of iron, part of manganese: and in the
analysis by Klaproth the gas that escaped is included in the
•22 of water. He likewise found an alkali present, but in
too small quantity to be weighed.

SCIENTIFIC NEWS, .#<;.
Tabellarische Uebersicht tier chemisch einfachen iinrtzusamr
mcngesetzten Stojfe : &;c. A tabular. View of simple
and compound chemical Sub stances y with their Synonimes^
according to the ne:cest Discoveries: by Fred. S/ro-
meyer, M. D. and Prof, at Gottingcn. 32 whole Sheet
Tables. 1806.

P.

ROF. STROMEYEIi has here given a systematic ar- Stromeyefs
rangement of the different substances, that are the parti- chemical
cular objects of chemical science, with a pretty copious
collection of synonimes in German, Latin, French, and
-English, The only innovation he has allowed himself, ac-
cording to his preface, is the classing of oil, sugar, starch,
gluten, and several other vegetable and animal matters, as
oxides with compound, radicals, consisting either of carbon
and hidrogen, or carbon, hidrogen, and nitrogen. Among
these he makes wax differ from fixed oil only in being more
oxided; and adipocere from fat in the same manner. By
the b)', the only name he gives for adipocera in the English
column is fat-wax, a literal translation of the German
fettzcachs.

With these tables prof. S. sent me an account of a paper fnvestigati
he read to the Gottingen Society, Oct. 12, 1805, .con- the compounds
taining part of the results of his chemical investigation of withmefals.
the union of hidrogen with metals. On the present oc-
casion he confined himself to that of arsenic. This he ob- Best process
serves succeeds best by digesting an alloy of fifteen parts qf ft|. arsenicate^
tin and one of arsenic with concentrated muriatic acid in a
retort connected with the pneumatic apparatus. He was
led to this by the observation of Proust, that muriatic acid
completely frees tin from arsenic : and on this occasion he
convinced himself by experiments, that the fetid hidrogen

gas

382

SCIENTIFIC NEMl.

Mistake of
Fourcroy.

Partly reduced
to n liquid by
cold.

Its properties.

Effects on
feluod.

Action with
regents.

Absorbed by
water only
when contain-
ing air.

J. fleets t>f com-
bustion with'
different pro-

gas evolved, when the tin of the shops is dissolved in mu-
riatic acid, is not a compound of tin and hidrogen, as
Fourcroy conjectures in his Chemical System, Vol. VI,
p. 43, (English Ed.) but of arsenic and hidrogen. When
arsenicated hidrogen gas is formed in the manner directed
above, a very pure oximuriate of tin is obtained.

Though the arsenicated hidrogen gas retains its aeriform
state under every known degree of atmospheric tempera-
ture and pressure, prof. S. condensed it so far as to reduce
it in part to a liquid, by immersing it in a mixture of snow
and muriate of lime, in which several pounds of quicksilver
had been frozen in the course of a few minutes.

The smell of this gas, he says, is not alliaceous, as has
been said, though in the highest degree fetid and nau-
seating. Warm blooded animals, particularly birds, were
killed in a few minutes in an atmosphere containing one
tenth of this gas : but frogs and insects lived in it two or
three hours. Blood fresh drawn from a vein became black
after standing a few minutes in contact with it ; and in six
or eight hours a layer of reduced arsenic was visible on its
surface. The rise of the fluid in the jar likewise proved,
that absorption had taken place : but no such change ap-
peared in blood exposed to pure hidrogen gas. Neither
sirup of violets, infusion of litmus or turmeric, nor paper
stained with them, had its colour in the least altered by the
gas. Infusion of galls, and alkaline sulphurets or hidro-'
snlphurets, have no observable action on it. It is not ab-
sorbed by alkalis ; and scarcely in any perceptible degree
by distilled water, particularly if freed from air as much as
possible by long ebullition. If however the water contain
atmospheric air, or if the arsenicated hidrogen gas be
mixed with atmospheric air, not only absorption but de-
composition takes place, part of the hidrogen and of the
arsenic combining with oxigen so as to form water and
brown oxide of arsenic, and part appearing in the form of
pure hidrogen gas and metallic arsenic. Hence it is, that,
as Proust observed, ajar in which this gas is kept over
water will acquire a coating of arsenic and its oxide.

The arsenicated MdVogen gas burns in contact with at-
mospheric air, and a thin coat of arseuious acid and brown

oxide

SCIENTIFIC HEWS. 383

oxide of arsenic is deposited on the sides of the vessel, ff portions of

it be mixed with twice its volume of atmospheric air, the oxl8en-

product of the combustion is arsenious acid and water.

With six times its bulk of atmospheric air it will not take

fire. A mixture of it with an equal part of atmospheric

air cannot be fired by the electric spark. With an equal

bulk of oxigen gas it detonates violently, and the products

are water and arsenious acid: with only half, or a third,

of oxigen gas, oxide of arsenic likewise is formed, and

part of the metal is reduced. With five parts of oxigen

gas it burns without detonation. Arsenic acid is formed

in none of these processes. The combustion having been

tried with various proportions of the two gasses in VoItars

eudiometer, the mean of the experiments gave 0*72 of a 1 pait requires

cubic inch of oxigen gas as the proportion required to burn t0 Dum it? °

1-inch of arsenicated hidrogen gas, in which the hidrogen

is fully saturated with arsenic at the common temperature.

All acids, in which the oxigen is feebly combined, de- Action of acid?, >
compose arsenicated hidrogen gas. This phenomenon is
very striking with nitric acid. While part of the hi- Nitric.
drogen, being condensed by the oxigen of the acid, is con-
verted into water, another part is set free. At the same
time the whole [?] of the arsenic is separated in the me-
tallic form, but is very quickly oxided by the nitric acid?
and at length acidified. The nitric acid acquires a yellow-
colour, and bubbles of nitrous oxide gas are extricated
from it. The gas that ultimately remains is pure hidrogen
mixed with nitrous oxide. Prof. Stromeyer employ* the
action of nitric acid on the arsenicated hidrogen gas, to
calculate the proportion of its principles, -which, ac-
cording to him are 10*600 arsenic, and 0*219 hidrogen.

Nitrous acid decomposes it instantaneously, and arse- xi'rju,s.
nious acid is deposited.

Oxigenized muriatic acid decomposes it, part of the lw- Oxigeniz.»d
drogen and arsenic undergoing combustion, and the other l^ttnatu;.
being separated. Oxigenized muriatic acid gas brought
into contact with it in narrow tubes acts upon it in the
same manner as the liquid acid : but if the two gasses be
mixed in a wide jar, the whole of the arsenic is instantly
converted into arsenious acid, appearing as a white va-
pour ;

384 SCIENTIFIC NEWS.

pour ; while part of the hidrogen forms water, and another
part appears as pure hidrogen gas.

Other acids. Sulphuric, phosphoric, and arsenic acid, equally de-

compose this gas ; but the effect is produced very slowly,
and the arsenic is deposited for the most part in the me-
tallic form. In the decomposition of this gas by acids in
general, a very perceptible increase of volume takes place
at the commencement of the process.

Add solutions Most of the solutions of the metals in acids likewise de-
compose it. The hidrogen is in part burned by the disoxi-
genation of the metallic oxide, and in many cases by the
disoxigenation of the acid likewise, with which the metal
was combined, and forms water, while another part is
converted into pure hidrogen gas. Thus the other com-
ponent part, the arsenic, is separated, and in most cases,
at least at the commencement, appears as a pure metal :
but in general, if the acid have a weak affinity for oxigen and
the oxide, or if the metal dissolved in it be highly oxided, the
arsenic is soon converted into oxide, and thence into ar-

Corrosive mil- senious, or sometimes into arsenic acid. This is most
striking with the corrosive muriate of mercury, which in
this experiment is converted into mild muriate. This mc-

tesSTofft la'l'c sa^ *s sucn a sensible test of arsenicated hidrogen gas,

that it is capable of detecting it when mixed with ten thou-
sand times its bulk of atmospheric air, or of pure hidro-
gen, as was found by experiment.

Kemarkable prof. Stromeyer concluded with a remarkable experi-

pentine. ment, showing the effect of oil of turpentine on arseni-

cated hidrogen gas, all the phenomena of which however
do not appear easily explicable. Ten cubic inches of the
gas being confined over this essential oil, all the arsenic was
separated in the course of ten hours, so as to leave the hi-
drogen gas pure. No perceptible deposition of metal or
oxide took place; but the oil appeared milky and viscous ;
and after some time small sixsided crystals, terminating in
pyramids, were found adhering to the sides of the vessel.
These crystals, being set on lire, burnt like oil of turpen-
tine, emitting at the same time a very distinguishable smell
of arsenious acid. A similar appearance took place on
transmitting arsenicated hidrogen gas through oil of tur-
pentine.

riate of mer-
cury

INDEX.

ACCIDENTS from the sudden de-
composition of potash, 146

Acid contained in sweat, 63— In urine,
67— In milk, 72

Albinoes of Great Britain, account of,
81

Aldebaran, or th« Bull's eye, described,
9

Alkalies, decomposition of, 78, 156

Allen, Wm. Esq. and W. H. Pepys,
Esq. on the quantity of carbon in
• carbonic acid, and on the nature of
the diamond, 217

Altitude, meridian, new methods of
finding, 324

Analysis— Of Siderite or Lazulite, 20*-**
Of cream of tartar, 29— Of the py-
rophysalite, 33— Of animal acids, 63
—Of orpiment and realgar, 74— Of
the several species of Peruvian bark,
108, 203 — Of the fire-damp of coal-
mines, 149— Of slate, 380

Anderson, Dr. J. on home-made wines,
356

Anderson, C. Esq. 318

Andromeda's head, its situation and de-
scription, 5, 173

Angustura bark, compared with that of
Peru, 120

Animal torpidity, 161

Antares described, 6

Aquarius, its situation, 9

Aquila, described, 6

Arc of the meridian measured in India,
309

Arcet, M, de, his process for obtaining
pure barytes, 2 >

Arcturus described, 2

Arips described, 4
Vol. XIX.

Attraction of surfaces, 14
Auriga, its situation, 4

B.

Banks, Sir J. on the revival of an ob-
solete mode of managing strawberry
beds, 95— Letter to, on the forma-
tion of the bark of trees, 241— On
the economy of bees, 253— See 318

Barclay, Dr. 318

Bark of trees, formation of, 241

Bark, Angustura, 120

of cherry-tree, 119

of oak, 119

Peruvian, experiments on several

species of, 106, 203— Compared with
various vegetable substances, 119

of white willow, 120

Barker, Mr. 335

Barraud, Mr. description of his mercu-
rial pendulum, 258
Barytes, pure, preparation of, 23

hydroguretted sulphuret of, 25

Bason, mineral, in Wales, 361
Bassia butyracea, the, described, 372
— — obovata, 376

Beccaria, M. 50, 59

Bees, natural history and economy of,

250
Bennet, Mr. his electrical experiments,

44
Berger, Dr. on the heights of several

places in France, 272
Bergman, M. on orpiment and realgar,

74
Bernhardi, M. see Trommsdorff
Berthollet's electrical experiments, 51
Berzelius, see Hisinger
Black, Dr. 199, 201
Blight in wheat, its cause and preven*

tion, 338

b Blind

I N D E X.

Blind restored to sight, 99

Blumcnbach, Professor, on Albinoes, 82

Bonpland, M. 116

Bouillay, see Vauquelin

Bradley, Dr on the undulatory Telo-
city of light, 144

Brougham, Mr. on coloured concentric
ring-; between object glasses, 195

Buch, M. Von, 318

Bucholz on the analysis of slate, 380

Butter-tree of the East Indies, a bota-
nical and economical account of,
372

Buzzi, M. onAlbinoes, 82

C.

Cader Idris, a mountain in Wales, for-
merly a volcano, 237
Cadet, C A. on a property of cam-
phorated water, 26— —On mineral
acids, 64

Calomel, new mode of preparing, 240
Calorimeter, a newly invented one, 197
Camphorated water, 26
Cancer, the constellation, described, 4
Capella, its situation, 2, 4, 173
Capricorn, its situation and descrip-
tion, 8
Carbon, quantity of, in carbonic acid,

216
Cassiopeia described, 1
Cataracts of the eyes removed from pa-
tients bom blind, 99
Cavallo, M. his electrical multiplier,

45
Cavendish, Mr. 101— His discoveries in
electricity, 43— His analysis of corn-
won air, 87
Centaury compared with Peruvian bark,

120 .
Ccphesu-, its situation pointed out, 2
Chaulnes, Duke of, on coloured con-
centric rings produced by laying two
obi ect- glasses upon each other, 194
Chemical theory, the modern, objec-
tions to, 170
Chemical tables, 381

" Chemist, A," his correction of some

mis-statements in the account of Mr.

Davy's decomposition of the fixe*

alkalies, 147

Cherry-tree bark compared, with that of

Peru, 119
Cheselden on the cataract of the eye,

99, 105
Chcvreul, see Robiquet
Chinese radish oil, economical and me*

dicinal uses of, 79
Cinchona, experiments on several spe-
cies of 106, 203
Cogan, Dr. on the culture of the poppy

for oil, 282
Colours, experiments pn the cause of,

121, 177
Columella, 175

Comet expected last January, observa-
tions on, 263
Constellations, a guide to, 1, 11, 173,
Cor Leonis, its situation, 4
Corona Borealis, its situation and de?

scription, 6
Coromandel coast, measurement of a

degree at, 309
Corvus, its situation in the heavens, 6
Cotus, its situation and description, 9
Coulomb, M. his electrical balance, 45
Crater, its situation in the heavens, 6
Crawford, Dr. his experiments on heat

erroneous, 199, 200, 201
Cream of tartar contains lime, 2Q
Cuthbertson, Mr. his electrometer, 45,

153
Cygnus, description of its appearance
and situation in the heavens, 2, 5,

P.

Dalton, Mr on the gas of standing

water, 150
D'Arcet, see Arcet
Darwin, Dr. 248, S29
Davis, Mr. his improved machine for

painters and glaziers, 13— On the

blight in wheat, 338

Davy,

INDEX.

t)avy, Mr. on the decomposition of al-
kalies, 13j 78, 146, 156, 172— On

t the analysis of air, 88 — On some
cUemical agents of electricity, 57

Decandolle, M. abstract of his Essay on
the medicinal properties of plants,
compared with their external form
and natural classsification, 17

Decay of wood, prevention of, 328

Del planus, its situation, 9

De Luc, Dr; 199

Deschamps, jun. M. his discovery of a
peculiar salt in Peruvian bark* 212

Destouches, M on the lime in cream
of tartar, 20

Deyeux, M. on animal acids, 64

Diamond, experiments on the nature
of the, 226

Dispan, M. his observations on the pre-
tended attraction of surfaces, answer-
ed, 14

Donovan, Mr. his account of an ex-
tinct volcano in Britain, 237

Draco, the constellation, described, 2

Drugs, indication of their virtues, 17

Da Hamel, see Hamel

Du Pont, see Pont

Dytiscusona pamphlet lately published
by the Itcv. S. Vince, on the cause
of gravitation, 304 — Answered, 344

E.

Eclipse of the sun, 16th June, 1806,

remarks oh, 321
Ecliptic, pole of, directions for finding,

10
Edinburgh, a new society of natural

history established at, 317
Electricity, 37
Estner, M. 20

Eudiometer, a new one, described, 86
Eys, Mr. S. N. Van, on poppy oil,

292

Fairy rings, 343

Family wine making, improvements in,

353
Fire-damp of coal mines, experiments

on, 149
Fisher, Mr. G. A. 291
Fixed stars, table of their distances from

each other, 1 1
Fomalhaut, its situation, 9
Forster's Bassia obovata, 376
Fourcroy, M. his analysis of Peruvian

bark, 115 — Mistake in his Chemical

System, 382
Fullerton, Lieut. Col. 318
Friesleben, Mr. 318

Gahn, M. on the fluoric acid contained
in the stone, called pyrophysalite, 36

Galvanic trough, improvement in, 148

Galvanism, 156, 170

Garnett, J. Esq. on the total eclipse of
the sun on the 16th of June, 1806;
with some new methods of finding
the sun or moon's meridian altitude,
and the approximate time, by altitudes
taken near the time of noon, 321

Gemini, their situation and appearance,
5, 173

" Geognosy, Elements of," a work re-
cently published, 319

Geological observations in France, con-
cluded from Vol. XVI II. 272

Germander compared with Peruvian
bark, 120

Gibber, Dr. on the non-existence of
oxigen and hidrogen as bases of par-
ticular gases; the action of galva-
nism } and the compound nature of
heat, 170

Glaziers, see Painter*

Gleditsch,
bl

INDEX.

Gleditsch, M. 17

Gmelin, M. 17

Gott, Mr his account of the vegeta-
ble butter of India, 377, 378

Gough, Mr. on torpidity in animals,
161

Grafting, advantages of, 175

Grandi, M. de, 79

Grass, sTiped or ribband, excellent food
for cattle, 500

Gravitation, investigation of its causes,
£04, 344

Gravity, specific, of air, 145 — Of light
148, 145— Of water, 145

Grenville, Hon. C. F. 361

Grew, on the formation of the bark of
trees, 241

Guide to the constellations, 1, 11 —

Corrected, 173
Guyton de Morveau, M. on lazulite,
23— On cohesion, 59— On the ana-
lysis of air, 88 — On the combustion
of the diamond, 2 16

H.

Haberre, M. 380

Habits of animals, remarkable effects
of, 255

Hales, the first who observed the ab-
sorption of air in certain cases, 87—
On the comparative velocity of air
and water, 144 — His theory of the
formation of the bark of trees, 242

Hallett, Mr. on the use of tobacco-water
in preserving fruit crops, by destroy-
ing insects; and on the use of the
striped or ribband grass, 298, 301

Harnel, Du, on the formation of the
bark of trees, 242

Hatche'tt, Charles, Esq. communica-
tion from, containing a description"
o; a new eudiometer, by W. H. Pe-
pys, Esq. accompanied with experi-
la'.ju'.'s elucidating its application, 86

Hauy,M. 37 I

Heights of various places in France,
concluded from Vol. XVIII. 272,
277
Heim, M. his analysis of thesiderile,

20
Helvetius on Albinoes, 82
Henry, Dr. W. his experiments on the

fire-damp of coal-mines, T 19
Hercules, its situation and description, 7
Herschell, Dr. on the cause of colour-
ed concentric rings between two ob-
ject-glasses laid upon each other, as
discovered by Sir Isaac Newton, 121,
177— On the nature of the new ce-
lestial body discovered by Dr. Olbers,
and on the comet which was expected
to appear last January in its return
from the sun, 259
Herder, Mr. 318
Hisinger and Berzelius, their analysis

of a s-tone called pyrophysalite, 33
Home, Ev. Esq. his account of two-
children born with cataracts in their
eyes, to shew that their sight wa9
obscured in very different degrees ;
with experiments to determine the
proportional knowledge of objects ac-
acquired by them immediately after
the cataracts were removed, 99 — On
the structure of the different cavi-
ties which constitute the stomach of
the whale, compared with those of
ruminating animals, with a view to
ascertain the situation of the digest-
ive organ, 348
Humboldt, M. Von, 116, 318
Hunter, Mr. J. on the economy of
bees, 256 — On the 'cavities in the
stomach of the whale, 350
Hutton, Dr. remarks on his theory of
granite, 319— His observations on
f.iry rings, 368
Huygens, M. 121
Hydra, its situation described, 6

India,

INDEX.

India, measurement of a degree in,

309
Insects destroyed by tobacco- water, 298,

SOI
Irvine, Dr. 199
Isenflamm, 17

J.

Jameson, R. Esq. 318— -His system of
mineralogy, 319

J. G. C. his improvement in the Galva-
nic trough, to prevent the cement
from being melted, when the action
is very powerful, 148

Jussieu, 17

K.

Karsten, Professor, 318

Kirwan, R. Esq. 318

Klaproth, his experiments on the La-
zulite of Vorau, 20— On the topaz,
37— On slate, 380— See 3 18

Knight, T. A. Esq. on raising new and
early varieties of the potato, 97 — On
the advantages of grafting walnut,
mulberry, and chesnut trees, 175—

| On the formation of the bark of trees,
241— On the economy of bees, 250

La Lande, his account of the relative
situations of the different stars, by
which the principal constellations
may be distinguished, 1 — Corrections
of some errors in his catalogue, 174

Lanibton, Major W. his account of the
measurement of an arc of the meri-
dian on the coast of Coromandel,
309

Language of brutes, 253

Laplace and Lavoisiei's calorimeter de-
fective, 197

Lavoisier, on the quantity of carbon
contained in carbonic acid, 21G — On
the base of potash, 308

Lazulite, analysis of, 20

Lectures at St. Thomas's and Guy**
Hospitals, 160

Lcdhuy, Mr. A. his new musical in-
strument described, 371

Leo, its situation and appearance, 4

Libra, its situation in the heavens, 6

Light, specific gravity of, 143

Lime in cream of tartar, 28

Linnrus, 17

Lyra, directions for discovering, 2, €

Lyre, organized, 371

M.

Macnight, Rev. T. 318

Malpighi's theory of the formation of
the bark of trees, 241

Mammoth found in a perfect state
157

Martin, Mr. E. his description of the
mineral bason in the eounties of
Monmouth, Glamorgan, Brecon,
Caermarthen, and Pembroke, 361

Maskeleyne, Dr. 144

Matthews, W. Esq. on family wine-
making, 353

Maupertuis, on albinoes, 82

Meridian, measurement of an aTc of, on
the coast of Coromandel, 309

Meuder, Mr. 318

Milk, analysis of, 72

Mineral bason in Wales, 361

Mineralogy, 318

Mirbel on the formation of the bark of
trees, 242

Mohs, Mr. F. 20, 318

Moll, Baron, 20 ^

Mont Blanc, brief description of some
mountains in the department of, 272

Morozzo, 219

Mountains in France, 272, 277

Musical instrument, called an organ*
ized lyre, .371

Uairne,

INDEX.

Naime, Mr. his electrical machine, 43

*leu, P. Esq. 318

Newton, Sir. I. his discovery of colour-
ed concentric rings between two ob-
ject-glasses, laid one upon the other,
121, 177— On light, 143

>}. R. D. letter from, containing some
remarks on, and emendations of La
Lande's guide to the constellations,
173

Nutgalls compared with Peruvian bark,
119

Oakcs, Mr. 156, 307

Oil of the Chinese radish, 79

Olbers, Dr. on the nature of the new

celestial body discovered by him, 259
Oliviero, Dr. Francis de, BO
Ophiucus, or Serpentarius, its situation

and description, 7, 173
Orion described, 3, 4
Orpiment examined, 74

P.

Painters and Glaziers, improved ma-
chine for, 13

Pallas, M. his experiment at conquer-
ing the torpid disposition of a mar-
mot, 169

Park, Mungo, his account of the but-
ter-tree of Africa, 376

Parry, Dr. on the causes of the decay of
wood, and the means of preventing
it, 328

Paul, Mr on camphorated water, 26

Pt-gasus, description of its appearance
and situation among the stars, 5

Pendulum, a mercurial, described, 258

Pcpy*, W. II. Esq. bis new eudiometer
described, 86 — On the quantity of
carbon in carbonic acid, and on the
nature of the diamond, 216

Perseus, the constellation, described, 4

Peruvian bark, see Bark.

Philommatos's account of an accident
from the sudden deflagration of the
base of potash) 146

Phosphorescence of bodies froril the
action of the electric explosion, 153

Pisces, its situation and description, 10,
174

Plants, medicinal properties of, 17

Playfair, Professor, on veins of mine-
rals, 319

PIaz, 17

Pleiades, the, described, 3

Plot, Dr. 168

Pole of the ecliptic, directions for find-
ing, 10.

Pont de Nemours, M. Du, on the tor-
pidity of animals, 161

Poppy, culture of, for oil, 282

Poske, Mr. 290

Potash, decomposition of, by Galva-
nism, 156

Potash and its base, experiments and
observations on, 307

Pott, Mr. on the cataract of the eye,
106

Potatos, on raising new and early va-
rieties of, 97

Prato, Dr. J. C. de, in answer to some
observations of M. Dispan, on the
pretended attraction of surface be-
tween oil and water, 14

Priestley, Dr. on the different kinds of
air, 87

Procyon, its situation and appearance,. 3

Proust, M. on orpiment, 75

Pyrophysalite, description and chemical
analysis of, 33

P.

Raphanus Sinensis, 80

Reade, Dr. J. description of his newly

invented calorimeter, 197
Realgar examined, 74
Regulus, its situation, 4
Reus, M. 380

Rigel,

INDEX.

Rigel, its situation in the heavens, 3

Hitter, M.23

Robiquet, on the preparation of pure
barytes, 23

Robiquet and Chevreul on the sponta-
neous decomposition of the hydrogu-
retted sulphuret of barytes, 25

Koofs of houses, improved, 266

Kouppe, 219

Roxburgh, Dr. his botanical and eco-
nomical account of the butter- tree of
the East Indies, 372

Boy, General, 3 15

Rumination in animals, 348

Sagittarius, its situation and descrip-
tion, 6

Salting and smoking meat, expeditious
and simple process for, 80

Saussure, M. on albiuoes, 81, 83

Schroeter, M. on the planet Vesta, 264

Scientific News, 78, 157, 240, 317, 381

Scorpio described, 6

Seguin, M. a mistake of, relative to the
aqueous infusions of Peruvian bark,
107

Siderite, thct analysis of, 20

Sight restored to two children born with
cataracts, with experiments to deter-
mine the proportional knowledge of
objects acquired by them immediately
after restoration, 99

Sifius, described, 3

Skrimshire, jun. Mr. W. on the phos-
phorescence of bodies, from the action
of the electric explosion, 153

Slate, analysis of, 3S0

Slating houses, new method of, 266

Salome, M. 115

Spallanzani, Signor, 167

Specific gravity, see Gravity.

Spica Virginis, described, 6

Stars, an account of the relative situa-
tion of, by which the principal con-
stellations may be distinguished, 1,
U, 176

Stomach of the whale, on the structure
of, compared with that of ruminating
animals, 348

Strawberry beds, management of, 95

Stromeyer, Dr. account of his chemi-
cal tools, 381

Surfaces, attraction of, 14

Sweat, analysis of, 63

Sylvester, Mr. C on the advantages of
malleable zinc, and the purposes to
which it may be applied, 1 1— On the
decomposition of the fixed alkalis by.
Galvanism, 156— His experiments
and observations on potash and it*
base, 307

T.

Tan compared with Peruvian bark, 119

Tartar, cream of, contains lime, 29

Tennant, S. Esq. on the nature of the
diamond, 217

Thenard, M. on the analysis of sweat,
the acid it contains, and the acids of
urine and milk, 63— On orpiment
and realgar, 74

Thomson, Dr. T. on the fire-damp of
coal mines, 1 50— See 318

Timber saved in building, 266

Tobacco -water, its use in destroying
insects, 298, 301

Torpidity of animals, 161

Traill, Dr. his account of two children
born in England, with the character-
istics of Alniuoes, 81

TrommsdorfF and Bernhardi, their ana-
lysis of the siderite or lazulite, 20

Tugwell, Mr. his new method of slating
houses, described, 266

V.

Van Eys, see Eys.

Vauquelinand Bouillay, their Report on

a memoir of M. Dcstouches on the

lime of cream of tartar, 20

Vauquelin,

INDEX.

Vauquelin, M, his experiments on

the various species of cinchona, 106,

203
Veins of minerals divided into two

orders, 318
Vesta, observations on the planet so

called, 259, 264
Vince, Mr. remarks on his pamphlet

respecting the cause of gravitation,

304— Answered by the author, 344
Vogel, 17
Volcano, extinct, in Britain, account

of one, 237
Voha's pile, experimental observations

on, 54

Urine, analysis of, 67
Ursa Major described, 1
■ ■ ■■■ Minor described, 2

W.

Walker, P. Esq. 318

Ware, Mr. on the cataract of the eye,

100, 105
Wasps, economy of, 256
Water, camphorated, 26
Water-proof leather, receipt for making,

335
Werner, Professor, 518-— Observations

on his silex schistosus politorius poli-

erschiefer, 380
Wernerian Natural History Society at

Edinburgh, 317
Whale, stomach of the, on the structure

of the different cavities of which it
is constituted, 348

Wheat, blight in, 338

Wilka, 17

Wilke, M. 48

Willow bark compared with that of
Peru, 120

Wines made for family use, improve-
ments in, 353

Winter, Mr. R. on a method of finding
the specific gravity of light, and his
defence of the undulatory system,
143

Withering, Dr. on fairy rings, 368

W. N. on albinoes, 84— On Dr. Craw-
ford's theory of heat, 202 — On find-
ing a substitute for tobacco for the
purpose of destroying insects, 301

Wollaston, Dr. his improvements hi
electricity, 43, 44-*On fairy rings,
367

Wood, decay of, inquiry into the causes
' of, and the means of preventing it,
328

Wright, Dr. 318

Y.

Young, Dr. his experiments favourable
to the undulatory system of light,
143

Z,

Zinc, malleable, uses to which it may
be applied, 1 1

END OF THE NINETEENTH VOLUME.

Stratford, Printer, Crown Court, Temple-Bar.